Polyphenylene sulfide composition and method of producing the same

The present invention discloses a composition comprising a mixture containing 100 parts by weight of substantially linear polyphenylene sulfide which is treated with an aqueous solution of an acid or a salt of a strong acid and a weak base and which has not less than 70 mol % of a repeating unit of ##STR1## 0.05 to 5 parts by weight of at least one aminoalkoxysilane compound and, if necessary, 0.01 to 3 parts by weight of a releasing agent, the mixture being kneaded under heating at a temperature higher than the melting point of the polyphenylene sulfide, said composition exhibiting excellent impact strength and weld strength and providing molded product with small amount of flash generated during molding. The invention also discloses a composition which further comprises a fibrous reinforcing material and/or an inorganic powdered or granular filler, according to necessity, as well as disclosing a method of producing said composition.

BACKGROUND OF THE INVENTION 
The present invention relates to a polyphenylene sulfide composition having 
improved melt flow properties and particularly low generation of flashes 
when injection molded, as well as excellent strength at welded part 
(hereinafter referred to as "weld strength") and impact strength and also 
relates to a method producing the same. 
Injection molded products made of a composition of polyphenylene sulfide 
(hereinafter referred to as "PPS") containing a reinforcing fiber or 
filler are excellent in heat resistance and chemical resistance and 
moreover, they have an advantage, which molded product made of other 
engineering plastics do not have, such as excellent electric insulation 
and dimentional stability. Accordingly, PPS is used in many industrial 
fields. 
However, since molecular weight of conventional PPS having not treated 
after its polymerization reaction is low, namely, its melt viscosity is 
too low to be fabricated as it is, to apply such PPS for a practical use, 
so far it can not avoid to be cured with a treatment such as thermal 
treatment under existence of oxygen gas. 
Usually, as such curing is performed with cross-linking, the molded 
products of such polymer is relatively poor in its toughness and even when 
some reinforcing material or filler is added to the polymer, its molded 
products are poor in their impact strength and in their weld strength. 
Accordingly, prompt actions to improve those defects are keenly requested. 
As an example of such improvement, PPS, which is manufactured by the 
process described in U.S. Pat. No. 4,645,826, having a repeating unit of 
##STR2## 
not less than 70 mol% of the total repeating units and a substantially 
linear structure (hereinafter referred to as "the linear PPS") is 
excellent in its toughness. Further, molded products of a composition made 
of the linear PPS have a much better impact strength and weld strength 
than molded products of a conventional PPS composition. This is the reason 
why the linear PPS draw the attention of many people to be suitable for 
the molded products which have many thin parts or the products which have 
a piece of metal in them. However, even when this linear PPS having an 
excellent toughness is fabricated, for example, injection-molded into 
precision molds, it is prone to generate much amount of flash on the 
molds. 
The present inventors have already proposed in Japanese Patent Application 
No. 62-84,110/1987 a method to obtain a composition which has good 
anti-flash property by blending specific silane compound to the linear 
PPS, increasing the melt viscosity and further, raising the dependency of 
the viscosity upon its shear rate. 
Further, as the arts to obtain a composition by blending conventional PPS 
with a silane compound, there are several disclosures, for examples, (1) 
Japanese Patent Application Laid-Open (KOKAI) No. 59-31,503 (1984) 
discloses an electronic part encapsulated with a composition comprising 
PPS and mercaptosilane, being excellent in water resistance and in 
electric properties under high temperature and high humidity, (2) U.S. 
Pat. No. 4,451,601 discloses a composition containing polyarylene sulfide 
and at least one organosilane, having improved anti-hydrolytic property 
and (3) Japanese Patent Application Laid-Open(KOKAI) No. 55-29,526 (1980) 
discloses a composition comprising 100 parts by weight of PPS, 0 to 30 
parts by weight of fillers and 0.01 to 10 parts by weight of 
aminoalkoxysilane or its hydrolytic condensate and being excellent in 
water resistance, humidity resistance and in electric properties. 
Furthermore, Japanese Patent Application Laid-Open (KOKAI) No. 61-285,255 
discloses a composition of PPS containing a fibrous filler and/or another 
silicate filler and a silane compound having at least two unsaturated 
double bonds in its molecular and/or a non-hydrochloride silane compound 
having at least one unsaturated double bond and at least one amino group 
in its molecular, being excellent in its strength and electrical 
properties. 
In these already known arts, the silane compound has been used to improve 
various properties of the composition, namely, (1) adhesion between PPS 
and an inorganic filler and (2) strength, humidity resistance and electric 
properties. Among these improvements, Japanese Patent Application 
Laid-Open (KOKAI) No. 55-29,526 (1980) discloses the increase of its melt 
flow, namely, the reduction of its melt viscosity, by adding 
aminoalkoxysilane to PPS and U.S. Pat. No. 4,451,601 also discloses a 
similar effect to reduce its melt viscosity by adding 
.gamma.-ureidopropyl-triethoxysilane to PPS. Such effect of silane 
compounds to reduce melt viscosity is just contrary to the object of the 
present invention. 
