Polyarylene sulfide resin composition, method for producing same, molded product, and method for suppressing colored foreign matter in resin composition

Abstract

Provided are: a polyarylene sulfide resin composition in which the generation and contamination of colored foreign matter are suppressed; a method for producing the same; and a molded product. Also provided is a method for suppressing colored foreign matter in a polyarylene sulfide resin composition.　The polyarylene sulfide resin composition comprises: 100 parts by mass of a polyarylene sulfide resin (A); and 0.03-5 parts by mass of a colored foreign matter inhibitor (B) including at least one selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate and basic zinc carbonate.

Description

Polyarylene sulfide resin composition, method for producing the same, molded article, and method for suppressing colored foreign matter in the resin composition.

[0001] This disclosure relates to a polyarylene sulfide resin composition, a method for producing the same, a molded article, and a method for suppressing colored foreign matter in the resin composition.

[0002] Polyarylene sulfide resins are widely used in electrical and electronic equipment components, automotive parts, and chemical equipment components due to their excellent heat resistance, mechanical properties, chemical resistance, dimensional stability, and flame retardancy. On the other hand, Patent Document 1 describes a heat-resistant aging resin composition containing polyarylene sulfide resin and a heat aging inhibitor.

[0003] Japanese Patent Publication No. 2014-210914

[0004] A known method for producing polyarylene sulfide resin compositions involves melting and kneading the material using an extruder. However, if the extrusion time is long, the polyarylene sulfide resin composition tends to accumulate in the dead space inside the extruder. The accumulated polyarylene sulfide resin composition is easily oxidized and decomposed by the air brought into the extruder along with the material, and when heat is applied to the decomposition products, they tend to carbonize and produce black or other colored foreign matter (black speck). If the generated black speck is mixed into the resin composition, the appearance of the molded product may be impaired, and in the case of small molded products, the physical properties of the molded product may deteriorate. Since the number of black speck tends to increase with longer extrusion times, in order to suppress the generation and inclusion of black speck, it was necessary to divide the extrusion time into short intervals and take measures such as cleaning the extruder each time.

[0005] The first object of this disclosure is to provide a polyarylene sulfide resin composition in which the generation and inclusion of colored foreign matter are suppressed, a method for producing the same, and a molded article. The second object of this disclosure is to provide a method for suppressing colored foreign matter in a polyarylene sulfide resin composition.

[0006] This disclosure includes the following embodiments: (1) A polyarylene sulfide resin composition comprising 100 parts by mass of a polyarylene sulfide resin (A) and 0.03 to 5 parts by mass of a coloring foreign matter inhibitor (B) comprising one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate. (2) A molded article comprising the polyarylene sulfide resin composition described in (1) above. (3) A method for producing a polyarylene sulfide resin composition, comprising blending a coloring foreign matter inhibitor (B) comprising one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). (4) A method for suppressing discolored foreign matter in a polyarylene sulfide resin composition, comprising blending one or more zinc-based compounds selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

[0007] This disclosure provides a polyarylene sulfide resin composition in which the generation and inclusion of colored foreign matter are suppressed, a method for producing the same, and a molded article. Furthermore, this disclosure provides a method for suppressing colored foreign matter in a polyarylene sulfide resin composition.

[0008] One embodiment of this disclosure will be described in detail below, but the scope of this disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of this disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. If multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. The lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. If multiple numerical ranges are given for multiple parameters, any numerical range can be adopted for each parameter and combined as desired. The expression "X to Y" indicating a numerical range means "X or greater and Y or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0009] [Polyarylene Sulfide Resin Composition] The polyarylene sulfide resin composition according to this embodiment (hereinafter also simply referred to as "resin composition") comprises 100 parts by mass of polyarylene sulfide resin (A) and 0.03 to 5 parts by mass of a coloring foreign matter inhibitor (B) containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate. By including a predetermined amount of the coloring foreign matter inhibitor (B), a polyarylene sulfide resin composition can be obtained in which the generation and mixing of coloring foreign matter are suppressed even when the extrusion time is long. As a result, molded products with a good appearance can be manufactured with high productivity. Although the mechanism is not yet clear, it is thought that, as a non-limiting mechanism, zinc-based compounds such as zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate act on the main chain of polyarylene sulfide resin (A) (for example, by the coordination of zinc cations to the main chain of polyarylene sulfide resin (A)), making the retained polyarylene sulfide resin composition less susceptible to oxidation even when it comes into contact with air introduced into the extruder.

