JP6358368B1 - Thermoplastic polyester elastomer resin composition and foamed molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic polyester elastomer resin composition for foam molding suitable for molding a polyester elastomer foam molded body that is lightweight and exhibits high rebound resilience, and has a uniform foamed state despite a high foaming ratio. A polyester elastomer foam-molded article having a uniform foam cell structure using
SOLUTION: At least one selected from a hard segment composed of a polyester comprising an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol as constituent components, an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate. Of the soft segment, and 100 parts by mass of the thermoplastic polyester elastomer (A) having a soft segment content of 45 to 90% by mass, 0.1 to 4.5 parts by mass of the thickener (B). It is the polyester elastomer resin composition contained in a proportion. Furthermore, the density is 0.01 to 0.35 g / cm ^{3 made} of the resin composition, and the foamed molded product has a rebound resilience of 60 to 90%.
[Selection figure] None

Description

  The present invention relates to a thermoplastic polyester elastomer composition having high flexibility and excellent mechanical properties, and a foamed molded product thereof. More specifically, it is a thermoplastic polyester elastomer composition excellent in foam moldability, and the foam molded product obtained from the thermoplastic polyester elastomer composition of the present invention has a light weight and a high rebound resilience, and is easy to mold. It is possible to provide a high-quality foam molded article by this method.

  Thermoplastic polyester elastomers have excellent injection moldability and extrusion moldability, high mechanical strength, rubber properties such as elastic recovery, impact resistance, flexibility, and cold resistance. It is used for applications such as electronic parts, textiles, films and sports parts.

  Thermoplastic polyester elastomers are excellent in heat aging resistance, light resistance, and wear resistance, and are therefore used in automobile parts, particularly parts used in high temperature environments and automobile interior parts. In recent years, the weight of resin parts has been reduced, and one of the means for achieving the purpose is the application of foam molded products.

  However, since the polyester elastomer generally produced by the melt polycondensation method has a relatively low melt viscosity, when applied to a molding method that requires a high melt viscosity such as foam molding, blow molding, extrusion molding, etc., moldability The problem that cannot be secured occurs. Therefore, the polymer manufactured by the melt polycondensation method is increased to a melt viscosity applicable to blow molding or extrusion molding by blending a crosslinking agent or a thickener (for example, Patent Document 1, 2, 3).

  According to the above method, a polyester elastomer having a high melt viscosity can be obtained. However, since the reaction of the obtained polyester elastomer is not sufficiently controlled, the dependence of the melt viscosity on the residence time is large. In particular, when preparing a foamed molded article, the composition obtained by the above method is easily gelled depending on the conditions, and when sufficient melt tension is obtained, it tends to gel, and it is difficult to obtain stable fluidity. It is difficult to obtain a molded product with a thickness. Furthermore, although all the cited references mention the effect of thickening, details on the method for efficiently producing a foam molded article and the polyester elastomer composition suitable for the preparation of the foam molded article are detailed. Not mentioned.

  In Patent Document 4, a high-quality foam molded article is manufactured by controlling the melt tension of the polyester elastomer composition and suppressing the gel. However, the density of the foamed molded product is high, and production of a low-density foam that is satisfactory as a weight reduction has not been achieved. Furthermore, no consideration is given to cushioning and resilience required for foamed molded products.

  By the way, as a foam suitably used for an automobile seat, a highly repulsive urethane foam having a rebound resilience of 60% or more is suitably employed, and Patent Document 5 proposes a manufacturing method thereof. However, urethane foam has a problem of environmental pollution because cyanide gas and the like are generated during combustion.

JP-A-11-323110 JP-A-5-302022 JP 2009-29895 A JP 2012-140532 A JP 2003-342343 A

  The present invention has been made in view of the current state of the prior art described above, and an object of the present invention is to provide a thermoplastic polyester elastomer resin composition for foam molding that is lightweight and excellent in impact resilience, and a foam molded article comprising the same. There is.

  In order to achieve the above object, the present inventor diligently studied the composition of the thermoplastic polyester elastomer and the thickener. As a result, by using the thermoplastic polyester elastomer resin composition adjusted to a specific melt viscosity by blending a specific ratio of the hard segment and the soft segment of the thermoplastic polyester elastomer and a thickener, it is favorable. The present inventors have found that a foamed resin can be obtained that exhibits foam moldability, can be reduced in weight by high-magnification foaming, and has a very high rebound resilience. Furthermore, it has been found that a high-quality polyester elastomer foam molded article can be easily produced and provided by applying a process in which the mold is filled with a resin by injection molding and the cavity is expanded by the core back of the mold. Completed.

That is, according to the present invention, [1] to [10] are configured.
[1] A hard segment composed of a polyester comprising an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol as constituent components, and at least one selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate The proportion of the thickener (B) 0.1 to 4.5 parts by mass with respect to 100 parts by mass of the thermoplastic polyester elastomer (A) in which the soft segments are combined and the soft segment content is 45 to 90% by mass. A thermoplastic polyester elastomer resin composition for foam molding, comprising:
[2] The thickener (B) contains two or more glycidyl groups per molecule, has a weight average molecular weight of 4000 to 25000, and (X) 20 to 99% by mass of a vinyl aromatic monomer, (Y) It is a copolymer comprising 1 to 80% by mass of glycidyl (meth) acrylate and (Z) 0 to 79% by mass of a vinyl group-containing monomer other than (X) which does not contain an epoxy group. The thermoplastic polyester elastomer resin composition for foam molding according to [1].
[3] The antioxidant further includes at least one antioxidant selected from an aromatic amine-based antioxidant, a hindered phenol-based antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant. The thermoplastic polyester elastomer resin composition for foam molding according to [1] or [2], wherein the agent is contained at a ratio of 0.01 to 3 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer (A).
[4] The thermoplastic polyester elastomer resin composition for foam molding according to any one of [1] to [3], wherein the MFR at 230 ° C. is 10 to 20 g / 10 min.
[5] The density is 0.01 to 0.35 g / cm ³ made of the thermoplastic polyester elastomer resin composition according to any one of [1] to [4], and the rebound resilience is 60 to 90%. A foamed molded product characterized by being:
[6] The foamed molded article according to [5], wherein the impact resilience is 70% to 90%.
[7] The foam molded article according to [5] or [6], wherein the density is 0.01 to 0.25 g / cm ³ .
[8] The surface layer has a non-foamed skin layer having a thickness of 100 to 800 μm, the inner layer has a foamed layer composed of foamed cells having an average cell diameter of 10 to 400 μm independent of the resin continuous phase, and the non-foamed skin layer in the thickness direction. The foamed molded product according to any one of [5] to [7], which has a sandwich structure of a foam layer.
[9] The thermoplastic polyester elastomer resin composition according to any one of [1] to [4] is melted in a cavity formed by a plurality of molds clamped with a chemical foaming agent and / or Injection and filling with an inert gas in a supercritical state, and expanding the volume of the cavity by moving at least one mold in the mold opening direction when a non-foamed skin layer having a thickness of 100 to 800 μm is formed on the surface layer A method for producing a foam-molded article.
[10] The method for producing a foam molded article according to [9], wherein the foam gas in a supercritical state is nitrogen.

