Vibration-damping rubber composition and its uses

Abstract

Provided is a vibration-damping rubber composition that is excellent in processability and vibration-damping properties in a low-temperature atmosphere. [Solution] A vibration-damping rubber composition comprising an ethylene-α-olefin-non-conjugated polyene copolymer (A) having structural units derived from ethylene [A1], structural units derived from an α-olefin [A2] having 4 to 20 carbon atoms, and structural units derived from a non-conjugated polyene [A3], wherein the α-olefin [A2] having 4 to 20 carbon atoms contains 1-butene, and satisfying the following requirements (1) and (2): requirement (1) the ratio [[e] / [x]] of the molar fraction [e] of the structural units derived from ethylene [A1] to the molar fraction [x] of the structural units derived from the α-olefin [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10; and requirement (2) the intrinsic viscosity [η] measured in decalin at 135°C is 5.0 to 7.0 dl / g.

Description

[Technical Field]

[0001] The present invention relates to a vibration-damping rubber composition and its use. [Background technology]

[0002] Vibration-damping rubber, which suppresses various vibrations, is widely used in automobiles, housing, industrial equipment, electrical equipment, etc. In recent years, due to the demand for heat resistance, etc., peroxide-crosslinked ethylene-propylene-diene copolymer (EPDM) has become widely used as a rubber material.

[0003] Vibration-damping rubber is required to have damping performance (vibration isolation performance) and other performances, and various developments have been made to date. For example, Patent Document 1 describes that an EPDM composition containing oil-extended EPDM, low-viscosity EPDM, and a predetermined amount of dicumyl peroxide, or a predetermined amount of dicumyl peroxide and sulfur, has excellent heat resistance and can effectively prevent a decrease in the damping coefficient, strength, elongation, etc. at high temperatures.

[0004] Patent Document 2 discloses a composition in which two specific types of olefin polymers are blended with EPDM or the like, and states that this composition can be used to produce vulcanized rubber that is excellent in vibration damping properties, low-temperature flexibility, etc.

[0005] Patent Document 3 describes that an EPDM composition having a predetermined glass transition temperature (Tg) has excellent vibration-damping properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-143905 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-29654 [Patent Document 3] Japanese Patent Application Publication No. 2018-2959 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in response to the growing demand for further improvements in the performance of conventional EPDM vibration-damping rubber, there was room for further improvement in terms of processability (flexibility) and vibration-damping properties in low-temperature environments. Therefore, an object of the present invention is to provide a vibration-damping rubber composition that is excellent in processability and vibration-damping properties in a low-temperature atmosphere. [Means for solving the problem]

[0008] As a result of extensive research aimed at solving the above problems, the present inventors have found that the above problems can be solved by the following embodiments, and have completed the present invention.

[0009] [1] A polymer having a structural unit derived from ethylene [A1], a structural unit derived from an α-olefin having 4 to 20 carbon atoms [A2], and a structural unit derived from a non-conjugated polyene [A3], the α-olefin [A2] having 4 to 20 carbon atoms includes 1-butene, and an ethylene-α-olefin-non-conjugated polyene copolymer (A) that satisfies the following requirements (1) and (2): a reinforcing agent (B); Crosslinker (C) A vibration-damping rubber composition comprising: Requirement (1): The ratio [e] / [x] of the molar fraction [e] of structural units derived from ethylene [A1] to the molar fraction [x] of structural units derived from an α-olefin [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10 (where the total of the structural units derived from [A1], [A2] and [A3] is 100 mol %). Requirement (2): The intrinsic viscosity [η] measured in decalin at 135°C is 5.0 to 7.0 dl / g.

[0010] [2] The vibration-damping rubber composition according to [1] above, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (A) satisfies the following requirement (3): Requirement (3): The molar fraction [y] of the structural unit derived from the non-conjugated polyene [A3] is 0.1 to 6.0 mol %.

[0011] [3] The vibration-damping rubber composition according to [1] or [2] above, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (A) satisfies the following requirement (4): Requirement (4): The B value represented by the following formula (i) is 1.20 or more. 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-olefin [A2] having 4 to 20 carbon atoms, and non-conjugated polyene [A3], respectively, and [EX] represents the fraction of ethylene [A1]-α-olefin [A2] having 4 to 20 carbon atoms dyad chains.)

[0012] [4] The vibration-damping rubber composition according to any one of [1] to [3], which contains 50 to 150 parts by mass of a softener per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and any polymer components other than the ethylene-α-olefin-non-conjugated polyene copolymer (A) that are optionally blended.

