Polyarylene sulfide resin composition and method for improving moldability of polyarylene sulfide resin

Abstract

To provide: a polyarylene sulfide resin composition which has not only excellent moldability, but also excellent mechanical properties, surface appearance, and heat resistance; and a method for improving the moldability of a polyarylene sulfide resin without reducing the surface appearance, heat resistance, or mechanical properties such as strength and impact properties.SOLUTION: The present invention discloses a polyarylene sulfide resin composition including polyarylene sulfide and zinc dialkyldithiophosphate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyarylene sulfide resin composition and a method for improving the moldability of a polyarylene sulfide resin. [Background technology]

[0002] Polyarylene sulfide is an engineering plastic that has excellent heat resistance, rigidity, dimensional stability, and flame retardancy, and is widely used as a substitute for metal materials in fields such as electrical and electronics, machinery, and automobiles. For example, polyarylene sulfide is used as a material for water tanks used to cool engines in engine compartments. Therefore, materials used in these applications are required to have not only excellent heat resistance and mechanical properties, but also excellent surface appearance. A representative polyarylene sulfide resin is polyphenylene sulfide resin.

[0003] In addition, polyarylene sulfide is also required to have high moldability because it is used as a substitute for metals such as aluminum and zinc that are processed by die-casting. However, when an additive is added to polyarylene sulfide to improve moldability, there is a problem that physical properties other than moldability, such as mechanical properties and heat resistance, are deteriorated.

[0004] It is known to add various additives to polyarylene sulfide resins. For example, JP 2016-34999 A describes a polyarylene sulfide resin composition to which composite particles of a conductive filler and an inorganic lubricant are added to impart uniform conductivity.

[0005] However, no additives have been known to date that have the effect of improving moldability while preventing or improving mechanical properties such as impact resistance and heat resistance, and therefore, there has been a problem of insufficient fluidity when injection molding conventional polyarylene sulfide resins. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-34999 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there has been a demand for a polyarylene sulfide resin composition that is more moldable than conventional polyarylene sulfide resins, does not reduce mechanical properties such as strength and impact resistance, and is excellent in surface appearance and heat resistance, as well as a method for improving the moldability of polyarylene sulfide resins.

[0008] The present invention has been made to solve the problems of the above-mentioned conventional techniques, and an object of the present invention is to provide a polyarylene sulfide resin composition that is excellent not only in moldability but also in mechanical properties, surface appearance, and heat resistance, and a method for improving the moldability of a polyarylene sulfide resin without reducing mechanical properties such as strength and impact resistance, surface appearance, and heat resistance. [Means for solving the problem]

[0009] As a result of intensive research into the above-mentioned problems, the present inventors unexpectedly discovered that the use of zinc dialkyldithiophosphate as an additive can improve the moldability of polyarylene sulfide resin, and also result in excellent mechanical properties such as strength and impact resistance, surface appearance, and heat resistance, and thus arrived at the present invention.

[0010] The objects of the present invention are achieved by a polyarylene sulfide resin composition comprising a polyarylene sulfide and a zinc dialkyldithiophosphate.

[0011] The alkyl group of the zinc dialkyldithiophosphate preferably has 5 to 20 carbon atoms.

[0012] The zinc dialkyldithiophosphate is preferably contained in an amount of 0.001 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyarylene sulfide resin.

[0013] The polyarylene sulfide is preferably polyphenylene sulfide.

[0014] The polyarylene sulfide is preferably contained in an amount of 40% by mass or more and 99% by mass or less of the polyarylene sulfide resin composition.

[0015] The present invention also relates to a method for improving the moldability of a polyarylene sulfide resin, which comprises adding a zinc dialkyldithiophosphate to the polyarylene sulfide resin.

[0016] In the above method, the alkyl group of the zinc dialkyldithiophosphate preferably has 5 to 20 carbon atoms.

[0017] In the above method, the zinc dialkyldithiophosphate is preferably added in an amount of 0.001 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the polyarylene sulfide resin.

