Thermoplastic elastomer resin composition

Abstract

To provide a thermoplastic elastomer resin composition which has strength and flexibility required for a molding, achieves high heat resistance and excellent hydrolysis resistance and is also excellent in moldability, in applications such as automobile, electric machine and industrial applications.SOLUTION: A thermoplastic elastomer resin composition contains a thermoplastic polyester elastomer (A) composed of a polyester block copolymer which contains 40-80 wt.% of a high melting point crystalline polymer segment (a1) composed of a crystalline aromatic polyester unit and 20-60 wt.% of a low melting point polymer segment (a2) composed of an aliphatic polyether unit, and contains 0.05-10 pts.wt. of a novolac type epoxy resin (B1) or a polycarbodiimide compound (B2), 0-5 pts.wt. of a bifunctional epoxy resin (C), 0.1-20 pts.wt. of a glycidyl group-modified polyolefin resin (D), and 0.5-15 pts.wt. of a polyamide resin (E), with respect to 100 pts.wt. of the thermoplastic polyester elastomer (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic elastomer composition that is flexible, has excellent heat resistance and hydrolysis resistance, and also has excellent moldability. [Background technology]

[0002] Polyester block copolymers, which have crystalline aromatic polyester units as high-melting crystalline polymer segments and aliphatic polyether units such as poly(alkylene oxide) glycol and / or aliphatic polyester units such as polylactone as low-melting polymer segments, are widely used in automotive parts and industrial materials because they have excellent mechanical properties such as strength, impact resistance, elastic recovery, flexibility, and flexural fatigue resistance, as well as low- and high-temperature properties, and are also thermoplastic and easy to mold.

[0003] However, although the hydrolysis resistance of the polyester block copolymer generally improves as the proportion of the low-melting point crystalline polymer segment increases, at high temperatures the heat resistance decreases as the proportion of the low-melting point crystalline polymer segment increases. Therefore, it has been difficult to provide a material that has excellent flexibility and that combines hydrolysis resistance and heat resistance.

[0004] As a method for improving heat resistance, for example, a block polyetherester copolymer composition in which a polyamide resin and a hindered phenol-based antioxidant, a sulfur-based antioxidant, and / or a phosphorus-based antioxidant are added to a polyetherester block copolymer (see, for example, Patent Document 1), and a polyester elastomer resin composition in which an aromatic amine-based antioxidant, a hindered phenol-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, and / or a polyamide resin are added to a polyester elastomer (see, for example, Patent Document 2) have been proposed.

[0005] Also proposed are a block polyetherester copolymer composition in which a glycidyl group-modified polyolefin resin and a polyamide resin are added to a mixture of a polyetherester block copolymer having two types of dicarboxylic acid components and a rigid polyester resin (see, for example, Patent Document 3), and a block polyetherester copolymer composition in which a glycidyl group-modified polyolefin resin and a polyamide resin are added to a mixture of a polyetherester block copolymer having two types of dicarboxylic acid components and a polyetherester block copolymer in which the dicarboxylic acid component is terephthalic acid or an ester-forming derivative thereof (see, for example, Patent Document 4).

[0006] Furthermore, polyether ester block copolymers are prone to degradation due to hydrolysis, and methods for improving this include using a carbodiimide in combination with a bifunctional or higher functional epoxy compound (see, for example, Patent Document 5), blending a novolac epoxy resin with a thermoplastic polyester resin (see, for example, Patent Documents 6 and 7), and using a carbodiimide compound in combination with an epoxy compound and blending a polyamide compound (see, for example, Patent Document 8). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2-173059 [Patent Document 2] Japanese Patent Application Publication No. 11-323109 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-189550 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-177566 [Patent Document 5] International Publication No. 2007 / 029768 [Patent Document 6] International Publication No. 2015 / 072216 [Patent Document 7] International Publication No. 2017 / 001776 [Patent Document 8] International Publication No. 2017 / 138548 Summary of the Invention [Problem to be solved by the invention]

[0008] However, with the compositions of Patent Documents 1 and 2, as long as they are basically polyether ester block copolymers, it is difficult to achieve a high level of heat resistance, even if the heat resistance can be improved to a certain extent.