[0010] Here, Patent Document 1 proposes that potassium hydroxide, sodium hydroxide, sodium acetate, calcium hydroxide, potassium acetate, lithium hydroxide, zinc hydroxide, zinc acetate, magnesium hydroxide, zinc oxide, zinc carbonate, and basic zinc carbonate have properties (thermal aging prevention properties) that can suppress the decrease in tensile strength, tensile elongation, and resistivity, suppress the increase in dielectric constant, suppress discoloration, and suppress the generation of gases, even when molded articles are heated for a long period of time (heat aging). However, it does not describe suppressing the oxidation of the resin composition in a molten state during the manufacture of the resin composition, suppressing the generation of colored foreign matter during the manufacture of the resin composition, and / or suppressing the incorporation of colored foreign matter into the resin composition.

[0011] <Polyarylene sulfide resin (A)> Polyarylene sulfide resin is a resin having repeating units represented by the following general formula (I): -(Ar-S)- ... (I) (where Ar represents an arylene group.)

[0012] The arylene group is not particularly limited, but examples include p-phenylene group, m-phenylene group, o-phenylene group, substituted phenylene group, p,p'-diphenylene sulfone group, p,p'-biphenylene group, p,p'-diphenylene ether group, p,p'-diphenylene carbonyl group, naphthalene group, etc. The polyarylene sulfide resin can be a homopolymer using the same repeating unit as represented by the above general formula (I), or a copolymer containing different types of repeating units.

[0013] As a homopolymer, one having a p-phenylene group as the arylene group and consisting of repeating p-phenylene sulfide groups is preferred. This is because homopolymers with repeating p-phenylene sulfide groups have extremely high heat resistance and exhibit high strength, high rigidity, and high dimensional stability over a wide temperature range. By using such a homopolymer, a molded article with excellent physical properties can be obtained.

[0014] As the copolymer, any combination of two or more different arylene sulfide groups from among the arylene groups containing the above-mentioned arylene group 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 article 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. Note that the polyarylene sulfide resin having a phenylene sulfide group is polyphenylene sulfide resin (PPS resin).

[0015] Polyarylene sulfide resin (A) is generally known to have a molecular structure that is substantially linear and does not have branching or crosslinking structures, or a structure that has branching or crosslinking structures, depending on the manufacturing method, but in this embodiment, it may have either structure. Polyarylene sulfide resin (A) having a linear structure is generally prone to appearing white or milky white, so if colored foreign matter such as black speck occurs and is mixed into the resin composition, the foreign matter is easily visible and the appearance of the molded product is more likely to deteriorate. However, according to the resin composition of this embodiment, the generation and mixing of colored foreign matter is suppressed, so even when using polyarylene sulfide resin (A) having a linear structure, deterioration of the appearance of the molded product is less likely to occur. In one embodiment, polyarylene sulfide resin (A) may have a linear structure.

[0016] The melt viscosity of the polyarylene sulfide resin (A) is not particularly limited, but at 310°C and a shear rate of 1200 sec. －１ The melt viscosity measured is preferably 600 Pa·s or less, and among those in the range of 5 to 300 Pa·s, it is particularly preferred because it has an excellent balance of mechanical properties and fluidity.

[0017] The method for producing the polyarylene sulfide resin (A) is not particularly limited and can be produced by conventionally known production methods. When obtaining a high molecular weight polyarylene sulfide resin, for example, it can be produced by synthesizing a low molecular weight polyarylene sulfide resin and then polymerizing it at high temperature in the presence of a known polymerization aid to increase its molecular weight.

[0018] In one embodiment, the content of polyarylene sulfide resin (A) in the resin composition is preferably 45% by mass or more, more preferably 50 to 99% by mass, may be 55 to 80% by mass, or 60 to 75% by mass, based on the resin composition (100% by mass). By setting the content of polyarylene sulfide resin (A) in the resin composition to 45% by mass or more, the excellent physical properties of polyarylene sulfide resin (A) are more easily expressed. In one embodiment, the content of polyarylene sulfide resin (A) in the thermoplastic resin contained in the resin composition is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, based on the total amount of thermoplastic resin (100% by mass). In one embodiment, the thermoplastic resin contained in the resin composition may consist only of polyarylene sulfide resin. In one embodiment, if the resin composition includes an elastomer as another component described later, the total amount of the polyarylene sulfide resin (A) and the elastomer is preferably 80 to 100% by mass, and more preferably 90 to 100% by mass, of the thermoplastic component (100% by mass) contained in the resin composition.

