JP3557015B2 - Polyarylene sulfide resin composition - Google Patents

Description

＜他の添加物（比較成分）＞
・リン化合物：ＰＥＰ３６、商標、旭電化株式会社製
・白色顔料：ドライカラー ＨＳ‐Ｄ ９２１２８５、商標、大日精化株式会社製
各実施例及び比較例とも、各成分を表２に示す量（重量部）でヘンシェルミキサーを使用して混合し、溶融粘度Ｖ_６ の測定に供した。白色度（ホットプレスＬ値）については、同じくヘンシェルミキサーで混合後、更に溶融混練して試料とした。
【００４７】
溶融粘度Ｖ_６ は、該試料を上記と同じく島津製作所製フローテスターＣＦＴ‐５００Ｃを用いて測定した。
【００４８】
白色度（ホットプレスＬ値）は下記の如く測定した。
＜白色度（ホットプレスＬ値）＞
上記試料を３２０℃で１．５分間予熱後、３２０℃で１．５分間、続けて１３０℃で１．５分間、３０ｋｇ／ｃｍ^２ の圧力でホットプレスにより加圧成形して円盤状プレートを作り、これについて、色彩色差計（東京電色株式会社製、Ｃｏｌｏｒ Ａｃｅ）を用いて測定した。
【００４９】
引張強度は、下記の如く測定した。
＜引張強度＞
各実施例及び比較例とも、表２に示す量（重量部）の各成分に、更にガラス繊維（３Ｊ９６１Ｓ、商標、日東紡績株式会社製）６７重量部を加えて、ヘンシェルミキサーを使用して混合した。次いで、２５ｍｍφ二軸押出機を用いてバレル設定温度３００℃で溶融混練して押出し、ペレットを作成した。得られたペレットから、シリンダー温度３２０℃、金型温度１３０℃に設定した射出成形機により、ＡＳＴＭ Ｄ６３８に従うダンベル片を作成した。該ダンベル片を用い、ＡＳＴＭ Ｄ６３８に準拠して引張強度を測定した。
【００５０】
以上の結果を表２に示す。
【００５１】
【表２】

実施例１〜５は、（Ａ）ＰＰＳに（Ｂ）シリカを配合したものである。シリカを配合していないＰＰＳのみの比較例６に比べて、白色度はいずれも高くなった。溶融粘度Ｖ_６ 及び引張強度はいずれも大きな変化は認められなかった。実施例１〜４は、（Ｂ）シリカの配合量を本発明の範囲内で変化させたものである。シリカの配合量を増加すると、白色度が増加する傾向にあることが分かった。比較例４では、Ｖ_６ の多少の増加が見られたが、本発明の効果を十分に達成し得るものであった。実施例５は、実施例２のシリカを本発明の範囲内でより大きな細孔容積及び平均細孔径を持つシリカに変えたものである。樹脂組成物の白色度、Ｖ_６ 及び引張強度はいずれも大きな変化はなかった。
【００５２】
一方、比較例１は、シリカの配合量が本発明の範囲を超えたものである。ＰＰＳのみの比較例６に比べて、白色度は増加したが、Ｖ_６ も著しく増加した。また、引張強度の少しの低下も見られた。比較例２及び３は、いずれも細孔容積及び平均細孔径において、本発明の範囲を超えるシリカを使用したものである。比較例６に比べて、いずれもＶ_６ の増加が著しく、また、引張強度の少しの低下も見られた。比較例４は、（Ｂ）シリカに代えて、リン化合物を配合したものである。比較例６と比べてＶ_６ の減少が見られ、引張強度も低下した。また、溶融成形時にガスの発生があった。比較例５は、（Ｂ）シリカに代えて、白色顔料を配合したものである。比較例６に比べて、著しいＶ_６ の減少及び引張強度の低下が見られた。このように、細孔容積及び平均細孔径のより大きいシリカ、リン化合物又は白色顔料の添加では、樹脂組成物の白色度を高めることはできるが、Ｖ_６ 及び引張強度の変化も大きいことが分かった。
【００５３】
【発明の効果】
本発明は、ＰＡＳ本来の溶融粘度を変化させることなく、引張強度等の機械的強度を低下させることもなく、白色度の向上したＰＡＳ樹脂組成物を提供する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyarylene sulfide resin composition, and more particularly, to a polyarylene sulfide resin composition having excellent hue.
