Coated recycled material and method for producing same

Abstract

To provide a coated recycled material having little mold contamination during molding, and to provide a method for producing the same.　Provided is a method for producing a coated recycled material (Z) that includes: the preparation of a recycled material (z1) for articles that contains 100 mass parts of a polyarylene sulfide resin (P) and 1-20 mass parts of an elastomer (Q); and the coating of at least part of the surface of the recycled material (z1) by an antioxidant (A). The amount of antioxidant (A) applied during coating is 0.025-0.25 mass parts per mass part of the elastomer (Q) contained in the recycled material (z1).

Description

Recycled coated material and its manufacturing method

[0001] The present invention relates to a coated reclaimed material and a method for producing the same.

[0002] Toward the creation of a sustainable recycling-based society, technologies for recycling and utilizing plastic waste have been investigated (for example, Patent Document 1). Polyarylene sulfide resins have excellent heat resistance, mechanical properties, chemical resistance, dimensional stability, and flame retardancy, and are therefore widely used as materials for electrical and electronic equipment components, automobile components, chemical equipment components, etc. Therefore, recycling and utilizing materials containing polyarylene sulfide resins can help create a sustainable recycling-based society.

[0003] Japanese Patent Application Laid-Open No. 2022-103152

[0004] When recycling materials containing polyarylene sulfide resins, molded products and parts other than the molded products discarded during molding (hereinafter collectively referred to as "recycled products") are crushed and then, if necessary, re-pelletized and molded using the recycled material. However, the recycled material may have decomposed matrix polymers, deteriorated additives, and refined fillers due to shear during crushing the recycled product, thermal history due to having undergone one or more molding processes, and thermal history during the re-pelletization process. In such cases, changes in fluidity, crystallinity, polarity, etc. may occur compared to virgin materials that have not undergone molding processes. When such recycled materials are used alone or as mixed pellets with virgin materials for molding, mold deposits and mold fouling are more likely to occur during molding than when virgin materials are used alone. In particular, mold fouling is more likely to occur when the polyarylene sulfide resin contained in the recycled product contains an elastomer. Reducing the amount of recycled material used to prevent mold fouling means that only small amounts of recycled material can be effectively used. On the other hand, one method to prevent mold fouling is to supply the recycled material as a mixture with an antioxidant to the raw material supply section during molding. However, segregation of the recycled material and the antioxidant during the raw material supply process can cause the antioxidant to be unevenly distributed in the mixture, which can lead to uneven mold fouling.

[0005] An object of the present disclosure is to provide a coated recycled material that causes less mold contamination during molding, and a method for producing the same.

[0006] The present invention has the following aspects: <1> A method for producing a coated recycled material (Z), comprising: preparing a recycled material (z1) of an article containing 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q); and coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A); wherein, in the coating, the amount of the antioxidant (A) coated is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1). <2> A coated recycled material (Z) in which at least a portion of the surface of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) is coated with an antioxidant (A), and the amount of coating of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[0007] According to the present invention, it is possible to provide a coated recycled material that causes little mold contamination during molding, and a method for producing the same.

[0008] FIG. 1 is a schematic diagram of a molded body used in evaluating mold deposits, with the upper side being a top view and the lower side being a cross-sectional view.

[0009] An embodiment of the present disclosure will be described in detail below. However, the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect described in this disclosure can be combined with any other feature described in this disclosure. Furthermore, when multiple upper and lower limit values ​​are described for a specific parameter, any of these upper and lower limit values ​​can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limit values ​​of a numerical range described in this disclosure are numerical values ​​within that numerical range and may be replaced with numerical values ​​shown in the examples. The expression "X to Y" indicating a numerical range means "X or more and Y or less." If a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0010] [First embodiment: manufacturing method of coated recycled material (Z)] The manufacturing method according to this embodiment is a manufacturing method of coated recycled material (Z), and includes the steps of: (1) preparing a recycled material (z1) of an article containing 100 parts by mass of polyarylene sulfide resin (P) and 1 to 20 parts by mass of elastomer (Q); and (2) coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A); wherein the coating amount of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[0011] As mentioned above, recycled materials often have changes in fluidity, crystallinity, polarity, etc. compared to virgin materials. When recycled products contain elastomers, the changes in their physical properties tend to be particularly significant. Therefore, even if a known additive is used, it is difficult to predict its effect when it is added to recycled materials. In particular, depending on the type and amount of additive, it may cause mold deposits during molding, so additives to be added to recycled materials must be carefully selected.

[0012] Therefore, the present inventors considered using recycled materials that already contained antioxidants as recycled products in order to suppress mold deposits during recycling. However, the expected effect of suppressing mold fouling was not achieved. After further research, the present inventors discovered that by coating recycled materials with a predetermined amount of antioxidant, mold fouling can be suppressed when the resulting coated recycled materials are injection molded, leading to the completion of the present disclosure.

[0013] That is, in this embodiment, by coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) so that the coating amount of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1), it is possible to obtain a coated recycled material (Z) that causes little mold contamination during injection molding.

[0014] In this specification, "recycle" means that an article such as a molded body (a recycled article) is pulverized and recycled as a raw material for use in manufacturing a molded body, and "recycled material" means the recycled material. The recycled material may be a pulverized product of the recycled article, or may be pellets obtained by melting and kneading the pulverized product. Pelletized recycled material is sometimes called "recycled pellets." Articles such as molded articles that are recycled are materials (raw materials) for recycling, and are sometimes called "raw materials for recycling." In contrast, raw materials not used in manufacturing a molded body (raw materials that have not undergone a molding process) are called "virgin material," pellets of virgin material are called "virgin pellets," and virgin material of polyarylene sulfide resin is called "virgin polyarylene sulfide resin."

[0015] "Coated recycled material" refers to recycled material having at least a portion of its surface coated with a certain compound (here, antioxidant (A)). In this specification, "coated" means that at least a portion of the surface of the recycled material is covered with antioxidant (A), and can include the antioxidant (A) adhering and / or adhering to a portion of the surface of the recycled material, as well as the antioxidant (A) spreading in a layer to cover a portion of the surface. "Adhering and / or adhering" can include a state in which solid (e.g., powdery) antioxidant (A) is adhered by electrostatic force or the like, or a state in which part of the solid antioxidant (A) has melted, with the remaining part remaining solid, and the melted part adhering to the surface of the recycled material.

[0016] <Preparation Step> In the preparation step, a recycled material (z1) of an article is prepared, comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q). The "article" here refers to an article to be recycled (a recycled product), and may be a molded product or an article that was discharged after being retained in a cylinder for a long period of time during molding. Examples include defective products generated during the manufacturing process of molded products, non-product parts (e.g., runners, sprues, etc.) obtained during injection molding, unused products, and chunks of polyarylene sulfide resin material used as a purge during molding and then discharged. Preferably, the recycled material includes at least one selected from these. In one embodiment, the recycled molded product may be an injection-molded product.