[0019] <Colored Foreign Matter Inhibitor (B)> "Colored foreign matter inhibitor" means a compound that has the effect of reducing the number of colored foreign matter, such as black, contained in the resin composition. In one embodiment, the resin composition containing the colored foreign matter inhibitor (B) has fewer colored foreign matter than the resin composition without the colored foreign matter inhibitor (B). In one embodiment, the colored foreign matter inhibitor (B) can suppress the generation of colored foreign matter during the manufacturing of the resin composition. In one embodiment, the "colored foreign matter" has a color (or brightness) different from the color (or brightness) of the polyarylene sulfide resin (A). In one embodiment, the colored foreign matter has a brightness (L) different from that of the polyarylene sulfide resin (A). ＊ The value is low. In one embodiment, the colored foreign matter is dark in color. In one embodiment, the colored foreign matter may be black speck. In this case, the colored foreign matter inhibitor (B) is also called a black speck inhibitor.

[0020] The coloring foreign matter inhibitor (B) contains one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate. From the viewpoint of more easily suppressing the generation of coloring foreign matter, the coloring foreign matter inhibitor (B) preferably contains one or more selected from the group consisting of zinc oxide and zinc carbonate, and from the viewpoint of compound stability, it is more preferable to contain zinc oxide.

[0021] The content of the coloring foreign matter inhibitor (B) is 0.03 to 5 parts by mass, preferably 0.05 to 1 part by mass, and more preferably 0.1 to 0.5 parts by mass, per 100 parts by mass of the polyarylene sulfide resin (A). By setting the content of the coloring foreign matter inhibitor (B) to 0.03 to 5 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A), a polyarylene sulfide resin composition in which the generation and mixing of coloring foreign matter are suppressed is easily obtained. In one embodiment, from the viewpoint of suppressing the generation and mixing of coloring foreign matter with a smaller amount, the content of the coloring foreign matter inhibitor (B) may be 0.03 to 0.3 parts by mass, 0.03 to 0.28 parts by mass, 0.04 to 0.2 parts by mass, 0.04 to 0.18 parts by mass, or 0.05 to 0.16 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). In one embodiment, the content of the coloring foreign matter inhibitor (B) may be 0.14 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A), and this may be set as the upper or lower limit within each of the numerical ranges described above.

[0022] Average particle size of coloring foreign matter inhibitor (B) (Volume-based cumulative 50% diameter D) ５０ The average particle size of the colored foreign matter inhibitor (B) is not limited and may be appropriately selected depending on availability and the intended use of the molded product. In one embodiment, the average particle size of the colored foreign matter inhibitor (B) may be 0.1 to 20 μm. In one embodiment, when the colored foreign matter inhibitor (B) contains zinc oxide, the average particle size is preferably 0.1 to 2.0 μm, more preferably 0.2 to 1.5 μm, and even more preferably 0.3 to 1.0 μm, from the viewpoint of easily increasing the light transmittance of the molded product. In one embodiment, when the colored foreign matter inhibitor (B) contains zinc carbonate, the average particle size may be, for example, 10 to 20 μm, 12 to 18 μm, or 13 to 15 μm, from the viewpoint of availability. Average particle size (volume-based cumulative 50% diameter D ５０ ) can be measured by laser diffraction scattering.

[0023] <Inorganic Filler (C)> The resin composition may, if necessary, contain an inorganic filler (C) from the viewpoint of improving mechanical strength. Note that the term "inorganic filler (C)" does not include zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate.

[0024] The shape of the inorganic filler (C) is not limited and may include one or more selected from fibrous inorganic fillers, plate-like inorganic fillers, and granular inorganic fillers. The inorganic filler may be used alone or two or more types may be used in combination.

[0025] In this embodiment, "fibrous" refers to a shape with a diameter ratio of 1 to 6 and an average fiber length (cut length) of 0.01 to 5 mm. "Plate-like" refers to a shape with a diameter ratio greater than 4 and an aspect ratio of 1 to 500. "Granular" refers to a shape with a diameter ratio of 1 to 4 and an aspect ratio of 1 to 2 (including spherical). All shapes are the initial shapes (shapes before melting and kneading). The diameter ratio is defined as "the major axis of a cross section perpendicular to the longitudinal direction (the longest straight-line distance of the cross section) / the minor axis of the cross section (the longest straight-line distance perpendicular to the major axis)." The aspect ratio is defined as "the longest straight-line distance in the longitudinal direction / the minor axis of a cross section perpendicular to the longitudinal direction (the longest straight-line distance perpendicular to the longest straight-line distance in the cross section)." Both the diameter ratio and the aspect ratio can be calculated using a scanning electron microscope and image processing software. Furthermore, the average fiber length (cut length) can be the manufacturer's value (the value published by the manufacturer in their catalog, etc.).

