Polyarylene sulfide resin composition and molded article

Abstract

Provided is a polyarylene sulfide resin composition prepared by blending 100 parts by weight of (A) polyarylene sulfide with 10 to 200 parts by weight of (B) glass fibers, in which the polyarylene sulfide (A) has such a property that, in a molecular weight distribution curve, the cumulative integrated value at a molecular weight of 4,000 is 48 to 53 inclusive when the cumulative integrated value in the range from a molecular weight of 100 to a molecular weight of 10,000 is defined as 100, and a rate of change represented by the formula: MFR2 / MFR1 is 0.085 or less in which MFR1 represents the melt flow rate of the polyarylene sulfide and MFR2 represents the melt flow rate of a product prepared by mixing the polyarylene sulfide with an epoxy silane coupling agent at a weight-based ratio of 100:1 and then heating the resultant mixture at 315.5°C for 5 minutes.　It is possible to provide a polyarylene sulfide resin composition having excellent mechanical strength and wet heat resistance and having improved mold processability.

Description

[Technical Field]

[0001] This invention relates to a polyarylene sulfide resin composition that exhibits excellent mechanical strength and moisture and heat resistance, as well as improved moldability. [Background technology]

[0002] Polyarylene sulfide (sometimes abbreviated as PAS) is a high-heat-resistant super engineering plastic that excels in mechanical strength, rigidity, flame retardancy, chemical resistance, electrical properties, and dimensional stability, and is therefore widely used in various electrical and electronic components, home appliance components, automotive parts, and machine parts.

[0003] On the other hand, the performance requirements for PAS (Power Application System) have become more sophisticated year by year, and along with further improvements in mechanical strength and durability, excellent melt-molding processability is now required.

[0004] Patent Document 1 discloses a resin composition containing a polyarylene sulfide with high reactivity with epoxysilane, a silane compound having an epoxy group, and a filler.

[0005] Patent Document 2 discloses a polyarylene sulfide resin composition comprising a polyarylene sulfide resin, glass fibers, and an alkoxysilane compound having an amino group. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-256517 [Patent Document 2] International Publication No. 2018 / 180591 [Overview of the initiative] [Problems that the invention aims to solve]

[0007] In Patent Document 1, although the mechanical properties such as bending strength and impact strength were improved by using polyarylene sulfide in which 1.0% γ-glycidoxypropyltrimethoxysilane was added and the melt viscosity increase after kneading at 320°C for 5 minutes was in the range of 4.0 to 12.0, the improvement effect was still insufficient, and there were also problems with poor moldability, such as excessive mold contamination.

[0008] In Patent Document 2, by blending an alkoxysilane compound having an amino group with an acid-treated polyarylene sulfide resin and setting the exothermic peak temperature (Tmc) associated with crystallization to 195°C to 225°C, the hydrostatic fracture strength is improved, but the resistance to humid heat is not very high, and there is a problem that the melt viscosity tends to increase during molding, and the thin-wall molding processability is also poor. [Means for solving the problem]

[0009] To solve the above problems, the present invention has the following configuration. (1) A polyarylene sulfide resin composition comprising 10 to 200 parts by weight of (B) glass fiber to 100 parts by weight of (A) polyarylene sulfide, wherein the (A) polyarylene sulfide has a cumulative integral value of 48 or more and 53 or less at a molecular weight of 4,000 when the cumulative integral value from molecular weight 100 to 10,000 in the molecular weight distribution curve is set to 100, and the melt flow rate of the (A) polyarylene sulfide is MFR1, and the melt flow rate after mixing the (A) polyarylene sulfide and an epoxy silane coupling agent in a weight ratio of 100:1 and heating at 315.5°C for 5 minutes is MFR2, wherein the rate of change expressed as MFR2 / MFR1 is 0.085 or less. (2) The polyarylene sulfide resin composition according to (1), wherein the polyarylene sulfide resin composition is further compounded with (A) 100 parts by weight of polyarylene sulfide and (C) 10 to 250 parts by weight of a non-fibrous inorganic filler. (3) The polyarylene sulfide resin composition according to (1) or (2), wherein the polyarylene sulfide resin composition is further compounded with (A) 100 parts by weight of polyarylene sulfide and (D) 0.1 to 10 parts by weight of an organosilane coupling agent having at least one functional group selected from the group consisting of epoxy groups, amino groups and isocyanate groups. (4) The polyarylene sulfide resin composition according to (3), wherein the functional group of the organosilane coupling agent (D) is an amino group or an isocyanate group. (5) A polyarylene sulfide resin composition according to any one of (1) to (4), wherein the (A) polyarylene sulfide has a crosslinked structure. (6) The polyarylene sulfide resin composition according to (5), wherein the (A) polyarylene sulfide having a crosslinked structure is dissolved in 20 times its weight of 1-chloronaphthalene at 250°C for 5 minutes, and the amount of residue when filtered by hot pressure through a PTFE membrane filter with a pore size of 1 μm is 4.0% by weight or less. (7) A molded article comprising a polyarylene sulfide resin composition as described in any of (1) to (6). (8) The molded product according to (7), wherein the molded product is a fluid piping component through which a fluid mainly composed of water flows. [Effects of the Invention]

[0010] According to the present invention, a polyarylene sulfide resin composition can be provided that exhibits excellent mechanical strength and heat and humidity resistance of molded products, as well as low gas generation during molding and excellent fluidity, thereby improving moldability. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described in detail below.

[0012] (A) Polyarylene sulfide (1) Chemical structure and molecular weight The polyarylene sulfide in the present invention is a homopolymer or copolymer having a repeating unit of the formula -(Ar-S)- as a main constituent unit. Examples of Ar include units represented by the following formula (A) to formula (L), etc., and formula (A) is particularly preferred.

[0013]

Chemical formula

[0014] (R1 and R2 are substituents selected from a hydrogen atom, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different). As long as this repeating unit is the main constituent unit, a small amount of branched units or crosslinked units represented by the following formula (M) to formula (P), etc., can be included. The copolymerization amount of these branched units or crosslinked units is preferably in the range of 0 mol% or more and 1 mol% or less per 1 mol of the -(Ar-S)- unit.

[0015]

Chemical formula

[0016] Also, the PAS in the present invention may be a random copolymer, a block copolymer, or a mixture thereof containing the above repeating unit. Representative examples thereof include polyarylene sulfide, polyarylene sulfide sulfone, polyarylene sulfide ketone, random copolymers, block copolymers, and mixtures thereof of these. Particularly preferred PAS includes polyarylene sulfide, polyarylene sulfide sulfone, and polyarylene sulfide ketone containing 90 mol% or more of a p-arylene unit represented by the following formula as a main constituent unit of the polymer.

[0017]

Chemical formula

[0018] While there are no particular restrictions on the molecular weight of these PAS, a typical weight-average molecular weight (Mw) of PAS can range from 5,000 to 1,000,000, preferably from 7,500 to 500,000, and more preferably from 10,000 to 100,000. In this invention, the molecular weight of PAS is measured by gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). Regarding melt viscosity, which is known to correlate with weight-average molecular weight (Mw), a range of 0.1 to 1,000 Pa·s (300°C, shear rate 1,000 / sec) can be exemplified from the above-mentioned preferred Mw, with a range of 0.1 to 500 Pa·s being preferred. PAS with molecular weight and melt viscosity within the above preferred ranges exhibits excellent moldability and tend to be favorably used in many applications.

[0019] The method for producing PAS used in the present invention is described below. First, the sulfidating agent, dihalogenated aromatic compound, organic polar solvent, and water present in the system will be explained.

[0020] (2) Sulfide agents The sulfidating agent used in the present invention can be any agent capable of introducing a sulfide bond to a dihalogenated aromatic compound, such as alkali metal sulfides and alkali metal hydrosulfides. Specific examples of alkali metal sulfides include sodium sulfide, potassium sulfide, lithium sulfide, rubidium sulfide, and cesium sulfide, with sodium sulfide being preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or in anhydrous form.

[0021] Specific examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide, with sodium hydroxide being the most preferred. These alkali metal hydroxides can be used as hydrates, aqueous mixtures, or in anhydrous form.

[0022] It is also possible to use alkali metal hydroxides and / or alkaline earth metal hydroxides in combination with sulfidating agents. Specific examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide, while specific examples of alkaline earth metal hydroxides include calcium hydroxide, strontium hydroxide, and barium hydroxide, with sodium hydroxide being particularly preferred.

[0023] When using alkali metal hydroxide as a sulfidating agent, it is particularly preferable to use alkali metal hydroxide simultaneously. The amount used is preferably 0.95 moles to 1.20 moles per mole of alkali metal hydroxide, more preferably 1.00 moles to 1.15 moles, and even more preferably 1.005 moles to 1.100 moles. The sulfidating agent can be introduced into the system at any time, but it is preferable to introduce it before the dehydration operation described later.

[0024] (3) Dihalogenated aromatic compounds The dihalogenated aromatic compounds used in this invention are compounds that have an aromatic ring, contain two halogen atoms in one molecule, and have a molecular weight of 1,000 or less. Specific examples include dihalogenated benzenes such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, p-dibromobenzene, m-dibromobenzene, o-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene; dihalogenated benzenes that also contain substituents other than halogens, such as 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, and 3,5-dichlorobenzoic acid; and dihalogenated aromatic compounds such as 1,4-dichloronaphthalene, 1,5-dichloronaphthalene, 4,4'-dichlorobiphenyl, 4,4'-dichlorodiphenyl ether, 4,4'-dichlorodiphenyl sulfone, and 4,4'-dichlorodiphenyl ketone. Among these, dihalogenated aromatic compounds with p-dihalogenated benzene, represented by p-dichlorobenzene, as the main component are preferred. Particularly preferred is a mixture containing 80 to 100 mol% of p-dichlorobenzene, and more preferably 90 to 100 mol%. It is also possible to use a combination of two or more different dihalogenated aromatic compounds to produce the PAS copolymer.

[0025] The amount of dihalogenated aromatic compound used is preferably 0.1 mole to 3 moles per mole of sulfur in the sulfidating agent, more preferably 0.5 mole to 2 moles, and even more preferably 0.9 mole to 1.2 moles. When the amount of dihalogenated aromatic compound used is within the above preferred range, the molecular weight of PAS can be easily controlled within the preferred range of the present invention, and a PAS with a low amount of chloroform extractable components can be obtained.

[0026] While the dihalogenated aromatic compounds can be introduced into the system at any time, it is preferable to introduce them after the dehydration process described later. Furthermore, in addition to adding the entire amount at once, other methods such as introducing them in stages are also possible.

[0027] (4) Organic polar solvents In this invention, an organic polar solvent is used as the reaction solvent, and among these, an organic amide solvent with high reaction stability is preferred. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphate triamide, dimethyl sulfone, and tetramethylene sulfoxide. Mixtures of these can also be used, but N-methyl-2-pyrrolidone is preferred.

[0028] In the present invention, the amount of organic polar solvent used in the reaction system is preferably 0.5 moles to 10 moles per mole of sulfur in the sulfidating agent, and more preferably 2 moles to 8 moles. When the amount of organic polar solvent is within the above preferred range, undesirable reactions are less likely to occur, and the degree of polymerization tends to increase. Here, the amount of organic polar solvent in the reaction system is the amount of organic polar solvent introduced into the reaction system minus the amount of organic polar solvent removed from the reaction system. It is acceptable to introduce the organic polar solvent into the system at any time, but if a dehydration operation is performed as described later, some of the organic polar solvent tends to evaporate from the system. Therefore, it is preferable to introduce the minimum amount necessary for dehydration before the dehydration operation, and then introduce additional amounts after the dehydration operation is completed to reach the above preferred amount.

[0029] (5)Water In this invention, water refers to water directly added during the preparation of raw materials, water introduced in conjunction with the added sulfidating agent, dihalogenated aromatic compound, organic polar solvent, and water generated during the reaction process. The amount of water present in the system at the start of the reaction is defined as the sum of the above minus the water removed from the system by dehydration. In this invention, the presence of water enhances the solubility of the sulfidating agent in the organic polar solvent, thereby promoting the reaction. However, excess water can reduce the nucleophilicity of the sulfidating agent, delaying the reaction and increasing the pressure within the system. Therefore, it is important to control the amount of water present in the system within a desirable range.

