Polyphenylene sulfide resin compositions and their molded articles

Abstract

This invention relates to a polyphenylene sulfide resin composition comprising 100 parts by weight of a poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, 10-200 parts by weight of the poly(p-phenylene sulfide) homopolymer, 100 parts by weight of the total mass of the poly(p-phenylene sulfide) homopolymer and the poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, and 5-150 parts by weight of an inorganic filler. This invention possesses excellent mechanical strength and excellent resistance to damp heat, making it particularly suitable for injection molding into cooling water and antifreeze circulation systems in automobiles and other products that are in prolonged contact with water or other liquids.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more specifically to a polyphenylene sulfide resin composition and its molded articles. Background Technology

[0002] Polyphenylene sulfide (PPS) resin possesses excellent flowability, high temperature resistance, corrosion resistance, flame retardancy, balanced physical and mechanical properties, excellent dimensional stability, and good electrical properties, making it widely used in electrical, electronic, and automotive components. In recent years, with the widespread application of PPS materials in automotive cooling water and antifreeze circulation systems, there is a further demand for superior water resistance and resistance to damp heat.

[0003] In response, Patent Document 1 (Japanese Patent Application Publication No. 2018-141149) discloses a resin composition containing polyphenylene sulfide (PPS) and an inorganic filler, which improves the tensile strength retention rate after hygrothermal treatment by increasing the sodium atom content in the PPS resin to 1000 ppm or more, thereby improving its hygrothermal resistance. However, the increase in the sodium atom content leads to a decrease in the tensile strength of the untreated PPS resin composition.

[0004] Patent document 2 (Japanese Publication No. 2018-123307) discloses a resin composition containing poly(p-phenylene sulfide), an inorganic filler, and an organic nucleating agent. By adding an appropriate amount of organic nucleating agent, the melt cooling crystallization temperature (Tc) of the poly(p-phenylene sulfide) resin is increased. mc This process reduces and homogenizes the crystal regions of the polyphenylene sulfide resin, thereby improving the water pressure resistance of the molded product. However, the PEEK resin added as an organic nucleating agent is more likely to become a foreign substance relative to the main polyphenylene sulfide resin.

[0005] On the other hand, Patent Document 3 (Japanese Patent Application Publication No. 2016-69650) discloses a poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, in which a polymer with lower crystallinity is obtained by copolymerizing m-phenylene sulfide units into the poly(p-phenylene sulfide) molecule, thereby improving the adhesion between the formed film and the metal or resin surface. However, the film stability is poor when not mixed with the poly(p-phenylene sulfide) homopolymer. Furthermore, the strength of the film formed from this poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is lower than that of the poly(p-phenylene sulfide) homopolymer, making it unsuitable for injection molding into cooling water and antifreeze circulation systems in automobiles and other molded products that require a certain strength and are in long-term contact with liquids such as water. Summary of the Invention

[0006] In order to solve the above problems, the inventors, after in-depth research, discovered that when a polyphenylene sulfide resin composition contains (A) poly(p-phenylene sulfide) homopolymer, (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer and (C) inorganic filler in a specific amount, it can not only improve the resistance of the polyphenylene sulfide resin composition to damp heat, but also have higher mechanical strength.

[0007] The present invention also provides a molded article made from the above-described polyphenylene sulfide resin composition. Due to its excellent resistance to damp heat, it is suitable for cooling water and antifreeze circulation systems in automobiles and other components that are in long-term contact with liquids such as water.

[0008] The technical solution of this invention is as follows:

[0009] 1. A polyphenylene sulfide resin composition comprising:

[0010] (A) Poly(p-phenylene sulfide) homopolymer;

[0011] (B) Poly(p-phenylene sulfide)-m-phenylene sulfide copolymer; and

[0012] (C) Inorganic fillers,

[0013] Relative to 100 parts by weight of the (A) poly(p-phenylene sulfide) homopolymer, the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is 10-200 parts by weight;

[0014] The inorganic filler (C) is 5-150 parts by mass relative to 100 parts by mass of the total mass of (A) poly(p-phenylene sulfide) homopolymer and (B) poly(p-phenylene sulfide-m-phenylene sulfide) copolymer.