[0026] As fibrous inorganic fillers, any fibrous inorganic filler with a cross-sectional shape perpendicular to the longitudinal direction that is circular, approximately circular, oblong, elliptical, semicircular, cocoon-shaped, rectangular, or similar can be used, and milled fibers obtained by crushing fibrous inorganic fillers can also be used. Circular, approximately circular, oblong, and elliptical cross-sectional shapes perpendicular to the longitudinal direction are particularly preferred. Note that "cocoon-shaped" refers to an oblong shape where the area near the center along the longitudinal direction is indented inward.

[0027] As materials for fibrous inorganic fillers, there are mineral fibers such as glass fibers, carbon fibers, zinc oxide fibers, titanium oxide fibers, wollastonite, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, etc., and metal fibrous substances such as stainless steel fibers, aluminum fibers, titanium fibers, copper fibers, brass fibers, etc. It is preferable to use one or more of these. Among them, it is more preferable to contain glass fibers.

[0028] From the viewpoint of further enhancing mechanical properties, the cross-sectional area perpendicular to the longitudinal direction of the fibrous inorganic filler is preferably 15 μm ２ or more and 2000 μm ２ or less in the initial shape (the shape before melt-kneading), more preferably 60 μm ２ or more and 500 μm ２ or less, and even more preferably 75 μm ２ or more and 300 μm ２ or less. The "cross-sectional area perpendicular to the longitudinal direction" means the area of the surface perpendicular to the longitudinal direction of the fibrous inorganic filler. The "cross-sectional area" can be measured using a scanning electron microscope and image processing software. When the cross-sectional shape perpendicular to the longitudinal direction is circular, substantially circular, oval, or elliptical, the value obtained by multiplying the value obtained by dividing the longest straight-line distance of the cross-section of the fibrous inorganic filler measured using a scanning electron microscope and image processing software by 2 and the value obtained by dividing the shortest straight-line distance by 2, and then multiplying by the value of the circumference ratio π can be used.

[0029] The average fiber length of the fibrous inorganic filler is not particularly limited, but considering the mechanical properties and molding processability of the molded body, etc., the average fiber length (cut length) in the initial shape is preferably 0.01 to 5 mm, more preferably 0.05 to 4 mm, even more preferably 0.1 to 3.5 mm, and particularly preferably 0.5 to 3 mm. Hollow fibers can also be used for the fibrous inorganic filler for the purpose of reducing the specific gravity of the resin composition, etc. The average fiber length is as described above.

[0030] Examples of plate-shaped inorganic fillers include glass flakes, talc (plate-shaped), mica, kaolin, clay, alumina, and various metal foils, and may contain one or more selected from these.

[0031] Average particle size of plate-shaped inorganic filler (volume-based cumulative 50% diameter D) ５０ The particle size (D) in its initial shape (shape before melting and kneading) is preferably 10 μm or more and 1000 μm or less, and more preferably 30 μm or more and 800 μm or less. ５０ ) can be measured by laser diffraction scattering.

[0032] Examples of granular inorganic fillers include carbon black, silica, quartz powder, glass beads, glass powder, talc (granular), silicates such as calcium silicate, aluminum silicate, and diatomaceous earth, metal oxides such as iron oxide, titanium oxide, and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and other materials such as silicon carbide, silicon nitride, boron nitride, and various metal powders, and may contain one or more selected from these.

[0033] Average particle size of granular inorganic filler (volume-based cumulative 50% diameter D) ５０ The particle size (D) in its initial shape (shape before melting and kneading) is preferably 0.1 μm or more and 50 μm or less, more preferably 1 μm or more and 45 μm or less, and even more preferably 10 μm or more and 40 μm or less. ５０ ) can be measured by laser diffraction scattering.

[0034] The content of the inorganic filler (C) is preferably more than 0 part by mass and 350 parts by mass or less, more preferably 5 to 200 parts by mass, still more preferably 10 to 150 parts by mass, particularly preferably 15 to 100 parts by mass, and may be 20 to 80 parts by mass, may be 25 to 70 parts by mass, may be 25 to 60 parts by mass, or may be 30 to 50 parts by mass with respect to 100 parts by mass of the polyarylene sulfide resin (A). By including the inorganic filler (C) at a content of more than 0 part by mass and 350 parts by mass or less with respect to 100 parts by mass of the polyarylene sulfide resin (A), the mechanical strength can be further enhanced.

