Note: Descriptions are shown in the official language in which they were submitted.
x;2170019
1
A Porous, Crystallized, Aromatic Polycarbonate
Prepolymer, A Porous, Crystallized Aromatic
Polycarbonate, And Production Methods
This application is a divisional of Canadian
application no. 2,000,163 filed October 4, 1989.
Technical Field
The present invention relates to a porous,
crystallized, aromatic polycarbonate prepolymer, a
porous, crystallized aromatic polycarbonate, and
production methods therefor. More particularly, the
present invention is concerned with a porous, crys-
tallized, aromatic polycarbonate prepolymer having
terminal hydroxyl and aryl carbonate groups in a
specific molar ratio and having a specific number
average molecular weight, surface area and crystal-
linity, which can readily be converted by solid-
state condensation polymerization to a porous, crys-
tallized aromatic polycarbonate having excellent
properties. The porous, crystallized aromatic
polycarbonate of the present invention can readily
be molded to obtain a shaped, porous, crystallized
polycarbonate. The porous, crystallized aromatic
polycarbonate and the shaped, porous, crystallized
polycarbonate of the present invention have excel-
.210019
2
lent heat resistance and solvent resistance and
exhibit advantageously low water absorption so that
they are suited for use as a filter material or an
adsorbent. The porous, crystallized aromatic poly-
carbonate and the shaped porous, crystallized poly-
carbonate of the present invention can also be readi-
ly molded by a melt process into an article useful
as engineering plastics, such as an optical element
and an electronic component, which is appreciated
since it is free of impurities, such as chlorine-
containing compounds, and has excellent properties.
Background Art
In recent years, aromatic polycarbonates have
been widely employed in various fields as engineer-
ing plastics which have excellent heat resistance,
impact resistance and transparency. Various
studies have been made with respect to processes for
producing aromatic polycarbonates. Up to now pro-
cesses, such as one utilizing interfacial conden-
sation polymerization of an aromatic dihydroxy com-
pound, such as 2,2-bis(4-hydroxyphenyl)propane
(hereinafter frequently referred to as "bisphenol
A"), with phosgene (hereinafter frequently referred
to as the "phosgene process"), have been commercial-
ly practiced. In the phosgene process, a mixed
.2170019
3
solvent of water or an aqueous alkali solution and a
water-immiscible organic solvent is generally used.
Commercially, a mixed solvent of an aqueous sodium
hydroxide solution and methylene chloride is
employed. As a catalyst for polymerization, a
tertiary amine or 'a quaternary ammonium compound is
employed. By-produced hydrogen chloride is removed
as a salt with a base.
However, in the interfacial condensation poly-
merization process employing phosgene, (1) toxic
phosgene must be used; (2) due to the by-produced
chlorine-containing compounds, such as hydrogen
chloride and sodium chloride, the apparatus used is
likely to be corroded; (3) it is difficult to remove
impurities which adversely influence the polymer
properties, such as sodium chloride, from the poly-
mer; and (4) since methylene chloride (which is
generally used as a reaction solvent) is a good
solvent for polycarbonate and has a strong affinity
to polycarbonate, methylene chloride inevitably
remains in produced polycarbonate. Removal of the
remaining methylene chloride on a commercial scale
is extremely costly, and complete removal of the
remaining methylene chloride from the obtained poly-
carbonate is almost impossible. Further, it is
._ 1.2170019
4
noted that the methylene chloride remaining in the
polymer is likely to be decomposed, e.g., by heat at
the time of molding, thereby forming hydrogen chlo-
ride, which not only causes corrosion of a molding
machine but also lowers the quality of the polymer.
Furthermore, when~it is intended to produce a poly-
carbonate having a high molecular weight (e. g.,
number average molecular weight of 15,000 or more),
a methylene chloride solution of such a polycarbon-
ate has an extremely high viscosity, thereby
making agitation of the solution difficult. Addi-
tionally, sticky polymer solution is produced, and
hence it becomes extremely difficult to separate the
polymer from methylene chloride. Therefore, commer-
cial production of a high quality, high molecular
weight polycarbonate by the phosgene process is
extremely difficult.
As mentioned above, the phosgene process
involves too many problems to be practiced
commercially.
Meanwhile, various methods are known in which
an aromatic polycarbonate is produced from an aroma-
tic dihydroxy compound and a diaryl carbonate. For
example, a process, which is generally known as a
transesterification process or a melt process, is
_170019
s
commercially practiced. In this process, a poly-
carbonate is produced by performing a molten-state
ester exchange reaction between bisphenol A and
Biphenyl carbonate in the presence of a catalyst,
while effecting elimination of phenol. However, in
order to attain the desired polymerization degree of
the final aromatic polycarbonate according to this
process, phenol and, finally, Biphenyl carbonate
need to be distilled off from a formed molten poly-
carbonate of high viscosity (e. g., 8,000 to 20,000
poise at 280 °C), and it is generally necessary to
perform the reaction at a temperature as high as
280° to 310 °C in vacuo as high as 1 mmHg or less
for a period of time as long as, e.g., 4 to s hours.
is Therefore, this process has many disadvantages. For
example, (1) both special apparatus (suitable for
reaction at high temperatures and under high vacuum)
and a special stirrer of great power (useful under
the high viscosity conditions of the product to be
formed) are needed; (2) due to the high viscosity of
the product, when a reactor or stirring type reactor
(which is usually employed in the plastic industry)
is used, only a polymer having a weight average
molecular weight as low as about 30,000 is obtained;
(3) due to the high temperature at which the reac-
_2~~oo~s
6
tion is performed, branching and crosslinking of the
polymer are likely to occur, thereby rendering it
difficult to obtain a polymer of good quality; and
(4) due to long residence time at high temperatures,
S discoloration of the polymer is likely to occur [see
Mikio Matsukane et al, Purasuchikku Zairyo Koza 5
"Porikaboneito Jushi" (Seminar on Plastic Materials
5, "Polycarbonate Resin"), Nikkan Kogyo Shinbun
Publishing Co., p.62-67, Japan (1969)].
Moreover, with respect to the polycarbonate ob-
tained by the melt process, it is known that the
molecular weight distribution of the polymer is
broad, and that the proportion of branched structure
is high. Therefore, it is recognized that the poly-
carbonate produced by the melt process is inferior
to that produced by the phosgene process in proper-
ties, such as mechanical strength, and that, parti-
cularly, the polycarbonate produced by the melt
process is disadvantageous because of its brittle
fracture properties, and it is also poor in mold-
ability because of its non-Newtonian flow behavior
[see Mikio Matsukane, "Kobunshi" (High Polymer),
Japan, Vol. 27, p.521 (1978)].
Meanwhile, in the production of polyhexameth- -
ylene adipamide (nylon 66) and polyethylene tere-
21 7 00 1 9
phthalate (PET), which are examples of the most
popular condensation polymerized polymers, polymeri-
zation is generally conducted by a melt polymeriza-
tion process until the polymer has a molecular
weight at which mechanical properties sufficient for
a plastic or a fiber are exhibited. With respect to
this production, it is known that the polymerization
degree of the thus produced polymer can be further
increased by solid-state condensation polymerization
in which the polymer is heated at a temperature (at
which the polymer can remain in solid-state) at a
reduced pressure or atmospheric pressure under a
stream of, e.g., dry nitrogen. In this polymeriza-
tion, it is believed that dehydration condensation
is advanced in the solid polymer by the reaction of
terminal carboxyl groups with adjacent terminal
amino groups or terminal hydroxyl groups. Also, in
the case of polyethylene terephthalate, condensation
reaction by the elimination of ethylene glycol from
the formed polymer occurs to some extent simultaneo-
usly with a condensation reaction between functional
groups.
The reason why the polymerization degree of
nylon 66 and polyethylene terephthate can be in-
creased by solid-state condensation polymerization
217009
a
is that these polymers are inherently crystalline
polymers having a high melting point (e.g., 265 °C
and 260 °C) and, hence, these polymers can remain
sufficiently in solid-state at a temperature at
which solid-state polymerization proceeds (e. g.,
230 °C to 250 °C).' What is more important is that,
for the above-mentioned polymers, the compounds to
be eliminated are substances, such as water and
ethylene glycol, that have a low molecular weight
and relatively low boiling point and, therefore, can
readily move within and through the solid polymer so
that they can be removed from the reaction system as
gases.
On the other hand, it has been proposed to
employ a method for producing an aromatic polyester
carbonate having a high molecular weight in which a
high melting temperature aromatic polyester carbon-
ate having both an aromatic ester bond and an aroma-
tic carbonate bond is subjected to melt polymeriza-
tion, and then subjected to solid-state condensation
polymerization. According to this method, an
aromatic dicarboxylic acid or aromatic oxycarboxylic
acid, such as naphthalene dicarboxylic acid, p-
hydroxybenzoic acid or terephthalic acid, is reacted
with an aromatic dihydroxy compound and a diaryl
1.170019
9
carbonate in their molten state to prepare a pre-
polymer. Then, the prepolymer is crystallized and
subjected to solid-state condensation polymeriza-
tion. If the polymerization degree is increased to
some extent by melt polymerization at 260°to 280°C,
when p-hydroxybenzoic acid is used, the resultant
product is no longer in a molten state but becomes
solid. Since the resultant solid is a prepolymer
having high crystallinity and a high melting temper-
ature, it is not necessary to crystallize the solid
further (see Japanese Patent Application Laid-Open
Specification No. 48-22593, Japanese Patent Applica-
tion Laid-Open Specification No. 49-31796, USP
4,107,143, Japanese Patent Application Laid-Open
Specification No. 55-98224). However, these methods
apply only to the production of an aromatic poly-
ester carbonate containing 30% or more, generally
50% or more, of ester bonds, and it has been
reported that, although an aromatic polyester
carbonate containing less than 30 % of ester bonds
was intended to be produced, fusion of a prepolymer
occurred at the time of solid-state polymerization
so that the solid-state condensation polymerization
could not be conducted (Japanese Patent Application
Laid-Open Specification No. 55-98224).
~_ 2170019
,o
On the other hand, it is known that the pre-
sence of ester bonds as mentioned above promotes the
carbonate bond-forming reaction when an aromatic
polyester carbonate is produced by a melt condensa-
tion polymerization method (see Japanese Patent
Application Publication Specification No. 52-36797).
According to the Japanese Patent Application Publi-
cation Specification No 52-36797, when a high mole-
cular weight aromatic polycarbonate having ester
bonds is produced by melt condensation polymeriza-
tion, the melt condensation polymerization reaction
is markedly promoted by introducing ester bonds, in
advance, into the molecular chain of an aromatic
polycarbonate having a low polymerization degree.
Naturally, it is believed that the above-mentioned
effect of promoting the condensation polymerization
reaction by the ester bonds may also be exhibited at
the time of solid-state condensation polymerization.
Therefore, it is relatively facile to increase the
polymerization degree by solid-state condensation
polymerization with respect to an inherently crys-
talline aromatic polyester carbonate having a high
melting temperature, for example, a polymer having
40 mole $ of ester bonds obtained from p-hydroxyben-
zoic acid, hydroquinone and Biphenyl carbonate, or
r 2170019
an aromatic polyester carbonate (such as a polymer
having 55 mole % of ester bonds obtained from 2,6-
naphthalene dicarboxylic acid, bisphenol A and
Biphenyl carbonate) which can easily become a crys-
talline polymer having a high melting temperature,
by a simple crystallizing operation, for example, by
heating at a predetermined temperature lower than
the melting temperature.
However, no attempt has been made by any persons
skilled in the art other than the group of the
present inventors to produce a high molecular weight
aromatic polycarbonate containing no ester bond by a
method in which a prepolymer having a low molecular
weight is first prepared by melt polymerization, and
then the polymerization degree of the prepolymer is
increased by solid-state condensation polymeriza-
tion, except for the case where a specific highly
crystalline polycarbonate having a melting tempera-
ture as high as 280 °C or more has been produced by
solid-state condensation polymerization (see Example
3 of Japanese Patent Application Laid-open Specifi-
cation No. 52-109591). Japanese Patent Application
Laid-open Specification No. 52-109591 discloses a
method in which melt polymerization of an aromatic
dihydroxy compound comprising about 70 % of hydro-
._ 2170019
12
quinone and about 30 % of bisphenol A with diphenyl
carbonate is conducted at 280 °C under an extremely
reduced pressure, i.e., 0.5 mmHg to form a solidi-
fied prepolymer having a melting temperature of more
than 280 °C, and then the polymerization degree of
the prepolymer is'increased by solid-state condensa-
tion polymerization at 280 °C under 0.5 mmHg for 4
hours.
However, with respect to a substantially amor-
phous aromatic polycarbonate comprised mainly of a
dihydroxydiaryl alkane, such as bisphenol A, no
noteworthy attempt has been made by any persons
skilled in the art other than the group of the
present inventors to produce a polymer having a high
molecular weight by first forming a prepolymer
having a relatively low molecular weight and then
subjecting the prepolymer to solid-state condensation
polymerization. For example, in the phosgene
process using an acid acceptor, which is the most
representative method for producing an aromatic
polycarbonate, since a compound, such as sodium
chloride, to be removed from the reaction system to
advance the condensation reaction is generally solid
in the absence of a solvent, the compound hardly
moves within and through the solid polymer. There-
21700 9g
13
fore, it is difficult to remove the compound from
the reaction system. It is thus not feasible to
carry out this method using phosgene in a solid
state condensation system.
With respect to a method for producing the most
popular aromatic polycarbonate,i.e., a polycarbonate
derived from bisphenol A by transesterification
between bisphenol A and Biphenyl carbonate, all of
the studies have been directed toward a melt poly-
merization process at high temperature under highly
reduced pressure. Studies of any persons skilled
in the art other than the group of the present
inventors have never been directed toward a method
in which a prepolymer having a relatively low poly-
merization degree is first prepared, and then the
polymerization degree of the prepolymer is increased
by solid-state condensation polymerization to obtain
a polycarbonate having a high molecular weight.
Because polycarbonates derived from bisphenol A are
amorphous polymers having a glass transition tem-
perature (Tg) of from 149°to 150 °C, it has been
considered to be infeasible to subject polycarbon-
ates derived from bisphenol A to solid-state conden-
sation polymerization. In other words, in order for
a prepolymer to be susceptible to solid-state con-
21 7 p0 1g
14
densation polymerization, it is generally required
that the prepolymer not be fused but maintain its
solid-state at a temperature higher than the glass
transition temperature of the prepolymer (if the
temperature is lower than the glass transition tem-
perature of the prepolymer, molecular motion does
not occur, thus precluding solid-state condensation
polymerization). Amorphous polycarbonate which
melts at a temperature of 150 °C or more is prac-
tically not susceptible to solid-state condensation
polymerization.
The only proposals hitherto made for producing
an aromatic polycarbonate comprised mainly of a
dihydroxydiaryl alkane, such as bisphenol A, which
is a substantially amorphous polymer, by solid-state
condensation polymerization, are those disclosed by
the group of the present inventors in Japanese
Patent Application Laid-Open Specifications No. 63-
223035, No. 64-1725, No. 64-4617, No. 64-16826 and
No. 64-16827.
Japanese Patent Application Laid-Open Specifi-
cations No. 63-223035 and No. 64-4617 disclose that
solid-state condensation polymerization can be ef-
fected in the production of a polycarbonate of bis-
phenol A by self condensation reaction of a bisalkyl
21 7 00 19
,5
carbonate of an aromatic dihydroxy compound, e.g.,
bis(methyl carbonate)of bisphenol A represented by
the formula:
CH3
CH ~ U O
3 ~ ~ 3 (I)
H3
in which dimethyl carbonate groups are removed at an
elevated temperature. In particular, in the methods
of Japanese Patent Application Laid-Open Specifica-
tions No. 63-223035 and No. 64-4617, pre-polymeriza-
tion is performed to obtain a prepolymer having
methyl carbonate groups at both terminals thereof
which is represented by the formula:
U CH3 O
2 0 CH3aC0 O -~-- p~p CH 3 ~ I I ~
H3
wherein ,t is an integer of from 2 to about 30,
the prepolymer is subjected to solvent or heating
treatment for effectuating crystallization of the
._. ~, X1700 19
16
prepolymer, and then solid-state condensation poly-
merization is performed.
On the other hand, Japanese Patent Application
Laid-Open Specifications No. 64-1725, No. 64-16826
and No. 64-16827 disclose that a polycarbonate of
bisphenol A can be produced by reacting, for example,
bis(methyl carbonate)of bisphenol A represented by
formula (I) with Biphenyl carbonate to produce a
prepolymer having a methyl carbonate group and a
phenyl carbonate group as terminal groups [such as
that represented by the formula:
q 3 O
CH3 O>--- ~ p~p O ( I I I )
a
R
wherein .t is as defined above),
and subjecting the prepolymer to solvent or heating
treatment for crystallizing the prepolymer and then
to solid-state condensation polymerization. In the
methods of these patent application laid-open
specifications, as different from the methods of
Japanese Patent Application Laid-Open Specifications
No. 63-223035 and No. 64-4617, condensation poly-
merization is advanced by elimination reaction of
x_2170019
methyl phenyl carbonate from the terminal methyl
carbonate and phenyl carbonate groups.
Generally, in solid-state condensation poly-
merization, the polymerization temperature can be
low as compared to that in molten-state polymeriza-
tion. Accordingly, a major advantage of a solid-
state polymerization method resides in that the
thermal degradation of a polymer during the poly-
merization step is suppressed, and that hence a high
quality polymer is obtained. However, the solid-
state condensation polymerization has a grave draw-
back in that the polymerization rate is low. In the
method of producing an aromatic polycarbonate
through solid-state condensation polymerization
which is accompanied by the above-mentioned elimina-
tion reaction of dimethyl carbonate or methyl phenyl
carbonate groups as well, the polymerization rate is
not sufficiently high and hence a prolonged poly-
merization time has been necessary. A catalyst can
be used to increase the polymerization rate in
solid-state condensation polymerization. However,
the catalyst is likely to remain in the final poly-
mer, and hence the use of a catalyst is likely to
cause a problem of quality degradation of final
polymers (e.g., occurrence of silver streaks on the
_.. _ 21 7 00 19
,8
surface of a shaped article of polymers).
Disclosure Of The Invention
The present inventors previously found that
solid-state condensation polymerization could be
effectively performed to increase the molecular
weight of formed polycarbonate in the production of
an aromatic polycarbonate from, as starting mate-
rials, a dihydroxyaryl compound composed mainly of a
dihydroxydiaryl alkane, such as bisphenol A, and a
diaryl carbonate, such as Biphenyl carbonate, and
filed patent applications (Japanese Patent Publication
No. 63-240785,
and Japanese Patent Publication
No. 63-327678). These applications disclose methods
for producing a high quality aromatic polycarbonate
in which a substantially amorphous prepolymer having
hydroxyl and aryl carbonate groups as terminal
groups is crystallized and then subjected to solid-
state condensation polymerization, and the inven-
tions of the applications are based on an unexpected
finding that the crystallinity of a prepolymer plays
an important role in the practice of solid-state
condensation polymerization.
Ever since, the present inventors have
continued studies with respect to an improved method
B
21 7 00' 9
19
for producing an aromatic polycarbonate by solid-
state condensation polymerization. As a result,
unexpectedly, the present inventors have found that
the specific surface area of a crystallized aromatic
S polycarbonate prepolymer exerts a marked influence
upon the practice~of solid-state condensation poly-
merization. Further, the present inventors have
unexpectedly found that a porous, crystallized
aromatic polycarbonate prepolymer having terminal
hydroxyl and aryl carbonate groups in a specific
molar ratio and having specific number average mole-
cular weight, specific surface area and crystallini-
ty can readily be converted by solid-state condensa-
tion polymerization to a porous, crystallized,
aromatic polycarbonate having excellent properties.
Based on these unexpected findings, the present
invention has been completed.
Accordingly, it is an object of the present
invention to provide a porous, crystallized aromatic
polycarbonate prepolymer which can readily be
converted by solid-state condensation polymerization
to a porous, crystallized, aromatic polycarbonate
having excellent properties.
It is another object of the present invention
to provide an efficient method for producing the
_217009
above-mentioned prepolymer.
It is a further object of the present invention
to provide a porous, crystallized, aromatic
polycarbonate and a shaped, porous, crystallized
5 polycarbonate having excellent heat resistance and
solvent resistance, exhibiting advantageously low
water absorption and being free of impurities.
It is still a further object of the present
invention to provide an efficient method for produ-
10 cing each of the above-mentioned porous, crystal-
lazed, aromatic polycarbonate and shaped, porous,
crystallized, aromatic polycarbonate.
