Compositions for power transmission belts, molded articles, crosslinked molded articles, and power transmission belts

Abstract

To provide a transmission belt composition that has excellent processability, a modulus suitable for transmission belts, and can form a transmission belt with excellent wear resistance. [Solution] A transmission belt composition comprising an ethylene-α-olefin-non-conjugated polyene copolymer (S1) having structural units derived from ethylene [A1], structural units derived from α-olefin [B1] having 3 to 20 carbon atoms, structural units derived from a non-conjugated polyene [C1] containing a total of one substructure selected from the group consisting of the following general formulas (I) and (II) in one molecule, and structural units derived from a non-conjugated polyene [C2] containing a total of two or more substructures selected from the group consisting of the following general formulas (I) and (II) in one molecule, carbon black (B), and short fibers (C). JPEG2026092275000006.jpg25130

Description

[Technical Field]

[0001] The present invention relates to a composition for power transmission belts, a molded article, a crosslinked molded article, and a power transmission belt. [Background technology]

[0002] Power transmission belts are widely used in automobiles, motorcycles, and general industrial machinery. These belts require high rubber elasticity and abrasion resistance. Chloroprene rubber is typically used to manufacture power transmission belts that meet these properties. However, in response to the need for improved heat and cold resistance, as well as weight reduction, the use of ethylene-α-olefin-non-conjugated polyene copolymer rubber instead of chloroprene rubber is being considered (see, for example, Patent Documents 1-2).

[0003] A composition containing an ethylene-propylene-non-conjugated polyene copolymer has been disclosed as a suitable composition for transmission belts that have excellent heat resistance and abrasion resistance (Patent Document 3). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2001-310951 [Patent Document 2] Japanese Patent Publication No. 2012-215212 [Patent Document 3] Japanese Patent Publication No. 2021-042316 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, it has been found that conventional power transmission belt compositions are not necessarily sufficient in terms of achieving both processability and wear resistance of power transmission belts formed from these compositions.

[0006] The object of the present invention is to provide a composition for power transmission belts that has excellent processability, a modulus (tensile stress) suitable for power transmission belts, and excellent wear resistance, and that can form such power transmission belts. [Means for solving the problem]

[0007] The inventors of the present invention have diligently studied to solve the above problems and have found that the above problems can be solved according to the following embodiments, and have completed the present invention. Embodiments of the present invention are shown below.

[0008] [1] An ethylene-α-olefin-non-conjugated polyene copolymer (S1) having a structural unit derived from ethylene [A1], a structural unit derived from an α-olefin [B1] having 3 to 20 carbon atoms, a structural unit derived from a non-conjugated polyene [C1] containing a total of one substructure selected from the group consisting of the following general formulas (I) and (II) in one molecule, and a structural unit derived from a non-conjugated polyene [C2] containing a total of two or more substructures selected from the group consisting of the following general formulas (I) and (II) in one molecule, Carbon black (B) and, A composition for power transmission belts containing short fibers (C).

[0009] [ka]

[0010] [2] The transmission belt composition according to item [1], wherein the copolymer (S1) satisfies the following requirements (1) and (2): (1) The molar ratio [[A1] / [B1]] of structural units derived from ethylene [A1] to structural units derived from α-olefin [B1] is 50 / 50 to 85 / 15; (2) The molar ratio ([C1] / [C2]) of structural units derived from non-conjugated polyene [C1] to structural units derived from non-conjugated polyene [C2] is 85 / 15 to 99.5 / 0.5.

[0011] [3] The transmission belt composition according to item [1] or [2], wherein the copolymer (S1) satisfies the following requirement (3): (3) It satisfies the following formula (I). Log{η * (0.01)} / Log{η * (10)} > 0.0753 × {apparent iodine value derived from non-conjugated polyene [C2]} + 1.32 …(I) (In the formula, η * (0.01) represents the viscosity (Pa·sec) at 0.01 rad / sec at 190°C, and η * (10) represents the viscosity (Pa·sec) at 10 rad / sec at 190°C.)

[0012] [4] The transmission belt composition according to any one of items [1] to [3], wherein the structural unit derived from the α-olefin [B1] contains a structural unit derived from propylene.

[0013] [5] The transmission belt composition according to any one of items [1] to [4], wherein the structural unit derived from the non-conjugated polyene [C1] contains a structural unit derived from 5-ethylidene-2-norbornene (ENB).

[0014] [6] The transmission belt composition according to any one of items [1] to [5], wherein the structural unit derived from the non-conjugated polyene [C2] contains a structural unit derived from 5-vinyl-2-norbornene.

[0015] [7] The transmission belt composition according to any one of items [1] to [6], wherein the content of the short fiber (C) is 0.1 to 100 parts by mass with respect to 100 parts by mass of the copolymer (S1). [8] The transmission belt composition according to any one of items [1] to [7], wherein the short fiber (C) is an aramid short fiber.

[0016] [9] The transmission belt composition according to any one of items [1] to [8], wherein the Mooney viscosity ML(1+4) at 100°C of the copolymer (S1) is 5 to 150.

[10] A transmission belt composition according to any one of items [1] to [9], further comprising a crosslinking agent (D).

[0017]

[11] A transmission belt composition according to any one of items [1] to [9], further containing 0.1 to 20 parts by mass of a processing aid (F) per 100 parts by mass of the copolymer (S1).

[12] The transmission belt composition according to item

[10] , further comprising a crosslinking agent (E).

[0018]

[13] A molded article formed from a transmission belt composition described in any one of items [1] to

[12] .

[14] A transmission belt having the molded body described in item

[13] .

[0019]

[15] A crosslinked molded article formed from any one of the transmission belt compositions described in item [1] to

[12] .

[16] A transmission belt having a crosslinked molded body as described in item

[15] . [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a transmission belt composition that can form a transmission belt that has excellent processability, a modulus (tensile stress) suitable for transmission belts, and excellent wear resistance. [Modes for carrying out the invention]

[0021] The present invention will be described in detail below.

[0022] [Composition for power transmission belts] The transmission belt composition of the present invention (hereinafter also referred to as "this composition") comprises an ethylene-α-olefin-non-conjugated polyene copolymer (S1), carbon black (B), and short fibers (C), as described below.

