Thermoplastic polyester elastomer resin composition

Abstract

To provide a thermoplastic polyester elastomer resin composition having a low specific gravity, a low shrinkage, a low dielectric constant and low dielectric tangent property while having flexibility, impact resistance and good flowability as a polyester elastomer in a well-balanced manner.SOLUTION: There is provided a thermoplastic polyester elastomer resin composition which comprises: a thermoplastic polyester block copolymer (A) containing 20 to 85 mass% of (H) a hard segment mainly composed of a crystalline aromatic polyester unit and 15 to 80 mass% of (L) a soft segment mainly composed of an aliphatic polyether unit and / or an aliphatic polyester unit as constitutional components; a polyolefin-based resin (B) having a flexural modulus measured according to JIS K7171:2022 of less than 2000 MPa; and a styrene-based block copolymer (C) having an aromatic vinyl unit content of 20 to 50 mass%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Thermoplastic polyester elastomer resins, composed of polyester block copolymers with crystalline aromatic polyester units as hard segments and aliphatic polyether units such as poly(alkylene oxide) glycol as soft segments, offer an excellent balance of polyester resin mechanical properties such as strength, impact resistance, and elastic recovery, as well as good melt processability. They maintain their properties over a wide range of temperatures, from low to high, and also possess the flexibility and flexural fatigue resistance of elastomers. Therefore, they are used in a variety of applications, including machine parts, electrical and electronic components, automotive parts, home appliance parts, everyday items, and industrial materials. Lightweight (low specific gravity) materials are particularly sought after for automotive and home appliance parts, especially for electronic device applications.

[0003] Like other polyester resins, thermoplastic polyester elastomer resins undergo changes in the dimensions and shape of molded products after melt injection molding. Therefore, when used in integrated molded products with different materials, shrinkage distortion and warpage may occur in the molded product. In particular, when used in thin-walled shapes, molding shrinkage distortion and warpage of the resin after molding become significant, so reducing molding shrinkage is desired. In addition to the recent demand for lighter and smaller electronic devices, the rapid development of AI and IoT technologies has led to more sophisticated electronic device functions and faster communications speeds, which in turn has led to higher frequencies of electromagnetic waves, resulting in a tendency for information transmission loss to increase in high frequency bands. Therefore, there is a growing demand for lower dielectric constants and lower dielectric loss tangents in electronic devices used in high frequency bands.

[0004] Various studies have been conducted on thermoplastic polyester elastomer resins to reduce the specific gravity of molded articles obtained by injection molding and to improve the dimensional shrinkage of molded articles. For example, Patent Document 1 discloses a resin composition containing an unsaturated polyester, which is a condensation polymer of a polybasic acid component containing 90 mol% or more of an unsaturated organic diacid and a polyhydric alcohol component, a hydrogenated styrene-based thermoplastic elastomer, and a styrene monomer, together with a polymerization initiator. Patent Document 2 also discloses a thermoplastic elastomer composition obtained by reacting a radical-crosslinked ethylene-α-olefin copolymer with a rubbery polymer modified with a monomer having both an unsaturated bond and a carboxyl group or an acid anhydride, a polyester resin, and a modified olefin resin having an epoxy group or its derivative in the molecule.

[0005] Furthermore, a thermoplastic polyester resin composition in which a styrene component and an acrylonitrile component are graft-copolymerized into a polyester block copolymer and an acrylonitrile component is blended in a specific ratio with an acrylonitrile-butadiene-styrene resin (ABS resin) (for example, Patent Document 3), and a thermoplastic polyester resin in which an acrylonitrile-styrene (AS resin) and an acrylic-styrene copolymer are blended in a specific ratio with a thermoplastic polyester resin (for example, Patent Document 4) have been disclosed.

[0006] Additionally, a thermoplastic resin composition has been disclosed in which a specific polycarbonate resin and a polyester resin containing 50 mol % or more of alicyclic diol units as a diol component are blended in a specific ratio (for example, Reference 5). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-041470 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-285198 [Patent Document 3] Patent No. 5240680 [Patent Document 4] Patent No. 6869640 [Patent Document 5] Japanese Patent Publication No. 2023-093272 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a thermoplastic polyester elastomer resin composition having low specific gravity, low shrinkage, and low dielectric properties by blending a low specific gravity material that exhibits good dispersibility in the thermoplastic polyester elastomer. [Means for solving the problem]

[0009] Thermoplastic polyester elastomer resin compositions have an excellent balance between mechanical strength and flexibility and good melt processability, but they have a relatively high specific gravity among elastomers, and the molding shrinkage of the resulting molded articles is high. In addition, because they contain bonding units that cause polarization, mainly ester bonds, they are not sufficient in terms of low dielectric properties as a material.

[0010] The present inventors have discovered that the above-mentioned problems can be solved by blending a specific thermoplastic polyester block copolymer, a polyolefin resin having specific properties, and a styrene block copolymer having a specific configuration in a specific component ratio, and polymer-alloying the resulting resin composition, and by forming the resulting resin composition into a specific dispersion form. This has led to the present invention.

[0011] The present invention is not limited to the following embodiments, and may be modified or substituted by those skilled in the art. That is, the thermoplastic polyester elastomer resin composition of the present invention has the following configuration.

[0012] (1) A thermoplastic polyester elastomer resin composition comprising: a thermoplastic polyester block copolymer (A) comprising 20 to 85% by mass of hard segments (H) whose main structural units are crystalline aromatic polyester units; and 15 to 80% by mass of soft segments (L) whose main structural units are aliphatic polyether units and / or aliphatic polyester units; a polyolefin resin (B) having a flexural modulus of less than 2000 MPa as measured in accordance with JIS K7171:2022; and a styrene block copolymer (C) having an aromatic vinyl unit content of 20 to 50% by mass, wherein the thermoplastic polyester elastomer resin composition comprises 5 to 100 parts by mass of the polyolefin resin (B) and 5 to 50 parts by mass of the styrene block copolymer (C) per 100 parts by mass of the thermoplastic polyester block copolymer (A).

[0013] (2) The thermoplastic polyester elastomer resin composition according to (1), wherein the polyolefin resin (B) is at least one selected from the group consisting of polyethylene resin, polypropylene resin, and olefin elastomer resin.

[0014] (3) The thermoplastic polyester elastomer resin composition according to (1) or (2), wherein the styrene block copolymer (C) is a modified styrene thermoplastic elastomer, such as styrene-ethylene-butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-ethylene-propylene-styrene (SEPS), styrene-isoprene-styrene (SIS), or a combination of these block copolymers.

[0015] (4) The thermoplastic polyester elastomer resin composition according to any one of (1) to (3), characterized in that it contains 0.5 to 10 parts by mass of a polyamide copolymer (D) per 100 parts by mass of the thermoplastic polyester block copolymer (A), and the polyamide copolymer (D) is a two or more component polyamide copolymer in which at least polyamide 6 and / or polyamide 610 are combined.

[0016] (5) The thermoplastic polyester elastomer resin composition according to any one of (1) to (4), characterized in that the dielectric constant at a frequency of 1 MHz is 3.3 or less when measured using a 125 mm × 75 mm × 2 mm thick square plate in accordance with test method IEC62631-2-1 under an environment of 23°C and 50% RH, and the dielectric constant at a frequency of 10 GHz is 3.0 or less when measured using a 125 mm × 75 mm × 2 mm thick square plate cut to 80 mm × 1.5 mm × 1.5 mm under an environment of 23°C and 50% RH under test method IEC62810.