The foregoing and other objects, features and
advantages of the present invention will be apparent
15 from the following detailed description and appended
claims taken in connection with the accompanying
drawings.
In one aspect of the present invention, there
is provided a porous, crystallized, aromatic poly-
20 carbonate prepolymer comprising recurring aromatic
carbonate units and terminal hydroxyl and aryl
carbonate groups, wherein the molar ratio of the
terminal hydroxyl groups to the terminal aryl
carbonate groups is from 5/95 to 95/5, and having a
number average molecular weight of from 1,000 to
217009
21
15,000, a specific surface area of at least 0.2 m2/g
and a crystallinity of at least 5 %.
The porous, crystallized, aromatic polycarbonate
prepolymer of the present invention comprises
recurring aromatic carbonate units represented by
formula (IV):
0
II
EOCO-Ark (IV)
wherein Ar is a divalent aromatic group,
and terminal hydroxyl and aryl carbonate groups. The
terminal hydroxyl group (-OH) is directly bonded to
the aromatic group. The terminal aryl carbonate
group is represented by formula (V):
O
II
-OCOAr3 (V)
wherein Ar3 is a monovalent aromatic group.
The molar ratio of these terminal groups of the
prepolymer is not specifically restricted and varied
according to the number average molecular weight of
the prepolymer, the properties of an aromatic poly-
carbonate intended to be produced from the prepoly-
mer, and the like. Generally, the molar ratio of
O
Ii
-OH/-OCOAr3 is within the range of from 5/95 to
95/5, preferably from 10/90 to 90/10, more prefer-
21 7 flp ~g
22
ably 20/80 to 80/20.
With respect to the molar ratio of the terminal
groups of the prepolymer, an explanation is given
below, referring to a prepolymer having a number
average molecular weight of 4,000. When a ultra-
high molecular weight aromatic polycarbonate having
a molecular weight of,.for example, 15,000 or more
is intended to be produced from the prepolymer, it
O
II
is preferred that the molar ratio of -OH/-OCOAr3 of
the prepolymer be within the range of from 40/60 to
60/40, because a high polymerization rate can be
attained. Production of the ultra-high molecular
weight aromatic polycarbonate by the conventional
phosgene process or melt process (transesterifica-
tion process) is extremely difficult or impossible
because the viscosity of the polymerization reaction
mixture is rapidly increased before the intended
ultra-high molecular weight aromatic polycarbonate
is produced. However, by the method of the present
invention, a prepolymer having the above-mentioned
value of number average molecular weight and a molar
ratio of the terminal groups within the above-men-
tioned range can be polymerized without being sub-
jected to any influence of the viscosity of the
. 21700'i
23
reaction mixture. Therefore, by the use of the
above prepolymer of the present invention, an ultra-
high molecular weight aromatic polycarbonate can
advantageously be produced. When it is intended to
produce an aromatic polycarbonate (number average
molecular weight of 6,000 to 13,000) to be used for
injection molding or for extrusion molding, it is
preferred that the amount of the terminal hydroxyl
groups of the prepolymer be small relative to the
amount of the terminal aryl carbonate groups. That
is, it is preferred that the molar ratio of the
terminal groups of the prepolymer, namely the molar
O
II
ratio of -OH/-OCOAr3, be within the range of from
5/95 to 49/51. On the other hand, when it is
intended to produce an aromatic polycarbonate having
a chemically reactive terminal hydroxyl group in a
relatively large amount, it is preferred that the
O
I I
ratio of -OH/-OCOAr3 of the prepolymer be within the
range of from 51/49 to 95/5.
The porous, crystallized, aromatic polycarbon-
ate produced by solid-state condensation polymeriza-
tion (hereinafter, frequently referred to simply as
"solid-state polymerization") of each of the above-
21 7 00 19
24
mentioned prepolymers having molar ratios of the
terminal groups within the above-mentioned different
ranges, generally has, as terminal groups, both
hydroxyl groups and aryl carbonate groups. However,
if desired, it is possible that the molar ratio of
the terminal groups of the prepolymer is appropri-
ately changed so as to produce an aromatic poly-
carbonate having, as terminal groups, hydroxyl groups
only or aryl carbonate groups only.
Further, the prepolymer may also contain other
terminal groups, for example ethyl carbonate groups,
in addition to the terminal hydroxyl and aryl
carbonate groups, as described later. In such a
case, the above-mentioned ratio of the terminal
groups is represented by the molar ratio of the
total of the hydroxyl groups and other terminal
groups (e. g., ethyl carbonate groups) to the aryl
carbonate groups.
Aromatic group Ar of the recurring aromatic
carbonate units is preferably a divalent aromatic
group represented by, for example, formula (VI):
-Ark-Y-Ar2- (VI),
wherein each of Ark and Ar2 independently
represents a divalent carbocyclic or hetero-
cyclic aromatic group having from 5 to 30
21 7 00 19
carbon atoms, and Y represents a divalent
alkane group having from 1 to 30 carbon atoms.
Each of divalent aromatic groups Ar1 and Ar2 is
either unsubstituted or substituted with at least
5 one substituent which does not adversely affect the
solid-state polymerization reaction. Examples of
suitable substituents include a halogen atom, an
alkyl group having from 1 to 10 carbon atoms, an
alkoxy group having from 1 to 10 carbon atoms, a
10 phenyl group, a phenoxy group, a vinyl group, a
cyano group, an ester group, an amide group and a
nitro group.
As the heterocyclic aromatic group, as used
throughout this disclosure, aromatic groups having
15 one or more ring nitrogen atoms, oxygen atoms or
sulfur atoms may be mentioned.
Representative examples of divalent aromatic
groups include a phenylene group, a naphthylene
group, a biphenylene group and a pyridylene group,
20 each of which is unsubstituted or substituted with
at least one substituent, as mentioned above.
Representative examples of divalent alkane
groups include organic groups represented by the
formulae:
2170019
26
R1 R1 R3
I ~ I
-C--, ~ and C-
> C (CH -C-
)
2 k
R2 R2 R4
wherein each of R1, R2, R3 and R4 independently
represents a hydrogen atom, an alkyl group
having from 1 to 10 carbon atoms, an alkoxy
group having from 1 to 10 carbon atoms, a
cycloalkyl group having from 5 to 10 ring
carbon atoms, a carbocyclic aromatic group
having from 5 to 10 ring carbon atoms or a
carbocyclic aralkyl group having from 6 to 10
carbon atoms, and k represents an integer of
from 3 to 11, inclusive.
Preferred examples of divalent aromatic groups
include those of the formulae:
(R5)m ( )n (R5)m ( e)n
~CH ~CH~
CH3
H3 (Rs)n (R5)m CH3
C ~ , ~C ,
CH3
21'7 00 19.
27
(Rs)m B)n (Rs)m ( )n
C ~ CH
CF3
(Rs)m ~ ( s)n (Rs)m ~ ( )n
cH ~ C ~ and
CFa
(RS)m (~)n
CHI--EHy
wherein each of RS and R6 independently repre-
sents a hydrogen atom, a halogen atom, an alkyl
group having from 1 to 10 carbon atoms, an
alkoxy group having from 1 to 10 carbon atoms,
a cycloalkyl group having from 5 to 10 ring
carbon atoms or a phenyl group; each of m and n
independently represents an integer of from 1
to 4; when m is an integer of from 2 to 4, each
RS may be the same or different; and when n is
an integer of from 2 to 4, each R6 may be the
f 2~ ~ 00 ~ 9
28
same or different.
Divalent aromatic group Ar may contain a
divalent aromatic group represented by formula
(VII):
-Ar1-Z-Ar2- (VII)
wherein Ar1 and Ar2 are as defined above and Z
represents a bond, or a divalent group, such as
-O-, -CO-, -S-, -SO-, -S02-, -COO-, and
-CON(R1)-, wherein R1 is as defined above,
in an amount of 0 to 15 mole %, based on the total
number of moles of all of Ar's.
Examples of such divalent aromatic groups
include those of the formulae:
( 5)m (R6)n ( 5)m (R6)n
2 0 ( 5)m (R6)n ( 5)m (R6)n
U . U S U
( 5)m (R6)n ( 5)m (R6)n
U , ~~
_217009
29
( 5)m (R6)n ( 5)m ~Rs)n
CONH ~ . ~ CO ~ ,
( 5)m CH3 (Rs)n p O ( 5)m CH3 ~R6)n
C CIO ~ 'O ,
CH3 ~ "H3
( 5)m (RS)m ~R6)n
and
wherein R5, R6, m and n have the same meanings
as defined above.
The prepolymer of the present invention may
contain, as Ar, one type of a divalent aromatic
group mentioned above. Alternatively, the prepoly-
mer may contain two or more different types of di-
valent aromatic groups.
The most preferred is a prepolymer containing
an unsubstituted or substituted bisphenol A group
represented by formula (VIII):
--- ~ 21 7 0 0 1 9
(R5)m CH3 (R6)n
~>---- C ---~-- ( V I I I )
I
CE13
5
in an amount of 85 to 100 mole %, based on the total
number of moles of all of Ar's.
The prepolymer may also contain a trivalent
aromatic group in an amount of about 0.01 to 3
10 mole %, based on the total number of moles of all of
Ar's.
Ar3 of the terminal aryl carbonate group is
either unsubstituted or substituted with at least
one substituent which does not adversely affect the
15 reaction. Examples of suitable substituents include
a halogen atom, an alkyl group having from 1 to 10
carbon atoms, an alkoxy group having from 1 to 10
carbon atoms, a phenyl group, a phenoxy group, a
vinyl group, a cyano group, an ester group, an amide
20 group and a nitro group.
Representative examples of monovalent aromatic
groups Ar3 include a phenyl group, a naphthyl group,
a biphenyl group and a pyridyl group, each of which
is unsubstituted or substituted with at least one
25 substituent, as mentioned above.
2170019
31
Representative examples of Ar3 include
iH3 CH3
-O ~ ~CE:3, -~-C-CH3, -~~-- C ---~p~ and
CII3 Cfl3
CH3 CH3
-~-C - CE12 - C -CE13 .
I
CH3 CH3
The porous, crystallized, aromatic polycarbon-
ate prepolymer of the present invention has a number
average molecular weight of from 1,000 to 15,000.
When the number average molecular weight is less
than 1,000, solid-state polymerization of the pre-
polymer disadvantageously takes a long period of
time. Further, the prepolymer is disadvantageously
fusion-bonded during the solid-state polymerization.
On the other hand, it is unnecessary for the pre-
polymer to have a number average molecular weight of
larger than 15,000, because the increase in number
average molecular weight of the prepolymer larger
than 15,000 does not have any special effect on the
rate of the solid-state polymerization of the pre-
polymer. More preferred number average molecular
weight is 1,500 to 13,000. The most preferred is a
2170019
32
number average molecular weight of 2,000 to 8,000.
The porous, crystallized, aromatic polycarbon-
ate prepolymer of the present invention has a
specific surface area of at least 0.2 m2/g. Such a
large specific surface area is important for produ-
cing an porous, crystallized, aromatic polycarbon-
ate. When the specific surface area is smaller than
0.2 m2/g, the rate of the solid-state polymerization
of the porous, crystallized, prepolymer is lowered,
which is disadvantageous for producing an aromatic
polycarbonate on a commercial scale. The larger the
specific surface area of the porous, crystallized,
aromatic polycarbonate prepolymer of the present
invention, the higher the rate of the solid-state
polymerization becomes, which is advantageous. From
this standpoint, the specific surface area of the
porous, crystallized, aromatic polycarbonate pre-
polymer of the present invention is at least
0.2 m2/g , preferably at least 0.5 m2/g, more
preferably at least 0.8 m2/g.
The specific surface area is measured by the
Brunauer-Emmett-Teller method (BET method) using a
krypton gas.
The desired specific surface area of the crys-
tallized prepolymer of the present invention, which
2170019
33
is as large as 0.2 m2/g or more, is attained by
solvent treatment for crystallizing and simultane-
ously rendering porous a prepolymer. The scanning
electron micrographs of Figs. 1, 2, 4, 5, 6, 7 and 8
clearly show that the prepolymer of the present
invention is porous. For comparison, a scanning
electron micrograph of an amorphous prepolymer which
has not been subjected to solvent treatment is shown
in Fig. 3, which shows that the amorphous prepolymer
is non-porous.
The porous, aromatic polycarbonate prepolymer
of the present invention is crystalline. The crys-
tallinity of the prepolymer is at least 5 % as
measured by X-ray diffractometry. When the crystal-
linity of the prepolymer is less than 5 %, it is
disadvantageous in that the prepolymer is likely to
be melted in the course of the solid-state polymeri-
zation for producing a final polycarbonate, causing
the solid-state polymerization to be difficult to
conduct. The upper limit of the crystallinity is
not specifically restricted. However, for subject-
ing the prepolymer to solid-state polymerization to
produce an aromatic polycarbonate, it is preferred
that the crystallinity be not greater than 55 % from
the standpoint of the rate of solid-state polymeri-
34 2 1 7 0 0 1 9
nation. For facilitating the solid-state polymeri-
nation, the crystallinity of the prepolymer is pre-
ferably 10 to 45 %, more preferably 15 to 40 %.
In the present invention, the crystallinity of
the porous, crystallized prepolymer is determined by
using the powder X-ray diffraction patterns of a
completely amorphous prepolymer and a porous, crys-
tallized prepolymer (for example, see Fig. 10 and
Fig. 11).
Generally, when a crystalline polymer is
irradiated with an X-ray, scattered X-rays are
observed. The total intensity of the scattered X-
rays is a sum of the X-ray intensity of the crystal-
line scattering ascribed to the crystalline portion
and that of the amorphous scattering ascribed to the
amorphous portion. When the weight of the crystal-
line portion and that of the amorphous portion are
expressed as Mc and Ma, respectively, and when the
X-ray intensity of the crystalline scattering cor-
responding to the weight of the crystalline portion
and that of the amorphous scattering corresponding
to the weight of the amorphous portion are expressed
as Ic and Ia, respectively, and Ic and Ia are as-
sumed to be able to be distinguished from each
other, the crystallinity Xc (%) is calculated from
2170019
the following equations:
Mc Ic
Xc = Mc + Ma x 100 - Ic + KIa x 100
K = I100c
I100a
5 wherein I100c represents the X-ray intensity of a
crystalline scattering per unit weight of the per-
fectly crystalline portion and I100a represents the
X-ray intensity of an amorphous scattering per unit
weight of the perfectly amorphous portion.
10 However, in the present invention, assuming
that.K = 1 with respect to all the porous, crystal-
lized prepolymers, the crystallinity Xc ($) was
calculated from the following equation:
I
15 Xc = I +cI x 100.
c a
The total X-ray diffraction intensity of a
sample obtained by X-ray diffractometry is obtained
as a sum of the crystalline scattering intensity,
the amorphous scattering intensity and the back-
20 ground intensity due to the scattering by air, the
scattering ascribed to the thermal motion of atoms,
the Compton scattering and the like. Therefore, for
obtaining the crystallinity of the sample, it is
necessary to separate the total X-ray diffraction
25 intensity into the component intensities mentioned
x.2170019
36
above.
In the present invention, the total X-ray dif-
fraction intensity is separated into the component
intensities as follows. An explanation is given
referring to Figs. 10 and 11.
On the powder X-ray diffraction pattern of a
porous, crystallized prepolymer (shown in Fig. 11),
straight line P-Q (base line) is drawn between the
point (P) of 10°(28) and the point (Q) of 35°(28).
The point corresponding to 15°(2A) on the diffrac-
tion intensity curve and the point corresponding to
15°(2A) on the base line, at each of which points
the crystalline scattering intensity is considered
to be zero, are designated R and S, respectively.
On the other hand, on the powder X-ray diffrac-
tion pattern of a completely amorphous prepolymer
(shown in Fig. 10) (obtained by melting the prepoly-
mer at a temperature of from 280 to 300 °C, shaping
the molten prepolymer into a sheet form having a
thickness of about 1 mm, and rapidly cooling the
sheet to 0 °C), straight line K-L (base line) is
drawn. Further, the point corresponding to 15°(2A)
on the diffraction intensity curve and the point
corresponding to 15°(2A) on the base line are de-
signated M and N, respectively.
2170019
37
The following identities are given:
I1 - the diffraction intensity at point M
B1 - the diffraction intensity at point N
I2 - the diffraction intensity at point R
B2 - the diffraction intensity at point S
Y - the area of the portion surrounded by
diffraction intensity curve R-M-L and
straight line K-L, and
Z - the area of the portion surrounded by
diffraction intensity curve P-R-Q and
straight line P-Q.
The crystallinity Xc (%) is calculated from the
following equation:
Xc (%) - Z (Z - I2 = B2 .Y) x 100.
1 1
The porous, crystallized, aromatic polycarbon-
ate prepolymer of the present invention is, general-
ly, in powder form or in agglomerated powder form.
The powder form of porous, crystallized, aromatic
polycarbonate prepolymer has an average particle
diameter of not greater than 250 um. The agglomer-
ated powder form of porous, crystallized, aromatic
polycarbonate prepolymer has an average diameter of
not greater than 3 mm. In this connection, it
should be noted that when a powder or agglomerated
z~ goo ~~
38
powder form of a porous, crystallized, aromatic
polycarbonate prepolymer is subjected to solid-state
polymerization, it is preferred that the content of
too fine particles in the prepolymer be as small as
possible from the standpoint of ease in handling.
Further, when the amount of fine particles present
in the powder form or agglomerated powder form of
the prepolymer is large, it is disadvantageous in
that the particles of both the prepolymer and the
formed polymer are likely to be fused and bonded
with one another or adhered to a reaction vessel in
the course of the solid-state polymerization. From
these standpoints, it is preferred that the content
of particles having a particle diameter as small as
50 um or less in the prepolymer be not greater than
10 % by weight.
According to the present invention, from the
viewpoint of ease in handling, it is preferred that
the porous, crystallized, aromatic polycarbonate
prepolymer be in granular form. It is more prefer-
red that the granular form of porous, crystallized,
aromatic polycarbonate prepolymer have a compressive
break strength of at least 5 kgf/cm2. When the
compressive break strength is lower than 5 kgf/cm2,
it is disadvantageous in that too fine particles are
21 7 00 19
39
formed before and during the solid-state polymeriza-
tion, causing the handling of prepolymer to be dif-
ficult. It is preferred that the compressive break
strength be as large as possible. However, in
general, it is sufficient for the granular form of
prepolymer to have a compressive break strength of
at least 5 kgf/cm2.
It is most preferred that the above-mentioned
granular form of prepolymer have a crystallinity of
at least 5 %, preferably not greater than 55 % (X-
ray diffractometry). These granular form of the
porous, crystallized prepolymer is advantageous not
only in that the handling of the prepolymer before
and of ter the solid-state polymerization is easy;
the scattering of a powdery prepolymer is avoided
when the prepolymer is subjected to solid-state
polymerization; and the prepolymer is not fused
during the solid-state polymerization, but also in
that the rate of the solid-state polymerization can
be markedly increased.
The shape of the granular form of prepolymer is
not specifically restricted, and it may generally be
a pellet, sphere, cylinder, disc, polygonal pillar,
cube, rectangular parallelepiped, lens or the like.
21 7 00 19
The average diameter of granules of the
granular form of prepolymer may generally be 0.5 to
30 mm, preferably 0.8 to 10 mm, more preferably 1 to
5 mm. When the average particle diameter is smaller
5 than 0.5 mm, it is disadvantageous in that the fine
particles of the prepolymer scatters and the pre-
polymer is likely to be fused. On the other hand,
the granular form of prepolymer having an average
diameter of greater than 30 mm is not preferred from
10 the standpoint of ease in handling.
In the present invention, the diameter of
granules of the granular form of prepolymer is
defined as the volume average diameter defined in
"Zoryu-Binran (Granulation Handbook)", edited by the
15 Society of Powder Industry in Japan, published in
1975, pp. 19-20. Illustratively stated, the volume
average diameter is defined by the following
formula:
Volume average diameter = 3Lwh/(Lw+wh+hL),
20 wherein w is the short axis diameter (which is
defined as the distance between a pair of parallel
lines which is the smallest among the distances
between any pair of parallel lines drawn so as to
hold therebetween the projected image of a granule
25 on a plane, which granule is stably put on the
_2170019
41
plane), L is the long axis diameter [which is
defined as the distance between a pair or parallel
lines (which are perpendicular to the pair of paral-
lel lines used for defining the short axis diameter)
drawn so as to hold therebetween the projected image
of the granule), and h is the height of the granular
form of prepoly~ner.