[0015] 2. The polyphenylene sulfide resin composition according to 1 above, wherein in the (B) poly(p-phenylene sulfide-m-phenylene sulfide) copolymer, the content of m-phenylene sulfide units relative to the total mass of phenylene sulfide units in the copolymer is 5-25 wt%.

[0016] 3. The polyphenylene sulfide resin composition according to 1 above, wherein the content of the m-phenylene sulfide unit contained in the (B) polyphenylene sulfide-m-phenylene sulfide copolymer is 1-13 wt% relative to the total mass of the phenylene sulfide units in the (A) polyphenylene sulfide homopolymer and the (B) polyphenylene sulfide-m-phenylene sulfide copolymer.

[0017] 4. The polyphenylene sulfide resin composition according to 1 above, wherein the (B) poly(p-phenylene sulfide-m-phenylene sulfide) copolymer is a random copolymer.

[0018] 5. The polyphenylene sulfide resin composition according to claim 1 above, wherein, relative to 100 parts by mass of the total mass of the (A) poly(p-phenylene sulfide) homopolymer and the (B) poly(p-phenylene sulfide-m-phenylene sulfide) copolymer, the (C) inorganic filler is 20-110 parts by mass.

[0019] 6. The polyphenylene sulfide resin composition according to 1 above, wherein the inorganic filler (C) is at least one selected from glass fiber, glass sheet, glass microsphere, carbon fiber, calcium carbonate, silica, talc or wollastonite.

[0020] 7. The polyphenylene sulfide resin composition according to claim 1 above, further comprising (D) a silane compound.

[0021] 8. The polyphenylene sulfide resin composition according to 7 above, wherein the (D) silane compound is an alkoxysilane compound containing an epoxy group.

[0022] 9. A molded article, characterized in that it is obtained using the polyphenylene sulfide resin composition described in any one of 1-8 above.

[0023] 10. The molded article as described in 9 above is used in a cooling water and antifreeze circulation system. Detailed Implementation

[0024] The specific embodiments of the present invention are described below:

[0025] 1. (A) Poly(p-phenylene sulfide) homopolymer:

[0026] The (A) poly(p-phenylene sulfide) homopolymer used in this invention is a polymer having repeating units as shown in the following structural formula (I).

[0027]

[0028] The present invention does not have any particular limitation on the structure of the poly(p-phenylene sulfide) homopolymer. A linear poly(p-phenylene sulfide), an acid-crosslinked poly(p-phenylene sulfide), or a branched poly(p-phenylene sulfide) with added trihalomethane functional group reactants can be used. The amount of added trihalomethane functional group reactants is preferably less than 1 wt%.

[0029] The manufacturing method of the polyphenylene sulfide homopolymer used in this invention is not limited. For example, the polyphenylene sulfide homopolymer having the structure of the above-described formula (I) can be prepared by the method for obtaining higher fluidity described in Japanese Patent Publication No. 45-3368 or the method for obtaining lower fluidity described in Japanese Patent Publication No. 52-12240, etc. The difference between the former and the latter lies in whether there is a polymerization aid, an alkali metal carboxylate, in the polymerization system. In the former method, no alkali metal carboxylate is added to the polymerization system, resulting in higher fluidity; while in the latter method, an alkali metal carboxylate is added to the polymerization system, resulting in lower fluidity, which is beneficial to the toughness of the resin. Therefore, polyphenylene sulfide polymers prepared by the two methods can be used in combination to balance the fluidity and toughness of the polyphenylene sulfide resin.

[0030] Furthermore, end-capping the polyphenylene sulfide polymer prepared above can yield polyphenylene sulfide polymers with lower chlorine content. For example, end-capping with 2-mercaptobenzimidazole under alkaline conditions can yield end-capped polyphenylene sulfide homopolymers with lower chlorine content.

[0031] 2. (B) Poly(p-phenylene sulfide)-m-phenylene sulfide copolymer:

[0032] The (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer used in this invention is a copolymer having repeating units as shown in the above-described structural formula (I) and the following structural formula (II).

[0033]

[0034] The poly(p-phenylene sulfide)-m-phenylene sulfide copolymer has low crystallinity and low mechanical strength, making it unsuitable for use alone as a plastic product. However, the inventors have discovered that adding the poly(p-phenylene sulfide)-m-phenylene sulfide copolymer (B) and inorganic filler (C) to the above-mentioned (A) poly(p-phenylene sulfide) homopolymer can improve the humid heat resistance of the (A) poly(p-phenylene sulfide) homopolymer.

