Thermoplastic elastomer compositions, injection molded articles, and automotive interior parts

Abstract

To provide a thermoplastic elastomer composition which has excellent fluidity and can reduce the stickiness of an obtained molded product; an injection molded product containing the composition; and an automobile interior part comprising the injection molded product.SOLUTION: There is provided a thermoplastic elastomer composition which comprises a propylene-based polymer (A), an ethylene / an α-olefin copolymer (B) containing ethylene and an α-olefin unit having 3 to 20 carbon atoms, a hydrogenated product of a block copolymer, a softening agent (D) and an inorganic filler (E), wherein the content of the softening agent (D) is 100 to 250 pts.mass based on 100 pts.mass of the propylene-based polymer (A) and the content of the inorganic filler (E) is 15 to 100 pts.mass based on 100 pts.mass of the propylene-based polymer (A).SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a thermoplastic elastomer composition, an injection molded article containing the thermoplastic elastomer composition, and an automotive interior part made of the injection molded article.

Background Art

[0002] A so-called dynamically crosslinked thermoplastic elastomer composition, which is obtained by crosslinking a resin having no radical crosslinkability such as polypropylene (PP) and a radical crosslinkable elastomer while melt-kneading them in an extruder in the presence of a radical initiator, is widely used in automotive parts such as interior skin materials.

[0003] As such rubber-based compositions, olefin-based elastomer compositions using ethylene-propylene-diene rubber (EPDM) and the like are known (see Patent Document 1 and Patent Document 2). Further, a composition obtained by dynamically crosslinking a hydrogenated rubber is also known (see Patent Document 3 and Patent Document 4). Furthermore, a thermoplastic elastomer composition using a hydrogenated product of a copolymer of an olefin-based resin, a vinyl aromatic compound, and a conjugated diene compound has been disclosed (see Patent Document 5 and Patent Document 6).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

[0005] Thermoplastic elastomer compositions used in automotive interior surface materials, particularly those for injection molding, generally require high fluidity. Therefore, it is common practice to add large amounts of softener to the composition. However, adding large amounts of softener tends to cause the softener to bleed onto the surface of the molded product, resulting in stickiness and a loss of tactile feel. In recent years, from the perspective of automotive design, there has been a demand to suppress the stickiness of the surface of automotive interior upholstery materials while increasing the fluidity of the composition. Therefore, there is a desire for the realization of thermoplastic elastomer compositions that fully satisfy all of these performance requirements.

[0006] In view of the above situation, this disclosure provides a thermoplastic elastomer composition that has excellent fluidity and can suppress stickiness of molded products, an injection molded product containing the composition, and an automotive interior part made from the injection molded product. [Means for solving the problem]

[0007] In other words, the present invention relates to the following [1] to [8]. [1] Propylene polymer (A), Ethylene-α-olefin copolymer (B) containing ethylene and α-olefin units having 3 to 20 carbon atoms, Hydrogenated block copolymer (C), Softener (D), and Inorganic filler (E) Includes, The content of the softening agent (D) is 100 to 250 parts by mass per 100 parts by mass of the propylene polymer (A), The amount of the inorganic filler (E) is 15 to 100 parts by mass per 100 parts by mass of the propylene polymer (A). A thermoplastic elastomer composition characterized by the following features.

[0008] [2] The thermoplastic elastomer composition according to item [1], wherein the inorganic filler contains calcium carbonate.

[0009] [3] The thermoplastic elastomer composition according to item [1] or [2], wherein the content of the ethylene-α-olefin copolymer (B) is 40 to 180 parts by mass with respect to 100 parts by mass of the propylene-based polymer (A).

[0010] [4] The thermoplastic elastomer composition according to any one of items [1] to [3], wherein the content of the hydrogenated product (C) of the block copolymer is 50 to 250 parts by mass with respect to 100 parts by mass of the propylene-based polymer (A).

[0011] [5] The thermoplastic elastomer composition according to any one of items [1] to [4], which is dynamically heat-treated.

[0012] [6] The thermoplastic elastomer composition according to any one of items [1] to [5], wherein at least a part of the ethylene-α-olefin copolymer (B) is crosslinked.

[0013] [7] An injection molded article containing the thermoplastic elastomer composition according to any one of items [1] to [6].

[0014] [8] An automotive interior part made of the injection molded article according to item [7]. [Advantages of the Invention]

[0015] According to the present disclosure, it is possible to provide a thermoplastic elastomer composition having excellent fluidity and capable of suppressing the stickiness of a molded article, an injection molded article containing the composition, and an automotive interior part made of the injection molded article. [Embodiments for Carrying out the Invention]

[0016] In this disclosure, unless otherwise specified, the expressions "XX or greater and YY or less" and "XX to YY" that represent a numerical range mean a numerical range that includes the lower and upper limits. Furthermore, when numerical ranges are listed in steps, the upper and lower limits of each numerical range can be combined in any way. Furthermore, the phrase "A and / or B" is a concept that includes the cases of A, B, and both A and B.

[0017] <Propylene-based polymer (A)> A propylene-based polymer (A) [hereinafter sometimes referred to as "component (A)"], which is one of the components of the thermoplastic elastomer composition of this disclosure, is a polymer in which the content of propylene-derived structural units among the structural units constituting the polymer is 50 mol% or more, and preferably the content of propylene-derived structural units in component (A) is 90 mol% or more. The component (A) relating to this disclosure may be one type or two or more types. Component (A) relating to this disclosure may be a propylene homopolymer or a copolymer of propylene and a comonomer other than propylene.

[0018] The structure of component (A) relating to this disclosure is not particularly limited; for example, the propylene-derived constituent unit portion may be an isotactic, syndiotactic, or atactic structure. Furthermore, the copolymer may be random (also referred to as random PP), block (also referred to as block PP: bPP), or graft type.

[0019] The comonomer can be any other monomer copolymerizable with propylene, and α-olefins having 2 or 4 to 10 carbon atoms are preferred. Specifically, examples include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene, among which ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene are preferred. One comonomer may be used, or two or more may be used. The content of comonomer-derived structural units in the copolymer is preferably 10 mol% or less, from the viewpoint of flexibility and other factors.

