Note: Descriptions are shown in the official language in which they were submitted.
~ 7~;35 20375-527E
This is a divisional application of Serial No~ 485,040
filed June 25, 1985.
A first aspect of this application provides a para-
phenylene sulfide block copolymer comprising a recurring unit
~ S ) . The recurring unit is present in the form of a
block of 20 to 5,000 units on the average in the molecular chain
and the mol fraction of the recurring units is in the range of
0.50 to 0.98.
A second aspect of this application pxovides a molded
article produced from such a para-phenylene sulfide block copolymer.
A third aspect of this application provides a printed
circuit board composed of [i] an insulating base plate made from
a composite of 50 to 95 volume ~ of a polymer mainly comprising
such a para-phenylene sulfide block copolymer and 5 to 50 volume
~ of à fibrous reinforcing material and [~ a metal layer of
a circuit pattern formed on a surface of the base plate.
It should be noted that the term "present lnvention"
in the following description includes the subject matters of
this divisional application, of the parent application and of
two more di~visional applications divided out from the same parent
application.
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20375-527E
BACKGROUND OF TliE INVENTION
1. Fiela of the Art:
The present invention relates to a p-phenylene
sulfide copolymer. More particularlyf the invention
relates to a crystalline p-phenylene sulfide block
copolymer comprising a block of p-phenylene sulfide
recurring units (- ~ -S~ in the molecular chain.
2. Prior ~rt:
Concerning p-phenylene sulfide polymers, there
have been numerous report~ on p~phenylene ~ulfide
homopolymers ~as di#closed in the speci~ications of
Japanese Patent Publications Nos.12240/1977 and 3368/
1970 a~d Japan2se Patent Laid-Open No.22926/19B4).
Also, some reports aan be ound Otl p-phenylene sul-
fiae random copol~mers (a~ described, ~or exampl~, in
the specification of U.S. Patent No.3,869,434~,
The p-phenylene sulfiae homopolymers have been
used as heat resi3tant thermoplastic resins mainly in
in~ection molding procssses since the highly ~rystal-
line p-phenylene sulfide homopolymers can be used at
a temperature as high as nearly their crystalline
melting point (about 285C) when they are hi~hly
crystallized. ~lowever, these polymers have been
accompanied by the problems o~ excessively hi~h
1a-
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crystallization rate in the melt process and ready
formation of rough spherulites. That is, when films
are to be formed from them by an inflation method,
they are crystallized and solidified prior to sufficient
inflation, whereby it is difficult to form intended
stretched and oriented films. In extrusion molding
by means of a T-die to form a sheet, the crystal-
lization and solidifying occur prior to the ~inding of
the sheet around a wind-up roll, whereby it is dif-
ficul; to obtain a smooth sheet having a uniformthickness. In melt extrusion to form pipes, rough
spherulites are formed prior to the quench to make
it difficult to obtain the tough extrusion moldings.
In melt coating of electric wires, xough spherulites
are formed in the coating film to make it difficult
to obtain touyh coating films. In the production of
fibers by melt spinning process, the crystallization and
solidifying proceed in the course of the melt spinning
operation to make sufficient stretch and orientation
impossible, and, therefore, tough fibers cannot
easily be obtained.
While the p-phenylene sulfide random copolymers,
which are ge~erally non-crystalline, have a character-
istic feature of being melt-processed quite easily,
since they are not crystalli~ed or solidified in the course
of the melt spinning operation, they are problematic
in that their hea~ resistance is extremely poor due to
--2--
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the non-crystallizability.
Printed circuit boards composed of an insulating
base and a metal layer of a circuit pattern formed on
the surface thereof have been used widely in the field
of electronic appliances.
As the ins~lating materials for the printed cir
cuit boards, composites of thermosetting resins, such
as epoxy, phenolic and unsaturated polyester resins,
with fibrous reinforcing materials, such as glass
fibers, synthetic fibers and paper, have been mainly
used. However, these matexials are problematic in
that a long time is necessary for recovery of the
solvent and curing of the resin and in that they have
a high hygroscopicity and only a poor resistance to
CAF ~conducti~e anodic fiber growth).
Recently, attempts were made to use ;a composite
of poly~p-phenylene sulfide which is a thermoplastic
resin and a fibrous reinforcing material for the
production of insulating bases for printed circuit
boards ~as described in the specifications of Japanese
Patent Laid-Open Nos. 96588fl982 and 3991/1984).
However, the insulating base comprising the poly-p-
phenylene sulfide has insufficient adhesion to the
metal layer, and, therefore, the metal layer is
easily peeled off.
Electronic components such as IC, transistors,
diodes and capacitors have been sealed with or
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20375-527
encapsulated within a synthetic resin or ceramic
substance for the purposes of preven-ting changes in
the properties due to the external atmosphere,
preventing deformation, ancl maintaining the electrical
insulating property.
The sealing resins used heretofore include
thermosetting resins, particularly, epoxy and
silicone resins. ~Iowever, these resins have the
following defects: (1) the molding time is prolonged,
since a long time is necessary for the thermoset-ting,
(2) a long post-curing time is required, (3) as the
molding shot number is increased, contamination of
the mold accumulates, (~) the resin is easily de-teriorated
during storage and (5) unnecessary portions like runnex
gates of the moldings cannot be reused.
For overcoming the above mentioned drawbacks,
processes wherein poly-p-phenylene sulfide (a thermo~
plastic resin) is used have been proposed (as
described, ~or example, i~ the specifications of
~apanese Patent Puhlication No.2790/1981 and Japanese
Patent Laid-Open Nos.22363/1978, 81957/~981, 20910/
198~ and 20911/198~).
When poly-p-phenylene sul~ide is used, the seal-
ing or encapsulation is conducted ordinarily by a melt
molding process. In this process, the crystallization
proceeds rapidly to ~orm rough spherulites in -the
step of solidifyin~ the molten resin. Therefore, a
.,
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marked molding shrinkage occurs in the resin layer, particularly
around the spherulites, to form cracks in the resin layer, to cut
or to deform the bonding wire, and to form a gap between the lead
frame or bonding wire and the resin layer. As a result, a problem
arises in the resulting electronic parts in that water penetrates
thereinto through the interface between the resin layer and the
lead frame or bonding wire to cause deterioration of the quality
of the electronic parts particularly at a high temperature in a
highly humidity atmosphere. To solve these problems, processes
wherein inorganic fillers or various additives are used have been
proposed. However, the problems cannot be solved essentially
unless the properties of the base resin are altered.
On the other hand, production of block copolymers is
disclosed in U.S. Patent 3,966,688. The method disclosed therein
may comprise reacting a poly-_-phenylene sulfide with a poly-m-
phenylene sulfide in a solvent, to form a block copolymers.
SUMMARY OF THE INVENTION
According to the present invention, the problems of
excessively high crystallization rate and rough spherulite-forminy
property-of the p-phenylene sulfide homopolymers and also non~
crystallizability and poor heat resistance of the p-phenylene
--5--
sulfide random copolymers are solved. The present inventlon
provides a phenylene sulfide polymer hav:ing e~ce.llent crystallin-
ity, heat reslstance and easy melt-processability. That is, the
present invention provides a crystalline phenylene sulfide polymer
suitable particularly for the inflation film-forming process,
melt extrusion molding, electric wire coating, melt spinning and
stretching.
The phenylene sulfide polymer according to the present
invention is a para-phenylene sulfide block copolymer consisting
essentially of recurring units (A) ~ S-~ and recurring unit
(B) ~ o ~ S-~, said recurring units (A) being present in the form
of a b ck of 20 to 5,000 units thereof on the average in the
molecular chain, characterized in that the mol fraction of the
recurring units (~) is in the range of 0.50 to O.g8, and the
copolymer has a melt viscosity (~*) of 50 to 100,000 poise,
preferably of l,000 to 50,000 poise, which.is hereinbelow
indicated as P, as determined at 310C at a shear rate of 200
sec~1 and physical properties which will be described herein-
after.
According to this inven-tion in another aspect thereof,
there is provided a process for producing the p-phenylene sul~ide
r j ,~ r~
block copolymer clescribed above which process comprises a first
step of heating an aprotic polar organic solvent containing a
p-dihalobenzene and an alkali metal sulfide to form a reaction
liquid mixture ~C) containing a p-phenylene sulfide polymer con-
sisting essentially of recurring units (A) ~ S-~ and a
second step of adding a dihaloaromatic compound consisting essen-
tially of a m~dihalobenzene to the reaction liquid mixture 5C) and
heating the mixture in -the presence of an alkali metal sulfide and
an aprotic polar organic solvent to form a block copolymer consis-
ting essentially of a block consisting essentially of the recur-
ring units (A) and a block consisting essentially of recurring
units (B) ( ~ - S-~, wherein: the reaction in the first step
is carried out until the degree of polymerization of the recurring
units (A) has become 20 to 5,000 on the average; the reaction in
the second step is carried out until the mol fraction (X) of the
recurring units (A) in the resulting block.copolymer has become
0.50 to 0.98; and the reactions in these steps are carried out so
that the resulting p-phenylene sulfide block copolylner will have a
melt viscosity (~*) measured under conditions oE 310C/200 sec~
of 50 to 100,000 P, preferably 1,000 to 50,000 P, and physical
~;~'7~
20375-527
properties which will be described hereinafter.
Another mode of practice of the process of the present
invention for producing the p-phenylene sulfide block copolymer
described above comprises a first step of heating an aprotic polar
organic solvent containing a dihaloaromatic compound consisting
essentially of a m-dihalobenzene and an alkali metal sulfide to
form a reaction liquid mixture (E~ containing a m-phenylene
sulfide polymer consisting essentially of recurring units
(B) ( ~ - S-~ and a second step of adding a p-dihaloben~ene to
the reactlon liquid (E) and heating the mixture in the presence of
an alkali metal sulfide and an aprotic polar organic solvent to
form a block copolymer consisting essentially of the recurring
. ~ .
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20375-527
units (B) and recurring units (A) ~ ~ ~ S-~, wherein: the
reaction in the first step is carried out until the average degree
of polymerization of at least 2 and in the range of (20 x 1
to (5,000 x 1 - X) where X represents a mol fraction of the
recurring units (A) in the resulting block copolymer which is in
the range of 0.50 to 0.98 has been obtained; the reaction in the
second step is carried out until the mol fraction (X) of the
recurring units (A) in the resulting block copolymer has become
0.50 to 0.98; and the reactions in these steps are carried out so
that the resulting p-phenylene sulfide block copolymer will have a
melt viscosity (~*) measured under conditions of 310C/200 sec~
of 50 to 100,000 P, preferably 1,000 to 50,000 P and physical
properties which will be described hereinafter.
~-Z 7~ q:~
20375-527
The above described p-phenylene sulfide bloc~
copolymer has the following physical properties:
~ a) a glass transition temperature (Tg) of 20
to 80C,
(b~ a crystalline meltiny point (~m) of 250
to 285C, and
(c) a crystailization index (Ci) of 15 to ~S,
this value being that of the heat~treated, but not
stretch-oriented copolymer.
