Thermoplastic elastomer composition, molded article, method for manufacturing foamed molded article, and foamed molded article

Abstract

To provide a thermoplastic elastomer composition capable of obtaining a molded article excellent in flexibility, high temperature rigidity, lightness in weight and vibration-damping property.SOLUTION: There is provided a thermoplastic elastomer composition obtained by formulating a polyamide resin (A) having a melting point of 200°C or higher by differential scanning calorimetry (DSC); a copolymer (B) containing a polymer block mainly composed of an aromatic vinyl-based compound having a reactive functional group, and a polymer block and / or hydrogenated products thereof mainly composed of a conjugated diene-based compound; and a copolymer (C) containing a polymer block mainly composed of an aromatic vinyl compound other than the component (B), and a polymer block and / or hydrogenated products thereof mainly composed of a conjugated diene compound. The composition ratio (weight ratio) of the polyamide resin (A), the copolymer (B), and the copolymer (C) is (A):(B)=50:50 to 75:25, (B):(C)=90:10 to 25:75, and (A):((B)+(C))=40:60 to 60:40. In a morphology observed by using a transmission electron microscope, the average particle diameter of a black or white dispersed phase is 1.0 μm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer composition comprising a copolymer (B) containing a polyamide resin, a polymer block mainly composed of an aromatic vinyl compound having a reactive functional group, and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated product, and a copolymer (C) containing a polymer block mainly composed of an aromatic vinyl compound other than the component (B), a polymer block mainly composed of a conjugated diene compound, and / or its hydrogenated product, and a molded article using the same.

Background Art

[0002] Conventionally, as flexible polymer materials, those obtained by blending crosslinking agents, reinforcing agents, etc. with rubbers such as natural rubber or synthetic rubber and crosslinking them under high temperature and high pressure have been widely used. However, such rubbers have problems in that they require a process of crosslinking and molding under high temperature and high pressure for a long time and are inferior in processability. In addition, since crosslinked rubber does not exhibit thermoplasticity, recycling molding is generally impossible like thermoplastic resins. Therefore, various thermoplastic elastomers that can easily produce molded articles using general melt molding techniques such as injection molding, hot press molding, and extrusion molding have been developed in recent years.

[0003] Patent Document 1 discloses a thermoplastic resin composition having a good balance between rigidity and impact resistance, which comprises 0.5 to 50% by weight of a modified polar diene polymer having at least one group selected from the group consisting of an alkoxysilyl group, an amino group, an acid anhydride group, and a carboxyl group, and 50 to 99.5% of a polar resin, with a total of 100% by weight as the main component.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] However, the example specifically disclosed in Patent Document 1 is a resin composition consisting of a diene copolymer having a reactive functional group and polyamide 6. In this case, the amount of polyamide was too large, and sufficient flexibility could not be imparted.

[0006] The object of this invention is to provide a thermoplastic elastomer composition that can be easily molded and can produce molded articles that combine the properties of both polyamide and elastomer. [Means for solving the problem]

[0007] To achieve the above objective, the present invention has the following configuration. (1) A thermoplastic elastomer composition comprising a polyamide resin (A) having a melting point of 200°C or higher as determined by differential scanning calorimetry (DSC), a copolymer (B) containing a polymer block mainly composed of an aromatic vinyl compound having a reactive functional group and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivative, and a copolymer (C) containing a polymer block mainly composed of an aromatic vinyl compound other than component (B) and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivative, wherein the composition ratio (weight ratio) of the polyamide resin (A), copolymer (B), and copolymer (C) is (A):(B)=50:50~75:25, (B):(C)=90:10~25:75, and (A):((B)+(C))=40:60~60:40, and the average particle size of the black or white dispersed phase in the morphology observed by transmission electron microscopy is 1.0 μm or less. (2) The thermoplastic elastomer composition according to (1), wherein the polymer block mainly comprising the conjugated diene compound and / or its hydrogenated product is derived from at least one selected from isoprene, butadiene, ethylene-butylene, and ethylene-propylene. (3) The thermoplastic elastomer composition according to (1) or (2), wherein 0.01 to 10 parts by weight of a crystal nucleating agent (D) is added to 100 parts by weight of the thermoplastic elastomer composition. (4) The thermoplastic elastomer composition according to (3), wherein the nucleating agent (D) is an amide wax. (5) The thermoplastic elastomer composition according to (1) to (4), wherein 0.01 to 20 parts by weight of hydrogenated petroleum resin (E) is added to 100 parts by weight of the preceding thermoplastic elastomer composition. (6) A molded article comprising a thermoplastic elastomer composition as described in any one of items (1) to (5). (7) A method for producing a foamed molded article comprising the thermoplastic elastomer composition described in any one of (1) to (5), comprising the step of foaming the thermoplastic elastomer composition. (8) A foamed molded article comprising a thermoplastic elastomer composition as described in any one of items (1) to (5). [Effects of the Invention]

[0008] The thermoplastic elastomer composition of the present invention can be easily molded using general-purpose melt molding technology, and molded articles that combine the properties of both polyamide resin and thermoplastic elastomer can be obtained. In other words, the thermoplastic elastomer composition of the present invention is excellent in flexibility, rigidity at high temperatures (high-temperature rigidity), lightness, vibration damping, and recyclability, and can be used in applications such as automotive, electrical and electronic, and consumer goods. [Modes for carrying out the invention]

[0009] The present invention will be described in more detail below.

[0010] The present invention is a thermoplastic elastomer composition comprising a polyamide resin (A) (hereinafter sometimes abbreviated as polyamide resin (A)) having a melting point of 200°C or higher as determined by differential scanning calorimetry (DSC), a copolymer (B) (hereinafter sometimes abbreviated as copolymer (B)) containing a polymer block mainly composed of an aromatic vinyl compound having reactive functional groups and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivatives, and a copolymer (C) (hereinafter sometimes abbreviated as copolymer (C)) containing a polymer block mainly composed of an aromatic vinyl compound other than component (B) and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivatives.