[0020] Component (A) relating to this disclosure may be synthesized by conventionally known methods or a commercially available product may be used. Examples of commercially available products include polypropylene from Sun Allomer Co., Ltd., Prime Polypropylene from Prime Polymer Co., Ltd., Novatec from Nippon Polypropylene Co., Ltd., and SCG PP from SCG Plastics Co., Ltd.

[0021] Component (A) relating to this disclosure may be a crystalline polymer or an amorphous polymer. Here, crystalline means that a melting point (Tm) is observed in differential scanning calorimetry (DSC). If component (A) of the present disclosure is a crystalline polymer, its melting point (according to the measurement method of JIS K 7121) is preferably 100°C or higher, more preferably 120°C or higher, preferably 180°C or lower, and more preferably 170°C or lower, from the viewpoint of heat resistance and the like.

[0022] The MFR (measured according to the ASTM D 1238-65T method, at 230°C and a 2.16 kg load) of component (A) relating to this disclosure is preferably 0.1 to 100 g / 10 min, and more preferably 0.1 to 50 g / 10 min. When the MFR of component (A) relating to this disclosure is within the above range, a composition with excellent heat resistance, mechanical strength, fluidity, and moldability can be easily obtained.

[0023] <Ethylene-α-olefin copolymer (B)> One of the components contained in the thermoplastic elastomer composition of this disclosure is an ethylene-α-olefin copolymer (B) that contains units derived from ethylene and units derived from α-olefins having 3 to 20 carbon atoms.

[0024] The ethylene-α-olefin copolymer (B) (hereinafter sometimes referred to as "component (B)") relating to this disclosure can be obtained by copolymerizing ethylene with at least an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene. Among these, from the viewpoint of imparting flexibility, α-olefins having 5 to 12 carbon atoms are preferred, propylene, 1-butene, and 1-octene are more preferred, and 1-octene is even more preferred.

[0025] Component (B) according to this disclosure typically contains 70 to 99 mol%, preferably 80 to 97 mol%, of units derived from ethylene, and 1 to 30 mol%, preferably 3 to 20 mol%, of units derived from α-olefins having 3 to 20 carbon atoms [provided that the total amount of units derived from ethylene and units derived from α-olefins having 3 to 20 carbon atoms is 100 mol%]. The content ratio of units derived from ethylene being within the above range is preferable for obtaining a thermoplastic elastomer composition with excellent mechanical strength.

[0026] Component (B) of the present disclosure may be copolymerized with monomers having unsaturated bonds as needed. Preferred monomers having unsaturated bonds include, for example, conjugated diolefins such as butadiene and isoprene, unconjugated diolefins such as 1,4-hexadiene; cyclic diene compounds such as dicyclopentadiene and norbornene derivatives; and acetylenes. Among these, ethylidene norbornene (ENB) and dicyclopentadiene (DCPD) are more preferred from the viewpoint of flexibility. Component (B) relating to this disclosure typically has an MFR (ASTM D1238 load 2.16 kg, temperature 190°C) in the range of 0.1 to 20 g / 10 min, preferably 0.3 to 10 g / 10 min. By setting the MFR within the above range, a thermoplastic elastomer composition with superior balance characteristics between fluidity and mechanical strength can be obtained.

[0027] The component (B) relating to this disclosure typically has a density of 0.8 to 0.9 g / cm³. 3 It is within the range. Component (B) relating to this disclosure can be produced using known polymerization catalysts such as Ziegler-Natta catalysts, vanadium-based catalysts, and metallocene catalysts. The polymerization method is not particularly limited and can be carried out using liquid-phase polymerization methods such as solution polymerization, suspension polymerization, and bulk polymerization, gas-phase polymerization, and other known polymerization methods. Furthermore, these copolymers are not limited as long as they achieve the effects of this disclosure and are available as commercial products. Examples of commercial products include Engage 8842 (ethylene-1-octene copolymer) from Dow Chemical, Vistalon® from ExxonMobil, Esprene® from Sumitomo Chemical Co., Ltd., Mitsui EPT®, Tuffmer P®, and Tuffmer A® from Mitsui Chemicals, Inc.

[0028] <Hydrogenated block copolymer (C)> The hydrogenated block copolymer (C) contained in the thermoplastic elastomer composition of this disclosure (hereinafter, this may be referred to as "component (C)", "hydrogenated product (C)", or "hydrogenated product (C)") is a hydrogenated block copolymer having at least one block mainly composed of conjugated diene monomer units and at least one block mainly composed of vinyl aromatic monomer units. Component (C) relating to this disclosure is obtained by hydrogenating (hereinafter sometimes referred to as "hydrogenation") at least a portion of monomer units derived from a conjugated diene monomer.

[0029] Here, "vinyl aromatic monomer unit" refers to the constituent unit of a polymer resulting from the polymerization of vinyl aromatic monomers, and its structure is a molecular structure in which the two carbon atoms of a substituted ethylene group derived from a substituted vinyl group are bonded. Similarly, "conjugated diene monomer unit" refers to the constituent unit of a polymer resulting from the polymerization of conjugated dienes, and its structure is a molecular structure in which the two carbon atoms of an olefin derived from a conjugated diene monomer are bonded.

[0030] In component (C) relating to this disclosure, "mainly" means that the copolymer block contains 50% by mass or more, preferably 60% by mass or more, and more preferably 80% by mass or more, monomer units derived from a conjugated diene monomer (or vinyl aromatic monomer). For example, a block mainly consisting of conjugated diene monomer units means that the block contains 50% by mass or more, preferably 60% by mass or more, and more preferably 80% by mass or more, monomer units derived from a conjugated diene monomer.

[0031] The vinyl aromatic monomer in component (C) of this disclosure is not particularly limited, and examples include vinyl aromatic compounds such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. These may be used individually or in combination of two or more. Among these, styrene is preferred from an economic standpoint.

[0032] The conjugated diene monomer in component (C) of this disclosure is a diolefin having one pair of conjugated double bonds, and examples include 1,3-butadiene (butadiene), 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. Among these, butadiene and isoprene are preferred from the viewpoint of economy. These may be used individually or in combination of two or more.

