Polyester elastomer resin composition and molded article

Abstract

To provide a polyester elastomer resin composition which not only exhibits excellent transparency but also suppresses discoloration due to heat, and is excellent in appearance.SOLUTION: A polyester elastomer resin composition contains, with respect to 100 pts.mass of a polyester block copolymer (A) containing 10 to 50 mass% of a high melting point crystalline polymer segment (a) composed of a crystalline aromatic polyester unit and 90 to 50 mass% of a low melting point polymer segment (b) composed of an aliphatic polyether unit and / or an aliphatic polyester unit as main components, 0.2 to 20 pts.mass of an ethylene copolymer (C) having a carboxylic acid metal base at the side chain, and 0.05 pts.mass or more and less than 0.30 pts.mass of a hindered phenolic radical scavenger (D) composed of carbon and oxygen, contains 0.05 to 1.0 pts.mass of a peroxide decomposer (E), has a haze value measured with a sheet having a thickness of 2 mm of 85% or less, and a color difference ΔE when the sheet having the thickness of 2 mm is heat treated at 140°C for 24 hours of 0.1 to 5.0.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyester elastomer resin composition.

Background Art

[0002] Polyester elastomers having crystalline aromatic polyester units such as polybutylene terephthalate units as hard segments and aliphatic polyether units such as poly(alkylene oxide) glycols as soft segments are excellent not only in extrusion moldability and injection moldability, but also have high mechanical strength, rubber-like properties such as impact resistance, elastic recovery, flex fatigue resistance, flexibility, low-temperature and high-temperature characteristics, water resistance, chemical resistance, etc., and are further thermoplastic and easy to mold, so they are expanding their applications in the fields of automotive parts, electrical and electronic parts, fibers, films, etc.

[0003] Although it is such a useful polyester elastomer, it becomes cloudy and opaque when cooled and solidified even though it is transparent when melted.

[0004] As a method of imparting transparency to a polyester elastomer, a method of blending an aliphatic carboxylic acid alkali metal salt with a polyether polyester block copolymer is known (for example, Patent Documents 1, 2, etc.). However, in a system blended with an aliphatic carboxylic acid sodium salt, an excessive amount of addition is required to generate sufficient transparency. As a result, there are also many problems such as yellowing due to the decomposition of the main chain of the polyester by the aliphatic carboxylic acid sodium salt, discoloration due to light and heat, and poor appearance of the molded product due to the bleed-out of the aliphatic carboxylic acid sodium salt.

[0005] Furthermore, a method has been proposed in which an ionomer resin, such as an alkali metal salt of an ethylene-methacrylic acid copolymer, is blended with a polyester elastomer (for example, Patent Document 3). In this method, because the molecular weight of the ionomer resin is large and it has good compatibility with polyester, it is possible to obtain a resin composition with little bleed-out and relatively transparency. However, this method requires the addition of an excess amount of ionomer resin, and as a result, there are many problems such as discoloration due to light and heat, a decrease in mechanical strength, and a decrease in transparency due to the excess amount of ionomer resin.

[0006] A method is also known in which an ionomer resin such as an alkali metal salt of an aliphatic carboxylic acid and an alkali metal salt of an ethylene-methacrylic acid copolymer is blended with a polyester elastomer (for example, Patent Document 4). In this method, discoloration due to heat is suppressed by blending a small amount of an alkali metal salt of an aliphatic carboxylic acid and an alkali metal salt of an ethylene-methacrylic acid copolymer, and further by including an antioxidant consisting of a hindered phenol-based antioxidant and a peroxide decomposer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 59-5142 [Patent Document 2] Japanese Patent Application Publication No. 6-306263 [Patent Document 3] Special Publication No. 58-24459 [Patent Document 4] Japanese Patent Application Publication No. 10-182954 [Overview of the project] [Problems that the invention aims to solve]

[0008] While Patent Document 4 can suppress discoloration due to heat to some extent, it has many problems, such as insufficient suppression of discoloration due to heat, making it difficult to apply to materials that require high heat resistance and excellent appearance (color tone).

[0009] The object of the present invention is to provide a polyester elastomer resin composition that maintains excellent transparency, suppresses discoloration due to heat, and has a superior appearance. [Means for solving the problem]

[0010] The inventors focused on the structure of the functional groups of compounds contained in polyester elastomer resin compositions. Specifically, they focused on the structure and content of antioxidants. They found that antioxidants can suppress discoloration due to heat, but if the antioxidant contains a primary or secondary amine structure, it itself causes discoloration due to heat. They also found that the content of the antioxidant is important, and that a specific content can suppress discoloration due to heat while maintaining transparency and color tone.

[0011] As a result of diligent research to achieve the above objective, the inventors have come to propose the following invention. That is, the aspect of the present invention is as follows. (1) A polyester elastomer resin composition characterized by comprising 100 parts by mass of polyester block copolymer (A) mainly composed of 10 to 50% by mass of a high-melting-point crystalline polymer segment (a) consisting of crystalline aromatic polyester units and 90 to 50% by mass of a low-melting-point polymer segment (b) consisting of aliphatic polyether units and / or aliphatic polyester units, 0.2 to 20 parts by mass of ethylene copolymer (C) having a carboxylic acid metal base in the side chain, and 0.05 to less than 0.30 parts by mass of a hindered phenol-based radical scavenger (D) consisting of carbon and oxygen, and 0.05 to 1.0 parts by mass of a peroxide decomposing agent (E), having a haze value of 85% or less measured on a 2 mm thick sheet, and a color difference ΔE of 0.1 to 5.0 when a 2 mm thick sheet is heat-treated at 140°C for 24 hours. (2) The polyester elastomer resin composition according to (1), characterized in that it contains 0.1 to 5 parts by mass of an ultraviolet absorber (F) and 0.1 to 5 parts by mass of a hindered amine compound (G) in which the amine is a tertiary amine, per 100 parts by mass of the polyester block copolymer (A). (3) The polyester elastomer resin composition according to (2), wherein the ultraviolet absorber (F) is one or more selected from the group consisting of benzotriazole compounds, triazine compounds, and cyanoacrylate compounds. (4) A polyester elastomer resin composition according to any one of (1) to (3), comprising 0.01 to 3 parts by mass of an alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (B) per 100 parts by mass of the polyester block copolymer (A). (5) A molded article comprising a polyester elastomer resin composition as described in any of (1) to (4). [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a polyester elastomer resin composition that maintains excellent transparency, suppresses discoloration due to heat, and has a superior appearance. [Modes for carrying out the invention]