[0035] <Silane compound (D)> The resin composition preferably contains a silane compound (D). By including the silane compound (D), the mechanical strength tends to be higher. Also, the generation of flash during molding is likely to be suppressed.

[0036] As the silane compound (D), an alkoxysilane compound is preferable. Examples thereof include alkoxysilane compounds such as epoxyalkoxysilane, aminoalkoxysilane, vinylalkoxysilane, and mercaptoalkoxysilane, and it is preferable that one or more of these are used. The number of carbon atoms of the alkoxy group is preferably 1 to 10, particularly preferably 1 to 4.

[0037] Examples of the epoxyalkoxysilane include γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and the like.

[0038] Examples of the aminoalkoxysilane include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-diallylaminopropyltrimethoxysilane, γ-diallylaminopropyltriethoxysilane, and the like.

[0039] Examples of vinylalkoxysilanes include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, and the like.

[0040] Examples of mercaptoalkoxysilanes include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and the like.

[0041] Among these, epoxyalkoxysilanes and aminoalkoxysilanes are preferred, and particularly preferred is γ-aminopropyltriethoxysilane.

[0042] The content of the silane compound (D) is preferably 0.1 to 10 parts by mass, more preferably 0.1 part by mass or more and 1.3 parts by mass or less, still more preferably 0.2 part by mass or more and 1.0 part by mass or less, and even more preferably 0.2 part by mass or more and 0.9 part by mass or less, based on 100 parts by mass of the polyarylene sulfide resin (A). By including the silane compound (D) in a content of 0.1 to 10 parts by mass based on 100 parts by mass of the polyarylene sulfide resin (A), the mechanical strength is more likely to be higher. Also, the generation of flash during molding is likely to be suppressed.

[0043] <Other Additives> The resin composition may contain other thermoplastic components as necessary. Examples of other thermoplastic components include other thermoplastic resins other than the polyarylene sulfide resin (A), elastomers, and the like. The other thermoplastic components can be used alone or in combination of two or more.

[0044] Other thermoplastic resins may be any resin that is stable at high temperatures. Examples include aromatic polyesters composed of aromatic dicarboxylic acids and diols, or oxycarboxylic acids, such as polyethylene terephthalate and polybutylene terephthalate, polyamides, polycarbonates, ABS, polyphenylene oxide, polyalkyl acrylates, polysulfones, polyethersulfones, polyetherimides, polyetherketones, liquid crystal polymers, and cyclic olefin copolymers. These thermoplastic resins may be used individually or in combination of two or more. The content of other thermoplastic resins may be, for example, 0 to 20% by mass, 1 to 15% by mass, or 5 to 10% by mass in the total resin composition (100% by mass).

[0045] Examples of elastomers include olefin copolymers. Elastomers can be used individually or in combination of two or more. The elastomer content may be 0 to 20% by mass, 0.01 to 15% by mass, or 0.1 to 10% by mass in the total resin composition (100% by mass), from the viewpoint of further improving the heat shock resistance of the molded product and preventing the generation of mold deposits during molding.

[0046] The resin composition may optionally contain polymers and additives such as lubricants, nucleating agents, flame retardants, flame retardant aids, antioxidants, metal deactivators, UV absorbers, stabilizers, plasticizers, pigments, dyes, colorants, antistatic agents, foaming agents, and other resins, to the extent that they do not impair the effects of the present disclosure. The content of the above polymers and additives may be 5% by mass or less of the total mass of the resin composition.

[0047] <Applications> The resin composition according to this embodiment contains polyarylene sulfide resin (A), and therefore has excellent heat resistance, mechanical properties, etc., and can be widely used as a material for electrical and electronic equipment components, automotive parts, chemical equipment parts, etc. In particular, since the generation and inclusion of colored foreign matter are suppressed, it is suitable for manufacturing molded products with excellent appearance.

[0048] [Method for Producing Polyarylene Sulfide Resin Composition] The method for producing the polyarylene sulfide resin composition according to this embodiment includes blending a coloring foreign matter inhibitor (B) containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). Since the polyarylene sulfide resin (A) and the coloring foreign matter inhibitor (B) are blended in predetermined amounts, it is easy to obtain a polyarylene sulfide resin composition in which the generation and mixing of coloring foreign matter are suppressed.