[0033] The arrangement of each block in component (C) relating to this disclosure is not particularly limited, and a suitable arrangement can be adopted as appropriate. For example, if a polymer block consisting of vinyl aromatic monomer units is represented by S, and a polymer block consisting of units in which at least a portion of conjugated diene monomer units is hydrogenated is represented by B, then the hydrogenated products of this block copolymer are SB, S(BS) n1 (Here, n1 represents an integer from 1 to 3.) S(BSB) n2 Linear block copolymers represented by (where n² represents an integer between 1 and 2), etc., and (SB) n3 Copolymers represented by X (where n3 represents an integer from 3 to 6, and X represents a coupling agent residue such as silicon tetrachloride, tin tetrachloride, or a polyepoxy compound) are examples. Among these, linear block copolymers of type 2 (diblock) of SB, type 3 (triblock) of SBS, and type 4 (tetrablock) of SBSB are preferred.

[0034] Here, polymer block B may be a polymer block consisting only of conjugated diene monomer units, or a polymer block mainly containing conjugated diene monomer units and also containing vinyl aromatic monomer units (conjugated diene monomer units and vinyl aromatic monomer units copolymerized), and in either case, at least a portion of the conjugated diene monomer units is hydrogenated.

[0035] The content of vinyl aromatic monomer units in component (C) relating to this disclosure is 10 to 80% by mass, preferably 20 to 70% by mass, and more preferably 20 to 60% by mass, from the viewpoint of heat resistance and dispersibility. By increasing the content of vinyl aromatic monomer units to 10% by mass or more, the mechanical properties can be further improved, and by decreasing it to 80% by mass or less, the low-temperature properties can be further improved. The content of vinyl aromatic monomer units in component (C) relating to this disclosure can be measured by nuclear magnetic resonance spectroscopy (NMR).

[0036] The content of vinyl aromatic monomer unit blocks in component (C) relating to this disclosure is preferably 10% by mass or more, and more preferably 10 to 40% by mass, from the viewpoint of mechanical strength. Here, the content of vinyl aromatic compound polymer blocks in component (C) is defined by the following formula, using the mass of vinyl aromatic compound polymer blocks obtained by a method of oxidative decomposition of the copolymer before hydrogenation with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in IM Kolthoff, et al., J. Polym. Sci. 1, 429 (1946), hereinafter also referred to as the "osmium tetroxide decomposition method") (where vinyl aromatic compound polymers with an average degree of polymerization of about 30 or less are excluded). Vinyl aromatic compound polymer block content (mass%) = (Mass of vinyl aromatic compound polymer blocks in copolymer before hydrogenation / Mass of copolymer before hydrogenation) × 100

[0037] If multiple polymer blocks exist in component (C) of this disclosure, their structures, such as molecular weight and composition, may be the same or different. For example, component (C) may contain a hydrogenated copolymer block containing conjugated diene monomer units and vinyl aromatic monomer units, and a hydrogenated copolymer block mainly composed of conjugated diene monomer units. The boundaries and ends of each block do not necessarily need to be clearly distinguishable. The distribution of vinyl aromatic monomer units in each polymer block is not particularly limited and may be uniformly distributed, tapered, stepped, convex, or concave. Furthermore, crystalline portions may be present in the polymer block.

[0038] The distribution of vinyl units of conjugated diene monomer units in each polymer block within component (C) of this disclosure is not particularly limited, and for example, the distribution may be biased. Methods for controlling the distribution of vinyl units include adding a vinylizing agent during polymerization and changing the polymerization temperature. Furthermore, the distribution of hydrogenation rates of conjugated diene monomer units may also be biased. The distribution of hydrogenation rates can be controlled by changing the distribution of vinyl units, or by copolymerizing isoprene and butadiene and then hydrogenating using a hydrogenation catalyst described later, utilizing the difference in hydrogenation rates between isoprene units and butadiene units. Component (C) relating to this disclosure is characterized in that, from the viewpoint of heat resistance, aging resistance, and weather resistance, preferably 75 mol% or more, more preferably 85 mol% or more, and even more preferably 97 mol% or more of the unsaturated bonds contained in the conjugated diene monomer unit before hydrogenation are hydrogenated.

[0039] The hydrogenation catalyst used is not particularly limited and is generally known. (1) Supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, Ru are supported on carbon, silica, alumina, diatomaceous earth, etc. (2) A so-called Ziegler-type hydrogenation catalyst using organic acid salts such as Ni, Co, Fe, Cr or transition metal salts such as acetylacetone salt and a reducing agent such as organoaluminum, (3) Homogeneous hydrogenation catalysts such as organometallic compounds like Ti, Ru, Rh, and Zr, or so-called organometallic complexes, can be used.

[0040] Specific hydrogenation catalysts that can be used include those described in Japanese Patent Publication No. 42-008704, Japanese Patent Publication No. 43-006636, Japanese Patent Publication No. 63-004841, Japanese Patent Publication No. 01-037970, Japanese Patent Publication No. 01-053851, Japanese Patent Publication No. 02-009041, etc. Among these, preferred hydrogenation catalysts include reducing organometallic compounds such as titanocene compounds.

[0041] Examples of titanocene compounds include those described in Japanese Patent Publication No. 08-109219, and specific examples include compounds having at least one ligand with a (substituted) cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton, such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride.

[0042] Examples of reducing organometallic compounds include organoalkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

[0043] The polymerization method for the block copolymer before hydrogenation in component (C) relating to this disclosure is not particularly limited, and known methods may be employed. Examples include the methods described in Japanese Patent Publication No. 36-019286, Japanese Patent Publication No. 43-017979, Japanese Patent Publication No. 46-032415, Japanese Patent Publication No. 49-036957, Japanese Patent Publication No. 48-002423, Japanese Patent Publication No. 48-004106, Japanese Patent Publication No. 56-028925, Japanese Unexamined Patent Publication No. 59-166518, Japanese Unexamined Patent Publication No. 60-186577, etc.