[0013] The present invention will be described in detail below.

[0014] The polyester block copolymer (A) used in the present invention mainly comprises a high-melting-point crystalline polymer segment (a) consisting of crystalline aromatic polyester units and a low-melting-point polymer segment (b) consisting of aliphatic polyether units and / or aliphatic polyester units.

[0015] The high-melting-point crystalline polymer segment (a) of the polyester block copolymer (A) used in the present invention is a polyester formed from an aromatic dicarboxylic acid or its ester-forming derivative and an aliphatic diol, preferably polybutylene terephthalate derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol. In addition, dicarboxylic acid components such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or ester-forming derivatives thereof, and diols with a molecular weight of 300 or less, such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol. Polyesters derived from aliphatic diols such as ethylene glycol, neopentyl glycol, and decamethylene glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethylol; xylylene glycol; bis(p-hydroxy)diphenyl; bis(p-hydroxyphenyl)propane; 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane; bis[4-(2-hydroxy)phenyl]sulfone; 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane; aromatic diols such as 4,4'-dihydroxy-p-terphenyl and 4,4'-dihydroxy-p-quarterphenyl; or copolymerized polyesters using two or more of these dicarboxylic acid and diol components in combination. It is also possible to copolymerize polyfunctional carboxylic acid components with three or more functions, polyfunctional oxyacid components, and polyfunctional hydroxyl components in a range of 5 mol% or less.

[0016] The low melting point polymer segment (b) of the polyester block copolymer (A) used in the present invention is an aliphatic polyether and / or an aliphatic polyester. Examples of the aliphatic polyether include poly(ethylene oxide) glycol, poly(propylene 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, a copolymer of ethylene oxide and tetrahydrofuran, and the like.

[0017] Examples of the aliphatic polyester include poly(ε-caprolactone), poly(enantholactone), polycaprylolactone, polybutylene adipate, polyethylene adipate, and the like. Among these aliphatic polyethers and / or aliphatic polyesters, poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, poly(ε-caprolactone), polybutylene adipate, polyethylene adipate, and the like are preferable in view of the elastic properties of the polyester block copolymer obtained. The number average molecular weight of these low melting point polymer segments is preferably about 300 to 6000 in the copolymerized state.

[0018] In the polyester block copolymer (A) used in the present invention, the copolymerization amount of the high melting point crystalline polymer segment (a) is 10 to 50% by mass, and the copolymerization amount of the low melting point polymer segment (b) is 90 to 50% by mass. Preferably, the copolymerization amount of the high melting point crystalline polymer segment (a) in the polyester block copolymer (A) is 10 to 40% by mass, and the copolymerization amount of the low melting point polymer segment (b) is 90 to 60% by mass. When the copolymerization amount of the high melting point crystalline polymer segment (a) is less than 10% by mass, the crystallinity becomes insufficient and the moldability and heat resistance deteriorate. On the other hand, when the copolymerization amount of the high melting point crystalline polymer segment (a) exceeds 50% by mass, the transparency aimed at in the present invention is not sufficiently exhibited.

[0019] The polyester block copolymer (A) used in the present invention can be produced by known methods. For example, a method of subjecting a lower alcohol diester of a dicarboxylic acid, an excessive amount of a low molecular weight glycol, and a low melting point polymer segment component to a transesterification reaction in the presence of a catalyst, and polycondensing the resulting reaction product. Alternatively, a method of subjecting a dicarboxylic acid, an excessive amount of a glycol, and a low melting point polymer segment component to an esterification reaction in the presence of a catalyst, and polycondensing the resulting reaction product. Further, a method of previously preparing a high melting point crystalline segment, adding a low melting point segment component thereto, and randomizing it by a transesterification reaction. A method of connecting a high melting point crystalline segment and a low melting point polymer segment with a chain linking agent. Furthermore, when poly(ε-caprolactone) is used as the low melting point polymer segment, any method such as adding an ε-caprolactone monomer to the high melting point crystalline segment by an addition reaction may be employed.

[0020] In the resin composition of the present invention, it is preferable to contain an alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms. More preferably, it is an aliphatic carboxylic acid having 10 to 20 carbon atoms. Most preferably, it is an aliphatic carboxylic acid having 10 to 15 carbon atoms. An alkali metal salt of an aliphatic carboxylic acid having 9 or less carbon atoms is preferable in that transparency can be improved with a small amount of blending, but bleeding out may occur due to the short carbon chain. The alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms is used as a clarifying agent having an action of making the polyester elastomer resin composition transparent. An aliphatic carboxylic acid is a compound having a carboxyl group attached to a linear or branched aliphatic group, and may have an unsaturated group, an alicyclic group, an aromatic group, or other substituents such as a hydroxyl group or a phosphate ester group in a part of the bond.

