CA1272535A - Para-phenylene sulfie block copolymers process for the production of the same and use thereof - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Disclosed is a para-phenylene sulfide block copolymer comprising a recurring unit (A) . The recurring units (A) are present in the form of a block of 20 to 5,000 units of (A) on the average in the molecular chain, and the mol fraction of the recurring units (A) is in the range of 0.50 to 0.98.
The block copolymer has a melt viscosity (?*) of 10 to 100,000 poise as determined at 310°C at a shear rate of 200 sec-1 and may have:
(a) a glass transition temperature (Tg) of 20 to 80°C, (b) a crystalline melting point (Tm) of 200 to 350°C, and (c) a crystallization index (Ci) of 15 to 45, this value being that of the heat-treated, but not stretch-oriented copolymer. Also disclosed is use of the block copolymer, including for producing molded articles and for producing printed circuit boards.

Description

~ 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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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 ., .
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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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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 ., ': ' ~. " ' ~L~'7;~

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 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~

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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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.

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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 --10~

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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-:, ,' ,. :, . ..

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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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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 i ~

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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~

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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 . . .
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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.

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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, :

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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 ,.,: , ~ :
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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 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 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.

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~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 1.~, . .
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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.

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.

. ~

,. ..
..

~,. ..

'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, ..' ' ~

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).

.

, ::

r ~L~ 7 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 : :; ~ :
.. ~; -: -.
:. . . ,. - . . . :
::: . -:
: ~,: ~ .
.. ...

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 : : .:. , : ::
,.. .

::--- ::: ,:: :
.: .~

~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 1~7~53~

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 , . ~- . . .

'7~S35 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 .:

~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 . . :. : .. -.
.. , ~ : .
- -' '" ' ~, '' ' ~ 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

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-~;~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 7~5~

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 ~ ~ .
':

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 .. ~. .

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/

: " ~- ' ' : :,

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 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) - : :
'., ::.

.
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~;~'7~ 5 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 .
. ", . . ~ , ~Z7~

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 3~.~7 .~

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` ~
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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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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 :

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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 ' '; ' 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 - - . . : , . . .

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~.

.:.: `i; ' :
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, 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.

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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 ~7~535 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 .. .. .

. .
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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.

, ~ ~ , ...
, 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 :., ,, .: . '~:
: : :
. . .
..

- ~ ~7 ~3~

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-.. .

S3~

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 .", ~ , , , ~

... . .

~:

~.~7Z~3~5 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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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 ' :

i3S
~, ~,,,,--.,, 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.

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' (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-*Trade Mark - ..:-~ :-~;~'7~
~A~ ~

GU~ / J--J~,, 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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_ m O ~ ~ H- a ~75--.: . . ..

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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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. . .
:,-.,.. :: ,, ,

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A printed circuit board composed of [i] an insulating base plate molded from a composite of 50 to 95 volume % of a polymer comprising mainly a phenylene sulfide block copolymer and 5 to 50 volume % of a non-electroconductive fibrous rein-forcing material and [ii] a metal layer of a circuit pattern formed on a surface of the base plate, wherein the said pheny-lene sulfide block copolymer comprises 20 to 5,000 recurring units on the average in the molecular chain, the said recurring unit has a mol fraction of 0.50 to 0.98 and the said copolymer has a melt viscosity (?*) of 300 to 50,000 poise as determined at 310°C at a shear rate of 200 sec-1 and a crystalline melting point of 200 to 350°C.

2. A para-phenylene sulfide block copolymer consisting essentially of a recurring unit (A) and a recurring unit (B) , the said recurring units (A) being present in the form a block of 20 to 5,000 units of (A) on the average in the molecular chain, the mol fraction of the recurring units (A) being in the range of 0.50 to 0.98, the block copolymer having a melt viscosity (?*) of 1,000 to 50,000 poise as determined at 310°C at a shear rate of 200 sec-1 and having:
(a) a glass transition temperature (Tg) of 20 to 80°C, (b) a crystalline melting point (Tm) of 250 to 285°C, and (c) a crystallization index (Ci) of 15 to 45, this value being that of the heat-treated, but not stretch-oriented copolymer.

3. A molded article produced from a p-phenylene sulfide block copolymer consisting essentially of recurring units (A) and recurring units (B) , said recurring units (A) being present in the form of a block of 20 to 5,000 units of (A) on the average in the molecular chain, the mol fraction of the recurring units (A) being in the range of 0.50 to 0.98, the block copolymer having a melt viscosity (?*) of 1,000 to 50,000 poise as determined at 310°C at a shear rate of 200 sec-1 and having:
(a) a glass transition temperature (Tg) of 20 to 80°C, (b) a crystalline melting point (Tm) of 250 to 285°C, and (c) a crystallization index (Ci) of 15 to 45, this value being that of the heat-treated t but not draw-oriented copoly-mer.

4. The article according to Claim 3 which is in the form of film or fiber.

5. The article according to Claim 3 which is an injection-molded product, extrusion-molded product or electric wire coating.

6. The printed circuit board according to Claim 1, wherein the other recurring unit of the block copolymer is ;
the block copolymer has a melt viscosity of 7,000 to 50,000 poise as determined at 310°C at a shear rate of 200 sec-1, a glass transition temperature (Tg) of 20 to 80°C, a crystalline melting point of 250 to 285°C and a crystallization index (Ci) of 15 to 45, this value being that of the heat-treated, but not stretch-oriented copolymer.

7. The printed circuit board according to Claim 6, wherein the block copolymer comprises 40 to 3,500 recurring units and the mol fraction of the recurring unit is 0.60 to 0.90.

8. The block copolymer according to Claim 2, wherein the block copolymer comprises 40 to 3,500 recurring units and the mol fraction of the recurring unit is 0.60 to 0.90.

9. The molded article according to Claim 3, 4 or 5, wherein the block copolymer comprises 40 to 3,500 recurring units and the mol fraction of the recurring unit is 0.60 to 0.90.

10. The molded article according to Claim 3, 4 or 5, wherein the block copolymer is employed in admixture with a powdery in-organic filler or a fibrous filler.