[0044] If necessary, component (C) may have a polar group. Examples of polar groups include hydroxyl groups, carboxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, acid anhydride groups, thiocarboxylic acid groups, aldehyde groups, thioaldehyde groups, carboxylic acid ester groups, amide groups, sulfonic acid groups, sulfonic acid ester groups, phosphoric acid groups, phosphoric acid ester groups, amino groups, imino groups, nitrile groups, pyridyl groups, quinoline groups, epoxy groups, thioepoxy groups, sulfide groups, isocyanate groups, isothiocyanate groups, silicon halide groups, alkoxysilicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronic acid bases, alkoxytin groups, and phenyltin groups.

[0045] The vinyl bond content in the conjugated diene monomer units in the block copolymer before hydrogenation of component (C) relating to this disclosure is preferably 5 mol% or more from the viewpoint of flexibility and scratch resistance, and preferably 70 mol% or less from the viewpoint of productivity, elongation at break, and scratch resistance. The vinyl bond content in the conjugated diene monomer units is more preferably 10 to 50 mol%, even more preferably 10 to 30 mol%, and still more preferably 10 to 25 mol%.

[0046] In this context, vinyl bond content refers to the proportion of 1,2- and 3,4-bonded structures within the 1,2-, 3,4-, and 1,4-bonded structures of the conjugated diene before hydrogenation. Vinyl bond content can be measured by NMR.

[0047] The weight-average molecular weight of component (C) before crosslinking is not particularly limited, but from the viewpoint of scratch resistance, it is preferably 50,000 or more, from the viewpoint of moldability, it is preferably 400,000 or less, and more preferably 50,000 to 300,000. The molecular weight distribution (Mw / Mn: weight-average molecular weight / number-average molecular weight) is not particularly limited, but from the viewpoint of scratch resistance, it is preferably close to 1. The weight-average molecular weight and number-average molecular weight can be determined by gel permeation chromatography (GPC; Shimadzu Corporation, instrument name "LC-10") using tetrahydrofuran (1.0 mL / min) as the solvent and an oven temperature of 40°C, with columns: TSKgelGMHXL (4.6 mm ID × 30 cm, 2 columns). The weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) are calculated as polystyrene-equivalent molecular weight.

[0048] Examples of commercially available components (C) related to this disclosure include SOE S1606, S1613, and ToughTec H1041, H1062, and H1221 (all registered trademarks) manufactured by Asahi Kasei Corporation.

[0049] <Softener (D)> The softener (D) [hereinafter sometimes referred to as "component (D)"], which is one of the components contained in the thermoplastic elastomer composition of this disclosure, is not particularly limited, and any softener commonly used for rubber can be used. From the viewpoint of compatibility with the above-mentioned propylene polymer (A) and ethylene-α-olefin copolymer (B), a process oil consisting of hydrocarbons such as paraffinic, naphthenic, and aromatic hydrocarbons is preferred. Among these components (D), a process oil mainly composed of paraffinic hydrocarbons is preferred from the viewpoint of weather resistance and colorability, and a process oil mainly composed of naphthenic hydrocarbons is preferred from the viewpoint of compatibility. From the viewpoint of thermal and light stability, the content of aromatic hydrocarbons in the process oil is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less, in terms of the carbon number ratio specified in ASTM D2140-97.

[0050] <Inorganic filler (E)> The inorganic filler (E) [hereinafter sometimes referred to as "component (E)"], which is one of the components contained in the thermoplastic elastomer composition of this disclosure, is not particularly limited, and inorganic fillers commonly used in rubber can be used. Specifically, examples include metal carbonates, sulfates, phosphates, oxides, hydroxides, silicon-containing inorganic materials, sulfides, carbon materials, and cement. The component (E) relating to this disclosure may be one type or two or more types.

[0051] Examples of the aforementioned carbonates include calcium carbonate, barium carbonate, magnesium carbonate, and zinc carbonate. Examples of the sulfates include calcium sulfate, barium sulfate, and magnesium sulfate. Examples of the phosphate include calcium phosphate.

[0052] Examples of the aforementioned oxides include zinc oxide, iron oxide, calcium oxide, magnesium oxide, aluminum oxide, titanium oxide, and barium oxide. Examples of the hydroxide include magnesium hydroxide.

[0053] Examples of silicon-containing inorganic materials include calcium silicate, clay (including pyrophyllite clay, calcined clay, etc.), kaolin, talc, silica (including fumed silica, calcined silica, precipitated silica, crushed silica, fused silica, etc.), diatomaceous earth, mica, asbestos, glass fiber, glass spheres, shirasu balloons, silicate clay, and zeolite.

[0054] Examples of the aforementioned sulfides include tungsten sulfide and molybdenum sulfide. Examples of the carbon material include graphite and carbon black.

[0055] Among these inorganic fillers, calcium carbonate, barium carbonate, magnesium carbonate, zinc carbonate, calcium sulfate, barium sulfate, magnesium sulfate, zinc oxide, iron oxide, calcium oxide, magnesium oxide, aluminum oxide, titanium oxide, barium oxide, calcium silicate, clay, kaolin, talc, and carbon black are preferred, talc, clay, and calcium carbonate are more preferred, talc and calcium carbonate are even more preferred, and talc is particularly preferred.

[0056] The shape of component (E) is not particularly limited and may be in various forms such as granular, plate-like, rod-like, fibrous, or whisker-like, but plate-like is preferred. The weight-average particle size of component (E) is not particularly limited, but from the viewpoint of dispersibility, handling during manufacturing, and mechanical properties, it is preferably 10.0 μm or less, more preferably 9.0 μm or less, and preferably 0.5 μm or more.

[0057] The weight-average particle size can be measured, for example, by a laser diffraction particle size distribution analyzer. Component (E) may be an inorganic filler whose surface is coated with fatty acids or fatty acid derivatives.

[0058] Examples of the aforementioned fatty acids include linear saturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and melissic acid, as well as unsaturated fatty acids such as cetoleic acid and sorbic acid.

[0059] Examples of the fatty acid derivatives include fatty acid esters and fatty acid metal salts. Fatty acid esters are preferably esters of higher fatty acids having 8 or more carbon atoms, such as stearyl stearate, lauryl stearate, stearyl palmitate, lauryl palmitate, glyceride tristearate, and glyceride tripalmitate. Fatty acid metal salts include sodium salts, potassium salts, calcium salts, aluminum salts, and zinc salts of fatty acids having 10 to 25 carbon atoms.