[0009] Furthermore, although the compositions of Patent Documents 3 and 4 provide a high level of heat resistance, there is a problem in that they have reduced hydrolysis resistance.

[0010] Furthermore, the methods of Patent Documents 5, 6, 7 and 8 improve hydrolysis resistance, but have the problem of not being able to obtain sufficient heat resistance.

[0011] The present invention was achieved as a result of investigations aimed at solving the problems of the prior art described above, and an object of the present invention is to provide a thermoplastic elastomer resin composition which has the strength and flexibility required for molded articles, high heat resistance and hydrolysis resistance, and excellent moldability. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the present invention employs the following means: That is, the present invention comprises a thermoplastic polyester elastomer (A) comprising a polyester block copolymer having as its constituent components 40 to 80% by weight of a high-melting-point crystalline polymer segment (a1) comprising a crystalline aromatic polyester unit and 20 to 60% by weight of a low-melting-point polymer segment (a2) comprising an aliphatic polyether unit, and the thermoplastic polyester elastomer (A) comprises: The thermoplastic elastomer resin composition is characterized by containing 0.05 to 10 parts by weight of a novolac epoxy resin (B1) or a polycarbodiimide compound (B2), 0 to 5 parts by weight of a bifunctional epoxy resin (C), 0.1 to 20 parts by weight of a glycidyl group-modified polyolefin resin (D), and 0.5 to 15 parts by weight of a polyamide resin (E). [Effects of the Invention]

[0013] According to the present invention, as will be described below, it is possible to obtain a thermoplastic elastomer resin composition that has the strength and flexibility required for molded articles, high heat resistance, excellent hydrolysis resistance, and excellent moldability. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will now be described.

[0015] The thermoplastic polyester elastomer (A) used in the present invention is a polyester block copolymer comprising, as its constituent components, a high-melting crystalline polymer segment (a1) mainly composed of crystalline aromatic polyester units and a low-melting polymer segment (a2) mainly composed of aliphatic polyether units, and the high-melting crystalline polymer segment is mainly composed of crystalline aromatic polyester units, i.e., it is a polyester formed mainly from an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative.

[0016] Examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracene dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethane dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, and sodium 3-sulfoisophthalate. In the present invention, the aromatic dicarboxylic acid is primarily used, but a portion of the aromatic dicarboxylic acid may be substituted with an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, or 4,4'-dicyclohexyldicarboxylic acid, or an aliphatic dicarboxylic acid such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, or dimer acid. Furthermore, ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters, aryl esters, carbonate esters, and acid halides, may also be used.

[0017] The aromatic dicarboxylic acid or its ester-forming derivative as the dicarboxylic acid component is preferably terephthalic acid or dimethyl terephthalate, more preferably terephthalic acid.

[0018] The diol or its ester-forming derivative is preferably a diol having a molecular weight of 400 or less, for example, an aliphatic diol such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, or decamethylene glycol; an alicyclic diol such as 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, or tricyclodecanedimethanol; or an aromatic diol such as xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxy)diphenylpropane, 2,2′-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxyethoxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4′-dihydroxy-p-terphenyl, or 4,4′-dihydroxy-p-quarterphenyl. Such diols may also be used in the form of an ester-forming derivative, for example, an acetylated form or an alkali metal salt.

[0019] Two or more of these dicarboxylic acids, derivatives thereof, diol components and derivatives thereof may be used in combination.

[0020] Preferred examples of such high melting point crystalline polymer segment (a1) include those comprising polybutylene terephthalate units derived from terephthalic acid or dimethyl terephthalate and 1,4-butanediol, and polybutylene isophthalate units derived from isophthalic acid or dimethyl isophthalate and 1,4-butanediol.

[0021] The copolymerization amount of the high melting point crystalline polymer segment (a1) is 40 to 80% by weight, and preferably 50 to 70% by weight.

