JPH0971723A - Polyarylene sulfide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PAS resin composition having improved degree of whiteness without changing the melt viscosity inherent in a PAS and without detriment to mechanical strengths such as tensile strength. SOLUTION: This polyarylene sulfide resin composition comprises 100 pts.wt. polyarylene sulfide and 0.01-15 pts.wt. silica having a pore volume of 1.00ml/g or below and a mean pore diameter of 100Å or below.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyarylene sulfide resin composition, and more particularly to a polyarylene sulfide resin composition having an excellent hue.

[0002]

2. Description of the Related Art Conventionally, the hue of polyarylene sulfide (hereinafter sometimes abbreviated as PAS) is improved, and
Various measures have been taken to reduce discoloration.

For example, a method is known in which a halo-substituted organic compound such as a polyhaloaromatic compound is added to the polymerization system in the latter stage of the polymerization to stabilize the polymer chain end (Japanese Patent Laid-Open No. 62-62-62).
No. 97821). However, a drawback has been found that the melt viscosity tends to be small. White pigment is polyphenylene sulfide (hereinafter sometimes abbreviated as PPS)
It has been proposed to mix the resin with a white color to compensate for the decrease in mechanical strength caused by the addition of a white pigment by adding an epoxy resin (JP-A-60-8359). However, this leads to high costs. Titanium oxide and zinc sulfide are described as white pigments. Although silica is mentioned in the illustration of the optional reinforcement, there is no further mention of silica. Further, in a composition composed of PAS and an inorganic filler, a method is known in which an organic stabilizer is previously attached to the surface of the composition in order to prevent discoloration due to the inorganic filler (Japanese Patent Laid-Open No. 3-229760). Issue). However, there are drawbacks that the melt viscosity becomes small during the melt molding and decomposition gas is generated.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a PAS having improved whiteness without changing the original melt viscosity of PAS and without lowering mechanical strength such as tensile strength.
A resin composition is provided.

[0005]

Means for Solving the Problems The present inventors have made various studies in order to solve the above problems. As a result, PAS
It has been found that all of the above problems can be solved by incorporating silica having the following predetermined properties into the present invention, and has completed the present invention.

That is, the present invention relates to (1) 100 parts by weight of (A) polyarylene sulfide and (B) a silica having a pore volume of 1.00 ml / g or less and an average pore diameter of 100 Å or less. A polyarylene sulfide resin composition containing 0.01 to 15 parts by weight.

In a preferred embodiment, (2) the silica (B) has a pore volume of 0.20 to 0.90 m.
The resin composition according to the above (1), which has an average pore size of 20 to 80 Å, and (3) (B) the silica has an average particle size of 1.0 to 10 μm. Alternatively, the resin composition described in (2) can be mentioned.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The upper limit of the pore volume of (B) silica used in the present invention is 1.00 ml / g, preferably 0.1.
90 ml / g, particularly preferably 0.85 ml / g, and the lower limit is preferably 0.20 ml / g, particularly preferably 0.30 ml / g. If the upper limit is exceeded, PA
This is not preferable because the melt viscosity V ₆ of the S resin composition increases. The upper limit of the average pore size of silica (B) is 100 angstroms, preferably 80 angstroms, particularly preferably 70 angstroms, and the lower limit is preferably 20 angstroms, particularly preferably 25 angstroms. Exceeding the above upper limit is not preferable because the melt viscosity V ₆ of the PAS resin composition increases and the processability deteriorates. Here, the above-mentioned pore volume and average pore diameter are obtained by analyzing the hysteresis of the adsorption isotherm of gas by the Kelvin equation.