[0018] In the above method, the polyarylene sulfide is preferably polyphenylene sulfide. [Effects of the Invention]

[0019] According to the present invention, the use of zinc dialkyldithiophosphate can improve the moldability of polyarylene sulfide resins. Furthermore, since the polyarylene sulfide resins not only have excellent moldability but also excellent mechanical properties such as strength and impact resistance, as well as heat resistance, they can be used in high-temperature environments such as automobile engines. Furthermore, since the surface appearance is also excellent, the polyarylene sulfide resins of the present invention can be used not only for internal structures but also for applications where they are directly visible.

[0020] Furthermore, the present invention has the advantage that, compared to conventional polyarylene sulfide resin compositions, the addition of additives does not impair mechanical properties and surface appearance. Therefore, the present invention not only improves moldability, but also has the advantageous property of maintaining or improving other physical properties to those without additives. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described in detail below. However, it is not intended that the present invention be limited to a specific embodiment, and various modifications can be made within the scope of the technical concept of the present invention.

[0022] The polyarylene sulfide resin composition of the present invention contains, as essential components, polyarylene sulfide and zinc dialkyldithiophosphate.

[0023] (Polyarylene sulfide) The polyarylene sulfide contains a structure in which an aromatic ring and a sulfur atom are bonded as a repeating unit. More specifically, the polyarylene sulfide preferably contains a p-phenylene sulfide unit as a basic repeating unit, but may contain repeating units such as an m-phenylene sulfide unit, an o-phenylene sulfide unit, a p,p'-diphenylene ketone sulfide unit, a p,p'-diphenylene sulfone sulfide unit, a p,p'-biphenylene sulfide unit, a p,p'-diphenylene ether sulfide unit, a p,p'-diphenylene methylene sulfide unit, a p,p'-diphenylene cumenyl sulfide unit, and various naphthylene sulfide units.

[0024] The polyarylene sulfide is preferably polyphenylene sulfide, and in particular may be polyphenylene sulfide containing a repeating unit of the following chemical formula 1:

[0025] [ka]

[0026] In the formula, each R1 is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, an amino group, and a phenyl group; m is an integer of 0 to 4.

[0027] Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and examples of alkoxy groups having 1 to 6 carbon atoms include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyloxy groups. The alkyl groups having 1 to 6 carbon atoms and the alkoxy groups having 1 to 6 carbon atoms may be linear or branched. Furthermore, the alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, nitro groups, amino groups, and phenyl groups of R1 may be substituted with a substituent selected from the group consisting of halogens, hydroxyl groups, alkyl groups, alkoxy groups, and aryl groups.

[0028] In Chemical Formula 1, the sulfur atom in the aromatic ring may be bonded at any of the ortho, meta, and para positions, but is preferably bonded at the para position because it exhibits better heat resistance and crystallinity.

[0029] The number average molecular weight (Mn) of the polyarylene sulfide is 1,000 to 1,000,000, preferably 5,000 to 100,000, and more preferably 10,000 to 50,0000. The number average molecular weight of the polyarylene sulfide can be measured by high-temperature GPC and is expressed as a value converted into standard polystyrene. Nine types of molecular weights of polystyrene standards can be used: 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000,000.

[0030] The melt flow rate (MFR) of the polyarylene sulfide may be 10 to 10,000 g / 10 min, preferably 10 to 1,000 g / 10 min, measured at 315° C. and a pressure of 2.16 kg. A polyarylene sulfide resin having a melt flow rate in the above range can exhibit excellent processability and fluidity.

[0031] The polyarylene sulfide may have a melting temperature (Tm) of 210 to 350° C. and a crystallization temperature (Tc) of 190 to 330° C., and preferably has a Tm of 220 to 330° C. and a Tc of 200 to 310° C. The melting temperature and crystallization temperature of the polyarylene sulfide may be measured using a differential scanning calorimeter (DSC).

[0032] The polyarylene sulfide may be a straight-chain polyarylene sulfide resin or an oxidatively crosslinked polyarylene sulfide resin, but it is preferable to use a straight-chain polyarylene sulfide resin.

