Composition for forming a foam

Abstract

To provide a composition containing an ethylene / α-olefin / nonconjugated polyene copolymer, capable of forming a foam excellent in surface slipperiness.SOLUTION: The composition for forming a foam contains: a specific ethylene / α-olefin / nonconjugated polyene copolymer (S); a hydrosilyl group-containing compound (Y) having at least two hydrosilyl groups in one molecule; a platinum-based catalyst (Z) for hydrosilyl crosslinking; and at least one component (BA) selected from aliphatic monocarboxylic acids and metal hydroxide compounds in an amount of 5-30 pts.mass based on 100 pts.mass of the copolymer (S).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition for forming a foam.

Background Art

[0002] It is known that a molded article obtained by hydrosilyl crosslinking an ethylene·α-olefin·non-conjugated polyene copolymer (see, for example, Patent Document 1) is excellent in mechanical strength, heat aging resistance, etc. compared with sulfur vulcanization and peroxide crosslinking.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the study by the present inventors, it has been found that a foam obtained by hydrosilyl crosslinking and foaming an ethylene·α-olefin·non-conjugated polyene copolymer tends to be inferior in surface slipperiness.

[0005] An object of the present invention is to provide a composition containing an ethylene·α-olefin·non-conjugated polyene copolymer that can form a foam excellent in surface slipperiness.

Means for Solving the Problems

[0006] As a result of studying to solve the above problems, the present inventors have found that the above problems can be solved by a composition having the following configuration, and have completed the present invention. The present invention relates to, for example, the following [1] to [3].

[0007] [1] It has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene (C) containing two or more of at least one partial structure selected from the formulas (I) and (II) in total in the molecule, and an ethylene·α-olefin·non-conjugated polyene copolymer (S) that satisfies the following requirements (i) and (ii). A hydrosilyl group-containing compound (Y) having at least two hydrosilyl groups in one molecule. A platinum-based catalyst (Z) for hydrosilylation crosslinking. A composition for forming a foam, containing at least one component (BA) selected from an aliphatic monocarboxylic acid and a metal hydroxide compound in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of the copolymer (S).

[0008] [Chemical formula]

[0009] (i) The molar ratio (structural unit derived from ethylene (A) / structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms) is 40 / 60 to 99.9 / 0.1. (ii) The content ratio of the structural unit derived from the non-conjugated polyene (C) is 0.07 to 10% by mass in 100% by mass of the ethylene·α-olefin·non-conjugated polyene copolymer (S).

[0010] [2] The composition for forming a foam according to [1] above, wherein the component (BA) is an aliphatic monocarboxylic acid. [3] The composition for forming a foam according to [1] or [2] above, wherein the component (BA) is stearic acid. [Advantages of the Invention]

[0011] According to the present invention, it is possible to provide a composition containing an ethylene·α-olefin·non-conjugated polyene copolymer that can form a foam excellent in surface slipperiness. [Embodiments for Carrying Out the Invention]

[0012] A mode for carrying out the present invention will be described. [Composition for foam formation] The composition for forming a foam of the present invention (hereinafter also referred to as "the composition of the present invention") contains an ethylene·α-olefin·non-conjugated polyene copolymer (S), a hydrosilyl group-containing compound (Y) having at least two hydrosilyl groups in one molecule, a platinum-based catalyst (Z) for hydrosilyl crosslinking, and at least one component (BA) selected from aliphatic monocarboxylic acids and metal hydroxide compounds, and contains the component (BA) in the range of 5 to 30 parts by mass with respect to 100 parts by mass of the copolymer (S).

[0013] <Ethylene·α-olefin·non-conjugated polyene copolymer (S)> The ethylene·α-olefin·non-conjugated polyene copolymer (S) (hereinafter also referred to as "copolymer (S)") has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene (C). The non-conjugated polyene (C) contains two or more of at least one partial structure selected from the formulas (I) and (II) in total in the molecule.

[0014]

Chemical formula

[0015] Examples of the α-olefin (B) having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. Among these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene, and 1-octene are preferable, and propylene is more preferable.

[0016] The copolymer (S) contains a structural unit derived from at least one α-olefin (B) having 3 to 20 carbon atoms, and may contain structural units derived from two or more α-olefins (B) having 3 to 20 carbon atoms.

