WO2023218850A1

WO2023218850A1 - Polyarylene sulfide resin composition, molded article, and methods for producing said polyarylene sulfide resin composition and molded article

Info

Publication number: WO2023218850A1
Application number: PCT/JP2023/014952
Authority: WO
Inventors: 隆平黒川
Original assignee: Dic株式会社
Priority date: 2022-05-10
Filing date: 2023-04-13
Publication date: 2023-11-16
Also published as: JPWO2023218850A1

Abstract

The present invention provides a polyarylene sulfide (PAS) resin molded article that has excellent thermal conductivity and mechanical characteristics and suppresses wear of materials in a sliding environment, a PAS resin composition that can provide said molded article, and methods for producing the resin composition and the molded article. More specifically, a PAS resin composition for a sliding member, obtained by blending a PAS resin with graphite, the PAS resin composition being characterized in that the melt viscosity (V6) of the PAS resin is 90-350 Pa∙s inclusive, the graphite is scaly, the amount of graphite blended is 5-50 mass parts per 100 mass parts of the resin composition, and the MD/TD ratio of the linear expansion coefficients of the resin composition is 0.5 or more; a molded article; and methods for producing the resin composition and the molded article.

Description

Polyarylene sulfide resin compositions, molded products and methods for producing them

The present invention relates to polyarylene sulfide resin compositions, polyarylene sulfide resin molded articles, and methods for producing them.

In recent years, engineering plastics have been developed that have excellent productivity, moldability, and high heat resistance, and because they are lightweight, they are widely used as materials for electrical and electronic equipment, automobiles, etc. as an alternative to metal materials. In particular, polyarylene sulfide (hereinafter referred to as PAS) resins, represented by polyphenylene sulfide (hereinafter referred to as PPS) resins, have excellent heat resistance, mechanical strength, chemical resistance, moldability, and dimensional stability. Because of its excellent properties, it is widely used in fields such as automobile parts and electrical and electronics.

On the other hand, as the replacement of metals with resin materials progresses, there is an increasing demand for resin materials with low friction coefficients and low abrasion properties for use in sliding surfaces such as bearings and gears. As a PAS resin material used as a sliding material, for example, a material containing carbon fiber, fluororesin, graphite, and metal sulfide is known (see, for example, Patent Document 1). However, when a material with a relatively high Mohs hardness, such as carbon fiber, is used, there is a drawback that the friction coefficient and the amount of wear of the resin composition become large. Further, PAS resin materials using inorganic fillers having a Mohs hardness of 3.5 or less are known (for example, Patent Document 2).

JP2019-85470A Japanese Patent Application Publication No. 2002-332406

However, although these methods improve the sliding properties of the resulting resin compositions and molded products, they have insufficient heat dissipation properties and mechanical properties, and resins that exhibit excellent sliding properties and strength even in high-temperature environments are insufficient. It was not possible to obtain a satisfactory molded product.

Therefore, the problem to be solved by the present invention is to provide a PAS molded product that has excellent thermal conductivity and mechanical properties and suppresses wear of the material in a sliding environment, and a PAS resin composition that can provide the molded product. and a method for producing them.

As a result of intensive studies to solve the above problems, the present inventors combined flaky graphite with a PAS resin that exhibits a melt viscosity within a specific range, and achieved a linear expansion coefficient MD/TD ratio of 0.7 or more. The present inventors have discovered that a resin composition has excellent thermal conductivity and mechanical properties, and suppresses material wear in a sliding environment, leading to the completion of the present invention.

That is, the present disclosure provides a PAS resin composition for sliding members which is a mixture of PAS resin (A) and graphite (B), wherein the PAS resin (A) has a melt viscosity (V6) of 90 Pa·s or more and 350 Pa·s or less, the graphite (B) is in the form of scales, and the amount of graphite (B) blended in 100 parts by mass of the resin composition is 5 to 50 parts by mass, and the linear expansion coefficient of the resin composition is The present invention relates to a PAS resin composition for sliding members, which has a MD/TD ratio of 0.5 or more.

The present disclosure also relates to a PAS resin molded article for a sliding member formed by molding the PAS resin composition described above.

The present disclosure also relates to a sliding member made of the molded product described above.

The present disclosure also provides a method for producing a PAS resin composition for sliding members, which includes a step of blending PAS resin (A) and graphite (B) and melting and kneading the mixture at a temperature range equal to or higher than the melting point of PAS resin (A). The melt viscosity of the PAS resin (A) is 90 Pa·s or more and 350 Pa·s or less, the graphite (B) is scaly, and the graphite (B) in 100 parts by mass of the resin composition is The present invention relates to a method for producing a PAS resin composition for sliding members, characterized in that the blending amount is 5 to 50 parts by mass, and the ratio of MD/TD of linear expansion coefficient of the resin composition is 0.5 or more.

The present disclosure also relates to a method for manufacturing a molded article for a sliding member, which includes a step of manufacturing a PAS resin composition using the manufacturing method described above, and a step of melt-molding the obtained PAS resin composition.

