Thermoplastic elastomer resin composition

Abstract

To provide a thermoplastic elastomer resin composition which has high rigidity, and is excellent in low temperature impact resistance and flexural fatigue resistance.SOLUTION: A thermoplastic elastomer resin composition contains 50-95 wt.% of a polyether ester block copolymer (A) which mainly contains a high melting point crystalline polymer segment (a1) mainly composed of crystalline aromatic polyester and a low melting point crystalline polymer segment (a2) mainly composed of an aliphatic polyether unit, and 5-50 wt.% of a polybutylene terephthalate resin (B) and an amorphous resin (C).SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] A polyester block copolymer (thermoplastic polyester elastomer) having a crystalline aromatic polyester unit such as a polybutylene terephthalate unit as a hard segment and an aliphatic polyether unit such as a poly(alkylene oxide) glycol unit and / or a polylactone unit as a soft segment is excellent in many properties such as mechanical properties such as strength, impact resistance, elastic recovery, and flexibility, low-temperature and high-temperature characteristics, oil resistance, and chemical resistance. Therefore, it is widely used in fields such as automobiles, electrical and electronic parts, and consumer goods. Specific examples include its use in cover boots, air ducts, fuel tubes, etc. of constant velocity joint drive devices.

[0003] For the purpose of improving the properties of such polyester block copolymers, resin compositions containing polyester elastomers have also been developed. For example, a thermoplastic resin composition comprising a polyester elastomer with improved scratch resistance, an aromatic polycarbonate resin, and a lubricant (see Patent Document 1), a thermoplastic polyester resin composition comprising a polyester elastomer with improved flexibility, impact resistance, and fluidity, a polybutylene terephthalate resin, and an epoxidized modified block copolymer (see Patent Document 2), a polycarbonate resin composition comprising a polycarbonate resin with improved moldability, fluidity, transparency, and impact resistance, and a polyester elastomer (see Patent Document 3), a polyester resin composition comprising a polybutylene terephthalate resin with improved flexibility, moldability, and stain adhesion resistance, a crystalline polyester elastomer, a silicone compound, and a carbodiimide compound (see Patent Document 4), a thermoplastic resin composition comprising a styrene-based resin, a polycarbonate-based resin, and a polyester elastomer with improved chemical resistance (see Patent Document 5), and a flame-retardant polyester-based resin composition comprising a polyester-polyester elastomer with improved mechanical properties, fluidity, and moldability, an aromatic polycarbonate resin, and red phosphorus (see Patent Document 6) have been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in these prior arts, although each individual characteristic is excellent, there is a problem that they cannot withstand practical use because they do not have all of high rigidity, high low-temperature impact resistance, and flexural fatigue resistance.

[0006] The present invention has been achieved as a result of studying to solve the problems in the above-described prior art.

[0007] Accordingly, an object of the present invention is to provide a thermoplastic elastomer having high rigidity, excellent low-temperature impact resistance, and flexural fatigue resistance.

Means for Solving the Problems

[0008] The present inventors have found that, in order to achieve the above object, by blending a polybutylene terephthalate resin and an amorphous resin with a polyether ester block copolymer, the above object can be effectively achieved, and thus the present invention has been reached.

[0009] That is, according to the present invention, there is provided a thermoplastic elastomer resin composition containing 50 to 95% by weight of a polyether ester block copolymer (A) mainly composed of a high melting point crystalline polymer segment (a1) mainly composed of a crystalline aromatic polyester and a low melting point polymer segment (a2) mainly composed of an aliphatic polyether unit, 5 to 50% by weight of a polybutylene terephthalate resin (B), and an amorphous resin (C).

Effects of the Invention

[0010] The present invention can obtain a thermoplastic elastomer resin composition having high rigidity, excellent low-temperature impact resistance, and flexural fatigue resistance.

Modes for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail.