[0035] In the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer used in this invention, the content of m-phenylene sulfide units relative to the total mass of phenylene sulfide units in the copolymer is preferably 5-25 wt%. When the content of m-phenylene sulfide units relative to the total mass of phenylene sulfide units in the copolymer is higher than 25 wt%, the melting point and crystallinity of the poly(p-phenylene sulfide)-m-phenylene sulfide copolymer tend to decrease, which is not conducive to its use; its content is further preferably below 20 wt%. When the content of m-phenylene sulfide units relative to the total mass of phenylene sulfide units in the copolymer is lower than 5 wt%, the effect on improving the mechanical properties and damp heat resistance of the composition is limited; its content is further preferably above 10 wt%.

[0036] In particular, for flowability considerations, the copolymer structure of (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer used in this invention is preferably a random copolymer.

[0037] 3. The ratio of component (A) to component (B)

[0038] In this invention, the content of component (B), poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, is 10-200 parts by weight relative to 100 parts by weight of component (A), the poly(p-phenylene sulfide) homopolymer. In this invention, it is necessary to improve the resistance to damp heat while maintaining the mechanical strength of the composition. To achieve this, components (A) and (B) need to be mixed in an appropriate ratio. Preferably, in this invention, component (B) is 20 parts by weight or more, more preferably 30 parts by weight or more, relative to 100 parts by weight of component (A). On the other hand, preferably, the amount of component (B) added is 150 parts by weight or less, more preferably 100 parts by weight or less. When the content of component (B) is less than 10 parts by weight relative to 100 parts by weight of component (A), the resistance to damp heat of the composition is not improved. When the content of component (B) is greater than 200 parts by weight, the mechanical strength of the composition decreases.

[0039] In this invention, the content of m-phenylene sulfide units in the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer relative to the total mass of phenylene sulfide units in the (A) poly(p-phenylene sulfide) homopolymer and the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is preferably 1-13 wt%. When the content of m-phenylene sulfide units in the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is less than 1 wt%, the composition tends to have decreased resistance to damp heat; its content is further preferably 2.5 wt% or more. When the content of m-phenylene sulfide units is greater than 13 wt%, the mechanical strength of the composition tends to decrease; its content is further preferably 11 wt% or less.

[0040] 4. (C) Inorganic packing:

[0041] The aforementioned (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer has low mechanical strength due to its low crystallinity. When no inorganic filler is added, the mechanical strength of the aforementioned (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer decreases relative to the poly(p-phenylene sulfide) homopolymer when the aforementioned (A) poly(p-phenylene sulfide) homopolymer is added. However, the inventors have discovered that the resin composition formed by further adding (C) inorganic filler to the mixture of the aforementioned (A) poly(p-phenylene sulfide) homopolymer and the aforementioned (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer exhibits a particularly high mechanical strength and resistance to damp heat compared to a resin composition containing only (A) poly(p-phenylene sulfide) homopolymer and (C) inorganic filler, or a resin composition containing only (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer and (C) inorganic filler.

[0042] The inorganic filler described in this invention refers to fillers used in resins in the prior art. Examples include glass fiber, carbon fiber, potassium titanate whiskers, zinc whisker oxide, aluminum borate whiskers, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, metal fiber, glass flakes, wollastonite, zeolite, sericite, kaolin, mica, talc, clay, pyrophyllite, bentonite, montmorillonite, lithium montmorillonite, synthetic mica, asbestos, graphite, aluminosilicates, alumina, silicon dioxide, magnesium oxide, zirconium oxide, titanium oxide, iron oxide, calcium carbonate, magnesium carbonate, dolomite, calcium sulfate, barium sulfate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass microspheres, hollow glass microspheres, ceramic beads, boron nitride, silicon carbide, or wollastonite, etc. The inorganic filler can also be a hollow inorganic filler, and furthermore, two or more of these inorganic fillers can be selected and used in combination. The average diameter of the inorganic filler is not particularly limited, but is preferably 0.001-20μm. Within this range, better flowability and better appearance can be obtained.