[0030] The preferred range for the amount of water present in the system at the start of the reaction is, as a lower limit, preferably as close to 0 moles per mole of sulfur in the sulfidating agent as possible, but as a practical lower limit for implementing the present invention, an example is 0.01 moles or more per mole of sulfur in the sulfidating agent. Furthermore, as an upper limit, 2.5 moles or less is preferred, and 2.0 moles or less is more preferred. When the amount of water at the start of the reaction is within the above preferred range, the reaction rate tends to be fast and by-products tend to be suppressed. In addition, the pressure rise in the system is suppressed, and the cost associated with introducing high-pressure equipment tends to be reduced.

[0031] In the present invention, if the amount of water at the start of the reaction exceeds the above-mentioned preferred amount of water, it is possible to adjust the amount of water by performing a dehydration operation to reduce the amount of water in the reaction system. There are no particular restrictions on the method of performing the dehydration operation. Any method can be employed, such as pre-dehydrating the raw materials to be charged, dehydrating a mixture in a state where one or more of the sulfidating agent, dihalogenated aromatic compound, or organic polar solvent are not added, or dehydrating a mixture containing the sulfidating agent, dihalogenated aromatic compound, and organic polar solvent after preparation. However, from the viewpoint of precisely controlling the amount of dihalogenated aromatic compound used, which is easily dispersed by heating, the method of performing the dehydration operation on a mixture in a state where the dihalogenated aromatic compound is not added is preferably employed. At this time, the temperature at which the mixture is heated varies depending on the combination of sulfidating agent and organic polar solvent used, as well as the ratio with water, and therefore cannot be clearly specified, but as a lower limit, 150°C or higher can be exemplified, preferably 160°C or higher, and more preferably 170°C or higher. Furthermore, an upper limit of 250°C or less can be exemplified, and preferably 230°C or less. When the heating temperature during dehydration is within the above preferred range, efficient dehydration can be performed while suppressing the scattering of the added sulfidating agent as hydrogen sulfide outside the system. There are also no particular restrictions on the pressure conditions during dehydration; atmospheric pressure, reduced pressure, or pressurized pressure can be used, but atmospheric pressure or reduced pressure is preferred for more efficient water removal. Here, atmospheric pressure refers to the pressure near the standard conditions of the atmosphere, which is a temperature of around 25°C and an absolute pressure of around 101 kPa. Furthermore, it is desirable that the atmosphere within the system be non-oxidizing, and an inert gas atmosphere such as nitrogen, helium, and argon is preferred, and in particular, a nitrogen atmosphere is more preferred from the viewpoint of economy and ease of handling.

[0032] (6) Method for producing polyarylene sulfide In the present invention, it is preferable to heat and react a mixture containing at least a sulfidating agent, a dihalogenated aromatic compound, and an organic polar solvent to produce PAS, and then perform the following steps 1, 2, 3, and 4 after the completion of the reaction that produces the PAS to obtain the PAS. Step 1: A step to obtain a solid component containing PAS by distilling off the organic polar solvent from the reaction mixture obtained at the end of the reaction. Step 2: Following Step 1, this step involves washing the solid components containing PAS with water. Step 3: Following Step 2, the PAS is washed with an organic solvent to reduce the amount of chloroform extract in the PAS to 1.7% by weight or less. Step 4: Following Step 3, this step involves heating while flowing an inert gas at a flow rate of 0.2 L / min or more per 1 kg of PAS to remove the organic solvent used in Step 3.

[0033] The following provides further details on these points.

[0034] (6-1) Chloroform extract In this invention, the chloroform extract component mainly refers to the oligomeric component contained in PAS, and is a component consisting of cyclic PAS and linear PAS oligomers. There are no particular restrictions on the ratio of these components.

[0035] Here, cyclic PAS refers to a cyclic compound whose main constituent unit is a repeating unit of formula -(Ar-S)-, and preferably a compound like the one shown in the general formula (Q) below, containing 80 mol% or more of the repeating unit.

[0036] [ka]

[0037] Here, as with the case of PAS described above, Ar can be exemplified by the units represented by formulas (A) to (L) above, but formula (A) is particularly preferred.

[0038] In cyclic PAS, repeating units such as those shown in formulas (A) to (L) above may be included randomly, in blocks, or as a mixture thereof. Representative examples of these include cyclic polyarylene sulfide, cyclic polyarylene sulfide sulfone, cyclic polyarylene sulfide ketone, cyclic random copolymers containing these, cyclic block copolymers, and mixtures thereof. Particularly preferred cyclic PAS are cyclic polyarylene sulfide (hereinafter sometimes abbreviated as cyclic PAS) containing 80 mol% or more, especially 90 mol% or more, of p-arylene sulfide units represented by the following formula as the main constituent unit.

[0039] [ka]

[0040] There are no particular restrictions on the number of repeats m in the above formula (Q) of the cyclic PAS, but 2 to 50 is preferred, 3 to 40 is more preferred, and 4 to 30 is even more preferred. Furthermore, the cyclic PAS may be a single compound having a single number of repeats, or a mixture of cyclic PAS having different numbers of repeats, but a mixture of cyclic PAS having different numbers of repeats is often obtained.

[0041] Furthermore, linear PAS oligomers are linear oligomers whose main constituent unit is a repeating unit of the formula -(Ar-S)-, and the structure of Ar is the same as that shown in the section on (A) polyarylene sulfide above. There is no limit to the number of repeats of the main constituent unit of the linear PAS oligomer, but for components extracted with chloroform, a repeating number of 2 to 20 is preferred, and a repeating number of 2 to 10 is a more preferred range. In addition, linear PAS oligomers may be single compounds having a single repeating number, or mixtures of linear PAS oligomers having different repeating numbers, but mixtures of linear PAS oligomers having different repeating numbers are often obtained.

[0042] In this invention, it is preferable to use PAS that reduces mold contamination by reducing oligomer components with relatively low volatility (high boiling point) that adhere to and accumulate on the mold during molding. However, it has been confirmed that such oligomer components are almost equal to chloroform extract components. Therefore, it is preferable to remove and reduce the chloroform extract components in the PAS. The less chloroform extract components there are in the PAS, the less mold contamination occurs during molding. It has been found that reducing the amount of chloroform extract components in the PAS to 1.7% by weight or less tends to improve mold contamination during molding. Therefore, in this invention, in step 3 described later, it is preferable to wash the PAS with an organic solvent to reduce the amount of chloroform extract components in the PAS to 1.7% by weight or less. As for the lower limit of the amount of chloroform extract components in the PAS, the less the better from the viewpoint of reducing mold contamination, so 0% by weight, where no chloroform extract components are contained in the PAS, is most preferable. On the other hand, as for the upper limit, 1.2% by weight or less is preferable, and 1.0% by weight or less is more preferable. When the amount of chloroform extract in PAS is within the above preferred range, mold contamination during the molding process of PAS tends to be more clearly improved.

[0043] In this invention, the amount of chloroform extractable component in PAS is calculated by weighing out 10 g of PAS, performing Soxhlet extraction with 100 g of chloroform for 3 hours, measuring the weight of the component obtained after distilling off the chloroform from the extract, and calculating the percentage relative to the weight of the charged polymer.

[0044] In this invention, it was stated that the amount of chloroform extract in PAS is preferable as it is from the viewpoint of reducing mold contamination during PAS molding. However, it is known that the chloroform extract in PAS exhibits a fluidizing effect that reduces the melt viscosity during melting when present in various resins. Therefore, if this effect is important, it may be acceptable for a certain amount of chloroform extract to be included in the PAS. Furthermore, cyclic PAS has potential applications in high-performance and functional materials based on its properties arising from its cyclic nature, such as its properties as a compound with inclusion ability, and its use as an effective monomer for the synthesis of high molecular weight linear polymers. Since the chloroform extract removed and recovered from PAS can be disposed of as waste, or the cyclic PAS can be separated and recovered as needed for use in other applications, this method is industrially preferable in that respect.

[0045] (6-2) Generation of PAS In this invention, a mixture containing at least a sulfidating agent, a dihalogenated aromatic compound, and an organic polar solvent is heated and reacted to produce PAS.

[0046] The temperature at which the mixture is heated and reacted in this invention cannot be specified in general terms, as it depends on the type and amount of raw materials used. However, a lower limit of 120°C or higher can be exemplified, preferably 180°C or higher, more preferably 220°C or higher, and even more preferably 240°C or higher. On the other hand, an upper limit of 350°C or lower can be exemplified, preferably 320°C or lower, more preferably 310°C or lower, and even more preferably 300°C or lower. When the temperature at which the mixture is heated and reacted is within the above preferred range, PAS exhibiting normal physical properties can be obtained more efficiently.

[0047] Here, if the temperature at which the mixture is heated and reacted exceeds the reflux temperature of the mixture under atmospheric pressure, examples of methods for heating at such a temperature include heating the mixture under a pressure exceeding atmospheric pressure, or heating the mixture in a pressure-resistant container, sealed in place. Atmospheric pressure refers to the pressure near the standard conditions of the atmosphere, which are atmospheric pressure conditions of approximately 25°C and an absolute pressure of approximately 101 kPa. The reflux temperature is the temperature at which the liquid components of the mixture repeatedly boil and condense. Furthermore, the reaction in this invention may be a reaction carried out at a constant temperature, a multi-step reaction in which the temperature is gradually increased, or a reaction in which the temperature is continuously changed.

[0048] Furthermore, the time for heating and reacting the mixture cannot be specified in general terms, as it depends on the type and amount of raw materials used and the reaction temperature. However, a lower limit of 0.5 hours or more is preferred, and 1 hour or more is more preferred. As an upper limit, 20 hours or less is preferred, and 10 hours or less is more preferred. When the time for heating and reacting the mixture is within the above preferred range, the raw materials can be sufficiently reacted and consumed, and PAS can be manufactured efficiently in a shorter time.

[0049] Furthermore, the pressure within the reaction system cannot be uniquely defined as it varies depending on the raw materials constituting the mixture, their composition, the reaction temperature, and the progress of the reaction. However, in a preferred embodiment of the present invention, the pressure at the reaction temperature of the present invention is preferably, as a lower limit, 0.25 MPa or higher in gauge pressure, more preferably 0.3 MPa or higher. As an upper limit, 5 MPa or lower is preferred, more preferably 3 MPa or lower, and even more preferably 2 MPa or lower. When the pressure within the reaction system is within the preferred range described above, the sulfidating agent and the dihalogenated aromatic compound, which are the raw materials, tend to react and consume rapidly, and the use of expensive pressure-resistant equipment tends to be avoided. Here, in order to set the pressure within the reaction system within the preferred range described above, the reaction system may be pressurized with an inert gas at any stage, such as before or during the reaction, preferably before the reaction starts. Here, gauge pressure refers to relative pressure with respect to atmospheric pressure, and is synonymous with the pressure difference obtained by subtracting atmospheric pressure from absolute pressure.