According to the present invention, there is provided a PAS resin molded product for a sliding member that includes PAS resin and flaky graphite, has excellent thermal conductivity and mechanical properties, and suppresses wear of the material in a sliding environment. It is possible to provide PAS resin compositions for sliding members that can be made into molded products and methods for producing them.

The PAS resin composition according to the present embodiment is a PAS resin composition for sliding members made by blending PAS resin (A) and graphite (B), and the melt viscosity (V6) of the PAS resin (A) is 90 Pa·s or more and 350 Pa·s or less, the graphite (B) is in the form of scales, and the blending amount of graphite (B) in 100 parts by mass of the resin composition is 5 to 50 parts by mass, and the resin composition The product is characterized by having a linear expansion coefficient MD/TD ratio of 0.5 or more. This will be explained below.

<PAS resin (A)>
The PAS resin composition according to this embodiment contains a PAS resin as an essential component.

PAS resin has a resin structure in which the repeating unit is a structure in which an aromatic ring and a sulfur atom are bonded, and specifically, it has the following general formula (1)

(In the formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a nitro group, an amino group, a phenyl group, a methoxy group, or an ethoxy group.) and, if necessary, the following general formula (2)

It is a resin whose repeating unit is a trifunctional structural moiety represented by the following. The trifunctional structural moiety represented by formula (2) preferably ranges from 0.001 to 3 mol%, particularly from 0.01 to 1 mol%, based on the total number of moles with other structural moieties. It is preferable that

Here, in the structural moiety represented by the general formula (1), particularly R ¹ and R ² in the formula are preferably hydrogen atoms from the viewpoint of mechanical strength of the PAS resin, in which case, Examples include those bonded at the para position represented by the following formula (3), and those bonded at the meta position represented by the following formula (4).

Among these, the structure in which the sulfur atom is bonded to the aromatic ring in the repeating unit at the para position represented by the general formula (3) is particularly important in terms of heat resistance and crystallinity of the PAS resin. preferable.

In addition, the PAS resin has not only the structural parts represented by the general formulas (1) and (2), but also the following structural formulas (5) to (8).

The structural moiety represented by the above may be contained in an amount of 30 mol% or less of the total of the structural moieties represented by the general formula (1) and the general formula (2). In particular, in the present disclosure, it is preferable that the content of the structural moieties represented by the above general formulas (5) to (8) is 10 mol % or less from the viewpoint of heat resistance and mechanical strength of the PAS resin. When the PAS resin contains structural moieties represented by the above general formulas (5) to (8), their bonding mode may be either a random copolymer or a block copolymer.

Further, the PAS resin may have a naphthyl sulfide bond or the like in its molecular structure, but it is preferably 3 mol% or less, particularly 1 mol% or less, based on the total number of moles with other structural parts. It is preferable that it is below.

Further, the physical properties of the PAS resin are not particularly limited as long as they do not impair the effects of the present invention, but are as follows.

(melt viscosity)
Although the melt viscosity of the PAS resin used in this embodiment is not particularly limited, it is preferable that the melt viscosity (V6) measured at 300°C is 2 Pa·s or more because it provides a good balance between fluidity and mechanical strength. It is preferably in a range of 1000 Pa·s or less, more preferably in a range of 500 Pa·s or less, still more preferably in a range of 300 Pa·s or less. However, the melt viscosity (V6) of the PAS resin was measured using a Shimadzu flow tester, CFT-500D, at 300°C, load: 1.96 x 10 ⁶ Pa, L/D = 10 (mm)/ This is the measured value of melt viscosity measured after holding at 1 (mm) for 6 minutes.

(non-Newtonian index)
The non-Newtonian index of the PAS resin used in this embodiment is not particularly limited, but is preferably in the range of 0.90 or more and 2.00 or less. When using a linear PAS resin, the non-Newtonian index is preferably in the range of 0.90 or more, more preferably in the range of 0.95 or more, and preferably in the range of 1.50 or less, more preferably 1. It is in the range of 20 or less. Such PAS resins have excellent mechanical properties, fluidity, and abrasion resistance. However, in the present disclosure, the non-Newtonian exponent (N value) is determined using a capillograph under the conditions of melting point +20°C, ratio of orifice length (L) to orifice diameter (D), and shear rate (SR ) and shear stress (SS) were measured and calculated using the following formula. The closer the non-Newtonian index (N value) is to 1, the more linear the structure is, and the higher the non-Newtonian index (N value) is, the more branched the structure is.

