JP2010254973A - Thermoplastic polyester elastomer resin composition and molded article composed of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic polyester elastomer resin composition which is flexible, rich in elasticity, excellent in bending-fatigue resistance, and excels in various processabilities of such as injection molding, extrusion molding, and blow molding, and to provide a molded article composed of the same. <P>SOLUTION: The thermoplastic polyester elastomer resin composition is constituted by melt-mixing 100 pts.wt. of a thermoplastic polyester elastomer (A), 0.1-25 pts.wt. of a non-modified polyolefine resin (B) having no polar functional group, and 0.1-25 pts.wt. of a glycidyl group-modified polyolefine resin (C) wherein the apparent viscosity at 250°C to a specific shear rate measured on the basis of ISO11443 satisfies a specific range. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermoplastic elastomer resin composition that is flexible, elastic, excellent in bending fatigue, and excellent in injection molding, extrusion molding, and blow molding, and a molded body comprising the same.

Thermoplastic polyester elastomers have excellent mechanical properties such as strength, impact resistance, elastic recovery, flexibility, and low and high temperature properties, and are thermoplastic and easy to mold. Widely used in fields such as parts and consumer goods. Injection molding, extrusion molding, blow molding, and the like are used as molding methods for thermoplastic polyester elastomers, but different material properties are given due to differences in each molding processing method. For example, in injection molding, the molding cycle is shortened and the dimensional accuracy is improved by rapid solidification. In extrusion molding and blow molding, in consideration of the formability at the time of melting, material design is performed in which the melt elasticity is increased and the solidification rate is decreased.

For example, blow molding and extrusion molding are used for molded articles such as cover boots, air ducts, and fuel tubes of constant velocity joint driving devices. Among them, a cover boot of a constant velocity joint drive device for an automobile is an application in which a thermoplastic polyester elastomer is widely used, and press blow molding is generally used. However, in addition to press blow molding, studies are being made on injection blow molding, which has both injection molding and blow molding methods. However, the material design differs depending on the molding method described above, making it suitable for injection molding and blow molding. There is a problem that there is no material having the above characteristics and a material satisfying the moldability is not obtained.

  Accordingly, various studies have been made to improve moldability. For example, a polyester resin containing a reactive compound containing a glycidyl group and / or an isocyanate group and having a weight average molecular weight of 200 to 500,000. Modifier (for example, see Patent Document 1), modified polyester containing a small amount of polyolefin resin or polyamide resin in polyester resin by contacting polyester resin granules with polyolefin resin or polyamide resin under flow conditions A method for producing a resin (see, for example, Patent Document 2) has been proposed.

  However, these conventional techniques have not yet fully improved the molding technology, and it is difficult to achieve both improvement in defects such as sink marks during injection molding and blow moldability during blow molding. Met.

JP 2005-272680 A JP 2006-152315 A

  An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a thermoplastic polyester elastomer resin composition excellent in injection molding, extrusion molding, and blow moldability, as well as being flexible, elastic and excellent in bending fatigue. It is in providing the molded object using this.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have blended a thermoplastic polyester elastomer with a combination of an unmodified polyolefin resin having no polar functional group and an epoxy-modified polyolefin, and a specific shear rate. The inventors have found that the above object can be effectively achieved by making the apparent viscosity with respect to satisfy a specific range, and have reached the present invention.

That is, to achieve the above object, according to the present invention, 0.1 to 25 parts by weight of an unmodified polyolefin resin (B) having no polar functional group with respect to 100 parts by weight of the thermoplastic polyester elastomer (A), and The apparent viscosity at a temperature of 250 ° C. with respect to a specific shear rate measured by melting in accordance with ISO 11443 is 0.1 to 25 parts by weight of glycidyl group-modified polyolefin resin (C). A thermoplastic polyester elastomer resin composition characterized by satisfying (2) is provided.
0.8 <η _α / η _α-B <1 Formula (1)
η _β / η _β-B ≦ 0.8 Formula (2)
(Where η _α / η _α-B is a resin in which a thermoplastic polyester elastomer resin composition at a shear rate α: 60.8 (1 / s) and an unmodified polyolefin resin (B) having a branch are not blended) The apparent viscosity ratio with respect to the composition, and η _β / η _β-B is the ratio of the thermoplastic polyester elastomer (A) and the unmodified polyolefin resin (B) having a branch at a shear rate β: 6080 (1 / s). Ratio of apparent viscosity with blended resin composition.)