[0017] (Polyarylene sulfide resin (P)) The polyarylene sulfide resin (P) may be a virgin polyarylene sulfide resin, or a recycled polyarylene sulfide resin that has been reused one or more times. In one embodiment, the polyarylene sulfide resin (P) preferably comprises a virgin polyarylene sulfide resin. By using an article containing virgin polyarylene sulfide resin as a raw material for recycling, it is possible to further reduce mold contamination during molding. In one embodiment, the polyarylene sulfide resin (P) preferably comprises a recycled polyarylene sulfide resin. By using an article containing recycled polyarylene sulfide resin as a raw material for recycling, it is easier to create a sustainable recycling-based society.

[0018] The polyarylene sulfide resin is a resin having a repeating unit represented by the following general formula (I): -(Ar-S)- (I) (where Ar represents an arylene group).

[0019] The arylene group is not particularly limited, but examples thereof include a p-phenylene group, an m-phenylene group, an o-phenylene group, a substituted phenylene group, a p,p'-diphenylene sulfone group, a p,p'-biphenylene group, a p,p'-diphenylene ether group, a p,p'-diphenylene carbonyl group, and a naphthalene group.

[0020] The polyarylene sulfide resin can be a homopolymer using the same repeating unit represented by the general formula (I) above, or a copolymer containing different repeating units. A preferred homopolymer has a p-phenylene group as the arylene group, that is, a p-phenylene sulfide group as the repeating unit. This is because homopolymers having a p-phenylene sulfide group as the repeating unit have extremely high heat resistance and exhibit high strength, high rigidity, and high dimensional stability over a wide temperature range. By using such homopolymers, molded articles with excellent physical properties can be obtained.

[0021] As the copolymer, a combination of two or more different arylene sulfide groups among the above-mentioned arylene group-containing arylene sulfide groups can be used. Among these, a combination containing a p-phenylene sulfide group and an m-phenylene sulfide group is preferred from the viewpoint of obtaining a molded product with high physical properties such as heat resistance, moldability, and mechanical properties. A polymer containing 70 to 100 mol% of p-phenylene sulfide groups is more preferred, and a polymer containing 80 to 100 mol% is even more preferred. The polyarylene sulfide resin containing phenylene sulfide groups is a polyphenylene sulfide resin (PPS resin).

[0022] Polyarylene sulfide resins are generally known to have a substantially linear molecular structure without branching or crosslinking, or a structure with branching or crosslinking, depending on the production method thereof. In one embodiment, from the viewpoint of improving the toughness of a molded article, it is more preferable that the polyarylene sulfide resin does not contain a structure with a crosslinking structure.

[0023] In one embodiment, the content of polyarylene sulfide resin (P) in recycled material (z1) is preferably 30 to 99% by mass, and more preferably 50 to 95% by mass, based on the total amount of recycled material (z1). In one embodiment, the total content of polyarylene sulfide resin (P) and elastomer (Q) in the resin components contained in recycled material (z1) is preferably 80 to 100% by mass, and more preferably 90 to 100% by mass, based on the total amount of resin components. In one embodiment, the resin components contained in recycled material (z1) may consist of polyarylene sulfide resin (P) and elastomer (Q).

[0024] (Elastomer (Q)) Examples of the elastomer (Q) include olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, and the like, which may be grafted. Preferably, the elastomer (Q) contains at least one selected from these, and may contain, for example, an olefin-based elastomer. Even when the recycled material (z1) contains an elastomer, mold contamination can be suppressed when molding the resulting coated recycled material (Z).

[0025] The elastomer (Q) may be an elastomer having a reactive functional group, such as an acid-modified elastomer modified with an acid or an acid anhydride, such as (meth)acrylic acid or maleic anhydride; an elastomer using a copolymerizable monomer having a glycidyl group or an epoxy group (glycidyl (meth)acrylate, etc.); or an epoxy-modified elastomer obtained by epoxidizing the unsaturated bond of an elastomer.

[0026] Examples of olefin-based elastomers include copolymers of α-olefins and copolymers of α-olefins and copolymerizable monomers. The α-olefin is preferably one or more selected from α-olefins having 2 to 13 carbon atoms (e.g., ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, etc.). Examples of copolymers of α-olefins and copolymerizable monomers include, but are not limited to, α-olefin-unsaturated carboxylic acid alkyl ester copolymers and olefin-based copolymers containing structural units derived from α-olefins and structural units derived from glycidyl esters of α,β-unsaturated acids. Examples of glycidyl esters of α,β-unsaturated acids include, but are not limited to, acrylic acid glycidyl esters, methacrylic acid glycidyl esters, and ethacrylic acid glycidyl esters. The olefin-based copolymer may further contain structural units derived from (meth)acrylic acid esters. Specific preferred examples of the olefin-based elastomer include ethylene propylene rubber (EPR), ethylene-glycidyl methacrylate copolymer (E-GMA), ethylene-glycidyl methacrylate-methyl acrylate copolymer (E-GMA-MA), etc. The olefin-based elastomer may be contained alone or in combination of two or more kinds.

[0027] Examples of styrene-based elastomers include block copolymers composed of a polymer block mainly composed of a vinyl aromatic compound such as styrene and a polymer block mainly composed of an unhydrogenated and / or hydrogenated conjugated diene compound. Specific preferred examples of styrene-based elastomers include styrene-butadiene rubber (SBR) and styrene-ethylene-butylene-styrene block copolymer (SEBS). Furthermore, the styrene-based elastomer may be a modified copolymer into which a functional group (epoxy group, carboxy group, acid anhydride group, etc.) has been introduced. Examples of modified copolymers include epoxidized styrene-diene copolymers in which the unsaturated bond of the diene has been epoxidized (e.g., epoxidized styrene-diene-styrene block copolymers or hydrogenated polymers thereof). The styrene-based elastomers may be used alone or in combination of two or more.

[0028] Examples of polyester-based elastomers include block copolymers having an aromatic polyester such as polyethylene terephthalate or polybutylene terephthalate as a hard segment and a polyether such as polyethylene glycol or polytetramethylene glycol, or an aliphatic polyester such as polyethylene adipate, polybutylene adipate or polycaprolactone as a soft segment. One type of polyester-based elastomer may be contained alone, or two or more types may be contained in combination.

[0029] When the elastomer (Q) has a reactive functional group, it can enhance the impact resistance and high- and low-temperature impact properties of virgin materials, impart toughness, and the like, but during recycling, mold deposits are more likely to occur and mold contamination is more likely to occur. However, according to the manufacturing method of the coated recycled material (Z) of this embodiment, even when the recycled material (z1) contains an elastomer (Q) having a reactive functional group, mold contamination during molding can be reduced. In one embodiment, the elastomer (Q) may have a reactive functional group. In this case, in the manufacturing method of the coated recycled material (Z), preparing the recycled material (z1) can include preparing the recycled material (z1) of an article containing the elastomer (Q) having a reactive functional group.