As a result of the present inventors' extensive studies to manufacture a 
composition of the linear PPS being excellent in impact and weld strength 
and having improved anti-flash properties accompanied with high melt 
viscosity with an inexpensive way, they have found the following facts and 
based on these findings, completed the present invention: 
(1) A composition obtained by treating the linear PPS with an aqueous 
solution of an acid or a salt of a strong acid and a weak base, blending 
an aminoalkoxysilane compound to the treated PPS and melt-kneading the 
blend at the temperature higher than melting point of the linear PPS, can 
improve its melt properties, such as, an increase of its melt viscosity 
and an increase of the dependency of the melt viscosity on its shear rate, 
no matter what polymerization degree, that is, what melt viscosity the PPS 
has. Further, the linear PPS without the treatments with said aqueous 
solution can not have such remarkable improvement of its melt property 
after blending an aminoalkoxysilane compound and melt kneading the blend. 
(2) The composition, obtained by treating the linear PPS with the above 
aqueous solution, blending with an aminoalkoxysilane compound and 
melt-kneading, can have an remarkably improved impact strength compared 
with the linear PPS without above treatments or the linear PPS only 
treated with the aqueous solution. Further, this composition can also have 
a largely improved anti-flash property during its molding. However, there 
is a sign that a trace of ejector pin remains on its molded product and 
also a release of the product from the mold does not go smoothly. 
(3) The composition obtained by treating the linear PPS with said aqueous 
solution, blending with an aminoalkoxysilane compound and a releasing 
agent and melt-kneading has somewhat less effect on an improvement of its 
melt property but still has an excellent anti-flash property. Further, 
release of its molded products from the mold proceed smoothly. On the 
other hand, a composition, for comparison, obtained by treating the linear 
PPS with said aqueous solution, blending a releasing agent (without an 
aminoalkoxysilane compound) and melt-kneading has an improved property of 
being released from the mold but has an adverse effect to generate much 
amount of flash making its melt viscosity lower. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a PPS composition which 
has excellent weld and impact strength and has an improved anti-flash 
property. 
An another object of the present invention is to provide a PPS composition 
comprising 100 parts by weight of a polymer which is obtained by treating 
the linear PPS having not less than 70 mol% of a repeating unit of 
##STR3## 
with an aqueous solution of an acid or a salt of a strong acid and a weak 
base; 0.05 to 5 parts by weight of at least one aminoalkoxysilane compound 
and, if necessary, 0.01 to 3 parts by weight of a releasing agent. 
A further object of the present invention is to provide a PPS composition 
further blending a fibrous reinforcing material and/or an inorganic 
non-fibrous filler with the above composition. 
A still another object of the present invention is to provide a method of 
manufacturing the PPS composition. 
DETAILED DESCRIPTION OF THE INVENTION 
A PPS composition of the present invention is obtained by melt-kneading a 
mixture containing 100 parts by weight of PPS which is obtained by 
treating the linear PPS having not less than 70 mol% of a repeating unit 
of paraphenylene sulfide with an aqueous solution of an acid or a salt of 
a strong acid and weak base; 0.05 to 5 parts by weight of at least one 
compound selected from the group consisting of aminoalkoxysilane 
compounds; and, if necessary, 0.01 to 3 parts by weight of a releasing 
agent; at a temperature higher than the melting point of the PPS treated 
with said aqueous solution. This PPS composition has excellent weld and 
impact strengths as well as improved anti-flash property. 
The linear PPS having not less than 70 mol% of a repeating unit of 
paraphenylene sulfide can be produced by a known method, for example, the 
method described in U.S. Pat. No. 4,645,826, that is: 
(1) reacting a dihaloaromatic compound with sodium sulfide at a temperature 
of 180.degree. to 235.degree. C. in the presence of 0.5 to 2.4 moles of 
water per mole of the sodium sulfide in an organic amide solvent to 
produce a polyphenylene sulfide having melt viscosity of 5 to 300 poise 
with the conversion ratio of the dihaloaromatic compound being 50 to 98 
mol%; and 
(2) adding water to the reaction system to make the mole ratio of water to 
sodium sulfide 2.5 to 7.0 and raising the temperature of the system to 
245.degree. to 290.degree. C. and continuing the polymerization reaction. 
By this method, the linear PPS comprising not less than 70 mol% of 
paraphenylene sulfide unit, which is a main constituent of PPS, as a 
repeating unit and of which melt viscosity is in the range of 10 to 30,000 
poise is easily manufactured. 
The term "melt viscosity of a polymer" used in the present application 
represents viscosity measured by using a capillary viscometer equipped 
with a capillary of 10 mm length and 1 mm diameter at 310.degree. C. and a 
shear rate of 1,200/second, unless otherwise specified. 
The term "the linear PPS" used in the present application represents PPS 
which is obtained when no, or not more than 1 mol% of polyfunctional 
monomer is used in the polymerization reaction and the obtained polymer is 
not treated with a known heat curing or, if the curing is performed, the 
melt viscosity of the polymer after curing is less than 3 times that of 
before curing. 
The linear PPS used in the present invention is a polymer which has not 
less than 70 mol%, preferably not less than 80 mol%, of paraphenylene 
sulfide unit as a repeating unit. If the content of the repeating unit is 
less than 70 mol%, the PPS is prone to have a reduced crystallization 
degree, which is a characteristic of the crystalline polymer, and a poor 
strength. The linear PPS of the present invention may also contain less 
than 30 mol% of other repeating unit. Examples of the other repeating 
units include the following: a metaphenylene sulfide unit, 
##STR4## 
a diphenylketone sulfide unit, 
##STR5## 
a diphenylsulfone sulfide unit, 
##STR6## 
A biphenyl sulfide unit, 
##STR7## 
a diphenylether sulfide unit, 
##STR8## 
a 2,6-naphthalene sulfide unit, 
##STR9## 
and a trifunctional unit, 
##STR10## 
The content of the trifunctional unit among these units is preferably not 
more than 1 mol% from the viewpoint not to reduce the crystallization 
degree. 