[0017] Examples of the non-conjugated polyene (C) include 5-vinyl-2-norbornene (VNB), norbornadiene, 1,4-hexadiene, and dicyclopentadiene. Among these, since VNB is highly available, has good hydrosilylation crosslinking, and the heat resistance of the composition is easily improved, it is preferable that the non-conjugated polyene (C) contains VNB, and it is more preferable that the non-conjugated polyene (C) is VNB.

[0018] The copolymer (S) contains a structural unit derived from at least one non-conjugated polyene (C), and may contain structural units derived from two or more non-conjugated polyenes (C). The copolymer (S) can further have a structural unit derived from a non-conjugated polyene (D) that contains only one substructure selected from the formulas (I) and (II) in the molecule.

[0019] Examples of the non-conjugated polyene (D) include 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(3-butenyl)-2-norbornene, 5-(1-methyl-2-propenyl)-2-norbornene, 5-(4-pentenyl)-2-norbornene, 5-(1-methyl-3-butenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-(2,3-dimethyl-3-butenyl)-2-norbornene, 5-(2-ethyl-3-butenyl)-2-norbornene, 5-(6-heptenyl)-2-norbornene, 5-(3-methyl-5-hexenyl)-2-norbornene, 5-(3,4-dimethyl-4-pentenyl)-2-norbornene, 5-(3-ethyl-4-pentenyl)-2-norbornene, 5-(7-octenyl)-2-norbornene, 5-(2-methyl-6-heptenyl)-2-norbornene, 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(5-ethyl-5-hexenyl)-2-norbornene, 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene. Among these, ENB is preferred because it is highly available, easy to control the crosslinking rate during hydrosilylation crosslinking, and easy to obtain good mechanical properties.

[0020] The copolymer (S) can contain a structural unit derived from at least one non-conjugated polyene (D), and may contain structural units derived from two or more non-conjugated polyenes (D). As requirement (i), in the copolymer (S), the molar ratio (structural unit derived from ethylene (A) / structural unit derived from α-olefin (B) having 3 to 20 carbon atoms) is 40 / 60 to 99.9 / 0.1, preferably 50 / 50 to 90 / 10, more preferably 55 / 45 to 85 / 15, and even more preferably 55 / 45 to 78 / 22. Such a copolymer (S) is preferred because the foam obtained by hydrosilylation crosslinking exhibits excellent rubber elasticity and is excellent in mechanical strength and flexibility.

[0021] As requirement (ii), in 100% by mass of the copolymer (S) (i.e., in the total content ratio of all constitutional units being 100% by mass), the content ratio of the constitutional units derived from the non-conjugated polyene (C) is 0.07 to 10% by mass, preferably 0.1 to 8.0% by mass, more preferably 0.5 to 5.0% by mass. Such a copolymer (S) is preferable because the foam obtained from the composition of the present invention has sufficient hardness and excellent mechanical properties, and when subjected to hydrosilylation crosslinking, it exhibits a fast crosslinking rate and is suitable for the production of the foam, thus being preferable.

[0022] In 100% by mass of the copolymer (S), the content ratio of the constitutional units derived from the non-conjugated polyene (D) is usually 0 to 20% by mass, preferably 0 to 8% by mass. The content ratios of the constitutional units derived from ethylene (A), α-olefin (B), non-conjugated polyene (C), and non-conjugated polyene (D) in the copolymer (S) 13 can be determined by C-NMR.

[0023] The Mooney viscosity ML of the copolymer (S) at 125 °C (1+4) is preferably 5 to 100, more preferably 20 to 95, and even more preferably 50 to 90. The copolymer (S) having a Mooney viscosity within the above range has good processability and fluidity, exhibits excellent rubber physical properties, and tends to show good post-treatment quality (ribbon handling property).

[0024] The Mooney viscosity is measured in accordance with JIS K6300 (1994) using a Mooney viscometer (Model SMV202 manufactured by Shimadzu Corporation). The intrinsic viscosity [η] of the copolymer (S) measured in decalin at 135 °C is preferably 0.1 to 5 dL / g, more preferably 0.5 to 5.0 dL / g, and even more preferably 0.9 to 4.0 dL / g. The copolymer (S) having [η] within the above range tends to have excellent molding processability.