In another aspect of the present invention,
there is provided a method for producing a powder
form of porous, crystallized, aromatic polycarbonate
prepolymer, which comprises treating an amorphous
aromatic polycarbonate prepolymer with solvent under
sufficient shearing force to crystallize and render
porous the amorphous aromatic polycarbonate pre-
polymer,
the amorphous aromatic polycarbonate prepolymer
comprising recurring carbonate units and terminal
hydroxyl and aryl carbonate groups, wherein the
molar ratio of the terminal hydroxyl groups to the
terminal aryl carbonate groups is from 5/95 to 95/5,
and having a number average molecular weight of
1,000 to 15,000,
the shearing force being sufficient to cause
the resultant powdery, porous, crystallized,
aromatic polycarbonate prepolymer to have an average
2170019
42
particle diameter of 250 um or less.
The amorphous aromatic carbonate prepolymer
comprising recurring carbonate groups and having
terminal hydroxyl and aryl carbonate groups, and
having a number average molecular weight of 1,000 to
15,000, which is used as a starting material, may
generally be prepared by pre-polymerization as will
be described later. Then, the amorphous prepolymer
is treated with solvent under a high shearing force
sufficient to reduce the prepolymer to particles
having an average particle diameter of 250 um or
less, to thereby crystallize and simultaneously
render porous the amorphous prepolymer. In this
method, the amorphous prepolymer to be treated with
solvent may be either in the solid state or in the
molten state. The crystallization and pore forma-
tion of the amorphous prepolymer occur from its
surface. Therefore, for obtaining a porous, crys-
tallized prepolymer of the present invention having
a specific surface area of at least 0.2 m2/g, it is
necessary that the treatment of the prepolymer with
solvent be conducted while mechanically pulverizing
the prepolymer under high shearing force to the
prepolymer so as to reduce the prepolymer to
particles having an average particle diameter of
21 7 00 19
43
250 um or less. The average particle diameter used
herein means that of the prepolymer in the solvent
which is determined by a method as will be described
later. The mechanical pulverization under high
shearing force may easily be conducted by a method
using an apparatus equipped with a high speed-rotat-
ing blade, such as a warning blender, or using a
centrifugal pump equipped with a cutter. For
shortening the time required for the crystallization
and pore formation, it is preferred that the amor-
phous prepolymer to be treated with solvent be in
the form of a fiber, a strand, a film, beads or the
like, irrespective of the state of the amorphous
prepolymer, that is, the solid state or the molten
state.
The time required for crystallizing and render-
ing porous an amorphous prepolymer in solvent is
varied according to the type, molecular weight and
shape of the amorphous prepolymer, the type of the
solvent, the treating temperature and the like.
Generally, the crystallization and pore formation
may be accomplished within several seconds to
several hours. The temperature may generally be
chosen in the range of from -10 to 200 °C. From
the standpoints of the crystallization rate and
217009
44
ease in obtaining a porous, crystallized, aromatic
polycarbonate prepolymer having a large specific
surface area, it is preferred that the crystalliza-
tion be conducted at a temperature as high as pos-
Bible within the above-mentioned range.
Representative examples of solvents which can
be used for crystallizing and rendering porous the
amorphous prepolymer include halogenated aliphatic
hydrocarbons, such as methyl chloride, methylene
chloride, chloroform, tetrachloromethane, ethyl
chloride, dichloroethanes (all position isomers),
trichloroethanes (all position isomers), trichloro-
ethylene and tetrachloroethanes (all position
isomers); halogenated aromatic hydrocarbons, such as
chlorobenzene and dichlorobenzene; ethers, such as
tetrahydrofuran and dioxane; ketones, such as
acetone and methylethylketone; aromatic hydro-
carbons, such as benzene, toluene and xylene; and
the like. These solvents may be used individually
or in combination. Of these, acetone is most
preferred because it is effective for obtaining a
porous, crystallized, aromatic polycarbonate pre-
polymer having a relatively large specific surface
area.
The amount of the solvent to be used for crys-
2170019
tallizing and rendering porous the amorphous pre-
polymer is varied according to the types of the
amorphous prepolymer and solvent, the desired crys-
tallinity and desired specific surface area of the
5 ultimate prepolymer, the crystallizing temperature,
and the like. Generally, the solvent may be used in
an amount of 0.1 to 100 times, preferably 0.3 to 50
times the weight of the amorphous prepolymer.
By the above-mentioned method, a powder form of
10 porous, crystallized, aromatic polycarbonate pre-
polymer having the desired crystallinity and the
desired specific surface area is obtained. Some-
times, the thus obtained powder form of prepolymer
contains too fine particles. For reducing the
15 amount of too fine particles, it is preferred that
particles (primary particles) of the powder form of
prepolymer be subjected to agglomeration to form
secondary particles. Thus, the porous, crystal-
lized, aromatic polycarbonate prepolymer is obtained
20 in agglomerated powder form (secondary particle
form).
Accordingly, in a further aspect of the present
invention, there is provided a method for producing
an agglomerated powder form of porous, crystallized,
25 aromatic polycarbonate prepolymer, which comprises
217Q019
46
applying sufficient pressure or heat to particles of
a powder form of porous, crystallized, aromatic
polycarbonate prepolymer mentioned above, to cause
the particles to be cohered.
The application of sufficient pressure to
particles of a powder form of porous, crystallized,
aromatic polycarbonate prepolymer may advantageously
be conducted simultaneously with the removal of the
solvent used for crystallizing and rendering porous
the amorphous prepolymer after completion of the
crystallization and pore formation. Illustratively
stated, the solvent is generally removed by centri-
fugation, filtration under pressure, filtration
under reduced pressure, or the like, by which a
pressure is applied to the prepolymer simultaneous-
ly. This pressure is sufficient for the agglomeration
of a powder, i.e., secondary particle formation.
Therefore, agglomeration of a powder of prepolymer
can advantageously be performed simultaneously with
the removal of the solvent. The thus formed
secondary particle (agglomerated powder form) of the
prepolymer is stable, and hardly to be reduced to
too minute particles even after the solvent is com-
pletely removed from the prepolymer. The reason for
this has not yet been elucidated, but it is believed
21 7 00'(9
47
that a low molecular weight polycarbonate oligomer
present in the prepolymer acts as an adhesive for
bonding too minute particles. In view of the above,
when the amorphous prepolymer contains a low mole-
cular polycarbonate oligomer in an extremely small
amount, it is preferred that a low molecular weight
polycarbonate oligomer be added to the amorphous
prepolymer before the crystallization and pore
formation be conducted.
Agglomeration for forming secondary particles
may also be conducted utilizing the fusion-bonding
property of the powder form of prepolymer. That is,
a powder form of prepolymer is sufficiently heated
to such a temperature that the surfaces of the
particles of the prepolymer are fused slightly, to
thereby agglomerate the powder.
In the above-mentioned method, a powder form of
porous, crystallized, aromatic polycarbonate pre-
polymer to be used as a starting material for
roducin an a lomerated form of
P g gg prepolymer has a
specific surface area of at least 0.2 m2/g, prefer-
ably at least 0.5 m2/g. The crystallinity of the
powder form of prepolymer is at least 5 %, prefer-
ably not greater than 55 %.
The thus obtained powder or agglomerated powder
2170019
48
form of porous, crystallized, aromatic polycarbonate
prepolymer may be granulated to produce a granular
form of porous, crystallized, aromatic polycarbonate
prepolymer mentioned above. Thus, in still a
further aspect of the present invention, there is
provided a method for producing a granular form of
porous, crystallized, aromatic polycarbonate pre-
polymer, which comprises granulating a powder form
or an agglomerated powder form of porous, crystal-
lized, aromatic polycarbonate prepolymer.
The method for granulating the powder or agglo-
merated powder form of prepolymer is not specifical-
ly restricted. Generally, granulation of the pre-
polymer can easily be performed by a conventional
method, such as a rolling method, a vibration
method, a compression molding method and an extru-
sion molding method. Of these methods, extrusion-
granulation by an extrusion molding method and com-
pression-granulation by a compression molding method
are most preferred, because a granular shaped
article of the present invention having a compres-
sive break strength of at least 5 kgf/cm2 can easily
be produced. The granulation can advantageously be
performed, using a commercially available tablet
machine or granulator, at a temperature of not
21~~O~g
49
greater than the crystalline melting point of the
prepolymer, preferably 0 to 100 °C.
Production of a granular form of prepolymer may
be conducted in dry state using a dry powder form or
a dry agglomerated powder form of porous, crystal-
lized prepolymer, or in wet state using a powder form
or an agglomerated powder form of prepolymer wetted
with an appropriate liquid. Preferred is the wet
state method, because a powder form or an agglom-
erated powder form of prepolymer produced by the
crystallization and pore formation can be subjected
to granulation without completely removing the
solvent therefrom.
The above-mentioned porous, crystallized,
aromatic polycarbonate prepolymers in powder form,
agglomerated powder form and granular form can
advantageously be used as prepolymers to be
subjected to solid-state condensation polymeriza-
tion, to thereby produce porous, crystallized,
aromatic polycarbonates. From the powder form or the
agglomerated powderform of prepolymer, a powder form
or an agglomerated powder form of porous, crystal-
lized, aromatic polycarbonate is produced. On the
other hand, from the granular form of prepolymer, a
granular form of porous, crystallized, aromatic
2170019
0 ~. ~ , .. ..
polycarbonate is produced.
Hereinbelow, an explanation is given with
respect to the production of a powder form or an
agglomerated powder form of porous, crystallized,
5 aromatic polycarbonate. That is, according to the
present invention, there is provided a method for
producing a powder form or an agglomerated powder
form of porous, crystallized, aromatic polycarbonate
having a number average molecular weight of from
6,000 to 200,000 and a crystallinity of at least
35 $, which comprises heating a powder form or an
agglomerated powder form of porous, crystallized,
aromatic polycarbonate prepolymer in a heating zone,
at a temperature which is higher than the glass
transition temperature of the prepolymer and at
which the prepolymer is in a solid state, to effect
solid-state condensation polymerization of the pre-
polymer while removing condensation polymerization
by-products from the heating zone,
thereby increasing the number average molecular
weight and the crystallinity of the prepolymer to
from 6,000 to 200,000 and at least 35 $, respective-
ly, so that the resultant polycarbonate has a number
average molecular weight and a crystallinity which
are, respectively, greater than those of the pre-
E 2170019
51
polymer.
In the above method, it is more preferred that
the porous, crystallized, aromatic carbonate prepoly-
mer to be subjected to solid-state polymerization
have a specific surface area of at least 0.5 m2/g.
Further, it is preferred that the porous, crystal-
lized aromatic carbonate prepolymer have a crystal-
linity of from 5 to 55 $.
The solid-state polymerization in the method of
the present invention is conducted by heating a
powder form or an agglomerated powder form of
porous, crystallized, aromatic polycarbonate pre-
polymer in a heating zone. The temperature (Tp, °C)
and time required for the solid-state polymerization
vary depending upon the chemical structure, molec-
ular weight, crystallinity, melting point (Tm, °C)
and shape of the porous, crystallized, aromatic
polycarbonate prepolymer; the presence or absence of
a catalyst remaining in the porous, crystallized,
aromatic polycarbonate prepolymer; the type and
amount of a catalyst, if any, in the porous, crys-
tallized, aromatic polycarbonate prepolymer; the
type and amount of a catalyst if added to the poly-
merization system; the specific surface area of the
porous, crystallized, aromatic polycarbonate pre-
21 7 00 ~ 9
52
polymer; the polymerization degree of the desired
crystallized, aromatic polycarbonate; and the like.
But, the solid-state polymerization must be
conducted at a temperature which is higher than the
glass transition temperature of the porous, crys-
tallized prepolymer and at which the porous, crys-
tallized, aromatic polycarbonate prepolymer is not
melted but in a solid state (namely, a temperature
of lower than the crystalline melting temperature of
the prepolymer). It is more preferred that the
solid-state polymerization be conducted at a tem-
perature (Tp, °C) satisfying the following relation-
ships:
Tm - 5 0 < Tp < Tm ( V )
wherein Tp and Tm are as defined above.
In this connection, it is to be noted that both the
glass transition temperature and the crystalline
melting temperature of the prepolymer are elevated
with the progress of the polymerization of the pre-
polymer. Therefore, the suitable temperature for
solid-state polymerization also becomes high with the
progress of the polymerization. The reaction time
for solid-state polymerization is generally in the
range of from one minute to 100 hours, preferably in
the range of from 0.1 to 50 hours. With respect to
s 2170019
53
the temperature for solid-state polymerization, for
example, when a polycarbonate is prepared from bis-
phenol A, the temperature for the solid-state poly-
merization is in the range of from about 150° to
about 260 °C, preferably from about i80° to about
230 °C.
In the solid-state condensation polymerization,
condensation polymerization by-products, such as an
aromatic monohydroxyl compound and a diaryl carbon-
ate, are formed in the heating zone. The solid-
state condensation polymerization reaction may be
accelerated by removing the by-products from the
polymerization reaction system. The by-products may
be removed by a method in which the polymerization
reaction is carried out under reduced pressure, or a
method in which an inert gas is flowed into the
heating zone and the inert gas containing the
condensation polymerization by-products is dis-
charged from the heating zone. The term "inert gas"
used herein means not only those defined by the so-
called inert gas as an established term, such as
nitrogen gas, argon gas, helium gas and carbon
dioxide gas, but also a gas which is not reactive
during the solid-state polymerization, such as lower
hydrocarbon gas and acetone gas. These methods are
2170019
54
optionally conducted in combination. In the method
using an inert gas, it is preferred to heat the gas
preliminarily to a temperature adjacent the poly-
merization reaction temperature. The flow rate of
the inert gas flowing into the heating zone may
generally be from 0.1 to 10 liters(N.T.P.)/hour,
preferably from 0.2 to 7 liters(N.T.P.)/hour, per
gram of the porous, crystallized, aromatic polycar-
bonate prepolymer. The flow rate of the inert gas
per unit weight of the prepolymer is important.
When the flow rate of the inert gas is less than 0.1
liter(N.T.P.)/hour per gram of the prepolymer, it is
disadvantageous in that the rate of the solid-state
polymerization becomes low. On the other hand, when
the flow rate of the inert gas is greater than 10
liters(N.T.P.)/hour per gram of the prepolymer,
although the rate of the solid-state polymerization
becomes high, the powder form or agglomerated powder
form of porous, crystallized, aromatic carbonate
prepolymer is, disadvantageously, likely to scatter
in the reaction vessel during the solid-state con-
densation polymerization, leading to a fusion-
adhesion of the prepolymer to the wall of the reac-
tion vessel and an escape of the prepolymer out of
the reaction vessel.
_2170019
When the solid-state polymerization is
conducted while flowing an inert gas into the heat-
ing zone, the discharged inert gas may be discarded
without the re-use thereof. Alternatively, in order
5 to reduce the production cost, the discharged inert
gas may be recovered and re-used. The discharged
inert gas contains condensation polymerization by-
products mentioned above, such as an aromatic mono-
hydroxyl compound and a diaryl carbonate. There-
10 fore, it has been considered that when the dis-
charged inert gas is recovered and re-used, it is
necessary to remove the by-products contained in the
inert gas. However, it has unexpectedly been found
that even if the inert gas contains the by-products,
15 when the content of the condensation polymerization
by-products of the discharged inert gas is 5 mmHg or
less in terms of the partial pressure of the by-
products in the inert gas, such an inert gas
containing the by-products can be re-used for the
20 solid-state condensation polymerization of the pre-
polymer, and the condensation polymerization can
advantageously be performed. Therefore, in the
method of the present invention, the discharged
inert gas having a by-products content of 5 mmHg or
25 less in terms of the partial pressure of the by-
__ 2170019
56
products in the inert gas may advantageously be
flowed into the heating zone as the inert gas and
re-used for the solid-state polymerization. Of
course, from the standpoint of complete avoidance of
the adverse reaction during the solid-state poly-
merization, it is most preferred that the by-
products be completely removed from the discharged
inert gas. However, it is extremely difficult to
remove the by-products from the discharged inert gas
to an extent that the content of the by-products in
the discharged inert gas is less than 0.01 mmHg in
terms of the partial pressure. The reduction of the
by-products content in the inert gas may generally
be conducted by removing the by-products from the
discharged inert gas or by diluting the discharged
inert gas with a fresh inert gas.
The solid-state polymerization according to the
method of the present invention may be carried out
by using a batch-wise method or a continuous method,
or by using both methods in combination. As a
reactor for the solid-state condensation polymeriza-
tion, various types of reactors, for example, a
tumbler type, a kiln type, a paddle-dryer type, a
screw-conveyer type, a vibrator type, a fluidized-
bed type, a fixed-bed type, a moving bed type and
2170019
57
the like can be used.
The solid-state condensation polymerization for
producing the porous, crystallized, aromatic poly-
carbonate from the porous, crystallized prepolymer
may be performed at an economically satisfactory
reaction rate without using a catalyst. This is the
most preferred mode of the present method. Alterna-
tively, a catalyst may be added in order to accel-
erate the polymerization reaction rate. However,
when a catalyst is used, such a catalyst is likely
to remain in the final aromatic polycarbonate as an
impurity and such a impurity catalyst often has
adverse effects on the physical properties of the
aromatic polycarbonate (such as color, heat resis-
tance, boiled water resistance and weatherability~.
Therefore, it is preferred that the amount of a
catalyst to be used be as small as possible.
When the porous, crystallized, aromatic poly-
carbonate prepolymer of the present invention to be
used as a starting material for producing a porous,
crystallized, aromatic polycarbonate is produced
using a catalyst, the.catalyst generally remains in
the prepolymer and, therefore, a further catalyst
need not be added to the solid-state polymerization
system. However, in the case where the catalyst is
21 7 00 19
58
removed or inactivated in the course of the crystal-
lization and pore formation of the prepolymer and it
is still desired to accelerate the solid-state poly-
merization, an appropriate catalyst may optionally
be added to the solid-state polymerization reaction
system. In this case, a catalyst may be added in a
liquid or gas form to a polymerization system of the
porous, crystallized prepolymer. As such a cata-
lyst, any condensation polymerization catalyst
conventionarily used in the art can be used. Exam-
ples of such catalysts include hydroxides of an
alkali or alkaline earth metal, such as lithium
hydroxide, sodium hydroxide, potassium hydroxide and
calcium hydroxide; hydrides of an alkali or alkaline
earth metal, such as lithium hydride, sodium hydride
and calcium hydride; alkali metal salts, alkaline
earth metal salts and quarternary ammonium salts of
boron hydride or aluminum hydride, such as lithium
aluminum hydride, sodium boron hydride and tetra-
methyl ammonium boron hydride; alkoxides of an
alkali or alkaline earth metal, such as lithium
methoxide, sodium ethoxide and calcium methoxide;
aryloxides of an alkali or alkaline earth metal,
such as lithium phenoxide, sodium phenoxide, magne-
sium phenoxide, Li0-Ar-OLi wherein Ar is an aryl
2170019
59
group and Na0-Ar-ONa wherein Ar is as defined above;
organic acid salts of an alkali or alkaline earth
metal, such as lithium acetate, calcium acetate and
sodium benzoate; zinc compounds, such as zinc oxide,
zinc acetate and zinc phenoxide; boron compounds,
such as boron oxide, boric acid, sodium borate,
trimethyl borate, tributyl borate and triphenyl
borate; silicon compounds, such as silicon oxide,
sodium silicate, tetraalkylsilicon, tetraarylsilicon
and diphenyl-ethyl-ethoxysilicon; germanium com-
pounds, such as germanium oxide, germanium tetra-
chloride, germanium ethoxide and germanium phen-
oxide; tin compounds, such as tin oxide, dialkyltin
oxide, diaryltin oxide, dialkyltin carboxylate, tin
acetate, tin compounds having an alkoxy group or
aryloxy group bonded to tin, such as ethyltin tri-
butoxide and organotin compounds; lead compounds,
such as lead oxide, lead acetate, lead carbonate,
basic lead carbonate, and alkoxides and aryloxides
of lead or organolead; onium compounds, such as a
quaternary ammonium salt, a quaternary phosphonium
salt and a quaternary.arsonium salt; antimony com-
pounds, such as antimony oxide and antimony acetate;
manganese compounds, such as manganese acetate,
manganese carbonate and manganese borate; titanium
21 7 00 qg
compounds, such as titanium oxide and titanium alko-
xides and titanium aryloxides; and zirconium com-
pounds, such as zirconium acetate, zirconium oxide,
zirconium alkoxides and zirconium aryloxides and
5 zirconium acetylacetone.