As the linear PPS of the present invention, homopolymers having a repeating 
unit of paraphenylene sulfide and block copolymers having 70 to 95 mol% of 
a repeating unit of paraphenylene sulfide and 5 to 30 mol% of a repeating 
unit of metaphenylene sulfide are particularly preferable. Examples of 
dihaloaromatic compounds which can be used to produce the linear PPS of 
the present invention are, for example, p-dichlorobenzene, 
m-dichlorobenzene, p-dibromobenzene, 2,6-dichloronaphthalene, 
2,6-dibromonaphthalene, 4,4'-dichlorobiphenyl, 4,4'-dibromobiphenyl, 
4,4'-dichlorodiphenyl ether, 4,4'-dichlorodiphenylsulfone, 
4,4'-dichlorodiphenylketone. 
Examples of organic amide solvents which can be used in the polymerization 
reaction to obtain the linear PPS of the present invention are, for 
example, N-methylpyrrolidone (NMP), N-ethylpyrrolidone, 
N,N'-dimethylformamide, N,N'-dimethylacetoamide, N-methylcaprolactam, 
tetramethylurea, hexamethylphosphoric triamide and mixtures thereof. 
The PPS block copolymer to be preferably used in the present invention can 
be manufactured by the method described in E.P. 166,451 A. For example, 
the block copolymers can be manufactured by a method comprising a first 
step in which an organic amide solvent containing paradihalobenzene and 
sodium sulfide is heated at 160.degree. to 300.degree. C. to produce a 
reaction liquid containing a paraphenylene sulfide having an average 
polymerization degree of 20 to 5,000, and having a repeating unit of (A), 
##STR11## 
a second step in which the dihaloaromatic compound, which essentially 
consist of metadihalobenene, is added to the reaction liquid of the first 
step, the mixture is heated at 160.degree. to 300.degree. C. in the 
presence of sodium sulfide and an organic amide solvent and obtained a 
block copolymer comprising a blocks of an above-mentioned repeating unit 
of (A) and a repeating unit of (B), 
##STR12## 
in the recipe to make mol% of the repeating unit of (A) 70 to 95 mol%. 
The linear PPS to be used in the present invention may be manufactured by 
an another method than described in U.S. Pat. No. 4,645,826 or EP 
166,451A, namely, any method, which can manufacture a substantially linear 
PPS using polycondensation reaction of an dihaloaromatic compound and an 
alkaline metal sulfide and is not limited to PPS manufactured by the above 
methods described particularly in detail. 
The linear PPS to be used in the present invention, is treated with an 
aqueous solution of an acid or a salt of a strong acid and a weak base 
after completion of the polymerization reaction. This treatment with an 
aqueous solution can be economically performed by being incorporated into 
a sequence of steps of the polymerization equipments as an post-treatment 
of the polymer after polymerization. 
As a method to perform the treatment, the method described in EP 216,116A 
can be applied. Namely, a treatment with an aqueous solution of 
hydrochloric acid or sulfuric acid of which pH value is less than 2 or 
with an aqueous solution containing 0.1 to 30% by weight of a salt of a 
strong acid and a weak base (for example, ammonium chloride or ammonium 
sulfate may be exemplified as the salt). Suitable aqueous solutions 
include solutions obtained by using water or mixed solvents containing 
water, as a main component, and an alcohol, a ketone or an ether. 
The linear PPS of the present invention which is treated with an aqueous 
solution of an acid or a salt of a strong acid and a weak base has a melt 
viscosity slightly lower than that of the polymer without the treatment, 
and the melt viscosity in the range of 10 to 20,000 poise is preferable 
and is more preferable in the range of 30 to 10,000 poise. 
One of the objects of the present invention is to obtain a composition 
which has an improved anti-flash property during molding without spoiling 
an excellent toughness and weld strength of the linear PPS. To make the 
composition sufficiently applicable in a practical use, it is necessary to 
contain an inorganic filler or a reinforcing fibers. And, when it comes to 
an injection molding, if the melt viscosity of a composition is over 
20,000 poise, the injection pressure can not avoid to be high, and a large 
molding machine with high mold clamping pressure is therefore required. 
Accordingly, such high melt viscosity is not preferable. 
A composition which can not exhibit its characteristic properties in 
practical use unless relatively large amount of filler is blended (for 
example, a plastic magnet, etc.), it is a common sense in the field to use 
a polymer having low melt viscosity. However, in the present invention, 
the polymer having a melt viscosity of not more than 10 poise can not 
satisfy a necessary tensile strength or an impact strength in many cases 
of practical use. Accordingly, such polymer is not preferable. 
The objects of the present invention cannot be achieved unless an 
aminoalkoxysilane compound is added to the linear PPS which has been 
treated with an aqueous solution of an acid or a salt of a strong acid and 
a weak base, and, if necessary, a releasing agent is added to the PPS and 
the mixture is melt-kneaded at a temperture higher than the melting point 
of the linear PPS treated with the aqueous solution and is blended in a 
uniform composition. In other words, the composition obtained by 
melt-kneading the linear PPS exhibits an increased melt viscosity and 
increased dependency of the melt viscosity on its shear rate, as compared 
with a raw material, the linear PPS, and the composition is good to obtain 
a molded product having an improved anti-flash property as well as 
excellent impact and weld strength. 