[0022] The copolymerization amount of the high melting point crystalline polymer segment (a1) is, for example, the sum of the mass % of terephthalic acid and 1,4-butanediol when the constituent component of the high melting point crystalline polymer segment (a1) is polybutylene terephthalate unit.

[0023] The low melting point polymer segment (a2) used in the thermoplastic polyester elastomer (A) used in the present invention is mainly composed of an aliphatic polyether.

[0024] Specific examples of such aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(trimethylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide adduct of poly(propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran, etc. Among these, poly(tetramethylene oxide) glycol and / or an ethylene oxide adduct of poly(propylene oxide) glycol and / or a copolymer of ethylene oxide and tetrahydrofuran are preferably used.

[0025] The copolymerization amount of the low melting point polymer segment (a2) in the thermoplastic polyester elastomer (A) used in the present invention is 20 to 60% by weight, and preferably 30 to 50% by weight.

[0026] For example, when the constituent component of the low melting point crystalline polymer segment (a2) is a poly(tetramethylene oxide) glycol unit, the copolymerization amount of the low melting point crystalline polymer segment (a2) is expressed as mass % of poly(tetramethylene oxide) glycol.

[0027] The thermoplastic polyester elastomer (A) used in the present invention can be produced by any known method, such as a method of transesterifying a lower alcohol diester of a dicarboxylic acid, an excess amount of a low-molecular-weight glycol, and a low-melting polymer segment component in the presence of a catalyst, followed by melt polycondensation of the resulting reaction product, or a method of esterifying a dicarboxylic acid, an excess amount of a glycol, and a low-melting polymer segment component in the presence of a catalyst, followed by melt polycondensation of the resulting reaction product.

[0028] The thermoplastic polyester elastomer (A) obtained by polycondensation may then be subjected to solid-state polycondensation. Solid-state polycondensation is carried out at a temperature at which the thermoplastic polyester elastomer (A) pelletized after melt polycondensation does not fuse, and is usually carried out in the temperature range of 140°C to 220°C. It is desirable to carry out preliminary crystallization and drying steps before the solid-state polycondensation. Furthermore, solid-state polycondensation is carried out under high vacuum or in an inert gas flow. In the case of a high vacuum, the process is carried out under reduced pressure, preferably 665 Pa or less, more preferably 133 Pa or less. In the case of an inert gas flow, the process is typically carried out under a nitrogen gas flow. The pressure is not particularly limited, but atmospheric pressure is preferred. A rotatable vacuum dryer or a tower dryer capable of flowing an inert gas is preferably used as the reaction vessel.

[0029] Examples of the novolac epoxy resin (B1) used in the present invention include phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol novolac epoxy resin, naphthol novolac epoxy resin, naphthol-phenol co-condensed novolac epoxy resin, naphthol-cresol co-condensed novolac epoxy resin, etc. Two or more of these may be blended.

[0030] The polycarbodiimide compound (B2) used in the present invention can be selected from compounds obtained by polymerizing aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, and mixtures thereof. Specific examples of polycarbodiimides include poly(1,6-hexamethylenecarbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-dicyclohexylmethanecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), Examples of suitable polycarbodiimides include poly(m-phenylenecarbodiimide), poly(tolylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(1,3,5-triisopropylbenzene)polycarbodiimide, poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene)polycarbodiimide, poly(triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide). Among these, aromatic polycarbodiimide compounds are preferred from the viewpoint of heat resistance.

[0031] The amount of the novolac epoxy resin (B1) or polycarbodiimide compound (B2) to be blended is 0.05 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer composition (A). If the amount is less than 0.05 parts by weight, sufficient effect cannot be obtained, while if the amount exceeds 10 parts by weight, the viscosity increases significantly, resulting in poor moldability.