In the thermoplastic polyester elastomer resin composition of the present invention,
The thermoplastic polyester elastomer (A) comprises 20 to 70% by weight of a high-melting crystalline polymer segment composed of crystalline aromatic polyester units, and 80 to 30% by weight of a low-melting polymer segment composed of aliphatic polyether units. A polyester block copolymer having as a main component,
The unmodified polyolefin resin (B) having no functional group is polyethylene, or an α-olefin copolymer thereof,
Further, 0.01 to 5.0 parts by weight of the crystal nucleating agent (D) is blended,
The crystal nucleating agent (D) is an inorganic substance;
However, both are preferable conditions, and by applying these conditions, it can be expected to obtain a more excellent effect.

  The molded article of the present invention is characterized in that the thermoplastic polyester elastomer resin composition is molded.

  According to the present invention, taking advantage of the characteristics of a thermoplastic elastomer resin composition that is flexible, elastic, and excellent in bending fatigue, it has excellent processability in various molding methods such as injection molding, extrusion molding, and blow molding. A thermoplastic polyester elastomer resin composition and a molded body comprising the same can be obtained.

  Hereinafter, the present invention will be described in detail.

  The thermoplastic polyester elastomer (A) used in the present invention mainly comprises a high-melting-point crystalline polymer segment mainly composed of crystalline aromatic polyester units and a low-melting-point segment mainly composed of aliphatic polyether units. The high-melting crystalline polymer segment, which is a polyester block copolymer, is a polyester mainly formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  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. Acid, diphenoxyethane dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, sodium 3-sulfoisophthalate and the like. In the present invention, the aromatic dicarboxylic acid is mainly used. A part of the aromatic dicarboxylic acid is an alicyclic ring such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, or 4,4′-dicyclohexyldicarboxylic acid. Or aliphatic dicarboxylic acids such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. In addition, ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters such as dimethyl ester, diethyl ester, dipropyl ester, di-n-butyl ester, di-t-butyl, aryl esters, carbonates, and acid halides Of course, they can be used equally.

  Specific examples of the diol include 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, and 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] Cyclohex Aromatic diols such as 4,4′-dihydroxy-p-terphenyl and 4,4′-dihydroxy-p-quarterphenyl are preferred, and such diols are ester-forming derivatives such as acetylated, alkali metal salts. It can also be used in the form of

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

  A preferred example of such a high melting crystalline polymer segment is one comprising terephthalic acid or dimethyl terephthalate and polybutylene terephthalate units derived from 1,4-butanediol. The copolymerization amount of the high-melting crystalline polymer segment is usually 20 to 80% by weight, preferably 30 to 75% by weight.

  As the low-melting polymer segment used in the thermoplastic polyester elastomer (A) used in the present invention, an aliphatic polyether can be used as necessary.

  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, ethylene oxide and Examples include a copolymer of propylene oxide, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Of these, poly (tetramethylene oxide) glycol and / or poly (propylene oxide) glycol ethylene oxide adducts and / or copolymers of ethylene oxide and tetrahydrofuran are preferably used.

  The copolymerization amount of the low melting polymer segment of the thermoplastic polyester elastomer (A) used in the present invention is usually 80 to 20% by weight, preferably 70 to 25% by weight.

  The thermoplastic polyester elastomer (A) used in the present invention is obtained by melt polycondensation. The melt polycondensation can be carried out by a known method. For example, a method in which 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 are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, an excess amount of the dicarboxylic acid A method in which the glycol and low-melting-point polymer segment components are esterified in the presence of a catalyst and the resulting reaction product is polycondensed, and a high-melting-point crystalline segment is prepared in advance, and a low-melting-point segment component is added to this. Then, any method such as a method of randomizing by transesterification may be used.