[0011] By blending a copolymer (B) having reactive functional groups in a specific ratio with a polyamide resin (A) having excellent high-temperature rigidity and moldability, the polyamide resin (A) and copolymer (B) react appropriately, improving the flexibility of the composition, and also improving the compatibility between the polyamide resin (A) and copolymer (C). Furthermore, by blending copolymer (B) and copolymer (C) in a specific ratio, copolymer (B) and copolymer (C) interact appropriately, improving the compatibility between the polyamide resin (A) and copolymer (C), and making it possible to achieve both the crystallinity of the blended polyamide resin (A) and the flexibility of the copolymer (C). Moreover, by setting the ratio of the amount of polyamide resin (A) to the total amount of copolymer (B) and copolymer (C) to a specific ratio, the average particle size of the dispersed phase can be made 1.0 μm or less, and a thermoplastic elastomer composition that achieves both the crystallinity of the polyamide resin (A) and the flexibility of the copolymer (C) can be obtained. Furthermore, compositions having such morphology also exhibit excellent gas barrier properties.

[0012] The polyamide resin (A) used in the present invention is a polyamide resin with a melting point of 200°C or higher determined by DSC.

[0013] Here, the melting point of the polyamide resin (A) in the present invention can be determined by DSC using the following method. First, two-point calibration (indium, lead) and baseline correction are performed using a differential scanning calorimeter (DSC-7, manufactured by PerkinElmer). 8 to 10 mg of the polyamide resin sample is weighed, and the sample is heated at a heating rate of 20°C / min. The endothermic peak observed during the heating process is taken as the melting point.

[0014] If the melting point of the polyamide resin (A) is lower than 200°C, the high-temperature rigidity of the thermoplastic elastomer composition of the present invention decreases. The melting point of the polyamide resin (A) is preferably 205°C or higher, and preferably 210°C or higher.

[0015] On the other hand, there is no particular upper limit to the melting point of the polyamide resin (A), but it is preferable that it be 350°C or lower, as this tends not to degrade the mechanical properties of the copolymer (C), more preferably 320°C or lower, and even more preferably 300°C or lower.

[0016] Means for setting the melting point of the polyamide resin (A) within the above range include, for example, selecting a polyamide resin with a desired melting point from among polyamide resins with different melting points, or adjusting the degree of polymerization or copolymerization ratio of the polyamide resin.

[0017] The polyamide resin (A) is not particularly limited as long as it is a polyamide resin whose melting point satisfies the above conditions, but it can generally be obtained using amino acids, lactams or diamines and dicarboxylic acids as the main raw materials. Representative examples of these raw materials include, for example, amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, and 5-methylnonamethylenediamine; aromatic diamines such as metaxylenediamine and paraxylylenediamine; 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, and 2,2 Examples include alicyclic diamines such as bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine; aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid. In the present invention, polyamide homopolymers or copolymers derived from these raw materials can be used. Two or more such polyamide resins may be used.

[0018] Specific examples of the polyamide resin (A) preferably used in the present invention include polycaproamide (polyamide 6), polyhexamethylene adipamide (polyamide 66), polytetramethylene adipamide (polyamide 46), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyhexamethylene terephthalamide / polycaproamide copolymer (polyamide 6T / 6), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (polyamide 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 6T / 6I), polyhexamethylene terephthalamide / poly(2-methylpentamethylene) terephthalamide copolymer (polyamide 6T / M5T), polyxylylene adipamide (polyamide XD6), and mixtures or copolymers thereof. Particularly preferred are polyamide 6, polyamide 610, and polyamide 66.

[0019] The degree of polymerization of the polyamide resin (A) is not particularly limited, but the relative viscosity measured at 25°C in a 98% sulfuric acid solution with a resin concentration of 0.01 g / ml is preferably in the range of 1.5 to 7.0. If the relative viscosity is 1.5 or more, the melt viscosity of the polyamide resin composition during molding becomes moderately high, suppressing the entrainment of air during molding and further improving the moldability. On the other hand, if the relative viscosity is 7.0 or less, the melt viscosity of the thermoplastic elastomer composition during molding becomes moderately low, and the moldability can be further improved.

[0020] The amount of amino terminal groups in the polyamide resin (A) is not particularly limited, but is preferably in the range of 1.0×10 -5 ~12.0×10 -5 mol / g. When the amount of amino terminal groups is 1.0×10 -5~12.0×10 -5 If it is within the range of mol / g, a sufficient degree of polymerization can be obtained, and the mechanical strength of the molded product can be improved. Here, the amount of amino terminal groups of the polyamide resin (A) can be determined by dissolving the polyamide resin (A) in a phenol-ethanol mixed solvent (83.5:16.5 (volume ratio)) and titrating with a 0.02N hydrochloric acid aqueous solution.

[0021] The blending amount of the polyamide resin (A) of the present invention is such that the ratio (weight ratio) of the polyamide resin (A) to the copolymer (B) (A):(B) is 50:50 to 75:25, and the ratio (weight ratio) of the polyamide resin (A) to the total of the copolymer (B) and the copolymer (C) (A):((B)+(C)) is 40:60 to 60:40. When the ratio of the polyamide resin (A) is less than 50:50 compared to (A):(B), the crystallinity and high-temperature rigidity, which are characteristics of the polyamide resin (A), are not exhibited, which is not preferable. (A):(B) is preferably 50:50 to 75:25, more preferably 55:45 to 75:25, and even more preferably 60:40 to 75:25. Also, when the ratio of the polyamide (A) is more than 75:25 compared to (A):(B), the compatibility with the copolymer (C) decreases and the flexibility decreases, which is not preferable. Furthermore, regarding the ratio of the polyamide (A) to the total of the copolymer (B) and the copolymer (C), when the ratio of the polyamide resin (A) is less than 40:60 compared to (A):((B)+(C)), the average particle diameter of the dispersed phase becomes larger than 1.0 μm, and the crystallinity and high-temperature rigidity, which are characteristics of the polyamide resin (A), are not exhibited. On the other hand, when the ratio of the polyamide resin (A) is more than 60:40 compared to (A):((B)+(C)), the flexibility decreases, which is not preferable. (A):((B)+C)) is preferably 40:60 to 60:40, more preferably 40:60 to 55:45, and even more preferably 40:60 to 53:47.

[0022] The copolymer (B) used in the present invention is , Yoshi a copolymer containing a polymer block mainly composed of an aromatic vinyl-based compound and a polymer block mainly composed of a conjugated diene-based compound and / or its hydrogenated product. Having reactive functional groups copolymer.

[0023] The reactive functional group in copolymer (B) is not particularly limited, but examples include at least one selected from amino groups, carboxyl groups, carboxyl metal salts, hydroxyl groups, acid anhydrides, epoxy groups, isocyanate groups, mercapto groups, oxazoline groups, and sulfonic acid groups. Among these, amino groups, carboxyl groups, carboxyl metal salts, epoxy groups, acid anhydride groups, and oxazoline groups are preferred because they are highly reactive and produce few side reactions such as decomposition and crosslinking.