[0049] In one embodiment, the method for producing the polyarylene sulfide resin composition may, if necessary, further include blending the above-mentioned inorganic filler (C), silane compound (D), and other additives with the polyarylene sulfide resin (A) and the coloring foreign matter inhibitor (B). In one embodiment, it is preferable that the method for producing the polyarylene sulfide resin composition further includes blending the inorganic filler (C) in an amount greater than 0 parts by mass and less than or equal to 350 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). In one embodiment, it is preferable that the method for producing the polyarylene sulfide resin composition further includes blending the silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). The timing of blending the coloring foreign matter inhibitor (B) and the timing of blending the inorganic filler (C), silane compound (D), and other additives may be the same or different. The types and content (amounts) of polyarylene sulfide resin (A), coloring foreign matter inhibitor (B), inorganic filler (C), silane compound (D), and other additives, as well as other details, are as described above.

[0050] In one embodiment, the compounding process preferably involves melt-kneading a polyarylene sulfide resin (A) and a coloring foreign matter inhibitor (B) (and optionally an inorganic filler (C), a silane compound (D), and other additives). By melt-kneading the polyarylene sulfide resin (A) and the coloring foreign matter inhibitor (B), moldable pellets with suppressed generation and inclusion of colored foreign matter can be easily produced.

[0051] Melt mixing can generally be carried out using equipment and methods commonly used for preparing resin compositions. Typically, the necessary components are mixed and then melt-mixed using a single-screw or twin-screw extruder. The mixture can then be extruded to form molding pellets.

[0052] Generally, an extruder cylinder is equipped with a screw, which has a feeding section, a plasticizing section, and a kneading section running from upstream to downstream. A hopper for supplying raw materials is provided at the upstream end of the cylinder, and a die is connected to the downstream end. The feeding section transports the raw materials supplied into the cylinder in the extrusion direction (downstream direction). Specifically, a conveying screw element composed of forward flights is used, and the raw materials are transported in the extrusion direction by rotating the screw. The plasticizing section melts the raw materials sufficiently by applying shear force to them and generating heat. A screw element with plasticizing capacity (the ability to melt resin) is used in the plasticizing section. The kneading section thoroughly kneads the molten raw materials, mixing them more uniformly. Similar to the plasticizing section, a screw element capable of applying compressive stress, shear stress, etc., to the molten raw materials can also be used in the kneading section. Furthermore, since the plasticizing section and the kneading section are usually connected with a conveying screw element in between, the plasticizing section and the kneading section can be clearly distinguished. In addition, the extruder may have a side feed port for separately adding some components. The side feed port is generally attached to the connection between the hopper and the upper end of the extruder. In one embodiment, melt kneading may include supplying some components into the extruder from the side feed port. In one embodiment, for example, a polyarylene sulfide resin (A), a coloring foreign matter inhibitor (B), a silane compound (D) if necessary, and other additives may be dry blended and then supplied from the hopper into the extruder, while an inorganic filler (C) may be separately supplied into the extruder from the side feed port of the extruder.

[0053] When some materials, such as inorganic fillers (C), are supplied from the side feed port of the extruder, more air is more likely to be introduced into the extruder than when materials are supplied only from the hopper. In that case, the polyarylene sulfide resin composition becomes more susceptible to oxidation, and discolored foreign matter is more likely to occur. However, according to the polyarylene sulfide resin composition of this embodiment, even when some materials are added from the side feed port, a polyarylene sulfide resin composition can be obtained in which the generation and inclusion of discolored foreign matter are suppressed.

[0054] The melt-kneading process preferably involves melt-kneading at a cylinder temperature of the kneading section in the extruder, preferably 160 to 370°C, more preferably 200 to 360°C. The cylinder temperature of the plasticizing section is preferably 300 to 370°C.

[0055] Conventionally, in the manufacturing method of polyarylene sulfide resin compositions, it was necessary to shorten the extrusion time (pellet manufacturing time) and clean the extruder each time in order to suppress the generation of colored foreign matter. However, in the manufacturing method of the resin composition according to this embodiment, since the polyarylene sulfide resin (A) and the colored foreign matter inhibitor (B) are blended in predetermined amounts, the generation of colored foreign matter is easily suppressed, and it is not necessary to shorten the extrusion time. As a result, polyarylene sulfide resin compositions and their pellets with suppressed colored foreign matter contamination can be manufactured with high productivity.

[0056] [Molded Article] The molded article according to this embodiment contains the polyarylene sulfide resin composition described above. Because it contains the polyarylene sulfide resin composition described above, the generation and inclusion of colored foreign matter is suppressed, and the appearance is excellent. In one embodiment, the molded article has suppressed deterioration of physical properties due to the generation and inclusion of colored foreign matter. The size and shape of the molded article are not limited and can be set as appropriate according to the application.