These catalysts may be used individually or in
combination. The amount of catalyst to be used is
as follows. When a catalyst containing a metal is
used, the amount of the catalyst is generally in the
10 range of from 1 ppm to 500 ppm by weight, in terms
of the amount of the metal contained in the cata-
lyst, based on the weight of the porous, crystal-
lazed, aromatic polycarbonate prepolymer used as the
starting material. When a catalyst containing no
15 metal is used, the amount of the catalyst is gener-
ally in the range of from 1 ppm to 500 ppm by
weight, in terms of the amount of the atom as a
canon species contained in the catalyst, based on
the weight of the prepolymer.
20 As mentioned above, in the method of the
present invention, the intended prepolymer can
readily be prepared in the absence of any catalyst,
and the aromatic polycarbonate produced without
using a catalyst has an extremely excellent proper-
25 ties. This is one of the main features of the
21 7 pp ~ g
61
present invention. In the present invention, the
terminology "in the absence of a catalyst" means
that the amount of a catalyst is smaller than 1 ppm
that is the minimum in the above-mentioned amount
range.
According to the above-mentioned method of the
present invention, a powder form or an agglomerated
powder form of porous, crystallized, aromatic poly-
carbonate having a number average molecular weight
of from 6,000 to 200,000 and a crystallinity of at
least 35 %, wherein the number average molecular
weight and crystallinity of the aromatic polycarbon-
ate are greater than those of the porous, crystal-
lized prepolymer used as a starting material, can
easily be produced.
Further, according to the method of the present
invention, a powder form or an agglomerated powder
form of porous, crystallized, aromatic polycarbonate
having a specific surface area of at least 0.1 m2/g
can advantageously be produced.
Furthermore, according to the method of the
present invention, a powder form or an agglomerated
powder form of porous, crystallized, aromatic poly-
carbonate having a crystallinity of not greater than
70 %, which is greater than that of the prepolymer
2170019
62
used as a starting material, can easily be obtained.
Next, an explanation is given with respect to
the production of a granular form of porous, crys-
tallized, aromatic polycarbonate. That is, accord-
ing to the present invention, there is provided a
method for producing a granular form of porous,
crystallized, aromatic polycarbonate having a number
average molecular weight of from 6,000 to 200,000
and a crystallinity of at least 35 %, which
comprises heating a granular form of porous, crys-
tallized, aromatic polycarbonate prepolymer in a
heating zone, at a temperature which is higher than
the glass transition temperature of said prepolymer
and at which said prepolymer is in a solid state, to
effect solid-state condensation polymerization of
said prepolymer while removing condensation poly-
merization by-products from the heating zone,
thereby increasing the number average molecular
weight and the crystallinity of the prepolymer to
from 6,000 to 200,000 and at least 35 %, respective-
ly, so that the resultant polycarbonate has a number
average molecular weight and a crystallinity which
are, respectively, greater than those of said
granular prepolymer.
The heating of granular form of porous, crys-
~_ 21 7 00 19
63
tallized, aromatic polycarbonate prepolymer can be
conducted in substantially the same manner as in the
production of the powder form or the agglomerated
powder form of polycarbonate mentioned above, except
that a granular form of porous, crystallized,
aromatic polycarbonate prepolymer is used as a
starting material. In practicing the above-
mentioned method, it is preferred that the heating
of the granular form of prepolymer be conducted
while flowing an inert gas into the heating zone and
while discharging the inert gas containing the
condensation polymerization by-products from the
heating zone. The flow rate of the inert gas may
generally be in the range of from 0.1 to 50
liters(N.T.P.)/hour, per gram of the granular form
of prepolymer. In the case of the solid-state
polymerization of the granular form of prepolymer,
there is no problem of the scattering of the
prepolymer. Therefore, the flow rate of the inert
gas can be increased up to 50 liters(N.T.P.)/hour,
per gram of the granular form of prepolymer. The
rate of the solid-state polymerization. can be
increased by increasing the flow rate of the inert
gas. However, even when the flow rate of the inert
gas is increased to higher than 50 liters(N.T.P.)
2~ 7 00 19'
64
/hour, per gram of the granular form of prepolymer,
the rate of the solid-state polymerization is no
longer increased. Therefore, it is not necessary
that the flow rate of the inert gas be increased to
higher than 50 liters(N.T.P.)/hour, per gram of the
granular form of prepolymer. From the standpoint of
the improvement of the polymerization degree, the
flow rate of the inert gas is preferably in the
range of from 0.2 to 30 liters (N.T.P.)/hour, per
gram of the granular form of prepolymer.
As in the case of the production of a powder
form or an agglomerated powder form of polycarbon-
ate, it is preferred that the condensation polymeri-
zation by-products be removed from the discharged
inert gas, or the discharged inert gas be diluted
with an inert gas, so that the resultant gas has a
condensation polymerization by-products content of
5 mmHg or less in terms of the partial pressure of
the condensation polymerization by-products in the
inert gas, and the resultant gas be flowed into the
heating zone as the inert gas.
The granular form of porous, crystallized,
aromatic polycarbonate produced by the above-
mentioned method of the present invention comprises
terminal hydroxyl groups and/or terminal aryl
21 7 pp 19
carbonate groups, and has a number average molecular
weight of from 6,000 to 200,000 and a crystallinity
of from 35 to 70 $, which are, respectively, greater
than those of the granular form of prepolymer. In
5 this connection, it is preferred that the crystal-
linity of the granular form of porous, crystallized,
aromatic polycarbonate be not greater than 70
Further, it is also preferred that the specific
surface area of the granular polycarbonate be at
10 least 0.1 m2/g.
The granular form of porous, crystallized,
aromatic polycarbonate thus produced from the
granular, prepolymer has a compressive break
strength of at least 10 kgf/cm2 which is greater
15 than that of the granular form of prepolymer. This
fact is unexpected and surprising. It has been
considered that the compressive break strength of
the granular form of polycarbonate is lower than
that of the granular form of prepolymer. That is,
20 it has been considered that the polymerization by-
products, such as phenols and diaryl carbonate, are
removed during the solid-state condensation poly-
merization, and by the removal of the by-products
contained in the prepolymer, voids would be likely
25 to be formed in the produced polycarbonate, which
2170019
66
would result in a decrease in mechanical strength of
the resultant polycarbonate.
The granular form of porous, crystallized,
aromatic polycarbonate has substantially the same
shape and diameter as those of the granular form of
porous, crystallized, aromatic polycarbonate pre-
polymer which is used as a starting material.
Therefore, the granular polycarbonate, generally,
has a shape of a pellet, sheet, disk, cylinder,
polygonal pillar, cube, rectangular parallelepiped
or sphere, and has a diameter of 0.5 to 30 mm.
The powder form, the agglomerated powder form
or the granular form of porous, crystallized,
aromatic polycarbonate comprising recurring aromatic
carbonate units and terminal hydroxyl and/or aryl
carbonate groups and having a specific surface area
of at least 0.1 m2/g, a number average molecular
weight of from 6,000 to 200,000 and a crystallinity
of at least 35 $, may be subjected to molding at a
temperature lower than the glass transition tempera-
ture of the polycarbonate, to thereby obtain a
shaped, porous, crystallized, aromatic polycarbon-
ate. The thus obtained shaped polycarbonate has a
bulk density of from 0.1 to 1.1 g/cm3 and a compres-
sive break strength of at least 10 kgf/cm2. There-
2170019
67
fore, according to the present invention, there is
provided a method for producing a shaped, porous,
crystallized aromatic polycarbonate having a bulk
density of from 0.1 to 1.1 g/cm3 and a compressive
break strength of at least 10 kgf/cm2, which com-
prises subjecting a powder form, an agglomerated
powder form or a granular form of porous, crystal-
lized aromatic polycarbonate to molding at a temper-
ature which is lower than the glass transition
temperature of the polycarbonate,
the powder form, the agglomerated form or the
granular form of porous, crystallized, aromatic
polycarbonate comprising recurring aromatic carbon-
ate units and terminal hydroxyl and/or aryl carbon-
ate groups and having a specific surface area of at
least 0.1 m2/g, a number average molecular weight of
from 6,000 to 200,000 and a crystallinity of at
least 35 %.
In the above-mentioned method of the present
invention, the molding of the porous, crystallized
aromatic polycarbonate may generally be conducted by
compression molding or by extrusion molding at a
temperature lower than glass transition temperature
of the polycarbonate.
The powder form or agglomerated powder form of
2~~0019
68
the porous, crystallized, aromatic polycarbonate of
the present invention is not hydrolyzed during the
molding, even when the polycarbonate is subjected to
molding without drying the polycarbonate before
molding. This is due to its extremely small equi-
librium moisture content which is ascribed to its
high crystallinity. Accordingly, the powder form or
the agglomerated powder form of porous, crystal-
lized, aromatic polycarbonate also can advantageous-
ly be subjected to conventional molding method, such
as rotational molding and sinter molding, to prepare
a shaped article.
A shaped polycarbonate can also be produced by
heating the porous, crystallized, aromatic poly-
carbonate of the present invention. That is,
according to the present invention, there is
provided a method for producing a shaped, porous,
crystallized aromatic polycarbonate having a bulk
density of from 0.1 to 1.1 g/cm3 and a compressive
break strength of at least 10 kgf/cm2, which com-
prises heating particles of a powder form or of an
agglomerated powder form of porous, crystallized
aromatic polycarbonate, or heating granules of a
granular form of porous, crystallized aromatic poly-
carbonate, at a temperature which is higher than the
21 7 ~0 19
69
glass transition temperature of the polycarbonate
and which is lower than the crystalline melting
temperature of the polycarbonate, to fuse and bond
the surfaces of the particles or of the granules,
the powder form, the agglomerated powder form
or the granular form of porous, crystallized
aromatic polycarbonate comprising recurring aromatic
carbonate units and terminal hydroxyl and/or aryl
carbonate groups and having a specific surface area
of at least 0.1 m2/g, a number average molecular
weight of from 6,000 to 200,000 and a crystallinity
of at least 35 $. In this method, the heating of the
particles of the powder form or the agglomerated
powder form of porous, crystallized aromatic poly-
carbonate or the heating of the granular form of
porous, crystallized aromatic polycarbonate is
conducted at a temperature which is higher than the
glass transition temperature of the polycarbonate
and which is lower than the crystalline melting
point of the polycarbonate. Generally, the heating
may be conducted at 160 to 250 °C under a compres-
sive load at 0.1 to 2 tf/cm2.
By the above mentioned method, a shaped article
having excellent properties as will be described
later can be obtained. Therefore, according to the
21 7 00 19
present invention, there is provided a shaped,
porous, crystallized aromatic polycarbonate compris-
ing recurring aromatic carbonate units and terminal
hydroxyl and/or aryl carbonate groups, and having a
5 number average molecular weight of from 6,000 to
200,000, a bulk density of from 0.1 to 1.1 g/cm3, a
crystallinity of at least 35 $ and a compressive
break strength of at least 10 kgf/cm2.
In this connection, it is preferred that the
10 shaped article have a specific surface area of at
least 0.1 m2/g. Further, it is also preferred that
the crystallinity of the shaped polycarbonate be not
greater than 70 $.
The shaped, porous, crystallized aromatic poly-
15 carbonate may be in any form, e.g., a shape of a
granule, pellet, sheet, disc, cylinder, polygonal
pillar, cube, rectangular parallelepiped or sphere.
Each of the powder form or agglomerated powder
form of porous, crystallized, aromatic polycarbon-
20 ate, the granular form of porous, crystallized,
aromatic polycarbonate and the shaped, porous, crys-
tallized, aromatic polycarbonate of the present
invention has a high, sharp crystalline melting
point as well as a high crystallinity. These
25 properties clearly distinguish the aromatic poly-
21 7 00 19
carbonate of the present invention and the shaped
article thereof from the aromatic polycarbonate
produced by the conventional phosgene process or
melt process (transesterification process) mentioned
hereinbefore. Such a high crystallinity of each of
the porous, crystallized aromatic polycarbonate and
the shaped article thereof of the present invention
is presumed to be ascribed to the re-arrangement of
the molecular chains of the porous, crystallized
prepolymer, which is caused during the solid-state
condensation polymerization. The crystalline melt-
ing point of the aromatic polycarbonate of the
present invention is determined, using 5 to 10 mg of
a polycarbonate sample, by means of a differential
scanning calorimeter (hereinafter referred to as
"DSC") in an atomosphere of an inert gas at a heat-
ing rate of 10 °C/min. For example, in the case of
the aromatic polycarbonate produced using bisphenol
A, the peak of the crystalline melting point is at
230°to 300 °C, and the half width of the peak of the
crystalline melting point is 3°to 8 °C.
The porous, crystallized, aromatic polycarbon-
ate of the present invention and the shaped article
produced therefrom, both of which have high crystal-
linity, is excellent in resistance to chemicals and
21 7 00 19
72
solvent as compared to the conventional amorphous
aromatic polycarbonate. Therefore, the crystallized
aromatic polycarbonate can advantageously be used as
a sintering material, filter, absorbent of a gas or
a liquid, wall covering material and heat insulating
material, and may have various shapes, for example,
a pellet, sheet, disk, cylinder, polygonal pillar
cube, rectangular pallalelepiped or sphere.
Following is a chart showing the relationships
between aromatic polycarbonate prepolymers and
polycarbonates produced therefrom.
'.2170019
73
____
I ro
I ~
~
, I
O n >. b~ u1
O.
N
vi
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n. ~ .-' .~'
ro ro
a o
.u N o
v
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I
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N ..
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~, x
ro u~
.-a
O v
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C
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I
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N
O
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v
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yd
p.
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,
tn -.i ~.~
____~ N C ro
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v v
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ro~rox ~
b C v ~'p
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vb o N a v
Nu
p. v .A A,
N I1 N.ri
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v1 .-i U U C a
In of E ,p
Il. E
i ' ro
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ro ro N
.., ~
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a~
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m ~n v
ro
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c
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ro
N
U
ro
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ro c~
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>
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. GI
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..~ ,.-~
v
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tr
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ro
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a. +~
-i rt1
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o. O
-- C
ro
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N
N
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td
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b~
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v~ ~~
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m~ U.~a,w
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L______!
_217009
74
Hereinbelow, an explanation is given with
respect to the preparation of an amorphous, aromatic
polycarbonate prepolymer which is used as a starting
material for producing a porous, crystallized,
aromatic polycarbonate prepolymer of the present
invention. The method for preparing the amorphous
prepolymer is not specifically restricted. General-
ly, the following methods may be used.
Method (1): a transesterification is performed
between an aromatic dihydroxyl compound and a diaryl
carbonate.
Method (2): an aromatic dihydroxy compound and
a diaryl carbonate are reacted with each other in a
molar ratio of from 1:1.2 to 1:2 to prepare an
aromatic polycarbonate oligomer containing terminal
groups comprised mainly of aryl carbonate groups and
having a number average molecular weight of about
350 to 950 and, then, a transesterification is per-
formed between the oligomer and an aromatic dihy-
droxy compound.
Method (3): an aromatic dihydroxy compound and
a diaryl carbonate are reacted with each other in a
molar ratio of from 1.2:1 to 2:1 to prepare an
aromatic polycarbonate oligomer containing terminal
groups comprised mainly of hydroxyl groups and having
a 2170019
a number average molecular weight of about 350 to 950
and, then, a transesterification is performed between
the oligomer and a diaryl carbonate.
Method (4): an aromatic dihydroxy compound and
5 phosgene are subjected to interfacial condensation
polymerization in the presence of a molecular weight
controller.
Method (5): an aromatic dihydroxy compound is
subjected to interfacial condensation polymerization
10 together with phosgene and an aromatic monohydroxy
compound (molecular weight controller) in excess
amounts relative to the amount of the aromatic di-
hydroxy compound, to prepare an aromatic carbonate
oligomer containing terminal groups comprised mainly
15 of aryl carbonate groups and having a number average
molecular weight of about 350 to 950 and, then, a
transesterification is performed between the
oligomer and an aromatic dihydroxy compound.
By any of Method (1), (2) and (3), an amorphous
20 aromatic polycarbonate prepolymer containing sub-
stantially no chlorine compound can easily be
produced advantageously. From such an amorphous
aromatic polycarbonate prepolymer, a porous, crys-
tallized, aromatic polycarbonate prepolymer and a
25 porous, crystallized aromatic polycarbonate, each
21 7 00 19
76
containing substantially no chlorine compound, can
advantageously be produced.
On the other hand, according to Method (4) or
(5) in which phosgene is used, each of the obtained
aromatic polycarbonate prepolymer which is a final
product of each of Methods (4) and (5) and the
aromatic polycarbonate oligomer which is an inter-
mediate product, contains a chlorine compound.
However, when each of the aromatic polycarbonate
prepolymer and the oligomer has a relatively low
molecular weight, the chlorine compound can easily
be removed from each of the prepolymer and the
oligomer. Therefore, even according to Method (4)
or (5), an aromatic polycarbonate having a lower
molecular weight and containing substantially no
chlorine compound can easily be obtained.
The aromatic dihydroxy compound and the diaryl
compound which may be used as raw materials for
preparing an amorphous aromatic polycarbonate pre-
polymer is represented by formulae (IX) and (X):
HO-Ar-OH (IX),
wherein Ar has the same meaning as defined
above; and
O
II
Ar30COAr3 (X),
-21 7 00 19
wherein Ar3 has the same meaning as defined
above.
Representative examples of diaryl carbonates
include substituted or unsubstituted diphenyl
carbonates represented by the formula:
(R7)P (R8)q
~Q -O C O-
U
wherein each of R~ and R8 independently represents a
hydrogen atom, a halogen atom, an alkyl group having
1 to 10 carbon atoms, an alkoxy group having 1 to 10
carbon atoms, a cycloalkyl group having from 5 to 10
ring carbon atoms or a phenyl group; and each of p
and q independently represents an integer of from 1
to 5; with the proviso that when p is an integer of
from 2 to 5, each R~ may be the same or different,
and when q is an integer of from 2 to 5, each R8 may
be the same or different.
Of these diphenyl carbonates, preferred are
diaryl carbonates having a symmetrical configura-
tion, such as Biphenyl carbonate, ditolyl carbonate
and Biphenyl carbonate substituted with a lower
alkyl group, e.g. di-t-butylphenyl carbonate. Of
these, Biphenyl carbonate is most preferred because
- 21 7 00 19
of the simplest structure.
The above-mentioned diaryl carbonates are used
individually or in combination. However, when two
or more different types of diaryl carbonates are
used, the reaction system becomes complicated with
little advantage. Therefore, it is preferred to use
one type of diaryl carbonate having a symmetrical
configuration, individually.
As the molecular weight controller to be
employed in the interfacial condensation polymeriza-
tion method, there may be mentioned the aromatic
monohydroxy compound represented by formula (XI):
Ar3-OH (XI)
wherein Ar3 has the same meaning as defined
above.
Preferable examples of aromatic monohydroxy
compounds include phenol, o-, m- or p-cresol, 2,6-
xylenol, p-t-butylphenol and p-octylphenols(inclu-
ding various position isomers). Of these, phenol.
and p-t-butylphenol are particularly preferred.
Further, another type of molecular weight
controller may also advantageously be used in combi-
nation with the above-mentioned aromatic monohydroxy
compound. Examples of molecular weight controllers
of this type include monohydric alcohols, such as
21 7 00 19
79
methanol and ethanol; haloformates, such as methyl
chloroformate, ethyl chloroformate, isopropyl
chloroformate and cyclohexyl chloroformate; monova-
lent thiols, such as methyl mercaptan and ethyl
mercaptan; monovalent halothioformates, such as
methyl chlorothioformate and ethyl chlorothiofor-
mate; monocarboxylic acid such as acetic acid,
propionic acid, benzoic acid, sodium acetate, acetic
anhydride and acetyl chloride, propionyl chloride
and derivatives thereof.
In order to facilitate the pre-polymerization,
a dibasic acid or a reactive derivative thereof may
optionally be used in an amount of 5 mole % or less
based on the number of moles of the aromatic dihy-
droxy compound. The above dibasic acid and reactive
derivatives thereof may be aliphatic, aromatic or
alicyclic. Examples of dibasic acids and reactive
derivatives thereof include dibasic acids, such as
terephthalic acid, isophthalic acid, phthalic acid,
naphthalene-1,5-dicarboxylic acid, diphenyl-2,2'-
dicarboxylic acid, cis-1,2-cyclohexane dicarboxylic
acid, oxalic acid, succinic acid, sebacic acid,
adipic acid, malefic acid and fumaric acid; and
alkali metal salts, alkaline earth metal salts,
amine salts and halides thereof.
