Classifications

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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
  • C08F297/02—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type
  • C08F297/04—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer using a catalyst of the anionic type polymerising vinyl aromatic monomers and conjugated dienes
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  • C08F8/00—Chemical modification by after-treatment
  • C08F8/04—Reduction, e.g. hydrogenation
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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
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  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/01—Hydrocarbons
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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/14—Peroxides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L53/02—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes
  • C08L53/025—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes modified
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2353/00—Characterised by the use of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
  • C08J2353/02—Characterised by the use of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers of vinyl aromatic monomers and conjugated dienes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2423/04—Homopolymers or copolymers of ethene
  • C08J2423/08—Copolymers of ethene
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  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
  • C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2312/00—Crosslinking

Definitions

• the present invention relates to a thermoplastic elastomer composition and a molded article made from the composition.
• Bioplastics which contain materials obtained from biomass-derived raw materials, are becoming increasingly important due to growing environmental awareness and expected dwindling reserves of fossil sources such as natural gas.
• Thermoplastic elastomers are a group of polymers that have become industrially important among plastic materials and are used in a wide variety of applications, e.g. in the automotive sector, consumer products, packaging, pharmaceuticals and construction, and therefore there is a demand for materials that contain thermoplastic elastomers to have a low environmental impact.
• Patent Document 1 discloses a polymer composition that includes a thermoplastic elastomer, rubber, or bioplastic, and a plasticizer, the plasticizer being a plant-based raw material, or a raw material product based on an industrial plant, or a raw material product based on an animal fat source.
• Thermoplastic elastomer compositions are required to have low viscosity, excellent fluidity, and little hue unevenness depending on their applications, molding methods, etc.
• Patent Document 1 does not clarify what conditions are necessary for the composition to have low viscosity, excellent fluidity, and little hue unevenness. Therefore, an object of the present invention is to provide a thermoplastic elastomer and a molded article that have low viscosity and excellent flowability, can reduce color unevenness, and can further reduce the environmental load when a softener derived from biomass is used.
• thermoplastic elastomer composition that contains a polypropylene resin, an ethylene- ⁇ -olefin copolymer, a hydrogenated block copolymer, and a softener in specific blend ratios, where the softener satisfies specific conditions, and a molded article that contains the thermoplastic elastomer composition, and thus completed the present invention.
• thermoplastic elastomer composition comprising the following components (A) to (D), which is at least partially crosslinked: (A) 100 parts by mass of polypropylene resin; (B) 40 to 80 parts by mass of an ethylene/ ⁇ -olefin copolymer containing ethylene units and ⁇ -olefin units having 3 to 20 carbon atoms; (C) 80 to 200 parts by mass of a hydrogenated block copolymer which is a hydrogenated product of a block copolymer having at least one block (c1) mainly composed of conjugated diene monomer units and at least one block (c2) mainly composed of vinyl aromatic monomer units; (D) 20 to 250 parts by mass of a softener having a paraffinic carbon atom content (% C P ) of 80% or more and 100% or less, as measured in accordance with ASTM D3238-85 or ASTM D2140.
• % C P paraffinic carbon atom content
• thermoplastic elastomer composition according to any one of [1] to [3], wherein the softener (D) has a kinetic viscosity at 40° C. of 40 mm 2 /s or more and 150 mm 2 /s or less.
• thermoplastic elastomer composition according to any one of [1] to [4], wherein the softener (D) has a density of 865 kg/ m3 or less at 15°C.
• thermoplastic elastomer composition according to any one of [1] to [5], wherein the pour point of the softener (D) is -10°C or lower.
• thermoplastic elastomer composition according to any one of [1] to [5], wherein the polypropylene-based resin (A) is at least one selected from the group consisting of propylene homopolymers, random copolymers of propylene and an ⁇ -olefin other than propylene, and block copolymers of propylene and an ⁇ -olefin other than propylene.
• the polypropylene-based resin (A) is at least one selected from the group consisting of propylene homopolymers, random copolymers of propylene and an ⁇ -olefin other than propylene, and block copolymers of propylene and an ⁇ -olefin other than propylene.
• thermoplastic elastomer composition according to any one of [1] to [7], wherein the polypropylene-based resin (A) consists of only propylene homopolymer.
• thermoplastic elastomer composition according to any one of [1] to [8], further comprising a lubricant.
• lubricant contains a polyorganosiloxane.
• thermoplastic elastomer composition according to any one of [1] to [10], further comprising a crosslinking agent.
• thermoplastic elastomer composition according to [11] containing 2 parts by mass or more of the crosslinking agent per 100 parts by mass of the propylene-based resin (A).
• thermoplastic elastomer composition according to any one of [1] to [12].
• An automobile interior material comprising the injection molded article according to [13].
• the present invention can provide a thermoplastic elastomer composition and molded article that have low viscosity, excellent fluidity, and reduced color unevenness, and when a biomass-derived softener is used, can further reduce the environmental impact.
• polymer is used to encompass homopolymers and copolymers, unless otherwise specified.
• a numerical range expressed using “to” means a range that includes the numerical values before and after “to” as the lower and upper limits.
• thermoplastic elastomer composition contains the following components (A) to (D), and is at least partially crosslinked: (A) 100 parts by mass of polypropylene resin; (B) 40 to 80 parts by mass of an ethylene/ ⁇ -olefin copolymer containing ethylene units and ⁇ -olefin units having 3 to 20 carbon atoms; (C) 80 to 200 parts by mass of a hydrogenated block copolymer which is a hydrogenated product of a block copolymer having at least one block (c1) mainly composed of conjugated diene monomer units and at least one block (c2) mainly composed of vinyl aromatic monomer units; (D) 20 to 250 parts by mass of a softener having a paraffinic carbon atom content (% C P ) of 80% or more and 100% or less, as measured in accordance with ASTM D3238-85 or ASTM D2140.
• the thermoplastic elastomer composition according to the present invention will
• the polypropylene-based resin (A) used in the present invention is a propylene homopolymer or a copolymer of propylene and an olefin other than propylene.
• the polypropylene-based resin (A) is preferably at least one selected from the group consisting of a propylene homopolymer, a random copolymer of propylene and an ⁇ -olefin other than propylene, and a block copolymer of propylene and an ⁇ -olefin other than propylene.
• Suitable raw olefins other than propylene for the polypropylene resin (A) include ⁇ -olefins having preferably 2 or 4 to 20 carbon atoms, specifically ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, etc.
• the polypropylene resin (A) is a copolymer of propylene and an olefin other than propylene
• the polymerization mode may be either random or block, so long as a resinous product is obtained.
• These polypropylene resins may be used alone or in combination of two or more.
• the polypropylene resin (A) used in the present invention is preferably a propylene polymer having a propylene content of 40 mol% or more, and more preferably a propylene polymer having a propylene content of 50 mol% or more.
• polypropylene-based resins (A) propylene homopolymers, propylene-ethylene block copolymers, propylene-ethylene random copolymers, propylene-ethylene-butene random copolymers, etc. are even more preferred. Furthermore, from the viewpoint of heat resistance, it is particularly preferred that the polypropylene-based resin (A) consists of only propylene homopolymers.
• the polypropylene resin (A) used in the present invention has a melting point in the range of usually 80 to 170°C, preferably 120 to 170°C.
• the polypropylene resin (A) used in the present invention has an MFR (ASTM D1238-65T, 230° C., 2.16 kg load) in the range of usually 0.01 to 100 g/10 min, preferably 0.05 to 50 g/10 min.
• the polypropylene resin (A) used in the present invention preferably has an isotactic three-dimensional structure, but may also have a syndiotactic structure, a mixture of these structures, or a structure partially containing an atactic structure.
• the polypropylene resin (A) used in the present invention is polymerized by various known polymerization methods.
• the polypropylene-based resin (A) used in the present invention may be a polymer obtained using only fossil fuel-derived olefins such as fossil fuel-derived propylene as a raw material, a polymer obtained using only biomass-derived olefins such as biomass-derived propylene as a raw material, or a polymer obtained using a mixture of fossil fuel-derived olefins and biomass-derived olefins as a raw material, or may be a mixture of two or more of these polymers.
