Polyphenylene sulfide resin composition and molded article made thereof

Abstract

The present invention addresses the problem of achieving: a polyphenylene sulfide resin composition which has flame retardancy, flexibility and toughness at the same time; and a molded article which is formed from this polyphenylene sulfide resin composition. The purpose of the present invention is to provide a polyphenylene sulfide resin composition which contains (a) a polyphenylene sulfide resin and (b) a silicone polymer compound, wherein: the content of the component (b) relative to 100 parts by weight of the component (a) is 3 to 40 parts by weight; with respect to the morphology (phase structure) of the polyphenylene sulfide resin composition, the polyphenylene sulfide resin composition has a phase separation structure wherein the component (a) forms a continuous phase and the component (b) forms dispersed phases that are dispersed with a number average dispersed particle diameter of 3.0 μm or less; a test piece which is obtained by injection molding the polyphenylene sulfide resin composition at a cylinder temperature of 310°C and a mold temperature of 145°C has a bending modulus of elasticity of 3.0 GPa or less as determined by a bending test that is performed in accordance with ISO 178; and the flame retardancy of a test piece that has a thickness 1.6 mm t or less is V-0 as determined according to UL 94 standard.

Description

[Technical Field]

[0001] The present invention relates to a polyphenylene sulfide resin composition and a molded article using the same. [Background technology]

[0002] Polyphenylene sulfide (hereinafter sometimes abbreviated as "PPS") resin is a super engineering plastic that has a good balance of properties such as heat resistance, chemical resistance, and flame retardancy. In addition, due to its cost advantage over other super engineering plastics, PPS resin is a highly versatile resin material second only to the five major engineering plastics, and is used in a wide range of applications such as automobiles, housing equipment, and electrical and electronic applications.

[0003] In recent years in particular, in response to social issues such as the SDGs, there has been a strong demand for energy conservation through weight reduction in automotive applications and for greenhouse gas emissions reduction through electrification. In response to these demands, PPS resin can achieve weight reduction by replacing metals and can demonstrate high insulation and heat resistance properties for electrification, so its use in automotive applications is on an increasing trend year by year.

[0004] On the other hand, an essential issue in expanding the applications of PPS resin is that, compared to other resins, it has low toughness, as represented by the tensile elongation at break in a tensile test, and is therefore brittle.

[0005] Therefore, for applications requiring toughness, a PPS resin composition containing an olefin-based elastomer has been developed and put into practical use, as described in Patent Document 1. By blending an olefin-based elastomer, which is a more flexible material than PPS resin, in this composition, improvements in both flexibility and toughness have been achieved.

[0006] Patent Document 2 discloses a heat-shrinkable tube made of a PPS resin composition that is imparted with flexibility by adding a thermoplastic elastomer and a plasticizer to the PPS resin.

[0007] Furthermore, Patent Documents 3 and 4 describe a method of softening PPS resin by adding a silicone elastomer to the resin. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 61-21156 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-6919 [Patent Document 3] Japanese Patent Application Publication No. 2017-222867 [Patent Document 4] Japanese Patent Application Publication No. 2017-214586 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when the present inventors evaluated the flame retardancy of a resin composition comprising PPS resin and an olefin-based elastomer, as described in Patent Document 1, they found that the flame retardancy of the resin composition was significantly lower than that of PPS resin alone. This is thought to be because, while PPS resin alone has high flame retardancy, the flame retardancy of the composition as a whole was reduced by blending an olefin-based elastomer, which has significantly lower flame retardancy. While this composition has the advantages of flexibility and toughness, it does not exhibit the excellent flame retardancy that PPS resin inherently possesses, which limits its application.

[0010] The heat-shrinkable tube made of the PPS resin composition described in Patent Document 2 also contains a low-molecular-weight compound plasticizer in addition to the thermoplastic elastomer in order to impart flexibility, but the addition of these compounds reduces flame retardancy, so it is not possible to obtain flame retardancy rating V-0 under the UL94 standard.

[0011] Furthermore, as described in the examples of Patent Document 3, the PPS resin composition described in Patent Document 3 is inferior in flexibility, has low tensile elongation at break, and does not have sufficient toughness, and a PPS resin composition that combines flame retardancy, flexibility, and toughness has not been realized.

[0012] The PPS resin composition described in Patent Document 4 has excellent flexibility and tensile elongation at break, as described in the examples of Patent Document 4, but it does not have excellent flame retardancy in addition to both properties.

[0013] Therefore, an object of the present invention is to obtain a polyphenylene sulfide resin composition that has flexibility and toughness while maintaining the flame retardancy of PPS resin. [Means for solving the problem]

[0014] As a result of investigations aimed at solving these problems, the present inventors have discovered that a polyphenylene sulfide resin composition containing (a) a polyphenylene sulfide resin (hereinafter sometimes referred to as "component (a)") and (b) a silicone-based polymer compound (hereinafter sometimes referred to as "component (b)") in a specific composition, in which component (b) is dispersed in a specific state, and which is substantially free of inorganic fillers such as glass fibers and has a flexural modulus of elasticity of a specific level or less, exhibits excellent flexibility, exhibits flame retardancy (UL94 standard V-0 (1.6 mmt or less)) in thin-walled molded articles, and also has the property of having toughness. That is, the present invention has been made to solve at least part of the above-mentioned problems. (1) A polyphenylene sulfide resin composition comprising (a) a polyphenylene sulfide resin and (b) a silicone polymer compound, component (b) is selected from the group consisting of silicone gum, silicone elastomer, silicone resin, and a composite containing organopolysiloxane;A polyphenylene sulfide resin composition, wherein the content of component (b) per 100 parts by weight of component (a) is 3 to 40 parts by weight, and the morphology (phase structure) of the polyphenylene sulfide resin composition has a phase-separated structure in which component (a) forms a continuous phase and component (b) forms a dispersed phase in which the component has a number average dispersed particle size of 3.0 μm or less, and wherein test pieces obtained by injection molding the polyphenylene sulfide resin composition at a cylinder temperature of 310°C and a mold temperature of 145°C have a flexural modulus of 3.0 GPa or less in a bending test according to ISO 178 (2010), and the flame retardancy measured on test pieces having a thickness of 1.6 mm or less in accordance with UL94 standards is V-0. (2) The polyphenylene sulfide resin composition according to (1), wherein (c) an olefin-based elastomer is blended in an amount of 1 part by weight or more and 40 parts by weight or less per 100 parts by weight of the component (a). (3) The polyphenylene sulfide resin composition according to (1) or (2), wherein the flame retardancy of the polyphenylene sulfide resin composition is V-0 when measured on a test piece having a thickness of 1.0 mm or less in accordance with the UL94 standard. (4) The polyphenylene sulfide resin composition according to any one of (1) to (3), wherein the polyphenylene sulfide resin composition has a tensile elongation at break of 10% or more in a tensile test according to ISO 527-1, 2 (2012). (5) The polyphenylene sulfide resin composition according to any one of (1) to (4), wherein the morphology (phase structure) of the polyphenylene sulfide resin composition has a phase-separated structure in which the component (a) forms a continuous phase and the component (b) forms a dispersed phase in which the component (b) is dispersed with a number average dispersed particle size of 1.0 μm or less. (6) The polyphenylene sulfide resin composition according to any one of (1) to (5), wherein the component (a) is a polyphenylene sulfide resin composition that is measured using a capillograph at 300°C under the conditions of orifice length L (mm) / orifice diameter D (mm) = 10 at a shear rate of 60 to 6080 s -1The polyphenylene sulfide resin composition has a non-Newtonian index N of 1.30 or more, calculated by measuring the shear stress at 100° C. and applying the shear rate-shear stress relationship to the following formula (1):

[0015] SR=K·SS N ···(1) (where N is the non-Newtonian exponent, SR is the shear rate (1 / sec), and SS is the shear stress (dyne / cm 2 ), where K is a constant. (7) The polyphenylene sulfide resin composition according to any one of (1) to (6), wherein the polyphenylene sulfide resin composition has a shear rate of 122 s when measured using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10. -1 A polyphenylene sulfide resin composition having a melt viscosity of 400 Pa·s or more. (8) The polyphenylene sulfide resin composition according to any one of (1) to (7), wherein the component (b) is a silicone-based core-shell rubber. (9) A molded article made of the polyphenylene sulfide resin composition according to any one of (1) to (8). (10) A molded article for piping, which is made of the polyphenylene sulfide resin composition according to (9) and has a hollow shape. [Effects of the Invention]

[0016] According to the present invention, it is possible to obtain a polyphenylene sulfide resin composition having excellent flame retardancy, flexibility, and toughness, and a molded article made of the same. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail.

[0018] (1) (a) Polyphenylene sulfide resin (component (a)) The polyphenylene sulfide resin (a) used in the present invention is a polymer having a repeating unit represented by the following structural formula:

[0019] [ka]

[0020] From the viewpoint of heat resistance, a polymer containing 70 mol % or more, and even more preferably 90 mol % or more, of a polymer containing a repeating unit represented by the above structural formula is preferred. Furthermore, the PPS resin constituting component (a) may be composed of repeating units having the following structure, etc., in an amount of less than 30 mol % of the repeating units.

[0021] [ka]

[0022] A PPS copolymer partially having such a structure has a melting point lower than the general melting point of PPS, 280° C., and therefore such a resin composition is advantageous in terms of moldability.

[0023] Although there are no particular limitations on the number average molecular weight of the PPS resin used in the present invention, in order to obtain better mechanical properties, the number average molecular weight is preferably 10,000 to 60,000, more preferably 12,000 to 50,000, even more preferably 14,000 to 40,000, and even more preferably 16,000 to 35,000. If the number average molecular weight is small, the mechanical properties of the PPS resin itself will deteriorate, so the number average molecular weight is preferably 10,000 or more. On the other hand, if the number average molecular weight exceeds 60,000, the melt viscosity will increase significantly, which tends to be undesirable for molding processing.

[0024] The weight-average molecular weight of the PPS resin constituting component (a) used in the present invention is preferably 40,000 to 100,000, more preferably 50,000 to 95,000, and even more preferably 70,000 to 90,000. If the weight-average molecular weight is too small, the melt viscosity of the PPS resin composition is likely to be insufficient, resulting in insufficient kneading strength during melt kneading. This tends to increase the number-average dispersed particle size of the silicone polymer compound (b) in the PPS resin composition, resulting in reduced toughness and flame retardancy of the PPS resin composition. Therefore, a weight-average molecular weight of 40,000 or greater is preferred. On the other hand, if the weight-average molecular weight exceeds 100,000, the melt viscosity will be excessive, which tends to be undesirable for molding and processing. The number-average dispersed particle size is determined by the method described in the Examples section.

[0025] The number average molecular weight and weight average molecular weight of the component (a) in the present invention are values ​​calculated in terms of polystyrene using a gel permeation chromatography (GPC) manufactured by Senshu Scientific.

