Polyphenylene sulfide resin composition and method for producing same

Abstract

A polyphenylene sulfide resin composition obtained by blending 3-25 parts by weight of (B) an olefin-based elastomer resin per 100 parts by weight of (A) a polyphenylene sulfide resin having a melt viscosity exceeding 200 Pa∙s at a temperature of 310°C, a shear speed of 1216 / s, and an L / D of 10, where L / D is the ratio of the orifice length L and the orifice diameter D, wherein the polyphenylene sulfide resin composition has a melt viscosity of 120-200 Pa∙s at a temperature of 320°C, a shear speed of 4700 / s, and an L / D of 40, where L / D is the ratio of the orifice length L and the orifice diameter D, and moreover has a weight loss on heating of 0.8 wt% or less when heated for two hours at 320°C in an air atmosphere. Provided is a polyphenylene sulfide resin composition having exceptional impact resistance, low burr properties, and low gas properties.

Description

[Technical Field]

[0001] The present invention relates to a polyphenylene sulfide resin composition. [Background technology]

[0002] Polyphenylene sulfide resin (hereinafter sometimes abbreviated as PPS resin) has properties that make it suitable as an engineering plastic, such as excellent heat resistance, chemical resistance, electrical insulation, and resistance to moist heat, and is used in a variety of electrical and electronic components, machine parts, and automotive parts through injection molding and extrusion molding.

[0003] However, PPS resin has lower impact resistance than other engineering plastics such as nylon and polybutylene terephthalate, so for applications requiring impact resistance, methods of blending PPS resin with olefin-based resins have long been considered.

[0004] For example, Patent Document 1 discloses a method of blending an ethylene-α-olefin copolymer, which has excellent impact resistance, with a polyphenylene sulfide resin. However, because the solidification temperature of the ethylene-α-olefin copolymer is lower than that of PPS, there is a problem in that flash tends to occur during molding.

[0005] As a method for suppressing the generation of burrs during molding, Patent Document 2 discloses a PPS resin composition in which an alkoxysilane compound is blended with a polyphenylene sulfide resin to reduce burrs during injection molding. Patent Document 3 discloses a method in which a polyphenylene sulfide resin and an alkoxysilane compound are continuously fed independently to an extruder. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-198923 [Patent Document 2] Japanese Patent Application Publication No. 11-158280 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-24740 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the method described in Patent Document 2, when blending an alkoxysilane compound with a PPS resin, the reaction between the PPS resin and the alkoxysilane compound is insufficient during melt-kneading in an extruder, requiring the addition of a relatively large amount of the alkoxysilane compound. As a result, during molding of the PPS resin, gas derived from the alkoxysilane compound forms mold deposits (deposits that adhere to the mold surface), resulting in poor surface appearance of the molded product, reduced dimensional accuracy of the molded product, and reduced productivity due to the need to disassemble and clean the mold. Furthermore, in the method described in Patent Document 3, the ignition point of the alkoxysilane compound is lower than the temperature at which the polyphenylene sulfide resin is melt-kneaded, raising concerns about ignition if the alkoxysilane compound is directly added as a liquid.

[0008] An object of the present invention is to obtain a polyphenylene sulfide resin composition that has excellent impact resistance and generates little flash and gas during molding without significantly impairing the inherent properties of polyphenylene sulfide resin. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention.

[0010] That is, the present invention provides the following. (1) A polyphenylene sulfide resin composition obtained by blending 100 parts by weight of (A) a polyphenylene sulfide resin having a melt viscosity of more than 200 Pa·s at a temperature of 310°C, an orifice length L to orifice diameter D ratio of 10, and a shear rate of 1216 / s, with 3 to 25 parts by weight of (B) an olefin-based elastomer resin, wherein the polyphenylene sulfide resin composition has a melt viscosity of 120 Pa·s or more and 200 Pa·s or less at a temperature of 320°C, an orifice length L to orifice diameter D ratio of 40, and a shear rate of 4700 / s, and exhibits a heat loss of 0.8% or less when heated in an air atmosphere at 320°C for 2 hours. (2) The polyphenylene sulfide resin composition according to (1), wherein the polyphenylene sulfide resin (A) contains (A1) a polyphenylene sulfide resin having an ash content of 0.10% by weight or less and (A2) a polyphenylene sulfide resin having an ash content of 0.20% by weight or more. (3) The polyphenylene sulfide resin composition according to any one of (1) to (2), wherein the polyphenylene sulfide resin (A) has a branched structure and / or a crosslinked structure derived from a polyhalogenated aromatic compound having three or more halogen substituents per molecule. (4) The polyphenylene sulfide resin composition according to any one of (1) to (3), further comprising 0.05 to 3.0 parts by weight of (C) an alkoxysilane compound having an amino group, per 100 parts by weight of the polyphenylene sulfide resin (A). (5) A method for producing the polyphenylene sulfide resin composition according to (4) above, comprising the steps of: premixing 1 to 25 parts by weight of 100 parts by weight of the (A) polyphenylene sulfide resin with 0.05 to 3.0 parts by weight of an alkoxysilane compound having an amino group (C) to prepare a (D) alkoxysilane compound premix; and separately feeding the (D) alkoxysilane compound premix and the remaining 99 to 75 parts by weight of the (A) polyphenylene sulfide resin to an extruder. (6) The method for producing a polyphenylene sulfide resin composition according to (5) above, wherein the moisture content of the polyphenylene sulfide resin (A) to be fed to the extruder is 1% by weight or less. [Effects of the Invention]

[0011] According to the present invention, by blending an olefin-based elastomer resin with a PPS resin in a specific ratio and controlling the melt viscosity and heat loss of the PPS resin composition, it is possible to provide a PPS resin composition that maintains high impact resistance while also exhibiting excellent low flash properties (low flash generation) and low gassing properties (low mold deposits) during molding.

[0012] The polyphenylene sulfide resin composition of the present invention has excellent impact resistance, low flash properties, and low gas production, and is therefore useful for a variety of applications, such as electrical and electronic equipment, precision machinery equipment, office equipment, automotive and vehicle parts, building materials, packaging materials, furniture, and daily necessities. [Brief explanation of the drawings]

[0013] [Figure 1] (a) Top view of molded product for mold deposit evaluation, (b) side view of the molded product in (a). DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail.

[0015] The polyphenylene sulfide resin (A) used in the present invention is a polymer having a repeating unit represented by the following structural formula (I).

[0016] [ka]

[0017] From the viewpoint of heat resistance, a polymer containing 70 mol % or more, and even more preferably 90 mol % or more, of repeating units represented by the above structural formula is preferable. Furthermore, 30 mol % or less of the repeating units of the PPS resin may be composed of repeating units having any of the following structures.

[0018] [ka]

[0019] The method for producing the PPS resin used in the present invention is described below. The PPS resin can be obtained using the raw materials shown below, through a pre-process, polymerization reaction process, and recovery process, which will be described later.

[0020] First, the polyhalogenated aromatic compound, sulfidizing agent, polymerization solvent, molecular weight regulator, polymerization aid and polymerization stabilizer used will be described.

[0021] [Polyhalogenated aromatic compounds] Polyhalogenated aromatic compounds are compounds having two or more halogen atoms in one molecule. Specific examples include dihalogenated benzenes such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, and 1-methoxy-2,5-dichlorobenzene; 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, and hexachlorobenzene.