[0025] [η] is specifically measured as follows. Approximately 20 mg of the copolymer (S) is dissolved in 15 mL of decalin, and the specific viscosity η is measured in an oil bath at 135 °Csp Measure it. After adding 5 mL of decalin solvent to this decalin solution for dilution, the specific viscosity η sp was measured in the same manner. This dilution operation was repeated two more times, and the value of η sp / C when extrapolating the concentration (C) to 0 was adopted as the intrinsic viscosity. [η]=lim(η sp / C) (C→0)

[0026] The copolymer (S) is obtained by copolymerizing monomers including ethylene (A), an α-olefin (B) having 3 to 20 carbon atoms, a non-conjugated polyene (C), and, if necessary, a non-conjugated polyene (D). The copolymer (S) may be prepared by any production method, but it is preferably obtained by copolymerizing the monomers in the presence of a metallocene compound, and more preferably obtained by copolymerizing the monomers in the presence of a catalyst system containing a metallocene compound. Specifically, the copolymer (S) can be produced, for example, by adopting the method described in the metallocene catalyst described in International Publication No. 2015 / 122495. The composition of the present invention can contain one or more copolymers (S).

[0027] <Compound containing hydrosilyl group (Y)> The hydrosilyl group-containing compound (Y) acts as a crosslinking agent that reacts with the copolymer (S). The hydrosilyl group-containing compound (Y) can be used in any of its structures, such as conventionally produced and commercially available resinous substances having linear, cyclic, branched, or three-dimensional network structures.

[0028] The hydrosilyl group-containing compound (Y) contains at least two hydrosilyl groups in one molecule. Examples of the hydrosilyl group-containing compound (Y) include compounds represented by the following formula. R b H c SiO (4-b-c) / 2

[0029] In the above formula, R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, excluding aliphatic unsaturated bonds. Examples of the monovalent hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, nonyl group, and decyl group; phenyl group; and halogenated alkyl groups such as trifluoropropyl group. Among these, methyl group, ethyl group, propyl group, phenyl group, and trifluoropropyl group are preferred, and methyl group and phenyl group are more preferred.

[0030] In the above formula, b satisfies 1 ≦ b < 3, preferably 1 ≦ b < 2.2, particularly preferably 1.5 ≦ b ≦ 2, c satisfies 0.6 ≦ c ≦ 3, preferably 0.6 ≦ c < 2, and b + c satisfies b + c ≦ 3, preferably b + c ≦ 2.7.

[0031] The hydrosilyl group-containing compound (Y) is, for example, an organohydrogenpolysiloxane having preferably 2 to 1000 silicon atoms, more preferably 2 to 300 silicon atoms, and even more preferably 4 to 200 silicon atoms in one molecule. Specifically, siloxane oligomers such as 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyltetracyclosiloxane, and 1,3,5,7,8-pentamethylpentacyclosiloxane; methylhydrogenpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain; dimethylsiloxane·methylhydrogensiloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain; methylhydrogenpolysiloxane blocked with silanol groups at both ends of the molecular chain; dimethylsiloxane·methylhydrogensiloxane copolymer blocked with silanol groups at both ends of the molecular chain; dimethylpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain; methylhydrogenpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain; dimethylsiloxane·methylhydrogensiloxane copolymer blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, R2(H)SiO 1 / 2 units and SiO 4 / 2 units, and optionally R3SiO 1 / 2 units, R2SiO 2 / 2 units, R(H)SiO 2 / 2 units, (H)SiO3 / 2 or RSiO 3 / 2 Examples of silicone resins that may contain units include those mentioned above.

[0032] Examples of methylhydrogenpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain include compounds represented by the following formula, and further compounds in which part or all of the methyl groups in the following formula are substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. (CH3)3SiO-(-SiH(CH3)-O-) d -Si(CH3)3 In the formula, d is an integer of 2 or more.

[0033] Examples of dimethylsiloxane-methylhydrogensiloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain include compounds represented by the following formula, and further compounds in which part or all of the methyl groups in the following formula are substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. (CH3)3SiO-(-Si(CH3)2-O-) e -(-SiH(CH3)-O-) f -Si(CH3)3 In the formula, e is an integer of 1 or more, and f is an integer of 2 or more.

[0034] Examples of dimethylpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain include compounds represented by the following formula, and further compounds in which part or all of the methyl groups in the following formula are substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. HSi(CH3)2O-(-Si(CH3)2-O-) e -Si(CH3)2H In the formula, e is an integer of 1 or more.