[0030] The term "reactive functional group" as used herein refers to a functional group capable of reacting with an end group of a polyarylene sulfide resin to form a chemical bond at the melting temperature of the resin. Examples of the reactive functional group include a glycidyl group, an epoxy group, a carboxy group, a hydroxyl group, an acid anhydride group, a salt of a carboxy group, a carboxylic acid ester group, an amide group, an amino group, an isocyanate group, an isothiocyanate group, an acetoxy group, a silanol group, an alkoxysilane group, an alkynyl group, an oxazoline group, a thiol group, and a sulfonic acid group. In one embodiment, the elastomer (Q) may include an olefin-based elastomer, a styrene-based elastomer, or a polyester-based elastomer containing one or more groups selected from the group consisting of a glycidyl group, an epoxy group, a carboxy group, a hydroxyl group, an acid anhydride group, a salt of a carboxy group, a carboxylic acid ester group, an amide group, an amino group, an isocyanate group, an isothiocyanate group, an acetoxy group, a silanol group, an alkoxysilane group, an alkynyl group, an oxazoline group, a thiol group, and a sulfonic acid group.

[0031] In one embodiment, the elastomer (Q) may comprise one or more selected from an olefin-based elastomer comprising structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid, and a styrene-based elastomer comprising an epoxidized styrene-diene copolymer in which the unsaturated bond of the diene has been epoxidized. In one embodiment, the elastomer (Q) may comprise an elastomer (Q) comprising structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid. In this case, in the method for producing the coated recycled material (Z), preparing the recycled material (z1) may comprise preparing the recycled material (z1) of an article comprising the elastomer (Q) comprising structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid.

[0032] In one embodiment, when the elastomer has a reactive functional group, the content of the reactive functional group may be 0.1 to 10 mass %, or may be 0.5 to 8 mass %, of the total amount of the elastomer. The content of the reactive functional group can be calculated from the manufacturer's catalog value of the copolymer composition and the molecular weight of the functional group.

[0033] The content of the elastomer (Q) in the recycled material (z1) is 1 to 20 parts by mass, preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass, and even more preferably 3 to 8.5 parts by mass, per 100 parts by mass of the polyarylene sulfide resin (P). In one embodiment, the content of the elastomer (Q) in the pulverized material (X) may be 6.2 parts by mass per 100 parts by mass of the polyarylene sulfide resin (P). In all aspects, these values ​​may be combined to form the upper or lower limit of a numerical range. The elastomer content may be the value in the manufacturer's catalog for the article. The elastomer content may also be measured by thermogravimetry.

[0034] In one embodiment, the recycled material (z1) may contain 1 to 20% by weight, 2 to 18% by weight, or 3 to 16% by weight of the elastomer having a reactive functional group, based on the total amount of the recycled material (z1).

[0035] (Other Components) In addition to the polyarylene sulfide resin (P) and elastomer (Q), the recycled material (z1) may contain other components contained in the recycled molded article. Examples of other components that the recycled material (z1) may contain include organic or inorganic fillers, and other additives that are generally added to thermoplastic resins (e.g., flame retardants, colorants such as dyes and pigments, stabilizers such as UV absorbers, lubricants, crystallization accelerators, crystal nucleating agents, etc.).

[0036] Examples of organic or inorganic fillers include fibrous fillers such as glass fibers, carbon fibers, zinc oxide fibers, titanium oxide fibers, wollastonite, silica fibers, silica-alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, stainless steel fibers, aluminum fibers, titanium fibers, copper fibers, brass fibers, polyamides, high molecular weight polyethylene, aramids, fluororesins, polyester resins, and acrylic resins, and other high-melting point organic fibrous substances; carbon black, graphite, silica, quartz powder, glass beads, Examples of fillers include milled glass fiber, glass balloons, glass powder, talc (granular), silicates such as calcium silicate, aluminum silicate, and diatomaceous earth, metal oxides such as iron oxide, titanium oxide, zinc oxide, and granular alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and powdery and granular fillers such as silicon carbide, silicon nitride, boron nitride, and various metal powders; and plate-like fillers such as mica, glass flakes, talc (plate-like), mica, kaolin, clay, alumina (plate-like), and various metal foils. In terms of mechanical strength, heat resistance, etc., it is preferable to contain an inorganic filler.

[0037] The content of the organic or inorganic filler in the recycled material (z1) is preferably 10 to 70 mass %, more preferably 15 to 65 mass %, and even more preferably 20 to 60 mass %.

[0038] The recycled material (z1) may or may not contain an antioxidant. According to the production method of this embodiment, in either case, a coated recycled material (Z) can be obtained that causes less mold contamination during molding. When the recycled material (z1) contains an antioxidant, the antioxidant may be the same type as the antioxidant (A), or a different type. When the recycled material (z1) contains an antioxidant, the content thereof may be, for example, 0.05 to 2.0% by mass, 0.1 to 1.0% by mass, or 0.1 to 0.5% by mass, relative to the total amount (100% by mass) of the recycled material (z1).

[0039] (Recycled Material (z1)) As described above, the recycled material (z1) is a material obtained by pulverizing the above-mentioned article (recycled product) containing a predetermined amount of the polyarylene sulfide resin (P) and the elastomer (Q) and regenerating it as a raw material for use in producing a molded product. The recycled material (z1) may be a pulverized product of the recycled product, or may be pellets obtained by melt-kneading the pulverized product.

[0040] When the recycled material (z1) is a pulverized material, the average particle diameter of the pulverized material is preferably 0.3 to 20 mm, more preferably 0.4 to 15 mm, even more preferably 1 to 10 mm, even more preferably 1 to 5 mm, and particularly preferably 1 to 3 mm, from the viewpoint of reducing interference with the screw and / or torque of the extruder when producing recycled pellets. The average particle diameter of the pulverized material is the volume-based cumulative 50% diameter (D50) measured by laser diffraction scattering. The method for pulverizing the article is not limited and can be carried out by known methods, for example, using a jet mill, roller mill, high-speed rotary pulverizer, container-driven mill, etc. The preparation step may, if necessary, include classifying the pulverized material by sieving or the like.

[0041] When the recycled material (z1) is in the form of pellets, the shape of the pellets is not particularly limited and can be any shape, such as cylindrical (approximately cylindrical), spherical, or the like. In one embodiment, the method for producing the coated recycled material (Z) may include preparing the recycled material (z1) by melt-kneading the pulverized material of the above-mentioned article to prepare a pellet-shaped recycled material (z1). Preparing the pellet-shaped recycled material (z1) may include, for example, melt-kneading and extruding the pulverized material using a conventional melt-kneading device such as a single-screw or twin-screw extruder, and cutting it into pellets. The melt-kneading temperature is a temperature equal to or higher than the melting point of the polyarylene sulfide resin (P) contained in the recycled material (z1), typically 280 to 360°C, preferably 290 to 350°C.