  The thermoplastic polyester elastomer resin composition for foam molding of the present invention and the foamed molded product made thereof are not only excellent in light weight but also can exhibit a very high impact resilience. Furthermore, to provide a polyester foam molding that can be applied to parts that require high reliability because it has a uniform foaming state despite high foaming ratio, high heat resistance, water resistance, and molding stability. Can do.

It is a schematic block diagram for demonstrating an example of the manufacturing method of the foaming molding of this invention.

  Hereinafter, the thermoplastic polyester elastomer resin composition for foam molding of the present invention and the foam molded article using the same will be described in detail.

[Thermoplastic polyester elastomer (A)]
The thermoplastic polyester elastomer (A) used in the present invention is formed by bonding a hard segment and a soft segment. The hard segment is made of polyester. As the aromatic dicarboxylic acid constituting the hard segment polyester, ordinary aromatic dicarboxylic acids are widely used and are not particularly limited. However, as the main aromatic dicarboxylic acid, terephthalic acid or naphthalenedicarboxylic acid (in the isomer) 2,6-naphthalenedicarboxylic acid is preferred). The content of these aromatic dicarboxylic acids is preferably 70 mol% or more, and more preferably 80 mol% or more, based on the total dicarboxylic acid constituting the hard segment polyester. Other dicarboxylic acid components include diphenyldicarboxylic acid, isophthalic acid, aromatic dicarboxylic acid such as 5-sodiumsulfoisophthalic acid, cycloaliphatic dicarboxylic acid, alicyclic dicarboxylic acid such as tetrahydrophthalic anhydride, succinic acid, glutaric acid, Examples thereof include aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid and hydrogenated dimer acid. These can be used as long as the melting point of the resin is not greatly reduced, and the amount thereof is 30 mol% or less, preferably 20 mol% or less of the total acid component.

  In the thermoplastic polyester elastomer (A) used in the present invention, as the aliphatic or alicyclic diol constituting the hard segment polyester, general aliphatic or alicyclic diols are widely used, and are not particularly limited. However, it is desirable that they are mainly alkylene glycols having 2 to 8 carbon atoms. Specific examples include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and the like. Among these, either ethylene glycol or 1,4-butanediol is preferable.

  The components constituting the hard segment polyester include butylene terephthalate units (units consisting of terephthalic acid and 1,4-butanediol) or butylene naphthalate units (2,6-naphthalenedicarboxylic acid and 1,4-butanediol). From the viewpoints of physical properties, moldability, and cost performance.

  Further, when an aromatic polyester suitable as a polyester constituting the hard segment in the thermoplastic polyester elastomer (A) used in the present invention is produced in advance and then copolymerized with a soft segment component, the aromatic polyester is usually Can be easily obtained according to the production method of polyester. Moreover, what has the number average molecular weight 10000-40000 is desirable for this polyester.

  The soft segment of the thermoplastic polyester elastomer (A) used in the present invention is at least one selected from aliphatic polyether, aliphatic polyester, and aliphatic polycarbonate.

  Aliphatic polyethers include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, poly (trimethylene oxide) glycol, and a combination of ethylene oxide and propylene oxide. Examples thereof include a polymer, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Among these, from the viewpoint of elastic properties, an ethylene oxide adduct of poly (tetramethylene oxide) glycol or poly (propylene oxide) glycol is preferable.

  Examples of the aliphatic polyester include poly (ε-caprolactone), polyenantlactone, polycaprylolactone, and polybutylene adipate. Among these, poly (ε-caprolactone) and polybutylene adipate are preferable from the viewpoint of elastic properties.

  The aliphatic polycarbonate is preferably composed mainly of an aliphatic diol residue having 2 to 12 carbon atoms. Examples of these aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2, 2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8- Examples include octanediol. In particular, an aliphatic diol having 5 to 12 carbon atoms is preferable from the viewpoint of flexibility and low temperature characteristics of the obtained thermoplastic polyester elastomer. These components may be used alone or in combination of two or more as required, based on the case described below.

  The aliphatic polycarbonate diol having a low temperature characteristic and constituting the soft segment of the thermoplastic polyester elastomer (A) used in the present invention has a low melting point (for example, 70 ° C. or less) and a low glass transition temperature. preferable. In general, an aliphatic polycarbonate diol composed of 1,6-hexanediol used to form a soft segment of a thermoplastic polyester elastomer has a low glass transition temperature of around -60 ° C and a melting point of around 50 ° C. Good low temperature characteristics. In addition, an aliphatic polycarbonate diol obtained by copolymerizing an appropriate amount of, for example, 3-methyl-1,5-pentanediol with the above aliphatic polycarbonate diol has a glass transition point with respect to the original aliphatic polycarbonate diol. Although the melting point is slightly increased, the melting point is lowered or becomes amorphous, so that it corresponds to an aliphatic polycarbonate diol having good low-temperature characteristics. Also, for example, an aliphatic polycarbonate diol composed of 1,9-nonanediol and 2-methyl-1,8-octanediol has a melting point of about 30 ° C. and a glass transition temperature of about −70 ° C., which is sufficiently low. It corresponds to an aliphatic polycarbonate diol having good low-temperature characteristics.

  The soft segment of the thermoplastic polyester elastomer (A) used in the present invention is preferably an aliphatic polyether from the viewpoint of solving the problems of the present invention.

