Composition for power transmission belts

Abstract

To provide a composition for a transmission belt excellent in tackiness and green strength advantageous for moldability.SOLUTION: A composition for a transmission belt includes: 40 to 90 pts.mass of ethylene-α-olefin-nonconjugated polyene copolymer (A) satisfying a prescribed condition and having a structural unit derived from ethylene [A1], a structural unit derived from α-olefin [A2] having 4 to 20 carbon atoms, and a structural unit derived from nonconjugated polyene [A3]; 0.1 to 200 pts.mass of carbon black (B); 0.1 to 100 pts.mass of staple fibers (C); and 10 to 60 pts.mass of ethylene-α-olefin copolymer (D) having a structural unit derived from ethylene and a structural unit derived from α-olefin having 3 to 20 carbon atoms (where a total of the components (A) and (D) is 100 pts.mass).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a composition for power transmission belts. [Background technology]

[0002] Transmission belts are widely used in automobiles, scooters, and general industrial fields, for example, as friction transmission belts such as wrapped belts, raw-edge belts, V-belts, and V-ribbed belts, as well as as meshing transmission belts such as timing belts.

[0003] Such power transmission belts require adhesiveness, high elasticity, and abrasion resistance. To meet these characteristics, chloroprene rubber is widely used as the rubber material for power transmission belts. However, in recent years, there has been an increasing demand for improved heat and cold resistance, as well as for weight reduction, so the use of ethylene-propylene-non-conjugated polyene copolymer (EPT) rubber as a substitute for chloroprene rubber is being considered (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

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

[0005] Patent documents 1 and 2 describe the compounding of short fibers into EPT rubber, but EPT rubber has poor compatibility with short fibers, which tends to make belt molding difficult due to poor kneadability and insufficient adhesiveness. Furthermore, there is a need for further improvement in green strength (strength before crosslinking), which is required during the molding process.

[0006] The object of the present invention is to provide a transmission belt composition that is advantageous for moldability and has excellent adhesiveness and green strength. [Means for solving the problem]

[0007] The inventors diligently conducted research to solve the above problems. As a result, they discovered that the above problems could be solved by blending a specific amount of ethylene-α-olefin-nonconjugated polyene copolymer, carbon black, short fibers, and the ethylene-α-olefin copolymer, and thus completed the present invention.

[0008] A transmission belt composition according to one embodiment of the present invention contains, for example, 40 to 90 parts by mass of an ethylene-α-olefin-non-conjugated polyene copolymer (A) having structural units derived from ethylene [A1], structural units derived from α-olefin having 4 to 20 carbon atoms [A2], and structural units derived from non-conjugated polyene [A3], and satisfying the following requirements (1) to (3); 0.1 to 200 parts by mass of carbon black (B); 0.1 to 100 parts by mass of short fibers (C); and 10 to 60 parts by mass of an ethylene-α-olefin copolymer (D) having structural units derived from ethylene and structural units derived from α-olefin having 3 to 20 carbon atoms (provided that the total of components (A) and (D) is 100 parts by mass). (1) The molar ratio [[A1] / [A2]] of structural units derived from ethylene [A1] to structural units derived from α-olefins [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10. (2) The content of structural units derived from non-conjugated polyene [A3] is 0.1 to 6.0 mol%, with the total of structural units derived from [A1], [A2], and [A3] being 100 mol%. (3) The B value expressed by the following formula (i) is 1.20 or greater. B value=([EX]+2[Y]) / [2×[E]×([X]+[Y])]···(i) [Here, [E], [X], and [Y] respectively represent the molar fractions of structural units derived from ethylene [A1], α-olefins [A2] having 4 to 20 carbon atoms, and non-conjugated polyenes [A3], and [EX] represents the ethylene [A1]-α-olefin [A2] having 4 to 20 carbon atoms diad chain fraction.]

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a composition for a transmission belt that has adhesiveness advantageous for molding processability and excellent green strength.

Modes for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail. [Composition for Transmission Belt] The composition for a transmission belt of the present invention (hereinafter also referred to as "the composition of the present invention") contains an ethylene·α-olefin·non-conjugated polyene copolymer (A) described below, carbon black (B), short fibers (C), and an ethylene·α-olefin copolymer (D).

[0011] <Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer (A)> The ethylene·α-olefin·non-conjugated polyene copolymer (A) has a structural unit derived from ethylene [A1], a structural unit derived from an α-olefin [A2] having 4 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene [A3], and satisfies the following requirements (1) to (3). Hereinafter, the said (A) is also referred to as "component (A)". Component (A) preferably satisfies requirement (4) or (4') described later in one embodiment.

[0012] Note that component (A) can have a structural unit derived from ethylene [A1], a structural unit derived from at least one kind of α-olefin [A2] having 4 to 20 carbon atoms, and a structural unit derived from at least one kind of non-conjugated polyene [A3].

[0013] (1) The molar ratio [[A1] / [A2]] of structural units derived from ethylene [A1] to structural units derived from α-olefins [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10. (2) The content of structural units derived from non-conjugated polyene [A3] is 0.1 to 6.0 mol%, with the total of structural units derived from [A1], [A2], and [A3] being 100 mol%. (3) The B value, expressed by the following formula (i), is 1.20 or greater. B value=([EX]+2[Y]) / [2×[E]×([X]+[Y])]···(i) Here, [E], [X], and [Y] represent the mole fractions of structural units derived from ethylene [A1], α-olefins with 4 to 20 carbon atoms [A2], and non-conjugated polyenes [A3], respectively, and [EX] represents the ethylene [A1]-α-olefins with 4 to 20 carbon atoms [A2] dyad chain fraction.

[0014] Examples of α-olefins having 4 to 20 carbon atoms [A2] include linear α-olefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-nonadecene, and 1-eicosene; and side-chain-containing α-olefins such as 4-methyl-1-pentene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. Among these, α-olefins having 4 to 10 carbon atoms are preferred, 1-butene, 1-hexene, and 1-octene are more preferred, and 1-butene is even more preferred.