[0043] Specifically, considering both low molding shrinkage and flowability, and to obtain a high-performance polyphenylene sulfide resin composition, the inorganic filler is preferably at least one of glass fiber or carbon fiber. The glass fiber is not specifically limited and can be any glass fiber used in the prior art. The glass fiber can be chopped strands, coarse sand, abrasive fibers, or other similar shapes. Generally, an average diameter of 5-15 μm is preferred. When using chopped strands, the length is not particularly limited, but a standard 3 mm length suitable for extrusion compounding is preferred. Furthermore, the present invention does not particularly limit the cross-sectional shape of the aforementioned fibrous filler material; any combination of round or flat fibers can be selected.

[0044] On the other hand, in order to obtain a better product appearance, at least one of glass flakes, glass microspheres, hollow glass microspheres, calcium carbonate, silica, talc or wollastonite is preferred.

[0045] 5. Proportion of Component (C)

[0046] In this invention, relative to 100 parts by weight of the total mass of component (A) polyphenylene sulfide homopolymer and component (B) polyphenylene sulfide-m-phenylene sulfide copolymer, the content of component (C) inorganic filler is 5-150 parts by weight. Within this range, the polyphenylene sulfide resin composition of this invention can maintain good flowability, processability, and toughness while possessing good mechanical strength. In this invention, relative to 100 parts by weight of the total mass of components (A) and (B), the amount of component (C) added is preferably 20 parts by weight or more, more preferably 40 parts by weight or more. On the other hand, the amount of inorganic filler (C) added is preferably 110 parts by weight or less, more preferably 80 parts by weight or less.

[0047] 6. (D) Silane compounds

[0048] In this invention, to enhance the adhesion between the resin and the inorganic filler, a (D) silane compound can be further added. The silane compound is preferably an alkoxysilane compound having one or more groups selected from epoxy, amino, isocyanate, hydroxyl, mercapto, and urea groups.

[0049] Specific examples of the above-mentioned alkoxysilane compounds having at least one functional group selected from epoxy, amino, isocyanate, hydroxy, mercapto, and urea groups include alkoxysilane compounds containing epoxy groups such as γ-epoxypropoxypropyltrimethoxysilane, γ-epoxypropoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; alkoxysilane compounds containing mercapto groups such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; alkoxysilane compounds containing urea groups such as γ-ureopropyltriethoxysilane, γ-ureopropyltrimethoxysilane, and γ-(2-ureoethyl)aminopropyltrimethoxysilane; and γ-isocyanate propyltriethoxysilane. Alkoxysilane compounds containing isocyanate groups, such as γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-propylmethyldimethoxysilane, γ-isocyanate-propylmethyldiethoxysilane, γ-isocyanate-propylethyldimethoxysilane, γ-isocyanate-propylethyldiethoxysilane, and γ-isocyanate-propyltrichlorosilane; alkoxysilane compounds containing amino groups, such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; and alkoxysilane compounds containing hydroxyl groups, such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane.

[0050] In this invention, for the sake of adhesion and flowability, the silane compound (D) is preferably 0.01-3 parts by mass relative to 100 parts by mass of the total mass of component (A) polyphenylene sulfide homopolymer and (B) polyphenylene sulfide-m-phenylene sulfide copolymer. By adding a silane compound within the above range, the adhesion between the polyphenylene sulfide resin and the inorganic filler can be enhanced while ensuring the flowability of the polyphenylene sulfide resin composition in this invention. The content of the silane compound is further preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more. At the same time, its content is further preferably 2 parts by mass or less, more preferably 1 part by mass or less.

[0051] In this invention, for the purpose of improving reactivity with polyphenylene sulfide resin, component (D) is preferably an alkoxysilane compound having an epoxy group.

[0052] 7. Other additives

[0053] In addition to components (A) to (D), the polyphenylene sulfide resin composition of the present invention may further include an elastomer, an antioxidant, a release agent (lignite acid and its metal salts, esters, half-esters, stearyl alcohol, stearamide, biuret or polyethylene wax, etc., wherein stearamide is preferred to reduce gas generation during molding), a pigment (cadmium sulfide, phthalocyanine, or colored carbon black masterbatch, etc.), a dye (aniline black, etc.), a crystallizing agent (talc, titanium dioxide, kaolin, clay, etc.), and a plasticizer (octyl-p-hydroxybenzoate, or N- The following agents can be selected and used in combination: butylbenzene sulfonamide, antistatic agents (alkyl sulfate anionic antistatic agents, quaternary ammonium cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, or trimethylammonium glycolide amphoteric antistatic agents), flame retardants (e.g., red phosphorus, phosphate esters, melamine cyanurate, magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, polycarbonate bromide, brominated epoxy resin, or combinations of these brominated flame retardants and antimony trioxide), etc.