[0017] (6) The thermoplastic polyester elastomer resin composition according to any one of (1) to (5), characterized in that the tensile elongation at break measured in accordance with JIS K7161:2014 using a JIS No. 2 test piece after continuous exposure for 150 hours at a temperature of 121°C and a relative humidity of 100% RH in accordance with JIS C60068-2-66:2001 is 100% or more.

[0018] (7) The thermoplastic polyester elastomer resin composition according to any one of (1) to (6), characterized in that, in morphology observed at 5000x magnification using a transmission electron microscope (TEM), the thermoplastic polyester block copolymer (A) is a matrix and the polyolefin resin (B) is dispersed as domains via the styrene block copolymer (C). [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a thermoplastic polyester elastomer resin composition having a low specific gravity, low shrinkage, and low dielectric properties, and the composition can be suitably used in applications requiring both the flexibility and impact resistance of polyester elastomers and the aforementioned dielectric properties, such as electrical and electronic equipment parts, automotive electrical parts, and industrial materials. [Brief explanation of the drawings]

[0020] [Figure 1]FIG. 1 is a morphology observation diagram in an example using a transmission electron microscope (TEM). DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, the thermoplastic polyester elastomer resin composition of the present invention will be described in detail.

[0022] The thermoplastic polyester elastomer resin composition of the present invention comprises: The thermoplastic polyester elastomer resin composition contains a thermoplastic polyester block copolymer (A) having, as its constituent components, 20 to 85% by mass of hard segments (H) whose main constituent units are crystalline aromatic polyester units and 15 to 80% by mass of soft segments (L) whose main constituent units are aliphatic polyether units and / or aliphatic polyester units; a polyolefin resin (B) having a flexural modulus of less than 2000 MPa as measured in accordance with JIS K7171:2022; and a styrene block copolymer (C) having an aromatic vinyl unit content of 20 to 50% by mass. The thermoplastic polyester elastomer resin composition contains 5 to 100 parts by mass of the polyolefin resin (B) and 5 to 50 parts by mass of the styrene block copolymer (C) per 100 parts by mass of the thermoplastic polyester block copolymer (A).

[0023] [Thermoplastic polyester block copolymer (A)] The thermoplastic polyester block copolymer (A) of the present invention comprises, as constituent components, hard segments consisting of crystalline aromatic polyester units and soft segments consisting of aliphatic polyether units and / or aliphatic polyester units.

[0024] The hard segment is a polyester formed from an aromatic dicarboxylic acid or its ester bond-forming derivative (hereinafter sometimes referred to as the "acid component") and a diol or its ester bond-forming derivative (hereinafter sometimes referred to as the "diol component"). 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.

[0025] In the present invention, the aromatic dicarboxylic acids are primarily used, but a portion of these aromatic dicarboxylic acids may be replaced with alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, and 4,4'-dicyclohexyldicarboxylic acid, or aliphatic dicarboxylic acids such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. Furthermore, ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters, aryl esters, carbonate esters, and acid halides, may also be used.

[0026] Next, 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, and decamethylene glycol; alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, and tricyclodecane dimethanol; and aromatic diols such as xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxy)diphenylpropane, 2,2'-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxyethoxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4'-dihydroxy-p-terphenyl, and 4,4'-dihydroxy-p-quaterphenyl. These diols can also be used in the form of ester-forming derivatives, such as acetylated forms and alkali metal salts.

[0027] The soft segment used in the present invention is an aliphatic polyether and / or an aliphatic polyester. Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(trimethylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide adduct of poly(propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Among these, poly(tetramethylene oxide) glycol and / or an ethylene oxide adduct of poly(propylene oxide) glycol and / or a copolymer of ethylene oxide and tetrahydrofuran are preferably used.

[0028] Examples of the aliphatic polyester include poly(ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate, and polyethylene adipate.

[0029] Among these aliphatic polyethers and / or aliphatic polyesters, from the viewpoint of the elastic properties of the resulting polyester block copolymer, poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, a copolymer glycol of ethylene oxide and tetrahydrofuran, poly(ε-caprolactone), polybutylene adipate, polyethylene adipate, etc. are preferred, and among these, poly(tetramethylene oxide) glycol, an ethylene oxide adduct of poly(propylene oxide) glycol, and a copolymer glycol of ethylene oxide and tetrahydrofuran are particularly preferred. Furthermore, the number average molecular weight of these soft segments in the copolymerized state is preferably 600 to 6,000, more preferably 1,000 to 3,000, and even more preferably 1,000 to 2,000.

[0030] The thermoplastic polyester block copolymer (A) of the present invention comprises, as its constituent components, hard segments (H) consisting of crystalline aromatic polyester units and soft segments (L) consisting of aliphatic polyether units and / or aliphatic polyester units.

[0031] The thermoplastic polyester block copolymer (A) has a hard segment (H) composed of one selected from the above-mentioned acid components and one or more selected from the above-mentioned diol components. A preferred example of the hard segment (H) is a polybutylene terephthalate unit derived from terephthalic acid or dimethyl terephthalate and 1,4-butanediol.

[0032] In addition, the hard segment (H) of the thermoplastic polyester block copolymer (A) of the present invention may be composed of two or more types of acid components and one or more types of glycol components. In this case, it is referred to as hard segment (H2). Preferred examples of the hard segment (H2) include those composed of polybutylene terephthalate units derived from terephthalic acid and / or dimethyl terephthalate, and those composed of isophthalic acid and / or dimethyl isophthalate and polybutylene isophthalate units derived from 1,4-butanediol, and a thermoplastic polyester block copolymer (hereinafter referred to as A2) using two or more acid components can also be used.

[0033] The soft segment (L) is selected from the above-mentioned aliphatic polyethers and / or aliphatic polyesters.

[0034] The thermoplastic polyester block copolymer (A) contains 20 to 85 mass% of hard segments (H) and 15 to 80 mass% of soft segments (L), and preferably contains 35 to 80 mass% of hard segments (H) and 20 to 65 mass% of soft segments (L).

[0035] The melting point of the thermoplastic polyester block copolymer (A) is preferably 150° C. to 225° C., and more preferably 160° C. to 220° C. If the melting point of the thermoplastic polyester block copolymer (A) is higher than 225° C., the resulting thermoplastic polyester elastomer will not be able to sufficiently achieve both flexibility and low specific gravity and low shrinkage, while if the melting point is lower than 150° C., the resulting thermoplastic polyester elastomer will not have sufficient heat resistance, and the molding cycle time will increase, which is undesirable.

[0036] The thermoplastic polyester block copolymer (A) used in the present invention can be produced by a known method, specific examples of which include a method of transesterifying a lower alcohol diester of a dicarboxylic acid with an excess amount of a low-molecular-weight glycol and a soft segment component in the presence of a catalyst, followed by polycondensation of the resulting reaction product, and a method of esterifying a dicarboxylic acid with an excess amount of a glycol and a soft segment component in the presence of a catalyst, followed by polycondensation of the resulting reaction product.

[0037] [Polyolefin resin (B)] The polyolefin resin (B) is contained in an amount of 5 to 100 parts by mass per 100 parts by mass of the thermoplastic polyester block copolymer (A). The content of the polyolefin resin (B) is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, per 100 parts by mass of the thermoplastic polyester block copolymer (A). If the content of the polyolefin resin (B) is less than 5% by mass, the resulting thermoplastic polyester elastomer will not have sufficient low specific gravity and low dielectric properties, while if it is more than 100% by mass, the flexibility of the thermoplastic polyester elastomer will be impaired.

[0038] The polyolefin resin (B) used in the present invention is selected from a group of polyolefin resins having a flexural modulus of less than 2000 MPa measured in accordance with JIS K7171: 2022. The polyolefin resin (B) is preferably at least one selected from polyethylene resin (PE resin), polypropylene resin (PP resin), and olefin elastomer resin.