[0024] The acid anhydrides that constitute the acid anhydride group described above include maleic anhydride, itaconic anhydride, endicic anhydride, citraconic anhydride, and 1-butene-3,4-dicarboxylic acid anhydride. Two or more of these can be used in combination at the same time. Of these, maleic anhydride and itaconic anhydride are preferred.

[0025] A polymer block mainly composed of aromatic vinyl compounds is a polymer block in which units derived from aromatic vinyl compounds make up 60% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more.

[0026] Aromatic vinyl compounds include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, and α-chloro-o-chlorostyrene. Examples include α-chloro-m-chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, OT-butylstyrene, MT-butylstyrene, PT-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chloromethylstyrene, m-chloromethylstyrene, p-chloromethylstyrene, o-bromomethylstyrene, m-bromomethylstyrene, p-bromomethylstyrene, styrene derivatives substituted with silyl groups, indene, vinylnaphthalene, etc. Among these, styrene, α-methylstyrene, and mixtures thereof are preferred from the viewpoint of industrial availability and glass transition temperature.

[0027] A polymer block mainly composed of a conjugated diene compound is a polymer block in which units derived from the conjugated diene compound account for 60% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more.

[0028] Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and 1,3-hexadiene. One or more of these are selected and used.

[0029] Preferably, the polymers are isoprene, butadiene, ethylene-butene (a hydrogenated form of butadiene), and ethylene-propylene (a hydrogenated form of isoprene). There are no particular restrictions on the ratio of polymer blocks mainly composed of aromatic vinyl compounds to polymer blocks mainly composed of conjugated diene compounds, but from the viewpoint of flexibility, the content of polymer blocks mainly composed of aromatic vinyl compounds in copolymer (B) is preferably 10 to 50% by weight, and more preferably 10 to 40% by weight. If the content of polymer blocks mainly composed of aromatic vinyl compounds is 10% by weight or more, sufficient mechanical properties are exhibited, and if it is 50% by weight or less, flexibility can be obtained.

[0030] There are no particular restrictions on the molecular weight of copolymer (B), but from the viewpoint of moldability, fluidity, and rubber elasticity, it is preferable that the weight-average molecular weight measured by GPC is 5,000 to 400,000, and more preferably 10,000 to 200,000. If the weight-average molecular weight is 5,000 or more, sufficient mechanical properties are exhibited, while if it is 400,000 or less, the processability and fluidity of the molded product are excellent.

[0031] In this invention, the amount of copolymer (B) blended is such that the weight ratio of polyamide resin (A) to copolymer (B) (A):(B) is 50:50 to 75:25, the weight ratio of copolymer (B) to copolymer (C) (B):(C) is 90:10 to 25:75, and the weight ratio of polyamide resin (A) to the total of copolymer (B) and copolymer (C) (A):((B)+(C)) is 40:60 to 60:40. If the amount of copolymer (B) is greater than 50:50 in (A):(B), the reaction between polyamide resin (A) and copolymer (B) proceeds excessively, and the crystallinity and high-temperature rigidity, which are characteristics of polyamide resin, do not manifest. On the other hand, if the amount of copolymer (B) is less than 75:25 in (A):(B), flexibility decreases. The ratio of (A):(B) is preferably 50:50 to 75:25, more preferably 55:45 to 75:25, and even more preferably 60:40 to 75:25. Furthermore, if the amount of copolymer (B) in (B):(C) is greater than 90:10, the properties of copolymer (C) will not be expressed, and if the amount of copolymer (B) in (B):(C) is less than 25:75, the reactivity between the polyamide resin (A) and copolymer (B) will decrease, the average particle size of the dispersed phase will become larger than 1.0 μm, and the flexibility will decrease. The ratio of (B):(C) is preferably 90:10 to 25:75, more preferably 80:20 to 25:75, and even more preferably 75:25 to 25:75. Furthermore, if the ratio of (A):((B)+(C)) is greater than 40:60, the crystallinity and high-temperature rigidity, which are characteristics of the polyamide resin (A), will not be expressed. Furthermore, if (A):((B)+(C)) becomes less than 60:40, the compatibility with the polyamide resin (A) decreases, the average particle size of the dispersed phase becomes larger than 1.0 μm, and the flexibility decreases. (A):((B)+(C)) is preferably 40:60 to 60:40, more preferably 40:60 to 55:45, and even more preferably 40:60 to 53:47.

[0032] The amount of reactive functional groups introduced into the copolymer (B) is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, and even more preferably 0.1 to 5 parts by weight, per 100 parts by weight of copolymer (B). By introducing 0.1 parts by weight or more of reactive functional groups, the reactivity with the polyamide resin (A) can be increased. On the other hand, by keeping the amount of reactive functional groups to 20 parts by weight or less, the decrease in high-temperature rigidity can be suppressed.

[0033] The copolymer (C) used in the present invention is a copolymer comprising a polymer block mainly composed of aromatic vinyl compounds other than component (B), a polymer block mainly composed of conjugated diene compounds, and / or hydrogenated thereof. That is, it is a copolymer comprising a polymer block mainly composed of aromatic vinyl compounds that do not have reactive functional groups, a polymer block mainly composed of conjugated diene compounds, and / or hydrogenated thereof.

[0034] The aromatic vinyl compound in copolymer (C) is preferably the same compound as the compound described in copolymer (B) above.

[0035] The polymer block and / or hydrogenated polymer thereof in copolymer (C) is preferably derived from a polymer block similar to the compound described in copolymer (B) above.

[0036] The block copolymer (C) of the present invention is not particularly limited in its structure, as long as it is composed of a polymer block mainly composed of an aromatic vinyl compound and a polymer block mainly composed of a conjugated diene compound and / or hydrogenated thereof. For example, any of the following configurations can be selected: linear, branched, star-shaped, etc.

[0037] There are no particular restrictions on the ratio of polymer blocks mainly composed of aromatic vinyl compounds and polymer blocks mainly composed of conjugated diene compounds and / or their hydrogenated products. However, from the viewpoint of flexibility, the content of polymer blocks mainly composed of aromatic vinyl compounds in copolymer (C) is preferably 10 to 50% by weight, and more preferably 10 to 40% by weight. If the content of polymer blocks mainly composed of aromatic vinyl compounds is 10% by weight or more, sufficient mechanical properties are exhibited, and if it is 50% by weight or less, flexibility can be obtained.