Flash generated on the molded products during injection-molding, is formed 
when a molten polymer composition flows into fine gaps designed as parts 
of the mold, on the internal wall of a cavity, during the molten 
composition is filled in the cavity and solidified. 
Although the flash generation depends upon many factors such as a melt 
viscosity, an injection pressure, a holding pressure, a mold temperature 
and a mold clamping pressure, as well as a balance between a cavity and a 
gate, the position of a venting hole and these factors are all relating 
together, in view of the flow properties of a molten polymer, the flash 
generation is suppressed by lowering its melt viscosity at such a place as 
the gate at which the molten polymer receives high shear stress and flows 
at a high speed and by increasing the melt viscosity in such a place as 
inside of the cavity in which the molten polymer receives relatively low 
shear stress and flows at the slightly low speed, namely, by increasing 
the dependency of the melt viscosity on the shear rate. 
The most direct and simple means for increasing the dependency of the melt 
viscosity on the shear rate is to increase the melt viscosity of the 
polymer. However, when a melt viscosity is increased by adding an 
inorganic filler, the effect of suppressing the flash generation can 
hardly be expected unless the melt viscosity of matrix polymer itself is 
increased. 
As an aminoalkoxysilane compound to be added to the linear PPS treated with 
an aqueous solution of an acid or a salt of a strong acid and a weak base, 
amino, (C.sub.1 to C.sub.4)-alkyl, (C.sub.1 to C.sub.4)-alkoxysilanes are 
preferably used, and .gamma.-aminopropyl, tri-(C.sub.1 to 
C.sub.4)-alkoxysilane, which is excellent in its effect and is easily 
available, are more preferably used. 
Examples of aminoalkoxysilane compounds include 
.gamma.-aminopropyltrimethoxysilane, .gamma.-aminopropyltriethoxysilane, 
.gamma.-aminopropylmethyldiethoxysilane, 
N-(.beta.-aminoethyl)-.gamma.-aminopropyltrimethoxysilane, 
N-phenyl-.gamma.-aminopropyltrimethoxysilane and 
.gamma.-ureidopropyltriethoxysilane. 
The amount of the aminoalkoxysilane compound added is 0.05 to 5 parts by 
weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight 
of the linear PPS treated with the aqueous solution. 
The addition of less than 0.05 parts by weight of the compound in some 
cases does not sufficiently produce the effect intended by the present 
invention, and the addition of over 5 parts by weight of the compound is 
prone to generate gases easily during the molding process and to increase 
a production rate of products containing voids. Accordingly, the addition 
of such amounts of the compound is not preferable. 
An Example of the releasing agent which is used according to necessity in 
the present invention is fatty acid esters of polyhydric alcohols, metal 
salts of stearic acid or polyethylene wax or fatty acid bisamide 
compounds. The fatty acid esters of polyhydric alcohols which effectively 
improve releasing properties even with small amounts and produce small 
amounts of gases during the molding process are particularly preferable. 
The amount of the releasing agent to be added according to necessity in the 
present invention is 0.01 to 3 parts by weight, preferably 0.05 to 1.5 
parts by weight, more preferably 0.1 to 1.0 parts by weight, based on 100 
parts by weight of the linear PPS polymer treated with the aqueous 
solution. 
The addition of over 3 parts by weight of the releasing agent is 
undesirable because it reduces the effect of increasing viscosity of the 
composition by the addition of an aminoalkoxysilane compound and moreover, 
it increases the generation of gases during the molding process. The 
addition of less than 0.01 parts by weight of the releasing agent is 
meaningless because no effect can be expected. 
The resin composition of the present invention containing the linear PPS 
treated with the aqueous solution of an acid or a salt of a strong acid 
and a weak base and an aminoalkoxysilane compound or the resin composition 
containing the above components and the releasing agent to be added 
according to the necessity is produced by melt-kneading the mixture for a 
sufficient time to uniformly mix the whole components under a condition of 
the PPS being melted. The condition which the PPS is melted means a state 
at a temperature which is 5.degree. to 100.degree. C. higher than the 
melting point of the PPS. In the present invention, the temperature 
10.degree. to 70.degree. C. higher than the melting point of the PPS is 
preferable. 
The aminoalkoxysilane compound is preferably reacted with the PPS for at 
least 30 seconds, more preferably 30 seconds to 15 minutes, much more 
preferably 1 to 10 minutes, under kneading in a molten state. 
An apparatus used for heating and kneading the composition is not 
particularly limited provided that the apparatus has a heating and 
kneading unit which can generally be used for treating polymers, and a 
single or twin screw extruder having a vent part is preferably used. 
The composition of the present invention essentially contains the linear 
PPS treated with the aqueous solution of an acid or a salt of a strong 
acid and a weak base and the aminoalkoxysilane compound and beside of 
these, may contain other substances such as a releasing agent, a filler, a 
reinforcing material, a stabilizer, a pigment etc., according to 
necessity. 