[0015] α-olefins [A2] having 4 to 20 carbon atoms can be used alone or in combination of two or more types. Ethylene-propylene-non-conjugated polyene copolymers in which α-olefin is propylene tend to have low adhesive strength between the resulting compositions, and therefore tend to have poor moldability into molded articles and crosslinked molded articles (hereinafter collectively referred to as "(crosslinked) molded articles"). Furthermore, these copolymers tend to have poor kneadability with short fibers (C).

[0016] On the other hand, in the present invention, at least component (A) is used as the rubber component. Since component (A) has structural units derived from α-olefin [A2] having 4 to 20 carbon atoms, it is presumed that the adhesive strength between the resulting compositions is increased, and therefore the composition has high moldability as a (crosslinked) molded article, especially as a power transmission belt. Furthermore, component (A) also has excellent kneadability with short fibers (C).

[0017] Examples of non-conjugated polyenes [A3] include linear non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, and 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, and 5-isopropylidene-2-norbornene. Examples of trienes include cyclic non-conjugated dienes such as rubornene and 6-chloromethyl-5-isopropenyl-2-norbornene; and trienes such as 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,5-norbornadiene, 1,3,7-octatriene, 1,4,9-decatriene, 4,8-dimethyl-1,4,8-decatriene, and 4-ethylidene-8-methyl-1,7-nonadiene. Among these, linear non-conjugated dienes such as 1,4-hexadiene and cyclic non-conjugated dienes such as 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene are preferred, cyclic non-conjugated dienes are more preferred, and 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene are even more preferred.

[0018] Non-conjugated polyenes [A3] can be used alone or in combination of two or more types. Component (A) may include, for example, ethylene·1-butene·1,4-hexadiene copolymer, ethylene·1-pentene·1,4-hexadiene copolymer, ethylene·1-hexene·1,4-hexadiene copolymer, ethylene·1-heptene·1,4-hexadiene copolymer, ethylene·1-octene·1,4-hexadiene copolymer, ethylene·1-nonene·1,4-hexadiene copolymer, ethylene·1-decene·1,4-hexadiene copolymer, and ethylene·1-butene·1-octene·1,4-hexadiene copolymer. Xadiene copolymer, ethylene·1-butene·5-ethylidene-2-norbornene copolymer, ethylene·1-pentene·5-ethylidene-2-norbornene copolymer, ethylene·1-hexene·5-ethylidene-2-norbornene copolymer, ethylene·1-heptene·5-ethylidene-2-norbornene copolymer, ethylene·1-octene·5-ethylidene-2-norbornene copolymer, ethylene·1-nonene·5-ethylidene-2-norbornene copolymer, ethylene·1-decene·5-ethylidene ¹-2-norbornene copolymer, ethylene·1-butene·1-octene·5-ethylidene-2-norbornene copolymer, ethylene·1-butene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, ethylene·1-pentene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, ethylene·1-hexene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, ethylene·1-heptene·5-ethylidene-2-norbornene copolymer Examples include ethylene·5-vinyl-2-norbornene copolymer, ethylene·1-octene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, ethylene·1-nonene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, ethylene·1-decene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer, and ethylene·1-butene·1-octene·5-ethylidene-2-norbornene·5-vinyl-2-norbornene copolymer.

[0019] 《Requirement (1)》 Component (A) has a molar ratio [[A1] / [A2]] of structural units derived from (1) ethylene [A1] and structural units derived from α-olefins [A2] with 4 to 20 carbon atoms, ranging from 40 / 60 to 90 / 10. Component (A) with a molar ratio within the above range exhibits an excellent balance between rubber elasticity at low temperatures and tensile strength at room temperature.

[0020] The lower limit of [A1] / [A2] is preferably 45 / 55, more preferably 50 / 50, and particularly preferably 55 / 45. The upper limit of [A1] / [A2] is preferably 80 / 20, more preferably 75 / 25, and even more preferably 70 / 30.

[0021] 《Requirement (2)》 Component (A) has a content of structural units derived from (2) non-conjugated polyene [A3] of 0.1 to 6.0 mol%, where the total of structural units derived from [A1], [A2], and [A3] is 100 mol%. Component (A) with this content within the above range has sufficient crosslinkability and flexibility.

[0022] The lower limit of the content of structural units derived from [A3] is preferably 0.5 mol%. The upper limit of the content of structural units derived from [A3] is preferably 4.0 mol%, more preferably 3.5 mol%, and even more preferably 3.0 mol%.

[0023] 《Requirement (3)》 Component (A) has a B value represented by (3) formula (i) above that is 1.20 or more, preferably 1.20 to 1.80, and more preferably 1.22 to 1.40.

[0024] Ethylene-α-olefin-non-conjugated polyene copolymers with a B value of less than 1.20 may exhibit high compression set at low temperatures, potentially resulting in an unfavorable balance between rubber elasticity at low temperatures and tensile strength at room temperature. Component (A) with a B value of 1.20 or higher exhibits high alternation of monomer units constituting the copolymer and low crystallinity, thus improving the processability of the resulting composition.

[0025] The B value is an indicator of the randomness of the copolymer monomer chain distribution in the copolymer, and in formula (i) above, [E], [X], [Y], and [EX] are 13 The 1C-NMR spectrum can be measured and determined based on the reports of JC Randall [Macromolecules, 15, 353 (1982)] and J. Ray [Macromolecules, 10, 773 (1977)]. On the other hand, the molar amounts of structural units derived from ethylene [A1], structural units derived from α-olefins with 4 to 20 carbon atoms [A2], and structural units derived from unconjugated polyenes [A3] in (1) to (2) above are: 1 This can be determined by intensity measurement using an H-NMR spectrometer.

[0026] 《Requirement (4)》 Component (A) is (4) Mooney viscosity ML at 100°C. (1+4) The temperature at 100°C is preferably 5 to 150, more preferably 5 to 100, and even more preferably 5 to 50. Component (A) with a Mooney viscosity within the above range exhibits good processability and fluidity, as well as good post-processing quality (ribbon handling properties) and excellent rubber properties.

[0027] 《Requirement (4')》 Component (A) is (4') Mooney viscosity ML at 125°C. (1+4) At 125°C, the viscosity is preferably 3 to 100, more preferably 3 to 70, and even more preferably 3 to 30. Component (A) with a Mooney viscosity within the above range exhibits good processability and fluidity, as well as good post-processing quality (ribbon handling properties) and excellent rubber properties.