[where SR is shear rate (sec ^-1 ), SS is shear stress (dynes/cm ² ), and K is a constant. ]

(Production method)
The method for producing the PAS resin is not particularly limited, but for example (Production method 1) a dihalogeno aromatic compound is added in the presence of sulfur and sodium carbonate, and if necessary, a polyhalogeno aromatic compound or other copolymerization component is added, Polymerization method, (Production method 2) A method of polymerizing a dihalogeno aromatic compound in the presence of a sulfidating agent, etc. in a polar solvent, and adding a polyhalogeno aromatic compound or other copolymerization components if necessary. Method 3) A method in which p-chlorothiophenol is self-condensed by adding other copolymerization components if necessary, (Production method 4) A diiodo aromatic compound and elemental sulfur are combined with a functional group such as a carboxy group or an amino group. Examples include a method in which melt polymerization is carried out under reduced pressure in the presence of a polymerization inhibitor that may contain. Among these methods, the method (manufacturing method 2) is preferred because it is versatile. During the reaction, an alkali metal salt of carboxylic acid or sulfonic acid, or an alkali hydroxide may be added to adjust the degree of polymerization. Among the above methods (Production method 2), a hydrous sulfidating agent is introduced into a heated mixture containing an organic polar solvent and a dihalogeno aromatic compound at a rate that allows water to be removed from the reaction mixture, and the dihalogeno aromatic compound is The aromatic compound and the sulfidating agent are added and reacted with the polyhalogeno aromatic compound as necessary, and the amount of water in the reaction system is adjusted to 0.02 to 0.5 mol per mol of the organic polar solvent. A method for producing PAS resin (see JP-A-07-228699) by controlling the range of For example, a polyhalogeno aromatic compound or other copolymerization component is added, and an alkali metal hydrosulfide and an alkali metal salt of an organic acid are added in an amount of 0.01 to 0.9 mol per mol of the sulfur source. Particularly preferred are those obtained by a method in which the reaction is carried out while controlling the amount of water in the reaction system within a range of 0.02 mol or less per 1 mol of the aprotic polar organic solvent (see WO2010/058713 pamphlet). Specific examples of dihalogeno aromatic compounds include p-dihalobenzene, m-dihalobenzene, o-dihalobenzene, 2,5-dihalotoluene, 1,4-dihalonaphthalene, 1-methoxy-2,5-dihalobenzene, 4, 4'-dihalobiphenyl, 3,5-dihalobenzoic acid, 2,4-dihalobenzoic acid, 2,5-dihalonitrobenzene, 2,4-dihalonitrobenzene, 2,4-dihaloanisole, p,p '-Dihalodiphenyl ether, 4,4'-dihalobenzophenone, 4,4'-dihalodiphenylsulfone, 4,4'-dihalodiphenylsulfoxide, 4,4'-dihalodiphenylsulfide, and each of the above compounds Examples of polyhalogeno aromatic compounds include 1,2,3-trihalobenzene, 1,2,4-trihalobenzene, 1,3, Examples include 5-trihalobenzene, 1,2,3,5-tetrahalobenzene, 1,2,4,5-tetrahalobenzene, and 1,4,6-trihalonaphthalene. Further, the halogen atom contained in each of the above compounds is preferably a chlorine atom or a bromine atom.

The method for post-treatment of the reaction mixture containing the PAS resin obtained in the polymerization process is not particularly limited, but for example, (Post-treatment 1) After the polymerization reaction is completed, the reaction mixture is first treated as it is or treated with an acid or base. After adding, the solvent is distilled off under reduced pressure or normal pressure, and the solid after solvent distillation is mixed with water, reaction solvent (or organic solvent with equivalent solubility for low-molecular polymers), acetone, methyl ethyl ketone. , a method of washing with a solvent such as alcohol once or twice or more, and further neutralizing, washing with water, filtering and drying, or (Post-treatment 2) After the polymerization reaction is completed, the reaction mixture is added with water, acetone, methyl ethyl ketone, or alcohol. Solvents such as esters, ethers, halogenated hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons (solvents that are soluble in the polymerization solvent used and are at least poor solvents for PAS) as precipitants. Alternatively, (post-treatment 3) after the completion of the polymerization reaction, a reaction solvent (or low molecular weight After stirring, filtering to remove low molecular weight polymers, and washing once or twice with a solvent such as water, acetone, methyl ethyl ketone, alcohol, etc. (Post-processing 4) After the polymerization reaction is completed, water is added to the reaction mixture, and the reaction mixture is washed with water, filtered, and if necessary, an acid is added during the water washing. (Post-treatment 5) After the completion of the polymerization reaction, the reaction mixture is filtered, if necessary, washed with a reaction solvent once or twice or more, and further washed with water, filtered and dried, etc. Among these methods, the method (post-treatment 4) can effectively remove metal atoms such as sodium present at the molecular ends of PAS resin, and it is possible to obtain PAS resin with low sodium content. preferable.

In addition, in the post-treatment methods exemplified in (Post-treatment 1) to (Post-treatment 5) above, the PAS resin may be dried in vacuum, in air or in an inert gas atmosphere such as nitrogen. You can also do it with

The amount of PAS resin blended in the PAS resin composition of this embodiment is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 50 parts by mass or more, more preferably 60 parts by mass, based on 100 parts by mass of the resin composition. The amount ranges from at least 65 parts by mass, more preferably at least 65 parts by mass, to at most 90 parts by mass, more preferably at most 80 parts by mass, even more preferably at most 75 parts by mass. This range is preferable because the resin composition exhibits good wear resistance.

<Graphite (B)>
The PAS resin composition according to this embodiment contains graphite (B) as an essential component. The graphite (B) used in this embodiment preferably has a scaly shape.

