WO2024204840A1 - Recycled polyarylene sulfide resin composition and method for producing same - Google Patents

Abstract

The present invention provides: a recycled polyarylene sulfide resin composition which exhibits excellent releasability from a mold; and a method for producing this recycled polyarylene sulfide resin composition.　This recycled polyarylene sulfide resin composition (Y) contains: 100 parts by mass of a material (X) for recycling, which is a ground product of articles containing a polyarylene sulfide resin; and a total of 0.1 part by mass to 3.0 parts by mass of a compound (A) that contains one or more compounds selected from among (A-1) an olefin resin having a melt viscosity of 0.1 Pa∙s to 8.0 Pa∙s at 140°C, (A-2) a fatty acid derivative and (A-3) a silicone compound.

Description

Recycled polyarylene sulfide resin composition and its manufacturing method

The present invention relates to a recycled polyarylene sulfide resin composition and a method for producing the same.

In order to build a sustainable recycling-based society, technologies for recycling and utilizing plastic waste are being considered (for example, Patent Document 1).
Polyarylene sulfide resins are excellent in heat resistance, mechanical properties, chemical resistance, dimensional stability, and flame retardancy, and are therefore widely used in electrical and electronic equipment component materials, automotive component materials, chemical equipment component materials, etc. Therefore, recycling and utilizing materials containing polyarylene sulfide resins can help build a sustainable recycling-oriented society.

JP 2022-103152 A

Incidentally, when molding a resin material containing a polyarylene sulfide resin, a method of injection molding or extrusion molding a pellet-shaped resin material (hereinafter also simply referred to as "pellets") can generally be adopted. In addition, as a method for obtaining pellets, for example, a method of mixing a polyarylene sulfide resin with other components such as an inorganic filler as necessary, melt-kneading and extruding the mixture with a single-screw or twin-screw extruder to obtain pellets can be adopted.
When recycling materials containing polyarylene sulfide resin, molded products or items discharged after a long time residence in a cylinder during molding (hereinafter collectively referred to as "recycled products") are crushed and then re-pelletized to form recycled pellets (hereinafter also referred to as "repellet"). However, the recycled pellets may have decomposition of the matrix polymer, deterioration of additives, and fineness of fillers due to shearing when crushing the recycled products and heat history due to having been through one or more molding processes. In that case, there may be changes in fluidity, crystallinity, polarity, etc. compared to virgin materials that have not been through a molding process. When such recycled pellets are used alone or as mixed pellets with virgin materials for molding, the releasability from the mold may be worse than when only virgin materials are used. If the amount of recycled pellets used is reduced to prevent the deterioration of releasability, only a small amount of recycled material can be effectively used. On the other hand, there is a method for improving the releasability by applying a release agent to the mold used during molding. However, when the mixing ratio of recycled pellets is high or when injection molding a molded product with a large contact area with the mold, the release agent must be applied to the mold many times, which can result in a decrease in work efficiency.
Furthermore, when additional components are added to the recycled material, depending on the type and amount of the components, mold deposits (MD) are likely to occur during molding of the recycled pellets, which may result in mold contamination.

The objective of the present invention is to provide a recycled polyarylene sulfide resin composition that has excellent releasability from a mold and a method for producing the same. More specifically, the objective of the present invention is to provide a recycled polyarylene sulfide resin composition that has excellent releasability from a mold while suppressing the occurrence of mold deposits during molding and a method for producing the same.

The present invention has the following aspects.
[1] A recycled polyarylene sulfide resin composition (Y) comprising: 100 parts by mass of recycled material (X), which is a pulverized product of an article containing a polyarylene sulfide resin; and a total of 0.1 to 3.0 parts by mass of compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound.
[1a] A recycled polyarylene sulfide resin composition (Y) comprising 100 parts by mass of a recycled material (X) containing a polyarylene sulfide resin, and a total of 0.1 to 3.0 parts by mass of a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound.
[2] The recycled polyarylene sulfide resin composition (Y) according to [1] or [1a], wherein the recycled material (X) contains an elastomer having a reactive functional group in an amount of 1 mass% or more based on the total amount of the recycled material (X).
[3] The recycled polyarylene sulfide resin composition (Y) according to [1], [1a] or [2], wherein the recycled material (X) contains an elastomer containing a structural unit derived from an α-olefin and a structural unit derived from a glycidyl ester of an α,β-unsaturated acid.
[4] The recycled material (X) contains an elastomer having a reactive functional group, and the compound (A) contains (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in an amount of 95% by mass or more relative to the total amount of the compound (A). Recycled polyarylene sulfide resin composition (Y) according to any one of [1] to [3].
[5] The recycled polyarylene sulfide resin composition (Y) according to [1], wherein the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass% based on the total amount of the recycled material (X).
[6] A method for producing a recycled polyarylene sulfide resin composition (Y), comprising melt-kneading 100 parts by mass of a recycled material (X) which is a pulverized product of an article containing a polyarylene sulfide resin with a total amount of 0.1 to 3.0 parts by mass of a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound.
[6a] A method for producing a recycled polyarylene sulfide resin composition (Y), comprising melt-kneading 100 parts by mass of a recycled material (X) containing a polyarylene sulfide resin with a total amount of 0.1 to 3.0 parts by mass of a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound.
[7] Prior to melt-kneading, a compound (A) is selected,
Selecting the compound (A),
When the recycled material (X) contains 1% by mass or more of an elastomer having a reactive functional group based on the total amount of the recycled material (X), (A-1) select a compound (A) containing an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in a total amount of 95% by mass or more based on the total amount of the compound (A);
In the case where the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass% relative to the total amount of the recycled material (X), the method for producing a recycled polyarylene sulfide resin composition (Y) described in [6] or [6a] is selected, which comprises a compound (A) containing a total of 95 mass% or more of one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, relative to the total amount of the compound (A).
[8] A polyarylene sulfide resin composition (Z) comprising the recycled polyarylene sulfide resin composition (Y) according to any one of [1] to [5] and a virgin polyarylene sulfide resin or a virgin polyarylene sulfide resin composition (V).
[9] The polyarylene sulfide resin composition (Z) according to [8], wherein the content of the recycled polyarylene sulfide resin composition (Y) is 50 mass% or more based on the total amount of the recycled polyarylene sulfide resin composition (Y) and the virgin polyarylene sulfide resin or virgin polyarylene sulfide resin composition (V).
[10] A method for improving the releasability of a recycled polyarylene sulfide resin or a recycled polyarylene sulfide resin composition, comprising melt-kneading a pellet (P) containing a polyarylene sulfide resin and/or a pulverized product (X) of an article containing a polyarylene sulfide resin with one or more compounds selected from (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, so that the total amount of the compound (A) is 0.1 to 3.0 parts by mass relative to a total of 100 parts by mass of the pellet (P) containing a polyarylene sulfide resin and the pulverized product (X) of the article containing a polyarylene sulfide resin, to obtain pellets (Y) for a recycled polyarylene sulfide resin composition.
[10a] A method for improving the releasability of a polyarylene sulfide resin-containing recycled material (X) during recycling, the method comprising melt-kneading the polyarylene sulfide resin-containing recycled material (X) with one or more compounds (A) selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, such that the total amount of compound (A) is 0.1 to 3.0 parts by mass per 100 parts by mass of the polyarylene sulfide resin-containing recycled material (X).
[11] The method for improving releasability according to [10] or [10a], wherein the pellets (P) containing a polyarylene sulfide resin are obtained by recycling an article containing a polyarylene sulfide resin or a polyarylene sulfide resin composition.
[11a] The method for improving releasability according to [10] or [10a], wherein the recycling material (X) containing a polyarylene sulfide resin is a pulverized product or a repellet of an article containing a polyarylene sulfide resin.
[12] Use of compound (A) for improving the releasability of recycled polyarylene sulfide resin or recycled polyarylene sulfide resin composition, comprising: a pellet (P) containing polyarylene sulfide resin and/or a ground product (X) of an article containing polyarylene sulfide resin; and (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) a fatty acid derivative, and (A-3) a compound (A) containing one or more selected from silicone-based compounds. The total amount of compound (A) is 0.1 to 3.0 parts by mass relative to a total of 100 parts by mass of the pellet (P) containing polyarylene sulfide resin and the ground product (X) of the article containing polyarylene sulfide resin. Use of compound (A) to obtain pellets (Y) for recycled polyarylene sulfide resin composition.
[12a] Use of a compound (A) for improving the releasability during recycling of a polyarylene sulfide resin-containing recycled material (X), comprising melt-kneading the polyarylene sulfide resin-containing recycled material (X) with one or more compounds selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, in such a manner that the total amount of the compound (A) is 0.1 to 3.0 parts by mass per 100 parts by mass of the polyarylene sulfide resin-containing recycled material (X). Use of the compound (A).
[13] The use of the compound (A) according to [12] or [12a], wherein the pellet (P) containing the polyarylene sulfide resin is obtained by recycling an article containing a polyarylene sulfide resin or a polyarylene sulfide resin composition.
[13a] The use of the compound (A) according to [12] or [12a], wherein the recycling material (X) containing a polyarylene sulfide resin is a pulverized product or a repellet of an article containing a polyarylene sulfide resin.