[0028] The composition of the present invention may contain one component (A) or two or more components (A). The content of component (A) in the composition of the present invention is 40 to 90 parts by mass, preferably 42 to 88 parts by mass, and more preferably 45 to 85 parts by mass, based on 100 parts by mass of the total of component (A) and component (D) described later. This configuration is preferable from the viewpoint of the processability of the composition of the present invention.

[0029] Furthermore, the content of component (A) in the composition of the present invention is usually 10% by mass or more, preferably 20 to 80% by mass.

[0030] 《Manufacturing Method of Component (A)》 Component (A) can be obtained by conventionally known manufacturing methods using a metallocene catalyst. Examples of metallocene catalysts and manufacturing methods using such catalysts can be found in, for example, International Publication No. 2015 / 122415, particularly in paragraphs

[0249] to

[0320] of said publication.

[0031] in particular, A transition metal compound (a) represented by the following formula (a), Component (A) can be obtained by copolymerizing ethylene [A1], a carbon-4 to carbon-20 α-olefin [A2], and a non-conjugated polyene [A3] in the presence of an olefin polymerization catalyst comprising at least one compound (b) selected from an organometallic compound (b-1), an organoaluminum oxy compound (b-2), and a compound (b-3) that reacts with a transition metal compound (a) to form an ion pair.

[0032] [ka]

[0033] Let's explain the above formula (a). M is a titanium atom, a zirconium atom, or a hafnium atom. R is a substituted aryl group obtained by independently substituting one or more hydrogen atoms of an aryl group with an electron-donating group whose Hammett substitution constant σ is -0.2 or less. If the substituted aryl group has multiple electron-donating groups, each electron-donating group may be the same or different.

[0034] Q is selected from halogen atoms, hydrocarbon groups having 1 to 20 carbon atoms, anionic ligands, and neutral ligands that can coordinate with lone pairs of electrons, in the same or different combinations, and is preferably a halogen atom.

[0035] j is an integer between 1 and 4, preferably 2. Examples of aryl groups in R include phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, phenantrenyl, tetraceryl, chrysenyl, pyrenyl, indenyl, azurenyl, pyrrolyl, pyridyl, furanyl, and thiophenyl groups, with phenyl being preferred.

[0036] Electron-donating groups with a Hammett substitution constant σ of -0.2 or less are defined and exemplified as follows. Hammett's rule is an empirical rule proposed by L.P. Hammett in 1935 to quantitatively discuss the effects of substituents on the reaction or equilibrium of benzene derivatives, and it is widely accepted today. The substituent constants obtained by Hammett's rule include σp when substituted at the para position of the benzene ring and σm when substituted at the meta position; these values ​​can be found in many common literatures. For example, the literature by Hansch and Taft [Chem. Rev., 91, 165 (1991)] provides detailed descriptions of a very wide range of substituents. However, the values ​​of σp and σm listed in these literatures may differ slightly from one literature to another, even for the same substituent. In this specification, to avoid confusion arising from such situations, the values ​​listed in Table 1 (pp. 168-175) of the literature by Hansch and Taft [Chem. Rev., 91, 165 (1991)] are defined as the Hammett substitution constants σp and σm for substituents as far as is described herein. In this specification, an electron-donating group with a Hammett substitution constant σ of -0.2 or less is defined as an electron-donating group with σp of -0.2 or less when the electron-donating group is substituted at the para position (position 4) of the phenyl group, and an electron-donating group with σm of -0.2 or less when the electron-donating group is substituted at the meta position (position 3) of the phenyl group. Furthermore, if the electron-donating group is substituted at the ortho position (position 2) of the phenyl group, or at any position of an aryl group other than a phenyl group, it is an electron-donating group with σp of -0.2 or less.

[0037] Examples of electron-donating groups with a Hammett substitution constant σp or σm of -0.2 or less include nitrogen-containing groups such as p-amino group (4-amino group), p-dimethylamino group (4-dimethylamino group), p-diethylamino group (4-diethylamino group), and m-diethylamino group (3-diethylamino group); oxygen-containing groups such as p-methoxy group (4-methoxy group) and p-ethoxy group (4-ethoxy group); tertiary hydrocarbon groups such as pt-butyl group (4-t-butyl group); and silicon-containing groups such as p-trimethylsiloxy group (4-trimethylsiloxy group).

[0038] Preferably, R is a substituted phenyl group containing a group independently selected from the nitrogen-containing group and the oxygen-containing group as electron-donating groups. The substituted aryl group may have other substituents selected from hydrocarbon groups having 1 to 20 carbon atoms, silicon-containing groups, nitrogen-containing groups, oxygen-containing groups, halogen atoms, and halogen-containing groups, other than electron-donating groups with a Hammett substituent constant σ of -0.2 or less. If the substituted aryl group has multiple other substituents, each of these other substituents may be the same or different.

[0039] It is preferable that the sum of the Hammett substitution constants σ of electron-donating groups with a Hammett substitution constant σ of -0.2 or less in one substituted aryl group and the individual Hammett substitution constants σ of other substituents is -0.15 or less. Examples of such substituted aryl groups include m,p-dimethoxyphenyl group (3,4-dimethoxyphenyl group), p-(dimethylamino)-m-methoxyphenyl group (4-(dimethylamino)-3-methoxyphenyl group), p-(dimethylamino)-m-methylphenyl group (4-(dimethylamino)-3-methylphenyl group), p-methoxy-m-methylphenyl group (4-methoxy-3-methylphenyl group), and p-methoxy-m,m-dimethylphenyl group (4-methoxy-3,5-dimethylphenyl group).

[0040] Examples of halogen atoms in Q include fluorine, chlorine, bromine, and iodine; examples of hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups having 1 to 10 carbon atoms and cycloalkyl groups having 3 to 10 carbon atoms; examples of anionic ligands include alkoxy groups, allyloxy groups, carboxylate groups, and sulfonate groups; examples of neutral ligands that can coordinate with a lone pair of electrons include organophosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, and diphenylmethylphosphine, and ether compounds such as tetrahydrofuran, diethyl ether, dioxane, and 1,2-dimethoxyethane.