[0021] Among aliphatic carboxylic acids, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, etc. are preferable, and among alkali metal salts, a sodium salt is preferable in terms of solubility in polyester elastomer and good crystal nucleation property.

[0022] The amount of alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (B) is preferably 0.01 to 3 parts by mass per 100 parts by mass of polyester block copolymer (A). More preferably, the amount of alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (B) added is 0.05 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass.

[0023] It is thought that if the amount of alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms exceeds 3 parts by mass, the amount of gas generated during processing will increase, which may affect the moldability.

[0024] The resin composition of the present invention contains an ethylene copolymer (C) having a carboxylic acid metal base in its side chain. The ethylene copolymer (C) having a carboxylic acid metal base in its side chain is obtained by neutralizing a copolymer of ethylene and an ethylene-based unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or fumaric acid with alkali metal ions, alkaline earth metal ions, or zinc ions. These are commercially available, for example, as "Sarlin" from DuPont or "Hymiran" from Mitsui Dow Polychemicals. Among these, those neutralized with alkali metal ions such as sodium, potassium, or lithium are preferred.

[0025] The amount of ethylene copolymer (C) having a carboxylic acid metal base in these side chains is 0.2 parts by mass or more and 20 parts by mass or less per 100 parts by mass of polyester block copolymer (A). Preferably, 0.5 to 15 parts by mass, and particularly preferably 1 to 10 parts by mass.

[0026] When the amount of ethylene copolymer (C) having a carboxylic acid metal base in the side chain is less than 0.2 parts by mass, light transmission and transparency are insufficient, and when it is 20 parts by mass or more, phase separation occurs, and it is thought that the mechanical properties and light transmission and transparency decrease.

[0027] Ethylene copolymers (C) having a carboxylate metal base in their side chains can improve the transparency of polyester elastomers when used in combination with alkali metal salts (B) of aliphatic carboxylic acids having 10 or more carbon atoms. Surprisingly, when used as a method to improve transparency, polyester elastomers containing only alkali metal salts (B) of aliphatic carboxylic acids having 10 or more carbon atoms bleed out due to heat and over time. However, polyester elastomers containing both alkali metal salts (B) of aliphatic carboxylic acids having 10 or more carbon atoms and ethylene copolymers (C) having a carboxylate metal base in their side chains suppress heat-induced bleed-out and reduce thermal discoloration. In other words, ethylene copolymers (C) having a carboxylate metal base in their side chains can suppress bleed-out and thermal discoloration when used in combination with alkali metal salts (B) of aliphatic carboxylic acids having 10 or more carbon atoms.

[0028] The resin composition of the present invention contains a hindered phenol-based radical scavenger (D) and a peroxide decomposer (E) composed of carbon and oxygen. The hindered phenol-based radical scavenger (D) and peroxide decomposer (E) are used as antioxidants to suppress thermal discoloration of the polyester elastomer resin composition. Furthermore, since the hindered phenol-based radical scavenger (D) and peroxide decomposer (E) act as nucleating agents, transparency is improved when used in combination with an alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (B) and / or an ethylene copolymer (C) having a carboxylic acid metal base in its side chain.

[0029] The amount of hindered phenol-based radical scavenger (D) consisting of carbon and oxygen is 0.05 parts by mass or more and less than 0.30 parts by mass per 100 parts by mass of polyester block copolymer (A). Preferably, it is 0.05 to 0.25 parts by mass, more preferably 0.05 to 0.20 parts by mass, and most preferably 0.05 to 0.15 parts by mass.

[0030] The amount of peroxide decomposing agent (E) added is 0.05 to 1.0 part by mass per 100 parts by mass of polyester block copolymer (A). Preferably, it is 0.05 to 0.75 parts by mass, more preferably 0.05 to 0.50 parts by mass, and most preferably 0.05 to 0.30 parts by mass.

[0031] The amount of hindered phenol radical scavenger (D) and peroxide decomposer (E) consisting of carbon and oxygen is important. If the amount of hindered phenol radical scavenger (D) and peroxide decomposer (E) is less than 0.05 parts by mass, the effect of preventing thermal degradation is poor. If the amount of hindered phenol radical scavenger (D) consisting of carbon and oxygen is 0.30 parts by mass or more, problems with discoloration due to heat, initial color tone, and appearance will occur. If the amount of peroxide decomposer (E) exceeds 1.0 part by mass, problems with bleed-out, discoloration due to heat, initial color tone, and appearance will occur.

[0032] The hindered phenol radical scavenger (D), consisting of carbon and oxygen, is preferably added during polymerization, but may also be added to the polyester block copolymer after polymerization.

[0033] The resin composition of the present invention may contain antioxidants other than the hindered phenol radical scavenger (D) and peroxide decomposer (E) consisting of carbon and oxygen, but it is preferable that it contains only the hindered phenol radical scavenger (D) and peroxide decomposer (E) consisting of carbon and oxygen.

[0034] Examples of hindered phenol radical scavengers (D) consisting of carbon and oxygen include tetrakis[methylene-3(3',5'-di-t-4'-hydroxyphenol)propionate]methane, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)mesitylene, 1,1,3-tri(4-hydroxy-2-methyl-5-t-butylphenyl)butane, 1,1-bis(3-t-butyl-6-methyl-4-hydroxyphenyl)butane, 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid, pentaerythritol tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propanoate, 3-(4-H Examples include octyl droxy-3,5-diisopropylphenyl)propionate 2,4-dimethyl-6(-1-methylpentadecyl)phenol, bis(3-t-butyl-4-hydroxy-5-methylbenzenepropanoic acid)ethylenebis(oxyethylene), 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 4,4',4''-(1-methylpropanyl-3-inden)tris(6-t-butyl-m-cresol), 6,6'-di-t-butyl-4,4'-butylidene di-m-cresol, octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].