[0050] In the present invention, to produce PAS, it is preferable to heat and react a mixture containing at least a sulfidating agent, a dihalogenated aromatic compound, and an organic polar solvent, and then carry out step 1 described later after the completion of this reaction. In the present invention, "completion of reaction" refers to the state in which the reaction has continued until the conversion rate of the charged dihalogenated aromatic compound reaches 97% or more. After reacting the dihalogenated aromatic compound to such a conversion rate, the amount of chloroform extractant in the resulting PAS can be reduced by then carrying out step 1 described later. In the present invention, the reaction is considered to be complete when the conversion rate of the dihalogenated aromatic compound reaches 97% or more, but a method of further continuing the reaction to further increase the conversion rate of the dihalogenated aromatic compound is also preferably employed. In that case, a more preferable range for the conversion rate of the dihalogenated aromatic compound in the reaction is, as a lower limit, more preferably 98% or more, and even more preferably 98.5% or more. On the other hand, the upper limit may exceed 100% due to the calculation formula below, and cannot be defined definitively as it varies depending on the amount of dihalogenated aromatic compound used. However, the conversion rate when all of the used dihalogenated aromatic compound is converted can be considered a preferable upper limit. When the conversion rate of the dihalogenated aromatic compound is within the preferred range described above, the amount of chloroform extractant in the resulting PAS tends to decrease even further. In this invention, the amount of remaining dihalogenated aromatic compound in the reaction solution is estimated by gas chromatography, and the conversion rate of the dihalogenated aromatic compound is calculated from the ratio of the amount of sulfidating agent or dihalogenated aromatic compound used. The calculation formula is as follows. (a) When a dihalogenated aromatic compound is used in excess in molar ratio relative to the sulfidating agent Conversion rate of dihalogenated aromatic compounds (%) = [Amount of dihalogenated aromatic compound added (moles) - Amount of remaining dihalogenated aromatic compound (moles)] / Amount of sulfidizing agent added (moles) × 100 (b) In cases other than (a) above Conversion rate (%) of dihalogenated aromatic compounds = [Amount of dihalogenated aromatic compound added (moles) - Amount of remaining dihalogenated aromatic compound (moles)] / Amount of dihalogenated aromatic compound added (moles) × 100 Here, the amount of sulfidating agent added refers to the amount of sulfidating agent present in the system at the start of the reaction. If some of the sulfidating agent is removed from the system as hydrogen sulfide by a dehydration operation before the start of the reaction, the amount of sulfidating agent present in the system at the start of the reaction is estimated after considering the number of moles of hydrogen sulfide that was scattered.

[0051] Furthermore, the amount of dihalogenated aromatic compound added refers to the amount of dihalogenated aromatic compound present in the system at the start of the reaction. If some of the dihalogenated aromatic compound is removed from the system by dehydration before the start of the reaction, the amount of dihalogenated aromatic compound present in the system at the start of the reaction should be estimated after considering the number of moles that were scattered.

[0052] (6-3) Process 1 Step 1 in the present invention is a step of removing the organic polar solvent from the reaction mixture obtained in the reaction that produces PAS to obtain a solid containing PAS. The solid obtained in this operation contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidating agents. This operation allows for the easy recovery of the organic polar solvent and tends to reduce the cost of PAS production.

[0053] There are no particular limitations on the method for obtaining a solid containing PAS by distilling off the organic polar solvent from the reaction mixture. Examples include heating the resulting reaction mixture to a temperature above the boiling point of the organic polar solvent to distill it off, or using a pressure reactor equipped with a discharge port at the bottom of the container to heat the reaction mixture in a sealed state. Once the reaction mixture is heated to a temperature above the boiling point at atmospheric pressure, the discharge port at the bottom of the container is opened, and the reaction mixture is released into an atmospheric or reduced-pressure atmosphere to instantly vaporize and distill off the organic polar solvent (flash method).

[0054] The temperature at which the organic polar solvent is removed in step 1 is not particularly limited as long as it is above the boiling point of the organic polar solvent used. However, a lower limit of 200°C or higher is preferred, 220°C or higher is more preferred, and temperatures exceeding 220°C are even more preferred. On the other hand, an upper limit of 250°C or lower is preferred, and 240°C or lower is even more preferred. When the temperature at which the organic polar solvent is removed in step 1 is within the above preferred range, the removal of the organic polar solvent is completed in a relatively short time, and the resulting PAS particles do not fuse together. As a result, the solid obtained after flashing does not form large clumps and tends to become an easy-to-handle powder. Furthermore, the specific surface area of ​​the obtained PAS particles tends to increase, and this effect makes it easier to reduce the amount of chloroform extractable components in the PAS when the PAS is washed with an organic solvent in step 3, which will be described later. Here, the temperature at which the organic polar solvent is removed in step 1 refers to the internal temperature, not the temperature of the container.

[0055] When the reaction mixture described above is heated above the boiling point of the organic polar solvent to remove the organic polar solvent by distillation, the pressure conditions can be atmospheric pressure, reduced pressure, or pressurized pressure, but reduced pressure is preferable. Under such preferred pressure conditions, the rate of distillation of the organic polar solvent can be increased, and additional effects such as the removal of oligomer components and other volatile impurities along with the organic polar solvent tend to be obtained.

[0056] Furthermore, when employing the flash method described above, there are no particular restrictions on the conditions, but preferred conditions include a reaction mixture that is typically subjected to high temperature and high pressure conditions of 250°C or higher and 0.8 MPa or higher, followed by a reaction mixture of approximately 290°C and 5 kg / cm³. 2 More than 20kg / cm 2An example of a method is to release the adjusted high-temperature, high-pressure steam into an airflow at a flow rate of 50 kg / hr to 5,000 kg / hr. The supply rate of the reaction mixture in this case is preferably in the range of 0.5 kg / hr to 5,000 kg / hr. Such a preferred method tends to efficiently remove oligomeric components and other volatile impurities by entraining them with the steam, and the solid obtained after flashing tends to be in the form of an easily handleable powder rather than large lumps.

[0057] Furthermore, in the flash method, the temperature of the container from which the reaction mixture is extracted is not particularly limited as long as it is above the boiling point of the organic polar solvent used at atmospheric pressure, but a lower limit of 200°C or higher is preferred, and 220°C or higher is more preferred. On the other hand, an upper limit of 250°C or lower is preferred, and 240°C or lower is more preferred. When the temperature of the container from which the reaction mixture is extracted in the flash method is within the above preferred range, the removal of the organic polar solvent can be completed in a relatively short time, and the resulting PAS particles can be prevented from fusing together, so that the solid obtained after flashing does not form large clumps and tends to be in the form of an easy-to-handle powder. In addition, the specific surface area of ​​the obtained PAS particles tends to increase, and this effect makes it easier to reduce the amount of chloroform extractable components in the PAS when the PAS is washed with an organic solvent in step 3 described later.

[0058] As described above, in step 1, the organic polar solvent is removed from the reaction mixture obtained from the reaction to obtain a solid containing PAS. An advantage of this operation is that the organic polar solvent can be recovered at low cost. The obtained reaction mixture contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidating agents, so it is necessary to wash with water to some extent during the PAS recovery process. However, the filtrate produced in this process often contains water, water-soluble substances, and the organic polar solvent. When the organic polar solvent is recovered from such a filtrate by distillation or other means, water is a substance with a large latent heat of vaporization, so it is very costly, and as a result the cost of PAS production tends to increase significantly. In the present invention, the above situation can be avoided by recovering the organic polar solvent first, so it is possible to produce PAS at low cost.

[0059] (6-4) Process 2 Step 2 in the present invention is a step that follows Step 1, in which the solid containing PAS is washed with water to remove water-soluble substances. The solid obtained after the organic polar solvent is removed by distillation in Step 1 contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidating agents, so these water-soluble substances are removed by washing with water in the subsequent Step 2.

[0060] There are no particular restrictions on the method of washing the solid containing PAS with water to remove water-soluble substances. For example, one method involves adding water to the solid containing PAS to form a slurry, then separating the solid and liquid by operations such as filtration or centrifugation, and recovering the PAS as a solid to remove water-soluble substances into the filtrate. Another method involves spreading the PAS on a filter medium and washing it with water. In the slurrying operation described above, stirring is preferable from the viewpoint of efficiently removing water-soluble substances.

[0061] When washing a solid containing PAS with water to remove water-soluble substances, there are no particular restrictions on the bath ratio (gravimetric bath ratio) of water to PAS. However, a lower limit can be exemplified by a bath ratio of 1 or more relative to the weight of PAS, preferably 2 or more, and more preferably 3 or more. On the other hand, an upper limit can be exemplified by a bath ratio of 100 or less relative to the weight of PAS, preferably 50 or less, and more preferably 20 or less. When the bath ratio when washing a solid containing PAS with water to remove water-soluble substances is within the above preferred range, water-soluble substances tend to be removed efficiently. Furthermore, when solid-liquid separation is performed after slurrying by operations such as filtration or centrifugation, the process tends to be completed in a short time.

[0062] There are no particular restrictions on the temperature (slurry temperature) when washing the solid components containing PAS with water to remove water-soluble substances. However, a lower limit can be 0°C or higher, preferably 100°C or higher, more preferably 150°C or higher, even more preferably 170°C or higher, and even more preferably 180°C or higher. On the other hand, an upper limit can be 250°C or lower, preferably 220°C or lower, and more preferably 200°C or lower. When the temperature when washing PAS with water to remove water-soluble substances is within the above preferred range, the internal pressure of the apparatus does not rise excessively, and water-soluble substances embedded inside the PAS particles tend to be efficiently extracted. There are no particular restrictions on the method of raising the temperature above the boiling point of water. For example, one method is to put PAS and water in a pressure-resistant container, form a slurry, seal it, and heat it.

[0063] Furthermore, there are no particular restrictions on the stirring time when washing the solid components containing PAS with water to remove water-soluble substances, but a minimum of 0.1 minutes is exemplified as a lower limit, and 1 minute or more is preferred. A maximum of 3 hours or less is exemplified as an upper limit, and 1 hour or less is preferred. When the stirring time when washing PAS with water to remove water-soluble substances is within the above preferred range, there is a tendency for water-soluble substances contained in PAS to be extracted efficiently.

[0064] Furthermore, there are no particular restrictions on the temperature inside the solid-liquid separation apparatus when separating the solid-liquid mixture from the solid containing PAS by slurring with water and then performing operations such as filtration or centrifugation. However, a lower limit can be 0°C or higher, preferably 20°C or higher, and more preferably 50°C or higher. On the other hand, an upper limit can be 100°C or lower. When the temperature inside the solid-liquid separation apparatus is within the above preferred range, the solid-liquid separation operation can be performed using a simple apparatus without being affected by the boiling or melting point of water at atmospheric pressure.

[0065] Furthermore, there are no particular restrictions on the number of times the solid containing PAS is washed with water to remove water-soluble substances. However, if the operation is performed only once, water-soluble substances tend to remain due to the mother liquor in the solid obtained after separation. Therefore, it is preferable to perform the washing operation two or more times. By performing the washing operation multiple times in this way, it is possible to remove even more water-soluble substances.

[0066] Furthermore, while there is no problem in washing the solid components containing PAS with water to remove water-soluble substances under atmospheric conditions, it is preferable to do so under non-oxidizing conditions from the viewpoint of preventing decomposition and oxidation of end groups. In this case, an inert gas atmosphere such as nitrogen, helium, and argon is preferred, and a nitrogen atmosphere is particularly preferred from the viewpoint of economy and ease of handling.

[0067] Furthermore, when washing solid components containing PAS with water, a method of adding acid to the water used for washing tends to reduce the metal content in PAS and is therefore preferred. There are no particular restrictions on the acid added, as long as it does not exhibit an oxidative, decomposing, or degrading effect on PAS; both inorganic and organic acids can be used. At this time, it is preferable to perform the acid washing under conditions such that the slurry pH during acid washing is less than 7, and this is controlled by adjusting the type of acid selected from inorganic and organic acids and the amount added. Examples of acids that can be added include acetic acid, hydrochloric acid, dilute sulfuric acid, phosphoric acid, silicic acid, carbonate, and propyl acid, and these acids may be used individually or in mixtures. Among these, acetic acid and hydrochloric acid are preferred from a cost perspective. After washing with water with added acid, it is preferable to perform at least one additional wash with normal water to ensure that the added acid does not remain in the PAS.

[0068] Furthermore, when washing PAS with water using added acid, it is desirable to use an inert atmosphere to suppress the decomposition and oxidation of the terminal groups of PAS.

[0069] Furthermore, in step 2, the PAS becomes wet after washing with water, but it is also possible to dry the PAS afterward. Since water is a poor solvent for the chloroform extract components in the PAS, drying the PAS in step 2 tends to increase the cleaning effect when washing the PAS with an organic solvent in the subsequent step 3. However, if the organic solvent used in step 3 is not water-soluble, the cleaning effect tends to be the same whether the PAS is dry or wet, so it is not always necessary to dry the PAS in step 2.