[0012] The high melting point crystalline polymer segment (a1) of the polyether ester block copolymer (A) used in the present invention is a polyester mainly formed from an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative. Specific examples of the aromatic dicarboxylic acid 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, etc.

[0013] Although mainly using an aromatic dicarboxylic acid, if necessary, a part of the aromatic dicarboxylic acid may be substituted with an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, 4,4'-dicyclohexyldicarboxylic acid, or an aliphatic dicarboxylic acid such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. Ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters, aryl esters, carbonates, and acid halides, can of course be used equivalently.

[0014] As the diol, diols having a molecular weight of 400 or less, such as aliphatic diols such as 1,4 - butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, alicyclic diols such as 1,1 - cyclohexanedimethanol, 1,4 - dicyclohexanedimethanol, tricyclodecane dimethanol, aromatic diols such as 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, 4,4’ - dihydroxy - p - terphenyl, 4,4’ - dihydroxy - p - quaterphenyl are preferred, and such diols can also be used in the form of ester - forming derivatives, such as acetyl derivatives, alkali metal salts, etc. Two or more of these dicarboxylic acids and their derivatives or diol components may be used in combination.

[0015] The high - melting - point crystalline polymer segment (a1) of the polyether - ester block copolymer (A) is more preferably composed of polybutylene terephthalate units or a combination of polybutylene terephthalate units and polybutylene isophthalate units.

[0016] The low - melting - point polymer segment (a2) of the polyether - ester block copolymer (A) used in the present invention is an aliphatic polyether. Examples of the aliphatic polyether include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of poly(propylene oxide) glycol, copolymers of ethylene oxide and tetrahydrofuran, etc. Two or more polyether - ester block copolymers having different compositions may be used in combination.

[0017] The low melting point polymer segment (a2) of the polyether ester block copolymer (A) used in the present invention is preferably poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, and a copolymer glycol of ethylene oxide and tetrahydrofuran, and may be used alone or in combination of two or more.

[0018] The copolymerization amount of the low melting point polymer segment (a2) of the polyether ester block copolymer (A) used in the present invention is preferably 20 to 70% by weight, more preferably 25 to 65% by weight. In particular, when it is 20% by weight or less, the impact resistance at low temperature is insufficient, and when it is 70% by weight or more, the rigidity is insufficient, which is not preferable.

[0019] The polyether ester block copolymer (A) used in the present invention can be produced by a known method. 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 obtained reaction product, or 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 obtained reaction product, or 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, or a method of connecting a high melting point crystalline segment and a low melting point polymer segment with a chain linking agent, etc., any method may be adopted.

[0020] The polybutylene terephthalate resin (B) used in the present invention is a polymer obtained by a usual polymerization method such as subjecting terephthalic acid or its ester-forming derivative and 1,4-butanediol or its ester-forming derivative to a polycondensation reaction, and may contain other copolymer components within a range that does not impair the properties, for example, about 20 parts by weight or less.

[0021] Preferable examples of these polymers and copolymers include polybutylene terephthalate, polybutyl (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate / naphthalate), poly(butylene / ethylene) terephthalate, etc., and they may be used alone or in combination of two or more.

[0022] The polybutylene terephthalate resin (B) used in the present invention is not particularly limited as long as it can be melt-kneaded.

[0023] The amorphous resin (C) used in the present invention generally has glass-like properties, does not show a distinct melting point when heated, and only shows a glass transition temperature.

[0024] Examples of the amorphous resin include polycarbonate resins, polyphenylene ether resins, polyarylate, polysulfone, polyethersulfone, styrene resins, and amorphous polyethylene terephthalate copolymers (PETG). Among these, polycarbonate resins, styrene resins, and amorphous polyethylene terephthalate copolymers (PETG) are preferable from the viewpoint of compatibility with the polyether ester block copolymer.

[0025] Preferable amorphous resins (C) used in the present invention include polycarbonate resins, which are not particularly limited, but are obtained by the reaction of a dihydroxy compound with a carbonic acid ester such as phosgene or diphenyl carbonate. The dihydroxy compound may be an alicyclic compound or the like, but is preferably an aromatic compound (particularly a bisphenol compound).