Graphite can be broadly classified into natural graphite and artificial graphite, and either of these may be used in this embodiment. The graphite used in the resin composition according to the present embodiment preferably has a fixed carbon content of 95% or more, and more preferably has a fixed carbon content of 98% or more. Further, the crystallinity of graphite is preferably 80% or more, more preferably 90% or more. By using graphite with a high fixed carbon content and high crystallinity, a resin composition with particularly good thermal conductivity can be obtained.

The average particle diameter (D ₅₀ ) of graphite (B) used in this embodiment is not particularly limited, but it is preferable that the average particle diameter (D ₅₀ ) of the primary particles is in the range of 0.5 μm or more, The range is preferably 500 μm or less. When the particle size of graphite (B) is within this range, it is possible to obtain a resin composition that has particularly excellent balance between fluidity during melting and mechanical properties. The average particle size is the average particle size (D50) determined based on the particle size distribution measured according to a conventional method using a laser diffraction scattering particle size distribution analyzer (Microtrac MT3300EXII).

The amount of graphite (B) blended in the PAS resin composition of the present invention is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 5 parts by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the resin composition. The amount ranges from 10 parts by weight or more, preferably 100 parts by weight or less, more preferably 50 parts by weight or less, still more preferably 30 parts by weight or less. This range is preferable because the resin composition has good processability and the molded product has excellent wear resistance and thermal conductivity.

The PAS resin composition according to this embodiment is a PPS resin composition that does not substantially contain a fibrous reinforcing material, but a small amount of fibrous filler is added as an optional component within a range that does not impair the effects of the present invention. can do. As these fibrous fillers, known and commonly used materials can be used as long as they do not impair the effects of the present invention. For example, glass fibers, carbon fibers, silane glass fibers, ceramic fibers, aramid fibers, metal fibers, etc. are used. can. When blending a fibrous filler, the blending amount is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, based on 100 parts by mass of graphite (B). In this range, the anisotropy of the linear expansion coefficient of the resin composition can be suppressed, so the ratio of MD/TD of the linear expansion coefficient becomes large, and the abrasion resistance is excellent.

The PAS resin composition according to the present embodiment may contain a non-fibrous filler as an optional component within a range that does not impair the effects of the present invention. For example, fillers of various shapes such as plate-like and spherical shapes can be mentioned. Specifically, glass beads, glass flakes, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, attapulgite, ferrite, calcium silicate, zeolite, boehmite, etc. Non-fibrous fillers can be used.

Although a non-fibrous filler is not an essential component in the present disclosure, if it is blended, the amount of the filler blended is not particularly limited as long as it does not impair the effects of the present invention. The amount of other fillers to be added is, for example, preferably 1 part by mass or more, more preferably 5 parts by mass or more, preferably 600 parts by mass or less, based on 100 parts by mass of the PAS resin (A). The amount is preferably 200 parts by mass or less. This range is preferable because the resin composition exhibits good moldability and the molded product has excellent mechanical properties.

The PAS resin composition according to the present embodiment may contain a silane coupling agent as an optional component, if necessary. The PAS resin silane coupling agent of the present disclosure is not particularly limited as long as it does not impair the effects of the present invention, but the silane coupling agent has a functional group that reacts with a carboxy group, such as an epoxy group, an isocyanato group, an amino group, or a hydroxyl group. Agents are listed as preferred. Examples of such silane coupling agents include epoxy groups such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Containing alkoxysilane compounds, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane , γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane and other isocyanato group-containing alkoxysilane compounds, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)amino Examples include amino group-containing alkoxysilane compounds such as propyltrimethoxysilane and γ-aminopropyltrimethoxysilane, and hydroxyl group-containing alkoxysilane compounds such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane. In the present disclosure, the silane coupling agent is not an essential component, but if it is blended, the amount added is not particularly limited as long as it does not impair the effects of the present invention, but it can be added to 100 parts by mass of the PAS resin (A). The amount is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less. This range is preferable because the resin composition has good corona resistance and moldability, especially mold releasability, and the molded product exhibits excellent adhesion to the epoxy resin while further improving mechanical strength.

The PAS resin composition according to this embodiment may contain a thermoplastic elastomer as an optional component, if necessary. Examples of the thermoplastic elastomer include polyolefin elastomers, fluorine elastomers, and silicone elastomers, and among these, polyolefin elastomers are preferred. When adding these elastomers, the blending amount is not particularly limited as long as it does not impair the effects of the present invention, but it is preferably 0.01 parts by mass or more, more preferably 0.01 parts by mass or more, based on 100 parts by mass of PAS resin (A). The amount ranges from 0.1 parts by weight or more to preferably 10 parts by weight or less, more preferably 5 parts by weight or less. This range is preferable because the impact resistance of the resulting PAS resin composition is improved.