• fossil fuels refer to petroleum, coal, natural gas, shale gas, and other substances that have been fossilized by deposition and pressure over hundreds of millions of years from the remains of animals and plants
• fossil fuel-derived olefins are olefins obtained from these fossil fuels.
• 14C is not detectable in fossil-derived carbon because the time that has passed is sufficiently longer than the half-life of the 14C isotope, which is 5,730 years.
• Biomass refers to any renewable natural raw material and its residue, whether plant- or animal-derived, including fungi, yeast, algae, and bacteria, and biomass-derived olefins refer to olefins obtained from this biomass.
• Biomass-derived carbon contains a certain amount of 14C isotope as carbon (ratio of about 10-12 ).
• the ethylene/ ⁇ -olefin copolymer (B) used in the present invention contains ethylene units and ⁇ -olefin units having 3 to 20 carbon atoms.
• the ethylene/ ⁇ -olefin copolymer (B) can be obtained, for example, by copolymerizing ethylene with an ⁇ -olefin having 3 to 20 carbon atoms.
• ⁇ -olefins 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.
• ⁇ -olefins having 3 to 12 carbon atoms are preferred, and propylene, 1-butene, and 1-octene are more preferred.
• the ethylene- ⁇ -olefin copolymer (B) may further contain a monomer unit having an unsaturated bond, if necessary.
• a monomer unit having an unsaturated bond there are no particular limitations on such monomers, but from the viewpoint of economy, conjugated diolefins such as butadiene and isoprene, non-conjugated diolefins such as 1,4-hexadiene, cyclic diene compounds such as dicyclopentadiene and norbornene derivatives, and acetylenes are preferred, and among these, ethylidenenorbornene (ENB) and dicyclopentadiene (DCP) are more preferred.
• conjugated diolefins such as butadiene and isoprene
• non-conjugated diolefins such as 1,4-hexadiene
• cyclic diene compounds such as dicyclopentadiene and norbornene derivatives
• the Mooney viscosity (ML) of the ethylene/ ⁇ -olefin copolymer (B) measured at 100°C is not particularly limited, but from the viewpoint of dispersibility in the thermoplastic elastomer composition of the present invention, it is preferably 20 to 150, more preferably 50 to 120.
• the Mooney viscosity (ML) of the ethylene/ ⁇ -olefin copolymer (B) is measured according to ASTM D1646.
• the ethylene/ ⁇ -olefin copolymer (B) is preferably produced using a metallocene catalyst.
• the metallocene catalyst is not particularly limited, and examples thereof include those consisting of a cyclopentadienyl derivative of a Group IV metal such as titanium or zirconium and a cocatalyst.
• Metallocene catalysts are not only highly active as polymerization catalysts, but also produce polymers with narrower molecular weight distributions than Ziegler catalysts and the like, and can more uniformly distribute the ⁇ -olefin monomers having 3 to 20 carbon atoms, which are comonomers in the copolymer.
• the ethylene/ ⁇ -olefin copolymer (B) used in the present invention may be a polymer obtained using only fossil fuel-derived ethylene, ⁇ -olefins, and other fossil fuel-derived olefins as a raw material, a polymer obtained using only biomass-derived ethylene, ⁇ -olefins, and other biomass-derived olefins as a raw material, or a polymer obtained using a mixture of fossil fuel-derived olefins and biomass-derived olefins as a raw material, or may be a mixture of two or more of these polymers.
• the copolymerization ratio of the ⁇ -olefin in the ethylene/ ⁇ -olefin copolymer (B) is not particularly limited, but is preferably 1 to 60 mass%, more preferably 10 to 50 mass%, and even more preferably 20 to 45 mass%.
• the density of the ethylene/ ⁇ -olefin copolymer (B) is not particularly limited, but is preferably 0.80 to 0.90 g/cm 3 , and more preferably 0.85 to 0.89 g/cm 3. By setting the density of the ethylene/ ⁇ -olefin copolymer (B) within the above range, the flexibility of the molded article is further improved.
• the ethylene/ ⁇ -olefin copolymer (B) has long chain branches.
• long chain branches refer to branches with 3 or more carbon atoms. By having long chain branches, it is possible to obtain molded products with high strength and low density.
• known copolymers can be used, for example, those described in the specification of U.S. Patent No. 5,278,272 can be used.
• the ethylene/ ⁇ -olefin copolymer (B) preferably has a melting point peak in differential scanning calorimetry (DSC) in a temperature range above room temperature.
• DSC differential scanning calorimetry
• the MFR (190°C, 2.16 kg load; compliant with ASTM D1238) of the ethylene- ⁇ -olefin copolymer (B) is not particularly limited, but is preferably 0.01 to 100 g/10 min, and more preferably 0.2 to 10 g/10 min. By setting the MFR within the above range, a molded product with excellent balance between molding flowability and mechanical strength can be obtained.
• the content of ethylene- ⁇ -olefin copolymer (B) is 40 to 80 parts by mass, preferably 50 to 70 parts by mass, per 100 parts by mass of the polypropylene resin (A) from the viewpoint of the balance of molding flowability, color unevenness, and flexibility.
• the hydrogenated block copolymer (C) used in the present invention is a hydrogenated product of a block copolymer having at least one each of a block (c1) (sometimes referred to as “block (c1)” in this specification) mainly composed of a conjugated diene monomer unit and a block (c2) (sometimes referred to as “block (c2)” in this specification) mainly composed of a vinyl aromatic monomer unit.
• the term "vinyl aromatic monomer unit” refers to a structural unit of a polymer resulting from polymerization of a vinyl aromatic compound monomer, and the structure of the unit is a molecular structure in which two carbon atoms of a substituted ethylene group derived from a substituted vinyl group are the binding sites.
• conjugated diene monomer unit refers to a structural unit of a polymer resulting from polymerization of a conjugated diene monomer, and the structure of the unit is a molecular structure in which two carbon atoms of an olefin derived from a conjugated diene monomer are the binding sites.
• mainly composed means that the copolymer block contains 50% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more of monomer units derived from a conjugated diene monomer (or a vinyl aromatic monomer).
• a block mainly composed of conjugated diene monomer units means that the block contains 50% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more of monomer units derived from a conjugated diene monomer.
• a block mainly composed of vinyl aromatic monomer units means that the block contains 50% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more of monomer units derived from a vinyl aromatic monomer.
• examples of the block (c1) mainly composed of conjugated diene monomer units include a homopolymer block (c10) (sometimes referred to as “polymer block (c10)” in this specification) consisting of only conjugated diene monomer units, and a copolymer block (c11) (sometimes referred to as “copolymer block (c11)” in this specification) that mainly contains conjugated diene monomer units and further contains vinyl aromatic monomer units.
• block (c2) mainly composed of vinyl aromatic monomer units include a homopolymer block (c20) composed only of vinyl aromatic monomer units, and a copolymer block (c21) mainly composed of vinyl aromatic monomer units and further containing conjugated diene monomer units.
• the vinyl aromatic monomer is not particularly limited, and examples thereof include vinyl aromatic compounds such as styrene, ⁇ -methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. These may be used alone or in combination of two or more. Among these, styrene is preferred from the viewpoint of economy.
• the conjugated diene monomer is a diolefin having one pair of conjugated double bonds, such as 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.
• 1,3-butadiene butadiene
• 2-methyl-1,3-butadiene isoprene
• 2,3-dimethyl-1,3-butadiene 1,3-pentadiene
• 2-methyl-1,3-pentadiene 2-methyl-1,3-pentadiene
• 1,3-hexadiene 1,3-hexadiene.
• butadiene and isoprene are preferred from the viewpoint of economic efficiency. These may be used alone or in combination of two or more types.
• the monomers used as raw materials for the hydrogenated block copolymer (C2) may be any of monomers derived from biomass, monomers derived from fossil fuels, or mixtures thereof.
• each block in the hydrogenated block copolymer of the present embodiment is not particularly limited, and any suitable arrangement may be adopted.