[0026] The non-Newtonian index N of the PPS resin constituting component (a) used in the present invention is preferably 1.30 or greater, more preferably 1.35 or greater, even more preferably 1.40 or greater, and particularly preferably 1.50 or greater. A non-Newtonian index of less than 1.30 tends to be undesirable due to the relatively low viscosity of the PPS resin in a low-shear flow field, resulting in poor molding processability and reduced flame retardancy due to dripping during flame retardancy testing and surface renewal. While there is no upper limit for the non-Newtonian index, a non-Newtonian index of more than 5 tends to significantly increase the melt viscosity due to the formation of highly branched and crosslinked structures, which is undesirable for molding processability. Methods for obtaining a PPS resin with a non-Newtonian index of 1.30 or greater include using a polyhalogenated aromatic compound having three or more halogen atoms per molecule as a polymerization raw material to introduce a branched structure into the polymer, and performing thermal oxidative crosslinking by heating the PPS resin in an oxygen atmosphere after polymerization or by adding a crosslinking agent such as a peroxide.

[0027] The non-Newtonian index in the present invention is measured using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10, and a shear rate of 60 to 6080 s -1 The shear stress at the shear rate is measured, and the shear stress is calculated by applying the relationship between shear rate and shear stress to the following formula (1).

[0028] SR=K·SS N ···(1) (where N is the non-Newtonian exponent, SR is the shear rate (1 / sec), and SS is the shear stress (dyne / cm 2 ), where K is a constant. The melt viscosity of the PPS resin constituting component (a) used in the present invention is preferably 50 to 3000 Pa·s, more preferably 150 to 2500 Pa·s, even more preferably 300 to 2000 Pa·s, and particularly preferably 500 to 1500 Pa·s. 800 to 1200 Pa·s is even more preferable. If the melt viscosity of the PPS resin is low, the melt viscosity of the PPS resin composition will not be sufficiently high, resulting in insufficient kneading strength during melt kneading. This tends to increase the number-average dispersed particle size of the silicone polymer compound (b) in the PPS resin composition, resulting in reduced toughness and flame retardancy of the PPS resin composition. Therefore, the melt viscosity of the PPS resin is preferably 50 Pa·s or higher. On the other hand, if the melt viscosity of the PPS resin exceeds 3000 Pa·s, the excessive melt viscosity tends to be undesirable for molding and processing.

[0029] The melt viscosity of the PPS resin in the present invention was measured using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10, at a shear rate of 122 s -1 is the value at

[0030] A method for producing the PPS resin constituting component (a) used in the present invention will be described below, but the method is not limited to the following method as long as a PPS resin having the above-mentioned properties can be obtained.

[0031] First, the polyhalogenated aromatic compound, sulfidizing agent, polymerization solvent, molecular weight regulator, polymerization aid and polymerization stabilizer used in the production method will be described.

[0032] [Polyhalogenated aromatic compounds] The polyhalogenated aromatic compound refers to a compound having two or more halogen atoms in one molecule. Specific examples include polyhalogenated aromatic compounds such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, and 1-methoxy-2,5-dichlorobenzene, and preferably p-dichlorobenzene. In addition, for the purpose of introducing carboxyl groups, one preferred embodiment is to use a carboxyl group-containing dihalogenated aromatic compound such as 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 2,6-dichlorobenzoic acid, or 3,5-dichlorobenzoic acid, or a mixture thereof, as a copolymerization monomer. Although it is also possible to combine two or more different polyhalogenated aromatic compounds to form a copolymer, it is preferable to use a p-dihalogenated aromatic compound as the main component.

[0033] The amount of polyhalogenated aromatic compound used is, for example, in the range of 0.9 to 2.0 moles, preferably 0.95 to 1.5 moles, and more preferably 1.005 to 1.2 moles per mole of sulfidizing agent, in order to obtain a PPS resin with a viscosity suitable for processing.

[0034] [Sulfidizing agent] The sulfidizing agent includes alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

[0035] Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these, with sodium sulfide being preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrous forms.

[0036] Specific examples of alkali metal hydrosulfides include sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these, with sodium hydrosulfide being preferred. These alkali metal hydrosulfides can be used as hydrates, aqueous mixtures, or anhydrous forms.

[0037] Alternatively, an alkali metal sulfide prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can be used.Also, an alkali metal sulfide can be prepared from an alkali metal hydrosulfide and an alkali metal hydroxide and then transferred to a polymerization vessel for use.

[0038] Alternatively, an alkali metal sulfide prepared in situ in the reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can be used.Also, an alkali metal sulfide can be prepared from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide, and then transferred to a polymerization vessel for use.

[0039] When a part of the sulfidizing agent is lost before the start of the polymerization reaction due to a dehydration operation or the like, the amount of the charged sulfidizing agent means the remaining amount obtained by subtracting the lost amount from the actual charged amount.

[0040] It is also possible to use an alkali metal hydroxide and / or alkaline earth metal hydroxide together with the sulfidizing agent. Specific examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and mixtures of two or more of these. Specific examples of alkaline earth metal hydroxides include calcium hydroxide, strontium hydroxide, barium hydroxide, etc., and sodium hydroxide is preferably used among them.

[0041] When an alkali metal hydrosulfide is used as the sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide simultaneously. The amount used is, for example, in the range of 0.95 to 1.20 mol, preferably 1.00 to 1.15 mol, and more preferably 1.005 to 1.100 mol per mol of the alkali metal hydrosulfide.

[0042] [Polymerization solvent] As the polymerization solvent, an organic polar solvent is preferably used. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-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, hexamethylphosphoric triamide, dimethyl sulfone, and tetramethylene sulfoxide, and mixtures thereof. These solvents are preferably used because of their high reaction stability. Among these, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as "NMP") is particularly preferably used.

[0043] The amount of the organic polar solvent used is selected from the range of 2.0 to 10 moles, preferably 2.25 to 6.0 moles, more preferably 2.5 to 5.5 moles per mole of the sulfidizing agent.

[0044] [Molecular weight regulator] A monohalogen compound (which does not necessarily have to be an aromatic compound) can be used in combination with the polyhalogenated aromatic compound in order to form terminals in the resulting PPS resin or to adjust the polymerization reaction or molecular weight.

[0045] [Polymerization aid] In one preferred embodiment, a polymerization aid is used to obtain a PPS resin with a relatively high degree of polymerization in a shorter time. Here, the polymerization aid refers to a substance that has the effect of increasing the viscosity of the resulting PPS resin (a). Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. These can be used alone or in combination of two or more. Among these, organic carboxylates, water, and alkali metal chlorides are preferred, with alkali metal carboxylates being preferred as the organic carboxylates and lithium chloride being preferred as the alkali metal chlorides.

[0046] The alkali metal carboxylate is represented by the general formula R(COOM) n (wherein R is an n-valent aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group which may be substituted with an aliphatic hydrocarbon group, or an aromatic hydrocarbon group which may be substituted with an aliphatic hydrocarbon group; M is an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium; and n is an integer of 1 to 3.) The alkali metal carboxylate can also be used as a hydrate, an anhydride, or an aqueous solution. Specific examples of the alkali metal carboxylate include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof.

[0047] The alkali metal carboxylate may be formed by adding and reacting an organic acid with one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates in approximately equal chemical equivalents. Among the alkali metal carboxylates, lithium salts are highly soluble in the reaction system and have a significant auxiliary effect, but are expensive, while potassium, rubidium, and cesium salts are thought to have insufficient solubility in the reaction system. Therefore, sodium acetate, which is inexpensive and has moderate solubility in the polymerization system, is most preferably used.

[0048] When these alkali metal carboxylates are used as polymerization aids, the amount used is usually in the range of 0.01 mol to 2 mol per mol of the charged alkali metal sulfide, and in terms of obtaining a higher degree of polymerization, the amount used is preferably in the range of 0.1 mol to 0.6 mol, and more preferably in the range of 0.2 mol to 0.5 mol.

[0049] When water is used as a polymerization aid, the amount added is usually in the range of 0.3 mol to 15 mol per mol of the charged alkali metal sulfide, and in order to obtain a higher degree of polymerization, the amount is preferably in the range of 0.6 mol to 10 mol, and more preferably in the range of 1 mol to 5 mol.

[0050] Of course, two or more of these polymerization aids can be used in combination. For example, when an alkali metal carboxylate and water are used in combination, a higher molecular weight can be achieved with a smaller amount of each.

[0051] The timing of addition of these polymerization aids is not particularly specified, and they may be added at any time during the pre-step, at the start of polymerization, or during the polymerization, as described below, or may be added in several divided portions, but when an alkali metal carboxylate is used as the polymerization aid, it is more preferable to add it simultaneously at the start of the pre-step or at the start of polymerization from the viewpoint of ease of addition. Also, when water is used as the polymerization aid, it is effective to add it during the polymerization reaction after charging the polyhalogenated aromatic compound.

[0052] [Polymerization stabilizer] Polymerization stabilizers can be used to stabilize the polymerization reaction system and prevent side reactions. Polymerization stabilizers contribute to stabilizing the polymerization reaction system and suppress undesirable side reactions. One indicator of side reactions is the production of thiophenol, and the addition of a polymerization stabilizer can suppress this production. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The aforementioned alkali metal carboxylates also function as polymerization stabilizers. Furthermore, when using an alkali metal hydrosulfide as a sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide simultaneously. However, an excess amount of alkali metal hydroxide relative to the sulfidizing agent can also function as a polymerization stabilizer.

[0053] These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is preferably used in a proportion of usually 0.02 to 0.2 mol, preferably 0.03 to 0.1 mol, more preferably 0.04 to 0.09 mol per mol of the charged alkali metal sulfide. If this proportion is too small, the stabilizing effect is insufficient, while if it is too large, it tends to be economically disadvantageous and the polymer yield tends to decrease.

[0054] The timing of adding the polymerization stabilizer is not particularly specified, and it may be added at any time during the pre-step described below, at the start of polymerization, or during polymerization, or may be added in multiple divided portions, but it is more preferable to add it simultaneously at the start of the pre-step or at the start of polymerization from the viewpoint of ease.

[0055] Next, a preferred method for producing the PPS resin used in the present invention will be specifically explained in order, including a pre-process, a polymerization reaction process, a recovery process, and a post-treatment process, but the present invention is not limited to this method.

[0056] [Pre-process] In the production method for PPS resin, the sulfidizing agent is usually used in the form of a hydrate, and it is preferable to heat the mixture containing the organic polar solvent and the sulfidizing agent and remove excess water from the system before adding the polyhalogenated aromatic compound.

[0057] As mentioned above, sulfidizing agents prepared in situ in the reaction system or in a separate vessel from the polymerization vessel can also be used. While there are no particular limitations on this method, a preferred method involves adding an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent under an inert gas atmosphere at room temperature to 150°C, preferably room temperature to 100°C, and then heating the mixture to at least 150°C or higher, preferably 180 to 260°C, under atmospheric or reduced pressure, to distill off water. A polymerization aid may also be added at this stage. To promote the distillation of water, the reaction may be carried out with the addition of toluene or the like.

[0058] In the polymerization reaction, the amount of water in the polymerization system is preferably 0.3 to 10.0 moles per mole of the charged sulfidizing agent. Here, the amount of water in the polymerization system is the amount of water charged to the polymerization system minus the amount of water removed from the polymerization system. The charged water may be in any form, such as water, an aqueous solution, or water of crystallization.

[0059] [Polymerization reaction process] PPS resin is produced by reacting a sulfidizing agent with a polyhalogenated aromatic compound in an organic polar solvent at a temperature ranging from 200°C to less than 290°C.