[0026] For example, as the bisphenol compound, bisphenols [for example, bis(hydroxyaryl)C1-6 alkane; bis(hydroxyaryl)C4-10 cycloalkane; 4,4'-dihydroxydiphenyl ether; 4,4'-dihydroxydiphenyl sulfone; 4,4'-dihydroxydiphenyl sulfide; 4,4'-dihydroxydiphenyl ketone, etc.] can be mentioned. The preferred polycarbonate resin contains bisphenol A type polycarbonate.

[0027] As the preferred amorphous resin (C) used in the present invention, styrene resins can be mentioned, and although not particularly limited, any polymer containing a styrene structural unit, that is, an aromatic vinyl unit, is acceptable.

[0028] For example, aromatic vinyls such as styrene, α-methylstyrene, dimethylstyrene, vinyltoluene, and vinyl cyanides such as acrylonitrile and methacrylonitrile, and if necessary, other polymerizable monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate are graft polymerized to obtain an ABS resin, an AS resin obtained by copolymerizing the aromatic vinyl and vinyl cyanide exemplified above, an HI (high impact)-polystyrene resin obtained by copolymerizing the conjugated diene rubber and aromatic vinyl exemplified above, and a polystyrene resin composed of aromatic vinyl.

[0029] Also, from the viewpoint of improving the compatibility between the polyether ester block copolymer (A) and the above styrene resin, it is desirable to use an epoxy group-containing vinyl copolymer.

[0030] Examples of the epoxy group of the epoxy-containing styrene resin include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, etc., and among them, glycidyl methacrylate is preferred.

[0031] As a preferred amorphous resin (C) used in the present invention, an amorphous polyethylene terephthalate copolymer (PETG) can be mentioned. It is a copolyester in which a part of ethylene glycol, which is a glycol component constituting polyethylene terephthalate (PET), is replaced with 1,4-cyclohexanedimethanol. The proportion of 1,4-cyclohexanedimethanol in the glycol component is preferably about 25 to 35 mol%.

[0032] The compounding amounts of the polybutylene terephthalate resin (B) and the amorphous resin (C) used in the present invention are 5 to 50% by weight, preferably 10 to 40% by weight, and the respective compounding ratios of the polybutylene terephthalate resin (B) and the amorphous resin (C) are not particularly limited.

[0033] When the compounding amounts of the polybutylene terephthalate resin (B) and the amorphous resin (C) are less than 10% by weight, the rigidity is insufficient, and when it exceeds 50% by weight, the low-temperature impact resistance and flexural fatigue resistance become insufficient.

[0034] The thermoplastic elastomer resin composition of the present invention preferably has a flexural modulus of 400 MPa or more, more preferably 450 MPa or more, measured at a temperature of 23°C according to the method described in ASTM D790.

[0035] When the compounding amounts of the polybutylene terephthalate resin (B) and the amorphous resin (C) are small, the flexural modulus measured at a temperature of 23°C according to the method described in ASTM D790 becomes 400 MPa or less, and the rigidity is insufficient, which may not be preferable.

[0036] The thermoplastic elastomer resin composition of the present invention preferably has a notched Izod impact strength of 150 J / m notch or more, more preferably 200 J / m notch or more, measured at a temperature of -20°C according to the method described in ASTM D256.

[0037] When the compounding amounts of the polybutylene terephthalate resin (B) and the amorphous resin (C) are large, When the notched Izod impact strength measured at a temperature of -20 °C according to the method described in ASTM D256 is 150 J / m or less at the notch, the impact resistance may be insufficient, which is not preferable.

[0038] The thermoplastic elastomer resin composition of the present invention preferably has a flex fatigue resistance of 200,000 cycles or more, more preferably 300,000 cycles.