The present invention can provide a recycled polyarylene sulfide resin composition that has excellent releasability from a mold and a method for producing the same. More specifically, it can provide a recycled polyarylene sulfide resin composition that has excellent releasability from a mold while suppressing the generation of mold deposits during molding and a method for producing the same.

FIG. 1 is a diagram illustrating a double cylindrical test piece for measuring mold release resistance during molding, where (a) is a top view, (b) is a bottom view, (c) is a perspective view, and (d) is a dimensional drawing. FIG. 2 is a schematic diagram of a molded body used when evaluating mold deposits, the upper side being a top view and the lower side being a cross-sectional view.

Below, one embodiment of the present disclosure will be described in detail, but the scope of the present disclosure is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. In addition, when multiple upper and lower limit values are described for a specific parameter, any upper and lower limit values can be combined to form a suitable numerical range. The expression "X to Y" indicating a numerical range means "X or more and Y or less." When a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[First embodiment: Recycled polyarylene sulfide resin composition (Y)]
The recycled polyarylene sulfide resin composition (Y) according to the present disclosure comprises 100 parts by mass of a recycled material (X) (hereinafter also referred to as "recycled material (X)") containing a polyarylene sulfide resin, and a total of 0.1 to 3.0 parts by mass of a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound. By containing 100 parts by mass of the recycled material (X) and 0.1 to 3.0 parts by mass of the compound (A), the occurrence of mold deposits during molding of the recycled polyarylene sulfide resin composition (Y) is suppressed, while the releasability from the mold is improved. Recycled polyarylene sulfide resin composition (Y ) can be used alone or as a mixture with virgin material for molding, but with the above configuration, even when the content of the recycled polyarylene sulfide resin composition (Y) is high (the proportion of the recycled polyarylene sulfide resin composition (Y) is 50% or more), the number of times the mold release agent is applied to the mold during molding of the recycled polyarylene sulfide resin composition (Y) can be reduced. As a result, the amount of recycled material used can be increased and work efficiency can be improved. In addition, even when a molded product with a large contact area with the mold is produced, the mold release property from the mold is excellent, so the options for the shape of the parts to which the recycled material can be applied can be expanded. Since the occurrence of mold deposits is suppressed, a molded product with excellent appearance can be obtained.

(Material for recycling (X))
In the first embodiment, the recycled material (X) is a pulverized product of an article containing a polyarylene sulfide resin.
In this specification, "recycling" means to crush an article such as a molded body (a recycled product) and regenerate it as a raw material for manufacturing a molded body, and "material for recycling" means the recycled product. The term "pulverized article containing polyarylene sulfide resin" refers to a material to be used in a recycling process, and "pulverized article containing polyarylene sulfide resin" refers to a pulverized article containing polyarylene sulfide resin (molded article to be recycled).
In contrast, raw materials that have not been used to produce molded bodies (raw materials that have not undergone a molding process) are called "virgin materials," and virgin materials for polyarylene sulfide resins are called "virgin polyarylene sulfide resins." Moreover, a virgin material of a polyarylene sulfide resin composition is referred to as a "virgin polyarylene sulfide resin composition".
The items to be recycled (recyclable items) may be molded products, or may be products that were discharged after being retained in a cylinder for a long time during molding. For example, Examples of such materials include defective products, parts other than the product obtained during injection molding (for example, runners, sprues, etc.), unused products, and lumps of polyethylene sulfide resin material used for purging during molding.
In one embodiment, the recycled material (X) which is a pulverized product of an article containing a polyarylene sulfide resin may be a resin-containing material recycled from an article containing a virgin polyarylene sulfide resin, and the recycled polyarylene sulfide resin may be The resin-containing material may be a recycled article containing the resin. As described above, the "virgin polyarylene sulfide resin" means a polyarylene sulfide resin that has never been subjected to a molding process. Sulfide resin does not have a thermal history during molding, whereas recycled polyarylene sulfide resin has a thermal history of being heated at high temperatures during the manufacturing process of recycled molded products.

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

The arylene group is not particularly limited, but examples thereof include p-phenylene group, m-phenylene group, o-phenylene group, substituted phenylene group, p,p'-diphenylenesulfone group, p,p'-biphenylene group, p,p'-diphenylene ether group, p,p'-diphenylenecarbonyl group, and naphthalene group.

Polyarylene sulfide resins can be homopolymers using the same repeating units among the repeating units shown in the above general formula (I), as well as copolymers containing different types of repeating units. As homopolymers, those having p-phenylene sulfide groups as repeating units, which have p-phenylene groups as arylene groups, are preferred. This is because homopolymers having p-phenylene sulfide groups as repeating units 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 extremely excellent physical properties can be obtained.

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 mol% or more of p-phenylene sulfide groups is more preferred, and a polymer containing 80 mol% or more is even more preferred. The polyarylene sulfide resin having phenylene sulfide groups is a polyphenylene sulfide resin (PPS resin).

Polyarylene sulfide resins are generally known to have a substantially linear molecular structure with no branching or crosslinking, and a structure with branching or crosslinking, depending on the manufacturing method. In one embodiment, from the viewpoint of improving the toughness of the molded product, it is more preferable that the resin does not contain a structure with a crosslinking structure.

The melt viscosity of the recycling material (X) is not limited as long as it does not impair the effects of the present disclosure, and the melt viscosity measured at 310° C. and a shear rate of 1200 sec ⁻¹ may be 5 to 300 Pa·s, or 8 to 250 Pa·s.

The recycled material (X) may contain other components contained in the recycled molded product. In one embodiment, the content of polyarylene sulfide resin in the recycled material (X) is preferably 30 to 99 mass% and more preferably 50 to 95 mass% based on the total amount of the recycled material (X). In one embodiment, the content of polyarylene sulfide resin in the thermoplastic resin (excluding elastomer) contained in the recycled material (X) is preferably 80 to 100 mass% and more preferably 90 to 100 mass% based on the total amount of the thermoplastic resin (excluding elastomer).

Other components that the recycled material (X) may contain include, for example, elastomers, organic or inorganic fillers, and other additives that are generally added to thermoplastic resins (for example, flame retardants, colorants such as dyes and pigments, stabilizers such as antioxidants and UV absorbers, lubricants, crystallization accelerators, crystal nucleating agents, etc.).