[0033] The polyarylene sulfide that can be used is, for example, one produced by a method of subjecting a general dihalogeno aromatic compound and a sulfur source to a condensation polymerization reaction in an organic polar solvent.

[0034] The polyarylene sulfide is contained in an amount of 40% by mass or more and 99% by mass or less, preferably 45% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and most preferably 55% by mass or more and 80% by mass or less of the polyarylene sulfide resin composition.

[0035] (Zinc dialkyldithiophosphate) Zinc dialkyldithiophosphate is a compound represented by the following chemical formula 2.

[0036] [ka]

[0037] In the formula, R 21, R 22 , R 23 and R 24 are each independently an alkyl group having 5 to 20 carbon atoms.

[0038] That is, the alkyl group of the zinc dialkyldithiophosphate preferably has 5 to 20 carbon atoms, more preferably 8 to 20 carbon atoms, and most preferably 10 to 18 carbon atoms.

[0039] Examples of alkyl groups having 5 to 20 carbon atoms include, but are not limited to, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups. The alkyl groups having 5 to 20 carbon atoms may be linear or branched.

[0040] The zinc dialkyldithiophosphate is contained in an amount of 0.001 to 20 parts by mass, preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and most preferably 0.2 to 2 parts by mass, per 100 parts by mass of the polyarylene sulfide resin.

[0041] (Other ingredients) The polyarylene sulfide resin composition of the present invention may further contain a resin other than polyarylene as a resin. For example, the polyarylene sulfide resin composition may contain one or more thermoplastic resins such as polyolefin resins, polycarbonate resins, polyamide resins, polyester resins, polyacetal resins, modified polyphenylene ether resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene naphthalate resins, polyarylate resins, polyethersulfone resins, polyetherketone resins, polythioetherketone resins, polyetheretherketone resins, polysulfone resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyarylene resins, polybenzimidazole resins, polymethylpentene resins, polycyclohexylene-dimethylene-terephthalate resins, polystyrene resins, polyphenylene oxide resins, styrene-based resins, polymethacrylic resins, polyacrylic resins, polyethylenedifluoride resins, polyethylenetetrafluoride resins, polyketone resins, ABS resins, phenolic resins, urethane resins, nylon-based resins, silicone resins, and thermoplastic elastomers.

[0042] Furthermore, the polyarylene sulfide resin composition of the present invention may further contain one or more additives, such as a coupling agent, a fiber material, a filler, an impact resistance imparting agent, a reinforcing agent, a mold release agent, a colorant, an antioxidant, a heat stabilizer, an ultraviolet stabilizer, an ultraviolet absorber, a foaming agent, a flame retardant, a flame retardant aid, a rust inhibitor, a crystal nucleating agent, a plasticizer, a pigment, a dye, an antistatic agent, a foaming agent, and a lubricant other than zinc dialkyldithiophosphate, in order to improve the physical properties of the resin composition depending on the application.

[0043] The coupling agent is not particularly limited, but a silane-based or titanium-based coupling agent can be used. More specifically, epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, and γ Examples of such alkoxysilane compounds include isocyanato group-containing alkoxysilane compounds such as γ-isocyanatopropylethyldiethoxysilane and γ-isocyanatopropyltrichlorosilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane and γ-aminopropyltrimethoxysilane; and hydroxy group-containing alkoxysilane compounds such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane. Any one of these compounds or a mixture of two or more thereof can be used.

[0044] The coupling agent is contained in an amount of 10% by mass or less, preferably 0.01 to 5% by mass or less, of the polyarylene sulfide resin composition. When contained within the above range, the mechanical strength of the polyarylene sulfide resin composition can be improved, and the viscosity can be increased to impart excellent moldability.