[0022] Preferably, a p-dihalogenated aromatic compound is used. Although it is also possible to combine two or more different polyhalogenated aromatic compounds to form a copolymer, it is preferable to use 70 mol% or more, and even 90 mol% or more, of a p-dihalogenated aromatic compound. As the p-dihalogenated aromatic compound, p-dichlorobenzene is preferably used.

[0023] The amount of the 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 the sulfidizing agent, in order to obtain a PPS resin with a viscosity suitable for processing.

[0024] From the viewpoint of burr reduction, it is preferable to use a polyhalogenated aromatic compound having three or more halogen substituents per molecule as a raw material for PPS resin. When producing PPS resin, using a polyhalogenated aromatic compound having three or more halogen substituents per molecule as the polyhalogenated aromatic compound is preferable because it allows the introduction of a branched structure and / or crosslinked structure derived from the compound. That is, the polyphenylene sulfide resin (A) used in the present invention preferably has a branched structure and / or crosslinked structure derived from a polyhalogenated aromatic compound having three or more halogen substituents per molecule. A branched structure is a structure in which another polymer chain is generated from the middle of a polymer chain, and a crosslinked structure is a three-dimensional structure in which multiple polymer chains are bridged. As a polyhalogenated aromatic compound having three or more halogen substituents per molecule, a polyhalogenated benzene having three or more halogen substituents per molecule is preferable. Specific examples of polyhalogenated benzenes having three or more halogen substituents per molecule include 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, and hexachlorobenzene. Preferably, 1,3,5-trichlorobenzene is used.

[0025] The amount of the polyhalogenated aromatic compound having three or more halogen substituents per molecule used is, for example, in the range of 0.0001 to 0.01 mole, preferably 0.0002 to 0.005 mole, per mole of the sulfidizing agent.

[0026] [Sulfidizing agent] The sulfidizing agent includes alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

[0027] 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. Among these, sodium sulfide is preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrous forms.

[0028] 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. Among these, sodium hydrosulfide is preferred. These alkali metal hydrosulfides can be used as hydrates, aqueous mixtures, or anhydrous forms.

[0029] Alternatively, a sulfidizing agent prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can be used. Alternatively, a sulfidizing agent can be prepared from an alkali metal hydrosulfide and an alkali metal hydroxide and then transferred to a polymerization vessel for use.

[0030] Alternatively, a sulfidizing agent 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.Furthermore, a sulfidizing agent 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.

[0031] 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 sulfidizing agent used means the remaining amount obtained by subtracting the lost amount from the actual charged amount.

[0032] It is also possible to use an alkali metal hydroxide and / or an 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. Among these, sodium hydroxide is preferably used.

[0033] When an alkali metal hydrosulfide is used as the sulfidizing agent, it is particularly preferred to use an alkali metal hydroxide simultaneously. The amount of the alkali metal hydroxide 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.

[0034] [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, as well as 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 preferred.

[0035] 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.

[0036] [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 as a molecular weight regulator to form terminals in the resulting PPS resin or to regulate the polymerization reaction or molecular weight.

[0037] [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. Specific examples of such polymerization aids include carboxylates, water, alkali metal chlorides, 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. Of these, alkali metal carboxylates and / or water are preferred.

[0038] The alkali metal carboxylate is represented by the general formula R(COOM) n (wherein R is an alkyl group, cycloalkyl group, aryl group, alkylaryl group, or arylalkyl group having 1 to 20 carbon atoms; 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, anhydrous form, or 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.

[0039] 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 have high solubility in the reaction system and have a significant auxiliary effect, but are expensive, while potassium, rubidium, and cesium salts have low solubility in the reaction system. Therefore, sodium acetate, which is inexpensive and has moderate solubility in the polymerization system, is most preferably used.

[0040] When using these polymerization aids, the amount used is preferably in the range of 0.01 mol to 0.7 mol per mol of the sulfidizing agent, more preferably in the range of 0.1 mol to 0.6 mol in order to obtain a higher degree of polymerization, and even more preferably in the range of 0.2 mol to 0.5 mol.

[0041] The use of water as a polymerization aid is an effective means for obtaining a resin composition with a high balance between fluidity and high impact resistance. In this case, the amount of water added is preferably in the range of 0.5 mol to 15 mol per mol of the sulfidizing agent, more preferably in the range of 0.6 mol to 10 mol, and even more preferably in the range of 1 mol to 5 mol, in order to obtain a higher degree of polymerization.

[0042] There is no particular restriction on the timing of addition of these polymerization aids, and they may be added at any time during the pre-step described below, at the start of polymerization, or during polymerization. They may also be added in multiple batches. When an alkali metal carboxylate is used as the polymerization aid, it is preferable to add it simultaneously at the start of the pre-step or at the start of polymerization, as this facilitates addition. When water is used as the polymerization aid, it is effective to add it during the polymerization reaction after charging the polyhalogenated aromatic compound.

[0043] [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 formation of thiophenol. The addition of a polymerization stabilizer can suppress the formation of thiophenol. 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 and are therefore included in the polymerization stabilizers used in the present invention. Furthermore, as mentioned above, 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 serve as a polymerization stabilizer.

[0044] These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is used in a ratio of preferably 0.02 mol to 0.2 mol, more preferably 0.03 mol to 0.1 mol, and even more preferably 0.04 mol to 0.09 mol per mol of the sulfidizing agent. If this ratio is too low, the stabilizing effect will be insufficient, and conversely, if it is too high, it will be economically disadvantageous and the polymer yield will tend to decrease.

[0045] The timing of adding the polymerization stabilizer is not particularly specified, and it may be added at any time during the pre-processing step described below, at the start of polymerization, or during polymerization. It may also be added in multiple batches. It is more preferable to add it at the start of the pre-processing step or at the start of polymerization.

[0046] Next, the pre-process, the polymerization reaction process, and the recovery process will be specifically explained in order.

[0047] [Pre-process] In the polymerization of PPS resin, the sulfidizing agent is usually used in the form of a hydrate. Before adding the polyhalogenated aromatic compound, it is preferable to heat the mixture containing the organic polar solvent and the sulfidizing agent and remove excess water from the system. This step is called the pre-step. If too much water is removed during this process, it is preferable to add water to make up for the shortage.

[0048] As mentioned above, the sulfidizing agent can also be an alkali metal sulfide prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide, or in a separate vessel from the polymerization vessel. 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 in 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°C to 245°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.

[0049] In the polymerization reaction, the amount of water in the polymerization system is preferably 0.5 to 10.0 moles per mole of the sulfidizing agent. Here, the amount of water in the polymerization system is the amount of water charged into 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 crystal water.

[0050] [Polymerization reaction process] After the pre-processing step, the PPS resin is preferably produced by reacting the sulfidizing agent with the polyhalogenated aromatic compound in an organic polar solvent at a temperature ranging from 200° C. to less than 290° C. This step is called the polymerization reaction step.

[0051] To start the polymerization reaction, the sulfidizing agent and the polyhalogenated aromatic compound are added to an organic polar solvent, preferably in an inert gas atmosphere, at a temperature ranging from room temperature to 215°C, and preferably from 100°C to 215°C. A polymerization aid may also be added at this stage. These raw materials may be added in any order, or simultaneously.

[0052] The mixture is usually heated to a temperature in the range of 200° C. to 290° C. There are no particular restrictions on the temperature-raising rate, but the range of 0.01° C. / min to 5° C. / min is preferably selected, and the range of 0.1° C. / min to 3° C. / min is more preferable.

[0053] In general, the temperature is finally raised to 250° C. to 290° C., and the reaction is carried out at that temperature for preferably 0.25 to 50 hours, more preferably 0.5 to 20 hours.