[0041] Examples of transition metal compounds (a) include [bis(4-methoxyphenyl)methylene(η) 5 -cyclopentadienyl)(η 5 Hafnium dichloride (-2,3,6,7-tetramethylfluorenyl) is an example.

[0042] Examples of organometallic compounds (b-1) (excluding organoaluminum oxy compounds (b-2)) include trialkylaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-n-octylaluminum, as well as organoaluminum compounds such as tricycloalkylaluminum, isobutylaluminum dichloride, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminum sesquichloride, methylaluminum dichloride, dimethylaluminum chloride, and diisobutylaluminum hydride.

[0043] Examples of organoaluminum oxy compounds (b-2) include conventionally known aluminoxanes. Examples of compounds (b-3) that react with transition metal compounds (a) to form ion pairs include Lewis acids, ionic compounds, borane compounds, and carborane compounds described in Japanese Patent Publication No. 1-501950, Japanese Patent Publication No. 1-502036, Japanese Patent Publication No. 3-179005, Japanese Patent Publication No. 3-179006, Japanese Patent Publication No. 3-207703, Japanese Patent Publication No. 3-207704, USP-5321106, and International Publication No. 2015 / 122415.

[0044] The catalyst for olefin polymerization may optionally include a support (c). The support (c) is an inorganic or organic compound, in the form of a granular or particulate solid. Among these, porous oxides, inorganic halides, clays, clay minerals, or ion-exchangeable layered compounds are preferred as inorganic compounds.

[0045] Polymerization can be carried out using either liquid-phase polymerization methods such as solution polymerization or suspension polymerization, or gas-phase polymerization methods. The polymerization temperature is usually -50 to +200°C, preferably 0 to 200°C. The polymerization pressure is usually atmospheric pressure to 10 MPa gauge pressure, preferably atmospheric pressure to 5 MPa gauge pressure. The polymerization reaction can be carried out using batch, semi-continuous, or continuous methods. Furthermore, polymerization can be carried out in two or more stages with different reaction conditions.

[0046] <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.

[0047] 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.).

[0048] The composition of the present invention 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 the composition of the present invention is 0.1 to 300 parts by mass, preferably 10 to 250 parts by mass, and more preferably 20 to 200 parts by mass, based on 100 parts by mass of the total of components (A) and (D). This configuration is preferable from the viewpoint of the mechanical strength of the resulting (crosslinked) molded article and the processability of the composition of the present invention.

[0049] <Short Fiber (C)> The composition of the present invention contains short fibers (C). By using short fibers (C), the modulus and mechanical strength of the (crosslinked) molded article formed from the composition can be improved. Since component (A) also has excellent kneadability with short fibers (C), the composition of the present invention tends to have excellent moldability.

[0050] 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 usually not short fibers formed from component (A).

[0051] 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; polyparaffin Examples of aromatic polyamides (aramids) include phenylene terephthalamide (trade name "Kevlar," manufactured by Toray DuPont), polymetaphenylene isophthalamide, coply-paraphenylene-3,4'-oxydiphenylene terephthalamide, polymetaxylylene adipamide, polymetaxylylene pimellamid, polymetaxylylene azeramide, polyparaxylylene azeramide, and polyparaxylylene decanamide.

[0052] As for the short fibers (C), short fibers made of aliphatic polyamide, i.e., nylon short fibers, are preferred from the viewpoint of improving the tensile stress and tear strength of the resulting (crosslinked) molded article and cost, and nylon 6 and nylon 66 are more preferred.

[0053] The average fiber length of the short fibers (C) is typically 0.1 to 50 mm, preferably 0.5 to 10 mm, and more preferably 0.5 to 6 mm. The fiber diameter of the short fibers (C) is typically 0.1 to 100 μm, preferably 0.1 to 25 μm, and more preferably 1 to 20 μm.

[0054] 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.

[0055] The short fiber (C) may be a chopped fiber (cut fiber) type short fiber or a pulp-type short fiber having fibrils.

[0056] The composition of the present invention 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 the composition of the present invention is usually 0.1 to 100 parts by mass, preferably 0.1 to 50 parts by mass, and more preferably 3 to 30 parts by mass, based on 100 parts by mass of the total of components (A) and (D). This embodiment is preferable from the viewpoint of modulus and mechanical strength of the resulting (crosslinked) molded article.

[0057] <Ethylene·α-Olefin Copolymer (D)> The composition of the present invention contains an ethylene-α-olefin copolymer (D) (hereinafter also referred to as "component (D)") having structural units derived from ethylene and structural units derived from α-olefins having 3 to 20 carbon atoms.

[0058] As for the α-olefin, an α-olefin having 3 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, is desirable, as it provides a transmission belt with excellent mechanical strength. Specific examples of such α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, and the like. Among them, propylene, 1-butene, 1-hexene, 1-octene, etc. are preferably used, and 1-butene is particularly preferred. These α-olefins may be used alone or in combination of two or more.

[0059] In component (D), the content of the structural unit derived from ethylene is preferably 50 to 85 mol%, more preferably 50 to 80 mol% (however, the total of the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to carbon atoms is 100 mol%). When the content of the structural unit derived from ethylene is within the above range, a composition excellent in compatibility with component (A) can be obtained.

[0060] Component (D) preferably satisfies at least one of the following requirements (i) to (iv). (i) Melting point The melting point of component (D) is preferably 110°C or lower, more preferably 0 to 105°C, and even more preferably 0 to 100°C. When the melting point of component (D) is within the above range, unmolten component (D) does not remain even at a low kneading temperature, and in particular, a transmission belt having a small molding shrinkage rate and excellent abrasion resistance can be obtained. The melting point of component (D) can be measured by the method described in JIS K 7121.

[0061] (ii) Density The density of component (D) is preferably 840 to 920 kg / m 3 and more preferably 850 to 915 kg / m 3 and even more preferably 855 to 910 kg / m 3Therefore, when the density is within the above range, a transmission belt with low molding shrinkage, excellent strength characteristics, and wear resistance can be obtained. The density of component (D) can be measured by the method described in ASTM D1505.