  The thermoplastic polyester elastomer (A) obtained by melt polycondensation is then finely divided. Fine graining may be performed by a cold cut method in which the thermoplastic polyester elastomer (A) taken out in a gut shape or a sheet shape is pelletized with a cutter, or by a hot cut method in which pelletization is performed without forming a gut shape or a sheet shape. . Moreover, you may grind | pulverize the thermoplastic polyester elastomer (A) taken out in the lump shape.

  The thermoplastic polyester elastomer (A) obtained by melt polycondensation may then be subjected to solid phase polycondensation. The solid phase polycondensation is carried out at a temperature at which the thermoplastic polyester elastomer (A) finely divided after melt polycondensation does not fuse, but is usually carried out in a temperature range of 140 ° C to 220 ° C. Prior to solid phase polycondensation, it is desirable to go through a precrystallization and drying step. The solid phase polycondensation is carried out under high vacuum or under an inert air stream. In the case of high vacuum, it is preferably performed under a reduced pressure of 665 Pa or less, more preferably 133 Pa or less. In the case of an inert air stream, it is typically preferable to carry out under a nitrogen stream, and the pressure is not particularly limited, but atmospheric pressure is preferred. As the reaction vessel, it is preferable to use a rotatable vacuum dryer or a tower dryer capable of flowing an inert gas.

  The unmodified polyolefin resin (B) having no polar functional group used in the present invention is a polyolefin resin that does not contain a polar functional group in the molecule, and the apparent viscosity of the thermoplastic polyester elastomer (A) at a high shear rate. Although it will not specifically limit if the effect which lowers | hangs is given, Polyethylene or its alpha olefin copolymer is preferable. For example, polyethylene is classified by density difference, and low density polyethylene, medium density polyethylene, and high density polyethylene are known. It is also known that the density of polyethylene varies depending on the amount of α-olefin copolymerization component. Polyethylene produced by the production process during the polymerization reaction has a different molecular structure. Polyethylene obtained by radical polymerization under high pressure has a molecular structure containing short-chain branches and long-chain branches such as ethyl groups. Are known. Polyethylene produced by coordination anionic polymerization under medium and low pressures of several tens of atmospheres or less is known as linear high-density polyethylene. On the other hand, a copolymer obtained by copolymerizing α-olefin such as 1-butene and 1-hexene also has a molecular structure with a short-chain branch introduced and has a low density. And is further known as ultra-low density polyethylene.

  The blending amount of the unmodified polyolefin resin (B) having no polar functional group is 0.1 to 25 parts by weight, preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer (A). . If the amount is less than 0.1 part by weight, the viscosity cannot be lowered at a high shear rate. If the amount exceeds 25 parts by weight, the phase is separated from the thermoplastic polyester elastomer (A), and the bending fatigue property is deteriorated.

  The glycidyl group-modified polyolefin resin (C) used in the present invention is an olefin copolymer comprising an α-olefin and a glycidyl ester of an α, β-unsaturated acid. Examples of the α-olefin include ethylene, propylene and butene. -1 and the like are mentioned, among which ethylene is preferably used. Examples of the glycidyl ester of α, β-unsaturated acid include acrylic acid glycidyl ester, methacrylic acid glycidyl ester, and ethacrylic acid glycidyl ester. Among them, glycidyl methacrylate is preferably used. The copolymerization amount of α, β-unsaturated glycidyl ester is preferably in the range of 0.1 to 20 mol%. Further, if it is 40 mol% or less, unsaturated monomers copolymerizable with the above copolymer, for example, vinyl esters such as vinyl ethers, vinyl acetate, vinyl propionate, acrylic acid such as methyl, ethyl, propyl, butyl, and the like, and Methacrylic acid esters, acrylonitrile and styrene may be copolymerized. The blending amount of the glycidyl group-modified polyolefin resin (C) is 1 to 25 parts by weight, preferably 1 to 20 parts by weight, particularly preferably 1 to 15 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer (A). . If it is less than 0.1 part by weight, the high melt viscosity required for blow molding cannot be obtained, and if it exceeds 25 parts by weight, the oil resistance, grease resistance and bending fatigue resistance are deteriorated.