[0038] Furthermore, there are no particular restrictions on the molecular weight of copolymer (C), but from the standpoint of moldability, fluidity, and rubber elasticity, it is preferable that the weight-average molecular weight measured by GPC is 5,000 to 400,000, and more preferably 10,000 to 200,000. When the weight-average molecular weight is 5,000 or more, sufficient mechanical properties are exhibited, while when it is 400,000 or less, the processability and fluidity of the molded product are excellent.

[0039] In the present invention, the amount of copolymer (C) blended is such that the ratio (weight ratio) of copolymer (B) to copolymer (C) is 90:10 to 25:75, and the ratio (weight ratio) (A):((B)+(C)) of polyamide resin (A) to the total of copolymer (B) and copolymer (C) is 40:60 to 60:40. If the amount of copolymer (C) in (B):(C) is less than 90:10, the properties of copolymer (C) will not be expressed, and if the amount of copolymer (C) in (B):(C) is more than 25:75, the reactivity between polyamide resin (A) and copolymer (B) will decrease, the average particle size of the dispersed phase will become larger than 1.0 μm, and the flexibility will decrease. The ratio of (B):(C) is preferably 90:10 to 25:75, more preferably 80:20 to 25:75, and even more preferably 75:25 to 25:75. Furthermore, if the ratio of ((B)+(C)) in (A):((B)+(C)) is greater than 40:60, the crystallinity and high-temperature rigidity characteristic of polyamide resins will not be exhibited. Also, if the ratio of ((B)+(C)) in (A):((B)+(C)) is less than 60:40, the compatibility between the polyamide resin (A) and the copolymer (B) decreases, the average particle size of the dispersed phase becomes larger than 1.0 μm, and the flexibility decreases. A ratio of (A):((B)+(C)) of 40:60 to 60:40 is preferred, 40:60 to 55:45 is more preferred, and 40:60 to 53:47 is even more preferred.

[0040] In this invention, compounds that fall under both component (B) and component (C) and have a reactive functional group are treated as component (B).

[0041] The copolymers (B) and (C) used in the present invention preferably have a glass transition temperature in the range of -60°C to 30°C.

[0042] The glass transition temperatures of copolymers (B) and (C) can be determined by the following method. A 40mm x 8mm x 1mm thick strip is cut from an 80mm x 80mm x 1mm thick plate made using copolymer (B) or copolymer (C) kept in an oven-dry state. The storage modulus and loss modulus are measured using a viscoelasticity analyzer (Seiko Instruments, DMS6100) under nitrogen atmosphere conditions, frequency of 100Hz, and heating rate of 2°C / min. The loss tangent can be obtained by dividing the loss modulus by the storage modulus. The peak temperature of the obtained loss tangent is taken as the glass transition temperature.

[0043] The glass transition temperature obtained at this time is preferably in the range of -60°C to 30°C, more preferably in the range of -50°C to 30°C, and even more preferably in the range of -45°C to 30°C. If the glass transition temperature is below -60°C or above 30°C, the value of the loss loss tangent at 23°C at a measurement frequency of 100 Hz becomes low, and vibration damping properties are not exhibited. Methods for setting the glass transition temperature in the range of -60°C to 30°C include, for example, adjusting the copolymerization ratio of copolymer (B) and copolymer (C).

[0044] The thermoplastic elastomer composition of the present invention is characterized in that, as observed by a transmission electron microscope (TEM), the average particle size of the black or white dispersed phase is 1.0 μm or less.

[0045] Here, the average particle size of the dispersed phase in a thermoplastic elastomer composition can be determined by the following method. An ultrathin section is cut from the composition pellet using an ultramicrotome, and this ultrathin section is stained with phosphotungstic acid or ruthenium tetroxide, and observed using a Hitachi H-7100 transmission electron microscope. The average particle size can then be calculated by image analysis. For the image analysis method, the image analysis software "Scion Image" from Scion Corporation is used to calculate the average of the major and minor axes of the dispersed phase stained white or black in the image, and the average particle size can be calculated as the average of the major and minor axes.

[0046] The average particle size of the dispersed phase is 1.0 μm or less, more preferably 800 nm or less, and even more preferably 500 nm or less. If the average particle size in the thermoplastic elastomer composition exceeds 1.0 μm, it is not possible to achieve both high-temperature rigidity and flexibility.

[0047] There are no particular restrictions on the lower limit of the average particle size of the dispersed phase in the thermoplastic elastomer composition, but it is preferably 1 nm or larger, more preferably 5 nm or larger, and even more preferably 10 nm or larger.

[0048] One method for reducing the average particle size of the dispersed phase to 1.0 μm or less is to use a polyamide resin (A) with reactive functional groups. copolymer By incorporating (B), the polyamide resin (A) and copolymer (B) react, improving the compatibility between the polyamide resin (A) and copolymer (C). Furthermore, by applying high shear stress and melt kneading, the reaction between the polyamide resin (A) and copolymer (B) proceeds further, making it possible to reduce the average particle size of the dispersed phase to 1.0 μm or less. Details will be described later.

[0049] In the morphology of the present invention, when stained with phosphotungstic acid, the polyamide resin (A) is stained black, and when stained with ruthenium tetroxide, the copolymers (B) and (C) are stained black. Therefore, for example, when stained with phosphotungstic acid, if the dispersed phase is observed to be black, it can be determined that the dispersed phase is mainly composed of polyamide resin (A), and if the dispersed phase is observed to be white, it can be determined that the dispersed phase is mainly composed of copolymer (C).

[0050] The present invention preferably comprises 0.01 to 10 parts by weight of a nucleating agent (D) per 100 parts by weight of a thermoplastic elastomer composition.

[0051] The nucleating agent (D) is not particularly limited as long as it enhances the formation of crystal nuclei in the polyamide resin (A). Examples of nucleating agents (D) include organic nucleating agents such as fatty acid metal salts, benzylidene sorbitol, quinacridone, cyanine blue, and amide waxes, and inorganic nucleating agents such as talc, clay, silica, and graphite. Two or more of these may be combined. Amide waxes are preferred from the viewpoint of making the crystals of the polyamide resin denser.