[0060] When starting the polymerization reaction process, the organic polar solvent, sulfidizing agent, and polyhalogenated aromatic compound are mixed together, preferably in an inert gas atmosphere, at a temperature ranging from room temperature to 240°C, and preferably from 100°C to 230°C. A polymerization aid may be added at this stage. These raw materials may be added in any order, or simultaneously.

[0061] The mixture is usually heated to a temperature in the range of 200° C. to less than 290° C. There are no particular restrictions on the temperature-raising rate, but a rate of 0.01 to 5° C. / min is usually selected, and a range of 0.1 to 3° C. / min is more preferred.

[0062] In general, the temperature is finally raised to a temperature of 250 to less than 290° C., and the reaction is carried out at that temperature for usually 0.25 to 50 hours, preferably 0.5 to 20 hours.

[0063] A method of reacting at 200° C. to 260° C. for a certain period of time before reaching the final temperature, and then raising the temperature to 270° C. to less than 290° C., is effective in obtaining a higher degree of polymerization. In this case, the reaction time at 200° C. to 260° C. is usually selected from the range of 0.25 to 20 hours, and preferably from the range of 0.25 to 10 hours.

[0064] In order to obtain a polymer with a higher degree of polymerization, it may be effective to carry out the polymerization in multiple stages. When carrying out the polymerization in multiple stages, it is effective to carry out the polymerization when the conversion rate of the polyhalogenated aromatic compound in the system at 245°C reaches 40 mol% or more, preferably 60 mol%.

[0065] The conversion rate of polyhalogenated aromatic compounds (abbreviated as "PHA" herein) is a value calculated using the following formula: The amount of remaining PHA can usually be determined by gas chromatography.

[0066] (A) When polyhalogenated aromatic compounds are added in excess of alkali metal sulfides in terms of molar ratio Conversion rate = [amount of PHA charged (mol) - amount of remaining PHA (mol)] / [amount of PHA charged (mol) - amount of excess PHA (mol)].

[0067] (B) Cases other than (A) above Conversion rate = [amount of PHA charged (mol) - amount of remaining PHA (mol)] / [amount of PHA charged (mol)].

[0068] [Recovery process] In the method for producing PPS resin, after polymerization is complete, solid matter is recovered from the polymerization reaction product containing the polymer, solvent, etc. As a recovery method, it is essential to employ a method in which the polymer is slowly cooled after the polymerization reaction is complete and the particulate polymer is recovered. There are no particular restrictions on the cooling rate, but it is typically about 0.1°C / min to 3°C / min. It is not necessary to cool at the same rate throughout the entire cooling process; it is also possible to employ a method in which the polymer particles are cooled at a rate of 0.1 to 1°C / min until they crystallize and precipitate, and then slowly cooled at a rate of 1°C / min or faster.

[0069] [Post-processing process] The PPS resin may be produced through the above-mentioned polymerization and recovery steps, and then subjected to acid treatment, hot water treatment, washing with an organic solvent, or alkali metal or alkaline earth metal treatment.

[0070] The acid treatment is carried out as follows: There are no particular restrictions on the acid used in the acid treatment of the PPS resin, so long as it does not have the effect of decomposing the PPS resin, and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Of these, acetic acid and hydrochloric acid are more preferably used, but acids such as nitric acid, which decompose and deteriorate the PPS resin, are not preferred.

[0071] The acid treatment can be carried out by immersing the PPS resin in an acid or an aqueous solution of an acid, with stirring or heating as necessary. For example, when using acetic acid, a sufficient effect can be obtained by immersing the PPS resin powder in an aqueous solution of pH 4 heated to 80 to 200°C and stirring for 30 minutes. The pH after treatment may be 4 or higher, for example, about pH 4 to 8. The acid-treated PPS resin is preferably washed several times with water or warm water to remove residual acid or salt. The water used for washing is preferably distilled water or deionized water, so as not to impair the desired chemical modification effect of the PPS resin by the acid treatment.

[0072] The hot water treatment is carried out as follows: When treating the PPS resin with hot water, the temperature of the hot water is preferably 100° C. or higher, more preferably 120° C. or higher, even more preferably 150° C. or higher, and particularly preferably 170° C. or higher. Temperatures below 100° C. are not preferred because the desired chemical modification effect of the PPS resin is small.

[0073] To achieve the desired chemical modification effect of the PPS resin by hot water washing, it is preferable to use distilled or deionized water. There are no particular restrictions on the hot water treatment procedure; it can be carried out by adding a specified amount of PPS resin to a specified amount of water, heating and stirring in a pressure vessel, or by continuous hot water treatment. The ratio of PPS resin to water is preferably higher, but a bath ratio of 200 g or less of PPS resin to 1 liter of water is usually selected.

[0074] Furthermore, since decomposition of the terminal groups is undesirable, it is desirable to carry out the treatment in an inert atmosphere to avoid this.Furthermore, after this hot water treatment, the PPS resin is preferably washed several times with warm water to remove any remaining components.

[0075] When washing with an organic solvent, the procedure is as follows. There are no particular restrictions on the organic solvents used to wash PPS resin, as long as they do not have the effect of decomposing PPS resin. Examples include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphoramide, and piperazinones; sulfoxide and sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; ether solvents such as dimethyl ether, dipropyl ether, dioxane, and tetrahydrofuran; halogenated solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene; alcohol and phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol; and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, it is particularly preferable to use N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform, etc. These organic solvents may be used alone or in combination of two or more.

[0076] Washing with an organic solvent can be performed by immersing the PPS resin in the organic solvent, with stirring or heating as necessary. There are no particular restrictions on the washing temperature when washing PPS resin with an organic solvent; any temperature between room temperature and approximately 300°C can be selected. While higher washing temperatures tend to improve cleaning efficiency, a washing temperature between room temperature and 150°C is usually sufficient. Washing can also be performed under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There are also no particular restrictions on the washing time. While this depends on the washing conditions, in the case of batch washing, washing for 5 minutes or more usually produces sufficient results. Continuous washing is also possible.

[0077] Examples of methods for alkali metal or alkaline earth metal treatment include adding an alkali metal salt or alkaline earth metal salt before, during, or after the pre-processing step; adding an alkali metal salt or alkaline earth metal salt to the polymerization reactor before, during, or after the polymerization step; or adding an alkali metal salt or alkaline earth metal salt at the beginning, middle, or end of the washing step. Among these, the easiest method is adding an alkali metal salt or alkaline earth metal salt after removing residual oligomers and salts by washing with an organic solvent or warm or hot water. The alkali metal or alkaline earth metal is preferably introduced into the PPS in the form of an alkali metal ion or alkaline earth metal ion, such as an acetate, hydroxide, or carbonate. Excess alkali metal salt or alkaline earth metal salt is preferably removed by washing with warm water or the like. The concentration of the alkali metal ion or alkaline earth metal ion when introducing the alkali metal or alkaline earth metal is preferably 0.001 mmol or more per gram of PPS, and more preferably 0.01 mmol or more. The temperature is preferably 50°C or higher, more preferably 75°C or higher, and particularly preferably 90°C or higher. There is no particular upper limit to the temperature, but from the viewpoint of operability, a temperature of 280°C or lower is usually preferred. The bath ratio (weight of cleaning solution relative to the weight of dry PPS) is preferably 0.5 or higher, more preferably 3 or higher, and even more preferably 5 or higher.

[0078] In the present invention, from the viewpoint of obtaining a polyphenylene sulfide resin composition excellent in retention stability, a method is preferred in which residual oligomers and residual salts are removed by repeating washing with an organic solvent and washing with warm water at about 80°C or the above-mentioned hot water several times, and then the resulting mixture is treated with an acid or an alkali metal salt or an alkaline earth metal salt, and particularly a method in which the mixture is treated with an alkali metal salt or an alkaline earth metal salt is more preferred.

[0079] Alternatively, the PPS resin can be used after being polymerized by a thermal oxidation crosslinking treatment, which involves heating in an oxygen atmosphere after polymerization or by heating with a crosslinking agent such as peroxide added.

[0080] When dry heat treatment is performed for the purpose of increasing the molecular weight by thermal oxidative crosslinking, the temperature is preferably 160 to 260°C, more preferably 170 to 250°C. The oxygen concentration is desirably 5% by volume or more, and even more desirably 8% by volume or more. There is no particular upper limit to the oxygen concentration, but it is limited to about 50% by volume. The treatment time is preferably 0.5 to 100 hours, more preferably 1 to 50 hours, and even more preferably 2 to 25 hours. The heat treatment device may be a conventional hot air dryer, or a rotary or stirring blade-equipped heating device; however, for efficient and more uniform treatment, it is more preferable to use a rotary or stirring blade-equipped heating device.

[0081] Dry heat treatment can also be performed to suppress thermal oxidative crosslinking and remove volatiles. The temperature is preferably 130 to 250°C, more preferably 160 to 250°C. In this case, the oxygen concentration is preferably less than 5% by volume, and even more preferably less than 2% by volume. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and even more preferably 1 to 10 hours. The heat treatment device may be a conventional hot air dryer, or a rotary or stirring blade-equipped heating device; however, for efficient and more uniform treatment, it is more preferable to use a rotary or stirring blade-equipped heating device.

[0082] The PPS resin constituting component (a) used in the present invention may have functional groups such as carboxyl groups or amino groups introduced into the terminals or side chains of the PPS resin to improve reactivity with the olefin-based elastomer (c) and other additives. A preferred embodiment has a functional group amount of 25 to 400 μmol / g, with 25 to 250 μmol / g being more preferred, 30 to 150 μmol / g being even more preferred, and 30 to 80 μmol / g being even more preferred. A functional group amount of 25 μmol / g or more is preferred because it ensures reactivity with the olefin-based elastomer (c) and other additives. On the other hand, a functional group amount of 400 μmol / g or less of the PPS resin is preferred because it can suppress deterioration in processability and flame retardancy and chemical resistance that accompany an increase in the amount of volatile components.

[0083] Examples of methods for introducing functional groups such as carboxyl groups and amino groups into PPS resin include copolymerizing a polyhalogenated aromatic compound containing carboxyl groups or amino groups with a sulfidizing agent, and adding a compound containing carboxyl groups or amino groups, such as maleic anhydride or sorbic acid, and reacting it with the PPS resin while melt-kneading. The type of functional group is preferably a carboxyl group or an amino group.

[0084] In the present invention, a plurality of PPS resins having different melt viscosities, non-Newtonian indices, or amounts of functional groups may be mixed and used.

[0085] (2)(c) Olefin-based elastomer Adding (c) an olefin-based elastomer to the polyphenylene sulfide resin composition of the present invention is preferable from the viewpoint of obtaining excellent flexibility and toughness of the resin composition. Furthermore, the effect of improving the melt viscosity of the resin composition improves the dispersibility of (b) the silicone-based polymer compound, thereby improving toughness and flame retardancy. Furthermore, an olefin-based elastomer is selected from the viewpoint of cost advantage over other flexible materials.