[0039] An example of a polyolefin resin (B) that can be effectively used in the present invention is polyethylene resin (PE resin). Examples of polyethylene resin (PE resin) include homopolyethylenes made with ethylene monomers, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), as well as copolymers of ethylene and α-olefins. Of these, high-density polyethylene (HDPE) is preferred. Examples of polypropylene resin (PP resin) include homopolypropylene, copolymers of ethylene and propylene, α-olefins, random block copolymers, and block copolymers of polypropylene.

[0040] Specific examples of the olefin-based resin include ethylene / propylene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene-butene-1 copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / butene-1 / maleic anhydride copolymer, ethylene / propylene / maleic anhydride copolymer, and ethylene / maleic anhydride copolymer.

[0041] Examples of polyolefin elastomers include copolymers containing copolymerized units of alpha-olefin monomer units selected from ethylene, 1-butene, 1-hexane, 1-octene, etc., which are C2 to C24 alpha-olefins, and which are composed of 50 mass% or more of ethylene and / or propylene. Preferably, the polyolefin elastomer has an ethylene content of 50 mass% to 80 mass%.

[0042] The polyolefin resin (B) that can be effectively used in the present invention has a flexural modulus of less than 2000 MPa and a resin density of 0.950 kg / m 3 It is preferable to select and use a material with a low specific gravity as the thermoplastic polyester elastomer composition, and the polyolefin resin (B) having a density of 0.950 kg / m or more can be preferably used. 3When the molecular weight is greater than 1000, not only is the dispersibility in the thermoplastic polyester block copolymer (A) excellent, but the flexibility and mechanical properties of the resulting thermoplastic polyester elastomer composition are also excellent, so this can be preferably selected.

[0043] The melt viscosity index (MFR) of the polyolefin resin (B) that can be effectively used in the present invention is preferably 5 to 100 g / 10 min, more preferably 10 to 75 g / 10 min, and even more preferably 15 to 50 g / 10 min, when measured at a temperature of 230° C. and a load of 2.16 kg according to ASTM D 1238. An MFR of less than 5 g / 10 min or more than 100 g / 10 min is undesirable because the difference in melt viscosity from the thermoplastic polyester block copolymer (A) causes the resin pressure of the extruded resin to become unstable during melt kneading.

[0044] The ratio [M(A) / M(B)] of the MFR (230°C / 2.16 kg) of the polyolefin resin (B) that can be effectively used in the present invention, [M(B)], to the MFR (230°C / 2.16 kg) of the thermoplastic polyester block copolymer (A), [M(A)], is preferably 0.1 to 4.0, more preferably 0.2 to 3.5, and even more preferably 0.2 to 3.0. If [M(A) / M(B)] is outside the range of 0.1 to 4.0, the difference in melt viscosity between the thermoplastic polyester block copolymer (A) and the polyolefin resin (B) will result in unstable resin pressure of the extruded resin during melt kneading, which is undesirable.

[0045] As the polyolefin resin (B) used in the present invention, not only conventional polyolefin resins derived from petroleum, which is a fossil fuel, but also biomass polyolefins, which are biomass plastics derived from plants, can be preferably used. More preferably, from the viewpoint of carbon neutrality, biomass polyethylene is used, which is obtained by using bioethanol derived from plant resources as a raw material and obtaining bioethylene as a raw material monomer.

[0046] In the polyolefin resin (B) used in the present invention, there is no significant difference between materials derived from fossil fuels and biomass materials derived from plant resources as long as they meet the above-mentioned properties. The difference between biomass-derived olefins (ethylene, propylene, α-olefins) and fossil fuel-derived olefins (ethylene, propylene, α-olefins) is as follows: 14 According to ASTM D6866, biomass-derived olefins contain 1 / 10 of the total carbon. 12 At a concentration of about 14 The biomass content can be estimated based on the presence of C. Therefore, both biomass-derived olefin materials and fossil fuel-derived olefin materials can be suitably used in thermoplastic polyester elastomer compositions. From the viewpoint of carbon neutrality in terms of environmental impact, the amount of biomass material in the thermoplastic polyester elastomer composition is preferably 25% by mass or more, calculated as a biomass raw material.Moreover, biomass polyolefins having a biomass content of 90% or more according to ASTM D6866 are even more preferred.

[0047] [Styrene-based block copolymer (C)] In the present invention, 5 to 50 parts by mass of a styrene-based block copolymer (C) having an aromatic vinyl unit content of 20 to 50% by mass is contained relative to 100 parts by mass of the thermoplastic polyester block copolymer (A). The content of the styrene-based block copolymer (C) is preferably 10 to 40% by mass, more preferably 10 to 30% by mass, relative to 100 parts by mass of the thermoplastic polyester block copolymer (A). If the content of the styrene-based block copolymer (C) is less than 5% by mass, the dispersibility of the polyolefin-based resin (B) in the resulting thermoplastic polyester elastomer deteriorates, resulting in a loss of flexibility of the thermoplastic polyester elastomer. If the content of the styrene-based block copolymer (C) is greater than 50% by mass, the thermoplastic polyester elastomer softens, resulting in a loss of durability and melt processing stability.

[0048] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, and pt-butylstyrene, with styrene being preferred. A thermoplastic styrene elastomer can be used as the styrene-based block copolymer (C) of the present invention. The hard segment is composed of a polystyrene block and a flexible elastomer block, and the block copolymer has multiple blocks, such as a diblock or triblock. Examples of thermoplastic styrene elastomers include styrene-ethylene-butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-ethylene-propylene-styrene (SEPS), polystyrene-poly(ethylene-ethylene / propylene) block-polystyrene (SEEPS), and styrene-isoprene-styrene (SIS).

[0049] The styrene block copolymer (C) is a modified styrene thermoplastic elastomer, and is preferably styrene-ethylene-butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-ethylene-propylene-styrene (SEPS), styrene-isoprene-styrene (SIS), or a combination of these block copolymers. Among these, styrene-ethylene-butylene-styrene (SEBS) is preferred from the viewpoint of dispersibility in the thermoplastic polyester block copolymer (A).

[0050] The content of styrene block units in SEBS is preferably 20% by mass to 40% by mass, more preferably 20% to 30% by mass. If the content of styrene block units is less than 20% by mass, this is not preferred from the viewpoint of maintaining the flexibility of the resulting thermoplastic polyester elastomer and suppressing molding shrinkage, while if the content of styrene block units is more than 50% by mass, this is not preferred because the flexibility of the thermoplastic polyester elastomer is impaired.

[0051] In the present invention, modified hydrogenated styrene block copolymers are preferably used, and acid-modified hydrogenated styrene elastomers and amine-modified styrene elastomers are particularly preferred. Modified hydrogenated styrene elastomers have molecular units containing carboxylic acid groups or derivative groups, amino groups, etc. bonded to them. Examples of such carboxylic acid groups or derivative groups include α,β-unsaturated carboxylic acids such as maleic acid and itaconic acid, and their dicarboxylic acid anhydrides, maleic anhydride, itaconic anhydride, etc., as well as imide compounds of α,β-unsaturated dicarboxylic acids such as N-phenylmaleimide, N-methylmaleimide, and Nt-butylmaleimide. Other examples include methyl methacrylate, glycidyl methacrylate, and amino groups. Among these, maleic anhydride and glycidyl methacrylate are preferred. The acid anhydride or glycidyl group reacts with the carboxyl end of the thermoplastic polyester block copolymer (A) to bond and interact during melt kneading, thereby improving the dispersibility of the styrene block copolymer (C) and the polyolefin resin (B) in the thermoplastic polyester block copolymer, thereby improving the low shrinkage, low dielectric constant, heat resistance, hydrolysis resistance, chemical resistance, blocking resistance, mold releasability, etc. of the thermoplastic polyester elastomer resin. Furthermore, since a decrease in melt tension can be suppressed, this contributes to discharge stability during melt processing and is preferred because it has an excellent balance of mechanical strength and flexibility.