[0042] The melt viscosity of the recycled material (z1) is not limited as long as it does not impair the effects of the present disclosure, and is preferably 310°C and a shear rate of 1200 sec. －１ The melt viscosity may be 10 to 1000 Pa·s, or 30 to 700 Pa·s, for example, using a known capillary rheometer, using a 1 mmφ×20 mmL flat die as a capillary, at a barrel temperature of 310° C. and a shear rate of 1000 sec －１ It can be measured by

[0043] In the coating step, at least a portion of the surface of the recycled material (z1) is coated with an antioxidant (A). The amount of the antioxidant (A) coated is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[0044] (Antioxidant (A)) Examples of the antioxidant (A) include phenol-based antioxidants, phosphorus-based antioxidants, and thioether-based antioxidants, and the antioxidant (A) preferably contains one or more selected from the group consisting of these, and more preferably contains a phenol-based antioxidant. The antioxidant (A) may be used alone or in combination of two or more.

[0045] Examples of phenolic antioxidants include compounds having one or more alkylphenol groups in their molecular structure. Preferred phenolic antioxidants are compounds having a phenyl group substituted with a hydroxyl group (—OH) and a tert-butyl group. Among these, compounds having two or more tert-butyl groups per phenolic hydroxyl group are more preferred. Specific examples of phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, stearyl-(3,5-dimethyl-4-hydroxybenzyl)thioglycolate, stearyl-β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate, distearyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, and distearyl(4-hydroxy-3-methyl-5-tert-butyl)benzyl. malonate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butylic acid]glycol ester, 4,4'-butylidenebis(6-tert-butyl-m-cresol), 1,1,3- Tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris[(3,5-di-te tert-butyl-4-hydroxyphenyl)propionyloxyethyl] isocyanurate, 2-octylthio-4,6-di(4-hydroxy-3,5-di-tert-butyl)phenoxy-1,3,5-triazine, 4,4'-thiobis(6-tert-butyl-m-cresol), triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexyldiol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis-octylthio-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-tert-butyl Examples of suitable phenolic antioxidants include isooctyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 2,4-bis[(octylthio)methyl]-o-cresol. Phenolic antioxidants may be used alone or in combination of two or more.

[0046] Examples of phosphorus-based antioxidants include tetrakis(2,4-di-tert-butylphenyl)-4,4'-bisphenylene phosphonite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4-di-butylphenyl)pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, 4,4'-[bis(2,4-di-tert-butyl-5-methylphenoxy)-phosphino]biphenyl, tris(nonylphenyl)phosphite, and distearylpentaerythritol diphosphat. Examples of the phosphorus-based antioxidant include phosphate, triphenyl phosphite, diphenyl alkyl phosphite, tridecyl phosphite, trioctyl phosphite, cyclic neopentane tetrale-bis(octadecyl phosphite), 3,5-di-butyl-4-hydroxybenzyl phosphonate diethyl ester, triphenyl phosphine, tridodecyl phosphine, tripropyl phosphine, trioctyl phosphine, tetraalkyl phosphonium halides, tetraalkyl phosphonium sulfonate chlorides, bis(4-tert-butylphenyl) phosphate sodium salt, etc. One type of phosphorus-based antioxidant may be used alone, or two or more types may be used in combination.

[0047] The thioether antioxidants include compounds having at least one thioether bond in their molecular structure. Specific examples of the thioether antioxidants include tetrakis[methylene-3-(dodecylthio)propionate]methane, dilauryl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate. The thioether antioxidants may be used alone or in combination of two or more.

[0048] The blending amount (coating amount) of the antioxidant (A) is 0.025 to 0.25 parts by mass, preferably 0.026 to 0.20 parts by mass, more preferably 0.027 to 0.15 parts by mass, even more preferably 0.028 to 0.10 parts by mass, and particularly preferably 0.030 to 0.085 parts by mass, per part by mass of the elastomer (Q) contained in the recycled material (z1). In one embodiment, the blending amount (coating amount) of the antioxidant (A) may be 0.05 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1). In all aspects, these numerical values ​​may be combined to form the upper or lower limit of the above numerical range.

[0049] The coating preferably includes the following coating method (i) or (ii): (i) a method of contacting the recycled material (z1) with a solid or liquid antioxidant (A) at a temperature equal to or higher than the melting point of the antioxidant (A); or (ii) a method of contacting the recycled material (z1) with a liquid antioxidant (A).

[0050] (Coating Method (i)) In one embodiment, the coating preferably includes (i) contacting the recycled material (z1) with a solid or liquid antioxidant (A) at a temperature equal to or higher than the melting point of the antioxidant (A). In one embodiment, the coating is preferably a method of contacting the recycled material (z1) with a solid or liquid antioxidant (A) at a temperature equal to or higher than the melting point of the antioxidant (A) and equal to or lower than the melting point (Tm1) (°C) of the recycled material (z1).

[0051] In this disclosure, the melting point of the antioxidant (A) is a value measured according to the DSC method (method described in JIS K 7121). The melting point of the recycled material (z1) is the melting point Tm1 measured with a differential scanning calorimeter, which is the peak top temperature of the endothermic peak observed in the first run when heated from room temperature at a temperature increase rate of 10°C / min (first run) according to the method based on JIS K 7121.

[0052] In one embodiment, from the viewpoint of facilitating coating, the melting point of the antioxidant (A) is preferably 50 to 135° C., more preferably 55 to 135° C., even more preferably 60 to 130° C., and most preferably 70 to 125° C. Examples of the melting points of the antioxidant (A) include triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (76 to 79° C.) and tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, which have melting points of 110 to 125° C.

[0053] In the coating method (i), the temperature at which the recycled material (z1) is brought into contact with the antioxidant (A) may be, for example, 80 to 160° C. or 100 to 140° C. The contact time is not limited and may be, for example, 5 minutes or more, or 3 to 8 hours.

[0054] The contacting is usually carried out by mixing the recycled material (z1) and the antioxidant (A) using a known stirrer, etc. For example, the recycled material (z1) and the antioxidant (A) can be contacted with each other in a known dryer such as an air circulation dryer, while heating or using residual heat after heating, preferably while stirring.

[0055] Generally, when producing a molded product using resin pellets, a step of drying the raw material resin pellets is often included. In one embodiment, the coating step can be performed by coating method (i) during the step of drying the pellet-shaped recycled material (z1) or immediately after the drying step, in a state where the temperature of the recycled material (z1) is equal to or higher than the melting point (°C) of the antioxidant (A). By performing the coating step during the step of drying the pellet-shaped recycled material (z1) (or immediately after the drying step), the heat from the drying step can be effectively utilized to coat the recycled material.