[0035] As the peroxide decomposing agent (E), phosphorus-based peroxide decomposing agents and sulfur-based peroxide decomposing agents are preferred. Since some phosphorus-based peroxide decomposing agents are hygroscopic, sulfur-based antioxidants are more preferred from a handling standpoint.

[0036] Phosphorus-based peroxide decomposing agents (E) include 3,9-bis(p-nonylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tri(mononylphenyl)phosphite, triphenoxyphosphine, isodecylphosphite, and bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester. Phosphate, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, trisnonylphenyl phosphite, tricresyl phosphite, triethyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris(tridecyl) phosphite, trioleyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl Mono(tridecyl) phosphite, trilauryl trithiophosphite, diethyl hydrogen phosphite, bis(2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, tetra(C12~C15 alkyl)-4,4'-isopropylidene Diphenyl phosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, triisooctyl phosphite, triisodecyl phosphite, trioctadecyl phosphite, tetraphenyltetratridecyl pentaerythritol tetraphosphite, diethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphoric acid, phenyl diisodecyl phosphite, diphenyldecyl phosphite, diphenylisodecyl phosphite, diphenyl(tridecyl) phosphite, tris(cyclohexylphenyl) phosphite, tris(4-phenylphenol) phosphite, diphenylnonylphenyl phosphite, di(nonylphenyl)dinonylphenyl phosphite, tetrakis(2,4-di-tert-butylphenyl 4,4'-biphenylenediphosphonite), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis[2-t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, diisodecylpentaerythritol phosphite Examples include phytes, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrairubi(2,4-di-t-butylphenyl) phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, triphenyl phosphite, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris(nonylphenyl) phosphite, cyclic neopentanetetrairubi(2,4-di-t-butyl-4-methylphenyl) phosphite, and cyclic neopentanetetrairbis(octadecyl) phosphite.

[0037] As sulfur-based peroxide decomposing agents (E), dilaurylthiopropionate, distearyltheodipropionate, laurylsteaaryltheodipropionate, dimyristylthiodipropionate, dioctadecyl 3,3'-thiodipropionate, dioctadecyl 3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, dilauryl-3,3-thiodipropionate, dimyristyl-3,3'-thiodipropionate, dilaurylthiodipropionate, ditridecylthiodipropionate Examples include dimycythyl thiodipropionate, lauryl stearyl thiodipropionate, distearyl thiodipropionate, distearyl-β,β'-thiodibutyrate, 3,3'-thiodipropionic acid, pentaerythritol tetra(β-lauryl thiopropionate ester), bis[3,3'-bis(4'-hydroxy-3'-tert-butylphenyl)butyric acid] glycol ester, and thiodiethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].

[0038] The resin composition of the present invention has a haze value of 85% or less, as measured on a 2mm thick sheet. If the haze value exceeds 85%, the transparency is insufficient.

[0039] The resin composition of the present invention preferably has a color value b of 10 or less.

[0040] The resin composition of the present invention exhibits a color difference ΔE of 0.1 to 5.0 when subjected to the thermochromicity test (heat treatment at 140°C for 24 hours) described below using a 2 mm thick sheet.

[0041] If weather resistance is required for the resin composition of the present invention, it is preferable to add an ultraviolet absorber (F) and a hindered amine compound (G) in which the amine is a tertiary amine.

[0042] UV absorbers (F) are substances that absorb in the ultraviolet region. They absorb UV light before it can act on the polymer chains, converting it into harmless substances such as heat, thus preventing the degradation of the polymer chains themselves. Hindered amine compounds (G), in which the amine is a tertiary amine, are used to capture radicals generated by UV light. However, if the amine is a primary or secondary amine, while weather resistance is improved, discoloration due to heat occurs.

[0043] The UV absorber (F) and the hindered amine compound (G), whose amine is a tertiary amine, have different mechanisms for suppressing discoloration caused by light, and therefore a synergistic effect is produced when they are combined. Furthermore, the addition of the UV absorber (F) and the hindered amine compound (G), whose amine is a tertiary amine, acts as a nucleating agent, and transparency is improved when used in combination with an alkali metal salt of an aliphatic carboxylic acid with 10 or more carbon atoms (B) and / or an ethylene copolymer (C) having a carboxylic acid metal base in its side chain.

[0044] For example, UV absorbers (F) that can be incorporated into the polyester thermoplastic elastomer used in the present invention include 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, pt-butylphenyl salicylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzylphenyl)benzotriazole, and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl) Examples include -5-chloroben azotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2,5-bis-[5'-t-butylbenzoxazolyl-(2)]-thiophene, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-hydroxy-4-i-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, and phenyl salicylate.

[0045] The ultraviolet absorber (F) is preferably one or more compounds selected from the group consisting of benzotriazole compounds, triazine compounds, and cyanoacrylate compounds. In particular, to improve appearance, an ultraviolet absorber with low absorbance in the wavelength range of 360 mm or more, which is the visible light range, is preferred.

[0046] As hindered amine compounds (G) in which the amine is a tertiary amine, polymers of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, bis(2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1-[2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, mono(1,2,2,6, Examples include 6-pentamethyl-4-piperidyl), dimethyl succinate·1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and 2-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-2-butylpropanediate bis[1,2,2,6,6-pentamethyl-4-piperidinyl].