The upper limit of the average particle size of the (B) silica used in the present invention is preferably 10 μm, particularly preferably 6.0.
μm, and the lower limit is preferably 1.0 μm, particularly preferably 2.0 μm. Here, the average particle size is a value obtained by the Coal counter method (D ₅₀ ). If the average particle size exceeds the above upper limit, not only the dispersibility deteriorates, but also the effect of the present invention cannot be obtained. If it is less than the above lower limit, the melt viscosity V ₆ of the PAS resin composition is increased. The silica particles preferably have a particle size distribution of 90% by weight or more of particles having a particle size of 8 μm or less, and particularly preferably a particle size of 9 μm.
95% by weight or more of particles having a size of μm or less is preferable.

The silica (B) is not particularly limited as long as it has the above properties. Preferably, colloidal silica is used, and for example, silica silicate and sulfuric acid are mixed using high-purity silica sand as a raw material to generate a silicic acid sol, and these silicic acid sols are polymerized to form an aggregate to form a sol. What was manufactured by the method etc. which can be used can be used. Examples of commercially available products include Cysilia 730, Cysilia 740, Cysilia 770, Cysilia 530, Cysilia 540, and Cysilia 550 (all are trademarks) manufactured by Fuji Silysia Ltd.

Component (A) PAS used in the resin composition of the present invention is a known polymer having an arylene sulfide repeating unit, and particularly preferably polyphenylene sulfide.

The method for producing (A) PAS of the present invention is not particularly limited. For example, a method of reacting a dihalo aromatic compound and an alkali metal sulfide in an organic amide solvent (Japanese Patent Publication No.
5-3368) and the like can be used.

Preferably, the gas phase portion of the reactor is cooled,
A method of refluxing a part of the gas phase into the liquid phase (Japanese Patent Laid-Open No. 5-22
2196). The PAS produced by the method is a relatively high molecular weight PAS having a substantially linear structure and is preferable because it is excellent in mechanical strength such as tensile strength. That is, the method comprises reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide-based solvent to form P
In the method for producing AS, a part of the gas phase in the reaction can is condensed by cooling the gas phase part of the reaction can, and this is refluxed to the liquid phase. .

In the PAS manufacturing method, the refluxed liquid has a higher water content than that of the liquid phase bulk because of the vapor pressure difference between water and the amide solvent. The reflux liquid having a high water content forms a layer having a high water content at the upper portion of the reaction solution. As a result, residual alkali metal sulfides (eg Na ₂ S),
Alkali metal halides (eg, NaCl), oligomers, and the like are included in the layer in large amounts. In the conventional method, PAS and N
In a state where the raw materials such as a ₂ S and by-products are uniformly mixed, not only a high molecular weight PAS cannot be obtained, but also
Depolymerization of PAS produced with great care also occurs, and thiophenol by-product is observed. However, in the present invention, the above disadvantageous phenomenon can be avoided by actively cooling the gas phase portion of the reaction vessel and returning a large amount of the water-rich reflux liquid to the upper part of the liquid phase so as to inhibit the reaction. It can be considered that such factors can be effectively eliminated and a high molecular weight PAS can be obtained. However, the present invention is not limited only by the effect of the above phenomenon, but by various effects caused by cooling the gas phase part, high molecular weight PAS
Is obtained.

In this method, it is not necessary to add water during the reaction. However, this does not preclude the addition of water at all. However, with the addition of water, some of the advantages of this method are lost. Therefore, preferably, the total water content in the polymerization reaction system is constant throughout the reaction.

The gas phase portion of the reaction can can be cooled by external cooling or internal cooling, and can be performed by a cooling means known per se. For example, a method of flowing a cooling medium through an internal coil installed at an upper part in a reaction can, a method of flowing a cooling medium through an external coil or a jacket wrapped around the upper part of the reaction can, and using a reflux condenser installed at the upper part of the reaction can A method such as spraying water or blowing a gas (air, nitrogen, etc.) on the upper portion of the outside of the reaction vessel is conceivable, but any method can be used as long as it has the effect of increasing the amount of reflux in the vessel as a result. May be used. If the outside air temperature is relatively low (for example, normal temperature), appropriate cooling can be performed by removing a heat insulating material conventionally provided on the upper part of the reaction vessel. In the case of external cooling, water condensed on the reactor wall
The amide-based solvent mixture enters the liquid phase along the reaction vessel wall. Thus, the water-rich mixture pools on top of the liquid phase,
Keep the water content there relatively high. For internal cooling,
The mixture condensed on the cooling surface likewise travels down the cooling device surface or the reactor wall and into the liquid phase.