[0056] The antioxidant (A) used in the coating method (i) may be solid or liquid at room temperature (25°C), and is preferably solid. Even if the antioxidant (A) is solid, it is brought into contact with the recycled material (z1) at a temperature equal to or higher than the melting point of the antioxidant (A), and therefore the antioxidant (A) melts and can spread over at least a portion of the surface of the recycled material (z1). As a result, at least a portion of the surface of the recycled material (z1) can be coated.

[0057] In one embodiment, the antioxidant (A) is preferably in powder, flake, or granular form. That is, in one embodiment, the coating preferably includes contacting the recycled material (z1) with the powder, flake, or granular antioxidant (A) at a temperature equal to or higher than the melting point of the antioxidant (A). In one embodiment, the powder antioxidant (A) may be formed of powder-like fine particles. In one embodiment, the flaky antioxidant (A) may be formed of plate-like fine particles. In one embodiment, the granular antioxidant (A) may be formed of a plurality of fine particles gathering to form a single particle.

[0058] (Coating method (ii)) In another embodiment, the coating step preferably includes (ii) contacting the recycled material (z1) with a liquid antioxidant (A). The liquid antioxidant (A) may be an antioxidant (A) that is liquid at room temperature (25°C), or may be a liquid antioxidant (A) obtained by heating an antioxidant (A) that is solid at room temperature (25°C) to a temperature equal to or higher than its melting point. Alternatively, the liquid antioxidant (A) may be a liquid antioxidant (A) obtained by dissolving an antioxidant (A) that is solid at room temperature (25°C) in a solvent. By using a liquid antioxidant (A), it is not necessary to heat the recycled material (z1) in the coating step.

[0059] The contact method is not limited, and examples thereof include a method of applying the liquid antioxidant (A) to the surface of the recycled material (z1) by coating, spraying, or the like, and a method of stirring and mixing the recycled material (z1) and the liquid antioxidant (A).

[0060] After the coating step, the obtained coated recycled material (Z) is preferably cooled to room temperature to 80°C, more preferably room temperature to 40°C, to fix the surface coating layer (or coated area). Fixing the coating layer allows the compound to remain uniformly dispersed, improving stable releasability. The cooling method is not limited, and may be left to cool, blowing air, or the like.

[0061] [Second embodiment: Coated recycled material (Z)] The coated recycled material (Z) according to this embodiment is an article comprising 100 parts by mass of polyarylene sulfide resin (P) and 1 to 20 parts by mass of elastomer (Q), and at least a portion of the surface of recycled material (z1) is coated with antioxidant (A), and the coating amount of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[0062] Since the amount of antioxidant (A) coated on the recycled material (z1) is 0.025 to 0.25 parts by mass per part by mass of elastomer (Q), it is possible to produce a coated recycled material (Z) that causes less mold contamination during molding. The types and contents of the polyarylene sulfide resin (P), elastomer (Q), recycled material (z1), and antioxidant (A), as well as the method for producing the coated recycled material (Z), are as described above.

[0063] The coating amount of the antioxidant (A) on the recycled material (z1) is preferably 0.026 to 0.20 parts by mass, more preferably 0.027 to 0.15 parts by mass, even more preferably 0.028 to 0.10 parts by mass, and particularly preferably 0.030 to 0.085 parts by mass, per 100 parts by mass of the elastomer (Q). In one embodiment, the coating amount of the antioxidant (A) may be 0.05 parts by mass per 100 parts by mass of the elastomer (Q) contained in the recycled material (z1). In all aspects, these values ​​may be combined to form the upper or lower limit of the above-mentioned numerical range. The coating amount of the antioxidant (A) can be measured, for example, by NMR or the like.

[0064] The content of the elastomer (Q) is 1 to 20 parts by mass, preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass, and even more preferably 3 to 8.5 parts by mass, per 100 parts by mass of the polyarylene sulfide resin (P). In one embodiment, the content of the elastomer (Q) may be 6.2 parts by mass per 100 parts by mass of the polyarylene sulfide resin (P). In all aspects, these values ​​may be combined to form the upper or lower limit of the above-mentioned numerical range. The content of the elastomer (Q) in the coated recycled material (Z) can be measured, for example, by thermogravimetry.

[0065] In one embodiment, the elastomer (Q) may have a reactive functional group. In one embodiment, the elastomer (Q) may include an elastomer (Q) containing structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid. The reactive functional group and the like are also as described above. The other descriptions regarding the elastomer (Q) in the first embodiment also apply here.

[0066] In one embodiment, the melt viscosity of the coated recycling material (Z) is not limited as long as it does not impair the effects of the present disclosure, and is preferably 310°C and a shear rate of 1200 sec. －１ The melt viscosity measured by the method may be 10 to 1000 Pa·s, or 30 to 700 Pa·s. The method for measuring the melt viscosity is as described in the section on recycled material (z1).

[0067] The coated recycled material (Z) may contain other components that can generally be blended into thermoplastic resins. Examples of other components include organic or inorganic fillers and other additives that are generally added to thermoplastic resins (e.g., flame retardants, colorants such as dyes and pigments, stabilizers such as UV absorbers, lubricants, crystallization accelerators, crystal nucleating agents, etc.). Examples of organic or inorganic fillers include those exemplified as organic or inorganic fillers that can be contained in the recycled material (z1).

[0068] The method for producing the coated recycled material (Z) is as described above. The form of the coated recycled material (Z) is not limited, and it may be in any desired form such as powder, flakes, pellets, etc.

[0069] In one embodiment, the coated recycled material (Z) has a mold deposit of preferably 0 to 45 μg, more preferably 0 to 40 μg, even more preferably 0 to 35 μg, and particularly preferably 0 to 30 μg, measured by the following method. <Measurement method> Using a nested mold with a detachable vent portion and cavity portion, the molded article shown in FIG. 1 is continuously molded for 4 hours (1,000 times) using an injection molding machine under the following conditions. Before and after continuous molding, the total weight of the vent portion and cavity portion removed from the mold is measured, and the total weight change of the vent portion and cavity portion before and after continuous molding is taken as the weight of the deposit on the mold. <Injection molding conditions> Cylinder temperature: 340°C Injection time: 2 seconds Cooling time: 10 seconds Mold temperature: 140°C

[0070] (Uses) The coated recycled material (Z) can suppress mold contamination during molding, and therefore can be suitably used as a resin composition for injection molding or a resin composition for extrusion molding. The coated recycled material (Z) can be mixed with other thermoplastic resins as needed and used as a molding material. Examples of other thermoplastic resins include virgin polyarylene sulfide resins, and preferably virgin polyarylene sulfide resins or virgin polyarylene sulfide resin compositions.