[0013] [5] The vibration-damping rubber composition according to any one of [1] to [4], wherein the non-conjugated polyene [A3] contains only one partial structure represented by a structural formula selected from the group consisting of the following partial structural formulas (I) and (II) in one molecule: [ka]

[0014] [6] The vibration-damping rubber composition according to any one of the above [1] to [5], wherein the non-conjugated polyene [A3] contains 5-ethylidene-2-norbornene.

[0015] [7] The vibration-damping rubber composition according to any one of [1] to [6], wherein the reinforcing agent (B) contains carbon black.

[0016] [8] The vibration-damping rubber composition according to any one of [1] to [7], wherein the content of the reinforcing agent (B) is 1 to 150 parts by mass per 100 parts by mass of the copolymer (A).

[0017] [9] The vibration-damping rubber composition according to any one of [1] to [8], wherein the crosslinking agent (C) contains a sulfur-based crosslinking agent.

[0018]

[10] A crosslinked product of the vibration-damping rubber composition according to any one of [1] to [9] above.

[0019]

[11] A vibration-damping rubber product comprising the crosslinked body according to

[10] . [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a vibration-damping rubber composition that is excellent in processability and vibration-damping properties in a low-temperature atmosphere. DETAILED DESCRIPTION OF THE INVENTION

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

[0022] <Vibration-damping rubber composition> The vibration-damping rubber composition of the present invention contains an ethylene-α-olefin-non-conjugated polyene copolymer (A), a reinforcing agent (B), and a crosslinking agent (C).

[0023] <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 having 4 to 20 carbon atoms [A2], and a structural unit derived from a non-conjugated polyene [A3], the structural units derived from the α-olefin [A2] having 4 to 20 carbon atoms include structural units derived from 1-butene, And meet the following requirements (1) and (2).

[0024] <Requirement (1)> The ratio [e] / [x] of the molar fraction [e] of structural units derived from ethylene [A1] to the molar fraction [x] of structural units derived from an α-olefin [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10, preferably 45 / 55 to 90 / 10, more preferably 50 / 50 to 85 / 15, even more preferably 55 / 45 to 80 / 20, and particularly preferably 60 / 40 to 75 / 25 (wherein the sum of the molar fractions of structural units derived from [A1], [A2], and [A3] is 100 mol %).

[0025] It is preferable that the ratio [e] / [x] of the molar fraction [e] of the structural units derived from ethylene [A1] to the molar fraction [x] of the structural units derived from α-olefin [A2] is within the above range, in terms of excellent mechanical properties and vibration damping properties in a low-temperature atmosphere.

[0026] <Requirement (2)> The intrinsic viscosity [η] measured in decalin at 135°C is 5.0 to 7.0 dL / g, preferably 5.5 to 6.5 dL / g, more preferably 5.6 to 6.3 dL / g, and particularly preferably 5.6 to 6.0 dL / g. The measurement conditions can be those in the examples described later. When the intrinsic viscosity [η] is within the above range, the copolymer (A) is preferred in terms of excellent oil retention and mechanical properties.

[0027] The ethylene-α-olefin-non-conjugated polyene copolymer (A) preferably further satisfies at least one of the following requirements (3) and (4):

[0028] <Requirement (3)> The molar fraction [y] of the structural units derived from the non-conjugated polyene [A3] is preferably 0.1 to 6.0 mol %, more preferably 0.3 to 4.0 mol %, even more preferably 0.5 to 3.0 mol %, particularly preferably 0.7 to 2.0 mol %, and even more preferably 1.0 to 1.5 mol % (wherein the sum of the molar fractions of the structural units derived from [A1], [A2] and [A3] is 100 mol %).

[0029] If the molar fraction [y] of the structural unit derived from the non-conjugated polyene [A3] is within the above range, it is preferable in terms of having sufficient crosslinkability and excellent mechanical properties.

[0030] In the above requirements (1) and (3), the mole fractions ([e], [x], and [y]) of the structural units derived from ethylene [A1], the structural units derived from α-olefin [A2], and the structural units derived from non-conjugated polyene [A3] are: 1 It can be determined by measuring the H-NMR spectrum and measuring the intensity.

[0031] <Requirement (4)> The B value represented by the following formula (i) is preferably 1.20 or more, more preferably 1.20 to 1.80, and even more preferably 1.22 to 1.40. B value=([EX]+2[Y]) / [2×[E]×([X]+[Y])]···(i) Here, [E], [X], and [Y] represent the molar fractions of structural units derived from ethylene [A1], α-olefins having 4 to 20 carbon atoms [A2], and non-conjugated polyenes [A3], respectively, and [EX] represents the ethylene [A1]-α-olefins having 4 to 20 carbon atoms [A2] dyad chain fraction. The α-olefin [A2] having 4 to 20 carbon atoms and the non-conjugated polyene [A3] may each be used alone or in combination of two or more.