[0057] The method for manufacturing the molded product is not limited, and the product can be manufactured by molding a molding pellet containing the above-mentioned resin composition using generally known molding methods for thermoplastic resins, such as injection molding, extrusion molding, vacuum molding, and compression molding.

[0058] In one embodiment, the molded product is a sheet manufactured by the following method, in which the number of blackish foreign objects visible to the naked eye when white light is irradiated from one side of the sheet and the entire sheet is observed with the light transmitted to the opposite side is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and particularly preferably less than 3. (Method for manufacturing the sheet) The material is put into a twin-screw extruder with a cylinder temperature of 320°C, and while melting and kneading, it is extruded at a discharge rate of 30 kg / hr and a screw rotation speed of 250 rpm, after which the screw rotation is stopped and the material is left to stand for 1 hour to obtain pellets. The obtained pellets are set in a hot press machine and heated at 320°C to produce a sheet of 150 mm × 150 mm × 0.3 mm thick.

[0059] [Method for suppressing colored foreign matter] The method for suppressing colored foreign matter according to this embodiment is a method for suppressing colored foreign matter in a polyarylene sulfide resin composition, and includes blending a zinc-based compound containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). Since the polyarylene sulfide resin (A) and the predetermined zinc-based compound are blended in predetermined amounts, the generation and mixing of colored foreign matter can be suppressed regardless of the length of the extrusion time (or melt-kneading time). The zinc-based compound used in this embodiment corresponds to the colored foreign matter inhibitor (B) described above.

[0060] In one embodiment, the method for suppressing colored foreign matter may include blending the above-mentioned inorganic filler (C), silane compound (D), and other additives into the polyarylene sulfide resin (A) as needed. In one embodiment, it is preferable that the method for suppressing colored foreign matter further includes blending the inorganic filler (C) in an amount greater than 0 parts by mass and less than or equal to 350 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). In one embodiment, it is preferable that the method for suppressing colored foreign matter further includes blending the silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). The timing of blending the zinc-based compound (colored foreign matter inhibitor (B)) and the timing of blending the inorganic filler (C), silane compound (D), and other additives may be the same or different. The types, content (amount) and other details of the polyarylene sulfide resin (A), inorganic filler (C), silane compound (D), and other additives are as described above. The above description regarding the type, content (amount) and other details of the coloring foreign matter inhibitor (B) also applies to the zinc-based compound in this embodiment.

[0061] In one embodiment, the compounding process preferably involves melt-kneading a polyarylene sulfide resin (A) with a zinc-based compound (and optionally, an inorganic filler (C), a silane compound (D), and other additives). Melt-kneading the polyarylene sulfide resin (A) with the zinc-based compound makes it easier to suppress the inclusion of colored foreign matter in the molding pellets containing the polyarylene sulfide resin (A) and the zinc-based compound. The method, temperature, and other conditions for melt-kneading are as described above.

[0062] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below: [1] A polyarylene sulfide resin composition comprising 100 parts by mass of a polyarylene sulfide resin (A) and 0.03 to 5 parts by mass of a coloring foreign matter inhibitor (B) comprising one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate. [2] The polyarylene sulfide resin composition according to [1], comprising an inorganic filler (C) in an amount exceeding 0 parts by mass and not exceeding 350 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). [3] The polyarylene sulfide resin composition according to [1] or [2], comprising a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A). [4] A molded article comprising the polyarylene sulfide resin composition according to any one of [1] to [3]. [5] A method for producing a polyarylene sulfide resin composition, comprising blending a coloring foreign matter inhibitor (B) containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). [6] The method for producing the composition according to [5], further comprising blending an inorganic filler (C) in an amount exceeding 0 parts by mass and not exceeding 350 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). [7] The method for producing the composition according to [5] or [6], further comprising blending a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). [8] A method for suppressing colored foreign matter in a polyarylene sulfide resin composition, comprising blending one or more zinc-based compounds selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A). [9] The method according to [8], further comprising blending an inorganic filler (C) in an amount exceeding 0 parts by mass and not exceeding 350 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

[10] The method according to [8] or [9], further comprising blending a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

[0063] Each configuration and its combination in each embodiment is an example, and additions, omissions, substitutions, and other modifications can be made as appropriate without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments.

[0064] The present disclosure will be further described below with reference to examples, but these examples will not limit the interpretation of the present disclosure.