[0070] When drying PAS after washing it with water in step 2, if the drying temperature is too high, the PAS particles tend to fuse together, reducing the specific surface area, and thus failing to achieve a sufficient cleaning effect in step 3 described later. Therefore, a lower limit of 70°C or higher is preferable, 100°C or higher is more preferable, and 120°C or higher is even preferable. A higher limit of 170°C or lower is preferable, and 150°C or lower is even preferable. When the drying temperature of PAS is within the above preferred range, the specific surface area of ​​the PAS after drying increases, making it easier to thoroughly wash and remove the extracted components from chloroform in the PAS in step 3 described later. Furthermore, drying tends to be efficient and quick. The drying atmosphere is preferably non-oxidizing, preferably an inert gas atmosphere such as nitrogen, helium, or argon, and is particularly preferable under a nitrogen atmosphere from the viewpoint of economy and ease of handling. Drying PAS under such an atmosphere tends to prevent deterioration of PAS due to oxidation.

[0071] Furthermore, when drying the PAS after washing it with water in step 2, there are no particular restrictions on the drying time, but a minimum of 0.5 hours is a good example, and a minimum of 1 hour is preferable. A maximum of 50 hours is a good example, a minimum of 20 hours is preferable, and a minimum of 10 hours is more preferable. When the drying time of the PAS is within the above preferred range, the PAS can be manufactured industrially efficiently.

[0072] In step 2, when the PAS is washed with water and then dried, there are no particular restrictions on the type of dryer used. A general vacuum dryer or hot air dryer can be used, and it is also possible to use a rotary or agitator-equipped heating device or a fluidized bed dryer. However, from the viewpoint of efficiently and uniformly drying the PAS, it is preferable to use a rotary or agitator-equipped heating device for drying.

[0073] (6-5) Process 3 Step 3 in the present invention is a step following Step 2 in which the PAS is washed with an organic solvent to reduce the amount of chloroform extract in the PAS to 1.7% by weight or less. When PAS is manufactured by a preferred method, (particularly influenced by the amount of organic polar solvent used during the reaction), the amount of chloroform extract in the PAS is often between 2.0% by weight and 5.0% by weight at the end of Step 2. As described above, this chloroform extract in the PAS has been confirmed to be the main cause of mold contamination when the PAS is molded. Therefore, by performing Step 3 and reducing the content of chloroform extract in the PAS, it is possible to reduce mold contamination during molding.

[0074] In step 3, it is preferable to wash the PAS with an organic solvent to reduce the amount of chloroform extract in the PAS to 1.7% by weight or less. If the amount of chloroform extract in the PAS exceeds 1.7% by weight, mold contamination during the molding process of the PAS will not be significantly improved, and the effects of the present invention will not be obtained. As for the lower limit of the amount of chloroform extract in the PAS, the lower the amount, the better from the viewpoint of reducing mold contamination, so 0% by weight, where no chloroform extract is contained in the PAS, is most preferable. On the other hand, as for the upper limit, 1.2% by weight or less is more preferable, and 0.9% by weight or less is even more preferable. When the amount of chloroform extract in the PAS is within the above preferred range, mold contamination during the molding process of the PAS tends to be more significantly improved.

[0075] In step 3, the organic solvent used for washing PAS is not particularly limited as long as it has high solubility for the chloroform extract components in PAS, low solubility for PAS, and does not exhibit an oxidative, decomposing, or degrading effect on PAS. Examples include amide-based polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, and dimethylimidazolidinone; sulfoxide-sulfone solvents such as dimethyl sulfoxide and dimethyl sulfone; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; ether solvents such as dimethyl ether, diethyl ether, dipropyl ether, tetrahydrofuran, and diphenyl ether; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; nitrile solvents such as acetonitrile; chloroform, methylene chloride, trichloroethylene, dichloroethylene, and 1,2 Examples of suitable solvents include halogenated solvents such as -dichloroethane, tetrachloroethane, chlorobenzene, and 1-chloronaphthalene; alcohol-phenolic solvents such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, and polyethylene glycol; and aliphatic-aromatic hydrocarbon solvents such as n-hexane, cyclohexane, benzene, toluene, and p-xylene. Among these, N-methyl-2-pyrrolidone, dimethylformamide, tetrahydrofuran, chloroform, 1-chloronaphthalene, toluene, and p-xylene are preferred because they tend to have high solubility for chloroform extracts in PAS. Furthermore, N-methyl-2-pyrrolidone, which is often used as a polymerization solvent for PAS, is particularly preferred from the viewpoint of availability. These organic solvents may be used individually or as a mixture of two or more solvents.

[0076] In this invention, the amount of chloroform extractant in PAS is measured by the following method. First, 10 g of PAS is weighed out and Soxhlet extraction is performed with 100 g of chloroform for 3 hours. The weight of the extract after removing the chloroform by distillation is measured, and the ratio to the weight of the polymer is determined to be the amount of chloroform extractant.

[0077] Step 4, described later, is a process in which the organic solvent used in Step 3 is removed by heating while flowing an inert gas. However, when Step 4 is carried out under favorable conditions, the amount of chloroform extractant in the PAS hardly changes before and after the execution of Step 4. Therefore, the amount of chloroform extractant in the PAS after Step 3 shall be evaluated by the amount of chloroform extractant in the PAS after Step 4.

[0078] Furthermore, in step 3, it is preferable that the water content of the PAS before washing with the organic solvent be 30% by weight or less. Since water is a poor solvent for the chloroform extract components in the PAS, reducing the water content of the PAS tends to make it easier to further reduce the chloroform extract components when the PAS is washed with the organic solvent. Note that if the organic solvent used to wash the PAS in step 3 is a water-insoluble organic solvent such as chloroform or toluene, a stable cleaning effect tends to be obtained regardless of the water content of the PAS, so it is not necessarily required to reduce the water content of the PAS to 30% by weight or less. However, considering that N-methyl-2-pyrrolidone, which is a particularly preferred cleaning solvent from the viewpoint of availability, is a water-soluble organic solvent, it is preferable to reduce the amount of water in the PAS. Here, as the lower limit of the water content of the PAS before washing with the organic solvent, the lower the better in order to enhance the cleaning effect, and 0% by weight, where no water is contained in the PAS, is the most preferable. On the other hand, as the upper limit, 10% by weight or less is more preferable, 5% by weight or less is even more preferable, and 1% by weight or less is even more preferable, as exemplified by this. In step 3, when the moisture content of the PAS before washing with an organic solvent is within the preferred range described above, using a water-soluble organic solvent for washing the PAS tends to further reduce the amount of chloroform extractant in the PAS. As mentioned earlier, one method for reducing the moisture content to 30% by weight or less is to dry the PAS after washing with water in step 2.

[0079] In this invention, the moisture content of PAS is measured in accordance with the Japanese Industrial Standard JIS K 7251, using the Karl Fischer method.

[0080] Generally, it is known that in operations where particles are washed with a solvent, the washing efficiency tends to increase as the specific surface area of ​​the particles increases, and this trend is also observed in the washing process in step 3. Specifically, in step 3, the specific surface area of ​​PAS before washing with the organic solvent is set to a minimum of 5 m². 2 Preferably, a value of 8m or more can be exemplified. 2 More preferably 10m / g or more, 2 A value of 50 / g or more is even more preferable. On the other hand, an upper limit of 50m 2 A value of less than or equal to / g is preferred as an example. In step 3, when the specific surface area of ​​the PAS before washing with the organic solvent is within the above preferred range, washing the PAS with the organic solvent tends to further reduce the amount of chloroform extractant in the PAS.

[0081] Furthermore, the specific surface area of ​​the PAS before washing with the organic solvent in step 3 can be adjusted, as described above, by the temperature at which the organic polar solvent is distilled off the reaction mixture in step 1, and the drying temperature when the PAS is dried after washing with water in step 2. The lower limit of the temperature at which the organic polar solvent is distilled off the reaction mixture in step 1 is preferably 200°C or higher, and more preferably 220°C or higher. On the other hand, the upper limit is preferably 250°C or lower, and more preferably 240°C or lower. When the temperature at which the organic polar solvent is distilled off the reaction mixture in step 1 is within the above preferred range, it is possible to prevent the PAS particles from fusing together, and the specific surface area of ​​the PAS before washing with the organic solvent in step 3 tends to be adjusted to the above preferred range. Also, as described in step 2, the drying temperature when the PAS is dried after washing with water is preferably 70°C or higher and 170°C or lower. When drying PAS after washing it with water in step 2, if the drying temperature is within the above preferred range, it is possible to prevent the PAS particles from fusing together, and it tends to be easier to adjust the specific surface area of ​​PAS before washing with an organic solvent in step 3 to the above preferred range.

[0082] Here, the specific surface area of ​​PAS is measured by weighing 0.2 g of PAS into a glass cell, degassing under reduced pressure at room temperature for 5 hours, measuring by krypton gas adsorption, and then determining the specific surface area by BET multipoint analysis.

[0083] There are no particular restrictions on the method of washing PAS with an organic solvent to remove chloroform extract components from PAS. For example, one method involves adding an organic solvent to PAS to form a slurry, then separating the solid and liquid components by operations such as filtration or centrifugation, and recovering the PAS as solids to remove the chloroform extract components from the PAS into the filtrate. Another method involves spreading PAS on a filter medium and washing it with an organic solvent. In the slurrying operation described above, stirring is preferable from the viewpoint of efficiently removing chloroform extract components from PAS.

[0084] When washing PAS with an organic solvent to remove chloroform extract components from PAS, there are no particular restrictions on the bath ratio (weight bath ratio) of the amount of organic solvent to the amount of PAS. However, as a lower limit, an example is a bath ratio of 1 or more relative to the weight of PAS, preferably 2 or more, and more preferably 3 or more. On the other hand, as an upper limit, an example is a bath ratio of 100 or less relative to the weight of PAS, preferably 50 or less, and more preferably 20 or less. When the bath ratio when washing PAS with an organic solvent to remove chloroform extract components from PAS is within the above preferred range, there is a tendency to be able to efficiently remove the chloroform extract components from PAS. Furthermore, when solid-liquid separation is performed after slurrying by operations such as filtration or centrifugation, there is a tendency for the process to be completed in a short time.

[0085] There are no particular restrictions on the temperature (slurry temperature) when washing PAS with an organic solvent to remove chloroform extract components from PAS, but a lower limit can be 0°C or higher, preferably 20°C or higher, and more preferably 60°C or higher. On the other hand, an upper limit can be 300°C or lower, preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 150°C or lower. When the temperature when washing PAS with an organic solvent to remove chloroform extract components from PAS is within the above preferred range, the pressure tends to not rise excessively, and the chloroform extract components from PAS tend to be extracted efficiently. In addition, when solid-liquid separation is performed by filtration or centrifugation after slurring PAS with an organic solvent, the solid-liquid separation rate tends to increase, and processing tends to be more efficient. There are no particular restrictions on the method of raising the temperature above the boiling point of the organic solvent, but for example, a method of slurring PAS and an organic solvent in a pressure-resistant container, sealing it, and heating it can be exemplified.

[0086] Furthermore, there are no particular restrictions on the stirring time when washing the PAS with an organic solvent to remove the chloroform extract from the PAS, but a lower limit of 0.1 minutes or more is exemplified, 1 minute or more is preferred, and 5 minutes or more is more preferred. A higher limit of 3 hours or less is exemplified, 1 hour or less is preferred, and 30 minutes or less is more preferred. When the stirring time when washing the PAS with an organic solvent to remove the chloroform extract from the PAS is within the above preferred range, the chloroform extract tends to be extracted efficiently.

[0087] Furthermore, there are no particular restrictions on the temperature inside the solid-liquid separation apparatus when PAS is slurryed with an organic solvent and then separated into solid and liquid components by operations such as filtration or centrifugation. However, a lower limit can be 0°C or higher, preferably 20°C or higher, and more preferably 60°C or higher. On the other hand, an upper limit can be 300°C or lower, preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 150°C or lower. When the temperature inside the solid-liquid separation apparatus is within the above preferred range, the solid-liquid separation operation can be performed using simple equipment without the need for expensive pressure-resistant equipment. In addition, the solid-liquid separation rate tends to increase, and processing can be performed more efficiently.

[0088] Here, specific operations for solid-liquid separation include filtration and centrifugation, but in order to reduce the amount of mother liquor contained in the solid obtained after solid-liquid separation, a method of pressurizing the solid after solid-liquid separation is also preferably employed. By performing such an additional operation, the amount of mother liquor contained in the solid is reduced, and there is a tendency for the chloroform extract component in the PAS contained in the PAS to be further reduced.