[0032] Furthermore, if the B value is within the above range, the monomer units constituting the ethylene-α-olefin-non-conjugated polyene copolymer (A) have a high degree of alternation and low crystallinity, which is preferable in terms of improving processability.

[0033] The B value specified in requirement (4) is an index showing the randomness of the sequence distribution of the copolymerization monomers in the ethylene-α-olefin-non-conjugated polyene copolymer (A), and [E], [X], [Y], and [EX] in the above formula (i) are 13 The C-NMR spectrum can be measured and determined based on reports such as J.C.Randall Macromolecules, 15, 353 (1982) and J. Ray Macromolecules, 10, 773 (1977).

[0034] [α-Olefin [A2]] The ethylene-α-olefin-non-conjugated polyene copolymer (A) contains 1-butene as the α-olefin [A2] having 4 to 20 carbon atoms, and may optionally further contain structural units derived from at least one or more α-olefins having 5 to 20 carbon atoms. The proportion of 1-butene in the α-olefin [A2] having 4 to 20 carbon atoms is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more, and the upper limit thereof is, for example, 100 mol %. When the ethylene-α-olefin-non-conjugated polyene copolymer (A) contains a structural unit derived from 1-butene, it is preferable in that it has excellent vibration-damping properties in a low-temperature atmosphere.

[0035] Examples of α-olefins having 5 to 20 carbon atoms that may be used in combination include 1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene, which have a straight-chain structure without a side chain, as well as 1-nonadecene having 19 carbon atoms and 1-eicosene having 20 carbon atoms, and 4-methyl-1-pentene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene, which have a side chain. As the α-olefin having 5 to 20 carbon atoms that may be used in combination, an α-olefin having 5 to 10 carbon atoms is preferred, and 1-hexene, 1-octene, and the like are particularly preferred.

[0036] [Non-conjugated polyene [A3]] In the present invention, the non-conjugated polyene [A3] preferably contains only one partial structure represented by a structural formula selected from the group consisting of the following partial structural formulas (I) and (II) in one molecule:

[0037] [ka]

[0038] Specific 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, and cyclic non-conjugated dienes such as cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, and 5- isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, and the trienes 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.

[0039] These non-conjugated polyenes [A3] can be used singly or in combination of two or more. 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, and cyclic non-conjugated dienes are more preferred, with 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene being even more preferred.

[0040] Examples of the ethylene-α-olefin-non-conjugated polyene copolymer (A) include ethylene-1-butene-1,4-hexadiene copolymer, ethylene-1-butene-1-octene-1,4-hexadiene copolymer, ethylene-1-butene-5-ethylidene-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, and ethylene-1-butene-1-octene-5-ethylidene-2-norbornene-5-vinyl-2-norbornene copolymer.

[0041] The copolymer (A) may contain structural units derived from one or more biomass-derived monomers (biomass-derived ethylene [A1], C4-20 α-olefin [A2], and non-conjugated polyene [A3]). The copolymer (A) may contain structural units derived from one or more chemically recycled monomers (chemically recycled ethylene [A1], C4-20 α-olefin [A2], and non-conjugated polyene [A3]).

[0042] <Method for producing ethylene-α-olefin-non-conjugated polyene copolymer (A)> The ethylene-α-olefin-non-conjugated polyene copolymer (A) can be produced, for example, by employing the production method using a metallocene catalyst described in WO 2015 / 122415.

[0043] <Reinforcing agent (B)> Examples of the reinforcing agent (B) include carbon black, carbon black surface-treated with a silane coupling agent, silica, calcium carbonate, activated calcium carbonate, finely divided talc, and finely divided silicic acid.

[0044] Examples of carbon black that can be used include SRF, GPF, FEF, MAF, HAF, ISAF, SAF, FT, MT, etc. Examples of carbon black include trade names of SEAST GV, SEAST G-SVH, SEAST G-116, SEAST G-SO, SEAST GS, SEAST G-FY, and SEAST G-TA manufactured by Tokai Carbon Co., Ltd.

[0045] Examples of silica include fumed silica, precipitated silica, etc. These silicas may be surface-treated with a reactive silane such as mercaptosilane, aminosilane, hexamethyldisilazane, chlorosilane, or alkoxysilane, or a low-molecular-weight siloxane.