[0054] A method of reacting at a temperature of 200°C to 245°C for a certain period of time before reaching the final temperature, and then raising the temperature to 270°C to 290°C, is effective in obtaining a higher degree of polymerization. In this case, the reaction time at a temperature of 200°C to 245°C is preferably selected from the range of 0.25 to 20 hours, more preferably from the range of 0.25 to 10 hours. In order to obtain a polymer with a higher degree of polymerization, it is effective to start the reaction when the conversion of the polyhalogenated aromatic compound in the system at 245°C reaches preferably 40 mol% or more, more preferably 60 mol% or more.

[0055] [Recovery process] After the polymerization reaction step is completed, solid matter is recovered from the polymerization reaction product containing the polymer, solvent, etc. This step is called the recovery step. Any known recovery method may be used.

[0056] For example, after the polymerization reaction is completed, the polymerization reaction product may be slowly cooled to recover the particulate polymer. The cooling rate is not particularly limited, but is typically about 0.1°C / min to 3°C / min. It is not necessary to cool at the same rate throughout the entire slow cooling process; instead, the polymer may be cooled at a rate of 0.1°C / min to 1°C / min until the polymer particles crystallize and precipitate, and then cooled at a rate of 1°C / min or faster.

[0057] Another preferred method is to carry out the recovery under rapid cooling conditions. One preferred recovery method is the flash method. In the flash method, the polymerization reaction product is subjected to high temperature and high pressure (usually 250°C or higher, 8 kg / cm 2 This method involves flashing the polymer from the above-mentioned state into an atmosphere under normal pressure or reduced pressure, recovering the solvent and simultaneously recovering the polymer in powder form. The term "flashing" used here means ejecting the polymerization product from a nozzle. Specific examples of the flashing atmosphere include nitrogen or water vapor at normal pressure, and the temperature is usually selected within the range of 150°C to 250°C.

[0058] The flash method is an economical recovery method because it allows the recovery of solids simultaneously with the recovery of solvents and the recovery time can be relatively short. In this recovery method, ionic compounds such as sodium and organic low-polymerization substances (oligomers) tend to be easily incorporated into the polymer during the solidification process.

[0059] [Post-processing process] In the present invention, a post-treatment step may be added to the PPS resin produced through the pre-processing, polymerization reaction step, and recovery step described above. Examples of post-treatment include acid treatment, hot water treatment, washing with an organic solvent, alkali metal treatment, and alkaline earth metal treatment.

[0060] 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, as long as it does not have the effect of decomposing the PPS resin, and examples 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. On the other hand, acids such as nitric acid that decompose and deteriorate the PPS resin are not preferred.

[0061] The acid treatment can be carried out, for example, 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 acetic acid at pH 4 heated to 80°C to 200°C and stirring for 30 minutes. The pH of the aqueous solution after treatment may be 4 or higher, for example, about pH 4 to 8. In order to remove residual acid or salt from the acid-treated PPS resin, it is preferable to wash the resin several times with water or warm water. 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.

[0062] 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.

[0063] To achieve the desired chemical modification effect of the PPS resin by hot water treatment, 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 (weight of cleaning solution relative to dry PPS weight) of 200 g or less of PPS resin per liter of water is usually selected.

[0064] 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, in order to remove any remaining components, it is preferable to wash the PPS resin after this hot water treatment operation several times with warm water.

[0065] Washing with an organic solvent is as follows: There are no particular restrictions on the organic solvent used to wash the PPS resin, as long as it does not have the effect of decomposing the PPS resin. Examples of organic solvents that can be used to clean PPS resin 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 a solvent selected from N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform, etc. These organic solvents may be used alone or in combination of two or more.

[0066] Washing with an organic solvent can be performed, for example, by immersing the PPS resin in the organic solvent, with stirring or heating as necessary. There are no particular limitations on the washing temperature when washing the PPS resin with an organic solvent, and any temperature between room temperature and approximately 300°C can be selected. While higher washing temperatures tend to improve washing 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 limitations on the washing time. While this depends on the washing conditions, a batch-type washing period of 5 minutes or longer usually produces a sufficient effect. Continuous washing is also possible. The post-treatment step preferably involves acid treatment, hot water treatment, or washing with an organic solvent, and a combination of two or more treatments is preferred from the perspective of impurity removal.

[0067] Examples of methods for alkali metal or alkaline earth metal treatment include adding an alkali metal salt or alkaline earth metal salt after removing residual oligomers and residual salts by washing with an organic solvent or by washing with warm or hot water. A preferred method for adding an alkali metal or alkaline earth metal salt is washing the PPS resin in an aqueous solution containing the alkali metal salt or alkaline earth metal salt. By carrying out such alkali metal or alkaline earth metal treatment, a PPS resin containing an alkali metal or alkaline earth metal can be obtained.

[0068] The alkali metal or alkaline earth metal is preferably introduced into the PPS resin in the form of an acetate, hydroxide, carbonate, etc. Excess alkali metal salt or alkaline earth metal salt is preferably removed by washing with hot water, etc.

[0069] The alkali metal ion concentration or alkaline earth metal ion concentration when introducing the alkali metal or alkaline earth metal is preferably 0.001 mmol or more per 1 g of PPS resin. The treatment 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 temperature limit, but from the viewpoint of operability, 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.

[0070] In order to obtain a PPS resin composition having excellent moldability and heat resistance, the post-treatment step preferably involves removing residual oligomers and salts by repeating several times washing with an organic solvent and warm water at about 80°C or the above-mentioned hot water treatment, followed by treatment with an acid or an alkali metal salt or alkaline earth metal salt, and particularly preferably treatment with an alkali metal salt or alkaline earth metal salt.

[0071] The PPS resin used in the present invention may be further subjected to a thermal oxidation treatment after the above-mentioned post-treatment. The thermal oxidation treatment involves heating the PPS resin in an oxygen atmosphere or by heating with the addition of a peroxide such as H2O2 or a vulcanizing agent such as sulfur. Heating in an oxygen atmosphere is particularly preferred due to the simplicity of the treatment.

[0072] The heating device for the thermal oxidation treatment of the present invention may be a conventional hot air dryer or a rotary or impeller-equipped heating device. However, for efficient and more uniform treatment, a rotary or impeller-equipped heating device is preferred. The oxygen concentration in the atmosphere during the thermal oxidation treatment is preferably 2% by volume or higher. There is no particular upper limit on the oxygen concentration, but for safe operation, the limit is approximately 50% by volume, and 25% by volume or less is more preferred. The thermal oxidation treatment temperature of the present invention is preferably 160°C to 270°C, more preferably 160°C to 220°C. Thermal oxidation treatment at temperatures above 270°C is undesirable because the thermal oxidation treatment progresses too rapidly, making it difficult to control and significantly reducing fluidity. On the other hand, temperatures below 160°C are undesirable because the thermal oxidation treatment progresses significantly slower and generates a large amount of volatile components. The treatment time may be 0.2 to 50 hours, more preferably 0.5 to 10 hours, and even more preferably 1 to 5 hours. If the treatment time is less than 0.2 hours, the thermal oxidation treatment cannot be carried out sufficiently and there will be a large amount of volatile components, which is undesirable, and if the treatment time exceeds 50 hours, the crosslinking reaction due to the thermal oxidation treatment will proceed, resulting in a decrease in fluidity.

