Note: Descriptions are shown in the official language in which they were submitted.
2168630
METHOD FOR PRODUCING AN AROMATIC POLYCARBONATE
BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates to a method for
producing an aromatic polycarbonate. More particuIar-
ly, the present invention is concerned with a novelmethod for producing an aromatic polycarbonate, which
comprises feeding, to a feeding zone having a forami-
. nous plate, a molten monomer mixture of an aromatic
dihydroxy compound and a diaryl carbonate and/or a
molten prepolymer obtained by a process comprisingreacting an aromatic dihydroxy compound with a diaryl
carbonate, wherein the foraminous plate has at least
one hole, and the feeding zone communicates, through
the hole, with a polymerization zone comprising a
wire-wetting fall polymerization reaction zone having
at least one wire in correspondence with the hole, the
wire being securely held at one end thereof in an upper
end portion of the wire-wetting fall polymerization
reaction zone and extending downwardly through the
,r.
2168630
-
wire-wetting fall polymerization reaction zone; and
allowing the monomer mixture and/or the prepolymer to
pass downwardly through the foraminous plate and fall
along and in contact with the wire through a wire-
wetting fall polymerization reaction zone, thereby
effecting a polymerization of the monomer mixture
and/or the prepolymer during the wire-wetting fall.
2. Discussion of Related Art
In recent years, aromatic polycarbonates have been
widely used in various fields as engineering plastics
having excellent heat resistance, impact resistance and
transparency. With respect to methods for producing
aromatic polycarbonates, various studies have hereto-
fore been made. Of the methods studied, a process
utilizing an interfacial polycondensation between an
aromatic dihydroxy compound, such as 2,2-bis(4-hydroxy-
phenyl)propane (hereinafter, frequently referred to as
"bisphenol A"), and phosgene has been commercially
practiced.
However, the interfacial polycondensation process
has problems in that it is necessary to use phosgene,
which is poisonous, that a reaction apparatus is likely
to be corroded with chlorine-containing compounds, such
as hydrogen chloride and sodium chloride, which are
by-produced, and methylene chloride which is used as a
2168630
solvent in a large quantity, and that difficulties are
encountered in separating and removing impurities, such
as sodium chloride, and residual methylene chloride,
which adversely affect properties of a produced poly-
mer.
With respect to a method for producing an aromatic
polycarbonate from an aromatic dihydroxy compound and a
diaryl carbonate, in a conventionally known melt poly-
condensation process, a polycarbonate is produced by
performing an ester exchange reaction between bisphenol
A and diphenyl carbonate in the molten state, whileremoving a by-produced phenolic compound (phenol).
Unlike the interfacial polycondensation process, the
melt polycondensation process has an advantage in that
a solvent need not be used. However, the melt polycon-
densation process has a serious problem, namely; sincethe viscosity of polymer being formed increases during
the progress of the polymerization reaction, it becomes
difficult to remove by-produced phenol from the poly-
merization reaction system efficiently, thus making it
difficult to achieve a high degree of polymerization
with respect to polycarbonate produced.
Various polymerizers have been known for use in
producing aromatic polycarbonates. An agitation type
polymerizer vessel equipped with an agitator is widely
2168630
used. The agitation type polymerizer vessel equipped
with an agitator is advantageous in that it exhibits
high volumetric efficiency and has a simple construc-
tion, so that polymerization on a small scale can be
efficiently carried out. However, the agitation type
polymerization vessel has a problem in that, as men-
tioned above, the by-produced phenol becomes difficult
to remove from the polymerization reaction system
efficiently in the production of aromatic polycarbon-
ates on a commercial scale, so that it is difficult to
achieve a high polymerization rate.
Specifically, a large-scale agitation type poly-
merizer vessel generally has a greater ratio of liquid
volume to vaporization area than a small-scale one. In
other words, the depth of a reaction mixture in the
polymerizer is large. In such a case, even if the
degree of vacuum of the polymerization reaction zone is
raised in order to achieve a high degree of polymeriza-
tion in the lower part of the agitation vessel, the
polymerization proceeds under virtually high pressuredue to the weight of the reaction mixture, so that
phenol and the like cannot be efficiently removed.
To solve the above-mentioned problem, various
attempts have been made to remove phenol and the like
from high viscosity polymer being formed. For example,
2168630
Examined Japanese Patent Application Publication No.
50-19600 (corresponding to GB-1007302) discloses the
use of a screw type polymerizer having a vent. Exam-
ined Japanese Patent Application Publication No. 53-
5718 (corresponding to U.S. Patent No. 3,888,826)
describes a thin film evaporation type reactor, such as
a screw evaporator and a centrifugal film evaporator.
Further, Unexamined Japanese Patent Application Laid-
Open Specification No. 2-153923 discloses a method in
which a combination of a thin film evaporation type
apparatus and a horizontal stirring polymerizer vessel
is used. These polymerizers, including an agitation
type polymerizer vessel, have a common drawback in that
they have a rotary driving part in the main body, which
rotary driving part cannot be completely sealed, so
that when the polymerization is conducted under high
vacuum, a small amount of oxygen inevitably leaks into
the reaction system, leading to discoloration of the
final polymer. When a sealant is used to prevent the
leak-in of oxygen into the reaction system, the sealant
unavoidably gets mixed into the final polymer, so that
the quality of the final polymer is lowered. These
polymerizers also have a serious maintenance problem in
that, even if the seal effect is high at the beginning
of the operation of the polymerizer, the seal effect is
2168630
inevitably lowered during the continuous operation for
a prolonged period of time.
A fall polymerization process, in which polymeriz-
ing material is allowed to pass downwardly through a
perforated plate and fall, so that polymerization of
the polymerizing material is effected during the fall
(in this process there is no need of using a polymeriz-
er having a rotary driving part in a main body
thereof), is known as a method for producing resins
other than aromatic polycarbonates. For example, U.S.
Patent No. 3,110,547 discloses a method for producing a
polyester having a desired molecular weight, in which a
polyester having a low degree of polymerization is
. allowed to fall in the form of filaments through a
vacuum zone. In the technique of this U.S. Patent,
since recirculation of the fallen polymer and repeti-
tion of the fall causes a lowering of the quality of
the final polyester, the polymerization is finished
upon one-time fall without recirculation. However,
with respect to such a method, many drawbacks have been
pointed out. For example, concerning a method of
spinning a polyester having a low degree of polymeriza-
tion through a spinneret into a vacuum zone to effect
polycondensation thereof, ~m; ned Japanese Patent
Application Publication No. 48-8355 contains a descrip-
2168630
tion such that when polymerizing material (-not having a
satisfactorily high spinnability) is fed into a reac-
tor, filaments being polymerized are likely to be
broken, so that the quality of the polycondensate is
drastically lowered. Low molecular weight polyconden-
sate scattering from the filaments sticks to the sur-
face of the spinneret to smudge the spinneret and,
hence, it becomes difficult for the filaments to fall
straight down through the spinneret, so that the fila-
ments are caused to contact one another to bring about
breakage of the filaments or are caused to join one
another, thus hindering the polymerization reaction.
Further, observation windows easily get clouded and,
hence, observation becomes difficult, so that an ob-
server has difficulty in ascertaining an appropriate
time for the replacement of smudged spinnerets with
fresh ones. In the above Japanese patent document, it
is further described that, for the above reasons, when
producing a polyester and a polyamide, it is preferred
to employ a fall process in which a polymer having a
low degree of polymerization is allowed to flow down
along and in contact with a porous material arranged
vertically in a reaction vessel. However, the above
Japanese patent document contains no description about
aromatic polycarbonates.
2168630
Aside from a polymerization method, wi-th respect
to a method for removing a residual monomer from poly-
merization products, U.S. Patent No. 2,719,776 proposes
a process of spinning a lactam polymerization product,
which comprises allowing the product to pass through a
perforated plate and fall in the form of filaments,
whereby the residual monomer is removed by evaporation.
However, many disadvantages accompanying this method
have been pointed out. For example, Une~m;ned Japa-
nese Patent Application Laid-Open Specification No.
53-17569 points out that the method of U.S. Patent No.
2,719,776 has various disadvantages. That is, in the
method of the above-mentioned U.S. Patent, when the
evaporation of the volatiles is small, filaments can be
formed, whereas when the evaporation of the volatiles
is large, filaments unfavorably suffer foaming, making
it difficult to carry out the monomer-removing opera-
tion smoothly. Further, this method can be applied
only to a polymerization product having a viscosity in
a relatively narrow range suitable for forming fila-
ments. Moreover, in this method, when an inert gas isintroduced into the column in which this method is
practiced, filaments are caused to contact and join one
another due to the turbulence of the flow of inert gas.
To solve such disadvantages, Unexamined Japanese Patent
2168630
Application Laid-Open Specification No. 53-17569 pro-
poses a fall process which comprises providing a linear
support arranged vertically, and allowing a high vis-
cosity material to pass through a perforated plate or
spinneret and fall along and in contact with the linear
support. This Japanese patent document proposes this
fall process as a method for producing polyesters, such
as polyethylene terephthalate and polybutylene tereph-
thalate, and polyamides, such as nylon 6 and nylon 66.
However, in this Japanese patent document, there is no
mention of aromatic polycarbonates. Further, the
Japanese patent document does not contain any descrip-
tion about measures for solving the problem of the
- smudge of the spinneret which also often occurs when a
polyester or a polyamide is allowed to pass through the
spinneret and fall along and in contact with the linear
support.
~m; ned Japanese Patent Application Publication
No. 4-58806 describes a process for producing a polyes-
ter by the polycondensation of bis-(~-hydroxy alkyl)
terephthate, in which an early stage polycondensate is
allowed to fall along and in contact with a linear
support hung vertically from a spinneret in an inert
gas atmosphere, thereby performing further polymeriza-
tion of the polycondensate. This Japanese patent
2168630
document does not mention any measure for solving theproblem of the smudge of the spinneret which takes
place during the operation of such a process. Further,
this patent document is also silent about aromatic
polycarbonates. This silence about aromatic polycar-
bonate can be understood from the fact that even if an
attempt is made to produce a polycarbonate by replicat-
ing working examples of this patent document under same
conditions as described therein, not only does a poly-
mer obtained suffer discoloration, but also the spin-
neret is likely to be smudged. Then, not only does itbecome impossible to perform a continuous operation for
a long time, but also a polycarbonate of high quality
cannot be produced. This fact clearly shows that the
method or process preferably used for the production of
a polyester is not always applicable to the production
of a polycarbonate.
As is apparent from the above, a polymerization
method comprising allowing a polymerizing material to
pass through a perforated plate or a spinneret and fall
in the form of filaments or comprising allowing a
polymerizing material to pass through a perforated
plate or a spinneret and fall along and in contact with
a linear support, has been known for the production of
a polyester and a polyamide, but not known for the
2168630
production of an aromatic polycarbonate at-all.
SUMMARY OF THE INVENTION
The present inventors have extensive and intensive
studies with a view toward solving the above-mentioned
problems of the prior art.
As a result, it has unexpectedly been found that
by adopting a wire-wetting fall polymerization method
in which a polymerizing material is allowed to pass
downwardly through a foraminous plate and fall along
and in contact with a wire through a wire-wetting fall
polymerization zone, the object of the present inven-
tion can be attained.
It is, therefore, a primary object of the present
invention to provide a melt polycondensation process
for producing a colorless and high quality aromatic
polycarbonate at a high polymerization rate and stably
for a prolonged period of time, using an apparatus
which is excellently sealed under high vacuum condi-
tions, and is easy to maintain.
The foregoing and other objects, features and
advantages of the present invention will become appar-
ent from the following detailed description and append-
ed claims taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
tl68630
Figs. 1 and 2 respectively show two forms of
wire-wetting fall polymerization apparatus usable in
the present invention;
Figs. 3 to 9 are diagrams showing various systems
for practicing the method of the present invention; and
Figs. 10 to 12 show various manners for securely
holding at least one wire at one end thereof in an
upper end portion of a wire-setting fall polymerization
reaction zone.
Description of Reference Numerals
(Figs. 1 and 2)
101 : Inlet for a polymerizing material
102 : Recirculation line
103 : Foraminous plate
104 : Wire
105 : Gas feed port
106 : Vent
107 : Recirculation pump
108 : Discharge pump
109 : Outlet
110 : Main body of wire-wetting fall polymerizer
111 : Molten polymer
(Fig. 3)
201 - 211 : Numerals assigned in connection with free-
fall polymerizer
2168630
101A - lllA : Numerals assigned in connecti-on with
first wire-wetting fall polymerizer
101B - lllB : Numerals assigned in connection with
second wire-wetting fall polymerizer
201 : Inlet for a starting material
101A, 101B : Inlet for a polymerizing material
202, 102A, 102B : Recirculation line
203 : Perforated plate
103A, 103B : Foraminous plate
204 : Molten monomer mixture or prepolymer in the
form of a film, a filament, a droplet or a spray
104A, 104B : Wire
205, 105A, 105B : Gas-feed port
206, 106A, 106B : Vent
207, 107A, 107B : Recirculation pump
208, 108A : Transfer pump
108B : Discharge pump
209, 109A, 109B : Outlet
210 : Main body of free-fall polymerizer
211, lllA : Molten prepolymer
110A, 110B : Main body of wire-wetting fall poly-
merizer
lllB : Molten polymer
(Fig. 4)
301A - 306A : Numerals assigned in connection with
2168630
first vertical agitation type polymerizer
vessel (A)
301B - 306B : Numerals assigned in connection with
first vertical agitation type polymerizer
vessel (B)
301C - 307C : Numerals assigned in connection with
second vertical agitation type polymeriz-
er vessel (C)
101A - lllA : Numerals assigned in connection with
first wire-wetting fall polymerizer
101B - lllB : Numerals assigned in connection with
second wire-wetting fall polymerizer
301A, 301B : Inlet for a starting material
. 301C : Inlet for a prepolymer
302A, 302B, 302C : Vent
303A, 303B : First vertical agitation type poly-
merizer vessels (A) and (B)
303C : Second vertical agitation type polymerizer
vessel (C)
304A, 304B, 304C : Molten prepolymer
305A, 305B, 305C : Outlet
306A, 306B, 306C : Agitator
307C, 309 : Transfer pump
101A, 101B : Inlet for a polymerizing material
102A : Recirculation line
14
2168630
103A, 103B : Foraminous plate
104A, 104B : Wire
105A, 105B : Gas feed port
106A, 106B : Vent
107A : Recirculation pump
108A : Transfer pump
108B : Discharge pump
109A, 109B : Outlet
110A, 110B : Main body of wire-wetting fall poly-
merizer
lllA : Molten Prepolymer
lllB: Molten Polymer
(Fig. 5)
. 401 - 406 : Numerals assigned in connection with hori-
zontal agitation type polymerizer vessel
101 - 111 : Numerals assigned in connection with wire-
wetting fall polymerizer
401 : Horizontal agitation type polymerizer vessel
402 : Inlet for a starting material
403 : Vent
404 : Outlet
405 : Transfer pump
406 : Agitator
101 : Inlet for a polymerizing material
102 : Recirculation line
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103 : Foraminous plate --
104 : Wire
105 : Gas-feed port
106 : Vent
107 : Recirculation pump
108 : Discharge pump
109 : Outlet
110 : Main body of wire-wetting fall polymerizer
111 : Molten polymer
(-Fig. 6)
501 - 511 : Numerals assigned in connection with wall-
wetting fall polymerizer
101A - lllA : Numerals assigned in connection withfirst
wire-wetting fall polymerizer
101B - lllB : Numerals assigned in connection with
second wire-wetting fall polymerizer
501-: Inlet for a starting material
502 : Recirculation line
503 : Overflow port
504 : Wall-wetting fall polymerizer
505 : Film-like prepolymer
506 : Gas feed port
507 : Vent
508 : Recirculation pump
509 : Molten prepolymer
16
2168630
510 : Transfer pump
511 : Outlet
101A, 101B : Inlet for a polymerizing material
102A, 102B : Recirculation line
103A, 103B : Foraminous plate
104A, 104B : Wire
105A, 105B : Gas feed port
106A, 106B : Vent
107A, 107B : Recirculation pump .
-- 108A : Transfer pump
108B : Discharge Pump
109A, 109B : Outlet
110A, 110B : Main body of wire-wetting fall poly-
merizer
lllA : Molten Prepolymer
lllB : Molten Polymer
(Fig. 7)
301A - 306A : Numerals assigned in connection with
first vertical agitation type polymerizer
. vessel (A)
301B - 306B : Numerals assigned in connection with
first vertical agitation type polymerizer
vessel (B)
301C - 307C : Numerals assigned in connection with
second vertical agitation type polymeriz-
2168630
er vessel (C)
201 - 211 : Numerals assigned in connection with free-
fall polymerizer
101 - 111 : Numerals assigned in connection with wire-
wetting fall polymerizer
301A, 301B : Inlet for a starting material
301c : Inlet for a prepolymer
302A, 302B, 302C : Vent
303A, 303B : First vertical agitation type poly--
- merizer vessels (A) and (B)
303C : Second vertical agitation type polymerizer
vessel (C)
304A, 304B, 304C : Molten prepolymer
. 305A, 305B, 305C : Outlet
306A, 306B, 306C : Agitator
307C, 309 : Transfer pump
201 : Inlet for a prepolymer
101 : Inlet for a polymerizing material
202 : Recirculation line
. 203 : Perforated plate
103 : Forminous plate
204 : Molten prepolymer in the form of a film, a
filament, a droplet or a spray
104 : Wire
205, 105 : Gas feed port
18
2168630
206, 106 : Vent
207 : Recirculation pump
208 : Transfer pump
108 : Discharge pump
209, 109 : Outlet
210 : Main body of free-fall polymerizer
110 : Main body of wire-wetting fall polymerizer
211 : Molten prepolymer
111 : Molten polymer .