Examples of the elastomer include olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, etc., which may be grafted. It is preferable to include one or more selected from these, and it is more preferable to include an olefin-based elastomer.

The elastomer 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 (such as glycidyl (meth)acrylate); or an epoxy-modified elastomer obtained by epoxidizing the unsaturated bond of an elastomer.

Olefin-based elastomers include 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 ester, methacrylic acid glycidyl ester, and ethacrylic acid glycidyl ester. Preferred specific examples of olefin-based elastomers 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.

Examples of styrene-based elastomers include block copolymers consisting of a polymer block mainly made of a vinyl aromatic compound such as styrene and a polymer block mainly made of a non-hydrogenated and/or hydrogenated conjugated diene compound. Specific examples of preferred styrene-based elastomers include styrene-butadiene rubber (SBR) and styrene-ethylene-butylene-styrene block copolymer (SEBS). The styrene-based elastomer may also 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 elastomer may be contained alone or in combination of two or more types.

Examples of polyester-based elastomers include block copolymers in which aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate serve as hard segments, and polyethers such as polyethylene glycol and polytetramethylene glycol, or aliphatic polyesters such as polyethylene adipate, polybutylene adipate, and polycaprolactone serve as soft segments. The polyester-based elastomers may be used alone or in combination of two or more types.

Elastomers are sometimes mixed with virgin materials to improve impact resistance, etc., but in recycled materials, at least a part of the chemical structure may change due to shearing when crushing the recycled product or thermal history due to having been through one or more molding processes, which may cause deterioration of releasability from a mold. In particular, when the elastomer has a reactive functional group, the releasability from a mold may be further deteriorated when molding the recycled polyarylene sulfide resin composition. However, according to the recycled polyarylene sulfide resin composition (Y) of the present disclosure, even if the recycled material (X) contains an elastomer (especially an elastomer having a reactive functional group), it is possible to improve the releasability from a mold during molding. In one embodiment, the recycled material (X) may contain an elastomer having a reactive functional group. In another embodiment, the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer may be less than 5 mass%, less than 1 mass%, or less than 0.01 mass% relative to the total amount of the recycled material (X).

The term "reactive functional group" used here refers to a functional group that has a high affinity (reactivity) with metal materials at the melting temperature of the resin. Examples of reactive functional groups include glycidyl groups, epoxy groups, carboxyl groups, hydroxyl groups, acid anhydride groups, salts of carboxyl groups, carboxylate groups, amide groups, amino groups, isocyanate groups, isothiocyanate groups, acetoxy groups, silanol groups, alkoxysilane groups, alkynyl groups, oxazoline groups, thiol groups, and sulfonic acid groups. In one embodiment, the elastomer may include an olefin-based elastomer, a styrene-based elastomer, or a polyester-based elastomer that includes one or more groups selected from a glycidyl group, an epoxy group, a carboxyl group, a hydroxyl group, an acid anhydride group, a salt of a carboxyl group, a carboxylate ester group, an amide group, and 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 recycled material (X) may contain, as an elastomer having a reactive functional group, one or more selected from an olefin-based elastomer containing a structural unit derived from an α-olefin and a structural unit derived from a glycidyl ester of an α,β-unsaturated acid, and a styrene-based elastomer containing an epoxidized styrene-diene copolymer in which the unsaturated bond of the diene has been epoxidized.

In one embodiment, the recycled material (X) may include an elastomer that includes a structural unit derived from an α-olefin and a structural unit derived from a glycidyl ester of an α,β-unsaturated acid. In one embodiment, the recycled material (X) may include an elastomer that includes a glycidyl ester of methacrylic acid.

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% of the total amount of the elastomer, or may be 0.5 to 8 mass%. 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.

In one embodiment, the content of the elastomer is preferably 1% by mass or more, more preferably 1 to 20% by mass, and even more preferably 2 to 15% by mass, based on the total amount of the recycled material (X).
In one embodiment, the recycled material (X) may contain an elastomer having a reactive functional group in an amount of 1% by weight or more, 2% by weight or more, or 3 to 10% by weight, based on the total amount of the recycled material (X).

In another embodiment, the elastomer content can be less than 1% by mass, less than 0.8% by mass, or 0% by mass, based on the total amount of recycled material (X).

Organic or inorganic fillers include fibrous fillers such as high-melting point organic fibrous substances such as glass fiber, carbon fiber, zinc oxide fiber, titanium oxide fiber, wollastonite, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel fiber, aluminum fiber, titanium fiber, copper fiber, brass fiber, polyamide, high molecular weight polyethylene, aramid, fluororesin, polyester resin, and acrylic resin; carbon black, graphite, silica, quartz powder, and glass beads. , 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 alumina (granular), metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and other powdered and granular fillers such as silicon carbide, silicon nitride, boron nitride, and various metal powders; plate-shaped fillers such as mica, glass flakes, talc (plate-shaped), mica, kaolin, clay, alumina (plate-shaped), and various metal foils; and the like. In terms of mechanical strength, heat resistance, and the like, it is preferable to contain an inorganic filler.

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

The method for producing recycled material (X), which is a pulverized product of an article containing polyarylene sulfide resin, is not limited, and can be obtained, for example, by pulverizing a molded product of polyarylene sulfide resin (preferably a molded product of virgin polyarylene sulfide resin) using a known pulverizer.

The recycled molded products that are the raw material for the recycled material (X) include, for example, defective products that arise during the manufacturing process of molded products, parts other than the product obtained during injection molding (e.g., runners, sprues, etc.), unused products, and chunks of polyethylene sulfide resin material used for purging during molding, and it is preferable that the recycled molded products include one or more selected from these. In one embodiment, the recycled molded products may be injection molded products.

The average particle size of the particles after crushing the recycled molded products is not limited, but for example, the volume-based cumulative 50% diameter (D50) measured by the laser diffraction scattering method is preferably 0.3 to 20 mm, more preferably 0.4 to 15 mm, even more preferably 1 to 10 mm, and even more preferably 1 to 3 mm.

(Compound (A))
Examples of the compound (A) include (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C (hereinafter also referred to as "(A-1) olefin resin"), (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, and it is preferable to contain one or more selected from these. By containing the compound (A), the releasability of the recycled polyarylene sulfide resin composition (Y) from a mold during molding is improved.

In one embodiment, the content of one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound is preferably 95% by mass or more in total relative to the total amount of compound (A), more preferably 98% by mass or more in total, and it is even more preferable that compound (A) consists of one or more selected from these.

(A-1) Olefin resins having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C include, for example, polyolefin resins having a degree of polymerization of about 500 to 1000 and 1 to 10 (preferably 1 to 4) carbon atoms, specifically, for example, polyethylene resins, polypropylene resins, ethylene-olefin copolymers, etc., each having a degree of polymerization of 500 to 1000. These (A-1) olefin resins may be used alone or in combination of two or more. Of these, it is preferable that the resin contains polyethylene resin and/or polypropylene resin, and it is more preferable that the resin contains polyethylene resin.

The melt viscosity of the (A-1) olefin resin at 140°C is 0.1 to 8.0 Pa·s, preferably 0.5 to 7.0 Pa·s, more preferably 1.0 to 6.5 Pa·s, and particularly preferably 2.0 to 6.0 Pa·s. The (A-1) olefin resin with a melt viscosity of 0.1 to 8.0 Pa·s at 140°C has good dispersibility in the recycled material (X) and is easily dispersed uniformly. As a result, it is easy to obtain a good effect of improving releasability. In addition, since the (A-1) olefin resin is not easily decomposed during molding, it is easy to reduce the volatile components derived from the (A-1) olefin resin, and mold deposits (MD) can be reduced. The melt viscosity at 140°C can be measured using a B-type viscometer (for example, "RB-80H" manufactured by Toki Sangyo Co., Ltd.) based on JIS K7117.