[0046] The content of the reinforcing agent (B) is generally 1 to 150 parts by mass, preferably 30 to 100 parts by mass, and more preferably 40 to 70 parts by mass, relative to 100 parts by mass of the copolymer (A).

[0047] <Crosslinking agent (C)> Examples of the crosslinking agent (C) include crosslinking agents commonly used in crosslinking rubber, such as organic peroxides, phenolic resins, sulfur-based crosslinking agents, hydrosilicone compounds, amino resins, quinone or its derivatives, amine compounds, azo compounds, epoxy compounds, isocyanate compounds, etc. Among these, organic peroxides and sulfur-based crosslinking agents (hereinafter also referred to as "vulcanizing agents") are preferred.

[0048] <Organic peroxide> Examples of organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

[0049] When an organic peroxide is used as the crosslinking agent (C), the amount thereof in the vibration-damping rubber composition is generally 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the copolymer (A). When the amount of the organic peroxide is within the above range, it is preferable because the vibration-damping rubber composition exhibits excellent crosslinking properties without blooming on the surface of the vibration-damping rubber.

[0050] <Crosslinking aid> When an organic peroxide is used as the crosslinking agent (C), it is preferable to use a crosslinking aid in combination. Examples of crosslinking aids include sulfur; quinone dioxime crosslinking aids such as p-quinone dioxime; acrylic crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyl crosslinking aids such as diallyl phthalate and triallyl isocyanurate; maleimide crosslinking aids; divinylbenzene; and metal oxides such as zinc oxide (e.g., ZnO#1 / zinc oxide type 2 (JIS K-1410 (2006), manufactured by Hakusui Tech Co., Ltd.)), zinc oxide (e.g., "META-Z102" (trade name, manufactured by Inoue Lime Industry Co., Ltd.)), and magnesium oxide.

[0051] When a crosslinking aid is used, the amount of the crosslinking aid blended in the vibration-damping rubber composition is usually 0.01 to 10 parts by mass, preferably 0.05 to 7 parts by mass, and more preferably 0.075 to 5 parts by mass per part by mass of the organic peroxide.

[0052] <Sulfur-based crosslinking agent> Examples of sulfur-based crosslinking agents (vulcanizing agents) include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dithiocarbamate.

[0053] When a sulfur-based crosslinking agent is used as the crosslinking agent (C), the amount thereof in the vibration-damping rubber composition is usually 0.1 to 10 parts by mass, preferably 0.12 to 7.0 parts by mass, and more preferably 0.15 to 5.0 parts by mass, per 100 parts by mass of the copolymer (A). When the amount of the sulfur-based crosslinking agent is within the above range, there is no blooming on the surface of the obtained vibration-damping rubber, and the vibration-damping rubber composition exhibits excellent crosslinking properties.

[0054] <Vulcanization accelerator> When a sulfur-based crosslinking agent is used as the crosslinking agent (C), it is preferable to use a vulcanization accelerator in combination. Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole (e.g., Suncerer M (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), 2-(4-morpholinodithio)benzothiazole (e.g., Noccelaer MDB-P (trade name; manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)), 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-dinitrophenyl)mercaptobenzothiazole, Thiazole-based vulcanization accelerators such as ethyl-4-morpholinothio)benzothiazole and dibenzothiazyl disulfide (e.g., Sancerer DM (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); guanidine-based vulcanization accelerators such as diphenylguanidine, triphenylguanidine, and diorthotolylguanidine; aldehyde-amine-based vulcanization accelerators such as acetaldehyde-aniline condensation product and butyraldehyde-aniline condensation product; imidazoline-based vulcanization accelerators such as 2-mercaptoimidazoline; tetramethylthiuram monosulfide (e.g., Sancerer DM (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); thiuram-based vulcanization accelerators such as Sancerer TS (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetramethylthiuram disulfide (e.g., Sancerer TT (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetraethylthiuram disulfide (e.g., Sancerer TET (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), tetrabutylthiuram disulfide (e.g., Sancerer TBT (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), and dipentamethylenethiuram tetrasulfide (e.g., Sancerer TRA (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)); zinc dimethyldithiocarbamate, diethyldithio Examples of such vulcanization accelerators include dithioacid salt vulcanization accelerators such as zinc carbamate, zinc dibutyldithiocarbamate (for example, Sancerar PZ, Sancerar BZ, and Sancerar EZ (trade names; manufactured by Sanshin Chemical Industry Co., Ltd.)) and tellurium diethyldithiocarbamate; thiourea-based vulcanization accelerators such as ethylenethiourea (for example, Sancerar BUR (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.), Sancerar 22-C (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), N,N'-diethylthiourea, and N,N'-dibutylthiourea; and xanthate-based vulcanization accelerators such as zinc dibutylxatogenate.