(-Fig. 8)
301A - 306A : Numerals assigned in connection with
first vertical agitation type polymerizer
vessel (A)
301B - 306B : Numerals assigned in connection with
first vertical agitation type polymerizer
vessel (B)
301C - 307C : Numerals assigned in connection with
second vertical agitation type polymeriz-
er vessel (C)
401 - 406 : Numerals assigned in connection with hori-
zontal agitation type polymerizer
101 - 111 : Numerals assigned in connection with wire-
wetting fall polymerizer
301A, 301B : Inlet for a starting material
301C : Inlet for a prepolymer
2168630
302A, 302B, 302C : Vent --
303A, 303B : First vertical agitation type poly-
merizer vessels (A) and (B)
303C : Second vertical agitation type polymerizer
vessel (C)
304A, 304B, 304C : Molten prepolymer
305A, 305B, 305C : Outlet
306A, 306B, 306C : Agitator
307C, 309 : Transfer pump -
- 401 : Horizontal agitation type polymerizer vessel
402 : Inlet
403 : Vent
404 : Outlet
.405 : Transfer pump
406 : Agitator
101 : Inlet for a polymerizing material
103 : Foraminous plate
104 : Wire
105 : Gas feed port
106 : Vent
108 : Discharge pump
109 : Outlet
110 : Main body of wire-wetting fall polymerizer
111 : Molten polymer
(Fig- 9)
2168630
301A - 306A : Numerals assigned in connection with
first vertical agitation type polymerizer
vessel (A)
301B - 306B : Numerals assigned in connection with
S first vertical agitation type polymerizer
vessel (B)
301C - 307C : Numerals assigned in connection with
second vertical agitation type polymeriz-
er vessel (C) -
501 - 511 : Numerals assigned in connection with wall-
wetting fall polymerizer
101A - lllA : Numerals assigned in connection with
first wire-wetting fall polymerizer
101B - lllB : Numerals assigned in connection with
second wire-wetting fall polymerizer
301A, 301B : Inlet for a starting material
30lC : Inlet for a prepolymer
302A, 302B, 302C : Vent
303A, 303B : First vertical agitation type polymer-
. izer vessels (A) and (B)
303C : Second vertical agitation type polymerizer
vessel (C)
304A, 304B, 304C : Molten prepolymer
305A, 305B, 305C : Outlet
306A, 306B, 306C : Agitator
21
21~8630
307C, 309 : Transfer pump --
501 : Inlet for a prepolymer
502 : Recirculation line
503 : Overflow port
504 : Wall-wetting fall polymerizer
505 : Film-like prepolymer
506 : Gas feed port
507 : Vent
508 : Recirculation pump -
- 509 : Molten prepolymer
510 : Transfer pump
511 : Outlet
101A, 101B : Inlet for a polymerizing material
. 102A : Recirculation line
103A, 103B : Foraminous plate
104A, 104B : Wire
105A, 105B : Gas feed port
106A, 106B : Vent
107A : Recirculation pump
108A : Transfer pump
108B : Discharge pump
109A, 109B : Outlet
110A, 110B : Main body of wire-wetting fall poly-
merizer
lllA : Molten prepolymer
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lllB : Molten polymer --
(Figs. 10 to 12)
103 : Foraminous plate
104 : Wire
121 : Hole of a foraminous plate
122 : Fixation point of wire
123 : Support rod for wire
DETAILED DESCRIPTION OF THE
INVENTION
- Essentially, according to the present invention,
there is provided a novel method for producing an
aromatic polycarbonate, which comprises:
feeding, to a feeding zone having a foraminous
plate, at least one polymerizing material selected from
5 the group consisting of:
a molten monomer mixture of an aromatic dihydroxy
compound and a diaryl carbonate, and
a molten prepolymer obtained by a process compris-
ing reacting an aromatic dihydroxy compound with a
diaryl carbonate,
the foraminous plate having at least one hole, the
feeding zone communicating, through the at least one
hole, with a polymerization zone comprising a wire-
wetting fall polymerization reaction zone, the wire-
wetting fall polymerization reaction zone having at
2168630
least one wire in correspondence with the at least one
hole, the at least one wire being securely held at one
end thereof in an upper end portion of the wire-wetting
fall polymerization reaction zone and extending down-
S wardly through the wire-wetting fall polymerization
reaction zone, so that the polymerizing material fed to
the feeding zone is enabled to pass downwardly through
the foraminous plate and fall along and in contact with
the at least one wire toward the other end of the at
l-east one wire, and
allowing the polymerizing material to pass downwardly
through the foraminous plate and fall along and in
contact with the at least one wire through a wire-
wetting fall polymerization reaction zone, to effect a
wire-wetting fall polymerization of the polymerizing
material,
thereby obtaining a polymer at a bottom of the
polymerization zone comprising the wire-wetting fall
polymerization reaction zone.
For easy understanding of the present invention,
the essential features and various embodiments of the
present invention are enumerated below.
1. A method for producing an aromatic polycarbonate,
which comprises:
feeding, to a feeding zone having a foraminous
24
21C8630
plate, at least one polymerizing material s~lected from
the group consisting of:
a molten monomer mixture of an aromatic dihydroxy
compound and a diaryl carbonate, and
a molten prepolymer obtained by a process compris-
ing reacting an aromatic dihydroxy compound with a
diaryl carbonate,
the foraminous plate having at least one hole, the
feeding zone communicating, through the at least one
hole, with a polymerization zone comprising a wire- -
wetting fall polymerization reaction zone, the wire-
wetting fall polymerization reaction zone having at
least one wire in correspondence with the at least one
hole, the at least one wire being securely held at one
end thereof in an upper end portion of the wire-wetting
fall polymerization reaction zone and extending down-
wardly through the wire-wetting fall polymerization
reaction zone, so that the polymerizing material fed to
the feeding zone is enabled to pass downwardly through
the foraminous plate and fall along and in contact with
the at least one wire toward the other end of the at
least one wire, and
allowing the polymerizing material to pass down-
wardly through the foraminous plate and fall along and
in contact with the at least one wire through a wire-
2168630
wetting fall polymerization reaction zone,-to effect a
wire-wetting fall polymerization of the polymerizing
material,
thereby obtaining a polymer at a bottom of the
polymerization zone comprising the wire-wetting fall
polymerization reaction zone.
2. A method according to item 1 above, which further
comprises recirculating, to the feeding zone having the
foraminous plate, a part or all of the polymer obtained
at the bottom of the polymerization zone, and allowing
the recirculated polymer to pass downwardly through the
foraminous plate and fall along and in contact with the
at least one wire through the wire-wetting fall poly-
. merization reaction zone, thereby increasing the degree
of polymerization of the recirculated polymer to a
predetermined level.3. A method according to item 1 above, wherein the
feeding of the polymerizing material to the feeding
zone having the foraminous plate is continuously con-
ducted, and which method further comprises continuously
conducting a sequence of steps of recirculating, to the
feeding zone having the foraminous plate, a part of the
polymer obtained at the bottom of the polymerization
zone, and allowing an admixture of the continuously fed
polymerizing material and the recirculated polymer to
2168630
pass downwardly through the foraminous plate and fall
along and in contact with the at least one wire through
the wire-wetting fall polymerization reaction zone,
thereby continuously effecting a wire-wetting fall
polymerization of the admixture, while continuously
withdrawing the remainder of the polymer obtained at
the bottom of the polymerization zone.
4. A method according to item 1 above, wherein the
polymerizing material is the molten prepoIymer.
5. A method according to item 4 above, wherein the -
molten prepolymer is a molten second prepolymer which
has been obtained by a process selected from the group
consisting of:
(a) a free-fall polymerization process comprising
introducing, to an introduction zone having a perforat-
ed plate, at least one starting material selected from
the group consisting of:
a monomer mixture of an aromatic dihydroxy com-
pound and a diaryl carbonate, and
a first prepolymer obtained by reacting an aromat-
ic dihydroxy compound with a diaryl carbonate, and
allowing the starting material to pass downwardly
through the perforated plate and fall freely through a
free-fall polymerization reaction zone, thereby effect-
ing a free-fall polymerization of the starting material
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during the free-fall thereof,
(b) an agitation polymerization process comprising
agitating at least one starting material in a molten
state in an agitation type polymerizer vessel, wherein
the starting material is as defined above, thereby
effecting an agitation polymerization of the starting
material, and
(c) a thin film-state polymerization process
comprising subjecting at least one starting material in
a-molten state to a thin film-forming treatment to form
a thin film of the starting material, wherein the
starting material is as defined above, thereby effect-
ing a thin film-state polymerization of the starting
material while allowing the thin film to maintain a
thin film-state thereof, and
wherein the molten second prepolymer as the poly-
merizing material is subjected to the wire-wetting fall
polymerization to obtain the polymer at the bottom of
the polymerization zone.
6, A method according to item 5 above, which further
comprises recirculating to the feeding zone a part or
all of the polymer obtained at the bottom of the poly-
merization zone, and allowing the recirculated polymer
to pass downwardly through the foraminous plate and
fall along and in contact with the at least one wire
28
2168630
through the wire-wetting fall polymerization reaction
zone, thereby increasing the degree of polymerization
of the recirculated polymer to a predetermined level.
7. A method according to item 5 above, wherein, in the
wire-wetting fall polymerization of the second prepoly-
mer, the feeding of the second prepolymer to the feed-
ing zone having the foraminous plate is continuously
conducted, and which method further comprises continu-
ously conducting a sequence of steps of recirculating
to the feeding zone a part of the polymer obtained at
the bottom of the polymerization zone, and allowing an
admixture of the continuously fed second prepolymer in
the molten state and the recirculated polymer to pass
downwardly through the foraminous plate and fall along
and in contact with the at least one wire through the
wire-wetting fall polymerization reaction zone, thereby
continuously effecting a wire-wetting fall polymeriza-
tion of the admixture, while continuously withdrawing
the remainder of the polymer obtained at the bottom of
the polymerization zone.
8. A method according to item 4 above, where~in the
molten prepolymer is a molten third prepolymer which
has been obtained by a process selected from the group
consisting of:
(d) an agitation and free-fall polymerization
29
2168630
process comprising:
agitating a starting material in a molten
state in an agitation type polymerizer vessel, the
starting material being at least one member selected
from the group consisting of:
a monomer mixture of an aromatic dihydroxy com-
pound and a diaryl carbonate, and
a first prepolymer obtained by reacting an aromat-
ic dihydroxy compound with a diaryl carbonate, -
- thereby effecting an agitation polymerization of
the starting material to obtain a second prepolymer;
and
introducing the second prepolymer in a molten
. state to an introduction zone having a perforated
plate, and allowing the second prepolymer to pass
downwardly through the perforated plate and fall freely
through a free-fall polymerization reaction zone,
thereby effecting a free-fall polymerization of the
second prepolymer during the free-fall thereof, and
. (e) an agitation and thin film-state polymeriza-
tion process comprising:
agitating a starting material in a molten
state in an agitation type polymerizer vessel, wherein
the starting material is as defined above, thereby
effecting an agitation polymerization of the starting
2168630
material to obtain a second prepolymer; and-
subjecting the second prepolymer in a molten state
to a thin film-forming treatment to form a thin film of
the starting material, wherein the starting material is
as defined above, thereby effecting a thin film-state
polymerization of the second prepolymer while allowing
the thin film to maintain a thin film-state thereof,
and
wherein the molten third prepolymer as the poly-
merizing material is subjected to the wire-wetting fall
polymerization to obtain the polymer at the bottom of
the polymerization zone.
9. A method according to item 8 above, which further
comprises recirculating to the feeding zone a part or
all of the polymer obtained at the bottom of the poly-
merization zone, and allowing the recirculated polymer
to pass downwardly through the foraminous plate and
fall along and in contact with the at least one wire
through the wire-wetting fall polymerization reaction
zone, thereby increasing the degree of polymerization
of the recirculated polymer to a predetermined level.
10. A method according to item 8 above, wherein, in
the wire-wetting fall polymerization of the third
prepolymer, the feeding of the third prepolymer to the
feeding zone having the foraminous plate is continuous-
2168630
ly conducted, and which method further comprises con-
tinuously conducting a sequence of steps of recirculat-
ing to the feeding zone a part of the polymer obtained
at the bottom of the polymerization zone, and allowing
an admixture of the continuously fed third prepolymer
in the molten state and the recirculated polymer to
pass downwardly through the foraminous plate and fall
along and in contact with the at least one wire through
the wire-wetting fall polymerization reaction zone, ,
thereby continuously effecting a wire-wetting fall''
polymerization of the admixture, while continuously
withdrawing the remainder of the polymer obtained at
the bottom of the polymerization zone.
11. A method according to item 5 or 8 above, wherein
the agitation polymerization of the starting material
is effected using at least one member selected from the
group consisting of a vertical agitation type polymer-
izer vessel having agitating elements rotating on a
vertically extending axis and a horizontal agitation
ty,pe polymerizer vessel having agitating elements
rotating on a horizontally extending axis.
12. A method according to item 11 above, wherein the
agitation polymerization of the starting material is
effected using both of the vertical agitation type
polymerizer vessel and the horizontal agitation type
2168630
.
polymerizer vessel in this order. --
13. A method according to any one of items l to 10
above, wherein the wire-wetting fall is conducted
through a distance of 0.3 m or more.
14. A method according to any one of items 1 to 10
above, wherein the polymerizing material is allowed to
pass downwardly through the foraminous plate at a flow
rate in the range of from 10-2 to 102 liters/hr per
hole. -
15. A method according to item 13 above, wherein the
polymerizing material is allowed to pass downwardlythrough the foraminous plate at a flow rate in the
range of from 10-2 to 102 liters/hr per hole.
16. A method according to any one of items 1 to 10
above, wherein the polymerization zone comprising the
wire-wetting fall polymerization reaction zone further
comprises a free-fall polymerization reaction zone on
at least one side selected from an upstream side and a
downstream side relative to the wire-wetting fall
polymerization reaction zone in contiguous relation-
ship.
As mentioned above, a number of polymerizershaving no rotary driving parts in their respective main
bodies are known for use in producing resins other than
polycarbonates. In this connection, it should be noted
2168630
that there is a large difference between th~ melt
polycondensation reaction for producing aromatic poly-
carbonates and that for producing polyesters and polya-
mides, so that it is difficult to apply a polymerizer
designed for use in producing polyesters and polyamides
to the production of aromatic polycarbonates. The
major differences between aromatic polycarbonates and
both polyesters and polyamides are as follows: First,
the melt viscosity, which is an important factor in
designing a polymerizer for melt polycondensation of
aromatic polycarbonates, is extremely high as compared
to that of polyesters and polyamides. Specifically, at
the temperatures of polymerization, the melt viscosity
of both polyamides and polyesters at a later stage of
polymerization is usually from several hundred to
several thousand poises and is unlikely to rise to a
level of 3000 poises or more, whereas the melt viscosi-
ty of aromatic polycarbonates at a later stage of
polymerization reaches a level as high as tens of
thousands of poises. Second, the melt polycondensa-
tions of polyamides, polyesters and aromatic polycar-
bonates are all equilibrium reactions, but the reac-
tions for these polymers are largely different in
equilibrium constant. Generally, the equilibrium
constant of the reaction for polyamides is on the ordér
34
2168630
of 102 and that for polyesters is approximately 1,
whereas the equilibrium constant of the reaction for
aromatic polycarbonates is very small and on the order
of 10-1. The smaller the equilibrium constant, the
more difficult the polymerization reaction, so that the
reaction does not proceed unless by-products are more
efficiently removed from the reaction system. There-
fore, in the polymerization of aromatic polycarbonates,
the by-products must be removed from the reaction
system far more efficiently than in the polymerization
of polyamides and polyesters. However, efficient
removal of by-products is very difficult in the produc-
tion of aromatic polycarbonates since aromatic polycar-
bonates have a very high melt viscosity, as mentioned
above.
However, it has surprisingly been found that when
a wire-wetting fall polymerization technique is applied
to production of aromatic polycarbonates, high quality
aromatic polycarbonates can be produced with great
advantages, without causing the above-mentioned prob-
lems accompanying the operation of fall polymerization
of polyamides and polyesters. In other words, by the
present invention, high quality aromatic polycarbonates
can be stably produced since a polymerizing material
which falls along and in contact with a wire does not
, 2168630
suffer breakage during the wire-wetting fall, and the
quality of the resultant polymer becomes uniform.
Namely, since no accumulation of low molecular weight
polycondensate occurs on a spinneret, a polymerizing
material can be injected, or allowed to fall, straight
down without hindrance, and there is no need to halt
the operation to replace smudged spinnerets with fresh
ones. Therefore, the operation can be stably carried
out for a very long period of time.
- The reason for such a difference in behavior
between the wire-wetting fall polymerization of aromat-
ic polycarbonates and the fall polymerization of pol-
yesters and polyamides has not yet been elucidated.
With respect to the reason why spinnerets do not at all
suffer from accumulation of a low molecular weight
polycondensate, it is presumed that by-produced phenol
effectively washes away the low molecular weight poly-
condensate accumulated on the spinneret during the
polymerization of aromatic polycarbonates, fundamental-
ly differing from the polymerization of polyamides orpolyesters wherein by-products are water and ethylene
glycol. Such an advantageous effect of the by-produced
phenol on the wire-wetting fall polymerization of
aromatic polycarbonates could not be expected from the
polymerization of polyesters and polyamides at all.
36
2168630
The wire-wetting fall polymerization method of the
present invention using a foraminous plate and a wire
does not require a polymerizer which has a rotary
driving part which is exposed to a gaseous phase during
the reaction, so that, with respect to polymerization
apparatus for practicing a wire-wetting fall polymeri-
zation method, excellent sealing can be provided even
under high vacuum, and maintenance of the apparatus is
easy. Furthermore, colorless, transparent and high
quality aromatic polycarbonate can be easily produced
by the method of the present invention. That is, the
method of the present invention for producing an aro-
matic polycarbonate solves all of the difficult prob-
lems mentioned above which accompany conventional
methods for melt polycondensation of an aromatic poly-
carbonate.
Hereinbelow, the present invention will be de-
scribed in more detail.
In the present invention, the terminology "aromat-
ic dihydroxy compound" means a compound représented by
the following formula:
HO-Ar-OH
wherein Ar represents a divalent aromatic group.
Preferred examples of divalent aromatic groups as
Ar include a group represented by the following formu-
37
2168630
la: -
--Arl--Y--Ar2_
wherein each of Ar1 and Ar2 independently
represents a divalent carbocyclic or hetero-
cyclic aromatic group having from 5 to 70
carbon atoms, and Y represents a divalent
alkane group having from 1 to 30 carbon
atoms.
In divalent aromatic groups as Ar1 and Ar2, at
10 least one hydrogen atom may be substituted with a
substituent which does not adversely affect the reac-
tion, such as 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 groùp, a phenoxy group,
a vinyl group, a cyano group, an ester group, an amide
group and a nitro group.
Illustrative examples of heterocyclic aromatic
groups include an aromatic group having at least one
hetero atom, such as a nitrogen atom, an oxygen atom or
0 a sulfur atom.
Examples of divalent aromatic groups as Ar1 and
Ar2 include an unsubstituted or substituted phenylene
group, an unsubstituted or substituted biphenylene
group and an unsubstituted or substituted pyridylene
5 group. Substituents for Ar1 and Ar2 are as described
38
2168630
above.
Examples of divalent alkane groups as Y include
organic groups respectively represented by the follow-
ing formulae:
R' R~ R3 Rs
- C - , - C - C - and ~ C ~ X
wherein each of R1, R2, R3 and R4 independ-
10 . ently 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-forming carbon atoms, a carbocyclic
aromatic group having from 5 to 10 ring-
forming carbon atoms and a carbocyclic aral-
kyl group having from 6 to 10 ring-forming
carbon atoms; k represents an integer of from
3 to 11; each X represents a carbon atom and
. has R5 and R6 bonded thereto; each R5 inde-
pendently represents a hydrogen atom or an
alkyl group having from 1 to 6 carbon atoms,
and each R6 independently represents a hydro-
gen atom or an alkyl group having from 1 to 6
carbon atoms, wherein R5 and R6 are the same
39
2168630
or different; .-
wherein at least one hydrogen atom of each of
Rl / R2 r R3, R4, R5 and R6 may be substituted
with a substituent which does not adversely
affect the reaction, such as 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 group and a nitro group.