[0023] <Ethylene-α-olefin-nonconjugated polyene copolymer (S1)> This composition contains an ethylene-α-olefin-non-conjugated polyene copolymer (S1) (hereinafter also referred to as "polymer (S1)"). Copolymer (S1) has structural units derived from ethylene [A1], structural units derived from α-olefin [B1] having 3 to 20 carbon atoms, structural units derived from a non-conjugated polyene [C1] containing a total of one substructure selected from the group consisting of the following general formulas (I) and (II) in one molecule, and structural units derived from a non-conjugated polyene [C2] containing a total of two or more substructures selected from the group consisting of the following general formulas (I) and (II) in one molecule.

[0024] [ka]

[0025] (α-olefin[B1]) Examples of the α-olefin [B1] include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-tetradecene, 1-hexadecene, 1-nonadecene, 1-eicosene, etc., which have a linear structure without side chains; and 4-methyl-1-pentene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc., which have side chains. Among these, propylene, 1-butene, 1-hexene, and 1-octene are preferred, 1-butene or propylene are more preferred, and propylene is particularly preferred. Such α-olefins are preferred because their raw material costs are relatively low and the resulting rubber molded articles exhibit excellent mechanical properties.

[0026] The α-olefin [B1] may be used alone or in combination of two or more types. That is, the copolymer (S1) contains at least one structural unit derived from α-olefin [B1] having 3 to 20 carbon atoms, and may contain two or more structural units derived from α-olefin [B1] having 3 to 20 carbon atoms.

[0027] (Unconjugated polyene [C1]) The non-conjugated polyene [C1] includes 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, and 5-(2-ethyl-3-butenyl). Examples include 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 readily available, the crosslinking rate during crosslinking with organic peroxides is easy to control, and good mechanical properties are easily obtained.

[0028] The non-conjugated polyene [C1] may be used alone or in combination of two or more. That is, the copolymer (S1) contains constituent units derived from at least one component [C1], and may contain constituent units derived from two or more components [C1].

[0029] (Unconjugated polyene [C2]) Examples of the non-conjugated polyene [C2] include 5-vinyl-2-norbornene (VNB), norbornadiene, 1,4-hexadiene, and dicyclopentadiene. Among these, VNB is preferred due to its high availability, good crosslinking with organic peroxides, and ease with which the heat resistance of the composition can be improved.

[0030] The non-conjugated polyene [C2] may be used alone or in combination of two or more. That is, the copolymer (S1) contains structural units derived from at least one component [C2], and may contain structural units derived from two or more components [C2].

[0031] Each copolymer (S1) may contain at least one biomass-derived monomer (ethylene [A1], α-olefin with 3 to 20 carbon atoms [B1], non-conjugated polyene [C1], non-conjugated polyene [C2]). Examples of biomass-derived α-olefins include biomass-derived propylene. Examples of biomass-derived non-conjugated polyenes [C1] include biomass-derived 5-ethylidene-2-norbornene, and examples of biomass-derived non-conjugated polyenes [C2] include biomass-derived 5-vinyl-2-norbornene. The monomers used as raw materials for copolymer (S1) may contain only biomass-derived monomers, or they may contain both biomass-derived monomers and fossil fuel-derived monomers. Biomass-derived monomers such as biomass-derived ethylene, biomass-derived α-olefins, and biomass-derived non-conjugated polyenes can be obtained by known methods. It is preferable for copolymer (S1) to contain constituent units derived from biomass-derived monomers from the viewpoint of reducing environmental impact.

[0032] Each copolymer (S1) may contain at least one constituent unit derived from chemically recycled monomers. The chemically recycled monomers used as raw materials for copolymer (S1) may be chemically recycled ethylene, chemically recycled α-olefins, or chemically recycled non-conjugated polyenes. Furthermore, the monomers used as raw materials for copolymer (S1) may consist solely of chemically recycled monomers, or may consist of both chemically recycled monomers and fossil fuel-derived monomers. Chemically recycled monomers such as chemically recycled ethylene, chemically recycled α-olefins, and chemically recycled non-conjugated polyenes can be obtained by known methods. It is preferable for copolymer (S1) to contain constituent units derived from chemically recycled monomers from the viewpoint of reducing environmental impact (mainly waste reduction).

[0033] The copolymer (S1) preferably satisfies the following requirements (1) and (2). 《Requirement (1)》 Requirement (1) is that the molar ratio [[A1] / [B1]] of structural units derived from ethylene [A1] to structural units derived from α-olefins [B1] having 3 to 20 carbon atoms is 50 / 50 to 85 / 15. Copolymers (S1) with a molar ratio within the above range exhibit an excellent balance between rubber elasticity at low temperatures and tensile stress at room temperature.

[0034] The lower limit of the above molar ratio [[A1] / [B1]] is preferably 52 / 48, more preferably 54 / 46, and even more preferably 55 / 45. The upper limit of the above molar ratio [[A1] / [B1]] is preferably 80 / 20, more preferably 75 / 25, and even more preferably 70 / 30. The molar ratio [[A1] / [B1]] is, 1 It can be measured using H-NMR spectroscopy, etc.

[0035] Requirements (2) Requirement (2) is that the molar ratio ([C1] / [C2]) of structural units derived from non-conjugated polyene [C1] to structural units derived from non-conjugated polyene [C2] is 85 / 15 to 99.5 / 0.5. The molar ratio is preferably 90 / 10 to 99 / 1, more preferably 95 / 5 to 98 / 2, and even more preferably 96 / 4 to 97 / 3. When the molar ratio ([C1] / [C2]) is within the above range, it is preferable from the viewpoint of the kneading stability of the resulting rubber composition.

[0036] The content of structural units derived from non-conjugated polyene [C1] in the copolymer (S1) is preferably 0.1 to 10.0 mol%, more preferably 0.5 to 8.0 mol%, and even more preferably 1.0 to 7.0 mol%, with the total of structural units derived from ethylene [A1], α-olefin [B1], non-conjugated polyene [C1], and non-conjugated polyene [C2] being 100 mol%.

[0037] The content of structural units derived from non-conjugated polyene [C2] in the copolymer (S1) is preferably 0.1 to 6.0 mol%, more preferably 0.2 to 4.0 mol%, and even more preferably 0.2 to 2.0 mol%, with the total of structural units derived from ethylene [A1], α-olefin [B1], non-conjugated polyene [C1], and non-conjugated polyene [C2] being 100 mol%.