[0062] (iii) MFR The MFR of component (D) at 190°C and 2.16 kg is preferably 0.1 to 50 g / 10 min, more preferably 0.2 to 30.0 g / 10 min, and even more preferably 0.3 to 10 g / 10 min. When the MFR is within this range, a composition with low molding shrinkage and excellent processability can be obtained. The MFR of component (D) can be measured by the method described in ASTM D1238.

[0063] (iv) Mw / Mn The ratio Mw / Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn, determined by gel permeation chromatography (GPC) of component (D), is preferably in the range of 1.5 to 10.0.

[0064] The weight-average molecular weight (Mw) of component (D), determined by GPC, is preferably in the range of 10,000 to 500,000, more preferably 20,000 to 300,000, and even more preferably in the range of 20,000 to 200,000.

[0065] The number-average molecular weight (Mn) of component (D) determined by GPC is preferably in the range of 1,000 to 250,000, more preferably 2,000 to 150,000, and even more preferably in the range of 2,000 to 100,000.

[0066] When the weight-average molecular weight of component (D) is within the aforementioned range, a transmission belt with low molding shrinkage and excellent wear resistance can be obtained. Furthermore, the low amount of low molecular weight components is preferable because it reduces the likelihood of volatilization or leaching of these low molecular weight components in the resulting transmission belt.

[0067] Component (D) is preferably solid at temperatures ranging from room temperature to approximately 100°C, and more preferably at around 90°C.

[0068] Component (D) can be produced by copolymerizing ethylene and α-olefin using conventionally known methods, for example, with a vanadium-based catalyst, a Ziegler-Natta catalyst, or a metallocene catalyst. A method using a metallocene catalyst is preferred because it allows for easy acquisition of copolymers that satisfy the aforementioned physical properties. More specifically, a method using a catalyst containing a metallocene compound and an aluminum-containing compound as described in International Publication No. 2008 / 152935, or a catalyst consisting of a metallocene compound and an organoaluminum oxy compound or an ionized ionic compound as described in Japanese Patent Publication No. 9-40586, is preferred.

[0069] The composition of the present invention may contain one component (D) or two or more components (D). The content of component (D) in the composition of the present invention is 10 to 60 parts by mass, preferably 12 to 48 parts by mass, and more preferably 15 to 55 parts by mass, based on 100 parts by mass of the total of components (A) and (D). This embodiment is preferred because the resulting composition has excellent tackiness and green strength, which are advantageous for moldability.

[0070] <Other Components> The composition of the present invention preferably further contains a crosslinking agent. The composition of the present invention may further contain at least one selected from crosslinking aids, softeners, inorganic fillers, reinforcing agents, antioxidants, processing aids, activators, hygroscopic agents, antistatic agents, colorants, metal salts of α,β-unsaturated organic acids, lubricants, and thickeners. The composition of the present invention may further contain other polymers other than components (A) and (D), such as elastomers and / or rubbers. Each of the components described below may be used alone or in combination of two or more.

[0071] 《Crosslinking Agent》 Examples of crosslinking agents 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, and isocyanate compounds. Among these, organic peroxides and sulfur compounds are preferred.

[0072] Examples of organic peroxides include dicumyl peroxide, 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, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

[0073] In the composition of the present invention, when an organic peroxide is used as a crosslinking agent, the content of the organic peroxide is usually 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, based on 100 parts by mass of the total of component (A), component (D), and other polymers (such as rubber) that require crosslinking as needed.

[0074] When using an organic peroxide as a crosslinking agent, it is preferable to use a crosslinking aid in combination. In this case, the composition of the present invention further containing a crosslinking aid may be used, and the organic peroxide may be added to the composition before the crosslinking process, and then the crosslinking process may be carried out.

[0075] Examples of crosslinking aids include sulfur; quinone dioxime crosslinking aids such as p-quinone dioxime; crosslinking aids having two or more ethylenically double bonds; maleimide crosslinking aids; and metal oxides such as zinc oxide (e.g., ZnO#1, zinc oxide type 2 (JIS standard (K-1410)), manufactured by Hakusui Tech Co., Ltd.), magnesium oxide, and zinc oxide (e.g., zinc oxide such as "META-Z102" (product name; manufactured by Inoue Lime Industry Co., Ltd.)). Crosslinking aids having two or more ethylenically double bonds are preferred.

[0076] The number of ethylenically active double bonds in a crosslinking aid having two or more ethylenically active double bonds is preferably 2 to 6, more preferably 2 to 4. It is believed that by using the crosslinking aid, a good network can be formed between, for example, a copolymer (A) and short fibers (C). Examples of crosslinking aids having two or more ethylenically active double bonds include (meth)acrylic crosslinking aids such as ethylene glycol di(meth)acrylate and trimethylolpropane tri(meth)acrylate; allyl crosslinking aids such as diallyl phthalate and triallyl isocyanurate; and vinyl crosslinking aids such as divinylbenzene. Among these, (meth)acrylic crosslinking aids are preferred, and ethylene glycol dimethacrylate is more preferred.

[0077] When the composition of the present invention contains a crosslinking aid, the amount of the crosslinking aid is usually 0.5 to 10 moles, preferably 0.5 to 7 moles, and more preferably 1 to 5 moles, per mole of organic peroxide.

[0078] When sulfur-based compounds are used as crosslinking agents, specific examples include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dithiocarbamate.

[0079] In the composition of the present invention, when a sulfur-based compound is used as a crosslinking agent, the content of the sulfur-based compound is usually 0.3 to 10 parts by mass, preferably 0.5 to 7.0 parts by mass, and more preferably 0.7 to 5.0 parts by mass, based on 100 parts by mass of the total of component (A), component (D), and other polymers (such as rubber) that require crosslinking as needed.

[0080] When using sulfur compounds as crosslinking agents, it is preferable to use vulcanization accelerators 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; aldehydeamine-based vulcanization accelerators such as acetaldehyde-aniline condensate and butyraldehyde-aniline condensate; and 2-mercaptoimidazoli Examples of other vulcanization accelerators include: imidazoline-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 (e.g., Suncellar 22C (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), N,N'-diethylthiourea, and N,N'-dibutylthiourea); xantate-based vulcanization accelerators such as zinc dibutylxatonate; and zinc oxide.