On the other hand, the temperature of the liquid phase bulk is maintained at a predetermined constant temperature or controlled according to a predetermined temperature profile. 230 to 275 for constant temperature
It is preferred to carry out the reaction at a temperature of ° C for 0.1 to 20 hours. More preferably, the temperature is 240 to 265 ° C for 1 to 6 hours. To obtain higher molecular weight PAS, it is preferable to use a reaction temperature profile of two or more steps. This 2
When carrying out the stepwise operation, the first step is preferably carried out at a temperature of 195 to 240 ° C. If the temperature is low, the reaction rate is too low, which is not practical. If the temperature is higher than 240 ° C., the reaction rate is too fast, PAS having a sufficiently high molecular weight cannot be obtained, and the side reaction rate remarkably increases. The end of the first phase,
Dihalo aromatic compound residual rate in the polymerization reaction system is 1 mol% to 40
It is preferable to carry out the reaction at a time point when the molar% is within the range of 3,000 to 20,000. More preferably, the residual ratio of the dihalo aromatic compound in the polymerization reaction system is in the range of 2 mol% to 15 mol%, and the molecular weight is in the range of 5,000 to 15,000. Residual rate is 40 mol%
When it is more than 1, the side reaction such as depolymerization is likely to occur in the second step reaction, while when it is less than 1 mol%, the high molecular weight P is finally obtained.
It is hard to get AS. Thereafter, the temperature is raised, and the reaction in the final stage is preferably carried out at a reaction temperature of 240 to 270 ° C. for 1 to 10 hours. PAS with sufficiently high molecular weight at low temperature
When the temperature is higher than 270 ° C., side reactions such as depolymerization are liable to occur, making it difficult to stably obtain a high molecular weight product.

As a practical operation, first, dehydration or water addition is carried out in an inert gas atmosphere so that the amount of water in the alkali metal sulfide in the amide solvent becomes a predetermined amount, if necessary. The water content is preferably the alkali metal sulfide 1
The amount is 0.5 to 2.5 mol, especially 0.8 to 1.2 mol per mol.
If it exceeds 2.5 moles, the reaction rate will be low, and the amount of by-products such as phenol will increase in the filtrate after the reaction and the degree of polymerization will not increase. If it is less than 0.5 mol, the reaction rate is too fast to obtain a sufficiently high molecular weight product.

In the case of the one-step reaction at a constant temperature, the cooling of the gas phase portion during the reaction is preferably performed from the start of the reaction, but it must be performed at least during the temperature increase of 250 ° C. or less. In the multi-stage reaction, it is preferable to perform cooling from the first-stage reaction, but it is preferable to perform cooling at the latest after the completion of the first-stage reaction. The degree of the cooling effect is usually the most suitable index of the pressure in the reactor. The absolute value of the pressure varies depending on the characteristics of the reaction vessel, the stirring state, the water content in the system, the molar ratio of the dihalo aromatic compound to the alkali metal sulfide, and the like. However, when the pressure in the reaction vessel is reduced as compared with the case where the reaction vessel is not cooled under the same reaction conditions, the amount of the reflux liquid increases, which means that the temperature at the gas-liquid interface of the reaction solution decreases. It is considered that the relative degree of decrease indicates the degree of separation between a layer having a high water content and a layer having no water content. Therefore, it is preferable to perform cooling to such an extent that the internal pressure of the reaction vessel is lower than that in the case where no cooling is performed. The degree of cooling can be appropriately set by those skilled in the art according to the equipment used, operating conditions, and the like.