(A-2) Fatty acid derivatives are compounds obtained by chemical reactions of saturated and/or unsaturated fatty acids having at least one carboxyl group, or saturated and/or unsaturated fatty acids with other compounds. (A-2) fatty acid derivatives include fatty acid salts, fatty acid esters, fatty acid amides, etc., and it is preferable to include at least one selected from these.

Examples of fatty acid salts include fatty acid metal salts, such as lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of fatty acids (preferably saturated or unsaturated C8-35 fatty acids, more preferably saturated or unsaturated C10-20 fatty acids).
Examples of saturated or unsaturated C8-35 fatty acids include saturated fatty acids such as lauric acid (dodecanoic acid), isodecanoic acid, tridecanoic acid, myristic acid (tetradecanoic acid), pentadecylic acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), isostearic acid, tuberculostearic acid (nonadecanoic acid), 2-hydroxystearic acid, arachidic acid (icosanoic acid), behenic acid (docosanoic acid), lignoceric acid (tetradocosanoic acid), cerotic acid (hexadocosanoic acid), montanic acid (octadocosanoic acid), and melissic acid. unsaturated fatty acids such as myristoleic acid (tetradecenoic acid), palmitoleic acid (hexadecenoic acid), oleic acid (cis-9-octadecenoic acid), elaidic acid (trans-9-octadecenoic acid), ricinoleic acid (octadecadienoic acid), vaccenic acid (cis-11-octadecenoic acid), linoleic acid (octadecadienoic acid), linolenic acid (9,11,13-octadecatrienoic acid), elestearic acid (9,11,13-octadecatrienoic acid), gadoleic acid (icosanoic acid), erucic acid (docosanoic acid), and nervonic acid (tetradocosanoic acid).
These fatty acid metal salts may be used alone or in combination of two or more. Among them, from the viewpoint of cost and availability, zinc salts, calcium salts, or aluminum salts of fatty acids having less than 22 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, are preferred, and calcium stearate and magnesium stearate are more preferred.

Examples of fatty acid esters include esters of aliphatic alcohols and fatty acids, and preferred are esters of polyhydric alcohols and fatty acids. Examples of polyhydric alcohols include glycol, polyglycol, glycerin, polyglycerin, propylene glycol, pentaerythritol, sorbitol, mannitol, etc. Examples of fatty acids include saturated or unsaturated C8-35 fatty acids (preferably C10-20 fatty acids), and examples of such fatty acids include those described above for the fatty acid metal salts.
These fatty acid esters may be used alone or in combination of two or more. Among them, from the viewpoint of cost and availability, esters of one or more selected from glycol, propylene glycol, and pentaerythritol and one or more fatty acids selected from fatty acids having less than 22 carbon atoms such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid are preferred, and pentaerythritol stearates such as pentaerythritol tristearate and pentaerythritol tetrastearate are more preferred.

Examples of fatty acid amides include C8-35 fatty acid amides, alkylene fatty acid amides, etc. Examples of C8-35 fatty acid amides include oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, ethylene bislauric acid amide, etc. Examples of alkylene fatty acid amides include methylene bisstearic acid amide, ethylene bisstearic acid amide, etc.
These fatty acid amides may be used alone or in combination of two or more. Among these, ethylene bisstearic acid amide is more preferred from the viewpoints of cost and availability.

Examples of the silicone-based compound (A-3) include silicone oil and silicone resin. The silicone-based compound (A-3) may be used alone or in combination of two or more types. Among these, silicone oil is more preferred from the standpoint of price and availability.

The inventors' research has revealed that when the recycled material (X) contains an elastomer having a reactive functional group, the releasability can be further improved by selecting and using, from among the above compounds (A), (A-1) a compound (A) that has a high content of (or is made of) an olefin resin with a melt viscosity of 0.1 to 8.0 Pa·s at 140°C.

In one embodiment, when the recycled material (X) contains an elastomer having a reactive functional group (preferably the content of the elastomer having a reactive functional group is preferably 1% by mass or more, more preferably 3 to 10% by mass, based on the total amount of the recycled material (X)), from the viewpoint of further improving releasability, the compound (A) preferably contains (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, more preferably contains (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in an amount of 95% by mass or more, or 98% by mass or more, based on the total amount of the compound (A), and further preferably consists of (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C.

In one embodiment, when the recycled material (X) contains an elastomer having a reactive functional group (preferably the content of the elastomer having a reactive functional group is preferably 1% by mass or more, more preferably 3 to 10% by mass, based on the total amount of the recycled material (X)), it is preferable that the compound (A) contains (A-1) olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in an amount of 95% by mass or more based on the total amount of the compound (A), and does not contain (A-2) fatty acid derivatives and (A-3) silicone-based compounds, or the content of (A-2) fatty acid derivatives and (A-3) silicone-based compounds is less than 5% by mass in total based on the total amount of the compound (A).

In one embodiment, the recycled material (X) can be configured to include an elastomer containing structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid, and to include compound (A) that contains 95% by mass or more (A-1) of an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C relative to the total amount of compound (A) (preferably 98% by mass or more, and more preferably consists of (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C).

In another embodiment, when the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass %, preferably less than 0.8 mass %, of the total amount of the recycled material (X), the compound (A) may contain one or more selected from the above-mentioned (A-1) olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) fatty acid derivative, and (A-3) silicone-based compound, and from the viewpoint of easier improvement of releasability, it is preferable that the compound (A) contains one or more selected from (A-1) olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C and (A-2) fatty acid ester.

In one embodiment, the compound (A) may be an organic substance that is solid or liquid at room temperature (20 to 25°C). The organic substance that is solid or liquid at room temperature (20 to 25°C) may be melt-kneaded with the recycling material (X) during repelletization. The resulting repellet contains the compound (A) in the matrix of the recycling material (X). In this specification, room temperature (20 to 25°C) preferably means 25°C.
In another embodiment, compound (A) may be an organic substance that is solid at room temperature (20 to 25° C.) and has a melting point of 50 to 135° C. (preferably 55 to 130° C., more preferably 70 to 125° C., 90 to 120° C.). The melting point is a value measured according to a DSC method (method described in JIS K7121).

(Content)
The content of the compound (A) is 0.1 to 3.0 parts by mass relative to 100 parts by mass of the recycled material (X), preferably 0.15 to 2.5 parts by mass, more preferably 0.2 to 2.0 parts by mass, even more preferably 0.3 to 1.5 parts by mass, and particularly preferably 0.4 to 1.2 parts by mass. By making the content 0.1 parts by mass or more relative to 100 parts by mass of the recycled material (X), the releasability from the mold when molding the recycled material (X) can be improved. By making the content 3.0 parts by mass or less, the occurrence of mold deposits (MD) can be suppressed. The total coating amount of the compound (A) may be 0.4 parts by mass, 0.8 parts by mass, or 1.2 parts by mass in the range of 0.1 to 3.0 parts by mass relative to 100 parts by mass of the recycled material (X), and may be in the range of these upper and/or lower limits.

(Other additives)
The recycled polyarylene sulfide resin composition (Y) may contain additives as necessary. Examples of the additives include the same components as those that may be contained in the recycled material (X) described above.

(Release resistance)
In one embodiment, the recycled polyarylene sulfide resin composition (Y) preferably has a molded article having a release resistance of 410 N or less, more preferably 405 N or less, and even more preferably 400 N or less.
The demolding resistance value is a double cylinder demolding resistance value, and means the resistance when the double cylinder molded product shown in FIG. 1 is demolded from a mold.
Fig. 1(a) is a top view of the double cylindrical molded product, Fig. 1(b) is a bottom view of the double cylindrical molded product, Fig. 1(c) is a perspective view of the double cylindrical molded product, and Fig. 1(d) is a dimensional drawing of the double cylindrical molded product, the dimensions in Fig. 1(a) and (d) being in mm. The gate size of the double cylindrical molded product is 5 mm x 2.5 mm.