[0052] In the case of a thermoplastic styrene elastomer that is not a modified hydrogenated styrene block copolymer, the weight-average molecular weight of the styrene block copolymer (C) is preferably 100,000 to 300,000, more preferably 200,000 to 300,000. Having the weight-average molecular weight of the styrene block copolymer (C) within the above range not only improves dispersibility in the thermoplastic polyester block copolymer (A) but also promotes compatibility between the thermoplastic polyester block copolymer (A) and the polyolefin resin (B) during melt-kneading with the polyolefin resin (B), and provides an effect of stabilizing the resin pressure of the extruded resin during melt-kneading.

[0053] If the weight-average molecular weight of the styrene-based block copolymer (C) is less than 100,000, the balance between mechanical strength and flexibility of the resulting thermoplastic polyester elastomer resin is deteriorated, which is undesirable.If the weight-average molecular weight is more than 300,000, the dispersibility in the thermoplastic polyester block copolymer (A) is deteriorated, which reduces processability during melt extrusion, which is undesirable.

[0054] [Polyamide copolymer (D)] The thermoplastic polyester elastomer resin composition of the present invention preferably contains a polyamide copolymer (D). The polyamide copolymer (D) used in the present invention is a polymeric compound having an amide bond in the molecular chain, and is preferably a copolymer of two or more different polycondensates of polyamide resins composed of a lactam polymer, a salt polymer obtained by reacting adipic acid, sebacic acid, or dodecanedioic acid with ethylenediamine, hexamethylenediamine, or metaxylenediamine, or a polymer of an ω-aminocarboxylic acid. Examples of the polyamide copolymer (D) in the present invention include copolymers such as polyamide 6 / polyamide 610, polyamide 6 / polyamide 610 / polyamide 12, polyamide 6 / polyamide 12, polyamide 6 / polyamide 66 / polyamide 12, and polyamide 6 / polyamide 66 / polyamide 610. The polyamide copolymer (D) exhibits even greater effects when it is a two or more component polyamide copolymer in which at least polyamide 6 and / or polyamide 610 is combined, and it is particularly preferred that it is a terpolymer of polyamide 6 / polyamide 66 / polyamide 610.

[0055] The amount of polyamide copolymer (D) blended is preferably 0.5 to 10 parts by mass, more preferably 1 to 7 parts by mass, and even more preferably 1.5 to 5 parts by mass, per 100 parts by mass of polyester block copolymer (A). If the amount of polyamide copolymer (D) blended is less than 0.5 parts by mass, the degree to which the desired improving effect is obtained is small, and if it exceeds 10 parts by mass, the flexibility and flex fatigue resistance inherent to the thermoplastic polyester elastomer resin composition are impaired, which is undesirable.

[0056] [Antioxidant (E)] The thermoplastic polyester elastomer composition of the present invention can further have improved heat resistance and stability during melt processing by adding an antioxidant (E).

[0057] The antioxidant (E) used in the present invention may be one selected from the group consisting of aromatic amine-based antioxidants, hindered phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants, or two or more of these may be used in combination.

[0058] Specific examples of aromatic amine antioxidants include phenylnaphthylamine, 4,4'-dimethoxydiphenylamine, bis[4-(1-phenyl-1-methylethyl)phenyl]amine, and 4-isopropoxydiphenylamine, and among these, the use of the diphenylamine compound bis[4-(1-phenyl-1-methylethyl)phenyl]amine is preferred.

[0059] Specific examples of hindered phenol antioxidants include pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), N,N'-hexane-1,6-diylbis(3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 3,3',3'',55'5''-hexa-tert-butyl-α,α',α''-(mesitylene-2,4,6-triyl)tri-p-cresol, and it is preferable to use a compound having a molecular weight of 500 or more.

[0060] The sulfur-based antioxidants are compounds containing sulfur, such as thioethers, dithioacid salts, mercaptobenzimidazoles, thiocarbanilides, and thiodipropionates. Among these, the use of didodecyl 3,3'-thiodipropionate, a thiodipropionate compound, is particularly preferred.

[0061] Phosphorus-based antioxidants are compounds containing phosphorus, such as phosphoric acid, phosphorous acid, hypophosphorous acid derivatives, phenylphosphonic acid, polyphosphonates, dialkyl pentaerythritol diphosphites, and dialkyl bisphenol A diphosphites. Among these, compounds containing both phosphorus and sulfur atoms in the molecule, or compounds containing two or more phosphorus atoms in the molecule, are preferred. Tris(2,4-di-tert-butylphenyl)phosphite is particularly preferred.

[0062] The total amount of these antioxidants (E) added is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the thermoplastic polyester elastomer.

[0063] [Weather resistance improver] To improve weather resistance, the thermoplastic polyester elastomer of this embodiment may optionally contain ultraviolet absorbers (UVA) and light stabilizers (HALS) as weather resistance improvers. Examples of ultraviolet absorbers include benzotriazoles such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole, and 2-[5-chloro-(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol, and benzophenones such as 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octoxybenzophenone. The amount of the ultraviolet absorbers added is preferably 0.1 to 2.0 parts by mass, more preferably 0.2 to 1.0 parts by mass, per 100 parts by mass of the thermoplastic polyester elastomer resin composition.

[0064] Examples of hindered amine compounds that serve as light stabilizers include the NR-type tertiary amine bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate and the N-OR-type amine 2,4-bis[N-butyl-N-(1-cyclohexyloyl-2,2,6,6-tetramethylpiperidic-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-tetrazine. The amount added is preferably 0.1 to 2.0 parts by mass, more preferably 0.2 to 1.0 parts by mass, per 100 parts by mass of the thermoplastic polyester elastomer resin composition.

[0065] [Other thermoplastic resins] The thermoplastic polyester elastomer resin of the present invention may be a thermoplastic resin other than the thermoplastic polyester block copolymer (A), such as a polyester resin other than the thermoplastic polyester elastomer resin of the present invention, an ethylene copolymer, a polyurethane resin, a polycarbonate resin, or an amorphous resin.

[0066] Specific examples of polyester resins other than the thermoplastic polyester elastomer resin of the present invention that can be preferably used include polybutylene terephthalate resin (PBT resin) and polyethylene terephthalate resin (PET resin).

[0067] Specific examples of ethylene copolymers include ethylene-vinyl acetate copolymer (PVA resin), ethylene-vinyl alcohol copolymer (EVOH resin), ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid ester copolymer. Polymethyl methacrylate (PMMA resin), which is a methyl methacrylate polymer, can be preferably used in combination. Also, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer (AS resin), and styrene polymer (PS resin) can be preferably used in combination.

[0068] Polycarbonate resins that can be effectively used in combination with the present invention include bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, as well as special polycarbonate resins produced using other dihydric phenols. For example, polycarbonate resins containing 4,4'-(m-phenylenediisopropylidene)diphenol or 1,1-bis(4-hydroxyphenyl)cyclohexane as part or all of the dihydric phenol component can also be preferably used in combination.