[0071] [Third embodiment: manufacturing method of coated recycled material-virgin material mixed resin composition (W)] The manufacturing method according to this embodiment is a manufacturing method of coated recycled material-virgin material mixed resin composition (W), and includes mixing the coated recycled material (Z) manufactured by the manufacturing method of the coated recycled material (Z) described above with virgin polyarylene sulfide resin or a composition (V) thereof. By mixing with virgin polyarylene sulfide resin or a composition (V) thereof, the excellent physical properties of the polyarylene sulfide resin can be reinforced. The manufacturing method of the coated recycled material (Z) and the coated recycled material (Z) themselves are as described above, and therefore a description thereof will be omitted here.

[0072] As described above, virgin polyarylene sulfide resin is a virgin polyarylene sulfide resin. Examples of virgin polyarylene sulfide resin compositions include compositions containing virgin polyarylene sulfide resin and, if necessary, other components. Examples of polyarylene sulfide resins containing virgin polyarylene sulfide resins or their composition (V) include those described for the coated recycled material (Z) above. From the viewpoint of quality control, it is preferable that the composition be the same as that of the polyarylene sulfide resin in the coated recycled material (Z). Examples of other components include compounds similar to the other components that may be contained in the coated recycled material (Z), elastomers, antioxidants, etc. When the virgin polyarylene sulfide resin or its composition (V) is a composition, it is preferable that the composition be the same as that of the coated recycled material (Z) from the viewpoint of quality control, etc. (for example, the type and content of additives are the same).

[0073] The amount of coated recycled material (Z) blended is preferably 50% by mass or more, more preferably 50 to 99.99% by mass, and even more preferably 60 to 100% by mass, relative to the total amount (100% by mass) of the coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V), in order to increase the amount of recycled material used. Even if the blending amount of coated recycled material (Z) is increased, a coated recycled material-virgin material mixed resin composition (W) with little mold contamination during molding can be obtained.

[0074] The mixing method is not limited, and the coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V) may be dry blended, melt-kneaded using a conventional melt-kneading device such as a single-screw or twin-screw extruder, or mixed in the hopper (material supply member) of an injection molding machine. The resulting recycled material-virgin material mixed resin composition (W) can be processed into a desired form such as powder, flakes, or pellets.

[0075] [Fourth embodiment: Coated recycled material-virgin material mixed resin composition (W)] The coated recycled material-virgin material mixed resin composition (W) according to this embodiment contains the coated recycled material (Z) described above and a virgin polyarylene sulfide resin or composition thereof (V). By including the virgin polyarylene sulfide resin or composition thereof (V), the excellent physical properties of the polyarylene sulfide resin can be reinforced. The coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V) are as described in the section on the manufacturing method of the recycled material-virgin material mixed resin composition (W) above.

[0076] In order to increase the amount of recycled material used, the content of the coated recycled material (Z) is preferably 50% by mass or more, more preferably 50 to 99.99% by mass, and even more preferably 60 to 100% by mass, based on the total amount of the coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V). The coated recycled material-virgin material mixed resin composition (W) causes little mold contamination during molding, even when the coated recycled material (Z) content is high.

[0077] In one embodiment, the total content of the coated recycled material (Z) and virgin polyarylene sulfide resin or a composition thereof is preferably 80 to 100 mass%, more preferably 90 to 100 mass%, and even more preferably 95 to 100 mass%, relative to the total amount (100 mass%) of resin components contained in the coated recycled material-virgin material mixed resin composition (W), and may be 100 mass%.

[0078] In one embodiment, the melt viscosity of the coated recycled material-virgin material mixed resin composition (W) is not limited as long as it does not impair the effects of the present disclosure, and is preferably 310°C and a shear rate of 1200 sec. －１ The melt viscosity measured by the method may be 10 to 1000 Pa·s, or 30 to 700 Pa·s. The method for measuring the melt viscosity is as described in the section on recycled material (z1).

[0079] The coated recycled material-virgin material mixed resin composition (W) may contain other components that can generally be blended into thermoplastic resins. Examples of other components include organic or inorganic fillers, and other additives that are generally added to thermoplastic resins (e.g., flame retardants, colorants such as dyes and pigments, stabilizers such as UV absorbers, lubricants, crystallization accelerators, crystal nucleating agents, etc.). Examples of organic or inorganic fillers include those exemplified as organic or inorganic fillers that may be contained in the recycled material (z1). The form of the coated recycled material-virgin material mixed resin composition (W) is not limited and may be in any desired form, such as powder, flakes, or pellets.

[0080] (Uses) The coated recycled material-virgin material mixed resin composition (W) can suppress mold contamination during molding, and can therefore be suitably used as a resin composition for injection molding or a resin composition for extrusion molding.

[0081] [Fifth embodiment: recycled molded product] The recycled molded product according to this embodiment is a molded product containing the coated recycled material (Z) described above. The manufacturing method of the recycled molded product is not limited, and the recycled molded product can be manufactured by using the coated recycled material (Z) together with other thermoplastic resins and additives as necessary, and performing known injection molding, profile / solidification extrusion processing, press molding, spinning processing, etc. The coated recycled material (Z) causes little mold contamination during molding, so the number of mold replacements can be reduced, and the productivity of recycled molded products can be improved.

[0082] [Sixth Embodiment: Method for Suppressing Mold Fouling] The method according to this embodiment is a method for suppressing mold fouling during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q), the method comprising: coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A), wherein the coating comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1). By coating at least a portion of the surface of the recycled material (z1) with a predetermined amount of antioxidant (A), mold fouling during molding can be suppressed.

[0083] Details of the polyarylene sulfide resin (P), the elastomer (Q), the antioxidant (A), and the recycled material (z1) are as described above.

[0084] In one embodiment, the coating step preferably includes contacting the recycled material (z1) with the antioxidant (A) in a powder, flake, or granular form at a temperature equal to or higher than the melting point of the antioxidant (A). The method for contacting the recycled material (z1) with the antioxidant (A) at a temperature equal to or higher than the melting point of the antioxidant (A) is as described above.

[0085] In another embodiment, the coating step preferably includes contacting the regenerant (z1) with a liquid antioxidant (A). The method for contacting the regenerant (z1) with the liquid antioxidant (A) is as described above.

[0086] In one embodiment, this method may be a method for suppressing mold fouling during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) having a reactive functional group.

[0087] In one embodiment, this method may be a method for suppressing mold fouling during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) comprising structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid.

[0088] [Seventh Embodiment: Use of Antioxidant (A)] This embodiment of the present invention relates to a method for suppressing mold fouling during molding of a recycled material (z1) for an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q). The method comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A). The coating comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1). By coating at least a portion of the surface of the recycled material (z1) with a predetermined amount of antioxidant (A), mold fouling during molding of the recycled material (z1) can be suppressed. Details of the polyarylene sulfide resin (P), elastomer (Q), antioxidant (A), and recycled material (z1) are as described above.