[0045] The fiber material is not particularly limited, but a fiber-shaped material having an average fiber diameter of 1 to 50 μm and an average fiber length of 0.5 mm to 25 mm can be used. The fiber material may be an inorganic fiber material or an organic fiber material. Examples of inorganic fiber materials include glass fibers such as chopped strands, milled fibers, and roving; carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers; graphitized fibers; whisker materials such as silicon nitride whiskers, basic magnesium sulfate whiskers, barium titanate whiskers, potassium titanate whiskers, silicon carbide whiskers, boron whiskers, aluminum borate whiskers, and zinc oxide whiskers; metal fibers such as stainless steel fibers; and mineral fibers such as wollastonite, asbestos, sepiolite, slag fiber, zirconia, rock wool, ceramics, xonotlite, estodite, and gypsum. Examples of organic fiber materials include wholly aromatic polyamide fibers, phenolic resin fibers, and wholly aromatic polyester fibers, and any one or a mixture of two or more of these can be used. Preferably, the fiber material is an inorganic fiber material, and glass fiber is particularly preferred.

[0046] When glass fibers are used as the fiber material, the glass fibers are preferably alkali-free glass (E glass) or alkali-containing glass (C glass) containing 45 to 75% by weight of SiO2.

[0047] The fiber material may or may not be surface-treated, but it is preferable to use a surface-treated fiber material. The surface treatment agent used for the surface treatment of the fiber material is not particularly limited, but examples of usable surface treatment agents include coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds. The amount of surface treatment agent used relative to the mass of the fiber material is preferably 0.1 to 5 mass%. The amount of surface treatment agent attached to the fiber material can be determined, for example, by measuring the weight of a thoroughly dried fiber material, heat-treating it at 625°C, and then reweighing the fiber material, and dividing the weight loss of the fiber material due to the heat treatment by the weight of the fiber material before the heat treatment.

[0048] The fibrous material is contained in an amount of 5% by mass or more and 80% by mass or less, preferably 10% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 60% by mass or less of the polyarylene sulfide resin composition.

[0049] The filler is not particularly limited, but may be metal materials such as nickel, copper, gold, silver, aluminum, zinc, tin, lead, chromium, platinum, palladium, tungsten, molybdenum, alloys or blends thereof; or carbon materials such as artificial graphite, natural graphite, glassy carbon, carbon black, acetylene black, ketjen black, and carbon nanotubes, or a mixture of any one or more of these. The filler may be surface-treated with a compound containing a silanol group to enhance its compatibility with the polyarylene sulfide.

[0050] The filler is contained in an amount of 10% by mass or less, preferably 5% by mass or less, of the polyarylene sulfide resin composition. When contained within the above range, the mechanical strength of the polyarylene sulfide resin composition can be improved without reducing moldability.

[0051] The impact resistance additive is not particularly limited, but examples thereof include thermoplastic elastomers obtained by copolymerizing α-olefins with vinyl polymerizable compounds, and one or a mixture of two or more types can be used. Examples of α-olefins include α-olefins having 2 to 8 carbon atoms, such as ethylene, propylene, and 1-butene. Examples of vinyl polymerizable compounds include α,β-unsaturated carboxylic acids and alkyl esters thereof, such as (meth)acrylic acid and (meth)acrylic acid esters; α,β-unsaturated dicarboxylic acids and derivatives thereof, such as maleic acid, fumaric acid, and itaconic acid; and glycidyl (meth)acrylate.

[0052] The impact resistance modifier is contained in an amount of 20% by mass or less, preferably 5 to 10% by mass or less, of the polyarylene sulfide resin composition. When contained within the above range, the polyarylene sulfide resin composition can exhibit excellent impact resistance and tensile strength as well as excellent moldability and releasability.

[0053] The reinforcing agent is not particularly limited, but silica, alumina, glass beads, boron nitride, talc, silicates, silicon chloride, silicon carbide, metal oxides, carbonates, sulfates, etc. can be used, and any one or a mixture of two or more of these can be used.

[0054] The reinforcing agent is contained in an amount of 10% by mass or less, preferably 1 to 7% by mass or less, of the polyarylene sulfide resin composition. When contained within the above range, the strength, rigidity, heat resistance, dimensional stability, etc. of the polyarylene sulfide resin composition can be improved.

[0055] The antioxidant is not particularly limited, but for example, hindered phenol-based antioxidants, hindered amine-based antioxidants, sulfur-containing antioxidants, and phosphorus-containing antioxidants can be used, with hindered phenol-based antioxidants being particularly preferred.