The present invention in still another aspect
thereof also provides molded articles of the above
described p-phenylene sulfide block copolymer.
The present invention further relates to the
use of the b;ock copolymer for the production of a
printed circuit board.
The printed circuit board according to the pre-
sent invention is composed of an insulatin~ base
which i.s a molded plate comprising a composite of 50
to 95 vol. % of a polymer comprising mainly a pheny-
lene sulfide block copolymer and 5 to 50 vol. % of a
fibrous reinforcing material and a metal layer of a
circuit pattern formed on the surface of the base,
said phenylene sulfide block copolymer comprising 20
to 5,000 recurring uni-ts ~ -S-} on the average
in the molecular chain, said recurring units
S-~ having a mol fraction of 0.50 to 0.98 and
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said copolymer having a melt viscosity (~*) o~ 50 to 100,000 P,
preferably 300 to 50,000 P as determined at 310~C at a shear rate
of 200 sec~l and a crystalline melting point of 200 to 350C.
The present invention in a further aspect thereof
provides methods of use of the above mentioned block copolymer as
a starting material for a composition for sealing or encapulating
electronic parts.
The composition of the invention for sealing electronic
parts comprises 100 parts by weight of a synthetic resin component
and 20 to 300 parts by weight oE an inorganic filler, character-
ized in that the synthetic resin component comprises mainly a
phenylene sulfide block copolymer consisting essentially of recur-
ring units ~ ~ S-~ and recurring units -~- ~ S t wherein
the former recurring units ~orm a block having an average degree
of polymerization of 20 to 5,000, preferably 20 to 2,000 bonded in
the molecular chain and have a mol fraction in the range o~ 0.50
to 0.98, preferably 0.50 to 0.95, said copolymer ha~ing a melt
viscosity of 10 to 1500 P, preerably 50 to 1,500 P as determined
at 310C and at a shear rate of 200 sec~l.
A process for sealing or encapsulating electronic parts
is also presented according to the present invention, which
process is.characterized in that the electronic parts are sealed
by an injection molding method with a sealing composition co~pris-
--11--
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ing 100 parts by weight of a synthetic resin component and 20 to
300 parts by weight of an inorganic filler wherein the synthetic
resin component comprises mainly a phenylene sulEide block copoly-
mer consisting essentially of recurring units ~ S-) and
recurring units ( ~ S-~- in which the former recurring
units form a block having an average degree of polymerization of
20 to 5,000, pre~erably 20 to 2,000 bonded in the molecular chain
and have a mol ~raction in the range of 0.50 to 0.98, preferably
0.50 to 0.95, said copolymer having a melt viscosity of 10 to
1,500 P pre~erably 50 to 1,500 P (310C, shear rate: ~00 sec~l).
According to the block copolymers of the present inven-
tion, the problems of the melt processability of p-phenylene
sulfide homopolymer can be solved while the crystallizability and
heat resistance of the latter are maintained. The copolymers of
the present invention have a great characteristic processability
whereby they can well be molded in a temperature zone ranging from
the crystalline melting point (Tm) to the crystallization tempera-
ture on the higher temperature side (Tc2) (i.e., the temperature
at which the crystallization begins as the temperature is lowered
gradually from the molten state), i.e., in the supercooling
region. Therefore, the copolymers of the invention are suitable
for inflation molding, extrusion molding (production of sheets,
pipes, profiles, etc.), melt spinning and electric wire coating.
Other characteristic
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~0375-527
physical properties will be described below.
The phenylene sulfide bloc]c copolymers used as
the base resin in the present invention are free of
the afore-described problems of the phenylene sulfide
homopolymer, while retaining substantiall~ the
desirable characteristics of the cyrstalline homo-
polymer. The copolymers have a high adhesion to
metal layers.
Therefore, a printed circuit board comprising a
plate formed by molding a composite of the phenylene
sulfide block copolymer of the present invention
(base resin) and a fibrous reinforcing material and
a metal layer formed on the surface of the plate is
advantageous in that the metal layer has good adhesion
to the insulating base even when the layer is formed
by an additive method and in that it has also excel-
lent insulating properties and resistance to solder-
iny heat. Thus, the prlnted circultboard can be used
widely in the field of elec-tronic devices and appli-
ances.
The phenylene sulfide block copolymers used asthe base resin in the present invention are ree of
the afore-described problems of the phenylene sulfide
homopolymer, which retaining substantially the desir-
able characteristics of the crystalline homopolymer.Thus, these copolymers are suitable for sealing
electronic components.
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DETAILED DESCRIPTION OF THE INVENTION
Block Copolymers
Chemical structure of the copo~ymer
The crystalline p-phenylene sulfide block copoly-
mer according to the present invention is a high
molecular substance having such a chemical structure
that the recurring units (A) - ~ -S-~ in the form
of blocks are contained in the molecular chain.
According to our findings, it is necessary that
the p-phenylene sulfide recurring units (A) be dis-
tributed in the molecular chain in the form of a
block comprising 20 to 5,000, pre~erably 40 to 3,S00,
and particularly 100 to 2,000 units, on the average,
so that the copolymer can be processed easily in the
inf lation film-forming, melt-extrusion molding,
electric wire coating, melt spinning and stretching
processes while high heat resistance due to the
crystallinity of the p-phenylene sulfide homopolymer
is maintained. Copolymers wherein the recurring
units ~A) are distributed at random or wherein a
block comprising up to 20 recurring units (A) on
the average are distributed are not preferred since
the crystallinity as that of the p-phenylene sulfide
homopolymer is lost completely or partially, and the
heat resistance due ~o the crystallinity is lost.
On the other hand, when the recurrin~ units (A) are
distributed in the form of blocks comprising more
- ~14-
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than 5,000 units (A) on the average, the resulting
copolymer undesirably has substantially the same pro-
perties as those of the p-phenylene sulfide homo-
polymer.
It is necessary that the mol fraction X of the
recurring units (A) in the blocXs in the copolymer
molecular chain be in the range of 0.50 to 0.98,
preferably in the range of 0.60 to 0.90. When the
mol fraction of the p-phenylene sulfide recurring
units is controlled in this range, the resulting
copolymer has excellent processability in the steps
of inflation-film formation, melt extrusion, electric
wire coating and melt spinning and drawing while re-
taining the excellent crystallinity and heat resist-
ance peculiar to the p-phenylens sulfide homopolymer.
When the mol fraction of the recurring units (A)
exceeds 0.98, the effect of improving the proces-
sability becomes insufficient. On the other hand,
when it is less than 0.5, the crystallinity is reduced,
and, accordingly, the heat resistance is seriously
reduced. The mol fraction can be controlled easily
by varying the proportion of the stàrting materials
used in the pol~merization step.
The recurring units (B) which constitute the
block copolymer of the present invention together with
the p-phenylene sulfide resurring units ~A~ are
aryl~ne sulfide units -tAr-St- consisting essentially
-15~
-
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~7~53~
of m-phenylene sulfide recurriny units ~ S ) . In this
Eormula, Ar represents an aromatic compound residue. -~-Ar-S-~-
units other than the m-phenylene sulfide recurring units include:
_~ 5 ~. ~ > S ~ ~S ~ '
S ) ~ 0 - ~ S )~ and
~ ~ S-~-. Two or more of these recurring units can
be used together. The term "consisting essentially of m-phenylene
sulfide units B" used herein indicates that the amount of m-phen-
ylene sulfide units is at least 80 molar ~, preferably 90 to 100
molar %, based on the total recurring units (B).
The degree oE polymerization of the p~phenyl.ene sulfide
block copolymer accorcling to the present invention represented in
terms of melt viscosity ~* is 50 to 100,000 P, preferably 1,000 to
50,000 P. The melt viscosity ~* is determined by means of a Koka~
shiki flow tester at 310C and at a shear rate of 200 sec~l. When
the value of ~* is less than 50 P, the intended tough molded
article cannot be obtained, and when it exceeds 100,000 P/ the
molding operation becomes difficult.
The ~-phenylene sulfide block copolymers of higher mole-
cular weight, especially those whose ~* is 1,000 to 5,000 P are
-16-
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5~S
GUJ / J~
capable of producing tough products when processed into films,
fibers, injection molded products, extrusion-molded products and
electric wire coatings.
The number of the recurring units (A) ~ S~-~- in
the block copolymer according to the present
-16a-
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invention, i.e., the degree of polymerization of the
poly-p-phenylene sulfide block, can be determined by
a fluorescent X-ray method. The degree of polymer-
ization of the poly-m-phenylene sulfide block com-
ponents (B) can be measured by gel permeationchromatography (GPC). The mol fraction (X~ of the
poly-p-phenylene sulfide block components can be
determined easily by an infrared analysis.
Physical properties
The p-phenylene sulfide block copolymer of the
present invention has a glass transition temperature
(Tg) of 20 to 80C, a crystalline melting point (Tm)
of 250 to 285~C and a crystallization index (Ci) of
15 to 45 (this value being of the heat treated,
but non-stretched non-oriented copolymer sheet).
The block cop,olymer of the present invention
has a Tg lower than that of the p-phenylene sulfide
homopolymer. Therefore, this copolymer is advantage-
ous in that the stretching temperature can be lowered
and the processing can be conducted under conditions
substantially the sama as those employed in process-
ing polyethylene terephthalate ~PET~, etc.
Although the Tg of the block copolymer of the
present invention is lower than that of the homopoly-
mer, this copol~mer is characterized in that it is acrystalline polymer having a Tm close to the Tm
of the homopolymer probably because the
-1~
~ 27~53~
heat resistance of the polymer is gove~ned by the
-S-~ blocks. This is the most remarkable dif-
ference between the copolymer of the present invention
and an ordinary p-phenylene sulfide copolymer (i.e.,
random copolymer), since the T~ of the latter dis-
appears (i.e., the latter becomes amorphous) or it
is greatly reduced. Thus, the heat resistance of
the copolymer of the present invention can be main-
tained.
The difference between the upper limit Tc2 of
the crystallization temperature range (i.e., the
temperature at which the crystallization is initiated
as the temperature of the molten block copolymer is
lowered) of the block copolymer of the present inven-
tion and the Tm thereof is quite large, and the
crystallization rate is not very high, while Tc2 of
the p-phenylene sulfide homopolymer is very close to
the 'Tm thereof and the crystallization rate of this
homopolymer is quite high. These are important
characteristic features of the block copolymer of
the present invention. As described above, the block
copolymer of the present invention is suitable for
various processing processes since it can be amply
molded even in the supercooling temperature range,
i.e., the temperature range between Tm and Tc2, while
the homopolymer cannot be melt-processed easily in
the inflation, extrusion molding or melt spinning
18-
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~.~72S35
process, since the Tc2 thereof is very close to the
Tm thereof, and its crystallization rate is quite
high, whereby it is crystallized rapidly after the
melt spinning.
The block copolymer of the present invention
has a Tc2 in the range of ordinarily 150 to 230C.