For example, the polyolefin elastomer may be a homopolymer of α-olefin, a copolymer of two or more α-olefins, or a copolymer of one or more α-olefins and a vinyl polymerizable compound having a functional group. One example is merging. In this case, the α-olefin includes α-olefins having a carbon atom number ranging from 2 to 8, such as ethylene, propylene, and 1-butene. Further, examples of the functional group include a carboxy group, an acid anhydride group (-C(=O)OC(=O)-), an epoxy group, an amino group, a hydroxyl group, a mercapto group, an isocyanate group, an oxazoline group, etc. . Examples of vinyl polymerizable compounds having the functional group include vinyl acetate; α,β-unsaturated carboxylic acids such as (meth)acrylic acid; Alkyl esters of unsaturated carboxylic acids; metal salts of α, β-unsaturated carboxylic acids such as ionomers (metals include alkali metals such as sodium, alkaline earth metals such as calcium, zinc, etc.); α, β-unsaturated carboxylic acids such as ionomers; Glycidyl esters of β-unsaturated carboxylic acids; α,β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid; derivatives of the α,β-unsaturated dicarboxylic acids (monoesters, diesters, acid anhydrides, etc.); ), etc., or two or more thereof. The above-mentioned thermoplastic elastomers may be used alone or in combination of two or more.

Furthermore, in addition to the above components, the PAS resin composition according to the present embodiment may further contain polyester resin, polyamide resin, polyimide resin, polyetherimide resin, polycarbonate resin, polyphenylene ether resin, polysulfone, as appropriate depending on the application. Resin, polyether sulfone resin, polyether ether ketone resin, polyether ketone resin, polyarylene resin, polyethylene resin, polypropylene resin, polytetrafluoroethylene resin, polydifluoroethylene resin, polystyrene resin, ABS resin, epoxy resin , phenol resin, urethane resin, liquid crystal polymer, and other synthetic resins (hereinafter simply referred to as synthetic resins) can be blended as optional components. In particular, it is preferable to incorporate a fluororesin because the sliding properties are further improved. In the present disclosure, the synthetic resin is not an essential component, but if it is blended, the blending ratio is not particularly limited as long as it does not impair the effects of the present invention, and it varies depending on the purpose of the invention, so it cannot be generalized. Although it cannot be specified, the proportion of the synthetic resin blended in the resin composition according to the present embodiment is, for example, in the range of 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of PAS resin (A). Examples include degrees of range. In other words, the ratio of PAS resin to the total of PAS resin (A) and synthetic resin is preferably in the range of (100/115) or more, and more preferably in the range of (100/105) or more, based on mass. range.

In addition, the PAS resin composition according to the present embodiment can also be used as a colorant, an antistatic agent, an antioxidant, a heat stabilizer, an ultraviolet stabilizer, an ultraviolet absorber, a blowing agent, a flame retardant, a flame retardant aid, and a flame retardant. Any known and commonly used additives such as rusting agents and mold release agents (metal salts and esters of fatty acids having 18 to 30 carbon atoms, including stearic acid and montanic acid, and polyolefin waxes such as polyethylene) may be added as necessary. It may be added as a component. These additives are not essential components and, for example, are preferably in the range of 0.01 parts by mass or more, and preferably 1000 parts by mass or less, more preferably 100 parts by mass, based on 100 parts by mass of the PAS resin (A). It may be used in a range of not more than 10 parts by mass, more preferably not more than 10 parts by mass, depending on the purpose and application so as not to impair the effects of the present invention.

Furthermore, the PAS resin composition according to the present embodiment is characterized in that the ratio of linear expansion coefficient MD/TD is 0.5 or more. The method for adjusting the coefficient of linear expansion is not particularly limited, and the type, molecular weight, melt viscosity, content, etc. of the PAS resin contained in the resin composition, the type and content of graphite and other fillers or additives, etc. can be adjusted in various ways. This can be done by adjusting. An example of a method for increasing the MD/TD ratio is to reduce the amount of a filler with a large aspect ratio, such as a fibrous filler. This is because when the blending amount of a filler with a large aspect ratio is increased, the coefficient of linear thermal expansion in the TD direction tends to become larger than that in the MD direction.

In the range of the MD/TD ratio of the linear expansion coefficient of the PAS resin composition, it is possible to suppress the anisotropy of expansion of the resin composition due to frictional heat generated during sliding, and therefore it is possible to suppress wear. can. Note that the MD/TD ratio of the linear expansion coefficient in the present disclosure is determined by measuring the length of the central part of the ISO Type 1A dumbbell-shaped test piece in the resin flow direction (MD) and in the direction perpendicular to the flow direction (TD), respectively, by 10 mm; This is a value calculated using a test piece cut into a rectangular parallelepiped with a width of 10 mm and a thickness of 4 mm, and measured in a temperature range of 145 to 155° C. in accordance with ISO 11359-2. The closer MD/TD is to 1, the smaller the anisotropy of the linear expansion coefficient.

Furthermore, the PAS resin composition according to this embodiment has excellent thermal conductivity. Although the thermal conductivity is not particularly limited, it is preferably 0.5 [W/m·K] or more, and more preferably 0.6 [W/m·K] or more. In this range, melting of the resin due to frictional heat generated during sliding can be reduced, and therefore wear of the molded product can be reduced. Further, it is possible to suppress a decrease in mechanical strength and deterioration of the material in a high-temperature environment. The thermal conductivity in this disclosure is measured in the thickness direction of the molded product by the method described in the Examples, according to ISO 22007-2 "Plastics - How to determine thermal conductivity and thermal diffusivity - Part 2: Transient planar heat source. (Hot Disk) Method.