[0038] Furthermore, the total content of structural units derived from non-conjugated polyene [C1] and non-conjugated polyene [C2] is preferably 0.1 to 12.0 mol%, more preferably 0.5 to 10.0 mol%, and even more preferably 1.0 to 9.0 mol%, with the total of structural units derived from ethylene [A1], α-olefin [B1], non-conjugated polyene [C1], and non-conjugated polyene [C2] being 100 mol%. Copolymer (S1) with this content within the above range has sufficient crosslinkability and flexibility. The content of each structural unit in copolymer (S1) is: 13It can be measured by, for example, a 13C-NMR spectrum.

[0039] The copolymer (S1) preferably further satisfies the following requirement (3). 《Requirement (3)》 Requirement (3) satisfies the following formula (I), preferably the following formula (I'). Log{η * (0.01)} / Log{η * (10)} > 0.0753 × {apparent iodine value derived from non-conjugated polyene [C2]} + 1.32 …(I) Log{η * (0.01)} / Log{η * (10)} > 0.0753 × {apparent iodine value derived from non-conjugated polyene [C2]} + 1.33 …(I') (In the formula, η * (0.01) represents the viscosity (Pa·sec) at 0.01 rad / sec at 190°C, and η * (10) represents the viscosity (Pa·sec) at 10 rad / sec at 190°C.)

[0040] The above formula (I) can specifically calculate the apparent iodine value from the following formula (X) by measuring η * (0.01) and η * (10) with a viscoelasticity measuring device and measuring the content ratio (wt%) of the structural unit derived from the above component [C2] by NMR. The molecular weight of iodine is 253.81.

[0041] Apparent iodine value derived from component [C2] = [content ratio (wt%) of the structural unit derived from component [C2]] × Y × 253.81 / (molecular weight of component [C2] as a monomer) ···(X) (In formula (X), Y represents the number of carbon-carbon double bonds contained in the structural unit derived from component [C2].)

[0042] When the copolymer (S1) is within the range defined by formula (I) above, it has more long-chain branches regardless of the low content of component [C2]. In other words, the long-chain branches necessary to obtain excellent roll processability and mold processability can be introduced by copolymerizing a small amount of component [C2], and furthermore, the resulting rubber molded article has excellent compression set due to the low content of residual component [C2].

[0043] On the other hand, if the copolymer (S1) is outside the range defined by formula (I) above, a large amount of component [C2] is required to introduce long-chain branching into the copolymer rubber, which affects excellent roll processability and moldability. As a result, heat resistance and rubber elasticity deteriorate, which significantly negatively impacts product life.

[0044] The Mooney viscosity ML(1+4)100°C of copolymer (S1) is preferably 5 to 150, more preferably 10 to 100, even more preferably 20 to 50, and particularly preferably 25 to 40.

[0045] When the Mooney viscosity ML(1+4)100℃ is within the above range, a copolymer (S1) is obtained that exhibits excellent roll processability even with a high-hardness, oil-free formulation, as well as good post-treatment (ribbon handling properties) and excellent rubber properties. Specifically, the Mooney viscosity ML(1+4)100℃ can be determined by the method described in the examples below.

[0046] This composition may contain two or more copolymers (S1). For example, two or more copolymers (S1) with different (a) ethylene [A1] / α-olefin [B1] molar ratios, (b) iodine values, or (c) intrinsic viscosity [η] can be mixed and used. In particular, for (c), a method of mixing a low intrinsic viscosity component with a high intrinsic viscosity component can be used.

[0047] <Method for producing copolymer (S1)> The copolymer (S1) can be obtained by known manufacturing methods, such as conventional manufacturing methods using a metallocene catalyst. Examples of metallocene catalysts and manufacturing methods using such catalysts include those described in International Publication No. 2009 / 072503 and Japanese Patent Application Publication No. 2017-160388. Commercially available products may also be used.

[0048] <Carbon Black (B)> This composition contains carbon black (B). Carbon black (B) is a component that contributes, for example, to improving the mechanical strength, modulus, and wear resistance of the resulting (crosslinked) molded article.

[0049] Examples of carbon black (B) include SRF, GPF, FEF, MAF, HAF, ISAF, SAF, FT, and MT. The surface of the carbon black may be treated with a silane coupling agent. Examples of commercially available carbon blacks include "Asahi #55G", "Asahi #50HG", "Asahi #60G", "Asahi #60UG", "Asahi #70" (product names, manufactured by Asahi Carbon Co., Ltd.), "Seast V", and "Seast SO" (product names, manufactured by Tokai Carbon Co., Ltd.).

[0050] This composition may contain one type of carbon black (B), or it may contain two or more types of carbon black (B). The carbon black (B) content in this composition is preferably 0.1 to 200 parts by mass, more preferably 10 to 200 parts by mass, even more preferably 20 to 100 parts by mass, and particularly preferably 30 to 50 parts by mass, per 100 parts by mass of copolymer (S1). This configuration is preferable from the viewpoint of the mechanical strength of the resulting (crosslinked) molded article and the processability of the composition.

[0051] <Short fiber (C)> This composition contains short fibers (C). The use of short fibers (C) improves the modulus and mechanical strength of the (crosslinked) molded article formed from this composition. Since the copolymer (S1) also exhibits excellent kneadability with short fibers (C), this composition tends to have excellent moldability.

[0052] Examples of short fibers (C) include fibers made from synthetic resins such as polyamide, polyimide, polyester, polyvinyl alcohol, rayon, polyolefin, polyarylate, polyphenylene sulfide, polyether ether ketone, polyp-phenylene benzobisoxazole, and fluorinated polymers; and natural fibers such as cotton and wood cellulose fibers. Among these, short fibers made from synthetic resins are preferred, and short fibers made from polyamide are more preferred. Short fibers (C) are not usually short fibers formed from copolymers (S1).

[0053] Examples of polyamides include aliphatic polyamides such as polycapramide, poly-ω-aminoheptanoic acid, poly-ω-aminononanoic acid, polyundecaneamide, polyethylenediamine adipamide, polytetramethylene adipamide, polyhexamethylene adipamide, polyhexamethylene sevacamide, polyhexamethylene dodecamide, polyoctamethylene adipamide, and polydecamethylene adipamide; and aromatic polyamides (aramids) such as poly-p-phenylene terephthalamide, polymetaphenylene isophthalamide, coply-p-phenylene-3,4'-oxydiphenylene terephthalamide, polymetaxylylene adipamide, polymetaxylylene pimellamid, polymetaxylylene azeramide, poly-p-xylylene azeramide, and poly-p-xylylene decanamide.