[0052] In the present invention, the amount of nucleating agent (D) is preferably 0.01 to 10 parts by weight per 100 parts by weight of the thermoplastic elastomer composition. An amount of 0.01 parts by weight or more improves the crystallinity of the polyamide resin (A) and enhances its high-temperature rigidity. On the other hand, an amount of 10 parts by weight or less is preferable because it suppresses the self-aggregation of the nucleating agent. The amount of nucleating agent is preferably 0.1 to 7.0 parts by weight, more preferably 0.5 to 6.0 parts by weight, and even more preferably 0.5 to 5.0 parts by weight.

[0053] The present invention preferably comprises 0.01 to 20 parts by weight of hydrogenated petroleum resin (E) per 100 parts by weight of thermoplastic elastomer composition.

[0054] Hydrogenated petroleum resin (E) is a resin that is obtained by hydrogenating petroleum resin, which is solidified using an acidic catalyst without isolating unsaturated hydrocarbons from the remaining fraction after thermal decomposition of petroleum naphtha and extraction of the necessary fractions, mainly from the C5 and C9 fractions.

[0055] Examples of the hydrogenated petroleum resins include hydrogenated dicyclopentadiene resins and partially hydrogenated aromatic-modified dicyclopentadiene resins, which are hydrogenated resins of C5 petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by the thermal decomposition of petroleum naphtha; C9 hydrogenated petroleum resins obtained by copolymerizing C9 fractions such as indene, vinyltoluene, and α- or β-methylstyrene produced by the thermal decomposition of petroleum naphtha; and copolymerized hydrogenated petroleum resins of the C5 fraction and the C9 fraction.

[0056] Examples of commercially available hydrogenated dicyclopentadiene resins include the Escolets® 5300 and 5400 series manufactured by Donex Co., Ltd., and the Eastotac® H series manufactured by Eastman Chemical Japan Co., Ltd.

[0057] Examples of commercially available partially hydrogenated aromatic-modified dicyclopentadiene resins include the Escorets® 5600 series manufactured by Tonex Co., Ltd.

[0058] Examples of commercially available C9-based hydrogenated petroleum resins include Alcon® P and M series manufactured by Arakawa Chemical Industries, Ltd., and Polystolyn manufactured by Eastman Chemical Company.

[0059] Examples of copolymerized hydrogenated petroleum resins of C5 and C9 fractions include the iMarb® series manufactured by Idemitsu Kosan Co., Ltd.

[0060] C9-based hydrogenated petroleum resin is preferred from the viewpoint of compatibility with copolymers (B) and (C). The amount of hydrogenated petroleum resin (E) in the present invention is preferably 0.01 to 20 parts by weight per 100 parts by weight of the thermoplastic elastomer composition. By increasing the amount to 0.01 parts by weight or more, the glass transition temperature of copolymers (B) and (C) can be shifted to the higher temperature side, and the loss tangent value of the thermoplastic elastomer composition at 23°C at a measurement frequency of 100 Hz can be increased. On the other hand, it is preferable to use 20 parts by weight or less because it can suppress surface tack due to bleed-out. The amount of hydrogenated petroleum resin is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 20 parts by weight, and even more preferably 1 to 15 parts by weight.

[0061] The thermoplastic elastomer composition of the present invention preferably has a loss tangent value of 0.1 or higher at 23°C with a measurement frequency of 100 Hz.

[0062] The loss tangent of a thermoplastic elastomer composition can be determined by the following method. A 40mm x 8mm x 1mm thick strip is cut from an 80mm x 80mm x 1mm thick plate made from a thermoplastic elastomer composition kept in an oven-dry state. The storage modulus and loss modulus are measured using a viscoelasticity measuring device (Seiko Instruments, DMS6100) under nitrogen atmosphere conditions, frequency of 100Hz, and heating rate of 2°C / min. The loss tangent at 23°C can be determined by dividing the loss modulus at 23°C by the storage modulus. By setting the loss tangent at 23°C at a measurement frequency of 100Hz to 0.1 or higher, the resulting thermoplastic elastomer composition can exhibit vibration damping properties. A method for setting the loss tangent at 0.1 or higher at a measurement frequency of 100Hz and a measurement temperature of 23°C can be, for example, by setting the glass transition temperature of the thermoplastic elastomer composition at a measurement frequency of 100Hz to -50°C to 30°C.

[0063] In this case, the glass transition temperature of the thermoplastic elastomer composition is preferably -50°C to 30°C, more preferably -45°C to 30°C, and even more preferably -45°C to 25°C. Methods for setting the glass transition temperature of the thermoplastic elastomer composition to -50°C to 30°C include using copolymers (B) and copolymer (C) having glass transition temperatures in the range of -60°C to 30°C, or incorporating the aforementioned hydrogenated petroleum resin (E). The temperature at which the loss tangent value of the thermoplastic elastomer composition is maximized (the peak temperature of the loss tangent) is defined as the glass transition temperature of the thermoplastic elastomer.

[0064] The thermoplastic elastomer composition of the present invention may contain other components besides components (A), (B), (C), (D), and (E) as needed, as long as their properties are not impaired. Examples of other components include fillers, copper compounds, potassium compounds, thermoplastic resins other than component (A), rubbery polymers without reactive functional groups other than component (C), and various additives.

[0065] For example, the strength and dimensional stability of molded products can be improved by incorporating fillers. However, the fillers in this invention do not include the inorganic nucleating agents mentioned above. The shape of the filler may be fibrous or non-fibrous, and fibrous and non-fibrous fillers may be used in combination. Examples of fibrous fillers include glass fibers, glass middle fibers, carbon fibers, potassium titanate whiskers, zinc oxide whiskers, aluminum nitrate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers. Examples of non-fibrous fillers include silicates such as wollastonite, zeolite, sericite, kaolin, mica, pyrophyllite, bentonite, asbestos, and alumina silicate; metal oxides such as alumina, magnesium oxide, zirconium oxide, titanium oxide, and iron oxide; metal carbonates such as calcium carbonate, magnesium carbonate, and dolomite; metal sulfates such as calcium sulfate and barium sulfate; metal hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide; glass beads, ceramic beads, boron nitride, and silicon carbide. These may be hollow. Furthermore, pre-treating these fibrous and / or non-fibrous fillers with a coupling agent is preferable from the viewpoint of obtaining better mechanical properties. Examples of coupling agents include isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds.

[0066] Examples of copper compounds include copper chloride, copper bromide, copper iodide, copper acetate, copper acetylacetonate, copper carbonate, copper borofluoride, copper citrate, copper hydroxide, copper nitrate, copper sulfate, and copper oxalate. Two or more of these copper compounds may be included. Among these copper compounds, those that are industrially available are preferred, and copper halides are preferred. Examples of copper halides include copper iodide, cuprous bromide, cupric bromide, and cuprous chloride. More preferably, the copper compound is copper iodide.