  The thermoplastic polyester elastomer (A) used in the present invention is preferably a copolymer containing terephthalic acid, 1,4-butanediol, and poly (tetramethylene oxide) glycol as main components. In the dicarboxylic acid component constituting the thermoplastic polyester elastomer (A), terephthalic acid is preferably 40 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, It is particularly preferably 90 mol% or more. In the glycol component constituting the thermoplastic polyester elastomer (A), the total of 1,4-butanediol and poly (tetramethylene oxide) glycol is preferably 40 mol% or more, more preferably 70 mol% or more. Preferably, it is 80 mol% or more, more preferably 90 mol% or more.

  The number average molecular weight of the poly (tetramethylene oxide) glycol is preferably 500 to 4000. If the number average molecular weight is less than 500, it may be difficult to develop elastomeric properties. On the other hand, if the number average molecular weight exceeds 4000, the compatibility with the hard segment component is lowered, and it may be difficult to copolymerize in a block form. The number average molecular weight of poly (tetramethylene oxide) glycol is more preferably 800 or more and 3000 or less, and further preferably 1000 or more and 2500 or less.

  In the thermoplastic polyester elastomer (A) used in the present invention, the soft segment content is preferably 45 to 90% by mass, more preferably 55 to 90% by mass, and still more preferably 60 to 90% by mass. When the content of the soft segment is lower than 45% by mass, the crystallinity is too high, so that the resilience is inferior.

  The thermoplastic polyester elastomer (A) used in the present invention can be produced by a known method. For example, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol, and a soft segment component are transesterified in the presence of a catalyst, and the resulting reaction product is polycondensed, A method in which a segment component is esterified in the presence of a catalyst and the resulting reaction product is polycondensed. A polyester of a hard segment is prepared in advance, and a soft segment component is added thereto and randomized by a transesterification reaction. Method, a method of linking a hard segment and a soft segment with a chain linking agent, and when poly (ε-caprolactone) is used for the soft segment, any method such as a method of adding an ε-caprolactone monomer to the hard segment may be used. .

[Thickener (B)]
The thickener (B) in the present invention is a reactive compound having a functional group capable of reacting with the hydroxyl group or carboxyl group of the thermoplastic polyester elastomer (A) (hereinafter sometimes simply referred to as a reactive compound). The functional group capable of reacting is preferably at least one selected from an epoxy group (glycidyl group), an acid anhydride group, a carbodiimide group and an isocyanate group, and the functional group contains at least two functional groups. . The functional group is more preferably an epoxy group (glycidyl group).

  When the thickener (B) is a compound having an epoxy group, as a polyfunctional epoxy compound having two or more epoxy groups, specifically, 1,6-dihydroxynaphthalenediglycidyl having two epoxy groups Ether, 1,3-bis (oxiranylmethoxy) benzene, 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4,6 having three epoxy groups (1H, 3H, 5H) -trione, diglycerol triglycidyl ether, 1-chloro-2,3-epoxypropane, formaldehyde, 2,7-naphthalenediol polycondensate having four epoxy groups and pentaerythritol polyglycidyl ether Is mentioned. Among these, a polyfunctional epoxy compound having heat resistance in the skeleton is preferable. In particular, a bifunctional or tetrafunctional epoxy compound having a naphthalene structure as a skeleton, or a trifunctional epoxy compound having a triazine structure as a skeleton is preferable. Considering the degree of increase in the solution viscosity of the thermoplastic polyester elastomer (A), the effect of efficiently reducing the acid value of the thermoplastic polyester elastomer (A), and the degree of gelation due to aggregation and solidification of the epoxy itself Then, a bifunctional or trifunctional epoxy compound is preferable.

  In addition, a vinyl aromatic monomer containing 2 or more glycidyl groups per molecule and having a weight average molecular weight of 4000 to 25000 and (X) 20 to 99% by mass, (Y) 1 to 80% by mass glycidyl ( Mention may be made of copolymers consisting of (meth) acrylates and (Z) vinyl group-containing monomers other than (X) which do not contain 0 to 79% by mass of epoxy groups.

  As the thickener (B) used in the present invention, a vinyl aromatic monomer containing two or more glycidyl groups per molecule and having a weight average molecular weight of 4000 to 25000 and (X) 20 to 99% by mass, A styrenic copolymer composed of (Y) 1 to 80% by mass of glycidyl (meth) acrylate and (Z) 0 to 79% by mass of a vinyl group-containing monomer other than (X) that does not contain an epoxy group, The compatibility with the plastic polyester elastomer is good, and the molecular weight distribution is wider, which is preferable. More preferably, the copolymer (X) is 20 to 99% by mass, (Y) is 1 to 80% by mass, and (Z) is 0 to 40% by mass, and more preferably (X) is 25 to 90%. It is a copolymer comprising 10% by mass, (Y) 10 to 75% by mass, and (Z) 0 to 35% by mass. Since these compositions affect the functional group concentration that contributes to the reaction with the thermoplastic polyester elastomer (A), it is preferable to appropriately control the composition within the above range.

  Examples of the (X) vinyl aromatic monomer include styrene and α-methylstyrene. Examples of the (Y) glycidyl alkyl (meth) acrylate include (meth) acrylic acid glycidyl, (meth) acrylic acid ester having a cyclohexene oxide structure, (meth) acrylic glycidyl ether, and the like. Glycidyl (meth) acrylate is preferred because of its high properties. Examples of the (Z) other vinyl group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylic having an alkyl group having 1 to 22 carbon atoms such as cyclohexyl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, etc. (the alkyl group may be linear or branched) Acid alkyl ester, (meth) acrylic acid polyalkylene glycol ester, (meth) acrylic acid alkoxyalkyl ester, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid dialkylaminoalkyl ester, (meth) acrylic acid benzyl ester, (Meth) acrylic acid phenoxyalkyl Ester, (meth) acrylic acid isobornyl ester, and (meth) acrylic acid alkoxysilyl alkyl ester. Also, (meth) acrylamide, (meth) acrylic dialkylamide, vinyl esters such as vinyl acetate, vinyl ethers, aromatic vinyl monomers such as (meth) allyl ethers, and α-olefin monomers such as ethylene and propylene Can also be used as the (Z) other vinyl group-containing monomer.