[0054] As for the short fibers (C), from the viewpoint of further improving the tensile stress and tear strength of the resulting (crosslinked) molded article, short fibers made of aromatic polyamide, i.e., aramid short fibers, and more preferably poly(p-phenylene-terephthalamide), poly(metaphenylene-isophthalamide), and poly(p-phenylene-3,4'-oxydiphenylene-terephthalamide) short fibers, are preferred.

[0055] The average fiber length of the short fibers (C) is preferably 0.1 to 50 mm, more preferably 0.5 to 10 mm, even more preferably 0.5 to 6 mm, even more preferably 1.0 to 5.0 mm, and particularly preferably 2.0 to 4.0 mm. The fiber diameter of the short fibers (C) is usually 0.1 to 100 μm, preferably 0.1 to 25 μm, and more preferably 1 to 20 μm.

[0056] The average fiber length of a short fiber (C) can be determined, for example, by taking photographs of the short fibers using an optical microscope, measuring the lengths of 100 randomly selected short fibers in the resulting photographs, and taking the arithmetic mean of these measurements.

[0057] The short fiber (C) may be a chopped fiber (cut fiber) type short fiber or a pulp-like short fiber having fibrils.

[0058] This composition may contain one type of short fiber (C), or it may contain two or more types of short fibers (C). The content of short fibers (C) in this composition is preferably 0.1 to 100 parts by mass, more preferably 0.1 to 30 parts by mass, even more preferably 3 to 20 parts by mass, and particularly preferably 5 to 10 parts by mass, per 100 parts by mass of copolymer (S1). This configuration is preferable from the viewpoint of the modulus and mechanical strength of the resulting (crosslinked) molded article.

[0059] <Other ingredients> This composition may further contain at least one selected from crosslinking agents (D), vulcanization accelerators, vulcanization accelerators, crosslinking aids (E), processing aids (F), surfactants, softeners, inorganic fillers, reinforcing agents, antioxidants, surfactants, hygroscopic agents, antistatic agents, colorants, lubricants, thickeners, and other polymers (excluding copolymers (S1)) (hereinafter also referred to as "other components"). Each of the other components may be used individually or in combination of two or more.

[0060] Crosslinking agent (D) Examples of crosslinking agents (D) include those commonly used when crosslinking rubber, such as organic peroxides, sulfur compounds, phenolic resins, hydrosilicone compounds, amino resins, quinones or their derivatives, amine compounds, azo compounds, epoxy compounds, isocyanate compounds, and quinone dioxime crosslinking agents such as p-quinone dioxime. Among these, organic peroxides and sulfur compounds are preferred.

[0061] If the composition contains a crosslinking agent (D), the amount of crosslinking agent (D) is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the copolymer (S1) and other polymers (such as rubber) that require crosslinking as needed.

[0062] 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)hexine-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.

[0063] When using an organic peroxide as the crosslinking agent (D), it is preferable to use the crosslinking aid (E), which will be described later, in combination. The amount of crosslinking aid (E) added is preferably 0.5 to 10 moles, more preferably 0.6 to 5.0 moles, and even more preferably 0.8 to 3.0 moles per mole of organic peroxide.

[0064] Examples of sulfur-based compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dithiocarbamate. Although sulfur is not a compound, it is conveniently classified as a sulfur-based compound in this specification.

[0065] This composition may contain a vulcanization accelerator. In particular, when a sulfur-based compound is used as the crosslinking agent (D), it is preferable to use a vulcanization accelerator in combination. Examples of vulcanization accelerators include thiazole-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole, 2-(4-morpholinodithio)benzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl-4-morpholinothio)benzothiazole, and dibenzothiadyl disulfide; guanidine-based vulcanization accelerators such as diphenylguanidine, triphenylguanidine, and diorthotrylguanidine; and aldehydeamine-based accelerators such as acetaldehyde-aniline condensates and butyraldehyde-aniline condensates. Examples of vulcanization accelerators include: imidazoline-based vulcanization accelerators such as 2-mercaptoimidazoline; thiourea-based vulcanization accelerators such as diethylthiourea and dibutylthiourea; thiram-based vulcanization accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and dipentamethylenethiuram tetrasulfide; dithioate-based vulcanization accelerators such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, and tellurium diethyldithiocarbamate; thiourea-based vulcanization accelerators such as ethylenethiourea, N,N'-diethylthiourea, and N,N'-dibutylthiourea; and xantate-based vulcanization accelerators such as zinc dibutylxatonate.

[0066] If the composition contains a vulcanization accelerator, the amount of the vulcanization accelerator is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the copolymer (S1) and other polymers (such as rubber) that require crosslinking as needed.

[0067] This composition may contain a vulcanization accelerator. In particular, when a sulfur-based compound is used as the crosslinking agent (D), it is preferable to use a vulcanization accelerator in combination.

[0068] Examples of vulcanization accelerators include zinc oxide, magnesium oxide, and zinc oxide.

[0069] If the composition contains a vulcanization accelerator, the amount of the vulcanization accelerator is preferably 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, and more preferably 3 to 8 parts by mass, based on 100 parts by mass of the copolymer (S1) and other polymers (such as rubber) that require crosslinking as needed.

[0070] Crosslinking agent (E) Crosslinking aid (E) is a compound that acts as a crosslinking reaction catalyst when combined with the crosslinking agent during the crosslinking of this composition by heating.

[0071] Examples of crosslinking aids (E) include acrylic crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyl crosslinking aids such as diallyl phthalate and triallyl isocyanurate; other maleimide crosslinking aids; and divinylbenzene. Among these, acrylic crosslinking aids are preferred, and ethylene glycol dimethacrylate is more preferred.

[0072] If the composition contains a crosslinking aid (E), the amount of crosslinking aid (E) is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, even more preferably 0.8 to 10 parts by mass, and particularly preferably 1.0 to 5.0 parts by mass, per 100 parts by mass of copolymer (S1).

[0073] Processing aid (F) As processing aids (F), a wide range of materials commonly used as processing aids in rubber can be used, such as ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, and esters. Among these, stearic acid is preferred.

[0074] If the composition contains a processing aid (F), the content of the processing aid (F) is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 5.0 parts by mass, even more preferably 0.5 to 3.0 parts by mass, and particularly preferably 0.7 to 2.0 parts by mass, per 100 parts by mass of copolymer (S1).