[0086] Examples of such (c) olefin-based elastomers include ethylene-butene copolymers, ethylene-propylene copolymers, ethylene-hexene copolymers, ethylene-octene copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-glycidyl methacrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-styrene copolymers, ethylene-methyl acrylate-glycidyl methacrylate copolymers, ethylene-ethyl acrylate-glycidyl methacrylate copolymers, and ethylene-vinyl acetate-glycidyl methacrylate copolymers. Among these, from the viewpoint of compatibility and dispersibility in PPS resins, ethylene-butene copolymers, ethylene-propylene copolymers, ethylene-glycidyl methacrylate copolymers, ethylene-methyl acrylate-glycidyl methacrylate copolymers, ethylene-ethyl acrylate-glycidyl methacrylate copolymers, and ethylene-vinyl acetate-glycidyl methacrylate copolymers are preferred. In particular, olefin elastomers containing a glycidyl group are preferred, and among these, ethylene-glycidyl methacrylate copolymers and ethylene-methyl acrylate-glycidyl methacrylate copolymers are preferred.

[0087] In a preferred embodiment, the olefin elastomer (c) used in the present invention contains a reactive functional group from the viewpoint of forming an intermolecular bond with the PPS resin.

[0088] (c) The reactive functional group possessed by the olefin-based elastomer is not particularly limited, and specific examples thereof include a vinyl group, an epoxy group, a carboxyl group, an acid anhydride group, an ester group, an aldehyde group, a carbonyldioxy group, a haloformyl group, an alkoxycarbonyl group, an amino group, a hydroxyl group, a styryl group, a methacryl group, an acrylic group, a ureido group, a mercapto group, a sulfide group, an isocyanate group, a hydrolyzable silyl group, and an oxazoline group. Among these, a hydroxyl group, an epoxy group, a carboxyl group, an amino group, an acid anhydride group, an amino group, a hydroxyl group, an isocyanate group, and an oxazoline group are preferred, and two or more of these reactive functional groups may be contained.

[0089] (c) Examples of methods for introducing a reactive functional group into an olefinic elastomer include blending a compound or resin compatible with the olefinic elastomer and containing the functional group, copolymerizing a polymerizable monomer containing the functional group or a functional group convertible to the functional group into the main chain, side chain, or terminal when polymerizing the olefinic elastomer, using an initiator containing the functional group or a functional group convertible to the functional group when polymerizing the olefinic elastomer, reacting an olefinic elastomer with a polymerizable monomer containing the functional group or a functional group convertible to the functional group in the presence of a radical generator, and modifying an olefinic elastomer by oxidation, thermal decomposition, etc. Among these, the methods of copolymerizing a polymerizable monomer containing the functional group or a functional group convertible to the functional group into the main chain, side chain, or terminal when polymerizing the olefinic elastomer and reacting an olefinic elastomer with a polymerizable monomer containing the functional group or a functional group convertible to the functional group in the presence of a radical generator are preferred from the standpoints of quality, cost, and control of the amount introduced.

[0090] The polymerizable monomer containing the functional group is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, crotonic acid, himic acid, acid anhydrides thereof, glycidyl acrylate, glycidyl methacrylate, glycidyl ethylacrylate, glycidyl itaconate, vinyl acetate, vinyl propionate, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0091] The amount of functional groups contained in (c) the olefinic elastomer is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1% by weight or more, based on the weight of the olefinic elastomer, from the viewpoint of ensuring sufficient reaction with (a) the PPS resin. As the reactivity with the PPS resin improves, compatibility improves, and fine dispersion of the olefinic elastomer in the PPS resin, along with improvements in impact properties and toughness, can be expected. The upper limit of the amount of functional groups is not particularly limited as long as the inherent properties of the olefinic elastomer are not impaired. Taking into consideration factors such as deterioration of fluidity, a range of 40% by weight or less is preferred, with 30% by weight or less being a more preferred example.

[0092] In an embodiment of the present invention, the blending amount of (c) olefin-based elastomer is preferably 1 to 40 parts by weight, more preferably 3 to 35 parts by weight, more preferably 5 to 30 parts by weight, even more preferably 5 to 25 parts by weight, and particularly preferably 5 to 15 parts by weight, per 100 parts by weight of the PPS resin constituting component (a). If the amount of olefin-based elastomer exceeds 40 parts by weight per 100 parts by weight of PPS resin, the toughness tends to decrease due to coarsening of the olefin-based elastomer in the PPS resin. Flame retardancy also tends to decrease. On the other hand, if the amount of olefin-based elastomer is less than 1 part by weight per 100 parts by weight of PPS resin, the effect of improving the flexibility and toughness of the resin composition is small, which is undesirable.

[0093] In addition, it is also preferable to use two or more types of olefin-based elastomers in combination from the viewpoint of improving dispersibility.

[0094] When (c) an olefinic elastomer is blended into the polyphenylene sulfide resin composition of the present invention, from the viewpoint of obtaining excellent flexibility and toughness improvements while minimizing the decrease in flame retardancy due to the blending of the (c) olefinic elastomer, it is preferable that the PPS resin form a continuous phase in the phase structure of the PPS resin composition, and that the (c) olefinic elastomer form a dispersed phase in which the number-average dispersed particle size is 1.0 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.3 μm or less. As for the lower limit, the finer the dispersed particle size, the smaller the dispersed particle size, which is approximately 1 nm, the minimum dispersed particle size of a substantially incompatible system. In order to form a dispersed phase in which the (c) olefinic elastomer is dispersed in which the number-average dispersed particle size is 1.0 μm or less, it is preferable that the (c) olefinic elastomer has a reactive functional group, for example.

[0095] The number average dispersed particle diameter of (c) the olefin-based elastomer is determined by molding an ISO527-1-1A test piece at a molding temperature that is 20 to 40°C above the peak melting temperature of the PPS resin that constitutes component (a), cutting thin pieces of 0.1 μm or less from the center of the piece at room temperature in a cross-sectional direction perpendicular to the direction of resin flow during molding, and observing them at 1000 to 5000 times magnification with a Hitachi High-Technologies field emission scanning electron microscope SU8220.First, the maximum and minimum diameters of 100 randomly selected olefin-based elastomer particles are measured, the average value is taken as the dispersed particle diameter, and then the average of these is calculated.

[0096] (3)(b) Silicone-based polymer compound (component (b)) The inclusion of the silicone polymer compound (b) in the PPS resin composition according to an embodiment of the present invention is essential for achieving excellent flexibility and toughness in the resin composition, as well as flame retardancy.

[0097] The (b) silicone polymer compound is a high molecular weight compound containing siloxane bonds in the main chain structure, and specific examples include silicone gum, silicone elastomer, silicone resin, copolymer containing organopolysiloxane, and composite containing organopolysiloxane. Note that the polymer compound here refers to a compound in which the degree of polymerization of the organopolysiloxane is 100 or more and the weight average molecular weight is about 10,000 or more.

[0098] Silicone gum, silicone elastomer, and silicone resin are all polymeric silicones with organopolysiloxane as the basic skeleton. Depending on the degree of three-dimensional network structure, they are called silicone gum if they have no three-dimensional network structure, silicone elastomer if they have a slight three-dimensional network structure, and silicone resin if they have a strong three-dimensional network structure. Copolymers containing organopolysiloxane include copolymers of an organopolysiloxane component with one or more copolymerization components selected from polyolefins (e.g., polyethylene, polypropylene, polybutylene), polycarbonate, polyamide, polybutylene terephthalate, polyester elastomer, polystyrene, polyetherimide, polyketone, liquid crystal polymer, polyetherketone, polyetheretherketone, and polyacrylates (e.g., polymethyl methacrylate). More preferred copolymerization components are polyolefins, polycarbonates, polyetherimides, and polyacrylates. Examples of composites containing organopolysiloxane include core-shell rubbers in which silicone elastomer particles are covered with an acrylic component (silicone acrylic core-shell rubbers), and composite powders in which silicone elastomer particles are covered with a silicone resin.

[0099] The organopolysiloxane structure of the silicone gum, silicone elastomer, silicone resin, copolymer containing organopolysiloxane, core-shell compound containing organopolysiloxane, and composite containing organopolysiloxane preferably contains one or more hydrocarbon groups selected from alkyl groups (methyl, ethyl, propyl, butyl, 2-ethylbutyl, octyl, etc.), cycloalkyl groups (cyclohexyl, cyclopentyl, etc.), alkenyl groups (vinyl, propenyl, butenyl, heptenyl, hexenyl, allyl, etc.), and aryl groups (phenyl, tolyl, xylyl, naphthyl, diphenyl, etc.), and more preferably contains methyl or phenyl groups.

[0100] Furthermore, from the viewpoint of enhancing compatibility with PPS resins or olefin-based elastomers, it is preferable for the organopolysiloxane structure to contain one or more functional groups selected from alkoxyl groups (such as methoxy, ethoxy, propoxy, and butoxy groups), amino groups, epoxy groups, carbinol groups, methacryl groups, ether groups, mercapto groups, carboxyl groups, phenol groups, silanol groups, acrylic groups, carboxylic anhydride groups, polyether groups, aralkyl groups, fluoroalkyl groups, long-chain alkyl groups, higher fatty acid ester groups, and higher fatty acid amide groups, at the molecular chain terminals or molecular chain side chains. Among these, alkoxyl groups, amino groups, epoxy groups, methacryl groups, mercapto groups, carboxyl groups, and acrylic groups are preferred, with alkoxyl groups, epoxy groups, and methacrylic groups being particularly preferred.

[0101] The shape of the silicone polymer compound is not particularly limited, and examples thereof include pellets, bulk, powder, powder aggregates, flakes, liquid, and gum. From the viewpoints of handleability, processability, and dispersibility, pellets, powder, powder aggregates, and flakes are preferred.

[0102] Among these (b) silicone polymer compounds, those having a three-dimensional network structure, i.e., silicone elastomers and silicone resins, are preferred from the viewpoint of excellent flexibility, flame retardancy, and dispersibility in the resin composition, and silicone elastomers are particularly preferred from the viewpoint of a balance between flexibility and flame retardancy. Among these, silicone core-shell rubbers are preferred, and silicone acrylic core-shell rubbers are particularly preferred.

[0103] From the viewpoints of dispersibility, flame retardancy, and toughness of the PPS resin composition, the average primary particle diameter of the (b) silicone polymer compound itself is preferably 3.0 μm or less, more preferably 2.0 μm or less, even more preferably 1.0 μm or less, and particularly preferably 0.5 μm or less. The average primary particle diameter (number average particle diameter) of the (b) silicone polymer compound itself can be calculated by randomly selecting 100 particle diameters from a scanning electron microscope photograph and calculating the arithmetic average. If the particle diameter is not perfectly circular, such as elliptical, in the photograph, the maximum diameter of the particle is taken as the particle diameter.

[0104] When a (b) silicone-based polymer compound having an average primary particle size of 3.0 μm or less is used, the melt viscosity of the PPS resin composition can be increased by, for example, using a (c) olefin-based elastomer in combination with the PPS resin composition or by using a PPS resin with a high melt viscosity. This increases the melt viscosity of the PPS resin composition, forming a dispersed phase in which the (b) component has a number-average dispersed particle size of 3.0 μm or less, improving toughness and flame retardancy. Furthermore, in melt-kneading using a twin-screw extruder, an L / D ratio of 20 or more, two or more kneading sections, and a screw rotation speed of 200 to 500 rpm are also preferred conditions for achieving the desired number-average dispersed particle size of the (b) component. Combining these methods is particularly preferred.