The lower limit Tc1 of the crystallization temperature
range (i.e., the temperature at which the crystalli-
zation is initiated as the temperature of the amor-
phous block copolymer is elevated) o the block co-
polymer of the present invention is ordinarily in the
range of 100 to 150C.
The values of Tm, Tg, Tcl and Tc2 are values
represented by the melting peak, the temperature at
which the heat absorption is initiated, and the
cr~stallization peak, respectivelyl as measured by
using 10 mg of a sample by means o~ a differential
scanniny calorimeter ~DSC) of Shimadzu Seisaku-sho
at a temperature-elevation or -lowering rate of 10C/
2Q min in a nitrogen atmosphere. This sample is in
molten state to rapidly cooled, substantially
amorphous state.
The degree of crystallinity of the block co-
polymer of the present invention is ample Eor main-
tainlng the heat resistance due to the crystallization
of the polymer though it does not exceed the degree
of crystallinity of the p-phenylene sulide polymer.
--19--
t~
Therefore, high heat resistance of the copolymer can
be obtained by amply crystallizing the same accord-
ing to heat setting. Further, the heat resistance
can be improved by increasing the degree of crystal-
linity by carrying out stretch-orientation prior to
the heat setting. Ordinary random copolymers
have no crystallinity whatsoever or they have only a
slight crystallinity, and, therefore, the effect of
realizing heat resistance by heat setting cannot be
expected. They hav~ lost their property of heat
resistance.
The crystallization index (Ci) of the heat-
treated, but not stretch-oriented, block copolymer of
the present invention is in the range of 15 to 45.
The crystallization index Ci is a value obtained from
an X-ray diffraction pattern ~2~ = 17 -23) according
to the formula:
Ci = [Acj ~Ac ', Aa) ] x 100
wherein Ac represents crys~alline sca~tering in~ensity
and Aa represents amorphous scattering intensity L ref.:
J. Appl. Poly. Sci. 20, 2545 (1976)]. The value Ci is
determined in the present invention by melt-pressing
the block copolymer at a temperature higher than its
melting point by about 30C by means of a hot press,
rapidly cooling the same with water to obtain a
film having a thickness of 0.1 to 0.2 mm,
-20-
:
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33~
heat-treating the film at a temperature lower than
the melting point by 20C for 20 min. to effect the
crystalli~ation, and measuring the Ci of the thus
heat-treated film. The heat-treated film has an
increased Ci in the range of generally 40 to 90
after the stretch-orientation.
Since the homopolymer has an excessively high
crystallization rate, and, accordingly, coarse sphe--
rulites are formed, rapid crystallization and solidify~g
occur after the melt molding, whereby stretch
orientation thereof by ample expansion of the same
by the inflation method is difficult. It is quita
difficult to prepare a sm~oth, uniform sheet or film
by a T-die method, to obtain highly stretchable
filaments by a melt-spinning method, or to obtain
tough extrusion molded products or tough electric
wire coatings from the homopolymer for the same
reasons as described above.
On the other hand, when the block copolymer of
the present invention is used, it is possible to
obtain an amply expanded and stretch-oriented film or
sheet by the inflation method, since said block co-
polymer has a suitable crystallization rate, and,
therefore, the resulting spherulites are fine. Thus,
it becomes possible to prepare a smooth, uniform
sheet or film by a T-die method, to obtain tough
moldings by an extrusion method, to obtain highly
-21
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. .
, , :, ~ .:
:~7~535
stretchable filaments by a melt-spinning process and
to obtain a tough electric wire coating.
In this connection, it is very difficult to
obtain a practically valuable, heat set film
from a homopolymer having a melt viscosity n* of as
low as 2,000 P, since it is partially whitened due to
the coarse crystal formation in the heat setting.
On the other hand, a practically valuable, uniform,
heat set film can be obtained from the block
polymer of the present invention since coarse spheru-
lites are not easily formed. Because the formed
spherulites are not easily made coarse, not only films
but also other molded articles obtained from the
block copolymer of the present invention have greatly
advantageous physical properties, where~y they are
; not made brittle but keep their toughness e~en after
the heat setting carribd out for the purpose of
imparting the heat resistance.
Production of Block Copolymer
Summary
The block copolymer of the present invention
consists essentially of a block consisting essential-
ly of p-phenylene sulfide recurring units (A) and a
block consisting essentially of xecurring units ~B)
consisting essentially of m-phenylene sulfide. This
copolymer can be produced by any process capable of
forming both blocks and bonding them.
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;
~272S~i
20375-527
More specifically, in one mocle of the process,
one of the ~locks is formed, and the polymer chain
is then e~tended by polymerization thereover of the
monomer to form the other block whereby formation oE
the second block and bonding of the second block
with the first block take place simultaneously.
The process for producing the block copolymer of
the present invention is essentially the same as a
conventional process for producing a phenylene sulfide
polymer except that care is taken in the formation and
bonding of the blocks and the varieties of the pheny-
lene sulfide recurring uni-ts and that modifieations
are made if necessary in the former process. That is,
the process of the present invention for producing
the block polymer comprises heating an al]cali me~al
sulfide and a dihaloaromatie compound (compriSincJ
ma.inly p- and m-dihalobenzenes) in an aprotie polar
orc3anic solvent to accomplish condensation (-to remove
the alkali metal halide).
Starting materials
The alkali metal sulfides which are the sources of
the sulfide bond are preferably Na, Li, X and ~b sul-
fides. From the viewpoint of reactivity, Na and Lisulfides are particularly preferred. When they contai.n
water of crystallization, the water content thereof can
-23-
S35
be reduced suitably by distillation or drying prior
to the initiation of the polymerization reaction.
Preferred examples of the aprotic polar organic
solvents used as the reaction medium are carboxylic
acid amides, organic phosphoric acid amides, and
urea derivatives. Among these, N-methylpyrrolidone,
which is hereinbelow abbreviated as "NMP", hexatri-
methylphosphoric acid triamide and tetramethylurea
are particularly preferred from the viewpoints of
chemical and thermal stabilities.
Among the dihaloaromatic compounds, examples of
p-dihalobenzenes used for forming the p-phenylene
sulfide blocks are p-dichlorobenzene and p-dibromo-
benzene. Preferred examples of the dihalo-
substituted aromatic compounds usable in a smallamount together with the m~dihalobenzene to form the
other blocks include the following compounds, (but
they are not limited to these compounds):
X ~ -Y, ~ , X ~ ~ Y,
X ~ ~ -Y, X ~ -O- ~ -Y, and X- ~ - t~-Y
wherein X and Y each represent a halogen atom.
Further, polyfunctional compounds having 3 or
more halogen atoms such as 1,2,3- or 1,2,4-trihalo-
benzenes can also be usea.
-24-
:, .
~2~35
As a matter of course, the polymerization con-
ditions must be selected so as to obtain a polymer
having a n* of 50 to 100,000 P, preferably 1,000 to
50,000 P.
Production process (I)
Production process (I) comprises forming blocks
of the p-phenylene sulfide recurring units ~A), and
then forming recurring units consisting essentially
of m-phenylene sulfid2 in situ with simultaneous
bonding of it with the block (A).
When the starting alkali metal sulfide contains
water of crystallization, that is, when the starting
alkali metal sulfide is Na2S 9H2O, Na2S 5H2O or Na2S
3H2O (includiny a product of in situ reaction of
NaHS 2H2O + NaOH ~ Na25 3H2O), it is preferable to
reduce the water content thereof suitably by drying
before it i5 added to the.organic solvent, to add
the alkali metal sulfide alone to the organic solvent,
and then to heat the mi.xture to about 200C to distill
the water off or to chemically dehydrate the same by
addition of CaO, etc. so as to control the water
content suitably (ordinarily to 0.5 to 2.5 mol/mol of
the sulfide). Then, p-dihaloben~ene is added in such
an amount that the molar ratio thereof to the sulfide
will ordinarily be 0.95 to 1.05. The mixture is
heated to a suitable temperature, preferably 160 to
300C, particularly 190 to 260~C, to carry out the
-25-
1.~, . .
.~ , . . .
' I '
.. : , . . .
1~7~S3~
20375-527
polymerization reaction until an average polymer-
ization degree of the resulting p-phenylene sulfide
prepolymer of 20 to 5,000 is obtained to obtain
the reaction liquid mix,ture (C) containing the pre~olymer.
The required time is generally abou-t 0.5 to 30 hrs.
On the other hand, the starting alkali metal
sulfide is dried and then charged into the organic
solvent in the same manner as above, or, alternative-
ly, the water content of the alkali metal sulfide is
controlled by distillation in the organic solvent or
by a chemical dehydration, and then a m-dihalobenzene
(which can contain a small amoun-t of a dihalo-
substituted aromatic compound) is added thereto
usually in such an amount that the molar ratio there-
of to the sulfide would be 0.95/1 to 1.05/1 to obtain
an unreacted liquid mixture (D).
The unreacted liquid mixture (D) is mixed withthe reactiOn liquid mixture (C) contai.ning the prepolymer in
a given ratio (i.e., such'a ratio that the mol frac-
tion of the p-phenylene sulfide recurring units in the
resulting block copolymer will. be 0.50 to' 0.98). If
necessary, the water content of the mixture is control-
led again, and the mixture is hea-ted to a suitable
temperature, preferably 160 to 300C, particularly 200
~5 to 280C to carry out the polymerization reaction.
In this manner, the crystalline p-phenylene sulflde
bloc'c copolymer of the present invention is obtained.
-26-
3~ 3
~:UJ I
If necessary, the polymer is neutralized, filtered,
was~ed and dried to recover the same in the form of granules or a
powder.
The latter step in the production process tI) i~ carried
out for forming a block consisting essentially of units (B). An
indispensable matter to be introduced in this step i5 a dihaloaro-
matic compound consisting essentially of a m-dihalobenzene.
Therefore, the other starting material, i.e., the alkali metal
sulfide, and the organic solvent for the block formation can be
those used in the former step without necessitating fresh ones.
In this case, the amount(s) of the alkali metal sulfide and/or
organic solvent introduced in the former step is(are) increased,
if necessary. As a matter of course, this mode is possible also
in the following production process (II).
Production process (II)
The production process (II) is different from the
process (I) in that the blocks oE the recurring units (B) are
formed first. The process II is preferable to the process tI)
because the ~econd step in II can be carried out with more ease
than the second step in I since p-dihalobenzene polymerizes with
more ease than m-dihalobenzene.
. ~
27
,. ..
..
~,. ..
'51 ;~?d ~2
~ ~3~
Particularly for obtaining block copolymers having a
high molecular weight, the process (II) is the most effec-
tive among the three processes described above.
Generally, the following relationship is recognized;
n:m = X~ X~
.: m = n x (l - X)
X
wherein: n represents an average length (degree of
polymerization) of the block of p-phenylene sulfide
recurring units (A); X represents a mol fraction; and
m represents an average length of the block o~ recurr-
ing unit B consisting essentially of m-phenylene
sulfide.
Therefore, in a block polymer in which n is 20
to 5,000,and m of the recurrin~ unit (B) is in the
range of 20 x (1 X X) to 5,000 x (1 X X) with the
proviso that m is not less than 2. The production
process (II) has been developed on the basis of this
relationship.