[0067] Examples of potassium compounds include potassium iodide, potassium bromide, potassium chloride, potassium fluoride, potassium acetate, potassium hydroxide, potassium carbonate, and potassium nitrate. Two or more of these potassium compounds may be included. Among these potassium compounds, potassium iodide is preferred. The inclusion of potassium compounds can improve the surface appearance, weather resistance, and mold corrosion resistance of the molded product.

[0068] Potassium compounds suppress the liberation and precipitation of copper, and it is believed that using both copper and potassium compounds together promotes the reaction between the copper compound and the polyamide resin (A).

[0069] Examples of thermoplastic resins include polyamide resins other than component (A), polyester resins, polyphenylene sulfide resins, polyphenylene oxide resins, polycarbonate resins, polylactic acid resins, polyacetal resins, polysulfone resins, tetrafluoroethylene resins, polyetherimide resins, polyamideimide resins, polyimide resins, polyethersulfone resins, polyetherketone resins, polythioetherketone resins, polyetheretherketone resins, styrene-based resins such as polystyrene resin and ABS resin, and polyalkylene oxide resins. It is also possible to blend two or more of these thermoplastic resins. When blending polyamide resins other than component (A), it is preferable to blend them in amounts of 4 parts by weight or less per 100 parts by weight of polyamide resin (A).

[0070] Examples of rubbery polymers that do not have reactive functional groups other than component (C) include styrene-based rubbers other than (C), olefin-based resins, acrylic-based rubbers, silicone-based rubbers, fluoro-based rubbers, nitrile-based rubbers, vinyl-based rubbers, urethane-based rubbers, polyamide elastomers, polyester elastomers, and ionomers. Two or more of these may be blended.

[0071] The structure of the rubbery polymer is not particularly limited, and may be a multilayer structure known as a core-shell type, for example, consisting of at least one layer made of rubber and one or more layers made of a different type of polymer. The number of layers constituting the multilayer structure may be two or more, or it may be three or more or four or more, but it is preferable to have one or more rubber layers (core layers) inside. The type of rubber constituting the rubber layer of the multilayer structure is not particularly limited, and examples include rubber obtained by polymerizing acrylic components, silicone components, styrene components, nitrile components, conjugated diene components, urethane components, ethylene components, propylene components, isobutene components, etc. The type of different polymer constituting the layers other than the rubber layer of the multilayer structure is not particularly limited as long as it is a thermoplastic polymer, but polymers with a higher glass transition temperature than the rubber layer are preferred. Examples of thermoplastic polymers include polymers containing unsaturated carboxylic acid alkyl ester units, unsaturated carboxylic acid units, unsaturated glycidyl group-containing units, unsaturated dicarboxylic acid anhydride units, aliphatic vinyl units, aromatic vinyl units, vinyl cyanide units, maleimide units, unsaturated dicarboxylic acid units and other vinyl units.

[0072] Examples of various additives include color inhibitors, antioxidants such as hindered phenols and hindered amines, mold release agents such as ethylene bisstearylamide and higher fatty acid esters, plasticizers, heat stabilizers, lubricants, UV inhibitors, colorants, flame retardants, and foaming agents.

[0073] Next, a method for producing the thermoplastic elastomer composition of the present invention will be described. Examples of methods for producing the thermoplastic elastomer composition of the present invention include a method of kneading a polyamide resin (A), copolymer (B), copolymer (C), and other components together as needed. As the kneading apparatus, known kneading apparatuses such as Banbury mixers, rolls, and extruders can be used. When other components, such as various additives, are incorporated into the thermoplastic elastomer composition of the present invention, these can be incorporated at any stage. For example, when producing the thermoplastic elastomer composition of the present invention using a twin-screw extruder, methods include simultaneously incorporating other components when incorporating the polyamide resin (A), copolymer (B), and copolymer (C); incorporating other components by a method such as side-feeding during melt-kneading of the polyamide resin (A), copolymer (B), and copolymer (C); or incorporating other components into the polyamide resin (A) and copolymer (B) beforehand, melt-kneading, and then incorporating copolymer (C). In particular, in the present invention, it is preferable to melt-knead at high shear stress in order to obtain a morphology in which the dispersed phase has an average particle size of 1.0 μm or less. By kneading under high shear stress, the polyamide resin (A) and copolymer (B) react appropriately, improving the compatibility between the polyamide resin (A) and copolymer (C), thereby reducing the average particle size of the dispersed phase to 1.0 μm or less. Examples of kneading under high shear stress include kneading at a high rotational speed, using an extruder in which the L / D ratio of the kneading zone is 20% or more of the L / D ratio of the extruder, and increasing the residence time in the extruder. The rotational speed is preferably 170 rpm or higher, more preferably 190 rpm, and even more preferably 200 rpm. There is no particular upper limit, but from the viewpoint of suppressing resin decomposition, 600 rpm or less is preferred. The ratio of the L / D ratio of the kneading zone to the L / D ratio of the extruder is preferably 20% or more, more preferably 25% or more, and even more preferably 30% or more. From the viewpoint of productivity, an upper limit of 60% or less is preferred.

[0074] The thermoplastic elastomer composition of the present invention can be molded by any method to obtain a molded article, and any shape can be formed. Examples of molding methods include extrusion molding, injection molding, hollow molding, calendering, compression molding, vacuum molding, foam molding, blow molding, and rotational molding. Examples of molded shapes include pellet shape, plate shape, fibrous shape, strand shape, film or sheet shape, pipe shape, hollow shape, and box shape.

[0075] The thermoplastic elastomer composition of the present invention is preferably subjected to foam molding. Examples of foam molding methods include adding a foaming agent to the thermoplastic elastomer composition during melt-kneading and then molding after melt-kneading; chemical foaming, which involves dry-blending the foaming agent with the thermoplastic elastomer composition of the present invention before molding; and physical foaming, which involves impregnating the thermoplastic elastomer composition with supercritical gas and then molding, or impregnating a thermoplastic elastomer composition molded in an autoclave with supercritical gas and then foaming it. Physical foaming is preferred from the viewpoint of productivity and quality.