[0002]
[Prior art]
Conventionally, various means have been employed to improve the hue of polyarylene sulfide (hereinafter sometimes abbreviated as PAS) and to reduce discoloration.
[0003]
For example, a method is known in which a halo-substituted organic compound such as a polyhalo aromatic compound is added to a polymerization system at a later stage of polymerization to stabilize polymer chain terminals (JP-A-62-97821). However, it has been found that the melt viscosity tends to be low. It has been proposed to mix a white pigment into a polyphenylene sulfide (hereinafter abbreviated as PPS) resin to whiten it, and to compensate for the decrease in mechanical strength due to the addition of the white pigment by adding an epoxy resin ( JP-A-60-8359). However, this results in high costs. Titanium oxide and zinc sulfide are described as white pigments. Silica is mentioned in the illustration of the optional reinforcement, but there is no further description of silica. In addition, in a composition comprising 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). Publication). However, there are drawbacks that the melt viscosity is reduced during melt molding and a decomposition gas is generated.
[0004]
[Problems to be solved by the invention]
The present invention provides a PAS resin composition having improved whiteness without changing the inherent melt viscosity of PAS and without reducing mechanical strength such as tensile strength.
[0005]
[Means for Solving the Problems]
The present inventors have conducted various studies in order to solve the above problems. As a result, it has been found that all of the above-mentioned problems can be solved by blending silica having the following predetermined properties with PAS, and the present invention has been completed.
[0006]
That is, the present invention
(1) A poly (A) containing 100 parts by weight of polyarylene sulfide and (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. It is an arylene sulfide resin composition.
[0007]
As a preferred embodiment,
(2) The resin composition according to the above (1), wherein (B) silica has a pore volume of 0.20 to 0.90 ml / g and an average pore diameter of 20 to 80 Å.
(3) The resin composition according to the above (1) or (2), wherein the average particle size of the silica (B) is 1.0 to 10 μm.
Can be mentioned.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The pore volume of the silica (B) used in the present invention has an upper limit of 1.00 ml / g, preferably 0.90 ml / g, particularly preferably 0.85 ml / g, and a lower limit of preferably 0.20 ml / g. g, particularly preferably 0.30 ml / g. Exceed the upper limit is not preferable because the melt viscosity V ₆ of the PAS resin composition is increased. (B) The average pore size of the silica has an upper limit of 100 angstroms, preferably 80 angstroms, particularly preferably 70 angstroms, and a lower limit of preferably 20 angstroms, particularly preferably 25 angstroms. Exceed the upper limit, it increased melt viscosity V ₆ of the PAS resin composition, workability unfavorably deteriorated. 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.
[0009]
The upper limit of the average particle size of the silica (B) 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 a Coal counter method (D ₅₀ ). When the average particle size exceeds the upper limit, not only the dispersibility is deteriorated, but also the effects of the present invention cannot be obtained. Is less than the above lower limit, causing an increase in melt viscosity V ₆ of the PAS resin composition. In the particle size distribution, particles having a particle size of 8 μm or less are preferably 90% by weight or more, and particularly preferably particles having a particle size of 9 μm or less are 95% by weight or more.
[0010]
(B) The silica is not particularly limited as long as it has the above properties. Preferably, colloidal silica is used.For example, high-purity silica sand is used as a raw material, and sodium silicate and sulfuric acid are mixed to form 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 of making it perform can be used. Commercially available products include, for example, Cycilia 730, Cycilia 740, Cycilia 770, Cycilia 530, Cycilia 540, and Cysyria 550 (all trademarks) manufactured by Fuji Silysia Limited.
[0011]
The component (A) PAS used in the resin composition of the present invention is a known polymer having an arylene sulfide repeating unit, and is particularly preferably polyphenylene sulfide.
[0012]
The method for producing (A) PAS of the present invention is not particularly limited. For example, a method of reacting a dihalo aromatic compound with an alkali metal sulfide in an organic amide solvent (Japanese Patent Publication No. 45-3368) can be used.
[0013]
Preferably, a method is used in which the gas phase portion of the reaction vessel is cooled and a part of the gas phase is refluxed to a liquid phase (Japanese Patent Application Laid-Open No. 5-222196). The PAS produced by this method is a relatively high molecular weight PAS having a substantially linear structure, and is preferable because it has excellent mechanical strength such as tensile strength. That is, the method is a method for producing a PAS by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent, wherein the gas phase in the reaction vessel is cooled by cooling the gas phase portion of the reaction vessel. A method for producing a PAS, comprising condensing a part and refluxing the liquid in a liquid phase.
