JP4949680B2 - Cross-linkable foamable rubber composition and cross-linked foam comprising the composition - Google Patents

Description

  The present invention relates to a rubber composition capable of being crosslinked and foamed, and a seal sponge, cushion sponge, heat insulating sponge, protective sponge, flame retardant sponge and foam roll obtained therefrom. Specifically, it is a rubber composition capable of crosslinking and foaming, which has a high crosslinking speed and excellent productivity, and can be continuously crosslinked such as HAV (hot air vulcanization tank) and UHF (microwave vulcanization tank). The various sponges obtained are lightweight, compression set, strength properties, heat resistance, weather resistance, bloom resistance, stain resistance, scratch resistance, volatilization resistance, odor resistance and foamed rubber surface The present invention relates to various sponges having excellent properties such as smoothness.

  Ethylene / α-olefin / non-conjugated polyene random copolymer rubbers such as EPDM are generally excellent in weather resistance, heat resistance, and ozone resistance, and are used in seal sponges, cushion sponges, and protects for automobiles, home appliances, buildings, etc. Widely used in sponges, heat insulating sponges, flame retardant sponges, etc.

  Automobiles, home appliances, and buildings are products that combine various parts into products, but protect sponges to protect parts, heat-insulating sponges to insulate, cushion sponges to protect against impact, and each sponge has flame resistance. When applying, a flame retardant sponge is used. For example, when combining parts, there will always be more or less gaps. In order to seal this gap, a sponge-like sealing material is used. In this case, the sealing material is easy to incorporate, and since it is necessary to be deformed in accordance with the gap, it is required to be soft, and a sealing sponge is used as a sealing material that can meet such a requirement.

  However, such a sponge does not have sufficient compression set resistance by sulfur vulcanization conventionally employed in the production thereof, and cannot be sealed from sound, dust, water, etc. over a long period of time. Further, in sulfur vulcanization, it is known that nitrosamine generated during molding adversely affects the human body because a vulcanization accelerator is used for EPDM having a low vulcanization rate. In addition, since these accelerators are poorly compatible with EPDM, they often bloom on the sponge surface after molding, impairing the appearance, or contaminating the mating material on contact.

  The weather strip sponge, the main product of automotive seal sponges, also uses EPDM, but the conventional sulfur vulcanization does not have sufficient compression set resistance, and noise, dust, Can't seal rainwater. Further, in sulfur vulcanization, an accelerator having a large vulcanization acceleration effect is used for EPDM having a low vulcanization speed, so that nitrosamine generated during molding has a disadvantage of adversely affecting the human body. In addition, since these accelerators have poor compatibility with EPDM, they have the disadvantages of blooming or bleeding on the surface of the sponge product after molding to impair the appearance or contaminate the sheet metal after mounting.

  As a method for solving this drawback, a method of converting from sulfur vulcanization to peroxide (organic peroxide) crosslinking having good compression set resistance and low pollution property is effective. In the case of continuous crosslinking such as (hot air vulcanization tank) and UHF (microwave vulcanization tank), there is a disadvantage that the rubber surface does not crosslink or causes degradation (degradation) and the scratch resistance is extremely inferior. This is because radicals generated from organic peroxides pull out tertiary carbon hydrogen from polymer chains, and polymer radicals generated in tertiary carbon react with oxygen in the air, causing molecular chain scission. However, if the cross-linking is performed by steam cross-linking or lead cross-linking for the purpose of blocking oxygen, the scratch resistance of the rubber surface is improved, but it is disadvantageous in terms of production cost.

  JP-A-4-154855 (Patent Document 1) discloses an ethylene / propylene / diene copolymer rubber that can be hot-air crosslinked with HAV and an organo group having at least two hydrogen atoms bonded to silicon atoms in one molecule. It is described that by using a rubber composition in which hydrogen polysiloxane and a platinum catalyst are blended, hot-air crosslinking is possible and a rubber having excellent scratch resistance can be obtained. The inventors of the present application have further tried the invention described in this publication, and as a result, the scratch resistance and the compression set resistance have not been sufficiently satisfied.

  Japanese Patent Laid-Open No. 7-33924 (Patent Document 2) discloses a peroxide composition obtained by adding a polysiloxane having at least one reactive group to an ethylene / propylene / diene copolymer rubber. By doing so, it is described that a hot-air crosslinking is possible and a rubber having excellent scratch resistance can be obtained. However, the inventors of the present application have further tried the invention described in this publication, and as a result, although the crosslinking efficiency is increased by adding peroxide to the rubber composition, the peroxide radical is siloxane. It is confirmed that the scratch resistance of the surface of the rubber product after crosslinking is not practical enough to cause the addition reaction of the polymer and the generation of polymer radicals.