[0069] Examples of amorphous resins that can be effectively used in combination with the present invention include epoxy resins and phenoxy resins. Among these, examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, as well as glycidyl ether epoxy compounds which are polycondensates of phenol compounds and epichlorohydrin, phenol novolac epoxy resins, cresol novolac epoxy resins, and dicyclopentadiene epoxy resins. Phenoxy resins are polyhydroxy polyethers synthesized from bisphenols and epichlorohydrin, and examples include bisphenol A phenoxy resins and bisphenol F phenoxy resins which have hydroxyl terminal groups.

[0070] The thermoplastic resins other than the thermoplastic polyester elastomer can be used for the purposes of adjusting melt processability and flowability, improving the dispersibility and compatibility of various additives, adjusting flexibility and elastic modulus, improving heat resistance and heat aging resistance, and improving chemical resistance.

[0071] The blending amount of the thermoplastic resin other than the thermoplastic polyester elastomer is preferably 1 to 20 parts by mass, more preferably 5 to 10 parts by mass, per 100 parts by mass of the polyester block copolymer (A). If the blending amount is less than 1 part by mass, the combined effect of the thermoplastic resin used in combination is limited, while if the blending amount exceeds 20 parts by mass, the dispersibility of the other thermoplastic resin in the thermoplastic polyester elastomer decreases, impairing the flexibility, mechanical properties, moldability, etc., inherent to the thermoplastic polyester elastomer resin composition of the present invention, and therefore is not preferred.

[0072] [Fiber reinforcement] The thermoplastic polyester elastomer resin composition of the present invention may contain a fiber reinforcing material within a range that does not impair flexibility. By incorporating a fiber reinforcing material, mechanical strength and heat resistance can be further improved.

[0073] Examples of fiber reinforcement include glass fiber, aramid fiber, carbon fiber, cellulose nanofiber, alumina fiber, and silicon carbide fiber, with glass fiber and aramid fiber being preferred. Chopped strand and roving glass fibers are preferred as glass fibers. Glass fibers treated with a sizing agent containing a silane coupling agent such as an aminosilane compound or an epoxysilane compound and / or urethane, a copolymer of acrylic acid such as an acrylic acid / styrene copolymer, a copolymer of maleic anhydride such as a methyl acrylate / methyl methacrylate / maleic anhydride copolymer, vinyl acetate, bisphenol A diglycidyl ether, or one or more epoxy compounds such as a novolac epoxy compound can also be used. Glass fibers treated with a sizing agent containing a copolymer of maleic anhydride are preferred because they can further improve heat resistance. The fiber diameter of the fiber reinforcement is preferably in the range of 1 to 30 μm. From the viewpoint of dispersibility of the fiber reinforcement in the resin, the lower limit is preferably 5 μm. From the viewpoint of mechanical strength, the upper limit is preferably 15 μm. Although the fiber cross section is usually circular, fiber reinforcing materials with any cross section, such as oval glass fibers with any aspect ratio, flat glass fibers, and cocoon-shaped (HIS) glass fibers, can also be used, which has the effect of improving flowability during injection molding and producing molded products with less warpage. The shrinkage characteristics of molded products that occur when these fiber reinforcing materials are used in combination can be reduced in the thermoplastic polyester elastomer resin composition of the present invention.

[0074] The thermoplastic polyester elastomer resin composition of the present invention may contain a reinforcing material other than a fiber reinforcing material within a range that does not impair flexibility. By blending a reinforcing material other than a fiber reinforcing material, the crystallization characteristics of the molded article can be improved, and some of the properties of the molded article, such as anisotropy, heat resistance, heat distortion temperature, mechanical strength, and flame retardancy, can be improved.

[0075] [Other additives] Furthermore, the thermoplastic polyester elastomer resin composition of the present invention can contain the following known additives as needed, provided that the intended purpose is not impaired. Antioxidants other than those listed as antioxidant (E) may also be used as thermal stabilizers during melt processing. Examples of antistatic agents include polyether ester amide, flake graphite, granular graphite, granular conductive acetylene carbon black, conductive hollow carbon Ketjenblack, multi-layer graphene, and multi-wall carbon nanotubes. The amount of antistatic agent added is preferably 0.1 to 5.0 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the thermoplastic polyester elastomer resin composition.

[0076] Examples of lubricants include stearyl alcohol, metal stearates, stearic acid amides, and glycerides of stearic acid. Examples of release agents include polyolefin waxes (which do not fall under the olefin resins described in this invention), paraffin waxes, saturated fatty acid esters, unsaturated fatty acid esters, and aliphatic amide compounds.

[0077] Organic dyes such as nigrosine, various colorants, carbon black, titanium dioxide, etc. as pigments, and phthalates, adipates, trimellitates, etc. as plasticizers may also be used.

[0078] To further improve the durability of the thermoplastic polyester elastomer resin composition, a carbodiimide compound, a polycarbodiimide compound, an epoxy compound, an epoxy resin, or the like may be blended as a hydrolysis resistance improver. Furthermore, to improve flame retardancy, flame retardants such as aluminum phosphinate, zinc phosphinate, melamine cyanurate, a triazine ring-containing N-alkoxy hindered amine compound, and organic condensed phosphate esters may be used in combination with bromine atom-substituted halogen-based flame retardants such as brominated polycarbonate, brominated polystyrene, and brominated polyacrylate, and further, highly active metal compounds such as antimony trioxide, zinc sulfide, zinc borate, and zinc stannate may be used as auxiliary agents for these. Furthermore, additives such as an ester exchange inhibitor may also be blended.

[0079] [Molded body] The thermoplastic polyester elastomer resin composition of the present invention can be made into a polyester elastomer molded article using a commonly used molding machine such as injection molding, blow molding, extrusion molding, compression molding, extrusion film formation, T-die film formation, calendar film formation, etc. The shape of the polyester elastomer molded article is not particularly limited and can be selected depending on the molding method, etc., and may be any of one-dimensional (e.g., linear, rod-like, etc.), two-dimensional (e.g., sheet-like, frame-like, film-like, etc.), and three-dimensional (e.g., a shape having recesses, protrusions, or uneven portions, a tube-like, a hose-like, etc.).

[0080] The thermoplastic polyester elastomer resin composition of the present invention can also be used as a composite molded article by insert molding, hybrid molding, two-color molding, etc. The composite molded article made of the thermoplastic polyester elastomer resin composition of the present invention may contain other resin materials.

[0081] The uses of the thermoplastic polyester elastomer molded article are not particularly limited, but include, for example, various housings, cover materials, connector parts, communication device parts, automotive electrical parts, automotive interior / exterior parts, electric wire applications, precision instruments, etc. in the electrical and electronic fields, taking advantage of its low dielectric properties, and it can be suitably used for extrusion processed products such as tube parts, hose parts, multilayer tubes, etc., taking advantage of its good processability. Furthermore, in addition to general consumer goods and their parts, it can also be suitably used for films, sheets, fibers, and their advanced processed products such as cushioning materials, woven and knitted fabrics, laminate applications, and adhesive layers between various materials. [Example]

[0082] The effects of the present invention will be explained by the following examples. The present invention can be practiced with appropriate modifications within the scope of the gist of the invention. Note that, unless otherwise specified, all % and part notations in the examples are based on mass. Furthermore, the physical properties shown in the examples were measured by the following measurement methods.

[0083] In the examples and comparative examples, the properties obtained by the thermoplastic polyester elastomer resin compositions were evaluated by the measurement methods described below.