The organic amide solvent used here is PA
Known for S-polymerization, such as N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylcaprolactam, etc., and mixtures thereof can be used, with N-methylpyrrolidone being preferred . They all have a lower vapor pressure than water. Alkali metal sulfides are also known, for example lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide,
Cesium sulfide and mixtures thereof. These hydrates and aqueous solutions may be used. Hydrosulfides and hydrates corresponding to these can be used after being neutralized with the corresponding hydroxides. Inexpensive sodium sulfide is preferred.

The dihalo aromatic compound is, for example, Japanese Patent Publication No.
It can be selected from those described in JP-A-5-3368, but is preferably p-dichlorobenzene. Further, a copolymer can be obtained by using one or more kinds of para-, meta- or ortho-dihalides of diphenyl ether, diphenyl sulfone or biphenyl in a small amount (20 mol% or less). For example, m-dichlorobenzene, o-dichlorobenzene,
p, p'-dichlorodiphenyl ether, m, p'-dichlorodiphenyl ether, m, m'-dichlorodiphenyl ether, p, p'-dichlorodiphenylsulfone, m, p'-dichlorodiphenylsulfone, m, m '
-Dichlorodiphenyl sulfone, p, p'-dichlorobiphenyl, m, p'-dichlorobiphenyl, m, m'-
Dichlorobiphenyl.

In order to increase the molecular weight of PAS,
It is also possible to use the polyhaloaromatic compound in a concentration of preferably 5 mol% or less based on the dihaloaromatic compound.
The polyhaloaromatic compound is a compound having three or more halogen substituents in one molecule, such as 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene,
1,3,5-trichlorobenzene, 1,3-dichloro-
5-bromobenzene, 2,4,6-trichlorotoluene, 1,2,3,5-tetrabromobenzene, hexachlorobenzene, 1,3,5-trichloro-2,4,6-
Trimethylbenzene, 2,2 ', 4,4'-tetrachlorobiphenyl, 2,2', 6,6'-tetrabromo-
3,3 ', 5,5'-tetramethylbiphenyl, 1,
2,3,4-tetrachloronaphthalene, 1,2,4-tribromo-6-methylnaphthalene and the like and mixtures thereof are mentioned, 1,2,4-trichlorobenzene, 1,
3,5-trichlorobenzene is preferred.

Further, at the latter stage of the reaction in the polymerization step of PAS, for example, when the reaction rate of the dihaloaromatic compound in the reaction system is preferably 90% or more, particularly preferably 95% or more, an end capping agent such as polyhalogen is used. Aromatic compounds,
Alkaline earth metal salt, its hydroxide or its oxide,
Alternatively, a zinc compound or the like can be charged, and 0.001 to 0.1 mol can be preferably added to 1 mol of the alkali metal sulfide.

As the polyhaloaromatic compound, the same ones as described above can be used. Examples of the alkaline earth metal salt, its hydroxide or its oxide include, for example, calcium chloride, calcium hydroxide, calcium oxide, magnesium hydroxide, calcium acetate, barium hydroxide and the like, and as a zinc compound. Examples include zinc chloride, zinc acetate, zinc sulfate, zinc sulfide, and the like. As an example,
When calcium chloride is used, PAS-SX
It is believed that the terminus (X represents an alkali metal) can be converted to the -SCaS- and -SCaCl forms. By taking such a form, it is thought that it affects the deterioration of the hue of PAS-by decreasing the SX terminal,
The hue of AS can be improved.

The PAS thus obtained can be separated from by-products by post-treatment methods known to those skilled in the art.

For washing with water to be carried out as a post-treatment of PAS, the following method can be preferably used.