[0073] The PPS resin used in the present invention must have a melt viscosity of more than 200 Pa·s at a temperature of 310°C, an L / D ratio (where L is the ratio of the orifice length L to the orifice diameter D) of 10, and a shear rate of 1216 / s. A melt viscosity of 200 Pa·s or less is undesirable because it results in insufficient flash reduction. The lower limit of the melt viscosity is preferably 300 Pa·s or more, more preferably 400 Pa·s or more, and even more preferably 700 Pa·s or more. There are no particular upper limits to the melt viscosity, but from the viewpoint of poor flowability during molding, it is preferably 1000 Pa·s or less, more preferably 900 Pa·s or less, and even more preferably 800 Pa·s or less.

[0074] When the PPS resin of the present invention contains two or more types of PPS resins, the mixture of these PPS resins must satisfy the above-mentioned melt viscosity range.

[0075] The melt viscosity of the PPS resin was measured using a capillary rheometer (Capillograph (registered trademark) 1D manufactured by Toyo Seiki Seisakusho Co., Ltd.) and a capillary with an orifice length of 10 mm and an orifice diameter of 1 mm (L / D = 10) at a temperature of 310°C and a shear rate of 1216 / s.

[0076] The method for obtaining a PPS resin having such a melt viscosity is not particularly limited, but examples thereof include a method in which the weight average molecular weight (Mw) is adjusted in the polymerization reaction step or the thermal oxidation treatment step.

[0077] From the viewpoint of a balance between moldability and flash reduction, the PPS resin used in the present invention preferably contains (A1) a PPS resin having an ash content of 0.10% by weight or less and (A2) a PPS resin having an ash content of 0.20% by weight or more. A higher ash content means a higher metal content in the PPS resin. If the metal content is too low, excessive reaction with (B) the olefinic elastomer resin tends to reduce moldability and mold fouling due to increased gas generation. If the metal content is high, reactivity with (B) the olefinic elastomer resin tends to decrease, resulting in reduced impact resistance and flash reduction. From the viewpoint of a balance between moldability, flash reduction, and low gas reduction, it is preferable to use a combination of (A1) a PPS resin having an ash content of 0.10% by weight or less and (A2) a PPS resin having an ash content of 0.20% by weight or more. The lower limit of the ash content of (A1) the PPS resin having an ash content of 0.10% by weight or less is preferably 0.00% by weight. The upper limit of the ash content is more preferably 0.09% by weight or less, and even more preferably 0.08% by weight or less. (A2) For PPS resins with an ash content of 0.20% by weight or more, the lower limit of the ash content is more preferably 0.21% by weight or more, and even more preferably 0.22% by weight or more. The upper limit of the ash content is more preferably 0.35% by weight or less, and even more preferably 0.30% by weight or less.

[0078] The ratio of (A1) PPS resin with an ash content of 0.10 wt% or less to (A2) PPS resin with an ash content of 0.20 wt% or more is not particularly limited, but from the viewpoint of a balance between moldability, low flash, and low gas production, a weight ratio of (A1) / (A2) of 5 / 95 to 95 / 5 is preferred. The lower limit of the ratio of (A1) PPS resin with an ash content of 0.10 wt% or less, based on a total of (A1) PPS resin with an ash content of 0.10 wt% or less and (A2) PPS resin with an ash content of 0.20 wt% or more, is preferably 10 wt% or more, more preferably 30 wt% or more, even more preferably 40 wt% or more, and most preferably 50 wt% or more. The upper limit of the ratio of (A1) PPS resin with an ash content of 0.10 wt% or less, is not particularly limited, but is preferably 90 wt% or less, more preferably 80 wt% or less, and most preferably 70 wt% or less.

[0079] There are no particular limitations on the method for reducing the ash content of the PPS resin used in the present invention to 0.10 wt% or less. An example of such a method is washing the PPS resin powder after polymerization by immersing it in an aqueous acetic acid solution of pH 4 heated to 80°C to 200°C and stirring for 30 minutes. There are also no particular limitations on the method for reducing the ash content of the PPS resin to 0.20 wt% or more. Examples 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. The easiest method is adding an alkali metal salt or alkaline earth metal salt after removing residual oligomers and salts by organic solvent washing or warm or hot water washing. The alkali metal or alkaline earth metal is preferably introduced into the PPS in the form of an acetate, hydroxide, carbonate, or the like.

[0080] The polyphenylene sulfide resin composition of the present invention contains (B) an olefinic elastomer resin. Examples of (B) an olefinic elastomer resin include homopolymers of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-octene, 4-methyl-1-pentene, and isobutylene, and (co)polymers obtained by polymerizing two or more of these; and copolymers of α-olefins with α,β-unsaturated acids and alkyl esters thereof such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Specific examples include ethylene / propylene copolymer (" / " indicates copolymerization, the same applies below), ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, etc.

[0081] The olefin elastomer resin (B) used in the present invention is preferably an α-olefin copolymer having an epoxy group.

[0082] Epoxy group-containing α-olefin copolymers can be obtained by introducing a functional group-containing component, such as a glycidyl ester of an α,β-unsaturated acid, into an olefin elastomer. Examples of α,β-unsaturated acid glycidyl esters include epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate. There are no particular limitations on the method for introducing these functional group-containing components; for example, they can be copolymerized during copolymerization of an olefin (co)polymer, or introduced by graft polymerization using a radical initiator onto an olefin (co)polymer.

[0083] The amount of the functional group-containing component introduced is preferably within the range of 0.001 mol % to 40 mol %, more preferably 0.01 mol % to 35 mol %, based on all monomers constituting the α-olefin copolymer having an epoxy group.

[0084] Specific examples of particularly useful α-olefin copolymers having epoxy groups include ethylene / propylene-g-glycidyl methacrylate copolymer ("g" represents graft, the same applies hereinafter), ethylene / 1-butene-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, and epoxy group-containing olefin copolymers containing, in addition to an α-olefin such as ethylene or propylene and a glycidyl ester of an α,β-unsaturated acid, other monomers as essential components.

[0085] The blending amount of the (B) olefin-based elastomer resin used in the present invention must be 3 to 25 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin. If the blending amount of the (B) olefin-based elastomer resin is less than 3 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin, impact resistance will be insufficient. If the blending amount of the (B) olefin-based elastomer resin is more than 25 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin, mechanical strength will decrease and appearance defects due to flash or gas will easily occur during molding. The lower limit of the amount of the (B) olefin-based elastomer resin is preferably 4 parts by weight or more per 100 parts by weight of the (A) polyphenylene sulfide resin, more preferably 5 parts by weight or more, and even more preferably 6 parts by weight or more. The upper limit of the amount of (B) olefinic elastomer resin is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less, per 100 parts by weight of (A) polyphenylene sulfide resin.

[0086] Furthermore, in order to obtain excellent moldability and water pressure resistance, it is preferable to use (B) an olefin elastomer resin in combination with (B-1) an α-olefin copolymer having epoxy groups and (B-2) an olefin (co)polymer having no polar functional groups. In this case, there are no particular restrictions on the amount of (B-1) an α-olefin copolymer having epoxy groups, but from the viewpoint of moldability, it is preferable that the amount be 6 parts by weight or less per 100 parts by weight of (A) polyphenylene sulfide resin.

[0087] (B-2) Examples of olefin (co)polymers without polar functional groups include homopolymers of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-octene, 4-methyl-1-pentene, and isobutylene, as well as (co)polymers obtained by polymerizing two or more of these. Specific examples include ethylene / propylene copolymers (" / " indicates copolymerization, the same applies below), ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, and ethylene / 1-octene copolymers. Ethylene / 1-butene copolymers or ethylene / 1-octene copolymers are preferred.