In this process, the polar organic solvent and
the starting alkali metal sulfide having a controlled
water content are charged into a reactor in the same
manner as in process (I), the m-dihalobenzene (which
can contain a small amount of a dihalo-substituted
aromatic compound) is added thereto in such an amount
that the molar ratio thereof to the sulfide will be
0.95/1 to 1.05/1, and the mixture is heated to a
suitable temperature, particularly 160 to 300C,
-28-
..'
' ~
3~
~, UJ t J ~
preferably 190 to 260C, to carry out the polymerization reaction
until the average degree of polymerization of ~he resulting
arylene sulfide prepolymer reaches 20 x (lX X) to 5,000 x
~ . Thus, a reaction liquid mixture (E) containing
the prepolymer is obtained.
On the other hand, the polar organic solvent and the
starting alkali metal sulfide having a controlled water content
are charged into a reactor in the same manner as in the process
(I). A p-dihalobenzene is added thereto in such an amount that
lû the molar ratio thereof to the sulfide will be 0.95/1 to 1.05/1 to
obtain an unreacted liquid mixture ~F). As described above, the
essentially indispensable component of the mixture (F) is the
p-dihalobenzene, and this mixture can be free of the sulfide and
solvent.
The unreacted liquid mixture (F) is mixed with the
prepolymer-containing reaction liquid mi~ture (E) obtained as
above in a specific ratio. I necessary, the water content of the
resulting mixture is controlled again, and the mixture is heated
to a suitable temperature, particularly 160 to 300C, preferably
200 to 280C, to carry out the polymeriæation reaction. Thus, the
crystalline p-phenylene sulfide block copolymer o~ the present
invention is obtained. The polymer may be recovered and purified
in the same manner as in the process (I).
-29-
.
, ::
r
~L~ 7
20375-527
Uses of the Block CopolYmer
The block copolymer of the present invention is
usable for the production of various molded articles
prefe.rably in ~he form of at least a monoaxially
s-tretch-oriented product.
Fllms
The crystalline p-phenylene sulfide block co-
. polymer of the present invention can be shaped into
- films or sheets by an infl.ation method or l'-die metho~.
The films or sheets obtained by the T-die method can
be further stretched into oriented films by means of
a tenter, etc.
The block copolymer of the present invention can
- 30 -
: :; ~ :
.. ~; -
: -.
:. . . ,. - . . . :
::: . -:
: ~,: ~ .
.. ...
S35
20375-527
be shaped directly into a biaxially oriented film
by heating the same to a temperature of at least Tm
to melt the same and then expandin~ it to a 5 to 500
times as area ratio at a resin temperature in -the
S range oE Tc~ to 350C. The stretch-oriented film
can further be converte~ to a heat resistant, stretch-
oriented film having an increased degree of crystal-
lization by heat-treating (i.e., heat-setting) the same
a, a temperature in the range of Tcl to Tm while
the contraction or elongation is limited to up to 20%
or while the size is kept unchanged.
In the T-die film formation method, the block
copolymer of the present invention is melted by heat~
ing it to a temperature of at least Tml and the melt
is extruded through a T-die while the resin tempera-
ture is held above Tc2and below 350C, the extr~ion product
being cooled rapidly or gradually and wound to obtain
a non-orien~ed sheet or film. This sheet or film
can be stretched monoa~ially or biaxially to 2 to 20
times the initial area by means of a tenter or the like
at a temperature in the range of Tg and Tcl.
These non-oriented sheets or films or stretch~
oriented ~ilms can also be converted into a heat-
resistant film ~aving an increased de~ree of crystal-
lization by heat-setting the same at a temperat~lre in
the range of Tcl to Tm while the contraction or
elongation is limited to up to 20~ or while the size
- : ~: .
- .: .: . : .
:~
x~s
is kept unchanged.
The films or sheets thus obtained from the
crystalline p-phenylene sulfide block copolymer of
the present invention have a Tm of 250 to 285C, Tg
of 20 to 80C, Ci of 15 to 85, and thickness of 1 ~m
to 5 mm. The films heat set after the stretch
orientation has a Ci of 40 to 85 and thickness of 1
~m to 2 mm.
Filaments
Stretched filaments can be produced from the
crystalline p-phenylene sulfide block copolymer of
the present invention by heating it to a temperature
of Tm to 400C, extruding the obtained melt through
a nozzle, spinning the same at a resin temperature of
Tc2 to 350C, and stretchlng the extrusion product to
2 to 20-folds at a temperature in the range of Tcl to
Tm.
When the stretched filament is blended with
carbon fibers, glass fibers or aramide fibers and the
obtained blend is heated to a temperature higher than
its melting point, a stampable sheet can be obtained.
The stretched ilament can be converted into a heat-
resistant one having an increased degree of crystal
lization (Ci: 40 to 90) by heat-setting the same at
a temperature in the range o~ Tcl to Tm while th~
contraction or elongation is limited to up to 20%, or
while the size is kept unchanged.
-3~-
':
'~
~ .,: " . '
~.~7~5~S
Electric wire coating
Electric wires can be coated with the crystal-
line p~phenylene sulfide block copolymer of the
present invention or a composition comprising this
copolymer and an inorganic filler by heating the co-
polymer or the composition to a temperature in the
range of Tm to 400C to melt the same and then coat-
ing the wire with the melL extruded through a cross-
head die. When the stretch ratio in the first
stretching i5 controlled to 50 to 500-folds and the
tempexature in the subsequent heat treatment is con~
trolled in the range of Tcl to Tm to accomplish the
heat setting, a tough, heat-resistant coated
electric wire having a Ci of 15 to 70 can be obtained.
Extrusion-molded products
;Tough, heat-resistant extrusion molded articles
such as plates, pipes, rods and profiles having a Ci
of 15 to 60 can be obtained from the crystalline p-
phenylene sulfide block copolymer of the present
invention or from a composition comprising the copolymer
and a fibrous or powdery filler by heating the same
to a temperature in the range of Tm to 400C, extrud-
ing the obtained melt through a molding die, cooling
the extrusion product rapidly or gradually and heat-
treating the product at a temperature of Tcl to Tm.Injection-molded products
Tough, heat-resistant moldings can be obtained
-33-
: : .:. , : ::
,.. .
::--- ::: ,:: :
.: .~
~L~,7~5~S
from the crystalline p-phenylene sulfide block co-
polymer of the present invention or from a composi-
tion comprising the copolymer and a fibrous or powdery
filler by heating the same to a temperature in the
range of Tm to 400C, injecting the obtained melt
into a mold and heat setting the product at a
temperature in the range of Tcl to Tm. The block CG-
polymer of the present invention is suitable parti-
cularly for the production of large molded articles
and thick molded structures, since rough spherulites
which cause cracks ar~ not easily formed.
Compositions
The crystalline p-phenylene sulfide block co-
polymer of the present invention can also be melt-
mixed with a powdery inorganic filler such as mica,Tio2, SiO2~ A12O3, CaCO3, carbon black; talc, CaSiO3
or MgCO3 or with a fibrous filler such as glass,
carhon, graphite or aramide fi~er to form a composi-
tion. This copolymer can be blended also with, for
example, a poly-p-phenylene sulfide, poly m-phenylene
sulfide, polyphenylene sulfide random copolymer,
polyimide, polyamide, polyether ether ketone, poly-
sulfone, polyether sulfone, polyetherimide, polyarylene~
polyphenylene ether, polycarbonate, polyethylene
terephthalate, polybutylene terephthalate, polyacetal,
polypropylene,polyethylene, ABS r polyvinyl chloride,
polymethyl methacrylate, polystyrene, polyvinylidene
-34-
1~7~53~
20375-527
fluoride, polytetrafluoroethylene or tetrafluoro-
ethylene copolymer to form a composition.
The crystalline p-phenylene sulfide block co-
polymer of the present invention can be converted
S into a high molecular ion complex by reacting the same
with an alkali metal or alkaline earth metal hydroxide,
oxide or alkoxide (includin~ phenoxide) at a tem-
perature of 200 to 400C (reference: specification
o~ Japanese Patent Application No.95705/1984).
Secondar~ uses
The heat-resistant films and sheets obtained
from the crystalline p-phenylene sulfide block copoly-
mer of the present invention or a composition thereof
are useful as starting materials for printed circuit
lS boards, magnetic tapes (both coated type and vapor-
deposited type), insula-tin~ tapes and floppy discs :in
the electronic and electric technical fields. The
extrusion molded products (suçh as plates, pipes and
profiles) are useful as printed circuit boards and
protective tubes for wire assemblies in the electronic
and electric art and as anti-corrosive, heat-resistant
pipes and tubes in the technical ield of chemical
industry. Electric wires coated with these materials
are useful as heat-resistant, anticorrosive electric
wires. The injection-molded products are useful as
IC-sealin~ materials, printed circuit boards, con-
nectorS and parts for microwave machineries in the
-35-
,
. ~- . . .
'7~S35
20375-527
electronic and electric field and as large-sized
pumps, large-sized valves, sealing materials and
lining materials in the chemical industry.
Printedcircuit Boards
s One of the secondary uses of these films and
sheets is the use of the above-mentioned block co-
polymer as a resin component for printed-wiring boards.
Printed circuitboards according to the present
invention are as defined above.
Block copolymer
~he mol fraction of the recurring units ~ -S-~
in the ~ -S~ blocks in the molecular chain is in
the range of 0.50 to 0.98, preferably 0.60 to 0.90.
By controlling the mol fraction within this range,
the crystallinity can be maintained while the excel-
lent adhesion between the base and the metal is retain-
ed.
The block copolymer of the present invention
has a melt viscosity (n*) of 300 to 50,000 P, parti-
cularly preferably 300 to 30, ooo P, as determined at
310C at a shear rate of 200 sec 1. When the copolymer
has a melt viscosity of less than 300 P (i.e., a low
molecular weight), its strength is insufficient for
the production of the printed circuit boards. When
the melt viscosity exceeds 50,000 P, molding becomes
difficult. The block copolymer of the present inven-
tion has a crystalline melting point (Tm)
. .
... ..
,:~;' .. : ,
20375~527
in the range of 200 to 350C preferably 250 to 285C. When the
crystalline melting point is less than 200C, the heat resistance
is insufficient for printed circuit boards,and when it exceeds
350C, molding operation becomes difficult.
- The number of the recurring units ~ S-~-, i.e.,
the degree of polymeri~ation of the polyphenylene sulfide block
component, is determined according to a fluorescent X-ray method.
The mol fraction can be determined easily according to infrared
analysis. The crystallization temperature is a value represented
by a melting peak as determined by using 10 mg of the sample at a
rate of 10C/min. by means of a differential s~anning calori-
meter.
The base resin for the printed circuit boards according
to the present invention is a polymer comprising mainly the
phenylene sulide block copolymer. The term "comprising mainly"
herein indicates that the amount of the phenylene sulfide block
copolymer is predominant.