[0014]
In the PAS production method, the refluxed liquid has a higher water content than the liquid phase bulk due to the vapor pressure difference between water and the amide solvent. The high water content reflux liquid forms a high water content layer above the reaction solution. As a result, the layer contains a large amount of residual alkali metal sulfide (eg, Na ₂ S), alkali metal halide (eg, NaCl), oligomers, and the like. In the conventional method, at a high temperature of 230 ° C. or higher, in a state where the produced PAS and the raw materials such as Na ₂ S and by-products are uniformly mixed, not only a high molecular weight PAS cannot be obtained, but The depolymerized PAS 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 reflux liquid rich in water 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 to the effect of the above phenomenon, and a high molecular weight PAS can be obtained by various effects caused by cooling the gas phase portion.
[0015]
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, if the operation of adding water is performed, 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.
[0016]
Cooling of the gas phase portion of the reaction vessel can be performed 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 portion in a reaction vessel, a method of flowing a cooling medium through an external coil or a jacket wrapped around an upper portion of the outside of the reaction vessel, and using a reflux condenser installed at the top of the reaction vessel Methods, such as spraying water or blowing gas (air, nitrogen, etc.) on the upper part of the outside of the reaction vessel, are conceivable. However, any method that results in increasing the amount of reflux in the vessel can be considered. 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, the water / amide-based solvent mixture condensed on the reactor wall enters the liquid phase along the reactor wall. The water-rich mixture therefore accumulates in the upper part of the liquid phase, keeping the water content relatively high. In the case of internal cooling, the mixture condensed on the cooling surface likewise travels on the cooling device surface or on the reactor wall and enters the liquid phase.
[0017]
On the other hand, the temperature of the liquid phase bulk is kept at a predetermined constant temperature or controlled according to a predetermined temperature profile. When the temperature is kept constant, it is preferable to carry out the reaction at a temperature of 230 to 275 ° C for 0.1 to 20 hours. More preferably, it is at a temperature of 240 to 265 ° C for 1 to 6 hours. In order to obtain a higher molecular weight PAS, it is preferable to use a reaction temperature profile of two or more steps. When performing this two-step operation, the first step is preferably performed at a temperature of 195 to 240 ° C. If the temperature is low, the reaction rate is too low and is not practical. If the temperature is higher than 240 ° C., the reaction rate is too high, so that not only PAS having a sufficiently high molecular weight cannot be obtained, but also the side reaction rate significantly increases. The first stage is preferably terminated when the residual ratio of the dihalo aromatic compound in the polymerization reaction system is 1 mol% to 40 mol% and the molecular weight is in the range of 3,000 to 20,000. More preferably, the residual ratio of the dihaloaromatic 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. If the residual ratio exceeds 40 mol%, side reactions such as depolymerization tend to occur in the second stage reaction, while if it is less than 1 mol%, it is difficult to finally obtain a high molecular weight PAS. Thereafter, the temperature is raised, and the reaction in the final stage is preferably performed at a reaction temperature of 240 to 270 ° C. for 1 hour to 10 hours. If the temperature is low, it is not possible to obtain a PAS having a sufficiently high molecular weight, and if the temperature is higher than 270 ° C., side reactions such as depolymerization are liable to occur, making it difficult to obtain a high molecular weight product stably.
[0018]
As an actual operation, first, under an inert gas atmosphere, dehydration or water addition is performed as necessary so that the amount of water in the alkali metal sulfide in the amide solvent becomes a predetermined amount. The water content is preferably 0.5 to 2.5 mol, particularly 0.8 to 1.2 mol, per 1 mol of alkali metal sulfide. 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 the amount is less than 0.5 mol, the reaction rate is too high, and a product having a sufficient high molecular weight cannot be obtained.
[0019]
In the case of a one-stage reaction at a constant temperature, the cooling of the gas phase during the reaction is desirably performed from the start of the reaction, but must be performed at least during the temperature rise of 250 ° C. or lower. 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 at the middle of the temperature rise after 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 differs depending on the characteristics of the reaction vessel, the stirring state, the amount of water 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.