That is, the washing with water is carried out by filtering the polymerized slurry produced in the PAS manufacturing step and then dispersing the filter cake in water. For example, the PAS polymerization slurry obtained as described above is filtered to obtain a PAS cake containing only a small amount of solvent. The PAS cake is put into water, preferably 1 to 5 times by weight, stirred and mixed at room temperature to 90 ° C. for preferably 5 minutes to 10 hours, and then filtered. The stirring and mixing and filtration operations are preferably repeated 2 to 10 times to remove the solvent and by-product salts attached to the PAS, thereby completing the water washing.

Further, it is preferable to treat the separated PAS with an acid. The acid treatment is preferably carried out at a temperature of 100 ° C. or lower, particularly preferably at room temperature to 80 ° C.
If the temperature exceeds the above upper limit, the PAS molecular weight after the acid treatment decreases, which is not preferable. The pH of the acid solution used for the acid treatment is preferably 3.5 to 6.0, particularly preferably 4.0 to 5.5. By adopting this pH, most of the -SX (X represents an alkali metal) terminal in PAS that is the object to be treated can be converted to the -SH terminal. If the pH is lower than the above range, the amount of the acid used is large and the cost is high. If the pH is higher than the above range, the removal of the alkali metal terminal from the PAS becomes insufficient. The time required for the acid treatment depends on the acid treatment temperature and the concentration of the acid solution,
It is preferably at least 5 minutes, particularly preferably at least 10 minutes. If it is less than the above, the -SX end in PAS cannot be sufficiently converted to the -SH end, which is not preferable. In the above acid treatment,
For example, acetic acid, formic acid, oxalic acid, phthalic acid, hydrochloric acid, phosphoric acid, sulfuric acid, sulfurous acid, nitric acid, boric acid, silicic acid, carbonic acid, propionic acid and the like are used, and acetic acid is particularly preferable. By performing the treatment, the alkali metal, such as sodium, which is an impurity in PAS can be reduced, and the hue of PAS can be improved.

Further, the following post-treatment method can be used instead of the above-mentioned post-treatment method.

That is, after filtering the PAS slurry obtained in the above polymerization step, the solvent-containing filter cake obtained is heated at a temperature of 150 to 250 ° C. in a non-oxidizing gas atmosphere to remove the solvent, and then water. This is a method of cleaning.

For example, the PAS obtained as described above
The slurry is filtered to give a PAS cake with solvent. The PAS cake is then helium, argon, hydrogen,
Heated in a stream of non-oxidizing gas such as nitrogen, preferably in a stream of nitrogen gas at a temperature of 150 to 250 ° C., preferably 180 to 230 ° C., preferably 0.5 to 20 hours, particularly preferably 1 to 10 hours. It The heating is preferably normal pressure to
It is carried out under 3 atmospheres, particularly preferably under normal pressure. By performing the solvent removal by heating as described above, it is possible to increase the adhesive strength of PAS and simplify the steps such as water washing as compared with the conventional method of removing the solvent by water washing.
Moreover, since the recovery rate of the solvent can be remarkably improved, the productivity is high and the cost is advantageous.

The subsequent water washing can be performed according to a known method. Preferably, the water washing method described above is used. In any case, washing with water can be simplified.

Further, the PAS after washing with water may be subjected to an acid treatment in the same manner as described above.

The post-treatment method is the same as the above-mentioned end-blocked P.
It is preferably used for AS.

In the resin composition of the present invention, the component (A)
As for the compounding ratio of the component (B) and the component (B), the upper limit of the component (B) is 15 parts by weight, preferably 10 parts by weight, particularly preferably 5 parts by weight, and the lower limit is 0.01, based on 100 parts by weight of the component (A). Parts by weight, preferably 0.1 parts by weight, particularly preferably 0.5
Parts by weight. If it exceeds the above range, the melt viscosity V ₆ is increased, and if the component (B) is less than the above range, the hue cannot be improved.