[0035] Examples of the methylhydrogenpolysiloxane blocked at both molecular chain ends with dimethylhydrogen siloxy groups include compounds represented by the following formula, and further compounds in which part or all of the methyl groups in the following formula are substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. HSi(CH3)2O-(-SiH(CH3)-O-) e -Si(CH3)2H In the formula, e is an integer of 1 or more.

[0036] Examples of the dimethylsiloxane·methylhydrogen siloxane copolymer blocked at both molecular chain ends with dimethylhydrogen siloxy groups include compounds represented by the following formula, and further compounds in which part or all of the methyl groups in the following formula are substituted with ethyl groups, propyl groups, phenyl groups, trifluoropropyl groups, etc. HSi(CH3)2O-(-Si(CH3)2-O-) e -(-SiH(CH3)-O-) h -Si(CH3)2H In the formula, e and h are each an integer of 1 or more.

[0037] The above compounds can be produced by known methods. For example, octamethylcyclotetrasiloxane and / or tetramethylcyclotetrasiloxane are equilibrated with a compound containing a triorganosilyl group or a diorganohydrogen siloxy group such as hexamethyldisiloxane or 1,3-dihydro-1,1,3,3-tetramethyldisiloxane that can be a terminal group in the presence of a catalyst such as sulfuric acid, trifluoromethanesulfonic acid, or methanesulfonic acid at a temperature of about -10°C to +40°C, whereby they can be easily obtained.

[0038] The composition of the present invention can contain one or more of the above compounds (Y). The content of the hydrosilyl group-containing compound (Y) in the composition of the present invention is usually 0.1 to 100 parts by mass, preferably 0.1 to 75 parts by mass, more preferably 0.1 to 50 parts by mass, still more preferably 0.2 to 30 parts by mass, 0.2 to 20 parts by mass, 0.5 to 10 parts by mass, or 0.5 to 5 parts by mass with respect to 100 parts by mass of the copolymer (S).

[0039] <Platinum-based catalyst (Z)> The platinum-based catalyst (Z) for hydrosilyl crosslinking is an addition reaction catalyst, and there is no particular limitation as long as it promotes the addition reaction (hydrosilylation reaction of alkene) between the alkenyl group of the copolymer (S) and the hydrosilyl group of the hydrosilyl group-containing compound (Y), and it can be used.

[0040] Specific platinum-based catalysts are usually known ones used for the curing of addition-curing types. For example, the fine powder metal platinum catalyst described in U.S. Patent No. 2,970,150, the chloroplatinic acid catalyst described in U.S. Patent No. 2,823,218, the complex compound of platinum and hydrocarbon described in the specifications of U.S. Patent No. 3,159,601 and U.S. Patent No. 159,662, the complex compound of chloroplatinic acid and olefin described in U.S. Patent No. 3,516,946, and the complex compound of platinum and vinylsiloxane described in U.S. Patent No. 3,775,452 and U.S. Patent No. 3,814,780 can be mentioned.

[0041] More specifically, simple platinum (platinum black), chloroplatinic acid, platinum-olefin complex, platinum-alcohol complex, or those in which a platinum carrier is supported on a carrier such as alumina or silica can be mentioned.

[0042] The composition of the present invention can contain one or more of the above-mentioned catalysts (Z). The content of the platinum-based catalyst (Z) in the composition of the present invention is usually 0.1 to 100,000 ppm by weight, preferably 0.1 to 10,000 ppm by weight, more preferably 1 to 5,000 ppm by weight, and still more preferably 5 to 1,000 ppm by weight. When the platinum-based catalyst (Z) is used at a ratio within the above range, a composition capable of forming a foam with an appropriate crosslinking density and excellent strength and elongation characteristics can be obtained.

[0043] <Component (BA)> In the present invention, at least one component (BA) selected from aliphatic monocarboxylic acids and metal hydroxide compounds is used as a foaming agent. By using the component (BA) as a foaming agent, a foam excellent in surface smoothness and thus slidability can be obtained. This effect is presumably based on the precipitation of the component (BA) such as stearic acid on the surface of the foam.

[0044] As the aliphatic monocarboxylic acid, a saturated aliphatic monocarboxylic acid is preferable, a saturated aliphatic monocarboxylic acid having 2 to 30 carbon atoms is more preferable, and stearic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, nonadecanoic acid, arachidic acid, 2-ethylhexanoic acid and the like are still more preferable, and stearic acid is particularly preferable.