[0081] When the composition of the present invention contains a vulcanization accelerator, the amount of the vulcanization accelerator is usually 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, based on 100 parts by mass of the total of component (A), component (D), and other polymers (such as rubber) that require crosslinking as needed.

[0082] A vulcanization aid can be preferably used when the crosslinking agent is a sulfur-based compound. Examples include zinc oxide (e.g., ZnO#1, two types of zinc oxide, manufactured by Hakusui Tech Co., Ltd.), magnesium oxide, and zinc oxide (e.g., zinc oxide such as "META-Z102" (product name; manufactured by Inoue Lime Industry Co., Ltd.)).

[0083] When the composition of the present invention contains a vulcanization aid, the amount of the vulcanization aid is usually 1 to 20 parts by mass per 100 parts by mass of the total of component (A), component (D), and other polymers (such as rubber) that require crosslinking as needed.

[0084] 《Softening Agent》 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, stearic 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.

[0085] If the composition of the present invention contains a softening agent, the amount of the softening agent is usually 2 to 100 parts by mass, preferably 5 to 100 parts by mass, based on 100 parts by mass of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0086] 《Inorganic Filler》 Examples of inorganic fillers include light calcium carbonate, heavy calcium carbonate, talc, and clay. Among these, heavy calcium carbonate is preferred.

[0087] When the composition of the present invention 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, based on 100 parts by mass of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0088] 《Reinforcing Agent》 Examples of reinforcing agents include silica, calcium carbonate, activated calcium carbonate, fine talc powder, and differential silicic acid, excluding the aforementioned carbon black (B).

[0089] If the composition of the present invention contains a reinforcing agent, the amount of the reinforcing agent is usually 0.1 to 100 parts by mass, preferably 5 to 30 parts by mass, based on 100 parts by mass of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0090] 《Antioxidant (Stabilizer)》 The composition of the present invention, by containing an antioxidant (stabilizer), can extend the lifespan of the (crosslinked) molded article formed from the composition. Examples of antioxidants include amine-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants.

[0091] 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.

[0092] When the composition of the present invention contains an anti-aging agent, the amount of the anti-aging agent is usually 0.3 to 10 parts by mass, preferably 0.5 to 7.0 parts by mass, based on 100 parts by mass of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0093] 《Processing Aid》 As processing aids, those commonly used in rubber processing can be widely used. Examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, and esters. Among these, stearic acid is preferred.

[0094] When the composition of the present invention contains a processing aid, the amount of the processing aid is usually 10 parts by mass or less, preferably 8.0 parts by mass or less, based on 100 parts by mass of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0095] 《Activator》 Examples of activators include amines such as di-n-butylamine, dicyclohexylamine, and monoelanolamine; activators such as diethylene glycol, polyethylene glycol, lecithin, triaryl merilate, and zinc compounds of aliphatic or aromatic carboxylic acids; zinc peroxide moduloides; kutadecyltrimethylammonium bromide, synthetic hydrotalcite, and special quaternary ammonium compounds.

[0096] If the composition of the present invention contains an activator, 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 total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0097] 《Humectant》 Examples of desiccants include calcium oxide, silica gel, sodium sulfate, molecular sieves, zeolite, and white carbon. If the composition of the present invention contains a desiccant, the amount of the desiccant 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 total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that are optionally blended.

[0098] 《Metal Salt of α,β-Unsaturated Organic Acid》 When the composition of the present invention contains a metal salt of an α,β-unsaturated organic acid, it is possible to improve the dynamic fatigue resistance and wear resistance of the composition in a well-balanced manner.

[0099] Examples of metal salts of α,β-unsaturated organic acids include metal salts of acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, ethacrylic acid, vinylacrylic acid, itaconic acid, methylitaconic acid, aconitic acid, methylaconitic acid, crotonic acid, alpha-methylcrotonic acid, cinnamic acid, and 2,4-dihydroxycinnamic acid. These salts can be zinc, cadmium, calcium, magnesium, sodium, or aluminum salts, but zinc salts are particularly preferred. Preferred metal salts of α,β-unsaturated organic acids are zinc diacrylate and zinc dimethacrylate, with zinc dimethacrylate being particularly preferred. Metal salts of α,β-unsaturated organic acids can be used alone or in combination of two or more.

[0100] The metal salt of the α,β-unsaturated organic acid is used in an amount of preferably 0.5 to 30 parts by weight, more preferably 1 to 25 parts by weight, and particularly preferably 2 to 20 parts by weight, based on 100 parts by weight of the total of component (A), component (D), and other polymers (elastomers, rubber, etc.) that may be blended as needed.

[0101] 《Other Polymers》 The composition of the present invention may further contain other polymers other than components (A) and (D). Other polymers that require crosslinking include, for example, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, acrylic rubber, silicone rubber, fluororubber, and urethane rubber.

[0102] 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 olefin-based thermoplastic elastomers (TPO), vinyl chloride-based elastomers (TPVC), ester-based thermoplastic elastomers (TPC), amide-based thermoplastic elastomers (TPA), urethane-based thermoplastic elastomers (TPU), and other thermoplastic elastomers (TPZ).

[0103] If the composition of the present invention contains other polymers, the content of the other polymers is usually 100 parts by mass or less, preferably 80 parts by mass or less, based on 100 parts by mass of the total of components (A) and (D).

[0104] <Preparation of Composition> The composition of the present invention can be prepared by kneading component (A), carbon black (B), short fibers (C), component (D), and other components at a desired temperature using a kneading machine such as a mixer, kneader, or roll.

[0105] One embodiment of the composition of the present invention is prepared, for example, as follows: Component (A), carbon black (B), short fibers (C), component (D), 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 component (A) 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 it is further kneaded under predetermined heating conditions (e.g., roll temperature 30-80°C for 1-30 minutes) to homogenize (B kneading) to obtain the composition of the present invention.

[0106] The composition of the present invention, in its composition before the addition of the crosslinking agent (composition A), has a Mooney viscosity of ML at 125°C. (1+4) However, it is usually 10 to 250, preferably 10 to 100, and more preferably 10 to 50. Compositions with a Mooney viscosity within this range exhibit good post-processing quality and have excellent rubber properties.