In the thermoplastic polyester elastomer resin composition of the present invention, the apparent viscosity at a temperature of 250 ° C. with respect to a specific shear rate measured according to ISO11443 satisfies the following formulas (1) and (2).
0.8 <η _α / η _α-B formula (1)
η _β / η _β-B ≦ 0.8 Formula (2)
(Where η _α / η _α-B is a resin in which a thermoplastic polyester elastomer resin composition at a shear rate α: 60.8 (1 / s) and an unmodified polyolefin resin (B) having a branch are not blended) The apparent viscosity ratio with the composition, and η _β / η _β-B is the unmodified polyolefin resin (B) having no polar functional group and the thermoplastic polyester elastomer (A) at a shear rate β: 6180 (1 / s). ) Is the ratio of the apparent viscosity to the unblended resin composition.)

When the apparent viscosity ratio η _α / η _α-B is 0.8 or less, the parison is deformed at the time of blow molding, and the blow moldability is deteriorated, for example, the shape after blow is defective. Further, when the apparent viscosity ratio η _β / η _β-B is 0.8 or more, the viscosity during injection molding is high, so that it is necessary to increase the molding lower limit pressure, which increases the burden on the molding machine. If the molding lower limit pressure is not increased, an unfilled portion of the resin tends to occur in a thin molded product or a large molded product, which is not preferable because the injection moldability deteriorates.

  The crystal nucleating agent (D) used in the present invention is not particularly limited as long as it is unmelted at the time of melt processing and can become a crystal nucleus in the cooling process, but is preferably an inorganic substance, particularly talc and calcium carbonate. preferable.

  Furthermore, the thermoplastic elastomer resin composition of the present invention includes hindered phenol-based, phosphorus-based, sulfur-based, aromatic amine-based antioxidants, ultraviolet absorbers, and the like as long as the purpose is not impaired. Light stabilizers such as HALS, antistatic agents, lubricants such as metal soaps and fatty acid amides, polyethers such as poly (tetramethylene oxide) glycol and lubricants such as liquid polybutadiene, plasticizers, dyes, pigments, flame retardants, release agents Additives such as molds and reinforcing materials such as mica, glass flakes, clay, barium sulfate, glass beads, glass fibers, and carbon fibers can be added.

  The thermoplastic polyester elastomer resin composition of the present invention is flexible, rich in elasticity and excellent in bending fatigue, and can be applied to different molding methods such as injection molding, extrusion molding and blow molding. It is suitable for a molding method that combines a plurality of molding techniques such as injection blow molding that combines molding and blow molding.

  The effects of the present invention will be described below with reference to examples. In the examples, “%” and “parts” are based on weight unless otherwise specified. The physical properties shown in the examples are measured by the following measuring methods.

[Hardness (Durometer D)]
Measured according to JIS K7215 durometer D hardness.

[Melting point and crystallization temperature]
DSC Q100 manufactured by TA Instruments Inc. was used, and the melting point was measured by heating from room temperature to 240 ° C. at a rate of temperature increase of 10 ° C./min. Further, after holding at 240 ° C. for 3 minutes, the solution was cooled to 40 ° C. at a temperature decreasing rate of 10 ° C./min, and the crystallization temperature was measured.

[Melt flow rate (MFR)]
From the melting point of the thermoplastic polyester elastomer (A), it was measured at a load of 2160 g according to ASTM D-1238 at a temperature of 230 ° C. determined by the formula (1).

[Bending fatigue]
A strip of length 75 mm x width 20 mm x thickness 2 mm was cut out from a square plate of length 75 mm x width 125 mm x thickness 2 mm obtained by injection molding, and an atmosphere at 100 ° C using a Toyo Seiki Seisakusho dimacha bending fatigue tester Below, the number of bends until a crack occurred by measuring a stroke between 25 mm and 5 mm between the chucks was measured.