[0032] The bifunctional epoxy resin (C) used in the present invention is a compound containing two epoxy groups per molecule, and may be in liquid or solid form. Examples include glycidyl ether-based epoxy compounds, which are polycondensates of epichlorohydrin with phenolic compounds such as bisphenol A, resorcinol, hydroquinone, pyrocatechol, bisphenol F, saligenin, bisphenol S, 4,4'-dihydroxybiphenyl, 1,5-dihydroxynaphthalene, and cashew phenol; glycidyl ester-based epoxy compounds such as glycidyl phthalate; and glycidyl amine-based epoxy compounds such as N,N'-methylenebis(N-glycidylaniline). Two or more of these may also be blended.

[0033] Among these, glycidyl ether epoxy compounds are preferred because they can suppress decomposition during melt processing, and bisphenol A epoxy compounds are preferred because they can improve the surface free energy of the resin composition and prevent penetration by chemicals such as industrial lubricants and greases, thereby improving chemical resistance, which is resistance to deterioration caused by contact with high-temperature chemicals. Component (C) used in the present invention does not include novolac epoxy compounds.

[0034] Furthermore, among bisphenol A type epoxy compounds, bisphenol A type epoxy resins with an epoxy value of 300 to 3000 g / eq are preferred. When the epoxy value of the bisphenol A type epoxy resin is 300 g / eq or more, the amount of gas generated during melt processing can be suppressed. An epoxy value of 500 g / eq or more is more preferred. Furthermore, when the epoxy value of the bisphenol A type epoxy resin is 3000 g / eq or less, both long-term hydrolysis resistance and high-temperature melt retention stability can be achieved at higher levels. An epoxy value of 2000 g / eq or less is even more preferred.

[0035] The amount of the bifunctional epoxy resin (C) to be blended is 0 to 5 parts by weight based on 100 parts by weight of the thermoplastic polyester elastomer composition (A).

[0036] These novolac type epoxy resin (B1), polycarbodiimide compound (B2), and bifunctional epoxy resin (C) can prevent the polymer from hydrolysis by blocking the carboxyl terminal groups of the polymer.

[0037] The glycidyl group-modified polyolefin resin (D) used in the present invention is preferably a copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated carboxylic acid, or a terpolymer consisting of an α-olefin, an α,β-unsaturated carboxylic acid alkyl ester, and a glycidyl ester of an α,β-unsaturated carboxylic acid, and is particularly preferably a terpolymer consisting of an α-olefin, an α,β-unsaturated carboxylic acid alkyl ester, and a glycidyl ester of an α,β-unsaturated carboxylic acid. Examples of α-olefins include ethylene, propylene, and butene-1, with ethylene being the most preferred.

[0038] Examples of glycidyl esters of α,β-unsaturated carboxylic acids include glycidyl acrylate, glycidyl methacrylate, and glycidyl ethacrylate, with glycidyl methacrylate being preferred. Examples of α,β-unsaturated carboxylic acid alkyl esters include esters of acrylic acid or methacrylic acid with monohydric alcohols having 1 to 8 carbon atoms, with methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate being preferred, with methyl acrylate, ethyl acrylate, and butyl acrylate being particularly preferred.

[0039] The amount of the glycidyl group-modified polyolefin resin (D) to be blended is 0.1 to 20 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer composition (A). If the amount is less than 0.1 part by weight, the degree of improvement in the intended effect is small, while if the amount exceeds 20 parts by weight, gelation occurs due to molten retention during molding, and moldability deteriorates.

[0040] The polyamide resin (E) used in the present invention is a polymeric compound having an amide bond in the molecular chain, and examples thereof include polymers from lactams, polymers of salts obtained by reacting adipic acid, sebacic acid, dodecanedioic acid, etc. with ethylenediamine, hexamethylenediamine, metaxylenediamine, etc., and polymers from ω-aminocarboxylic acids. These polyamide resins may be copolymers, or two or more different polymers may be used in combination. Among these polyamide resins, even greater effects can be obtained when nylon 6 and / or di- or ternary or higher copolymer polyamide resins are used.

[0041] The amount of polyamide resin (E) is 0.5 to 15 parts by weight, preferably 1 to 15 parts by weight, and more preferably 1.5 to 15 parts by weight, per 100 parts by weight of thermoplastic polyester elastomer composition (A). If the amount of polyamide resin (E) is less than 0.5 parts by weight, the degree of the desired improving effect is small, while if it exceeds 15 parts by weight, the flexibility and rubber-like properties inherent to the polyether ester block copolymer are impaired, which is undesirable.

