Technical field
[0001]The present invention relates to a thermoplastic elastomer composition and a molded article thereof.
BACKGROUND
[0002]Thermoplastic elastomers, since recycling is lightweight is easy, energy saving, as an elastomer for resource conservation type, particularly automotive parts as a substitute for vulcanized rubber and polyvinyl chloride resins, industrial machinery parts, electric and electronic parts, building materials, etc. widely used.
[0003]
　Among them, olefinic thermoplastic elastomers, since it is an ethylene-propylene-nonconjugated diene copolymer (EPDM) a crystalline polyolefin such as polypropylene as a raw material, as compared with other thermoplastic elastomers, low specific gravity, heat aging resistance, are excellent in durability such as weather resistance, further improvements are required in some applications.
[0004]
　For example, since the vulcanized rubber of EPDM is the main processor, likely contain a softening agent such as oil, it tends to soften, but liquidity and olefinic thermoplastic elastomers are generally tries to softening and bulking a rubber component decrease occurs, the moldability is deteriorated.
[0005]
　Although the thermoplastic elastomer composition obtained by blending an olefin-based thermoplastic elastomer and a styrene-based thermoplastic elastomer has been reported (e.g., Patent Documents 1 and 2), is blended many styrene-based thermoplastic elastomer, sticky liable to occur, also heat resistance because the easily reduced, were blended designed an olefinic thermoplastic elastomer in principal.
[0006]
　Patent Document 3, the type A hardness (instantaneous value) conforming to JIS K6253 75 following the olefin thermoplastic elastomer (A) 35 ~ 65 parts by weight, the type A hardness conforming to JIS K6253 (instantaneous value) 60 or less styrene-based thermoplastic elastomer (B) 65 ~ 35 parts by weight (the total amount of the components (a) and (B) is 100 parts by weight) is a composition comprising a type a hardness conforming to JIS K6253 (instantaneous value) 55 the following thermoplastic elastomer compositions are described.
[0007]
　Using an olefin-based thermoplastic elastomer, a thick portion and a molded thin portion is present, for example when injection molding the airbag cover, locally gloss increases by a sudden change in the fluidity, the appearance is deteriorated It has been known.
[0008]
　Previously it has been attempted to improve the appearance by increasing the thin portion of the molded body, to improve the appearance without changing the thickness of the thin portion has been demanded.
CITATION
Patent Document
[0009]
Patent Document 1: JP 2000-119447 Patent Publication
Patent Document 2: JP 2010-24356 JP
Patent Document 3: WO 2016/039310
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　An object of the present invention, even when manufacturing a molded body thick portion and the thin portion, such as an air bag cover is present in the injection molding, a thermoplastic which can improve the appearance without changing the thickness of the thin portion it is to provide an elastomer composition.
Means for Solving the Problems
[0011]
　The gist of the present invention is as follows.
(1) a polyolefin resin (A) 10 ~ 80 parts by weight, a styrene-based thermoplastic elastomer (B) 10 ~ 80 parts by weight, and at least a part of which is crosslinked rubber (C) 1 ~ 20 parts by weight (component (A) , (B) and the total amount of (C) is a composition comprising 100 parts by weight), the type D hardness (instantaneous value conforming to JIS K6253) is a thermoplastic elastomer composition is 35 or more and 70 or less .
(2) Component (A), (B) and the total amount of 100 parts by weight of (C), a plasticizer (D) from 0 part by mass or more, thermoplastic according to the containing 10 parts by mass or less (1) elastomer composition.
(3) Thermoplastic elastomer according to (1) or (2) including the rubber (C) is an ethylene-alpha-olefin copolymer rubber and / or ethylene-alpha-olefin-nonconjugated polyene copolymer rubber Composition.
(4) the (1) to (3) the thermoplastic elastomer composition molded thermoplastic elastomer molded article obtained according to any one of.
(5) the (1) to (3) the thermoplastic elastomer composition of the thermoplastic elastomer molded article obtained by injection molding according to any one of.
(6) the ratio of the thickest portion (L1) and the thinnest portion of the molded article thickness direction perpendicular to the resin flow direction during molding (L2) (L1 / L2) is 2 to 50 (4) or thermoplastic elastomer molded article according to (5).
(7) the (4) automobile parts comprising a thermoplastic elastomer molded article according to any one of the - (6).
(8) Auto Parts according to (7) is an air bag cover.
The invention's effect
[0012]
　The thermoplastic elastomer composition of the present invention, even when manufacturing a molded body thick portion and the thin portion, such as an air bag cover is present in the injection molding, to improve the appearance without changing the thickness of the thin portion can.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
[1] Figure 1 is a reference view showing a state when creating the thick portion and (3 mm) of the molded body thin portion (0.5 mm) exists.
DESCRIPTION OF THE INVENTION
[0014]
　The following specifically describes the thermoplastic elastomer composition of the present invention.
　The thermoplastic elastomer composition of the present invention, the polyolefin resin (A), the contains a styrene-based thermoplastic elastomer (B), and at least a part of which is crosslinked rubber (C).
[0015]
[Polyolefin Resin (A)]
　The polyolefin resin (A) used in the present invention, preferably include an olefin-based plastic, the case of using an organic peroxide as a crosslinking agent, particularly a peroxide-decomposition type olefin plastic is preferred.
[0016]
　The peroxide-decomposition type olefin plastic, mixed with peroxide, reducing the molecular weight by thermal decomposition by kneading under heating, refers to olefin plastic fluidity of the resin is increased, for example, isotactic polypropylene, a copolymer of propylene with a small amount of another α- olefin, such as propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-4-methyl-1-pentene it can be mentioned copolymers.
[0017]
　Examples of the peroxide-decomposition type olefin plastic include homopolymers or copolymers of α- olefin having 2 to 20 carbon atoms.
[0018]
　The said α- olefins include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1 - pentene, 1-octene, and the like.
[0019]
　Examples Specific examples of (b) peroxide decomposition type olefin plastics, such as (co) polymers are exemplified below.
(1) a propylene homopolymer
(2) propylene and random copolymers with other α- olefin 10 mol% or less
(3) propylene and a block copolymer of the following other α- olefin 30 mole%
( 4) 1-butene homopolymer
(5) 1-butene random copolymer with other α- olefin 10 mol% or less
(6) 4-methyl-1-pentene homopolymer
(7) 4-methyl 1-pentene random copolymer of the following other α- olefin 20 mol%
[0020]
　Polyolefin resin (A) used in the present invention, 230 ° C., a melt flow rate measured under a load 2.16kg (MFR: ISO1133,230 ℃, load 2.16 kg) is usually 5 ~ 150 g / 10 min, preferably it is within the range of 30 ~ 100g / 10 minutes.