[0047] Among hindered amine compounds (G) whose amine classification is tertiary amine, a structure in which all atoms bonded to the nitrogen atom are carbon atoms is preferred.

[0048] The amount of ultraviolet absorber (F) and hindered amine compound (G), in which the amine is a tertiary amine, is preferably 0.1 to 5 parts by mass, each per 100 parts by mass of polyester block copolymer (A). More preferably, it is 0.1 to 2.5 parts by mass, and particularly preferably 0.1 to 1.0 part by mass.

[0049] The resin composition of the present invention may contain light stabilizers other than the ultraviolet absorber (F) and the hindered amine compound (G) whose amine is a tertiary amine, but it is preferable that it contains only the ultraviolet absorber (F) and the hindered amine compound (G) whose amine is a tertiary amine.

[0050] Various other additives can be added to the resin composition of the present invention. As additives, resins other than those of the present invention, flame retardants, inorganic fillers, stabilizers, and antioxidants that are widely used as additives to polyester block copolymers can be added within a range that does not impair the characteristics of the present invention (a haze value of 85% or less measured on a 2 mm thick sheet, and a color difference ΔE of 0 to 5.0 when a 2 mm thick sheet is heat-treated at 140°C for 24 hours).

[0051] In addition, other additives such as coloring pigments, inorganic and organic fillers, coupling agents, tack enhancers, quenchers, stabilizers such as metal deactivators, and polyfunctional glycidyl group-containing styrene polymers may also be added.

[0052] The resin composition of the present invention preferably comprises 80% by mass or more in total, of (A), a polyether ester block copolymer (A), an alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (B), an ethylene copolymer having a carboxylic acid metal base in the side chain (C), a hindered phenol radical scavenger (D) and peroxide decomposer (E) consisting of carbon and oxygen, an ultraviolet absorber (F), and a hindered amine compound (G) in which the amine is a tertiary amine. More preferably, the total of (A), (C), (D), (E), or (A), (C), (D), (E), (F), (G), or (A), (B), (C), (D), (E), (F), (G) is 90% by mass or more, and even more preferably 95% by mass or more.

[0053] The method for producing the resin composition of the present invention is not particularly limited, but can be appropriately employed, for example, by supplying a raw material mixture containing a polyester block copolymer, an alkali metal aliphatic carboxylate salt having 10 or more carbon atoms, an ethylene copolymer having a metal carboxylate base in its side chain, a hindered phenol radical scavenger consisting of carbon and oxygen, a peroxide decomposer, and other additives to a screw-type extruder and melting and kneading it; or by first supplying a polyester block copolymer to a screw-type extruder and melting it, and then supplying and kneading an alkali metal aliphatic carboxylate salt having 10 or more carbon atoms, an ethylene copolymer having a metal carboxylate base in its side chain, a hindered phenol radical scavenger consisting of carbon and oxygen, a peroxide decomposer, and other additives through another supply port.

[0054] The resin composition of the present invention is molded by conventional melt molding methods, such as injection molding and extrusion molding, and used for various applications. It can also be used as fibers, films, sheets, tubes, etc. Furthermore, due to its excellent transparency and colorfastness, it can be used in automotive interior parts, electrical appliances, and other applications. [Examples]

[0055] The effects of the present invention will be explained below with reference to examples. In the examples, percentages and parts are all based on mass unless otherwise specified. Furthermore, the physical properties shown in the examples were measured as follows.

[0056] • Melting point A differential scanning calorimeter (TA Instruments DSC Q1000) was used to measure the peak temperature of the melting point when heated at a heating rate of 10°C / min under a nitrogen gas atmosphere.

[0057] • Surface hardness (Shore D scale) Measurements were taken in accordance with JIS K-7215.

[0058] • Total light transmittance and haze value Using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd., test specimens measuring 125 mm x 75 mm and 2 mm thick were prepared at 220°C (mold temperature: 40°C). The surface roughness of the test specimens was measured using a VK-9700 manufactured by Keyence and was found to be 0.46 μm. Using these test specimens, measurements were taken according to ASTM D1003 using a DIRECT READING HAZEMETER manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0059] • Measurement of color value b and color change (color difference ΔE) Using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd., test specimens measuring 125 mm x 75 mm and 2 mm thick were prepared at 220°C (mold temperature: 40°C). Using these test specimens, L*, a*, and b* were measured in accordance with JIS Z8722 using an SM-T color meter (light source: C, field of view: 2 degrees) manufactured by Suga Test Instruments Co., Ltd., while the specimens were held down on a white plate. The value of b* was defined as the color value b. L*, a*, and b* were measured before and after the thermal degradation test and weather resistance test described later, and the color difference ΔE was calculated. The formula for calculating ΔE is ΔE = [(ΔL*)] 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 That is the case.

[0060] • Thermal discoloration test Test specimens measuring 125 mm x 75 mm and 2 mm thick, prepared under the conditions described above, were heat-treated at 140°C for 24 hours using an ESPEC GPH(H)-202 gear oven. The color of the test specimens was observed visually, and the color difference ΔE was calculated using the SM-T colorimeter.

[0061] • Weather resistance test A 125mm x 75mm, 2mm thick test specimen, prepared under the previously described conditions, was subjected to 150 hours of treatment using a Suga Test Instruments S80HB sunshine weather meter (black panel temperature: 63°C, no rain, illuminance: 255 w / m²). 2 The color tone of the treated test specimens was observed visually, and the color difference ΔE was calculated using the SM-T colorimeter.