[0055] When a vulcanization accelerator is used, the amount of the vulcanization accelerator in the vibration-damping rubber composition is generally 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of copolymer (A). When the amount of the vulcanization accelerator is within the above range, no blooming occurs on the surface of the resulting vibration-damping rubber, and the vibration-damping rubber composition exhibits excellent crosslinking properties.

[0056] When a sulfur-based crosslinking agent is used as the crosslinking agent (C), a vulcanization aid can be used in combination. Examples of the vulcanization aid include zinc oxide (e.g., "ZnO#1 / Zinc Oxide Type 2" (trade name; manufactured by Hakusui Tech Co., Ltd.), "META-Z102" (trade name; manufactured by Inoue Lime Industry Co., Ltd.), and magnesium oxide. When a vulcanization aid is used, the amount of the vulcanization aid blended in the vibration-damping rubber composition is usually 1 to 20 parts by mass per 100 parts by mass of the copolymer (A).

[0057] <Other ingredients> The composition of the present invention may further contain components other than the copolymer (A), reinforcing agent (B), and crosslinking agent (C) (hereinafter also referred to as "other components") depending on the purpose, such as at least one selected from softeners, antioxidants, processing aids, activators, moisture absorbents, antistatic agents, colorants, lubricants, and thickeners. The composition of the present invention may further contain polymers other than the copolymer (A) (hereinafter also referred to as "other polymers"), such as elastomers and / or rubbers. Each of the components described below may be used alone or in combination of two or more.

[0058] <Softener> Specific examples of softeners include petroleum-based softeners such as paraffin oil (e.g., paraffin-based process oil), naphthenic process oil, lubricating oil, liquid paraffin, petroleum asphalt, and Vaseline; coal tar-based softeners such as coal tar; fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; waxes such as beeswax and carnauba wax; fatty acids or salts thereof such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, and calcium stearate; naphthenic acid, pine oil, rosin, and derivatives thereof; synthetic polymeric substances such as terpene resins, petroleum resins, and coumarone-indene resins; ester-based softeners such as dioctyl phthalate and dioctyl adipate; and other softeners such as microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricating oils, tall oil, and sub(factice). Of these, petroleum-based softeners are preferred, and paraffin oil is particularly preferred.

[0059] The amount of the softener in the composition of the present invention is generally 5 to 200 parts by mass, preferably 50 to 180 parts by mass, per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and any polymer (elastomer, rubber, etc.) components added as an optional component.

[0060] <Anti-aging agent (stabilizer)> The life of a molded article formed from the composition of the present invention can be extended by incorporating an antioxidant (stabilizer). Examples of such antioxidants include conventionally known antioxidants, such as amine-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants.

[0061] These antioxidants can be used alone or in combination of two or more, and the blending amount is usually 0.3 to 10 parts by mass, preferably 0.5 to 7.0 parts by mass, per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and other polymers (elastomers, rubbers, etc.). By adjusting the blending amount within this range, no bloom occurs on the surface of a molded article obtained from the resulting vibration-damping rubber composition, and furthermore, vulcanization inhibition can be suppressed.

[0062] <Processing aids> As the processing aid, a wide variety of processing aids that are generally compounded in rubber can be used.

[0063] The amount of the processing aid to be blended is usually 10 parts by mass or less, preferably 8.0 parts by mass or less, per 100 parts by mass of the total of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and other polymers (elastomers, rubbers, etc.) contained in the composition of the present invention.

[0064] <Activator> Specific examples of surfactants include amines such as di-n-butylamine, dicyclohexylamine, and monoethanolamine; diethylene glycol, polyethylene glycol, lecithin, triaryl methylate, zinc compounds of aliphatic or aromatic carboxylic acids; zinc peroxide preparations; octadecyltrimethylammonium bromide, synthetic hydrotalcite, and special quaternary ammonium compounds.

[0065] When an activator is contained, the amount thereof is usually 0.2 to 10 parts by mass, preferably 0.3 to 5 parts by mass, per 100 parts by mass of the total of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and other polymers (elastomers, rubbers, etc.).

[0066] <Other polymers> The composition of the present invention may contain a polymer (also referred to as "other polymer") other than the copolymer (A) (e.g., an elastomer or rubber). When the composition contains the other polymer, the amount of the other polymer is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A). The composition of the present invention may contain an ethylene-propylene-non-conjugated diene copolymer as the other polymer.