[0021]
　In the case of using a phenolic resin-based crosslinking agent as a crosslinking agent can also be the same as the olefinic plastic and the as peroxide decomposition type olefin plastic.
[0022]
　As the polyolefin resin (A) used in the present invention, alpha-olefin and a copolymer of a small amount, for example 10 mole% or less of other polymerizable monomers, such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymers may be used ethylene-methacrylic acid copolymers.
　As the polyolefin resin (A) used in the present invention, polypropylene is particularly preferred.
[0023]
　Examples of commercial products of the polyolefin resin used in the present invention, for example, Prime Polypro (Co., Ltd. Prime Polymer), Mirason (KK Prime Polymer), Suntec (manufactured by Asahi Kasei Chemicals), Novatec (Japan Polypropylene ( Ltd.)), Sumitomo Noblen (manufactured by Sumitomo chemical Co.), Evolue (KK Prime polymer), HI-ZEX (KK Prime polymer), polymethylpentene resin (TPX) (manufactured by Mitsui chemicals Co., Ltd. ), and the like.
[0024]
[Styrene-based thermoplastic elastomer (B)]
　Examples of the styrene-based thermoplastic elastomer used in the present invention (B), preferably, with ethylene · alpha-olefin copolymer composed mainly of alpha-olefins having 3 to 20 carbon atoms a polymer, a styrene / ethylene · alpha-olefin ratio (weight ratio) is usually 5 / 95-75 / 25, preferably 10 / 90-70 / 30.
[0025]
　230 ° C. of the styrene-based thermoplastic elastomer used in the present invention (B), melt flow rate measured under a load 2.16kg (MFR: ISO1133) is generally 0.1 ~ 50 g / 10 min, preferably 1 ~ 40 g / 10 min it is within the range of.
[0026]
　Examples of the styrene-based thermoplastic elastomer used in the present invention (B), specifically, styrene-isoprene block copolymer, styrene-isoprene block copolymer hydrogenated product (SEP), styrene-isoprene-styrene block copolymer polymers of hydrogenated products (SEPS; polystyrene polyethylene / propylene polystyrene block copolymer), styrene-butadiene copolymer, water styrene-butadiene block copolymer hydrogenated product (SEBS; polystyrene polyethylene / butylene-polystyrene include block copolymers) and the like, more specifically, SEPTON [manufactured by Kuraray Co., Ltd.], EARNESTON [manufactured by Kuraray plastics Co., Ltd.], HYBRAR (HYBRAR) [manufactured by Kuraray Co., Ltd.], Clayton (KRATON ), Clayton G [Kraton Polymer Co., Ltd.], Yuropuren SOLT [Versalis Co., Ltd.], JSR-TR, JSR-SIS [JSR (Ltd.), Quinn tack [manufactured by Nippon Zeon Co., Ltd.], Tuftec [Asahi Chemical Industry Co., Ltd.] (more than include the trade name), and the like.
[0027]
　Styrene-based thermoplastic elastomer (B) used in the present invention is preferably a type A hardness conforming to JIS K6253 (instantaneous value) is 96 or less. The type A hardness (instantaneous value), more preferably from 1 to 80.
[0028]
[Crosslinked rubber (C)]
　Examples of the rubber at least part of which is crosslinked used in the present invention (C), not particularly limited, preferably, the peroxide-crosslinkable olefin copolymer rubber and phenolic resin crosslinking olefin copolymer rubbers.
[0029]
　Wherein A peroxide-crosslinkable olefin copolymer rubber, such as ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene rubber, amorphous random elastic mainly composed of olefins such as ethylene-butadiene copolymer rubber a copolymer, is mixed with a peroxide, fluidity crosslinked by kneading with heating means a rubber no longer or flow decreases.
[0030]
　Specific examples of the peroxide-crosslinkable olefin copolymer rubber include the rubbers described below.
(1) Ethylene-alpha-olefin copolymer rubber
[ethylene / alpha-olefin (molar ratio) = about 95 / 5-50 /
50] (2) an ethylene-alpha-olefin-non-conjugated polyene copolymer (preferably , ethylene-alpha-olefin-non-conjugated diene copolymer rubber)
ethylene / alpha-olefin (molar ratio) = about 95 / 5-50 / 50]
[0031]
　The said α- olefins include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1 - pentene, 1-octene, and the like.
[0032]
　Examples nonconjugated diene, specifically, dicyclopentadiene, cyclooctadiene, methylene norbornene (e.g., 5-methylene-2-norbornene), ethylidenenorbornene (e.g. 5-ethylidene-2-norbornene), methyl tetrahydrophthalic indene, 5-vinyl-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, cyclic dienes such as norbornadiene; 1,4-hexadiene, 3-methyl-1 , 4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,4-hexadiene, 6-methyl-1,6-octadiene, 7-methyl 1,6-octadiene, 6-ethyl-1,6-octadiene, 6 Propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7 ethyl-1,6-nonadiene, 6-methyl-1,6-decadiene, 7-methyl-1,6-decadiene, 6-methyl-1,6-undecadiene, chains such as 7-methyl-1,6-octadiene Jo-diene, and the like.
[0033]
　These copolymers Mooney viscosity of the rubber ML 1 + 4 (100 ° C.) is generally 10 to 300, preferably 30-250. Further, iodine value of the case where the non-conjugated diene is copolymerized, preferably 25 or less.
[0034]
　The rubber used in the present invention, in addition to the olefin copolymer rubber, other rubbers, such as styrene - butadiene rubber (SBR), nitrile rubber (NBR), natural rubber (NR), butyl rubber, etc. (IIR) diene rubber, SEBS, etc. polyisobutylene.
[0035]
[Plasticizer (D)]
　The thermoplastic elastomer composition of the present invention optionally can comprise a plasticizer (softener) (D).