[0020]
The organic amide solvents used herein are known for PAS polymerization, such as N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylcaprolactam, and the like, and mixtures thereof. And N-methylpyrrolidone is 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 respectively corresponding to these can be used after being neutralized with the corresponding hydroxides. Inexpensive sodium sulfide is preferred.
[0021]
The dihalo aromatic compound can be selected from, for example, those described in JP-B-45-3368, but is preferably p-dichlorobenzene. In addition, a copolymer can be obtained using one or more kinds of paraphenyl, meta or ortho dihalo compounds of diphenyl ether, diphenyl sulfone or biphenyl in a small amount (20 mol% or less). For example, m-dichlorobenzene, o-dichlorobenzene, p, p'-dichlorodiphenylether, m, p'-dichlorodiphenylether, m, m'-dichlorodiphenylether, p, p'-dichlorodiphenylsulfone, m, p'- Dichlorodiphenylsulfone, m, m'-dichlorodiphenylsulfone, p, p'-dichlorobiphenyl, m, p'-dichlorobiphenyl and m, m'-dichlorobiphenyl.
[0022]
To increase the molecular weight of the PAS, the polyhaloaromatic compound can be used, preferably at a concentration of 5 mol% or less based on the dihaloaromatic compound. The polyhalo aromatic compound is a compound having three or more halogen substituents in one molecule, for example, 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, and 1,2,4-trichlorobenzene and 1,3,5-trichlorobenzene Masui.
[0023]
Further, at the latter stage of the reaction in the PAS polymerization step, for example, at the time when the reaction rate of the dihaloaromatic compound in the reaction system is preferably 90% or more, particularly preferably 95% or more, a terminal blocking agent such as a polyhaloaromatic compound , An alkaline earth metal salt, a hydroxide or oxide thereof, or a zinc compound, and the like, and preferably 0.001 to 0.1 mol can be added to 1 mol of the alkali metal sulfide.
[0024]
As the polyhaloaromatic compound, the same compounds as described above can be used. Examples of the alkaline earth metal salts, hydroxides or oxides thereof include, for example, calcium chloride, calcium hydroxide, calcium oxide, magnesium hydroxide, calcium acetate and barium hydroxide. Examples thereof include zinc chloride, zinc acetate, zinc sulfate, zinc sulfide and the like. As an example, when calcium chloride is used, it is believed that the -SX (X represents an alkali metal) end of the PAS can be changed to a form of -SCaS- and -SCaCl. By adopting this form, it is considered that the hue of the PAS is affected, and the -SX terminal can be reduced to improve the hue of the PAS.
[0025]
The PAS thus obtained can be separated from by-products by post-treatment methods known to those skilled in the art.
[0026]
As the water washing performed as a post-treatment of the PAS, preferably, the following method can be used.
[0027]
That is, the water washing is performed by filtering the polymerization slurry generated in the PAS production process and then dispersing the filter cake in water. For example, the polymerization slurry of PAS obtained as described above is filtered to obtain a PAS cake containing little solvent. The PAS cake is poured into water, preferably 1 to 5 times by weight, and stirred and mixed at room temperature to 90 ° C., preferably for 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.
[0028]
Further, it is preferable to subject the separated PAS to an acid treatment. The acid treatment is preferably carried out at a temperature of 100 ° C. or lower, particularly preferably at a temperature of 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 the pH, most of -SX (X represents an alkali metal) terminal in PAS to be treated can be converted to -SH terminal. If the pH is lower than the above range, the amount of the acid used is large and the cost is high. The time required for the acid treatment depends on the acid treatment temperature and the concentration of the acid solution, but is preferably 5 minutes or more, particularly preferably 10 minutes or more. If the amount is less than the above, -SX terminal in PAS cannot be sufficiently converted to -SH terminal, which is not preferable. For the 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 preferred. By performing the treatment, an alkali metal such as sodium, which is an impurity in the PAS, can be reduced, and the hue of the PAS can be improved.
[0029]
Further, the following post-treatment method can be used in place of the above-mentioned post-treatment method.
[0030]
That is, after filtering the PAS slurry obtained in the above polymerization step, the obtained solvent-containing filter cake is heated at a temperature of 150 to 250 ° C. in a non-oxidizing gas atmosphere to remove the solvent, and then subjected to water washing. Is the way.