[0045] The metal hydroxide compound is a compound having a metal atom and a hydroxy group bonded to the metal atom, and examples thereof include aluminum hydroxide and magnesium hydroxide. In one embodiment of the present invention, in the presence of the platinum-based catalyst (Z), the carboxy group or hydroxy group contained in the component (BA) reacts with the hydrogen bonded to the Si atom such as the hydrogen in the side chain contained in the hydrosilyl group-containing compound (Y), and dehydrogenation occurs, and it is considered that the hydrogen functions as a gas as a foaming component.

[0046] Among the components (BA), saturated aliphatic monocarboxylic acids are preferred, and stearic acid is particularly preferred. Regarding the stearic acid, in the prior art, it is known that stearic acid acts as a processing aid, but it is not known to use stearic acid as a foaming agent in the hydrosilylation crosslinking system of ethylene·α-olefin·non-conjugated polyene copolymers.

[0047] The content of the component (BA) in the composition of the present invention is 5 to 30 parts by mass, preferably 10 to 20 parts by mass, more preferably 15 to 20 parts by mass, based on 100 parts by mass of the copolymer (S). Such an embodiment is preferable in terms of obtaining an appropriate foaming and crosslinking rate. When the content of the component (BA) is less than 5 parts by mass, foaming tends not to proceed well, and when it exceeds 30 parts by mass, crosslinking tends not to proceed well.

[0048] By preferably containing the above components within the above ranges, the composition of the present invention can obtain a foam excellent in surface smoothness and thus slidability.

[0049] <Reaction inhibitor (D)> The composition of the present invention preferably further contains a reaction inhibitor (D). The reaction inhibitor (D) is a compound having a function of suppressing the crosslinking reaction (hydrosilylation addition reaction to an alkene) between the alkenyl group of the copolymer (S) and the hydrosilyl group of the hydrosilyl group-containing compound (Y). In the case of a composition using the copolymer (S) and the hydrosilyl group-containing compound (Y), since the hydrosilylation crosslinking reaction has already started from the initial stage of kneading under heating, the processability during kneading may gradually decrease. Blending the reaction inhibitor (D) into the composition is preferable in terms of stabilizing the processability during kneading and molding of the composition.

[0050] Examples of the reaction inhibitor (D) include benzotriazole; acetylene alcohols such as 1 - hexyn - 3 - ol, 3 - methyl - 1 - butyn - 3 - ol, 3,6 - dimethyl - 4 - octyn - 3,6 - diol, 2,4,7,9 - tetramethyl - 5 - decyn - 4,7 - diol, 1 - ethynylcyclohexanol, 3,5 - dimethyl - 1 - hexyn - 3 - ol; acrylonitrile; amide compounds such as N,N - diallylacetamide, N,N - diallylbenzamide, N,N,N',N' - tetraallyl - o - phthalic diamide, N,N,N',N' - tetraallyl - m - phthalic diamide, N,N,N',N' - tetraallyl - p - phthalic diamide; and other organic peroxides such as sulfur, phosphorus, nitrogen, amine compounds, sulfur compounds, phosphorus compounds, tin, tin compounds, tetramethyltetravinylcyclotetrasiloxane. Among these, 3,5 - dimethyl - 1 - hexyn - 3 - ol is preferred.

[0051] The composition of the present invention can contain one or more reaction inhibitors (D). The content of the reaction inhibitor (D) in the composition of the present invention is usually 0.05 to 5 parts by mass, preferably 0.07 to 5 parts by mass, more preferably 0.07 to 4.5 parts by mass, still more preferably 0.1 to 4.5 parts by mass, 0.1 to 3.0 parts by mass, or 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the copolymer (S). Such an embodiment is preferable in terms of obtaining an appropriate cross - linking rate.

[0052] <Reinforcing agent> The composition of the present invention preferably further contains one or more reinforcing agents. The reinforcing agent is a known rubber reinforcing agent compounded in the rubber composition, and examples thereof include carbon black, carbon black surface - treated with a silane coupling agent, silica, calcium carbonate, activated calcium carbonate, fine powder talc, and fine powder silicic acid. The content of the reinforcing agent in the composition of the present invention is preferably 70 to 200 parts by mass, more preferably 70 to 150 parts by mass with respect to 100 parts by mass of the copolymer (S).