[0036]
　The plasticizer (D), can be used plasticizers used in ordinary rubber. Specifically, process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, petroleum-based plasticizers such as vaseline; coal tar, coal tar-based plasticizers such as coal tar pitch; castor oil, linseed oil, rapeseed oil , soybean oil, fatty oil plasticizer coconut oil; tall oil; sub (factice); beeswax, carnauba wax, wax and lanolin; ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, lauric fatty acids and fatty acid salts such as zinc; naphthenate; pine oil, rosin or derivatives thereof; terpene resins, petroleum resins, atactic polypropylene, synthetic polymeric substances such as coumarone-indene resin; dioctyl phthalate, dioctyl adipate, dioctyl sebacate ester plasticizers and the like; micro chestnut Tallinn wax, liquid polybutadiene, modified liquid Poributajin, liquid Thiokol, and hydrocarbon-based synthetic lubricating oils. Among them, petroleum-based plasticizers, are preferably used in particular process oil.
[0037]
　The amount of plasticizer, from the viewpoint of bleed control and coating adhesion, 0 part by weight or more and 10 parts by mass or less.
[0038]
[Olefinic thermoplastic elastomer]
　The polyolefin resin (A) and the rubber at least partially crosslinked (C) may be present in completely or partially crosslinked thermoplastic elastomer of polyolefin.
[0039]
　Of completely or partially crosslinked thermoplastic elastomer of such polyolefin, the partially crosslinked thermoplastic elastomer, for example,
(1) (a) peroxide-crosslinkable olefin copolymer rubber, (b) peroxide decomposition type olefin system plastic (polyolefin resin (a)) and consisting of a mixture, or (a) a peroxide-crosslinkable olefin copolymer rubber, (b) and the peroxide-decomposition type olefin plastic (polyolefin resin (a)), (c) peroxide non-crosslinked type rubbery substance and / or (d) a mixture comprising a mineral oil-based softening agent, obtained by dynamically heat-treated in the presence of an organic peroxide, partially crosslinked thermoplastic elastomer,
(2) (a) and the peroxide-crosslinkable olefin copolymer rubber, (b) peroxide decomposition Olefinic plastic (polyolefin resin (A)), the (c) peroxide non-crosslinked rubber-like material and / or (d) a mixture of a mineral oil-based softening agent, an organic peroxide (or phenolic resin-based crosslinking agent) the rubber composition is crosslinked, obtained by dynamically heat-treated in the presence of, crosslinked (e) the polyolefin resin (a) was allowed to uniformly mixed, partially crosslinked thermoplastic elastomer (and completely thermoplastic elastomer), and the like.
[0040]
　Mixed with said (c) peroxide non-crosslinked rubber-like material, for example polyisobutylene, butyl rubber, atactic polypropylene, propylene content as such at least 50 mol% propylene · alpha-olefin copolymer rubber, a peroxide was not crosslinked be kneaded under heating, the flowability refers to gum hydrocarbon does not decrease.
[0041]
　Wherein A of (d) a mineral oil softening agent, when rolling ordinary rubber, weakening the intermolecular action force of the rubber, as well as to facilitate processing, or aid carbon black, a dispersion such as white carbon, or flexibility and allowed reducing the hardness of vulcanized rubber, elastic in petroleum fractions having a high boiling point which are used for the purpose of increasing the paraffinic, naphthenic, are distinguished in the aromatic system, or the like. Mineral oil softening agents such as paraffinic process oils, naphthenic process oils and the like.
[0042]
　In preferred olefinic thermoplastic elastomer used in the present invention, (b) an olefinic plastic and (a) the mass mixing ratio of the olefin copolymer rubber ((b) / (a)) is usually 90/10 ~ 10/90, preferably in the range of 70 / 30-15 / 85.
[0043]
　Further, as the rubber, when used in combination the olefin copolymer rubber and other rubber, other rubbers, the total amount of 100 parts by mass of the peroxide decomposition type olefin plastics and rubber, generally 40 parts by mass or less, preferably in a proportion of 5 to 20 parts by weight.
[0044]
　Olefinic thermoplastic elastomers preferably used in the present invention comprises a crystalline polypropylene, an ethylene-alpha-olefin copolymer rubber or ethylene-alpha-olefin-non-conjugated diene copolymer rubber, an olefinic thermoplastic elastomer present in a state where they are partially crosslinked in the middle, and an olefinic thermoplastic elastomer mass compounding ratio of the crystalline polypropylene and the rubber (crystalline polypropylene / rubber) is in the range of 70 / 30-10 / 90 it is.
[0045]
　More specific examples of the olefin thermoplastic elastomer preferably used in the present invention, the rubber comprising an ethylene-propylene copolymer rubber or ethylene-propylene-diene copolymer rubber (a-1) 30 ~ 90 parts by weight total amount is set to 100 parts by weight of component (a-1) and (b-1)] and the rubber other than the rubber (a-1) a crystalline polypropylene (b-1) 70 ~ 10 parts by weight and (c) and / or mineral oil type softening agent (d) is a mixture consisting of 5 to 150 parts by mass, obtained by dynamically heat-treated in the presence of an organic peroxide, said rubber (a-1) is partially include thermoplastic elastomers crosslinked.
[0046]
　Examples of the organic peroxides, specifically, dicumyl peroxide, di -tert- butyl peroxide, 2,5-dimethyl-2,5-di - (tert-butylperoxy) hexane, 2,5-dimethyl-2, 5-di - (tert- butylperoxy) hexyne-3,1,3-bis (tert- butylperoxy-isopropyl) benzene, 1,1-bis (tert- butylperoxy) -3,3,5-trimethylcyclohexane, n - butyl-4,4-bis (tert- butylperoxy) valerate, benzoyl peroxide, p- chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert- butyl peroxybenzoate, tert- butylperoxy isopropyl carbonate, diacetyl peroxide Lauroyl peroxide, etc. tert- butyl cumyl peroxide.
[0047]
　Of these, odor, in terms of scorch stability, 2,5-dimethyl-2,5-di - (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di - (tert-butyl peroxy) hexyne 3,1,3-bis (tert- butylperoxy-isopropyl) benzene, 1,1-bis (tert- butylperoxy) -3,3,5-trimethylcyclohexane, n- butyl-4,4-bis (tert- butylperoxy) valerate are preferred, 2,5-dimethyl-2,5-di - (tert- butylperoxy) hexane, 1,3-bis (tert- butylperoxy-isopropyl) benzene is most preferred.
[0048]
　Organic peroxides, based on the total amount of 100 parts by mass of the crystalline polyolefin and rubber, generally 0.01 to 5 parts by weight, preferably used in a ratio of 0.05 to 3 parts by weight.