8° 21 7 00 19
An explanation is given below with respect to
preferred modes of the method of the present inven-
tion for producing a porous, crystallized aromatic
polycarbonate. Examples of preferred modes include
the following methods (A), (B) and (C).
Method (A) for producing a porous, crystal-
lized, aromatic polycarbonate from an aromatic
dihydroxy compound and diaryl carbonate comprises
the steps of:
(1) reacting an aromatic dihydroxy compound
with an aromatic carbonate under heating at a tem-
perature sufficient and for a period of time suffi-
cient to prepare an amorphous prepolymer having a
number average molecular weight of from 1,000 to
15,000 and having terminal hydroxyl and aryl carbon-
ate groups (pre-polymerization);
(2) treating the amorphous prepolymer with
solvent under sufficient shearing force to crystal-
laze to a crystallinity of at least 5 % and simul-
taneously render porous the prepolymer, the shear-
ing force being sufficient to cause the resultant
powder form of porous, crystallized, aromatic poly-
carbonate prepolymer to have an average particle
diameter of 250 um or less, the resultant powder
form of porous, crystallized prepolymer having a
8, 21 7 00'(9
specific surface area of at least 0.2 m2/g; and
(3) heating the powder form of porous, crystal-
lized prepolymer, or heating an agglomerated powder
form or a granular form of porous, crystallized
prepolymer derived from the powder form of prepoly-
mer, at a temperature which is higher than the glass
transition temperature of the crystallized prepoly-
mer and at which the crystallized prepolymer is in
a solid state, to effect solid-state condensation
polymerization of the crystallized prepolymer,
thereby increasing the number average molecular
weight and the crystallinity of the crystallized
prepolymer to from 6,000 to 200,000 and at least
35 %, respectively, so that the resultant poly-
carbonate has a number average molecular weight and
a crystallinity which are, respectively, greater
than those of the crystallized prepolymer.
In method (A), an amorphous prepolymer is
prepared in the pre-polymerization step (1) and then
crystallized and rendered porous in step (2). Sub-
sequently, the porous, crystallized, prepolymer
obtained in Step (2) is subjected to solid-state
condensation polymerization in step (3). In pre-
polymerization step (1), a mixture of an aromatic
dihydroxy compound and a diaryl carbonate is heated,
82 2170019
while removing a by-produced aromatic monohydroxy
compound having a structure such that a hydroxyl
group is bonded to an aryl group derived from the
diaryl carbonate, to thereby obtain a prepolymer.
The number average molecular weight of the
amorphous prepolymer prepared in pre-polymerization
step (1) is generally within the range of from 1,000
to 15,000. The number average molecular weight of
the amorphous prepolymer can be controlled by appro-
priately selecting reaction conditions, such as
temperature, reaction time, pressure and agitation
rate. In general, the pre-polymerization is per-
formed at a temperature of from 100° to 320 °C,
preferably of from 160° to 280 °C, for a period of
from 0.5 to 20 hours under atmospheric pressure or
reduced pressure.
The pre-polymerization is preferably effected
in molten state without using a solvent. Alter-
natively, the pre-polymerization may be performed in
a solvent which is inert to the pre-polymerization
reaction, such as methylene chloride, chloroform,
1,2-dichloroethane, tetrachloroethane, dichloro-
benzene, tetrahydrofuran, diphenylmethane and di-
phenyl ether.
The molar ratio of the diaryl carbonate to the
2170019
83
aromatic dihydroxy compound is varied depending on
the types of the employed diaryl carbonate and
aromatic dihydroxy compound, the reaction condi-
tions, such as reaction temperature. The diaryl
carbonate may be used in an amount of from 0.6 to
1.8 moles, preferably from 0.7 to 1.6 moles, more
preferably from 0.8 to 1.5 moles, per mole of the
aromatic dihydroxy compound.
The amorphous prepolymer prepared in the above-
mentioned pre-polymerization generally comprises
terminal aryl carbonate groups represented, for
example, by the formula:
Ar3-OCO-
II
0
wherein Ar3 has the same meaning as defined
above,
and terminal hydroxyl groups derived from the
dihydroxydiaryl compound, which is represented, for
example, by the formula:
HO-Ar-
wherein Ar has the same meaning as defined above.
The crystallization and pore formation in step
(2) and the solid-state condensation polymerization
21 7 00 19
84
in step (3) are conducted in the same manner as
described hereinbefore in detail.
Method (B) for producing a crystallized
aromatic polycarbonate from an aromatic dihydroxy
compound and phosgene comprises the steps of:
(1) reacting an aromatic dihydroxy compound
with phosgene in the presence of a molecular weight
controller to prepare a prepolymer having a number
average molecular weight of from 1,000 to 15,000
(pre-polymerization);
(2) treating said prepolymer with solvent under
sufficient shearing force to crystallize to a crys-
tallinity of at least 5 $ and simultaneously render
porous said prepolymer, the shearing force being
sufficient to cause the resultant powder form of
porous, crystallized, aromatic polycarbonate pre-
polymer to have an average particle diameter of
250 um or less, the resultant powder form of porous,
crystallized prepolymer having a specific surface
area being at least 0.2 m2/g; and
(3) heating the powder form of porous, crystal-
lized prepolymer, or heating an agglomerated powder
form or a granular form of porous, crystallized
prepolymer derived from the powder form of prepoly-
mer, at a temperature which is higher than the glass
2~~~~ 19
transition temperature of the crystallized prepoly-
mer and at which the crystallized prepolymer is in
a solid state, to effect solid-state condensation
polymerization of the crystallized prepolymer,
5 thereby increasing the number average molecular
weight and the crystallinity of the crystallized
prepolymer to from 6,000 to 200,000 and at least
35 $, respectively, so that the resultant poly-
carbonate has a number average molecular weight and
10 a crystallinity which are, respectively, greater
than those of the crystallized prepolymer.
In method (B), the pre-polymerization in step
(1) may be conducted by a conventional method in
which an aromatic dihydroxy compound is reacted with
15 phosgene in the presence of the above-mentioned
molecular weight controller, an acid acceptor and a
solvent. Preferred examples of acid acceptors
include an aqueous alkali solution containing 5 to
10 $ by weight of an alkali, and a tertiary amine,
20 such as pyridine. Examples of solvents include
methylene chloride, chloroform, carbon tetra-
chloride, tetrachloroethylene, chlorobenzene and
xylene.
It is preferred that phosgene be added to the
25 reaction system by blowing the phosgene in gaseous
2~ ~ oo ~9
86
form into a mixture of an aromatic dihydroxy com-
pound, an acid acceptor, a molecular weight control-
ler and a solvent (particularly preferred is
methylene chloride), or by dissolving phosgene in a
solvent and dropping the solution into the mixture
of an aromatic dihydroxy compound and an acid accep-
tor. The molecular weight controller may be added
before, during or after the reaction of phosgene
with an aromatic dihydroxy compound, but it is pre-
ferred that the molecular weight controller be added
before or during the reaction. The reaction temper-
ature is generally in the range of from -30° to
100 °C and the reaction time is generally in the
range of from 1 minute to 10 hours.
The prepolymer prepared by the pre-polymeriza-
tion in step (1) has a number average molecular
weight of 1,000 to 15,000. This molecular weight
can be attained by appropriately selecting reaction
conditions, such as the amount of a molecular weight
controller, the amount of aqueous alkali solution,
the reaction temperature and the rate of the addi-
tion of phosgene. The prepolymer prepared by the
pre-polymerization generally comprises terminal
chloroformate groups (-ArOCOCl) and terminal alkali
metal-containing phenolate groups (such as -ArONa),
8, 2170019
in addition to aryl carbonate groups and hydroxyl
groups derived from the aromatic monohydroxy
compound used as a molecular weight controller. The
terminal chloroformate groups can be converted to
terminal hydroxyl groups by completely hydrolyzing
the terminal chloroformate groups into phenolate
groups by treatment with an aqueous alkaline
solution, and nutralizing the resultant alkali
metal-containing phenolate groups with an acid solu-
tion, followed by washing with pure water. In the
case where a monohydric alcohol, such as ethanol, or
a chloroformate of a monohydric alcohol, such as
ethyl chloroformate, is used as a molecular weight
controller in combination with an aromatic monohy-
droxy compound, the terminal groups of the prepoly-
mer are generally comprised of aryl carbonate
groups, alkyl carbonate groups, and hydroxyl groups.
Preferred is a porous, crystallized aromatic poly-
carbonate having its terminal groups comprised
substantially of hydroxyl groups and aryl carbonate
groups.
The prepolymer obtained by the pre-polymeriza-
tion in step (1) is generally in the form of a solu-
tion of the prepolymer in the organic solvent. The
method for obtaining a solid prepolymer from the
__z~ ~ ~o ~s
solution is not specifically restricted. For exam-
ple, the prepolymer solution is well washed and
neutralized, and then, (i) the solution is concen-
trated to dryness, followed by pulverization, or the
solution is concentrated to a wet mass, followed by
pulverization and drying, to obtain a solid; or (ii)
the solution is heated while vigorously stirring and
blowing steam to distill off the solvent.
The solid prepolymer obtained by the above
method may have already been partly crystallized.
However, the prepolymer has not yet be rendered
porous and, therefore, its specific surface area is
generally as small as 0.1 m2/g or less. In order to
prepare the porous, crystallized, aromatic poly-
carbonate prepolymer of the present invention from
the thus obtained solid prepolymer, the solid pre-
polymer as such or in a molten state is introduced
into a solvent and treated with the solvent under
sufficient shearing force to crystallize and render
porous the amorphous aromatic polycarbonate prepoly-
mer as described above. That is, the prepolymer is
treated under shearing force which is sufficient to
cause the resultant powdery, porous, crystallized,
aromatic polycarbonate prepolymer to have an average
particle diameter of 250 um or less.
21700 ~9
Examples of solvents to be used for treating
the prepolymer include acetone, methyl ethyl ketone,
methyl propyl ketone, xylene, ethyl acetate, aceto-
nitrile and toluene. Of these, acetone is
preferred.
The solid-state polymerization in step (3) is
conducted as described hereinbefore in detail. With
respect to the solid-state polymerization, it is
believed that when the terminal groups of the pre-
polymer are comprised not only of terminal phenyl
carbonate groups and terminal hydroxyl groups, but
also alkyl carbonate groups, such as ethyl carbonate
groups, not only advances the condensation polymeri-
zation reaction of the prepolymer while releasing
phenol and diphenyl carbonate, but also the poly-
condensation reaction advances while releasing
phenyl ethyl carbonate.
Method (C) for producing a crystallized
aromatic polycarbonate from an aromatic polycarbon-
ate oligomer and an aromatic dihydroxy compound
comprises the steps of:
(1) reacting an aromatic polycarbonate oligomer
having a number average molecular weight of from
about 350 to about 950 and having its terminal
groups comprised substantially of aryl carbonate
z~ ~ oo ~9
groups with an aromatic dihydroxy compound under
heating at a temperature sufficient and for a period
of time sufficient to prepare an amorphous prepoly-
mer having a number average molecular weight of from
5 1,000 to 15,000 and having terminal hydroxyl and
aryl carbonate groups;
(2) treating the amorphous prepolymer with
solvent under sufficient shearing force to crystal-
lize to a crystallinity of at least 5 $ and simul-
10 taneously render porous the prepolymer, the shear-
ing force being sufficient to cause the resultant
powder form of porous, crystallized, aromatic poly-
carbonate prepolymer to have an average particle
diameter of 250 um or less, the resultant powder
15 form of porous, crystallized prepolymer having a
specific surface area being at least 0.2 m2/g; and
(3) heating the powder form of porous, crystal-
lized prepolymer, or heating an agglomerated powder
form or a granular form of porous, crystallized
20 prepolymer derived from the powder form of prepoly-
mer, at a temperature which is higher than the glass
transition temperature of the crystallized prepoly-
mer and at which the crystallized prepolymer is in
a solid state, to effect solid-state condensation
25 polymerization of the crystallized prepolymer,
2170019
91
thereby increasing the number average molecular
weight and the crystallinity of the crystallized
prepolymer to from 6,000 to 200,000 and at least
35 ~, respectively, so that the resultant polycarbo-
nate has a number average molecular weight and a
crystallinity which are, respectively, greater than
those of the crystallized prepolymer.
In method (C), an aromatic polycarbonate
oligomer having its terminal groups comprised sub
stantially of aryl carbonate groups is used for the
pre-polymerization in step (1). As described above,
such an oligomer can easily be prepared by the
transesterification method or the interfacial poly-
condensation method.
An agglomerated powder form or a granular form
of porous, crystallized prepolymer, which may be
used in step (3) of each of Methods (A), (B) and
(C), can easily be obtained individually from the
powder form of porous, crystallized prepolymer in
the manner as described before in detail.
The crystallization in step (2) and the solid-
state polymerization in step (3) are conducted in
the same manner as described hereinbefore in detail.
In all the steps of each of the above methods,
i.e., the pre-polymerization, the crystallization of
92
2170019
the prepolymer and the solid-state polymerization,
the reaction may be carried out in a batch-wise
manner or in a continuous manner. Both the manners
may be employed in combination.
The powder form, the agglomerated powder form
or the granular form of porous, crystallized,
aromatic polycarbonate prepolymer of the present
invention can advantageously be used as a prepolymer
to be subjected to solid-state polymerization to
produce a polycarbonate. Further, the prepolymer
itself can also be used as a raw material for
producing a sintered product, a filter, an adsorbent
and a coating composition, or can be mixed with
other resins to prepare polymer alloys.
The powder form, the agglomerated form, or the
granular form of porous, crystallized, aromatic
polycarbonate of the present invention having a
desired molecular weight, which is formed by the
solid-state polymerization of the above-mentioned
prepolymer, may be directly introduced into an
extruder without cooling to pelletize it by melt-
extrusion, thereby obtaining colorless, transparent
pellets of a polycarbonate. Alternatively, the
powder agglomerated powder form or granular form of
porous, crystallized, aromatic polycarbonate may be
93 21 7 00 19
cooled before introducing it into an extruder.
Introduction of the polycarbonate into an extruder
without cooling is advantageous from the viewpoints
of energy saving in extrusion and increase of the
extrusion rate of the extruder. Further, the
granular form of polycarbonate has satisfactorily
high bulk density. Therefore, the granular form of
polycarbonate can be directly subjected to injection
molding or extrusion molding without being pelleti-
zed by melt-extrusion. Pelletization of a poly-
carbonate by melt-extrusion not only needs much
energy but also leads to a lowering of the quality
of the aromatic polycarbonate due to heat deteriora-
tion. In the case of the granular form of poly-
carbonate, pelletization can advantageously be
omitted.
According to the present invention, a wide
variety of aromatic polycarbonates, including not
only aromatic polycarbonate having a broad molecu-
lar weight distribution, but also aromatic poly-
carbonate having a narrow molecular weight distri-
bution, can be provided. When a prepolymer having a
narrow molecular weight distribution is used, an
aromatic polycarbonate having a narrow molecular
weight distribution can be obtained. On the other
94
21 7 00 19
hand, when a prepolymer having a broad molecular
weight distribution is used, an aromatic polycarbon-
ate having a broad molecular weight distribution can
be obtained. This is one of the remarkable features
of the present invention. As a criterion of the
molecular weight distribution, a ratio of a weight
average molecular weight (Mw) to a number average
molecular weight (Mn), i.e., Mw/Mn, is generally
used. With respect to a polymer prepared by a
condensation polymerization reaction, there has been
established a theory that, when the Mw/Mn is 2, the
polymer has the narrowest molecular weight distribu-
tion. From the viewpoint of the properties of the
polymer, such as flowability in molding, mechanical
strength and elongation, it is preferred that a
polymer have a narrow molecular weight distribution.
However, it is practically difficult to prepare a
polymer having an Mw/Mn of 2.5 or less, particularly
not 2.4 or less. In the conventional polymerization
methods, such as the transesterification method
which is known as a melt process, a polymerization
reaction system becomes very viscous before comple-
tion of the polymerization reaction, so that the
polymerization reaction does not advance uniformly.
According to this conventional method, it is
21 7 00't9
infeasible to obtain an aromatic polycarbonate
having a narrow molecular weight distribution. The
aromatic polycarbonate obtained by the conventional
transesterification method generally has an Mw/Mn of
5 more than 2.6. In the conventional phosgene process
which is frequently carried out on a commercial
scale, the obtained aromatic polycarbonate has an
Mw/Mn of from 2.4 to 3.5, generally from 2.5 to 3.2.
In contrast, an aromatic polycarbonate having an
10 Mw/Mn as low as from 2.2 to 2.5 can easily be
prepared by the method of the present invention.
The reason for this is believed to be that in the
stage of producing a prepolymer which has a rela-
tively low molecular weight, a prepolymer having a
15 narrow molecular weight distribution can easily be
obtained and such a prepolymer having a narrow
molecular weight distribution is used for producing
the polycarbonate.
The porous, crystallized, aromatic polycarbon-
20 ate of the present invention, for example, a porous,
crystallized, polycarbonate prepared using bisphenol
A, which is one of the most preferred polycarbonates
of the present invention, is white and opaque.
However, when this porous, crystallized, aromatic
25 polycarbonate is heated to a temperature higher than
21 7 00 19
96
its crystalline melting point or subjected to melt
molding, an amorphous aromatic polycarbonate having
good transparency can be obtained. This also is an
important feature of the aromatic polycarbonate of
the present invention. When an aromatic polycarbon-
ate is prepared from bisphenol A and diphenyl
carbonate by the conventional melt process, it is
necessary to react highly viscous raw materials with
each other under severe conditions, that is, at a
high temperature, i.e., about 300 °C, under highly
reduced pressure, i.e., 1 mmHg or less, for a pro-
longed period of time. Consequently, the obtained
polycarbonate inevitably assumes a light yellow
color due to the thermal decomposition of the poly-
mer or due to the oxidation of the polymer by the
action of a small amount of oxygen present in the
reaction system. In contrast, according to the
present invention, not only can the pre-polymeriza-
tion be performed at a relatively low temperature,
i.e., 250 °C or less, preferably 240 °C or less, in
a short period of time even when the transesterifi-
cation method is employed, but also both the treat-
ment for crystallization and pore formation and the
solid-state polymerization can be performed at a
relatively low temperature, i.e., 230 °C or less.
21 7 00 19
97
Consequently, in the method of the present inven-
tion, there is no danger of deterioration of the
polymer, differing from the case of the conventional
melt process, such as the conventional transesteri-
fication process.
The porous, crystallized, aromatic polycarbo-
nate of the present invention may optionally be
mixed with various additives such as heat stabili-
zers, antioxidants, mold release agents, fire retar-
dants and various inorganic fillers such as glass
fibers, and the resultant composition used in a wide
variety of fields, such as a engineering plastics
field. Moreover, the porous, crystallized, aromatic
polycarbonate of the present invention can advan-
tageously be kneaded with another polymer in order
to form a polymer alloy. Therefore, the porous,
crystallized, aromatic polycarbonate is particularly
useful as a raw material for the production of a
polymer alloy on a commercial scale.
An aromatic polycarbonate containing no
chlorine atom can be obtained in the present inven-
tion. The aromatic polycarbonate containing no
chlorine atom is extremely useful as a material for
an optical instrurnent and a material for electronic
equipment.
-. 2170019
98
Further, according to the present invention, it
is possible to produce not only an ultra-high
molecular weight polycarbonate having a number
average molecular weight of 15,000 or more by solid-
state polymerization, which is difficult or im-
possible to produce by the conventional phosgene
method or the conventional transesterification
method (melt method), but also a polycarbonate
having reactive hydroxyl groups at its terminals.
As aforedescribed, in the conventional phosgene
process for producing an aromatic polycarbonate on a
commercial scale, by-products including chlorine and
electrolytes, such as sodium chloride, are formed as
impurities. These impurities are disadvantageously
and inevitably contained in the final polycarbonate.
Further, a chlorine-containing compound, such as
methylene chloride, which is used as a solvent in a
large amount, is also likely to be contained as an
impurity in the polycarbonate. Such impurities ad-
versely affect the properties of the final poly-
carbonate. Conventionally, in order to decrease the
amount of impurities contained in the final poly-
carbonate, washing and other operations have been
conducted. However, thse operations are troublesome
and expensive, and it is infeasible to remove im-
21 7 00'9
99 _ . . _
purities completely from the resin.