[0076] The supercritical gas used during physical foaming is not particularly limited as long as it can dissolve in the thermoplastic elastomer composition and is inert; however, carbon dioxide and nitrogen are preferred from the standpoint of safety and cost. The amount of supercritical gas used is preferably 0.01 to 20 parts by weight, and more preferably 0.05 to 10 parts by weight, per 100 parts by weight of the thermoplastic elastomer composition.

[0077] Because the molded articles of the present invention are excellent in flexibility, high-temperature rigidity, and lightweight properties, they can be suitably used in applications such as automotive, electrical and electronic, and consumer electronics. [Examples]

[0078] The effects of the present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Evaluations in each example and comparative example were performed by the following method.

[0079] (1) Melting point of polyamide resin The melting points of the polyamide resins used in each example and comparative example were determined by DSC. First, a differential scanning calorimeter (DSC-7, PerkinElmer) was used, and two-point calibration (indium and lead) and baseline correction were performed. 8-10 mg of polyamide resin was weighed and heated at a heating rate of 20°C / min. The melting point was defined as the endothermic peak temperature observed during the heating process.

[0080] (2) Glass transition temperature of copolymer (B) and copolymer (C) The glass transition temperatures of copolymers (B) and (C) used in each example and comparative example were determined by viscoelastic measurement. First, a 40mm × 8mm × 1mm thick strip was cut from an 80mm × 80mm × 1mm thick plate prepared using copolymer (B) or copolymer (C) kept in an oven-dry state. The storage modulus and loss modulus were measured using a viscoelastic measuring device (Seiko Instruments, DMS6100) under nitrogen atmosphere, frequency of 100Hz, and heating rate of 2°C / min to determine the storage modulus and loss modulus. The loss tangent was obtained by dividing the loss modulus by the storage modulus. The peak temperature of the obtained loss tangent was defined as the glass transition temperature.

[0081] (3) Average particle size of the dispersed phase in the thermoplastic elastomer composition Ultrathin sections were cut from the pellets obtained in each example and comparative example using an ultramicrotome. These ultrathin sections were stained with phosphotungstic acid and then observed at 10,000x magnification using a Hitachi H-7100 transmission electron microscope. The average particle size of the white or black dispersed phase was calculated by image analysis. For image analysis, the image analysis software "Scion Image" from Scion Corporation was used to calculate the average values ​​of the major and minor diameters of the dispersed particles present in the image, and the average particle size was calculated as the average of the major and minor diameters.

[0082] (4) Flexibility: Shore D hardness Three 80mm x 80mm x 3mmt rectangular plates obtained from each example and comparative example were stacked, and their Shore D hardness was evaluated using a durometer-hardness tester (Type D) in accordance with ASTM D2240-05 under conditions of 23°C and 50% humidity.

[0083] (5) High-temperature rigidity: melting point and heat of fusion The melting points of the resin composition pellets obtained in each example and comparative example were determined by DSC measurement. First, a differential scanning calorimeter (DSC-7, PerkinElmer) was used, and two-point calibration (indium, lead) and baseline correction were performed. 8-10 mg of the resin composition was weighed and heated at a heating rate of 20°C / min. The melting point was defined as the endothermic peak temperature observed during the heating process. Furthermore, the heat of fusion was determined from the area of ​​the endothermic peak temperature.

[0084] (6) Lightweight: Specific gravity From the 80mm x 80mm x 3mmt rectangular plates obtained in each example and comparative example, strips measuring 10mm x 80mm x 3mmt were cut, and their specific gravity was measured according to ISO 1183:1987.

[0085] (7) Productivity: Blocking The pellets obtained from each example and comparative example were vacuum-dried at 80°C for 15 hours. The adhesion (blocking) of the pellets during this process was observed.

[0086] (8) Gas barrier properties: Oxygen permeability coefficient Using the 80mm x 80mm x 3mmt flat plates obtained in each example and comparative example, the oxygen permeability coefficient was evaluated using a GTR-10 (manufactured by Yanaco Analytical Industries) at a temperature of 23°C and a differential pressure of 0.15 MPa, in accordance with JIS K7126 Method A (differential pressure method) (1987 edition).

[0087] (9) Loss tangent: vibration damping From the 80mm × 80mm × 1mmt flat plates prepared using the thermoplastic elastomer compositions obtained in each example and comparative example, strips measuring 40mm × 8mm × 1mmt were cut out. The storage modulus and loss modulus were determined by measuring them using a viscoelasticity measuring device (Seiko Instruments, DMS6100) under a nitrogen atmosphere at a measurement frequency of 100Hz and a heating rate of 2°C / min. The loss tangent was calculated by dividing the loss modulus by the storage modulus. The value of the loss tangent at 23°C and the temperature at which the loss tangent is maximized (peak temperature of the loss tangent) were determined.

[0088] The raw materials and abbreviations used in each example and comparative example are shown below. PA6: Polyamide 6 resin "Amiran" (registered trademark) manufactured by Toray Industries, Inc. (melting point 224°C, relative viscosity 2.70 at 25°C in a 98% concentrated sulfuric acid solution with a resin concentration of 0.01 g / ml) (corresponds to polyamide resin (A)). PA12: Polyamide 12 resin "DAIAMID" (registered trademark) manufactured by Daicel Evonik Co., Ltd. (melting point 178°C) SEBS-g-MAH: Maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, manufactured by Kraton Polymers Japan Co., Ltd., "Kraton" (registered trademark) FG1924 (styrene content 13.9%, Tg=-55℃) (corresponds to copolymer (B)). SIS: Styrene-isoprene-styrene block copolymer "Krayton Polymer Japan Co., Ltd. "Krayton" (registered trademark) D1161 (styrene content 15%, Tg=-50℃) (corresponds to copolymer (C))." SBS: Styrene-butadiene-styrene copolymer "Krayton Polymer Japan Co., Ltd. "Krayton" (registered trademark) D1102 (styrene content 29%, Tg = -90℃) (corresponds to copolymer (C))" SEBS: Styrene-ethylene-butylene-styrene block copolymer "Krayton Polymers Japan Co., Ltd. "Krayton" (registered trademark) G1645VO (styrene content 13%, Tg=-25℃) (corresponds to copolymer (C))." SEPS: Styrene-ethylene-propylene-styrene block copolymer "Krayton Polymers Japan Co., Ltd. "Krayton" (registered trademark) G1730 (styrene content 20%, Tg=-45℃) (corresponds to copolymer (C))." Amide wax: Ethylenediamine-stearic acid-sebacic acid polycondensate "Light Amid" WH-255 (Kyoeisha Chemical Co., Ltd., melting point 255°C) (corresponds to crystal nucleating agent (D)). Hydrogenated petroleum resin: C9-type hydrogenated petroleum resin "Alcon" P-140 (Arakawa Chemical Industries, Ltd.) (Category E of hydrogenated petroleum resin).