[0084] [Test piece molding] Using an injection molding machine NEX1000 manufactured by Nissei Plastic Industrial Co., Ltd., the polyester elastomer resin composition of the present invention was injection molded at a molding temperature of 200°C when the melting point of the polyester block copolymer (A) was less than 180°C, or at a molding temperature 20°C higher than the melting point of the polyester block copolymer (A) for compositions in which the melting point of the polyester block copolymer (A) exceeded 180°C, at a mold temperature of 40°C, with a molding cycle consisting of a 10-second total injection time and dwell time and a 15-second cooling time, to obtain JIS No. 2 test pieces (rod-shaped test pieces) and 125 mm x 75 mm x 2 mm thick square plates.

[0085] [specific gravity] The 125mm x 75mm x 2mm thick square plate prepared by the above molding method was cut into a sample with dimensions of 10 x 10mm, and the specific gravity was measured at 23°C and 50% RH using a dry density meter Accupyc II1345 manufactured by Shimadzu Corporation in accordance with JIS Z8807:2012.

[0086] [Surface hardness (HDD: hardness measured by Durometer D)] According to the method described in JIS K7215:1986 (ISO 868), the surface hardness D of the molded body was measured in a temperature-controlled environment of 23°C and 50% RH.

[0087] [Tensile elongation at break (%)] Using the JIS No. 2 test piece prepared by the above molding method, the tensile elongation at break (%) was measured in accordance with JIS K7161:2014. The pulling speed was 200 mm / min. The tensile elongation at break obtained varies depending on the type of polyester block copolymer (A) used, but it is preferable that the tensile elongation at break of the polyester elastomer resin composition obtained in the state where the JIS No. 2 test piece was molded is 100% or more.

[0088] [Hydrolysis resistance] Using JIS No. 2 test pieces prepared by the above molding method, they were subjected to continuous exposure for 150 hours using an EHS-212M highly accelerated life testing machine manufactured by Espec Corporation under conditions conforming to JIS C60068-2-66:2001, namely, a temperature of 121°C and a relative humidity of 100% (unsaturation control). After this, the tensile elongation at break (%) was measured according to JIS K7161:2014 and used as an index of hydrolysis resistance. The tensile elongation at break obtained varies depending on the type of polyester block copolymer (A) used, but from the viewpoint of durability and toughness retention in use under high-temperature, humid heat environments, it is preferable that the tensile elongation at break be 100% or more even after the above-mentioned high-temperature, humid heat treatment.

[0089] [Mold shrinkage rate] The mold shrinkage of the thermoplastic elastomer resin composition of this example was evaluated using a 125mm x 75mm x 2mm square plate prepared using the molding method described above. As with the method described above, molding was performed under the following conditions: cylinder temperature 200°C, mold temperature 40°C, and cooling time 30 seconds. The holding pressure was set to either 20MPa or 40MPa, depending on which pressure resulted in the least warpage and sink marks on the molded square plate after release. The dimension (L) of the 2mm-thick square plate released from the mold by the ejector was measured using a measuring instrument. The difference between the square plate dimension (L) and the mold dimension (Lc) (shrinkage: Lc - L) was calculated by dividing the difference by the mold dimension (Lc).

[0090] Of these, the shrinkage rate (%) in the direction of resin flow (MD direction) from the mold gate (a square plate film gate or a fan gate can be selected) toward the cavity was defined as MD (%), and the shrinkage rate (%) in the direction perpendicular to the direction of resin flow (TD direction) was defined as TD (%), and these were used as evaluation indices for molding shrinkage rate.

[0091] [Dielectric constant, dielectric loss tangent] Using a 125mm x 75mm x 2mm thick square plate prepared using the above molding method, the relative permittivity and dielectric loss tangent at a frequency of 1MHz were measured using an Agilent Technologies Precision LCR Meter E4980A in an environment of 23°C and 50% RH in accordance with the test method IEC62631-2-1 (automatic balancing bridge method).

[0092] In addition, a 125mm x 75mm x 2mm thick square plate prepared using the above molding method was cut to 80mm x 1.5mm x 1.5mm, and the dielectric constant and dielectric loss tangent at a frequency of 10GHz were measured in accordance with the test method IEC62810 (cavity resonator perturbation method) at 23°C and 50% RH using a 9PNA network analyzer N5222B manufactured by Keysight Technologies and a 10GHz cavity resonator CP531 manufactured by Kanto Electronics Application Development.

[0093] The dielectric constant at a frequency of 1 MHz is preferably 3.3 or less, more preferably 3.0 or less. Also, the dielectric constant at a frequency of 10 GHz is preferably 3.0 or less, more preferably 2.5 or less. By having the dielectric constant values ​​at frequencies of 1 MHz and 10 GHz that are equal to or less than the aforementioned values, the material has the properties required for electronic material applications as a low dielectric constant and low loss material.

[0094] [Observation of the dispersed morphology of thermoplastic polyester elastomer composition] The extruded pellets obtained after melt kneading in the examples were cut using an ultramicrotome to prepare ultrathin sections. The prepared ultrathin sections were stained and morphologically observed at 5000x magnification using a Hitachi High-Tech H-7650 transmission electron microscope (TEM). The thermoplastic polyester block copolymer (A) was used as a matrix, and the polyolefin resin (B) was observed to be dispersed as domains via the styrene block copolymer (C). As shown in Figure 1, thermoplastic polyester elastomer compositions that exhibited the morphology of the dispersion were marked with an ◯, and thermoplastic polyester elastomer compositions that exhibited a morphology other than the dispersion were marked with an X.

[0095] In morphology observation at 5000x magnification using a transmission electron microscope (TEM), the thermoplastic polyester block copolymer (A) is preferably a matrix, with the polyolefin resin (B) dispersed as domains via the styrene-based block copolymer (C). Dispersing the polyolefin resin (B) in the thermoplastic polyester block copolymer (A) via the styrene-based block copolymer (C) improves the wettability and interaction of the polyolefin resin (B) with the thermoplastic polyester block copolymer (A), suppressing a decrease in toughness when stress changes occur in the polyester elastomer resin composition of the present invention, and further improving hydrolysis resistance. Furthermore, a smaller dispersion diameter of the polyolefin resin (B) in the thermoplastic polyester block copolymer (A) is preferred, as it results in a lower dielectric constant and lower loss.

[0096] [Method for producing thermoplastic polyester block copolymer (A1)] A thermoplastic polyester block copolymer (A1) was produced, whose constituent components were 60% by mass of hard segments (H) composed of crystalline aromatic polyester units and 40% by mass of soft segments (L) composed of aliphatic polyether units, in which the hard segments (H) were composed of a dicarboxylic acid component and a diol component.

[0097] 50.5 parts by weight of terephthalic acid, 42.4 parts by weight of 1,4-butanediol, and 35.4 parts by weight of poly(tetramethylene oxide) glycol with a number-average molecular weight of approximately 1400 were charged into a reaction vessel equipped with a helical ribbon stirrer, along with 0.04 parts by weight of titanium tetrabutoxide and 0.02 parts by weight of mono-n-butyl-monohydroxytin oxide. The mixture was heated at 190-225°C for 3 hours, and the esterification reaction was carried out while the reaction water was drained out of the system. 0.2 parts by weight of tetra-n-butyl titanate was added to the reaction mixture, and 0.05 parts by weight of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy Corporation) was added. The mixture was then heated to 245°C, and the pressure in the system was reduced to 27 Pa over 50 minutes. Polymerization was carried out under these conditions for 2 hours and 50 minutes. The resulting polymer was extruded into water in the form of strands and cut into pellets. The melting point of the thermoplastic polyester block copolymer (A1) thus obtained was 207° C. The MFR measured at 230° C. and 2.16 kg was 44 g / 10 min.

[0098] [Method for producing thermoplastic polyester block copolymer (A2)] A thermoplastic polyester block copolymer (A2) was produced, whose constituent components were 50% by mass of a hard segment (H) composed of a crystalline aromatic polyester unit and 50% by mass of a soft segment (L) composed of an aliphatic polyether unit, in which the hard segment (H) was composed of two types of dicarboxylic acid components and a diol component.