[0062] Reference example Production of polyester block copolymer (A-1) 278 parts terephthalic acid, which will form a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester, 686 parts poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 1400, which will form a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, as well as 316 parts 1,4-butanediol and 0.1 parts titanium tetrabutoxide were charged together in a reaction vessel equipped with helical ribbon-type stirring blades, and the esterification reaction was carried out by heating at 190-225°C for 3 hours while distilling off the reaction water from the system. After adding 0.10 parts by mass of "IRGANOX" 1330 (a hindered phenol radical scavenger manufactured by BASF consisting of carbon and oxygen, a hindered phenol radical scavenger that does not contain primary or secondary amines) (D-1) to 100 parts by mass of the polyester block copolymer component, the temperature was raised to 245°C, and then the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out under these conditions for 2 hours and 45 minutes. The resulting polymer was extruded into water in strand form and cut to form pellets.

[0063] Production of polyester block copolymer (A-2) 278 parts terephthalic acid, which will form a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester, 686 parts poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 1400, which will form a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, as well as 316 parts 1,4-butanediol and 0.1 parts titanium tetrabutoxide were charged together in a reaction vessel equipped with helical ribbon-type stirring blades, and the esterification reaction was carried out by heating at 190-225°C for 3 hours while distilling off the reaction water from the system. After adding 0.25 parts by mass of "IRGANOX" 1330 (a hindered phenol radical scavenger manufactured by BASF consisting of carbon and oxygen, a hindered phenol radical scavenger that does not contain primary or secondary amines) (D-1) to 100 parts by mass of the polyester block copolymer component, the temperature was raised to 245°C, and then the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out under these conditions for 2 hours and 45 minutes. The resulting polymer was extruded into water in strand form and cut to form pellets.

[0064] Production of polyester block copolymer (A-3) 374 parts terephthalic acid, which will form a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester, 610 parts poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 1400, which will form a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, along with 335 parts 1,4-butanediol and 0.2 parts titanium tetrabutoxide, were charged into a reaction vessel equipped with a helical ribbon-type stirring blade, and the esterification reaction was carried out by heating at 190-225°C for 3 hours while distilling off the reaction water from the system. After adding 0.10 parts by mass of "IRGANOX" 1330 (a hindered phenol radical scavenger manufactured by BASF consisting of carbon and oxygen, a hindered phenol radical scavenger that does not contain primary or secondary amines) (D-1) to 100 parts by mass of the polyester block copolymer component, the temperature was raised to 245°C, and then the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out under these conditions for 2 hours and 45 minutes. The resulting polymer was extruded into water in strand form and cut to form pellets.

[0065] Production of polyester block copolymer (A-4) 374 parts of terephthalic acid terephthalic acid, which will form a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester, 610 parts of poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 1400, which will form a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, along with 335 parts of 1,4-butanediol and 0.2 parts of titanium tetrabutoxide, were charged into a reaction vessel equipped with a helical ribbon-type stirring blade, and the esterification reaction was carried out by heating at 190-225°C for 3 hours while distilling off the reaction water from the system. After adding 0.05 parts by mass of "IRGANOX" 1098 (BASF's secondary amine-containing (non-carbon and oxygen) hindered phenol radical scavenger) (D-3) to 100 parts by mass of the polyester block copolymer component, the temperature was raised to 245°C, and then the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and polymerization was carried out under these conditions for 2 hours and 45 minutes. The resulting polymer was extruded into water in strand form and cut to form pellets.

[0066] Production of polyester block copolymer (A-5) 234 parts of terephthalic acid, which forms a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester, 754 parts of poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 2000, which forms a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, along with 228 parts of 1,4-butanediol and 0.2 parts of titanium tetrabutoxide, were charged into a reaction vessel equipped with a helical ribbon-type stirring blade, and the esterification reaction was carried out by heating at 190-225°C for 3 hours while distilling off the reaction water from the system. 0.50 parts by mass of "IRGANOX" 1330 (IR1330, a hindered phenol radical scavenger manufactured by BASF consisting of carbon and oxygen, a hindered phenol radical scavenger that does not contain primary or secondary amines) (D-1) was added to 100 parts by mass of polyester block copolymer component. The temperature was then raised to 245°C, and the pressure in the system was reduced to 0.2 mmHg over 50 minutes. Polymerization was carried out under these conditions for 3 hours and 30 minutes. The resulting polymer was extruded into water in strand form and cut to form pellets.

[0067] Table 1 shows the compositions of A-1, A-2, A-3, A-4, and A-5, as well as the amount and properties of the hindered phenol-based radical scavenger used.

[0068] [Table 1]

[0069] The polyester block copolymers (A-1), (A-2), (A-3), (A-4), and (A-5) shown in the reference examples contain radical scavengers (D) (D-1) or (D-3) during polymerization. However, the following examples show the blending ratio relative to 100 parts by mass of polyester block copolymer component (A) excluding the radical scavenger (D) added during polymerization.

[0070] Examples 1-5 The polyester block copolymers (A-1), (A-2), and (A-3) obtained in the reference example are combined with a hindered phenol radical scavenger consisting of carbon and oxygen (BASF's "IRGANOX" 1010) (D-2), an alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (Nitto Chemical Industries, Ltd.'s NS-3A (sodium laurate)) (B-1) or (Nitto Chemical Industries, Ltd.'s sodium stearate) (B-2), and a side chain having a sodium carboxylate base. Ethylene copolymer (DuPont "Sarlin" AD8610) (C-1) or (Mitsui Dow Polychemicals Co., Ltd. "Hymiran" 1707) (C-2), phosphorus-based peroxide decomposer (ADEKA Corporation "ADEKA Stab" PEP-8) (E-1), or sulfur-based peroxide decomposer (Daiichi Kogyo Seiyaku Co., Ltd. "Rasmit" LG) (E-2) were dry-blended in the proportions shown in Table 2. The mixture was then melt-kneaded and pelletized using a twin-screw extruder with a cylinder diameter of 45 mmφ. After drying these pellets at 80°C for 3 hours, test specimens measuring 125 mm × 75 mm and 2 mm thick were prepared using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd. at 220°C (mold temperature: 40°C). The obtained 2 mm thick sheet was used to measure total light transmittance and haze value, as well as to check for bleed-out and measure surface hardness and color value b. Furthermore, the previously described thermal discoloration test was performed. The results are shown in Table 3.