[0042] The thermoplastic elastomer composition of the present invention can have improved heat resistance by further adding an antioxidant (F).

[0043] The antioxidant (F) used in the present invention may be one or more selected from the group consisting of aromatic amine antioxidants, hindered phenol antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

[0044] Specific examples of aromatic amine antioxidants include phenylnaphthylamine, 4,4'-dimethoxydiphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, and 4-isopropoxydiphenylamine, and among these, the use of diphenylamine compounds is preferred.

[0045] Specific examples of hindered phenol antioxidants include 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, hydroxymethyl-2,6-di-t-butylphenol, 2,6-di-t-α-dimethylamino-p-cresol, 2,5-di-t-butyl-4-ethylphenol, 4,4'-bis(2,6-di-t-butylphenol), 2,2'-methylene-bis-4-methyl-6-t-butylphenol, and 2,2'-methylene-bis(4-ethyl-6-t-butylphenol). ), 4,4'-methylene-bis(6-t-butyl-o-cresol), 4,4'-methylene-bis(2,6-di-t-butylphenol), 2,2'-methylene-bis(4-methyl-6-cyclohexylphenol), 4,4'-butylidene-bis(3-methyl-6-t-butylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), bis(3-methyl-4-hydroxy-5-t-butylbenzyl) sulfide, 4,4'-thiobis(6-t-butyl-o-cresol), 2,2'-thiobis(4-methyl-6-t-butylphenol) Alcohol), 2,6-bis(2'-hydroxy-3'-t-butyl-5'-methylbenzyl)-4-methylphenol, diethyl ester of 3,5-di-t-butyl-4-hydroxybenzenesulfonic acid, 2,2'-dihydroxy-3,3'-di(α-methylcyclohexyl)-5,5'-dimethyl-diphenylmethane, α-octadecyl-3(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 6-(hydroxy-3,5-di-t-butylanilino)-2,4-bis-octyl-thio-1,3,5-triazine, hexamethyl glycol-bis[β-(3,5-di-t-butyl-4-hydroxyphenol)propionate], N,N'-hexamethylene-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamic acid amide), 2,2-thio[diethyl-bis-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate], dioctadecyl ester of 3,5-di-t-butyl-4-hydroxybenzenephosphonic acid, tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 1,3,5-trimethyl-2,4,Examples include 6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,1,3-tris(2-methyl-4-hydroxy-5-di-t-butylphenyl)butane, tris(3,5-di-t-butyl-4-hydroxyphenyl)isocyanurate, and tris[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl-oxyethyl]isocyanurate. Among these, those with a molecular weight of 500 or more, such as tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, are particularly preferred.

[0046] The sulfur-based antioxidants are compounds containing sulfur, such as thioethers, dithioacid salts, mercaptobenzimidazoles, thiocarbanilides, and thiodipropionates. Among these, thiodipropionates are particularly preferred.

[0047] Phosphorus-based antioxidants are compounds containing phosphorus, such as phosphoric acid, phosphorous acid, hypophosphorous acid derivatives, phenylphosphonic acid, polyphosphonates, dialkyl pentaerythritol diphosphites, and dialkyl bisphenol A diphosphites. Among these, it is preferable to use compounds having both phosphorus and sulfur atoms in the molecule, or compounds having two or more phosphorus atoms in the molecule.

[0048] The total amount of these antioxidants (F) added is 0.01 to 5 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.10 to 5 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer composition (A).

[0049] By setting the total amount of antioxidants to 0.01 parts by weight or more, the degree to which the desired improving effect can be obtained increases, and by setting the amount to 5 parts by weight or less, blooming is less likely to occur and the mechanical strength of the polyester block copolymer is less likely to decrease, which is preferable.