[0039] The thermoplastic elastomer resin composition of the present invention has a melt viscosity index (MFR) of 15 g / 10 min or less, more preferably 13 g / 10 min or less, measured at a load of 2160 g after heating at a temperature of 250 °C for 5 minutes according to the method described in ASTM D1238. If the melt viscosity index (MFR) measured at a load of 2160 g after heating at a temperature of 250 °C for 5 minutes according to the method described in ASTM D1238 is 15 g / 10 min or more, the flex fatigue resistance may be inferior, which is not preferable. Furthermore, antioxidants, ultraviolet absorbers, stabilizers, antistatic agents, lubricants, colorants, etc. can be added to the thermoplastic elastomer resin composition of the present invention as needed within a range that does not impair the purpose.

[0040] In particular, as the stabilizer (D), when a polycarbonate resin is blended, it may be preferable to add an acidic phosphate ester or the like for the purpose of suppressing the transesterification reaction during the melt mixing of the polyester ether block copolymer (A), the polybutylene terephthalate resin (B), and the polycarbonate resin.

[0041] Specific examples of suitable acidic phosphate esters may be mono-phosphate esters or di-phosphate esters, such as mono / dimethyl phosphate, mono / diethyl phosphate, mono / di-n-butyl phosphate, mono / dioctyl phosphate, mono / dioctadecyl phosphate, mono / diphenyl phosphate, mono / dioctyl phosphate, etc. Further, as other stabilizers, it may be preferable to add a carbodiimide compound or the like for the purpose of suppressing a decrease in the melt viscosity when a polyester ether block copolymer (A) and a polybutylene terephthalate resin and a styrene resin are melt-mixed.

[0042] Specific examples of suitable carbodiimide compounds include aliphatic carbodiimide compounds in which an aliphatic group is bonded to a carbodiimide group, alicyclic carbodiimide compounds in which an alicyclic group is bonded to a carbodiimide group, and aromatic carbodiimide compounds in which an aromatic group is bonded to a carbodiimide group, etc.

[0043] The thermoplastic elastomer resin composition of the present invention can preferably be formed into a molded body by extrusion molding or injection molding.

[0044] Regarding the manufacturing method of the thermoplastic elastomer resin composition of the present invention, for example, a method of supplying a raw material in which a polyether ester block copolymer (A), a polybutylene terephthalate resin (B) and an amorphous resin (C) are blended together to a screw-type extruder and melt-kneading, and a method of first supplying the polyether ester block copolymer (A) to the screw extruder and further supplying and kneading the polybutylene terephthalate resin (B) and the amorphous resin (C) from other supply ports can be appropriately adopted.

[0045] In particular, when melt-kneading, it is preferable to perform vacuum degassing treatment from the vent port of the extruder cylinder part, and to perform degassing treatment on the resin composition at a temperature of 80°C to 140°C at which substantial solid-phase polymerization does not occur.

[0046] [Use and Molded Body] The molded article containing the thermoplastic elastomer resin composition of the present invention is also included.

[0047] The molded article can be obtained by molding the thermoplastic elastomer resin composition of the present invention, and is not particularly limited, but either extrusion molding or injection molding is preferable.

[0048] The shape of the molded article is not particularly limited and can be selected according to the molding method etc. For example, it may be any of a one-dimensional form (e.g., linear, rod-shaped, etc.), a two-dimensional form (e.g., sheet-shaped, film-shaped, etc.), a three-dimensional form (e.g., a form having a concave portion, a convex portion, an uneven portion, etc.), etc.

[0049] The molded article may be a molded article of only the thermoplastic elastomer resin composition, or a composite molded article in which a member formed of the thermoplastic elastomer resin composition (hereinafter sometimes simply referred to as "member 1") and a member formed of another resin (G) (hereinafter sometimes simply referred to as "member 2") are adhered (or joined). In the composite molded article, member 1 and member 2 may be directly adhered without an adhesive layer.

[0050] The molded article is not particularly limited, but examples include automobiles, electronic devices, electrical devices, precision devices, and general consumer goods (or their parts).