The resin composition of the present invention contains conventional additives such as alumina, talc, mica, kaolin, clay, titanium oxide, calcium carbonate, calcium silicate, calcium phosphate and sulfuric acid as long as the object of the invention is not impaired. Granular, powdery or scaly ones such as calcium, magnesium carbonate, magnesium oxide, magnesium phosphate, silicon nitride, glass, hydrotalcite, zirconium oxide, or glass fiber, potassium titanate fiber, carbon fiber, mica ceramic fiber A fibrous material such as the above can be blended. Each of these inorganic fillers is
Alternatively, two or more kinds can be used in combination. These inorganic fillers may be those treated with a silane coupling agent or a titanate coupling agent. The compounding ratio of the filler is preferably 1 to 400 parts by weight, particularly preferably 10 to 2 parts by weight with respect to 100 parts by weight of PAS.
It is 00 parts by weight.

Further, if necessary, additives such as an antioxidant, a heat stabilizer, a lubricant, a release agent and a coloring agent may be added.

The method for producing the resin composition of the present invention is not particularly limited. For example, the above components may be premixed with a mixer such as a Henschel mixer in advance, and then melt-kneaded with a conventional device such as an extruder to form a composition, or further pelletized.

The resin composition of the present invention is molded into a desired shape by, for example, injection molding or compression molding, and a molded product particularly required to have a beautiful appearance, for example, electronic parts, home electric appliance parts, cameras, watches and the like. Used for precision machine parts, etc.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0041]

EXAMPLES In the examples, the melt viscosity V ₆ was 300 ° C. using a flow tester CFT-500C manufactured by Shimadzu Corporation,
It is a viscosity (poise) measured after holding for 6 minutes under a load of 20 kgf / cm ² and L / D = 10.

The autoclave Synthesis Example 1 4m ^3, flaky sodium sulfide (6
0.7 wt% Na ₂ S) 515.4 kg and N-methyl-
2-pyrrolidone (hereinafter sometimes abbreviated as NMP) 1
200 kg was charged. Liquid temperature 2 with stirring under nitrogen stream
The temperature was raised to 04 ° C. and 125.4 kg of water was distilled off.
Then, the autoclave was closed and cooled to 180 ° C., and 596.0 kg of p-dichlorobenzene (hereinafter sometimes abbreviated as p-DCB) and 400 kg of NMP were charged. 1 kg / cm at a liquid temperature of 150 ° C using nitrogen gas
^The temperature was increased by pressurizing to ² G. From the time when the liquid temperature reached 215 ° C., water was sprinkled with a water sprinkler attached outside the upper part of the autoclave to cool the upper part of the autoclave. Then, the temperature was raised to a liquid temperature of 260 ° C., and then the mixture was stirred at that temperature for 2 hours to proceed the reaction. Next, the temperature was lowered and the cooling at the top of the autoclave was stopped. During the cooling of the upper part of the autoclave, the liquid temperature was kept constant so as not to drop.

The obtained slurry is filtered by a conventional method,
Washing with warm water was repeated and drying was performed in a hot air circulation dryer at 130 ° C. for about 4 hours to obtain PPS having a white powdery linear structure. The melt viscosity V ₆ of the obtained PPS was 1140 poise.

The PPS was used in the following examples and comparative examples.

[0045]

Examples 1 to 4 and Comparative Examples 1 to 6 Silica and other additives used in Examples and Comparative Examples are as follows. <Silica>

[0046]

[Table 1] <Other additives (comparative components)>-Phosphorus compound: PEP36, trademark, manufactured by Asahi Denka Co., Ltd.-White pigment: Dry Color HS-D 921285,
Trademark, manufactured by Dainichiseika Co., Ltd. In each of the Examples and Comparative Examples, the components were mixed in the amounts (parts by weight) shown in Table 2 by using a Henschel mixer, and the melt viscosity V ₆ was measured. Regarding whiteness (hot press L value), a sample was prepared by similarly mixing with a Henschel mixer and then melt-kneading.