The filler is selectively used particularly for the purpose of improving 
the dimensional stability, heat conductivity or electrical characteristics 
of the composition. Examples of fillers that can be used include granular 
and powdered mica, silica, talc, alumina, kaoline, titanium oxide, calcium 
sulfate, calcium carbonate, carbon black, graphite and ferrite and other 
magnetic powders. The reinforcing material is used particularly for the 
purpose of improving the mechanical strength in addition to the same 
purpose as the filler. Examples of reinforcing materials that can be used 
include glass fibers, carbon fibers, calcium silicate fibers, potassium 
titanate fibers, alumina fibers, aromatic polyamide fibers and the like. 
The amount of the reinforcing material and/or the filler to be added to the 
composition can be selected with a range which is effective to improve a 
thermal properties and friction properties, for example, within the range 
of 0.1 to 400 parts by weight, preferably 1 to 200 parts by weight, based 
on 100 parts by weight of the PPS. 
The composition of the present invention can contain a small amount of 
another thermoplastic polymer, according to necessity. Examples of 
thermoplastic polymers that can be blended with the composition include 
polyether ether ketone, polyether ketone, polyacrylate, polycarbonate, 
polyether sulfone, modified polyphenylene oxide, polysulfone, polyamide, 
polyethylene terephthalate, polybutylene terephthalate, 
polytetrafluoroethylene and other polyarylene sulfides such as polymers 
having the following repeating unit: 
##STR13## 
The composition of the present invention can be used in the fields of 
injection molding, extrusion molding and others, as the PPS composition 
having excellent mechanical and processing characteristics. 
The PPS composition of the present invention maintains the excellent 
toughness represented by the excellent impact resistance which is a 
characteristic of the linear PPS or further improves the toughness and 
remarkably improves melt properties such as increasing the melt viscosity 
and its dependency on the shear rate, as well as providing injection 
molded products of which the generation of flash is reduced and the weld 
strength is improved. 
The PPS composition of the present invention also exhibits excellent 
releasing property and is suitable to obtain precision molded products in 
a high yield, particularly thin molded products and injection molded 
products which are designed to have metal parts forced into them and which 
have complicated shapes. 
The present invention is described in detail below with reference to the 
examples, but the invention is not limited only to the scope described in 
the examples.

SYNTHETIC EXPERIMENTAL EXAMPLE 1 (Synthesis of Polyparaphenylene Sulfide) 
920 kg of N-methylpyrrolidone (hereinafter referred to as NMP) and 424 kg 
of Na.sub.2 S.5H.sub.2 O (containing 46.07% by weight of Na.sub.2 S) were 
charged in an autoclave and 168 kg of water was then distilled out by 
gradually raising the temperature of the mixture to 203.degree. C. 
5 kg of water and 50 kg of NMP were added to the residue, and 362 kg of 
paradichlorobenzene was then charged in the autoclave and the 
polymerization reaction was performed at 220.degree. C. for 5 hours. 69 kg 
of water was then added to the reaction liquid and further subjected to 
polymerization reaction at 255.degree. C. for 5 hours. After cooling the 
reaction mixture, a granular polymer was separated with a screen having 
0.1 mm openings. The granular polymer was then washed with acetone and 
water to obtain a wet granular polymer. About 1/3 of the wet polymer was 
dried as it was to obtain a polymer (1-A). The melting point of the 
polymer (1-A) was 280.degree. C. and the melt viscosity was 1,140 poise. 
On the other hand, half the remaining polymer was immersed in an aqueous 
solution of 2% by weight NH.sub.4 Cl to be treated at 40.degree. C. for 30 
minutes under agitation. The treated polymer was washed with water and 
dried to obtain a polymer (1-B). Further, half of the remaining wet 
polymer was immersed in an aqueous solution of hydrochloric acid, of which 
pH value is 1, and treated at 40.degree. C. for 30 minutes. The treated 
polymer was neutralized with ammonia water, washed with water and dried to 
obtain a polymer (1-C). 
SYNTHETIC EXPERIMENTAL EXAMPLE 2 (Synthesis of PPS) 
930 kg of NMP and 423 kg of Na.sub.2 S.5H.sub.2 O (containing 46.07% by 
weight of Na.sub.2 S) were charged in an autoclave and 170 kg of water was 
then distilled out by gradually raising the temperature of the mixture to 
203.degree. C. 4 kg of water and 43 kg of NMP were added to the mixture, 
and 365 kg of paradichlorobenzene was charged in the autoclave and the 
polymerization reaction was performed at 220.degree. C. for 5 hours. 135 
kg of water was added to the reaction mixture and further polymerized at 
255.degree. C. for 4.5 hours. 
After cooling the reaction mixture, a granular polymer was separated with a 
screen having 0.1 mm openings. The granular polymer was then washed with 
acetone and water to obtain a wet granular polymer. About half of the wet 
granular polymer was dried as it was to obtain a polymer (2-A). The 
melting point of polymer (2-A) was 283.degree. C. and its melt viscosity 
was 600 poise. The remaining granular polymer was treated with an aqueous 
solution of 2% by weight NH.sub.4 Cl in the same way used in Synthetic 
Experimental Example 1, washed with water and dried to obtain a polymer 
(2-B). 