[0051] In particular, according to the thermoplastic elastomer resin composition of the present invention, even a molded article having a complex shape or a long flow length can be efficiently manufactured.

[0052] From such a viewpoint, the thermoplastic elastomer resin composition of the present invention may be suitably used as a resin composition for manufacturing a cover boot (e.g., a cover boot for a constant velocity joint drive device of an automobile), an air duct, a fuel tube, a hinge (hinge parts), etc.

Examples

[0053] Hereinafter, the effects of the present invention will be described by way of examples. Note that Examples 8 to 10 shall be read as Reference Examples 2 to 4.The physical properties shown in the examples were measured as follows.

[0054] [Surface hardness (Durometer D)] It was measured at 23°C according to the method described in JIS K7215.

[0055] [Melt viscosity index (MFR)] It was measured under the conditions of a load of 2160 g after a residence time of 5 minutes at a temperature of 250°C according to the method described in ASTM D1238.

[0056] [Mechanical properties (tensile breaking strength, tensile breaking elongation, flexural strength, flexural modulus)] Using dumbbell test specimens obtained by injection molding, the tensile breaking strength and tensile breaking elongation at 23°C were measured according to the method described in JIS K7113. Using flexural test specimens obtained by injection molding, the flexural strength and flexural modulus at 23°C were measured according to the method described in ASTM D790.

[0057] [Izod impact strength] Using Izod impact test specimens obtained by injection molding, the Izod impact strength at -20°C was measured according to the method described in ASTM D256.

[0058] [Flexural fatigue resistance] From a rectangular plate with a length of 75 mm, a width of 125 mm, and a thickness of 2 mm obtained by injection molding, a strip with a length of 75 mm, a width of 20 mm, and a thickness of 2 mm was cut out. Using a Dymatcher flexural fatigue tester manufactured by Toyo Seiki Seisaku-sho, Ltd., in an atmosphere of 80°C, the distance between the chucks was stroked between 25 mm and 5 mm at a cycle of 300 times / minute, and the number of flexures until cracks occurred was measured.

[0059] [Reference example] [Polyether ester block copolymer (A)] [Polyester elastomer (A1)] 42 parts of terephthalic acid, 41 parts of 1,4-butanediol and 52 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of about 1400 were charged into a reaction vessel equipped with a helical ribbon type stirring blade together with 0.03 part of titanium tetrabutoxide and 0.01 part of mono-n-butyl-mono-hydroxytin oxide, and heated at 200 to 235 °C for 3 hours to carry out an esterification reaction while allowing the reaction water to flow out of the system. 0.15 part of tetra-n-butyl titanate was additionally added to the reaction mixture, and after adding 0.05 part of a hindered phenol antioxidant (manufactured by Ciba Geigy, "Irganox 1098"), the temperature was raised to 245 °C, and then the pressure inside the system was reduced to 27 Pa over 50 minutes, and polymerization was carried out under that condition for 1 hour and 50 minutes.

[0060] The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heated while rotating at 170 to 180 °C for about 50 hours to carry out solid-phase polymerization to obtain a polyester elastomer (A1) (hard segment / soft segment (mass ratio) = 48 / 52). The MFR of the obtained polyester elastomer (A1) was 4.4 g / 10 min.

[0061] [Polyester elastomer (A2)] 51 parts of terephthalic acid, 39 parts of 1,4-butanediol and 48 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of about 1400 were charged into a reaction vessel equipped with a helical ribbon type stirring blade together with 0.04 part of titanium tetrabutoxide and 0.02 part of mono-n-butyl-mono-hydroxytin oxide, and heated at 190 to 225 °C for 3 hours to carry out an esterification reaction while allowing the reaction water to flow out of the system. 0.2 part of tetra-n-butyl titanate was additionally added to the reaction mixture, and after adding 0.05 part of a hindered phenol antioxidant (manufactured by Ciba Geigy, "Irganox 1098"), the temperature was raised to 245 °C, and then the pressure inside the system was reduced to 27 Pa over 50 minutes, and polymerization was carried out under that condition for 1 hour and 50 minutes.