[0075] Softener Examples of softening agents include petroleum-based softening agents such as process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, and petrolatum; coal tar-based softening agents such as coal tar; fatty oil-based softening agents such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; waxes such as beeswax and carnauba wax; fatty acids or their salts such as ricinoleic acid, palmitic acid, barium stearate, and calcium stearate; naphthenic acid, pine oil, rosin or its derivatives; synthetic polymers such as terpene resins, petroleum resins, and coumarone indene resins; ester-based softening agents such as dioctyl phthalate and dioctyl adipate; and others such as microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricants, tall oil, and sub(factis). Petroleum-based softening agents are preferred, and process oils are more preferred.

[0076] If the composition contains a softening agent, the amount of the softening agent is preferably 2 to 100 parts by mass, more preferably 5 to 100 parts by mass, even more preferably 5 to 30 parts by mass, and particularly preferably 10 to 20 parts by mass, based on 100 parts by mass of the total of the copolymer (S1) and other polymers (elastomers, rubber, etc.) that may be added as needed.

[0077] <Inorganic fillers> Examples of inorganic fillers include light calcium carbonate, heavy calcium carbonate, talc, and clay. Among these, heavy calcium carbonate is preferred.

[0078] If the composition of the present invention contains an inorganic filler, the amount of the inorganic filler is preferably 2 to 50 parts by mass, more preferably 5 to 50 parts by mass, based on 100 parts by mass of the copolymer (S1) and other polymers that may be added as needed.

[0079] Reinforcement agent Examples of reinforcing agents include silica, calcium carbonate, activated calcium carbonate, fine talc, and differential silicic acid. However, the carbon black (B) and inorganic fillers mentioned above are excluded. Among these, silica is preferred.

[0080] If the composition contains a reinforcing agent, the amount of the reinforcing agent is preferably 0.1 to 100 parts by mass, more preferably 5 to 30 parts by mass, even more preferably 6 to 20 parts by mass, and particularly preferably 7 to 15 parts by mass, based on 100 parts by mass of the total of the copolymer (S1) and other polymers (elastomers, rubber, etc.) that may be added as needed.

[0081] Anti-aging agent (stabilizer) This composition, by containing an antioxidant (stabilizer), can extend the lifespan of the (crosslinked) molded articles formed from the composition. Examples of antioxidants include amine-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants.

[0082] Examples of amine-based antioxidants include aromatic secondary amine-based antioxidants such as phenylbutylamine and N,N-di-2-naphthyl-p-phenylenediamine. Examples of phenol-based antioxidants include dibutylhydroxytoluene and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Examples of sulfur-based antioxidants include thioether-based antioxidants such as bis[2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl] sulfide; dithiocarbamate-based antioxidants such as dibutyldithiocarbamate nickel; and 2-mercaptobenzoylimidazole, 2-mercaptobenzoimidazole, zinc salt of 2-mercaptobenzoimidazole, dilaurylthiodipropionate, and distearylthiodipropionate.

[0083] If the composition contains an antioxidant, the amount of the antioxidant is preferably 0.3 to 10 parts by mass, more preferably 1 to 9 parts by mass, even more preferably 3 to 8 parts by mass, and particularly preferably 5 to 7 parts by mass, based on 100 parts by mass of the copolymer (S1) and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0084] Other polymers This composition may further contain other polymers besides the copolymer (S1), such as rubber and / or elastomers. Other polymers that require crosslinking include, for example, ethylene-α-olefin-non-conjugated polyene copolymers other than copolymer (S1), and rubbers such as natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, acrylic rubber, silicone rubber, fluororubber, and urethane rubber.

[0085] Examples of ethylene-α-olefin-non-conjugated polyene copolymers other than copolymer (S1) include ethylene-propylene-ENB copolymer, ethylene-1-butene-ENB copolymer, ethylene-propylene-VNB copolymer, and ethylene-1-butene-VNB copolymer.

[0086] Other polymers that do not require crosslinking include, for example, styrene-butadiene block copolymers (SBS), polystyrene-poly(ethylene-butylene)-polystyrene (SEBS), polystyrene-poly(ethylene-propylene)-polystyrene (SEPS), and other styrene-based thermoplastic elastomers (TPS), such as TPS, olefin-based thermoplastic elastomers (TPO), polyvinyl chloride-based elastomers (TPVC), ester-based thermoplastic elastomers (TPC), amide-based thermoplastic elastomers (TPA), urethane-based thermoplastic elastomers (TPU), and other thermoplastic elastomers (TPZ). If the composition contains other polymers, the content of the other polymers is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, per 100 parts by mass of copolymer (S1).

[0087] <Preparation of this composition> This composition can be prepared by kneading a copolymer (S1), carbon black (B), short fibers (C), and other components at a desired temperature using a kneading machine such as a mixer, kneader, or roll.

[0088] One embodiment of this composition is prepared, for example, as follows: A copolymer (S1), carbon black (B), short fibers (C), and other predetermined components are placed in a kneader and kneaded under predetermined heating conditions (e.g., 80-200°C for 3-30 minutes) to homogenize (A kneading). In A kneading, no crosslinking agent or the like, which would crosslink the copolymer (S1) when heated to the heating temperature of A kneading, is added. After lowering the temperature of the mixture kneaded in A kneading to below the crosslinking temperature of the crosslinking agent (e.g., 130°C or below), the crosslinking agent or the like that was not added in A kneading is added to the mixture, and the mixture is further kneaded under predetermined heating conditions (e.g., roll temperature 30-80°C for 1-30 minutes) to homogenize it (B kneading) to obtain this composition.

[0089] In the composition before the addition of the crosslinking agent (composition A), the Mooney viscosity ML(1+4) at 125°C is preferably 10 to 250, more preferably 10 to 100, even more preferably 20 to 50, and particularly preferably 30 to 45. Compositions with a Mooney viscosity within the above range exhibit good post-processing quality and possess excellent rubber properties.

[0090] [(Cross-linked) molded products, power transmission belts] A (crosslinked) molded article can be obtained from this composition. This composition can be molded by thermoforming methods such as extrusion molding, injection molding, press molding, calendering, transfer molding, and foam molding. The crosslinking temperature of the composition is preferably 140°C or higher, more preferably 150-220°C, and even more preferably 160-200°C. Furthermore, this crosslinking reaction can be carried out in air.