[0071] Note that (D-1) and (D-3) in Table 2 refer to the radical scavengers (D) contained in the polyester block copolymer (A) during polymerization, as shown in the reference example above. They are enclosed in parentheses to distinguish them from D-2, which is added after polymerization of the polyester block copolymer (A).

[0072] Comparative Examples 1-4 Polyester block copolymers (A-3), (A-4), or (A-5) obtained in the reference example were dry-blended with alkali metal salts of aliphatic carboxylic acids having 10 or more carbon atoms (NS-3A (sodium laurate) manufactured by Nitto Chemical Industries, Ltd.) (B-1) or (sodium stearate manufactured by Nitto Chemical Industries, Ltd.) (B-2), ethylene copolymers having a sodium carboxylate base in the side chain ("Sarlin" AD8610 manufactured by DuPont) (C-1) or ("Hymiran" 1707 manufactured by Mitsui Dow Polychemical Co., Ltd.) (C-2), phosphorus-based peroxide decomposer ("ADEKA Stab" PEP-8 manufactured by ADEKA Corporation) (E-1), or sulfur-based peroxide decomposer ("Rasmit" LG" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (E-2) in the proportions shown in Table 2. The mixtures were then melt-kneaded and pelletized using a twin-screw extruder with a cylinder diameter of 45 mmφ. After drying the pellets at 80°C for 3 hours, test specimens measuring 125 mm × 75 mm and 2 mm thick were prepared using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd. at 220°C (mold temperature: 40°C). The total light transmittance and haze value were measured using the obtained 2 mm thick sheets, and the presence or absence of bleed-out was checked. Surface hardness and color value b were also measured. Furthermore, the thermochromicity test described above was performed. The results are shown in Table 3.

[0073] [Table 2]

[0074] [Table 3]

[0075] As is clear from Examples 1 to 5 in Tables 2 and 3, a resin composition obtained by blending a polyester block copolymer (A) mainly composed of 10 to 50% by mass of a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester units and 90 to 50% by mass of a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, with an ethylene copolymer (C) and / or an aliphatic carboxylate metal salt (B) having a carboxylate metal base in the side chain, a hindered phenol-based radical scavenger (D) consisting of carbon and oxygen, and a peroxide decomposing agent (E) within the scope of the present invention, exhibits excellent transparency, appearance, and heat discoloration resistance.

[0076] Comparative Example 1 showed that even a small amount of a hindered phenol radical scavenger (D-3) containing a secondary amine in the polyester block copolymer (A) resulted in significant thermal discoloration. Comparative Example 2 showed that even when a hindered phenol radical scavenger (D-1) consisting of carbon and oxygen was included per 100 parts by mass of polyester block copolymer (A), thermal discoloration was observed if the content was 0.30 parts by mass or more. Comparative Example 3 showed that when an alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms was included per 100 parts by mass of polyester block copolymer (A), bleed-out was observed. Comparative Example 4 showed that even when an alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms was blended within the scope of the present invention per 100 parts by mass of polyester block copolymer (A), bleed-out was observed after heat treatment if an ethylene copolymer (C) having a carboxylic acid metal base in its side chain was not included.

[0077] Examples 6-10 The polyester block copolymers (A-1), (A-2), and (A-3) obtained in the reference example were modified with alkali metal salts of aliphatic carboxylic acids having 10 or more carbon atoms (NS-3A (sodium laurate) manufactured by Nitto Chemical Industries, Ltd.) (B-1) or (sodium stearate manufactured by Nitto Chemical Industries, Ltd.) (B-2), ethylene copolymers having a sodium carboxylate base in the side chain ("Sarlin" AD8610 manufactured by DuPont) (C-1) or ("Hymiran" 1707 manufactured by Mitsui Dow Polychemical Co., Ltd.) (C-2), and phosphorus-based peroxide decomposing agent ("ADEKA Stab" PEP-8 manufactured by ADEKA Corporation) (E- 1) Alternatively, a sulfur-based peroxide decomposer (Daiichi Kogyo Seiyaku Co., Ltd. "Rasmit" LG) (E-2), a benzotriazole-based ultraviolet absorber (BASF "Tinuvin" 234) (F-1), a triazine-based ultraviolet absorber (BASF "Tinuvin" 1557) (F-2), a cyanocrate-based ultraviolet absorber (BASF "Uvinul" 3030) (F-3), and a hindered amine compound with a tertiary amine classification (BASF "Tinuvin" 144) (G-1) were dry-blended in the proportions shown in Table 4, melt-kneaded using a twin-screw extruder with a cylinder diameter of 45 mmφ, and then pelletized. After drying the pellets at 80°C for 3 hours, test specimens measuring 125 mm × 75 mm and 2 mm thick were prepared using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd. at 220°C (mold temperature: 40°C). The total light transmittance and haze value were measured using the obtained 2 mm thick sheets, and the presence or absence of bleed-out was checked. Surface hardness and color value b were also measured. Furthermore, the previously described thermochromicity test and weather resistance test were performed. The results are shown in Table 5.