[0105] On the other hand, even when a (b) silicone polymer compound having an average primary particle size of 3.0 μm or less is used, if the melt viscosity of the resin composition is low or if the kneading strength during melt kneading in a twin-screw extruder is insufficient, it may become difficult to obtain the desired number average dispersed particle size due to aggregation of component (b), and toughness and flame retardancy may be reduced. Furthermore, in the morphology (phase structure) of the PPS resin composition of the present invention, if component (b) exists in the form of aggregates, the aggregated portions are considered to be one dispersed phase.

[0106] The content of the (b) silicone polymer compound used in the present invention must be 3 to 40 parts by weight per 100 parts by weight of the PPS resin constituting component (a), preferably 5 to 37 parts by weight, more preferably 7.5 to 35 parts by weight, even more preferably 8 to 30 parts by weight, and particularly preferably 9 to 25 parts by weight. If the amount of silicone polymer compound exceeds 40 parts by weight per 100 parts by weight of PPS resin, the silicone polymer compound tends to coarsen in the PPS resin, resulting in a decrease in toughness and flame retardancy. On the other hand, if the amount of silicone polymer compound is less than 3 parts by weight per 100 parts by weight of PPS resin, the resin composition will not have sufficient flexibility, toughness, and flame retardancy, which is undesirable.

[0107] It is also preferable to use two or more types of silicone polymer compounds in combination, from the viewpoint of achieving a good balance of flexibility, toughness and flame retardancy and improving dispersibility.

[0108] (4)(d) Other additives Furthermore, resins other than component (a), component (b), and (c) olefin-based elastomer may be added to the PPS resin composition of the present invention, provided that the effects of the present invention are not impaired. Specific examples include, but are not limited to, polyamide, polyamide elastomer, polybutylene terephthalate, polyethylene terephthalate, polyester elastomer, polyetherimide, polyketone, liquid crystal polymer, polyether ketone, polyether ether ketone, ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and styrene-based elastomer. The amount of such resin added is preferably less than 20 parts by weight, more preferably less than 15 parts by weight, and even more preferably less than 10 parts by weight, per 100 parts by weight of PPS resin. The lower limit is preferably 0 parts by weight, ie, no resins are included.

[0109] The blending of other resins is thought to form a phase separation structure with the PPS resin, leading to a decrease in toughness due to a decrease in adhesion, so it is preferable to set the blending amount of other resins within the above range.

[0110] To improve flame retardancy, phosphorus-based flame retardants, halogen-based flame retardants, and inorganic flame retardants can be added to the PPS resin composition of the present invention. Phosphorus-based flame retardants are flame retardants containing phosphorus, such as aromatic phosphate ester compounds, phosphazene compounds, phosphaphenanthrene compounds, metal phosphinates, phosphonic acid polymers, ammonium polyphosphate, melamine polyphosphate, phosphate ester amides, and red phosphorus. Halogen-based flame retardants include brominated epoxy resins, brominated polystyrene, brominated polycarbonate, and brominated polyphenylene ether. Inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, zinc hydroxide, and titanium hydroxide. A flame retardant aid can also be used to enhance the flame retardancy of these flame retardants. Specific examples include antimony compounds and nitrogen-containing compounds.

[0111] The PPS resin composition of the present invention can contain the following compounds for the purpose of modifying its properties: Plasticizers such as polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, and organophosphorus compounds; nucleating agents such as organophosphorus compounds and polyether ether ketone; metal soaps such as Montan acid waxes, lithium stearate, and aluminum stearate; release agents such as ethylenediamine-stearic acid-sebacic acid polycondensates and silicone compounds; and other common additives such as water, lubricants, UV inhibitors, color inhibitors, colorants, and foaming agents. More than 10 parts by weight of any of the above compounds in the total composition is undesirable because it impairs the inherent properties of the PPS resin composition of the present invention. Addition of no more than 5 parts by weight, and more preferably no more than 1 part by weight, is recommended.

[0112] In the present invention, a compatibilizer can be used in combination to enhance the compatibility between the resins. Specific examples include organic silane compounds and epoxy resins.

[0113] Specific examples of the organic silane compound include an organic silane compound having at least one functional group selected from an isocyanate group, an epoxy group, an amino group, a hydroxyl group, a mercapto group, a ureido group, and an alkoxy group. Specific examples include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, and N-phenylaminomethyltrimethoxysilane. Preferred examples of the silane include N-phenylaminopropyltrimethoxysilane, dimethoxymethyl-3-piperazinopropylsilane, 3-piperazinopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 3-isocyanatopropylethyldimethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptomethyldimethoxysilane, and γ-ureidopropyltrimethoxysilane.

[0114] Among the above-mentioned organic silane compounds, 3-isocyanatopropyltriethoxysilane, 3-aminopropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane are preferred from the viewpoints of reactivity and ease of handling.

[0115] These alkoxy organic silane compounds can be used alone or in the form of a mixture of two or more kinds.

[0116] The amount of the organosilane compound used in the present invention is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, and even more preferably 0.3 to 3 parts by weight, per 100 parts by weight of the PPS resin constituting component (a). A blending amount of the organosilane compound of 10 parts by weight or less is preferred because it allows the flame retardancy of the resulting PPS resin composition to be maintained. A blending amount of the organosilane compound of 0.01 parts by weight or more is preferred because it allows sufficient reaction between the PPS resin and the organosilane compound, allowing excellent toughness to be achieved.

[0117] Specific examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, brominated epoxy resins, special skeleton bifunctional epoxy resins having a biphenyl skeleton or a naphthalene skeleton, glycidyl ether epoxy resins such as cresol novolac, trisphenolmethane, and dicyclopentadiene polyfunctional epoxy resins, glycidyl amine epoxy resins such as aromatic amine and aminophenol types, and glycidyl ester epoxy resins such as hydrophthalic acid and dimer acid types. The amount of such epoxy resins added is preferably 0.1 to 5 parts by weight, and more preferably 0.2 to 3 parts by weight, per 100 parts by weight of the total PPS resin composition.

[0118] Although not an essential component, inorganic fillers can be blended and used in the PPS resin composition of the present invention within the scope that does not impair the effects of the present invention. Specific examples of such inorganic fillers include fibrous fillers such as glass fiber, carbon fiber, carbon nanotube, carbon nanohorn, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, and metal fiber; fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, asbestos, and aluminum. Examples of fillers that can be used include silicates such as silicate 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, and non-fibrous fillers such as silica and graphite. Of these, glass fiber, silica, and calcium carbonate are preferred, with calcium carbonate and silica being particularly preferred from the perspective of corrosion prevention and lubricating properties. These inorganic fillers may be hollow, and two or more types may be used in combination. These inorganic fillers may also be pretreated with coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds. Among these, calcium carbonate, silica, and carbon black are preferred from the perspective of corrosion prevention and lubricating properties.

[0119] The amount of inorganic filler to be added is selected to be less than 10 parts by weight, preferably less than 5 parts by weight, more preferably less than 3 parts by weight, and even more preferably 1 part by weight or less, per 100 parts by weight of the total PPS resin composition. There is no particular lower limit, but 0.0001 parts by weight or more is preferred. While the addition of inorganic fillers is effective in improving the strength of the material, adding more than 10 parts by weight is undesirable because it reduces toughness and flexibility. The addition of inorganic fillers such as glass fiber significantly increases the flexural modulus, making it difficult to obtain a polyphenylene sulfide resin composition that combines toughness, flexibility, and flame retardancy. Furthermore, in the present invention, the addition of inorganic fillers such as glass fiber tends to reduce flame retardancy.

[0120] (5) Method for producing PPS resin composition Methods for producing the PPS resin composition of the present invention include production in a molten state and production in a solution state, but production in a molten state is preferred from the viewpoint of simplicity. For production in a molten state, melt kneading using an extruder or melt kneading using a kneader can be used, but from the viewpoint of productivity, melt kneading using an extruder that allows continuous production is preferred. For melt kneading using an extruder, at least one extruder can be used, such as a single-screw extruder, a twin-screw extruder, a multi-screw extruder such as a four-screw extruder, or a twin-screw single-screw composite extruder. However, from the viewpoints of kneading ability, reactivity, and improved productivity, multi-screw extruders such as a twin-screw extruder and a four-screw extruder are preferred, and melt kneading using a twin-screw extruder is most preferred.

[0121] A more specific method of melt-kneading is, but is not necessarily limited to, a twin-screw extruder having an L / D (L: screw length, D: screw diameter) ratio of 10 or more, preferably 20 or more, and two or more, preferably three or more kneading sections. There is no particular upper limit to the L / D ratio, but from an economical standpoint, it is preferable that it be 60 or less. There is also no particular upper limit to the number of kneading sections, but from a productivity standpoint, it is preferable that it be 10 or less. The ratio of the kneading sections to the total screw length is preferably 15% or more, more preferably 20% or more, and even more preferably 30% or more. If the ratio of the kneading sections to the total screw length is less than 15%, the kneading power will be poor, resulting in a coarse number-average dispersed particle size of the (b) silicone polymer compound, and the desired physical properties will not be achieved. On the other hand, the upper limit of the ratio of the kneading sections to the total screw length is preferably 70% or less, from the standpoint of preventing deterioration of the resin due to excessive shear heat generation during kneading.

[0122] The screw rotation speed is preferably 150 to 1,000 rpm, preferably 150 to 600 rpm, more preferably 150 to 500 rpm, and particularly preferably 200 to 500 rpm. When the screw rotation speed exceeds 150 rpm, the kneading force is sufficient, resulting in a finer number-average dispersed particle size of the (b) silicone polymer compound, which leads to the development of desired toughness. When the screw rotation speed exceeds 1,000 rpm, excessive shear heat generation during kneading can cause deterioration of the resin and additives, leading to reduced toughness, reduced mold fouling, and reduced melt viscosity that can lead to reduced molding processability, such as the generation of flash.

[0123] The cylinder temperature is preferably in the range of +5 to +100°C relative to the melting point of the PPS resin constituting component (a), which is 250 to 280°C, and more specifically in the range of 280 to 400°C, more preferably in the range of 280 to 360°C, and even more preferably in the range of 280 to 330°C.

[0124] The order of mixing the raw materials when melt-kneading is not particularly limited, and any of the following methods may be used: a method in which all raw materials are mixed and then melt-kneaded by the above method; a method in which some raw materials are mixed and then melt-kneaded by the above method, and then the remaining raw materials are mixed and melt-kneaded; or a method in which some raw materials are mixed and then the remaining raw materials are mixed using a side feeder while being melt-kneaded by a twin-screw extruder.

[0125] (6) PPS resin composition The polyphenylene sulfide resin composition of the present invention must have a flexural modulus, which is one of the physical properties that indicates the flexibility of a material (measured in accordance with ISO 178 using test pieces obtained by injection molding at a cylinder temperature of 310°C and a mold temperature of 145°C, bending speed of 2 mm / min, 23°C), of 3.0 GPa or less, preferably 2.8 GPa or less, more preferably 2.5 GPa or less, and particularly preferably 2.3 GPa or less. For hollow piping components, flexibility is required from the standpoints of bending processability during piping component manufacture and actual use, and prevention of breakage when a joint component is press-fitted into the piping component. Therefore, the flexural modulus of the resin composition is required to be 3.0 GPa or less. From the standpoint of flexibility, the lower the flexural modulus, the better. There is no particular lower limit, but an example is 0.1 GPa or more, at which the shape can be substantially maintained. There are no particular limitations on the method for obtaining a PPS resin composition having such properties. For example, the resin composition may contain 1 to 40 parts by weight of (c) olefin-based elastomer per 100 parts by weight of the PPS resin constituting component (a), or the resin composition may contain 3 to 40 parts by weight of (b) silicone-based polymer compound.