[0088] When (B-1) an α-olefin copolymer having epoxy groups and (B-2) an olefin (co)polymer having no polar functional groups are used in combination as the (B) olefin-based elastomer resin, there are no particular restrictions on the ratio. However, from the viewpoints of flash reduction and moldability, a weight ratio of (B-1) / (B-2) of 5 / 95 to 95 / 5 is preferred. The lower limit of the ratio of (B-1) an α-olefin copolymer having epoxy groups, based on 100% by weight of the total of (B-1) an α-olefin copolymer having epoxy groups and (B-2) an olefin (co)polymer having no polar functional groups, is preferably 10% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, and most preferably 70% by weight or more. The upper limit of the ratio of (B-1) an α-olefin copolymer having epoxy groups is preferably 90% by weight or less, more preferably 85% by weight or less, and even more preferably 80% by weight or less.

[0089] The polyphenylene sulfide resin composition of the present invention preferably further contains (C) an alkoxysilane compound having an amino group. Examples of (C) an alkoxysilane compound having an amino group include γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Among these, γ-aminopropyltriethoxysilane is particularly suitable for achieving excellent burr reduction effects.

[0090] The amount of the (C) alkoxysilane compound having an amino group is preferably 0.05 to 3.0 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin. When the amount of the (C) alkoxysilane compound having an amino group is 0.05 parts by weight or more per 100 parts by weight of the (A) polyphenylene sulfide resin, a burr reduction effect is obtained, which is preferable. When the amount of the (C) alkoxysilane compound having an amino group is 3.0 parts by weight or less per 100 parts by weight of the (A) polyphenylene sulfide resin, good molding processability is obtained, which is preferable. The lower limit of the amount of the (C) alkoxysilane compound having an amino group is preferably 0.10 parts by weight or more per 100 parts by weight of the (A) polyphenylene sulfide resin, more preferably 0.20 parts by weight or more, and even more preferably 0.30 parts by weight or more. The upper limit of the amount of the amino group-containing alkoxysilane compound (C) is preferably 2.0 parts by weight or less, more preferably 1.5 parts by weight or less, and even more preferably 1.0 part by weight or less, per 100 parts by weight of the polyphenylene sulfide resin (A).

[0091] The polyphenylene sulfide resin composition of the present invention can also be used by blending fibrous and / or non-fibrous fillers within the range that does not impair the effects of the present invention. Specific examples of such fillers include fibrous fillers such as glass fiber, carbon fiber, carbon nanotubes, carbon nanohorns, cellulose nanofibers, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, and metal fiber; silicates such as fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, and alumina silicate; metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; sulfates such as calcium sulfate and barium sulfate; and non-fibrous fillers such as glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, silica, and graphite. These may be hollow. Furthermore, two or more of these fillers can be used in combination. These fillers may also be pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound. From the viewpoint of impact resistance, the upper limit of the amount of such fibrous and / or non-fibrous filler is preferably 15 parts by weight or less, more preferably 10 parts by weight or less, even more preferably 5 parts by weight or less, and most preferably 0 part by weight, per 100 parts by weight of the (A) polyphenylene sulfide resin. If the amount of fibrous and / or non-fibrous filler exceeds 15 parts by weight per 100 parts by weight of the (A) polyphenylene sulfide resin, impact resistance decreases, which is undesirable.

[0092] To maintain high heat resistance and thermal stability, the polyphenylene sulfide resin composition of the present invention preferably contains one or more antioxidants selected from phenolic antioxidants and phosphorus-based antioxidants, within a range that does not impair the effects of the present invention. From the viewpoint of improving heat resistance, the amount of antioxidant added is preferably 0.01 parts by weight or more, and more preferably 0.02 parts by weight or more, per 100 parts by weight of the polyphenylene sulfide resin (A). From the viewpoint of gas components generated during molding, the amount is preferably 5 parts by weight or less, and more preferably 1 part by weight or less, per 100 parts by weight of the polyphenylene sulfide resin. Furthermore, using a phenolic antioxidant and a phosphorus-based antioxidant in combination is particularly effective in maintaining heat resistance and thermal stability, and is therefore preferred.

[0093] The polyphenylene sulfide resin composition of the present invention may be blended with resins other than the components (A) and (B) as long as the effects of the present invention are not impaired. While there are no particular limitations on the resins that can be blended, specific examples include polyamide resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexyldimethylene terephthalate, and polynaphthalene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyetherester elastomers, polyetheramide elastomers, polyamideimides, polyacetals, polyimides, polyetherimides, siloxane copolymerized polyimides, polyethersulfones, polysulfone resins, polyarylsulfone resins, polyketone resins, polyarylate resins, liquid crystal polymers, polyetherketone resins, polythioetherketone resins, polyetheretherketone resins, polyamideimide resins, and tetrafluoroethylene resins.

[0094] The polyphenylene sulfide resin composition of the present invention may contain other components within the range that does not impair the effects of the present invention, such as antioxidants and heat stabilizers (hydroquinone-based) other than those mentioned above, weathering agents (resorcinol-based, salicylate-based, benzotriazole-based, benzophenone-based, hindered amine-based, etc.), mold release agents and lubricants (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide, bisurea, polyethylene wax, etc.), pigments (cadmium sulfide, phthalocyanine, coloring carbon black, etc.), dyes (nigrosine, etc.), crystal nucleating agents (talc, silica, kaolin, clay, etc.), plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agents (alkyl sulfate-type anionic antistatic agents, quaternary ammonium salt-type cationic antistatic agents, etc.), and nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine-based amphoteric antistatic agents, etc.), flame retardants (for example, red phosphorus, phosphate esters, melamine cyanurate, hydroxides such as magnesium hydroxide and aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resins, or combinations of these brominated flame retardants with antimony trioxide, etc.), heat stabilizers, lubricants such as calcium stearate, aluminum stearate, and lithium stearate, strength improvers such as bisphenol epoxy resins such as bisphenol A, novolac phenol epoxy resins, and cresol novolac epoxy resins, ultraviolet inhibitors, colorants, flame retardants, and foaming agents.

[0095] The polyphenylene sulfide resin composition of the present invention was subjected to a shear rate of 4700 s at a temperature of 320°C, a ratio of the orifice length L to the orifice diameter D of L / D of 40, and -1The melt viscosity (Pa·s) at this temperature must be 120 Pa·s or more and 200 Pa·s or less. By controlling the melt viscosity within this range, not only can an excellent flash reduction effect be obtained, but mechanical strength and impact resistance are also improved. If the melt viscosity is less than 120 Pa·s, the flash reduction effect is insufficient. If the melt viscosity exceeds 200 Pa·s, the fluidity decreases, resulting in a decrease in molding processability and a deterioration in the appearance of the molded product. The lower limit of the melt viscosity is preferably 125 Pa·s or more, more preferably 130 Pa·s or more, and even more preferably 135 Pa·s or more. The upper limit of the melt viscosity is preferably 190 Pa·s or less, more preferably 180 Pa·s or less. The melt viscosity was measured using a Yasuda Seiki capillary rheometer and a capillary with an orifice length of 40 mm and an orifice diameter of 1 mm (L / D=40) at a temperature of 320°C and a shear rate of 4700 s -1 The melt viscosity of the PPS resin composition is determined under the following conditions: (A) ...