  The copolymer preferably has a weight average molecular weight of 4,000 to 25,000. The weight average molecular weight is more preferably 5000 to 15000. If the weight average molecular weight is less than 4000, the unreacted copolymer may volatilize in the molding step or bleed out on the surface of the molded product, which may cause surface contamination. On the other hand, when the weight average molecular weight exceeds 25,000, not only the reaction with the thermoplastic polyester elastomer (A) is delayed and the effect of increasing the molecular weight becomes insufficient, but also the copolymer and the thermoplastic polyester elastomer (A) Since compatibility becomes worse, the possibility that the properties such as heat resistance inherent in the thermoplastic polyester elastomer (A) will be increased.

The epoxy value of the copolymer is preferably 400-2500 equivalent / 1 × 10 ⁶ g, more preferably 500-1500 equivalent / 1 × 10 ⁶ g, and still more preferably 600-1000 equivalent / 1 × 10 g. ⁶ g. If the epoxy value is less than 400 equivalents / 1 × 10 ⁶ g, the effect of thickening may not be exhibited. On the other hand, if the epoxy value exceeds 2500 equivalents / 1 × 10 ⁶ g, the thickening effect becomes excessive and the moldability is increased. May cause adverse effects.

  When the thickener (B) is a compound having a carbodiimide group, a polycarbodiimide compound can be used. The polycarbodiimide compound is advantageous in that the acid value is efficiently reduced.

  The polycarbodiimide compound that can be used in the present invention may be any polycarbodiimide having two or more carbodiimide groups (structure of —N═C═N—) in one molecule, such as aliphatic polycarbodiimide and alicyclic ring. Aromatic polycarbodiimide, aromatic polycarbodiimide, and copolymers thereof. An aliphatic polycarbodiimide compound or an alicyclic polycarbodiimide compound is preferable.

  The polycarbodiimide compound can be obtained, for example, by a carbon dioxide removal reaction of a diisocyanate compound. Examples of the diisocyanate compound that can be used here include 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and 2,4-tolylene diisocyanate. 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, Examples include 1,3,5-triisopropylphenylene-2,4-diisocyanate. These may be used alone or in a combination of two or more. Moreover, you may introduce | transduce a branched structure or introduce | transduce functional groups other than a carbodiimide group or an isocyanate group by copolymerization. Furthermore, although the terminal isocyanate can be used as it is, the degree of polymerization may be controlled by reacting the terminal isocyanate, or a part of the terminal isocyanate may be blocked.

  As the polycarbodiimide compound, alicyclic polycarbodiimides derived from dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate and the like are particularly preferable, and polycarbodiimides derived from dicyclohexylmethane diisocyanate and isophorone diisocyanate are particularly preferable.

  The polycarbodiimide compound preferably contains 2 to 50 carbodiimide groups per molecule in terms of stability and handleability. More preferably, it should contain 5 to 30 carbodiimide groups per molecule. The number of carbodiimides in the polycarbodiimide molecule (that is, the number of carbodiimide groups) corresponds to the degree of polymerization if it is a polycarbodiimide obtained from a diisocyanate compound. For example, the polymerization degree of polycarbodiimide obtained by connecting 21 diisocyanate compounds in a chain form is 20, and the number of carbodiimide groups in the molecular chain is 20. Usually, a polycarbodiimide compound is a mixture of molecules of various lengths, and the number of carbodiimide groups is represented by an average value. Since it has the number of carbodiimide groups in the above range and is solid at room temperature, it can be pulverized, so it has excellent workability and compatibility when mixed with the thermoplastic polyester elastomer (A), uniform reactivity, and bleed-out resistance. This is also preferable. The number of carbodiimide groups can be measured using, for example, a conventional method (method of dissolving with amine and back titrating with hydrochloric acid).

  The polycarbodiimide compound preferably has an isocyanate group at the terminal and an isocyanate group content of 0.5 to 4% by mass from the viewpoint of stability and handleability. More preferably, the isocyanate group content is 1 to 3% by mass. In particular, it is a polycarbodiimide derived from dicyclohexylmethane diisocyanate or isophorone diisocyanate, and preferably has an isocyanate group content in the above range. The isocyanate group content can be measured by a conventional method (method of dissolving with amine and back titrating with hydrochloric acid).

  In the case where the thickener (B) is a compound having an isocyanate group, mention may be made of the above-described polycarbodiimide compound containing an isocyanate group and an isocyanate compound serving as a raw material for the above-described polycarbodiimide compound.

  When the thickener (B) is a compound having an acid anhydride group, a compound containing 2 to 4 anhydrides per molecule is preferable in terms of stability and handleability. Examples of such a compound include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like.

The content of the thickener (B) is 0.1 to 4.5 parts by weight, preferably 0.1 to 4 parts by weight, based on 100 parts by weight of the thermoplastic polyester elastomer (A). Preferably it is 0.1-3 mass parts.
When the thickener (B) is contained, if it is less than 0.1 parts by mass, the targeted molecular chain extension effect is insufficient, and if it exceeds 4.5 parts by mass, the thickening effect becomes excessive and molding is performed. There is a tendency to adversely affect the properties and affect the mechanical properties of the molded product. When the thickener (B) is an epoxy compound, if it exceeds 4.5 parts by mass, unevenness may occur on the surface of the molded product due to the aggregation and curing of the epoxy compound. When the thickener (B) is a carbodiimide compound, if it exceeds 4.5 parts by mass, the basicity of the polycarbodiimide compound tends to cause hydrolysis of the thermoplastic polyester elastomer (A) and affect the mechanical properties. .

  As described above, as the thickener (B), the epoxy compound, particularly two or more glycidyl groups per molecule, the weight average molecular weight is 4000 to 25000, and (X) 20 to 99% by mass. A styrene copolymer comprising a vinyl aromatic monomer, (Y) 1 to 80% by mass of glycidyl (meth) acrylate, and (Z) 0 to 79% by mass of a vinyl group-containing monomer other than (X) which does not contain an epoxy group. Polymers are preferred. When a compound having a reactive functional group such as a carbodiimide group is used in combination with an epoxy compound, the molecular weight distribution of the resin composition after thickening tends to be narrow. Therefore, the injection pressure at the time of injection molding becomes high, the foaming nuclei disappear, and the expansion ratio may be lowered. Therefore, in the resin composition of this invention, it is preferable not to use an epoxy compound and a carbodiimide compound together as a thickener.