[0089] Furthermore, there are no particular restrictions on the number of times the PAS is washed with an organic solvent to remove the chloroform extract components from the PAS. However, if the operation is performed only once, the chloroform extract components in the PAS tend to remain due to the mother liquor in the solid obtained after separation. Therefore, it is preferable to perform the washing operation two or more times. By performing the washing operation multiple times in this way, it is possible to remove the chloroform extract components even more effectively.

[0090] Furthermore, while washing PAS with an organic solvent to remove chloroform extract components from PAS can be done under atmospheric conditions without any problems, it is preferable to do so under non-oxidizing conditions from the viewpoint of preventing decomposition and oxidation of end groups. In this case, an inert gas atmosphere such as nitrogen, helium, and argon is preferred, and a nitrogen atmosphere is particularly preferred from the viewpoint of economy and ease of handling.

[0091] (6-6) Process 4 Step 4 in the present invention is a step that follows Step 3, in which the organic solvent used in Step 3 is removed by distillation while heating with an inert gas flow rate of 0.2 L / min or more per kg of PAS. By performing Step 4, it is possible to obtain a PAS that has less mold contamination during molding, excellent melting and flowability, and high reactivity with coupling agents.

[0092] In step 4, if the organic solvent used in step 3 is removed by heating under conditions where the flow rate of the inert gas is less than 0.2 L / min per kg of PAS, the PAS tends to undergo thermal denaturation, reducing the reactivity between PAS and the coupling agent, and making it difficult to improve the heat and humidity resistance of the compound obtained by melt-kneading with other resins or inorganic fillers. Here, the lower limit of the flow rate of the inert gas when removing the organic solvent in step 4 is preferably 0.4 L / min or more, and more preferably 0.8 L / min or more. The upper limit is preferably 50 L / min or less, and more preferably 25 L / min or less. When the flow rate of the inert gas when removing the organic solvent in step 4 is within the above preferred range, the thermal denaturation of PAS can be suppressed more effectively, and the heat and humidity resistance of the compound obtained by melt-kneading with other resins or inorganic fillers tends to improve.

[0093] Here, an inert gas is a stable gas that does not undergo chemical reactions. Nitrogen, helium, and argon can be preferably used, but nitrogen is more preferable from the viewpoint of economy and ease of handling. In step 4, the oxygen concentration in the apparatus used to distill off the organic solvent tends to be low because an inert gas is flowing through it. However, the lower limit of the oxygen concentration in the apparatus should be as low as possible to prevent oxidation of PAS, with 0% by volume being the most preferable, meaning no oxygen is present in the apparatus at all. On the other hand, the upper limit should be 1% by volume or less, more preferably 0.1% by volume or less, and even more preferably 0.01% by volume or less. When the oxygen concentration in the apparatus used to distill off the organic solvent in step 4 is within the above preferred range, the degradation of PAS due to oxidation tends to be more effectively prevented.

[0094] In step 4, there are no particular restrictions on the pressure inside the apparatus used to distill off the organic solvent. Any of atmospheric pressure, reduced pressure, or increased pressure conditions can be used. However, adopting reduced pressure or increased pressure conditions requires the introduction of expensive equipment capable of withstanding those pressure environments. Therefore, from the viewpoint of manufacturing PAS more economically, atmospheric pressure is preferred. Here, atmospheric pressure refers to the pressure near the standard conditions of the atmosphere, which is a temperature of around 25°C and an absolute pressure of around 101 kPa.

[0095] Furthermore, in step 4, there are no particular restrictions on the temperature at which the organic solvent is removed by distillation, but a lower limit of 70°C or higher is exemplified, 100°C or higher is preferred, and 120°C or higher is more preferred. A higher upper limit of 250°C or lower is exemplified, and 230°C or lower is more preferred. When the drying temperature of the PAS is within the above preferred range, the PAS tends to dry efficiently in a short time without fusing.

[0096] Furthermore, there are no particular restrictions on the time for removing the organic solvent in step 4, but a minimum of 0.1 hours is a good example of a lower limit, and a minimum of 1 hour is preferred. A maximum of 50 hours or less is a good example, a minimum of 20 hours is preferred, and a minimum of 10 hours is more preferred. When the drying time of PAS is within the above preferred range, PAS can be manufactured industrially efficiently while suppressing thermal denaturation.

[0097] In step 4, there are no particular restrictions on the dryer used to remove the organic solvent; a general vacuum dryer or hot air dryer can be used, and a rotary or agitator-equipped heating device or a fluidized bed dryer can also be used. However, from the viewpoint of efficiently and uniformly drying the PAS, it is preferable to dry it using a rotary or agitator-equipped heating device.

[0098] Furthermore, if the organic solvent used for washing in step 3 has a high boiling point, the process of removing the organic solvent in step 4 tends to be performed at a high temperature and for a long time. To mitigate this, it is preferable to replace the organic solvent contained in the PAS with another solvent with a lower boiling point before performing step 4 and then drying it. Here, there are no particular restrictions on the solvent to be replaced, as long as it is miscible with the solvent used for washing, but water or acetone are often preferred from the viewpoint of being inexpensive, readily available, and having a relatively low boiling point. Examples of methods for replacing the organic solvent contained in the PAS with another solvent with a lower boiling point include adding the replacement solvent to the PAS to form a slurry and then separating the solid and liquid by operations such as filtration or centrifugation, or spreading the PAS on a filter medium and washing it by pouring the replacement solvent over it. This operation is effective even if performed only once, but performing it two or more times to further advance the solvent replacement tends to make it easier to perform the drying process at a lower temperature and for a shorter time.

[0099] In this invention, step 4 is a step in which the organic solvent used in step 3 is removed by distillation while heating with an inert gas flow. However, when step 4 is carried out under favorable conditions, the amount of chloroform extractant in the PAS hardly changes before and after step 4. Therefore, the amount of chloroform extractant in the PAS after step 3 can be evaluated by the amount of chloroform extractant in the PAS after step 4.

[0100] (7) Other post-processing The PAS thus obtained has sufficiently little mold contamination during molding. However, in order to further reduce mold contamination, it is also preferable to perform additional heat treatment (curing) on ​​the PAS obtained after step 4 to obtain (A) polyarylene sulfide having a crosslinked structure.

[0101] While there are no particular restrictions on the temperature at which the PAS obtained after step 4 is subjected to additional heat treatment, a lower limit of 150°C or higher is exemplified, and 160°C or higher is preferred. Furthermore, an upper limit of 270°C or lower is exemplified, and 260°C or lower is preferred. When the heat treatment temperature of the PAS is within the above preferred range, excessive thermal deformation of the PAS is avoided, mold contamination generated during the molding process of the PAS can be further reduced, and mechanical strength can be easily improved. Additionally, the PAS tends to be heat-treated more uniformly without fusing.

[0102] Furthermore, there are no particular restrictions on the time for additional heat treatment of the PAS obtained after the execution of step 4, but a minimum of 0.2 hours is a good example of a lower limit, and 0.3 hours or more is preferred. A maximum of 50 hours or less is a good example of an upper limit, 20 hours or less is preferred, 10 hours or less is more preferred, and 6 hours or less is even more preferred. When the heat treatment time for the PAS is within the above preferred range, the mold contamination that occurs during the molding process of the PAS can be further reduced without excessive thermal deformation of the PAS, and the mechanical strength can also be easily improved.

[0103] Here, when additional heat treatment is performed on the PAS obtained after step 4, there are no particular restrictions on the equipment used, and a general vacuum dryer or hot air dryer can be used, and it is also possible to use a rotary or impeller-equipped heating device, a fluidized bed dryer, etc. However, from the viewpoint of efficiently and uniformly heat-treating the PAS, it is preferable to use a rotary or impeller-equipped heating device for heat treatment. Furthermore, when additional heat treatment is performed on the PAS obtained after step 4, it is preferable to perform the heat treatment under non-oxidizing conditions from the viewpoint of preventing decomposition and oxidation of end groups, however, this heat treatment may also be performed for the purpose of increasing the melt viscosity of the PAS, in which case the heat treatment may be performed under an atmosphere containing a certain amount of oxygen. In this case, the oxygen concentration can be exemplified as a lower limit of 0.5 volume% or more, and preferably exemplified as 1 volume% or more. On the other hand, the upper limit can be exemplified as 50 volume% or less, preferably 25 volume% or less, and more preferably 15 volume% or less. When the oxygen concentration in the atmosphere during the heat treatment of PAS is within the above preferred range, it tends to be easier to control the melt viscosity of PAS to the desired viscosity without excessive thermal deformation of the PAS. Furthermore, when additionally heat-treating the PAS obtained after step 4, it is preferable to flow the airflow at a certain velocity from the viewpoint of efficiently advancing the heat treatment. As an example of this velocity, a lower limit of 0.1 L / min or more per 1 kg of resin can be exemplified. On the other hand, as an upper limit, a 50 L / min or less per 1 kg of resin can be exemplified, 30 L / min or less is preferred, and 15 L / min or less is more preferred. When the airflow velocity during the heat treatment of PAS is within the above preferred range, it tends to be possible to heat-treat the PAS efficiently.

[0104] An example of a PAS having a desirable crosslinking structure is when the PAS is dissolved in 20 times its weight of 1-chloronaphthalene at 250°C for 5 minutes, and the amount of residue after hot pressure filtration through a PTFE membrane filter with a pore size of 1 μm is 4.0% by weight or less. In the present invention, it is preferable that the (A) PAS used has a residue amount of 4.0% by weight or less. When the residue amount is 4.0% by weight or less, the thermal oxidation crosslinking of the PAS proceeds appropriately, preventing an increase in gelled material in the resin. By allowing the thermal oxidation crosslinking of the PAS to proceed appropriately, it is possible to prevent a decrease in the tensile elongation and impact strength of the PAS, as well as suppress the increase in melt viscosity and maintain excellent melt moldability. A more preferable upper limit for the residue amount is 3.0% by weight or less, and even more preferable is 2.0% by weight or less. There is no particular lower limit for the residue amount, but a preferably 0.5% by weight or more is a good example.

[0105] The above-mentioned residue amount is measured using a SUS test tube equipped with a high-temperature filtration device, a pneumatic cap, and a collection funnel, with the sample being a pressed film of PAS approximately 80 μm thick. Specifically, a membrane filter with a pore size of 1 μm is first set in the SUS test tube, and then the pressed film of PAS approximately 80 μm thick and 1-chloronaphthalene 20 times its weight are weighed and sealed. This is then placed in a high-temperature filtration device at 250°C and heated and shaken for 5 minutes. Next, a syringe containing air is connected to the pneumatic cap, and the syringe piston is pushed out to perform thermal filtration by pneumatic pressure. The specific quantitative method for the residue amount is to determine it from the weight difference between the membrane filter before filtration and the membrane filter after filtration and vacuum drying at 150°C for 1 hour. A preferred method for controlling the amount of PAS residue used in the present invention to 4.0% by weight or less is to moderately thermally oxidize the PAS by setting the processing temperature to 160-220°C, the oxygen volume concentration to 2% to 25% by volume, and the processing time to 0.2-20 hours. Under these oxidation conditions, moderate oxidative crosslinking is promoted, and the amount of PAS residue can be reduced to 4.0% by weight or less.