  In addition, the inventors of the present application provide a specific ethylene / α-olefin / non-conjugated polyene random copolymer rubber (A), a SiH group-containing compound (B) having at least two SiH groups in one molecule, and a necessity. Accordingly, by using a rubber composition comprising a catalyst (C), a reaction inhibitor (D), and a foaming agent (E), it can be crosslinked by hot air crosslinking (HAV, UHF, etc.) excellent in production cost, and it is resistant to compression. Although it has been found that a foam excellent in distortion and scratch resistance can be produced (Japanese Patent Laid-Open No. 2001-31789) (Patent Document 3), further improvement in compression set resistance is desired.

  The inventors of the present application have conducted intensive research on an ethylene / α-olefin / non-conjugated polyene random copolymer rubber composition, and obtained one molecule of ethylene / α-olefin / non-conjugated polyene random copolymer rubber (A) and SiH groups. A rubber composition containing at least two SiH group-containing compounds (B), a catalyst (C), a foaming agent (D), and optionally a reaction inhibitor (E) has a high crosslinking rate. Excellent productivity, can be crosslinked by hot air crosslinking (HAV, UHF, etc.), and has high foaming ratio, that is, light weight, compression set resistance, strength characteristics, heat resistance, weather resistance, bloom resistance, stain resistance and Although it has been found that a foam having excellent scratch resistance can be produced (Japanese Patent Application Laid-Open No. 2002-371152) (Patent Document 4), it is desired to improve the smoothness of the rubber surface after foaming.

Accordingly, the inventors of the present application have made extensive studies on an organic polymer rubber composition containing a vinyl group, an organic polymer containing a vinyl group (A), and an SiH group containing at least two SiH groups in one molecule. It contains compound (B), catalyst (C), baking soda (D), and foam nucleating agent (E), and the weight percent of the foaming nucleating agent (E) in the foaming nucleating agent (E) and baking soda (D) is 20%. A rubber composition of ˜80% by weight has a high crosslinking rate and excellent productivity, and can be crosslinked by hot air crosslinking (HAV, UHF, etc.), and has a high foaming ratio, that is, light weight, compression set resistance and strength characteristics. The present inventors have found that a foam having excellent heat resistance, weather resistance, bloom resistance, stain resistance, scratch resistance, volatilization resistance, odor resistance and smoothness of the rubber surface after foaming can be produced.
Japanese Laid-Open Patent Publication No. 154855 Japanese Patent Laid-Open No. 33924 Japanese Patent Laid-Open No. 31789 JP 2002371115 A

  The present invention relates to a rubber composition capable of being crosslinked and foamed, and a seal sponge, cushion sponge, heat insulating sponge, protective sponge, flame retardant sponge and foam roll obtained therefrom. Specifically, it is to provide a crosslinkable foamable rubber composition having a high crosslinking speed and excellent productivity and capable of continuous crosslinking such as HAV (hot air vulcanization tank) and UHF (microwave vulcanization tank). In addition, the various sponges obtained therefrom are lightweight, compression set, strength properties, heat resistance, weather resistance, bloom resistance, stain resistance, scratch resistance, volatilization resistance, odor resistance and foaming. An object of the present invention is to provide the various sponges having excellent properties such as the smoothness of the later rubber surface.

The crosslinked foamable rubber composition of the present invention is provided by adding a combination of baking soda having a specific average particle size and particle size distribution and a blowing agent having a specific average particle size and particle size distribution. Specifically, it is provided by the matters described in the following [1] to [ 10 ].

[1] An ethylene / propylene / non-conjugated polyene random copolymer rubber- containing organic polymer (A) containing a vinyl group, a SiH group-containing compound (B) having at least two SiH groups in one molecule, A rubber composition comprising a platinum-based catalyst (C), baking soda (D), and a foaming nucleating agent (E) that is citric acid , and the foaming nuclei in the foaming nucleating agent (E) and baking soda (D) Ri wt% 20 to 80 wt% der the agent (E),
The non-conjugated polyene is 5-vinyl-2-norbornene;
The 1-4th quantile, which is an index of the particle size distribution of sodium bicarbonate (D), is 0.1-20 μm, the 3-4th quantile is 2-40 μm, and the particle size distribution (3-4 quantile / 1− The 4th quantile) is 2 to 10, the 1-4th quantile is 0.1 to 20 μm, and the 3rd to 4th quantile is 2 which is an index of the particle size distribution of the foam nucleating agent (E). A rubber composition capable of crosslinking and foaming, characterized by having a particle size distribution (3-4 quantile / 1-4 quantile) of 2 to 10 and ˜40 μm .