[0054] The elastomer may include one or more of the following: olefin-based elastomers, modified olefin-based elastomers, or styrene-based elastomers.

[0055] Examples of olefin-based elastomers include: α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, or isobutene, or polymers or copolymers obtained by polymerizing multiple α-olefins; and copolymers of α-olefins with α,β-unsaturated acids and their alkyl esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, or butyl methacrylate. For superior toughness, polyethylene, polypropylene, ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / methyl acrylate copolymers, ethylene / ethyl acrylate copolymers, ethylene / butyl acrylate copolymers, ethylene / methyl methacrylate copolymers, ethylene / ethyl methacrylate copolymers, and ethylene / butyl methacrylate copolymers are preferred.

[0056] Modified olefin elastomers can be obtained by introducing monomeric components (components containing functional groups) having functional groups such as epoxy groups, anhydride groups, or ionic polymers into the aforementioned olefin elastomers. Examples of such functional group components include: maleic anhydride, itaconic anhydride, citraconic anhydride, intracyclic [2,2,1]5-heptene-2,3-dicarboxylic acid, or intracyclic [2,2,1]5-heptene-2,3-dicarboxylic acid anhydride, etc.; epoxy-containing monomers such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethyl acrylate, glycidyl itaconic acid, or glycidyl citraconic acid, etc.; or monomers containing ionic polymers such as carboxylic acid metal complexes.

[0057] There are no particular limitations on the method for introducing these functional group-containing monomer components. Methods such as copolymerization with components used in the polymerization of the aforementioned olefin-based elastomers, or grafting into the olefin-based (co)polymer using a free radical initiator, are acceptable. The amount of the functional group-containing component introduced relative to all monomers constituting the modified olefin-based elastomer is 0.001-40 mol%, preferably 0.01-35 mol%.

[0058] Particularly useful modified olefin elastomers obtained by introducing monomeric components with functional groups such as epoxy groups, anhydride groups, or ionic polymers into olefin elastomers include: ethylene / propylene-glycidyl methacrylate copolymers ("g" indicates grafting, the same applies below), ethylene / 1-butene-glycidyl methacrylate copolymers, ethylene / glycidyl acrylate copolymers, ethylene / glycidyl methacrylate copolymers, ethylene / methyl acrylate / glycidyl methacrylate copolymers, ethylene / methyl methacrylate / glycidyl methacrylate copolymers, ethylene / propylene-glycidyl anhydride copolymers, ethylene / 1-butene-glycidyl anhydride copolymers, ethylene / methyl acrylate-glycidyl anhydride copolymers, ethylene / ethyl acrylate-glycidyl anhydride copolymers, ethylene / methyl methacrylate-glycidyl anhydride copolymers, ethylene / ethyl methacrylate-glycidyl anhydride copolymers, zinc complexes of ethylene / methacrylate copolymers, magnesium complexes of ethylene / methacrylate copolymers, or sodium complexes of ethylene / methacrylate copolymers, etc.

[0059] From a compatibility perspective, the preferred options are: ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, ethylene / 1-butene-g-maleic anhydride copolymer, or ethylene / ethyl acrylate-g-maleic anhydride copolymer. More preferably, the preferred options are: ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, or ethylene / methyl methacrylate / glycidyl methacrylate copolymer.

[0060] Examples of styrene-based elastomers include styrene / butadiene copolymers, styrene / ethylene / butadiene copolymers, styrene / ethylene / propylene copolymers, and styrene / isoprene copolymers, with styrene / butadiene copolymers being preferred in terms of compatibility.

[0061] Considering both fluidity and toughness, the amount of elastomer added is preferably 0.5-20 parts by mass relative to 100 parts by mass of component (A) and component (B), more preferably 0.8-10 parts by mass, and even more preferably 1-6 parts by mass. In addition, within the scope of not affecting the effect of the present invention, the above-mentioned elastomer can be used in combination in various ways.

[0062] The antioxidant is preferably at least one selected from phenolic antioxidants and phosphorus antioxidants. The combined use of phenolic and phosphorus antioxidants effectively maintains heat resistance and thermal stability; therefore, their combined use is preferred.