[0096] The polyphenylene sulfide resin composition of the present invention must have a heat loss of 0.8% by weight or less when heated in an air atmosphere at 320°C for 2 hours. Controlling the heat loss within this range not only achieves excellent low-gassing effects, but also ensures good product appearance. If the heat loss exceeds 0.8% by weight, mold deposits increase, deteriorating the appearance of the molded product. The upper limit of the heat loss is preferably 0.7% by weight or less, more preferably 0.6% by weight or less. To obtain a PPS resin composition with such a heat loss, for example, the ratio of (A1) PPS resin having an ash content of 0.10% by weight or less to (A2) PPS resin having an ash content of 0.20% by weight or more, or the type and composition of (B) olefinic elastomer resin can be adjusted.

[0097] The method for producing the polyphenylene sulfide resin composition of the present invention is not particularly limited, but a representative example includes a method in which the above-mentioned raw materials are mixed and fed into a known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll, and then kneaded.

[0098] Among these, a method of melt-kneading using a twin-screw extruder having a ratio L / D of screw length L to screw diameter D of 10 or more and 100 or less is preferred. L / D is more preferably 20 or more and 100 or less, and even more preferably 30 or more and 100 or less.

[0099] The order of mixing raw materials when melt-kneading to produce the polyphenylene sulfide resin composition of the present invention is not particularly limited, and any of the following methods may be used: all raw materials are fed through the main feed port and melt-kneaded using the above method; some raw materials are melt-kneaded using the above method, and then the remaining raw materials are blended and melt-kneaded; or some raw materials are fed through the main feed port and melt-kneaded using a single-screw or twin-screw extruder, while the remaining raw materials are being mixed using a side feeder. Particularly preferred is a method in which 1 to 25 parts by weight of 100 parts by weight of the (A) polyphenylene sulfide resin and 0.05 to 3.0 parts by weight of the (C) alkoxysilane compound having an amino group are premixed (hereinafter referred to as the (D) alkoxysilane compound premix), and the (D) alkoxysilane compound premix and the remaining 99 to 75 parts by weight of the (A) polyphenylene sulfide resin are separately fed into an extruder and melt-kneaded. By mixing the raw materials in this manner, (A) the polyphenylene sulfide resin and (C) the alkoxysilane compound having an amino group can be reacted efficiently, resulting in a molded product with less flash.

[0100] There are no particular limitations on the ratio of the polyphenylene sulfide resin (A) to the alkoxysilane compound (C) having an amino group in the alkoxysilane compound (D) premix. However, since the ignition temperature of the alkoxysilane compound (C) having an amino group is lower than the melt-kneading temperature of the polyphenylene sulfide resin composition of the present invention, there is a risk of ignition when the compound is fed to the extruder. Therefore, the weight ratio of (A) / (C) is preferably in the range of 99.5 / 0.5 to 50 / 50, and more preferably in the range of 99 / 1 to 60 / 40.

[0101] The polyphenylene sulfide resin (A) in the alkoxysilane compound premix (D) may be either (A1) a PPS resin having an ash content of 0.10% by weight or less, or (A2) a PPS resin having an ash content of 0.20% by weight or more. However, from the viewpoint of obtaining a molded product with reduced flash generation by reaction with the alkoxysilane compound having an amino group (C), it is preferable to use the PPS resin (A1) having an ash content of 0.10% by weight or less.

[0102] Furthermore, the small amount of additive components can be added to the mixture before molding after kneading and pelletizing the other components by the above-mentioned method or the like.

[0103] When the polyphenylene sulfide resin composition of the present invention is produced by melt-kneading, the moisture content of the polyphenylene sulfide resin (A) supplied to the extruder is preferably 1% by weight or less. If the moisture content of the polyphenylene sulfide resin (A) supplied to the extruder exceeds 1% by weight, the reactivity with the alkoxysilane compound (C) having an amino group decreases, resulting in a decrease in the effect of reducing flash. The upper limit of the moisture content of the polyphenylene sulfide resin (A) is more preferably 0.8% by weight or less, and even more preferably 0.6% by weight or less. There are no particular limitations on the method for obtaining a PPS resin with such a moisture content, but a preferred method involves drying the polyphenylene sulfide resin (A) that has been washed and recovered after polymerization, and adjusting the drying temperature and drying time during this process.

[0104] The PPS resin composition thus obtained can be subjected to various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, and is particularly suitable for injection molding.

[0105] The polyphenylene sulfide resin composition of the present invention can be preferably used in electric and electronic devices, precision machinery devices, office equipment, automobile and vehicle parts, building materials, packaging materials, furniture, and daily necessities.

[0106] Applications of molded articles made from the PPS resin composition of the present invention include, for example, electrical and electronic components such as sensors, LED lamps, consumer connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, semiconductors, liquid crystal displays, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related components; and household and office electrical appliance components such as VTR components, television components, irons, hair dryers, rice cooker components, microwave oven components, acoustic components, audio equipment components such as audio equipment, laser discs (registered trademark), and compact discs; lighting components, refrigerator components, air conditioner components, typewriter components, and word processor components.Other products include office computer parts, telephone parts, facsimile parts, copier parts, cleaning tools, motor parts, lighters, typewriters, and other machinery-related parts; optical equipment such as microscopes, binoculars, cameras, and clocks; precision machinery-related parts; valves, alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, exhaust gas valves, and other valves; various pipes for fuel, exhaust, and intake systems; air intake nozzles, snorkels, intake manifolds, fuel pumps, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, throttle position sensors, crankshaft position sensors, and air flow meters. Examples of various applications include automobile and vehicle related parts such as motors, brake pad wear sensors, air conditioner thermostat bases, heating hot air flow control valves, brush holders for radiator motors, water pump impellers, turbine vanes, wiper motor related parts, distributors, starter switches, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, fuse connectors, horn terminals, insulating plates for electrical components, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, vehicle speed sensors, and cable liners. [Example]

[0107] The present invention will be explained in more detail below by showing examples, but the present invention is not limited to the descriptions of these examples. It should be noted that Examples 1-3 are currently reference examples, and Examples 4-13 are examples of the present invention.

[0108] (1)(A) Melt viscosity measurement of PPS resin The melt viscosity (Pa·s) was measured at a temperature of 310°C and a shear rate of 1216 / s using a Capilograph (registered trademark) 1D manufactured by Toyo Seiki Co., Ltd. and a die with an orifice length L of 10 mm and an orifice diameter D of 1 mm (L / D=10).

[0109] (2)(A) Ash content measurement of PPS resin 5.0 g of (A) PPS resin was weighed into a crucible and fired at 550°C for 6 hours using a TMF-5 electric furnace manufactured by Thomas Scientific Instruments, Inc. After firing, the crucible was removed and cooled in a desiccator containing a desiccant. The weight of the recovered residue was then weighed, and the ash content was calculated as a percentage of the weight of the residue per unit weight of (A) PPS resin before firing.

[0110] (3)(A) Moisture content measurement of PPS resin (A) 5.0 g of PPS resin was weighed into an aluminum dish and heated in an oven at 150°C for 1 hour. The aluminum dish was then removed and cooled in a desiccator containing a desiccant. The PPS resin was then weighed and the moisture content was calculated as the weight percentage of the weight loss after heating relative to the weight before heating.

[0111] (4) Melt viscosity measurement of polyphenylene sulfide resin composition The melt viscosity (Pa·s) was measured at a temperature of 320°C and a shear rate of 4700 / s using a Yasuda Seiki capillary rheometer and a die with an orifice length L of 40 mm and an orifice diameter D of 1 mm (L / D=40).