[0106] (8) Characteristics of the PAS used in the present invention The PAS used in this invention has been found to exhibit a characteristic molecular weight distribution not seen in conventional PAS when its molecular weight is measured by gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). Specifically, it exhibits a molecular weight distribution shape such that, when the cumulative integral value from molecular weight 100 to 10,000 is set to 100, the cumulative integral value at molecular weight 4,000 is between 48 and 53. For example, in the so-called quench method for producing PAS, after polymerization of PAS, water is added to the system before the deposition of PAS particles and then slowly cooled to increase the PAS particle size. However, such processing tends to make the PAS particles porous, and washing with organic solvents tends to remove oligomer components that are not the cause of mold contamination more than necessary. PAS obtained by this quenching method exhibits a molecular weight distribution shape such that the cumulative integral value at a molecular weight of 4,000 is less than 48 when the cumulative integral value from molecular weight 100 to 10,000 is set to 100 in the molecular weight distribution curve. This tends to result in a material with less mold contamination during molding but low melt fluidity and poor moldability. On the other hand, in the so-called flash method for producing PAS, the high-temperature reaction system is flashed into a container under atmospheric or reduced pressure after polymerization of PAS to remove the polymerization solvent. The greatest advantage of this method is widely recognized as being the low cost of producing PAS, and there is no idea to perform a cleaning operation with organic solvents at an additional cost. PAS obtained by this flash method exhibits a molecular weight distribution shape such that the cumulative integral value at a molecular weight of 4,000 is greater than 53 when the cumulative integral value from molecular weight 100 to 10,000 is set to 100 in the molecular weight distribution curve. This tends to result in a material with high melt fluidity but significant mold contamination during molding. Compared to the conventional PAS described above, the PAS used in the present invention is a material that achieves both low mold contamination during molding and high melt flowability, and can be said to be a material with superior moldability. Here, the melt flowability of the PAS in the present invention is evaluated by measuring the melt flow rate (resin discharge amount per 10 minutes) in accordance with ASTM-D1238-70 and comparing the values.

[0107] Furthermore, the PAS used in this invention must have a change rate expressed as MFR2 / MFR1 of 0.085 or less, where MFR1 is the melt flow rate of the PAS, and MFR2 is the melt flow rate obtained after mixing the PAS and the epoxysilane coupling agent in a weight ratio of 100:1 and heating at 315.5°C for 5 minutes. This means that the melt viscosity increases as the PAS and the epoxysilane coupling agent react, and the smaller this change rate, the greater the increase in melt viscosity. If the change rate expressed as MFR2 / MFR1 exceeds 0.085, there will be problems with inferior mechanical strength and hydrolysis resistance when compounded by melt-kneading with other resins or inorganic fillers. To obtain such a PAS, in step 4 of this invention, the organic solvent used in step 3 should be removed by distillation while heating with an inert gas flow rate of 0.2 L / min or more per kg of PAS. PAS, which reacts with epoxysilane coupling agents to significantly increase its melt viscosity, tends to exhibit improved mechanical strength and heat and humidity resistance when melt-kneaded with other resins or inorganic fillers to form a compound, making it suitable for applications requiring heat and humidity resistance. There is no particular limit to the lower limit of the change rate expressed as MFR2 / MFR1, but values ​​of 0.0001 or higher are examples, with 0.001 or higher being preferred and 0.002 or higher being more preferred. The upper limit is set to 0.085 or lower, with 0.080 or lower being preferred, 0.070 or lower being more preferred, and 0.060 or lower being even more preferred. When the change rate expressed as MFR2 / MFR1 falls within the above preferred range, PAS tends to exhibit even greater mechanical strength and heat and humidity resistance when melt-kneaded with other resins or inorganic fillers to form a compound, making it particularly suitable for applications requiring heat and humidity resistance. In this invention, the rate of change expressed as MFR2 / MFR1 is determined by first measuring the melt flow rate of PAS in accordance with ASTM-D1238-70 to determine MFR1, then measuring the melt flow rate of a mixture obtained by mixing 1 g of PAS and 0.01 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (KBM-303, manufactured by Shin-Etsu Silicone) using a mortar and pestle to determine MFR2, and finally calculating MFR2 / MFR1.

[0108] Furthermore, the PAS used in this invention tends to have a cooling crystallization temperature of 210°C to 250°C. Because the PAS used in this invention tends to have higher crystallinity compared to general PAS, it is particularly preferable to use it in resin injection molding applications. Generally, in injection molding, it is known that crystallization is promoted the slower the cooling rate in the cooling crystallization temperature range during the cooling and solidification process from the molten state. Therefore, for resins with low crystallinity, the mold temperature is often set higher to prevent the cooling rate from becoming too fast. However, because the PAS obtained by the method of this invention tends to have high crystallinity, crystallization proceeds sufficiently even at relatively low mold temperatures, making it possible to efficiently mold the PAS. The cooling crystallization temperature of the PAS obtained by the preferred method of this invention varies depending on the polymerization and washing conditions, but the lower limit tends to be 210°C or higher, with a greater tendency to be 215°C or higher. Also, the upper limit tends to be 250°C or lower, with a greater tendency to be 240°C or lower.

[0109] (B) Glass fiber The polyarylene sulfide resin composition of the present invention comprises at least 10 to 200 parts by weight of (B) glass fibers per 100 parts by weight of (A) polyarylene sulfide. A more preferable lower limit for the amount of (B) glass fibers is 30 parts by weight or more, and 50 parts by weight or more is preferable from the viewpoint of obtaining higher strength. A preferable upper limit for the amount of (B) glass fibers is 150 parts by weight or less, and 130 parts by weight or less is preferable from the viewpoint of suppressing embrittlement.

[0110] The (B) glass fibers used in the present invention are preferably treated with a consolidating agent or a surface treatment agent. Examples of consolidating agents or surface treatment agents include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds, with epoxy compounds having a high epoxy content being particularly preferred from the viewpoint of improving the moisture and heat resistance of the reinforcing fibers.

[0111] There are no particular restrictions on the cross-sectional shape of the (B) glass fiber used in the present invention, but in addition to the general round shape, flattened, cocoon-shaped, oblong, elliptical, semicircular or arc-shaped, rectangular or similar cross-sectional shapes are preferably exemplified in that they improve the warping of the molded product, and a flattened cross-sectional shape is particularly preferred.

[0112] The glass fibers used in the present invention (B) have a round cross-sectional shape (hereinafter sometimes abbreviated as round glass fibers), and their fiber diameter is preferably 4 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more. When the fiber diameter is within the above preferred range, the glass fibers are not prone to breakage during melt kneading. The upper limit of the fiber diameter is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. As the fiber diameter decreases, the number of glass fibers per unit weight increases, and the reinforcing effect becomes greater, which is preferable.

[0113] Furthermore, in the present invention, it is preferable that the (B) glass fibers are opened in the polyarylene sulfide resin composition. Here, "opened" means that the (B) glass fibers in the polyarylene sulfide resin composition are opened down to individual fibers, and specifically, the number of reinforcing fibers bundled in groups of 10 or more among the observed reinforcing fibers is 40% or less of the total number of reinforcing fibers.

[0114] In the present invention, (B) glass fibers with a round cross-sectional shape can be obtained, for example, from Nippon Electric Glass Co., Ltd. under the trade name T-760H.

[0115] The (B) glass fiber of the present invention may be a glass fiber having a flattened cross-sectional shape (hereinafter sometimes abbreviated as flattened glass fiber). Preferably, the flattened glass fiber has a ratio of the major axis (longest straight distance of the cross-section) to the minor axis (longest straight distance perpendicular to the major axis) in a cross-section perpendicular to the length direction (hereinafter sometimes referred to as the flattening ratio) of 1.3 to 10, more preferably 1.5 to 5, and even more preferably 1.5 to 4.

[0116] By having the ratio of the major diameter to the minor diameter be 1.3 or more, an effect against deformation can be obtained, and from the viewpoint of manufacturing the product, it is preferably 10 or less. Also, for the purpose of reducing the specific gravity, etc., hollow fibers can also be used as the glass fiber.

[0117] The cross-sectional area of the flat glass fiber used in the present invention is 2×10 -5 ~8×10 -3 mm 2 is preferable. More preferably, it is 8×10 -5 ~8×10 -3 mm 2 and even more preferably 8×10 -5 ~8×10 -4 mm 2 When the cross-sectional area of the flat glass fiber is within the above preferable range, while a sufficient reinforcing effect can be obtained, handling also becomes easy.

[0118] The length of the flat glass fiber is arbitrary, but in view of the balance between the mechanical properties of the molded product and deformation, in order to reduce the amount of deformation of the molded product, a shorter length is preferable, but from the aspect of mechanical strength, an average fiber length of at least 30 μm or more is preferable, and it is appropriately selected according to the required performance. Usually, 50~1,000 μm is preferable.

[0119] As commercially available products of the (B) glass fiber having a flat cross-section, for example, CSG3PA-830 can be obtained from Nitto Boseki Co., Ltd. Also, it can be obtained under the trade name of T-760FGF from Nippon Electric Glass Co., Ltd.

[0120] (C) Non-fibrous inorganic filler In the polyarylene sulfide resin composition of the present invention, as a preferable embodiment, (C) non-fibrous inorganic filler is blended in an amount of 10~250 parts by weight with respect to 100 parts by weight of (A) polyarylene sulfide. As the lower limit of the blending amount of the more preferable (C) non-fibrous inorganic filler, 30 parts by weight or more can be exemplified, and 50 parts by weight or more is preferable from the viewpoint of improving dimensional stability. As the upper limit of the blending amount of (C) non-fibrous inorganic filler, 200 parts by weight or less is preferable, and 150 parts by weight or less can be preferably exemplified from the viewpoint of suppressing embrittlement.

[0121] (C) Examples of non-fibrous inorganic fillers include fullerenes, talc, warlastenite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, silicates such as alumina silicate, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, silica, and graphite. These may be hollow, and it is also possible to use two or more of these inorganic fillers in combination. Furthermore, these inorganic fillers may be pre-treated with coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds before use. Among these, calcium carbonate, which disperses relatively well in PAS even at high concentrations, is a preferred example.

[0122] (D) Organosilane coupling agents having functional groups In the present invention, a preferred embodiment of the polyarylene sulfide resin composition may include, to improve mechanical strength, toughness, etc., 0.1 to 10 parts by weight of an organic silane coupling agent having at least one functional group selected from the group consisting of epoxy groups, amino groups, and isocyanate groups (hereinafter sometimes abbreviated as "organosilane coupling agent having a (D) functional group") per 100 parts by weight of (A) polyarylene sulfide. By adding the organic silane coupling agent having a (D) functional group, it is possible to improve mechanical strength, toughness, etc. A more preferred lower limit for the amount of organic silane coupling agent having a (D) functional group is 0.2 parts by weight or more, and from the viewpoint of obtaining a sufficient mechanical strength improvement effect, it is even more preferred to include 0.4 parts by weight or more. A more preferred upper limit for the amount of organic silane coupling agent having a (D) functional group is 5 parts by weight or less, and from the viewpoint of suppressing excessive viscosity, it is even more preferred to include 2 parts by weight or less.

[0123] Specific examples of organosilane coupling agents having such (D) functional group include epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; isocyanate group-containing alkoxysilane compounds such as γ-isocyanatetopropyltriethoxysilane, γ-isocyanatetopropyltrimethoxysilane, γ-isocyanatetopropylmethyldimethoxysilane, γ-isocyanatetopropylmethyldiethoxysilane, γ-isocyanatetopropylethyldimethoxysilane, γ-isocyanatetopropylethyldiethoxysilane, and γ-isocyanatetopropyltrichlorosilane; and amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Among organosilane coupling agents having epoxy groups, γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane are more preferred from the viewpoint of exhibiting superior mechanical strength and resistance to humid and heat. (D) Comparing the functional groups of organosilane coupling agents having functional groups, organosilane coupling agents having at least one selected from amino groups and isocyanate groups are preferred from the viewpoint of exhibiting superior mechanical strength and resistance to humid and heat compared to organosilane coupling agents having epoxy groups. (D) It is preferable to exclude 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane having epoxy groups from the organosilane coupling agents having functional groups.

[0124] There are no particular limitations on the method for producing the PAS resin composition of the present invention, but typical examples include mixing each raw material and supplying it to a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll for kneading.

[0125] In particular, a method of melt-kneading using a twin-screw extruder in which the ratio L / D of screw length L to screw diameter D is 10 or more and 100 or less is preferred. An L / D of 20 or more and 100 or less is more preferred, and 30 or more and 100 or less is even more preferred.

[0126] The PAS resin composition obtained in this manner has improved mechanical strength and excellent moldability due to the low amount of gas generated during melting. Specifically, the preferred heat loss of the PAS resin composition of the present invention is 0.35% by weight or less, more preferably 0.30% by weight or less, and even more preferably 0.25% by weight or less. The heat loss was calculated by weighing 10g of the PAS composition pellets of the present invention into an aluminum cup that had been preheated at 330°C for 3 hours, heating it in a hot air dryer at 320°C for 2 hours, then removing it and cooling it in a desiccator containing a desiccant, weighing it, and calculating the weight loss as a percentage of the weight before heating.