<Method for manufacturing PAS resin composition>
The method for producing a PAS resin composition according to the present embodiment is a sliding member having a step of blending PAS resin (A) and graphite (B) and melting and kneading the mixture in a temperature range equal to or higher than the melting point of PAS resin (A). A method for producing a PAS resin composition for use, comprising:
The melt viscosity of the PAS resin (A) is 90 Pa·s or more and 350 Pa·s or less, the graphite (B) is scaly, and the blending amount of graphite (B) in 100 parts by mass of the resin composition is 5 to 5. 50 parts by mass, and the ratio of MD/TD of linear expansion coefficient of the resin composition is 0.5 or more. The details will be explained below.

The method for producing a PAS resin composition according to the present embodiment includes the step of blending the above-mentioned essential components and melting and kneading them at a temperature range equal to or higher than the melting point of the PAS resin (A). More specifically, the PAS resin composition according to the present embodiment is formed by blending each essential component and other optional components as necessary. The method for producing the resin composition according to the present embodiment is not particularly limited, but includes a method of blending essential components and optional components as necessary, and melting and kneading the mixture, more specifically, using a tumbler or Examples include a method of uniformly dry mixing using a Henschel mixer or the like, then introducing the mixture into a twin-screw extruder and melt-kneading it.

Melt kneading is carried out in a temperature range in which the resin temperature is equal to or higher than the melting point of the PAS resin (A), preferably in a temperature range in which the melting point is +10°C or higher, more preferably at least the melting point +10°C, even more preferably at least the melting point +20°C. This can be carried out by heating to a temperature in the range from 100° C. to 100° C., more preferably 50° C. below the melting point.

The melt-kneading machine is preferably a twin-screw kneading extruder from the viewpoint of dispersibility and productivity, for example, a discharge rate of the resin component in the range of 5 to 500 (kg/hr) and a screw rotation speed of 50 to 500 (rpm). It is preferable to melt and knead while appropriately adjusting the range, and melt and knead under conditions such that the ratio (discharge amount/screw rotation speed) is in the range of 0.02 to 5 (kg/hr/rpm). is even more preferable. Further, the addition and mixing of each component to the melt-kneading machine may be performed simultaneously or may be performed separately. For example, when adding graphite (B), which is an essential component, and other fibrous fillers as necessary, it is preferable to introduce the two-screw extruder from the side feeder into the extruder. Preferable from a gender perspective. The position of the side feeder is preferably such that the ratio of the distance from the extruder resin input part (top feeder) to the side feeder to the total screw length of the twin-screw kneading extruder is 0.1 or more, and 0. More preferably, it is .3 or more. Moreover, it is preferable that this ratio is 0.9 or less, and it is more preferable that it is 0.7 or less.

The PAS resin composition according to the present embodiment obtained by melt-kneading in this manner is a molten mixture containing the above-mentioned essential components, optional components added as necessary, and components derived from these components. Therefore, the PAS resin composition according to the present embodiment has a morphology in which the PAS resin (A) forms a continuous phase and other essential components and optional components are dispersed. After the melt-kneading, the PAS resin composition according to the present embodiment is produced by a known method, for example, by extruding the molten resin composition into a strand shape, and then processing it into pellets, chips, granules, powder, etc. After that, it is preferable to perform preliminary drying at a temperature range of 100 to 150°C, if necessary.

<PAS resin molded product, manufacturing method of PAS resin molded product>
The molded article according to this embodiment is formed by melt-molding a PAS resin composition. Moreover, the method for manufacturing a molded article according to the present embodiment includes a step of melt-molding the PAS resin composition. Therefore, the molded article according to this embodiment has a morphology in which the PAS resin (A) forms a continuous phase and other essential components and optional components are dispersed. When the PAS resin composition has such a morphology, a molded article with excellent thermal conductivity and mechanical strength can be obtained.

The PAS resin composition according to the present embodiment can be subjected to various molding processes such as injection molding, compression molding, extrusion molding of composites, sheets, pipes, etc., pultrusion molding, blow molding, and transfer molding, but is particularly suitable for mold release. It also has excellent properties, making it suitable for injection molding applications. When molding is performed by injection molding, various molding conditions are not particularly limited, and molding can be performed by a general method. For example, in the injection molding machine, the resin temperature is in a temperature range above the melting point of the PAS resin (A), preferably in a temperature range above the melting point +10°C, more preferably in a temperature range from melting point +10°C to melting point +100°C, even more preferably After going through the process of melting the PAS resin composition at a temperature range of melting point +20 to +50° C., the resin composition may be injected into a mold through the resin discharge port and molded. At this time, the mold temperature may be set within a known temperature range, for example, room temperature (23°C) to 300°C, preferably 130 to 190°C.