  [2] The crosslinked foamable rubber composition according to [1], wherein the average particle size of the baking soda (D) is 1 to 25 μm.

[3] The crosslinkable foamable rubber composition of [1] or [2], wherein the foam nucleating agent (E) has an average particle size of 1 to 25 μm .

[4] The organic polymer (A) containing a vinyl group has (1) a molar ratio of ethylene to propylene (ethylene / propylene) in the range of 50/50 to 90/10, and (2) an iodine value. [1] to [3], wherein the intrinsic viscosity [η] measured with a decalin solution at 135 ° C. is in the range of 0.1 to 5 dl / g. A rubber composition capable of being crosslinked and foamed.

[5] A seal sponge obtained from the rubber composition capable of crosslinking and foaming according to any one of [1] to [4].

[6] A cushion sponge obtained from the rubber composition capable of crosslinking and foaming according to any one of [1] to [4].

[7] A heat insulating sponge obtained from the crosslinkable foamable rubber composition according to any one of [1] to [4].

[8] A protective sponge obtained from the crosslinkable foamable rubber composition according to any one of [1] to [4].

[9] A flame retardant sponge obtained from the crosslinkable foamable rubber composition according to any one of [1] to [4].

[10] A foam roll obtained from the crosslinkable foamable rubber composition according to any one of [1] to [4].

  The rubber composition capable of crosslinking and foaming according to the present invention has a high crosslinking rate, is excellent in the productivity of crosslinked foam, can be hot-air crosslinked such as HAV and UHF, and has a high foaming ratio, that is, light weight, and is resistant to resistance. Various above-mentioned properties such as compression set, strength properties, heat resistance, weather resistance, bloom resistance, stain resistance, scratch resistance, volatilization resistance, odor resistance and smoothness of rubber surface after foaming A sponge can be provided.

  The rubber composition capable of being crosslinked and foamed according to the present invention and the seal sponge, cushion sponge, heat insulating sponge, protective sponge, flame retardant sponge, and foam roll obtained therefrom will be specifically described.

  The rubber composition capable of crosslinking and foaming according to the present invention comprises an organic polymer (A) containing a vinyl group, a SiH group-containing compound (B), a catalyst (C), a baking soda (D), and a foam nucleating agent (E). Contains.

[Organic polymer containing vinyl group (A)]
The organic polymer containing a vinyl group used in the present invention (A) is Ri organic polymer der containing at least one vinyl group in the molecule, ethylene-propylene-non-conjugated polyene random copolymer rubber There is . The non-conjugated polyene is 5-vinyl-2-norbornene.

As the organic polymer (A) containing a vinyl group, specifically,
1) Polyether-based polymers such as polyoxyethylene, polyoxypropylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer;
2) Condensates of dibasic acids such as terephthalic acid, isophthalic acid and adipic acid or their anhydrides with glycols such as ethylene glycol, propylene glycol and neopentyl glycol;
3) a polyester copolymer obtained by ring-opening polymerization of lactones;
4) Ethylene / α-olefin / non-conjugated polyene random copolymer containing vinyl group, ethylene / α-olefin random copolymer rubber, polyisobutylene, copolymer of isobutylene and isopropylene, polychloroprene, poly Isoprene, copolymers of isoprene and butadiene, acrylonitrile or styrene, polybutadiene, copolymers of butadiene and styrene or acrylonitrile, and copolymers of polyisoprene, polybutadiene, isoprene, butadiene and acrylonitrile, styrene, etc. Hydrocarbon polymers such as copolymers obtained by hydrogenation of
5) Acrylic ester-based polyacrylates obtained by radical polymerization of monomers such as ethyl acrylate and butyl acrylate, acrylic esters such as ethyl acrylate and butyl acrylate, and vinyl acetate, acrylonitrile, methyl methacrylate, styrene, etc. Coalescence;
6) A graft polymer obtained by polymerizing a vinyl monomer in the organic polymer;
7) Polysulfide polymer; and 8) Polycarbonate polymer produced by condensation polymerization of bisphenol A and carbonyl chloride.