The melt viscosity V ₆ of the sample was measured using a flow tester CFT-500C manufactured by Shimadzu Corporation in the same manner as above.

The whiteness (hot press L value) was measured as follows. <Whiteness (hot press L value)> The sample was preheated at 320 ° C. for 1.5 minutes and then at 320 ° C. for 1.5 minutes, followed by 13
A disk-shaped plate was formed by pressure molding with a hot press at a pressure of 30 kg / cm ² at 0 ° C. for 1.5 minutes, and a disc-shaped plate was prepared using a colorimeter (Tokyo Denshoku Co., Ltd., Color
Ace).

The tensile strength was measured as follows. <Tensile Strength> In each of the Examples and Comparative Examples, the amount (parts by weight) of each component shown in Table 2 was further added to the glass fiber (3J961).
S, trademark, manufactured by Nitto Boseki Co., Ltd.) 67 parts by weight,
Mixed using a Henschel mixer. Then 25
Using a mmφ twin-screw extruder, the mixture was melt-kneaded at a barrel setting temperature of 300 ° C. and extruded to form pellets. Cylinder temperature 320 ℃, mold temperature 130 ℃ from the obtained pellets
A dumbbell piece according to ASTM D638 was produced by an injection molding machine set to. Using the dumbbell piece, AST
The tensile strength was measured according to MD638.

The above results are shown in Table 2.

[0051]

[Table 2] In Examples 1 to 5, (A) PPS was mixed with (B) silica. The whiteness was higher in all cases than in Comparative Example 6 in which only PPS containing no silica was blended. Neither the melt viscosity V ₆ nor the tensile strength was significantly changed. In Examples 1 to 4, the compounding amount of (B) silica was changed within the range of the present invention. It was found that the whiteness tends to increase as the blending amount of silica increases. In Comparative Example 4, V ₆ was slightly increased, but the effect of the present invention could be sufficiently achieved. Example 5
Is a modification of the silica of Example 2 with silica having a larger pore volume and average pore diameter within the scope of the present invention. The whiteness, V ₆ and tensile strength of the resin composition did not change significantly.

On the other hand, in Comparative Example 1, the compounding amount of silica exceeds the range of the present invention. Compared to Comparative Example 6 containing only PPS, whiteness was increased, but V ₆ was also significantly increased.
Also, a slight decrease in tensile strength was observed. Comparative Examples 2 and 3 both use silica whose pore volume and average pore diameter exceed the range of the present invention. Compared to Comparative Example 6, the increase of V ₆ was remarkable, and the tensile strength was slightly decreased. In Comparative Example 4, a phosphorus compound was blended in place of (B) silica. A decrease in V ₆ was observed as compared with Comparative Example 6, and the tensile strength was also decreased.
In addition, gas was generated during melt molding. Comparative Example 5
(B) A white pigment is blended instead of silica. As compared with Comparative Example 6, a remarkable decrease in V _{6 and} a decrease in tensile strength were observed. As described above, addition of silica, a phosphorus compound, or a white pigment having a larger pore volume and average pore diameter can increase the whiteness of the resin composition, but V
₆ and the change in tensile strength was also found to be large.

[0053]

INDUSTRIAL APPLICABILITY The present invention provides a PAS resin composition having improved whiteness without changing the original melt viscosity of PAS and without lowering mechanical strength such as tensile strength.

Claims (3)

[Claims] (A) Polyarylene sulfide 100
A polyarylene sulfide resin composition containing, by weight, (B) 0.01 to 15 parts by weight of silica having a pore volume of 1.00 ml / g or less and an average pore diameter of 100 Å or less. 2. The pore volume of (B) silica is 0.20 to
0.90 ml / g and an average pore diameter of 20 to 80
The resin composition according to claim 1, which is angstrom. 3. The average particle size of (B) silica is 1.0 to 10.
The resin composition according to claim 1, which has a thickness of μm.