[0049]
　Upon crosslinking treatment by the organic peroxide, sulfur, p- quinone dioxime, p, p'-dibenzoyl quinone dioxime, N- methyl -N, 4-di-nitroso aniline, nitroso benzene, diphenyl guanidine, trimethylol propane, N , N'-m-phenylene maleimide, divinylbenzene, triallyl cyanurate, crosslinking aids such as triallyl isocyanurate or ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, it can be blended polyfunctional methacrylate monomers such as allyl methacrylate, vinyl butyrate, and polyfunctional vinyl monomers such as vinyl stearate.
[0050]
　The use of compounds as described above, uniform and mild crosslinking reaction can be expected. Particularly, in the present invention, divinylbenzene is most preferable. Divinyl benzene, easy to handle, said has good compatibility with the crystalline polyolefin and the rubber which is a main component of the crosslinked treated and has a function of solubilizing the organic peroxide, organic peroxide dispersant to act as, a homogeneous crosslinking effect by heat treatment, take olefinic thermoplastic elastomer balance between fluidity and physical properties is obtained.
[0051]
　The olefinic thermoplastic elastomer used in the present invention, if prepared using phenolic resin-based crosslinking agent as the crosslinking agent, the polyolefin resin (A) and uncrosslinked rubber (C), such as ethylene-alpha-olefin-nonconjugated it is preferable to dynamically cross-link the polyene copolymer with phenol resin-based crosslinking agent. In the present invention, the term "dynamic crosslinking" refers to crosslinking while the shearing force is added to the mixture.
[0052]
　The phenol resin-based crosslinking agent, a halogenated phenolic resin crosslinking agent. The phenol resin-based crosslinking agent, a resol resin a is alkyl substituted phenols or unsubstituted phenols condensed with aldehydes in an alkaline medium, are preferably prepared condensation with formaldehyde, or by condensation of bifunctional phenols dialcohols it is also preferred. Alkyl-substituted bodies of alkyl substituted phenols 1 to about 10 carbon atoms are preferred. Furthermore 1 to dimethylol phenol or phenolic resin substituted with an alkyl group having about 10 carbon atoms in the p- position being preferred. Phenol resin-based curing resin is typically a thermally crosslinkable resin, also referred to as phenolic resin crosslinking agent, or a phenolic resin.
[0053]
　Examples of the phenolic resin-based curing resin (phenol resin-based crosslinking agent), there can be mentioned the compounds represented by the following general formula (I).
[Chemical formula 1]

　(In the formula, Q is, -CH 2 - and -CH 2 -O-CH 2 - is a bivalent group selected from the group consisting of, m is 0 or 1 to 20 positive integer of There, R 'is an organic group.)
[0054]
　Preferably, Q is a divalent radical -CH 2 -O-CH 2 - and is, m is 0 or a positive integer of 1 to 10, R 'is an organic radical having less than 20 carbon atoms. More preferably, m is 0 or a positive integer of 1 to 5, R 'is an organic group having 4 to 12 carbon atoms. Specifically alkylphenol-formaldehyde resins, methylolated alkylphenol resins, halogenated alkylphenol resin and the like, preferably a halogenated alkylphenol resin, more preferably, those which the terminal hydroxyl group was brominated.
[0055]
[Formula 2]

(wherein, n an integer of 0 to 10, R is a saturated hydrocarbon group having 1 to 15 carbon atoms.)
[0056]
　As a product example of the phenolic curing resin, Tackirol (TM) 201 (alkylphenol formaldehyde resin, Taoka Chemical Co., Ltd.), Tackirol (TM) 250-I (brominated 4% of a brominated alkylphenol formaldehyde resins, Taoka Chemical Co., Ltd.), Tackirol (TM) 250-III (brominated alkylphenol formaldehyde resin, Taoka Chemical Co., Ltd.), PR-4507 (Gun Ei Chemical Industry Co., Ltd.), Vulkaresat510E (Hoechst Co., Ltd.), Vulkaresat532E (Hoechst Co., Ltd.), made Vulkaresen E (Hoechst Corporation), Vulkaresen105E (Hoechst Co., Ltd.), Vulkaresen130E (Hoechst Co., Ltd. ), Vulkaresol315E made (Hoechst Co., Ltd.), made Amberol ST 137X (Rohm & Haas Co., Ltd.), SUMILITERESIN (registered trademark) PR-22193 (Sumitomo Durez Co.), Symphorm-C-100 (manufactured by Anchor Chem. Companies) , Symphorm-C-1001 (manufactured by Anchor Chem. companies), Tamanol (manufactured by Arakawa chemical Co.) (registered trademark) 531, Schenectady SP1059 (manufactured by Schenectady Chem. companies), Schenectady SP1045 (SchenectadyChem. companies made), CRR -0803 (U.C.C Co., Ltd.), Schenectady SP1055F (Schenectady Chem. companies made, brominated alkyl phenol formaldehyde tree ), Schenectady SP1056 (manufactured by Schenectady Chem. Companies), CRM-0803 (Showa Union Synthesis Co., Ltd.), Vulkadur A (Bayer Corporation). Among them, halogenated phenol resin-based crosslinking agent is preferred, Tackirol (TM) 250-I, Tackirol (TM) 250-III, Schenectady
[0057]
　Further, specific examples of crosslinking by thermoplastic vulcanizates of phenolic resins are described in U.S. Patent No. 4,311,628, U.S. Pat. No. 2,972,600 and U.S. Pat. No. 3,287,440 described, it is possible to use these techniques in the present invention.