[0053] <Softening agent> The composition of the present invention preferably further contains one or more softeners. The softener is a known softener blended in a rubber composition, for example, petroleum-based softeners such as process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, petrolatum, etc.; coal tar-based softeners such as coal tar; fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, coconut oil, etc.; waxes such as beeswax, carnauba wax, etc.; naphthenic acid, pine oil, rosin or its derivatives; synthetic polymer substances such as terpene resin, petroleum resin, coumarone-indene resin, etc.; ester-based softeners such as dioctyl phthalate, dioctyl adipate, etc.; and others such as microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricating oil, tall oil, and factice. Among these, petroleum-based softeners are preferred, and process oil is more preferred.

[0054] The content of the softener in the composition of the present invention is preferably 40 to 100 parts by mass, more preferably 40 to 90 parts by mass, based on 100 parts by mass of the copolymer (S).

[0055] <Other components> In addition to the above components, the composition of the present invention can appropriately contain rubber compounding agents, such as organic peroxides, metal salts of α,β-unsaturated organic acids, anti-aging agents, crosslinking aids, crosslinking accelerators, fillers, defoaming agents, processing aids, activators, antioxidants, plasticizers, tackifiers, etc., as long as the object of the present invention is not impaired.

[0056] In addition, the composition of the present invention can contain rubbers and resins other than the copolymer (S) as other components. Examples of the rubber include silicone rubber, ethylene-propylene random copolymer rubber (EPR), natural rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber, and chloroprene rubber. Examples of the resin include general-purpose resins such as polyethylene, polypropylene, and polystyrene.

[0057] [Processing method of the composition] When the composition of the present invention is at a relatively low temperature of 50 to 130 ° C during kneading and molding processes, the crosslinking reaction is suppressed. Therefore, it is excellent in moldability such as extrusion moldability, press moldability, injection moldability, etc., and processability such as roll processability. Moreover, at the crosslinking temperature of 150 to 300 ° C, it is also excellent in the crosslinking property of being able to crosslink in a short time.

[0058] In order to obtain a foam using the composition of the present invention, a known general processing method (molding method) of rubber compounds can be adopted. Specifically, it is as follows, but it is not limited to the following conditions.

[0059] Using internal mixers such as Banbury mixers, kneaders, and intermixers, for example, copolymer (S), component (BA), and optionally other components (e.g., reinforcing agents, softening agents, defoaming agents) are kneaded at a temperature of 80 to 170 ° C for 3 to 10 minutes, and then a hydrosilyl group-containing compound (Y), a platinum-based catalyst (Z), and optionally other compounding agents (e.g., reaction inhibitor (D)) or other rubbers and resins are added, and kneaded at a roll temperature of 50 to 130 ° C for 5 to 30 minutes using rolls such as open rolls or a kneader, and then separated to prepare. In this way, a ribbon-like or sheet-like composition is usually obtained.

[0060] The obtained composition can be preformed into a desired shape by various molding methods such as an extrusion molding machine, calender rolls, a press, an injection molding machine, a transfer molding machine, etc., or introduced into a vulcanizing tank simultaneously with or during molding and heated to crosslink to obtain a foam.

[0061] As the heating method, known methods can be used without limitation. In particular, it is preferable to use a heating tank in a heating form such as hot air, glass bead fluidized bed, UHF (extremely high frequency electromagnetic wave), steam, LCM (hot molten salt bath), etc., and heat at a temperature of 150 to 300 ° C for 1 to 30 minutes. When molding and crosslinking, a mold may or may not be used. When not using a mold, the rubber composition is usually continuously molded, crosslinked, and foamed.

[0062] The foam obtained from the composition of the present invention can be used for various applications. Specifically, for example, it can be suitably used in applications such as highly foamed sealing materials, sealing materials for automobiles, sealing materials for civil engineering and construction, and various industrial sealing materials. It is particularly suitable for weatherstrip sponge materials (the foaming ratio is preferably 1.3 to 4.0 times), and also, for example, highly foamed sponge materials (the foaming ratio is preferably more than 3.0 times and 30 times or less) used for sponges, dam rubbers, etc.

[0063] Specific examples of the foam include sponge materials for weatherstrips such as sponges for door sponges, sponges for opening trims, sponges for hood seals, sponges for trunk seals, etc.; highly foamed sponge materials such as heat insulating sponges and dam rubbers.

Examples

[0064] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts" means "parts by mass".

[0065] [Production Example 1] Production of ethylene·α-olefin·non-conjugated polyene copolymer Using a continuous polymerization apparatus, an ethylene - propylene - 5 - vinyl - 2 - norbornene (VNB) copolymer (S - 1) was produced as follows.