[Apparent viscosity]
According to ISO 11443, using a capillograph manufactured by Toyo Seiki Seisakusho Co., Ltd., shear rate α = 60.8 (1 / second) when using a capillary with a length of 10 mm and a diameter of 1 mm at a temperature of 250 ° C., and β = 6180 (1 / sec) apparent viscosities η _α and η _β (Pa · sec) were evaluated.

[Injection moldability]
As an injection moldability, a JIS No. 2 dumbbell test piece and a square plate measuring 75 mm long x 125 mm wide x 2 mm thick were molded with an evaluation resin composition under conditions of a cylinder temperature of 240 ° C and a mold temperature of 50 ° C. The lower limit pressure at which the resin fills the mold was examined. The case where the lower limit pressure was less than 50 MPa was rated as ◯, and the case where the lower limit pressure was 50 MPa or more was rated as x.

[Blow moldability]
A hollow pipe having a bellows portion of five valleys and four valleys having a weight of 70 g, a crest outer diameter of 75 mm, a trough outer diameter of φ65 mm, and a wall thickness of 1.5 mm, using a press blow molding machine manufactured by Osberger. Is formed at a temperature of 250 ° C., and the degree of formation of the edge shape of the peak and valley is visually observed. The case where the edge is formed according to the mold dimension is indicated by ○, and the edge is formed according to the mold dimension. The case where there was a portion where the parison was deformed and the resin in the bellows part was folded over was marked as x.

[Reference Example 1]
[Method for producing thermoplastic polyester elastomer (A-1)]
44.4 parts of terephthalic acid, 38.6 parts of 1,4-butanediol and 43.9 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400, 0.04 part of titanium tetrabutoxide and mono-n-butyl -An esterification reaction was performed while charging 0.02 part of monohydroxytin oxide and a reaction vessel equipped with a helical ribbon type stirring blade, heating at 190 to 225 ° C for 3 hours, and allowing reaction water to flow out of the system. 0.2 part of tetra-n-butyl titanate was added to the reaction mixture, 0.05 part of “Irganox” 1098 (hindered phenol antioxidant manufactured by Ciba Geigy) was added, and the temperature was raised to 245 ° C. Then, the pressure in the system was reduced to 27 Pa over 50 minutes, and polymerization was performed for 2 hours and 10 minutes under the conditions. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained thermoplastic polyester elastomer (A-1) had a hardness of 50D, a melting point of 203 ° C., a crystallization temperature of 166 ° C., and an MFR of 6.0 g / 10 min.

[Method for producing thermoplastic polyester elastomer (A-2)]
The pellets of thermoplastic polyester elastomer (A-1) were charged into a rotatable reaction vessel, the pressure in the system was reduced to 27 Pa, and heated at 170 to 180 ° C. while rotating for 12 hours to perform solid phase polycondensation. . The obtained thermoplastic polyester elastomer (A-2) had a hardness of 50D, a melting point of 203 ° C., and a melt flow rate of 3.0 g / 10 min.

  The results of evaluating the physical properties of the flexural fatigue properties and the apparent viscosity of the thermoplastic polyester elastomers (A-1) and (A-2) are shown in Table 1 as Reference Examples 1 and 2.

  Moreover, the following were used as unmodified polyolefin resin (B) which does not have a polar functional group, glycidyl group modified polyolefin resin (C), and a crystal nucleating agent (D).

[Unmodified polyolefin resin (B) having no polar functional group]
(B-1) Low density polyethylene Novatec LF585M manufactured by Nippon Polyethylene Co., Ltd.
(B-2) High density polyethylene Hi-Zex 7000F manufactured by Prime Polymer Co., Ltd.
(B-3) Nippon Polyethylene Co., Ltd. hexene copolymer linear low density polyethylene Novatec SF941

[Glycidyl group-modified polyolefin resin (C)]
(C-1) Bond First E manufactured by Sumitomo Chemical Co., Ltd.