[0058]
　No. 4,311,628, phenolic curing resin (phenolic curing resin) and a phenol type vulcanizing agent system consisting of a vulcanization-activating agent (cure activator) (phenolic curative system ) is disclosed. Basic components of the system are substituted phenol in an alkaline medium (e.g., halogen substituted phenol, C 1 -C 2 alkyl substituted phenol) or unsubstituted phenol with an aldehyde, preferably either by condensation with formaldehyde, or bifunctional phenol dialcohols (preferably, the para position is C 5 -C 10A phenolic resin-based crosslinking agent produced by the condensation of alkyl dimethylol phenols substituted in the group). Alkyl-substituted phenol resin-based crosslinking agent which is halogenated is prepared by halogenation of alkyl substituted phenol resin-based crosslinking agent, it is particularly suitable. Methylol phenolic curing resin, phenolic resin crosslinking agent consisting of a halogen donor and metal compound can be particularly recommended, details described in each of U.S. Patent Nos. 3,287,440 and Nos. No. 3,709,840 It is. Non-halogenated phenolic resin crosslinking agent, simultaneously with the halogen donor, it is preferably used in conjunction with a hydrogen halide scavenger. Usually, a halogenated phenolic resin crosslinking agent, preferably, bromination contains from 2 to 10 wt% brominated phenolic resin crosslinking agent does not require a halogen donor, for example iron oxide, titanium oxide, magnesium, magnesium silicate, silicon dioxide and zinc oxide are preferably used as hydrogen halide scavenger such as metal oxides such as zinc oxide at the same time. Hydrogen halide scavenger such as these zinc oxide per 100 parts by mass of the phenolic resin crosslinking agent is used normally 1 to 20 parts by weight. The presence of such scavengers promotes a crosslinking action phenolic resin crosslinking agent, in the case of a rubber not easily vulcanized with a phenolic resin crosslinking agent, it is desirable to share a halogen donor and zinc oxide . Are described in these applications are the U.S. Patent No. 2,972,600 No. and the 3,093,613 in vulcanizing systems using preparation and zinc oxide halogenated phenolic curing resin , the disclosure of the U.S. Patent No. 3,287,440 No. and the first 3,709, With the disclosure of 840 Pat intended to incorporate by reference herein. Examples of suitable halogen donor, for example, stannous chloride, ferric chloride, or chlorinated paraffin, chlorinated polyethylene, halogen-donating heavy, such as chlorosulfonated polyethylene and polychlorobutadiene (neoprene rubber) coalescence, and the like. The term "vulcanization accelerator" as used herein refers to any substance that substantially increases the crosslinking efficiency of the phenolic resin-based crosslinking agent, and includes a metal oxide and a halogen donor, these alone or in combination are used. For a more detailed of the phenol-based vulcanizing agent system, see "Vulcanization and Vulcanizing Agents" (W. Hoffman, Palmerton Publishing Company). Suitable phenolic resins based crosslinking agent and a brominated phenolic resin crosslinking agent may be obtained commercially, for example, such crosslinking agents Schenectady Chemicals, trade name from Inc. "SP-1045", "CRJ-352 ", it can be purchased as" SP-1055F "and" SP-1056 ". Similar effects on the equivalent of the phenolic resin-based crosslinking agent may also be obtained from other suppliers. Product name from the "SP-1045", can be purchased as a "CRJ-352", "SP-1055F" and "SP-1056". Similar effects on the equivalent of the phenolic resin-based crosslinking agent may also be obtained from other suppliers. Product name from the "SP-1045", can be purchased as a "CRJ-352", "SP-1055F" and "SP-1056". Similar effects on the equivalent of the phenolic resin-based crosslinking agent may also be obtained from other suppliers.
[0059]
　Phenol resin-based crosslinking agent, for the generation of decomposition products is low, it is suitable vulcanizing agents from the viewpoint of fogging prevention. Phenol resin-based crosslinking agent is used in an amount sufficient to achieve essentially complete vulcanization of the rubber.
[0060]
　Phenolic resin crosslinking agent, the ethylene-alpha-olefin-nonconjugated polyene copolymer 100 parts by weight, usually 0.1 to 20 parts by weight, is used in such an amount that preferably is 1 to 10 parts by weight . By the amount of phenolic resin crosslinking agent in the range, the composition having excellent moldability can be obtained and, the resulting molded article, a high strength, has excellent oil resistance, sufficient having heat resistance and mechanical properties.
[0061]
　In the present invention, when the dynamic crosslinking with phenolic resin crosslinking agent, sulfur, p- quinone dioxime, p, p'-dibenzoyl quinone dioxime, N- methyl -N, 4-di-nitroso aniline, nitroso benzene, diphenylguanidine, trimethylolpropane -N, peroxy crosslinking aids such as N'-m-phenylene maleimide, divinylbenzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane can be formulated trimethacrylate, polyfunctional methacrylate monomers such as allyl methacrylate, vinyl butyrate, and aids such as polyfunctional vinyl monomers such as vinyl stearate.
[0062]
　The use of the aid, uniform and mild crosslinking reaction can be expected. As the aid, divinylbenzene is preferable. Divinyl benzene, easy to handle, are compatible with the crystalline olefin polymer contained as a main component in the thermoplastic elastomer composition and the ethylene-alpha-olefin-nonconjugated polyene copolymer is good, and a phenol resin has a function of solubilizing the system crosslinking agent, to serve as a dispersing agent for phenolic resin-based crosslinking agent, a homogeneous crosslinking effect by heat treatment, balanced thermoplastic elastomer composition of the balance between fluidity and physical properties is obtained .
[0063]
　The aid, the ethylene-alpha-olefin-nonconjugated polyene copolymer 100 parts by weight of normally less than 2 parts by mass, is used in such an amount that preferably is 0.3 to 1 part by mass.
[0064]
　In order to accelerate the decomposition of the phenolic resin-based crosslinking agent may be used dispersing aid. The decomposition accelerator, triethylamine, tributylamine, tertiary amines such as 2,4,6-tri (dimethylamino) phenol; aluminum, cobalt, vanadium, copper, calcium, zirconium, manganese, magnesium, lead, mercury or the like, naphthenic acid and various metals (e.g., Pb, Co, Mn, Ca, Cu, Ni, Fe, Zn, rare earth) naphthenic acid salts with.
[0065]
　Wherein the crosslinking aid or the polyfunctional vinyl monomer such as, with respect to said object to be crosslinked treated whole 100 parts by weight, used in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight It is preferred. When the amount of the crosslinking assistant or polyfunctional vinyl monomer is more than 5 parts by mass, when the amount of the organic peroxide is large, the crosslinking reaction proceeds too rapidly, thermoplastic elastomer obtained is flowable inferior, whereas, if the amount of the organic peroxide is small, crosslinking auxiliary and polyfunctional vinyl monomer, remains as unreacted monomer in the thermoplastic elastomer, thermoplastic elastomer, thermally during processing molding changes in the physical properties or caused by history. Therefore, crosslinking auxiliary and polyfunctional vinyl monomer should not be excessively blended.
[0066]
　It said "dynamically heat treating" refers to kneading in a molten state the components as described above. The kneading apparatus, conventionally known kneading apparatus, for example, open type mixing roll, non-open type Banbury mixer, extruder, kneader, continuous mixer or the like is used. Of these, non-open type kneading apparatus is preferable, kneading, a nitrogen gas, is preferably carried out in an atmosphere of an inert gas such as carbon dioxide.