  Of these, polyester polymers, polyether polymers, acrylate polymers, and hydrocarbon polymers 4) above are preferred. Among the hydrocarbon polymers, ethylene / α-olefin / non-conjugated polyene random copolymer containing vinyl group, ethylene / α-olefin random copolymer rubber, and polyisobutylene are particularly preferable.

  The iodine value of the organic polymer (A) containing a vinyl group is preferably 1 to 30 (g / 100 g), more preferably 3 to 20 (g / 100 g), particularly preferably 5 to 15 (g / 100 g), Most preferably, it is 10-15 (g / 100g).

  The intrinsic viscosity [η] measured in 135 ° C. decalin of the organic polymer (A) containing a vinyl group is 0.1 to 5 dl / g, and preferably 1 to 4.5 dl / g when used as a millable rubber. Particularly preferably, it is preferably 1 to 3.5 dl / g. When used as a liquid rubber, it is preferably 0.1 to 0.5 dl / g, particularly preferably 0.1 to 0.3 dl / g.

[Ethylene / α-olefin / non-conjugated polyene random copolymer rubber]
The organic polymer (A) containing a vinyl group used in the present invention, preferably a hydrocarbon polymer containing a vinyl group. Among them, particularly preferred is an ethylene / α-olefin / non-conjugated polyene. Random copolymer rubber.

  It is a random copolymer of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene.

  Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1- Examples include dodecene and 12-ethyl-1-tetradecene. Among these, α-olefins having 3 to 10 carbon atoms are preferable, and propylene, 1-butene, 1-hexene, 1-octene and the like are particularly preferably used. These α-olefins are used alone or in combination of two or more.

  The non-conjugated polyene used in the present invention is a terminal vinyl group-containing norbornene compound represented by the following general formula [I] or [II].

［式中、ｎは０ないし１０の整数であり、Ｒ^１は水素原子または炭素原子数１〜１０のアルキル基であり、Ｒ^２は水素原子または炭素原子数１〜５のアルキル基である］

[Wherein n is an integer of 0 to 10, R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms]

［式中、Ｒ^３は水素原子または炭素原子数１〜１０のアルキル基である］
一般式［Ｉ］において、Ｒ^１の炭素原子数１〜１０のアルキル基を具体的に示すと、メチル基、エチル基、プロピル基、イソプロピル基、Ｎ−ブチル基、イソブチル基、Ｓｅｃ−ブチル基、ｔ−ブチル基、Ｎ−ペンチル基、イソペンチル基、ｔ−ペンチル基、ネオペンチル基、ヘキシル基、イソヘキシル基、へプチル基、オクチル基、ノニル基、デシル基などが挙げられる。また、Ｒ^２については、水素原子または上記のペンチル基までの炭素原子数１〜５のアルキル基が具体例である。

[Wherein R ³ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms]
In the general formula [I], when the alkyl group having 1 to 10 carbon atoms of R ¹ is specifically shown, methyl group, ethyl group, propyl group, isopropyl group, N-butyl group, isobutyl group, Sec-butyl group , T-butyl group, N-pentyl group, isopentyl group, t-pentyl group, neopentyl group, hexyl group, isohexyl group, heptyl group, octyl group, nonyl group, decyl group and the like. As for R ² is an alkyl group having 1 to 5 carbon atoms up hydrogen atom or the above-pentyl group is a specific example.

In the general formula [II], specific examples of the alkyl group represented by R ³ include the same alkyl groups as the specific examples of the alkyl group represented by R ¹ .

  Specific examples of the norbornene compound represented by the general formula [I] or [II] include 5-methylene-2-norbornene, 5-vinyl-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-hexyl) -2-norbornene, 5- (5-ethyl-5-hexenyl) -2-norbornene, 5- (1 , 2,3-trimethyl-4-pentenyl) -2-norbornene and the like. Among these, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (3-butenyl) -2-norbornene, 5- (4-pentenyl) ) -2-norbornene, 5- (5-hexenyl) -2-norbornene, 5- (6-heptenyl) -2-norbornene and 5- (7-octenyl) -2-norbornene are preferred. These norbornene compounds can be used alone or in combination of two or more.