[0099] 33.0 parts by weight of terephthalic acid, 9.7 parts by weight of isophthalic acid, 40.3 parts by weight of 1,4-butanediol, and 46.5 parts by weight of poly(tetramethylene oxide) glycol with a number average molecular weight of approximately 1400, together with 0.04 parts by weight of titanium tetrabutoxide and 0.02 parts by weight of mono-n-butyl-monohydroxytin oxide, were charged into a reaction vessel equipped with a helical ribbon stirrer, heated at 190 to 220 °C for 3 hours, and the esterification reaction was carried out while the reaction water was discharged out of the system. 0.15 parts by weight of tetra-n-butyl titanate was added to the reaction mixture, and 0.05 parts by weight of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy) was added. The temperature was then raised to 245 °C, and the pressure in the system was reduced to 27 Pa over 50 minutes. Polymerization was carried out under these conditions for 2 hours and 40 minutes. The resulting polymer was extruded into water in the form of a strand and cut into pellets. The melting point of the resulting thermoplastic polyester block copolymer (A2) was 158° C. The MFR measured at 230° C. and 2.16 kg was 22 g / 10 min.

[0100] [Method for producing thermoplastic polyester block copolymer (A3)] A thermoplastic polyester block copolymer (A3) was produced, whose constituent components were 25% by mass of hard segments (H) composed of crystalline aromatic polyester units and 75% by mass of soft segments (L) composed of aliphatic polyether units, in which the hard segments (H) were composed of a dicarboxylic acid component and a diol component.

[0101] 27.0 parts by mass of terephthalic acid, 23.4 parts by mass of 1,4-butanediol, 0.01 parts by mass of tetrabutyl titanate, and 0.01 parts by mass of mono-n-butyl-monohydroxytin oxide were charged into an esterification vessel equipped with a rectification column and a stirrer, and the esterification reaction was initiated at 160°C under a reduced pressure of 700 mmHg. The temperature was then gradually increased, and an additional 5.9 parts by mass of 1,4-butanediol was continuously added. A transparent reaction product was obtained 3 hours and 40 minutes after the start of the reaction, and the reaction was terminated. After the esterification reaction was completed, 0.18 parts by mass of tetrabutyl titanate as a polycondensation catalyst and 0.1 parts by mass of "IRGANOX" 1330 (a hindered phenol antioxidant manufactured by BASF) as a stabilizer were added to the esterification tank. Meanwhile, 68.6 parts by mass of poly(tetramethylene oxide) glycol with a number-average molecular weight of 1400 was added to the polycondensation tank, and the esterification reaction product was transferred from the esterification tank to the polycondensation tank. The reaction system in the polycondensation tank was stirred and polymerized while gradually reducing pressure from atmospheric pressure to a high vacuum of 1 mmHg or less over 1 hour. At the same time, the temperature was raised to 245°C, and polycondensation was carried out for 3 hours and 30 minutes under conditions of 245°C and 1 mmHg or less. The resulting polymer was extruded into water in the form of strands and cut into pellets. The melting point of the resulting thermoplastic polyester block copolymer (A3) was 162°C. The MFR measured at 230°C and 2.16 kg was 30 g / 10 min.

[0102] [Method for producing thermoplastic polyester block copolymer (A4)] A thermoplastic polyester block copolymer (A4) was produced, whose constituent components were 80% by mass of hard segments (H) composed of crystalline aromatic polyester units and 20% by mass of soft segments (L) composed of aliphatic polyether units, in which the hard segments (H) were composed of a dicarboxylic acid component and a diol component.

[0103] 575 parts by weight of terephthalic acid, 484 parts by weight of 1,4-butanediol, and 149 parts by weight of poly(oxytetramethylene) glycol with a number-average molecular weight of approximately 1,000 were charged into a reaction vessel equipped with a helical ribbon stirrer, along with 0.3 parts by weight of titanium tetrabutoxide and 0.2 parts by weight of mono-n-butyl-monohydroxytin oxide. The mixture was heated at 190-225°C for 3 hours, and the esterification reaction was carried out while the reaction water was drained out of the system. 1.5 parts by weight of tetra-n-butyl titanate was added to the reaction mixture, and 0.5 parts by weight of "Irganox" 1098 (a hindered phenol-based antioxidant manufactured by Ciba-Geigy) was added. The mixture was then heated to 245°C, and the pressure in the system was reduced to 27 Pa over 50 minutes. Polymerization was carried out under these conditions for 1 hour and 50 minutes. The resulting polymer was extruded into water in the form of strands and cut into pellets. The obtained pellets were placed in a rotatable reaction vessel, the pressure in the system was reduced to 27 Pa, and the vessel was heated to 170 to 180°C for 20 hours while rotating to carry out solid-state polycondensation. The melting point of the resulting thermoplastic polyester block copolymer (A4) was 216°C. The MFR measured at 230°C and 2.16 kg was 9 g / 10 min.

[0104] [Thermoplastic polyester (A'5)] The thermoplastic polyester (A'5) was not a thermoplastic polyester block copolymer (A), but a polybutylene terephthalate resin, "Treycon" 1100S, manufactured by Toray Industries, Inc. The MFR measured at 230°C and 2.16 kg was 19 g / 10 min.

[0105] [Polyolefin resin (B)] As the polyolefin resin (B) having a flexural modulus of less than 2000 MPa, the following product groups were used. (B1) As a polyethylene resin, the flexural modulus is 1350 MPa and the density is 0.955 kg / m 3 The biomass PE resin SHA7260 (HDPE) manufactured by Braskem SA, which has a biomass content of 94%, was used. The MFR measured at 230°C and 2.16 kg was 35 g / 10 min. (B2) As a polyethylene resin, the flexural modulus is 1350 MPa and the density is 0.959 kg / m 3 The biomass PE resin SHC7260 (HDPE) with a biomass content of 94% manufactured by Braskem SA was used. The MFR measured at 230°C and 2.16 kg was 12 g / 10 min. (B3) As a polyethylene resin, the flexural modulus is 670 MPa and the density is 0.945 kg / m 3 The polymer used was "Ultzex" 4570 (LLDPE) manufactured by Prime Polymer Co., Ltd. The MFR measured at 230°C and 2.16 kg was 14 g / 10 min. (B4) Polypropylene resin with a flexural modulus of 1250 MPa and a density of 0.910 kg / m 3 The polymer used was "Prime Polypro" J715M manufactured by Prime Polymer Co., Ltd. The MFR measured at 230°C and 2.16 kg was 8 g / 10 min.

[0106] [Styrene-based block copolymer (C)] (C1) As the maleic anhydride modified hydrogenated styrene elastomer (SEBS), Asahi Kasei Corporation's "Tuftec" M1913, with a styrene / ethylene-butylene ratio of 29 / 71, was used. (C2) As the hydrogenated styrene elastomer (SEBS), Asahi Kasei Corporation's "Tuftec" H1272, which has a styrene / ethylene-butylene ratio of 35 / 65, was used. (C3) As the amine-modified hydrogenated styrene elastomer (SEBS), Asahi Kasei Corporation's "Tuftec" MP10, which has a styrene / ethylene-butylene ratio of 32 / 68, was used.

[0107] [Polyamide copolymer (D)] As the polyamide copolymer (D), the following product groups were used. (D1) "Amilan" CM4000 (a ternary copolymer of polycaprolactam, polyhexamethylene adipamide, and polyhexamethylene sebacamide) manufactured by Toray Industries, Inc. was used.