Fibrous reinforcing materials
The fibrous reinforcing materials used in the present
invention includes synthetic inorganic fibers ~such as glass
fibers, silica fibers, alumina fibers and ceramic fibers),
excluding electroconductive ones such as metals and carbonaceous
fibers; natural inorganic ibers (such as rock wool); synthetic
organic fibers (such as aromatic amide fibers, phenol fibers
..,:;: :: ~. - '
- -: :, .: .,
' ~ ,' ',: ~ " , :,
', i' '':
~ S3~
20375-5~7
and cellulose fibers); and natural organic fibers
(such as pulps and cotton). From the viewpoints of
electrical insulation properties, heat resistance,
strenyth and economy, synthetic inorganic fibers,
S particularly glass fibers, are preferred.
The fibrous reinforcing materials may be in the
form of any of short.fibers, long fibers, papers,
mats, felts and knits as long as they have an aspect
ratio (fiber length/fiber diameter) of at least lO.
In the production of the printed circuit boards by the
injection molding method, short fibers are parti-
cularly preferred, in general. When the extrusion
molding or compression molding method is employed, the
form of the fibers.is not limited. When the inorganic
fibers are used as fibrous reinforcing material and
an improvement of the wettability thereof with the
phenylene sulfide block copolymer ~base resin) is
desired, treatment of the surface with a silane coupl-
ing agent (such as epoxysilane or mercaptosi.lane) is
20 . effective. It is also possible to use commercially
available, surface-treated inorganic fibers.
The amount of the fibrous reinforcing material is
determined suitably so that the amounts of the pheny-
lene sulfide block copolymer and the fibrous reinforc-
ing material will be 50 - 95 vol. % and 5 - 50 vol. %,
respectively, based on the total volume thereof (their
volumes can be easily de-termined by actual measurement
-38-
.:
~Z7~3S
20375~527
or calculation based on the relationship between
wei~ht and specific gravity). When the amount of
the fibrous reinfoxcing material is less than the
above indica-ted value, adequate effect thereof can-
S not be obtained. On the other hand, when it exceedsthe indicated upper limit, the properties of the
phenylene sulfide block copolymer cannot be exhibit-
ed satisfactorily.
The phenylene sulfide block copolymer used as
the base resin according to the present invention may
contain, in addition to the fibrous reinforcing
material, a small amount of a filler (such as calcium
carbonate, titanium oxide, silica or alumina), anti-
oxidant, stabili~er, lubricant, crystallization
nucleatin~ agent, colorant, releasing agent and other
resins provided their effects are not counter to the
objects of the invention.
Metal layer
~or the metal layer to be formed on the printed
circuit board of the present invention, a thin layer
of copper, aluminum, silver, gold layer or the like
can be used. Of these, a copper or aluminum layer is
representative.
Preparation of Printed Circuit Board
. _
Moldinq of Base Material
_
The process for molding the composite of the
phenylene sulfide block copolymer and the fibrous
39-
. . :. : .. -.
.. , ~ : .
- -' '" ' ~,
'' '
~ 7~
20375-5~7
reinforcing material of the present invention into
the plates is not particularly limited.
In the injection molding process, the plates
can be molded by injecting a blend of the phenylene
sulfide block copolymer~ and the fibrous reinforcing
material into a mold by means of an injection mold-
ing machine. When a specially designed mold is used,
moldings havlng through holes can be prepared direct-
ly. This process is advantageous in that a subsequent
hole-forming step is unnecessary. When a metal foil
having a punched pattern is inserted, the printed-
circuit board can be obtained directly. By this
process the number of steps in the production of the
printed circuit board can be reduced remarkably.
In one mode of production of a plate by extru-
sion molding process, a blend or laminate comprising
the fibrous rein~orciny material and the phenylene
sulfide block copolymer is in~roduced between a pair
of metal belts to carry out continuous compression,
heating, and melting. If a metal foil is placed on
one or both surfaces thexeof, plate having a metal
layer can be obtained directly.
In one mode of production of a plate by the
compression molding process, a blend or laminate com-
prising the phenylene sulfide block copolymer and thefibrous reinforcing material is charged into a mold
and subjected to compression, heating and melting to
--~0--
.: :..
": ' ' ' " :
': ~' ': ,
. -
'' ' .
5~S
20375-527
obtain the plate. If a metal foil is placed on one
or both surfaces thereof, a plate having metal layer(s)
can be obtained directly also in this case.
Production of printed circuit boards
In the production of printed circui.t boards by
forming a metal layer of a circuit pattern on an insu-
lating board obtained by molding a composite of the
phenylene sulfide block copolymer of the present
inv~ntion and the fibrous reinforcing material, the
production process is not particularly limited.
For example, a so-called subtractive method
which comprises bonding a metal foil to a board (this
operation may be omitted when the metal foil is applied
in the course of the preparation oS the board), and
removing unnecessary parts of the metal foil by e-tch-
ing -to form a circuit pa-ttern can be used. When a
board having no metal foil layer, particularly a
board obta.ined by the injection molding method, is
used, a so-called additive method wherein a circuit
~0 pattern is formed by a metal plating in necessary parts
on the board or a so-called s-tamping foil method where-
in a metal ~oil having a previously stamped pattern
is applied thereto can be adopted.
The bonding of the metal foil to the board com-
prising a composite of the phenylene sulfide block co-
polymer of the present invention and the fibrous re-
inforcing material can also be accomplished by means of
41~
~. .
3L~'7~53~
an adhesive (such as nitrile rubber, epoxy or urethane
adhesive) after the production of the board by molding.
In another process, the metal foil is bonded to the
board by melt-contact-bonding in the course of the
molding of the board or after the molding without
using any adhesive.
Further, the cixcuit pattern can also be formed
directly by metal plating. When a plating process is
employed, the sur~ace of the board is pretreated b~ a
physical or chemical method such as mechanical abra-
sion or treatment with an organic solvent (such as a
carboxylic acid amide, etherf ketone, ester, aromatic
hydrocarbon, halogenated hydrocarbon, urea derivative
or sulfolane), an oxidizing agent (such as chromic acid,
permanganic acid or nitric acid), or a solution of a
Lewis acid (such as AlC13, TiB~, SbF5, SnC14 or BF3)
so as to make the surface rough. By this treatment,
the adhesion between the metal layer and the insulat-
ing board can be increased. This effect is further
improved by incorporating a fine powder of calcium
carbonate or titanium oxide in the s-~arting materials
for the boardO The adhesion between the metal and
the board comprising the phenylene sulfide copolymer
base resin of the present invention can be impxoved by
this pretreatment since the surface of the board is
roughened suitably because of the characteristic pro-
perties of the block copolymer, while such an adhesion-
-42-
~;~7~:S;3~
improving effect cannot be obtained by the same pre~
treatment in a board comprising an ordinary poly-p-
phenylene sulfide base resin. This is one of the
important characteristic features of the insulating
base.
Sealing or Encapsulation Compositions
Another secondary use of the block copolymer is
the use thereof as a sealing or encapsulation com-
position comprising this block copolymer as a resin
component.
The sealing composition of the present invention
and the sealing process with the use thereof are as
follows.
Block copolymers
The presence of the blocks comprising ~ S-~
assures the crystallinity of the copolymer and heat
resistance thereof owing to the crystallinity. The
presence of the recurring units ~ S-~ causes (1
a lowering of the melt viscosity o e copolymer to
remarkably improve the injection moldability thereof,
(2) prevention of the formation of spherulites to
prevent crack formation or cutting or deformation of
bonding wires, and (3) improvement of the adhesion to
the lead frame or the bonding wire to greatly improve
high-temperature moisture resistance of particularly
the sealed electronic parts. Thus, by the introduction
oE the recurring units ~ S~ , the defects of the
-43-
7~5~
20375-527
p-phenylene sul~ide homopolymer can be overcome.
The average degree of polymerization of the
S-~ blocks in the block copolymer of the pre-
sent invention is in the range of 20 to 2,000, pre-
S ferably 40 to 1,000. With an average degree of
polymerization less than 20, the crystallinity of the
polymer is insuf~icient, and the molded articles
obtained therefrom would have insuf~icient heat resist-
ance. When the average degree of polymerization
exceeds 2,000, the molecular weight of the copolymer
is excessive, and properties thereof are like those
of the p-phenylene sulfide homopo~ymer. ~s a result,
molded articles having cracks, broken bonding wire,
or poor high-temperature moisture resistance are un-
favorably formed.
The melt viscosity, which is an index of the
molecular weight, of the phenylene sulfide block co-
polymer of the present invention is suitably in the
range of 10 to 1,500 P (at 310~ and a shèar rate of
200 sec 1), particularly 50 to 800 P. When the melt
viscosity is less than 10 P, the molecular weight is
too low to obtain molded articles oE a high strength.
When it is as high as higher than 1,500 P, bonding
wire is broken in the injection molding step or an
insufficient filling is unfavorably caused.
The sealing composition of the present invention
may contain, in addition to the phenylene sulfide
-4~-
~ ~-
7~
block copolymer ~main resin component), a small amount
of other thermoplastic resins (such as poly-m-phenylene
sulfide, poly-p-phenylene sulfide, m-phenylene sulfide/
p-phenylene sulfide random copolymer, polybutyrene
terephthalate, polyethylene terephthalate, polyether
sulfone and polyamide) and thermosetting resins (such
as epoxy resin, silicone resin and urethane resin)
provided that the characteristic features of the com-
position are not impaired. The amount of the main
resin component, i.e., phenylene sulfide block copolymer,
is at least 60 wt. ~ based on the total resin. A pre-
ferred minor resin component is poly-m-phenylene sulfide
or poly-p-phenylene sulfide.
Fillers
The inorganic fillers which can be contained in
the sealing composit;on of the present invention
include fibrous ~illers, non-fibrous fillers, and com-
binations thereof.
Examples of non-fibrous fillers are quartz powder,
glass powder, glass beads, alumina powder, TiO2 powder,
iron oxide powder, talc, clay and mica. The particle
size of these fillers is preferably up to 0.5 mm since
larger particles unfavorably cause the breaking of
bonding wires.
Examples of fibrous fillers are glass fibers,
silica fibers, wollastonite, potassium titanate fibers,
processed mineral fibers and ceramic fibers. Thos
-45-
~ ~ .
':
7~:;3~
having a fiber length of up to 0.5 mm and an aspect
ratio of at least 5 are preferred. Fibers longer
than 0.5 mm cause breakage of bonding wire, and
those having an aspect ratio of less than 5 un-
favorably have insufficient reinforcing effect.
When an inorganic filler is mixed into the
sealing composition of the present invention, the
amount thereof is preferably 20 to 300 wt.~, parti-
cularly 50 to 200 wt. ~. With more than 300 wt. ~,
the melt viscosity of the composition becomes exces-
sive, and breakage of bonding wire is caused. A con-
tent less than 20% of the inorganic filler is undesir-
able because the thermal expansion coefficient becomes
high to cause breakage of bonding wi.re.