[0112] (5) Burr length Using an SE30D injection molding machine, a 40 mm diameter x 3 mm thick disk-shaped mold with eight projections on the circumference, each measuring (a) 5 mm wide x 20 mm long x 1000 μm thick, (b) 5 mm wide x 20 mm long x 700 μm thick, (c) 5 mm wide x 20 mm long x 500 μm thick, (d) 5 mm wide x 20 mm long x 300 μm thick, (e) 5 mm wide x 20 mm long x 100 μm thick, (f) 5 mm wide x 20 mm long x 50 μm thick, (g) 5 mm wide x 20 mm long x 20 μm thick, and (h) 5 mm wide x 20 mm long x 10 μm thick, was used. The PPS resin composition was injection molded at a molding temperature of 320°C, a mold temperature of 130°C, and an injection pressure of 50 MPa. The gate was located at the center of the disk. The protrusions (f) and (g) of the obtained molded product were measured for their filling length at 50x magnification using a Keyence microscope, and this was taken as the burr length. The shorter the burr length, the better the low-burr properties were judged to be.

[0113] (6) Measurement of heat loss of polyphenylene sulfide resin composition 10 g of pellets of the PPS resin composition of the present invention were weighed into an aluminum cup that had been preheated at 330°C for 3 hours, and then heated for 2 hours in a hot air dryer at 320°C. The aluminum cup was then removed, cooled in a desiccator containing a desiccant, and weighed, and the loss on heating was calculated as the weight percentage of the weight loss after heating relative to the weight before heating.

[0114] (7) Measurement of tensile strength and tensile strain Pellets of the PPS resin composition of the present invention were dried for 3 hours at 130°C using a hot air dryer, then fed into a Sumitomo Heavy Industries injection molding machine (SE-50D) set at a cylinder temperature of 320°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 central parallel section of the specimen was 400±50 mm / s to obtain test specimens. The test specimens were conditioned for 16 hours at 23°C and 50% relative humidity, and then the tensile strength and tensile strain were measured in accordance with ISO 527-1, -2 (2012) at 23°C, 50% relative humidity, a grip distance of 114 mm, and a test speed of 50 mm / s.

[0115] (8) Measurement of bending modulus Pellets of the PPS resin composition of the present invention were dried for 3 hours at 130°C using a hot air dryer, then fed into a Sumitomo Heavy Industries injection molding machine (SE-50D) set at a cylinder temperature of 320°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 central parallel section of the specimen was 400±50 mm / s to obtain a test specimen. The central parallel section of this test specimen was cut out to obtain a Type B2 test specimen. After conditioning the test specimen for 16 hours at 23°C and 50% relative humidity, the flexural modulus was measured according to ISO 178 (2010) at 23°C, 50% relative humidity, a span of 64 mm, and a test speed of 2 mm / s.

[0116] (9) Measurement of Charpy impact strength (notched) Pellets of the PPS resin composition of the present invention were dried for 3 hours at 130°C using a hot air dryer, then fed into a Sumitomo Heavy Industries injection molding machine (SE-50D) set at a cylinder temperature of 320°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 central parallel section of the specimen was 400±50 mm / s to obtain test specimens. The central parallel section of each test specimen was cut into an 80 mm length, and a V-notch was machined to obtain a 4 mm wide, notched test specimen. After conditioning the test specimens for 16 hours at 23°C and 50% relative humidity, their Charpy impact strength was measured in an atmosphere at 23°C and 50% relative humidity according to ISO 179-1 (2010).

[0117] (10) Mold fouling resistance Pellets of the PPS resin composition of the present invention 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-30D) set at a cylinder temperature of 320°C and a mold temperature of 130°C. Using a mold deposit evaluation mold, molded articles for mold deposit evaluation 1 shown in Figure 1 were continuously molded to evaluate mold deposits. Figure 1(a) is a top view of molded article 1 for mold deposit evaluation, and Figure 1(b) is a side view. Using a mold deposit evaluation mold (molded article 1: length 55 mm, width 20 mm, thickness 2 mm; gate 2: width 2 mm, thickness 1 mm; maximum gas vent length 20 mm, width 10 mm, depth 5 μm), continuous molding was performed at an injection speed of 100 mm / s and an injection pressure set to achieve a filling time of 0.4 seconds. The mold gas vent and cavity were visually inspected for mold contamination every 10 shots. The more shots required to produce mold stains, the less mold deposits there will be, and the more preferable it is. A shot count of 100 or more is considered to be at a practically usable level. 150 or more shots required to produce mold stains were rated as 1, 100 to 150 shots as 2, 50 to 100 shots as 3, and less than 50 shots as 4.

[0118] (A)PPS resin [Reference Example 1] Preparation of PPS(A)-1 A 70-liter autoclave equipped with a stirrer was charged with 8,267.37 g (70.00 mol) of 47.5% sodium hydrosulfide, 2,957.21 g (70.97 mol) of 96% sodium hydroxide, 11,434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 2,583.00 g (31.50 mol) of sodium acetate, and 10,500 g of ion-exchanged water. The mixture was gradually heated to 245°C over approximately 3 hours under atmospheric pressure while passing nitrogen through. After distilling off 14,780.1 g of water and 280 g of NMP, the reactor 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 0.02 mol per mole of charged alkali metal sulfide.

[0119] Next, 10204.74 g (69.42 mol) of p-dichlorobenzene (p-DCB) and 9.00 g (91.00 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. The mixture was stirred at 240 rpm and heated to 238°C at a rate of 0.6°C / min. After 95 minutes of reaction at 238°C, the mixture was heated to 270°C at a rate of 0.8°C / min. After 100 minutes of reaction at 270°C, the mixture was cooled to 250°C at a rate of 1.3°C / min while injecting 1260 g (70 mol) of water over 15 minutes. The mixture was then cooled to 200°C at a rate of 1.0°C / min and rapidly cooled to near room temperature.

[0120] The contents were removed from the reactor and diluted with 26,300 g of NMP. The solvent and solids were filtered through an 80-mesh sieve. The resulting particles were washed with 31,900 g of NMP and then filtered. They were washed and filtered several times with 56,000 g of ion-exchanged water, then washed and filtered with 70,000 g of 0.05 wt.% acetic acid aqueous solution. After washing and filtering with another 70,000 g of ion-exchanged water, the resulting hydrous PPS particles were dried with hot air at 80°C and then vacuum-dried at 120°C. The resulting PPS (A)-1 had a melt viscosity of 220 Pa·s and an ash content of 0.04%.

[0121] [Reference Example 2] Preparation of PPS(A)-2 Except for using 10,235.46 g (69.63 mol) of p-dichlorobenzene (p-DCB), PPS was prepared in the same manner as in Reference Example 1. The resulting PPS (A)-2 had a melt viscosity of 200 Pa s and an ash content of 0.04%.

[0122] [Reference Example 3] Preparation of PPS(A)-3 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 NMP, 2.58 kg (31.5 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 off. 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, leaving 68.6 mol of sulfidizing agent in the system after this dehydration step. With the release of hydrogen sulfide, an additional 1.4 mol of sodium hydroxide was generated in the system.

[0123] Next, 10.24 kg (69.6 mol) of p-DCB and 9.37 kg (94.5 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. The mixture was heated from 200°C to 235°C while stirring. Polymerization was carried out for 120 minutes at 235°C, followed by heating to 255°C. 1.00 kg (56.0 mol) of ion-exchanged water was then injected, and polymerization reaction was carried out for 300 minutes at 255°C. After completion of the reaction, the mixture was cooled to 200°C at a rate of 1.0°C / min and then rapidly cooled to near room temperature. The reaction product 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 net to obtain a solid. The obtained solid was washed with NMP and filtered as in Reference Example 1. The obtained solid was diluted with ion-exchanged water, stirred for 30 minutes at 70°C, and then filtered through an 80-mesh wire net to recover 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 was collected by filtration through an 80-mesh wire screen. The solid thus obtained was dried at 120°C under a nitrogen stream to obtain PPS(A)-3 with a melt viscosity of 300 Pa s and an ash content of 0.21%.