[0108] [Antioxidant (E)] As the antioxidant (E), the following product groups were used. (E1) Bis[4-(1-phenyl-1-methylethyl)phenyl]amine, an aromatic secondary amine, was used.

[0109] [Examples 1 to 10], [Comparative Examples 1 to 5] The thermoplastic polyester elastomer resin compositions in the examples and comparative examples were dry-blended in the ratios shown in Tables 1 and 2, and melt-kneaded using a twin-screw extruder with a 45 mmφ triple-start screw. The cylinder temperature was set to 200°C for thermoplastic polyester block copolymers with a melting point of 180°C or less, or to the melting point of the thermoplastic polyester block copolymer + 20°C for thermoplastic polyester block copolymers with a melting point of more than 180°C. The mixture was then extruded in the form of strands and subsequently pelletized into pellets of φ3 mm and length 3 mm using a pelletizer.

[0110] The resulting thermoplastic polyester elastomer composition pellets were dried at 90°C for 4 hours and then molded into JIS No. 2 test pieces and 125mm x 75mm x 2mm thick square plates using an injection molding machine (NEX-1000) manufactured by Nissei Plastic Industrial Co., Ltd. The molded test pieces were evaluated for the following evaluation parameters: specific gravity, surface hardness, tensile properties, tensile modulus, mold shrinkage (MD and TD), and dielectric constant and dielectric loss tangent (tanδ) at 1MHz and 10GHz. The evaluation results for each level are shown in Tables 1 and 2.

[0111] [Table 1]

[0112] [Table 2]

[0113] From the above, it is clear from the examples and comparative examples that the thermoplastic elastomer resin compositions of the present invention, which are prepared by blending the thermoplastic polyester block copolymer (A) shown in Examples 1 to 10 with the specific polyolefin resin (B) and the specific styrene block copolymer (C), can be imparted with low specific gravity, low shrinkage, and low dielectric constant properties while maintaining the excellent flexibility of a thermoplastic polyester elastomer, and also have excellent hydrolysis resistance. On the other hand, the polyester elastomer molded articles shown in the comparative examples do not satisfy all of these properties.

[0114] In comparison between Examples 1, 4, and 5 and Comparative Examples 1, 2, and 3, by blending a thermoplastic polyester block copolymer (A), a specific polyolefin resin (B), and a specific styrene block copolymer (C) in a specific blending ratio, a thermoplastic polyester elastomer resin composition having an excellent balance of flexibility, low specific gravity, and low shrinkage, favorable relative dielectric constant characteristics, and high hydrolysis resistance can be obtained.

[0115] In Examples 1 and 10 and Comparative Example 4, a thermoplastic polyester block copolymer (A), a specific polyolefin resin (B), and a specific styrene block copolymer (C) were blended in specific blending ratios to obtain a thermoplastic polyester elastomer resin composition that exhibits low specific gravity, low shrinkage, and low dielectric constant, while also achieving excellent flexibility and high hydrolysis resistance.

[0116] In comparison between Examples 1, 4, and 5 and Comparative Example 5, by using a specific thermoplastic polyester block copolymer (A) to prepare a thermoplastic polyester elastomer resin composition, it is possible to obtain a thermoplastic polyester elastomer resin composition that has an excellent balance of flexibility, low specific gravity, and low shrinkage, as well as high hydrolysis resistance.

[0117] When the thermoplastic polyester block copolymer (A) and the styrene block copolymer (C) are used without using the specific polyolefin resin (B) as in Comparative Examples 1 and 3, the molded article obtained from the thermoplastic elastomer resin composition is not preferable because the specific gravity and the relative dielectric constant increase.

[0118] Furthermore, when the thermoplastic polyester block copolymer (A) and the polyolefin resin (B) are used without using the specific styrene block copolymer (C) as in Comparative Example 2, the dispersibility of the polyolefin resin (B) is poor, resulting in poor flexibility of the thermoplastic polyester elastomer resin composition and failure to obtain a desirable specific gravity and dielectric constant, which is not preferred.

[0119] Furthermore, when the thermoplastic polyester block copolymer (A), the polyolefin resin (B), and the styrene block copolymer (C) are blended in a blending ratio different from that of the present invention, as in Comparative Example 4, the specific gravity and dielectric constant decrease, while the processability and flexibility become poor, and furthermore, the hydrolysis resistance also becomes poor, which is undesirable. [Industrial Applicability]

[0120] According to the present invention, it is possible to provide a thermoplastic polyester elastomer resin composition having a low specific gravity, low shrinkage, and low dielectric properties, and the composition can be suitably used in applications such as electrical and electronic equipment parts, automotive electrical parts, and industrial materials, which require a combination of the flexibility and impact resistance of polyester elastomers with the aforementioned low specific gravity, low shrinkage, and particularly low dielectric properties. [Explanation of symbols]

[0121] 1. Thermoplastic polyester block copolymer (A) 2 Polyolefin resin (B) 3. Styrenic block copolymer (C)

Claims

1. The thermoplastic polyester elastomer resin composition contains a thermoplastic polyester block copolymer (A) comprising, as its constituent components, 20 to 85% by mass of hard segments (H) whose main constituent units are crystalline aromatic polyester units and 15 to 80% by mass of soft segments (L) whose main constituent units are aliphatic polyether units and / or aliphatic polyester units; a polyolefin resin (B) having a flexural modulus of less than 2000 MPa as measured in accordance with JIS K7171:2022; and a styrene block copolymer (C) having an aromatic vinyl unit content of 20 to 50% by mass, wherein the thermoplastic polyester elastomer resin composition contains 5 to 100 parts by mass of the polyolefin resin (B) and 5 to 50 parts by mass of the styrene block copolymer (C) per 100 parts by mass of the thermoplastic polyester block copolymer (A).

2. 2. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the polyolefin resin (B) is at least one selected from the group consisting of polyethylene resin, polypropylene resin, and olefin elastomer resin.

3. 2. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the styrene-based block copolymer (C) is a modified styrene-based thermoplastic elastomer, which is styrene-ethylene-butylene-styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-ethylene-propylene-styrene (SEPS), styrene-isoprene-styrene (SIS), or a combination of these block copolymers.

4. 2. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the thermoplastic polyester elastomer resin composition contains 0.5 to 10 parts by mass of a polyamide copolymer (D) relative to 100 parts by mass of the thermoplastic polyester block copolymer (A), and the polyamide copolymer (D) is a two or more component polyamide copolymer in which at least polyamide 6 and / or polyamide 610 is combined.

5. 2. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the dielectric constant at a frequency of 1 MHz is measured in accordance with IEC 62631-2-1 test method using a 125 mm x 75 mm x 2 mm thick square plate molded in accordance with JIS K7152:1999 at 23°C and 50% RH, and the dielectric constant at a frequency of 10 GHz is measured in accordance with IEC 62810 test method using a 125 mm x 75 mm x 2 mm thick square plate cut to 80 mm x 1.5 mm x 1.5 mm.

6. The thermoplastic polyester elastomer resin composition according to claim 1, characterized in that the tensile elongation at break measured in accordance with JIS K7161:2014 using a JIS No. 2 test piece after continuous exposure for 150 hours at a temperature of 121°C and a relative humidity of 100% RH in accordance with JIS C60068-2-66:2001 is 100% or more.

7. 2. The thermoplastic polyester elastomer composition according to claim 1, wherein, in morphology observed at 5000 magnification using a transmission electron microscope (TEM), the thermoplastic polyester block copolymer (A) forms a matrix, and the polyolefin resin (B) is dispersed as domains via the styrene block copolymer (C).

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