The double cylindrical molded product shown in Figure 1 has a double cylindrical shape with a first cylinder 1 on the inside and a second cylinder 2 on the outside, and the first cylinder 1 and second cylinder 2 are connected at four points by a 4 mm shaft. The first cylinder 1 has a height of 20 mm, an outer diameter of 18 mm, and an inner diameter of 9 mm, while the second cylinder 2 has a height of 40 mm, an outer diameter of 40 mm, and an inner diameter of 30 mm. The thickness of the side of the first cylinder 1 is 4.5 mm, and the thickness of the bottom and side of the second cylinder 2 is 5 mm. The second cylinder 2 is a bottomed cylinder, but has an opening at the part of the first cylinder 1.

(Mold adhesion)
In one embodiment, the recycled polyarylene sulfide resin composition (Y) preferably has a mold adhesion amount measured under the following conditions of 100 μg or less, more preferably 90 μg or less, and even more preferably 80 μg or less.
Using the injection molding machine and conditions below, a molded article having the dimensions and shape shown in Figure 2 is molded continuously for 4 hours (1000 times). The total weight of the vent and cavity parts removed from the mold is measured before and after the continuous molding. The change in the total weight of the vent and cavity parts before and after the continuous molding is calculated as the weight (μg) of the matter adhering to the mold.
Injection molding machine: FANUC ROBOSHOT S2000i30A
Cylinder temperature: 340°C
Injection time: 2 seconds Cooling time: 10 seconds Mold temperature: 140°C

(Application)
The recycled polyarylene sulfide resin composition (Y) can be suitably used as a resin composition for injection molding or a resin composition for extrusion molding.

[Second embodiment: Method for producing recycled polyarylene sulfide resin composition (Y)]
The method for producing the recycled polyarylene sulfide resin composition (Y) according to this embodiment includes melt-kneading 100 parts by mass of a recycled material (X) containing a polyarylene sulfide resin and 0.1 to 3.0 parts by mass of a compound (A) together with additives used as necessary. In the second embodiment, the recycled material (X) is a pulverized product containing a polyarylene sulfide resin. The compound (A) and additives, as well as the amount of each component, are the same as those in the first embodiment, and therefore will not be described here.

(Melting and kneading process)
The melt-kneading temperature is a temperature equal to or higher than the melting point of the recycling material (X), and is usually 280 to 360°C, preferably 290 to 350°C.

The mixing method is not particularly limited as long as it can uniformly mix the recycled material (X) and the compound (A), and examples of the method include a melt-kneading method using a melt-kneading device such as a conventional single-screw or twin-screw extruder. After melt-kneading and extruding each component, the resulting recycled polyarylene sulfide resin composition (Y) can be processed into the desired form such as powder, flakes, pellets, etc.

(Compound (A) Selection Step)
In one embodiment, the method for producing the recycled polyarylene sulfide resin composition (Y) preferably includes a step of selecting a compound (A) prior to melt kneading in order to further improve the releasability of the recycled polyarylene sulfide resin composition (Y). As described above, when the recycled material (X) contains an elastomer having a reactive functional group, the compound (A) is selected and used as (A-1) a compound (A) having a high content (or consisting of) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, thereby further improving the releasability.

In one embodiment, the step of selecting compound (A) comprises:
When the recycled material (X) contains an elastomer having a reactive functional group in an amount of 1% by mass or more (preferably 2% by mass or more, more preferably 3 to 10% by mass) based on the total amount of the recycled material (X), (A-1) a compound (A) containing an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C is selected, preferably (A-1) a compound (A) containing an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C is selected,
When the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass%, preferably less than 0.8 mass%, of the total amount of the recycled material (X), a compound (A) is selected that contains a total of 95 mass% or more of one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, based on the total amount of the compound (A) (preferably consisting of one or more selected from these), preferably a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s and (A-2) a fatty acid ester, more preferably a compound (A) containing one or more selected from a C1-4 olefin resin such as a polyethylene resin, an ethylene copolymer, or a polypropylene resin; and a C8-35 fatty acid ester such as pentaerythritol tristearate or pentaerythritol tetrastearate.

[Third embodiment: Method for producing molded article containing recycled polyarylene sulfide resin composition (Y)]
The recycled polyarylene sulfide resin composition (Y) can be molded and processed by known methods such as injection molding, contouring and solidification extrusion, press molding, and spinning. The recycled polyarylene sulfide resin composition (Y) has excellent releasability from a mold, so that the number of times a mold release agent is applied to the mold during molding can be reduced. In addition, even when a molded product having a large contact area with the mold is produced, the mold release property is excellent, so that the choice of part shape can be expanded.

In one embodiment, a method for producing a molded product containing recycled polyarylene sulfide resin composition (Y) includes continuously injecting or extruding the above-mentioned recycled polyarylene sulfide resin composition (Y) into a mold together with other thermoplastic resins and additives as necessary, and applying a release agent to the mold, and the number of times that the release agent is applied to the mold may be once for every 10 or more injections or extrusions. The release agent applied to the mold is not limited, and can be selected from known release agents.

The recycled polyarylene sulfide resin composition (Y) has excellent releasability from a mold, so even when molding products with a large contact area with the mold in injection or extrusion molding, the number of times a mold release agent needs to be applied to the mold can be reduced.

[Fourth embodiment: Polyarylene sulfide resin composition (Z)]
The above-mentioned recycled polyarylene sulfide resin composition (Y) can be mixed with other thermoplastic resins as necessary 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.

In one embodiment, the polyarylene sulfide resin composition (Z) preferably contains the recycled polyarylene sulfide resin composition (Y) and the virgin polyarylene sulfide resin or virgin polyarylene sulfide resin composition (V). By containing the recycled polyarylene sulfide resin composition (Y), the recycled material can be effectively utilized and the resin composition can be made excellent in releasability from a mold. In addition, the occurrence of mold deposits during molding can be suppressed. By containing the virgin polyarylene sulfide resin or virgin polyarylene sulfide resin composition (V), the excellent physical properties of the polyarylene sulfide resin can be reinforced. As described above, the "virgin polyarylene sulfide resin composition" means a virgin material of the polyarylene sulfide resin composition.
The content of the recycled polyarylene sulfide resin composition (Y) is preferably 50% by mass or more, more preferably 50 to 99.99% by mass, and even more preferably 60 to 100% by mass in the total amount of the recycled polyarylene sulfide resin composition (Y) and the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) in terms of increasing the amount of recycled material used. The polyarylene sulfide resin composition (Z) has excellent releasability from a mold even when the content of the recycled polyarylene sulfide resin composition (Y) is high.

The polyarylene sulfide resin contained in the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) can be exemplified by the same ones as those described for the recycled material (X) in the first embodiment, and from the viewpoint of quality control, etc., it is preferable that the composition is the same as that of the polyarylene sulfide resin in the recycled material (X). The virgin polyarylene sulfide resin composition can contain other components such as the compound (A), elastomer, organic or inorganic filler, release agent, other additives generally added to thermoplastic resins (e.g., flame retardants, colorants such as dyes and pigments, stabilizers such as antioxidants and ultraviolet absorbers, lubricants, crystallization promoters, crystal nucleating agents, etc.) as the recycled material (X). Details of the other components are as described in the first embodiment. In one embodiment, from the viewpoint of quality control, etc., it is preferable that the virgin polyarylene sulfide resin composition has the same composition as the recycled polyarylene sulfide resin composition (Y) (e.g., the type and content of additives are the same). In one embodiment, when the recycled polyarylene sulfide resin composition (Y) does not contain an elastomer having a reactive functional group, it is preferable that the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) also does not contain an elastomer having a reactive functional group. In this case, the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) may or may not contain the compound (A). When the compound (A) is contained, the type is not limited. In another embodiment, when the recycled polyarylene sulfide resin composition (Y) contains an elastomer having a reactive functional group, it is preferable that the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) also contains an elastomer having a reactive functional group, and it is more preferable that the type and content of the elastomer are the same. In this case, the virgin polyarylene sulfide resin or the virgin polyarylene sulfide resin composition (V) preferably contains a compound (A), and it is more preferable to select (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s.