[0066] Into a polymerization reactor with a volume of 300 liters, a dehydrated and purified hexane solvent was continuously supplied at 58.3 L / hr from line 1, triisobutylaluminum (TiBA) at 4.5 mmol / hr from line 2, (C6H5)3CB(C6F5)4 at 0.150 mmol / hr, and di(p-tolyl)methylene(cyclopentadienyl)(octamethyl octahydrodibenzofluorenyl)zirconium dichloride at 0.030 mmol / hr. At the same time, ethylene was continuously supplied into the polymerization reactor at 6.6 kg / hr, propylene at 9.3 kg / hr, hydrogen at 18 liters / hr, and VNB at 340 g / hr from separate lines respectively, and copolymerization was carried out under the conditions of a polymerization temperature of 87 °C, a total pressure of 1.6 MPaG, and a residence time of 1.0 hour.

[0067] The solution of the ethylene·propylene·VNB copolymer produced in the polymerization reactor was continuously discharged at a flow rate of 88.0 liters / hr and heated to a temperature of 170 °C (the pressure increased to 4.1 MPaG) and supplied to a phase separator. At this time, ethanol, which is a polymerization inhibitor, was continuously introduced into the discharge line in an amount 0.1 mol times that of TiBA in the liquid component withdrawn from the polymerization reactor.

[0068] In the phase separator, the solution of the ethylene·propylene·VNB copolymer was separated into a concentrated phase (lower phase part) containing most of the ethylene·propylene·VNB copolymer and a dilute phase (upper phase part) containing a small amount of polymer.

[0069] The separated concentrated phase was led to a heat exchanger K at 85.4 liters / hr and further led into a hopper, where the solvent was evaporated and separated, and an ethylene·propylene·VNB copolymer was obtained in an amount of 7.8 kg / hr.

[0070] The physical properties of the obtained copolymer (S-1) were measured by the method described above. The Mooney viscosity ML of the copolymer (S-1) (1+4)125 °C was 69, the molar ratio (ethylene unit / propylene unit) was 70 / 30, the content ratio of the VNB unit was 1.4% by mass, and the intrinsic viscosity [η] measured in decalin at 135 °C was 2.8 dL / g. The molecular weight distribution of the obtained copolymer (S-1) showed bimodality.

[0071] [Example 1] As the first step, using a BB-4 type Banbury mixer (manufactured by Kobe Steel, Ltd.), 100 parts of the ethylene·propylene·VNB copolymer (S-1) obtained in Production Example 1 was kneaded for 30 seconds, and then to this, 102 parts of carbon black (Asahi #50HG, manufactured by Asahi Carbon Co., Ltd.), 60 parts of heavy calcium carbonate (Whiton SB, manufactured by Shiraishi Calcium Co., Ltd.), 52 parts of paraffinic process oil (Diana Process Oil PS-430, manufactured by Idemitsu Kosan Co., Ltd.), 5 parts of specially treated calcium oxide (Vesta PP, manufactured by Inoue Lime Industry Co., Ltd.), and 5 parts of stearic acid (powdered stearic acid Sakura, manufactured by NOF Corporation) were added, and kneaded at 140 °C for 2 minutes. Then, the ram was raised for cleaning, and further kneaded for 1 minute, and discharged at about 150 °C to obtain Compound A.

[0072] Next, as the second step, Compound A was wound around an 8-inch roll (manufactured by Nippon Roll Co., Ltd., the surface temperature of the front roll was 50 °C, the surface temperature of the rear roll was 50 °C, the rotational speed of the front roll was 16 rpm, and the rotational speed of the rear roll was 18 rpm), and to this, 4 parts of a hydrosilyl group-containing compound (manufactured by Shin-Etsu Chemical Co., Ltd.: X-93-1346, (CH3)3SiO-(SiH(CH3)-O-)6-Si(CH3)2-O-Si(C6H5)2-O-Si(CH3)3), 0.2 parts of a platinum-based catalyst (manufactured by Shin-Etsu Chemical Co., Ltd.: X-93-1410, chloroplatinic acid + [CH2=CH(Me)SiO]4 complex), and 0.72 parts of a reaction inhibitor (manufactured by Shin-Etsu Chemical Co., Ltd.: X-93-1036, 3,5-dimethyl-1-hexyne-3-ol) were added and kneaded for 10 minutes to obtain an uncrosslinked composition.