[0063] As phenolic antioxidants, hindered phenolic compounds are preferred. Specific examples include: triethylene glycol bis(3-tert-butyl-(5-methyl-4-hydroxybenzyl)propionate, N,N′-hexamethylene bis(3,5-di-tert-butyl-4-hydroxy-hydrogenated cinnamamide), tetra(methylene-3-(3′,5′-di-tert-butyl-4′-hydroxybenzyl)propionate)methane, pentaerythritol tetra(3-(3′,5′-di-tert-butyl)-4′-hydroxybenzyl)propionate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione, 1 1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4′-butylenebis(3-methyl-6-tert-butylphenyl), n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis(2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, or 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, etc. Among them, ester-type hindered polymeric phenols are preferred, specifically tetra(methylene-3-(3′,5′-di-tert-butyl-4′-hydroxybenzyl)propionate)methane, pentaerythritol tetra(3-(3′,5′-di-tert-butyl)-4′-hydroxybenzyl)propionate, or 3,9-bis(2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionoxy)-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, etc.

[0064] Examples of phosphorus-based antioxidants include bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, tetra(2,4-di-tert-butylphenyl)-4,4′-bisphenylphosphite, distearyl pentaerythritol diphosphite, triphenylphosphite, or diethyl 3,5-dibutyl-4-hydroxybenzyl phosphate.

[0065] The amount of antioxidant added is preferably 0.01-3 parts by mass, more preferably 0.05-2 parts by mass, and most preferably 0.1-1 parts by mass relative to 100 parts by mass of components (A) and (B).

[0066] The polyphenylene sulfide resin composition of the present invention has excellent mechanical strength and resistance to damp heat, and is particularly suitable for injection molding into cooling water and antifreeze circulation systems for automobiles and other products that are in long-term contact with liquids such as water.

[0067] The present invention will be further illustrated by specific embodiments below. The following embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0068] Example

[0069] 1. Raw materials for polyphenylene sulfide resin compositions

[0070] Poly(p-phenylene sulfide) homopolymer (p-PPS homopolymer) A-1: ​​Linear PPS resin (weight average molecular weight: 49,000)

[0071] Poly(p-PPS / m-PPS) copolymer B-1: Zhejiang NHU Co., Ltd. 1130F-M1 (10wt% m-phenylene sulfide unit, random copolymer, weight average molecular weight: 52,000) Poly(p-PPS / m-PPS) copolymer B-2: Zhejiang NHU Co., Ltd. 1130F-M2 (20wt% m-phenylene sulfide unit, random copolymer, weight average molecular weight: 58,000) Glass fiber C-1: Nippon Electric Glass Co., Ltd. T-760H (single fiber diameter 10.5μm)

[0072] Calcium carbonate C-2: Calfine KSS-1000 Co., Ltd.

[0073] Silane compound D-1: Dow Chemical Company, XIAMETER TM OFS-6040

[0074] Release agent E-1: PRIME POLYMER, PE7000FB

[0075] Pigment F-1: Carbon Black Masterbatch, Toray Industries, Inc. S771B2

[0076] 2. The test descriptions involved in the examples and comparative examples are as follows.

[0077] 1) Tensile strength test:

[0078] The standard specimens obtained from the examples and comparative examples were injection molded and measured according to ISO 527-1,-2 standard. The tensile rate was 5 mm / min, the distance between the markings was 50 mm, and the distance between the fixtures was 115 mm. The average value of 5 specimens in each group was taken as the tensile strength.

[0079] 2) Tensile strength test after PCT treatment:

[0080] The standard specimens obtained from the examples and comparative examples were placed in a constant temperature and humidity chamber of model EHS-221M manufactured by Espec. After being treated at 121°C and 100% relative humidity for 100 hours, they were taken out and subjected to the tensile strength test described above to evaluate the tensile strength after PCT treatment. The average value of 5 specimens in each group was taken as the tensile strength after PCT treatment.