In the case where an inorganic filler is mixed
into the sealing composition of the present invention,
the inorganic filler can be made hydrophobic by treat-
ing the same with a surface-treating agent such as a
silane coupling agent or titanate coupling agent so as
to improve the adhesion of the filler with the resin
or to reduce its hygroscopicity. Alternatively, these
treating agents can also be mixed into the sealing
composition. Further, a water-repellent such as a
modified silicone oil, fluorine oil or paraffin can
be mixed into the sealing composition so as to increase
the moistureproofness of the composition. Further,
assistants such as a lubricant, colorant, releasing
46-
.. ~. .
agent, heat stabilizer and curing agent may be added
into the sealing composition of the present invention
provided that they are not counter to the objects of
the invention.
Sealing or Encapsulation of Electronic Parts
After mixing the synthetic resin component, in-
organic filler and, if necessary, other additives, the
resulting composition is used for sealing electronic
parts.
The sealing may be conducted by a known process
such as injection molding or transfer molding process.
The molding is conducted with an ordinary injection-
molding machine or transfer-molding machine under the
conditions of a molding pressur~ of 10 to 200 kg/cm2,
cylinder temperature of 280 to 370C and mold tempera-
ture of 80 to 220C.
A characteristic feature of the present inven-
tion,which is that the resin componenk is a block co-
polymer having improved crysta~inity, can be exhibited
most effectively when the sealing is carried out by
injection molding of the resin composition.
EXPERIMENTAL EXAMPLES
.
Copolymers and Production Thereof
Synthesis Example A-l
.
11.0 kg of NMP ~N-methylpyrroli~one) and 20.0 mol
of Na2S ~H2O were placed in a 20-liter polymerization
pressure vessel. The mixture was heated to about 200C
-~7-
:.: .
7~ r
to distill off water. (The loss of S due to the dis-
charge in the form of H2S was 1.4 molar % based on
charged Na29, and the amount of water remaining in
the vessel was 27 mol.) Then 20.1 mol of p-DCB IP_
dichlorobenzene~ and 3.1 kg of NMP were added ~hereto.
After replacement of air with N2, polymerization
reaction was carried out at 210C for 4 hours. 53 mol
of water was added to the mixture, and the reaction
was continued at 2509C for 0.5 hour to obtain a li~uid
reaction mixture (C~ hich was taken out and stored.
A small amol-nt of ~he mixture (C-l) was sampled to
determine the degree of polymerization of the result-
ing p-phenylene sulfide prepolymer by fluorescent X-
ray method. The degree of polymerization was 320.
11.0 kg of NMP and 20.0 mol of Na2S 5H2O were
charged in a 20-liter polymerization pressure vessel.
The mixture was heated to about 200C to distill of water
~loss of S: 1.5 molar %, amount of water remaining in the
vessel: 29 mol). Then, 20.1 mol of m-DCB (m-dichloro-
benzene) and 3.0 kg of NMP were added thereto. The
mixture was cooled under stirring to obtain an un-
reacted liquid mixture ~D-l), which was taken out and
stored.
The liquid reaction mixture (C-l), unreacted
liquid mix~ure (D-l), and water were placed în a 1-
- liter polymerization pressure vessel in proportions
of 375 g/88 g/4.6 g, 328 g~l31.5 g/6.9 g, and 234 g/
-48-
: " ~- ' '
: :,
5~S
219 g/11.5 g and they were reacted at 250C for 20
hours. After completion of the reactions, the res
pective liquid reaction mixtures were filtered,
washed with hot water, and dried under reduced pres-
sure to obtain block copolymers (1-1), (1-2), and
~1-33-
Each block copolymer thus obtained was melted
at a temperature higher than its melting point by
about 30C and pressed with a hot press. The block
copolymer was cooled rapidly with water to obtain a
film having a thickness of 0.1 to 0.2m~. The copolymer
composition of this sample was determined according
to an infrared analysis (FT-IR method). Tg, Tm, Tc
and Tc2 of this sample were also measured.
Each film was heat-treated at a temperature lower
than its melting point by 20C for 20 min. to o~tain
a heat-treated, crystallized sheet. The crystalliza-
tion index Ci of the sheet was measured b~ X-ray di~
fraction method.
The results are æummarized in Table A-l.
S~nthesis Example_A-2
lloO Kg of NMP and 20.0 mol of Na2S 5H2O were
placed in a 20-liter polymerization pressuxe vessel.
The mixture was heated to about 200C to distill off water
(loss of S: 1.5 molar ~, and amount of water remaining in
the vessel: 28 mol~. Thent 20.1 mol of m-DCB and 3~0
kg of NMP were added thereto. ~fter replacement of
, -4g-
S~5
air with N2, the polymerization reaction was carried
out at 210C for 8 hours. 52 mol of water was added
to the mixture and the reaction was continued at 250C
for 0.5 hour to obtain a liquid reaction mixture (E-
5 2), which was taken out and stored.
A small amount of the liquid (E-2) was sampled
to determine the degree of polymerization of the
resulting m-phenylene sulfide prepolymer by the GPC
method. The degree of polymerization was 60.
11.0 kg of NMP and 20.0 mol of Na2S 5H2O were
placed in a 20-liter polymerization pressure vessel.
The mixture was heated to about 200C to distill off
water (loss of S: 15 molar %, amount of water remaining in
the vessel: 26 mol). Then, 20.2 mol of p-PCB and 3.0 kg
of NMP were added thereto. The mixture was cooled under
stirring to obtain an unreacted liquid mixture (F-2),
which was taken out and stored.
The liquid reaction mixture (E-2), unreacted
liquid mixture (F-2) and water were placed in a 1-
liter polymerization pressure vessel in proportionsof 97 gJ350 g/I9.4 g, 140.5 g/306 g/17 g and 234 g~
218.5 g/12.2 g and wera reacted at 250C for 20 hours.
After completion of the reactions, the respective
li~uid reaction mixtures were filtered, washed with
hot water and dried under reduced pressure to obtain
block copolymers (2-1), (2-2) and (2-33.
The mol fractions (X) of the recurring units
-50~
1~7;~S;~5ii
G ~ J--J ~. ~
-~- ~ ~ S-~- in the blocks were determined by infrared analysis
and found to be 0.86, 0.79, and 0.68, respectively. The degree of
polymerization of ~ S ) was calculated from the value of
X according to the formula: 60 x X . The results are
1 - X
shown in Table A-l together with the physical properties.
_ynthesis Example A-3
A liquid reaction mixture (C-3) containing p-phenylene
sulfide prepolymer was produced as in Synthesis Example A-l except
that the polymerization was carried at 210~C for 3 hours in a
20-liter polymerization pressure vessel. Further, an unreacted
liquid mixture (D-3) containing m-DCB was produced in the same
manner as in Synthesis Example A-1 in a 20-liter polymerization
pressure vessel.
7,170 g of the liquid ~C-3), 1,190 g oE the liquid (D-3)
- : :
'., ::.
.
. :,. ,,.,,, ,.... ~:
~;~'7~ 5
20375-527
and 60 g of water were placed in a 10-liter polymeri~ation pressure
vessel, and reaction thereof was carried out at 255C for 15 hours.
After completion of the reaction, a block polymer was recovered
from the reac-tion liquid in the same manner as in Synthesis Example
A-l. The polymerization was carried out in the same manner as
above in 4 batches. The polymers obtained in total of 5 batches
were blended together homogeneously and then shaped into polymer
pellets (3-]) with a pelletizer. The p-phenylene sulfide prepolymer
had an average degree of polymerization of 260.
A reaction liquid mixture (E-3) containing m-phenylene
sulfide prepolymer was obtained as in Synthesis Example 2 except
that the polymerization reaction was carried out at 210C ~or 6
hours in a 20-liter polymerization pressure vessel. An unreacted
liquid mixture (F-3) containing p-DCB was obtained in the same
manner as in Synthesis Example A-2 in a 20-liter polymerization
pressure vessel.
7,170 ~ of the liquid ~C-4), 1190 g of the liquid ~D~l)
and 60 g of water were placed in a 10-liter polymerization pressure
vessel, and reaction was carried out at 255~ for 15 hours. After
completion of the reaction, a block copolymer was recovered from
the reaction liquid in the same manner as in Synthesis Example A-l.
The polymerization was repeated in 5
- 52 -
.
. ", . . ~ ,
~Z7~
20375-527
batches in the same manner as above. The polymers
obtained in the total of 6 batches were blended toge-
ther homogeneously and then shaped into polymer pellets
(3-2) with a pelletizer. The m--phenylene sulfide pre-
polymer had an average degree of polymerization of 50.
Comparative Synthesis E~ample A-l
500 g of N~P and 1.00 mol of Na2S 3H2O were placed
in a l-liter polymerization pressure vessel. The mix-
ture was heated to about 200C to distill off water (loss
of S: 1.6 molar %, amount of water remaining in the vessel:
1.4 mol). Then, 0.867 mol of p-DCB, 0.153 mol of m-DCB
and 150 g of NMP were added thereto. Af-ter replacement
of air with N2, polymerization reaction was carried
out at 210C for 5 hours. 2.6 mol O;e water was added,
and the polymerization reaction was con-tinued at 250C
for 20 hours. After completion of the reaction, a
random copolymer (comp. l) was recovered from the
reaction liquid in the same manner as in Synthesis
Example 1. The properties oE the resulting random co-
polymer were examined in the same manner as in Synthesis
Example A-l to o~tain the results shown in l~able A-l.
Comparative Synthesis Example A-2
625 g of NMP and 1.00 mol of Na2S 3H2O were placed
in a 1-liter polymerization pressure vessel. The mix-
ture was heated to about 200C to distill off water (loss
of S: 1.5 molar %, amount of water remaining in the vessel:
1.4 mol). Then, 1.01 mol of p-DCB and 155 g of NMP were
-53-
3~.~7 .~
20375 S27
added thereto. After replacement of air with N2, polymerization
reaction was carried out at 200C for 2.5 hours. After completion
of -the reaction, the resulting reaction liquid mixture (C-Comp. 1)
was taken out and stored. The resulting p~phenylene sulfide
prepolymer had a degree of polymerization of up to 5.
400 g of the reaction liquid mixture (C-Comp. 1)/ 66 g of the
unreacted liquid mixture (D-l) obtained in Synthesis Example A-l
and 3.5 g of water were placed in a l-liter polymerization pressure
vessel. The reaction was carried out at 250C for 20 hours.
After completion oE the reaction, a block polymer (Comp. 2) was
recovered from the reaction liquid in the same manner as in
Synthesis Example A-l. The properties of this product were examined
in the same manner as above to obtain the results shown in Table
A-l.
Comparative Synthesis Example A-3
11.0 kg of NMP and 20.0 mol o Na2S~5H20 were placed in a
20-liter polymerization pressure vessel. The mixture was heated
to about 200C to distill off water ~loss of S: 1.4 molar ~,
amoun~ of water remainin~ in the vessel: 2~ mol). Then, 20.1 mol
of p-DCB and 3.1 kg of NMP were added thereto. After replacement
of air with N2, polymerization reaction was carried out at 210C
for 5 hours. 52 mol of water was added thereto,
t` ~
~ -54-
"
.. ..