The melt viscosity of the virgin polyarylene sulfide resin is not particularly limited as long as it is within a range that does not impair the effects of the present disclosure. From the viewpoint of the balance between mechanical properties and fluidity, the melt viscosity measured at 310° C. and a shear rate of 1200 sec ⁻¹ is preferably 300 Pa·s or less, and more preferably 250 Pa·s or less.

The method for producing the polyarylene sulfide resin composition (Z) is not limited, and the recycled polyarylene sulfide resin composition (Y) may be dry blended with another thermoplastic resin (preferably virgin polyarylene sulfide resin), or may be melt-kneaded using a conventional melt-kneading device such as a single-screw or twin-screw extruder, or may be mixed in the hopper (material supply member) of an injection molding machine.

The method for producing a molded article containing the polyarylene sulfide resin composition (Z) can be carried out in the same manner as the method for producing a molded article containing the recycled polyarylene sulfide resin composition (Y) described in the third embodiment.

(Application)
The polyarylene sulfide resin composition (Z) can be suitably used as a resin composition for injection molding or a resin composition for extrusion molding.

[Fifth embodiment: Method for improving releasability]
The method for improving the releasability of recycled polyarylene sulfide resin or recycled polyarylene sulfide resin composition according to the present disclosure includes melt-kneading pellets (P) containing a polyarylene sulfide resin and/or pulverized product (X) of an article containing a polyarylene sulfide resin with a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, so that the total amount of compound (A) is 0.1 to 3.0 parts by mass relative to a total of 100 parts by mass of the pellets (P) containing a polyarylene sulfide resin and the pulverized product (X) of the article containing a polyarylene sulfide resin, to obtain pellets (Y) for a recycled polyarylene sulfide resin composition.

"For use in recycled polyarylene sulfide resin compositions" means that the product is intended to be used as a polyarylene sulfide resin composition produced by crushing articles such as molded bodies (recycled products) and recycling them as a raw material for use in producing molded bodies, or as a raw material for such polyarylene sulfide resin compositions.

The method for improving the releasability according to the fifth embodiment can also be expressed as follows. That is, the method for improving the releasability is a method for improving the releasability during recycling of a regenerated material (X) containing a polyarylene sulfide resin, and includes melt-kneading a regenerated material (X) containing a polyarylene sulfide resin and (A-1) a compound (A) containing one or more selected from an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140 ° C., (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, so that the total amount of the compound (A) is 0.1 to 3.0 parts by mass relative to 100 parts by mass of the regenerated material (X) containing a polyarylene sulfide resin.
According to the method of the present embodiment, the releasability of the recycled material (X) when recycling can be improved. In addition, the occurrence of mold deposits at that time can be suppressed. In the fifth embodiment, the recycled material (X) may be a pellet (P) (e.g., a virgin pellet or a repellet) containing a polyarylene sulfide resin, or may be a pulverized product of an article containing a polyarylene sulfide resin or a composition thereof. In one embodiment, the recycled material (X) is preferably a pulverized product or a repellet of an article containing a polyarylene sulfide resin or a composition thereof.

In this specification, "improving releasability" means that the releasability from a mold during molding of the recycled polyarylene sulfide resin composition is improved compared to when compound (A) is not blended. In one embodiment, the method for improving releasability is preferably a method that can improve releasability while suppressing the occurrence of mold deposits. "Improving releasability during recycling" means, when the recycled material (X) is a virgin pellet containing polyarylene sulfide resin, that the virgin pellet is molded once to obtain a molded product, and then the molded product is crushed to obtain a crushed product or further formed into a repellet, and the mold release property is improved when the crushed product or the repellet is molded. When the recycled material (X) is a crushed product or a repellet of an article containing polyarylene sulfide resin, it means that the mold release property is improved when the crushed product or the repellet is molded.

When the recycled material (X) is a pulverized product of an article containing polyarylene sulfide resin, "pulverized product of an article containing polyarylene sulfide resin" means, as described above, a pulverized product of an article containing polyarylene sulfide resin (molded product to be recycled). The recycled product (recycled product) may be a molded product, or may be one that has been 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, parts other than the product obtained during injection molding (e.g., runners, sprues, etc.), unused products, and lumps of polyarylene sulfide resin material used for purging during molding.

When the recycled material (X) is a pellet (P) containing a polyarylene sulfide resin, the pellet (P) may be a virgin pellet or a repellet. That is, the polyarylene sulfide resin contained in the pellet (P) containing a polyarylene sulfide resin may be a virgin polyarylene sulfide resin or a recycled polyarylene sulfide resin. When the polyarylene sulfide resin contained in the pellet (P) containing a polyarylene sulfide resin is a virgin polyarylene sulfide resin, a predetermined amount of the above-mentioned compound (A) is mixed with the pellet (P) containing a virgin polyarylene sulfide resin, melt-kneaded, and pelletized again to obtain a compound (A)-containing virgin pellet (P1). In this case, the amount of compound (A) is 0.04 to 3.0 parts by mass per 100 parts by mass of the pellet (P) containing a virgin polyarylene sulfide resin. The virgin pellets (P1) containing compound (A) can be used as a raw material for a recycled polyarylene sulfide resin composition. That is, the virgin pellets (P1) are once molded into a molded body by a known method such as injection molding or extrusion molding (or discharged after a long residence in a cylinder during molding), and then crushed and repelletized to form a recycled polyarylene sulfide resin composition. The virgin pellets (P1) have excellent releasability from a mold when initially molded, and also have excellent releasability from a mold when subsequently recycled as pellets (Y) for a recycled polyarylene sulfide resin composition.

When the polyarylene sulfide resin contained in the pellets (P) containing polyarylene sulfide resin is a recycled polyarylene sulfide resin, a predetermined amount of the above-mentioned compound (A) is mixed with the pellets (P) containing recycled polyarylene sulfide resin, melt-kneaded, and pelletized again to obtain recycled pellets (P2) containing compound (A). The recycled pellets (P2) containing compound (A) can be used as a recycled polyarylene sulfide resin composition. In this case, the amount of compound (A) mixed is 0.04 to 3.0 parts by mass per 100 parts by mass of the pellets (P) containing recycled polyarylene sulfide resin. The pellets (P) containing recycled polyarylene sulfide resin are obtained by crushing an article containing polyarylene sulfide resin into pellets.

The shape of the pellets (P) containing polyarylene sulfide resin is not particularly limited, and can be any shape, such as cylindrical (approximately cylindrical), spherical, etc.

In one embodiment, the pellets (P) containing polyarylene sulfide resin are preferably made by recycling an article containing polyarylene sulfide resin or a polyarylene sulfide resin composition (recycled material). In other words, the recycled material (X) containing polyarylene sulfide resin is preferably a pulverized product or repellet of an article containing polyarylene sulfide resin.

The details of the types and amounts of the "polyarylene sulfide resin" and "compound (A)" and the mixing method are the same as those described in the section on the recycled polyarylene sulfide resin composition (Y) and its manufacturing method in the first embodiment.