[0081] 3) Calculation of tensile strength retention after PCT treatment:

[0082] Assuming the tensile strength evaluated by the above test method is S1, and the tensile strength after PCT treatment is S2, the tensile strength retention rate after PCT treatment is calculated according to the following formula (1):

[0083]

[0084] Examples 1-8:

[0085] The raw materials are shown in Table 1. Granulation was performed using a TEX30α twin-shaft extruder (L / D = 45.5) manufactured by Nippon Steel Works. The extruder has 13 heating zones, two feeding devices with metering instruments, and a vacuum exhaust system. Except for glass fiber, all other raw materials were mixed and added through the main feed port of the extruder, while the glass fiber was added through the side feed port. The extruder temperature was set to 200℃-330℃. After melting, extrusion, cooling, and pelletizing, granulated polyphenylene sulfide resin composition was obtained. This granulated material was dried in an oven at 130℃ for 3 hours and then injection molded into ISO standard test strips (test strip mold dimensions: 10mm wide × 4mm thick) using a NEX50 injection molding machine manufactured by Nissei Resin Industries, Ltd., at a molding temperature of 330℃ and a mold temperature of 130℃. Performance tests were then conducted according to the above test methods. The tensile strength is shown in Table 1, and the data on the tensile strength and tensile strength retention rate after 100 hours of PCT treatment are shown in Table 3.

[0086] Comparative Examples 1-8:

[0087] The preparation method is the same as in Example 1. The raw materials and tensile strength are shown in Table 2. The tensile strength and tensile strength retention rate after 100 hours of PCT treatment are shown in Table 3.

[0088] Table 1

[0089]

[0090] Table 2

[0091]

[0092] Table 3

[0093]

[0094] As can be seen from the comparison between Examples 1-8 and Comparative Examples 1-5, the present invention, by mixing (A) poly(p-phenylene sulfide) homopolymer, (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer and (C) inorganic filler in specific amounts, increases the tensile strength, tensile strength after 100 hours of PCT treatment and the strength retention rate of the resin composition, and the resin composition has better mechanical properties and resistance to damp heat.

[0095] As can be seen from the comparison of Comparative Examples 6-8, when no inorganic filler is added, the mechanical strength of the poly(p-phenylene sulfide) homopolymer decreases relative to the poly(p-phenylene sulfide) homopolymer. However, as can be seen from the comparison of Example 1 with Comparative Examples 1 and 2, the resin composition formed by further adding inorganic filler to the mixture of the above-mentioned poly(p-phenylene sulfide) homopolymer and the above-mentioned poly(p-phenylene sulfide)-m-phenylene sulfide copolymer exhibits a particularly high mechanical strength compared to resin compositions using only poly(p-phenylene sulfide) homopolymer and inorganic filler or resin compositions using only poly(p-phenylene sulfide)-m-phenylene sulfide copolymer and inorganic filler.

Claims

1. A polyphenylene sulfide resin composition comprising: (A) Poly(p-phenylene sulfide) homopolymer; (B) Poly(p-phenylene sulfide)-m-phenylene sulfide copolymer; and (C) Inorganic fillers, The (A) poly(p-phenylene sulfide) homopolymer is a linear poly(p-phenylene sulfide). The (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is a random copolymer. The inorganic filler (C) is glass fiber and calcium carbonate. Relative to 100 parts by weight of the (A) poly(p-phenylene sulfide) homopolymer, the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer is 10-200 parts by weight; Relative to 100 parts by weight of the total mass of the (A) poly(p-phenylene sulfide) homopolymer and the (B) poly(p-phenylene sulfide-m-phenylene sulfide) copolymer, the glass fiber comprises 70.7 parts by weight and the calcium carbonate comprises 0.9 parts by weight. in, The m-phenylene sulfide units contained in the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, relative to the total mass of the phenylene sulfide units in the (A) poly(p-phenylene sulfide) homopolymer and the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, constitute 1-13 wt%. In the (B) poly(p-phenylene sulfide)-m-phenylene sulfide copolymer, the m-phenylene sulfide unit has a content of 10-20 wt% relative to the total mass of phenylene sulfide units in the copolymer.

2. The polyphenylene sulfide resin composition according to claim 1, further comprising (D) a silane compound.

3. The polyphenylene sulfide resin composition according to claim 2, wherein, The (D) silane compound is an alkoxysilane compound containing an epoxy group.

4. A molded article, characterized in that: It is obtained using the polyphenylene sulfide resin composition according to any one of claims 1-3.

5. The molded article as described in claim 4, used in a cooling water and antifreeze circulation system.

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