[0060] <Polyorganosiloxane (F)> The structure of polyorganosiloxane (F), which may be included in the thermoplastic elastomer composition of this disclosure (hereinafter sometimes referred to as "component (F)"), is not particularly limited, but from the viewpoint of abrasion resistance and tactile feel, it is preferable to have a linear, branched, or crosslinked polymer structure.

[0061] The component (F) relating to this disclosure is not particularly limited and known components may be used. Preferred polyorganosiloxanes are polymers containing siloxane units having substituents such as alkyl groups, vinyl groups, and aryl groups, and among these, polyorganosiloxanes having alkyl groups are particularly preferred, and polyorganosiloxanes having methyl groups are more preferred.

[0062] Specific examples of polyorganosiloxanes having methyl groups include, for example, polydimethylsiloxane, polymethylphenylsiloxane, and polymethylhydrogensiloxane. Among these, polydimethylsiloxane is preferred.

[0063] The kinematic viscosity of component (F) relating to this disclosure is not particularly limited, but from the viewpoint of abrasion resistance and scratch resistance, it is preferable that the kinematic viscosity (25°C) specified in JIS Z8803 is 5,000 centistokes (cSt) or higher. Furthermore, from the viewpoint of improving the dispersibility of component (F) in the resulting thermoplastic elastomer composition, resulting in a superior appearance and further improving the quality stability during melt extrusion, it is preferable that the kinematic viscosity of component (F) is less than 3 million cSt. The kinematic viscosity of component (E) is more preferably 10,000 cSt or more and less than 3 million cSt, and even more preferably 50,000 cSt or more and less than 3 million cSt.

[0064] Thermoplastic elastomer composition The thermoplastic elastomer composition of this disclosure contains the propylene polymer (A), the ethylene-α-olefin copolymer (B), a hydrogenated block copolymer (C), a softener (D), and an inorganic filler (E).

[0065] Furthermore, the content of component (D) is 100 to 250 parts by mass, preferably 110 to 230 parts by mass, more preferably 120 to 220 parts by mass, even more preferably 130 to 200 parts by mass, and particularly preferably 140 to 200 parts by mass, per 100 parts by mass of component (A).

[0066] Furthermore, the content of component (E) is 15 to 100 parts by mass, preferably 18 to 90 parts by mass, more preferably 20 to 80 parts by mass, even more preferably 22 to 75 parts by mass, and particularly preferably 25 to 70 parts by mass, per 100 parts by mass of component (A).

[0067] The thermoplastic elastomer composition of this disclosure comprises the above components (A), (B), (C), (D), and (E), and contains components (D) and (E) within the above ranges, thereby suppressing the bleed-out (migration to the surface of the molded article) of component (D) from the thermoplastic elastomer composition and its molded article. The inventors believe the following mechanism can be used to suppress the bleed-out of component (D) from the thermoplastic elastomer composition of this disclosure.

[0068] Generally, if a composition contains an excess of a softening agent (component (D)), the softening agent will bleed out to the surface of the molded product by passing through the amorphous portion of the crystalline polymer, through the amorphous polymer, and along the polymer interface (particle surface), resulting in stickiness on the surface of the molded product. On the other hand, when the composition is in the presence of a predetermined amount of inorganic filler, the softener cannot permeate through the inorganic filler and instead bypasses it to reach the surface of the molded product, thus increasing the number of paths required to reach the surface of the molded product.

[0069] As a result, the amount of softening agent that bleeds onto the surface of the molded product is reduced, and stickiness is suppressed. This effect becomes even more pronounced when the content of the ethylene-α-olefin copolymer (B) or the hydrogenated block copolymer (C) falls within a predetermined range, and the amount of the ethylene-α-olefin copolymer (B) or the hydrogenated block copolymer (C) that crosslinks near the surface of the molded product becomes optimal.

[0070] On the other hand, compositions containing more than 100 parts by mass of component (E) are undesirable for certain applications, such as automobiles, because if a molded article made from such a composition is scratched, component (E) may be exposed, causing the surface of the molded article to whiten, and the mass of the molded article itself increases. The thermoplastic elastomer composition of this disclosure preferably contains 40 to 180 parts by mass, more preferably 70 to 140 parts by mass, of component (B) per 100 parts by mass of component (A). When the content of component (B) is 40 parts by mass or more per 100 parts by mass of component (A), the occurrence of bleed-out is suppressed and a more preferable tactile feel is obtained. Furthermore, when it is 180 parts by mass or less, a more preferable fluidity is obtained.

[0071] Furthermore, the thermoplastic elastomer composition of this disclosure preferably contains 50 to 250 parts by mass, more preferably 70 to 180 parts by mass, of component (C) per 100 parts by mass of component (A). When the content of component (C) is 50 parts by mass or more per 100 parts by mass of component (A), more preferable scratch resistance is obtained, and when it is 250 parts by mass or less, more preferable fluidity is not obtained.

[0072] The thermoplastic elastomer composition of this disclosure can be improved in scratch resistance and abrasion resistance by including the polyorganosiloxane (F) in addition to the above components. If the thermoplastic elastomer composition of this disclosure contains component (F), the content of component (F) is preferably in the range of 2 to 40 parts by mass, more preferably 5 to 30 parts by mass, per 100 parts by mass of component (A). When the content of component (F) is 2 parts by mass or more, the effect of improving the scratch resistance of the resulting thermoplastic elastomer composition is sufficiently exhibited, and when it is 40 parts by mass or less, the dispersibility in the thermoplastic elastomer composition is excellent.

[0073] The thermoplastic elastomer compositions of this disclosure preferably contain an organic peroxide (G) [hereinafter sometimes referred to as "component (G)"] as needed. Component (G) relating to this disclosure acts as a crosslinking initiator, etc., for components (A), (B), and (C), which are components contained in the thermoplastic elastomer composition of this disclosure, by dynamically heat-treating the thermoplastic elastomer composition of this disclosure.