  In addition to the norbornene compound, for example, 5-vinyl-2-norbornene, the following non-conjugated polyene can be used in combination as long as the target physical properties of the present invention are not impaired. Specific examples of such a non-conjugated polyene include 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, Chain non-conjugated dienes such as 4,5-dimethyl-1,4-hexadiene and 7-methyl-1,6-octadiene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5 -Cyclic non-conjugated dienes such as isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, dicyclopentadiene; 2,3-diisopropylidene-5 Norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, etc. Ene and the like.

  The ethylene / α-olefin / non-conjugated polyene random copolymer rubber composed of various components as described above preferably has the following characteristics.

  (1) The molar ratio of ethylene to α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is 50/50 to 90/10, preferably 55/45 to 80/20, more preferably 60. / 40 to 78/22, particularly preferably 60/40 to 70/30. When this molar ratio is within the above range, a rubber composition capable of providing a crosslinked foam having excellent heat aging resistance, strength characteristics and rubber elasticity, and excellent cold resistance and processability can be obtained.

  (2) The iodine value of the ethylene / α-olefin / non-conjugated polyene random copolymer rubber is 1 to 30 (g / 100 g), preferably 1 to 20 (g / 100 g), more preferably 2 to 10 (g). / 100 g), particularly preferably 3 to 7 (g / 100 g). When used as a millable rubber, it is preferably 1 to 20 (g / 100 g), more preferably 2 to 10 (g / 100 g), and particularly preferably 3 to 7 (g / 100 g). When used as a liquid rubber, it is preferably 3 to 30 (g / 100 g), more preferably 5 to 25 (g / 100 g), and particularly preferably 8 to 15 (g / 100 g). When this iodine value is within the above range, a rubber composition having high crosslinking efficiency is obtained, and a crosslinked foamed molded article having excellent compression set resistance and environmental degradation resistance (= heat aging resistance) is provided. A rubber composition that can be obtained is obtained. An iodine value exceeding 30 is not preferable because it is disadvantageous in terms of environmental degradation resistance and cost.

  (3) Intrinsic viscosity [η] measured in a 135 ° C. decalin solution of ethylene / α-olefin / non-conjugated polyene random copolymer rubber is 0.1 to 5 dl / g, preferably when used as a millable rubber It is preferably 1 to 4.5 dl / g, particularly preferably 1 to 3.5 dl / g. When used as a liquid rubber, it is preferably 0.1 to 0.5 dl / g, particularly preferably 0.1 to 0.3 dl / g. When the intrinsic viscosity [η] is within the above range, a rubber composition that can provide a crosslinked foam having excellent strength characteristics and compression set resistance and excellent workability can be obtained.

  (4) The branching index of the ethylene / α-olefin / non-conjugated polyene random copolymer rubber (A) determined by a dynamic viscoelasticity measuring device is 1 to 30, preferably 2 to 20, particularly preferably 3 to 10. It is. When this branching index is within the above range, a rubber composition capable of providing a crosslinked foamed molded article excellent in processability, shape retention after extrusion molding and thixotropy can be obtained.

  The ethylene / α-olefin / non-conjugated polyene random copolymer rubber (A) used in the present invention is a polymer production process (Industrial Research Committee Co., Ltd., published p. 309-330) or the applicant's application. JP-A-9-71617, JP-A-9-71618, JP-A-9-208615, JP-A-10-67823, JP-A-10-67824, JP-A-10-110054, etc. It can be prepared by a conventionally known method as described.

  Examples of the olefin polymerization catalyst used in the production of the ethylene / α-olefin / non-conjugated polyene random copolymer rubber used in the present invention include transitions such as vanadium (V), zirconium (Zr), and titanium (Ti). A Ziegler catalyst comprising a metal compound and an organoaluminum compound (organoaluminum oxy compound), or a metallocene compound of a transition metal selected from Group IVB of the periodic table of elements, and an organoaluminum oxy compound or an ionized ionic compound A metallocene catalyst is particularly preferably used.

Further, when an ethylene / α-olefin / non-conjugated polyene random copolymer rubber is prepared using a catalyst containing the following compounds (H) and (I) as main components, the boiling xylene insoluble content is 1% or less. An ethylene / α-olefin / non-conjugated polyene random copolymer rubber is preferable because it is obtained. That is, the ethylene / α-olefin / non-conjugated polyene random copolymer rubber having a xylene-insoluble content of 1% or less is polymerized in the presence of a catalyst containing the following compounds (H) and (I) as main components. 30 to 60 ° C., particularly 30 to 59 ° C., polymerization pressure 4 to 12 kgf / cm ² , particularly 5 to 8 kgf / cm ² , molar ratio of the supply amount of non-conjugated polyene and ethylene (non-conjugated polyene / ethylene) 0.01 By randomly copolymerizing ethylene, an α-olefin having 3 to 20 carbon atoms, and a terminal vinyl group-containing norbornene compound represented by the above general formula [I] or [II] under the condition of ~ 0.2 can get. The copolymerization is preferably carried out in a hydrocarbon medium.