[0050] Furthermore, in addition to the additives (B1), (B2), and (C) to (F), various additives may be added to the thermoplastic elastomer resin composition of the present invention, provided that the object of the present invention is not impaired. For example, known molding aids such as crystal nucleating agents and lubricants, light resistance additives such as ultraviolet absorbers and hindered amine compounds, hydrolysis resistance improvers, colorants such as pigments and dyes, antistatic agents, conductive agents, flame retardants, reinforcing agents, fillers, plasticizers, and mold release agents may be optionally added.

[0051] The method for producing the thermoplastic elastomer resin composition of the present invention is not particularly limited, and examples thereof include a method in which a raw material obtained by blending a polyester block copolymer with a novolac epoxy resin (B1) or a polycarbodiimide compound (B2), a bifunctional epoxy resin (C), a glycidyl group-modified polyolefin resin (D), a polyamide resin (E), and an antioxidant (F) is fed into a screw extruder and melt-kneaded; or a method in which a screw extruder is first fed with a polyester block copolymer, a novolac epoxy resin (B1) or a polycarbodiimide compound (B2), and a bifunctional epoxy resin (C) and melted, then fed with a glycidyl group-modified polyolefin resin (D) through another feed port and kneaded, and finally fed with a polyamide resin (E), an antioxidant (F), and other ingredients through another feed port and kneaded.

[0052] The thermoplastic elastomer resin composition of the present invention can be molded into a molded article by injection molding, blow molding, extrusion molding, compression molding or the like. [Example]

[0053] The effects of the present invention will be explained below with reference to examples. The present invention can be practiced with appropriate modifications within the scope of the gist of the invention. In the examples, % and parts are all by weight unless otherwise specified. In addition, the physical properties shown in the examples were measured by the following measuring methods.

[0054] Melt Flow Rate (MFR) Measurement was carried out in accordance with ASTM D1238 at 240°C and a load of 2160 g.

[0055] [Tensile strength at break, tensile elongation at break] The pellets were dried with hot air at 90°C for more than 3 hours and then molded into JIS K7113 No. 2 dumbbell test pieces using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industrial Co., Ltd.) under molding conditions of a cylinder temperature of 240°C and a mold temperature of 50°C. Measurements were then performed in accordance with JIS K7113 (1995 edition).

[0056] [Heat aging] Pellets were dried with hot air at 90°C for more than 3 hours and then molded using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industrial Co., Ltd.) under molding conditions of specified cylinder temperature and mold temperature. JIS K 7113 Type 2 test specimens were then left in a hot air oven at 160°C for 400 hours, removed, and measured according to JIS K 7113 (1995 edition). The tensile elongation at break was evaluated using the following three levels. ◎: Tensile elongation at break is 80% or more. ◯: The tensile elongation at break is 40% or more and less than 80%. ×: The tensile elongation at break is less than 40%.

[0057] [Hydrolysis resistance] Pellets were dried with hot air at 90°C for more than 3 hours and then molded using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industrial Co., Ltd.) under molding conditions of specified cylinder temperature and mold temperature. JIS K 7113 Type 2 test pieces were then left in a constant temperature and humidity chamber at 80°C and 95% RH for 2500 hours, then removed and measured according to JIS K 7113 (1995 edition). The tensile elongation at break was evaluated using the following three levels. ◎: Tensile elongation at break is 200% or more. ◯: The tensile elongation at break is 100% or more and less than 200%. ×: The tensile elongation at break is less than 100%.

[0058] [Production of Polyester Elastomer (A-1)] 505 parts of terephthalic acid and 251 parts of 1,4-butanediol were used as the high-melting crystalline polymer segment (a1), and 354 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of approximately 1400 as the low-melting polymer segment (a2) were added to a reaction vessel equipped with a helical ribbon stirrer, along with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide. The mixture was heated to 190-225 °C for 3 hours to carry out an esterification reaction while distilling the reaction water out of the system. 2.0 parts of titanium tetrabutoxide were added to the reaction mixture, and 0.5 parts of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy) were added. The mixture was then heated to 245 °C, and the pressure in the system was reduced to 0.2 mmHg over 50 minutes. Melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The resulting polyester elastomer was discharged in the form of a strand into water and cut into pellets.