• the hydrogenated block copolymer may be a linear block copolymer represented by SB, S(BS) n1 (wherein n1 represents an integer of 1 to 3), S(BSB) n2 (wherein n2 represents an integer of 1 to 2), or a copolymer represented by (SB) n3 X (wherein n3 represents an integer of 3 to 6, and X represents a coupling agent residue such as silicon tetrachloride, tin tetrachloride, or a polyepoxy compound).
• SB linear block copolymers of SB type 2 (diblock), SBS type 3 (triblock), and SBSB type 4 (t
• the content of vinyl aromatic monomer units in the hydrogenated block copolymer (C) is 30-80% by mass, and from the viewpoint of heat resistance and dispersibility, it is preferably 40-80% by mass, and more preferably 50-70% by mass. By making the content of vinyl aromatic monomer units 30% by mass or more, the mechanical properties can be further improved, and by making it 80% by mass or less, the low-temperature properties can be further improved.
• the content of vinyl aromatic monomer units in the hydrogenated block copolymer (C) can be measured by nuclear magnetic resonance spectroscopy (NMR).
• the content of the vinyl aromatic monomer unit block in the hydrogenated block copolymer (C) is preferably 10% by mass or more, more preferably 10 to 40% by mass.
• the content of the vinyl aromatic compound polymer block in the hydrogenated block copolymer (C) is defined by the following formula using the mass of the vinyl aromatic compound polymer block (excluding vinyl aromatic compound polymers having an average degree of polymerization of about 30 or less) obtained by a method of oxidatively decomposing a copolymer before hydrogenation with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in I.M.Kolthoff, et al., J.Polym.Sci.1,429(1946), hereinafter also referred to as "osmium tetroxide decomposition method").
• Content of vinyl aromatic compound polymer block (mass %) (mass of vinyl aromatic compound polymer block in copolymer before hydrogenation/mass of
• the hydrogenated block copolymer (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 distinguished.
• the distribution of the vinyl aromatic monomer units in each polymer block is not particularly limited, and may be uniform, tapered, stepped, convex, or concave.
• a crystalline portion may be present in the polymer block.
• the distribution of vinyl units in the conjugated diene monomer units in each polymer block is not particularly limited, and may be biased, for example.
• Methods for controlling the distribution of vinyl units include adding a vinylizing agent during polymerization and changing the polymerization temperature.
• the distribution of the hydrogenation rate of the conjugated diene monomer units may be biased.
• the distribution of the hydrogenation rate can be controlled by changing the distribution of vinyl units, or by using the difference in the hydrogenation rate between the isoprene unit and the butadiene unit after copolymerization of isoprene and butadiene with a hydrogenation catalyst described later.
• the hydrogenated block copolymer (C) has 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 units before hydrogenation hydrogenated.
• the hydrogenation catalyst used for hydrogenation is not particularly limited, and may be any of the following conventionally known homogeneous hydrogenation catalysts: (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, Ru, etc. are supported on carbon, silica, alumina, diatomaceous earth, etc.; (2) so-called Ziegler-type hydrogenation catalysts that use transition metal salts such as organic acid salts or acetylacetone salts of Ni, Co, Fe, Cr, etc., and reducing agents such as organoaluminum; and (3) so-called organometallic complexes of organometallic compounds such as Ti, Ru, Rh, Zr, etc.
• hydrogenation catalysts that may be used include the hydrogenation catalysts described in JP-B-42-008704, JP-B-43-006636, JP-B-63-004841, JP-B-01-037970, JP-B-01-053851, JP-B-02-009041, etc.
• preferred hydrogenation catalysts include reducing organometallic compounds such as titanocene compounds.
• titanocene compounds for example, compounds described in JP-A-08-109219 can be used. 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.
• reducible organometallic compounds include organoalkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.
• the polymerization method for the hydrogenated block copolymer (C) before hydrogenation is not particularly limited, and known methods can be used.
• known methods can be used.
• the methods described in JP-B-36-019286, JP-B-43-017979, JP-B-46-032415, JP-B-49-036957, JP-B-48-002423, JP-B-48-004106, JP-B-56-028925, JP-A-59-166518, JP-A-60-186577, etc. can be mentioned.
• the hydrogenated block copolymer (C) may have a polar group.
• polar groups include hydroxyl groups, carboxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, acid anhydride groups, thiocarboxylic acid groups, aldehyde groups, thioaldehyde groups, carboxylate groups, amide groups, sulfonic acid groups, sulfonate groups, phosphoric acid groups, phosphate 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, alkoxy silicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronate salt groups, alkoxy tin groups, and phenyl tin groups.
• the vinyl bond content in the conjugated diene monomer units in the pre-hydrogenated copolymer in the hydrogenated block copolymer (C) is preferably 5 mol% or more from the viewpoints of flexibility and scratch resistance, and is preferably 70 mol% or less from the viewpoints 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 even more preferably 10 to 25 mol%.
• the vinyl bond content here means the ratio of 1,2-bonds and 3,4-bonds to the 1,2-bonds, 3,4-bonds and 1,4-bonds incorporated in the conjugated diene before hydrogenation.
• the vinyl bond content can be measured by NMR.
• the weight average molecular weight of the hydrogenated block copolymer (C) before crosslinking is not particularly limited, but is preferably 50,000 or more from the viewpoint of scratch resistance, and is preferably 400,000 or less from the viewpoint of molding flowability, 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 is preferably close to 1 from the viewpoint of scratch resistance.
• the weight average molecular weight and number average molecular weight can be determined by gel permeation chromatography (GPC; Shimadzu Corporation, device name "LC-10") using tetrahydrofuran (1.0 mL/min) as a solvent and an oven temperature of 40°C, using TSKgelGMHXL columns (4.6 mmID x 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 weights.
• the content of hydrogenated block copolymer (C) is 80 to 200 parts by mass relative to 100 parts by mass of the polypropylene resin (A), and from the viewpoint of a balance between scratch resistance and flexibility, it is preferably 90 to 170 parts by mass. If the content of hydrogenated block copolymer (C) is less than 80 parts by mass, flexibility and scratch resistance are insufficient, and if it exceeds 200 parts by mass, mechanical properties may be poor.
• the hydrogenated block copolymer (C) preferably includes a hydrogenated block copolymer (C1) that is a hydrogenated product of a block copolymer having at least one each of a copolymer block (c11) that mainly contains conjugated diene monomer units and further contains vinyl aromatic monomer units, and a block (c2) mainly containing vinyl aromatic monomer units, as the block (c1) mainly containing conjugated diene monomer units.
• the hydrogenated block copolymer (C) may be composed only of the hydrogenated block copolymer (C1), or may further include, in addition to the hydrogenated block copolymer (C1), a hydrogenated block copolymer (C2) that is a hydrogenated product of a block copolymer consisting of one or more polymer blocks (c10) composed of conjugated diene monomer units and one or more blocks (c2) mainly containing vinyl aromatic monomer units.
• the copolymer block (c11) mainly containing conjugated diene monomer units and further containing vinyl aromatic monomer units is not particularly limited, and the above-mentioned conjugated diene monomers and vinyl aromatic monomers can be used. Among them, from the viewpoint of the balance between mechanical strength and impact resistance, preferred combinations include a block containing butadiene units and styrene units, a block containing isoprene units and styrene units, etc.
• the copolymer block (c11) may contain at least conjugated diene monomer units as a main component, and the content of each monomer is not particularly limited.
• the content of vinyl aromatic monomer units in the copolymer block (c11) is preferably 10% by mass or more and less than 50% by mass, and more preferably 20% by mass or more and less than 50% by mass.
• conjugated diene monomers can be used as the conjugated diene monomers constituting the polymer block (c10) consisting of conjugated diene monomer units.
• a polymer block (c10) is typically a homopolymer block consisting only of conjugated diene monomer units, and suitable examples thereof include a homopolymer block consisting only of butadiene units and a homopolymer block consisting only of isoprene units.
• the polymer block (c10) does not necessarily completely exclude the presence of monomer units other than the conjugated diene monomer units, so long as it can exert the same effect as a homopolymer block consisting only of conjugated diene monomer units, and may contain, for example, a small amount of vinyl aromatic monomer units that can be unavoidably mixed in due to the manufacturing process.