[0031]
For example, the PAS slurry obtained as described above is filtered to obtain a PAS cake containing a solvent. Next, the PAS cake is heated in a non-oxidizing gas stream of helium, argon, hydrogen, nitrogen or the like, preferably in a nitrogen gas stream, at a temperature of 150 to 250 ° C., preferably 180 to 230 ° C., preferably 0.5 to 250 ° C. The heating is carried out for up to 20 hours, particularly preferably 1 to 10 hours. The heating is preferably performed at normal pressure to 3 atm, particularly preferably at normal pressure. By performing the above-mentioned solvent removal by heating, the adhesive strength of the PAS can be increased, and compared to the conventional method of removing the solvent by water washing, steps such as water washing can be simplified, and the solvent can be recovered. Since the rate can be significantly improved, the productivity is high and the cost is advantageous.
[0032]
The subsequent water washing can be performed according to a known method. Preferably, the water washing method described above is used. In any case, the water washing can be simplified.
[0033]
Further, the PAS after the water washing can be subjected to an acid treatment in the same manner as described above.
[0034]
This post-treatment method is preferably used for PAS having the above-mentioned end capping.
[0035]
In the resin composition of the present invention, the upper limit of (B) is 15 parts by weight, preferably 10 parts by weight, particularly preferably 100 parts by weight of (A) with respect to 100 parts by weight of (A). Is 5 parts by weight, and the lower limit is 0.01 part by weight, preferably 0.1 part by weight, particularly preferably 0.5 part by weight. Beyond these ranges, causes an increase in melt viscosity V _6, is less than the component (B) is within the above range, it is impossible to improve the hue.
[0036]
The resin composition of the present invention includes conventional additives, for example, alumina, talc, mica, kaolin, clay, titanium oxide, calcium carbonate, calcium silicate, calcium phosphate, calcium sulfate, and carbonate, as long as the object of the invention is not impaired. Magnesium, magnesium oxide, magnesium phosphate, silicon nitride, glass, hydrotalcite, zirconium oxide, etc. in granular, powdery or flaky form, or glass fiber, potassium titanate fiber, carbon fiber, mica ceramic fiber, etc. Can be blended. These inorganic fillers can be used alone or in combination of two or more. These inorganic fillers may be those treated with a silane coupling agent or a titanate coupling agent. The mixing ratio of the filler is preferably 1 to 400 parts by weight, particularly preferably 10 to 200 parts by weight, based on 100 parts by weight of PAS.
[0037]
Further, if necessary, additives such as an antioxidant, a heat stabilizer, a lubricant, a release agent, and a coloring agent may be added.
[0038]
The method for producing the resin composition of the present invention is not particularly limited. For example, the above components can be preliminarily mixed with a mixer such as a Henschel mixer, and then melt-kneaded with a conventional device such as an extruder to form a composition or pelletized.
[0039]
The resin composition of the present invention is molded into a desired shape by, for example, injection molding or compression molding, and in particular, molded articles requiring beautiful appearance, such as electronic parts, home electric parts, or precision machines such as cameras and watches. Used for parts, etc.
[0040]
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]
【Example】
In embodiments, a viscosity measured after holding the melt viscosity _{V 6} is 300 ° C. using a Shimadzu flow tester CFT-500C, a load of ^{20kgf / cm 2, L / D} = 10 6 min (poise).
[0042]
Synthesis Example 1
Autoclave 4m ^3, (may be abbreviated as NMP in the following) flaky sodium sulfide (60.7 _wt% Na 2 S) _515.4kg and N- methyl-2-pyrrolidone were charged 1200 kg. The solution was heated to a liquid temperature of 204 ° C. while stirring under a nitrogen stream to distill 125.4 kg of water. Thereafter, the autoclave was sealed 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. At a liquid temperature of 150 ° C., the pressure was increased to 1 kg / cm ² G using nitrogen gas, and the temperature was raised. When the liquid temperature reached 215 ° C., water was sprinkled with a sprinkler attached outside the upper part of the autoclave to cool the upper part of the autoclave. Thereafter, the temperature was raised to 260 ° C. by continuing to raise the temperature, and then the mixture was stirred at this temperature for 2 hours to advance the reaction. Next, the temperature was lowered and the cooling at the top of the autoclave was stopped. During cooling of the upper part of the autoclave, the liquid temperature was kept constant so as not to drop.
[0043]
The obtained slurry was repeatedly filtered and washed with warm water in a usual manner, and dried at 130 ° C. for about 4 hours in a circulating hot air drier to obtain PPS having a white powdery linear structure. The melt viscosity _{V 6} of the obtained PPS was 1140 poise.