Specific examples of divalent aromatic groups as
Ar include groups respectively represented by the
following formulae:
2168630
(R i)n ( R ' )m ~
s ; , ~, ~ ; n
5 ;1'~ r~
(R a)n
~ ~ and ~ ~ H ~-C H
41
. 2168630
wherein each of R7 and R8 independently
represents 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-forming carbon atoms, or a
phenyl group; each of m and n independently
represents an integer of from 1 to 4, with
the proviso that when m is an integer of from
- 2 to 4, R7's are the same or different, and
when n is an integer of from 2 to 4, R8's are
the same or different.
Further, examples of divalent aromatic groups as
Ar also include those which are represented ~y the
following formula:
--Arl--Z--Ar2_
wherein Arl and Ar2 are as defined above; and
Z represents a single bond or a divalent
group, such as -O-, -CO-, -S-, -SO2, -SO-,
. -COO-, or -CON(Rl)-, wherein Rl is as defined
above.
Examples of such divalent aromatic groups as Ar
include groups respectively represented by the follow-
ing formulae:
42
2168630
( R ~)m ( R 8)n ( R 7)m ( R E)n
( R ~)m ( R ~)n ( R 7)m ( R 8)n
~ S ~ , ~,\~S 0~
Io ( R 7)m ( R ~)n ( R ~)m ( R 8)n
~S O2~ , ~ C 0~
( R ~)m ( R 8)n ( R ~)m ~ ( R 8)n
~C ONH ~ ,~C O O ~,
(R 7)m C H 3 (R 8)n O O (R ')m C H 3 (R 8)n
~"` ¢ '~Oe~CO~¢~,
CH3 CH3
( R 7)m ( R ')m ( R 8)n
and ~
wherein R7, R8, m and n are as defined above.
In the method of the present invention, the aro-
43
2168630
matic dihydroxy compounds can be used individually or
in combination. Representative examples of aromatic
dihydroxy compounds include bisphenol A.
The diaryl carbonate used in the present invention
is represented by the following formula:
o
Ar3-30C0-Ar4
wherein each of Ar3 and Ar4 independently
represents a monovalent aromatic group.
Each of Ar3 and Ar4 independently represents a
monovalent carbocyclic or heterocyclic aromatic group.
At least one hydrogen atom of each of Ar3 and Ar4 may
be substituted with a substituent which does not ad-
versely affect the reaction, such as a halogen atom, analkyl 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 group and a nitro group. Ar3 and Ar4
are the same or different.
Representative examples of monovalent aromatic
groups Ar3 and Ar4 include a phenyl group, a naphthyl
group, a biphenyl group and a pyridyl group.
Preferred examples of monovalent aromatic groups
as Ar3 and Ar4 are those respectively represented by
44
2168630
the following formulae:
, ~ - C H J r ~ ~ C - C ~ J
C H 3 C H 3 C H 3
C H J and ~ I - C H 2 - C - C H 3
Representative examples of diaryl carbonates
include a substituted or unsubstituted diphenyl carbon-
ate compound represented by the following formula:
(R9)p 0 (R ')q
~ O 11 0~
. wherein each of R9 and R10 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-
forming carbon atoms or a phenyl group; each
2168630
of p and q independently represents an-inte-
ger of from 1 to 5, with the proviso that
when p is an integer of 2 or more, R9's are
the same or different, and when q is an
integer of 2 or more, R10's are the same or
different.
Of these diphenyl carbonate compounds, preferred
are diaryl carbonates having a symmetrical configura-
tion, such as (unsubstituted) diphenyl carbonate,
ditolyl carbonate, and a diphenyl carbonate substituted
with a lower alkyl group, e.g., di-t-butylphenyl car-
bonate. Particularly preferred is diphenyl carbonate,
which is the diaryl carbonate having the simplest
structure.
These diaryl carbonates may be used individually
or in combination.
The ratio in which the aromatic dihydroxy compound
and the diaryl carbonate are used (i.e. a charging
ratio) may vary depending on the types of the aromatic
dihydroxy compound and diaryl carbonate employed, the
polymerization temperature and other polymerization
conditions. The diaryl carbonate is generally used in
an amount of from 0.9 to 2.5 moles, preferably from
0.95 to 2.0 moles, more preferably from 0.98 to 1.5
moles, per mole of the aromatic dihydroxy compound.
46
2168630
The number average molecular weight of the aromat-
ic polycarbonate obtained according to the method of
the present invention is generally from 500 to 100,000,
preferably from 500 to 30,000.
In the present invention, the term "molten monomer
mixture of an aromatic dihydroxy compound and a diaryl
carbonate" means a homogeneous mixture of the monomers
which is obtained by mixing the aromatic dihydroxy
compound and the diaryl carbonate while heating. The.
molten monomer mixture can be obtained by mi ~i ng the
aromatic dihydroxy compound and the diaryl carbonate
while heating at a temperature in the range of from
150 C to 200 C. In the present invention, the term
"molten prepolymer" means a polycondensate, which is
obtained by a process comprising reacting an aromatic
dihydroxy compound with a diaryl carbonate, and has a
lower molecular weight than a final aromatic polycar-
bonate to be produced by the method of the present
invention. The range of the molecular weight of the
molten prepolymer to be used in the present invention
varies depending on the molecular weight of a final
aromatic polycarbonate to be produced. For example,
when it is intended to obtain an aromatic polycarbonate
having a number average molecular weight of 10,000, the
number average molecular weight range of the molten
2168630
prepolymer is less than 10,000; and when it-is intended
to obtain an aromatic polycarbonate having a number
average molecular weight of 20,000, the number average
molecular weight range of the molten prepolymer is less
than 20,000.
In the method of the present invention, a polymer-
izing material [which is at least one member selected
from the group consisting of a) a molten monomer mix-
ture of an aromatic dihydroxy compound and a diaryl -
carbonate, and b) a molten prepolymer obtained by a -
process comprising reacting an aromatic dihydroxy
compound with a diaryl carbonate] is allowed to pass
downwardly through a foraminous plate and fall along
and in contact with a wire through a wire-wetting fall
polymerization reaction zone, thereby effecting poly-
merization of the polymerizing material during the
wire-wetting fall thereof.
The foraminous plate to be used in the present
invention has at least one hole. The feeding zone in
the wire-wettlng fall polymerizer communicates, through
the hole, with a polymerization zone comprising a
wire-wetting fall polymerization reaction zone. The
wire-wetting fall polymerization reaction zone has at
least one wire in correspondence with the hole, and the
wire is securely held at one end thereof in an upper
48
2168630
end portion of the wire-wetting fall polymerization
reaction zone and extends downwardly through the wire-
wetting fall polymerization reaction zone.
There is no particular limitation with respect to
the shape of holes of the foraminous plate to be used
in the method of the present invention. Generally, the
morphology of a hole is selected from a circle, an
ellipse, a triangle, a slit, a polygon, a star and the
like. The area of each hole of the foraminous plate is
usually from 0.01 to 100 cm2, preferably from 0.05-to
10 cm2, more preferably from 0.1 to 5 cm2. The forami-
nous plate may have a nozzle or the like connected
thereto. The distance between adjacent holes is gener-
ally from 1 to 500 mm, preferably from 5 to 100 mm, as
measured between the centers of the adjacent holes.
The term "wire" used herein means a metallic
material which has a small value in respect of the
ratio of the average perimeter of the cross-section of
the metallic material to the length of the metallic
material as measured in the direction perpendicular to
the cross-section. There is no particular limitation
with respect to the above ratio, but it is usually from
1/2 to 1/1,000,000, preferably from 1/5 to 500,000,
more preferably from 1/10 to 50,000.
There is also no particular limitation to the
49
2168630
morphology of the cross-section of the wire. Generally,
the morphology of the cross-section of the wire is
selected from a circle, an ellipse, a triangle, a
quadrangle, a polygon, a star and the like. The mor-
S phology of the cross-section of the wire may be uniform
or varying along the length of the wire. The wire may
be hollow. The wire may be made of a single strand, or
made of a plurality of strands, wherein, for example,
the strands are twisted together or fabricated into a
chain, or wherein the strands are hung with a space
between mutually adjacent ones of the strands, the
space being surely held by means a linear or a platy
spacer fixedly connecting thereto the strands at their
respective intermediate points, so that the strands are
prevented from contacting therebetween. The surface of
the wire may be smooth or jagged or may have projec-
tions locally. There is no particular limitation on
the type of the metallic material of the wire, but the
metallic material is generally selected from stainless
steel, carbon steel, Hastelloy, nickel, titanium,
chromium and other alloys. The surface of the wire
may, if desired, be treated with, for example, plating,
lining, passivation, or washing with an acid or phenol.
In the present invention, generally a single wire
corresponds to a single hole of the foraminous plate.
-- 2168630
However, if desired, a single wire may correspond to a
plurality of holes, so that a plurality of streams of
polymerizing material which have been allowed to pass
through a plurality of holes, respectively, are joined
S into a single stream and allowed to fall along and in
contact with a single wire. Alternatively, a plurality
of wires may correspond to a single hole, so that a
single stream of polymerizing material which has been
allowed to pass through a single hole, may be separated
- into a plurality of streams, so that the plurality of
streams are allowed to fall along and in contact with a
plurality of wires, respectively.
With respect to the positional relationship be-
tween the at least one wire and the foraminous plate,
and to the positional relationship between the at least
one wire and the at least one hole of the foraminous
plate, there is no particular limitation as long as a
polymerizing material fed to the feeding zone is ena-
bled to pass downwardly through the foraminous plate
and fall along and in contact with the at least one
wire toward the lower end of the at least one wire.
The wire and foraminous plate either may be or may not
be in contact with each other.
Figs. 10 to 12 respectively show three examples of
manners in which the wire is provided in correspondence
2168630
with the hole of the foraminous plate.
In Fig. 10, the upper end of wire 104 is secured
to support rod 123 provided above foraminous plate 103,
and wire 104 extends downwardly through hole 121 of
foraminous plate 103. Wire 104 and support rod 123 are
secured to each other at fixation point 122. It is
possible that support rod 123 be omitted and the upper
end of wire 104 be connected, for example, to the upper
inner wall surface (not shown) of the wire-wetting f?11
polymerizer.
In Fig. 11, the upper end of wire 104 is secured
to the upper circumferential edge of hole 121 of foram-
inous plate 103 at fixation point 122, and wire 104
extends downwardly through hole 121 of foraminous plate
103.
In Fig. 12, the upper end of wire 104 is secured
to the lower surface of foraminous plate 103 at fixa-
tion point 122, and wire 104 extends downwardly from
the lower surface of foraminous plate 103.
Alternatively, the upper end of wire 104 may be
positioned below hole 121 of foraminous plate 103. In
such a case, a polymerizing material which has passed
downwardly through foraminous plate 103 may freely fall
before falling along and in contact with wire 104
toward the lower end of wire 104. This embodiment (in
52
2168630
which a wire-wetting fall is immediately preceded by a
free fall) is enabled, for example, by a method in
which a wire is attached to a support rod as shown in
Fig. 10, and support rod 123 having wire 104 attached
thereto is provided not at a position above foraminous
plate 103 as shown in Fig. 10, but at a position below
foraminous plate 103.
Further, the wire-wetting fall polymerization may
be followed by a free-fall polymerization wherein a .
wire-wetting fall polymerized product is consecutively
allowed to fall freely through a free-fall polymeriza-
tion reaction zone after leaving the lower end of the
wire, the free-fall polymerization reaction zone being
provided downstream of and contiguously to the wire-
wetting fall polymerization reaction zone.
Examples of methods for allowing a polymerizingmaterial to pass through the foraminous plate and fall
along and in contact with the wire, include a method in
which only gravitational force is utilized, and a
method in which the polymerizing material is pressur-
ized by means of a pump or the like.
With respect to the number of holes in the forami-
nous plate, there is no particular limitation, but the
number of holes may vary depending on conditions, such
as the reaction temperature and pressure, the amount of
,2168630
catalyst, and the range of molecular weight of polycar-
bonate to be produced. For example, when a polymer is
to be produced at a rate of 100 kg/hr, usually 10 to
105 holes are necessary. A distance through which the
wire-wetting fall of the polymerizing material is
conducted is preferably from 0.3 m or more, more pref-
erably from 0.3 to 50 m, still more preferably from 0.5
to 20 m.
In the present invention, as described above, the
polymerization zone comprising the wire-wetting fall
polymerization reaction zone may further comprise a
free-fall polymerization reaction zone on at least one
side selected from an upstream side and a downstream
side relative to the wire-wetting fall polymerization
reaction zone in contiguous relationship. With respect
to the distance through which such a free-fall is
conducted, there is no particular limitation, but the
free-fall distance is generally from 0.5 cm to 10 m on
an upstream and/or a downstream side relative to the
wire-wetting fall polymerization.
A flow rate at which the polymerizing material
passes through the holes of the foraminous plate may
vary depending on the molecular weight of the polymer-
izing material. ~he flow rate per hole is preferably
from 10-2 to 102 liters/hr, more preferably from 0.1 to
54
2168630
50 liters/ hr. When the flow rate is higher than the
above range, the polymerization rate tends to be de-
creased, whereas when the flow rate is lower than the
above range, the productivity tends to be lowered.
The wire-wetting fall time is not particularly
limited, but is generally from 1 second to 100 hours.
In the present invention, a polymer obtained by
the wire-wetting fall polymerization can be withdrawn,
as such, from the polymerizer, but it is preferred that
the polymer be recirculated to the feeding zone having
the foraminous plate for further wire-wetting fall
polymerization. In this case, residence time of poly-
mer in a reservoir portion at the bottom of the wire-
wetting fall polymerization reaction zone or in a
recirculation line can be prolonged according to the
time necessary for polycondensation reaction. When the
obtained polymer is recirculated and subjected to
further wire-wetting fall polymerization, a renewed
liquid surface area formed per unit time becomes large,
so that a desired molecular weight can be easily
achieved.
Preferred examples of embodiments of the method of
the present invention include a method wherein the
feeding of the polymerizing material (molten monomer
mixture and/or molten prepolymer) to the feeding zone
2168630
having the foraminous plate is continuously conducted,
and which method further comprises continuously con-
ducting a sequence of steps of recirculating, to the
feeding zone (having the foraminous plate), a part of
the polymer obtained at the bottom of the wire-wetting
fall polymerization reaction zone, and allowing an
admixture of the continuously fed polymerizing material
and the recirculated polymer to pass downwardly through
the foraminous plate and fall along and in contact with
the wire through the wire-wetting fall polymerizati-on
reaction zone, thereby continuously effecting a wire-
wetting fall polymerization of the admixture during the
wire-wetting fall thereof, while continuously withdraw-
ing the remainder of the polymer obtained at the bottom
of the wire-wetting fall polymerization reaction zone.
According to this embodlment, polymerization can be
carried out stably for a prolonged period of time
without an accumulation of low molecular weight poly-
condensate and the like on a foraminous plate. This is
one of the great advantages of the present invention.
In the present invention, the reaction temperature
for reacting the aromatic dihydroxy compound with the
diaryl carbonate is generally in the range of from 50
to 350 C, preferably from 100 to 290 C.
As the reaction proceeds, an aromatic monohydroxy
56
2168630
compound is by-produced. By removing the aromatic
monohydroxy compound from the reaction system, the
reaction rate can be increased. Therefore, in the
method of the present invention, it is preferable to
employ a method in which an inert gas which does not
adversely affect the reaction, such as nitrogen, argon,
helium, carbon dioxide and a lower hydrocarbon gas, is
introduced so that the by-produced aromatic monohydroxy
compound is entrained by the inert gas, and the inert
gas entraining the aromatic monohydroxy compound is -
withdrawn to remove the aromatic monohydroxy compound,
or a method in which the reaction is carried out under
reduced pressure. The above two methods can be used
individually or in combination. The preferred reaction
pressure may vary depending on the type of the aromatic
polycarbonate to be produced, the molecular weight of
the molten monomer mixture or molten prepolymer, and
the polymerization temperature. For example, in the
case of a reaction in which an aromatic polycarbonate
is produced from bisphenol A and diphenyl carbonate,
when the number average molecular weight of the molten
monomer mixture or molten prepolymer is less than
1,000, the reaction pressure is preferably from 50 mmHg
to atmospheric pressure. In this case, when the number
average molecular weight is from 1,000 to 2,000, the
~2168630
reaction pressure is preferably from 3 to 80 mmHg.
When the number average molecular weight is greater
than 2,000, the reaction pressure is preferably 10 mmHg
or less, more preferably 5 mmHg or less.
It is particularly preferred that the polymeriza-
tion be carried out under reduced pressure while intro-
ducing an inert gas as mentioned above. By this meth-
od, a high degree of polymerization can efficiently be
achieved without causing problems, such as mutual
contact of adjacent wires due to turbulence of gas
flow.
A melt polycondensation reaction can be carried
out in the absence of a catalyst. However, if it is
desired to accelerate the polymerization, the polymeri-
zation can be effectd in the presence of a catalyst.
The polymerization catalysts which are customarily used
in the art can be used without particular limitation.
Examples of such catalysts include hydroxides of an
alkali metal and of an alkaline earth metal, such as
lithium hydroxide, sodium hydroxide, potassium hydrox-
ide and calcium hydroxide; alkali metal salts of,
alkaline earth metal salts of and quaternary ammonium
salts of boron hydride and of aluminum hydride, such as
lithium aluminum hydride, sodium boron hydride and
tetramethyl ammonium boron hydride; hydrides of an
58
.2168630
alkali and of an alkaline earth metal, such-as lithium
hydride, sodium hydride and calcium hydride; alkoxides
of an alkali metal and of an alkaline earth metal,
such as lithium methoxide, sodium ethoxide and calcium
methoxide; aryloxides of an alkali metal and of an
alkaline earth metal, such as lithium phenoxide, sodium
phenoxide, magnesium phenoxide, LiO-Ar-OLi wherein Ar
represents an aryl group, and NaO-Ar-ONa wherein Ar is
as defined above; organic acid salts of an alkali metal
and of an alkaline earth metal, such as lithium ace-.
tate, calcium acetate and sodium benzoate; zinc com-
pounds, such as zinc oxide, zinc acetate and zinc
phenoxide; boron compounds, such as boron oxide, boric
acid, sodium borate, trimethyl borate, tributyl borate,
triphenyl borate, ammonium borates represented by the
formula: (R1 R2 R3 R4)NB(Rl R2 R3 R4), and phosphonium
borates represented by the formula:
(Rl R2 R3 R4~ps(Rl R2 R3 R4), wherein Rl, R2, R3 and R4
are as defined above; silicon compounds, such as sili-
con oxide, sodium silicate, tetraalkylsilicon, tetraa-
rylsilicon and diphenyl-ethyl-ethoxysilicon; germanium
compounds, such as germanium oxide, germanium tetra-
chloride, germanium ethoxide and germanium phenoxide;
tin compounds, such as tin oxide, dialkyltin oxide,
dialkyltin carboxylate, tin acetate, tin compounds
59
2168630
.
having an alkoxy group or aryloxy group bonded to tin,
such as ethyltin tributoxide, and organotin compounds;
lead compounds, such as lead oxide, lead acetate, lead
carbonate, basic lead carbonate, and alkoxides and
s 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, manga-
nese carbonate and manganese borate; titanium com-
pounds, such as titanium oxide and titanium alkoxides
and titanium aryloxide; and zirconium compounds, such
as zirconium acetate, zirconium oxide, zirconium alkox-
ide, zirconium aryloxide and zirconium acetylacetone.