'~
~.~7~3S
~:U ~ / J--.J ~. I
and the polymerization reaction was continued at 250C for 10
hours. After completion of the reaction, a p-phenylene sulfide
homopolymer was recovered from the reaction liquid in the same
manner as in Synthesis Example A-l. The polymerization was
carried out in the same manner as above in 3 batches. The
polymers obtained in the total of 4 batches were blended together
and then shaped into polymer pelle-ts (Comp. 3) with a pelletizerO
The properties of the thus obtained homopolymer were examined in
the same manner as in Synthesis Example A-l to obtain the results
lû shown in Table A-l.
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20375-527
Molding Example A-l
The polymer pellets (3-1), (3-2) and (Comp. 3)
obtained in Synthesis Example A-3 and Synthesis Com-
parative Example ~-3 were melted by heating to a
temperature above their melting points in a
35 mm ~ extruder provided with a circle die (dia~
meter of opening: 30 mm, clearance: 1 mm). The
molten resins were supercooled to 220 to 250C in
the die and airing part and expanded by stretching
6 -8-folds in the machi.ne directions to form inflated
films. The average thicknesses o-E the biaxially
oriented ~ilms obtained from the polymer pellets (3-1),
~3~2), and (Comp. 3) were 20, 20, and 45 ~m, respec-
tively.
The inflated films were heat-treated at 260C for
10 minutes while the sizes thereof were kept constant.
The films obtained from the polymers (3-1) and ~3-2)
could be heat-set uniformly and were biaxially
oriented films havin~ a high transparency, high
degree of crystallization and smooth surface. On the
other hand, the film obtained from the poIymer (Comp. 3)
was opaque and had a wavy surface, since whitening and
wrinkling were caused in the course of the heat treat--
ment. This phenomenon of the polymer (Comp. 3) was
considered to be due to a rapid crystallization which
occurred in the inflation step, and which inhibited
ample expansion and orientation. The heat set
-58-
:
:' ~
3~
20375-527
films obtained from the polymers (~-1) and (3-2)
had crystallization indexes of 68 and 65, res-
pectively.
A part of the pellets obtained from each of
the polymers (3-1), (3-2) and (Comp. 3) was hot-
pressed at 310C and rapidly cooled to form an amor-
phous film having a thickness of about 0.2 mm. It
was then stretched 3.0 x 3.0 fold by a biaxial
stretching machine of T. M. Long Co. at 87C, 87C
and 103C to obtain stretched films. This film
was heat-treated at 260C for 10 minutes to obtain
a heat-set film having a high transparency. These
heat-set films had thicknesses of 10, 8, and 9 ~m,
respectively, Ci of 75, 73, and 80, respectively,
crystal sizes ~determined from the diffraction peaks
(2,0,0) obtained by the X-ray diffraction method
according to a Schelle's formula] of 71, 78, and 75
A, respectively, and coefficients of heat contraction
of 12, 17 r and 13%, respectively.
Molding Example A-2
Non-stretched monofilaments were produced from
the pellets of each of the polymers (3-1), (3-23 and
(Comp. 3) by winding at a rate of 4 m/min. at 320C on the
average (take-off ratio Rl = 10) through a noz~le having
a diameter of 1 mm and a length of 5 mm by using a melt
tensiontester. The non-stretched monofilaments were
-59-
' '; '
535
20375-527
immersed in an oil bath at 85C, 85C, and 95C and
stretched with a jig to examine their stretchabili-
ties. The non-stretched filaments obtained ~rom the
polymers (3-1) and (3-2) had a break rate of less
than 10 % even after stretching 8-fold, while those
o~tained from the polymer (Comp. 3) had a break rate
of higher than 90% after stretching 8-fold probably
because crystallization had proceeded in the spinning
step. The average tensile moduli of elasticity and
average elongations of the fibers which were not
broken by the 8-fold stretching (30 to 90 ~m) were
530, 500 and 590 (kg/mm2), respec-tively, and lO0,
120 and 60%, respectively.
These fibers were heat-treated at 230C ~or 1
se¢ond to ac_omplish heat setting, while the elon-
gation was limited to 3%. The average tensile moduli
of elasticity and average elongations of khe heat-
set filaments were 800, 7~0, and 960 kg/mm2,
respectively, and 33, 35, and 18%, respectively.
Molding Example A-3
Copper wires having a diameter of 1 mm were melt-
coated with pelle-ts obtained from the polymer (3-1)
and (Comp. 3) by means of a small-sized extruder (l9
~l~ provided with an electric wire-coating die tip.
The extruder head temperature was 310C, and the die
tip temperature was 270C. In the melt-coating step,
the polymer was stretched to a primary stretching ratio
-60-
- - . . : ,
. . .
2 S3 ~
20375-5~7
of 140 to 160, i~nersed in a glycerol bath (140 to
160C) and then in an infrared heating bath to heat-
treat the same until the surface temperature of the
coated wires reached about 160 to 180C. Thus, the
crystallization was accomplished. Ci were 31 and
41, respectively. The enameled wire-type coated
wires thus obtained were subjected to an adhesion
test (9.2. torsion test) and dielectric breakdown
voltage resistance test (11.1.2. single stxand
method) according to JIS C 3003 (test methods for
enameled copper wires and enameled aluminum wires).
The results were as fo1lows:
average coating film thickness: 35 and 40 ~m
adhesion test: 100 - 120 times and 80 - 90 times
dielectric breakdown voltage resistance:
~20 (KV/0.1 mm) and ~ 15 (KV/0.1 mm)~
Molding Example ~-4
The polymer (3-2) was melted by heating in a
lg mm(~extruder provided with a die ha~ing a xinc~-
shaped opening of a diameter of 10 mm and a clearance
of 1 mm. The molten resin was supercooled to 220 to
250C in the die and the opening and extruded into
the form of a tube, which was cooled in a water shower
and cut. The obtained tube pieces were heat treated
at 130C for 1 hour, at 150C for 1 houx and at 220C
for 10 hours to bring about crystalli~ation. The heat-
treated tubes had a Ci of 2~.
-61-
.:.: `i; ' :
.: , -
.. ... ~ , . . . ..
,
127ZS;3 5
~.v.~, ~--,~,
Molding Example A-5
The polymer ~3-2), glass fiber (length: 2 cm, strands)
and mica were melt-mixed in a 19 ~m~ extruder to Eorm pellets
containing 50 wt. ~ of the glass fibers and 10 wt.% of mica. The
p~llets were injection~molded in an injection-molding machine
provided with a mold measuring 1.5 mm x 8 cm x 10 cm at 320C to
obtain a plate having a thickness of 1.5 mm. The plate was heat-
treated at 250C for 4 hours. Ci was 30. The non-heat-treated
plate thus obtained was interposed between sheets of copper foil
(of a thickness of 35 ~m) which had been surface-treated with a
zinc/copper alloy. After pressing with a hot press at 320C for
10 minutes, a copper-coated plate was obtained. This product was
heat-treated at 260C for 10 minutes. Ci was 26. The peeling
strength of the copper foil was 1.9 kg/cm.
-62-
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_rinted Circuit Boards
Synthesis_Example B
(1) 10 kg of N-methylpyrrolidone and 20.0 mol of
Na2S 5H2O were placed in a 20-liter polymerization pressure
vessel. The mixture was heated to about 200C to distill off
water (loss of S: 1.4 molar %, amount of water in the vessel: 30
mol). Then, 20 mol of p-dichlorobenzene and 4 kg of N-methylpyr-
rolidone were added thereto. Polymerization reaction was carried
out at 210C for 5 hours to obtain a reaction liquid mixture (~),
which was taken out and stored.
Separately, 10 kg of N-methylpyrrolidone and 20.0 mol of
Na2S 5H20 were placed in a 20-litex polymerization pressuxe
vessel. The mixture was heate~ to a~out 200C to distill off
water (loss of S: 1.4 molar %~ amount of wa-ter present in the
vessel: 28 mol). Then, 20.1 mol of m-dichlorobenzene and 4 kg of
~-methylpyrrolidone were added thereto, and the mixtuxe was
stirred uniformly to obtain an unreacted liquid mixture (B), which
was taken out and stored.
A small amount of the reaction liquid mixture A was
sampled to determine the degree of polymerization of the
resulting
-63-
~7~535
20375-S27
p-phenylene sulfide prepolymer by the fluorescent X-ray method and
GPC method. The degree of polymerization was 290.
13,280 g of the reaction liquid mixture A, 2,720 g of the
unreacted liquid mixture B, 8 g of 1,3,5-trichlorobenzene and 800 g
of water were charged in a 20-liter polymeriæation pressure vessel
and were reacted at 250C for 19 hours to obtain a polymer. The
polymerization was repeated in the same manner as above in 5 batches.
The polymers obtained in the total of 6 batches were blended to-
gether homogeneously to obtain a polymer A. The polymer A had a
melt viscosity of 2,600 P as determined at 310C at a shear rate of
200 sec 1, degree of polymerization of the ~ S-~ block of
290, mol fraction of ~ -S-t units of 0.86, and crystal melting
point of 280C.
(2) Reaction liquid mixtures tA~ and unreacted liquid
mixture (B) were prepared in the same manner as above. 12,000 q
of the liquid (A), 4,000 g of the liquid (B), 8 g of 1,2,9-trichloro-
benzene and 400 g of water were charged into a 20-liter polymeriz-
ation pressure vessel. The reaction was carried out at 25SC Eor
15 hours to obtain a polymer. Polymeri.zation was repeated in the
same manner as above in 5 batches. The polymers obtained as
described above were blended together homogeneously to obtain a
polymer B. The polymer B had a melt viscosity of 2,100
.. .. .
. .
: . .:
t7~3S
~; UJ / J ~
P, degree of polymerization of the -~- ~ S-~- block of 290,
mol fraction of ~ S-t- units oE 0.79 and crystal melting
point of 275C.
(3) A p-phenylene sulfide homopolymer to be used in a
comparative example was produced by a process disclosed in the
specification of Japanese Patent Application No. 164,691/1983. In
this process, 15 liter of N-methylpyrrOlidOne, 7.0 mol of water
and 30 g-equivalent of p-dichlorobenzene were charged into a 20-
liter pressure autoclave. Then, an anhydrous glass-state ion
complex (S~-/Na+/Mg2~/OH~ = 1/1/2/2) was added thereto in an
amount of 30.0 g-equivalent in terms of S2- in the ion complex.
After replacement of air with N2, the mixture was stirred at about
100C for 1 hour to obtain a homogeneous dispersion. Then, poly-
merization reaction was carried out at 205C for 32 hours. The
solvent was removed, and the polymer was washed in the ordinary
manner to obtain a p-phenylene sulfide homopolymer. The polymer-
ization was repeated in the same manner as above in 5 batches.
The polymers thus obtained were blended together homogeneously to
obtain a polymer X. The polymer X had a melt viscosity of 2,300 P
and crystal melting point of 286C.
Example B-1
The polymer A finely divided in a jet pulverizer was
applied uniformly on a glass chopped strand mat (MC ~50 A-010 of
Nittobo Co., Japan; untreated). The mat was formed into a lamin-
ate comprising 4 mat layers.