[0062] The obtained polymer was extruded into strands in water and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heating was carried out while rotating at 170 - 180 °C for about 25 hours to perform solid-phase polymerization, thereby obtaining a polyester elastomer (A2) (hard segment / soft segment (mass ratio) = 50 / 40). The MFR of the obtained polyester elastomer (A2) was 3.0 g / 10 min.

[0063] [Polyester elastomer (A3)] 51 parts of terephthalic acid, 44 parts of 1,4-butanediol, and 39 parts of poly(tetramethylene oxide) glycol with a number-average molecular weight of about 1400 were charged into a reaction vessel equipped with a helical ribbon-type stirring blade together with 0.04 part of titanium tetrabutoxide and 0.02 part of mono-n-butyl-mono-hydroxytin oxide, and heated at 190 - 225 °C for 3 hours to carry out an esterification reaction while allowing the reaction water to flow out of the system. 0.2 part of tetra-n-butyl titanate was additionally added to the reaction mixture, and after adding 0.05 part of a hindered phenol-based antioxidant ("Irganox 1098" manufactured by Ciba Geigy), the temperature was raised to 245 °C, and then the pressure inside the system was reduced to 27 Pa over 50 minutes, and polymerization was carried out under those conditions for 1 hour and 50 minutes.

[0064] The obtained polymer was extruded into strands in water and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heating was carried out while rotating at 170 - 180 °C for about 25 hours to perform solid-phase polymerization, thereby obtaining a polyester elastomer (A3) (hard segment / soft segment (mass ratio) = 60 / 40). The MFR of the obtained polyester elastomer (A3) was 3.9 g / 10 min.

[0065] [Polybutylene terephthalate resin (B)] "Trecon" 1401X06 manufactured by Toray Industries, Inc.

[0066] [Amorphous resin (C)] (C1) Polycarbonate resin "IUPILON" H-3000 manufactured by Mitsubishi Engineering-Plastics Corporation

[0067] (C2) Styrene resin AS resin. Acrylonitrile / styrene / glycidyl methacrylate copolymer. Styrene, acrylonitrile, and glycidyl methacrylate were suspension polymerized to prepare a bead-like modified vinyl copolymer. The weight ratio of each component of the acrylonitrile / styrene / glycidyl methacrylate copolymer is 23.9 / 75.8 / 0.3% by weight, and the reduced viscosity is 0.49

[0068] (C3) Amorphous polyethylene terephthalate copolymer "Eastar" Copolyester GN071 manufactured by Eastman Chemical Company [Stabilizer (D)] (D1) Transesterification inhibitor "ADEKA STAB" AX-71 manufactured by ADEKA Corporation

[0069] (D2) Melt viscosity stabilizer "Carbodilite" HMV-15CA manufactured by Nisshinbo Chemical Inc

[0070] [Example 1] The polyether ester block copolymer (A1) obtained in the reference example, polybutylene terephthalate resin (B), polycarbonate resin (C1) as an amorphous resin, and "ADEKA STAB" AX-71 (D1) manufactured by ADEKA Corporation as a stabilizer were dry blended at the compounding ratios (weight ratios) shown in Table 1. The dry blended compound was melt kneaded at 250°C using a twin-screw extruder having a cylinder diameter of 26 mmφ while performing vacuum degassing treatment from one vent port near the cylinder discharge port, and then pelletized

[0071] The obtained pellets were charged into a shelf-type hot air dryer and dried at 80°C for 3 hours to obtain a thermoplastic elastomer composition, and various properties were evaluated

[0072] The obtained thermoplastic elastomer resin composition was injection molded into JIS No. 2 dumbbell test pieces, flexural test pieces, Izod test pieces, and rectangular plate molded articles with a length of 75 mm, a width of 125 mm, and a thickness of 2 mm at a mold temperature of 50°C (mold cavity surface) using an in-line screw type injection molding machine set at 260°C. Table 1 shows the results of evaluating various properties using the obtained injection molded articles.