SYNTHETIC EXPERIMENTAL EXAMPLE 3 (Synthesis of Paraphenylene 
Sulfide-Metaphenylene Sulfide Block Copolymer) 
(a) 80 kg of NMP and 37.0 kg of Na.sub.2 S.5H.sub.2 O (containing 45.9% by 
weight of Na.sub.2 S) were charged in an autoclave and 14.9 kg of water 
and 12.8 kg of NMP were distilled out by gradually raising the temperature 
of the mixture to 200.degree. C. 31.0 kg of metadichlorobenzene, 40 kg of 
NMP and 1.0 kg of water were then added to the mixture, followed by 
polymerization at 220.degree. C. for 2 hours and then at 230.degree. C. 
for 5 hours. 
(b) 75 kg of NMP and 30.5 kg of Na.sub.2 S.5H.sub.2 O (containing 45.9% by 
weight of Na.sub.2 S) were charged in another autoclave, and 12.8 kg of 
water and 13.7 kg of NMP were distilled out by gradually raising the 
temperature of the mixture to 200.degree. C. 26.5 kg of 
paradichlorobenzene, 25 kg of NMP, 1.0 kg of water and 23.5 kg of the 
polymetaphenylene sulfide slurry obtained in (a) were added to the 
mixture, followed by polymerization at 220.degree. C. for 10 hours. 13.0 
kg of water was added to the reaction liquid and further subjected to 
polymerization at 260.degree. C. for 5 hours. 
After cooling the reaction liquid, a granular polymer was separated with a 
screen having 0.1 mm openings. The granular polymer was then washed with 
acetone and water to obtain a wet polymer. About half of the wet polymer 
was dried as it was to obtain a polymer (3-A) (melting point, 275.degree. 
C., melt viscosity, 1,300 poise). 
Further, the remaining polymer mixture was treated with an aqueous solution 
of 2% by weight of NH.sub.4 Cl, washed with water, dried and obtained 
polymer (3-B) (melting point, 275.degree. C.; melt viscosity, 1,300 
poise). 
The results of analysis of the block copolymers with infrared absorption 
spectra indicate that the ratio of paraphenylene sulfide to metaphenylene 
sulfide of each of the copolymers was 85:15. 
SYNTHETIC EXPERIMENTAL EXAMPLE 4 
A PPS polymer (4) treated with an aqueous solution of 2% by weight of 
NH.sub.4 Cl (melting point, 284.degree. C.; melt viscosity, 370 poise) was 
obtained by the same method as employed in Synthetic Experimental Example 
2 with the exception that 370 kg of paradichlorobenzene was charged in an 
autoclave. 
EXAMPLES 1 to 2 AND COMATIVE EXAMPLES 1 to 4 
A PPS polymer (4) obtained in Synthetic Experimental Example 4 was 
preliminarily mixed with .gamma.-aminopropyltriethoxysilane A-1100 
(hereinafter referred to as AS-1; manufactured by NIPPON UNIKA Co. Ltd.), 
glass fibers (diameter; 13 .mu.m; manufactured by NIPPON Electric Glass 
Co., Ltd.) and neopentylglycol distearate as a releasing agent in the 
ratios shown in Table 1. Each of the mixtures was kneaded for 3 minutes at 
a cylinder temperature of 320.degree. C. and then extruded with a 
co-rotating twin-screw kneading extruder into pellets. The procedure for 
preliminary mixing was as follows: 
The PPS and an aminoalkoxysilane compound were first mixed with a Henschel 
mixer, a releasing agent was then added to the mixture and again mixed by 
the Henschel mixer and glass fibers were finally added to the mixture and 
mixed by a tumbler mixer. 
Melt viscosities of these pellets were measured with a Capillograph, having 
a nozzle of L/D=10 mm/1 mm, (manufactured by TOYO SEIKI Co., Ltd.) at 
310.degree. C. The results of the measurements are in Table 1. 
To indicate the index for the dependency of melt viscosity on the shear 
rate, ratio of the melt viscosities at a shear rate of 200/second and at 
the rate of 1,200/second are calculated and the results are also in Table 
1. The higher ratio means the higher dependency of melt viscosity on the 
shear rate. 
The test piece of each pellet to measure physical properties are prepared 
by injection molding machine (temperature of the mold=145.degree. C.). 
The various physical properties of the test pieces (without heat treatment) 
were measured and the results are in Table 2. 
It can be seen from Table 1 that the melt viscosity and its dependency on 
the shear rate of PPS (4) treated with an aqueous solution of 2% by weight 
of NH.sub.4 Cl are significantly increased owing to the reaction of PPS 
with the aminoalkoxysilane. 
It can also be seen from Table 2 that the mechanical strength of the PPS 
composition reacted with an aminoalkoxysilane is relatively better than 
that of the unreacted PPS and that the composition containing both an 
aminoalkoxysilane and a releasing agent is well-balanced with respect to 
the reduction ratio of flash generation and the releasing property. The 
degree of flash generation was decided by measuring the length of flash 
generated on each test piece. 
The length of a flash was measured by an enlarged photograph, and its 
evaluation was decided by the following three criteria: 
(X): The length of a flash is not less than B 0.5 mm and there is a problem 
in practical use. 
(.DELTA.): The length of a flash is about 0.3 mm and there is no 
significant problem in practical use, although a small flash exists. 
(O): The length of a flash is not more than 0.2 mm and there is no problem 
in practical use. 
The releasing property was determined by injection molding test pieces, 
under constant molding conditions, using a box-shaped mold with an inner 
size of 40 mm.times.60 mm and a thickness of 4 mm (the temperature of the 
mold; cavity side, 147.degree. C.; core side, 176.degree. C.) and 
measuring the time (injection time+cooling time) taken until no mark of 
the ejector pin used was remained on a molded product at the releasing. 