The method for manufacturing a molded article according to the present embodiment may include a step of subjecting the molded article to an annealing treatment. The optimum conditions for the annealing treatment are selected depending on the purpose or shape of the molded product, but the annealing temperature is in a temperature range equal to or higher than the glass transition temperature of the PAS resin (A), preferably in a temperature range equal to or higher than the glass transition temperature +10°C. The temperature range is more preferably 30° C. or higher than the glass transition temperature. On the other hand, it is preferably in a range of 260°C or less, more preferably in a range of 240°C or less. Although the annealing time is not particularly limited, it is preferably in a range of 0.5 hours or more, and more preferably in a range of 1 hour or more. On the other hand, the duration is preferably 10 hours or less, and more preferably 8 hours or less. This range is preferable because not only the distortion of the resulting molded product is reduced and the crystallinity of the resin is improved, but also the thermal conductivity, mechanical properties, and fuel barrier properties are further improved. Although the annealing treatment may be performed in air, it is preferably performed in an inert gas such as nitrogen gas.

The PAS resin molded product according to this embodiment is characterized by excellent thermal conductivity and sliding properties, and is therefore particularly suitable for sliding parts. Specifically, it can be suitably used for sliding parts such as gears, bearings, cages, robot arms, etc. Further, the molded product of the present disclosure is not limited to a sliding component, but can also be a regular resin molded product such as the following. For example, protection and support members for box-shaped electric/electronic component integrated modules, multiple individual semiconductors or modules, sensors, LED lamps, connectors, sockets, resistors, relay cases, 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, terminal blocks, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, Electrical and electronic parts such as parabolic antennas and computer-related parts; VTR parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio, laser discs, compact discs, DVD discs, and Blu-ray discs. Household and office electrical appliances, such as audio/video equipment parts such as disks, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, and plumbing equipment parts such as water heaters, bath water quantity and temperature sensors, etc. Product parts: Office computer-related parts, telephone-related parts, facsimile-related parts, copying machine-related parts, cleaning jigs, motor parts, lighters, typewriters, etc.Machine-related parts: microscopes, binoculars, cameras, watches Optical equipment and precision machinery related parts such as alternator terminals, alternator connectors, brush holders, slip rings, IC regulators, potentiometer bases for light dimmers, relay blocks, inhibitor switches, various valves such as exhaust gas valves, and fuel related parts.・Various exhaust and intake system pipes, air intake nozzle snorkel, intake manifold, engine cooling water joint, carburetor main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crank Shaft position sensor, temperature sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, dust distributor, Starter switches, ignition coils and their bobbins, motor insulators, motor rotors, motor cores, starter relays, transmission wire harnesses, window washer nozzles, air conditioner panel switch boards, fuel-related electromagnetic valve coils, fuse connectors, horn terminals, electrical equipment Automotive and vehicle related parts include insulating plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition cases, etc., and can also be applied to various other uses. .

The present invention will be explained below using Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, hereinafter, unless otherwise specified, "%" and "part" are based on mass.

<Examples 1 to 7 and Comparative Examples 1 to 7>
Each material was blended according to the composition components and blending amounts listed in Table 1. After that, these compounded materials were put into a vented twin-screw extruder "TEX-30α (product name)" manufactured by Japan Steel Works, Ltd., and the resin component discharge rate was 30 kg/hr, the screw rotation speed was 200 rpm, and the resin temperature was set at 320°C. Pellets of the resin composition were obtained by melt-kneading. Glass fibers and carbon fibers were fed from a side feeder (S/T ratio 0.5), and other materials were uniformly mixed in advance in a tumbler and fed from a top feeder. After drying the obtained resin composition pellets in a gear oven at 140° C. for 2 hours, various test pieces were prepared by injection molding, and the following tests were conducted.

(1) Measurement of tensile properties The obtained pellets were supplied to a Sumitomo Heavy Industries injection molding machine (SE-75D-HP) whose cylinder temperature was set at 310°C, and molded into ISO Type 1A dumbbell pieces whose mold temperature was controlled at 140°C. Injection molding was performed using a molding die to obtain an ISO Type-A dumbbell piece. Note that the resin was injected from a single point gate to produce a test piece that did not include a weld portion. The tensile strength and tensile elongation of the obtained dumbbell pieces were measured using a measuring method based on ISO 527-1 and 2. The measurement results are shown in Tables 1 and 2.

(2) Measurement of Linear Thermal Expansion Coefficient The center part of the ISO Type 1A dumbbell piece prepared in the same manner as in (1) above was cut out into a rectangular parallelepiped with a length of 10 mm, a width of 10 mm, and a thickness of 4 mm, and a linear thermal expansion coefficient test piece was obtained. The coefficient of linear thermal expansion (1 /K) was measured. Using the obtained values, the linear thermal expansion coefficient ratio of MD/TD was calculated. The measurement results are shown in Tables 1 and 2.