-65-
, ~ ~ , ...
,
20375-527
A copper foil (thickness: 35 ~) the surface of which
had been treated wi-th a zinc/copper alloy was placed
thereon. The laminate was passed between endless
metal belts and heated to 320 to 330C under pres-
sure in a heating zone. Then the thus treated
laminate was cooled and taken off at about 120C to
obtain a plate having a thickness of 1.6 mm and a
glass fiber content of 45 vol.%. A part of the pro~uct
Wa5 cut off and treated by an ordinary subtractive
method to obtain a printed circuit board (lA).
Example B-2
The polymer A or X finely divided in a jet pulver-
izer was blended with a silane-treated glass chop
strand having a fiber length of 6 mm ~CS 6 PE-~01; a
product of Nittobo Co., L-td.) and titanium o~ide
powder having a particle diameter of 0.~ ~rn (Tlpa~ue
R~820; a product of Ishihara Sangyo Co., ~td., ~apan)
in such amounts that a glass content of 30 vol. %
would be obtained. The biend was fed into a flat
plate mold, pressed at 325C under 2 kg/cm2 and cooled
rapidly to obtain a plate having a thickness of about
1.6 mm. ~ copper foil surface-treated with a zinc/
copper alloy was applied to the top and bottom inner
surfaces of the mold, and the plate was interposed
between the sheets o~ a foil and was pressed at 325C
under 8 kg/cm2 and then at 180C under ~0 kg/cm to
obtain a copper-coated plate. A part of the product
-66-
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: : :
. . .
..
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20375-527
was cut off and treated by an ordinary substractive
method to obtain a printed circuitboard 2A or 2X.
Example B-3
Three sheets of glass rovinc3 cloth cut into the
same size (WR 570 C-lO0 of Nittobo Co., Ltd., ~apan;
treated with a silane) were fed into a flat plate
mold. A mixture of the polymer B with the polymer X
in a ratio of 3:1 was finely pulverized in a jet pulver-
izer and placed uniformly between the sheets and
between the sheets and the mold. The laminate was
pressed at 325C under 4 kg/cm2 and cooled with
water to obtain a plate having a thickness of 1.6 mm
and a glass fiber content of 42 vol. %. Two sheets of
a copper foil (35 ~) which had been surface-treated
with a zinc/copper alloy punched in a circuit pattern
were applied to the top and bottom inner surEaces o~
the mold, and the plate obtained as described above
was interposed between the fo.~ls. After stamping at
320C under 8 kg/cm followed b~ pressing at 180C
under 40 kg/cm2 for 30 minutes, a printed circui-t board
3BX was obtained.
Example B-4
Each of the polymer ~ and X, finely pulverized
with a jet pulverizer was blended with glass chop
strands havin~ a length of 6 mm (CS 6 PE-401; a
produçt of Nittobo Co., Ltd., ~apan) and calcium
carbonate having a par-ticle diameter of 0.5 ~ (Super
~~7-
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S3~
20375-527
Flex of P~izer Kyzley Co., Ltd.) in a mixer in such
amounts that a glass content of 40 vol. % and a
calcium carbonate content of 2 vol. ~ would be
obtained. The mixture was shaped into pellets with
a pelletizer, and the pellets were fed into an injec-
tion-molding machine. After the injection molding
at a mold temperature of 180C and a cylinder tempera-
ture of 330C, a plate having a size of 1.6 mm x 100
mm x 100 mm was obtained. An adhesive solution [i.e.,
a solution of 20% of NBR (~ipol #1041; a product of
Nippon Zeon Co., ~td., ~% of a phenolic resin (Vercam
TD~2645) of Dai-Nippon Ink Kagaku Co., ~td.) and 16% of an
epoxy resin (Epikote t~l001 of Shell Chemical Co. r Ltd.)
in methyl ethyl ketone] was applied to a copper foil
(35 ~) which had been surface-treated with a zinc/
copper alloy and punched in a circuit pattern. The
thus treateA copper foil was pressed onto the plates
of the polymer B and X at 120.C. After curing at 170C
for 1 hour, printed circui~ boards 4B-l and ~X-l were
obtained.
Separately, the plates of the polymer B and X
were surface-treated with a W solution( 1) at ~0C for
30 minutes, then X aqueous solution( 2) at room tempera-
ture for 3 minutes, ~ aqueous solution( 3) at room
temperature for 5 minutes and Z aqueous solution( 4)
at 70C for 90 minutes to accomplish chemical copper
plating. Thus, copper-plated boards 4B-2 and ~X-2
-68-
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20375-527
havin~ a copper layer thickness of 9 ~ on the average
were obtained.
(l*) W solution: 5 % solution of AlC13 in toluene.
(2*) X aqueous solution: 30 g/liter of SnC12-2H2O
and 15 ml/liter of HCl.
(3*) Y aqueous solution: 0.4 g/liter of PdC12,
15 g/liter of SnC12 and 180 ml/liter of HCl.
(4*) Z aqueous solution: 0.03 m/liter of CUSO4,
0.23 M/liter of NaOH, 0.10 M/liter of HCHO,
0.04 M/liter of EDTA and 50 mg/liter of 2,9-
dimethyl-1,10-phenanthroline.
A copper foil (surface-treated with a zinc/copper
alloy) punched in a circuit pattern was placed in the
mold, and then each of the ~lends of the polymers B
and X was injected to carry out mol.ding. Thus,
printed circui-t boards 4B-3 and 4X-3 were obtained.
The printed ~ixcuit boards thus obtained were
subjected to a soldering heat.resistance test (in which
the sample was immersed in a solder bath at 260~C for
30 minutes, and the appearance thereof was examlned)
and a metal foil-peeling test (JIS C 6481).
The results are shown in Table B-l.
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20375-527
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Sealin~ Agents
Synthesis Example C
(1) 11.0 kg of NMP (N-me-thylpyrrolidone) and
20.0 mol of Na2S 5H2O were charged into a 20-liter
polymerization pressure vessel. The mixture was
heated to about 200C to distill off water and a
small amount of NMP tthe amount of water remaining in
the vessel: 26 mol). A solution of 20.1 mol of p-
dichlorobenzene in 3.0 kg of NMP was added thereto,
and the mixture was heated at 215C for 3 hours.
Then, 54 mol of water was added thereto, and the mix-
ture was heated at 255C for 0.5 hour to obtain a
liquid reaction mixture a, which was taken out and
stored. A small amount of the liquid a was sampled
to determine the average degree of polymerization of
the resulting p-phenylene sulfida prepolymer by the
fluorescent X-ray method. The degree of polymer-
ization was 190.
2.2 kg of NMP and 4.0 mol of Na2S 5H2O were
charged into a 20-liter polymerization pressure vessel.
Tha mixture was heated to about 200C to distill
water and a small amount of NMP (the amount of water
remaining in the vessel: 5.5 mol). A solution of 4.0
mol of m-dichlorobenzene in 0.6 kg of ~MP was added
thereto to obtain a mixture. 80~ of the liquid reac~
tion mixture a obtained as described above and 21.0
mol of water were added to the mixture. The
- 71 -
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mixture was stirred, and reaction was carried out at 255C for 2
hours. After completion of the reaction, the reaction liquid was
diluted about 2 times in volume with NMP and filtered. The filter
cake was washed with hot water 4 times and dried at 80~C under
reduced pressure to obtain a polymer A ~p-phenylene sulfide blocX
copolymer in which the average degree of polymerization of the
S-~- block was 190].
The composition of the polymer A was analyzed by the
FT-IR method to reveal that it comprised 82 molar % of the
( ~ ~ units and 18 molar % of the ( ~ - S-~- units.
The product had a melt viscosity ~* of 690 P as d mined at
310C at a shear rate of 200 sec~l, TG f 73~C and Tm
of 278C~ After heat treatment at 260C for 10 minutes, the
product had a Ci of 33.. TG and Tm were measured with
a differential scanning calorimeter.
-72-
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535
(2) 11.0 kg of NMP and 10.0 mol of Na2S 5H2O were char~ed
into a 20-liter polymerization pressure vessel. The mixture was
heated to about 200C to distill off water and a small amount of
NMP (the amount of water remaining in the vessel: 13 mol). 3.0
kg of NMP, 10.0 mol of m-dichlorobenzene and 0.10 mol of 1,3,5-
trichlorobenzene were added thereto, and reaction was carried out
at 210C for 10 hours. 47 mol of water was added thereto, and the
reaction was carried out at 260C for 12 hours. After completion
of the reaction, a polymer C (m-phenylene sulfide homopolymer)
having a ~* of about 20 P was obtained.
(3) 11.0 kg of NMP and 20.Q mol of Na2S 5H2O were charged
into a 20-liter pressure vessel. The mixture was heated to about
200C to distill off water and a small amount of NMP (the amount of
water remaining in the vessel: 26 mol). 3.0 kg of NMP, 20.2 mol
of p-dichlorobenzene and 54 mol of water were added thereto, and
the mixture was heated at 260C for 3 hours to carry out reaction.
After completion of the reaction, a polymer D ~p-phenylene
sulfide homopolymer) was obtained in the same manner as in (1).
~ * was 610 P.
Molding Example C
Each of the phenylene sulfide polymers was mixed homogeneously
with a speciic amount o an inorganic filler and a specific
amount o an additive in a Henschel* mixex. The mixture was shaped
into pellets by extruding with a 30 mm ~ unidirectional twin screw
extruder at a cylinder temperature of 290 to 330C. The pellets
were injection-molded in a mold having a tran-
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sistor vacant frame inserted therein with an injection-molding
machine at a cylinder temperature of 300 to 340C and mold temper-
ature of 120 to 180C under an injection pressure of 20 to 60
kg/cm2. The sealed products were boiled in a red ink for 24
hours, and penetration of the inX through cracXs in the sealing
resin or through interfaces between the sealing resln and the
frame was examined. The results are shown in Table C-l.
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(*1) silica glass powder: QG-100; a product of Toshiba
Ceramic Co., 150 Mé-passed,
(*2) silane: Z 6040; a product of Dow-Corning Co.,
(*3) epoxy resin: Epikote TM 1009, a product of Shell
Petroleum Co.,
(*4) glass fibers: PF-A001, a product of Nittobo Co.
(48-100 Më),
(*5) glass beads: CP-2, a product of Toshiba PalQdini Co.,
Japan: 150 Mé-passed,
(*6) mica: A 41, a product of Tsuchiya Kaolin CoO, Japan:
(0.05 mm),
~*7) titanate: Kr-134S, a product of Kenrich Petro-chemicals
Co .,
(*8) modified silicone oil: SF 8411; a product of Toray
Silicon Co., Japan.
(*9) Depth of penetration of red ink: l: no penetration, 2:
substantially no penetration, 3: a little, 4:
penetration, 5: remarkable.
(**) 48Mé: opening 0.297 mm, 60 Mé: opening 0.250 mm, lOOMé:
0.149 mm, 150Mé: O.lOS mm.
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