[Other additives]
The resin composition of the present invention preferably contains a general-purpose antioxidant such as an aromatic amine, a hindered phenol, a phosphorus, or a sulfur. Two or more of these may be used in combination. Specific examples of the aromatic amine antioxidant used in the resin composition of the present invention include phenylnaphthylamine, 4,4′-dimethoxydiphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, and 4-isopropoxydiphenylamine and the like can be mentioned.

  Examples of hindered phenolic antioxidants include 3,5-di-t-butyl-4-hydroxy-toluene, n-octadecyl-β- (4′-hydroxy-3 ′, 5′-di-t-butylphenyl). ) Propionate, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6′-tris (3 , 5-Di-t-butyl-4-hydroxybenzyl) benzene, calcium (3,5-di-t-butyl-4-hydroxy-benzyl-monoethyl-phosphate), triethylene glycol-bis [3- ( 3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], penterythrityl-tetrakis [3- (3,5-di-tert-butylanilino) -1 3,5-triazine, 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] 2,4,8, 10-tetraoxaspiro [5,5] undecane, bis [3,3-bis (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, triphenol, 2,2′-ethylidenebis (4 , 6-di-t-butylphenol), N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2′-oxamidobis [ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,1,3-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) -S-triazine- 2 4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 3,5-di-tert-butyl -4-Hydroxyhydrocinnamic acid triester with-1,3,5-tris (2-hydroxyethyl) -S-triazine-2,4,6 (1H, 3H, 5H), N, N-hexamethylene Bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide) and the like can be mentioned.

  Examples of the phosphorus antioxidant include phosphorus-containing compounds such as phosphoric acid, phosphorous acid, hypophosphorous acid derivatives, phenylphosphonic acid, polyphosphonate, and diphosphite compounds. Specific examples include triphenyl phosphite, diphenyl decyl phosphite, phenyl diisodecyl phosphite, tri (nonylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2 , 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite.

  Examples of sulfur-based antioxidants include sulfur-containing compounds such as thioether-based, dithionate-based, mercaptobenzimidazole-based, thiocarbanilide-based, and thiodipropion ester-based compounds. Specific examples include dilauryl thiodipropionate, distearyl thiodipropionate, didodecyl thiodipropionate, ditetradecyl thiodipropionate, dioctadecyl thiodipropionate, pentaerythritol tetrakis (3-dodecyl thiopro Pionate), thiobis (N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, tri Examples include lauryl trithiophosphite.

  As for the compounding (content) amount of each said antioxidant, 0.01-3 mass parts is preferable with respect to 100 mass parts of thermoplastic polyester elastomer (A), More preferably, 0.05-2 mass parts, More preferably, it is 0.1-1 mass part. When 2 or more types of antioxidants are blended, the upper limit of the total content of antioxidants is preferably 5 parts by mass.

As a method of determining the composition and composition ratio of the polyester elastomer resin composition used in the present invention, it is also possible to calculate from a proton integration ratio of ¹ H-NMR measured by dissolving a sample in a solvent such as deuterated chloroform. is there.

  Furthermore, when weather resistance is required for the resin composition of the present invention, it is preferable to add an ultraviolet absorber and / or a hindered amine compound. For example, benzophenone-based, benzotriazole-based, triazole-based, nickel-based, and salicyl-based light stabilizers can be used. The addition amount is preferably 0.1% or more and 5% or less based on the mass of the resin composition.

Various other additives can be blended in the polyester elastomer resin composition of the present invention. Additives other than the above include resins, lubricants, fillers, flame retardants, flame retardant aids, mold release agents, antistatic agents, peroxides and other molecular modifiers, metal deactivators, organic and inorganic types In addition to nucleating agents, neutralizing agents, antacids, antibacterial agents, fluorescent whitening agents, organic and inorganic pigments, organic and inorganic phosphorus used for the purpose of imparting flame retardancy and thermal stability. Compound etc. are mentioned.
When the additive is contained, the content thereof (the total content when a plurality of additives are used) is preferably 30% by mass or less in the resin composition, more preferably 20% by mass or less, still more preferably Is 10% by mass or less, particularly preferably 5% by mass or less.

  The MFR value at 230 ° C. of the thermoplastic polyester elastomer resin composition for foam molding containing the above components is preferably 10 to 20 g / 10 min. And since MFR is 10-20 g / 10min, when carrying out foam molding of the polyester elastomer resin composition, it becomes difficult to produce the destruction of a cell wall, and the foam of a high expansion ratio can be obtained. In addition, when MFR is lower than 10 g / 10min, it exists in the tendency for fluidity | liquidity to fall, and when it is higher than 20 g / 10min, it exists in the tendency for foaming characteristics to fall.

[Foamed molded product]
The foamed molded product of the present invention is obtained using the above-described polyester elastomer resin composition of the present invention. Such a foamed molded article of the present invention comprises a non-foamed skin layer present on the surface layer and a foamed layer present on the inner layer, and these non-foamed skin and foamed layer are formed of the above-described polyester elastomer resin composition of the present invention. Therefore, it has a foam structure in a uniform cell state and can exhibit excellent lightness and rebound resilience.

  The foamed molded product of the present invention usually has a sandwich structure in which non-foamed skin layers are provided on both sides of the foamed layer (in other words, a structure in which the foamed layer is sandwiched between the non-foamed skin layers from both sides). . Although there is no restriction | limiting in particular regarding the size of a foaming molding, About 1-30 mm is assumed for the thickness direction of a sandwich structure.

The foam layer is composed of a resin continuous phase and an independent foam cell. Here, the resin continuous phase means a portion having no void formed by a cured polyester elastomer resin composition. The diameter of the foam cell (cell diameter) varies depending on the size as long as it is uniform and does not vary. In order to develop high resilience, a smaller cell diameter is advantageous, and specifically, an average cell diameter of 10 to 400 μm is preferable. When the average cell diameter is less than 10 μm, the internal pressure of the molded product is low, the pressure during formation of the non-foamed skin layer is insufficient, and the appearance such as sink marks tends to deteriorate. On the other hand, when the average cell diameter exceeds 400 μm, the load resistance is low and the resilience elastic modulus tends to be low. In addition, even if the cell diameter is small, if the density is high, the resilience is inferior. Therefore, if the foam structure having a density of 0.01 to 0.35 g / cm ³ described later is to exhibit high resilience, the average cell diameter is More preferably, it is 100-400 micrometers, More preferably, it is 200-400 micrometers. By applying an appropriate pressure to the non-foamed skin layer from the inside of the molded body, a foamed molded body having an average cell diameter in the above range can be obtained.