• the block (c2) mainly composed of vinyl aromatic monomer units may be, as described above, a homopolymer block (c20) composed only of vinyl aromatic monomer units, or may be a copolymer block (c21) mainly composed of vinyl aromatic monomer units and further containing conjugated diene monomer units, but is preferably a homopolymer block (c20) composed only of vinyl aromatic monomer units.
• the hydrogenated block copolymer (C1) can be obtained from the vinyl aromatic monomer and the conjugated diene monomer by the above-mentioned method.
• (Step A1) forming a block (c2) mainly composed of vinyl aromatic monomer units from a vinyl aromatic monomer;
• (Step A2) A block copolymer is obtained by a step including a step of copolymerizing the block (c2) obtained in the step A1 with a conjugated diene monomer and a vinyl aromatic monomer, and then (Step A3)
• the block copolymer can be obtained by carrying out a step of reacting the block copolymer with hydrogen in the presence of the hydrogenation catalyst.
• the hydrogenated block copolymer (C2) can also be obtained from the vinyl aromatic monomer and the conjugated diene monomer by the above-mentioned method.
• Step B1 forming a block (c2) mainly composed of vinyl aromatic monomer units from a vinyl aromatic monomer;
• Step B2 polymerizing the block (c2) obtained in the step A1 with a conjugated diene monomer to obtain a block copolymer, and then
• the block copolymer can be obtained by carrying out a step of reacting the block copolymer with hydrogen in the presence of the hydrogenation catalyst.
• the hydrogenated block copolymer (C) it is preferable to use in combination at least two or more hydrogenated block copolymers, namely (C-1) a hydrogenated block copolymer having a vinyl aromatic monomer unit block content of 20% by mass or more and less than 50% by mass, and (C-2) a hydrogenated block copolymer having a vinyl aromatic monomer unit block content of 50% by mass or more and 80% by mass or less.
• the (C-1) component having a low content of vinyl aromatic monomer units contributes to the low-temperature properties of the thermoplastic elastomer composition, while the (C-2) component having a high content of vinyl aromatic monomer units contributes to stabilization of the morphology of the matrix and domains of the thermoplastic elastomer composition.
• the mass ratio (C-1/C-2) of the (C-1) component to the (C-2) component is preferably 90/10 to 60/40 from the viewpoints of low-temperature properties and mechanical properties.
• the hydrogenated block copolymer (C) contains two or more of the hydrogenated block copolymers (C2)
• the hydrogenated block copolymer (C) contains the hydrogenated block copolymer (C1) and two or more of the hydrogenated block copolymers (C2)
• the hydrogenated block copolymer (C1) and one or more of the hydrogenated block copolymers (C2) may constitute the component (C-1), and one or more of the hydrogenated block copolymers (C2) may constitute the component (C-2).
• the softener (D) used in the present invention has a paraffinic carbon atom content (% C P ) of 80% or more and 100% or less, as determined in accordance with ASTM D3238-85 or ASTM D2140.
• % C P paraffinic carbon atom content
• the obtained thermoplastic elastomer composition has excellent flowability, little color unevenness, and excellent molded appearance.
• the content of paraffinic carbon atoms (% C P ) is preferably 85% or more and 100% or less, more preferably 90% or more and 100% or less.
• the naphthenic carbon atom content (% C N ) is preferably 0% or more and 20% or less, more preferably 0% or more and 10% or less, and even more preferably 0% or more and 5% or less.
• the content of aromatic carbon atoms (% C NA ) is preferably 0% or more and 10% or less, more preferably 0% or more and 5% or less, and further preferably 0% or more and 1% or less.
• the %C P , %C N and %C A are determined by a measurement method in accordance with ASTM D 3238-85 or ASTM D 2140.
• %C P , %C N and %C A respectively mean the percentage of the paraffin carbon number to the total carbon number, the percentage of the naphthene carbon number to the total carbon number, and the percentage of the aromatic carbon number to the total carbon number, all determined by the above measurement methods.
• ASTM D 3238-85 is related to the Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the ndM Method, and specifies ring analysis by the ndM method.
• This ring analysis by the ndM method is a type of structural group analysis used in the composition analysis of high boiling point petroleum fractions, and is a method of calculating the following carbon distribution and ring content from a formula or chart based on the measured values of the refractive index n, density d, and average molecular weight M of a sample at 20°C or 70°C.
• ASTM D2140 is related to the Standard Practice for Calculating Carbon-Type Composition of Insulating Oils of Petroleum Origin.
• the carbon-type composition of the softener (D) can be calculated using viscosity, density, and refractive index, and aromatic carbon % (% C A ), naphthene carbon % (% C N ), and paraffin carbon % (% C P ) can be obtained through ring analysis.
• the density of the softener (D) at 15°C is preferably 890 kg/ m3 or less, more preferably 865 kg/ m3 or less, and even more preferably 850 kg/ m3 or less.
• the density of the softener (D) at 15°C is preferably 800 kg/ m3 or more, more preferably 820 kg/ m3 or more.
• the density of the softener (D) is specifically a value measured at a predetermined measurement temperature (for example, 15° C.) in accordance with the measurement method of ASTM D 4052.
• the kinetic viscosity of the softener (D) at 40° C. is preferably 40 mm 2 /s or more and 300 mm 2 /s or less, more preferably 40 mm 2 /s or more and 200 mm 2 /s or less, and even more preferably 40 mm 2 /s or more and 150 mm 2 /s or less, from the viewpoint of fluidity.
• the kinetic viscosity of the softener (D) is a value measured at the measurement temperature (e.g., 40° C.) in accordance with the measurement method of ISO 3104.
• the pour point of the softener (D) is preferably -10°C or lower, more preferably -15°C or lower, and even more preferably -20°C or lower, in terms of flexibility under low temperature conditions.
• the pour point of the softener (D) is usually -50°C or higher, preferably -40°C or higher, and more preferably -30°C or higher.
• the pour point of the softener (D) is a value measured in accordance with ASTM D-6749.
• the softener (D) has an evaporation loss of 0.2 mass% or less at 200°C and normal pressure for 1 hour, preferably 0.15 mass% or less, more preferably 0.13 mass% or less, from the viewpoint of reducing the amount of volatile components (e.g., improving fogging properties).
• the evaporation loss of 1.2 mass% or less at 200°C and normal pressure for 3 hours is preferably 1.2 mass% or less, more preferably 1.0 mass% or less, and more preferably 0.8 mass% or less.
• the evaporation loss of 2.5 mass% or less at 200°C and normal pressure for 5 hours is preferably 2.0 mass% or less, more preferably 1.5 mass% or less.
• the thermoplastic elastomer composition of the present invention has a low content of volatile components, which is desirable, and for example, has good fogging properties.
• the evaporation loss of the softener (D) is specifically a value measured by the method described in "(5-2) Loss on evaporation upon heating" in the following examples.
• the softener (D) may be any softener as long as it satisfies the above-mentioned properties.
• it may be a refined mineral oil, a synthetic oil obtained by polymerizing an olefin monomer, a biomass-derived softener described below, or a mixture of two or more of these.
• the softener (D) preferably contains a biomass-derived softener, and more preferably contains only a biomass-derived softener.
• the obtained thermoplastic elastomer composition not only has excellent flowability, less color unevenness, and excellent molded appearance, but also reliably reduces the environmental load.
• biomass-derived softeners tend to have a lower density at 15°C than refined mineral oils and synthetic oils (for example, the density of the softener (D) is 865 kg/ m3 or less), which is advantageous from the viewpoint of reducing the weight of molded articles.
• the biomass-derived softener is a softener obtained from plants such as cultivated plants and natural plants, and animal fat sources as raw materials.
• the softener (D) may contain not only a biomass-derived softener but also a fossil fuel-derived softener, but from the viewpoint of more excellent reduction in environmental load, it is preferable that the softener (D) contains a biomass-derived softener and does not contain a fossil fuel-derived softener.
• the fossil fuel-derived softener means a softener obtained through a manufacturing process including a process such as processing from a fossil fuel such as natural gas.
• Biomass-derived softeners derived from plant or animal fat sources are organic compounds or mixtures of organic compounds obtained from the feedstock through a manufacturing process that may include, for example, extraction or processing steps.