(3) Abrasion test The obtained pellets were supplied to a Sumitomo Heavy Industries injection molding machine (SE-75D-HP) whose cylinder temperature was set at 310°C, and molded with an inner diameter of 20 mm and an outer diameter using a mold whose temperature was controlled to 140°C. A cylindrical test piece with a diameter of 25 mm and a height of 15.0 mm was obtained. Regarding this cylindrical test piece, the friction coefficient and specific wear amount [10 ⁻³ [mm ³ /(N×km)]] were measured under the following measurement conditions using a Suzuki type abrasion tester. The measurement results are shown in Tables 1 and 2.
Measurement conditions A:
Pressure: 150 KPa, rotation speed: 0.3 m/sec, measurement time: 60 minutes, temperature environment: 23°C, using the two test pieces obtained by molding with an injection molding machine, under the measurement conditions, the Suzuki A formula abrasion test was conducted.
Measurement condition B:
Pressure: 500 KPa, rotation speed: 0.3 m/sec, measurement time: 60 minutes, temperature environment: 23°C, using the two test pieces obtained by molding with an injection molding machine, the Suzuki A formula abrasion test was conducted.

(4) Measurement of thermal conductivity (hot disk method)
The obtained pellets were supplied to a Sumitomo Heavy Industries injection molding machine (SE-75D-HP) whose cylinder temperature was set to 310°C, and using a mold whose temperature was controlled to 140°C, an ISO D2 sheet (60 mm x 60 mm x thickness 2 mm) was obtained. Thermal conductivity was measured in the depth direction of the obtained test piece in accordance with ISO 22007-2 "Plastics - Determination of thermal conductivity and thermal diffusivity - Part 2: Transient planar heat source (hot disk) method". The rate (W/m·K) was measured. The measurement results are shown in Tables 1 and 2.

A-1: PPS resin (melt viscosity (V6) 150 Pa・s)
A-2: PPS resin (melt viscosity (V6) 250 Pa・s)
a-3: PPS resin (melt viscosity (V6) 35 Pa・s)
B-1: Graphite, scaly, average particle diameter (D ₅₀ ) 50 μm
b-2: Graphite, amorphous, average particle diameter (D ₅₀ ) 30 μm
C-1: PTFE resin D-1: Silicone resin F-1: Carbon fiber (chopped strand, fiber diameter 6 μm)
F-2: Carbon fiber (chopped strand, fiber diameter 6 μm)
F-3: Glass fiber (chopped strand, fiber diameter 10.5 μm)

Tables 1 and 2 show that the molded products obtained from the resin compositions of Examples have excellent tensile properties and thermal conductivity compared to Comparative Examples, and have reduced wear coefficients and specific wear amounts, and have good sliding properties. It can be seen that it exhibits movement.

Claims

A polyarylene sulfide resin composition for sliding members comprising a polyarylene sulfide resin (A) and graphite (B),
The melt viscosity (V6) of the polyarylene sulfide resin (A) is 90 Pa·s or more and 350 Pa·s or less,
Graphite (B) is in the form of scales, and the amount of graphite (B) in 100 parts by mass of the resin composition is 5 to 50 parts by mass,
A polyarylene sulfide resin composition for a sliding member, characterized in that the ratio of MD/TD of linear expansion coefficient of the resin composition is 0.5 or more.
(However, the coefficient of linear expansion is determined by cutting out the central part of an ISO Type 1A dumbbell-shaped test piece into a rectangular parallelepiped with a length of 10 mm, width of 10 mm, and thickness of 4 mm, and a temperature range of 145 to 145 mm in accordance with ISO 11359-2. (Values measured at 155°C).
The polyarylene sulfide resin composition for sliding members according to claim 1, wherein the amount of polyarylene sulfide resin (A) blended in 100 parts by mass of the resin composition is 50 to 90 parts by mass.
The polyarylene sulfide resin composition for sliding members according to claim 1 or 2, which is a melt-kneaded product.
A molded article for a sliding member obtained by melt-molding the polyarylene sulfide resin composition for a sliding member according to any one of claims 1 to 3.
A sliding member made of the molded product according to claim 4.
A method for producing a polyarylene sulfide resin composition for sliding members, comprising a step of blending polyarylene sulfide resin (A) and graphite (B) and melting and kneading the mixture at a temperature range equal to or higher than the melting point of polyarylene sulfide resin (A). And,
The melt viscosity of the polyarylene sulfide resin (A) is 90 Pa·s or more and 350 Pa·s or less,
Graphite (B) is scaly,
A method for producing a polyarylene sulfide resin composition for a sliding member, characterized in that the resin composition has a linear expansion coefficient MD/TD ratio of 0.5 or more.
(However, the coefficient of linear expansion is determined by cutting out the central part of an ISO Type 1A dumbbell-shaped test piece into a rectangular parallelepiped with a length of 10 mm, width of 10 mm, and thickness of 4 mm, and a temperature range of 145 to 145 mm in accordance with ISO 11359-2. (Values measured at 155°C).
The method for producing a polyarylene sulfide resin composition for sliding members according to claim 6, wherein the amount of polyarylene sulfide resin (A) blended in 100 parts by mass of the resin composition is 50 to 90 parts by mass.
A method for producing a molded article for a sliding member, comprising the step of melt-molding the polyarylene sulfide resin composition according to any one of claims 1 to 3.
A method for producing a sliding member, which is obtained by melt-molding the polyarylene sulfide resin composition according to any one of claims 1 to 3.