[0089] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below. [1] A method for producing a coated recycled material (Z), comprising: preparing a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q); and coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A), wherein the coating amount of the antioxidant (A) is 0.025 to 0.25 parts by mass per 1 part by mass of the elastomer (Q) contained in the recycled material (z1). [2] The production method according to [1], wherein preparing the recycled material (z1) comprises preparing a recycled material (z1) of an article comprising an elastomer (Q) having a reactive functional group. [3] The production method according to [1] or [2], wherein preparing the recycled material (z1) comprises preparing pellet-shaped recycled material (z1) obtained by melt-kneading a pulverized product of the article. [4] The manufacturing method according to any one of [1] to [3], wherein the coating step comprises contacting the recycled material (z1) with an antioxidant (A) containing one or more selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, and thioether-based antioxidants. [5] The manufacturing method according to any one of [1] to [4], wherein the coating step comprises contacting the recycled material (z1) with the antioxidant (A) in powder, flake, or granular form at a temperature equal to or higher than the melting point of the antioxidant (A). [6] The manufacturing method according to any one of [1] to [5], wherein the coating step comprises contacting the recycled material (z1) with the antioxidant (A) in liquid form. [7] A manufacturing method for a coated recycled material-virgin material mixed resin composition (W), comprising mixing the coated recycled material (Z) produced by the manufacturing method according to any one of [1] to [6] with a virgin polyarylene sulfide resin or a composition thereof (V).[8] A coated recycled material (Z), in which at least a portion of the surface of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) is coated with an antioxidant (A), and the amount of the antioxidant (A) coated is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1). [9] The coated recycled material (Z) according to [8], in which the elastomer (Q) has a reactive functional group.

[10] The coated recycled material (Z) according to [8] or [9], in which the elastomer (Q) comprises a structural unit derived from an α-olefin and a structural unit derived from a glycidyl ester of an α,β-unsaturated acid.

[11] A coated recycled material-virgin material mixed resin composition (W) comprising the coated recycled material (Z) according to any of [8] to

[10] and a virgin polyarylene sulfide resin or a composition thereof (V).

[12] The coated recycled material-virgin material mixed resin composition (W) according to

[11] , wherein the content of the coated recycled material (Z) is 50% by mass or more relative to the total amount of the coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V).

[13] A method for suppressing mold fouling during molding of a recycled material (z1) for an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q), the method comprising coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A), the coating comprising coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[14] The method according to

[13] , wherein the method is a method for suppressing mold fouling during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) having a reactive functional group.

[15] The method according to

[13] or

[14] , wherein the coating comprises contacting the recycled material (z1) with the antioxidant (A) in a powder, flake, or granular form at a temperature equal to or higher than the melting point of the antioxidant (A).

[16] The method according to either

[13] or

[14] , wherein the coating step comprises contacting the recycled material (z1) with a liquid antioxidant (A).

[17] Use of an antioxidant (A) for suppressing mold fouling during molding of a recycled material (z1) for an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q), the use comprising coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A), and the coating step comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

[0090] The present invention will be explained in more detail below by showing examples, but the interpretation of the present invention is not limited to these examples.

[0091] [Materials] (Recycled pellets (1): Recycled material of injection-molded products containing no antioxidants) Polyphenylene sulfide resin (PPS) (manufactured by Kureha Corporation, Fortron (registered trademark) KPS) 65% by mass, glass fiber (GF) 30% by mass, and elastomer (composition: E-GMA-MA (glycidyl methacrylate content: 3% by mass)) 4% by mass, the remainder other additives. An injection-molded product of resin composition A (but containing no antioxidants) was pulverized using a mechanical pulverizer to obtain a pulverized product having an average particle diameter D50 of 3 mm. The obtained pulverized product was placed in a twin-screw extruder with a cylinder temperature of 320 ° C. and melt-kneaded to obtain a pellet-shaped recycled material (recycled pellets (1)). The content ratio of each component in the recycled pellets (1) relative to 100 parts by mass of polyarylene sulfide resin is shown in Table 1 as "Composition of Resin Composition A".

[0092] (Recycled pellets (2): recycled material of injection-molded product containing antioxidant) Polyphenylene sulfide resin (PPS) (manufactured by Kureha Corporation, Fortron (registered trademark) KPS) 64.8% by mass, glass fiber (GF) 30% by mass, elastomer (composition: E-GMA-MA (glycidyl methacrylate content: 3% by mass)) 4% by mass, and antioxidant 0.2% by mass, the remainder was an injection-molded product of resin composition B containing other additives, was pulverized using a mechanical pulverizer to obtain a pulverized product having an average particle diameter D50 of 3 mm. The obtained pulverized product was put into a twin-screw extruder with a cylinder temperature of 320 ° C. and melt-kneaded to obtain a pellet-shaped recycled material (recycled pellets (2)). The content ratio of each component relative to 100 parts by mass of polyarylene sulfide resin in recycled pellets (2) is shown in Table 1 as "Composition of Resin Composition B".

[0093] (Antioxidant (A)) Tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, IRGANOX 1010 (product name), manufactured by BASF Japan Ltd., melting point: 110 to 125°C. The melting point of the antioxidant (A) was the value in the manufacturer's catalog.

[0094] [Example 1] 10 kg of recycled pellets (1) and 20 g of powdered antioxidant (A) (0.05 parts by mass per part by mass of the elastomer in the recycled pellets (1)) were placed in a metal container (30 cm × 60 cm × 15 cm), heated at 140°C for 3 hours in a blower dryer, and then cooled to room temperature. Thereafter, the mixture was stirred (dispersed) in a mixer to obtain coated recycled pellets (Z1).

[0095] Comparative Example 1 Regenerated pellet (1) was used as a sample.

[0096] Comparative Example 2 Regenerated pellet (2) was used as a sample.

[0097] Comparative Examples 3 and 4: 10 kg of recycled pellets (1) or (2) shown in Table 1 was placed in a metal container (30 cm x 60 cm x 15 cm) and dried in a fan dryer at 140°C for 3 hours, then cooled to room temperature. 20 g of powdered antioxidant (A) (0.05 parts by mass per part by mass of the elastomer in recycled pellets (1) or (2)) was added, followed by stirring (dispersion) in a mixer. Visual inspection of the pellet surfaces revealed no adhesion of antioxidant (A) to the pellet surfaces.

[0098] Reference Example 1 In Reference Example 1, virgin pellets of the polyarylene sulfide resin composition A (containing no antioxidant) were used.

[0099] Reference Example 2 In Reference Example 2, virgin pellets of the polyarylene sulfide resin composition B (containing an antioxidant) were used.