[0067]
　Further, the kneading is carried out at a temperature at which the half-life of the organic peroxide used is less than 1 minute is desirable. The kneading temperature is generally 0.99 ~ 280 ° C., preferably 170 ~ 270 ° C., the kneading time is usually 0.5 to 20 minutes, preferably 1 to 10 minutes. Further, the shear force applied is typically a shear rate, 10 ~ 50,000Sec -1 , preferably 100 ~ 10,000Sec -1 is determined in the range of.
[0068]
　Incidentally, fully crosslinked olefin-based thermoplastic elastomer, said (1), prepared by varying the olefinic amount of the organic peroxide according to the process for the preparation of thermoplastic elastomers, conditions such as kneading time (2) can do.
[0069]
　Olefinic thermoplastic elastomer used in the present invention, the type A hardness (instantaneous value) that conforms to JIS K6253 is preferably 60 or more. The type A hardness (instantaneous value) is usually 1-98, preferably 60-98, more preferably 70-98, particularly preferably 80-98.
[0070]
　Olefinic thermoplastic elastomer used in the present invention, 230 ° C., a melt flow rate measured under a load 2.16kg (MFR: ISO1133,230 ℃, load 2.16 kg) is usually 0.1 ~ 100 g / 10 min, preferably it is within the range of 1 ~ 100g / 10 minutes.
[0071]
[Thermoplastic elastomer composition]
　The thermoplastic elastomer composition of the present invention, the polyolefin resin (A) 10 ~ 80 parts by weight, a styrene-based thermoplastic elastomer (B) 10 ~ 80 parts by weight, and at least a part of which is crosslinked rubber (C) 1 ~ 20 parts by weight (component (a), (B) and (the total amount of C) is 100 parts by weight) include, preferably a polyolefin tree · BR> weir IA) 20 ~ 70 parts by weight the total amount of the styrene-based thermoplastic elastomer (B) 20 ~ 70 parts by weight, and at least a part of which is crosslinked rubber (C) 1 ~ 15 parts by weight (component (a), (B) and (C) is 100 comprises a parts by weight), more preferably the polyolefin resin (a) 30 ~ 60 parts by weight, a styrene-based thermoplastic elastomer (B) 30 ~ 60 parts by weight, and at least a part of which is crosslinked rubber (C) 1-10 parts by weight containing (components (A), (the total amount of B) and (C) is 100 parts by weight). Component (A) in a proportion of the, by blending (B) and (C), the molded body thick portion and the thin portion, such as an air bag cover is present even when manufactured by injection molding, thin-wall portion it is possible to improve the appearance without changing the thickness of. For example, the ratio of the thickest portion (L1) and the thinnest portion of the molded article thickness direction perpendicular to the resin flow direction during molding (L2) (L1 / L2) is usually 2 or more, preferably 50 or less (the lower limit value 3 or more, more preferably 5 or more, and is preferably the upper limit is 20 or less, even when produced in an injection molding a molded body is more preferably 10 or less), to improve the appearance without changing the thickness of the thin portion be able to.
[0072]
　When the proportion of the polyolefin resin (A) is less than 10 parts by mass, it becomes difficult not obtained sufficient rigidity molding, while when it exceeds 80 parts by mass, the appearance improving effect of surface gloss is obtained up small Become. When the proportion of the styrene-based thermoplastic elastomer (B) is less than 10 parts by mass, the appearance improving effect of surface gloss is significantly improved expected decreases, while when it exceeds 80 parts by mass, sufficient rigidity obtained It is molded it is difficult not. When the proportion of the crosslinked rubber (C) is more than or 20 parts by less than 1 part by weight, easily noticeable appearance differences thick portion and a thin portion, resulting appearance improving effect is reduced.
[0073]
　The thermoplastic elastomer composition of the present invention, the type D hardness (instantaneous value) that conforms to JIS K6253 is 35 or more and 70 or less. Wherein the type D hardness (instantaneous value) is less than 35, it is difficult without sufficient rigidity is obtained molded as a molded article, while when it exceeds 70, appearance surface gloss is significantly improved expected improvement effect is reduced.
[0074]
　The type D hardness (instantaneous value) 35-70 of the thermoplastic elastomer composition of the present invention, preferably from 40 to 70, more preferably 45-70.
[0075]
　The thermoplastic elastomer composition of the present invention, from the viewpoint of moldability, it is preferred that the type A hardness (instantaneous value) that conforms to JIS K6253 is 60 or more, more preferably 70-98, 85-98 still more preferably.
[0076]
　The thermoplastic elastomer composition of the present invention, the polyolefin resin (A), the styrene-based thermoplastic elastomer (B) and at least a part of which is crosslinked rubber (C), if necessary, a rubber softener (e.g., the of (d) a mineral oil softening agent), an ethylene · alpha-olefin copolymer, can be further post-melt-kneading other components, prepared by employing the method of granulation or pulverization.
[0077]
　The thermoplastic elastomer composition of the present invention, the content from the viewpoint of fluidity modifier, a portion of the polyolefin resin (A), the the uncrosslinked rubber (C), an organic peroxide, if necessary, other components mixture dynamically heat treated to, after creating the olefinic thermoplastic elastomer containing a partially or fully crosslinked rubber (C), and the remainder of the polyolefin resin (a), the styrene-based thermoplastic elastomer (B ) and, if necessary, after melting and kneading other components it is preferably produced by a method of granulation or pulverization.
[0078]
　As the kneading apparatus, a mixing roll and an intensive mixer (e.g., Banbury mixer, kneader), it can be used a uniaxial or biaxial extruder or the like, a non-open type apparatus is preferred.
[0079]
　The thermoplastic elastomer composition of the present invention has high flowability, it is preferred to mold the shaped body from the injection molding process. Further, an injection mold is injected the thermoplastic elastomer composition into the cavity of the mold closed state, after the injection is completed, the mobile while maintaining contact with the mold wall surface by expansion of the resin by foaming gas moving the, molding is stopped at the reference thickness position set in advance the mobile. After mold cooling has been completed, retracting the movable die is obtained by taking the product, it is possible to injection foam molding by core back. The resin temperature during the injection is preferably in the range of 160 ~ 260 ° C..
[0080]
　Molding of the present invention, according to Embodiments 1 to 3 below, it may be laminated with an olefin-based resin substrate.