[0107] [(Crosslinked) Molded Body, Transmission Belt] A (crosslinked) molded article can be obtained from the composition of the present invention. The composition of the present invention can be molded by thermoforming methods such as extrusion molding, injection molding, press molding, calendering, transfer molding, and foam molding. In the present invention, the crosslinking temperature of the composition is usually 140°C or higher, preferably 150 to 220°C, and more preferably 160 to 200°C. Furthermore, this crosslinking reaction can be carried out in air.

[0108] In the present invention, the (crosslinked) molded article can be suitably used as a component of a power transmission belt. For example, the composition of the present invention has high adhesive strength and Green strength suitable for moldability, and excellent belt processability. Furthermore, by using the composition of the present invention, it is possible to manufacture power transmission belt components with high rubber elasticity, abrasion resistance, heat resistance, and cold resistance.

[0109] The power transmission belt of the present invention has a (crosslinked) molded body formed from the composition of the present invention. Examples of transmission belts of the present invention include friction transmission belts such as V-belts and V-ribbed belts; and interlocking transmission belts such as timing belts. Examples of transmission belts include automobile transmission belts, motorcycle transmission belts, and general industrial machinery transmission belts. Examples of V-belts include wrapped belts and raw-edge belts.

[0110] 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. The composition of the present invention is suitably used, for example, to form the adhesive rubber portion and / or the bottom rubber portion. Specifically, a crosslinked molded portion formed from the composition of the present invention is suitably used as the adhesive rubber portion and / or the bottom rubber portion.

[0111] 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 of the present invention 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]

[0112] The present invention will be described more specifically below based on examples, but the present invention is not limited in any way to these examples. Unless otherwise specified, "parts" refers to "parts by mass". [Physical Properties of Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer] <Molar Amounts of Structural Units Derived from Ethylene, Structural Units Derived from α-Olefin, and Structural Units Derived from Non-Conjugated Polyene> The aforementioned molar amount is 1 The intensity was determined by measuring it using an H-NMR spectrometer. Details of the measurement conditions are described in International Publication No. 2015 / 122415.

[0113] <Mooney Viscosity> Mooney viscosity (ML) (1+4) The viscosity at 100°C and 125°C was measured using a Mooney viscometer (SMV202 model, Shimadzu Corporation) in accordance with JIS K6300 (1994).

[0114] Using o-dichlorobenzene-d4 / benzene-d6 (4 / 1 [v / v]) as the measurement solvent, at a measurement temperature of 120°C, 13 The 1C-NMR spectrum (100 MHz, JEOL ECX400P) was measured and calculated based on the following formula (i). B value=([EX]+2[Y]) / [2×[E]×([X]+[Y])]···(i) Here, [E], [X], and [Y] represent the mole fractions of structural units derived from ethylene [A1], α-olefins with 4 to 20 carbon atoms [A2], and non-conjugated polyenes [A3], respectively, and [EX] represents the ethylene [A1]-α-olefins with 4 to 20 carbon atoms [A2] dyad chain fraction.

[0115] [Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer (A)] (1) Following the description in [Synthesis Example C1] of International Publication No. 2015 / 122415, an ethylene / 1-butene / 5-ethylidene-2-norbornene (ENB) copolymer having the following properties was obtained. Hereinafter, this will be referred to as "EBDM-1". The composition and properties of EBDM-1 are as follows: 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 Mooney Viscosity ML (1+4) 125℃:22 B value: 1.3

[0116] (2) Following the description in [Synthesis Example C1] of International Publication No. 2015 / 122415, an ethylene / 1-butene / 5-ethylidene-2-norbornene (ENB) copolymer having the following properties was obtained. Hereinafter, this will be referred to as "EBDM-2". The composition and properties of EBDM-2 are as follows: Ethylene-derived structural units: 67.8 mol% Structural units derived from 1-butene: 30.7 mol% Structural units derived from ENB: 1.5 mol% Mooney Viscosity ML (1+4) 100℃:70 Mooney Viscosity ML (1+4) 125℃: 50 B value: 1.3

[0117] [Ethylene·α-Olefin Copolymer (D)] (1) Ethylene-1-butene copolymer (hereinafter referred to as "EBR-1") Density: 862kg / m 3 Melting point <50℃, MFR: 1.2g / 10min [Mitsui Chemicals, Ltd., product name Toughmer (registered trademark) DF610]. (2) Ethylene-1-butene copolymer (hereinafter referred to as "EBR-2") Density: 864kg / m 3 Melting point <50℃, MFR: 3.6g / 10min [Mitsui Chemicals, Ltd., product name Toughmer (registered trademark) DF640].

[0118] [Example 1] Using a MIXTRON BB MIXER (manufactured by Kobe Steel, Ltd., BB-2 type, volume 1.7L, rotor 2WH), 80 parts EBDM-1 and 20 parts EBR-1 were mixed with 15 parts FN-66-3 (nylon short fibers, 3mm) as short fibers, 3 parts ZnO#1 and 2 types of zinc oxide (JIS standard (K-1410)) and 3 parts MgO#150 as crosslinking aids, 0.5 parts stearic acid as a processing aid, 100 parts Asahi #60UG as carbon black, and 14 parts Diana Process Oil PW-380 (paraffin-based process oil) as a softener. The mixture was then kneaded to obtain formulation 1.

[0119] 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.

[0120] Next, after confirming that the temperature of formulation 1 reached 40°C, formulation 1 was kneaded using a 6-inch roll to add 7 parts of zinc methacrylate (ZMA) and 7 parts of perhexa 25B-40 [2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane] as a crosslinking agent to obtain formulation 2.

[0121] 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 to obtain formulation 2.

[0122] A cross-linked sheet with a thickness of 2 mm was prepared by pressing compound 2 at 170°C for 15 minutes using a press molding machine. The obtained cross-linked sheet was subjected to hardness tests, tensile tests, and heat aging resistance tests, as described below.

[0123] [Examples 2 - 3 and Comparative Examples 1 - 2] The procedure was the same as in Example 1, except that it was based on the composition and curing system described in Table 2. The materials used in the examples and comparative examples are shown in Table 1 below.