The catalysts can be used individually or in
combination. The amount of the catalysts to be used is
generally in the range of from 10-8 to 1 % by weight,
preferably from 10-7 to 10~1 ~ by weight, based on the
weight of the aromatic dihydroxy compound.
Preferred modes of the method of the present
invention in which a wire-wetting fall polymerizer is
used are explained hereinbelow, referring to the accom-
panying drawings.
Figs. 1 and 2 show two forms of polymerization
apparatus (each cont~ining a wire-wetting fall polymer-
2168630
izer) usable for carrying out the method of the present
invention. When the polymerization apparatus of Fig. 1
is used, a polymerizing material [which is at least one
material selected from the group consisting of a) a
molten monomer mixture of an aromatic dihydroxy com-
pound and a diaryl carbonate, and b) a molten prepoly-
mer obtained by a process comprising reacting an aro-
matic dihydroxy compound with a diaryl carbonate] is
fed through inlet 101 and fed to a feeding zone having
foraminous plate 103, and allowed to pass downwardly
through foraminous plate 103 and fall along and in
contact with wire 104 through a wire-wetting fall
polymerization reaction zone in polymerizer 110. The
internal pressure of wire-wetting fall polymerizer 110
is controlled to a predetermined value. An aromatic
monohydroxy compound and the like evaporated from the
polymerization reaction system and an inert gas, such
as nitrogen, which is optionally fed from gas feed port
105, are discharged through vent 106. The resultant
polymer obtained at the bottom of the wire-wetting fall
polymerization reaction zone is withdrawn through
outlet 109 by means of discharge pump 108. The main
body of free-fall polymerizer 110 and the like are
heated to and kept at an elevated temperature by means
of a heater and a jacket.
61
2168630
When a polymerization apparatus of Fig. 2 is used,
a polymerizing material (which is as defined above) is
fed through inlet 101 to recirculation line 102 and fed
to a feeding zone having foraminous plate 103, and
allowed to pass downwardly through foraminous plate 103
and fall along and in contact with wire 104 through a
wire-wetting fall polymerization reaction zone in
wire-wetting fall polymerizer 110. The internal pres-
sure of wire-wetting fall polymerizer 110 is maintained
at a predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed
from gas feed port 105, are discharged through vent
106. The resultant polymer obtained at the bottom of
the wire-wetting fall polymerization reaction zone is
recirculated through recirculation line 102 (having
recirculation pump 107) to the feeding zone having
foraminous plate 103, and allowed to pass through
foraminous plate 103 and fall along and in contact with
wire 104 through the wire-wetting fall polymerization
reaction zone in polymerizer 110, thereby increasing
the degree of polymerization of the recirculated poly-
mer during the wire-wetting fall thereof. After the
degree of polymerization has reached a predetermined
level, the polymer is withdrawn through outlet 109 by
2168630
means of discharge pump 108. The main body of wire-
wetting fall polymerizer 110, recirculation line 102
and the like are heated to and kept at an elevated
temperature by means of a heater and a jacket.
When wire-wetting fall polymerizer 110 of Fig. 2
is used for batchwise polymerization, all of the poly-
merizing material selected from the molten monomer
mixture and the molten prepolymer is fed through inlet
101 at the start of the operation at a time, and poly-
merization is carried out in a closed system while
recirculating until a polymer having a predetermined
degree of polymerization is obtained. The obtained
polymer is withdrawn through outlet 109. When wire-
wetting fall polymerizer 110 of Fig. 2 is used for
continuous polymerization, the polymerizing material is
continuously fed through inlet 101 to conduct wire-
wetting fall polymerization, while the resultant poly-
- mer (having a predetermined molecular weight) is con-
tinuously withdrawn through outlet 109 at a controlled
rate such that a predetermined amount of molten poly-
condensate mixture is present in the polymerizer.
A polymerizer to be used in the present invention
may be equipped with an agitator at the bottom, but
such an agitator is not essential. Therefore, it is
possible to employ a wire-wetting fall polymerizer
63
2168630
which does not have a rotary driving part in a main
body thereof and hence it is possible to carry out
polymerization under tightly sealed conditions even
under high vacuum. The recirculation pump in the
recirculation line has a rotary driving part, but the
rotary driving part of the recirculation pump in the
recirculation line is highly sealed, thus differing
from a rotary driving part as provided in the main body
of a polymerizer, because the recirculation pump is
submerged below a liquid head of molten condensate-
mixture accumulated at the bottom of the main body.
The method of the present invention can be prac-
ticed using a single polymerizer, but, if desired, two
or more polymerizers can be used. Moreover, the inte-
rior of a single polymerizer may be partitioned verti-
cally or horizontally into a plurality of compartments
so that the compartments can be used as multiple poly-
merizers.
In the present invention, it is possible to carry
out the entire process of polymerizing a molten monomer
mixture of an aromatic dihydroxy compound and a diaryl
carbonate for obtaining a final aromatic polycarbonate
having a predetermined molecular weight by only a
wire-wetting fall polymerization using a foraminous
plate and a wire. But it is also possible to combine
64
2168630
the wire-wetting fall polymerization with other poly-
merization methods, such as a free-fall polymerization,
a thin film-state polymerization, an agitation polymer-
ization using a vertical agitation type polymerizer
vessel, and an agitation polymerization using a hori-
zontal agitation type polymerizer vessel.
The free-fall polymerization mentioned above is a
method in which at least one starting material, select-
ed from the group consisting of a molten monomer mix-
ture of an aromatic dihydroxy compound and a diaryl
carbonate and a molten prepolymer obtained by reacting
an aromatic dihydroxy compound with a diaryl carbonate,
is introduced to an introduction zone having a perfo-
rated plate and allowed to pass downwardly through the ;
perforated plate and fall freely through a free-fall
polymerization reaction zone, thereby effecting the
polymerization during the free-fall.
The term "free-fall" used in the present invention
means a fall under vacuum or non-vacuum conditions,
during which a falling starting material does not
contact an object causing resistance to fall, such as a
guide or a wall. The starting material is allowed to
fall freely in the form of a film, a filament, a drop-
let, a spray or the like. During the free-fall, by-
products, such as phenol, are evaporated from the
2168630
.
falling starting material being polymerized.
There is no particular limitation with respect to
the shape of holes of the perforated plate to be used
for conducting a free-fall polymerization in the
present invention. Generally, the morphology of a hole
is selected from a circle, an ellipse, a triangle, a
slit, a polygon, a star and the like. The area of each
hole of the perforated plate is usually from 0.01 to
100 cm2, preferably from 0.05 to 10 cm2, more prefera-
bly from 0.1 to 5 cm2. The perforated plate may have a
nozzle or the like connected thereto, as long as a
starting material can fall freely after passing such a
nozzle or the like. The distance between adjacent
holes is generally from 1 to 500 mm, preferably from 10
to 100 mm, more preferably from 15 to 50 mm, as meas-
ured between the centers of the adjacent holes. With
respect to the number of holes in the perforated plate,
- there is no particular limitation, but the number of
holes may vary depending on conditions, such as the
reaction temperature and pressure, the amount of cata-
lyst, and the range of molecular weight of a prepolymer
to be produced.
A distance through which the free-fall of the
starting material is conducted is preferably from 0.3
to 50 m, more preferably from 0.5 to 20 m, from the
66
2168630
perforated plate.
A flow rate at which the starting material passes
through the holes of the perforated plate may vary
depending on the molecular weight of the starting
material. The flow rate per hole is generally from
10-4 to 104 liters/hr, preferably from 10-2 to
102 liters/hr, more preferably from 0.1 to 50 liters/
hr.
The free-fall time is not particularly limited,
but is generally from 0.01 seconds to 1 hour.
A prepolymer obtained by the free-fall polymeriza-
tion can be withdrawn, as such, from the polymerizer,
but it is preferred that the prepolymer be recirculated
to the introduction zone having the perforated plate
for further free-fall polymerization. In this case,
residence time of prepolymer in a reservoir portion at
the bottom of the free-fall polymerization reaction
zone or in a recirculation line can be prolonged ac-
cording to the time necessary for polycondensation
reaction.
As the agitation vessel of the agitation type
polymerizer vessel, any of the agitation vessels de-
scribed, for example, in Chapter 11 of "Kagaku Sohchi
Binran ( Handbook o f Chemi cal Appara tus ) " edited by
"Kagaku Kogyo Kyokai (the Society of Chemical Engi-
67
2I68630
.
neers, Japan)", (1989) can be used. The morphology of
the agitation vessel is not particularly limited.
Generally, a vertical or a horizontal cylinder type
vessel can be used. The shape of the agitator is also
not particularly limited. Agitators of anchor type,
turbine type, screw type, ribbon type, double blade
type and the like can be used.
Examples of thin film-state polymerizers include a
wall-wetting fall polymerizer and polymerizers contain-
ing a centrifugal thin film heat exchanger or an agi-
tated thin film heat exchanger.
In a wall-wetting fall polymerization, a starting
material is fed in molten state to an upper portion of
a wall extending downwardly through a wall-wetting fall
polymerization reaction zone, and allowed to fall along
and in contact with the surface of the wall, thereby
effecting the polymerization during the wall-wetting
fall thereof. Examples of apparatuses which~can be
used for the wall-wetting fall polymerization includes
a reactor described, for example, in page 461 of Chap-
ter 11 of ~Kagaku Sohchi Binran (Handbook of Chemical
Apparatus)" (1989) edited by "Kagaku Kogyo Kyokai (the
Society of Chemical Engineers, Japan)". A wall-wetting
fall polymerizer may be of multiple tube type. Fur-
ther, a fallen prepolymer obtained at the bottom of the
68
2168630
wall-wetting fall polymerization reaction zone may be
recirculated to the top of the wall for further poly-
merization of the prepolymer.
Examples of agitated thin film heat exchangers and
centrifugal thin film heat exchangers include those
described in Chapters 21 and 22 of "Netsukoukanki
Sekkei Handbukku (Handbook for Designing Heat Exchang-
ers)" (1974) published by Kogak Tosho Co., Japan.
Examples of horizontal agitation type polymerizers
include those of screw type and separate blade typa.
Examples of screw type polymerizers include those of
single-screw type and twin-screw type. These horizon-
tal agitation type polymerizers are described, for
example, in the research report "Reactive Processing
Part 2" (1992) edited by Hannou Kougaku Kenkyukai
(Research Group of Reaction Engineering) of Koubunshi
Gakukai (Society of Polymer Science, Japan).
Preferred embodiments of combinations of the
process of the present invention with another polymeri-
zation method or other methods are explained below, but
these embodiments should not be construed as limiting
the scope of the present invention.
(1) Combination of a free-fall polymerization usinq a
perforated plate and a wire-wettinq fall polymerization
usinq a foraminous plate and a wire
69
2168630
-
One preferred example of modes of combinations of
the wire-wetting fall polymerization process with other
polymerization methods is a combination of a free-fall
polymerization using a perforated plate and a wire-
wetting fall polymerization using a foraminous plate
and a wire.
Fig. 3 shows an embodiment of this combination.
In Fig. 3, at least one starting material selected from
the group consisting of a molten monomer mixture of an
aromatic dihydroxy compound and a diaryl carbonatej and
a first prepolymer (defined above), is fed through
inlet 201 to recirculation line 202 of free-fall poly-
merizer 210 and then introduced to an introduction zone
having perforated plate 203, and is allowed to pass
through perforated plate 203 and fall freely through
the free-fall polymerization zone in free-fall polymer-
izer 210. Starting material 204 falls freely in the
form of a film, a filament, a droplet or a spray, while
being polymerized to form a prepolymer. The internal
pressure of the polymerizer 210 is controlled to a
predetermined value. A by-produced aromatic monohy-
droxy compound and the like evaporated from the poly-
merization system, and an inert gas, such as nitrogen,
which is optionally fed from gas feed port 205, are
discharged through vent 206. The resultant molten
2168630
prepolymer (and the unpolymerized molten monomer mix-
ture, if any) obtained at the bottom of the free-fall
polymerization zone is recirculated through recircula-
tion line 202 having recirculation pump 207 to the
introduction zone having perforated plate 203, and
allowed to pass through perforated plate 203.
After the degree of polymerization has reached a
predetermined level, prepolymer 211 (second prepolymer)
is withdrawn through outlet 209 and fed through inlet
lOlA of first wire-wetting fall polymerizer llOA to
recirculation line 102A by means of transfer pump 208.
The prepolymer is then fed to a feeding zone having
foraminous plate 103A and allowed to pass downwardly
through foraminous plate 103A and fall along and in
contact with wire 104A through the wire-wetting fall
polymerization zone of first wire-wetting fall polymer-
izer llOA. The internal pressure of the polymerizer
llOA is controlled to a predetermined level. A by-
produced aromatic monohydroxy compound and the like
evaporated from the prepolymer, and an inert gas, such
gas nitrogen, which is optionally fed from gas feed
port 105A, are discharged through vent 106A. The
resultant prepolymer obtained at the bottom of the
wire-wetting fall polymerization zone is recirculated
through recirculation line 102A having recirculation
2168630
-
pump 107A to the feeding zone having foraminous plate
103A and allowed to pass downwardly through foraminous
plate 103A.
After the degree of polymerization has reached a
predetermined level, prepolymer lllA is withdrawn
through outlet 109A and fed through inlet lOlB of
second wire-wetting fall polymerizer llOB to recircula-
tion line 102B by means of transfer pump 108A. The
prepolymer is then fed to the feeding zone having
foraminate plate 103B and allowed to pass downwardly
through foraminate plate 103B and fall along and in
contact with wire 104B though the wire-wetting fall
polymerization zone of second wire-wetting polymerizer
llOB .
The internal pressure of the polymerizer llOB is
controlled to a predetermined level. A by-produced
aromatic monohydroxy compound and the like evaporated
from the prepolymer, and an inert gas, such as nitro-
gen, which is optionally fed from gas feed port 105B,
are discharged through vent 106B. The resultant pre-
polymer obtained at the bottom of the wire-wetting fall
polymerization zone is recirculated through recircula-
tion line 102B having recirculation pump 107B to the
feeding zone having foraminous plate 103B and allowed
to pass downwardly through foraminous plate 103B.
21686~0
Resultant molten polymer lllB, obtained at the bottom
of the wire-wetting fall polymerization zone, is with-
drawn through outlet 109B by means of discharge pump
108B. With respect to both the free-fall and the
wire-wetting fall polymerizations, all of the polymer-
izers, recirculation lines, transfer lines, discharge
lines and the like are heated to and kept at an elevat-
ed temperature by means of a heater and a jacket.
(2) Combination of an aqitation polymerization usinq a
vertical aqitation type polymerizer vessel and a wire-
wettinq fall polymerization usinq a foraminous plate
and a wire
Another preferred example of modes of combinations
of the wire-wetting fall polymerization process with
other polymerization methods is a combination of an
agitation polymerization using a vertical agitation
type polymerizer vessel and a wire-wetting fall poly-
merization using a foraminous plate and a wire.
Fig. 4 shows an embodiment of this combination.
In Fig. 4, at least one starting material selected from
the group consisting of a monomer mixture of an aromat-
ic dihydroxy compound and a diaryl carbonate, and a
first prepolymer (defined above), is introduced to
first vertical agitation type polymerizer vessels 303A
and 303B, respectively, through inlet 301A of polymer-
2168630
izer 303A and inlet 301B of polymerizer 303B. First
agitation type polymerizer vessels 303A and 303B have
vertical agitators 306A and 306B, respectively. First
agitation type polymerizer vessels 303A and 303B are
the same, and are adapted to be alternately operated
when, for example, it is intended to produce a prepoly-
mer in a batchwise manner by means of each of these
polymerizer vessels 303A and 303B. Each of polymerizer
vessels 303A and 303Bis filled with an inert gas, such
as nitrogen, and the internal pressure of each polymer-
izer is usually controlled to a level around atmospher-
ic pressure. A by-produced and evaporated aromatic
monohydroxy compound and the like are discharged from
polymerizer vessels 303A and 303B, respectively,
through vents 302A and 302B. Prepolymers 304A and
304B, obtained by the polymerization for a predeter-
mined reaction time under agitation in respective
polymerizer vessels 303A and 303B, are discharged
through outlets 305A and 305B, respectively, trans-
ferred by means of transfer pump 309, and introduced to
second vertical agitation type polymerizer vessel 303C
through inlet 30lC.
Second agitation type polymerizer vessel 303C has
vertical agitator 306C. The interior of polymerizer
303Cis maintained at reduced pressure, and a by-pro-
2168630
.
duced and evaporated aromatic monohydroxy compound and
the like are discharged through vent 302C. Second
prepolymer (defined above) 304C, obtained by the poly-
merization for a predetermined reaction time under
agitation in polymerizer 303C, is discharged through
outlet 305C and transferred by means of transfer pump
307C to first wire-wetting fall polymerizer llOA,
having a foraminous plate.
That is, in the first wire-wetting fall polymeri-
zation, second prepolymer 304C, obtained by agitation
polymerization in second agitation type polymerizer
vessel 303C, is continuously fed to first wire-wetting
fall polymerizer llOA at its feeding zone (having
foraminous plate 103A) through inlet lOlA provided in
recirculation line 102A, and allowed to pass downwardly
through foraminous plate 103A and fall along and in
contact with wire 104A through a wire-wetting fall
polymerization reaction zone in first wire-wetting fall
polymerizer llOA. The internal pressure of the poly-
merizer is maintained at a predetermined level. A by-
produced and evaporated aromatic monohydroxy compound
and the like, and an inert gas, such as nitrogen, which
is optionally fed through gas feed port 105A, are
discharged through vent 106A. The resultant prepolymer
obtained at the bottom of the wire-wetting fall poly-
2168630
merization reaction zone is recirculated through recir-
culation line 102A (having recirculation pump 107A) to
the feeding zone having foraminous plate 103A, and
allowed to pass downwardly through foraminous plate
103A and fall along and in contact with wire 104A
through the wire-wetting fall polymerization reaction
zone in the wire-wetting fall polymerizer, thereby
increasing the degree of polymerization of the recircu-
lated prepolymer during the wire-wetting fall thereof.
Prepolymer lllA having a predetermined degree of poly-
merization is continuously withdrawn through outlet
lO9A, by means of transfer pump 108A, and fed to a
second wire-wetting fall polymerizer llOB at its feed-
ing zone (having foraminous plate 103B) through inlet -~
lOlB, and allowed to pass downwardly through foraminous
plate 103B and fall along and in contact with wire 104B
through a wire-wetting fall polymerization reaction
- zone in second wire-wetting fall polymerizer~llOB. The
internal pressure of the polymerizer is maintained at a
predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed
through gas feed port 105B, are discharged through vent
106B. Resultant molten polymer lllB, obtained at the
bottom of the wire-wetting fall polymerization reaction
- 2168630
zone, is withdrawn through outlet lOgB by means of
discharge pump 108B. With respect to both the agita-
tion and the wire-wetting fall polymerizations, all of
the polymerizers, recirculation lines, transfer lines,
discharge lines and the like are heated to and kept at
an elevated temperature by means of a heater and a
jacket.