[0081]
　
forming method: extrusion from calendering or T-die
laminating method: sequential method is laminated on the base layer a surface layer after the sheet made of a polyolefin base layer and foam molding, or, T-die extrusion in the case of molding the simultaneous multi-layer extrusion.
[0082]
　
molding method: multi-layer extrusion
lamination method: simultaneous multi-layer extrusion of the polyolefin substrate layer and the surface layer.
[0083]
　
forming method: successive or simultaneous injection molding
lamination method: a polyolefin substrate layer after injection foam, injecting a thermoplastic elastomer composition which is the surface layer, the sequential injection molding of stacking in a mold, or, simultaneously injecting a substrate layer and a surface layer by so-called sandwich molding, simultaneous method of molding a multilayer part.
[0084]
[Use of the thermoplastic elastomer composition]
　The thermoplastic elastomer composition of the present invention, various known molding method, specifically, for example, extrusion molding, press molding, injection molding, calender molding, hollow molding building various the molding method may be a thermoplastic elastomer molding. Further, the molded like sheets obtained in the molding method thereof capable of secondary processing by the thermal molding.
[0085]
　Thermoplastic elastomer molded article of the present invention is not particularly limited its intended use, for example, automobile parts, civil engineering and building materials goods, electric and electronic parts, sanitary goods, a variety known applications such as films and sheets it is preferred.
[0086]
　The thermoplastic elastomer composition of the present invention, even when manufacturing a molded body thick portion and the thin portion is present in the injection molding, it is possible to improve the appearance without changing the thickness of the thin portion, the airbag the molded body thick portion and a thin portion such as a cover is present is optimal for the production by injection molding.
[0087]
　
　The automobile parts may be used in the thermoplastic elastomer molded article of the present invention, automotive interior parts, there are automotive exterior parts, e.g., weatherstrip material, bumper molding, side molding, air spoiler, air duct hoses, wire harness grommet, rack and pinion boots, suspension cover boots, glass guide, inner belt line seal, corner moldings, glass encapsulation, hood seal, glass run channels, secondary seal, various packings, hose, illustrating the air bag cover, etc. can, inter alia the thermoplastic elastomer composition of the present invention is excellent in injection molding or injection foam moldability, a molded article obtained by injection molding or injection foam molding is particularly preferred.
[0088]
　
　As the civil engineering and building materials goods that may be used in the thermoplastic elastomer molded article of the present invention, for example, soil improvement sheet, clean water plates, construction materials and building materials such as anti-noise, for civil engineering and construction Various gaskets and sheets, water stopping material, joint fillers, etc. architectural window frames can be exemplified. Among these thermoplastic elastomer composition of the present invention is excellent in injection molding or injection foam moldability, a molded article obtained by injection molding or injection foam molding is particularly preferred.
[0089]
　
　The thermal electric and electronic components may be used in the thermoplastic elastomer molded article of the present invention, for example, it can be exemplified wire covering material, connector, cap, and electrical and electronic parts such as a plug, among others present invention of the thermoplastic elastomer composition is excellent in injection molding or injection foam moldability, a molded article obtained by injection molding or injection foam molding is particularly preferred.
[0090]
　
　as hygiene articles may be used in the thermoplastic elastomer molded article of the present invention, for example catamenial, disposable diapers, can be exemplified such as sanitary goods such as a toothbrush grip, inter alia the thermoplastic elastomer composition of the present invention , it is excellent in injection molding or injection foam moldability, a molded article obtained by injection molding or injection foam molding is particularly preferred.
[0091]
　
　The film sheets may be used in the thermoplastic elastomer molded article of the present invention, for example, infusion bags, medical containers, automobile interior and exterior materials, beverage bottles, wardrobe, food packaging materials, food containers, retort containers, pipes, transparent substrate, can be exemplified such as sealants, among them the thermoplastic elastomer composition of the present invention is excellent in injection molding or injection foam moldability, a molded article obtained by injection molding or injection foam molding is particularly preferred.
[0092]
　
　Other applications that may be used in the thermoplastic elastomer molded article of the present invention, for example, shoe soles, footwear such as sandals, swim fin, water glasses, golf club grips, baseball bat grips, etc. leisure goods, gaskets , waterproof cloth, belt, garden hose, stair-slip tape, such as anti-slip tape of logistics pallet can be exemplified.
[0093]
　As applications that may be used in the thermoplastic elastomer molded article of the present invention is not limited to the applications, it may be used in various applications.
[0094]
　This specification includes the contents as disclosed in the specification and drawings of Japanese Patent Application No. 2017-066222 which is a priority document of the present application.
Example
[0095]
　Hereinafter, the present invention will be described more specifically based on Examples, the present invention is not intended to be limited to these Examples.
[0096]
　The measurement methods and evaluation methods of implementation and physical properties in the following is as follows.
(1) Tensile strength test
　in compliance with JIS K6251, a test piece by injection molding (JIS 3 dumbbell, thickness 2 mm) creates a tensile strength (TB) (unit: MPa) and elongation at break (EB) ( unit:%) were measured at a tensile rate of 500 mm / min in an atmosphere of 23 ° C. or -35 ° C..
(2) Melt flow rate
　(MFR) conforming to ISO 1133 (or ASTM D1238), 230 ℃, was measured at 2.16kg load.
(3) Shore hardness measurement
(a) Shore D hardness
　in conformity with ISO7619 (JIS K6253), using an injection molding angle plate having a thickness of 3mm, a laminated sheet having a thickness of 6 mm (2-ply thickness 3mm pieces) It was measured by a Shore D hardness tester using. The Shore D hardness was determined the instantaneous values.
(B) Shore A hardness
　in compliance with JIS K6253, using an injection molding angle plate having a thickness of 2mm, were measured by the Shore A hardness tester using a laminated sheet having a thickness of 6 mm (3 ply thickness 2mm pieces) . For Shore A hardness was determined the instantaneous values.
(4) Appearance
　by injection molding, the tear line to create a shaped body thick portion as shown in FIG. 1 (3 mm) and thin portions (0.5 mm) is present, occurs in the portion where there is a thickness difference after molding was observed by the naked eye gross change in (the cover will tear line when the airbag operation) unit, and evaluated according to the following criteria.
　1. The difference is remarkable, 2. There is a slight but whether the difference between, 3. I can not tell the difference
[0097]
[Examples 1 and 2 and Comparative Example 1]

The (A) polyolefin resin was used as follows.