The non-foamed skin layer is laminated on the foamed layer and preferably has a thickness of 100 to 800 μm. When the thickness of the non-foamed skin layer is less than 100 μm, there is a tendency that a good appearance cannot be obtained. On the other hand, when the thickness exceeds 800 μm, the specific gravity of the foamed layer becomes too low. There is a tendency that a foamed structure of 0.01 to 0.35 g / cm ³ cannot be obtained in a uniform cell state. The thickness of the non-foamed skin layer is more preferably 200 to 600 μm, still more preferably 300 to 400 μm.

The density of the foamed molded product of the present invention is preferably 0.01 to 0.35 g / cm ³ . Since the density of a general polyester elastomer is about 1.0 to 1.4 g / cm ³ , it can be said that the foamed molded product of the present invention is sufficiently lightened. More preferably, it is 0.1 to 0.35 g / cm ³ . If the density is less than 0.01 g / cm ³ , sufficient strength cannot be obtained and the mechanical properties tend to be inferior, and if it exceeds 0.35 g / cm ³ , sufficient flexibility cannot be obtained and rebound resilience. Tend to be inferior. In order to achieve both excellent strength and high rebound resilience, the density of the foamed molded product is more preferably 0.01 to 0.25 g / cm ³ .

  The foamed molded article of the present invention has a uniform and fine cell structure because the average cell diameter is within a specific range, the density is within a specific range, and the non-foamed skin layer thickness is within a specific range. As a result, a high impact resilience of 60 to 90% can be realized. In order to develop high resilience characteristics, the resilience modulus of the foamed molded product is preferably 70 to 90%.

  The foaming method of the foamed molded article of the present invention is not particularly limited, but a foaming method in which the resin composition is impregnated with a high-pressure gas and then decompressed (releasing the pressure) is preferable. Among them, as a molding method for obtaining molding cycle performance, cost, and uniform foaming, a foamed molded article is obtained by expanding the volume of the cavity when melt-mixing the foaming agent and the polyester elastomer resin composition of the present invention and performing injection molding. The method is preferred. Specifically, as shown in FIG. 1, the polyester elastomer resin composition in a molten state is put into a chemical foaming agent and / or a supercritical state in a cavity 3 formed by a plurality of molds 1 and 2 clamped. At least one mold 2 is formed at a stage where a non-foamed skin layer having a thickness of 100 to 800 μm is formed on the surface layer by injection and filling with an inert gas (hereinafter sometimes referred to collectively as “foaming agent”). This is a method for obtaining a foamed molded article by moving in the opening direction and enlarging the volume of the cavity 3. Specifically, a non-foamed skin layer is formed on the surface layer of the polyester elastomer resin composition filled in the cavity 3 by filling the polyester elastomer resin composition and the foaming agent in the cavity 3 and then cooling at a predetermined temperature. Is done. When the non-foamed skin layer reaches a predetermined thickness (100 to 800 μm), the mold 2 is moved in the mold opening direction to expand the volume of the cavity 3. The thermoplastic polyester elastomer resin composition for foam molding and the foaming agent can be mixed in the plasticizing region 4a of the injection molding machine 4 before filling into the cavity 3.

The chemical foaming agent that can be used in obtaining the foamed molded article of the present invention is added to a resin that is melted in a resin melting zone of a molding machine as a gas component serving as a foaming nucleus or a generation source thereof.
Specifically, as the chemical foaming agent, inorganic compounds such as ammonium carbonate and sodium bicarbonate, and organic compounds such as azo compounds and sulfohydrazide compounds can be used. Examples of the azo compound include diazocarbonamide (ADCA), 2,2-azoisobutyronitrile, azohexahydrobenzonitrile, diazoaminobenzene, etc. Among them, ADCA is preferred and used. Examples of the sulfohydrazide compound include benzenesulfohydrazide, benzene 1,3-disulfohydrazide, diphenylsulfone-3,3-disulfonehydrazide and diphenyloxide-4,4-disulfonehydrazide. N, N-dinitrosopentaethylenetetramine (DNPT) and the like, and examples of the azide compound include terephthalazide and P-tert-butylbenzazide.

  When a chemical foaming agent is used as the foaming agent, the chemical foaming agent is made of a thermoplastic resin having a melting point lower than the decomposition temperature of the chemical foaming agent as a base material in order to uniformly disperse the polyester elastomer resin composition of the present invention. It can also be used as a foaming agent masterbatch. The base thermoplastic resin is not particularly limited as long as it has a melting point lower than the decomposition temperature of the chemical foaming agent, and examples thereof include polystyrene (PS), polyethylene (PE), and polypropylene (PP). In this case, the compounding ratio of the chemical foaming agent and the thermoplastic resin is preferably 10 to 100 parts by mass of the chemical foaming agent with respect to 100 parts by mass of the thermoplastic resin. When the chemical foaming agent is less than 10 parts by mass, the amount of the masterbatch with respect to the polyester elastomer resin composition of the present invention may increase so much that the physical properties may deteriorate. When it exceeds 100 parts by mass, it becomes difficult to form a masterbatch due to the problem of dispersibility of the chemical foaming agent.

  When an inert gas in a supercritical state is used as the foaming agent, carbon dioxide and / or nitrogen can be used as the inert gas. When carbon dioxide and / or nitrogen in a supercritical state is used as the foaming agent, the amount thereof is preferably 0.05 to 30 parts by mass with respect to 100 parts by mass of the polyester elastomer resin composition of the present invention. More preferably, it is 20 parts by mass. If the carbon dioxide and / or nitrogen in the supercritical state is less than 0.05 parts by mass, it becomes difficult to obtain uniform and fine foam cells, and if it exceeds 30 parts by mass, the appearance of the surface of the molded product tends to be impaired.