[0089] [Examples 1-10, 12, Comparative Examples 1-6] The raw materials listed in Table 1 were supplied to a twin-screw extruder (TEX30XSSST, manufactured by JSW) with a cylinder temperature set to 250°C, a screw arrangement with two kneading zones, and a screw rotation speed of 250 rpm (L / D = 45.5 (where L is the length from the raw material supply port to the discharge port, and D is the screw diameter), kneading zone ratio: 30%) for melting and kneading. The gut extruded from the die was rapidly cooled by passing it through a cooling bath filled with water heated to 10°C for 15 seconds to fix its structure, and then pelletized using a strand cutter to obtain pellets. The obtained pellets were used to form 80mm × 80mm × 3mmt square plates and 80mm × 80mm × 1mmt square plates using an injection molding machine (SE-75DUZ-C250) manufactured by Sumitomo Heavy Industries, Ltd., under molding conditions of a mold temperature of 30°C, an injection speed of 40mm / sec, and a cooling time of 60 seconds. The injection molding machine temperature was set to 240°C-245°C-250°C-250°C from the bottom of the hopper towards the tip. The results of evaluation using the obtained pellets or molded products by the above method are shown in Table 1.

[0090] [Example 11] Using the raw materials listed in Table 1, pellets were obtained by pelletizing under the same conditions as in Example 1. The obtained pellets were core-back molded into 80mm × 80mm × 3mmt square plates and 80mm × 80mm × 1mmt square plates using a physical foam molding machine manufactured by Japan Steel Works Ltd. under molding conditions of a mold temperature of 30°C, an injection speed of 40mm / sec, a cooling time of 60 seconds, and carbon dioxide as the supercritical fluid. The temperature of the injection molding machine was set to 240°C-245°C-250°C-250°C from the bottom of the hopper towards the tip. The results of evaluation using the obtained pellets or molded products by the above method are shown in Table 1.

[0091] [Comparative Example 7] Pelletization was performed using the raw materials listed in Table 1 under the same conditions as in Example 1, except that the screw rotation speed was set to 150 rpm, to obtain pellets. The obtained pellets were then molded into 80mm × 80mm × 3mmt square plates and 80mm × 80mm × 1mmt square plates using a Sumitomo Heavy Industries, Ltd. injection molding machine (SE-75DUZ-C250) under molding conditions of a mold temperature of 30°C, an injection speed of 40mm / second, and a cooling time of 60 seconds. The temperature of the injection molding machine was set to 240°C-245°C-250°C-250°C from the bottom of the hopper towards the tip. The results of evaluation using the obtained pellets or molded products by the above method are shown in Table 1.

[0092] [Table 1]

[0093] [Table 2]

[0094] From the above results, thermoplastic elastomer compositions were obtained by blending a polyamide resin (A) with a melting point of 200°C or higher as determined by DSC measurement, a copolymer (B) containing a polymer block mainly composed of an aromatic vinyl compound having a reactive functional group and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivative, and a copolymer (C) containing a polymer block mainly composed of an aromatic vinyl compound other than component (B) and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated derivative, wherein the composition ratio (weight ratio) of (A), (B), and (C) was (A):(B)=50:50~75:25, (B):(C)=90:10~25:75, and (A):((B)+(C))=40:60~60:40. When observed with a transmission electron microscope, these thermoplastic elastomer compositions showed an average particle size of 1.0 μm or less in the dispersed phase. The thermoplastic elastomer composition was found to be excellent in flexibility, high-temperature rigidity, and lightweight properties, and did not exhibit blocking during drying. Furthermore, it was found that the elastomer compound possessing these properties also had excellent vibration damping properties. [Industrial applicability]

[0095] Molded articles made from the thermoplastic elastomer composition of the present invention exhibit excellent flexibility, high-temperature rigidity, lightness, and vibration damping, and do not undergo blocking during drying, and are also easy to manufacture. Taking advantage of these properties, the thermoplastic elastomer composition of the present invention can be widely used in various molded articles, and is particularly suitable for automotive, electrical and electronic, and consumer applications.

Claims

1. A thermoplastic elastomer composition comprising: (A) a polyamide resin having a melting point of 200°C or higher as determined by differential scanning calorimetry (DSC); (B) a copolymer having a reactive functional group comprising a polymer block mainly composed of an aromatic vinyl compound and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated counterpart; and (C) a copolymer comprising a polymer block mainly composed of an aromatic vinyl compound other than component (B) and a polymer block mainly composed of a conjugated diene compound and / or its hydrogenated counterpart, wherein the reactive functional group is an amino group A thermoplastic elastomer composition comprising at least one selected from the group consisting of carboxyl groups, carboxyl metal salts, epoxy groups, acid anhydride groups, and oxazoline groups, wherein the composition ratio (weight ratio) of polyamide resin (A), copolymer (B), and copolymer (C) is (A):(B) = 50:50 to 75:25, (B):(C) = 90:10 to 25:75, and (A):((B) + (C)) = 40:60 to 60:40, and the average particle size of the black or white dispersed phase in the morphology observed by transmission electron microscopy is 1.0 μm or less.

2. The thermoplastic elastomer composition according to claim 1, wherein the polymer block mainly comprising the conjugated diene compound and / or its hydrogenated product is a polymer block derived from at least one selected from isoprene, butadiene, ethylene-butylene, and ethylene-propylene.

3. The thermoplastic elastomer composition according to claim 1 or 2, comprising 0.01 to 10 parts by weight of a crystal nucleating agent (D) per 100 parts by weight of the thermoplastic elastomer composition.

4. The thermoplastic elastomer composition according to claim 3, wherein the nucleating agent (D) is an amide wax.

5. The thermoplastic elastomer composition according to claim 1 or 2, wherein 0.01 to 20 parts by weight of hydrogenated petroleum resin (E) is added to 100 parts by weight of the thermoplastic elastomer composition.

6. A molded article comprising the thermoplastic elastomer composition according to claim 1 or 2.

7. A method for producing a foamed molded article, comprising the step of foaming the thermoplastic elastomer composition according to claim 1 or 2.

8. A foamed molded article comprising the thermoplastic elastomer composition according to claim 1 or 2.

Images