[0059] The weight percentage of the high melting point crystalline polymer segment (a1) was 65, and the weight percentage of the low melting point polymer segment (a2) was 35.

[0060] [Production of Polyester Elastomer (A-2)] 420 parts of terephthalic acid and 196 parts of 1,4-butanediol were used as the high-melting crystalline polymer segment (a1), and 480 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of approximately 1400 were used as the low-melting polymer segment (a2). Together with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide, the mixture was charged into a reaction vessel equipped with a helical ribbon stirrer and heated at 190-225 °C for 3 hours to carry out an esterification reaction while distilling the reaction water out of the system. After adding 2.0 parts of titanium tetrabutoxide and 0.5 parts of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy), the mixture was heated to 245 °C, and the pressure in the system was reduced to 0.2 mmHg over 50 minutes. Melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The resulting polyester elastomer was discharged in the form of a strand into water and cut into pellets.

[0061] The weight percentage of the high melting point crystalline polymer segment (a1) was 52, and the weight percentage of the low melting point polymer segment (a2) was 48.

[0062] [Production of Polyester Elastomer (A-3)] 593 parts of terephthalic acid and 307 parts of 1,4-butanediol were used as the high-melting crystalline polymer segment (a1), and 229 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of approximately 1400 as the low-melting polymer segment (a2) were added to a reaction vessel equipped with a helical ribbon stirrer, along with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide. The mixture was heated to 190-225 °C for 3 hours to carry out an esterification reaction while distilling the reaction water out of the system. 2.0 parts of titanium tetrabutoxide were added to the reaction mixture, and 0.5 parts of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy Corporation) were added. The mixture was then heated to 245 °C, and the pressure in the system was reduced to 0.2 mmHg over 50 minutes. Melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The resulting polyester elastomer (A-3) was extruded into water in the form of a strand and cut into pellets. The weight percentage of the high melting point crystalline polymer segment (a1) was 78%, and the weight percentage of the low melting point polymer segment (a2) was 22%.

[0063] [Novolac-type epoxy resin (B1)] As the novolac type epoxy resin (B1), NC-3000 manufactured by Nippon Kayaku Co., Ltd. was used.

[0064] [Polycarbodiimide compound (B2)] Stavaxol P manufactured by Lanxess was used as the polycarbodiimide compound.

[0065] [Difunctional epoxy resin (C)] As the bifunctional epoxy resin (C), jER1007 manufactured by Mitsubishi Chemical Corporation was used.

[0066] [Glycidyl-modified polyolefin resin (D)] As the glycidyl group-modified polyolefin resin (D), Bondfast 7M (a terpolymer of ethylene, methyl acrylate, and glycidyl methacrylate) manufactured by Sumitomo Chemical Co., Ltd. was used.

[0067] [Polyamide resin (E)] As the polyamide resin (E), Amilan CM4000 (a ternary copolymer of polycaprolactam, polyhexamethylene adipamide, and polyhexamethylene sebacamide) manufactured by Toray Industries, Inc. was used.

[0068] [Antioxidant (F)] Table 1 shows the abbreviations and structural formulae of antioxidants F-1 (aromatic amine type), F-2 (hindered phenol type), and F-3 (sulfur type) used in the following examples.

[0069] [Table 1]

[0070] [Examples 1 to 4] Using a twin-screw extruder with a 45 mm screw, the polyester elastomers (A-1), (A-2), and (A-3) shown in the Reference Examples, the novolac epoxy resin (B1) or polycarbodiimide compound (B2), the glycidyl-modified polyolefin resin (D), the polyamide resin (E), the antioxidant (F), and optionally the bifunctional epoxy resin (C) were mixed according to the formulations shown in Table 2 and added from the main charge. Melt mixing was carried out under extrusion conditions of a heating temperature of 250°C and a screw rotation of 150 rpm, and the mixture was extruded in the form of a strand, passed through a cooling bath, and pelletized with a strand cutter to obtain a thermoplastic polyester elastomer resin composition.