[0126] The PPS resin composition of the present invention must have a flame retardancy of V-0 when measured using test specimens 1.6 mm thick or less according to the UL94 standard, which is an index of the flame retardancy of materials. V-0 is also preferred for test specimens 1.0 mm thick or less, and V-0 is also preferred for test specimens 0.5 mm thick or less. Generally, the thicker the test specimen, the more excellent the flame retardancy. However, the PPS resin composition of the present invention exhibits V-0 flame retardancy even for test specimens 1.6 mm thick or less. Possessing such flame retardancy means that molded articles can be made thinner and therefore lighter while still retaining excellent flame retardancy. This not only contributes to reducing human and economic losses due to fires, but also contributes to energy savings due to the reduced weight, making it suitable for use in automotive components, such as electric vehicles. There are no particular limitations on the method for obtaining a PPS resin composition having such properties. For example, the content of component (b) in the resin composition is 3 parts by weight or more and 40 parts by weight or less per 100 parts by weight of component (a), or component (b) forms a finely dispersed structure in the PPS resin composition having a number average dispersed particle diameter of 3.0 μm or less.

[0127] The tensile elongation at break of the PPS resin composition of the present invention (dumbbell test piece (ISO 527-2-1A), tensile speed 50 mm / min, 23°C, conforming to ISO 527-1,2 (2012)), which is one of the physical properties that indicate the toughness of a material, is preferably 10% or more, more preferably 12.5% ​​or more, even more preferably 15% or more, and particularly preferably 20% or more. Furthermore, 25% or more is preferable. From the viewpoint of preventing breakage of hollow piping components and various molded products during actual use, it is desirable that the tensile elongation at break of a molded product of the resin composition be 10% or more. From the viewpoint of preventing breakage of components during actual use, a higher tensile elongation at break is preferable, and although there is no particular upper limit, it can be, for example, substantially 500% or less. There are no particular limitations on the method for obtaining a PPS resin composition having such properties. For example, the amount of (c) olefin-based elastomer blended relative to 100 parts by weight of the PPS resin constituting component (a) may be 1 part by weight or more and 40 parts by weight or less, or the content of (b) silicone-based polymer compound may be 3 parts by weight or more and 40 parts by weight or less, or component (b) may form a finely dispersed structure in the PPS resin with a number average dispersed particle diameter of 3.0 μm or less.

[0128] The PPS resin composition of the present invention exhibits excellent flame retardancy even when the flexibility and toughness of the PPS resin are improved by the inclusion of a silicone-based polymer compound. To achieve these properties, it is essential that the PPS resin constituting component (a) form a continuous phase and the silicone-based polymer compound (b) form a dispersed phase in which the number-average dispersed particle size is 3.0 μm or less. In the phase structure of the PPS resin composition, component (a) preferably forms a continuous phase and component (b) forms a dispersed phase in which the number-average dispersed particle size is 2.0 μm or less. The number-average dispersed particle size of component (b) as the dispersed phase is more preferably 1.0 μm or less, and particularly preferably 0.5 μm or less. While a smaller dispersed particle size is preferable, the lower limit is approximately 1 nm, which is the minimum dispersed particle size for a substantially incompatible system. On the other hand, a number-average dispersed particle size exceeding 3.0 μm indicates poor dispersion of the silicone-based polymer compound in the resin composition, resulting in the formation of relatively large aggregates. This dispersion state is considered undesirable because it can become the starting point for fracture in tensile tests and bending tests. Furthermore, the presence of a relatively coarse dispersed phase of the silicone polymer compound is undesirable because it is believed that combustion based on this dispersed phase will occur and continue, resulting in a decrease in flame retardancy. A preferred method for controlling the number-average dispersed particle size of the silicone polymer compound in the PPS resin composition to 3.0 μm or less is to melt-knead at least components (a) and (b) in a twin-screw extruder, setting the L / D ratio to 20 or more, providing two or more kneading zones, and satisfying the screw rotation speed requirements of 200 to 500 rpm. Another preferred method for controlling the number-average dispersed particle size of the silicone polymer compound to 3.0 μm or less is to maintain the melt viscosity of the PPS resin composition at 400 Pa·s or higher. Preferred methods for achieving a melt viscosity of 400 Pa·s or higher in the PPS resin composition include, for example, using an olefin-based elastomer (c) in combination with the PPS resin composition or using a PPS resin with a high melt viscosity. In order to control the number average dispersed particle size of the silicone polymer compound to 3.0 μm or less, it is particularly preferable to employ the melt-kneading method described above in combination with adjusting the melt viscosity of the PPS resin composition to 400 Pa s or more.From the viewpoint of achieving a finer number-average dispersed particle size of the silicone polymer compound and obtaining excellent toughness and flame retardancy, the melt viscosity of the PPS resin composition is preferably 500 Pa·s or more, even more preferably 800 Pa·s or more, and particularly preferably 1200 Pa·s or more. From the viewpoint of maintaining melt fluidity, the upper limit of the melt viscosity of the PPS resin composition is preferably 3000 Pa·s or less. Furthermore, within this melt viscosity range, the higher the melt viscosity of the PPS resin composition, the better the take-up of the molten resin during extrusion molding and the more likely the appearance of the extrusion-molded product will be.

[0129] The number-average dispersed particle size here refers to a value obtained by molding an ISO 527-1-1A test piece at a molding temperature of 20 to 40°C above the peak melting temperature of the PPS resin, cutting a thin piece of 0.1 μm or less from the center of the piece at room temperature in a cross-sectional direction perpendicular to the resin flow direction during molding, and observing the piece at 1000 to 5000 times magnification using a Hitachi High-Technologies SU8220 field emission scanning electron microscope. First, the maximum and minimum diameters of 100 randomly selected silicone polymer compounds were measured, and the average was taken as the dispersed particle size. In the morphology (phase structure) of the PPS resin composition of the present invention, when component (b) exists in aggregate, the aggregated portions are considered to be one dispersed phase.

[0130] The melt viscosity of the PPS resin composition of the present invention was measured using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10, at a shear rate of 122 s -1 is the value at

[0131] (7) Uses of PPS resin compositions The polyphenylene sulfide resin composition of the present invention can be molded by various molding techniques, such as injection molding, extrusion molding, compression molding, blow molding, and injection-compression molding, and is particularly useful for extrusion molding or injection molding. In particular, the polyphenylene sulfide resin composition of the present invention combines excellent flexibility and toughness, making it suitable for hollow piping components, particularly for piping components such as ducts and cooling tubes for automotive applications, which require heat resistance and low water absorption, and for piping components for plumbing applications in housing facilities. It is also suitable for piping components for urban air mobility applications, which require both high performance and lightweight properties. Furthermore, the polyphenylene sulfide resin composition of the present invention possesses flame retardancy, a characteristic of the composition, enabling greater safety to be achieved in these applications.

[0132] Applications of molded products obtained by injection molding include electrical equipment parts such as generators, electric motors, transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, circuit breakers, knife switches, polarity rods, electrical component cabinets, sensors, LED lamps, connectors, sockets, resistors, relay cases, small switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystal displays, FDD (Floppy Disk Drive) carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts, and other electronic components such as VTRs (Video Tape Recorder parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio, laser discs (registered trade name), and compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, and other household and office electrical appliance parts; office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, motor parts, lighters, typewriters, and other machinery related parts; optical equipment and precision machinery related parts such as microscopes, binoculars, cameras, and watches;Alternator terminals, alternator connectors, IC regulators, potentiometer bases for light dimmers, various valves such as exhaust gas valves, various pipes and ducts for fuel, exhaust and intake systems, turbo ducts, air intake nozzle snorkels, intake manifolds, fuel pumps, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, brake pad wear sensors, throttle position sensors, crankshaft position sensors, air flow meters, brake pad wear sensors, air conditioner thermostat bases, heating hot air flow control valves, brush holders for radiator motors, water pump inlets Examples include automobile and vehicle-related parts such as impellers, turbine vanes, wiper motor-related parts, distributors, starter switches, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioner panel switch boards, fuel-related electromagnetic valve coils, fuse connectors, horn terminals, electrical component insulating plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, crash pads, insulation ties, and ignition device cases; gaskets for primary or secondary batteries in mobile phones, smartphones, notebook computers, tablet computers, video cameras, hybrid cars, electric cars, etc.;

[0133] Examples of molded products obtainable by extrusion molding include round bars, square bars, sheets, films, tubes, and pipes. More specific examples of uses include electrical insulating materials for water heater motors, air conditioner motors, and drive motors, film capacitors, speaker diaphragms, recording magnetic tape, printed circuit board materials, printed circuit board peripheral parts, seamless belts, semiconductor packages, semiconductor carrier trays, process and release films, protective films, automotive film sensors, insulating tape for wire cables, insulating washers in lithium-ion batteries, tubing for hot water, coolant, and chemicals, automotive fuel tubing, hot water, coolant, chemical, and fuel tubing for urban air mobility, hot water piping, chemical piping for chemical plants, piping for ultrapure water and ultrahigh-purity solvents, automotive piping, piping for chlorofluorocarbons and supercritical carbon dioxide refrigerants, and workpiece retaining rings for polishing equipment. Other examples include coated molded articles for windings of motor coils in hybrid vehicles, electric vehicles, fuel cell vehicles, railways, and power generation facilities; heat-resistant electric cables for home appliances; wire harnesses and control wires such as flat cables used for wiring inside automobiles; and coated molded articles for windings of signal transformers or on-board transformers for communication, transmission, high frequency, audio, measurement, etc.

[0134] Examples of uses for molded articles obtained by blow molding include automobile fuel tanks, oil tanks, resonators, intercoolers, intake manifolds, turbo ducts, intake and exhaust ducts, radiator pipes, radiator headers, expansion tanks, and oil circulation pipes.

[0135] These various molded products can of course be subjected to secondary processing such as hot plate welding, laser welding, induction heating welding, high frequency welding, spin welding, vibration welding, ultrasonic welding, and injection welding. [Example]

[0136] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.

[0137] In the examples and comparative examples, the following were used as (a) polyphenylene sulfide resin, (b) silicone polymer compound, (c) olefin elastomer, and (d) other additives.

[0138] [(a) Polyphenylene sulfide resin (a-1, a-2, a-3, a-4, a-5)] [Reference example 1 PPS resin (a-1)] An autoclave equipped with a stirrer was charged with 8267.37 g (70.00 mol) of 47.5% sodium hydrosulfide, 2923.88 g (70.17 mol) of 96% sodium hydroxide, 11434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1894.20 g (23.10 mol) of sodium acetate, and 10500 g of ion-exchanged water. The mixture was gradually heated to 230 °C over approximately 3 hours under atmospheric pressure while passing nitrogen through. After distilling off 14780.1 g of water and 280 g of NMP, the reaction vessel was cooled to 160 °C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.017 mol per mole of charged alkali metal sulfide.