[0044]
The PPS was used in the following Examples and Comparative Examples.
[0045]
Examples 1-4 and Comparative Examples 1-6
The silica and other additives used in the 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 Dainichi Seika Co., Ltd. In each of the examples and comparative examples, the components shown in Table 2 were used in amounts (weight). in parts) were mixed using a Henschel mixer, and subjected to measurement of melt viscosity V _6. With respect to the whiteness (hot press L value), the mixture was similarly mixed with a Henschel mixer and further melt-kneaded to obtain a sample.
[0047]
The melt viscosity _{V 6} is the sample was measured using a similarly manufactured by Shimadzu Flow Tester CFT-500C and above.
[0048]
The whiteness (hot press L value) was measured as follows.
<Whiteness (hot press L value)>
After preheating the above sample at 320 ° C. for 1.5 minutes, the disc-shaped plate was formed by pressing with a hot press at a pressure of 30 kg / cm ² at 320 ° C. for 1.5 minutes, then at 130 ° C. for 1.5 minutes. This was measured using a colorimeter (Color Ace, manufactured by Tokyo Denshoku Co., Ltd.).
[0049]
The tensile strength was measured as described below.
<Tensile strength>
In each of the examples and comparative examples, 67 parts by weight of glass fiber (3J961S, trademark, manufactured by Nitto Boseki Co., Ltd.) was further added to the components (parts by weight) shown in Table 2 and mixed using a Henschel mixer. did. Next, the mixture was melt-kneaded at a barrel setting temperature of 300 ° C. and extruded using a 25 mmφ twin-screw extruder to produce pellets. From the obtained pellets, dumbbell pieces according to ASTM D638 were prepared by an injection molding machine set at a cylinder temperature of 320 ° C and a mold temperature of 130 ° C. Using the dumbbell pieces, the tensile strength was measured according to ASTM D638.
[0050]
Table 2 shows the above results.
[0051]
[Table 2]

In Examples 1 to 5, (B) silica was blended with (A) PPS. The whiteness was higher than that of Comparative Example 6 containing only PPS containing no silica. The melt viscosity V ₆ and tensile strength major changes both were observed. In Examples 1 to 4, (B) the amount of silica was changed within the range of the present invention. It was found that increasing the amount of silica increased the whiteness. In Comparative Example 4, it was observed a slight increase in V _6, was achieved the effect of the present invention can be achieved sufficiently. Example 5 is obtained by replacing the silica of Example 2 with silica having a larger pore volume and a larger average pore diameter within the scope of the present invention. Whiteness of the resin composition, V ₆ and the tensile strength was not significantly changed either.
[0052]
On the other hand, in Comparative Example 1, the compounding amount of silica exceeded the range of the present invention. Compared to Comparative Example 6 PPS alone, although whiteness was increased, V ₆ was also significantly increased. Also, a slight decrease in tensile strength was observed. Comparative Examples 2 and 3 both use silica that exceeds the scope of the present invention in pore volume and average pore diameter. Compared to Comparative Example 6, both the increase in V ₆ significantly, also seen any decrease in tensile strength. In Comparative Example 4, a phosphorus compound was blended in place of (B) silica. Reduction of V ₆ as compared with Comparative Example 6 was observed, the tensile strength was reduced. In addition, gas was generated during melt molding. In Comparative Example 5, a white pigment was blended in place of (B) silica. Compared to Comparative Example 6, decrease in the reduction and tensile strength of significant V ₆ was observed. Thus, the pore volume and average pore diameter greater than silica, with the addition of the phosphorus compound or a white pigment is to increase the whiteness of the resin composition can, found that the greater the change in V ₆ and tensile strength Was.
[0053]
【The invention's effect】
The present invention provides a PAS resin composition having improved whiteness without changing the original melt viscosity of PAS and without reducing mechanical strength such as tensile strength.

Claims (3)

A polyarylene sulfide resin comprising (A) 100 parts by weight of polyarylene sulfide and (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. Composition. 2. The resin composition according to claim 1, wherein (B) the silica has a pore volume of 0.20 to 0.90 ml / g and an average pore diameter of 20 to 80 Å. 3. The resin composition according to claim 1, wherein (B) the silica has an average particle size of 1.0 to 10 [mu] m.