• Biomass-derived softeners often contain multiple specific organic compounds derived from multiple organic compounds contained in raw materials such as plants (e.g., sugar cane, rapeseed), animal fat sources (e.g., butter), etc., and further contain these organic compounds in a specific compositional distribution. Therefore, it is generally difficult for a biomass-derived softener and a fossil fuel-derived softener to have the same chemical composition.
• Suitable plants from which the biomass-derived softener can be produced include, for example, trees, sunflowers, rapeseed, oilseed, corn, linseed, jojoba, peanuts, coconuts, thistles, castor beans, soybeans, palms, hemp, poppies, olives, sugar cane, sugar beets, and other grains.
• Suitable animal fat sources from which to make the biomass-derived tenderizer include, for example, butter, lard, tallow, hemp, herring, sardines, and other animal fats.
• the raw material for the biomass-derived softener is preferably a plant, more preferably a cultivated plant.
• a preferred embodiment is vegetable oil obtained from a plant such as the above-mentioned cultivated plant.
• suitable vegetable oils include, for example, lignin oil, sunflower oil, rapeseed oil, rapeseed oil, corn oil, hemp seed oil, olive oil, linseed oil, soybean oil, palm oil, poppy seed oil, and jojoba oil.
• Another preferred embodiment of the raw material for the biomass-derived softener is a raw material that may contain starch, cellulose, or lignin and is obtained from plants such as the above-mentioned cultivated plants.
• these raw materials there are raw materials obtained from sugar cane or sugar beet, raw materials obtained from palm oil, raw materials obtained from sunflowers, raw materials obtained from rapeseed, etc.
• a plant-derived softener classified into the following ( ⁇ ) to ( ⁇ ) is preferable.
• the biomass-derived softener ( ⁇ ) in the above category ( ⁇ ) is a softener containing a fatty acid ester represented by the following formula ( ⁇ ):
• R 1 is a substituted or unsubstituted aryl group having 1 to 22 carbon atoms, preferably 1 to 10 carbon atoms, more preferably a substituted or unsubstituted phenyl group; a substituted or unsubstituted, linear or branched alkyl group having 1 to 22 carbon atoms; or a substituted or unsubstituted, linear or branched alkylene group having 1 to 22 carbon atoms and having 1 to 3 double bonds, preferably 1 double bond;
• R2 is a substituted or unsubstituted, linear or branched, saturated or unsaturated aliphatic hydrocarbon group having 1 to 21 carbon atoms, preferably a linear, saturated or unsaturated aliphatic hydrocarbon group having 1 to 21 carbon atoms, more preferably a linear unsaturated aliphatic hydrocarbon group having 1 to 3 double bonds and having 1 to 21 carbon atoms, and even more preferably a linear unsaturated aliphatic hydrocarbon group having 1
• R 1 is an alkyl group, it is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethyl-hexyl, nonyl, decyl, stearyl, or oleyl, and more preferably 2-ethyl-hexyl, decyl, or oleyl.
• R 1 is an alkylene group having one double bond, the double bond is desirably located at the 9-position of the alkylene group.
• the number of carbon atoms in the groups R1 and R2 is the total number of carbon atoms including the number of carbon atoms in the substituents and side chains, unless otherwise specified.
• R 1 in the fatty acid ester represented by the above formula ( ⁇ ) is preferably a substituted or unsubstituted, linear or branched alkyl group having 1 to 22 carbon atoms, more preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethyl-hexyl, nonyl, decyl, stearyl, or oleyl, and even more preferably 2-ethyl-hexyl, oleyl, or decyl.
• R 2 in the fatty acid ester represented by the above formula ( ⁇ ) is preferably a substituted or unsubstituted, linear or branched, saturated or unsaturated aliphatic hydrocarbon group having 1 to 21 carbon atoms, more preferably a linear, saturated or unsaturated aliphatic hydrocarbon group having 1 to 21 carbon atoms, even more preferably a linear unsaturated aliphatic hydrocarbon group having 1 to 21 carbon atoms and 1 to 3 double bonds, and even more preferably a linear unsaturated aliphatic hydrocarbon group having 1 to 17 carbon atoms and 1 double bond.
• Preferred examples of the fatty acid ester represented by the above formula ( ⁇ ) include alkyl arachidonates, alkyl linoleates, alkyl linolenates, alkyl laurates, alkyl myristates, alkyl oleates, alkyl caprates, alkyl stearates, alkyl palmitates, alkyl caprylates, alkyl caproates, alkyl butanoates, and alkyl behenates.
• fatty acid esters 2-ethylhexyl oleate, 2-ethylhexyl stearate, decyl oleate, decyl stearate, oleyl oleate, and oleyl stearate are preferred.
• the fatty acid esters may be used alone or in combination of two or more.
• the biomass-derived softener ( ⁇ ) in the above category ( ⁇ ) is a softener containing a triglyceride represented by the following formula ( ⁇ ).
• a triglyceride is an ester of glycerin in which all hydroxyl groups of a fatty acid having three hydroxyl groups are esterified.
• R 3 , R 4 and R 5 are each independently a substituted or unsubstituted, linear or branched alkyl group having 1 to 22 carbon atoms; or a substituted or unsubstituted, linear or branched alkylene group having 1 to 22 carbon atoms and having 1 to 3 double bonds, preferably 1 double bond.
• R 3 , R 4 and R 5 in the triglyceride represented by the above formula ( ⁇ ) are all the same.
• a preferred embodiment of R 3 , R 4 and R 5 in the triglyceride represented by the above formula ( ⁇ ) is oleyl, and another preferred embodiment is an organic group having 17 carbon atoms represented by the following formula ( ⁇ 1).
• the biomass-derived softener ( ⁇ ) of the above class ( ⁇ ) is a softener containing a dimer acid ester, which is a dimer acid compound represented by the following formula ( ⁇ ).
• a dimer acid ester is usually a reaction product between a dimer acid and a linear or branched, saturated or unsaturated alcohol having 1 to 22 carbon atoms and 1 to 3 carbon-carbon double bonds.
• n is an integer of 1 or more, preferably an integer of 1 to 40, and more preferably an integer of 1 to 30.
• R 6 and R 7 are each independently a substituted or unsubstituted, linear or branched alkyl group having 1 to 22 carbon atoms, and are preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethyl-hexyl, nonyl, decyl, stearyl, or oleyl.
• Dimer acid esters are esters of unsaturated fatty acid dimers. Dimer fatty acids are obtained by dimerization of each fatty acid. The esters are obtained by reacting the above dimer acids with alcohols. As the alcohols that are the raw materials for dimer acid esters, methanol, 2-ethylhexyl alcohol, tridecyl alcohol, and oleyl alcohol are preferred.
• biomass-derived softeners ( ⁇ ) to ( ⁇ ) are used as the biomass-derived softener, only one type may be used as the softener, or a mixture of two or more types may be used as the softener.
• the content of the softener (D) is 20 to 250 parts by mass, preferably 50 to 200 parts by mass, per 100 parts by mass of the polypropylene resin (A) in order to achieve good fluidity and reduced color unevenness while suppressing bleeding of the softener.
• thermoplastic elastomer composition of the present invention contains the polypropylene resin (A), the ethylene- ⁇ -olefin copolymer (B), the hydrogenated block copolymer (C), and the softener (D), and is at least partially crosslinked.
• thermoplastic elastomer composition of the present invention preferably satisfies the following requirements (1) to (3): Requirement (1):
• the thermoplastic elastomer composition of the present invention preferably has a melt flow rate (MFR, 230°C, 1.2 kg load) measured in accordance with ASTM D1238 of 20 to 100 g/10 min, more preferably 50 to 90 g/10 min.
• thermoplastic elastomer composition of the present invention preferably has a surface hardness (Shore-A hardness, instantaneous value) measured in accordance with JIS K7215 of 60 to 100, more preferably 60 to 80.
• the surface hardness can be measured by the method described in the examples below.
• the thermoplastic elastomer composition of the present invention preferably has a tensile elongation of 100% or more, more preferably 200% or more, measured in accordance with JIS K 6251.
• the upper limit of the tensile elongation is not particularly limited as long as it does not impair the effects of the present invention, but is, for example, 600%.
• thermoplastic elastomer composition satisfying the above requirements (1) to (3) has properties that make it easy to process by injection molding and the like, have a good feel to the touch, and are highly durable.
• thermoplastic elastomer composition of the present invention preferably satisfies the following requirement (4):
• thermoplastic elastomer composition satisfying the above requirements (1) to (3), desirably satisfying the above requirements (1) to (4) can be produced as follows.
• the MFR and viscosity of the thermoplastic elastomer composition can be adjusted, for example, by changing the amount of organic peroxide added as a crosslinking agent when mixing the raw materials, the thermoplastic elastomer and the polypropylene resin, in an extruder. For example, the more the amount of organic peroxide added, the higher the MFR of the resulting thermoplastic elastomer composition tends to be.
• the surface hardness of the thermoplastic elastomer composition can be adjusted by changing the composition of the thermoplastic elastomer composition. For example, the smaller the amount of softener (D) added, the greater the surface hardness of the resulting thermoplastic elastomer composition tends to be.
• the tensile elongation of the thermoplastic elastomer composition can be adjusted by changing the composition of the thermoplastic elastomer composition.
• the tensile elongation of the resulting thermoplastic elastomer composition tends to increase as the ratio of the hydrogenated block copolymer (C) to the polypropylene resin (A) increases.
• thermoplastic elastomer composition that satisfies the above (1) to (4).
• the thermoplastic elastomer composition of the present invention may consist of only the polypropylene resin (A), the ethylene- ⁇ -olefin copolymer (B), the hydrogenated block copolymer (C), and the softener (D), so long as at least a portion of the composition is crosslinked.
• the thermoplastic elastomer composition of the present invention may contain, in addition to the polypropylene resin (A), the ethylene- ⁇ -olefin copolymer (B), the hydrogenated block copolymer (C), and the softener (D), other components not included in the components (A) to (D) (hereinafter, "other components").
• thermoplastic elastomer composition of the present invention is usually carried out in the presence of a crosslinking agent. Therefore, in a preferred embodiment of the thermoplastic elastomer composition of the present invention, the thermoplastic elastomer composition further contains a crosslinking agent described below. In this case, the thermoplastic elastomer composition may further contain a crosslinking aid described below.
• the thermoplastic elastomer composition of the present invention may further contain a crosslinking agent.
• the crosslinking agent include commonly used crosslinking agents such as organic peroxides, phenolic resins, sulfur, hydrosilicone compounds, amino resins, quinones or derivatives thereof, amine compounds, azo compounds, epoxy compounds, isocyanates, and thermosetting elastomers.
• the crosslinking agent is an organic peroxide. This organic peroxide can promote the decomposition reaction of the polypropylene resin (A) during crosslinking.
• thermoplastic elastomer composition can be further improved, and even when manufacturing a part with a large surface area and a complex shape, the composition has good conformability to a mold and can be filled into the mold more completely without gaps.
• organic peroxides 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-4,4-bis(t-butylperoxy)butane.
• peroxyketals such as bis(t-butylperoxy)valerate; di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, ⁇ , ⁇ '-bis(t-butylperoxy-m-isopropyl)benzene, ⁇ , ⁇ '-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and other dialkyl peroxides; acetyl peroxide, isobutyryl peroxide, diacyl peroxides such as butyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxid
• 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, di-t-butylperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 are preferred from the standpoint of thermal decomposition temperature and crosslinking performance.
• the crosslinking agent is 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane.
• the crosslinking agent is contained in an amount of preferably 2 parts by mass or more and preferably 6 parts by mass or less, and more preferably 4 parts by mass or less, per 100 parts by mass of the propylene-based resin (A), from the viewpoint of molding flowability.
• the thermoplastic elastomer composition of the present invention contains an organic peroxide as a crosslinking agent, the amount of the organic peroxide is preferably 2 to 6 parts by mass, more preferably 2 to 4 parts by mass, per 100 parts by mass of the polypropylene resin (A), from the viewpoint of molding flowability.
• a crosslinking aid can be blended in the crosslinking treatment with the organic peroxide. That is, when the thermoplastic elastomer composition of the present invention contains the organic peroxide as the crosslinking agent, the thermoplastic elastomer composition may further contain a crosslinking aid.
• the crosslinking aid that can be used in the present invention is preferably a monofunctional monomer or a polyfunctional monomer, since it can control the crosslinking reaction rate.
• a radically polymerizable vinyl monomer is preferable, and examples thereof 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.
• monofunctional monomers include 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, methylmaleic anhydride, 1,2-dimethylmaleic anhydride, ethylmaleic anhydride, phenylmaleic anhydride, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, and N-cet
• styrene, acrylonitrile, methacrylonitrile, methyl acrylate, maleic anhydride, and N-methylmaleimide are preferred from the viewpoints of ease of reaction and versatility.
• monofunctional monomers may be used alone or in combination of two or more.
• the polyfunctional monomer is a monomer having multiple radically polymerizable functional groups as functional groups, and a monomer having a vinyl group is preferable.
• the number of functional groups in the polyfunctional monomer is preferably two or three.
• 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-phenylene bismaleimide, diallyl phthalate, tetraallyloxyethane, 1,2-polybutadiene, etc., and divinylbenzene and triallyl isocyanurate are more preferred. These polyfunctional monomers may be used alone or in combination of two or more.
• the crosslinking aid as described above is preferably used in an amount of 0.5 to 5 parts by mass, and more preferably 1 to 3 parts by mass, per 100 parts by mass of the polypropylene resin (A) from the viewpoint of molding flowability.
• thermoplastic elastomer composition of the present invention may contain, as other components, other than the crosslinking agent and crosslinking aid, for example, lubricants (polyorganosiloxane, etc.), inorganic fillers, plasticizers, and other additives, as long as the purpose of the present invention is not impaired.
• lubricants polyorganosiloxane, etc.
• inorganic fillers plasticizers, and other additives
• the thermoplastic elastomer composition of the present invention may contain a lubricant.
• the lubricant include polyorganosiloxane, fluorine-based resin, fatty acid metal salt, aliphatic amide, etc.
• polyorganosiloxane is preferred from the viewpoint of wear resistance.
• the thermoplastic elastomer composition of the present invention contains polyorganosiloxane as a lubricant.
• the structure of the polyorganosiloxane is not particularly limited, but from the viewpoints of abrasion resistance and touch, it is preferred that the polyorganosiloxane has a straight-chain, branched, or crosslinked polymer structure.
• the polyorganosiloxane is not particularly limited, and known polyorganosiloxanes can be used.
• Preferred polyorganosiloxanes are polymers containing siloxane units having a substituent such as an alkyl group, a vinyl group, or an aryl group. Among these, polyorganosiloxanes having an alkyl group are particularly preferred, and polyorganosiloxanes having a methyl group are even more preferred.
• polyorganosiloxanes having methyl groups include polydimethylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, etc. Among these, polydimethylsiloxane is preferred.
• the kinematic viscosity of the polyorganosiloxane is not particularly limited, but from the viewpoint of abrasion resistance, the kinematic viscosity (25 ° C.) specified in JIS Z8803 is preferably 5000 centistokes (cSt) or more.
• the dispersibility of the polyorganosiloxane in the thermoplastic elastomer composition of the present invention tends to be improved, and the appearance is excellent, and the quality stability during melt extrusion also tends to be further improved, so the kinematic viscosity of the polyorganosiloxane is preferably less than 2 million cSt.
• the kinematic viscosity of the polyorganosiloxane is more preferably 10,000 cSt or more and less than 2 million cSt, and even more preferably 50,000 cSt or more and less than 2 million cSt.
• the polyorganosiloxane may be added to the thermoplastic elastomer composition in the form of a masterbatch in which the polyorganosiloxane is mixed with a thermoplastic resin.
• the amount of polyorganosiloxane added is usually 5 to 20 parts by mass, preferably 8 to 15 parts by mass, per 100 parts by mass of the polypropylene resin (A) in order to suppress bleeding during molding while ensuring good abrasion resistance.
• inorganic fillers examples include calcium carbonate, magnesium carbonate, silica, carbon black, glass fiber, titanium oxide, clay, mica, talc, magnesium hydroxide, and aluminum hydroxide.
• plasticizer examples include polyethylene glycol, phthalate esters such as dioctyl phthalate (DOP), and the like.
• additives include, for example, organic and inorganic pigments such as carbon black, titanium oxide, and 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 trisnonylphenylphosphite and distearyl pentaerythritol diphosphite; ultraviolet absorbers such as 2-(2'-hydroxy-5'methylphenyl)benzotriazole and 2,4-dihydroxybenzophenone; bis-[2,2,6,6-tetramethyl-4-piperidinyl]sebacate, tetrakis
• suitable additives include light stabilizers such as (2,2,6,6-tetramethyl-4-piperid
• thermoplastic elastomer composition of the present invention can be obtained by crosslinking a mixture containing the polypropylene resin (A), the ethylene- ⁇ -olefin copolymer (B), the hydrogenated block copolymer (C), and the softener (D).
• the method for performing the crosslinking is not particularly limited and may be a known method.
• the crosslinking is preferably performed in the presence of the crosslinking agent.
• the conditions for the crosslinking reaction are not particularly limited, and suitable conditions can be appropriately adopted depending on the desired physical properties of the thermoplastic elastomer composition of the present invention.
• thermoplastic elastomer composition of the present invention can be produced by a general method using a Banbury mixer, kneader, single screw extruder, twin screw extruder, etc., which are used in the production of ordinary elastomer compositions.
• a production method using a twin screw extruder is preferred from the viewpoint of efficiently achieving dynamic crosslinking of the thermoplastic elastomer.
• a twin screw extruder for example, the polypropylene resin (A) and the crosslinking agent, etc. are added and uniformly and finely dispersed, and other components are further added, thereby causing a crosslinking reaction of the composition and enabling continuous production of the thermoplastic elastomer composition.
• thermoplastic elastomer composition described above through the following processing steps. That is, the polypropylene resin (A), the ethylene- ⁇ -olefin copolymer (B), and the polyorganosiloxane added as necessary are thoroughly mixed and charged into the hopper of the extruder.
• the crosslinking agent may be added to the extruder from the beginning together with the polypropylene resin (A) and the ethylene- ⁇ -olefin copolymer (B), or a part of the crosslinking agent may be added midway through the extruder. Furthermore, a part of the polypropylene resin (A) and the ethylene- ⁇ -olefin copolymer (B), etc.
• the hydrogenated block copolymer (C) may be added midway through the extruder.
• the hydrogenated block copolymer (C) may be added midway through the extruder, or may be added separately at the beginning and midway. In this case, the crosslinking agent and the hydrogenated block copolymer (C) may be mixed in advance and added.
• the softener (D) may also be added from the beginning, added in parts at the beginning and midway, or added only midway.
• the method of adding the softener (D) may be a method of adding a master batch that contains a high concentration of the softener (D) in advance using any thermoplastic resin or elastomer.
• the crosslinking agent accelerates the decomposition reaction, improving molding fluidity. Furthermore, the hydrogenated block copolymer (C) and other components are added, melted and kneaded, and the crosslinking reaction and kneading and dispersion are sufficiently carried out. After that, pellets of the thermoplastic elastomer composition can be obtained by removing the mixture from the extruder.
• the molded article obtained by the present invention contains the thermoplastic elastomer composition of the present invention.
• the molded article can be a film or a sheet.
• the application of the molded article can be an interior material for automobiles.
• Such molded articles can be obtained by molding the thermoplastic elastomer composition using various molding methods.
• the molding methods include injection molding, extrusion molding, vacuum molding, pressure molding, blow molding, calendar molding, and foam molding.
• a molded article (molded product) such as a skin material can be obtained by filling a mold for molding with the above-mentioned thermoplastic elastomer composition that has been heated and melted, cooling and solidifying it, and then demolding it.
• the thermoplastic elastomer composition of the present invention is preferably made into an injection molded body (injection molded product). When made into an injection molded body, it has excellent productivity.
• the shape of the injection molded body is not particularly limited, but from the viewpoint of use as a skin material, it is preferably a film or sheet.
• the injection molded body can be used for various components, but is particularly preferred for use as instrument panels and other automotive interior materials, from the viewpoint that it is possible to injection mold thin-walled molded bodies (thin-walled molded products) with complex shapes with good reproducibility.
• instrument panels are not only thin and have a large surface area, but also typically have complex shapes with grain patterns on the surface, partial openings, curved surfaces as well as flat surfaces, three-dimensional structures, and thick surfaces as well as thin sections.
• an injection molded body with a thin wall and a large surface area can be obtained, making it suitable for instrument panels or components thereof.
• the shape and configuration of the automotive interior material are not particularly limited, and can be appropriately selected according to the application.
• One preferred example is a laminate comprising a layer containing the automotive interior material of this embodiment (hereinafter sometimes referred to as the "skin material layer”) and a layer containing a core material (hereinafter sometimes referred to as the "core material layer”) laminated on the layer containing the automotive interior material.
• the skin material layer a layer containing the automotive interior material of this embodiment
• core material layer a layer containing a core material laminated on the layer containing the automotive interior material.
• the material of the core is not particularly limited, and known materials can be used, such as polypropylene, acrylonitrile butadiene styrene (ABS) resin, polycarbonate/acrylonitrile butadiene styrene alloy (PC/ABS alloy), acrylonitrile styrene copolymer, modified polyphenylene oxide, and resins in which fillers such as talc and glass fiber are mixed as necessary to improve strength.
• ABS acrylonitrile butadiene styrene
• PC/ABS alloy polycarbonate/acrylonitrile butadiene styrene alloy
• acrylonitrile styrene copolymer such as polyphenylene oxide
• modified polyphenylene oxide such as talc and glass fiber are mixed as necessary to improve strength.
• those containing at least one selected from the group consisting of polypropylene, acrylonitrile butadiene styrene (ABS) resin, polycarbonate/acrylonitrile butadiene styrene alloy (PC/ABS alloy), and polyphenylene ether are preferred.
• polypropylene is more preferred from the viewpoint of light weight.
• the layer structure of the laminate of this embodiment is not particularly limited, and may be a two or more layer structure having at least a skin layer and a core layer.
• the skin layer and the core layer do not necessarily need to be in contact with each other, and other layers may be present between the skin layer and the core layer.
• the thickness of the skin layer is not particularly limited, but is preferably 0.5 to 2.0 mm, and more preferably 0.8 to 1.5 mm.
• the thickness of the skin layer is not particularly limited, but is preferably 0.5 to 2.0 mm, and more preferably 0.8 to 1.5 mm.
• the thickness of the core layer is not particularly limited, but is preferably 2.0 to 4.5 mm, and more preferably 2.5 to 3.5 mm.
• the core layer 2.0 mm or more thick the rigidity, heat resistance, and moldability can be improved, and by making it 4.5 mm or less, the cost efficiency and light weight can be improved.
• the laminate of this embodiment preferably further comprises a layer containing a foam material between the skin layer and the core layer, and the foam material more preferably contains a thermosetting urethane foam having a density of 100 to 250 kg/m 3.
• the density of the foam material 100 kg/m 3 or more, it becomes difficult for indentations to be made during handling during production or removal, and handling properties can be further improved.
• the density of the foam material 250 kg/m 3 or less it is possible to impart appropriate flexibility to the laminate. From this viewpoint, it is more preferable that the density of the foam material is 120 to 180 kg/m 3 .
• thermosetting urethane foam is not particularly limited, but semi-rigid thermosetting urethane foam is preferable.
• Semi-rigid thermosetting urethane foam refers to urethane foam with an open cell structure of 90% or more.
• the method for manufacturing the laminate is not particularly limited, and known methods can be used. For example, there is a method in which the skin material, core material, and foam material are molded separately, and then the above members are laminated using a chloroprene-based adhesive or similar to form a layered structure, or a method in which the core material is molded in advance, and then the core material is placed in a mold and molded integrally with the molding of the skin material (integral molding), and the core material and the two members are laminated to form a layered structure.
• the above layer structure it is possible to obtain a laminate that has a uniform thickness, good grain reproducibility, and a skin material with a good feel and appearance, and that can be mass-produced stably even in complex three-dimensional shapes. Furthermore, by using a layer structure of three or more layers that includes the above-mentioned foam material, it is possible to obtain a laminate that makes the most of the soft feel of the skin material.
• the laminate is suitable for use as automotive interior components, including thin-walled, large-surface-area instrument panels, door panels, glove box lids, and the like, which have traditionally been difficult to manufacture by injection molding, and is particularly suitable for instrument panels.
• the instrument panel of this embodiment provides the effects described in the embodiments of the automotive skin material and laminate. Furthermore, because the skin material has good elongation characteristics at low temperatures, it becomes easier to ensure the deployment performance of the passenger airbag at low temperatures, and it is also possible to maintain and improve design freedom, for example by making the skin material in the airbag installation area seamless.
• Shore-A hardness (also called “JIS-A hardness”) was measured as the surface hardness.
• Shore-A hardness was measured by stacking four 2 mm thick sheets as samples and evaluating them in an A type atmosphere at 23°C in accordance with JIS K7215. The hardness at the moment when the probe of the hardness tester was lowered on the sample was measured as the surface hardness (instantaneous value), and the hardness 10 seconds after the probe was lowered was measured as the surface hardness (after 10 s).
• Styrene polymer block content (Os value)
• the styrene polymer block content was measured by the method (osmium tetroxide decomposition method) described in I. M. Kolthoff, et al., J. Polym. Sci. 1, 429 (1946) using the corresponding pre-hydrogenated copolymer. A 0.1 g/125 mL tertiary butanol solution of osmic acid was used for decomposition of the pre-hydrogenated copolymer.
• the styrene polymer block content was calculated by the following formula.
• the styrene polymer block content obtained here is referred to as the "Os value”.
• Styrene polymer block content (Os value; mass%) [(mass of styrene polymer block in copolymer before hydrogenation)/(mass of copolymer before hydrogenation)] ⁇ 100
• the naphthenic carbon atom content (% C N ) proportion of naphthenic carbon atoms
• the paraffinic carbon atom content (% C P ) content of paraffinic carbon atoms
• the aromatic carbon atom content (% C A ) proportion of aromatic carbon atoms
• Measurement equipment Tosoh Corporation (gel permeation chromatograph HLC-8321 GPC) Column: (2x TSKgel GMH6-HT + 2x TSKgel GMH6-HTL (both 7.5 mm ID x 30 cm, Tosoh Corporation) Solvent: o-dichlorobenzene; ODCB (containing 0.025% BHT) Column temperature: 140 ° C. Concentration: 0.1% Flow rate: 1.0 mL/min Detector: differential refractometer (RI) Column calibration: Monodisperse polystyrene (Tosoh Corporation); #3 standard set Molecular weight conversion: Polystyrene conversion / Standard conversion method
• component (A) a homopolymer type polypropylene manufactured by SunAllomer Corporation (melt flow rate (MFR) at 230° C. and a load of 2.16 kg: 0.5 g/10 min; weight average molecular weight: 6.6 ⁇ 10 5 ) (hereinafter referred to as “A-1”) was used.
• component (B) a copolymer of ethylene and 1-octene (manufactured by Dow Chemical Company, product name "Engage 8842”) was used.
• the ethylene content of this copolymer was 55% by mass, and the 1-octene content was 45% by mass (hereinafter referred to as "B-1").
• component (C) As the hydrogenated block copolymer (C) (hereinafter referred to as component (C)), the following hydrogenated products (C1) and (C2) were used.
• (C1) A hydrogenated copolymer having a copolymer block mainly containing conjugated diene monomer units and further containing vinyl aromatic monomer units, and a vinyl aromatic monomer unit block.
• Hydrogenated product (C1-1) As the hydrogenated product (C1) of a copolymer having a copolymer block mainly containing conjugated diene monomer units and further containing vinyl aromatic monomer units, and a vinyl aromatic monomer unit block, a hydrogenated product (C1-1) of a copolymer having a copolymer block mainly containing conjugated diene monomer units and further containing vinyl aromatic monomer units, and a vinyl aromatic monomer unit block (hereinafter "hydrogenated product (C1-1)”) was prepared as follows.
• the hydrogenation catalyst used in the hydrogenation reaction of the block copolymer was prepared by the following method.
• a nitrogen-purged reaction vessel was charged with 1 L of dried and purified cyclohexane, and 100 mmol of bis(cyclopentadienyl)titanium dichloride was added. With sufficient stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days.
• a cyclohexane solution containing 470 g of butadiene and 380 g of styrene (monomer concentration 22% by mass) was continuously supplied to the reactor at a constant rate over 60 minutes, and a second polymerization reaction was carried out.
• a cyclohexane solution containing 75 g of styrene (monomer concentration 22% by mass) was further added over 10 minutes to carry out a third polymerization reaction. Thereafter, the third polymerization reaction was stopped by adding methanol to obtain a copolymer.
• the styrene content in the obtained copolymer was 53% by mass, the styrene polymer block content in the copolymer was 15% by mass, the styrene content in the copolymer block (i.e., the copolymer block containing conjugated diene monomer units and vinyl aromatic monomer units) was 45% by mass, and the vinyl bond content was 23%.
• the resulting copolymer (block copolymer) was subsequently subjected to the hydrogenation reaction described below in (3).
• the weight-average molecular weight of the resulting hydrogenated block copolymer (C1-1) was 160,000, and the hydrogenation rate of the butadiene double bonds contained in the hydrogenated block copolymer (C1-1) was 99%.
• one of the tan ⁇ peaks obtained by viscoelasticity measurement was present at -15°C.
• D softener (hereinafter referred to as component (D))
• D-1 paraffin-based oil
• component (D′) paraffinic oil D′-1 (manufactured by Idemitsu Kosan Co., Ltd., product name “Diana Process Oil PW-100”) and paraffinic oil D′-2 (manufactured by Hansen & Rosenthal Co., Ltd., product name “Pionier 2275”) were used.
• D-1, D'-1 and D'-2 The physical properties of D-1, D'-1 and D'-2 are shown in Table 1 below.
• E Polyorganosiloxane
• component (E) dimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., trade name "SH200”; kinematic viscosity 60,000 centistokes (cSt)) (hereinafter referred to as "E-1") was used.
• crosslinking agent was mixed with the crosslinking assistant and the softener described below to form a crosslinking agent mixture, in which 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (manufactured by NOF Corporation, product name "Perhexa 25B") was used as the crosslinking agent.
• crosslinking aid polyfunctional monomer
• softener blended in the crosslinking agent are as follows:
• the amounts of the crosslinking aid and softener are based on 100 parts by mass of the crosslinking agent.
• Crosslinking aid 1 triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd.; hereinafter referred to as "TAIC")) 35 parts by mass
• Crosslinking aid 2 divininylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.; hereinafter referred to as "DVB")
• Softener manufactured by Idemitsu Kosan Co., Ltd., product name "Diana Process Oil PW-100
• the screw used was a two-thread screw having kneading sections before and after the inlet.
• thermoplastic elastomer composition was used as the evaluation sample in the physical property evaluation of "(1) Shear viscosity" above.
• thermoplastic elastomer composition was compression molded at 200° C. using a hot press (manufactured by Toho Press Manufacturing Co., Ltd., “T-50”) to produce a sheet having a thickness of 2 mm.
• the obtained sheet having a thickness of 2 mm was used as an evaluation sample for the physical property evaluation of “(2) Surface hardness (Shore-A hardness)” above.
• the obtained thermoplastic elastomer was then injection molded using an injection molding machine "M150CL-DM manufactured by Meiki Seisakusho Co., Ltd.” under conditions of a resin temperature of 250°C and a mold temperature of 40°C.
• a flat mold having a grained surface and dimensions of 15 cm length x 9 cm width x 1 mm thickness was used to obtain a molded product having an average arithmetic roughness Ra of 20 ⁇ m.
• the obtained molded product was used as an evaluation sample for the evaluation of "(3) Appearance of molded product".
• the composition of the raw materials and the results of the physical property evaluation are shown in Table 2 below.

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