The length of the time was used as an index of the releasing property and 
are in Table 2. 
TABLE 1 
__________________________________________________________________________ 
Amount of 
Silane 
Amount of 
Amount of 
Melt Viscosity at 310.degree. C. 
(poise) 
Polymer Compound 
Releasing 
Glass Fibers 
Shear Rate Ratio of 
Type Amount 
(*.sup.1) 
Agent(*.sup.2) 
(13 .mu.m.phi.) 
200/sec (I) 
1200/sec (II) 
I/II 
__________________________________________________________________________ 
Com. Ex 1 
4 100 -- -- -- 500 370 1.35 
Ex. 1-1 
4 100 0.8 -- -- 950 630 1.51 
Ex. 1-2 
4 100 0.8 0.3 -- 1000 660 1.52 
Com. Ex 2 
4 100 -- 0.3 -- 450 360 1.25 
Com. Ex 3 
4 100 -- -- 66.7 2000 1200 1.67 
Ex. 2-1 
4 100 0.83 -- 66.7 2800 1500 1.87 
Ex. 2-2 
4 100 0.83 0.33 66.7 2600 1400 1.86 
Com. Ex 4 
4 100 -- 0.33 66.7 2000 1200 1.67 
__________________________________________________________________________ 
Note: 
All amounts are part by weight. 
Com. Ex. means Comparative Example and Ex. means Example. 
(*.sup.1)AS1; 
(*.sup.2)Neopentylglycol distearate 
TABLE 2 
__________________________________________________________________________ 
Physical Properties of Injection Molded Product(As Molded) 
Flexural 
Flexural 
Tensile Impact(*.sup.5) 
Degree of 
Strength 
Modulus 
Strength 
Elongation 
Strength 
Flash(*.sup.6) 
Releasing 
(kg/mm.sup.2)(*.sup.1) 
(kg/mm.sup.2)(*.sup.2) 
(kg/mm.sup.2)(*.sup.3) 
(%)(*.sup.4) 
(kg-cm/cm) 
Generation 
Property(*.sup.7) 
__________________________________________________________________________ 
Com. Ex. 1 
11.3 430 7.2 2.0 17 X .DELTA. 
Example 1-1 
12.9 423 8.6 2.6 41 .DELTA. 
X 
Example 1-2 
12.5 426 9.4 3.5 36 .DELTA. 
O 
Com. Ex. 2 
12.5 432 8.0 2.2 25 X O 
Com. Ex. 3 
25.6 1670 17.5 1.3 33 .DELTA. 
.DELTA. 
Example 2-1 
26.8 1660 17.1 1.3 41 O X 
Example 2-2 
26.4 1660 17.8 1.4 41 O O 
Com. Ex. 4 
26.0 1670 17.1 1.3 33 .DELTA. 
O 
__________________________________________________________________________ 
(*.sup.1)Measured by ASTM D790 
(*.sup.2)Measured by ASTM D638 
(*.sup.3)Measured by ASTM D638 
(*.sup.4)Measured by ASTM D638 
(*.sup.5)Measured by ASTM D256 (without notch) 
(*.sup.6)Refer to pages 18 and 19. 
(*.sup.7)The criteria of the releasing property are as follows: 
O: Less than 70 seconds 
.DELTA.: Less than 70 to 80 seconds 
X: over 80 seconds 
EXAMPLES 3 TO 10 AND COMATIVE EXAMPLES 5 TO 16 
As PPS, each granular PPS obtained in the Synthetic Experimental Examples 1 
to 3 or a commercially available PPS, which is thermally cured, is used 
and as an aminoalkoxysilane, AS-1, 
N-(.beta.-aminoethyl)-.gamma.-aminopropyltrimethoxysilane (Code no. 
A-1120; manufactured by NIPPON UNIKA Co., Ltd.) or 
.gamma.-ureidopropyltriethoxysilane (Code no. A-1160; manufactured by 
NIPPON UNIKA Co., Ltd.) is preliminarily blended with 100 parts by weight 
of above PPS, in an amount shown in Table 3, by Henschel mixer at room 
temperature for 5 minutes. At the same time, 0.2 part by weight of 
neopentylglycol distealate is also blended with the PPS. 
Each blend was extruded with a co-rotating twin-screw kneading extruder 
(Plastic Engineering Institute BT-30) into pellets at the cylinder 
temperature of 320.degree. C. 
The melt viscosity of each sample was measured according to the method 
described in page 18 and the results are in Table 3. 
The ratio of the melt viscosities at shear rates of 200/second and 
1,200/second was used as an index expressing the dependency of the melt 
viscosity of the shear rate. 
As can be seen from Table 3, only the mixture of an aminoalkoxysilane and 
the PPS treated with hydrochloric acid or NH.sub.4 Cl can leads to 
increase viscosity and its dependency on the shear rate. 
TABLE 3 
__________________________________________________________________________ 
Melt Viscosity at 310.degree. C. 
(poise) 
Type of 
Aminoalkoxysilane Shear rate Ratio 
Polymer 
Type Amount 
200/sec. (I) 
1200/sec. 