[0078] Note that (D-1) and (D-3) in Table 4 refer to the radical scavengers (D) contained in the polyester block copolymer (A) during polymerization, as shown in the reference example above.

[0079] Comparative Examples 5-7 The polyester block copolymer obtained in the reference example (A-1), (A-4), or (A-5) is used with an alkali metal salt of an aliphatic carboxylic acid having 10 or more carbon atoms (NS-3A (sodium laurate) manufactured by Nitto Chemical Industries, Ltd.) (B-1) or (sodium stearate manufactured by Nitto Chemical Industries, Ltd.) (B-2), an ethylene copolymer having a sodium carboxylate base in the side chain ("Sarlin" AD8610 manufactured by DuPont) (C-1), and a peroxide decomposition agent ("ADEKA Stab" PEP-8 manufactured by ADEKA Corporation) (E-1). Ruiha (Daiichi Kogyo Seiyaku Co., Ltd. "Rasmit" LG) (E-2), a triazine-based ultraviolet absorber (BASF "Tinuvin" 1557) (F-2), a hindered amine compound with a tertiary amine classification (BASF "Tinuvin" 144) (G-1), or a hindered amine compound with a secondary amine classification (BASF "Chimasorb" 994) (G-2) were dry-blended in the proportions shown in Table 4. The mixture was then melt-kneaded and pelletized using a twin-screw extruder with a cylinder diameter of 45 mmφ. After drying these pellets at 80°C for 3 hours, test specimens measuring 125 mm × 75 mm with a thickness of 2 mm were prepared using an electric injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd. at 220°C (mold temperature: 40°C). The obtained 2 mm thick sheet was used to measure total light transmittance and haze value, as well as to check for bleed-out and measure surface hardness and color value b. Furthermore, the previously described thermal discoloration test and weather resistance test were performed. The results are shown in Table 5.

[0080] [Table 4]

[0081] [Table 5]

[0082] As is clear from Examples 6-10 in Tables 4 and 5, a resin composition obtained by blending a polyester block copolymer (A) mainly composed of 10-50% by mass of a high-melting-point crystalline polymer segment consisting of crystalline aromatic polyester units and 90-50% by mass of a low-melting-point polymer segment consisting of aliphatic polyether units and / or aliphatic polyester units, with an ethylene copolymer (C) and / or an aliphatic carboxylate metal salt (B) having a carboxylate metal base in the side chain, a hindered phenol radical scavenger (D) consisting of carbon and oxygen, a peroxide decomposer (E), an ultraviolet absorber (F), and a hindered amine compound (G) whose amine is a tertiary amine, within the scope of the present invention, exhibits excellent transparency, appearance, heat discoloration resistance, and weather resistance.

[0083] From Comparative Example 5, when the polyester block copolymer (A) contained a hindered amine compound (G-2) in which the amine is a secondary amine, thermal discoloration was observed. From Comparative Example 6, even when the polyester block copolymer (A) was blended with an ultraviolet absorber (F) and a hindered amine compound (G) in which the amine is a tertiary amine within the scope of the present invention, significant thermal discoloration was observed when even a small amount of a hindered phenol radical scavenger (D-3) consisting of carbon and oxygen but containing a secondary amine was included. From Comparative Example 7, when the polyester block copolymer (A) was blended with an ultraviolet absorber (F) and a hindered amine compound (G) in which the amine is a tertiary amine within the scope of the present invention, and a hindered phenol radical scavenger (D-1) consisting of carbon and oxygen was also blended, thermal discoloration was observed when the content of the hindered phenol radical scavenger (D-1) consisting of carbon and oxygen was 0.30 parts by mass or more. [Industrial applicability]

[0084] The resin composition of the present invention is useful as a molding material for molded products where flexibility and transparency are desired, as it not only has superior transparency and appearance compared to conventional polyester elastomer resin compositions, but also superior resistance to discoloration due to heat.

Claims

1. A polyester elastomer resin composition characterized by comprising 100 parts by mass of a polyester block copolymer (A) mainly composed of 10 to 50% by mass of a high-melting-point crystalline polymer segment (a) consisting of crystalline aromatic polyester units and 90 to 50% by mass of a low-melting-point polymer segment (b) consisting of aliphatic polyether units and / or aliphatic polyester units, 0.2 to 20 parts by mass of an ethylene copolymer (C) having a carboxylic acid metal base in its side chain, and 0.05 to 0.25 parts by mass of a hindered phenol-based radical scavenger (D) consisting of carbon and oxygen, and 0.05 to 1.0 parts by mass of a peroxide decomposing agent (E), having a haze value of 85% or less measured on a 2 mm thick sheet, and a color difference ΔE of 0.1 to 5.0 when a 2 mm thick sheet is heat-treated at 140°C for 24 hours.

2. The polyester elastomer resin composition according to claim 1, characterized in that it contains 0.1 to 5 parts by mass of an ultraviolet absorber (F) and 0.1 to 5 parts by mass of a hindered amine compound (G) having a tertiary amine classification, per 100 parts by mass of the polyester block copolymer (A).

3. The polyester elastomer resin composition according to claim 2, wherein the ultraviolet absorber (F) is one or more selected from the group consisting of benzotriazole compounds, triazine compounds, and cyanoacrylate compounds.

4. The polyester elastomer resin composition according to claim 1, comprising 0.01 to 3 parts by mass of an alkali metal salt (B) of an aliphatic carboxylic acid having 10 or more carbon atoms per 100 parts by mass of the polyester block copolymer (A).

5. A molded article comprising the polyester elastomer resin composition according to any one of claims 1 to 4.

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