(3) Combination of an aqitation polymerization usinq a
horizontal aqitation type polymerizer vessel and a
wire-wettinq fall polymerization usinq a foraminous
plate and a wire
Still another preferred example of modes of combi-
nations of the wire-wetting fall polymerization process
with other polymerization methods is a combination of
an agitation polymerization using a horizontal agita-
tion type polymerizer vessel and a wire-wetting fall
polymerization using a foraminous plate and a wire.
Fig. 5 shows an embodiment of this combination.
In Fig. 5, at least one starting material selected from
the group consisting of a monomer mixture of an aromat-
ic dihydroxy compound and a diaryl carbonate, and a
first prepolymer (defined above), is introduced to
horizontal agitation type polymerizer vessel 401
through inlet 402 of polymerizer 401. Agitation type
polymerizer vessel 401 has horizontal agitator 406.
2168630
The internal pressure of the polymerizer is maintained
at a predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed,
are discharged from polymerizer vessel 401 through vent
403. A second prepolymer (defined above), obtained by
the polymerization for a predetermined reaction time
under agitation in polymerizer 401, is discharged
through outlet 404 and transferred by means of transfer
pump 405 to wire-wetting fall polymerizer 110, having a
foraminous plate.
That is, in the wire-wetting fall polymerization,
the second prepolymer, obtained by agitation polymeri-
zation in agitation type polymerizer vessel 401, is
continuously fed to wire-wetting fall polymerizer 110
at its feeding zone (having foraminous plate 103)
through inlet 101 provided in recirculation line 102,
and allowed to pass downwardly through foraminous plate
103 and fall along and in contact with wire 104 through
a wire-wetting fall polymerization reaction zone in
wire-wetting fall polymerizer 110. The internal pres-
sure of the polymerizer is maintained at a predeter-
mined level. A by-produced and evaporated aromatic
monohydroxy compound and the like, and an inert gas,
such as nitrogen, which is optionally fed through gas
78
2168630
feed port 105, are discharged through vent .106. The
resultant prepolymer obtained at the bottom of the
wire-wetting fall polymerization reaction zone is
recirculated through recirculation line 102 (having
recirculation pump 107) to the feeding zone having
foraminous plate 103, and allowed to pass downwardly
through foraminous plate 103 and fall along and in
contact with wire 104 through the wire-wetting fall
polymerization reaction zone in the wire-wetting fall
polymerizer, thereby increasing the degree of polymeri-
zation of the recirculated prepolymer during the wire-
wetting fall thereof. Resultant molten polymer 111,
obtained at the bottom of the wire-wetting fall poly-
merization reaction zone, is withdrawn through outlet
109 by means of discharge pump 108. With respect to
both the agitation and the wire-wetting fall polymeri-
zations, all of the polymerizers, recirculation lines,
transfer lines, discharge lines and the like~are heated
to and kept at an elevated temperature by means of a
heater and a jacket.
(4) Combination of a thin film-state polymerization
and a wire-wettinq fall polymerization usinq a forami-
nous plate and a wire
A further preferred example of modes of combina-
tions of the wire-wetting fall polymerization process
79
2168630
with other polymerization methods is a combination of a
thin film-state polymerization and the wire-wetting
fall polymerization.
This combination is explained below by taking an
embodiment (shown in Fig. 6) in which a wall-wetting
fall polymerization is used as an example of a thin
film-state polymerization. In the wall-wetting fall
polymerization of this embodiment, a starting material
(defined above) is fed in molten state to an upper
portion of a wall extending through a wall-wetting fall
polymerization reaction zone, and the starting material
is allowed to fall along and in contact with the sur-
face of the wall, thereby effecting a wall-wetting fall
polymerization of the starting material during the
wall-wetting fall thereof to obtain a second prepolymer
at the bottom of the wall-wetting fall polymerization
reaction zone. Since a large heat-transfer surface
area is available in the wall-wetting fall polymeriza-
tion, it can efficiently provide latent heat of evapo-
r~tion of an aromatic monohydroxy compound and thelike. Further, because a large evaporating surface
area is available in the wall-wetting fall polymeriza-
tion, an aromatic monohydroxy compound and the like can
be removed efficiently, so that the polymerization can
proceed rapidly.
2168630
Fig. 6 shows an embodiment of the above-mentioned
combination. In Fig. 6, at least one starting material
selected from the group consisting of a monomer mixture
of an aromatic dihydroxy compound and a diaryl carbon-
ate, and a first prepolymer (defined above), is contin-
uously fed through inlet 501 and recirculation line 502
and introduced through overflow port 503 into wall-
wetting fall polymerizer 504. The introduced starting
material falls along and in contact with the inner wall
of a tube in the form of film-like prepolymer 505,
thereby effecting a wall-wetting fall polymerization.
The internal pressure of the polymerizer is maintained
at a predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed
through gas-feed port 506, are discharged through vent
507. The resultant prepolymer at the bottom of the
polymerizer is recirculated by means of recirculation
pump 508 to overflow port 503 of the wall-wetting
polymerizer through recirculation line 502 and intro-
duced to the wall-wetting fall polymerizer. Second
prepolymer 509, having a predetermined degree of poly-
merization, is withdrawn through outlet 511 and trans-
ferred by means of transfer pump 510 to first wire-
wetting fall polymerizer llOA (having a foraminous
81
2168630
plate). .
That is, in the first wire-wetting fall polymeri-
zation, second prepolymer 509, obtained by the wall-
wetting fall polymerization in wall-wetting fall poly-
merizer 504, is continuously fed to first wire-wetting
fall polymerizer llOA at its feeding zone (having
foraminous plate 10 3A ) through inlet 10 lA provided in
recirculation line 102A, and allowed to pass downwardly
through foraminous plate 10 3A and fall along and in ,
contact with wire 104A through a wire-wetting fall '
polymerization reaction zone in first wire-wetting fall
polymerizer llOA. The internal pressure of the poly-
merizer is maintained at a predetermined level. A by-
produced and evaporated aromatic monohydroxy compound
and the like, and an inert gas, such as nitrogen, which
is optionally fed through gas feed port 105A, are
discharged through vent 106A. The resultant prepolymer
obtained at the bottom of the wire-wetting fall poly-
merization reaction zone is recirculated through recir-
c,ulation line 102A (having recirculation pump 107A) to
the feeding zone having foraminous plate 103A, and
allowed to pass downwardly through foraminous plate
103A and fall along and in contact with wire 104A
through the wire-wetting fall polymerization reaction
zone in the wire-wetting fall polymerizer, thereby
82
2168630
.
increasing the degree of polymerization of .the recircu-
lated prepolymer during the wire-wetting fall thereof.
Prepolymer lllA having a predetermined degree of poly-
merization is withdrawn through outlet lO9A, by means
S of transfer pump 108A, and continuously fed to second
wire-wetting fall polymerizer llOB at its feeding zone
(having foraminous plate 103B) through inlet lOlB
provided in recirculation line 10 2B, and allowed to
pass downwardly through foraminous plate 103B and fall
along and in contact with wire 104B through a wire-
wetting fall polymerization reaction zone in second
wire-wetting fall polymerizer llOB. The internal
pressure of the polymerizer is maintained at a prede-
termined level. A by-produced and evaporated aromatic
monohydroxy compound and the like, and an inert gas,
such as nitrogen, which is optionally fed through gas
feed port 105B, are discharged through vent 106B. The
resultant prepolymer obtained at the bottom of the
wire-wetting fall polymerization reaction zone is
recirculated through recirculation line 102B ( having
recirculation pump 107B) to the feeding zone having
foraminous plate 103B, and allowed to pass downwardly
through foraminous plate 103B and fall along and in
contact with wire 104B through the wire-wetting fall
polymerization reaction zone in the wire-wetting fall
2168630
polymerizer, thereby increasing the degree.of polymeri-
zation of the recirculated prepolymer during the wire-
wetting fall thereof. Resultant molten polymer lllB,
obtained at the bottom of the wire-wetting fall poly-
S merization reaction zone, is withdrawn through outlet
lO9B by means of discharge pump 108B. With respect to
both the wall-wetting fall and the wire-wetting fall
polymerizations, all of the polymerizers, recirculation
lines, transfer lines, discharge lines and the like a,re
heated to and kept at an elevated temperature by means
of a heater and a jacket.
(5) Combination of an aq,itation polymerization usinq a
vertical aqitation type polymerizer vessel, a free-fall
polymerization usinq a perforated plate and a wire-
wettinq fall polymerization usinq a foraminous plate
and a wire
Still a further preferred example of modes of
combinations of the wire-wetting fall polymerization
process with other polymerization methods is a combina-
tion of an agitation polymerization using a vertical
agitation type polymerizer vessel, a free-fall polymer-
ization using a perforated plate and a wire-wetting
fall polymerization using a foraminous plate and a
wire.
Fig. 7 shows an embodiment of this combination.
84
2168630
In Fig. 7, at least one starting material s-elected from
the group consisting of a monomer mixture of an aromat-
ic dihydroxy compound and a diaryl carbonate, and a
first prepolymer (defined above), is introduced to
first vertical agitation type polymerizer vessels 303A
and 303B, respectively, through inlet 301A of polymer-
izer 303A and inlet 301B of polymerizer 303B. First
agitation type polymerizer vessels 303A and 303B have
vertical agitators 306A and 306B, respectively. First
agitation type polymerizer vessels 303A and 303B are
the same, and are adapted to be alternately operated
when, for example, it is intended to produce a prepoly-
mer in a batchwise manner by means of each of these
polymerizer vessels 303A and 303B. Each of polymerizer
vessels 303A and 303B is filled with an inert gas, such
as nitrogen, and the internal pressure of each polymer-
izer is usually controlled to a level around atmospher-
ic pressure. A by-produced and evaporated aromatic
monohydroxy compound and the like are discharged from
pG~lymerizer vessels 303A and 303B, respectively,
through vents 302A and 302B. Prepolymers 304A and
304B, obtained by the polymerization for a predeter-
mined reaction time under agitation in respective
polymerizer vessels 303A and 303B, are discharged
through outlets 305A and 305B, respectively, trans-
, 2168630
ferred by means of transfer pump 309, and introduced to
second vertical agitation type polymerizer vessel 303C
through inlet 30lC.
Second agitation type polymerizer vessel 303C has
vertical agitator 306C. The interior of polymerizer
303C is maintained at reduced pressure, and a by-pro-
duced and evaporated aromatic monohydroxy compound and
the like are discharged through vent 302C. Second
prepolymer (defined above) 304C, obtained by the poly-
merization for a predetermined reaction time under ~agitation in polymerizer 303C, is discharged through
outlet 305C and transferred by means of transfer pump
307C to free-fall polymerizer 210A, having a perforated
plate.
That is, in the free-fall polymerization, second
prepolymer 304C, obtained by the agitation polymeriza-
tion in polymerizer 303C, is continuously fed to free-
fall pol~rmerizer 210 at its introduction zone (having
perforated plate 203) through inlet 201 provided in
recirculation line 202, and allowed to pass through
perforated plate 203 and fall freely through a free-
fall polymerization reaction zone in free-fall polymer-
izer 210. Second prepolymer 204 falls freely in the
form of a film, a filament, a droplet or a spray. The
internal pressure of the polymerizer is maintained at a
86
21686~0
predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed
through gas feed port 205, are discharged through vent
206. The resultant prepolymer obtained at the bottom
of the free-fall polymerization reaction zone is recir-
culated through recirculation line 202 (having recircu-
lation pump 207) to the introduction zone having perfo-
rated plate 203, and allowed to pass through perfora~ed
plate 203 and fall freely through the free-fall pol-y-
merization reaction zone in the free-fall polymerizer,
thereby increasing the degree of polymerization of the
recirculated prepolymer during the free-fall thereof.
Resultant third prepolymer (defined above) 211 having a
predetermined degree of polymerization is continuously
withdrawn through outlet 209, by means of transfer pump
208, and fed to wire-wetting fall polymerizer 110
having foraminous plate 103.
That is, in the wire-wetting fall polymerization,
third prepolymer 211, obtained by free-fall polymeriza-
tion in free-fall polymerizer 210, is continuously fed
to wire-wetting fall polymerizer 110 at its feeding
zone (having foraminous plate 103) through inlet 101,
and allowed to pass downwardly through foraminous plate
103 and fall along and in contact with wire 104 through
87
2168630
a wire-wetting fall polymerization reaction.zone in
wire-wetting fall polymerizer 110. The internal pres-
sure of the polymerizer is maintained at a predeter-
mined level. A by-produced and evaporated aromatic
monohydroxy compound and the like, and an inert gas,
such as nitrogen, which is optionally fed through gas
feed port 105, are discharged through vent 106. Re-
sultant molten polymer 111, obtained at the bottom of
the wire-wetting fall polymerization reaction zone, is
withdrawn through outlet 109 by means of discharge pump
108. With respect to all of the agitation, the free-
fall and the wire-wetting fall polymerizations, all of
the polymerizers, recirculation lines, transfer lines,
discharge lines and the like are heated to and kept at
an elevated temperature by means of a heater and a
jacket.
(6) Combination of an aqitation polYmerization usinq a
vertical aqitation type polymerizer vessel, an aqita-
tion polymerization usinq a horizontal aqitation type
polymerizer vessel and a wire-wettinq fall polymeriza-
tion usinq a foraminous plate and a wire
Still a further preferred example of modes of
combinations of the wire-wetting fall polymerization
process with other polymerization methods is a combina-
tion of an agitation polymerization using a vertical
88
2168630
agitation type polymerizer vessel, an agitation poly-
merization using a horizontal agitation type polymeriz-
er vessel and a wire-wetting fall polymerization using
a foraminous plate and a wire.
Fig. 8 shows an embodiment of this combination.
In Fig. 8, at least one starting material selected from
the group consisting of a monomer mixture of an aromat-
ic dihydroxy compound and a diaryl carbonate, and a
first prepolymer (defined above), is introduced to
first vertical agitation type polymerizer vessels 303A
and 303B, respectively, through inlet 301A of polymer-
izer 303A and inlet 301B of polymerizer 303B. First
agitation type polymerizer vessels 303A and 303B have
vertical agitators 306A and 306B, respectively. First
agitation type polymerizer vessels 303A and 303B are
the same, and are adapted to be alternately operated
when, for example, it is intended to produce a prepoly-
mer in a batchwise manner by means of each of these
polymerizer vessels 303A and 303B. Each of polymerizer
vessels 303A and 303B is filled with an inert gas, such
as nitrogen, and the internal pressure of each polymer-
izer is usually controlled to a level around atmospher-
ic pressure. A by-produced and evaporated aromatic
monohydroxy compound and the like are discharged from
polymerizer vessels 303A and 303B, respectively,
89
2168630
.
through vents 302A and 302B. Prepolymers 304A and
304B, obtained by the polymerization for a predeter-
mined reaction time under agitation in respective
polymerizer vessels 303A and 303B, are discharged
through outlets 305A and 305B, respectively, trans-
ferred by means of transfer pump 309, and introduced to
second vertical agitation type polymerizer vessel 303C
through inlet 30lC.
Second agitation type polymerizer vessel 303C has
vertical agitator 306C. The interior of polymerizer
303C is maintained at reduced pressure, and a by-pro-
duced and evaporated aromatic monohydroxy compound and
the like are discharged through vent 302C. Second
prepolymer (defined above) 304C, obtained by the poly-
merization for a predetermined reaction time under
agitation in polymerizer 303C, is discharged through
outlet 305C and transferred by means of transfer pump
307C to horizontal agitation type polymerizer vessel
401 through inlet 402 of polymerizer 401.
Agitation type polymerizer vessel 401 has horizon-
tal agitator 406. The internal pressure of the poly-
merizer is maintained at a predetermined level. A by-
produced and evaporated aromatic monohydroxy compound
and the like, and an inert gas, such as nitrogen, which
is optionally fed, are discharged from polymerizer
2168630
vessel 401 through vent 403. A third prepolymer
(defined above), obtained by the polymerization for a
predetermined reaction time under agitation in polymer-
izer 401, is discharged through outlet 404 and trans-
ferred by means of transfer pump 405 to wire-wetting
fall polymerizer 110, having a foraminous plate.
That is, in the wire-wetting fall polymerization,
the third prepolymer, obtained by agitation polymeriza-
tion in horizontal agitation type polymerizer vessel
401, is continuously fed to wire-wetting fall poly~er-
izer 110 at its feeding zone (having foraminous plate
103) through inlet 101, and allowed to pass downwardly
through foraminous plate 103 and fall along and in
contact with wire 104 through a wire-wetting fall
polymerization reaction zone in wire-wetting fall
polymerizer 110. The internal pressure of the polymer-
izer is maintained at a predetermined level. A by-
produced and evaporated aromatic monohydroxy compound
and the like, and an inert gas, such as nitrogen, which
is optionally fed through gas feed port 105, are dis-
charged through vent 106. Resultant molten polymer
111, obtained at the bottom of the wire-wetting fall
polymerization reaction zone, is withdrawn through
outlet 109 by means of discharge pump 108. With re-
spect to both the agitation and the wire-wetting fall
91
2168630
polymerizations, all of the polymerizers, transfer
lines, discharge lines and the like are heated to and
kept at an elevated temperature by means of a heater
and a jacket.
s (7) Combination of an aqitation polymerization usinq a
vertical aqitation type polymerizer vessel, a thin
film-state polymerization and a wire-wettinq fall
polymerization usinq a foraminous plate and a wire
Still a further preferred example of modes of
combinations of the wire-wetting fall polymerization
process with other polymerization methods is a combina-
tion of an agitation polymerization using a vertical
agitation type polymerizer vessel, a thin film-state
polymerization and the wire-wetting fall polymeriza-
tion.
This combination is explained below by taking an
embodiment (shown in Fig. 9) in which a wall-wetting
fall polymerization is used as an example of a thin
film-state polymerization.
Fig. 9 shows an embodiment of this combination.
In Fig. 9, at least one starting material selected from
the group consisting of a monomer mixture of an aromat-
ic dihydroxy compound and a diaryl carbonate, and a
first prepolymer (defined above), is introduced to
first vertical agitation type polymerizer vessels 303A
92
2168630
and 303B, respectively, through inlet 301Aof polymer-
izer 303A and inlet 301B of polymerizer 303B. First
agitation type polymerizer vessels 303A and 303B have
vertical agitators 306A and 306B, respectively. First
agitation type polymerizer vessels 303A and 303B are
the same, and are adapted to be alternately operated
when, for example, it is intended to produce a prepoly-
mer in a batchwise manner by means of each of these
polymerizer vessels 303A and 303B. Each of polymerizer
vessels 303A and 303Bis filled with an inert gas,-such
as nitrogen, and the internal pressure of each polymer-
izer is usually controlled to a level around atmospher-
ic pressure. A by-produced and evaporated aromatic
monohydroxy compound and the like are discharged from
polymerizer vessels 303A and 303B, respectively,
through vents 302A and 302B. Prepolymers 304A and
304B, obtained by the polymerization for a predeter-
mined reaction time under agitation in respective
polymerizer vessels 303A and 303B, are discharged
through outlets 305A and 305B, respectively, trans-
ferred by means of transfer pump 309, and introduced to
second vertical agitation type polymerizer vessel 303C
through inlet 30lC.