  In addition, although the supercritical carbon dioxide or nitrogen used as a blowing agent can be used alone, carbon dioxide and nitrogen may be mixed and used. Nitrogen tends to be more suitable for forming finer cells than the polyester elastomer resin composition, and carbon dioxide is suitable for obtaining a higher expansion ratio because a relatively large amount of gas can be injected. Therefore, it may be arbitrarily mixed with respect to the state of the adjusted foam structure, and the mixing ratio in the case of mixing is preferably in the range of 1: 9 to 9: 1 in terms of molar ratio.

  The foaming agent used in the present invention is more preferably nitrogen in a supercritical state from the viewpoint of uniform fine foaming.

  In order to inject the molten polyester elastomer resin composition into the cavity 3 together with the foaming agent, the molten polyester elastomer resin composition and the foaming agent may be mixed in the plasticizing region 4a of the injection molding machine 4. In particular, when carbon dioxide and / or nitrogen in a supercritical state is used as the foaming agent, for example, as shown in FIG. 1, the carbon dioxide and / or nitrogen in a gaseous state is pressurized directly or by a pressure pump 6 from a gas cylinder 5. A method of injecting into the injection molding machine 4 can be employed. These carbon dioxide and / or nitrogen need to be in a supercritical state inside the molding machine from the viewpoint of solubility, permeability and diffusibility in the molten polyester elastomer resin composition.

  Here, the supercritical state can eliminate the distinction between the gas phase and the liquid phase in a certain temperature range and pressure range when increasing the temperature and pressure of the substance generating the gas phase and the liquid phase. It means a state, and the temperature and pressure at this time are called critical temperature and critical pressure. In other words, since a substance has both gas and liquid characteristics in a supercritical state, a fluid generated in this state is called a critical fluid. Since such a critical fluid has a higher density than a gas and a lower viscosity than a liquid, it has a characteristic that it is very easy to diffuse in a substance.

  In order to demonstrate the effect of the present invention, examples will be given below, but the present invention is not limited to these examples.

The following raw materials were used in the following examples and comparative examples.
[Thermoplastic polyester elastomer (A)]
(Polyester elastomer A-1)
According to the method described in JP-A-9-59491, dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 2000 are used as raw materials, and the soft segment content is 78% by mass. A thermoplastic polyester elastomer was produced, and this was designated as polyester elastomer A-1.
(Polyester elastomer A-2)
According to the method described in JP-A-9-59491, dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 2000 are used as raw materials, and the soft segment content is 72% by mass. Was produced as polyester elastomer A-2.
(Polyester elastomer A-3)
According to the method described in JP-A-9-59491, dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 are used as raw materials, and the soft segment content is 59% by mass. Was produced as polyester elastomer A-3.
(Polyester elastomer A-4)
According to the method described in JP-A-9-59491, dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 are used as raw materials, and the soft segment content is 49% by mass. The thermoplastic polyester elastomer was manufactured and this was designated as polyester elastomer A-4.
(Polyester elastomer A-5)
According to the method described in JP-A-9-59491, dimethylterephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 are used as raw materials, and the soft segment content is 41% by mass. Was produced as polyester elastomer A-5.

[Thickener (B)]
(Styrene copolymer 1 (B-1))
The oil jacket temperature of a 1 liter pressurized stirred tank reactor equipped with an oil jacket was kept at 200 ° C. On the other hand, a monomer mixture comprising 89 parts by mass of styrene (St), 11 parts by mass of glycidyl methacrylate (GMA), 15 parts by mass of xylene (Xy) and 0.5 parts by mass of ditertiary butyl peroxide (DTBP) as a polymerization initiator. The liquid was charged into the raw material tank. This is continuously supplied from the raw material tank to the reactor at a constant supply rate (48 g / min, residence time: 12 minutes), and the reaction solution is discharged at the outlet of the reactor so that the content liquid mass of the reactor becomes constant at about 580 g. Extracted continuously. The reactor internal temperature at that time was kept at about 210 ° C. After 36 minutes from the stabilization of the temperature inside the reactor, the extracted reaction solution was led to a thin film evaporator maintained at a reduced pressure of 30 kPa and a temperature of 250 ° C., and continuously removed volatile components. A polymer (B-1) was obtained. The styrene copolymer (B-1) had a mass average molecular weight of 8500 and a number average molecular weight of 3300 according to GPC analysis (polystyrene equivalent value). Further, according to the following measurement method, the epoxy value is 670 equivalent / 1 × 10 ⁶ g, the epoxy value (the average number of epoxy groups per molecule) is 2.2, and the glycidyl group is contained in one molecule. It has two or more.
(Styrene copolymer 2 (B-2))
The polymer (B- 2) was obtained. This styrene copolymer (B-2) had a weight average molecular weight of 9700 and a number average molecular weight of 3300 according to GPC analysis (polystyrene equivalent value). The epoxy value is 1400 equivalent / 1 × 10 ⁶ g, the epoxy value (the average number of epoxy groups per molecule) is 4.6, and it has two or more glycidyl groups in one molecule.
(Polycarbodiimide (B-3))
A commercially available polycarbodiimide (“LA-1” manufactured by Nisshinbo Co., Ltd.) was prepared.
(Epoxy compound (B-4))
A commercially available epoxy compound (“TEPIC-S” manufactured by Nissan Chemical Co., Ltd.) was prepared.

[Method of measuring epoxy value]
A sample was weighed in a 100 ml ethylene Mayer flask, 10 to 15 ml of methylene chloride was added, and the mixture was stirred and dissolved with a magnetic stirrer. 10 ml of tetraethyleneammonium bromide reagent was added, 6-8 drops of crystal violet indicator were added, and neutralized with 0.1 N perchloric acid. The end point was changed from blue to green and stable for 2 minutes. The epoxy value was calculated based on the following formula, where A is the amount (ml) of perchloric acid required for the titration, W (g) is the sample mass, and N is the normality of the parrolic acid reagent.
Epoxy value (equivalent / 1 × 10 ⁶ g) = (N × A × 1000) / W

[Other additives]
Release agent:
Recolbe WE40 (manufactured by Clariant)
Hindered phenolic antioxidants:
Irganox 1010 (BASF)
Phosphorous antioxidants:
ADK STAB PEP36 (manufactured by ADEKA)
Benzotriazole UV absorber:
Tinuvin 234 (BASF)
Hindered amine light stabilizer:
Kimasorb 944FD (BASF)

Examples 1-8 (Example 8 is a reference example) , Comparative Examples 1-5
Examples 1-8 and Comparative Examples 1 to 8 were prepared by melting and kneading various components with respect to 100 parts by mass of the thermoplastic polyester elastomer according to the composition shown in Table 1 using a twin screw extruder. 5 pellets were obtained. In Comparative Example 2, the viscosity was increased in the extruder and a gel was generated.