[Sixth embodiment: Use of compound (A)]
The use of compound (A) according to the present disclosure is the use of compound (A) for improving the releasability of recycled polyarylene sulfide resin or recycled polyarylene sulfide resin composition, and includes melt-kneading a pellet (P) containing polyarylene sulfide resin and/or a ground product (X) of an article containing polyarylene sulfide resin with one or more selected from (A-1) an olefin resin having a melt viscosity at 140 ° C. of 0.1 to 8.0 Pa · s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, so that the total amount of compound (A) is 0.1 to 3.0 parts by mass relative to a total of 100 parts by mass of the pellet (P) containing polyarylene sulfide resin and the ground product (X) of the article containing polyarylene sulfide resin, to obtain pellets (Y) for the recycled polyarylene sulfide resin composition.

The use of the compound (A) according to the sixth embodiment can also be expressed as follows. That is, the use of the compound (A) is the use of the compound (A) for improving the releasability during recycling of the polyarylene sulfide resin-containing regenerated material (X), and includes melt-kneading the polyarylene sulfide resin with the regenerated material (X) and (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140 ° C., (A-2) a fatty acid derivative, and (A-3) a compound (A) containing one or more selected from a silicone-based compound, so that the total amount of the compound (A) is 0.1 to 3.0 parts by mass relative to 100 parts by mass of the regenerated material (X).
By using the compound (A) of this embodiment, it is possible to improve the releasability when recycling the regenerated material (X), and also to suppress the occurrence of mold deposits during recycling.

In the sixth embodiment, the recycled material (X) may be a pellet (P) (e.g., a virgin pellet or a repellet) containing a polyarylene sulfide resin, or may be a ground product of an article containing a polyarylene sulfide resin or a composition thereof. In one embodiment, the recycled material (X) is preferably a ground product or a repellet of an article containing a polyarylene sulfide resin or a composition thereof.
Regarding "improving releasability during recycling" and "pellets (P) containing polyarylene sulfide resin", they are as described in the section on the method for improving releasability in the fifth embodiment.
When the recycled material (X) is a pulverized product of an article containing a polyarylene sulfide resin, the "pulverized product of an article containing a polyarylene sulfide resin" is as described in the fifth embodiment.
When the recycled material (X) is a pellet (P) containing a polyarylene sulfide resin, the pellet (P) may be a virgin pellet or a recycled pellet. The "pellet (P)" is as described in the fifth embodiment.
In one embodiment, the pellets (P) containing the polyarylene sulfide resin are preferably made by recycling an article containing a polyarylene sulfide resin or a polyarylene sulfide resin composition (recycled material). That is, the recycled material (X) is preferably a pulverized product or repellet of an article containing a polyarylene sulfide resin.
Details of the types and amounts of the "polyarylene sulfide resin" and "compound (A)", as well as the compounding method, etc., are the same as those described in the section on the recycled polyarylene sulfide resin composition (Y) and its manufacturing method in the first embodiment.

The present invention will be explained in more detail below with reference to examples, but the interpretation of the present invention is not limited to these examples.

[material]
(Recycling material (X1): crushed injection molding products)
An injection-molded product of a resin composition (virgin PPS resin composition (V1) used in Reference Example 1 described later) containing 65 mass % polyphenylene sulfide resin (manufactured by Kureha Corporation, Fortron (registered trademark) KPS), 30 mass % glass fiber, and 4 mass % elastomer (composition: E-GMA-MA (glycidyl methacrylate content: 3 mass %)), with the remainder being additives, was pulverized by a mechanical pulverizer to obtain a pulverized material (recycling material) (X1) of the injection-molded product.

(Recycling material (X2): crushed injection molding products)
An injection-molded product of a resin composition (containing 69 mass % of polyphenylene sulfide resin (manufactured by Kureha Corporation, Fortron (registered trademark) KPS), 30 mass % of glass fiber, and the remainder being additives (containing no elastomer component; virgin PPS resin composition (V2) used in Reference Example 2 described later)) was pulverized by a mechanical pulverizer to obtain a pulverized material (recycled material) (X2) of the injection-molded product.

(Recycling material (X3): crushed injection molding products)
An injection-molded product of a resin composition containing 0.4 parts by mass of compound (A1) per 100 parts by mass of virgin PPS resin composition (V1) used in Reference Example 1 described later was pulverized by a mechanical pulverizer to obtain a pulverized material (recycled material) (X3) of the injection-molded product.

Compound (A1): Polyethylene resin (manufactured by Sanyo Chemical Industries, Ltd., "Sanwax 161-P", melting point 103°C, melt viscosity at 140°C 4.3 Pa·s)
Compound (A2): Pentaerythritol stearate (manufactured by NOF Corporation, "Unistar H476", melting point 63°C)
The melting points of compound (A1) and compound (A2) and the melt viscosity of compound (A1) at 140° C. were measured by the following methods.
(Melting Point)
The melting point (Tm) was measured by the DSC method (method described in JIS K7121) using a DSC device (differential scanning calorimeter, DSC-Q1000, manufactured by TA Instruments) under conditions of a nitrogen atmosphere and a temperature rise rate of 10° C./min.
(Viscosity at 140° C.)
The viscosity was measured at 140° C. using a Brookfield viscometer ("RB-80H" manufactured by Toki Sangyo Co., Ltd.) in accordance with JIS K7117 (1999).

[Examples 1 to 6]
The crushed material of the injection molded product and the compound (A1) or compound (A2) shown in Table 1 were dry-blended in the content ratio shown in Table 1. This was put into a twin-screw extruder with a cylinder temperature of 320°C and melt-kneaded to obtain pellets (repellet) of the recycled polyarylene sulfide resin composition (Y) of Examples 1 to 6.

[Example 7]
The recycled material (X3) was fed into a twin-screw extruder with a cylinder temperature of 320°C and melt-kneaded to obtain pellets (repellet) of the recycled polyarylene sulfide resin composition (Y) of Example 7.

[Example 8]
The recycled material (X1), the virgin PPS resin composition (V1) used in Reference Example 1 described later, and the compound (A1) were dry-blended in the content ratios shown in Table 2. This was fed into a twin-screw extruder with a cylinder temperature of 320°C and melt-kneaded to obtain pellets (repellet) of the recycled polyarylene sulfide resin composition (Y) of Example 8.

[Comparative Example 1]
Pellets (repellet) of the recycled polyarylene sulfide resin composition of Comparative Example 1 were obtained in the same manner as in Examples 1 to 6, except that compound (A1) or (A2) was not added.

[Comparative Examples 2 and 3]
The recycled material (X1) and the compound (A1) were dry-blended in the content ratio shown in Table 2. This was put into a twin-screw extruder with a cylinder temperature of 320°C and melt-kneaded to obtain pellets (repellet) of the recycled polyarylene sulfide resin composition (Y) of Comparative Examples 2 and 3.