I/II 
__________________________________________________________________________ 
Com. Ex. 10 
1-A .gamma.-aminopropyltriethoxysilane 
0.8 1770 1250 1.42 
Com. Ex. 11 
1-A -- 0 1610 1140 1.41 
Example 8 
1-B .gamma.-aminopropyltriethoxysilane 
0.8 5400 2800 1.93 
Com. Ex. 6 
1-B -- 0 1390 1000 1.39 
Example 10 
1-C .gamma.-aminopropyltriethoxysilane 
0.8 5500 2850 1.93 
Com. Ex. 12 
1-C -- 0 1350 980 1.38 
Com. Ex. 8 
2-A .gamma.-aminopropyltriethoxysilane 
0.8 820 630 1.30 
Com. Ex. 9 
2-A -- 0 780 600 1.30 
Example 3 
2-B .gamma.-aminopropyltriethoxysilane 
0.8 1100 730 1.51 
Example 4 
2-B .gamma.-aminopropyltriethoxysilane 
1.5 2200 1200 1.83 
Example 5 
2-B .gamma.-aminopropyltriethoxysilane 
2.0 2700 1400 1.93 
Com. Ex. 5 
2-B -- 0 700 560 1.25 
Example 6 
2-B N-(.beta.-aminoethyl)-.gamma.-aminopropyltrimethoxysilane 
0.8 980 750 1.31 
Example 7 
2-B .gamma.-ureidopropyltriethoxysilane 
0.8 860 660 1.30 
Com. Ex. 15 
3-A .gamma.-aminopropyltriethoxysilane 
0.8 2020 1420 1.42 
Com. Ex. 16 
3-A -- 0 1840 1300 1.42 
Example 9 
3-B .gamma.-aminopropyltriethoxysilane 
0.8 6300 3300 1.91 
Com. Ex. 7 
3-B -- 0 1630 1190 1.37 
Com. Ex. 13 
(*1) .gamma.-aminopropyltriethoxysilane 
0.8 2300 1100 2.09 
Com. Ex. 14 
(*1) -- 0 2700 1300 2.08 
__________________________________________________________________________ 
Amounts is part by weight 
(*.sup.1)Thermally cured PPS. 
EXAMPLE 11 and COMATIVE EXAMPLE 17 
Polymer (1-B) obtained in Synthetic Experimental Example 1 was blended with 
.gamma.-aminopropyltriethoxysilane as an aminoalkoxysilane, glass fibers 
having a diameter of 13 .mu.m (produced by NIPPON Electric Glass Co., 
Ltd.) and pentaerythritol tetrastearate as a releasing agent in the ratios 
shown in Table 4. Each blend obtained was melt-kneaded and pelletized by 
melt extrusion in the same manner as in the above Examples. 
The procedure for blending was as follows: 
The PPS and the aminoalkoxysilane were first blended by a Henschel mixer, 
then the releasing agent was blended with the obtained blend by the same 
Henschel mixer, and finally the glass fibers were blended by a tumbler 
mixer. 
The value of melt viscosity of the pellets were measured according to the 
method described in page 18. 
The pellets of each composition were fabricated in test pieces for 
measuring the physical properties by an injection molding machine (mold 
temperature, 145.degree. C. and cylinder temperature, 310.degree. C.). 
These test pieces (as molded) were used for evaluating the physical 
properties and the degree of flash generation and measuring the weld 
strength and releasing property. 
The results of tests are in Tables 4 and 5. 
As can be seen from these tables, the melt viscosity and the dependency 
thereof on the shear rate of the composition containing an 
aminoalkoxysilane compound are higher than those of the composition 
containing no aminoalkoxysilane compound. 
As can also be seen from these tables, the composition containing both the 
aminoalkoxysilane compound and the releasing agent exhibits increased 
tensile strength and elongation, a reduced amount of flash and 
well-balanced relationship between the weld strength and the releasing 
property, as compared with those of the composition containing none of the 
aminoalkoxysilane compound and the releasing agent. 
TABLE 4 
__________________________________________________________________________ 
Polymer/Glass 
.gamma.-amino- Melt viscosity at 310.degree. C. 
(poise) 
Fiber propyltri- 
Pentaerythritol 
Shear Rate Ratio 
Polymer 
(ratio by weight) 
ethoxysilane(*.sup.1) 
tetrastearate(*.sup.1) 
200/sec. (I) 
1200/sec. (II) 
I/II 
__________________________________________________________________________ 
Com. Ex. 17 
1-B 60/40 0 0 4500 2500 1.80 
Example 11-1 
1-B 60/40 0.5 0 7000 3400 2.06 
Example 11-2 
1-B 60/40 0.5 0.2 5800 2900 2.00 
__________________________________________________________________________ 
(*.sup.1)parts by weight based on 100 parts by weight of the polymer 
TABLE 5 
__________________________________________________________________________ 
Tensile Strength 
Elongation 
Degree of Flash 
Releasing 
Weld strength 
(kg/mm.sup.2) 
(%) Generation (*.sup.1) 
Property (*.sup.2) 
(kg/mm.sup.2) 
__________________________________________________________________________ 
Com. Ex. 17 
17.0 1.4 .DELTA. .DELTA. 
9.6 
Example 11-1 
18.4 1.7 O .DELTA. 
10.1 
Example 11-2 
18.4 1.7 O O 10.1 
__________________________________________________________________________ 
(*.sup.1)Refer to pages 18 and 19. 
(*.sup.2)Refer to Table 2.