Second agitation type polymerizer vessel 303C has
vertical agitator 306C. The interior of polymerizer
93
2168630
303C is maintained at reduced pressure, and a by-pro-
duced and evaporated aromatic monohydroxy compound and
the like are discharged through vent 302C. Second
prepolymer (defined above) 304C, obtained by the poly-
merization for a predetermined reaction time under
agitation in polymerizer 303C, is discharged through
outlet 305C and transferred by means of transfer pump
307C to wall-wetting fall polymerizer 504.
That is, in the wall-wetting fall polymerization,
second prepolymer (defined above) 304C, obtained by-
agitation polymerization in polymerizer 303C, is con-
tinuously fed through inlet 501 and recirculation line
502 and introduced through overflow port 503 into
wall-wetting fall polymerizer 504. The introduced
second prepolymer falls along and in contact with the
inner wall of a tube in the form of film-like prepoly-
mer 505, thereby effecting a wall-wetting fall polymer-
ization. The internal pressure of the polymerizer is
maintained at a predetermined level. A by-produced and
evaporated aromatic monohydroxy compound and the like,
and an inert gas, such as nitrogen, which is optionally
fed through gas-feed port 506, are discharged through
vent 507. The resultant prepolymer at the bottom of
the polymerizer is recirculated by means of recircula-
tion pump 508 to overflow port 503 of the wall-wetting
94
2168S30
fall polymerizer through recirculation line- 502 and
introduced to the wall-wetting fall polymerizer. Third
prepolymer (defined above) 509, having a predetermined
degree of polymerization, is withdrawn through outlet
511 and transferred by means of transfer pump 510 to
first wire-wetting fall polymerizer llOA (having a
foraminous plate).
That is, in the first wire-wetting fall polymeri-
zation, third prepolymer 509, obtained by the wall-
wetting fall polymerization in wall-wetting fall poly-
merizer 504, iS continuously fed to first wire-wetting
fall polymerizer llOA at its feeding zone (having
foraminous plate 10 3A ) through inlet 10 lA provided in
recirculation line 102A, and allowed to pass downwardly
through foraminous plate 103A and fall along and in
contact with wire 104A through a wire-wetting fall
polymerization reaction zone in first wire-wetting fall
polymerizer llOA. The internal pressure of the poly-
merizer is maintained at a predetermined level. A by-
produced and evaporated aromatic monohydroxy compound
and the like, and an inert gas, such as nitrogen, which
is optionally fed through gas feed port 105A, are
discharged through vent 106A. The resultant prepolymer
obtained at the bottom of the wire-wetting fall poly-
merization reaction zone is recirculated through recir-
2168630
culation line 102A (having recirculation pump 107A) to
the feeding zone having foraminous plate 103A, and
allowed to pass downwardly through foraminous plate
103A and fall along and in contact with wire 104A
through the wire-wetting fall polymerization reaction
zone in the wire-wetting fall polymerizer, thereby
increasing the degree of polymerization of the recircu-
lated prepolymer during the wire-wetting fall thereof.
Prepolymer lllA having a predetermined degree of poly-
merization is continuously withdrawn through outletlO9A, by means of transfer pump 108A, and fed to second
wire-wetting fall polymerizer llOB at its feeding zone
(having foraminous plate 103B) through inlet lOlB, and
allowed to pass downwardly through foraminous plate
103B and fall along and in contact with wire 104B
through a wire-wetting fall polymerization reaction
zone in second wire-wetting fall polymerizer llOB. The
internal pressure of the polymerizer is maintained at a
predetermined level. A by-produced and evaporated
aromatic monohydroxy compound and the like, and an
inert gas, such as nitrogen, which is optionally fed
through gas feed port 105B, are discharged through vent
106B. Resultant moIten polymer lllB, obtained at the
bottom of the wire-wetting fall polymerization reaction
zone, is withdrawn through outlet lO9B by means of
96
2168630
discharge pump 108B. With respect to all of the agita-
tion, the wall-wetting fall and the wire-wetting fall
polymerizations, all of the polymerizers, recirculation
lines, transfer lines, discharge lines and the like are
heated to and kept at an elevated temperature by means
of a heater and a jacket.
With respect to materials for constructing the
polymerizers to be used in the method of the present
invention, there is no particular limitation, but
stainless steel, nickel or glass is generally used as a
material for at least inner wall portions of polymeriz-
ers.
In the present invention, it is also preferred
that the inner wall of a polymerizer be wetted with
part of a recirculated polymer in order to prevent
sticking of scales to the inner wall of the polymeriz-
er.
Hereinbelow is given a flow chart showing pre-
ferred embodiments of the method of the present inven-
tion.
97
2168~30
v
..
r~
uoF~szFla~ lod a~ s-~lF~ U
~1, k~ ~ ~o UoF~z~F~ aal~ ~
--\ ` \ ~
A \ ~
o , , ~.,
3~o~\ \
rrs ~ 5--
n5
O
c~ -1 n5~
O~J r~ UoF~ln~lF~a~ n5 r~
a5 V r~
JJ ~ > ~ 04~ ~
~ ~ UOI~BZF:lallL610d a5~ 0 ~\
I 11~ uF~a~-alF~q r n ~
n5
O I ~ ~ O
v
O _ 1
r~
r ~ uoF~,ezFIaT~Iod ~
a~e~S-t~lFJ. UF~
n 0~0UOI~eZl:~alIL610d ~ ~0
la~ UoF~2~F~ o ~uoF~,ezFIa~ lod O
~l l e~ - a a l,~ :~
I
98
2168630
-
As can be seen from the above flow chart, the
monomer mixture, the first prepolymer the second pre-
polymer or the third prepolymer can be polymerized by a
wire-wetting fall polymerization to obtain an aromatic
polycarbonate of a desired degree of polymerization,
and the obtained aromatic polycarbonate may be recircu-
lated to the feeding zone for wire-wetting fall poly-
merization in order to increase the degree of polymeri-
zation.
2168630
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinbelow, the present invention will be de-
scribed in more detail with reference to the following
Examples and Comparative Examples, but they should not
be construed as limiting the scope of the present
invention.
In the following Examples and Comparative Exam-
ples, the molecular weight is expressed in terms of the
number average molecular weight (hereinafter referred
to simply as "Mn") as measured by gel permeation
chromatography (GPC). The color of the aromatic poly-
carbonate produced was evaluated, using a specimen
having a thickness of 3.2 mm, in accordance with the
CIELAB method, and the yellowness of the specimen is .
expressed in terms of the b*-value.
Example 1
A wire-wetting fall polymerization reaction was
- carried out using a polymerization apparatus~as shown
in Fig. 2. Wire-wetting fall polymerizer 110 (con-
tained in the polymerization apparatus) is equipped
with foraminous plate 103, which has 50 holes each
having a diameter of 7.5 mm and arranged in a zigzag
configuration in which the distance (pitch) between the
adjacent holes is 30 mm as measured between the centers
of the adjacent holes. In wire-wetting fall polymeriz-
-- 100 --
2168630
er 110, 50 strands of 0.1 mm~ SUS 316 wires are hung
vertically from the respective holes of foraminous
plate 103 to a reservoir portion at the bottom of
wire-wetting fall polymerizer 110, wherein, as shown in
Fig. 10, each wire 104 is secured at the upper end
thereof to support rod 123 provided above foraminous
plate 103, and extends downwardly through hole 121 of
foraminous plate 103. The wire-wetting fall distance
is 4 m.
30 Liters of a prepolymer having an Mn of 4,700,
prepared by reacting bisphenol A with diphenyl carbon-
ate in a molar ratio of 1:1.05, were introduced to
wire-wetting fall polymerizer 110, and a wire-wetting
fall polymerization reaction was batchwise carried out
for 2 hours under polymerization reaction conditions
wherein the reaction temperature was 280 C, the reac-
tion pressure was 0.4 mmHg, and the flow rate of nitro-
gen gas was 2 liters/hr to obtain a polymer, while
recirculating the obtained polymer to the feeding zone
(having foraminous plate 103) of wire-wetting fall
polymerizer 110 through recirculation line 102 at a
recirculation rate of 25 liters/hr (i.e., a recircula-
tion rate with respect to each hole of foraminous plate
103 is 0.5 liter/hr). Resultant polymer 111, which was
withdrawn through outlet 109 by means of discharge pump
-- 101 --
2168630
108, was a colorless transparent aromatic polycarbonate
having an Mn of 5,500 and a b*-value of 3.3.
Example 2
A wire-wetting fall polymerization reaction was
carried out using a polymerization apparatus as shown
in Fig. 1. Wire-wetting fall polymerizer 110 (con-
tained in the polymerization apparatus) is equipped
with foraminous plate 103, which has 10 holes having a
diameter of 5 mm and arranged in a zigzag configura-
tion. In wire-wetting fall polymerizer 110, lO strands
of 0.8 mm~ SUS 316 wires are hung vertically from the
respective holes of foraminous plate 103 to a reservoir
portion at the bottom of wire-wetting fall polymerizer
llO, wherein, as shown in Fig. 10, each wire 104 is
secured at the upper end thereof to support rod 123
provided above foraminous plate 103, and extends down-
wardly through hole 121 of foraminous plate 103. The
wire-wetting fall distance is 4 m.
A prepolymer having an Mn of 7,800, prepared by
reacting bisphenol A with diphenyl carbonate in a molar
ratio of 1:1.08, was continuously fed to wire-wetting
fall polymerizer 110 at 5 liters/hr (i.e., 0.5 liter/hr
with respect to each hole of foraminous plate 103), so
that a wire-wetting fall polymerization reaction of the
prepolymer was carried out under polymerization reac-
- 102 -
2168630
tion conditions wherein the reaction temperature was
250 C, the reaction pressure was 0.3 mmHg, and the
flow rate of nitrogen gas was 1 liter/hr, while contin-
uously withdrawing a part of produced polymer 111 so
that the level of polymer 111 in the reservoir portion
at the bottom of wire-wetting fall polymerizer 110 was
constantly maintained. The wire-wetting fall polymeri-
zation was continuously conducted for 1,000 hours. The
average residence time of the prepolymer in wire-wet-
ting fall polymerizer 110 was 2 hours. Results are
shown in Table 1. After completion of the wire-wetting
fall polymerization reaction, no accumulation of low
molecular weight polymer and the like was observed on
foraminous plate 103.
Examples 3 to 5
Polymerization reactions of the same prepolymer as
used in Example 2 (which had been prepared by reacting
bisphenol A with diphenyl carbonate in a molar ratio of
1:1.08) were individually carried out using the same
polymerization apparatus as used in Example 2 and shown
in Fig. 1, in substantially the same manner as in
Example 2, except that the polymerization reaction
conditions were varied as shown in Table 1. Results
are shown in Table 1. After completion of the wire-
wetting fall polymerization reaction in any of Examples
- 103 -
2168630
3 to 5, no accumulation of low molecular weight polymer
and the like was observed on foraminous plate 103.
Comparative Example l
An aromatic polycarbonate was produced using a
horizontal twin-screw agitation type polymerizer in-
stead of a wire-wetting fall polymerizer. The horizon-
tal twin-screw agitation type polymerizer has a capaci-
ty of 30 liters, an L/D ratio of 6, and a twin-screw
agitator having a rotation diameter of 140 mm.
An agitation polymerization reaction was conti-nu-
ously carried out while continuously feeding the same
prepolymer as used in Example 2 at a flow rate of 5
liters/hr and continuously withdrawing a part of the
produced aromatic polycarbonate so that the volume of
the reaction mixture in the twin-screw agitation type
polymerizer was constantly maintained at 10 liters.
The reaction conditions of the agitation polymerization
reaction were as follows: the reaction was carried out
for 1,000 hours, the reaction temperature was 250 C,
and the reaction pressure was 0.3 mmHg. Samples were
taken from the produced aromatic polycarbonates which
were withdrawn at time points of 200 hours, 400 hours,
600 hours, 800 hours and 1,000 hours after the start of
the polymerization reaction. The samples of the pro-
duced aromatic polycarbonates withdrawn at time points
- 104 -
21686~0
of 200 hours, 400 hours, 600 hours, 800 hours and 1,000
hours after the start of the reaction had b*-values of
3.6, 3.7, 3.8, 3.8 and 3.9, respectively, and had Mn
values of 8,800, 9,000, 8,700, 8,500 and 8,600, respec-
tively.
Comparative Example 2
An aromatic polycarbonate was produced using an
agitation type polymerizer vessel instead of a wire-
wetting fall polymerizer. The agitation type polymer-
izer has a capacity of 30 liters. The agitating biades
of the agitation type polymerizer vessel are of anchor
type .
An agitation polymerization reaction was continu-
ously carried out while continuously feeding the same
prepolymer as used in Example 2 at a flow rate of 5
liters/hr and continuously withdrawing a part of the
produced aromatic polycarbonate so that the volume of
the reaction mixture in the agitation type polymerizer
was constantly maintained at 10 liters. The reaction
conditions of the agitation polymerization reaction
were as follows: the reaction was carried out for 1,000
hours, the reaction temperature was 250 C, and the
reaction pressure was 0.3 mmHg. Samples were taken
from the produced aromatic polycarbonates which were
withdrawn at time points of 200 hours, 400 hours, 600
- 105 -
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hours, 800 hours and 1,000 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours, 600 hours, 800 hours and 1,000 hours
after the start of the reaction had b*-values of 3.5,
3.6, 3.7, 3.8 and 3.8, respectively, and had Mn values
of 8,000, 8,100, 8,000, 8,100 and 8,000, respectively.
Example 6
The same polymerization apparatus as in Example 1
and shown in Fig. 2 was used. 30 Liters of a mixture,
which was prepared by adding 1 x 10-6 mol of sodium
hydroxide and 3 x 10-6 mol of tetramethyl ammonium
hydroxide to a molten mixture of bisphenol A and diphe-
nyl carbonate (molar ratio of 1:1.05) per mole of
bisphenol A, were introduced to wire-wetting fall
polymerizer 110, and a wire-wetting fall polymerization
reaction was batchwise carried out for 50 minutes under
polymerization reaction conditions wherein the reaction
temperature was 250 C, the reaction pressure was
90 mmHg, and the flow rate of nitrogen gas was 3 lit-
ers/hr to obtain a polymer, while recirculating the
obtained polymer to the feeding zone (having foraminous
plate 103) of wire-wetting fall polymerizer 110 through
recirculation line 102 at a recirculation rate of 800
liters/hr (i.e., a recirculation rate with respect to
- 106 -
~2168630
each hole of foraminous plate 103 is 16 liters/hr).
The reaction was further continued for 30 minutes under
a pressure of 12 mmHg. Resultant polymer 111, which
was withdrawn through outlet 109 by means of discharge
pump 108, was a colorless transparent aromatic polycar-
bonate having an Mn of 2,500 and a b -value of 3.1.
Example 7
The same polymerization apparatus as used in
Example 1 and shown in Fig. 2 was used. A wire-wetting
fall polymerization reaction was carried out in sub-
stantially the same manner as in Example 6, except that
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane
was used instead of bisphenol A. A colorless transpar-
ent aromatic polycarbonate having an Mn of 2,400 and a
b*-value of 3.1 was obtained.
Example 8
An aromatic polycarbonate was produced in accord-
- ance with a system shown in Fig. 3. The system of Fig.
3 comprises a free-fall polymerization, and first stage
and second stage wire-wetting fall polymerizations.
In the free-fall polymerization, free-fall poly-
merizer 210 was used. Free-fall polymerizer 210 is
equipped with a perforated plate which has 50 holes
having a diameter of 3 mm and arranged in a zigzag
configuration. The free-fall distance is 4 m.
- 107 -
~ 2168630
In the first stage wire-wetting fall polymeriza-
tion, first wire-wetting fall polymerizer llOA was
used. In the second stage wire-wetting fall polymeri-
zation, second wire-wetting fall polymerizer llOB was
used. Each of the first and second wire-wetting fall
polymerizers was equipped with a foraminous plate which
had 20 holes having a diameter of 5 mm and arranged in
a zigzag configuration. In each of the first and
second wire-wetting fall polymerizers, 20 strands of
Q.8 mm~ SUS 316 wires are hung vertically from the
respective holes of the foraminous plate to a reservoir
portion at the bottom of the wire-wetting fall polymer-
izer, wherein each wire is secured in the same manner
as described in Example 1 and shown in Fig. 10. In
each of the first and second wire-wetting fall polymer-
izers, the wire-wetting fall distance is 6 m.
A molten mixture of bisphenol A and diphenyl
carbonate (molar ratio of 1:1.05) was continuously fed
to free-fall polymerizer 210 at 2 liters/hr, so that a
free-fall polymerization reaction of the molten mixture
was carried out under polymerization reaction condi-
tions wherein the reaction temperature was 240 C, and
the reaction pressure was 30 mmHg, thereby obtaining
prepolymer 211, while recirculating obtained prepolymer
211 to the introduction zone (having perforated plate
- 108 -
21686~0
203) of free-fall polymerizer 210 through r-ecirculation
line 202 at a recirculation rate of 500 liters/hr.
When the volume of prepolymer 211 at the bottom of
free-fall polymerizer 210 reached 10 liters, part of
prepolymer 211 was continuously fed to first wire-
wetting fall polymerizer llOA so that the volume of
prepolymer 211 in free-fall polymerizer 210 was con-
stantly maintained at 10 liters. The feeding of pre-
polymer 211 to first wire-wetting fall polymerizer llOA
was conducted through inlet lOlA provided in recircula-
tion line 102A for wire-wetting fall polymerizer llOA.
In first wire-wetting fall polymerizer llOA, a
wire-wetting fall polymerization of prepolymer 211 was
continuously carried out under polymerization reaction
conditions wherein the reaction temperature was 250 C,
and the reaction pressure was 5.0 mmHg, thereby obtain-
ing prepolymer lllA, while recirculating a part of
obtained prepolymer lllA to the feeding zone (having
foraminous plate 103A) of first wire-wetting fall
polymerizer llOA through recirculation line 102A at a
recirculation rate of 100 liters/hr.
When the volume of prepolymer lllA at the bottom
of first wire-wetting fall polymerizer llOA reached 10
liters, part of prepolymer lllA was continuously fed to
second wire-wetting fall polymerizer llOB so that the
- 109 --
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volume of prepolymer lllA in first wire-wetting fall
polymerizer llOA was constantly maintained at 10 lit-
ers.
In second wire-wetting fall polymerizer llOB, a
wire-wetting fall polymerization reaction was continu-
ously carried out under polymerization reaction condi-
tions wherein the reaction temperature was 280 C, and
the reaction pressure was 1.0 mmHg, thereby obtaining
polymer lllB, while recirculating a part of obtained
polymer lllB to the feeding zone (having foraminous
plate 103B) of second wire-wetting fall polymerizer
llOB through recirculation line 102B at a recirculation
rate of 20 liters/hr.