[0074] <Organic peroxide (G)> Specific examples of organic peroxides (G) relating to this disclosure include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)octane, n-butyl-4,4-bis(t-butylperoxy)butane, and n-butyl-4 Peroxyketals such as 4-bis(t-butylperoxy)valerate; dialkylperoxides such as di-t-butylperoxide, dicumylperoxide, t-butylcumylperoxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, α,α'-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexine-3; acetylperoxide, isobutyl Diacyl peroxides such as lyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-trioyl peroxide; t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, di- Examples include peroxyesters such as hydroxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl carbonate, and cumylperoxyoctate; and hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, and 1,1,3,3-tetramethylbutylperoxide.

[0075] Among these components (G), 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyn-3 are preferred from the viewpoint of thermal decomposition temperature and crosslinking performance. The component (G) relating to this disclosure may be used alone or in combination of two or more types.

[0076] If the thermoplastic elastomer composition of this disclosure contains component (G), its content is preferably 1 to 6 parts by mass, more preferably 2 to 4 parts by mass, per 100 parts by mass of component (A), from the viewpoint of moldability. If the thermoplastic elastomer composition of this disclosure contains component (G), it is preferable to use the following crosslinking aid (H) in combination.

[0077] <Crosslinking agent (H)> The crosslinking aid (H) relating to this disclosure includes various known crosslinking aids, specifically monofunctional monomers and polyfunctional monomers. Such crosslinking aids can control the rate of the crosslinking reaction. As monofunctional monomers, for example, radically polymerizable vinyl monomers are preferred, and examples include aromatic vinyl monomers, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, acrylic acid ester monomers, methacrylic acid ester monomers, acrylic acid monomers, methacrylic acid monomers, maleic anhydride monomers, and N-substituted maleimide monomers.

[0078] Specific examples of monofunctional monomers include, for example, styrene, methylstyrene, chloromethylstyrene, hydroxystyrene, tert-butoxystyrene, acetoxystyrene, chlorostyrene, acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, maleic anhydride, methyl maleic anhydride, 1,2-dimethyl maleic anhydride, ethyl maleic anhydride, phenyl maleic anhydride, N-methyl maleimide, N-ethyl maleimide, N-cyclohexyl maleimide, N-lauryl maleimide, and N-cetyl maleimide. Among these, styrene, acrylonitrile, methacrylonitrile, methyl acrylate, maleic anhydride, and N-methyl maleimide are preferred from the viewpoint of ease of reaction and versatility. These monofunctional monomers may be used individually or in combination of two or more.

[0079] A polyfunctional monomer is a monomer having multiple radically polymerizable functional groups, and a monomer having a vinyl group is preferred. The number of functional groups in a polyfunctional monomer is preferably two or three.

[0080] Specific examples of polyfunctional monomers include divinylbenzene, triallyl isocyanurate, triallyl cyanurate, diacetone diacrylamide, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diisopropenylbenzene, p-quinone dioxime, p,p'-dibenzoylquinone dioxime, phenylmaleimide, allyl methacrylate, N,N'-m-phenylenebismaleimide, diallyl phthalate, tetraallyloxyethane, and 1,2-polybutadiene, with divinylbenzene and triallyl isocyanurate being more preferred. These polyfunctional monomers may be used individually or in combination of two or more.

[0081] If the thermoplastic elastomer composition of this disclosure contains a crosslinking aid (H), the amount is 0.1 to 5 parts by mass, preferably 0.2 to 1 part by mass, per 100 parts by mass of component (A).

[0082] <Method for producing thermoplastic elastomer compositions and their physical properties> By dynamically crosslinking the thermoplastic elastomer composition of this disclosure, if the thermoplastic elastomer composition contains components (A), (B), and (C), at least a portion of these components will be crosslinked. When performing dynamic crosslinking, it is preferable to perform dynamic heat treatment in the presence of component (G), or in the presence of both component (G) and component (H). In this disclosure, "dynamically heat-treating" means kneading in a molten state.

[0083] Furthermore, the thermoplastic elastomer composition of this disclosure may be referred to as "Composition 1" before dynamic heat treatment, and as "Composition 2" after dynamic heat treatment.

[0084] The dynamic heat treatment in this disclosure is preferably carried out in a closed apparatus and preferably in an inert gas atmosphere such as nitrogen or carbon dioxide. The heat treatment temperature is in the range of 300°C or less from the melting point of component (A), and is usually 150 to 270°C, preferably 160 to 250°C. The mixing time is usually 1 to 20 minutes, preferably 1 to 10 minutes. The shear force applied is usually 10 to 50,000 s in terms of shear rate. -1 Preferably 100 to 10,000 seconds -1 It is within the range.

[0085] The Shore A hardness (10-second value) of composition 2 (according to the measurement method of JIS K 6253) is preferably 40 to 90, more preferably 45 to 85, and even more preferably 50 to 80. When the Shore A hardness (10-second value) of composition 2 is within the aforementioned range, a molded article with aesthetic appeal such as a pleasant feel and a high-quality appearance, as well as scratch resistance, can be easily formed. The Shore A hardness (10-second value) can be measured specifically by the method described in the following examples.

[0086] The melt flow rate of composition 2 (according to the measurement method of JIS K 7210, 230°C, 1.2 kg load) is preferably 30 to 300 g / 10 min, more preferably 40 to 250 g / 10 min, and even more preferably 55 to 200 g / 10 min, in order to obtain a composition with excellent moldability.

[0087] The thermoplastic elastomer composition of this disclosure may also contain plasticizers and other additives in addition to the above-mentioned component (A), etc. Examples of plasticizers include polyethylene glycol and phthalate esters such as dioctyl phthalate (DOP).