[0067] <Preparation of Composition> The composition of the present invention can be prepared by kneading the ethylene-α-olefin-non-conjugated polyene copolymer (A), the reinforcing agent (B), the crosslinking agent (C), and other components that are added as needed, at a desired temperature (e.g., 80°C to 200°C) using a kneading machine such as a mixer, kneader, or roll. The ethylene-α-olefin-non-conjugated polyene copolymer (A) has excellent kneadability, allowing for the successful preparation of a vibration-damping rubber composition.

[0068] In order to fully utilize the improved cold resistance and roll processability of the ethylene-α-olefin-non-conjugated polyene copolymer (A) while maintaining the high strength of the copolymer, when the copolymer (A) is oil-extended and used as a raw material, the amount of oil extension is preferably 50 to 150 parts by mass per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A).

[0069] <Molded body> Molded articles obtained from the vibration-damping rubber composition of the present invention, such as crosslinked molded articles and crosslinked foamed articles, can be used in a variety of applications.

[0070] Specific examples of such molded articles include tire rubber, O-rings, industrial rolls, packing (e.g., condenser packing), gaskets, belts (e.g., heat insulation belts, copier belts), hoses (e.g., water hoses, brake reservoir hoses, radiator hoses), waterproof rubber, sponges (e.g., weatherstrip sponges, heat insulation sponges, protect sponges, micro-foam sponges), cables (ignition cables, cab tire cables, high-tension cables), electric wire coating materials (high-voltage electric wire coating materials, low-voltage electric wire coating materials, marine electric wire coating materials), glass run channels, color skin materials, paper feed rolls, roofing sheets, and the like, and these articles are used in a wide range of applications. [Example]

[0071] The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples in any way.

[0072] <Production of copolymer> [Manufacturing Example 1] A polymerization reaction of ethylene, 1-butene, and 5-ethylidene-2-norbornene (ENB) was carried out continuously at 75°C using a 300 L volume polymerization vessel equipped with a stirring blade.

[0073] Hexane (feed rate: 46.5 L / h) was used as the polymerization solvent and continuously supplied to the polymerization reactor so that the ethylene feed rate was 4.2 kg / h, the 1-butene feed rate was 9.8 kg / h, the ENB feed rate was 612 g / h, and the hydrogen feed rate was 3.4 NL / h.

[0074] While maintaining the polymerization pressure at 1.7 MPaG and the polymerization temperature at 75°C, [bis(4-methoxyphenyl)methylene(η5-cyclopentadienyl)(η5-2,3,6,7-tetramethylfluorenyl)]hafnium dimethyl was used as the main catalyst and continuously fed to the polymerization reactor at a feed rate of 0.006 mmol / h. Furthermore, triphenylcarbenium tetrakis(pentafluorophenyl)borate as a cocatalyst was continuously fed to the polymerization reactor at a feed rate of 0.038 mmol / h, and triisobutylaluminum as an organoaluminum compound was continuously fed at a feed rate of 13 mmol / h.

[0075] In this way, a solution containing 5.7% by mass of ethylene-1-butene-ENB copolymer (A1) formed from ethylene, 1-butene, and ENB was obtained. A small amount of methanol was added to the solution withdrawn from the bottom of the polymerization reactor to terminate the polymerization reaction. 60 parts by mass of paraffin oil (Idemitsu Kosan Co., Ltd., product name: Diana Process Oil PW-100) was added to 100 parts by mass of ethylene-1-butene-ENB copolymer (A1), and the ethylene-1-butene-ENB copolymer (A1) was separated from the solvent by steam stripping and then dried under reduced pressure at 80°C overnight.

[0076] By the above procedure, ethylene-1-butene-ENB copolymer (A1) formed from ethylene, butene, and ENB was obtained at a rate of 2.5 kg / h. Its intrinsic viscosity [η] was 5.8 g / dl.

[0077] [Manufacturing Example 2] Ethylene-propylene-5-ethylidene-2-norbornene copolymer (A2) (manufactured by Mitsui Chemicals, Inc., trade name: 4100E, intrinsic viscosity [η]: 4.0 dl / g, Mooney viscosity (ML (1+4) 125℃):72) was prepared.