When the volume of polymer lllB at the bottom of
second wire-wetting fall polymerizer llOB reached 10
liters, polymer lllB was continuously withdrawn from
second wire-wetting fall polymerizer llOB through
outlet lO9B by means of discharge pump 108B so that the
~ volume of polymer lllB in second wire-wetting fall
polymerizer llOB was constantly maintained at 10 lit-
ers.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
-- 110 --
2168630
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b*-values of 3.2, 3.2 and 3.2, respective-
ly, and had Mn values of 9,100, 9,000 and 9,100, re-
spectively. After completion of the series of polymer-
ization reactions continuously conducted for 600 hours,
no accumulation of low molecular weight polymer and the
like was observed on the perforated plate in the free-
fall polymerizer and the foraminous plate in each of
the first and second wire-wetting fall polymerizers.
Example 9
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 4. The system of
Fig. 4 comprises first stage and second stage agitation
polymerizations, and first stage and second stage
wire-wetting fall polymerizations.
In the first stage wire-wetting fall polymeriza-
tion, first wire-wetting fall polymerizer llOA was
used. In the second stage wire-wetting fall polymeri-
zation, second wire-wetting fall polymerizer llOB was
used. Each of the first and second wire-wetting fall
polymerizers is equipped with a foraminous plate which
has 20 holes having a diameter of 5 mm and arranged in
-- 111 --
2168530
a zigzag conflguration. In each of the first and
second wire-wetting fall polymerizers, 20 strands of
0.8 mm~ SUS 316 wires are hung vertically from the
respective holes of the foraminous plate to a reservoir
portion at the bottom of the wire-wetting fall polymer-
izer, wherein each wire is secured in the same manner
as described in Example 1 and shown in Fig. 10. In
each of the first and second wire-wetting fall polymer-
izers, the wire-wetting fall distance is 6 m. Only
first wire-wetting fall polymerizer 110A has a recircu-
lation line.
The first stage agitation polymerization in first
agitation type polymerizer vessels 303A and 303B was
batchwise conducted, whereas the second stage agitation
polymerization in second agitation type polymerizer
vessel 303C, and the first stage and second stage
wire-wetting fall polymerizations in first and second
wire-wetting fall polymerizers 110A and 110B, were
continuously conducted.
The polymerization reaction conditions in both of
first agitation type polymerizer vessels 303A and 303B
were as follows: the reaction temperature was 180 C,
the reaction pressure was atmospheric pressure, and the
flow rate of nitrogen gas was 1 liter/hr.
In operation, 80 kg of a monomer mixture of bis-
- 112 -
2168630
phenol A and diphenyl carbonate in a molar ratio of
1:1.10 was charged into each of first agitation type
polymerizer vessels 303A and 303B. The monomer mixture
in polymerizer 303A was polymerized in a molten state
while agitating for 4 hours to obtain prepolymer 304A.
Outlet 305A was opened, and prepolymer 304A was fed to
second agitation type polymerizer vessel 303C at a flow
rate of 5 liters/hr.
While feeding prepolymer 304A obtained in first
agitation type polymerizer vessel 303A to second agita-
tion type polymerizer vessel 303C, first agitation type
polymerizer vessel 303B was operated to polymerize the
monomer mixture of bisphenol A and diphenyl carbonate
in the same manner as in the agitation polymerization
in first agitation type polymerizer vessel 303A, to
obtain prepolymer 304B.
When first agitation type polymerizer vessel 303A
became empty, outlet 305A of polymerizer 303A was
closed and, instead, outlet 305B of polymerizer 303B
was opened, so that prepolymer 304B was fed from first
agitation type polymerizer vessel 303B to second agita-
tion type polymerizer vessel 303C at a flow rate of 5
liters/hr. In this instance, the same monomer mixture
of bisphenol A and diphenyl carbonate as mentioned
above was charged in polymerizer 303A. While feeding
-113-
2168630
prepolymer 304B obtained in first agitation type poly-
merizer vessel 303B to second agitation type polymeriz-
er vessel 303C, polymerizer vessel 303A was operated,
so that the monomer mixture charged therein was poly-
merized in the same manner as mentioned above.
With respect to the batchwise polymerization in
first agitation type polymerizer vessels 303A and 303B
and to the alternate feedings of prepolymers 304A and
304B from polymerizers 303A and 303B to second agita-
tion type polymerizer vessel 303C, the same operation
as mentioned above was repeated, so that the prepolymer
(either prepolymer 304A or prepolymer 304B, alternate-
ly) was continuously fed to second agitation type
polymerizer vessel 303C.
In second agitation type polymerizer vessel 303C,
a further agitation polymerization of prepolymers 304A
and 304B, alternately fed from first agitation type
polymerizer vessels 303A and 303B, was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 240 C, the reac-
tion pressure was 70 mmHg and the flow rate of nitrogen
gas was 2 liters/hr, thereby obtaining prepolymer 304C.
When the volume of prepolymer 304C in second
agitation type polymerizer vessel 303C reached 20
liters, part of prepolymer 304C was continuously fed to
- 114 -
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first wire-wetting fall polymerizer llOA so that the
volume of prepolymer 304C in second agitation type
polymerizer vessel 303C was constantly maintained at 20
liters. The feeding of prepolymer 304C to first wire-
wetting fall polymerizer llOA was conducted through
inlet lOlA provided in recirculation line 102A for
polymerizer 11 OA .
In first wire-wetting fall polymerizer llOA, a
wire-wetting fall polymerization of prepolymer 304C was
continuously carried out under polymerization reaction
conditions wherein the reaction temperature was 260 C,
and the reaction pressure was 4.0 mmHg, thereby obtain-
ing prepolymer lllA, while recirculating a part of
obtained prepolymer lllA to the feeding zone (having
foraminous plate 103A) of first wire-wetting fall
polymerizer llOA through recirculation line 102A at a
recirculation rate of 80 liters/hr.
When the volume of prepolymer lllA at the bottom
of first wire-wetting fall polymerizer llOA reached 10
liters, part of prepolymer lllA was continuously fed to
second wire-wetting fall polymerizer llOB so that the
volume of prepolymer lllA in first wire-wetting fall
polymerizer llOA was constantly maintained at 10 lit-
ers.
In second wire-wetting fall polymerizer llOB, a
- 115 -
z 1 ~ ~ b ~ U
wire-wetting fall polymerization reaction was continu-
ously carried out under polymerization reaction condi-
tions wherein the reaction temperature was 270 C, and
the reaction pressure was 0.5 mmHg, thereby obtaining
polymer lllB.
When the volume of polymer lllB at the bottom of
second wire-wetting fall polymerizer llOB reached 10
liters, polymer lllB was continuously withdrawn from
second wire-wetting fall polymerizer llOB through
outlet lO9B by means of discharge pump 108b so that the
volume of polymer lllB in second wire-wetting fall
polymerizer llOB was constantly maintained at 10 lit-
ers.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b*-values of 3.3, 3.2 and 3.2, respective-
ly, and had Mn values of 8,200, 8,200 and 8,200, re-
spectively. After completion of the series of polymer-
ization reactions continuously conducted for 600 hours,
- 116 -
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no accumulation of low molecular weight polymer and the
like was observed on the perforated plate in each of
the first and second free-fall polymerizers, and the
foraminous plate in each of the first and second wall-
wetting fall polymerizers.
Example 10
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 5. The system of
Fig. 5 comprises an agitation polymerization, and a
wire-wetting fall polymerization.
In the agitation polymerization, horizontal twin-
screw agitation type polymerizer 401 was used. Hori-
zontal twin-screw agitation type polymerizer 401 has a
capacity of 30 liters, an L/D ratio of 6, and a twin-
screw agitator having a rotation diameter of 140 mm.
In the wire-wetting fall polymerization, wire-
wetting fall polymerizer 110 was used. First wire-
wetting fall polymerizer 110 is equipped with a forami-
nous plate which has 20 holes having a diameter of 4 mm
and arranged in a zigzag configuration. In wire-wet-
ting fall polymerizer 110, 20 strands of 1.0 mm~ SUS
316 wires are hung vertically from the respective holes
of foraminous plate 103 to a reservoir portion at the
bottom of wire-wetting fall polymerizer 110, wherein
each wire is secured in the same manner as described in
- 117 -
2168630
-
Example 1 and shown in Fig. 10. In wire-wetting fall
polymerizer 110, the wire-wetting fall distance is 4 m.
A molten mixture of bisphenol A and diphenyl
carbonate (molar ratio of 1:1.07) was continuously fed
to horizontal twin-screw agitation type polymerizer 401
at 5 liters/hr, so that an agitation polymerization
reaction of the molten mixture was carried out under
polymerization reaction conditions wherein the reaction
temperature was 230 C, and the reaction pressure was
~ 50 mmHg, thereby obtaining a prepolymer.
When the volume of the prepolymer in horizontal
twin-screw agitation type polymerizer 401 reached 15
liters, part of the prepolymer was continuously fed to
wire-wetting fall polymerizer 110 so that the volume of
the prepolymer in pol~merizer 401 was constantly main-
tained at 15 liters. The feeding of the prepolymer to
wire-wetting fall polymerizer 110 was conducted through
~ inlet 101 provided in recirculation line 102 for wire-
wetting fall polymerizer 110.
In wire-wetting fall polymerizer 110, a wire-
wetting fall polymerization of the prepolymer obtained
in horizontal twin-screw agitation type polymerizer 401
was continuously carried out under polymerization
reaction conditions wherein the reaction temperature
was 260 C, and the reaction pressure was 2.0 mmHg,
- - 118 -
2168630
thereby obtaining polymer 111, while recirculating a
part of obtained polymer 111 to the feeding zone
(having foraminous plate 103) of wire-wetting fall
polymerizer 110 through recirculation line 102 at a
recirculation rate of 80 liters/hr.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b*-values of 3.3, 3.3 and 3.4, respective-
ly, and had Mn values of 5,900, 6,000 and 6,000, re-
spectively. After completion of the series of polymer-
ization reactions continuously conducted for 600 hours,
- no accumulation of low molecular weight polymer and the
like was observed on the foraminous plate in the wire-
wetting fall polymerizer.
Example 11
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 6. The system of
Fig. 6 comprises a wall-wetting fall polymerization,
and first stage and second stage wire-wetting fall
- 119 --
2168630
polymerizations.
In the wall-wetting fall polymerization, wall-
wetting fall polymerizer 504 was used. Wall-wetting
fall polymerizer 504 had a tube having an inner wall
surface area of 2 m2.
In the first stage wire-wetting fall polymeriza-
tion, first wire-wetting fall polymerizer llOA was
used. In the second stage wire-wetting fall polymeri-
zation, second wire-wetting fall polymerizer llOB was
used. Each of the first and second wire-wetting fall
polymerizers is equipped with a foraminous plate which
has 20 holes ha~ing a diameter of 7 mm and arranged in
a zigzag configuration. In each of the first and
second wire-wetting fall polymerizers, 20 strands of
1.0 mm~ SUS 316 wires are hung vertically from the
respecti~e holes of the foraminous plate to a reservoir
portion at the bottom of the wire-wetting fall polymer-
izer, wherein each wire is secured in the same manner
as described in Example 1 and shown in Fig. 10. In
each of the first and second wire-wetting fall polymer-
izers, the wire-wetting fall distance is 8 m.
A molten mixture of bisphenol A and diphenyl
carbonate (molar ratio of 1:1.03) was continuously fed
through inlet 501 and recirculation line 502 at a flow
rate of 3 liters/hr and introduced through overflow
- 120 -
2168630
port 503 into the wall-wetting fall polymerization
reaction zone, thereby effecting a wall-wetting fall
polymerization. The introduced molten mixture fell
along and in contact with the inner wall of the tube in
the form of film-like prepolymer 505. The reaction
conditions of the wall-wetting fall polymerization were
as follows: the reaction temperature was 240 C, and
the reaction pressure was 40 mmHg. A part of the
resultant prepolymer 509 at the bottom of wall-wetting
fall polymerizer 504 was recirculated to overflow port
503 of wall-wetting fall polymerizer 504 through recir-
culation line 502 at a recirculation rate of 600 lit-
ers/hr and introduced to wall-wetting fall polymerizer
504.
When the volume of prepolymer 509 at the bottom of
wall-wetting fall polymerizer 504 reached 10 liters,
part of prepolymer 509 was continuously fed to first
wire-wetting fall polymerizer llOA so that the volume
of prepolymer 509 in wall-wetting fall polymerizer 504
was constantly maintained at 10 liters. The feeding of
prepolymer 509 to first wire-wetting fall polymerizer
llOA was conducted through inlet lOlA provided in
recirculation line 102A for wire-wetting fall polymer-
izer llOA.
In first wire-wetting fall polymerizer llOA, a
- 121 -
2168630
wire-wetting fall polymerization of prepolymer 509 was
continuously carried out under polymerization reaction
conditions wherein the reaction temperature was 250 C,
and the reaction pressure was 5.0 mmHg, thereby obtain-
ing prepolymer lllA, while recirculating a part of
obtained prepolymer lllA to the feeding zone (having
foraminous plate 103A) of first wire-wetting fall
polymerizer llOA through recirculation line 102A at a
recirculation rate of 100 liters/hr.
When the volume of prepolymer lllA at the bottom
of first wire-wetting fall polymerizer llOA reached 10
liters, part of prepolymer lllA was continuously fed to
second wire-wetting fall polymerizer llOB so that the
volume of prepolymer lllA in first wire-wetting fall
polymerizer llOA was constantly maintained at 10 lit-
ers.
In second wire-wetting fall polymerizer llOB, a
wire-wetting fall polymerization reaction was continu-
ously carried out under polymerization reaction condi-
tions wherein the reaction temperature was 280 C, and
the reaction pressure was 0.8 mmHg, thereby obtaining
polymer lllB, while recirculating a part of obtained
prepolymer lllB to the feeding zone (having foraminous
plate 103B) of second wire-wetting fall polymerizer
llOB through recirculation line 102B at a recirculation
- 122 -
2168630
rate of 30 liters/hr.
When the volume of polymer lllB at the bottom of
second wire-wetting fall polymerizer llOB reached 10
liters, polymer lllB was continuously withdrawn from
second wire-wetting fall polymerizer llOB through
outlet lO9B by means of discharge pump 108B so that the
volume of polymer lllB in second wire-wetting fall
polymerizer llOB was constantly maintained at 10 lit-
ers.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
~amples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b*-values of 3.2, 3.3 and 3.2, respective-
ly, and had Mn values of 8,200, 8,200 and 8,100, re-
spectively. After completion of the series of polymer-
ization reactions continuously conducted for 600 hours,
no accumulation of low molecular weight polymer and the
like was observed on the foraminous plate in each of
the first and second wire-wetting fall polymerizers.
Example 12
- 123 -
2168630
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 7. The system of
Fig. 7 comprises first stage and second stage agitation
polymerizations, a free-fall polymerization, and a
wire-wetting fall polymerization.
In the first stage agitation polymerization, a
couple of first agitation type polymerizer vessels 303A
and 303B were used. In the second stage agitation
polymerization, second agitation type polymerizer
vessel 303C was used. The capacity of each of first
agitation type polymerizer vessels 303A and 303B was
100 liters, and the capacity of second agitation type
polymerizer vessel 303C was 50 liters. The agitating
blades of each of these three agitation type polymeriz-
er vessels were of anchor type.
In the free-fall polymerization, free-fall poly-
merizer 210 was used. Free-fall polymerizer 210 is
equipped with a perforated plate which has 50 holes
~ having a diameter of 3 mm and arranged in a zigzag
configuration. Free-fall polymerizer 210 had recircu-
lation line 202. The free-fall distance is 4 m.
In the wire-wetting fall polymerization, wire-
wetting fall polymerizer 110 was used. Wire-wetting
fall polymerizer 110 is equipped with a foraminous
plate which has 20 holes having a diameter of 5 mm and
- 124 -
2168630
arranged in a zigzag configuration. In wire-wetting
fall polymerizer 110, 20 strands of 0.8 mm~ SUS 316
wires are hung vertically from the respective holes of
foraminous plate 103 to a reservoir portion at the
bottom of wire-wetting fall polymerizer 110, wherein
each wire is secured in the same manner as described in
Example 1 and shown in Fig. 10. In wire-wetting fall
polymerizer 110, the wire-wetting fall distance is 6 m.
The first stage agitation polymerization in first
agitation type polymerizer vessels 303A and 303B was
batchwise conducted, whereas the second stage agitation
polymerization in second agitation type polymerizer
vessel 303C, the free-fall polymerization in free-fall
polymerizer 210, and the wire-wetting fall polymeriza-
tion in wire-wetting fall polymerizer 110, were contin-
uously conducted.
The polymerization reaction conditions in both of
first agitation type polymerizer vessels 303A and 303B
were as follows: the reaction temperature was 180 C,
the reaction pressure was atmospheric pressure, and the
flow rate of nitrogen gas was 0.5 liter/hr.
In operation, 80 kg of a monomer mixture of bis-
phenol A and diphenyl carbonate in a molar ratio of
1:1.05 was charged into each of first agitation type
polymerizer vessels 303A and 303B. The monomer mixture
- 125 -
2168630
in polymerizer 303A was polymerized in a molten state
while agitating for 4 hours to obtain prepolymer 304A.
Outlet 305A was opened, and prepolymer 304A was fed to
second agitation type polymerizer vessel 303C at a flow
rate of 3 liters/hr.
While feeding prepolymer 304A obtained in first
agitation type polymerizer vessel 303A to second agita-
tion type polymerizer vessel 303C, first agitation type
polymerizer vessel 303B was operated and the monomer
mixture of bisphenol A and diphenyl carbonate was
polymerized in the same manner as in the agitation
polymerization in first agitation type polymerizer
vessel 303A, to obtain prepolymer 304B.
When first agitation type polymerizer vessel 303A
became empty, outlet 305A of polymerizer 303A was
closed and, instead, outlet 305B of polymerizer 303B
was opened, so that prepolymer 304B was fed from first
agitation type polymerizer vessel 303B to second agita-
tion type polymerizer vessel 303C at a flow rate of 3
liters/hr. In this instance, the same monomer mixture
of bisphenol A and diphenyl carbonate as mentioned
above was charged in polymerizer 303A. While feeding
prepolymer 304B obtained in first agitation type poly-
merizer vessel 303B to second agitation type polymeriz-
er vessel 303C, polymerizer vessel 303A was operated,
- 126 -
21686~0
so that the monomer mixture charged therein was poly-
merized in the same manner as mentioned above.
With respect to the batchwise polymerization in
first agitation type polymerizer vessels 303A and 303B
and to the alternate feedings of prepolymers 304A and
304B from polymerizers 303A and 303B to second agita-
tion type polymerizer vessel 303C, the same operation
as mentioned above was repeated, so that the prepolymer
(either prepolymer 304A or prepolymer 304B, alternate-
ly) was continuously fed to second agitation type
polymerizer vessel 303C.