[0091] In the present invention, the above-mentioned (crosslinked) molded article can be suitably used as a component of a power transmission belt. For example, this composition has high adhesive strength suitable for moldability and excellent belt processability. Furthermore, by using this composition, it is possible to manufacture a power transmission belt component with excellent rubber elasticity, abrasion resistance, heat resistance, and cold resistance.

[0092] The power transmission belt of the present invention has a (crosslinked) molded body formed from this composition. Examples of power transmission belts of the present invention include friction transmission belts such as V-belts and V-ribbed belts; interlocking transmission belts such as timing belts; and toothed belts. Examples of power transmission belts include those for automobiles, motorcycles, and general industrial machinery. Examples of V-belts include wrapped belts and raw-edge belts.

[0093] One embodiment of a power transmission belt may have, for example, an adhesive rubber portion in which a core wire is embedded, and further may have a bottom rubber portion formed on the lower surface of the adhesive rubber portion. The power transmission belt may optionally have an upper canvas formed on the adhesive rubber portion and / or a lower canvas formed below the bottom rubber portion. This composition is suitably used, for example, to form the adhesive rubber portion and / or the bottom rubber portion. Specifically, a cross-linked molded portion formed from this composition is suitably used as the adhesive rubber portion and / or the bottom rubber portion.

[0094] The core wire, which is the tensile member of the power transmission belt, extends in the longitudinal direction of the belt within the adhesive rubber portion. Examples of the core wire include polyester cords. The adhesive rubber portion surrounds and adheres to the core wire. In one embodiment, for example, the adhesive rubber portion adhered to the core wire can be formed by arranging the composition around the core wire and crosslinking it. Examples of canvas include cotton, a blend of cotton and polyester, and a blend of cotton and polyamide. [Examples]

[0095] The present invention will be described in more detail below based on examples, but the present invention is not limited in any way to these examples.

[0096] <Physical properties of copolymers> [Composition of copolymer] The molar amounts of each constituent unit of the copolymer are: 1The intensity was determined by measuring it using an H-NMR spectrometer. Details of the measurement conditions are described in International Publication No. 2015 / 122415. The mass fraction (mass%) of each constituent unit of the copolymer is: 13 The copolymer was determined by measurement using 1C-NMR. The measurement was performed using an ECX400P nuclear magnetic resonance spectrometer (JEOL), with a measurement temperature of 120°C, a measurement solvent of orthodichlorobenzene / deuterated benzene = 4 / 1, and 8000 cumulative cycles. 13 The spectrum was obtained by measuring the 1C-NMR spectrum.

[0097] [Iodine value] The apparent iodine value derived from the unconjugated polyene [C2] (hereinafter also referred to as the "[C2] iodine value") was calculated based on the above formula (X).

[0098] [Mooney Viscosity] Mooney viscosity (ML(1+4)100℃) was measured using a Mooney viscometer (SMV202 model, Shimadzu Corporation) in accordance with JIS K6300 (1994).

[0099] [Intrinsic viscosity [η]] The intrinsic viscosity [η] (dl / g) of the copolymer was measured using a fully automatic intrinsic viscometer manufactured by Rigosha Co., Ltd., at a temperature of 135°C and using decalin as the measurement solvent.

[0100] [Weight average molecular weight (Mw)] The weight-average molecular weight (Mw) of the copolymer was determined using a 3D high-temperature GPC instrument (PL-GPC220, manufactured by Polymer Laboratories) under the following measurement conditions. Detector: Differential refractometer / GPC device built-in 2-angle light scattering photometer PD2040 type (manufactured by Precison Detectors) Bridge-type viscometer PL-BV400 (manufactured by Polymer Laboratories) Column: TSKgel GMHHR-H(S)HT x 2 + TSKgel + GMHHR-M(S) x 1 (each with an inner diameter of 7.8mmφ and a length of 300mm) Temperature: 140℃ Mobile phase: 1,2,4-trichlorobenzene (containing 0.025% BHT) Calibration curve preparation method: Use standard polystyrene samples. Injection volume: 0.5mL Sample concentration: Ca 1.0 mg / mL Sample filtration: Filtered using a 1.0 μm pore size sintered filter.

[0101] [Materials used] The following materials were used in the examples and comparative examples described later. [Ethylene-α-olefin-non-conjugated polyene copolymer (S1)] The following copolymer (S1-1) was used as copolymer (S1). Copolymer (S1-1): Trade name "Mitsui EPT8030M", manufactured by Mitsui Chemicals, Inc., ethylene-propylene-ENB-VNB quaternary copolymer obtained using a metallocene catalyst (ethylene / propylene (molar ratio) = 62 / 38, ENB content 20g / 100g, VNB content 0.8g / 100g, melt modulus 9×10 at 190℃ and 100rad / s). 4 MPa, ML(1+4)100℃=32, Log[η * (0.01)] / Log[η * (10)] = 1.41, 0.0753 × D + 1.32 = 1.38 (where D is the apparent iodine value derived from the unconjugated polyene [C2])

[0102] [Other copolymers] In addition to copolymer (S1), the following copolymers (S2-1), (S2-2), and (S3-1) were used. Copolymer (S2-1): Ethylene-propylene-5-vinyl-2-norbornene (VNB) copolymer obtained in Comparative Production Example 1 below. Copolymer (S2-2): Ethylene-propylene-5-vinyl-2-norbornene (VNB) copolymer obtained in Comparative Production Example 2 below. Copolymer (S3-1): Ethylene-1-butene-5-ethylidene-2-norbornene (ENB) copolymer obtained in Comparative Production Example 3 below.

[0103] <Comparative Manufacturing Example 1> The polymerization of ethylene, propylene, and 5-vinyl-2-norbornene (VNB) was carried out continuously at 87°C using a 300 L polymerizer equipped with stirring blades. Hexane (feed rate: 58.3 L / h) was used as the polymerization solvent and was continuously supplied to the polymerizer at a rate of 6.6 kg / h for ethylene, 9.3 kg / h for propylene, 340 g / h for VNB, and 18 NL / h for hydrogen.