[0127] The PAS resin composition of the present invention can be used in various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, but is particularly suitable for injection molding applications.

[0128] The PAS resin composition of the present invention is particularly useful as a fluid piping component through which a water-based fluid flows, due to its excellent mechanical strength and resistance to humid and heat. A water-based fluid is a liquid containing 30% by weight or more water, and examples include room temperature water, hot water heated from room temperature to 100°C, and coolant obtained by diluting ethylene glycol, the main component of automotive coolant known as long-life coolant, with 30% by weight or more water. More specific examples of piping components include fittings, valves, servos, sensors, pipes, and pumps through which automotive coolant or hot water from water heaters flows. The liquid flowing through the piping components may be an antifreeze containing water as the main component, along with alcohols, glycols, glycerin, etc., and its type and concentration are not particularly limited.

[0129] Other applicable uses for molded articles made from the PAS resin composition of the present invention include, for example, electrical and electronic components such as sensors, LED lamps, consumer connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, semiconductors, liquid crystal displays, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related parts; as well as household and office electrical product parts such as VTR parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio, laser discs (registered trademark), and compact discs; lighting parts, refrigerator parts, air conditioner parts, typewriter parts, and word processor parts.Other parts include office computer-related parts, telephone-related parts, facsimile-related parts, photocopier-related parts, cleaning jigs, motor parts, lighters, typewriters, and other mechanical parts; optical instruments such as microscopes, binoculars, cameras, and watches; precision machinery-related parts; valve alternator terminals, alternator connectors, IC regulators, light dew potentiometer bases, exhaust gas valves and other various valves; various pipes for fuel, exhaust, and intake systems; air intake nozzle snorkels, intake manifolds, fuel pumps, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, throttle position sensors, crankshaft position sensors, and air Examples of applications include various automotive and vehicle-related parts such as flow meters, brake pad wear sensors, thermostat bases for air conditioners, heating hot air flow control valves, brush holders for radiator motors, water pump impellers, turbine vanes, wiper motor related parts, distributors, starter switches, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioning panel switch boards, coils for fuel-related solenoid valves, fuse connectors, horn terminals, electrical component insulating plates, stepper motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition system cases, vehicle speed sensors, and cable liners.

[0130] In particular, molded articles made from the resin composition of the present invention are suitable for plumbing components for water-related systems, such as toilet-related parts, water heater-related parts, bath-related parts, pump-related parts, and water meter-related parts. Specifically, examples include water faucet valves, mixing faucets, mixing valves, pump parts, pipe joints, fittings (elbows, tees, sockets, etc.), water volume control valves, pressure reducing valves, relief valves, solenoid valves, three-way valves, thermostatic valves, water temperature sensors, water volume sensors, bathtub adapters, and water meter housings. [Examples]

[0131] The present invention will be further described with reference to the following examples, but the present invention is not limited to the descriptions in these examples.

[0132] [Evaluation method for PAS manufactured using the example] (1) Method for measuring molecular weight and evaluating molecular weight distribution shape The molecular weight of PAS was measured using gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). The sample was prepared by adding 5 g of 1-chloronaphthalene to 5 mg of PAS, heating to 250°C to dissolve, cooling the solution to room temperature to form a slurry, and filtering it through a membrane filter (pore size 0.1 μm). The prepared sample was then subjected to GPC measurement under the following conditions, and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) were calculated in polystyrene equivalents. Device: SSC-7110, manufactured by Senshu Kagaku Co., Ltd. Column name: Shodex UT806M×2 Eluent: 1-Chloronaphthalene Detector: Differential refractive index detector Column temperature: 210℃ Pre-temperature bath temperature: 250℃ Pump constant temperature bath temperature: 50℃ Detector temperature: 210℃ Flow rate: 1.0mL / min Sample injection volume: 300 μL.

[0133] To evaluate the molecular weight distribution shape of PAS, the concentration fractions obtained from the chromatogram by the GPC measurement described above were sequentially accumulated, and the molecular weight (logarithmic value) was plotted on the x-axis and the accumulated value of the concentration fraction on the y-axis to create an integral molecular weight distribution curve. The range of molecular weight values ​​from 100 to 10,000 on the x-axis of this integral molecular weight distribution curve was then extracted, and the cumulative integral value from molecular weight 100 to 4,000 was calculated, with the cumulative integral value from molecular weight 100 to 10,000 set to 100, and this value was defined as the molecular weight distribution shape.

[0134] (2) Melt Flow Rate (MFR) The melt flow rate of PAS was evaluated by measuring the melt flow rate (resin discharge volume per 10 minutes: g / 10min) in accordance with ASTM-D1238-70 and comparing the values. Equipment: Melt indexer manufactured by Toyo Seiki Seisakusho Co., Ltd. (using an orifice with a length of 8.0 mm and a hole diameter of 2.095 mm) Load: 5,000g Sample amount: 7g Temperature: 315.5℃ (melting time: 5 minutes).

[0135] (3) Rate of change expressed as MFR2 / MFR1 When the melt flow rate of PAS is defined as MFR1, and the melt flow rate after mixing PAS and an epoxysilane coupling agent in a weight ratio of 100:1 and heating at 315.5°C for 5 minutes is defined as MFR2, the rate of change expressed as MFR2 / MFR1 is calculated by first determining MFR1 by measuring the melt flow rate of PAS in accordance with ASTM-D1238-70, then mixing 1g of PAS and 0.01g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (KBM-303, manufactured by Shin-Etsu Chemical Co., Ltd.) using a mortar and pestle, heating the mixture at 315.5°C for 5 minutes, measuring the melt flow rate to determine MFR2, and then calculating MFR2 / MFR1.

[0136] (4)Residue amount A 1 μm pore-size PTFE membrane filter, pre-weighed and fitted with a pneumatic cap and collection funnel, was placed in a SUS test tube manufactured by Senshu Kagaku Co., Ltd. 100 mg of PAS (press-filmed to approximately 80 μm thickness) and 2 g of 1-chloronaphthalene were weighed into the filter and then sealed. This was then inserted into a Senshu Kagaku SSC-9300 high-temperature filtration device and heated at 250°C for 5 minutes with shaking to dissolve the PAS in 1-chloronaphthalene. A 20 mL syringe containing air was connected to the pneumatic cap, and the piston was pushed out to filter the solution through the membrane filter. The membrane filter was removed, vacuum-dried at 150°C for 1 hour, and then weighed. The difference in membrane filter weight before and after filtration was defined as the residue amount (weight %).

[0137] (A)PAS [Reference Example 1] Preparation of PAS:A1 A distillation apparatus and an alkaline trap were connected to an autoclave equipped with a stirrer and a bottom drain valve. 11.6 kg (100 mol) of 48.3% sodium hydrosulfide aqueous solution, 8.25 kg (101 mol) of 48.9% sodium hydroxide aqueous solution, 16.4 kg (165 mol) of N-methyl-2-pyrrolidone, and 1.56 kg (19.0 mol) of sodium acetate were charged into the reaction vessel, and the reaction vessel was thoroughly purged with nitrogen.

[0138] The mixture was gradually heated to 237°C over 3 hours in an autoclave with nitrogen flowing through it and stirring at 60 rpm to remove the liquid, yielding 12 kg of distillate. Gas chromatography analysis of this distillate revealed that it consisted of 10.2 kg of water and 1.8 kg of N-methyl-2-pyrrolidone. At this stage, 20 g (1 mole) of water and 14.6 kg of N-methyl-2-pyrrolidone remained in the reaction system. Additionally, 0.675 moles of hydrogen sulfide were released from the reaction system during the dehydration process.

[0139] Next, after cooling the autoclave to below 170°C, 15 kg (101.8 mol) of p-dichlorobenzene and 14.6 kg (147 mol) of N-methyl-2-pyrrolidone were added. The reaction vessel was then thoroughly purged with nitrogen again and sealed. As a result, the amount of dihalogenated aromatic compound used in the mixture was 102.5 mol per mol of sulfur (the sulfidating agent). The internal temperature was reduced to 130°C during the charging process.

[0140] Next, the temperature inside the reaction vessel was raised from 130°C to 275°C over approximately 2 hours while stirring at 250 rpm, and then the reaction was maintained at 275°C for 70 minutes. The pressure inside the system was 1.10 MPa.

[0141] (Process 1) After the reaction was complete, the withdrawal valve at the bottom of the autoclave was opened, and the reaction solution, at 1.10 MPa and 275°C, was flushed over 15 minutes into a stirrer-equipped vessel (with distillation apparatus) heated to 220°C at atmospheric pressure. Then, while stirring, the vessel was maintained at 240°C to distill off N-methyl-2-pyrrolidone, after which heating was stopped and the vessel was cooled, and the solids in the vessel were recovered.

[0142] (Process 2) The solid obtained in step 1 was placed in another container equipped with a stirrer, 108 kg of deionized water was added, and the mixture was stirred at 70°C for 30 minutes. The mixture was then filtered using a pressure filter to obtain the cake.

[0143] The cake obtained above was placed in a pressure-resistant container equipped with a stirrer, 128 kg of deionized water was added, and after purging with nitrogen, the temperature was raised to 192°C and stirred for 30 minutes. After that, the container was cooled, the slurry was removed, and filtered through a pressure filter to obtain the cake.

[0144] The cake obtained above was again placed in a container with a stirrer, 108 kg of deionized water was added, and the mixture was stirred at 70°C for 30 minutes. This process of filtering the mixture through a pressure filter to obtain cake was repeated three times.

[0145] The resulting moist cake was dried under a nitrogen stream at 120°C for 3 hours to obtain dried polyarylene sulfide (PAS). The moisture content of the obtained dried PAS was measured by the Karl Fischer method according to the method specified in JIS K 7251 and was found to be 0.1% by weight.

[0146] (Step 3) The dried PAS obtained in step 2 was placed in a container with a stirrer, 54 kg of N-methyl-2-pyrrolidone (weight bath ratio of 5 to PAS) was added, and the mixture was stirred at 30°C for 20 minutes. The mixture was then filtered using a pressure filter to obtain the cake.

[0147] (Step 4) The moist cake obtained in step 3 (containing 10.8 kg as PAS) was heated at 200°C for 20 hours while flowing nitrogen at a flow rate of 4 L / min (0.4 L / min per kg of polyarylene sulfide) to remove NMP and obtain dry PAS.

[0148] Analysis of the obtained PAS:A1 revealed a weight-average molecular weight (Mw) of 40,000. The cumulative integral value from molecular weight 100 to 4,000 (with the cumulative integral value from 100 to 10,000 set to 100) was calculated to be 52. Furthermore, MFR1 was 637 g / 10 min and MFR2 was 32 g / 10 min, with a change rate expressed as MFR2 / MFR1 of 0.050. The residue after dissolution in 1-chloronaphthalene solvent was 0.6% by weight.

[0149] [Reference Example 2] Preparation of PAS:A2 PAS:A1 obtained in Reference Example 1 was subjected to thermal oxidation treatment under conditions of 2% oxygen concentration, 220°C, and 12 hours. Analysis of the obtained PAS:A2 revealed that the weight-average molecular weight Mw was 45,000, and the cumulative integral value from molecular weight 100 to 4,000 (with the cumulative integral value from molecular weight 100 to 10,000 set to 100) was calculated to be 51. Furthermore, the MFR1 was 450 g / 10 min and the MFR2 was 25 g / 10 min, and the rate of change expressed as MFR2 / MFR1 was 0.055. The amount of residue after dissolution in 1-chloronaphthalene solvent was 1.8% by weight.

[0150] [Reference Example 3] Preparation of PAS:A3 PAS:A1 obtained in Reference Example 1 was subjected to thermal oxidation treatment at an oxygen concentration of 11% at 220°C for 12 hours. Analysis of the obtained PAS:A3 revealed that the weight-average molecular weight Mw was 49,000, and the cumulative integral value from molecular weight 100 to 4,000, with the cumulative integral value from molecular weight 100 to 10,000 set to 100, was calculated to be 49. Furthermore, the MFR1 was 100 g / 10 min and the MFR2 was 7.5 g / 10 min, and the rate of change expressed as MFR2 / MFR1 was 0.071. The amount of residue after dissolution in 1-chloronaphthalene solvent was 13% by weight.