[0124] [Table 1]

[0125] [Unvulcanized Physical Property Test; Composition Viscosity] Formula 1 Mooney viscosity ML (1+4) The viscosity at 125°C was measured using a Mooney viscometer (SMV202 model, Shimadzu Corporation) in accordance with JIS K6300 (1994).

[0126] [Unvulcanized Physical Property Test; Vulcanization Rate] Using compound 2, the vulcanization rate (tc90) was measured as follows using a measuring device: MDR2000P (manufactured by ALPHA TECHNOLOGIES) under measurement conditions of a temperature of 170°C and a time of 30 minutes. The torque change obtained under constant temperature and constant shear rate conditions was measured. The difference between the minimum torque S'min [dNm] and the maximum torque S'max [dNm]: S'max-S'min [dNm], the time it took for the torque of the measured sample to increase by 1 [dNm] after reaching the minimum torque S'min: TS1 [min], the time it took for the torque of the measured sample to reach 90% [min], with the minimum torque S'min set as 0% and the maximum torque S'max set as 100%: tc90, and MCR [dNm / min] were determined.

[0127] [Unvulcanized Physical Property Test; Green Strength (GS; 10°C)] Compound 2 was press-molded using a 3mm thick mold at 150°C for 3 minutes, and then further press-molded using a 2mm thick mold at 50°C for 120 minutes to obtain an unvulcanized sheet with a thickness of 2mm. The obtained unvulcanized sheet was subjected to a tensile test in accordance with JIS K6251, under conditions of a measurement temperature of 23°C and a tensile speed of 500 mm / min, and a 25% modulus (M) was obtained. 25 ), 50% modulus (M 50 ), strength at break (T B ) and elongation at break (E B ) was measured.

[0128] [Unvulcanized Physical Property Test; Probe Tack Test] Probe tack was measured for formulation 2 using a RHESCA TAC-II in accordance with JIS Z3284. The conditions were: temperature 23°C and 40°C, immersion speed: 120 mm / min, preload: 600 gf, test speed: 120 mm / min, and press time: 60 s.

[0129] [Hardness Test (Durometer-A)] The flat portions of the aforementioned 2 mm thick crosslinked sheets were stacked to form a 12 mm thick sheet, and its hardness (JIS-A) was measured in accordance with JIS K6253.

[0130] [Tensile Test: Modulus, Tensile Breakpoint Stress, Tensile Breakpoint Elongation] A 2mm thick crosslinked sheet was punched out to prepare 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, and the 25% modulus (M) was determined. 25 ), tensile fracture stress (T B ) and tensile elongation at fracture (E B ) was measured.

[0131] [Tear Strength] A 150mm x 50mm test specimen was cut from the aforementioned 2mm thick cross-linked sheet. A 75mm long slit was then made in the center of the specimen in the longitudinal direction, and the tear strength was measured using a tensile testing machine (tensile speed: 200mm / min, measurement ambient temperature: 23℃). The tear strength (N) was defined as the tear strength divided by the sheet thickness (mm). The test was performed three times, and the average value was adopted.

[0132] [Heat Resistance Test (Heat Aging Resistance Test)] A 2mm thick crosslinked sheet was subjected to a thermal aging test by holding it at 140°C for 72 hours in accordance with JIS K6257. The hardness of the sheet after the thermal aging test was measured. 25 , T B and E B This was measured using the same method as for the hardness test and tensile test described above.

[0133] [Table 2]

[0134] As is clear from the results above, Examples 1-3 showed a superior balance of viscosity, tackiness, and Green strength suitable for moldability compared to Comparative Examples 1-3. In particular, the improvement in both probe tack and Green strength was an unexpected result.

Claims

1. 40 to 90 parts by mass of an ethylene-α-olefin-non-conjugated polyene copolymer (A) having structural units derived from ethylene [A1], structural units derived from α-olefin having 4 to 20 carbon atoms [A2], and structural units derived from non-conjugated polyene [A3], and satisfying the following requirements (1) to (3): Carbon black (B) 0.1 to 200 parts by mass, Short fibers (C) 0.1 to 100 parts by mass, 10 to 60 parts by mass of ethylene-α-olefin copolymer (D) consisting only of structural units derived from ethylene and structural units derived from α-olefins having 3 to 20 carbon atoms, and A transmission belt composition containing (provided that the total of components (A) and (D) is 100 parts by mass): (1) The molar ratio [[A1] / [A2]] of structural units derived from ethylene [A1] to structural units derived from α-olefins [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10; (2) The content of structural units derived from non-conjugated polyene [A3] is 0.1 to 6.0 mol%, with the total of structural units derived from [A1], [A2], and [A3] being 100 mol%; (3) The B value expressed by the following formula (i) is 1.20 or higher. B value = ([EX]+2[Y]) / [2×[E]×([X]+[Y])]...(i) [Here, [E], [X], and [Y] represent the mole fractions of structural units derived from ethylene [A1], α-olefins with 4 to 20 carbon atoms [A2], and non-conjugated polyenes [A3], respectively, and [EX] represents the ethylene [A1]-α-olefins with 4 to 20 carbon atoms [A2] dyad chain fraction.]

2. The transmission belt composition according to claim 1, wherein the structural units derived from the α-olefin [A2] having 4 to 20 carbon atoms in the copolymer (A) include structural units derived from 1-butene.

3. The transmission belt composition according to claim 1 or 2, wherein the short fiber (C) is an aramid fiber.

4. The ethylene-α-olefin-non-conjugated polyene copolymer (A) further satisfies the requirement of (4) below, the transmission belt composition according to any one of claims 1 to 3: (4) Mooney viscosity at 100°C (ML) (1+4) 100°C corresponds to 5-150°C.

5. A transmission belt composition according to any one of claims 1 to 4, further comprising a crosslinking aid having two or more ethylenically double bonds.

6. The transmission belt composition according to any one of claims 1 to 5, wherein the ethylene-α-olefin copolymer (D) is an ethylene-1-butene copolymer.

7. A molded article formed from the transmission belt composition according to any one of claims 1 to 6.

8. A crosslinked molded article formed from the transmission belt composition according to any one of claims 1 to 6.

9. A transmission belt comprising the molded body described in claim 7 or the crosslinked molded body described in claim 8.

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