[0078] [Table 1]

[0079] [Example 1] Using a batch mixer (Kobe Steel, Ltd.: BB-1800 Mixtron Mixer, volume 1.63 L), 100 parts by mass of the copolymer (A1) obtained in Production Example 1, 100 parts by mass of non-conjugated polyene: 5-ethylidene-2-norbornene, non-conjugated polyene content = 3.8% by mass, 60 parts by mass of carbon black (Asahi #60UG (FEF): Asahi Carbon Co., Ltd.) as a reinforcing agent, 3 parts by mass of activated zinc oxide (META-Z102: Inoue Lime Industry Co., Ltd.) as a crosslinking aid, and 1 part by mass of stearic acid (Camellia Stearate Series: NOF Corporation) were kneaded to obtain an uncrosslinked rubber composition. The kneading was performed at a rotor rotation speed of 36 rpm for a kneading time of 5 minutes and 30 seconds.

[0080] After confirming that the temperature of the obtained uncrosslinked body had dropped to 40°C or less, the uncrosslinked body was kneaded with 0.75 parts by mass of sulfur (manufactured by Junsei Chemical Co., Ltd.) as a crosslinking agent, and 1.5 parts by mass of Sancerer PZ (manufactured by Sanshin Chemical Industry Co., Ltd.), 1.5 parts by mass of Sancerer TT (manufactured by Sanshin Chemical Industry Co., Ltd.), and 0.5 parts by mass of Sancerer TM (manufactured by Sanshin Chemical Industry Co., Ltd.) as vulcanization accelerators using a 6-inch roll (manufactured by Nippon Roll Co., Ltd.) to obtain a compound. The roll temperatures for the front roll / rear roll were 50°C / 50°C, and the roll rotation speeds for the front roll / rear roll were 15 rpm / 18 rpm.

[0081] Next, this compound was crosslinked for 10 minutes at 170°C using a press molding machine to prepare 2mm and 1mm thick crosslinked sheets. The 2mm thick sheets were used for hardness and tensile tests, and the 1mm thick sheets were used for tensile viscoelasticity tests. The physical properties of the resulting rubber composition and crosslinked product were evaluated.

[0082] [Comparative Example 1] The same procedure as in Example 1 was carried out except that the ethylene-α-olefin-non-conjugated polyene copolymer (A1) was replaced by the copolymer (A2).

[0083] <Measurement of physical properties> [Mole fraction of structural units derived from ethylene, structural units derived from α-olefins, and structural units derived from non-conjugated polyenes] The measurement was performed using o-dichlorobenzene-d4 as the measurement solvent, under the following measurement conditions: measurement temperature 120°C, spectrum width 20 ppm, pulse repetition time 7.0 seconds, pulse width 5.00 μsec (500 MHz, Bruker Biospin, AVANCEIII cryo-500 type nuclear magnetic resonance spectrometer). 1 H-NMR spectra were measured and calculated.

[0084] [Intrinsic viscosity [η](dl / g)] To measure the intrinsic viscosity [η] (dl / g) of the copolymer, 1 g of the copolymer was shredded, and then subjected to Soxhlet extraction using methyl ethyl ketone at 80°C for 3 hours, followed by drying under reduced pressure overnight at 80°C. The intrinsic viscosity [η] (dl / g) of the copolymer was measured using a fully automatic intrinsic viscometer manufactured by Rigo Co., Ltd. at a temperature of 135°C and a measurement solvent of decalin.

[0085] [B value] The measurement solvent was o-dichlorobenzene-d4 / benzene-d6 (4 / 1 [v / v]) and the measurement temperature was 120 °C (125 MHz, Bruker Biospin AVANCEIII cryo-500 type nuclear magnetic resonance spectrometer). 13 The C-NMR spectrum was measured, and the B value was calculated based on the following formula (i). B value=([EX]+2[Y]) / [2×[E]×([X]+[Y])]···(i) [Here, [E], [X], and [Y] represent the molar fractions of structural units derived from ethylene [A1], α-olefin [A2] having 4 to 20 carbon atoms, and non-conjugated polyene [A3], respectively, and [EX] represents the ethylene [A1]-α-olefin [A2] having 4 to 20 carbon atoms dyad chain fraction.]

[0086] [Mooney viscosity (ML (1+4) 100℃)] Mooney viscosity (ML (1+4) 100°C) was measured using a Mooney viscometer (Shimadzu Corporation (SMV-301RT)) in accordance with JIS K6300-1 (2013).