[Reference Examples 1 and 2]
In Reference Examples 1 and 2, the following virgin polyarylene sulfide resin compositions (virgin materials) were used.
Virgin PPS resin composition (V1): 65% by mass of polyphenylene sulfide resin (manufactured by Kureha Corporation, Fortron (registered trademark) KPS), 30% by mass of glass fiber, and 4% by mass of elastomer (composition: E-GMA-MA (glycidyl methacrylate content: 3% by mass)), the remainder being a resin composition containing additives).
Virgin PPS resin composition (V2): 69% by mass of polyphenylene sulfide resin (manufactured by Kureha Corporation, Fortron (registered trademark) KPS), 30% by mass of glass fiber, and the remaining amount of a resin composition containing additives (not containing an elastomer component)

[Mold release resistance]
The release resistance was measured by the following method using the repellets of the Examples and Comparative Examples and the virgin materials of Reference Examples 1 and 2. The results are shown in Tables 1 and 2. When the release resistance is 410 N or less, the release property is excellent, when it is 405 N or less, the release property is even better, and when it is 400 N or less, the release property is even better.
A double cylindrical molded article as shown in FIG. 1 was molded under the following conditions using an injection molding machine, and the force required to eject the molded piece (test piece) from the mold was measured. The measured value was taken as the mold release resistance value.
Pressure sensor: "Indirect type in-mold sensor" (model: 9221A) manufactured by Kistler Japan Ltd.
Injection molding machine: Toshiba Machine Co., Ltd. "EC60Ni1.5A"
Cylinder temperature: 320°C
Injection time: 12 seconds Cooling time: 45 seconds Mold temperature: 150°C

[Evaluation of Mold Adhesion]
The repellets of the Examples and Comparative Examples and the virgin materials of Reference Examples 1 and 2 were used to measure the amount of material adhering to the die by the following method. The results are shown in Tables 1 and 2.
A nested mold with removable vent and cavity parts was used. Using each repellet and the virgin material of the reference example, molded bodies having the dimensions and shape shown in Figure 2 were continuously molded for 4 hours (1000 times) using the following injection molding machine and conditions. The total weight of the vent and cavity parts removed from the mold was measured before and after the continuous molding. The change in the total weight of the vent and cavity parts before and after the continuous molding was calculated as the weight (μg) of the matter adhering to the mold.
Injection molding machine: FANUC ROBOSHOT S2000i30A
Cylinder temperature: 340°C
Injection time: 2 seconds Cooling time: 10 seconds Mold temperature: 140°C
When the amount of mold adhesion is 100 μg or less, there is an effect of suppressing mold deposits, when it is 90 μg or less, there is an excellent effect of suppressing mold deposits, and when it is 80 μg or less, there is an even better effect of suppressing mold deposits.

As shown in Tables 1 and 2, the recycled polyarylene sulfide resin composition (Y) of Examples 1 to 6 containing 100 parts by mass of the recycled material (X1) or (X2) and 0.1 to 3.0 parts by mass of the compound (A1) or (A2) has a release resistance of 410 N or less and has excellent release properties.
Comparing Example 2 with Example 4, when using a recycled material (X1) containing an elastomer having a reactive functional group, by using as compound (A) a compound (A) containing an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, it is possible to achieve even better releasability with a release resistance of 400 N or less.

As shown in Examples 5 and 6, when a recycled material (X2) that does not contain an elastomer having a reactive functional group is used, the release resistance is 270 N or less in both cases where compound (A) contains a fatty acid ester and where it contains an olefin resin with a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, and even better release properties can be achieved.

Comparing Examples 1 to 4 with Reference Example 1, and Examples 5 and 6 with Reference Example 2, it was found that the recycled raw materials (X1) and (X2) in Examples 1 to 6 have a mold release resistance that is equal to or less than that of virgin materials, and can be molded with good mold release properties that are equal to or greater than that of virgin materials.

In contrast, the recycled polyarylene sulfide resin of Comparative Example 1 has a release resistance of more than 410 N, and has poor release properties.

Comparing Example 7 with Comparative Example 1, it was found that by adding compound (A1) to a virgin PPS resin composition in an amount within the specified range, it was possible to achieve excellent releasability, with a release resistance of 410 N or less, even without adding compound (A1) when producing recycled pellets.

Comparing Example 8 with Comparative Example 1, it was found that by blending recycled material with virgin material, it was possible to achieve excellent demolding performance with a demolding resistance of 410 N or less. In addition, the amount of material adhering to the mold could be reduced.

As shown in Tables 1 and 2, the recycled polyarylene sulfide resin compositions (Y) of Examples 1 to 8 had mold deposits of 80 g or less, and were more effective at suppressing mold deposits. In contrast, the recycled polyarylene sulfide resin of Comparative Example 3 had mold deposits of more than 100 g, resulting in the generation of a large amount of mold deposits.

The recycled polyarylene sulfide resin composition (Y) of this embodiment has excellent mold releasability, and can therefore be suitably used as resin pellets for injection molding or extrusion molding, and has industrial applicability.

Claims (13)

Recycled polyarylene sulfide resin composition (Y) containing 100 parts by mass of recycled material (X) containing polyarylene sulfide resin, and a total of 0.1 to 3.0 parts by mass of compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound. The recycled polyarylene sulfide resin composition (Y) according to claim 1, wherein the recycled material (X) contains an elastomer having a reactive functional group in an amount of 1 mass% or more based on the total amount of the recycled material (X). The recycled polyarylene sulfide resin composition (Y) according to claim 1 or 2, wherein the recycled material (X) includes an elastomer containing structural units derived from an α-olefin and structural units derived from a glycidyl ester of an α,β-unsaturated acid. The recycled polyarylene sulfide resin composition (Y) according to claim 1 or 2, wherein the recycled material (X) contains an elastomer having a reactive functional group, and the compound (A) contains (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in an amount of 95 mass% or more relative to the total amount of the compound (A). The recycled polyarylene sulfide resin composition (Y) according to claim 1, wherein the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass% relative to the total amount of the recycled material (X). A method for producing a recycled polyarylene sulfide resin composition (Y), comprising melt-kneading 100 parts by mass of a recycled material (X) containing a polyarylene sulfide resin with a total of 0.1 to 3.0 parts by mass of a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound. Prior to the melt-kneading, a compound (A) is selected,
Selecting the compound (A),
When the recycled material (X) contains 1% by mass or more of an elastomer having a reactive functional group based on the total amount of the recycled material (X), (A-1) select a compound (A) containing an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C in a total amount of 95% by mass or more based on the total amount of the compound (A);
When the recycled material (X) does not contain an elastomer having a reactive functional group, or the content of the elastomer having a reactive functional group is less than 1 mass% relative to the total amount of the recycled material (X), a compound (A) containing at least one selected from (A-1) an olefin resin having a melt viscosity at 140°C of 0.1 to 8.0 Pa·s, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound in a total amount of 95 mass% or more relative to the total amount of the compound (A) is selected. A polyarylene sulfide resin composition (Z) comprising the recycled polyarylene sulfide resin composition (Y) according to claim 1 or 2 and a virgin polyarylene sulfide resin or a virgin polyarylene sulfide resin composition (V). The polyarylene sulfide resin composition (Z) according to claim 8, wherein the content of the recycled polyarylene sulfide resin composition (Y) is 50 mass% or more based on the total amount of the recycled polyarylene sulfide resin composition (Y) and the virgin polyarylene sulfide resin or virgin polyarylene sulfide resin composition (V). A method for improving the releasability of a polyarylene sulfide resin-containing recycled material (X) during recycling, the method comprising melt-kneading the polyarylene sulfide resin-containing recycled material (X) with a compound (A) containing one or more selected from (A-1) an olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) a fatty acid derivative, and (A-3) a silicone-based compound, such that the total amount of compound (A) is 0.1 to 3.0 parts by mass per 100 parts by mass of the polyarylene sulfide resin-containing recycled material (X). The method for improving releasability according to claim 10, wherein the recycled material (X) containing polyarylene sulfide resin is a pulverized product or a repellet of an article containing polyarylene sulfide resin. 　The use of compound (A) to improve the releasability of recycled material (X) containing polyarylene sulfide resin during recycling, comprising melt-kneading recycled material (X) containing polyarylene sulfide resin with compound (A) containing one or more selected from (A-1) olefin resin having a melt viscosity of 0.1 to 8.0 Pa·s at 140°C, (A-2) fatty acid derivative, and (A-3) silicone-based compound, such that the total amount of compound (A) is 0.1 to 3.0 parts by mass per 100 parts by mass of recycled material (X) containing polyarylene sulfide resin. The use of the compound (A) according to claim 12, wherein the recycling material (X) containing the polyarylene sulfide resin is a ground product or a repellet of an article containing the polyarylene sulfide resin.

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