By contrast, according to the present inven-
tion, even in the mode in which the use of phosgene
is involved, the product which is obtained directly
from phosgene is a prepolymer having a relatively
low molecular weight, and such a prepolymer can
easily be treated for removing impurities (such as
chlorine-containing compound) therefrom. Therefore,
the aromatic polycarbonate of the present invention
is completely free from such impurities and hence
excellent in quality. Moreover, naturally, any
troublesome process for removing impurities from the
final polycarbonate is not required. Accordingly,
the method of the present invention is commercially
advantageous.
Further, in the conventional transesterifica-
tion melt process, an expensive reactor is disadvan-
tageously required for attaining a reaction under
high viscosity, high temperature and high vacuum
conditions. Therefore, due to the high temperature,
the polymer is likely to be deteriorated. By
contrast, according to the method of the present
invention, such a special reactor is not required,
and the aromatic polycarbonate produced by the
method of the present invention has excellent
2170019
00
properties as described above.
The powder form, the agglomerated powder form
or the granular form of porous, crystallized,
aromatic polycarbonate prepolymer can be polymerized
at extremely high reaction rate by solid-state poly-
merization, without the danger of adhesion of the
prepolymer to the inner wall of the reactor and
adhesion between prepolymer particles. Thus, the
present invention is extremely useful for providing
an aromatic polycarbonate, which can easily, effi-
ciently be produced by solid-state polymerization on
a commercial scale.
21 7 00 19
101
Best Mode for Carrying Out the Invention
The present invention will be described in more
detail with reference to the following Examples,
which should not be construed as limiting the scope
of the present invention.
In the present invention, the molecular weight
is expressed in terms of a number average molecular
weight (hereinafter referred to simply as "Mn") and
a weight average molecular weight (hereinafter
referred to simply as "Mw") as measured by gel
permeation chromatography (GPC). For reference, the
molecular weight of TOUGHLOI~ A 2500 (registered
trademark of a polycarbonate manufactured and sold
by Idemitsu Sekiyukagaku K.K., Japan) is measured
and found to have an Mn of 10,700 and an Mw of
28,000.
The molar ratios with respect to terminal
groups in a prepolymer and a polycarbonate after
solid-state condensation polymerization are deter-
mined by high-performance liquid chromatography or
by nuclear magnetic resonance (NMR) spectroscopy.
The specific surface area is determined by
measuring the surface area of a sample by means of
ACCUSORB~-2100-02 (manufactured and sold by Shimadzu
Corp., Japan) using krypton gas, and dividing the
21 7 00 19
102
measured surface area by the Weight of the sample.
The average particle diameter of a prepolymer
in a solvent for crystallization is determined by
taking an aliquot from a uniformly mixed slurry of
the prepolymer, diluting the aliquot with the
solvent, applying a ultrasonic wave to the diluted
aliquot to disperse the prepolymer in the solvent,
casting the resultant dispersion on a glass plate,
drying the dispersion to deposit the prepolymer on
the glass plate and measuring the particle diameter
of the deposited prepolymer using a microscope.
The particle size distribution of dry particles
is determined by classifying particles into frac-
tions respectively remaining on 1,070 dun screen,
850 dun screen, 600 um screen, 250 um screen, 150 um
screen, 75 um screen and 50 um screen and a fraction
passing through 50 um screen by means of a micro-
type magnetic vibration screen classifier model M-2
(manufactured and sold by Tsutsui Rikagaku Kiki,
Japan), and measuring the weight of each of the
fractions.
The crystallinity is measured by the X ray
diffractometry as described hereinbefore.
In Examples 18 to 24, the compressive break
strength of a granular prepolymer and a granular
103
polycarbonate after solid-state condensatio 1p~1~ ~ 1
merization is determined as follows. That is,
using, for example, a Kiya type hardness meter, a
compressive force is applied between opposite sur-
faces of a sample, which each have an area of at
least about 1 mm2 and are apart from each other
substantially in parallel relationship at a distance
of about 1 mm. The load for application of a
compressive force is increased until the sample
breaks. The load (kgf/cm2) at which the sample
breaks is referred to simply as the load at break.
The measurement of the load at break is conducted 10
times. When a sample prepolymer or polycarbonate
does not have two surfaces which are apart from each
other substantially in parallel relationship, a
sample having such opposite surfaces is cut out from
the original sample, followed by measurement of
compressive break strength in the manner described
above. From the 10 values of load at break thus
obtained, the maximum and minimum values are
omitted, and the average of the remaining 8 values
is calculated. The compressive break strength is
represented by the calculated average value.
In Examples 33 and 34, the compressive break
strength (kgf/cm2) is measured using an Instron type
~ 4 ''~ 21 7 0 0 1 9
universal tester.
The partial pressure of phenol in a phenol-
saturated nitrogen gas used in solid-state condensa-
tion polymerization is determined from the vapor
pressure of phenol calculated according to the fol-
lowing formula shown on page 128 of Kagaku Binran II
(Handbook of Chemistry) (published in 1984 by
Maruzen Co., Japan).
1516.072
log P = 7.13457 -
174.569 + t
[wherein P represents a vapor pressure of phenol
(mmHg) and t represents a temperature (°C)].
In the following Examples, porous, crystal-
lized, aromatic polycarbonate prepolymer is often
referred to simply as "porous, crystallized pre-
polymer"; amorphous, aromatic, polycarbonate pre-
polymer is often referred to simply as "amorphous
prepolymer"; porous, crystallized, aromatic poly-
carbonate is often referred to simply as "porous,
crystallized polycarbonate"; shaped, porous, crys-
tallized, aromatic polycarbonate is often referred
to simply as "shaped, porous, crystallized poly-
carbonate"; and granular, porous, crystallized,
aromatic polycarbonate is often referred to simply
as "granular, porous, crystallized polycarbonate".
,05 297Q~ 19
Example 1
13.0 kg of 2,2-bis(4-hydroxyphenyl)propane
(hereinafter referred to as "bisphenol A") and
13.4 kg of diphenyl carbonate are charged into a
40 L glass-lined reactor provided with a stirrer, a
gas inlet and a gas outlet. The resultant mixture
is melted by heating to 180 °C and degassing is con-
ducted under reduced pressure, followed by heating
to 230 °C over a period of 3 hours. During the the
temperature elevation, nitrogen gas is flowed
through the reactor so that evaporated phenol is
discharged from the reactor. Simultaneously with
the termination of the temperature elevation, intro-
duction of nitrogen gas is terminated. Then, the
pressure in the reactor is stepwise reduced to
1 mmHg over a period of 2 hours. During the period
of the pressure reduction, by-produced phenol and
Biphenyl carbonate are continuously discharged from
the reactor. The reaction is further continued for
2 hours under reduced pressure of 1 mmHg to obtain
about 10 kg of an amorphous prepolymer having a
number average molecular weight of 4,000 and a molar
ratio of terminal hydroxyl groups to terminal phenyl
carbonate groups of 33/67 [hereinafter referred to
as "amorphous prepolymer (I)"]. About 10 kg of
2970019
106
molten amorphous prepolymer (I) is extruded in a
strand form at about 240 °C over a period of 1 hour
through a die having 40 orifices of 1 mm in diameter
into a blaring blender type acetone bath filled with
15 kg of acetone having a temperature of from 40 to
50 °C. Simultaneously with the extrusion, the
blender in the acetone bath is revolved at a rate as
high as 1,000 rpm so that the extruded strand is
drawn and stretched into a thin fiber. The thin
fiber is dipped in the acetone bath, and exposed to
strong shearing force by agitation, thereby being
crystallized, rendered porous and reduced to
particles. As a result, particles of a porous,
crystallized prepolymer are formed. The thus formed
particles in acetone have an average particle
diameter of 150 um. Then, acetone is distilled off
under reduced pressure while heating the acetone
bath to dry the porous, crystallized prepolymer.
The thus obtained porous, crystallized prepolymer is
white and opaque. When the surface of the porous,
crystallized prepolymer is observed by means of a
scanning electron micrograph, it is confirmed that a
large number of pores are present on the surface of
the crystallized prepolymer [see Fig. 1 (3060 x '
magnification)]. On the other hand, when a rela-
~~ ~ oo v~~
10~
tively large particle (about 800 um in diameter) of
the porous, crystallized prepolymer is broken with
forceps and the resultant section of particle of the
porous, crystallized prepolymer is observed by means
of a scanning electron micrograph, it is confirmed
that a large number of pores are also present on the
section [see Fig. 2 (1020 x magnification)]. For
the purpose of comparison, melted amorphous prepoly-
mer (I) is cooled to room temperature and the sur-
face of the cooled amorphous prepolymer (I) is
observed by means of a scanning electron micrograph.
As a result, it is confirmed that the surface of the
amorphous prepolymer (I) is smooth and has no pore
[see Fig. 3 (4400 x magnification)].
The above-obtained porous, crystallized prepoly-
mer has a specific surface area of 1.5 m2/g and a
crystallinity of 28 $.
10 kg of the porous, crystallized prepolymer is
charged into a cylindrical, gas flow type reactor
made of stainless steel (internal diameter: 60 cm,
height: 1 m) which is provided, at its bottom por-
tion, with a sintered filter having pores of from
about 40 to about 50 dun in diameter and having a
thickness of about 5 mm, and heated to 180 °C, fol-
lowed by solid-state condensation polymerization.
2~~ooi9
108
During the solid-state condensation polymerization,
heated nitrogen gas is uniformly introduced at a
rate of 10 m3(N.T.P.)/hr from the bottom portion of
the reactor through the sintered filter, and dis-
charged from the upper portion of the reactor. The
temperature of the polymerization is regulated by
controlling the temperature of the heated nitrogen
gas. The temperature is elevated from 180 °C to
220 °C at a temperature elevation rate of 10 °C/hr
and then kept at 220 °C for 5 hours, thereby obtain-
ing a porous, crystallized polycarbonate having an
Mn of 13,000 and an Mw of 31,200. The porous, crys-
tallized polycarbonate has a specific surface area
of 0.8 m2/g and a crystallinity of 45 %. A DSC
chart [obtained using a DSC analyzer (model DSC7
manufactured and sold by Perkin Elmer Co., U.S.A.);
the ordinate of the chart indicates heat flow (mW)
while the abscissa indicates temperature (°C)] of
the porous, crystallized polycarbonate is shown in
Fig. 9, in which the peak exhibiting the melting
point of the polycarbonate appears at 271 °C. From
the chart, it is found that the half-width is
4.3 °C. To the obtained porous, crystallized poly-
carbonate is added 250 ppm of tris(nonylphenyl)
phosphite as a heat stabilizer, and melt-extrusion
21 7 00't9
is conducted at 280 °C to obtain a colorless, trans-
parent, amorphous polycarbonate. When the amorphous
polycarbonate is injection-molded at 300 °C, no
silver streak occurs. With respect to the color of
the resultant shaped article, the L-value and b*-
value measured using a color and color-difference
meter Model CR-200b (Minolta Camera Co., Ltd.,
Japan) are 91.7 and 3.5, respectively, i.e., the
shaped article is colorless and transparent.
Example 2
10 kg of amorphous prepolymer (I) prepared in
substantially the same manner as in Example 1 is
melted and extruded at about 240 °C and then cooled
with water. After the cooling, pelletization is
conducted. The resultant amorphous pellets are
pulverized using a plastics pulverizer (manufactured
by Fritsch Co., West Germany) to obtain a powder
having a diameter of 1 mm or less.
An acetone bath as used in Example 1 is filled
with 15 kg of acetone and acetone is kept at 40 °C.
Into the acetone bath is gradually charged the above
obtained powder over a period of 1 hour while stir-
ring at the same rate as in Example 1, i.e.,
1,000 rpm to effect crystallization and pore forma-
tion. The resultant porous, crystallized prepoly-
110 21 7 00 19
mer in acetone has an average particle diameter of
180 um. Then, acetone is distilled off in substan-
tially the same manner as in Example 1 to dry the
porous, crystallized prepolymer. The scanning elec-
tron micrographs with magnifications of 1020, 3060
and 6020, respectively, of the surface of the thus
obtained porous, crystallized prepolymer are respec-
tively shown in Figs. 4 to 6. It is confirmed from
Figs. 4 to 6 that the porous, crystallized prepoly-
mer has pores having substantially uniform dia-
meters. The porous, crystallized prepolymer has a
specific surface area of 1.2 m2/g and a crystallini-
ty of 26
The above-obtained porous, crystallized pre-
polymer is subjected to solid-state condensation
polymerization in substantially the same manner as
in Example 1 to obtain a porous, crystallized poly-
carbonate having an Mn of 12,500 and an Mw of
29,600. When the porous, crystallized polycarbonate
is injection-molded in substantially the same manner
as in Example 1, the same colorless and transparent
shaped article having no silver streak as obtained
in Example 1 is obtained.
Example 3
10 kg of amorphous prepolymer pellets (about
21 7 00'9
",
2 mm in diameter, about 3 mm in length) prepared in
substantially the same manner as in Example 2, with-
out pulverization, are charged into an acetone bath
filled with 15 kg of acetone over a period of 1 hour
while stirring to effect crystallization. The
resultant porous, crystallized prepolymer in acetone
has an average particle diameter of 230 um. Then,
acetone is distilled off in substantially the same
manner as in Example 1 to dry the porous, crystal-
lized prepolymer. The thus obtained porous, crys-
tallized prepolymer has a particle diameter larger
than that of the porous, crystallized prepolymer
obtained in Example 2 (whilst some portion of the
porous, crystallized prepolymer maintains substanti-
ally the same size as that of the starting pellet).
The porous, crystallized prepolymer is less white
and assumes slight transparency, as compared to the
porous, crystallized prepolymer obtained in Example
2. The porous, crystallized prepolymer has a speci-
fic surface area of 0.4 m2/g and a crystallinity of
23 %.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 2 except
that the period of time for which the temperature is
21 7 00 19
112
kept at 220 °C is changed to 14 hours, thereby
obtaining a porous, crystallized polycarbonate
having an Mn of 13,000 and an Mw of 31,400. In this
Example, a longer polymerization time is required
than in Examples 1 and 2.
Comparative Example 1
kg of amorphous prepolymer powder prepared
in substantially the same manner as in Example 2 is
dissolved in 100 .t of methylene chloride and then,
10 methylene chloride is distilled off at room tempera-
ture under reduced pressure. Then, the resultant
powder is placed in a vacuum drier, and dried at
40 °C overnight to obtain a powder having a crystal-
linity of 25 $ and a specific surface area of
0.07 m2/g. The crystallized prepolymer powder is
subjected to solid-state condensation polymerization
in substantially the same manner as in Example 1
except that polymers being formed are sampled 8
hours, 13 hours and 24 hours after the initiation of
the polymerization at 220 °C. From the measurement
of the molecular weight of each of the samples, it
is found that the number average molecular weight of
the polycarbonate reaches 8,100, 8,900 and 9,200 at
respective polymerization times of 8, 13 and 24
hours. No significant further increase is observed
2171019
113
in the number average molecular weight of the poly-
carbonate, and the desired number average molecular
weight, i.e., Mn=12,500 cannot be attained. Poly-
carbonate having an Mn of 12,500 corresponds to a
commercially available aromatic polycarbonate resin
of the grade classified as high viscosity grade.
The process which cannot provide a polycarbonate
having an Mn of 12,500, is commercially disadvan-
tageous.
Comparative Example 2
10 kg of amorphous prepolymer powder prepared
in substantially the same manner as in Example 2 is
placed in an atmosphere of tetrahydrofuran vapor-
saturated nitrogen gas at about 40 °C for 24 hours
to effect crystallization. The resultant crystal-
lazed prepolymer has a specific surface area of
0.05 m2/g and a crystallinity of 20 $.
The crystallized prepolymer is subjected to
solid-state condensation polymerization in substan-
tially the same manner as in Example 1 except that
the period of time for which the temperature is kept
at 220 °C is changed to 24 hours. As in Comparative
Example 1, the number average molecular weight of
the polycarbonate cannot be increased to a desired
level. The obtained polycarbonate has an Mn of
21 ~ ~Q 19
114
8,800.
Comparative Example 3
kg of 2,2-bis [(4-methyl carbonate)phenyl~
propane is charged into the same reactor as used in
5 Example 1, and stirred while introducing dry argon
gas heated to 280 °C at a flow rate of 30 ~t(N.T.P.)
/hr to effect reaction at 280 °C for 7 hours, there-
by obtaining an amorphous prepolymer having an Mn of
1,700 and an Mw of 3,300. The prepolymer is treated
10 with methylene chloride to effect crystallization,
and then dried in substantially the same manner as
in Comparative Example 1. Thereafter, the resultant
crystallized prepolymer is subjected to solid-state
condensation polymerization in substantially the
same manner as in Example 1 except that polymers
being formed are sampled 24 hours and 50 hours after
the initiation of the polymerization at 220 °C.
From the measurement of the molecular weight of each
of the samples, it is found that the number average
molecular weight reaches 6,500 (Mw=16,800) and 7,100
(Mw=18,000) at respective polymerization times of 24
and 50 hours. The molecular weight of the poly-
carbonate cannot be increased to a desired level.
Comparative Example 4
Polymerization for obtaining an amorphous pre-
21 7 00 19
115
polymer (pre-polymerization) is conducted in sub-
stantially the same manner as in Comparative Example
3, except that 3 g of dibutyltin oxide is used as a
catalyst and that the polymerization temperature and
polymerization time are changed to 250 °C and 6
hours, to obtain ~n amorphous prepolymer having an
Mn of 3,100 and an Mw of 6,400. The amorphous pre-
polymer is crystallized with methylene chloride, and
then dried in substantially the same manner as in
Comparative Example 1. Then, the resultant crystal-
lined prepolymer is subjected to solid-state conden-
sation polymerization in substantially the same
manner as in Example 1 except that polymers
being formed are sampled 24 hours and 40 hours after
the initiation of the polymerization at 220 °C.
From the measurement of the molecular weight of each
of the samples, it is found that the number average
molecular weight of the polycarbonate reaches 8,500
and 10,300 at respective polymerization times of 24
and 40 hours. When the polycarbonates having Mn's
of 8 500 and 10,300 are individually injection-
molded at 300 °C to prepare shaped articles, silver
streaks markedly occur on each of the shaped arti-
cles, and the surface of each of the shaped articles
has hazy, opaque portions.
~- - 21 7 00 19
116
Example 4
kg of an amorphous polycarbonate prepolymer
having a number average molecular weight of 3,900
and a molar ratio of terminal hydroxyl groups to
5 terminal phenyl carbonate groups of 35/65, which is
prepared in substantially the same manner as in
Example 1 except that, in the polymerization step,
the temperature is elevated to 250 °C and kept at
235 °C is melted by heating at about 240 °C and
10 extruded in a thin strand form, over a period of
1 hour, into a blaring blender acetone bath filled
with 12 kg of acetone having a temperature of 40°to
50 °C through a die having 40 orifices of 1 mm in
diameter. Simultaneously with the extrusion, the
acetone and the prepolymer are agitated with a stir-
rer provided with blades at a rate as high as
500 rpm to effect crystallization and pore formation
while effecting reduction of the prepolymer to fine
powder. The resultant acetone slurry of a porous,
crystallized prepolymer is opaque, and it is found
that a great number of fine particles are present in
the acetone slurry. The thus formed particles in
acetone have an average particle diameter of 180 ~.un.
When the acetone slurry is allowed to stand, a
porous, crystallized prepolymer precipitates so that
117 ~ 2 't 7 0 0 19
the upper portion of the acetone solution becomes
transparent. When a portion of the transparent
upper portion is taken out and the acetone contained
therein is distilled off, a polycarbonate oligomer
having a number average molecular weight of 710 is
obtained. From the amount of the portion taken out
and the amount of the oligomer obtained, it is found
that the oligomer is present in the acetone solution
in an amount of 390 g per 12 kg of acetone.