[0056] The antioxidant is contained in an amount of 10% by mass or less, preferably 5% by mass or less, of the polyarylene sulfide resin composition.

[0057] (Preparation method) The method for preparing the polyarylene sulfide resin composition of the present invention is not particularly limited, but it can be prepared by, for example, feeding a mixture of raw materials into a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll, heating to a temperature of 280 to 380°C, and kneading the mixture, or by mixing the mixture with various mixers such as a dissolver or homogenizer. The order in which the raw materials are mixed is also not particularly limited, and any of the following methods may be used: blending all the raw materials and then melt-kneading them using the above-mentioned method; blending some of the raw materials and then melt-kneading them using the above-mentioned method, and then blending the remaining raw materials and melt-kneading them; blending some of the raw materials and then melt-kneading them using a single-screw or twin-screw extruder, while mixing the remaining raw materials using a side feeder. Small amounts of additive components can also be added to the mixture after other components have been kneaded and pelletized using the above-mentioned method, before molding.

[0058] The present invention also relates to a method for improving the processability of a polyarylene sulfide resin, which comprises adding a zinc dialkyldithiophosphate to the polyarylene sulfide resin.

[0059] In the method of the present invention, by adding zinc dialkyldithiophosphate to a polyarylene sulfide resin composition, moldability can be improved. Furthermore, the mechanical properties and heat resistance, which usually decrease with improvement in moldability, are not reduced. In fact, by adding zinc dialkyldithiophosphate, the mechanical properties and heat resistance can be improved.

[0060] The polyarylene sulfide resin composition of the present invention can be formed into a molded article by a known molding method such as, but not limited to, injection molding, extrusion molding, compression molding, blow molding, injection compression molding, and transfer molding, and can be used for various applications. [Example]

[0061] The present invention will be described in more detail below using examples and comparative examples, but the scope of the present invention is not limited to the examples.

[0062] [Preparation of Polyarylene Sulfide Resin Composition] (Example) 59.3 parts by weight of polyphenylene sulfide (manufactured by NHU, trade name: 1150, linear type) was blended with 0.2 parts by weight of antioxidant (manufactured by BASF, trade name: Irganox 1098), 0.3 parts by weight of coupling agent (manufactured by Momentive, trade name: A-187), and 0.2 parts by weight of zinc dialkyldithiophosphate (manufactured by ADEKA, trade name: Z-112) and thoroughly mixed. Then, 40 parts by weight of glass fiber (manufactured by Nitto Boseki Co., Ltd., trade name: CS3J-256, average fiber diameter 10 μm, average fiber length 3 mm, aminosilane treatment) was added, and the mixture was melt-kneaded at 310 °C using a twin-screw extruder to prepare a polyarylene sulfide resin composition. The resulting strand was cut using a pelletizer to obtain pellets.

[0063] (Comparative Example 1) Polyarylene sulfide resin pellets were obtained in the same manner as in the above Examples, except that 59.5 parts by mass of polyphenylene sulfide was blended instead of adding zinc dialkyldithiophosphate.

[0064] (Comparative Example 2) Polyarylene sulfide resin pellets were obtained in the same manner as in the above examples, except that 0.2 parts by mass of a long-chain fatty acid ester (manufactured by Clariant, trade name: LICOWAX OP) was blended instead of adding zinc dialkyldithiophosphate.

[0065] The formulations of the polyarylene sulfide resin compositions prepared in Examples and Comparative Examples 1 and 2 are shown in Table 1 below.

[0066] [Table 1]

[0067] [evaluation] The obtained pellets of the Example and Comparative Examples 1 and 2 were used to evaluate the following properties.

[0068] (Charpy impact strength) The pellets obtained in Examples and Comparative Examples 1 and 2 were injection molded using an injection molding machine to prepare impact strength test pieces in accordance with ISO 180. Using the impact strength test pieces thus obtained, Charpy impact strength (kJ / m) was measured at 23°C in accordance with ISO 180. 2 ) was measured.