In second agitation type polymerizer vessel 303C,
a further agitation polymerization of prepolymers 304A
and 304B, alternately fed from first agitation type
polymerizer vessels 303A and 303B, was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 240 C, the reac-
- tion pressure was 60 mmHg and the flow rate of nitrogen
gas was 1 liter/hr, thereby obt~; n i ng prepolymer 304C .
When the volume of prepolymer 304C in second
agitation type polymerizer vessel 303C reached 20
liters, part of prepolymer 304C was continuously fed to
free-fall polymerizer 210 so that the volume of prepol-
ymer 304C in second agitation type polymerizer vessel
303C was constantly maintained at 20 liters. The
- 127 -
2168630
feeding of prepolymer 304C to free-fall polymerizer 210
was conducted through inlet 201 provided in recircula-
tion line 202 for polymerizer 210.
In free-fall polymerizer 210, a free-fall polymer-
ization of prepolymer 304C was continuously carried out
under polymerization reaction conditions wherein the
reaction temperature was 250 C, and the reaction
pressure was 3.0 mmHg, thereby obt~;n;ng prepolymer
211, while recirculating a part of obtained prepolymer
- 211 to the introduction zone (having perforated plate
203) of free-fall polymerizer 210 through recirculation
line 202 at a recirculation rate of 100 liters/hr.
When the volume of prepolymer 211 at the bottom of
free-fall polymerizer 210 reached 10 liters, part of
prepolymer 211 was continuously fed to wire-wetting
fall polymerizer 110 so that the volume of prepolymer
211 in free-fall polymerizer 210 was constantly main-
tained at 10 liters.
In wire-wetting fall poIymerizer 110, a wire- -
wetting fall polymerization reaction was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 280 C, and the
reaction pressure was 0.4 mmHg, thereby obtaining
polymer 111.
When the volume of polymer 111 at the bottom of
- 128 -
2168630
wire-wetting fall polymerizer 110 reached 10 liters,
polymer 111 was continuously withdrawn from wire-wet-
ting fall polymerizer 110 through outlet 109 by means
of discharge pump 108 so that the volume of polymer 111
in wire-wetting fall polymerizer 110 was constantly
maintained at 10 liters.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b*-values of 3.3, 3.3 and 3.2, respective-
ly, and had Mn values of 9,900, 10,000 and 10,000,
respectively. After completion of the series of poly-
merization reactions continuously conducted for 600
hours, no accumulation of low molecular weight polymer
and the like was observed on the perforated plate in
the free-fall polymerizer and the foraminous plate in
the wall-wetting fall polymerizer.
Example 13
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 8. The system of
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Fig. 8 comprises first stage, second stage and third
stage agitation polymerizations, and a wire-wetting
fall polymerization.
In the first stage agitation polymerization, a
couple of first agitation type polymerizer vessels 303A
and 303B were used. In the second stage agitation
polymerization, second agitation type polymerizer
vessel 303C was used. The capacity of each of first
agitation type polymerizer vessels 303A and 303B was
- lO0 liters, and the capacity of second agitation type
polymerizer vessel 303C was 50 liters. The agitating
blades of each of these three agitation type polymeriz-
er vessels were of anchor type.
In the third agitation polymerization, horizontal
agitation type polymerizer 401 was used. Horizontal
agitation type polymerizer 401 had a capacity of 30
liters, an L/D ratio of 6, and a twin-screw agitator
having a rotation diameter of 140 mm.
~ In the wire-wetting fall polymerization, wire-
wetting fall polymerizer 110 was used. Wire-wetting
fall polymerizer 110 is equipped with a foraminous
plate which has 20 holes having a diameter of 7 mm and
arranged in a zigzag configuration. In wire-wetting
fall polymerizer 110, 20 strands of 0.8 mm~ SUS 316
wires are hung vertically from the respective holes of
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foraminous plate 103 to a reservoir at the-bottom of
wire-wetting fall polymerizer 110, wherein each wire is
secured in the same manner as described in Example 1
and shown in Fig. 10. In wire-wetting fall polymerizer
110, the fall distance is 8 m.
The first stage agitation polymerization in first
agitation type polymerizer vessels 303A and 303B was
batchwise conducted, whereas the second stage agitation
polymerization in second agitation type polymerizer
vessel 303C, the third stage agitation polymerization
in horizontal agitation type polymerizer 401, and the
wire-wetting fall polymerization in wire-wetting fall
polymerizer 110, were continuously conducted.
The polymerization reaction conditions in both of
first agitation type polymerizer vessels 303A and 303B
were as follows: the reaction temperature was 180 C,
the reaction pressure was atmospheric pressure, and the
- flow rate of nitrogen gas was 0. 5 liter/hr. ~
In operation, 80 kg of a monomer mixture of bis-
phenol A and diphenyl carbonate in a molar ratio of
1:1.02 was charged into each of first agitation type
polymerizer vessels 303A and 303B. The monomer mixture
in polymerizer 303A was polymerized in a molten state
while agitating for 4 hours to obtain prepolymer 304A.
Outlet 305A was opened, and prepolymer 304A was fed to
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second agitation type polymerizer vessel 3Q3C at a flow
rate of 5 liters/hr.
While feeding prepolymer 304A obtained in first
agitation type polymerizer vessel 303A to second agita-
tion type polymerizer vessel 303C, first agitation type
polymerizer vessel 303B was operated and the monomer
mixture of bisphenol A and diphenyl carbonate was
polymerized in the same manner as in the agitation
polymerization in first agitation type polymerizer
vessel 303A, to obtain prepolymer 304B.
When first agitation type polymerizer vessel 303A
became empty, outlet 305A of polymerizer 303A was
closed and, instead, outlet 305B of polymerizer 303B
was opened, so that prepolymer 304B was fed from first
agitation type polymerizer vessel 303B to second agita-
tion type polymerizer vessel 303C at a flow rate of 5
liters/hr. In this instance, the same monomer mixture
of bisphenol A and diphenyl carbonate as mentioned
above was charged in polymerizer 303A. While feeding
prepolymer 304B obtained in first agitation type poly-
merizer vessel 303B to second agitation type polymeriz-
er vessel 303C, polymerizer vessel 303A was operated,
so that the monomer mixture charged therein was poly-
merized in the same manner as mentioned above.
With respect to the batchwise polymerization in
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first agitation type polymerizer vessels 303A and 303B
and to the alternate feeding of prepolymers 304A and
304B from polymerizers 303A and 303B to second agita-
tion type polymerizer vessel 303C, the same operation
as mentioned above was repeated, so that the prepolymer
(either prepolymer 304A or prepolymer 304B, alternate-
ly) was continuously fed to second agitation type
polymerizer vessel 303C.
In second agitation type polymerizer vessel 303C,
a further agitation polymerization of prepolymers 304A
and 304B, alternately fed from first agitation type
polymerizer vessels 303A and 303B, was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 240C, the reac-
tion pressure was 60 mmHg and the flow rate of nitrogen
gas was 1 liter/hr, thereby obt~;ning prepolymer 304C.
When the volume of prepolymer 304C in second
agitation type polymerizer vessel 303C reached. 20
liters, part of prepolymer 304C was continuously fed to
horizontal agitation type polymerizer 401so that the
volume of prepolymer 304C in second agitation type
polymerizer vessel 303C was constantly maintained at 20
liters. The feeding of prepolymer 304C to horizontal
agitation type polymerizer 401 was conducted through
inlet 402 of polymerizer 401.
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In horizontal agitation type polymerizer 401, an
agitation polymerization of prepolymer 304C was contin-
uously carried out under polymerization reaction condi-
tions wherein the reaction temperature was 260 C, and
the reaction pressure was 12 mmHg, thereby obtaining a
prepolymer.
When the volume of the obtained prepolymer in
horizontal agitation type polymerizer 401 reached 15
liters, part of the obtained prepolymer was continuous-
ly fed to wire-wetting fall polymerizer 110 so that the
volume of the obtained prepolymer in horizontal agita-
tion type polymerizer 401 was constantly maintained at
15 liters.
In wire-wetting fall polymerizer 110, a wire-
wetting fall polymerization reaction was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 280 C, and the
reaction pressure was 0.3 mmHg, thereby obtaining
~ polymer 111.
When the volume of polymer 111 at the bottom of
wire-wetting fall polymerizer 110 reached 10 liters,
polymer 111 was continuously withdrawn from wire-wet-
ting fall polymerizer 110 through outlet 109 by means
of discharge pump 108 so that the volume of polymer 111
in wire-wetting fall polymerizer 110 was constantly
_ 134 -
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maintained at 10 liters.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b -values of 3.3, 3.4 and 3.4, respective-
ly, and Mn values of 8,100, 8,000 and 8,000, respec-
tively. After completion of the series of polymeriza-
tion reactions continuously conducted for 600 hours, no
accumulation of low molecular weight polymer and the
like was observed on the foraminous plate in wire-
wetting fall polymerizer 110.
Example 14
An aromatic polycarbonate was produced in accord-
ance with a system as shown in Fig. 9. The system of
Fig. 9 comprises first stage and second stage agitation
polymerizations, a wall-wetting fall polymerization,
and first stage and second stage wire-wetting fall
polymerizations.
In the first stage agitation polymerization, a
couple of first agitation type polymerizer vessels 303A
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-
and 303B were used. In the second stage agitation
polymerization, second agitation type polymerizer
vessel 303C was used. The capacity of each of first
agitation type polymerizer vessels 303A and 303B was
lO0 liters, and the capacity of second agitation type
polymerizer vessel 303C was 50 liters. The agitating
blades of each of these three agitation type polymeriz-
er vessels were of anchor type.
In the wall-wetting fall polymerization, wall-
wetting fall polymerizer 504 was used. Wall-wetting
fall polymerizer 504 had a tube having an inner wall
surface area of 2 m2.
In the first stage wire-wetting fall polymeriza-
tion, first wire-wetting fall polymerizer llOA was
used. In the second stage wire-wetting fall polymeri-
zation, second wire-wetting fall polymerizer llOB was
used. Each of the first and second wire-wetting fall
polymerizers is equipped with a foraminous plate which
has 20 holes having a diameter of 5 mm and arranged in
a zigzag configuration. In each of the first and
second wire-wetting fall polymerizers, 20 strands of
0.8 mm~ SUS 316 wires are hung vertically from the
respective holes of the foraminous plate to a reservoir
portion at the bottom of the wire-wetting fall polymer-
izer, wherein each wire is secured in the same manner
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as described in Example 1 and shown in Fig. 10. In
each of the first and second wire-wetting fall polymer-
izers, the wire-wetting fall distance is 6 m.
The first stage agitation polymerization in first
agitation type polymerizer vessels 303A and 303B was
batchwise conducted, whereas the second stage agitation
polymerization in second agitation type polymerizer
vessel 303C, the wall-wetting fall polymerization in
wall-wetting fall polymerizer 504, the first stage
wire-wetting fall poIymerization in first stage wire-
wetting fall polymerizer llOA and the second stage
wire-wetting fall polymerization in second stage wire-
wetting fall polymerizer llOB were continuously con-
ducted.
The polymerization reaction conditions in both of
first agitation type polymerizer vessels 303A and 303B
were as follows: the reaction temperature was 180 C,
the reaction pressure was atmospheric pressure, and the
flow rate of nitrogen gas was 0.5 liter/hr.
In operation, 80 kg of a monome,r mixture of bis-
phenol A and diphenyl carbonate in a molar ratio of
1:1.05 was charged into each of first agitation type
polymerizer vessels 303A and 303B. The monomer mixture
in polymerizer 303A was polymerized in a molten state
while agitating for 4 hours to obtain prepolymer 304A.
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Outlet 305A was opened, and prepolymer 304A was fed to
second agitation type polymerizer vessel 303C at a flow
rate of 4 liters/hr.
While feeding prepolymer 304A obtained in first
agitation type polymerizer vessel 303A to second agita-
tion type polymerizer vessel 303C, first agitation type
polymerizer vessel 303B was operated and the monomer
mixture of bisphenol A and diphenyl carbonate was
polymerized in the same manner as in the agitation
polymerization in first agitation type polymerizer
vessel 303A, to obtain prepolymer 304B.
When first agitation type polymerizer vessel 303A
became empty, outlet 305A of polymerizer 303A was
closed and, instead, outlet 305B of polymerizer 303B
was opened, so that prepolymer 304B was fed from first
agitation type polymerizer vessel 303B to second agita-
tion type polymerizer vessel 303C at a flow rate of 4
liters/hr. In this instance, the same monomer mixture
of bisphenol A and diphenyl carbonate as mentioned
above was charged in polymerizer 303A. While feeding
prepolymer 304B obtained in first agitation type poly-
merizer vessel 303B to second agitation type polymeriz-
er vessel 303C, polymerizer vessel 303A was operated,
so that the monomer mixture charged therein was poly-
merized in the same manner as mentioned above.
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2168630
With respect to the batchwise polymerization in
first agitation type polymerizer vessels 303A and 303B
and to the alternate feeding of prepolymers 304A and
304B from polymerizers 303A and 303B to second agita-
tion type polymerizer vessel 303C, the same operation
as mentioned above was repeated, so that the prepolymer
(either prepolymer 304A or prepolymer 304B, alternate-
ly) was continuously fed to second agitation type
polymerizer vessel 303C.
In second agitation type polymerizer vessel 303C,
a further agitation polymerization of prepolymers 304A
and 304B, alternately fed from first agitation type
polymerizer vessels 303A and 303B, was continuously
carried out under polymerization reaction conditions
wherein the reaction temperature was 240 C, the reac-
tion pressure was 60 mmHg and the flow rate of nitrogen
gas was 1 liter/hr, thereby obtaining prepolymer 304C.
When the volume of prepolymer 304C in second
agitation type polymerizer vessel 303C reached 20
liters, part of prepolymer 304C was continuously fed to
wall-wetting fall polymerizer 504 so that the volume of
prepolymer 304C in second agitation type polymerizer
vessel 303C was constantly maintained at 20 liters.
The feeding of prepolymer 304C to wall-wetting fall
polymerizer 504 was conducted through inlet 501 provid-
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ed in recirculation line 502 for wall-wetting fall
polymerizer 504.
In wall-wetting fall polymerizer 504, a wall-
wetting fall polymerization of prepolymer 304C was
continuously carried out under polymerization reaction
conditions wherein the reaction temperature was 250 C,
and the reaction pressure was 4 mmHg, thereby obtaining
prepolymer 509, while recirculating a part of obtained
prepolymer 509 to overflow port 503 of wall-wetting
fall polymerizer 504 through recirculation line 502 at
a recirculation rate of 100 liters/hr.
When the volume of prepolymer 509 at the bottom of
wall-wetting fall polymerizer 504 reached 10 liters,
part of prepolymer 509 was continuously fed to first
stage wire-wetting fall polymerizer llOA so that the
volume of prepolymer 509 in wall-wetting fall polymer-
izer 504 was constantly maintained at 10 liters.
In first wire-wetting fall polymerizer IlOA, a
wire-wetting fall polymerization of prepolymer 509 was
continuously carried out under polymerization reaction
conditions wherein the reaction temperature was 260 C,
and the reaction pressure was 1 mmHg, thereby obtain-
ing prepolymer lllA, while recirculating a part of
obtained prepolymer lllA to the feeding zone (having
foraminous plate 103A) of first wire-wetting fall
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2168630
polymerizer llOA through recirculation line 102A at a
recirculation rate of 20 liters/hr.
When the volume of prepolymer lllA at the bottom
of first wire-wetting fall polymerizer llOA reached 10
liters, part of prepolymer lllA was continuously fed to
second wire-wetting fall polymerizer llOB so that the
volume of prepolymer lllA in first wire-wetting fall
polymerizer llOA was constantly maintained at 10 lit-
ers.
~ In second wire-wetting fall polymerizer llOB, a
wire-wetting fall polymerization reaction was continu-
ously carried out under polymerization reaction condi-
tions wherein the reaction temperature was 280 C, and
the reaction pressure was 0.3 mmHg, thereby obtaining
polymer lllB.
When the volume of polymer lllB at the bottom of
wire-wetting fall polymerizer llOB reached 10 liters,
polymer lllB was continuously withdrawn from-second
stage wire-wetting fall polymerizer llOB through outlet
lO9B by means of discharge pump 108B so that the volume
of polymer lllB in second stage wire-wetting fall
polymerizer llOB was constantly maintained at 10 lit-
ers.
The above-mentioned series of polymerization
reactions was continuously carried out for 600 hours.
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Samples were taken from the produced aromatic polycar-
bonates which were withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
polymerization reaction. The samples of the produced
aromatic polycarbonates withdrawn at time points of 200
hours, 400 hours and 600 hours after the start of the
reaction had b -values of 3.4, 3.3 and 3.3, respective-
ly, and Mn values of 11,900, 12,000 and 12,000, respec-
tively. After completion of the series of polymeriza-
tion reactions continuously conducted for 600 hours, no
accumulation of low molecular weight polymer and the
like was observed on the foraminous plate in each of
the first and second wire-wetting fall polymerizers.
Examples 15 to 18
In accordance with the same system as employed in
Example 14 and shown in Fig. 9, a series of polymeriza-
tion reactions was individually conducted in substan-
tially the same manner as in Example 14, except that a
monomer mixture of bisphenol A and an aromatic dihy-
droxy compound (shown in Table 2) other than bisphenol
A in a molar ratio of 1:1 was used instead of the
bisphenol A. In each of Examples 15 to 18, the monomer
mixture was used in an equimolar amount to the bisphe-
nol A used in Example 14. Results are shown in Table
2.
- 142 -
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Table 1
Ex. 2 Ex. 3 Ex. 4 Ex. 5
Molecular weight of 7,8007,000 g,000 5,000
prepolymer
Flow rate of prepolymer 5 10 6 30
Flow rate of prepolymer per 0.5 1 0.6 3
hole (liter/hr)
Reaction temperature (C) 250 265 280 250
Reaction pressure (mmHg) 0.3 0.7 0.3 1.0
-Flow rate of nitrogen gas 0 1 2 0
(liter/hr)
Mn 9,9009,200 12,500 6,200
200 hrs
b*-value 3.3 3.3 3.3 3.3
Mn 10,0009,100 12,500 6,100
400 hrs
b*-value 3.3 3.3 3.3 3.2
Aroma-
tic Mn 10,0009,200 12,400 6,100
poly- 600 hrs
carbo- b*-value 3.3 3.3 3.3 3.2
nates
Mn 9,9009,100 12,600 6,200
800 hrs
b*-value 3.3 3.3 3.3 . 3.3
Mn 10,0009,100 12,500 6,200
1,000 hrs
b*-value 3.3 3.3 3.3 3.3
- 143 -
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Table 2
Aromatic polycarbonate
(obtained after 600-hr
Aromatic dihydroxy polymerization reactions)
compound other than
bisphenol A
b*-value Mn
Ex~ S ~ OH 3.3 10,300
16HO ~ SO2 ~ 0H 3.3 11,400
CH3 CH3
liHO ~ c ~ OH 3.4 10,900
CH3 0 CH3
CH3 CH3
18HO ~ CH2 ~ 0H 3.4 12,100
CH3 CH~
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