[0087] [Crosslinking (vulcanization) characteristic evaluation] The resulting uncrosslinked specimen was used as a sample and the torque change obtained under constant temperature and constant shear rate conditions was measured using a vulcanization measurement device (ALPHA TECHNOLOGIES, MDR2000). From the torque change obtained, the difference between the maximum torque S'Max [dNm] and the minimum torque S'Min [dNm] (S'Max-Min) was calculated. The time tc90 [min] at which the torque of the measured specimen reached 90% (minimum torque S'Min = 0% and maximum torque S'Max = 100%) and the maximum slope MCR [dNm / min] of the vulcanization curve were calculated. The measurement conditions were a temperature of 170°C, a time of 30 minutes, and a shear rate of 100 cycles / min (1.66 Hz).

[0088] [Hardness test: Durometer A hardness (Shore A hardness)] The hardness of a 2 mm thick sheet of the crosslinked body was measured in accordance with the description of Test Type A in Section 6 "Durometer hardness test" of JIS K 6253 (2012) "Vulcanized rubber and thermoplastic rubber - Determination of hardness".

[0089] [Tensile test: modulus, tensile stress at break, tensile elongation at break] The modulus, tensile stress at break and tensile elongation at break of a 2 mm thick sheet of the crosslinked product were measured by the following methods. The sheet was punched out to prepare a No. 3 dumbbell test piece as described in JIS K 6251 (2017). A tensile test was performed using this test piece according to the method specified in JIS K6251, Section 3, at a measurement temperature of 23°C and a tensile speed of 500 mm / min, and the tensile stress at an elongation of 25% (25% modulus (M25)), tensile stress at break (TB), and tensile elongation at break (EB) were measured.

[0090] [Tensile viscoelasticity test] Storage modulus E': Dynamic viscoelasticity was measured under a nitrogen atmosphere using a TA-Instruments RSA-G2 for 1 mm crosslinked rubber sheets obtained in the Examples and Comparative Examples. Here, tan δ is the ratio of the loss modulus to the storage modulus when a sinusoidal oscillatory strain is applied to a viscoelastic material, and is the value measured in tension mode (strain 1%) in the temperature range of -70°C to 150°C, at a heating rate of 4°C / min, and at a frequency of 1 Hz.

[0091] [Table 2]

Claims

1. The copolymer 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], the α-olefin [A2] having 4 to 20 carbon atoms includes 1-butene, and an ethylene / α-olefin / non-conjugated polyene copolymer (A) that satisfies the following requirements (1) and (2): a reinforcing agent (B); a crosslinking agent (C); A vibration-damping rubber composition comprising: Requirement (1): The ratio [e] / [x] of the molar fraction [e] of structural units derived from ethylene [A1] to the molar fraction [x] of structural units derived from an α-olefin [A2] having 4 to 20 carbon atoms is 40 / 60 to 90 / 10 (where the sum of the molar fractions of the structural units derived from [A1], [A2], and [A3] is 100 mol %). Requirement (2): The intrinsic viscosity [η] measured in decalin at 135° C. is 5.0 to 7.0 dl / g.

2. The vibration-damping rubber composition according to claim 1, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (A) satisfies the following requirement (3): Requirement (3): The molar fraction [y] of the structural unit derived from the non-conjugated polyene [A3] is 0.1 to 6.0 mol %.

3. The vibration-damping rubber composition according to claim 1, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (A) satisfies the following requirement (4): Requirement (4): The B value represented by the following formula (i) is 1.20 or more. 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], C4-C20 α-olefin [A2], and non-conjugated polyene [A3], respectively, and [EX] represents the ethylene [A1]-C4-C20 α-olefin [A2] dyad chain fraction.)

4. 2. The vibration-damping rubber composition according to claim 1, comprising 50 to 150 parts by mass of a softener per 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (A) and any polymer components other than the ethylene-α-olefin-non-conjugated polyene copolymer (A), which are optionally blended.

5. 2. The vibration-damping rubber composition according to claim 1, wherein the non-conjugated polyene [A3] contains only one partial structure represented by a structural formula selected from the group consisting of the following partial structural formulas (I) and (II) in one molecule: 【Chemistry 1】

6. The vibration-damping rubber composition according to claim 1, wherein the non-conjugated polyene [A3] comprises 5-ethylidene-2-norbornene.

7. The vibration-damping rubber composition according to claim 1, wherein the reinforcing agent (B) contains carbon black.

8. 2. The vibration-damping rubber composition according to claim 1, wherein the content of said reinforcing agent (B) is 1 to 150 parts by mass per 100 parts by mass of said copolymer (A).

9. The vibration-damping rubber composition according to claim 1, wherein the crosslinking agent (C) includes a sulfur-based crosslinking agent.

10. A crosslinked body of the vibration damping rubber composition according to any one of claims 1 to 9.

11. A vibration-damping rubber product comprising the crosslinked product according to claim 10.

Images