[0069] (Tensile strength and elongation at break) The obtained pellets of Examples and Comparative Examples 1 and 2 were injection molded using an injection molding machine to prepare tensile test specimens in accordance with ISO 527. Using the tensile test specimens thus obtained, the tensile strength (MPa) and elongation at break (%) were measured in accordance with ISO 527 at a test speed of 5 mm / min.

[0070] (Flexural strength and flexural modulus) The obtained pellets of the Examples and Comparative Examples 1 and 2 were injection molded using an injection molding machine to prepare bending test specimens in accordance with ISO 178. Using the bending test specimens thus obtained, bending strength (MPa) and bending modulus (MPa) were measured in accordance with ISO 178 at a test speed of 2 mm / min.

[0071] (heat deflection temperature) The obtained pellets of Examples and Comparative Examples 1 and 2 were injection molded using an injection molding machine to prepare load-deflection test specimens in accordance with ISO 75. Using the test specimens for the load-deflection test thus obtained, the heat deflection temperature (load-deflection temperature) was measured flatwise at a load of 1.8 MPa in accordance with ISO 75.

[0072] (crystallization temperature) A small amount of sample was cut out from the dried pellets obtained in Examples and Comparative Examples 1 and 2, and the temperature was raised to 300°C at 20°C / min and maintained at that temperature for 10 minutes to completely melt the polyarylene sulfide resin crystals. Thereafter, the sample was cooled at 20°C / min, and the exothermic peak temperature of the crystallization was taken as the crystallization temperature.

[0073] (Moldability) The obtained pellets of the Example and Comparative Examples 1 and 2 were injection molded at a molding temperature of 310°C using an injection molding machine, and the injection pressure was measured.

[0074] (Surface appearance) The obtained pellets of the Example and Comparative Examples 1 and 2 were injection molded into ISO dumbbells for tensile testing using an injection molding machine at a molding temperature of 310°C, a mold temperature of 150°C, and a constant speed of 50 mm / sec, and the appearance of the dumbbells was compared visually.

[0075] The results of the above measurements are shown in Table 2 below.

[0076] [Table 2]

[0077] The results in Table 2 show that the polyarylene sulfide resins of the examples using zinc dialkyldithiophosphate not only exhibited excellent moldability with a significantly reduced injection pressure, but also improved mechanical properties such as Charpy impact strength, tensile strength, elongation at break, flexural strength, and flexural modulus. Furthermore, the heat deflection temperature was not lowered, and the surface appearance was also excellent.

[0078] On the other hand, Comparative Example 1, which did not contain zinc dialkyldithiophosphate, had poor moldability due to the high injection pressure. Also, Comparative Example 2, which contained a long-chain fatty acid ester instead of zinc dialkyldithiophosphate, had a lower injection pressure and improved moldability, but the Charpy impact strength, tensile strength, flexural strength, and flexural modulus all decreased, resulting in a significant deterioration in mechanical properties. [Industrial Applicability]

[0079] INDUSTRIAL APPLICABILITY The polyarylene sulfide resin composition of the present invention is not only excellent in moldability but also excellent in mechanical properties such as strength and impact resistance, as well as heat resistance, and therefore can be used in high-temperature environments and is therefore useful.

Claims

1. A moldability improver for polyarylene sulfide resins, comprising zinc dialkyldithiophosphate.

2. 2. The moldability improver for polyarylene sulfide resin according to claim 1, wherein the alkyl group of said zinc dialkyldithiophosphate has 5 to 20 carbon atoms.

3. The moldability improver for a polyarylene sulfide resin according to claim 1 or 2, wherein the polyarylene sulfide is polyphenylene sulfide.

4. A method for improving the moldability of a polyarylene sulfide resin, comprising adding a zinc dialkyldithiophosphate to the polyarylene sulfide resin.

5. 5. The method according to claim 4, wherein the alkyl group of the zinc dialkyldithiophosphate has 5 to 20 carbon atoms.

6. The method according to claim 4 or 5, wherein the zinc dialkyldithiophosphate is added in an amount of 0.001 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin.

7. 7. The method of claim 4, wherein the polyarylene sulfide is polyphenylene sulfide.

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