[0088] Other additives include, for example, organic and inorganic pigments such as carbon black, titanium dioxide, or phthalocyanine black; heat stabilizers such as 2,6-di-t-butyl-4-methylphenol and n-octadecyl-3-(3,5'-di-t-butyl-4-hydroxyphenyl)propionate; antioxidants such as trisnonylphenyl phosphite and distearyl pentaerythritol diphosphite; UV absorbers such as 2-(2'-hydroxy-5'methylphenyl)benzotriazole and 2,4-dihydroxybenzophenone; bis-[2,2,6,6-tetramethyl-4-piperidinyl]sebacate, tetramethyl Examples include light stabilizers such as (2,2,6,6-tetramethyl-4-piperidinyl)-1,2,3,4-butanetetracarboxylate; flame retardants such as ammonium polyphosphate, trioctyl phosphate, and magnesium hydroxide; silicone oils such as dimethyl silicone oil and methylphenyl silicone oil; antiblocking agents such as stearic acid amide and erucic acid amide; foaming agents such as sodium bicarbonate and N,N'-dinitrosopentamethylenetetramine; antistatic agents such as palmitate monoglyceride and stearate monoglyceride; and antibacterial agents such as silver ion-supported zeolite and thiosulfite silver complexes.

[0089] Molded body The molded articles relating to this disclosure are not particularly limited as long as they include the thermoplastic elastomer compositions of this disclosure (including compositions 1 and 2), and are molded using any known molding method depending on the application. Examples of molding methods include press molding, injection molding, extrusion molding, calendering, hollow molding, vacuum molding, and compression molding. From the viewpoint of productivity and the ability to easily form complex shapes, injection molded articles formed using injection molding are preferred.

[0090] The thermoplastic elastomer composition disclosed herein has excellent scratch resistance while possessing hardness that satisfies the required performance, and is not particularly limited in its applications. For example, as a molded article, it is suitable for various known applications such as automotive parts, civil engineering and construction materials, electrical and electronic components, sanitary products, films and sheets, foams, and artificial leather, and is particularly suitable for use as an automotive part such as automotive interior parts and as a surface material such as artificial leather.

[0091] <Automotive parts> Examples of automotive parts that can be used with the molded articles of this disclosure include weatherstrips, headliners, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, handbrake grips, shift knob covers, seat adjustment knobs, flapper door seals, wire harness grommets, rack and pinion boots, suspension cover boots, glass guides, inner beltline seals, roof guides, trunk lid seals, molded quarter window gaskets, corner moldings, glass enclosures, hood seals, glass run channels, secondary seals, various gaskets, bumper parts, body panels, side shields, glass run channels, instrument panel surfaces, door surfaces, headliners, weatherstrip materials, hoses, steering wheels, boots, wire harness covers, seat adjuster covers, etc. Among these, the thermoplastic elastomer composition of this disclosure is particularly preferred because it can improve texture and feel.

[0092] <Civil engineering / building materials supplies> Examples of civil engineering and construction materials that can be used with the molded articles relating to this disclosure include civil engineering materials and construction materials such as ground improvement sheets, water intake panels, and noise prevention walls, as well as various gaskets and sheets for civil engineering and construction, waterproofing materials, joint materials, and building window frames. Among these, the thermoplastic elastomer composition relating to this disclosure is particularly preferred because it can improve texture and feel.

[0093] <Electrical and Electronic Components> Examples of electrical and electronic components that can be used in the molded articles relating to this disclosure include, for example, wire insulation materials, connectors, caps, plugs, and other electrical and electronic components. Among these, the thermoplastic elastomer composition relating to this disclosure is particularly preferred because it can improve texture and feel.

[0094] <Household goods> Examples of lifestyle products to which the molded articles relating to this disclosure can be used include sports equipment such as sports shoe soles, ski boots, tennis rackets, ski bindings, and bat grips, as well as miscellaneous goods such as pen grips, toothbrush grips, hairbrushes, fashion belts, various caps, and shoe insoles. Among these, the thermoplastic elastomer composition relating to this disclosure is particularly preferred because it can improve texture and feel.

[0095] <Film / Sheet> Examples of films and sheets that can be used in molded articles according to this disclosure include intravenous fluid bags, medical containers, automotive interior and exterior materials, beverage bottles, clothing cases, food packaging materials, food containers, retort containers, pipes, transparent substrates, sealants, and the like. Among these, the thermoplastic elastomer composition of this disclosure is particularly preferred because it can improve texture and feel.

[0096] <Artificial leather> Examples of artificial leathers that can be used in molded articles according to this disclosure include chair upholstery, bags, school bags, sports shoes such as athletic shoes, marathon shoes, and running shoes, clothing such as jackets and coats, belts, sashes, ribbons, notebook covers, book covers, keychains, pen cases, wallets, business card holders, and pass cases. Among these, the thermoplastic elastomer composition of this disclosure is particularly preferred because it can improve the texture and feel of the leather. [Examples]

[0097] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to these examples.

[0098] The following polymers were used in the examples and comparative examples. [Propylene polymer (A)] As the propylene polymer (A-1), a propylene homopolymer (homoPP) (trade name Sun Allomer® PL400A, manufactured by Sun Allomer Co., Ltd.) with a melt flow rate (MFR): 2.0 g / 10 min at 230°C and a 2.16 kg load was used.

[0099] [Ethylene-α-olefin copolymer (B)] As the ethylene-α-olefin copolymer (B), the following ethylene-α-olefin copolymer was used. (B-1) Ethylene-1-octene copolymer (manufactured by Dow Chemical, trade name "Engage 8842") was used. The copolymer had an ethylene content of 55% by mass and an octene content of 45% by mass. The MFR measured under conditions of temperature: 190°C and load: 2.16 kg was 1.0 g / 10 min. (B-2) Ethylene-propylene-5-ethylidene-2-norbornene (ENB) copolymer was used. The ethylene content of copolymer (B-2) was 70% by mass, and the ENB content was 4.9% by mass.

[0100] [Hydrogenated block copolymer (C)] Hydrogenated styrene-butadiene block copolymer (manufactured by Asahi Kasei Corporation, ToughTec® H1041) was used as the hydrogenated material (C-1) of the block copolymer.

[0101] [Softener (D)] As a softening agent (D-1), paraffin-based oil (manufactured by Idemitsu Kosan Co., Ltd., product name "Diana Process Oil PW-100") was used.

[0102] [Inorganic filler (E)] As an inorganic filler (E-1), calcium carbonate (specific surface area 10,000 cm²) is produced by crushing and classifying limestone. 2 (We used a weight-average particle size of 5.0 μm per g).

[0103] [Polyorganosiloxane (F)] As the polyorganosiloxane (F-1), a masterbatch consisting of 50% by mass of dimethylsiloxane and 50% by mass of polypropylene (manufactured by DuPont-Toray Specialty Materials, trade name "MB50-001") was used.