[0139] Next, 10458.90 g (71.15 mol) of p-dichlorobenzene and 9078.30 g (91.70 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, the temperature was increased to 240 ° C at a rate of 0.6 ° C / min. After 40 minutes of reaction at 240 ° C., the temperature was increased to 275 ° C. at a rate of 0.8 ° C. / min. Then, 2394 g (133 mol) of ion-exchanged water was pressure-charged into the autoclave while cooling to 250 ° C. at a rate of 1.3 ° C. / min. The mixture was then cooled to 200 ° C. at a rate of 1.0 ° C. / min., and then rapidly cooled to near room temperature.

[0140] The contents were removed and diluted with 26,300 g of NMP. The solvent and solids were filtered through an 80-mesh sieve, and the resulting particles were washed with 31,900 g of NMP and filtered. These were washed several times with 56,000 g of ion-exchanged water and filtered, and then washed with 70,000 g of 0.05 wt% acetic acid aqueous solution and filtered. After washing with 70,000 g of ion-exchanged water and filtering, the resulting hydrous PPS particles were dried with hot air at 80°C and then dried under reduced pressure at 120°C. The resulting PPS resin (a-1) had a non-Newtonian index of 1.25, a weight-average molecular weight of 54,000, a melting point of 280°C, a carboxyl group content of 42 μmol / g, and a melt viscosity of 170 Pa·s.

[0141] [Reference example 2 PPS resin (a-2)] An autoclave equipped with a stirrer and a bottom stop valve was charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), and 10.5 kg of ion-exchanged water. The mixture was gradually heated to 245°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. After distilling off 14.78 kg of water and 0.28 kg of NMP, the reactor was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 mol per mole of charged alkali metal sulfide.

[0142] The mixture was then cooled to 200°C, and 10.48 kg (71.27 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas and heated from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting at 270°C for 100 minutes, the bottom stopper valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen. The mixture was then stirred at 250°C for a while to remove most of the NMP.

[0143] The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction-filtered through a glass filter. Next, 76 liters of ion-exchanged water heated to 70°C was poured into the glass filter and suction-filtered to obtain a cake.

[0144] The obtained cake and 90 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was purged with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. The autoclave was then cooled, and the contents were removed.

[0145] The contents were filtered through a glass filter with suction, and then 76 liters of 70°C ion-exchanged water was poured into the filter and filtered with suction to obtain a cake. The resulting cake was dried at 120°C under a nitrogen stream to obtain dried PPS. It was then heat-treated at 200°C under an oxygen stream to obtain crosslinked PPS resin (a-2). The resulting PPS resin (a-2) had a non-Newtonian index of 1.45, a weight-average molecular weight of 56,000, a melting point of 280°C, a carboxyl group content of 25 μmol / g, and a melt viscosity of 155 Pa s.

[0146] [Reference example 3 PPS resin (a-3)] An autoclave equipped with a stirrer was charged with 8267.37 g (70.00 mol) of 47.5% sodium hydrosulfide, 2923.88 g (70.17 mol) of 96% sodium hydroxide, 11434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1894.20 g (23.10 mol) of sodium acetate, and 10500 g of ion-exchanged water. The mixture was gradually heated to 230 °C over approximately 3 hours under atmospheric pressure while passing nitrogen through. After distilling off 14780.1 g of water and 280 g of NMP, the reaction vessel was cooled to 160 °C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.017 mol per mole of charged alkali metal sulfide.

[0147] Next, 10,420 g (70.89 mol) of p-dichlorobenzene and 9078.30 g (91.70 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, the temperature was increased to 240 ° C at a rate of 0.6 ° C / min. After 40 minutes of reaction at 240 ° C, the temperature was increased to 275 ° C at a rate of 0.8 ° C / min. 2,394 g (133 mol) of ion-exchanged water was then pressure-charged into the autoclave while cooling to 250 ° C at a rate of 1.3 ° C / min. The mixture was then cooled to 200 ° C at a rate of 1.0 ° C / min and then rapidly cooled to near room temperature.

[0148] The contents were removed and diluted with 26,300 g of NMP. The solvent and solids were filtered through an 80-mesh sieve, and the resulting particles were washed with 31,900 g of NMP and filtered. These were washed several times with 56,000 g of ion-exchanged water and filtered, and then washed with 70,000 g of 0.05 wt.% acetic acid aqueous solution and filtered. After washing with 70,000 g of ion-exchanged water and filtering, the resulting hydrous PPS particles were dried with hot air at 80°C and then dried under reduced pressure at 120°C. The resulting PPS resin (a-3) had a non-Newtonian index of 1.35, a weight-average molecular weight of 73,000, a melting point of 280°C, a carboxyl group content of 35 μmol / g, and a melt viscosity of 398 Pa·s.

[0149] [Reference example 4 PPS resin (a-4)] An autoclave equipped with a stirrer was charged with 8.26 kg (70.0 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.6 mol) of 96% sodium hydroxide, 11.45 kg (115.5 mol) of N-methyl-2-pyrrolidone (NMP), 1.61 kg (19.6 mol) of sodium acetate, and 5.50 kg of ion-exchanged water. The mixture was gradually heated to 240 °C under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling commenced when 9.82 kg of water and 0.28 kg of NMP had distilled. At this point, the amount of water remaining in the system per mole of alkali metal hydrosulfide charged was 1.01 mol, including the water consumed in the hydrolysis of NMP. Furthermore, the amount of hydrogen sulfide released was 1.4 mol, so the amount of sulfiding agent in the system after this dehydration step was 68.6 mol. Note that, with the release of hydrogen sulfide, an additional 1.4 mol of sodium hydroxide was generated in the system.

[0150] Next, 10.33 kg (70.2 mol) of p-dichlorobenzene (p-DCB), 0.044 kg (0.24 mol) of 1,2,4-trichlorobenzene (TCB), and 9.37 kg (94.5 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. The temperature was raised from 200°C to 270°C with stirring, and the temperature was maintained at 270°C for 180 minutes to carry out the polymerization reaction. After the reaction was completed, the mixture was cooled to 200°C at a rate of 1.0°C / min and then rapidly cooled to near room temperature. The mixture was diluted with NMP to form a slurry, which was stirred at 85°C for 30 minutes and then filtered through an 80-mesh wire mesh to obtain a solid. The resulting solid was similarly washed with NMP and filtered. The resulting solid was diluted with ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80-mesh wire mesh to collect the solid. This procedure was repeated four times. The PPS resin was then washed in an aqueous solution containing 0.5% by weight of calcium acetate per 1 g of PPS resin, and the solid matter was recovered by filtration through an 80-mesh wire screen. After further washing with ion-exchanged water and filtering, the resulting hydrated PPS particles were dried with hot air at 80°C and then dried under reduced pressure at 120°C. The resulting PPS resin (a-4) had a non-Newtonian index of 2.05, a weight-average molecular weight of 90,000, a melting point of 275°C, and a melt viscosity of 2,761 Pa s.

[0151] [Reference example 5 PPS resin (a-5)] An autoclave equipped with a stirrer was charged with 8267.37 g (70.00 mol) of 47.5% sodium hydrosulfide, 2962.50 g (71.10 mol) of 96% sodium hydroxide, 11434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 516.60 g (6.30 mol) of sodium acetate, and 10,500 g of ion-exchanged water. The mixture was gradually heated to 230 °C over approximately 3 hours under atmospheric pressure while passing nitrogen through the mixture. After distilling off 14,780.1 g of water and 280 g of NMP, the reaction vessel was cooled to 160 °C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.017 mol per mole of charged alkali metal sulfide. Next, 10,363.50 g (70.50 mol) of p-dichlorobenzene and 9078.30 g (91.70 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, the temperature was raised to 270 °C at a rate of 0.6 °C / min and maintained at 270 °C for 140 minutes. Then, 2,520 g (140 mol) of ion-exchanged water was pressure-charged into the autoclave while cooling to 250 °C at a rate of 1.3 °C / min. The contents were then cooled to 200 °C at a rate of 1.0 °C / min and then rapidly cooled to near room temperature. The contents were removed and diluted with 26,300 g of NMP. The solvent and solids were filtered off using an 80 mesh sieve, and the resulting particles were washed with 31,900 g of NMP and filtered off. The resulting hydrated PPS particles were washed several times with 56,000 g of ion-exchanged water, filtered, and then washed with 70,000 g of 0.05 wt% acetic acid aqueous solution and filtered. After washing with 70,000 g of ion-exchanged water and filtering, the resulting hydrated PPS particles were dried with hot air at 80°C and then dried under reduced pressure at 120°C. The resulting PPS resin (a-5) had a non-Newtonian index of 1.10, a weight-average molecular weight of 42,000, a melting point of 280°C, a carboxyl group content of 45 μmol / g, and a melt viscosity of 74 Pa s.

[0152] [Reference Example 6: Mixture of PPS resin (a-3) (83 wt%) and PPS resin (a-4) (17 wt%)] Non-Newtonian index: 1.50, melting point: 280°C, melt viscosity: 560 Pa·s.

[0153] [Reference Example 7: Mixture of PPS resin (a-3) (50% by weight) and PPS resin (a-4) (50% by weight)] Non-Newtonian index: 1.75, melting point: 280°C, melt viscosity: 890 Pa·s.

[0154] [(b) Silicone polymer compounds (b-1, b-2, b-3)] b-1: Silicone-acrylic core-shell rubber (Kane Ace MR-01 manufactured by Kaneka Corporation), average primary particle size: 0.13 μm b-2: Methacrylic group-modified silicone elastomer powder (Dow EP-2720), average primary particle size: 1.8 μm b-3: Epoxy-terminated polydimethylsiloxane.

[0155] [(c) Olefin-based elastomer (c-1)] c-1: Ethylene-glycidyl methacrylate copolymer (olefin resin manufactured by Sumitomo Chemical Co., Ltd., Bondfast E, melting point 103°C, MFR: 3g / 10min (190°C, 21.2N load)), reactive functional group content: 12% by weight.

[0156] [(d) Other additives (d-1, d-2)] d-1: 3-Isocyanatepropyltriethoxysilane (KBE-9007N, manufactured by Shin-Etsu Silicone Co., Ltd.) d-2: Glass fiber (T760H, manufactured by Nippon Electric Glass Co., Ltd.).

[0157] In the following examples, material properties were evaluated by the following methods.

[0158] [Bending test] PPS resin composition pellets were dried for 3 hours at 130°C using a hot air dryer and then fed into a Sumitomo Heavy Industries injection molding machine (SE-75DUZ) set at a cylinder temperature of 310°C and a mold temperature of 145°C. Using a mold with a Type A1 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 portion was 400±50 mm / s to obtain test specimens. The central parallel portion of this test specimen was cut out to obtain Type B2 test specimens. After conditioning this test specimen for 16 hours at 23°C and 50% relative humidity, the flexural modulus was measured according to ISO 178 (2010) at a span of 64 mm and a test speed of 2 mm / min.