[0104] While maintaining a polymerization pressure of 1.6 MPaG and a polymerization temperature of 87°C, di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride was continuously supplied to the polymerizer as the main catalyst at a feed rate of 0.030 mmol / h. In addition, (C6H5)3CB(C6F5)4 was continuously supplied to the polymerizer as a co-catalyst at a feed rate of 0.150 mmol / h, and triisobutylaluminum (TIBA) was continuously supplied as an organoaluminum compound at a feed rate of 4.5 mmol / h.

[0105] In this way, a solution containing 20% ​​by mass of an ethylene-propylene-VNB copolymer formed from ethylene, propylene, and VNB was obtained. A small amount of methanol was added to the polymerization reaction solution withdrawn from the bottom of the polymerizer to stop the polymerization reaction, and the ethylene-propylene-VNB copolymer was separated from the solvent by steam stripping. After that, it was dried under reduced pressure at 80°C overnight.

[0106] Through the above procedure, ethylene-propylene-VNB copolymer (S2-1) was obtained at a rate of 7.8 kg per hour. The physical properties of copolymer (S2-1) were measured by the method described above. The results are shown in Table 1.

[0107] <Comparative Manufacturing Example 2> An ethylene-propylene-VNB copolymer (S2-2) was obtained in accordance with the description of [Production Example 2: Copolymer (S2-1)] in Japanese Patent Publication No. 2024-032012. The physical properties of copolymer (S2-2) were measured by the method described above. The results are shown in Table 1.

[0108] [Table 1]

[0109] <Comparative Manufacturing Example 3> Following the description in [Synthesis Example C1] of International Publication No. 2015 / 122415, an ethylene-1-butene-ENB copolymer (S3-1) having the following properties was obtained. Ethylene-derived structural units: 67.7 mol% Structural units derived from 1-butene: 30.0 mol% Structural units derived from ENB: 2.3 mol% Mooney viscosity ML (1+4) 100℃: 30

[0110] [Other materials] • Processing aid (F): Stearic acid ("Sakura Powdered Stearic Acid" manufactured by NOF Corporation) • Vulcanization accelerator: Two types of zinc oxide (Hakusui Tech Co., Ltd.'s "ZnO#1") • Anti-aging agent 1: Phenolic anti-aging agent (BASF's "Irganox 1010") • Anti-aging agent 2: Imidazole-based anti-aging agent (Sandant MB, manufactured by Sanshin Chemical Industry Co., Ltd.) • Carbon Black (B): Carbon Black (Asahi Carbon Co., Ltd. "Asahi #70") • Silica: Hydrophilic silica ("ULTRASIL VN3" manufactured by EVONIC) • Softener: Paraffin-based process oil (Idemitsu Kosan Co., Ltd.'s "Diana Process Oil PW-380") • Short fibers (C): Aramid short fibers (Toray DuPont's "Kevlar"; poly(p-phenylene terephthalamide); average fiber length 3.5 mm) • Crosslinking agent (D): Dicumyl peroxide (DCP-40C, manufactured by Kayaku Akzo) • Crosslinking agent (E): Ethylene glycol dimethacrylate (San-Ester EG, manufactured by Sanshin Chemical Industry Co., Ltd.)

[0111] [Example 1] Using a MIXTRON BB MIXER (manufactured by Kobe Steel, Ltd., BB-2 type, volume 1.7L, rotor 2WH), 50 parts by mass of copolymer (S1-1), 50 parts by mass of copolymer (S3-1), 1 part by mass of stearic acid as a processing aid (F), 5 parts by mass of ZnO#1 (two types of zinc oxide, JIS K-1410 (2006)) as a vulcanization accelerator, 2 parts by mass of Irganox 1010 as antioxidant 1, 4 parts by mass of Sandant MB as antioxidant 2, 40 parts by mass of Asahi #70 as carbon black (B), 10 parts by mass of ULTRASIL VN3 (silica) as a reinforcing agent, 15 parts by mass of Diana Process Oil PW-380 as a softening agent, and 8 parts by mass of aramid short fibers (C) were mixed and kneaded to obtain formulation 1.

[0112] The mixing conditions for preparing formulation 1 were a rotor speed of 40 rpm and a floating weight pressure of 3 kg / cm². 2 The mixing time was 5 minutes, and the mixing discharge temperature was 144°C. The Mooney viscosity ML(1+4) at 125°C of formulation 1 was measured using a Mooney viscometer (SMV202 model, Shimadzu Corporation) in accordance with JIS K6300 (1994).

[0113] Next, after confirming that the temperature of formulation 1 reached 40°C, formulation 1 was kneaded using a 6-inch roll to add 6.8 parts by mass of DCP-40C as a crosslinking agent (D) and 2 parts by mass of Sunester EG as a crosslinking aid (E) to obtain formulation 2.

[0114] The kneading conditions for preparing formulation 2 were as follows: roll temperature (front roll / rear roll = 50°C / 50°C), roll peripheral speed (front roll / rear roll = 18 rpm / 15 rpm), and roll gap (3 mm). The mixture was kneaded for 8 minutes and then dispensed in small batches to obtain formulation 2.

[0115] Compound 2 was pressed using a press molding machine at 170°C for 15 minutes to produce a 2 mm thick crosslinked sheet. The obtained crosslinked sheet was subjected to hardness tests, tensile tests, and DIN abrasion tests, as described below.

[0116] [Examples 2-4 and Comparative Example 1] The procedure was the same as in Example 1, except that it was based on the composition and vulcanization system described in Table 2.

[0117] <Physical properties of compositions, etc.> [Adhesion (Probe Tack Test)] The probe tack test was performed using a probe tack tester as follows. The above compound 2 was separated into sheets to obtain an uncrosslinked sheet with a thickness of 1 mm. This uncrosslinked sheet was used as a test specimen and fixed to a probe tack tester. Next, the bottom surface of a cylindrical probe (5 mm diameter stainless steel probe) was brought close to one side of the test specimen at a constant speed and brought into contact with it. Then, the cylindrical probe was pressed into the test specimen, and once a certain load was applied to the specimen, it was held for a certain period of time. After that, the cylindrical probe was immediately peeled off the test specimen at a constant speed, and this process was carried out while measuring the test force.

[0118] The above process was carried out under the following conditions. Approach speed: 120mm / min. Pressure: 100g Pressurization time: 20s Peeling speed: 120mm / min. Temperature for placing the probe and test specimen (uncrosslinked sheet): 23°C In the curve representing the relationship between test force and time measured during the above process, the peak value (gf) at which the indentation force is the minimum value was determined (corresponding to the maximum load required to detach the cylindrical probe from the test specimen) when the indentation force is considered positive. Adhesion was evaluated by the magnitude of the absolute value of the peak value.