[0073] [Examples 2 to 10] Using (A1), (A2), (A3) as the polyester ether block copolymer (A), polybutylene terephthalate resin (B), (C1), (C2), (C3) as the amorphous resin (C), and (D1), (D2) as the stabilizer (D) at the compounding ratios shown in Table 1, a thermoplastic elastomer resin composition and injection molded articles were obtained in the same manner as in Example 1, and various properties were evaluated. The composition and properties are summarized in Table 1.

[0074] [Comparative Examples 1 to 7] Each component was dry blended at the compounding ratios shown in Table 2, pelletized and injection molded in the same manner as in Examples 1 to 10, and Table 2 shows the results of evaluating various properties in the same manner as in Examples 1 to 10 using the obtained injection molded articles.

[0075]

Table 1

[0076]

Table 2

[0077] From the above results, Examples 1 to 10, which are the thermoplastic elastomer resin compositions of the present invention, are materials with high rigidity, excellent low-temperature impact resistance, and flexural fatigue resistance.

[0078] On the other hand, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 5 have good low-temperature impact resistance but low rigidity, which is not preferable. Comparative Example 4 and Comparative Example 6 have high rigidity but low low-temperature impact resistance, which is not preferable. Comparative Example 6 also has low endurance flex fatigue resistance. Comparative Example 7 has high rigidity, and its low-temperature impact resistance is slightly good, but its endurance flex fatigue resistance is low.

Claims

1. A thermoplastic elastomer resin composition comprising 50 to 95% by weight of a polyether ester block copolymer (A) mainly composed of a high melting point crystalline polymer segment (a1) mainly composed of a crystalline aromatic polyester and a low melting point polymer segment (a2) mainly composed of an aliphatic polyether unit as main components, 5 to 50% by weight in total of a polybutylene terephthalate resin (B) and an amorphous resin (C), wherein the amorphous resin (C) contains a styrene-based resin and / or the amorphous resin (C) is a polycarbonate-based resin, and an ester exchange inhibitor (D1) is contained in an amount of 0.1 part by weight or more based on 100 parts by weight in total of the polyether ester block copolymer (A), the polybutylene terephthalate resin (B) and the amorphous resin (C).

2. The thermoplastic elastomer resin composition according to claim 1, wherein the high melting point crystalline polymer segment (a1) of the polyether ester block copolymer (A) is composed of a polybutylene terephthalate unit or a polybutylene terephthalate unit and a polybutylene isophthalate unit.

3. The thermoplastic elastomer resin composition according to claim 1 or 2, wherein the low melting point polymer segment (a2) of the polyether ester block copolymer (A) is at least one selected from poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, and a copolymer glycol of ethylene oxide and tetrahydrofuran.

4. The thermoplastic elastomer resin composition according to any one of claims 1 to 3, wherein the ratio of the hard segment to the soft segment of the high melting point crystalline polymer segment mainly composed of a crystalline aromatic polyester and the low melting point polymer segment mainly composed of an aliphatic polyether unit in the polyether ester block copolymer (A) is hard segment / soft segment (mass ratio) = 80 / 20 to 40 / 60.

5. The thermoplastic elastomer resin composition according to any one of claims 1 to 4, having a flexural modulus of 400 MPa or more measured under the condition of a temperature of 23°C in accordance with ASTM D790, and having a notched Izod impact strength of 200 J / m notch or more measured under the condition of -20°C in accordance with ASTM D256.

6. The thermoplastic elastomer resin composition according to any one of claims 1 to 5, having an MFR of 15 g / 10 min or less measured under the conditions of a temperature of 250°C, a load of 2160 g, and a residence time of 5 minutes in accordance with ASTM D1238.

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