[0124] [Reference Example 4] Preparation of PPS(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 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 were 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.

[0125] Next, 10.33 kg (70.2 mol) of p-DCB, 0.025 kg (0.14 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, then rapidly cooled to near room temperature, washed, and dried in the same manner as in Reference Example 3 to obtain PPS(A)-4 with a melt viscosity of 760 Pa s and an ash content of 0.25%.

[0126] (B) Olefin-based elastomer resin B-1: Ethylene-glycidyl methacrylate copolymer (Sumitomo Chemical Co., Ltd., Bondfast E) B-2: Ethylene-1-butene copolymer (Tafmer (registered trademark) A0550S, manufactured by Mitsui Chemicals, Inc.).

[0127] (C) Alkoxysilane compound containing an amino group γ-aminopropyltriethoxysilane (KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.) (D) Alkoxysilane compound premix A portion of (A) PPS-1 obtained in Reference Example 1 above was dry-blended with (C) γ-aminopropyltriethoxysilane in the weight ratio shown in Table 2 to obtain (D) an alkoxysilane compound premix.

[0128] (Production of PPS resin composition) Using a 26 mm diameter twin-screw extruder (TEM-26SS manufactured by Toshiba Machine Co., Ltd.) with a cylinder temperature set to 300°C and a screw rotation speed set to 300 rpm, (A) PPS resin, (B) olefin-based elastomer resin, and (C) alkoxysilane compound shown in Tables 1 and 2 were dry-blended in the weight ratios shown in Tables 1 and 2, fed through the raw material feed port, and melt-kneaded at a discharge rate of 40 kg / hour to obtain pellets. When an alkoxysilane premix (D) was used as a raw material, the raw material obtained by dry-blending (A) PPS resin and (B) olefin-based elastomer resin in amounts subtracted from the amount used in the premix, and the alkoxysilane premix (D) were each fed separately through the raw material feed ports.

[0129] The pellets thus obtained were used to evaluate the above-mentioned properties, and the results are shown in Tables 1 and 2.

[0130] [Table 1]

[0131] [Table 2]

[0132] Examples 1 to 13 The PPS resin compositions of Examples 1 to 13 shown in Tables 1 and 2 had good impact resistance, low flash, and low gas content with loss on heating of 0.8% by weight or less.

[0133] Comparative Example 1 In Comparative Example 1 shown in Table 2, the melt viscosity of the PPS resin composition was less than 120 Pa·s, and therefore the low flash property was poor.

[0134] Comparative Example 2 In Comparative Example 2 shown in Table 2, the amount of olefin-based elastomer added exceeded 25 parts by weight, and the melt viscosity exceeded 200 Pa·s, so the low gassing property, moldability, and mechanical strength were poor.

[0135] Comparative Example 3 Comparative Example 3 shown in Table 2 had poor impact resistance because the amount of olefin-based elastomer added was less than 3 parts by weight.

[0136] Comparative Example 4 In Comparative Example 4 shown in Table 2, the melt viscosity of the PPS resin composition exceeded 200 Pa·s and the loss on heating exceeded 0.8% by weight, so that the molding processability and low gassing properties were poor. [Industrial Applicability]

[0137] The polyphenylene sulfide resin composition of the present invention has excellent impact resistance, low flash properties, and low gas production, and is therefore preferably applicable to applications such as electrical and electronic equipment, precision machinery equipment, office equipment, automotive and vehicle parts, building materials, packaging materials, furniture, and daily necessities. [Explanation of symbols]

[0138] 1. Molded product for mold deposit evaluation 2. Gate

Claims

1. A polyphenylene sulfide resin composition comprising 100 parts by weight of (A) polyphenylene sulfide resin having a melt viscosity of more than 200 Pa·s at a temperature of 310°C, an orifice length L to orifice diameter D ratio of 10, and a shear rate of 1216 / s, and 3 to 25 parts by weight of (B) olefin-based elastomer resin, wherein the (A) polyphenylene sulfide resin has a branched structure and / or a crosslinked structure derived from a polyhalogenated aromatic compound having three or more halogen substituents per molecule, and the (B) olefin-based elastomer resin a polyphenylene sulfide resin composition comprising a combination of (B-1) an α-olefin copolymer having an epoxy group and (B-2) an olefin (co)polymer having no polar functional group, wherein the (B-2) olefin (co)polymer having no polar functional group is an ethylene / 1-butene copolymer, and wherein the melt viscosity at a temperature of 320°C, an orifice length L to an orifice diameter D ratio of 40 (L / D) and a shear rate of 4700 / s is 120 Pa s or more and 200 Pa s or less, and wherein the loss on heat when heated at 320°C for 2 hours in an air atmosphere is 0.8 wt % or less.

2. 2. The polyphenylene sulfide resin composition according to claim 1, wherein the polyphenylene sulfide resin (A) contains (A1) a polyphenylene sulfide resin having an ash content of 0.10% by weight or less and (A2) a polyphenylene sulfide resin having an ash content of 0.20% by weight or more.

3. 3. The polyphenylene sulfide resin composition according to claim 1, further comprising 0.05 to 3.0 parts by weight of an alkoxysilane compound having an amino group (C) blended with 100 parts by weight of the polyphenylene sulfide resin (A).

4. A method for producing a polyphenylene sulfide resin composition as described in claim 3, comprising the steps of: premixing 1 to 25 parts by weight of 100 parts by weight of the (A) polyphenylene sulfide resin with 0.05 to 3.0 parts by weight of an alkoxysilane compound having an amino group (C) to prepare a (D) alkoxysilane compound premix; and separately supplying the (D) alkoxysilane compound premix and the remaining 99 to 75 parts by weight of the (A) polyphenylene sulfide resin to an extruder.

5. 5. The method for producing a polyphenylene sulfide resin composition according to claim 4, wherein the moisture content of the polyphenylene sulfide resin (A) to be fed to the extruder is 1% by weight or less.

6. A method for producing a polyphenylene sulfide resin composition, comprising blending 100 parts by weight of (A) polyphenylene sulfide resin having a melt viscosity of more than 200 Pa·s at a temperature of 310°C, an orifice length L to orifice diameter D ratio of 10, and a shear rate of 1216 / s, with 3 to 25 parts by weight of (B) an olefin-based elastomer resin and 0.05 to 3.0 parts by weight of (C) an alkoxysilane compound having an amino group, wherein 1 to 25 parts by weight of the 100 parts by weight of the (A) polyphenylene sulfide resin and 0.05 to 3.0 parts by weight of the (C) alkoxysilane compound having an amino group are blended. and 0.05 to 3.0 parts by weight of a silane compound to prepare a premixed (D) alkoxysilane compound; and feeding the premixed (D) alkoxysilane compound and the remaining 99 to 75 parts by weight of the polyphenylene sulfide resin (A) separately to an extruder, wherein the polyphenylene sulfide resin (A) contains (A1) a polyphenylene sulfide resin having an ash content of 0.10% by weight or less and (A2) a polyphenylene sulfide resin having an ash content of 0.20% by weight or more.

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