[0119] [Rolling properties] When preparing composition 2 using the conditions and method described in Example 1, the wrapability and surface condition of the composition were observed when it was wound onto a 6-inch roll (front roll 18 rpm, back roll 15 rpm, roll gap 1 mm) heated to 50°C. The following evaluation criteria were used for evaluation. Evaluation Criteria 4: The rubber is wrapped around the roll, the surface is glossy, and no holes are observed. 3: The roll is wrapped in rubber, and the surface is glossy, but holes are visible. 2: The rubber wraps around the roll, but the surface is not glossy and holes are observed. 1: The rubber does not wrap around the roller, making mixing impossible.

[0120] [Vulcanization rate test] Using an MDR2000P (manufactured by ALPHATECHNOLOGIES) as the measuring device, the torque change obtained under constant temperature and constant shear rate conditions in compound 2 was measured at a temperature of 170°C and for a time of 30 minutes. The difference between the minimum torque S'min and the maximum torque S'max (S'max-S'min), the time it took for the torque of the sample to increase by 1 [dNm] after reaching the minimum torque S'min (TS1), the time it took for the torque of the sample to reach 90% of the value when the minimum torque S'min is set to 0% and the maximum torque S'max is set to 100% (tc90), and the MCR (Maximum Curing Rate, which indicates the maximum slope of the vulcanization curve) [dNm / min] were determined. A smaller tc90 indicates a higher vulcanization rate (crosslinking rate).

[0121] [Hardness Test (Durometer-A)] The flat portions of the above 2mm thick crosslinked sheets are overlapped to form a 12mm thick sheet, JIS The hardness (Duro-A) was measured according to K6253.

[0122] [Tensile test: Modulus, tensile stress at fracture, tensile elongation at fracture] A 2mm thick cross-linked sheet was punched out to create a Type 3 dumbbell test specimen as described in JIS K6251 (1993). Using this specimen, a tensile test was performed according to the method specified in Section 3 of JIS K6251, under the conditions of a measurement temperature of 25°C and a tensile speed of 500 mm / min. The tensile stress (5% modulus (M5)) when the elongation was 5%, the tensile stress (10% modulus (M10)) when the elongation was 10%, the tensile stress (25% modulus (M25)) when the elongation was 25%, the tensile stress (50% modulus (M50)) when the elongation was 50%, the tensile stress (100% modulus (M100)) when the elongation was 100%, the tensile stress at the breaking point (TB), and the tensile elongation at the breaking point (EB) were measured.

[0123] [DIN wear test (DIN wear amount)] A disc-shaped test specimen with a diameter of 16.0 ± 0.2 mm and a thickness of 6 mm or more was prepared from the above cross-linked sheet with a thickness of 2 mm in accordance with JIS-K6264-2:2005. For this test specimen, the amount of wear (DIN wear amount: in mg) was measured using a DIN abrasion tester, with a drum of 150.0 ± 0.2 mm in diameter and 500 mm in length rotated at 40 revolutions / minute, under a load of 1 kgf, and with an abrasion distance of 40.0 ± 0.2 m.

[0124] [Table 2]

Claims

1. An ethylene-α-olefin-non-conjugated polyene copolymer (S1) having a structural unit derived from ethylene [A1], a structural unit derived from an α-olefin [B1] having 3 to 20 carbon atoms, a structural unit derived from a non-conjugated polyene [C1] containing a total of one substructure selected from the group consisting of the following general formulas (I) and (II) in one molecule, and a structural unit derived from a non-conjugated polyene [C2] containing a total of two or more substructures selected from the group consisting of the following general formulas (I) and (II) in one molecule, Carbon black (B) and, A composition for power transmission belts containing short fibers (C). 【Chemistry 1】

2. The transmission belt composition according to claim 1, wherein the copolymer (S1) satisfies the following requirements (1) and (2): (1) The molar ratio [[A1] / [B1]] of structural units derived from ethylene [A1] to structural units derived from α-olefin [B1] is 50 / 50 to 85 / 15; (2) The molar ratio ([C1] / [C2]) of structural units derived from non-conjugated polyene [C1] to structural units derived from non-conjugated polyene [C2] is between 85 / 15 and 99.5 / 0.

5.

3. The transmission belt composition according to claim 1, wherein the copolymer (S1) satisfies the following requirement (3): (3) The following equation (I) is satisfied. Log{η} ＊ (0.01)} / Log{η ＊ (10) > 0.0753 × {apparent iodine value derived from unconjugated polyene [C2]} + 1.32 …(I) (In the formula, η ＊ (0.01) represents the viscosity (Pa·sec) of 0.01 rad / sec at 190°C, and η ＊ (10) represents the viscosity (Pa·sec) at 190°C and 10 rad / sec.

4. The transmission belt composition according to claim 1, wherein the structural unit derived from the α-olefin [B1] includes a structural unit derived from propylene.

5. The transmission belt composition according to claim 1, wherein the structural unit derived from the non-conjugated polyene [C1] includes a structural unit derived from 5-ethylidene-2-norbornene (ENB).

6. The transmission belt composition according to claim 1, comprising a structural unit derived from 5-vinyl-2-norbornene as the structural unit derived from the non-conjugated polyene [C2].

7. The transmission belt composition according to claim 1, wherein the content of the short fibers (C) is 0.1 to 100 parts by mass per 100 parts by mass of the copolymer (S1).

8. The transmission belt composition according to claim 1, wherein the short fiber (C) is an aramid short fiber.

9. The transmission belt composition according to claim 1, wherein the Mooney viscosity ML(1+4) at 100°C of the copolymer (S1) is 5 to 150.

10. The transmission belt composition according to claim 1, further comprising a crosslinking agent (D).

11. The transmission belt composition according to claim 1, further containing 0.1 to 20 parts by mass of a processing aid (F) per 100 parts by mass of the copolymer (S1).

12. The transmission belt composition according to claim 10, further comprising a crosslinking aid (E).

13. A molded article formed from the transmission belt composition according to any one of claims 1 to 12.

14. A transmission belt having the molded body described in claim 13.

15. A crosslinked molded article formed from the transmission belt composition according to any one of claims 1 to 12.

16. A transmission belt having a crosslinked molded body as described in claim 15.

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