The acetone slurry of the porous, crystallized
prepolymer is heated while stirring to distill off
the acetone, so that the porous, crystallized pre-
polymer is dried. The particle diameter distribu-
tion of the thus obtained porous, crystallized pre-
polymer is measured. A fraction of the porous,
crystallized prepolymer which passes through 50 um
screen is 2.8 % by weight, based on the weight of
the porous, crystallized prepolymer, and fractions
of the porous, crystallized prepolymer which remain
on 50 um screen, 75 um screen, 150 um screen, 250 um
screen, 600 um screen, 850 um screen and 1070 ~m
screen are respectively 3.4 % by weight, 12.6 % by
weight, 11.7 % by weight, 20.7 % by weight, 26.8 %
by weight, 15.4 % by weight and 6.5 % by weight,
based on the weight of the porous, crystallized
2~7 pp 19
118
prepolymer. Since the polycarbonate oligomer serves
as an adhesive during the drying, agglomeration of
the powder of the porous, crystallized prepolymer
occurs to form secondary particles, leading to a
large particle diameter. The porous, crystallized
prepolymer has a specific surface area of 1.7 m2/g
and a crystallinity of 29 $.
9 5 kg of the porous, crystallized prepolymer
(which has preliminarily been heated to 140 °C) is
subjected to solid-state condensation polymerization
using a 70 l tumbler type, solid-state condensation
polymerization reactor made of a stainless steel.
The solid-state condensation polymerization is
conducted under conditions such that nitrogen gas is
introduced little by little into the reactor while
keeping the pressure at 1 to 2 mmHg using a vacuum
pump and that the temperature is elevated from
140 °C to 180 °C over 30 minutes and further
elevated from 180 °C to 220 °C at a rate of
10 °C/hr, and then kept at 220 °C for 7 hours,
thereby obtaining a porous, crystallized polycarbon-
ate having an Mn of 11,500. There is observed no
adhesion of the polycarbonate to the inner wall of
tumbler, and observed almost no adhesion of the
polycarbonate to a bag filter disposed between the
21 7 00 19
119
tumbler and the vacuum pump. The porous, crystal-
lized polycarbonate obtained by the solid-state
condensation polymerization is melted, extruded and
pelletized at 280 °C to obtain colorless, trans-
parent pellets of an amorphous aromatic polycarbon-
ate. The thus obtained pellets is injection-molded
at 300 °C to obtain a plate. The plate exhibits a
transmittance (according to ASTM D1003) of 90.4 %
and a haze (according to ASTM D1003) of 0.3 %.
Example 5
An acetone slurry of a porous, crystallized
prepolymer obtained in substantially the same manner
as in Example 4 is separated into the porous, crys-
tallized prepolymer and an acetone solution by means
of a batch type centrifugal separator. 9 kg of the
thus obtained porous, crystallized prepolymer and a
separately prepared 650 g of an acetone solution of
a polycarbonate oligomer having an Mn of 850 (oli-
gomer concentration: 30 % by weight) are mixed well,
and acetone is distilled off while heating and stir-
ring, to obtain a dried, porous, crystallized pre
polymer. The particle diameter distribution of the
thus obtained porous, crystallized prepolymer is
determined by classifying the particles into frac-
tions by means of screens The major fraction is
21 7 00 19
120
one containing the particles of the prepolymer hav-
ing passed through the 600 um screen. The amount of
the prepolymer contained in the fraction having
passed through the 50 um screen is only 3 5 $ by
weight, based on the total weight of the prepolymer
The porous, crystallized prepolymer has a specific
surface area of 1.5 m2/g and a crystallinity of
28 $.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 4 to
obtain a porous, crystallized polycarbonate having
Mn of 10,800, a specific surface area of 0.8 m2/g
and a molar ratio of terminal hydroxyl groups to
terminal phenyl carbonate groups of 4/96.
Neither adhesion of the polycarbonate to the
inner wall of tumbler nor clogging of the bag filter
with the polycarbonate is observed.
Example 6
An amorphous prepolymer having a number average
molecular weight of 5,100 and a molar ratio of
terminal hydroxyl groups to terminal phenyl carbon-
ate groups of 30/70 is prepared in substantially the
same manner as in Example 1 except that the period
of time for keeping the pressure at 1 mmHg is
21 7 00 19
121
changed to 3 hours. The amorphous prepolymer is
subjected to solid-state condensation polymerization
in substantially the same manner as in Example 4 to
obtain a porous, crystallized prepolymer having a
specific surface area of 1.3 m2/g. The particle
diameter distribution of the thus obtained porous,
crystallized prepolymer, which is determined by
classifying of the particles into fractions by means
of screens, is such that the major fraction is one
containing the particles of the prepolymer having
passed through the 850 um screen. The amount of the
particles contained in the fraction having passed
through the 50 um screen is 1.3 % by weight, based
on the total weight of the prepolymer.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 4 except
that the period of time for keeping the prepolymer
at 220 °C is changed to 6 hours, thereby obtaining a
porous, crystallized polycarbonate having Mn of
10,200, a crystallinity of 41 %, a crystalline melt-
ing point of 262 °C and a specific surface area of
0.6 m2/g. Neither adhesion of the polycarbonate to
the inner wall of tumbler nor clogging of the bag
filter with the polycarbonate is observed.
21 7 00 ~9
122
Example 7
An aqueous solution prepared by dissolving
64.8 g of sodium hydroxide in 800 g of water, is
mixed with 137 g of bisphenol A, 400 ml of methylene
chloride and 1.7 g of phenol to prepare an emulsion.
Into the emulsion is gradually blown 58.5 g of phos-
gene over a period of 1 hour while stirring and
while maintaining the temperature at from 10° to
20 °C, to advance a reaction. To the resultant
reaction mixture is added 0.12 g of triethylamine,
followed by stirring for 1 hour, thereby separate
the mixture into a methylene chloride layer (a pre-
polymer solution in methylene chloride) and an aque-
ous layer. The methylene chloride layer is collect-
ed, and to the methylene chloride layer is added an
aqueous sodium hydroxide solution to convert the
remaining chloroformate groups into phenolate
groups, followed by neutralization with phosphoric
acid and by sufficient washing with water. From the
resultant solution of the prepolymer in methylene
chloride, the methylene chloride is distilled off,
followed by drying overnight using a vacuum dryer.
The resultant dried prepolymer is pulverized in
substantially the same manner as in Example 2 and
then charged in a small size blaring blender contain-
__ 2170019
123
ing 300 g of acetone while stirring at 1,000 rpm,
thereby effecting crystallization and pore formation
of the prepolymer. Then, acetone is distilled off
to dryness to obtain a dried, porous, crystallized
prepolyrner. The thus obtained porous, crystallized
prepolymer has an Mn of 2,300, an Mw of 4,600, a
crystallinity of 28 %, a specific surface area of
1.3 m2/g and a molar ratio of terminal hydroxyl
groups to terminal phenyl carbonate groups of 45/55.
The analysis of chlorine by potentiometric titration
and atomic absorption shows that any chlorine-
containing compound is not contained in this
polymer.
Then, the porous, crystallized prepolymer
(which has preliminarily been heated to 140 °C) is
subjected to solid-state condensation polymerization
using a rotary evaporator under conditions such that
the pressure is in the range of from 2 to 3 mmHg and
that the temperature is elevated from 140 °C to
180 °C over 10 minutes and further elevated from
180 °C to 220 °C at a temperature elevation rate of
10 °C/hr, and then kept at 220 °C for 4 hours,
thereby obtaining a porous, crystallized polycarbon-
ate having number average molecular weight of 9,500
and a specific surface area of 0.5 m2/g.
.. 2~ 7 00 t9
124
Example 8
An aqueous solution prepared by dissolving 62 g
of sodium hydroxide in 800 g of water, is mixed with
137 g of bisphenol A, 400 ml of methylene chloride
and 1.7 g of phenol to prepare an emulsion. Into
the emulsion is gradually blown 55 g of phosgene
over a period of 1 hour while stirring and maintain-
ing the temperature at from l0~to 20 °C. Into the
resultant reaction mixture is blown 6 g of phosgene
over a period of 5 minutes. To the mixture, 0.13 g
of triethylamine is added, followed by stirring for
1.5 hours. Then, the mixture is subjected to sepa-
ration of the methylene chloride layer from the
aqueous layer and, then, to purification, and sub-
sequently subjected to crystallization and pore
formation in substantially the same manner as in
Example 7, thereby obtaining a porous, crystallized
prepolymer. The thus obtained porous, crystallized
prepolymer has an Mn of 3,300, an Mw of 6,500, a
crystallinity of 28 %, a specific surface area of
1.0 m2/g and a molar ratio of terminal hydroxyl
groups to terminal phenyl carbonate groups of 40/60.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 7,
21 7 00 19
125
thereby obtaining a porous, crystallized polycarbon-
ate having a weight average molecular weight of
25,000 (Mw/Mn=2.3) and a specific surface area of
0.5 m2/g.
Example 9
Pre-polymerization is conducted in substantial-
ly the same manner as in Example 1 except that 13 kg
of bisphenol A and 13 kg of diphenyl carbonate are
used, thereby obtaining 12 kg of an amorphous pre-
polymer having an Mn of 3,200 and a molar ratio of
terminal hydroxyl groups to terminal phenyl carbon-
ate groups of 50/50. From the bottom portion of the
pre-polymerization reactor, 10 kg of the molten
amorphous prepolymer at about 240 °C is extruded
into an acetone bath filled with 15 kg of acetone
from the upper portion of the acetone bath through a
die having 40 orifices of 1 mm in diameter over a
period of 1 hour. The bottom portion of the acetone
bath is connected with a suction port of a centri-
fugal pump provided with cutter blades (tradename:
Santoku Cutter Pump, Model SD-K, manufactured and
sold by Sanwa Tokushu Seiko Co., Japan) through a
pipe, and a delivery port of the pump is connected
with a side portion of the acetone bath through a
pipe. By operating the centrifugal pump provided
2170018
126
with cutter blades, the contents of the acetone bath
are circulated through the acetone bath and the
pump. When passed through the pump, the prepolymer
is reduced to fine powder by the action of the cut-
ter blades rotating at a high rate. An acetone
slurry containing a porous, crystallized prepolymer
is obtained by extruding the prepolymer into acetone
while operating the pump. The porous, crystallized
prepolymer in the acetone slurry has an average
particle diameter of 190 um. Acetone is distilled
off from the acetone slurry in substantially the
same manner as in Example 1 to dry the porous, crys-
tallized prepolymer. The thus obtained porous,
crystallized prepolymer has a specific surface area
of 1.9 m2/g and a crystallinity of 31 %. Scanning
electron micrographs of the porous prepolymer with
magnifications of 3,060 and 6,020 are respectively
shown in Figs. 7 and 8.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 1 except
that the temperature is elevated to 230 °C and kept
at 230 °C for 10 hours, thereby obtaining a porous
polycarbonate having an ultra-high molecular weight,
i.e., an Mn of 26,000 and an Mw of 65,000. After
2170019
127
keeping the temperature at 230 °C for 10 hours, the
temperature is further elevated to 240 °C and kept
at 240° for 10 hours, thereby obtaining a porous,
crystallized polycarbonate having an ultra-high
molecular weight, i.e., an Mn of 40,000 and Mw of
100,000.
Example 10
Pre-polymerization, crystallization and solid-
state condensation polymerization are conducted in
substantially the same manner as in Example 1 except
that 6.5 kg of bisphenol A and 13.3 kg of 2,2-
bis[(4-phenyl carbonate)phenyl]propane
CH3
( OO --- OCO-~O -~ -~O~-p~0 -O ) are used
CH3 O
in place of 13.0 kg of bisphenol A and 13.4 kg of
Biphenyl carbonate. By the pre-polymerization and
the crystallization, a porous, crystallized
prepolymer having an Mn of 2,500, a specific surface
area of 0.8 m2/g, a crystallinity of 31 % and a
molar ratio of terminal hydroxyl groups to terminal
phenyl carbonate groups of 42/58 is obtained. By
the solid-state condensation polymerization, a
porous, crystallized polycarbonate having an Mn of
13,000 is obtained.
217001
128
Example 11
Pre-polymerization and crystallization are
conducted in substantially the same manner as in
Example 1 except that the amount of Biphenyl carbon-
ate is changed to 12.1 kg to obtain a porous, crys-
tallized prepolymer having Mn of 4,300, a specific
surface area of 1.5 m2/g, a crystallinity of 30 %
and a molar ratio of terminal hydroxyl groups to
terminal phenyl carbonate groups of 65/35. The
porous, crystallized prepolymer is subjected to
solid-state condensation polymerization in substan-
tially the same manner as in Example 1 to obtain a
porous, crystallized polycarbonate having an Mn of
12,300 and a molar ratio of terminal hydroxyl groups
to terminal phenyl carbonate groups of 98/2. That
is, the terminals of the obtained porous, crystal-
lazed polycarbonate are substantially hydroxyl
groups. Incidentally, when the porous, crystallized
polycarbonate is reacted , while heating, with glycidyl
polyether, which is prepared from bisphenol A and
epichlorohydrin, in the presence of triethylene-
tetramine as a curing agent, a cured product which
is insoluble in tetrahydrofuran is obtained.
Example 12
An aqueous solution prepared by dissolving
r 21 7 pp'9
129
64.8 g of sodium hydroxide in 800 g of water, is
mixed with 137 g of bisphenol A, 400 ml of methylene
chloride and 1.7 g of phenol to prepare an emulsion.
Into the emulsion is gradually blown 58.5 g of phos-
gene over a period of 1 hour while stirring and
maintaining the temperature at l0~to 20 °C to ad-
vance a reaction. To the resultant reaction mixture
is added a solution prepared by dissolving 0.8 g of
ethyl chloroformate in 40 ml of methylene chloride.
To the mixture, 6 g of phosgene is blown over a
period of 5 minutes and 0.15 g of triethylamine is
added, followed by stirring for 2 hours. Then, the
resultant mixture is subjected to separation of a
methylene chloride layer from an aqueous layer and,
then, to purification, and subsequently subjected to
crystallization and pore formation in substantially
the same manner as in Example 7. Thus, a porous,
crystallized prepolymer is obtained. The obtained
porous, crystallized prepolymer has an Mn of 3,000,
an Mw of 6,300, a specific surface area of 1.3 m2/g,
a crystallinity of 25 % and a molar ratio of the
total of terminal hydroxyl groups and terminal ethyl
carbonate groups (molar ratio of terminal hydroxyl
groups to terminal ethyl carbonate groups is 26/23)
to terminal phenyl carbonate groups of 49/51.
130 ' 2 'l 7 0 0 '~ 9
The porous, crystallized prepolymer is charged
in a rotary evaporator provided with a heating oven
at 180 °C, then heated from 180 °C to 220 °C at a
temperature elevation rate of 5 °C/hr, and kept at
220 °C for 4 hours while rotating the evaporator
under reduced pressure of from 2 to 3 mmHg while
introducing dry nitrogen little by little to advance
a reaction, thereby obtaining a porous, crystallized
polycarbonate having a weight average molecular
weight of 24,000 (Mw/Mn=2.2) and a specific surface
area of 0.6 m2/g.
Example 13
An aqueous solution prepared by dissolving 58 g
of sodium hydroxide in 800 g of water, is mixed with
124 g bisphenol A, 400 ml of methylene chloride and
1.2 g of phenol to prepare an emulsion. Into the
emulsion is gradually blown 53 g of phosgene over a
period of 1 hour while stirring and maintaining the
temperature at 10°to 20 °C to advance a reaction.
Into the resultant reaction solution is further
blown 6 g of phosgene over a period of 5 minutes.
To the mixture, 0.15 g of triethylamine is added,
followed by stirring for 2 hours. Then, the resul-
taut mixture is subjected to separation of an
ethylene chloride layer from an aqueous layer and,
21 7 00 19
then, to purification, and subsequently subjected to
crystallization and pore formation in substantially
the same manner as in Example 7. Thus, a porous,
crystallized prepolymer is obtained. The porous,
crystallized prepolymer has an Mn of 9,100, a crys-
tallinity of 21 %, a specific surface area of
0.8 m2/g and a molar ratio of terminal hydroxyl
groups to terminal phenyl carbonate groups of 90/60.
The porous, crystallized prepolymer is subject-
ed to solid-state condensation polymerization in
substantially the same manner as in Example 7 except
that the period of time for keeping the prepolymer
at 220 °C is changed to 5 hours, to thereby obtain a
porous, crystallized polycarbonate having an Mn of
11,200 and a specific surface area of 0.3 m2/g.
Example 14
148 g of bisphenol, 1.4 g of p-tert-butyl
phenol, 0.8 g of phenol, 0.50 g of methanol, 162 g
of dry pyridine and 600 ml of methylene chloride are
charged in a flask and 65 g of phosgene is blown
into the flask over a period of 90 minutes while
stirring and maintaining the temperature at 10° to
20 °C. Then, 400 ml of methylene chloride is addi-
tionally charged in the flask and 50 ml of methylene
chloride containing 5 g of phosgene is dropwise
2170019
132
added while stirring and a reaction is advanced for
90 minutes. Then, the resultant reaction mixture is
added to 900 ml of 10 $ by weight hydrochloric acid,
followed by sufficiently stirring. Thereafter, the
resultant mixture is subjected to separation of a
methylene chloride layer from an aqueous layer and,
then, to purification, and subsequently subjected to
crystallization and pore formation in substantially
the same manner as in Example 7. Thus, a porous,
crystallized prepolymer is obtained. The porous,
crystallized prepolymer has an Mn of 3,600, a crys-
tallinity of 23 ~, a specific surface area of
1.8 m2/g and a molar ratio of the total of terminal
hydroxyl groups and terminal methyl carbonate groups
(molar ratio of terminal hydroxyl groups to terminal
methyl carbonate groups is 16/36) to terminal aryl
carbonate groups (terminal p-tert-butylphenyl
carbonate groups and terminal phenyl carbonate
groups) of 52/48.
Then, the porous, crystallized prepolymer is
subjected to solid-state condensation polymerization
in substantially the same manner as in Example 12
except that the period of time for keeping the pre-
polymer at 220 °C is changed to 10 hours, thereby
obtaining a porous, crystallized polycarbonate hav-
21 7 00 99
133
ing a weight average molecular weight of 24,000
(Mw/Mn=2.5).
Example 15
An aqueous solution prepared by dissolving 60 g
of sodium hydroxide in 850 g of distilled water is
mixed with 146 g of bisphenol A, 400 ml of methylene
chloride and 1.7 g of phenol to prepare an emulsion.
Into the emulsion is gradually blown 62 g of phos-
gene at a temperature of from 10°to 20 °C over a
period of 1 hour while stirring to effect reaction.
Then, a solution prepared by dissolving 1.3 g of
terephthaloyl chloride in 160 ml of methylene
chloride is added to the reaction mixture. There-
after, 6.4 g of phosgene is blown into the reaction
mixture and, 10 minutes after completion of the
blowing, 0.16 g of triethylamine is added thereto.
The reaction mixture is stirred for 1 hour.
From the reaction mixtures, a layer of
methylene chloride containing a prepolymer is
separated. The layer is washed with 0.1N hydro-
chloric acid and then with water.
Added to the thus obtained methylene chloride
solution of the prepolymer is 10 ppm of a disodium
salt of bisphenol A. The methylene chloride solu-
tion of the prepolymer is subjected to distilla-
134 2'~ 7 ~ ~ ~ 9
tion-off of the methylene chloride therefrom and
then subjected to crystallization in substantially
the same manner as in Example 7, to obtain a
porous, crystallized prepolymer. The thus porous,
crystallized prepolymer has a number average mole-
cular weight of 3,200, a weight average molecular
weight of 6,500, a crystallinity of 25 %, and a
specific surface area of 1.0 m2/g. The porous, crys-
tallized prepolymer is subjected to solid-state
condensation polymerization in substantially the
same manner as in Example 12, to obtain a porous,
crystallized polycarbonate having a weight average
molecular weight of 33,000 (Mw/Mn=2.4).
Example 16
An aqueous solution prepared by dissolving
64.8 g of sodium hydroxide in 800 g of distilled
water is mixed with 137 g of bisphenol A, 400 ml of
methylene chloride and 1.7 g of phenol to prepare an
emulsion. Into the emulsion is gradually blown
58.5 g of phosgene at a temperature of from 10° to
20 °C over a period of 2 hours while stirring to
advance reaction.