Block polypropylene (PP-1)
a melt flow rate 10 g / 10 min (230 ° C., 2.16 kg load)
of ethylene unit content 14 mol%
block of polypropylene (PP-2)
Melt flow rate (ISO 1133 ° C., 2.16 kg load) 50 g / 10 min
density (ISO1183) 0.90 g / cm 3
tensile modulus (ISO 527) 1450 MPa
Charpy impact strength (ISO179,23 ° C.) 10 kJ / m 2
heat deflection temperature (ISO75,1.8MPa) 55 ℃
[0098]
The (B) a styrene-based thermoplastic elastomer was used as follows.
Styrene / ethylene-butylene copolymer (B-1)
Melt flow rate (ISO 1133 ° C., 2.16 kg load) 20 g / 10 min
A hardness (ISO7619) 70
Density (ISO1183) 0.89 g / cm 3
styrene / ethylene butylene ratio (weight ratio) = 20/80
[0099]
The (C) Rubber The following were used.
Oil-extended ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (C-1) an ethylene unit content 78 mol%
iodine value 13
intrinsic viscosity [η] 3.4dl / g
oil extended amount: rubber 100 parts by weight against it, a plasticizer (Diana process oil PW-380, manufactured by Idemitsu Kosan) and 40 parts by mass
[0100]
(Example 1)
　oil-extended ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (C-1) and 50 parts by weight, block polypropylene (PP-1) and 50 parts by weight, an organic peroxide as a crosslinking agent ( Perhexa 25B, manufactured by NOF and Co.) 0.3 part by mass, divinylbenzene 0.3 part by weight as a crosslinking agent, manufactured by phenolic antioxidants (Irganox 1010, BASF Corp. as an antioxidant) thoroughly mixed with 0.1 part by weight in a Henschel mixer and extrusion kneaded under the following conditions.
Extruder (No. KTX-46, Kobe Steel, Ltd., cylinder temperature: C1 ~ C2 120 ℃, C3 ~ C4 140 ℃, C5 ~ C14 200 ℃, die temperature: 200 ° C., a screw rotation speed: 400 rpm, extrusion rate : 80kg / h)
[0101]
　Obtained by the process, partially or fully crosslinked thermoplastic elastomer composition (alpha) (melt flow rate (230 ° C., 2.16 kg load) 25 g / 10 min, durometer D39) with respect to 100 parts by weight , a block polypropylene (PP-2) 600 parts by weight of a styrene / ethylene-butylene copolymer (B-1) 550 parts by weight of phenolic antioxidant (Irganox 1010, manufactured by BASF (Ltd.)) 0.1 and parts by weight, were mixed thoroughly in a Henschel mixer and kneaded under the following conditions using an extruder.
[0102]
　Thus, physical properties were evaluated to obtain a composition mass ratio of the polyolefin resin (A) / styrene-based thermoplastic elastomer (B) / rubber (C) is 52.6 / 44.5 / 2.9.
[0103]
(Kneading conditions)
Extruder: No. KTX-46, Kobe Steel Co., Ltd.
Cylinder temperature: C1 ~ C2 120 ℃, C3 ~ C4 140 ℃, C5 ~ C14 200 ℃
die temperature: 200 ° C.
Screw rotation speed: 400 rpm
extrusion rate : 80kg / h
[0104]
(Example 2)
　Polyolefin resin (A) (block polypropylene (PP-1), block polypropylene (PP-2)), a styrene / ethylene-butylene copolymer (B-1) and ethylene-propylene-5-ethylidene - except for changing the mass ratio of 2-norbornene copolymer rubber (C-1) a, as shown in Table 1, in the same manner as in example 1, to obtain a thermoplastic elastomer composition.
[0105]
(Comparative Example 1)
　a rubber component (ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (C-1)) was not added, the polyolefin resin (A) (block polypropylene (PP-1), block polypropylene except that (PP-2)) and styrene / ethylene-butylene copolymer weight ratio of (B-1) is changed as shown in Table 1, in the same manner as in example 1, to obtain a thermoplastic elastomer composition It was.
　The results of evaluating physical properties of Examples 1 and 2 and Comparative Example 1 shown in Table 2.
[0106]
[Table 1]

[0107]
[Table 2]

[0108]
　The present invention, gloss change in (the cover will tear line when the airbag operation) unit tear line that occurs in a portion where there is a thickness difference becomes inconspicuous after molding. In addition to variations in the flow properties of the resin due to the shape change of the molded article by blending the fluidity plurality of types having different resin is relaxed, with the change in morphology of the surface of the molded article, in order to now cause irregular reflection is there.
[0109]
　All publications cited herein shall be incorporated herein patents and patent applications as reference.

The scope of the claims

[Requested item 1]The polyolefin resin (A) 10 ~ 80 parts by weight, a styrene-based thermoplastic elastomer (B) 10 ~ 80 parts by weight, and at least a part of which is crosslinked rubber (C) 1 ~ 20 parts by weight (Components (A), (B ) and (the total amount of C) is a composition comprising 100 parts by weight), the type D hardness conforming to JIS K6253 (instantaneous value) is a thermoplastic elastomer composition is 35 or more and 70 or less.
[Requested item 2]
　Component (A), the total amount per 100 parts by mass of the plasticizer (D) from 0 part by mass or more, the thermoplastic elastomer composition of claim 1 comprising 10 parts by weight or less of (B) and (C).
[Requested item 3]
　The rubber (C) is an ethylene-alpha-olefin copolymer rubber and / or ethylene-alpha-olefin thermoplastic elastomer composition according to claim 1 or 2 including a non-conjugated polyene copolymer rubber.
[Requested item 4]
　Thermoplastic elastomer molded article obtained by molding the thermoplastic elastomer composition according to any one of claims 1 to 3.
[Requested item 5]
　Thermoplastic elastomer molded article obtained by injection molding the thermoplastic elastomer composition according to any one of claims 1 to 3.
[Requested item 6]
　The ratio of the thickest portion (L1) and the thinnest portion of the orientation of the molded body thickness perpendicular to the resin flow direction during molding (L2) (L1 / L2) is 2 or more, according to claim 4 or 5, wherein 50 or less thermoplastic elastomer molded body.
[Requested item 7]
　Automobile parts comprising a thermoplastic elastomer molded article according to any one of claims 4-6.
[Requested item 8]
　Automotive part according to claim 7, wherein the airbag cover.