[0159] [Flame retardancy test] PPS resin composition pellets were dried at 130°C for 3 hours using a hot air dryer and then fed into a Sumitomo Heavy Industries injection molding machine (SE-75DUZ) set at a cylinder temperature of 320°C and a mold temperature of 150°C to obtain test specimens for flame retardancy evaluation. The flame retardancy of the test specimens was evaluated according to the evaluation criteria specified in the UL94 vertical test. Flame retardancy is ranked in descending order of V-0 > V-1 > V-2. Test specimens that did not meet the V-2 standard were marked "out." Test specimens were used with thicknesses of 1.6 mm, 1.0 mm, and 0.5 mm.

[0160] [Tensile test] The Type A1 test specimens obtained in the same manner as in the bending test were conditioned for 16 hours at 23°C and 50% relative humidity, after which the tensile elongation (and strain) at break were measured in accordance with ISO 527-1,2 (2012) at a chuck distance of 114 mm and a test speed of 50 mm / min.

[0161] [Number average dispersed particle size of component (b)] A Type A1 specimen obtained in the same manner as in the bending test was cut at room temperature from the center of its central parallel section to form a thin section of 0.1 μm or less in thickness in a cross-sectional direction perpendicular to the resin flow direction during molding. The section was then observed at 1000 to 5000 times magnification using a Hitachi High-Technologies SU8220 field emission scanning electron microscope. For 100 randomly selected particles of component (b), the maximum and minimum diameters of each were measured, and the average was taken as the dispersed particle diameter of the particle. The average dispersed particle diameter of each particle was then calculated, and this was taken as the number-average dispersed particle diameter. When the silicone polymer compound of component (b) was present in aggregate, the aggregates were measured as a single dispersed phase, and the number-average dispersed particle diameter was calculated.

[0162] [(c) Number average dispersed particle size of olefin-based elastomer] A Type A1 test piece obtained in the same manner as for the bending test was cut at room temperature from the center of its central parallel section in a cross-sectional direction perpendicular to the direction of resin flow during molding of the dumbbell piece, and observed at 1000 to 5000 times magnification using a Hitachi High-Technologies SU8220 field emission scanning electron microscope. For 100 randomly selected (c) olefin-based elastomer particles, the maximum and minimum diameters of each were first measured, and the average value was taken as the dispersed particle size of that (c) olefin-based elastomer. The average dispersed particle size of each (c) olefin-based elastomer was then calculated, and this was taken as the number-average dispersed particle size.

[0163] [Non-Newtonian index] The non-Newtonian index of the PPS resin was determined by the following method: using a Toyo Seiki Co., Ltd. Capillograph 1B (capillary with a length of 10 mm and a diameter of 1 mm), the resin was subjected to shear at a temperature of 300°C and a shear rate of 60 to 6080 s -1 The shear stress at each shear rate was measured, and the non-Newtonian index was calculated by applying the relationship between shear rate and shear stress to the following equation (1).

[0164] SR=K·SS N ···(1) (where N is the non-Newtonian exponent, SR is the shear rate (1 / sec), and SS is the shear stress (dyne / cm 2 ), where K is a constant. [Melt viscosity] The melt viscosity of the PPS resin composition was determined by the following method: using a Toyo Seiki Co., Ltd. Capillograph 1B (capillary having a length of 10 mm and a diameter of 1 mm), the temperature was measured at 300°C under the conditions of orifice length L (mm) / orifice diameter D (mm) = 10, and the shear rate was 122 s -1 The values ​​at were adopted.

[0165] [GPC measurement] The number average molecular weight (Mn) and weight average molecular weight (Mw) of the PPS resin were measured using a gel permeation chromatography (GPC) manufactured by Senshu Scientific Co., Ltd. under the conditions shown below, and calculated in terms of polystyrene. Equipment: Senshu Science SSC-7110 Column name: Shodex UT806M x 2 Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210℃ Pre-thermostat temperature: 250℃ Pump thermostatic bath temperature: 50℃ Detector temperature: 210℃ Flow rate: 1.0mL / min Sample injection volume: 300 μL.

[0166] [Examples 1 to 6, 8 to 10, 12 to 21, Comparative Examples 1 to 13] PPS resin, olefin-based elastomer, silicone-based polymer compound, and other additives were dry-blended according to the formulations shown in Tables 1 to 3, and then melt-kneaded in a TEX30α twin-screw extruder (L / D = 30, 3 kneading sections) manufactured by The Japan Steel Works, Ltd. The kneading conditions were a temperature of 300°C and a rotation speed of 300 rpm. This kneading method is referred to as Method A (Tables 1 to 3). After pelletizing using a strand cutter, the pellets were dried at 130°C for 3 hours and then subjected to injection molding. The evaluation results for the number-average dispersed particle size, flexural modulus, flame retardancy, tensile elongation at break, and melt viscosity of the silicone-based polymer compound and olefin-based elastomer are shown in Tables 1 to 3.

[0167] [Examples 7 and 11] Melt-kneading was carried out under the same conditions as in Example 1, except that the kneading section was set to one location, to obtain resin composition pellets, and various properties were evaluated. The melt-kneading method under these conditions is referred to as Method B. The results are shown in Tables 1 and 2.

[0168] [Table 1]

[0169] [Table 2]

[0170] [Table 3]

[0171] The results of the above-mentioned Examples and Comparative Examples will be compared and explained.

[0172] In Examples 1 to 7, the PPS resin compositions contain (a) polyphenylene sulfide resin and (b) silicone-based polymer compound in a specific composition, with the number-average dispersed particle size of component (b) being 3.0 μm or less. This results in both excellent flexibility and flame retardancy, as well as excellent toughness, as exemplified by tensile elongation at break. Among Examples 1 to 3, the smaller the number-average dispersed particle size of component (b), the better the toughness. Furthermore, comparing Examples 3 and 4 with 5 and 6, it can be seen that the use of a (b) silicone-based polymer compound with a small average primary particle size reduces the number-average dispersed particle size of component (b), resulting in better toughness and flame retardancy. Example 7, which uses a different kneading method, exhibits inferior dispersibility of the silicone-based polymer compound and inferior flame retardancy and tensile elongation at break compared to Example 1.

[0173] Comparative Examples 1 and 2, which are made of PPS resin alone, and Comparative Example 3, which contains a small amount of silicone polymer compound, have excellent flame retardancy, but have high rigidity and low tensile elongation at break, making them difficult to apply to components that require toughness.

[0174] Comparative Examples 4 to 6 and 11 contain a silicone polymer compound and achieve excellent flexibility and flame retardancy, but have low tensile elongation at break. This is presumably due to the fact that the melt viscosity of the PPS resin composition is insufficient, resulting in a coarse number average dispersed particle diameter of the silicone polymer compound. Comparative Example 7, which contains glass fiber, tends to have a smaller number average dispersed particle diameter than Comparative Example 5, but the inclusion of glass fiber not only significantly increases the flexural modulus, but also reduces flame retardancy.

[0175] Examples 1 and 18 show that excellent toughness and flexibility can be achieved by further blending an olefin-based elastomer. Examples 8 to 10, 15, and 16 show that the higher the non-Newtonian index of the PPS resin and the smaller the number-average dispersed particle size of the silicone-based polymer compound, the greater the improvement in toughness and flame retardancy. Comparing Examples 12 and 13, it is clear that using a (b) silicone-based polymer compound with a small average primary particle size reduces the number-average dispersed particle size of component (b), resulting in better toughness and flame retardancy. Example 11, which uses a different kneading method, exhibits inferior dispersibility of the silicone-based polymer compound and is inferior in flame retardancy and tensile elongation at break compared to Example 9.

[0176] Comparative Examples 9 and 10, which contain an olefin-based elastomer, are excellent in flexibility and tensile elongation at break, but tend to have reduced flame retardancy due to the olefin-based elastomer.

[0177] Comparative Example 13, which had the same composition as Example 1 (Sample No. 4) described in Publicly Known Document 4, exhibited flexibility and high tensile elongation at break, but had low flame retardancy, and did not provide a PPS resin composition having the flexibility, flame retardancy, and toughness that the present invention aims to provide.

[0178] From the above, it is clear that a PPS resin composition having flexibility, flame retardancy, and toughness can be obtained only by satisfying the constituent elements of the present invention.

Claims

1. A polyphenylene sulfide resin composition comprising (a) a polyphenylene sulfide resin (hereinafter referred to as "component (a)") and (b) a silicone-based polymer compound (hereinafter referred to as "component (b)"), wherein component (b) is selected from a silicone gum, a silicone elastomer, a silicone resin, and a composite containing an organopolysiloxane, and the content of component (b) relative to 100 parts by weight of component (a) is 3 parts by weight or more and 40 parts by weight or less, and the morphology (phase structure) of the polyphenylene sulfide resin composition has a phase separation structure in which component (a) forms a continuous phase and component (b) forms a dispersed phase in which the number average dispersed particle size is 3.0 μm or less, and the polyphenylene sulfide resin composition is injection molded at a cylinder temperature of 310°C and a mold temperature of 145°C to obtain a test piece having an ISO 9001 (ISO 9001) of 100%. 178 (2010) in bending tests, and has a flexural modulus of 3.0 GPa or less, and a flame retardancy of V-0 as measured on a test piece having a thickness of 1.6 mm or less in measurements according to the UL94 standard.

2. 2. The polyphenylene sulfide resin composition according to claim 1, wherein (c) an olefin-based elastomer is blended in an amount of 1 part by weight or more and 40 parts by weight or less per 100 parts by weight of the component (a).

3. 3. The polyphenylene sulfide resin composition according to claim 1, wherein the flame retardancy of the polyphenylene sulfide resin composition is V-0 when measured in accordance with the UL94 standard using a test piece having a thickness of 1.0 mm or less.

4. The polyphenylene sulfide resin composition according to any one of claims 1 to 3, wherein the polyphenylene sulfide resin composition has a tensile elongation at break of 10% or more in a tensile test in accordance with ISO 527-1, 2 (2012).

5. 5. The polyphenylene sulfide resin composition according to claim 1, wherein the morphology (phase structure) of the polyphenylene sulfide resin composition has a phase-separated structure in which the component (a) forms a continuous phase, and the component (b) forms a dispersed phase in which the component (b) is dispersed with a number average dispersed particle size of 1.0 μm or less.

6. The polyphenylene sulfide resin composition according to any one of claims 1 to 5, wherein the component (a) is a polyphenylene sulfide resin composition that is obtained by measuring the composition at a shear rate of 60 to 6080 s using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10. －１ The polyphenylene sulfide resin composition has a non-Newtonian index N of 1.30 or more, calculated by the following formula (1), when a shear stress is measured at 1000 kJ / cm2 at 1000 kJ / cm2. SR=K・SS Ｎ ・・・(1) (where N is the non-Newtonian index, SR is the shear rate (1 / sec), and SS is the shear stress (dyne / cm ２ ), and K is a constant.

7. The polyphenylene sulfide resin composition according to any one of claims 1 to 6, wherein the polyphenylene sulfide resin composition has a shear rate of 122 s when measured using a capillograph under the conditions of 300°C, orifice length L (mm) / orifice diameter D (mm) = 10. －１ A polyphenylene sulfide resin composition having a melt viscosity of 400 Pa·s or more.

8. 8. The polyphenylene sulfide resin composition according to claim 1, wherein the component (b) is a silicone-based core-shell rubber.

9. A molded article made of the polyphenylene sulfide resin composition according to any one of claims 1 to 8.

10. A molded article for piping having a hollow shape, which is made of the polyphenylene sulfide resin composition according to claim 9.

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