[0071] The resulting pellets were dried at 90°C for 3 hours and then injection molded at a cylinder temperature of 230-250°C and a mold temperature of 50°C to obtain test specimens for tensile strength at break, tensile elongation at break, heat aging resistance, and hydrolysis resistance tests. Various tests were performed using the resulting test specimens. Tensile strength at break and tensile elongation at break were measured at 23°C. Heat aging resistance was evaluated by treating the specimens for 400 hours in an oven at 160°C and then conducting tensile tests (tensile strength at break and tensile elongation at break) at 23°C. Hydrolysis resistance was evaluated by treating the specimens for 2500 hours in a thermo-hygrostat at 80°C and 95% RH and then conducting tensile tests (tensile strength at break and tensile elongation at break) at 23°C. The test results are shown in Table 2.

[0072] [Table 2]

[0073] As is clear from the results in Table 2, the thermoplastic elastomer resin compositions of the present invention, which are prepared by blending the polyester elastomer (A) shown in Examples 1 to 5 with a novolac epoxy resin (B1) or a polycarbodiimide compound (B2), a glycidyl-modified polyolefin resin (D), a polyamide resin (E), and an antioxidant (one or more of an aromatic amine antioxidant, a hindered phenol antioxidant, and a sulfur-based antioxidant), and optionally a bifunctional epoxy resin (C), exhibit excellent tensile strength at break and tensile elongation at break. They also exhibit excellent heat aging resistance and hydrolysis resistance. On the other hand, the resin compositions of Comparative Examples 1 to 4, which do not satisfy the requirements of the present invention, are inferior to the resin compositions of the present invention in any of tensile strength at break, tensile elongation at break, heat aging resistance, and hydrolysis resistance. [Industrial Applicability]

[0074] As described above, the thermoplastic elastomer resin composition of the present invention has sufficient strength and rigidity for use in molded articles, and also has excellent heat aging resistance and hydrolysis resistance, making it suitable for use in products that require flexibility, heat resistance, and easy hydrolysis resistance, such as automotive parts, electrical equipment, and industrial goods.

Claims

1. A thermoplastic elastomer resin composition comprising a thermoplastic polyester elastomer (A) comprising a polyester block copolymer having as its constituent components 40 to 80% by weight of a high-melting-point crystalline polymer segment (a1) comprising a crystalline aromatic polyester unit and 20 to 60% by weight of a low-melting-point polymer segment (a2) comprising an aliphatic polyether unit, and further comprising, per 100 parts by weight of the thermoplastic polyester elastomer (A), 0.05 to 10 parts by weight of a novolac epoxy resin (B1) or an aromatic polycarbodiimide compound (B2), 0 to 5 parts by weight of a bifunctional epoxy resin (C), 0.1 to 20 parts by weight of a glycidyl-modified polyolefin resin (D), and 0.5 to 15 parts by weight of a polyamide resin (E).

2. 2. The thermoplastic elastomer resin composition according to claim 1, further comprising 0.01 to 5 parts by weight of an antioxidant (F) per 100 parts by weight of the thermoplastic polyester elastomer (A).

3. 3. The thermoplastic elastomer resin composition according to claim 1, wherein the bifunctional epoxy resin (C) is a bisphenol A type epoxy resin.

4. The thermoplastic elastomer resin composition according to any one of claims 1 to 3, wherein the glycidyl group-modified polyolefin resin (D) is a copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated carboxylic acid, or a terpolymer of an α-olefin, an α,β-unsaturated carboxylic acid alkyl ester, and a glycidyl ester of an α,β-unsaturated carboxylic acid.

5. The thermoplastic elastomer resin composition according to any one of claims 1 to 4, wherein the polyamide resin (E) comprises nylon 6 and / or a di- or ternary or more copolymer polyamide resin.

6. 3. The thermoplastic elastomer according to claim 2, wherein the antioxidant (F) is one or more selected from the group consisting of aromatic amine-based antioxidants, hindered phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. mer resin composition.

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