[Crystal nucleating agent (D)]
(D-1) Talc manufactured by Takehara Chemical Industry Co., Ltd.

[Example 1]
The thermoplastic polyester elastomer (A-1) obtained in the reference example is shown in Table 1 together with the unmodified polyolefin resin (B-1) having no polar functional group and the glycidyl group-modified polyolefin resin (C-1). The mixture was blended at a blending ratio (parts by weight) using a V-blender, melt kneaded at 250 ° C. using a twin screw extruder having a diameter of 45 mm and a triple thread type screw, and pelletized.

[Examples 2 to 7] and [Comparative Examples 1 to 3]
In the same manner as in Example 1 with the blending ratio shown in Table 1, pellets of Examples 2 to 7 and Comparative Examples 1 to 3 were obtained.

Using the obtained pellets, the physical properties of melting point, crystallization temperature, bending fatigue property and apparent viscosity were evaluated. As moldability, injection moldability and blow moldability were evaluated. The results are shown in Table 1. Here, the apparent viscosities η _α and η _β of Comparative Examples 1 to 3 correspond to η _α-B and η _β-B , respectively.

  Based on the above results, the thermoplastic polyester elastomer resin compositions of the present invention shown in Examples 1 to 7 were flexible, rich in elasticity, excellent in bending fatigue resistance, and excellent in injection moldability and extrusion moldability. It was. On the other hand, Comparative Examples 1 to 3 in which the polyolefin resin (B-1), (B-2), or (B-3) having no polar functional group is not blended can be blow-molded but injection-molded. In order to fill the resin up to the tip of the mold, it is necessary to increase the molding lower limit pressure, resulting in poor injection moldability.

  The thermoplastic polyester elastomer resin composition of the present invention can be used as various molded articles for automobiles, electronic / electrical equipment, precision equipment, and general consumer goods, taking advantage of the above-described excellent properties, such as injection molding, extrusion molding, It is suitable for applications using a molding method that combines various molding methods such as blow molding.

Claims (6)

0.1 to 25 parts by weight of an unmodified polyolefin resin (B) having no polar functional group and 0.1 to 25 parts by weight of a glycidyl group-modified polyolefin resin (C) with respect to 100 parts by weight of the thermoplastic polyester elastomer (A) A thermoplastic polyester elastomer resin characterized in that an apparent viscosity at a temperature of 250 ° C. for a specific shear rate measured in accordance with ISO 11443 satisfies the following formulas (1) and (2): Composition.
0.8 <η _α / η _α-B <1 Formula (1)
η _β / η _β-B ≦ 0.8 Formula (2)
(Here, η _α / η _α-B means that the thermoplastic polyester elastomer resin composition at a shear rate α: 60.8 (1 / s) and the unmodified polyolefin resin (B) having no polar functional group are not used. The apparent viscosity ratio with the blended resin composition, and η _β / η _β-B is an unmodified polyolefin resin (B) having a branch with the thermoplastic polyester elastomer (A) at a shear rate β: 6080 (1 / s). ) Is the ratio of the apparent viscosity to the unblended resin composition.) The thermoplastic polyester elastomer (A) comprises 20 to 70% by weight of a high-melting crystalline polymer segment composed of crystalline aromatic polyester units, and 80 to 30% by weight of a low-melting polymer segment composed of aliphatic polyether units. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the thermoplastic polyester elastomer resin composition is a polyester block copolymer having as a main component. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the unmodified polyolefin resin (B) having no functional group is polyethylene or an α-olefin copolymer thereof. Furthermore, 0.01-5.0 weight part of crystal nucleating agents (D) are mix | blended, The thermoplastic polyester elastomer resin composition of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The thermoplastic polyester elastomer resin composition according to claim 3, wherein the crystal nucleating agent (D) is an inorganic substance. A molded article obtained by molding the thermoplastic polyester elastomer resin composition according to any one of claims 1 to 5.