[0151] [Reference Example 4] Preparation of PAS:A'1 PAS was manufactured in the same manner as in Reference Example 1, except that step 3 of Reference Example 1 was not performed. Analysis of the obtained PAS:A'1 revealed that the weight-average molecular weight Mw was 39,000, and the cumulative integral value from molecular weight 100 to 4,000, with the cumulative integral value from molecular weight 100 to 10,000 set to 100, was calculated to be 54. The MFR1 was 657 g / 10 min, and the MFR2 was 41 g / 10 min, and the rate of change expressed as MFR2 / MFR1 was 0.062. The amount of residue after dissolution in 1-chloronaphthalene solvent was 0.6% by weight.

[0152] [Reference Example 5] Preparation of PAS:A'2 Except for not performing step 3 of Reference Example 1, PAS was obtained in the same manner as in Reference Example 1, and then thermal oxidation treatment was performed under the conditions of 2% oxygen concentration, 220°C, and 12 hours. Analysis of the obtained PAS:A'2 revealed that the weight-average molecular weight Mw was 44,000, and the cumulative integral value from molecular weight 100 to 4,000, with the cumulative integral value from molecular weight 100 to 10,000 set to 100, was calculated to be 54. Furthermore, the MFR1 was 440 g / 10 min and the MFR2 was 30 g / 10 min, and the rate of change expressed as MFR2 / MFR1 was 0.068. The amount of residue after dissolution in 1-chloronaphthalene solvent was 1.9% by weight.

[0153] [Reference Example 6] Preparation of PAS:A'3 After the reaction in Reference Example 1 was completed, step 3 was repeated three times without performing step 1, and then step 2 of Reference Example 1 was performed to produce PAS. Analysis of the obtained PAS:A'3 revealed that the weight-average molecular weight Mw was 42,000, and the cumulative integral value from molecular weight 100 to 4,000, with the cumulative integral value from molecular weight 100 to 10,000 set to 100, was calculated to be 42. Furthermore, the MFR1 was 580 g / 10 min and the MFR2 was 72 g / 10 min, and the rate of change expressed as MFR2 / MFR1 was 0.124. The amount of residue after dissolution in 1-chloronaphthalene solvent was 0.5% by weight.

[0154] (B) Glass fiber B1: T-760H (Chopped Strand Glass Fiber) manufactured by Nippon Electric Glass Co., Ltd. (C) Non-fibrous inorganic filler C1: KSS-1000 (heavy calcium carbonate) manufactured by Dowa Calfine Co., Ltd. (D) Organosilane coupling agents having functional groups D1: SH6040 (γ-glycidoxypropyltrimethoxysilane) manufactured by Toray Dow Co., Ltd. D2: KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. D3: KBE-903 (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. D4: KBE-9007N (3-isocyanate-propyltriethoxysilane), manufactured by Shin-Etsu Chemical Co., Ltd.

[0155] [Evaluation method for PAS composition produced in the example] (1) Tensile strength The PAS resin composition pellets of the present invention were dried at 130°C for 3 hours using a hot air dryer. Then, they were supplied to a Sumitomo Heavy Industries injection molding machine (SE-50D) set to a cylinder temperature of 320°C and a mold temperature of 145°C. Using a mold of type A1 test specimen shape as specified in ISO 20753 (2008), injection molding was performed under conditions where the average speed of the molten resin passing through the cross-sectional area of ​​the central parallel section was 400 ± 50 mm / s to obtain a test specimen for evaluation. After conditioning this test specimen at 23°C and 50% relative humidity for 16 hours, the tensile strength was measured in accordance with ISO 527-1,2, under conditions of a grip distance of 114 mm and a test speed of 5 mm / s.

[0156] (2) Bending strength The PAS resin composition pellets of the present invention were dried at 130°C for 3 hours using a hot air dryer. The pellets were then supplied to a Sumitomo Heavy Industries, Ltd. injection molding machine (SE-50D) set to a cylinder temperature of 320°C and a mold temperature of 145°C. Injection molding was performed using a mold of type A1 specimen shape as specified in ISO 20753 (2008), under conditions where the average velocity of the molten resin passing through the cross-sectional area of ​​the central parallel section was 400 ± 50 mm / s, thereby obtaining a test specimen. The central parallel section of this specimen was cut out to obtain a type B2 specimen. This specimen was conditioned for 16 hours at 23°C and 50% relative humidity. The bending strength was then measured according to the ISO 178 (2010) method, with a span of 64 mm, a test speed of 2 mm / s, and a temperature of 23°C.

[0157] (3) Weld strength The PAS resin composition pellets of the present invention were dried at 130°C for 3 hours using a hot air dryer. Then, they were supplied to a Sumitomo Heavy Industries, Ltd. injection molding machine (SE-50D) set to a cylinder temperature of 320°C and a mold temperature of 145°C. Injection molding was performed using a mold with a weld specimen shape compliant with Type A1 as specified in ISO 20753 (2008) to obtain test specimens. These test specimens were conditioned for 16 hours at 23°C and 50% relative humidity, and then tensile strength measurements were performed in accordance with ISO 527-1,2, with a grip distance of 114 mm and a test speed of 5 mm / s.

[0158] (4) Tensile strength (moisture and heat resistance) after PCT treatment Type A1 test specimens, as defined in ISO 20753 (2008), obtained by injection molding under the same conditions as in item (1), were subjected to PCT treatment using a Dabay Especk Advanced Accelerated Life Testing System (EHS-221M) at 121°C, 100% RH, 2 atm, and 100 hours, and the tensile strength of the treated specimens was measured.

[0159] (5) Spiral flow length Using a 1mm thick (1mmt) spiral flow mold, molding was performed under the following conditions: cylinder temperature 320°C, mold temperature 140°C, injection speed 230mm / sec, injection pressure 98MPa, injection time 5sec, and cooling time 15sec. Flow length (unit: mm) was measured (injection molding machine used: SE-30D manufactured by Sumitomo Heavy Industries, Ltd.). A larger value indicates superior flowability.

[0160] (6)Heating loss Ten g of PAS resin composition pellets of the present invention were weighed into an aluminum cup that had been preheated at 330°C for 3 hours, and then heated in a hot air dryer at 320°C for 2 hours. After that, the cup was removed and cooled in a desiccator containing a desiccant, and then weighed. The weight loss due to heating was calculated as the weight percentage of the weight reduction before and after heating relative to the weight before heating.

[0161] (7) Cooling down crystallization temperature Approximately 10 mg of pellets of the PAS resin composition of the present invention were weighed, and the crystallization peak (exothermic peak) temperature was measured using a PerkinElmer differential scanning calorimeter DSC-7 when the temperature was increased at a rate of 20°C / min, held at 340°C for 5 minutes, and then cooled at a rate of 20°C / min.

[0162] [Examples 1-8 and Comparative Examples 1-6] Using a twin-screw extruder (TEM-26SS, manufactured by Toshiba Machine Co., Ltd., L / D=64.6) with a 26 mm diameter intermediate additive port and a cylinder temperature set to 310°C, (A) PAS, (C) inorganic filler, and (D) silane coupling agent were dry-blended in the weight ratios shown in Tables 1 and 2, and added from the upstream extruder raw material supply port to a molten state. (B) glass fibers were then supplied from the intermediate additive port in the weight ratios shown in Tables 1 and 2, and the mixture was melt-kneaded under conditions of a rotational speed of 300 rpm and a total discharge rate of 40 kg / hour to obtain resin composition pellets. The obtained resin composition pellets were subjected to injection molding as described above to obtain various molded products, and then the tensile strength, flexural strength, weld strength, and tensile strength after PCT treatment were evaluated. In addition, the spiral flow length, heat loss, and cooling crystallization temperature were evaluated using the method described above. The results are shown in Tables 1 and 2.

[0163] [Table 1]

[0164] [Table 2]

[0165] The results of Examples 1-8 and Comparative Examples 1-6 will be explained in comparison.

[0166] Example 1 is compared with Comparative Example 1, Examples 2 and 3 with Comparative Examples 2 and 3, Examples 7 with Comparative Examples 4 and 5, and Example 8 with Comparative Example 6. In all examples, the polyarylene sulfide is such that when the cumulative integral value from molecular weight 100 to 10,000 in the molecular weight distribution curve is set to 100, the cumulative integral value at molecular weight 4,000 is between 48 and 53. When the melt flow rate of the polyarylene sulfide is set to MFR1, and the melt flow rate after mixing the polyarylene sulfide and epoxy silane coupling agent in a weight ratio of 100:1 and heating at 315.5°C for 5 minutes is set to MFR2, the change rate expressed as MFR2 / MFR1 is 0.085 or less. By using PAS, mechanical strengths such as tensile strength, bending strength, and weld strength were improved compared to the corresponding comparative examples. Furthermore, the tensile strength after PCT treatment was also maintained at a higher level in the examples compared to the comparative examples, indicating improved resistance to humid heat. Since the spiral flow length is almost the same in the example and the comparative example, thin-wall formability is maintained. In addition, the example also achieves the effect of reducing mold contamination during continuous molding because the heat loss is reduced. Furthermore, the cooling crystallization temperature of the example is higher than that of the comparative example, and the crystallization rate is faster, so it was found to have excellent high-cycle formability.

[0167] Comparing Example 7 with Comparative Example 5, while Comparative Example 5 exhibited excellent tensile strength, flexural strength, weld strength, and heat loss, similar to Example 7, its tensile strength after PCT treatment was inferior to that of the example, and its spiral flow length was also shorter, resulting in poorer thin-wall formability. [Industrial applicability]

[0168] The PAS composition of the present invention exhibits excellent mechanical strength and resistance to moisture and heat, as well as improved moldability, making it suitable for use in various molded products such as automotive parts and electrical and electronic components. It is particularly suitable as a fluid piping component with water as its main component.

Claims

1. A polyarylene sulfide resin composition comprising 100 parts by weight of (A) polyarylene sulfide and 10 to 200 parts by weight of (B) glass fiber, wherein the (A) polyarylene sulfide has a cumulative integral value of 48 or more and 53 or less at a molecular weight of 4,000 when the cumulative integral value from molecular weight 100 to 10,000 in the molecular weight distribution curve is set to 100, and when the melt flow rate of the (A) polyarylene sulfide is set to MFR1, and the melt flow rate after mixing the (A) polyarylene sulfide and an epoxysilane coupling agent in a weight ratio of 100:1 and heating at 315.5°C for 5 minutes is set to MFR2, the rate of change expressed as MFR2 / MFR1 is 0.085 or less.

2. The polyarylene sulfide resin composition according to claim 1, wherein the polyarylene sulfide resin composition is further compounded with (A) polyarylene sulfide in an amount of 10 to 250 parts by weight of (C) non-fibrous inorganic filler.

3. The polyarylene sulfide resin composition according to claim 1, wherein the polyarylene sulfide resin composition is further enriched with (A) 100 parts by weight of polyarylene sulfide, and (D) 0.1 to 10 parts by weight of an organosilane coupling agent having at least one functional group selected from the group consisting of epoxy groups, amino groups, and isocyanate groups.

4. The polyarylene sulfide resin composition according to claim 3, wherein the functional group of the (D) organosilane coupling agent is an amino group or an isocyanate group.

5. The polyarylene sulfide resin composition according to any one of claims 1 to 4, wherein the (A) polyarylene sulfide has a crosslinked structure.

6. The polyarylene sulfide resin composition according to claim 5, wherein the (A) polyarylene sulfide having a crosslinked structure is dissolved in 20 times its weight of 1-chloronaphthalene at 250°C for 5 minutes, and the amount of residue when filtered by hot pressure through a PTFE membrane filter with a pore size of 1 μm is 4.0% by weight or less.

7. A molded article comprising the polyarylene sulfide resin composition according to any one of claims 1 to 4.

8. The molded article according to claim 7, wherein the molded article is a fluid piping component through which a fluid mainly composed of water flows.

Images