[0073] Next, the uncrosslinked composition was extruded and formed into a sheet using a 50 mmφ extruder (manufactured by Mitsuba Seisakusho Co., Ltd.; L / D = 16) equipped with a sheet die (width 25 mm, thickness 2 mm) under the conditions of a die temperature of 80°C, a cylinder temperature of 60°C, and a screw temperature of 50°C. This formed body was crosslinked in a HAV (hot air vulcanization tank) with an atmosphere of 230°C for 5 minutes to obtain a sheet-like foam.

[0074] [Example 2] It was carried out in the same manner as in Example 1 except that the compounding composition was changed as described in Table 1. [Evaluation] <Specific gravity> The specific gravity of the foam was measured according to the water displacement method (JIS K6268).

[0075] <Vulcanization rate> Using MDR2000 (manufactured by Alpha Technologies), the vulcanization curve was measured, and from the vulcanization curve, the minimum value S'min [dNm] and the maximum value S'max [dNm] of the torque, with the minimum value S'min of the torque being 0% and the maximum value S'max being 100%, the time [min]: tc10 when the torque of the measurement sample reached 10%, the time [min]: tc20 when the torque of the measurement sample reached 20%, the time [min]: tc90 when the torque of the measurement sample reached 90%, and the difference between the minimum value S'min [dNm] and the maximum value S'max [dNm]: S'max - S'min [dNm] were determined. The measurement conditions were a temperature of 150°C and a time of 20 minutes. The smaller this tc90, the faster the vulcanization rate.

[0076] <Slip property> The surface of the obtained foam was rubbed with a finger and subjected to a sensory evaluation according to the following criteria. 1: Smooth 2: Feeling resistance when rubbed 3: Feeling stronger resistance than 2 4: Not slippery when rubbed

[0077]

Table 1

Claims

1. It has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene (C) containing two or more of at least one partial structure selected from the formulas (I) and (II) in total in the molecule, and an ethylene-α-olefin-non-conjugated polyene copolymer (S) that satisfies the following requirements (i) and (ii), A hydrosilyl group-containing compound (Y) having at least two hydrosilyl groups in one molecule, A platinum-based catalyst (Z) for hydrosilylation crosslinking, A composition for forming a foam, which contains 5 to 30 parts by mass of a component (BA) that is stearic acid with respect to 100 parts by mass of the copolymer (S), and the Mooney viscosity ML of the copolymer (S) at 125 °C （１＋４） is a foam obtained by crosslinking a foam-forming composition having a value of 69 to 95, and the specific gravity of the foam is 0.78 to 1.

16. 【Chemical 1】 (i) The molar ratio (structural unit derived from ethylene (A) / structural unit derived from α-olefin (B) having 3 to 20 carbon atoms) is 40 / 60 to 99.9 / 0.

1. (ii) The content ratio of the structural unit derived from the non-conjugated polyene (C) is 0.07 to 10% by mass in 100% by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (S).

2. The foam according to claim 1, wherein the expansion ratio of the foam is 1.3 to 4.0 times.

3. It has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene (C) containing two or more of at least one partial structure selected from the formulas (I) and (II) in total in the molecule, and an ethylene-α-olefin-non-conjugated polyene copolymer (S) that satisfies the following requirements (i) and (ii), A hydrosilyl group-containing compound (Y) having at least two hydrosilyl groups in one molecule, A platinum-based catalyst (Z) for hydrosilylation crosslinking, It contains at least one component (BA) selected from aliphatic monocarboxylic acids and metal hydroxide compounds in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of the copolymer (S), The Mooney viscosity ML of the copolymer (S) at 125 °C （１＋４） is 69 to 95, A step of molding a molded body using the composition for forming a foam, wherein the component (BA) is stearic acid, A step of heating and crosslinking the molded body at a temperature of 150 to 300 ° C. for 1 to 30 minutes using a heating bath to obtain a foam, and A method for forming a foam, wherein the specific gravity of the foam is 0.78 to 1.

16. 【Chemical 2】 (i) The molar ratio (structural unit derived from ethylene (A) / structural unit derived from α-olefin (B) having 3 to 20 carbon atoms) is 40 / 60 to 99.9 / 0.

1. (ii) The content ratio of the structural unit derived from the non-conjugated polyene (C) is 0.07 to 10% by mass in 100% by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (S).

4. The method for forming a foam according to claim 3, wherein the expansion ratio of the foam is 1.3 to 4.0 times.

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