  Next, using the thermoplastic polyester elastomer resin composition obtained above, a foamed molded article was produced by the above-described mold expansion method. As a mold, a cavity with a width of 100 mm, a length of 100 mm, and a thickness of 3 mm can be formed by clamping, and when the core is opened back in the mold opening direction, the thickness is the same, the length is 3 mm, and the core back amount (mm) A flat plate manufacturing mold made up of a fixing mold and an operation mold capable of forming a cavity was used. Specifically, in the plasticization region of an electric injection molding machine having a mold clamping force of 1800 kN, a screw diameter of 40 mm, and a screw stroke of 180 mm, supercritical nitrogen is injected to bring the surface temperature to 50 ° C. After injecting and filling the temperature-controlled mold, a non-foamed skin layer of 100 to 800 μm is formed by the external pressure of injection and the foaming pressure from the inside. It was moved by the length indicated as the amount (mm), and the volume of the cavity was expanded, to obtain a foamed molded article.

  The following evaluation was performed about the thermoplastic polyester elastomer resin composition for foam molding obtained in Examples 1 to 8 and Comparative Examples 1 to 5, and the foam molded body obtained from the resin composition. The results are shown in Table 1.

[MFR]
The MFR of the thermoplastic polyester elastomer resin composition for foam molding was measured at a load of 2,160 g and a measurement temperature of 230 ° C. according to the measurement method described in ASTM D1238.

[Density (apparent density)]
The dimensions of the polyester elastomer foam molding were measured with calipers, the mass was measured with an electronic balance, and the following formula was calculated.
Density (g / cm ³ ) = Mass of test piece / Volume of test piece

[Average cell diameter]
A foamed cross-section photograph of a cross-sectional observation sample taken with a scanning electron microscope SU1510 manufactured by Hitachi High-Technologies was subjected to image processing, and the circle equivalent diameter of at least 100 adjacent cells was taken as the cell diameter and measured with a caliper. The average value of these 100 pieces was obtained, and this was performed at any three locations, and a value obtained by averaging the three average values obtained at the three locations was taken as the average cell diameter.

[Skin layer thickness]
A photograph of the foamed cross-section of the sample for cross-sectional observation taken with a scanning electron microscope SU1510 manufactured by Hitachi High-Technologies was subjected to image processing, and the thickness of the integrated non-foamed layer found in the surface layer portion was measured as the skin layer thickness.

[Rebound resilience]
Measurement was carried out by the method described in JIS K 6400. Using a manual measurement tester, a steel ball was dropped on the test piece from the specified height, and the maximum height bounced was read. The measurement was performed three times within one minute, the median value was determined, and the rebound resilience was calculated.

  As is apparent from Table 1, Examples 1 to 8 which are within the scope of the present invention all exhibit light weight and high resilience. On the other hand, the comparative example 1 with few thickeners with respect to a polyester elastomer is inferior in resilience. In Comparative Example 2, which has too much thickener relative to the polyester elastomer, a gel is generated during extrusion. In Comparative Examples 2 to 4, the viscosity is too high to perform high-magnification foaming, and the lightness is inferior. Further, in Comparative Examples 2 and 4, since the viscosity is increased, foaming does not follow the core back amount. Comparative Example 5 having a low soft segment content of the polyester elastomer is inferior in resilience.

  The thermoplastic polyester elastomer resin composition for foam molding of the present invention and the foamed product made thereof are not only excellent in light weight but also can exhibit a very high rebound resilience. Furthermore, to provide a polyester foam molding that can be applied to parts that require high reliability because it has a uniform foaming state despite high foaming ratio, high heat resistance, water resistance, and molding stability. Can do.

1 Mold (for fixing)
2 Mold (for operation)
3 Cavity 4 Injection molding machine 4a Plasticizing region 5 Gas cylinder 6 Booster pump 7 Pressure control valve

Claims (7)

A hard segment comprising a polyester comprising an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol as a constituent, and at least one soft segment selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate; It is combined and contained in a proportion of 0.1 to 4.5 parts by mass of the thickener (B) with respect to 100 parts by mass of the thermoplastic polyester elastomer (A) having a soft segment content of 55 to 90% by mass. A foamed molded article comprising a thermoplastic polyester elastomer resin composition, having a density of 0.1 to 0.35 g / cm ³ and a rebound resilience of 60 to 90% . The thickener (B) contains two or more glycidyl groups per molecule, has a weight average molecular weight of 4000 to 25000, and (X) 20 to 99% by mass of a vinyl aromatic monomer, (Y) 1 to 80 It is a copolymer composed of a vinyl group-containing monomer other than (X) containing 0% to 79% by mass of glycidyl (meth) acrylate and (Z) containing no epoxy group. 2. The foamed molded article according to 1 . The thermoplastic polyester elastomer resin composition further comprises at least one antioxidant selected from an aromatic amine-based antioxidant, a hindered phenol-based antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant. The foamed molded product according to claim 1 or 2, comprising the antioxidant in a proportion of 0.01 to 3 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer (A). The foamed molded article according to any one of claims 1 to 3, wherein the thermoplastic polyester elastomer resin composition has an MFR at 230 ° C of 10 to 20 g / 10 min. The foamed molded product according to any one of claims 1 to 4, wherein the resilience modulus is 70% to 90%. The foam molded article according to any one of claims 1 to 5 , wherein the density is 0.1 to 0.25 g / cm ³ . The surface layer has a non-foamed skin layer with a thickness of 100 to 800 μm, the inner layer has a foamed layer made of foamed cells with an average cell diameter of 10 to 400 μm independent of the resin continuous phase, and the non-foamed skin layer and the foamed layer in the thickness direction The foam-molded article according to any one of claims 1 to 6 , which has a sandwich structure of: