JP7530195B2 - Ethylene/α-olefin/non-conjugated polyene copolymer composition and use thereof - Google Patents

Description

The present invention relates to an ethylene/α-olefin/non-conjugated polyene copolymer composition, and more specifically to an ethylene/α-olefin/non-conjugated polyene copolymer composition capable of providing a molded article having excellent heat aging resistance and engine oil barrier properties, and uses thereof.

Olefin-based thermoplastic elastomers, which are a type of thermoplastic elastomer and are obtained by crosslinking a composition of an ethylene-α-olefin-non-conjugated polyene copolymer and a crystalline olefin polymer, are lightweight and easy to recycle, and therefore are widely used as energy-saving and resource-saving thermoplastic elastomers, particularly as a replacement for vulcanized rubber, in automobile parts such as hoses, pipes, and boots (blow molded products) for automobiles (for example, Patent Documents 1 and 2).

However, while these automobile parts are always required to be made lighter to improve fuel economy, the thermoplastic elastomers used contain a lot of filler, which tends to increase the specific gravity, preventing the weight reduction of parts. Furthermore, these automobile parts are used in places that come into contact with lubricating oils and greases, but since olefin-based thermoplastic elastomers generally have low oil resistance to paraffin-based process oils, these automobile parts obtained containing olefin-based thermoplastic elastomers also have low oil resistance, and further improvement is required.

JP 2001-294714 A JP 2011-202136 A

The object of the present invention is to obtain an ethylene-α-olefin-non-conjugated polyene copolymer composition that can provide a molded article having excellent heat aging resistance and engine oil barrier properties.

The present invention relates to an ethylene-α-olefin-non-conjugated polyene copolymer (S) containing ethylene, an α-olefin having 3 or more carbon atoms, and a non-conjugated polyene as structural units, an ethylene-α-olefin-non-conjugated polyene copolymer composition characterized by containing 10 to 300 parts by mass of carbon black (L) and 0.1 to 80 parts by mass of organic short fibers (D) per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (S), and a crosslinked product of the copolymer composition.

The crosslinked product obtained by crosslinking the ethylene-α-olefin-non-conjugated polyene copolymer composition of the present invention can provide a molded article that has excellent heat aging resistance and engine oil barrier properties compared to the crosslinked products of the ethylene-α-olefin-ENB copolymer that have been widely used in the past.

Ethylene-α-olefin-non-conjugated polyene copolymer (S)
The ethylene-α-olefin-non-conjugated polyene copolymer (S) (hereinafter also referred to as "copolymer (S)") has structural units derived from ethylene (A), structural units derived from an α-olefin (B) having 3 to 20 carbon atoms, and structural units derived from a non-conjugated polyene (C). The non-conjugated polyene (C) contains, in the molecule, two or more in total of at least one partial structure selected from formulae (I) and (II).

Examples of α-olefins (B) having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. Among these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene, and 1-octene are preferred, with propylene being more preferred.

The copolymer (S) contains structural units derived from at least one type of α-olefin (B) having 3 to 20 carbon atoms, and may contain structural units derived from two or more types of α-olefins (B) having 3 to 20 carbon atoms.

Examples of the non-conjugated polyene (C) include 5-vinyl-2-norbornene (VNB), norbornadiene, 1,4-hexadiene, and dicyclopentadiene. Among these, it is preferable that the non-conjugated polyene (C) contains VNB, and it is more preferable that the non-conjugated polyene (C) is VNB, since it is highly available, has good hydrosilyl crosslinking, and tends to improve the heat resistance of the composition.

The copolymer (S) contains constitutional units derived from at least one type of non-conjugated polyene (C), and may contain constitutional units derived from two or more types of non-conjugated polyenes (C).
The copolymer (S) may further have a constituent unit derived from a non-conjugated polyene (D) containing only one partial structure selected from the formulae (I) and (II) in the molecule.

Examples of non-conjugated polyenes (D) include 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(3-butenyl)-2-norbornene, 5-(1-methyl-2-propenyl)-2-norbornene, 5-(4-pentenyl)-2-norbornene, 5-(1-methyl-3-butenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-(2,3-dimethyl-3-butenyl)-2-norbornene, 5-(2-ethyl-3-butenyl)-2-norbornene, Examples of such compounds include 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(6-heptenyl)-2-norbornene, 5-(3-methyl-5-hexenyl)-2-norbornene, 5-(3,4-dimethyl-4-pentenyl)-2-norbornene, 5-(3-ethyl-4-pentenyl)-2-norbornene, 5-(7-octenyl)-2-norbornene, 5-(2-methyl-6-heptenyl)-2-norbornene, 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(5-ethyl-5-hexenyl)-2-norbornene, and 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene. Among these, ENB is preferred because it is easily available and has good mechanical properties.

The copolymer (S) can contain constitutional units derived from at least one type of non-conjugated polyene (D), and may contain constitutional units derived from two or more types of non-conjugated polyenes (D).
As the requirement (i), in the copolymer (S), the molar ratio (structural units derived from ethylene (A)/structural units derived from an α-olefin (B) having 3 to 20 carbon atoms) is 40/60 to 99.9/0.1, preferably 50/50 to 90/10, more preferably 55/45 to 85/15, and even more preferably 55/45 to 78/22. Such a copolymer (S) is preferred because it has excellent mechanical strength and flexibility.

As requirement (ii), the content of the structural unit derived from the non-conjugated polyene (C) in 100% by mass of the copolymer (S) (i.e., 100% by mass of the total content of all structural units) is 0.07 to 10% by mass, preferably 0.1 to 8.0% by mass, and more preferably 0.5 to 5.0% by mass. Such a copolymer (S) is preferred because the crosslinked product obtained from the composition of the present invention has sufficient hardness and excellent mechanical properties, and is also preferred because it exhibits a fast crosslinking rate.

In 100% by mass of the copolymer (S), the content of the constitutional units derived from the non-conjugated polyene (D) is usually 0 to 20% by mass, and preferably 0 to 8% by mass.
The contents of the structural units derived from ethylene (A), α-olefin (B), non-conjugated polyene (C) and non-conjugated polyene (D) in the copolymer (S) can be determined by ¹³ C-NMR.

The Mooney viscosity ML ₍₁₊₄₎ of the copolymer (S) at 125° C. is preferably 5 to 100, more preferably 20 to 95, and further preferably 50 to 90. The copolymer (S) having a Mooney viscosity in the above range has good processability and flowability, exhibits excellent rubber physical properties, and also tends to exhibit good post-treatment quality (ribbon handling properties).

The Mooney viscosity was measured using a Mooney viscometer (Shimadzu Corporation, SMV202 type) according to JIS
Measured according to K6300 (1994).
The intrinsic viscosity [η] of the copolymer (S) measured in decalin at 135° C. is preferably 0.1 to 5 dL/g, more preferably 0.5 to 5.0 dL/g, and even more preferably 0.9 to 4.0 dL/g. The copolymer (S) having [η] in the above range tends to have excellent moldability.

Specifically, [η] is measured as follows. Approximately 20 mg of copolymer (S) is dissolved in 15 mL of decalin, and the specific viscosity η _sp is measured in an oil bath at 135° C. The decalin solution is diluted by adding 5 mL of decalin solvent, and the specific viscosity η _sp is measured in the same manner. This dilution operation is repeated two more times, and the value of η _sp /C when the concentration (C) is extrapolated to 0 is adopted as the limiting viscosity.
[η]=lim(η _sp /C) (C→0)

<<Method for producing ethylene-α-olefin-non-conjugated polyene copolymer (S)>>
The ethylene-α-olefin-non-conjugated polyene copolymer (S) according to the present invention is obtained by copolymerizing monomers including ethylene (A), an α-olefin (B) having 3 to 20 carbon atoms, a non-conjugated polyene (C), and, if necessary, a non-conjugated polyene (D). The copolymer (S) may be prepared by any method, but is preferably obtained by copolymerizing the monomers in the presence of a metallocene compound, and more preferably obtained by copolymerizing the monomers in the presence of a catalyst system containing a metallocene compound. Specifically, the copolymer (S) can be produced by adopting, for example, the method using a metallocene catalyst described in International Publication No. WO 2015/122495.

Carbon Black (L)
Carbon black (L), which is one of the components contained in the copolymer composition of the present invention, is a type of known rubber reinforcing agent that is compounded in rubber compositions, and is an inorganic substance generally known as carbon black.

Specific examples of carbon black (L) used in the present invention include Asahi #55G, Asahi #60G, and Asahi #60UG (all manufactured by Asahi Carbon Co., Ltd.), and Seast (V, SO, 116, 3, 6, 9, SP, TA, etc.) carbon black (manufactured by Tokai Carbon Co., Ltd.), and these carbon blacks are surface-treated with a silane coupling agent, etc.

<<Organic Short Fiber (D)>>
The organic short fiber (D), which is one of the components contained in the copolymer composition of the present invention, is not particularly limited as long as it is a fibrous organic material having an average fiber length in the range of 0.1 to 12 mm. The average fiber length of the organic short fiber (b) can be determined, for example, by taking a photograph using an optical microscope, measuring the lengths of 100 short fibers randomly selected from the obtained photograph, and calculating the arithmetic average. If the average fiber length is too short, the vibration damping properties may be insufficient. On the other hand, if the average fiber length is too long, the processability during kneading as a polymer composition may be deteriorated. The average fiber length of the organic short fiber (D) is preferably 0.3 to 10 mm, more preferably 0.5 to 6 mm.

The average fiber diameter of the organic short fibers (D) is not particularly limited, but is preferably 0.5 to 100 μm, more preferably 1 to 50 μm, and even more preferably 2 to 20 μm, since this makes the effects of the present invention more pronounced. The average fiber diameter of the organic short fibers (D) can be determined, for example, by taking a photograph using an optical microscope, measuring the diameters of the thickest parts of 100 short fibers randomly selected from the photograph, and calculating the arithmetic average. The aspect ratio of the organic short fibers (D) ("average fiber length of organic short fibers" / "average fiber diameter of organic short fibers") is not particularly limited, but is preferably 5 to 1000, and more preferably 50 to 800.

Examples of the organic short fibers (D) used in the present invention include natural fibers such as cotton and wood cellulose fibers; and fibers made of synthetic resins such as polyamide, polyester, polyvinyl alcohol, rayon, polyparaphenylene benzobisoxazole, polyethylene, polypropylene, polyarylate, polyimide, polyphenylene sulfide, polyether ether ketone, polylactic acid, polycaprolactone, polybutylene succinate, and fluorine-based polymers. Among these, it is preferable to use short fibers made of synthetic resins, and it is more preferable to use short fibers made of polyamide, since the effects of the present invention are more pronounced.

Examples of polyamides include aliphatic polyamides such as polycapramide, poly-ω-aminoheptanoic acid, poly-ω-aminononanoic acid, polyundecaneamide, polyethylenediamineadipamide, polytetramethyleneadipamide, polyhexamethyleneadipamide, polyhexamethylenesebacamide, polyhexamethylenedodecamamide, polyoctamethyleneadipamide, and polydecamethyleneadipamide; polyparaphenyleneterephthalamide (trade name "Kevlar", manufactured by DuPont-Toray Co., Ltd.) (trade name "Twaron", manufactured by Teijin Limited), polymetaphenylene isophthalamide (trade name "Conex", manufactured by Teijin Limited), copolyparaphenylene-3,4'-oxydiphenylene terephthalamide (trade name "Technora", manufactured by Teijin Limited), aromatic polyamides (aramids) such as polymetaxylylene adipamide, polymetaxylylene pimelamide, polymetaxylylene azelamide, polyparaxylylene azelamide, and polyparaxylylene decanamide; and the like. Among these, aromatic polyamides, i.e., aramids, are preferred because they can further improve vibration damping properties, with polyparaphenylene terephthalamide, polymetaphenylene isophthalamide, and copolyparaphenylene-3,4'oxydiphenylene-terephthalamide being more preferred, and copolyparaphenylene-3,4'oxydiphenylene-terephthalamide being particularly preferred.

That is, as the short fibers made of polyamide, aramid short fibers are preferable, polyparaphenylene terephthalamide short fibers, polymetaphenylene isophthalamide short fibers and copolyparaphenylene-3,4'oxydiphenylene-terephthalamide short fibers are more preferable, and copolyparaphenylene-3,4'oxydiphenylene-terephthalamide short fibers are particularly preferable.

The organic short fibers (D) may be in the form of chopped fibers (cut fibers) or pulp having fibrils, and may be treated with various adhesives such as epoxy adhesives, isocyanate adhesives, and resorcinol-formaldehyde resin/latex.

<Fatty acid amide (M)>
The fatty acid amide (M), which is one of the components that may be contained in the copolymer composition of the present invention, is an amide of a higher fatty acid, and specific examples thereof include monoamides of higher fatty acids such as stearamide, oxystearamide, oleylamide, erucic acid amide, laurylamide, palmitylamide, behenamide, and methylolamide; diamides of higher fatty acids such as methylene bis-stearamide, ethylene bis-stearamide, ethylene bis-oleylamide, and ethylene bis-laurylamide; complex amides of higher fatty acids such as stearyl oleylamide, N-stearyl erucamide, and N-oleyl palmitamide; and special fatty acids commercially available under the trade names Plastrodin ^™ (manufactured by Fujisawa Pharmaceutical Co., Ltd.) and Plastrodin S ^™ (manufactured by Fujisawa Pharmaceutical Co., Ltd.).

<Ethylene/α-olefin/non-conjugated polyene copolymer composition>
The copolymer composition of the present invention contains the above-mentioned copolymer (S), 10 to 300 parts by mass, preferably 30 to 200 parts by mass, and more preferably 50 to 180 parts by mass of the above-mentioned carbon black (L), and 0.1 to 80 parts by mass, preferably 0.2 to 50 parts by mass, and more preferably 0.3 to 30 parts by mass of the above-mentioned organic short fibers (D), relative to 100 parts by mass of the copolymer (S).

The copolymer composition of the present invention contains the carbon black (L) and the organic short fibers (D) in the above-mentioned ranges, so that the obtained molded article has good rigidity and excellent oil resistance.
The copolymer composition of the present invention may contain, in addition to the carbon black (L) and the organic short fibers (D), a fatty acid amide (M) in an amount of 0.1 to 10 parts by mass, preferably 0.2 to 8 parts by mass, and more preferably 0.5 to 6 parts by mass.

In addition to the copolymer (S), carbon black (L), organic short fiber (D), and fatty acid amide (M), the copolymer composition of the present invention may contain other components as necessary within a range that does not impair the effects of the present invention. Examples of other components include polymers, crosslinking agents, crosslinking assistants, vulcanization accelerators, vulcanization assistants, and inorganic fillers. At least one selected from softeners, antiaging agents (stabilizers), processing assistants, activators, moisture absorbents, heat stabilizers, weather stabilizers, antistatic agents, colorants, lubricants, and thickeners may be contained. Each polymer and additive may be used alone or in combination of two or more. Also, known foaming agents, foaming assistants, colorants, dispersants, flame retardants, and the like may be used as other components as necessary.

<Crosslinking Agent, Crosslinking Coagent, Vulcanization Accelerator, and Vulcanization Coagent>
Examples of the crosslinking agent include crosslinking agents generally used when crosslinking rubber, such as organic peroxides, phenolic resins, sulfur-based compounds, hydrosilicone-based compounds, amino resins, quinones or derivatives thereof, amine-based compounds, azo-based compounds, epoxy-based compounds, isocyanate-based compounds, etc. Among these, organic peroxides and sulfur-based compounds (hereinafter also referred to as "vulcanizing agents") are preferred.

Examples of organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)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-butylperoxybenzoate, ert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

When an organic peroxide is used as the crosslinking agent, the amount of the organic peroxide in the copolymer composition is generally 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of copolymer (S). When the amount of the organic peroxide is within the above range, the copolymer composition exhibits excellent crosslinking properties without blooming on the surface of the resulting molded article, which is preferable.

When an organic peroxide is used as the crosslinking agent, it is preferable to use a crosslinking assistant in combination. Examples of crosslinking assistants include sulfur; quinone dioxime crosslinking assistants such as p-quinone dioxime; acrylic crosslinking assistants such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyl crosslinking assistants such as diallyl phthalate and triallyl isocyanurate; maleimide crosslinking assistants; divinylbenzene; and metal oxides such as zinc oxide (e.g., ZnO#1 and zinc oxide type 2 (JIS standard (K-1410)), manufactured by Hakusui Tech Co., Ltd.), magnesium oxide, and activated zinc oxide (e.g., zinc oxide such as "META-Z102" (trade name; manufactured by Inoue Seki Kogyo Co., Ltd.)).

When a crosslinking aid is used, the amount of the crosslinking aid in the copolymer composition is usually 0.5 to 10 moles, preferably 0.5 to 7 moles, and more preferably 1 to 6 moles, per mole of organic peroxide.

Examples of sulfur-based compounds (vulcanizing agents) include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dithiocarbamate.

When a sulfur-based compound is used as a crosslinking agent, the amount of the sulfur-based compound in the copolymer composition is usually 0.1 to 10 parts by mass, preferably 0.2 to 7.0 parts by mass, and more preferably 0.5 to 5.0 parts by mass, per 100 parts by mass of copolymer (S). When the amount of the sulfur-based compound is within the above range, there is no bloom on the surface of the obtained molded article, and the copolymer composition exhibits excellent crosslinking properties.

When a sulfur-based compound is used as a crosslinking agent, it is preferable to use a vulcanization accelerator in combination.
Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole (e.g., Suncerer M (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), 2-(4-morpholinodithio)benzothiazole (e.g., Noccelaer MDB-P (trade name; manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-dinitrophenyl)mercaptobenzothiazole, Thiazole-based vulcanization accelerators such as ethyl-4-morpholinothio)benzothiazole and dibenzothiazyl disulfide (for example, Sancerer DM (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); guanidine-based vulcanization accelerators such as diphenyl guanidine, triphenyl guanidine and diorthotolyl guanidine; aldehyde amine-based vulcanization accelerators such as acetaldehyde-aniline condensate and butyraldehyde-aniline condensate; imidazoline-based vulcanization accelerators such as 2-mercaptoimidazoline; tetramethylthiuram monosulfide (for example, Sancerer DM (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (e.g., Sancerer TS (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetramethylthiuram disulfide (e.g., Sancerer TT (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetraethylthiuram disulfide (e.g., Sancerer TET (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetrabutylthiuram disulfide (e.g., Sancerer TBT (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)) and dipentamethylenethiuram tetrasulfide (e.g., Sancerer TRA (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); zinc dimethyldithiocarbamate, diethyldithio Examples of the vulcanization accelerator include dithioacid salt vulcanization accelerators such as zinc carbamate, zinc dibutyldithiocarbamate (for example, Sanseller PZ, Sanseller BZ, and Sanseller EZ (trade names; manufactured by Sanshin Chemical Industry Co., Ltd.)) and tellurium diethyldithiocarbamate; thiourea vulcanization accelerators such as ethylenethiourea (for example, Sanseller BUR (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.), Sanseller 22-C (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), N,N'-diethylthiourea, and N,N'-dibutylthiourea; and xanthate vulcanization accelerators such as zinc dibutylxatogenate.

When a vulcanization accelerator is used, the blending amount of the vulcanization accelerator in the copolymer composition is generally 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of copolymer (S). When the blending amount of the vulcanization accelerator is within the above range, the copolymer composition exhibits excellent crosslinking properties without blooming on the surface of the obtained molded article. When a sulfur-based compound is used as the crosslinking agent, a vulcanization assistant can be used in combination.

Examples of the vulcanization aid include zinc oxide (e.g., ZnO#1 and zinc oxide type 2, manufactured by Hakusui Tech Co., Ltd.), magnesium oxide, and activated zinc oxide (e.g., zinc oxide such as "META-Z102" (trade name; manufactured by Inoue Seki Kogyo Co., Ltd.)).
When a vulcanization aid is used, the blending amount of the vulcanization aid in the ethylene copolymer composition is usually 1 to 20 parts by mass based on 100 parts by mass of the copolymer (S).

<Softener>
Specific examples of the softener according to the present invention include petroleum-based softeners such as process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, Vaseline, liquid ethylene-propylene copolymer, and liquid ethylene-1-butene copolymer; coal tar-based softeners such as coal tar; fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; waxes such as beeswax and carnauba wax; and fatty acids or salts thereof such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, and calcium stearate. naphthenic acid, pine oil, rosin or derivatives thereof; synthetic polymeric substances such as terpene resin, petroleum resin, coumarone-indene resin, etc.; ester-based softeners such as dioctyl phthalate, dioctyl adipate, etc.; and others such as microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricating oil, tall oil, and sub(factice), with petroleum-based softeners being preferred, and liquid ethylene-propylene copolymer, liquid ethylene-1-butene copolymer, and process oil being particularly preferred.

These softeners may be used alone or in combination of two or more.
The amount of the softener in the copolymer composition is generally 2 to 100 parts by mass, preferably 10 to 100 parts by mass, based on 100 parts by mass of the copolymer (S).

<Inorganic fillers>
Specific examples of the inorganic filler according to the present invention include light calcium carbonate, heavy calcium carbonate, talc, clay, and the like, and one or more of these are used. Among these, heavy calcium carbonate such as "Whiten SB" (product name; Shiraishi Calcium Co., Ltd.) is preferred.

When the copolymer composition contains an inorganic filler, the amount of the inorganic filler is usually 2 to 50 parts by mass, preferably 5 to 50 parts by mass, per 100 parts by mass of copolymer S). When the amount is within the above range, the copolymer composition has excellent kneading processability.

<Anti-aging agent (stabilizer)>
The copolymer composition according to the present invention can be blended with an antioxidant (stabilizer) to extend the life of a molded article formed therefrom. Examples of such antioxidants include conventionally known antioxidants, such as amine-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants.

Further examples of antioxidants include aromatic secondary amine antioxidants such as phenylbutylamine and N,N-di-2-naphthyl-p-phenylenediamine; phenolic antioxidants such as dibutylhydroxytoluene and tetrakis[methylene(3,5-di-t-butyl-4-hydroxy)hydrocinnamate]methane; thioether antioxidants such as bis[2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl]sulfide; dithiocarbamate antioxidants such as nickel dibutyldithiocarbamate; and sulfur-based antioxidants such as 2-mercaptobenzoylimidazole, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, dilaurylthiodipropionate, and distearylthiodipropionate.

These antioxidants can be used alone or in combination of two or more, and the amount of the antioxidant is usually 0.3 to 10 parts by mass, and preferably 0.5 to 7.0 parts by mass, per 100 parts by mass of copolymer (S). By keeping the amount within this range, no blooming occurs on the surface of the molded article obtained from the crosslinked product of the copolymer composition, and furthermore, the occurrence of crosslinking inhibition can be suppressed.

<Processing aids>
As the processing aid according to the present invention, a wide variety of processing aids that are generally compounded with rubber can be used.

Specific examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, esters, etc. Of these, stearic acid is preferred.
The amount of the processing aid to be blended is usually 10 parts by mass or less, and preferably 8.0 parts by mass or less, based on 100 parts by mass of the copolymer (S) contained in the copolymer composition.

<Activator>
Specific examples of the surfactant include amines such as di-n-butylamine, dicyclohexylamine, and monoethanolamine; surfactants such as diethylene glycol, polyethylene glycol, lecithin, triaryl methylate, and zinc compounds of aliphatic carboxylic acids or aromatic carboxylic acids; zinc peroxide preparations; octadecyltrimethylammonium bromide, synthetic hydrotalcite, and special quaternary ammonium compounds.
When an activator is contained, the amount of the activator is usually 0.2 to 10 parts by mass, preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the copolymer (S).

Moisture absorbent
Specific examples of the moisture absorbent include calcium oxide, silica gel, sodium sulfate, molecular sieve, zeolite, and white carbon.
When the moisture absorbent is contained, the blending amount thereof is usually 0.5 to 15 parts by mass, preferably 1.0 to 12 parts by mass, based on 100 parts by mass of the copolymer (S).

<Crosslinked Product of Copolymer Composition>
The crosslinked product of the copolymer composition of the present invention is obtained by crosslinking the above-mentioned copolymer composition of the present invention.
In order to crosslink the copolymer composition of the present invention, a crosslinking agent such as an organic peroxide is blended with the copolymer composition, and then crosslinking is carried out.

As a method for crosslinking the copolymer composition of the present invention, the copolymer composition is mixed with the organic peroxide, etc., and then a conventionally known kneading device, such as an open-type mixing roll, a non-open-type Banbury mixer, an extruder, a kneader, a continuous mixer, etc., is used. Among these, a non-open-type kneading device is preferred, and kneading is preferably performed under an atmosphere of an inert gas such as nitrogen gas or carbon dioxide gas.

<<Uses of the copolymer composition>>
The copolymer composition of the present invention can be molded by a commonly used molding method such as injection molding, extrusion molding, blow molding, compression molding, and the like. It is used in a wide range of applications, including automotive parts (weather strips, ceiling materials, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, handbrake grips, shift knob covers, seat adjustment knobs, flapper door seals, wire harness grommets, rack and pinion boots, suspension cover boots, glass guides, inner belt line seals, roof guides, trunk lid seals, molded quarter window gaskets, corner moldings, glass encapsulations, hood seals, glass run channels, secondary seals, clean side ducts, various gaskets, etc.), civil engineering and building material parts (waterstop materials, joint materials, architectural window frames, etc.), sporting goods (golf clubs, tennis racket grips, etc.), industrial parts (hose tubes, gaskets, etc.), home appliance parts (hoses, gaskets, etc.), medical equipment parts, electric wires, and miscellaneous goods.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.
The ethylene/α-olefin/non-conjugated polyene copolymers (S) used in the examples and comparative examples are shown below.

Production Example 1 Production of Ethylene/α-olefin/vinylnorbornene Copolymer (S-1) Ethylene/propylene/5-vinyl-2-norbornene (VNB) copolymer (S-1) was produced using a continuous polymerization apparatus as follows.

A 300-liter polymerization reactor was continuously fed with 58.3 L/hr of dehydrated hexane solvent through line 1, and 4.5 mmol/hr of triisobutylaluminum (TiBA), 0.150 mmol/hr of (C ₆ H ₅ ) ₃ CB(C ₆ F ₅ ) ₄ , and 0.030 mmol/hr of di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride through line 2. At the same time, 6.6 kg/hr of ethylene, 9.3 kg/hr of propylene, 18 L/hr of hydrogen, and 340 g/hr of VNB were continuously fed into the polymerization reactor through separate lines, and copolymerization was carried out under the conditions of a polymerization temperature of 87° C., a total pressure of 1.6 MPaG, and a residence time of 1.0 hour.

The ethylene-propylene-VNB copolymer solution produced in the polymerization reactor was continuously discharged at a flow rate of 88.0 L/hr, heated to 170°C (pressure increased to 4.1 MPaG), and supplied to a phase separator. At this time, ethanol, a polymerization inhibitor, was continuously introduced into the discharge line in an amount of 0.1 mol times the amount of TiBA in the liquid component extracted from the polymerization reactor.

In the phase separator, the ethylene-propylene-VNB copolymer solution was separated into a dense phase (lower phase) containing most of the ethylene-propylene-VNB copolymer and a dilute phase (upper phase) containing a small amount of polymer.

The separated thick phase was introduced into heat exchanger K at 85.4 liters/hr, and then into a hopper where the solvent was evaporated and separated, yielding ethylene-propylene-VNB copolymer at a rate of 7.8 kg/hr.

The physical properties of the copolymer (S-1) obtained were measured by the method described above. The Mooney viscosity ML ₍₁₊₄₎ 125°C of the copolymer (S-1) was 69, the molar ratio (ethylene unit/propylene unit) was 70/30, the content of VNB units was 1.4 mass%, and the intrinsic viscosity [η] measured in decalin at 135°C was 2.8 dL/g. The molecular weight distribution of the copolymer (S-1) obtained was bimodal.

[Production Example 2]
<Polymerization example of softener component>
The polymerization of the softener component was carried out in a 300 L SUS reactor equipped with a stirrer, with the temperature kept at 80°C, the liquid level at 100 L, and the rates of hexane, ethylene, propylene, and hydrogen at 52.0 kg/h, 12.0 kg/h, 7.7 kg/h, and 1600 NL/h, respectively, using 0.09 mmol/h of [N-(1,1-dimethylethyl)-1,1-dimethyl-1-[(1,2,3,3A,8A-η)-1,5,6,7-tetrahydro-2-methyl-S-indacene-1-yl]silane aminate(2-)-κN][(1,2,3,4-η)-1,3-pentadiene]-titanium as the main catalyst and (C ₆ H ₅ ) ₃ CB(C ₆ F ₅ ) as the cocatalyst. The reactor was continuously fed with 0.36 mmol of ₄ per hour and 2.0 mmol of TIBA as an organoaluminum compound per hour to obtain a polymerization solution of ethylene and propylene copolymer (softener component). The main catalyst was synthesized according to the method described in WO 98/49212. The softener component was obtained from the obtained polymerization solution by flash drying. The molar ratio (ethylene unit/propylene unit) of the softener was 70/30, and the intrinsic viscosity [η] measured in decalin at 135°C was 0.2 dL/g.

[Physical Properties of Uncrosslinked Copolymer Composition]
(Mooney Viscosity (ML(1+4)100°C))
The Mooney viscosity at 100°C (ML(1+4)100°C) was measured at 100°C using a Mooney viscometer (SMV202 model, manufactured by Shimadzu Corporation) in accordance with JIS K6300.

<Physical properties of molded body (crosslinked product)>
(Tensile stress at break, tensile elongation at break)
The tensile stress at break and the tensile elongation at break of the sheet were measured by the following method.

The sheet was punched out to prepare No. 3 dumbbell test pieces as described in JIS K 6251 (1993). Using these test pieces, tensile tests were carried out according to the method specified in JIS K6251, paragraph 3, at a measurement temperature of 25°C and a tensile speed of 500 mm/min, and the modulus at 25% elongation (M25), modulus at 100% elongation (M100), tensile stress at break (TB), and tensile elongation at break (EB) were measured.

(Durometer A hardness)
In accordance with JIS K 6253, the sheet hardness (type A durometer, HA) was measured using six 2 mm sheet-like molded products having smooth surfaces, with the flat parts stacked to a thickness of about 12 mm.

(Oil resistance)
A crosslinked sheet having a thickness of 2 mm (length 20 mm × width 20 mm) was immersed in Nissan Engine Oil SN Strong Save X-OW20 (trade name) at 150° C. for 72 hours, and the volume change rate (ΔV) was calculated from the volume before and after immersion, and the weight change rate (ΔW) was calculated from the weight before and after immersion.
ΔV=(V2-V1)/V1×100, where V1=volume before test (cm ³ ), V2=volume after test (cm ³ )
ΔW = (W2 - W1) / W1 x 100 W1 = weight before test (g), W2 = weight after test (g)

(Heat aging resistance)
The sheet was subjected to a heat aging test in which the sheet was held at 180° C. for 168 hours in accordance with JIS K 6257. The hardness, tensile stress at break, and tensile elongation at break of the sheet after the heat aging test were measured in the same manner as in the above items [Hardness (Durometer-A)] and [Modulus, tensile stress at break, and tensile elongation at break].

Example 1
Using a MIXTRON BB MIXER (manufactured by Kobe Steel, BB-4 type, volume 2.95 L, rotor 4WH), 100 parts by mass of the copolymer (S-1) obtained in Production Example 1 and 100 parts by mass of the copolymer (S-1) were mixed with 115 parts by mass of the softener (a mixture containing 15 parts by mass of liquid ethylene-propylene copolymer) obtained in Production Example 2, and 5 parts by mass of active zinc oxide (product name: Meta Z102, manufactured by Inoue Lime Industries Co., Ltd.) as a crosslinking aid, 2 parts by mass of stearic acid as a processing aid, 1 part by mass of a phenol-based antioxidant (product name: Irganox 1010, BASF Japan Co., Ltd.) as an antiaging agent, 2 parts by mass of 2-mercaptobenzimidazole (product name: Sandant MB, manufactured by Sanshin Chemical Industry Co., Ltd.) as an antiaging agent, and a fatty acid amide (product name: Struktol WB16: calcium soap & saturated fatty acid amide mixture) as a lubricant. 2 parts by mass of carbon black (trade name Asahi #60UG, manufactured by Asahi Carbon Co., Ltd.), 138 parts by mass of carbon black (trade name Asahi #60UG, manufactured by Asahi Carbon Co., Ltd.), 77 parts by mass of paraffin-based process oil (trade name Diana Process Oil PW-380, manufactured by Idemitsu Kosan Co., Ltd.) as a softener, and 3 parts by mass of organic short fibers (D) having a fiber length of 3.5 mm (trade name Kevlar DCF, manufactured by DuPont-Toray Co., Ltd.) were blended and kneaded to obtain Blend 1.

The kneading conditions for preparing Compound 1 were a rotor rotation speed of 50 rpm, a floating weight pressure of 3 kg/cm ² , a kneading time of 5 minutes, and a kneading discharge temperature of 170°C.
The Mooney viscosity ML ₍₁₊₄₎ 100°C of Blend 1 was measured using a Mooney viscometer (Shimadzu Corporation, Model SMV202) in accordance with JIS K6300 (1994).

Next, after confirming that the temperature of Compound 1 had reached 40°C, 12.5 parts by mass of dicumyl peroxide (trade name: Parkmil D-40 (dicumyl peroxide 40% by mass), manufactured by Nippon Oil & Fats Co., Ltd.) as a crosslinking agent and 3 parts by mass of trimethylolpropane trimethacrylate (trade name: Hi-Cross M, manufactured by Seiko Chemical Co., Ltd.) as a crosslinking aid were added to Compound 1 and kneaded using a 6-inch roll to obtain Compound 2.

The kneading conditions for preparing compound 2 were: roll temperature front roll/rear roll = 50°C/50°C, roll peripheral speed front roll/rear roll = 18 rpm/15 rpm, roll gap 2 mm, and kneading time 8 minutes to obtain compound 2.

Formulation 2 was pressed at 170° C. for 10 minutes using a press molding machine to produce a crosslinked sheet having a thickness of 2 mm. The physical properties of the resulting crosslinked sheet were evaluated by the methods described above.
The evaluation results are shown in Table 1.

Example 2
Instead of the blend 2 used in Example 1,
The procedure of Example 1 was repeated except that ethylene glycol dimethacrylate (trade name: Sun-Ester EG, manufactured by Sanshin Chemical Industry Co., Ltd.) was used instead, to obtain a crosslinked sheet, and its physical properties were evaluated by the methods described above.
The evaluation results are shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was carried out except that the organic short fibers were not blended, to obtain a crosslinked sheet, and the physical properties were evaluated by the methods described above.
The evaluation results are shown in Table 1.

Claims (6)

An ethylene/α-olefin/non-conjugated polyene copolymer (S) containing ethylene, an α-olefin having 3 or more carbon atoms, and a non-conjugated polyene as structural units, and containing 10 to 300 parts by mass of carbon black (L) and 0.1 to 3 parts by mass of organic short fibers (D) relative to 100 parts by mass of the ethylene/α-olefin/non-conjugated polyene copolymer (S),
The organic short fibers (D) are polyparaphenylene terephthalamide short fibers, polymetaphenylene isophthalamide short fibers, or copolyparaphenylene-3,4'-oxydiphenylene-terephthalamide short fibers,
The average fiber diameter of the organic short fibers (D) is 2 to 100 μm,
The ethylene/α-olefin/non-conjugated polyene copolymer composition, characterized in that the ethylene/α-olefin/non-conjugated polyene copolymer (S) has a Mooney viscosity ML ₍₁₊₄₎ at 125°C in the range of 50 to 100 . The ethylene/α-olefin/non-conjugated polyene copolymer composition according to claim 1, further comprising 0.1 to 10 parts by mass of a fatty acid amide (M). The ethylene/α-olefin/non-conjugated polyene copolymer composition according to claim 1 or 2 , characterized in that the ethylene/α-olefin/non-conjugated polyene copolymer (S) is an ethylene/α-olefin/non-conjugated polyene copolymer (S) that satisfies the following requirements (i) to (iii):
(i) The molar ratio (structural units derived from ethylene (A)/structural units derived from an α-olefin having 3 to 20 carbon atoms (B)) is 40/60 to 99.9/0.1.
(ii) The content of constituent units derived from the non-conjugated polyene (C) is in the range of 0.07 to 10 mass %.
(iii ) The intrinsic viscosity [η] measured in decalin at 135° C. is in the range of 0.1 to 5 dL/g. The ethylene/α-olefin/non-conjugated polyene copolymer composition according to any one of claims 1 to 3, wherein the α-olefin having 3 or more carbon atoms is propylene. A crosslinked molded article formed from the ethylene-α-olefin-non-conjugated polyene copolymer composition according to any one of claims 1 to 4. A clean side duct having the cross-linked molded article according to claim 5.