[0100] [Evaluation of Mold Deposits] A nested mold with detachable vent and cavity sections was used. Using each recycled pellet and the virgin pellets of the Reference Example, molded bodies having the dimensions and shape shown in Figure 1 were continuously molded for 4 hours (1,000 times) using the following injection molding machine and conditions. The total weight of the vent and cavity sections removed from the mold was measured before and after continuous molding. The change in the total weight of the vent and cavity sections before and after continuous molding was calculated as the weight (μg) of deposits on the mold. During injection molding, the hopper capacity amount was supplied into the hopper (i.e., a single supply amount without replenishment), and the MD deposit amount was measured for 4 hours after 60% by mass was consumed. The results are shown in Table 1. Injection molding machine: FANUC ROBOSHOT S2000i30A, Cylinder temperature: 340°C, Injection time: 2 seconds, Cooling time: 10 seconds, Mold temperature: 140°C

[0101]

[0102] As shown in Table 1, the amount of mold adhesion was 27 μg when the coated recycled pellets (Z1) of Example 1 were used. In contrast, the amount of mold adhesion was 69 μg when the recycled pellets (1) of Comparative Example 1, which were not coated with antioxidant (A), were used, and the amount of mold adhesion was 57 μg when the recycled pellets (2) of Comparative Example 2, which were not coated with antioxidant (A), were used. In Comparative Examples 3 and 4, in which powdered antioxidant (A) was mixed with recycled pellets (1) or (2) at room temperature, the amount of mold adhesion was 66 μg or 54 μg. The amount of mold adhesion was 51 μg when the virgin pellets of Reference Example 1 were used, and the amount of mold adhesion was 31 μg when the virgin pellets of Reference Example 2 were used.

[0103] The coated recycled pellets (Z1) of Example 1 resulted in less mold fouling than the virgin pellets of Reference Examples 1 and 2, and were able to reduce mold fouling by about 40% compared to the recycled pellets (1) of Comparative Example 1 that were not coated with antioxidant (A) (i.e., reduced mold fouling by about 60%). Furthermore, compared to the recycled pellets (2) of Comparative Example 2 that were not coated with antioxidant (A), they were able to reduce mold fouling by about 47% (i.e., reduced mold fouling by about 53%). In contrast, the recycled pellets (1) of Comparative Example 1 that were not coated with antioxidant (A) resulted in more mold fouling than the virgin pellets of Reference Example 1. The recycled pellets (2) of Comparative Example 2 that were not coated with antioxidant (A) resulted in more mold fouling than the virgin pellets of Reference Example 2, and also resulted in more mold fouling than the virgin pellets of Reference Example 1. These results show that recycled pellets cause worse mold fouling than virgin pellets, and that even when the recycled raw material contains an antioxidant, the effect of suppressing mold fouling when molding the resulting recycled material is low. Furthermore, as shown in Comparative Examples 3 and 4, even when antioxidant (A) is blended during molding, if it is not attached to the surface of recycled pellets (1) or (2), the antioxidant (A) segregates during molding, and the effect of suppressing mold fouling is not sufficiently achieved.

[0104] The method for producing a recycled polyarylene sulfide resin composition of this embodiment can suppress mold contamination during molding, and therefore has industrial applicability as a method for producing a resin composition for injection molding or a resin composition for extrusion molding.

Claims

1. A method for producing a coated recycled material (Z), comprising: preparing a recycled material (z1) of an article containing 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q); and coating at least a portion of the surface of the recycled material (z1) with an antioxidant (A); wherein, in the coating, the coating amount of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

2. The manufacturing method according to claim 1, wherein preparing the recycled material (z1) includes preparing a recycled material (z1) of an article comprising an elastomer (Q) having a reactive functional group.

3. The manufacturing method according to claim 1 or 2, wherein preparing the recycled material (z1) includes preparing a pellet-shaped recycled material (z1) obtained by melt-kneading the pulverized material of the article.

4. The method according to claim 1 or 2, wherein the coating step includes contacting the recycled material (z1) with an antioxidant (A) comprising one or more selected from the group consisting of a phenol-based antioxidant, a phosphorus-based antioxidant, and a thioether-based antioxidant.

5. The method according to claim 1 or 2, wherein the coating step includes contacting the recycled material (z1) with the antioxidant (A) in a powder, flake or granular form at a temperature equal to or higher than the melting point of the antioxidant (A).

6. The method according to claim 1 or 2, wherein the coating step includes contacting the regenerator (z1) with a liquid antioxidant (A).

7. A method for producing a coated recycled material-virgin material mixed resin composition (W), comprising mixing the coated recycled material (Z) produced by the method according to claim 1 or 2 with virgin polyarylene sulfide resin or a composition thereof (V).

8. A coated recycled material (Z) in which at least a portion of the surface of a recycled material (z1) of an article containing 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) is coated with an antioxidant (A), and the amount of coating of the antioxidant (A) is 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

9. The coating regenerator (Z) according to claim 8, wherein the elastomer (Q) has a reactive functional group.

10. The coated recycling material (Z) according to claim 8 or 9, wherein the elastomer (Q) contains a structural unit derived from an α-olefin and a structural unit derived from a glycidyl ester of an α,β-unsaturated acid.

11. A coated recycled material-virgin material mixed resin composition (W) comprising the coated recycled material (Z) according to claim 8 or 9 and a virgin polyarylene sulfide resin or a composition thereof (V).

12. The coated recycled material-virgin material mixed resin composition (W) according to claim 11, wherein the content of the coated recycled material (Z) is 50 mass% or more based on the total amount of the coated recycled material (Z) and the virgin polyarylene sulfide resin or composition thereof (V).

13. A method for suppressing mold contamination during molding of a recycled material (z1) of an article containing 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q), the method comprising: coating at least a portion of a surface of the recycled material (z1) with an antioxidant (A), wherein the coating comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

14. The method according to claim 13, which is a method for suppressing mold contamination during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q) having a reactive functional group.

15. The method according to claim 13 or 14, wherein the coating step includes contacting the regenerator (z1) with the antioxidant (A) in a powder, flake or granular form at a temperature equal to or higher than the melting point of the antioxidant (A).

16. The method of claim 13 or 14, wherein the coating step includes contacting the regenerant (z1) with a liquid antioxidant (A).

17. Use of an antioxidant (A) for suppressing mold fouling during molding of a recycled material (z1) of an article comprising 100 parts by mass of a polyarylene sulfide resin (P) and 1 to 20 parts by mass of an elastomer (Q), comprising coating at least a portion of a surface of the recycled material (z1) with the antioxidant (A), wherein the coating comprises coating at least a portion of the surface of the recycled material (z1) with the antioxidant (A) in an amount of 0.025 to 0.25 parts by mass per part by mass of the elastomer (Q) contained in the recycled material (z1).

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