[0065] [Materials] The materials used in the examples and comparative examples are as follows: <Polyarylene sulfide resin (A)> PPS: Polyphenylene sulfide resin, manufactured by Kureha Corporation, Fortron® KPS, melt viscosity 130 Pa·s (shear rate 1200 sec －１ (310°C) (Measurement of melt viscosity of PPS resin) The melt viscosity of the above PPS resin was measured as follows: Using a capillary graph manufactured by Toyo Seiki Seisakusho Co., Ltd., a flat die of 1 mmφ × 20 mmL was used as the capillary, with a barrel temperature of 310°C and a shear rate of 1200 sec. －１ The melt viscosity was measured. <Coloring foreign matter inhibitor (B)> Zinc-based compound Zinc oxide: Manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size 0.3 μm Zinc carbonate: Manufactured by Seido Chemical Industry Co., Ltd., average particle size 14 μm Zinc hydroxide: Manufactured by Junsei Chemical Co., Ltd. <Inorganic filler (C)> Glass fiber: Manufactured by Nippon Electric Glass Co., Ltd., chopped strand ECS 03T-747N, cross-section is approximately circular, average fiber diameter 17 μm, average fiber length 3 mm <Silane compound (D)> Silane compound: γ-aminopropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBE-903P <Others> Lubricant: Pentaerythritol stearate, manufactured by NOF Corporation, Unistar (registered trademark) H476 Antioxidant: Tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, manufactured by BASF, IRGANOX 1010

[0066] [Examples 1-7, Comparative Examples 1-2] Using the materials shown in Table 1, dry blends were prepared in the proportions shown in Table 1 and fed into a twin-screw extruder at a cylinder temperature of 320°C (glass fibers were added separately through the side feed port of the extruder). Extrusion was carried out at a discharge rate of 30 kg / hr and a screw rotation speed of 250 rpm while melting and kneading, after which the screw rotation was stopped and the mixture was allowed to stand for 1 hour. After that, extrusion was carried out again to obtain resin composition pellets of the examples and comparative examples. The obtained pellets were set in a hot press and heated at 320°C to produce sheets of 150 mm × 150 mm × 0.3 mm thick.

[0067] [Evaluation] A white LED light source for a stereomicroscope was shone from one side of the obtained sheet, and the entire sheet was observed with the light transmitted to the opposite side. The number of blackish foreign objects (black specks) that could be visually confirmed was counted. The results are shown in Table 1.

[0068]

[0069] As shown in Table 1, the resin compositions of Examples 1 to 7, which contain a predetermined amount of polyarylene sulfide resin (A) and a predetermined zinc-based compound (coloring foreign matter inhibitor (B)), suppress the generation and inclusion of coloring foreign matter more effectively than the resin compositions of Comparative Examples 1 and 2, which do not contain the coloring foreign matter inhibitor (B). As shown in Comparative Example 2, conventional antioxidants cannot suppress the generation and inclusion of coloring foreign matter.

[0070] The resin composition according to this embodiment can be widely used as a material for electrical and electronic equipment components, automotive parts, chemical equipment components, etc., and has industrial applicability.

Claims

1. A polyarylene sulfide resin composition comprising: 100 parts by mass of polyarylene sulfide resin (A); and 0.03 to 5 parts by mass of a coloring foreign matter inhibitor (B) containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate.

2. The polyarylene sulfide resin composition according to claim 1, wherein the inorganic filler (C) is contained in an amount exceeding 0 parts by mass and not exceeding 350 parts by mass per 100 parts by mass of the polyarylene sulfide resin (A).

3. The polyarylene sulfide resin composition according to claim 1 or 2, comprising a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

4. A molded article comprising the polyarylene sulfide resin composition according to claim 1 or 2.

5. A method for producing a polyarylene sulfide resin composition, comprising blending a coloring foreign matter inhibitor (B) containing one or more selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate, in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

6. The manufacturing method according to claim 5, further comprising blending an inorganic filler (C) in an amount greater than 0 parts by mass and less than or equal to 350 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

7. The manufacturing method according to claim 5 or 6, further comprising blending a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

8. A method for suppressing colored foreign matter in a polyarylene sulfide resin composition, comprising blending one or more zinc-based compounds selected from the group consisting of zinc hydroxide, zinc acetate, zinc oxide, zinc carbonate, and basic zinc carbonate in an amount of 0.03 to 5 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

9. The method according to claim 8, further comprising blending an inorganic filler (C) in an amount greater than 0 parts by mass and less than or equal to 350 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

10. The method according to claim 8 or 9, further comprising blending a silane compound (D) in an amount of 0.1 to 10 parts by mass per 100 parts by mass of polyarylene sulfide resin (A).

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