[0104] [Organic peroxide (G)] As the organic peroxide (G-1), the organic peroxide 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (manufactured by Nippon Oil & Fats Co., Ltd., trade name "Perhexa 25B") was used.

[0105] [Crosslinking agent (H)] Divinylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., trade name "DVB-570"; hereinafter referred to as "DVB") was used as the crosslinking agent (H-1).

[0106] [Example 1] <Manufacturing of thermoplastic elastomer compositions> A twin-screw extruder (30mmφ, L / D=74; manufactured by Kobe Steel, "KTX-30") with an oil inlet in the center of the barrel was used as the extruder. A two-screw screw with mixing sections before and after the inlet was used as the screw. Polymers other than the softener (D-1) listed in Table 1 were mixed together in the amounts (parts by mass) shown in Table 1, and then introduced into a twin-screw extruder (cylinder temperature 200°C) using a quantitative feeder. Subsequently, the amount of (D-1) shown in Table 1 was injected by pump through the inlet in the center of the extruder, and melt-kneading extrusion was performed to obtain a dynamically heat-treated thermoplastic elastomer composition.

[0107] <Manufacturing of injection-molded products> An injection molding machine, model "M150CL-DM" manufactured by Meiki Seisakusho Co., Ltd., was used. The molding conditions were a resin temperature of 220°C and a mold temperature of 40°C. Using a flat mold measuring 15 cm in length and 9 cm in width, with a textured finish, the thermoplastic elastomer composition obtained above was injection molded to create injection molded sample parts. The physical properties of the obtained thermoplastic elastomer compositions and injection-molded samples were evaluated by the following method. The results are shown in Table 1.

[0108] (1) MFR (g / 10 min) The melt flow rate of the thermoplastic elastomer composition obtained above was measured in accordance with JIS K7120 under conditions of 230°C and a 1.2 kg load. Based on the obtained MFR values, the fluidity was evaluated according to the following criteria. ◎:55g / min or more ○: 30g / min or more, less than 55g / min ×: Less than 30g / min

[0109] (2) Shore A hardness measurement A 2 mm thick press sheet was prepared from the thermoplastic elastomer composition obtained above, and a 6 mm thick laminated sheet obtained by stacking three of these press sheets was used as a test specimen. The test specimens obtained above were measured using a Shore A hardness tester in accordance with JIS K6253. After the pressure plate was brought into contact with the test specimen, the value read 10 seconds later was defined as the Shore A hardness (10-second value).

[0110] (3) Scratch resistance The textured surface of the injection-molded sample obtained above was scratched 10 times each in the longitudinal and transverse directions using a pencil-type scratch hardness tester (Erichsen 318 / 318S No.2) with a load of 10N. The scratches in the central grid area were visually observed and evaluated. The evaluation was performed according to the following criteria. ○: There is almost no visible change in appearance due to the damage. ×: Discoloration due to damage is visible.

[0111] (4) Coefficient of kinetic friction (μk) The dynamic friction coefficient of the injection-molded sample was evaluated using the measurement method described below. Using a static / dynamic friction measuring instrument (Trinity Labs, product name "TL201Ts"), the dynamic friction coefficient of the sample surface was measured by bringing a tactile contact into contact with the injection-molded sample under the conditions of a sliding speed of 100 mm / sec, a vertical load of 50 gf, and a sliding distance of 60 mm. Based on the obtained dynamic friction coefficient values, the stickiness (tactile feel) was evaluated according to the following criteria. ◎: 0.60 or less ○: Greater than 0.60 and less than 0.80 ×: 0.80 or less

[0112] [Examples 2 and 3, and Comparative Examples 1 to 5] Except for changing the polymers and their proportions as listed in Table 1, the process was carried out in the same manner as in Example 1, and the compositions were dynamically heat-treated to obtain thermoplastic elastomer compositions. The obtained compositions were evaluated using the method described in Example 1. The results are shown in Table 1.

[0113] [Table 1]

[0114] <Evaluation Results> As shown in Table 1, the injection-molded articles obtained from the thermoplastic elastomer compositions obtained in Examples 1 to 3 exhibit excellent fluidity, tactile feel, and scratch resistance. On the other hand, the thermoplastic elastomer compositions obtained in Comparative Examples 1, 2, and 5 did not yield molded articles with excellent tactile properties. In Comparative Example 3, a molded article with good fluidity was not obtained. In Comparative Example 4, a molded article with excellent scratch resistance was not obtained.

Claims

1. Propylene polymer (A), Ethylene-α-olefin copolymer (B) containing ethylene and α-olefin units having 3 to 20 carbon atoms. Hydrogenated block copolymer (C), Softener (D), and Inorganic filler (E) Includes, The content of the ethylene-α-olefin copolymer (B) is 40 to 180 parts by mass per 100 parts by mass of the propylene polymer (A). The ethylene-α-olefin copolymer (B) contains an ethylene-octene copolymer and contains 70 to 99 mol% of units derived from ethylene (provided that the total amount of units derived from ethylene and units derived from α-olefins having 3 to 20 carbon atoms is 100 mol%). The content of the softening agent (D) is 100 to 250 parts by mass per 100 parts by mass of the propylene polymer (A), The amount of the inorganic filler (E) is 15 to 100 parts by mass per 100 parts by mass of the propylene polymer (A). A thermoplastic elastomer composition characterized by the following features.

2. The thermoplastic elastomer composition according to claim 1, wherein the inorganic filler contains calcium carbonate.

3. The thermoplastic elastomer composition according to claim 1 or 2, wherein the content of the hydrogenated substance (C) in the block copolymer is 50 to 250 parts by mass per 100 parts by mass of the propylene polymer (A).

4. A thermoplastic elastomer composition according to any one of claims 1 to 3, which is dynamically heat-treated.

5. The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein at least a portion of the ethylene-α-olefin copolymer (B) is crosslinked.

6. An injection-molded article comprising the thermoplastic elastomer composition according to any one of claims 1 to 5.

7. Automotive interior part comprising an injection-molded body as described in claim 6.

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