Then, 6 g of phosgene is blown into the reac-
tion mixture over a period of 5 minutes. 0.15 g of
triethylamine is added to the reaction mixture, and
217 00't9
135
stirred for two hours. The reaction mixture is
subjected to purification and then subjected to
crystallization in substantially the same manner as
in Example 7, to obtain a porous, crystallized
prepolymer. The porous, crystallized prepolymer has
a number average molecular weight of 3,300, a weight
average molecular weight of 6,500, a crystallinity
of 28 % and a specific surface area of 1.0 m2/g, and
a molar ratio of terminal hydroxyl groups to termi-
nal phenylcarbonate groups of 40:60. 100 g of
porous, crystallized prepolymer is charged into a
glass-made gas flow type reactor of 50 mm in inner
diameter having a glass filter (pore size: about 40-
50 um) attached to one end thereof. Nitrogen aac
fed into the reactor through the glass filter at a
gas flow rate of 120 liters (N.T.P.)/hour, and
solid-state condensation polymerization is performed
at 210 °C under atmospheric pressure for a period of
three hours. Thus, there is obtained a porous,
crystallized polycarbonate having a weight average
molecular weight of 25,000 (Mw/Mn=2.3) and a speci-
fic surface area of 0.5 m2/g.
Example 17
An aqueous solution prepared by dissolving
64.8 g of sodium hydroxide in 800 g of water is
13s ' 21 7 00 19
mixed with 137 g of bisphenol A, 400 ml of methylene
chloride and 18 g of phenol to prepare an emulsion.
Into the emulsion is gradually blown 58.5 g of phos-
gene at a temperature of from l0~to 20 °C over a
period of 1 hour while stirring to effect reaction.
Further, 6 g of phosgene is blown into the reaction
mixture over a period of 5 minutes, and 0.15 g of
triethylamine is added thereto. The reaction mix-
ture is stirred for two hours. A layer of methylene
chloride is separated. The separated layer is neu-
tralized with phosphoric acid, and then sufficiently
washed with water. After distilling off the methyl-
ene chloride, the remainder is vacuum-dried to ob-
tain an oligomer having a molar ratio of terminal
hydroxyl groups to terminal phenyl carbonate groups
of 2:98. The oligomer has a number average molecu-
lar weight of 800. 28.4 g of bisphenol A is mixed
with 100 g of the oligomer. The resultant mixture
is subjected to melt polymerization at 230 °C, and
then subjected to crystallization in substantially
the same manner as in Example 2, to obtain a porous,
crystallized prepolymer having a number average
molecular weight of 3,800,a specific surface area of
0.9 m2/g and a molar ratio of terminal hydroxyl
groups to terminal phenyl carbonate groups of 58:42.
,37 ~. . 21 7 00 19
The analysis of this prepolymer shows that any chlo-
rine-containing compound is not contained in the
prepolymer. The obtained porous, crystallized pre-
polymer is subjected to solid-state condensation
polymerization in substantially the same manner as
in Example 12, to thereby obtain a porous, crystal-
lized polycarbonate having a weight average molecu-
lar weight of 28,300 (Mw/Mn=2.4).
Example 18
An acetone slurry of porous, crystallized pre-
polymer obtained in substantially the same manner as
in Example 1 is dried to have an acetone content of
35 % by weight. The resultant moist powder is
subjected to granulation at about 40 °C by using a
small size extruder (Pelleter BXKF-1 manufactured
and sold by Fuji Poudal Co., Japan), to prepare a
granular, crystallized prepolymer having a diameter
of about 2 mm and an average length of about 3 mm.
The thus prepared granular crystallized prepolymer
is dried at 120 °C for 2 hours. The thus obtained
granular prepolymer has a number average molecular
weight of 4,000, a molar ratio of terminal hydroxyl
groups to terminal phenylcarbonate groups of 33/67,
a specific surface area of 2.2 m2/g, a compressive
break strength of 7 kgf/cm2, and a crystallinity of
138
22 %.
21 7 00 ~9
100 g of the granular crystallized prepolymer
is placed in a glass-made gas flow type reactor of
50 mm in inner diameter having a glass filter (pore
size: about 40-50 um) attached to one end thereof.
Nitrogen gas is introduced into the reactor through
the glass filter at a gas flow rate of 150
l(N.T.P.)/hr, and solid-state condensation polymeri-
zation is performed under atmospheric pressure at
210 °C for 3 hours. As a result, there is obtained
a granular, crystallized polycarbonate having a
number average molecular weight of 12,100 and a
crystallinity of 45 %. The shape of the granular
polycarbonate after the polymerization is nearly the
same as that of the prepolymer before the polymeri-
zation. This means that the pulverization of the
granules does not occur during the polymerization.
The granular, porous crystallized polycarbonate
has a compressive break strength of 43 kgf/cm2 and
an equilibrium moisture content of 0.04 %. This
equilibrium moisture content is as low as about one-
tenth of that of a commercially available amorphous
polycarbonate pellet.
Example 19
An amorphous prepolymer having a number average
.._ a 21 7 00 19
139
molecular weight of 3,800 and a molar ratio of
terminal hydroxyl groups to terminal phenyl carbon-
ate groups of 50/50, and containing no chlorine-
containing compound therein, which is prepared in
substantially the same manner as in Example 1 except
that the amount of diphenyl carbonate is changed to
13 kg, is subjected to crystallization and granula-
tion in substantially the same manner as in Example
18, to obtain a granular, porous, crystallized pre-
polymer of a cylindrical shape having a diameter of
about 1 mm and a length of about 3 mm. The thus
obtained granular, porous, crystallized prepolymer
has a number average molecular weight of 3,800, a
molar ratio of terminal hydroxyl groups to terminal
phenyl carbonate groups of 50/50, a specific surface
of 1.9 m2/g, a compressive break strength of
11 kgf/cm2, and a crystallinity of 25 $.
100 g of the granular, porous, crystallized
prepolymer is subjected to solid-state condensation
polymerization in substantially the same manner as
in Example 18, except that the polymerization is
conducted at 210 °C for 3 hours and then at 220 °C
for 3 hours, thereby obtaining a granular, porous,
crystallized polycarbonate.
The thus obtained granular, porous, crystal-
__ r 2~~0019
140
lazed polycarbonate has a number average molecular
weight of 17,100 and a crystallinity of 51 %. The
shape of the granular, porous, crystallized poly-
carbonate after the polymerization is nearly the
same as that of the prepolymer before the polymeri-
zation. This means that the pulverization of the
granules does not occur. The granular, crystallized
polycarbonate has a compressive break~strength of
55 kgf/cm2 and an equilibrium moisture content of
0.04 %.
Comparative Example 5
The crystallized prepolymer as prepared in
Comparative Example 1 is subjected to granulation in
substantially the same manner as in Example 18, to
obtain a granular, crystallized prepolymer of a
cylindrical shape having a diameter of about 2 mm
and a length of about 3 mm. The obtained granular,
crystallized prepolymer has a specific surface area
of 0.04 m2/g.
The granular, crystallized prepolymer is
subjected to solid-state condensation polymerization
in substantially the same manner as in Example 18,
to obtain a polycarbonate having a number average
molecular weight of 8,100. During the polymeriza-
tion, any pulverization of the granules does not
21 7 00 19
141
occur.
Example 20
Substantially the same moist powder as used in
Example 18 is granulated using a compression molding
machine under pressure of 1 tf/cm2 to obtain a
granular, porous, crystallized prepolymer of a
cylindrical shape having a diameter of about 10 mm
and a length of about 5 mm. The obtained granular,
porous, crystallized prepolymer is dried at 120 °C
for 2 hours. Then, the granular, porous, crystal-
lazed prepolymer has a number average molecular
weight of 3,900, a molar ratio of terminal hydroxyl
groups to terminal phenylcarbonate groups of 35/65,
a specific surface area of 2.1 m2/g, a compressive
break strength of 26 kgf/cm2, and a crystallinity of
22 $.
100 g of the granular, porous, crystallized
prepolymer is subjected to solid-state condensation
polymerization in substantially the same manner as
in Example 18 except that the polymerization is
conducted at 220 °C for 2 hours, to obtain a granu-
lar, porous, crystallized polycarbonate having a
number average molecular weight of 12,900 and a
crystallinity of 40 $. The shape of the granular,
porous, crystallized polycarbonate after the poly-
142
2170019
merization is nearly the same as that of the pre-
polymer before the polymerization. This means that
the pulverization of the granules does not occur.
The granular, porous, crystallized polycarbonate has
a compressive break strength of 120 kgf/cm2.
Examples 21 to 24
Amorphous prepolymers are individually prepared
from bisphenol A, diphenyl carbonate and each of
dihydroxyaryl compounds indicated in Table 1. Each
of the amorphous prepolymers is subjected to crys-
tallization and pore formation, granulation, and
solid-state condensation polymerization, in substan-
tially the same manner as in Example 18, to thereby
obtain a granular, porous, crystallized, aromatic
polycarbonate. The properties of the porous cr s
Y -
tallized prepolymers and the polycarbonates are
shown in Table 1. The crystallinity of each of the
porous, crystallized prepolymers is in the range of
from 20 to 38 $. Any pulverization of the granules
does not occur during the solid-state condensation
polymerization. The crystallinity of each of the
granular, porous, crystallized polycarbonates ob-
tained by the solid-state condensation polymeriza-
tion is in the range of from 40 to 58
2170019
143
N ~
N
H M ~ ~ V1
Q
a ro
m '-' °o 0 00 0
>. i '~~ '~. °
U
v
N
N O '~ '1 ri
>
11 a O .f1 O O
p J x ~ .-i o~ r-1
N O O O
~O f ~' 4.
,7 M M Q' 1~1
ro
0
~-a ~ o ~ .1 ~ ,n
v,
.-1 N H .-1 - \
A. ~ ,
'8 N
.; $~.~~-~.~
a
~a s ~ a
a
x
x o r~, x r~,
x r, x o x
O a ° x u~ a
a
O
O O
N
fn ~ !N
5~c' I U - O U
o O G
n, O r,,
x x
A x x a x a a o v
x
N N N
2 ~, ~0 19
144
Example 25
Pre-polymerization and crystallization using
acetone are conducted in substantially the same
manner as in Example 1 except that 13.0 kg of bis-
phenol A and 13.2 kg of diphenyl carbonate are
employed, to obtain a porous, crystallized prepoly-
mer having a number average molecular weight of
4,100, a molar ratio of terminal hydroxyl groups to
terminal phenyl carbonate groups of 37/63, a crys-
tallinity of 25 $, and a specific surface area of
1.1 m2/g. The thus obtained porous, crystallized
prepolymer is charged into a glass-made gas flow
type reactor having an inner diameter of 15 mm and
provided at its bottom with a glass filter having
pores of about 40 to 50 um in diameter. Then,
solid-state condensation polymerization is conducted
at 210 °C for 2 hours under atmospheric pressure
while introducing nitrogen gas into the reactor
through the glass filter at a flow rate of
2.5 t(N.T.P.)/hr relative to 2 g of the porous,
crystallized prepolymer, thereby obtaining a porous,
crystallized polycarbonate having a number average
molecular weight of 10,800.
Examples 26 to 28 and Comparative Examples 6 and 7
In each of these Examples and Comparative
2170019
145
Examples, solid-state polymerization is conducted in
substantially the same manner as in Example 25,
except that the flow rate of nitrogen gas, the reac-
tion time and the reaction temperature are individu-
ally changed to those indicated in Table 2, to
obtain porous, crystallized polycarbonates. The
results are shown in Table 2.
' 217 00 19'
146
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v o 0 0 0 0
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U
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z~
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0 0 0 0 0
N ri ri r1 r-/
N N N N N (~ .,.1
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N
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.rl
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N la
M (~'1 M 00 ("1 1~ ~ ~r
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vD f~ 00 .~ ,~ b
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N N N ri 10 r~ ~ jJ ((f
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21 7 OA 19
147
Example 29
Pre-polymerization is conducted in substantial-
ly the same manner as in Example 1 except that
13.0 kg of bisphenol A and 13.3 kg of diphenyl
carbonate are employed. The thus obtained amorphous
prepolymer is subjected to crystallization and pore
formation using acetone, followed by drying, in
substantially the same manner as in Example 1,
thereby obtaining a porous, crystallized prepolymer
having a number average molecular weight of 4,100, a
molar ratio of terminal hydroxyl groups to terminal
phenylcarbonate groups of 35/65, a crystallinity of
25 $, and a specific surface area of 1.0 m2/g.
The porous, crystallized prepolymer (which has
preliminarily been heated to 180 °C) is subjected to
solid-state condensation polymerization by using a
glass-made gas flow type reactor having an inner
diameter of 15 mm under conditions such that the
pressure is maintained at atmospheric pressure while
introducing, as an inert gas, nitrogen gas which is
saturated with phenol at 0 °C (a partial pressure of
phenol: 0.028 mmHg), at a flow rate.of 1.25 l
(N.T.P.)/hr, per g of the porous, crystallized pre-
polymer, and the temperature is elevated from 180 °C
to 210 °C over a period of 30 minutes and then kept
r 21 7 00 19
148
at 210 °C for 2.5 hours, thereby obtaining a porous,
crystallized polycarbonate having a number average
molecular weight of 11,400.
Example 30 and Comparative Example 8
Substantially the same porous, crystallized
prepolymer as used in Example 29 is subjected to
solid-state condensation polymerization in substan-
tially the same manner as in Example 29 except that
nitrogen gases saturated with phenol respectively at
50 °C (Example 30) and at 63 °C (Comparative Example
8) are individually employed as an inert gas, to
obtain porous, crystallized polycarbonates. The
partial pressure of phenol in the phenol-saturated
nitrogen gas and the number average molecular weight
of the resultant polycarbonate are shown in Table 3.
Table 3
Partial pressure of Number average
phenol in phenol- molecular weight
saturated nitrogen of polycarbonate
(mmHg)
~xample 301 2.3 I 6,800
ompara-
ive 5.7 4,300
xample 8
149
As is apparent from Table 3, when the partial
pressure of phenol in the phenol-saturated nitrogen
gas is 2.3 mmHg, the number average molecular weight
is promptly increased to 6,800, whereas when the
partial pressure of phenol is 5.7 mmHg, the number
average molecular weight is only slowly increased to
4,300 from 4,100 of the prepolymer.
Example 31
Solid-state condensation polymerization is
conducted in substantially the same manner as in
Example 29 except that a granular, porous crystal-
lized prepolymer having a diameter of about 1 mm and
a length of from about 0.5 to about 2.0 cm, a number
average molecular weight of 3,980, a molar ratio of
terminal hydroxyl groups to terminal phenyl carbon-
ate groups of 36/64, a crystallinity of 25 $ and a
specific surface area of 0.9 m2/g is employed,
thereby obtaining a porous, crystallized polycarbon-
ate having a number average molecular weight of
10,500.
Example 32
The same granular, porous, crystallized poly-
carbonate as used in Example 31 is subjected to
solid-state condensation polymerization using a
moving bed, gas flow type reactor made of SUS 304
,50 '2~~ooi~
steel having an inner diameter of 15 cm and an
effective length of 1 m and provided with an air
pump and a gas-cooling device. The granular, porous
crystallized polycarbonate is introduced into the
reactor from its upper portion at a rate of
1.2 kg/hr at a temperature of 210 °C for 20 hours
while introducing nitrogen gas from the bottom
portion of the reactor at a flow rate of 6 m3
(N.T.P.)/hour. Nitrogen gas containing phenol is
discharged from the reactor, cooled to 0 °C for
liquefying and removing excess phenol, and then
heated to 210 °C. The heated gas is then reintro-
duced in the reactor. From 7 to 20 hours after the
initiation of the operation, a granular, porous
crystallized polycarbonate having a number average
molecular weight in the range of from 10,800 to
11,000 is recovered from the bottom portion of the
reactor at a rate of 1.2 kg/hour. In this method,
nitrogen gas is advantageously recycled.
The partial pressure of phenol of the recycled
gas at a temperature of 0 °C is 0.028 mmHg, which is
calculated by the formula described hereinbefore.
Example 33
The same porous, crystallized aromatic poly-
carbonate as obtained in Example 1 is subjected to
~~ 7 0 0 19
press molding at 30 °C under pressure of 1,000 kgf/
cm2, to thereby obtain a pressed sheet (15 cm x
15 cm x 3 mm). The sheet has an apparent density of
1.03 g/cm3 and a specific surface area of 0.3 m2/g.
Accordingly, the sheet, even after the press mold-
ing, is porous.
In a DSC chart of the thus obtained shaped
article of porous, crystallized polycarbonate
(pressed sheet), a peak representing the crystalline
melting point of the polycarbonate is observed at
271 °C. The shaped article of porous, crystallized
polycarbonate has a crystallinity of 45 % and a
compressive break strength of 25 kgf/cm2 as measured
using an Instron type universal tester.
Example 34
A porous, crystallized polycarbonate having Mn
of 13,000 as obtained in Example 1 is subjected to
press molding at 200 °C under pressure of 500
kgf/cm2, to obtain a pressed sheet (15 cm x 15 cm x
3 mm). The thus obtained shaped article of porous,
crystallized polycarbonate (a pressed sheet) has an
apparent density of 1.05 g/cm3 and a specific sur-
face area of 0.08 m2/g. The crystallized poly-
carbonate exhibits a peak of a crystalline melting
point at 273 °C in a DSC chart thereof and has a
152
crystallinity of 46 % and a compressive-break
strength of 150 kgf/cm2 as measured using an Instron
type universal tester.
Brief Description of the Drawings
Fig. 1 is a scanning electron micrograph of the
surface of the particle of porous, crystallized
prepolymer of the present invention obtained in
Example 1 (3060 x magnification).
Fig. 2 is a scanning electron micrograph of the
cross-section of the particle of porous, crystal-
lized prepolymer of the present invention obtained
in Example 1, which has been broken with forceps
(1020 x magnification).
Fig. 3 is a scanning electron micrograph of the
amorphous prepolymer (I) obtained by pre-polymeriza-
tion in Example 1 (4400 x magnification).
Fig. 4 is a scanning electron micrograph of the
surface of the particle of porous, crystallized
prepolymer obtained in Example 2 (1020 x magnifica-
tion).
Fig. 5 is a scanning electron micrograph of a
portion of the particle shown in Fig. 4, which is
taken with higher magnification (3060 x magnifica-
tion).
1s3 21 7 00 1 9
Fig. 6 is a scanning electron micrograph of a
portion of the particle shown in Fig. S, which is
taken with higher magnification (6020 x magnifica-
tion).
Fig. 7 is a scanning electron micrograph of the
particle of porous, crystallized prepolymer of the
present invention obtained in Example 9 (3060 x
magnification).
Fig. 8 is a scanning electron micrograph of a
portion of the particle shown in Fig. 7, which is
taken with higher magnification (6020 x magnifica-
tion).
Fig. 9 is a DSC chart of the porous, crystal-
lized, polycarbonate of the present invention
obtained in Example 1.
Fig. 10 and Fig. 11 show examples of X-ray
diffraction patterns of a prepolymer before being
subjected to crystallization and after being
subjected to crystallization, respectively.
Industrial Applicability
The porous, crystallized, aromatic polycarbon-
ate prepolymer of the present invention can readily
be converted by solid-state condensation polymeriza-
tion to a porous, crystallized, aromatic polycarbon-
ate. The porous, crystallized, aromatic polycarbon-
217 00 19
154
ate of the present invention can readily be molded
to obtain a shaped, porous, crystallized polycarbon-
ate. The porous, crystallized, aromatic polycarbon-
ate and the shaped, porous, crystallized polycarbon-
ate of the present invention have excellent heat
resistance and solvent resistance and exhibit advan-
tageously low water absorption so that these are
suited for use as a filter material, an adsorbent or
the like. The porous, crystallized, aromatic poly-
carbonate and the shaped, porous, crystallized poly-
carbonate of the present invention can also readily
be molded by a melt process into an article useful
as engineering plastics, such as an optical element
and an electronic component.
The conventional phosgene process has drawbacks
in that chlorine-containing compounds attributed to
phosgene as a raw material and methylene chloride as
a solvent inevitably remain in the final polycarbon-
ate product despite complicated, costly steps for
removing them, and in that it is difficult to obtain
a polycarbonate having an ultra-high molecular
weight. On the other hand, the conventional
transesterification process also has drawbacks in
that a highly expensive reactor usable under
extremely high temperature and vacuum conditions is
217 00 19
155
necessary, and that it is difficult to perform poly-
merization without thermal degradation and to obtain
a polycarbonate having an ultra-high molecular
weight.
By contrast, the prepolymer and the polycarbon-
ate of the present invention are free from the
above-mentioned drawbacks of the prior art proces-
ses. Moreover, in the present invention, a reactive
hydroxyl group can readily be introduced in an
aromatic polycarbonate.
Accordingly, the porous, crystallized, aromatic
polycarbonate prepolymers and porous, crystallized
aromatic polycarbonates of the present invention as
well as the production methods of the present inven-
15~ tion, can advantageously be utilized, especially in
the field of engineering plastics which have been
rising in importance.