(H) a soluble vanadium compound represented by VO (OR) _N X _3-N (wherein R is a hydrocarbon group, X is a halogen atom, and N is an integer of 0 or 1 to 3), Or a vanadium compound represented by VX ₄ (X is a halogen atom).

  The soluble vanadium compound is a component that is soluble in the hydrocarbon medium of the polymerization reaction system. Specifically, the general formula VO (OR) aXb or V (OR) cXd (wherein R is a hydrocarbon group, 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3 ≦ c + d ≦ 4), or their electron donor adducts Can be cited as a representative example.

More specifically, VOCl ₃ , VO (OC ₂ H ₅ ) Cl ₂ , VO (OC ₂ H ₅ ) ₂ Cl, VO (O-iSo—C ₃ H ₇ ) Cl ₂ , VO (O—N—C ₄ H ₉ ) Cl ₂ , VO (OC ₂ H ₅ ) ₃ , VOBr ₃ , VCl ₄ , VOCl ₃ , VO (O—N—C ₄ H ₉ ) ₃ , VCl ₃ · 2OC ₆ H ₁₂ OH, etc. be able to.

(I) An organoaluminum compound represented by R ′ _N AlX ′ _3-N (R ′ is a hydrocarbon group, X ′ is a halogen atom, and m is 1 to 3).

Specific examples of the organoaluminum compound (I) include trialkylaluminum such as triethylaluminum, tributylaluminum, and triisopropylaluminum; dialkylaluminum alkoxide such as diethylaluminum ethoxide and dibutylaluminum butoxide; ethylaluminum sesquiethoxide, Alkylaluminum sesquialkoxides such as butylaluminum sesquibutoxide; partially alkoxylated alkylaluminums having an average composition represented by R ¹ _0.5 Al (OR ¹ ) _0.5, etc .; diethylaluminum chloride, dibutylaluminum chloride, Dialkylaluminum halides such as diethylaluminum bromide; ethylaluminum sesquichloride, butylaluminum Alkyl aluminum sesquihalides such as skichloride, ethylaluminum sesquibromide, partially halogenated alkylaluminums such as alkylaluminum dihalides such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide; diethylaluminum hydride, dibutylaluminum hydride Partially hydrogenated alkylaluminums such as alkylaluminum dihydrides such as dialkylaluminum hydride, ethylaluminum dihydride, propylaluminum dihydride, etc .; moieties such as ethylaluminum ethoxychloride, butylaluminum butoxycyclide, ethylaluminum ethoxybromide Alkoxylated and halogenated alkylal Or the like can be mentioned chloride.

In the present invention, among the above compound (H), a soluble vanadium compound represented by VOCl ₃ and among the above compound (I), Al (OC ₂ H ₅ ) ₂ Cl / Al ₂ (OC ₂ H ₅ ) ₃ Cl _When the blended product with No. ₃ (blend ratio is 1/5 or more) is used as a catalyst component, the insoluble content after Soxhlet extraction (solvent: boiling xylene, extraction time: 3 hours, mesh: 325) is 1% or less. Ethylene / α-olefin / non-conjugated polyene random copolymer rubber (A) is preferable because it is obtained.

  Further, as the catalyst used in the copolymerization, a so-called metallocene catalyst such as a metallocene catalyst described in JP-A-9-40586 may be used.

  The organic polymer (A) containing a vinyl group used in the present invention may be graft-modified with a polar monomer such as an unsaturated carboxylic acid or a derivative thereof (such as an acid anhydride or ester).

  Specific examples of such unsaturated carboxylic acids include carboxylic acids represented by acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Representative examples of unsaturated carboxylic acid anhydrides include maleic anhydride and itaconic anhydride. Among these, maleic anhydride is preferable.

  The above-mentioned graft modifiers (graft monomers) such as unsaturated carboxylic acids are used singly or in combination of two or more, and in any case, 100 g of the organic polymer containing the vinyl group before graft modification described above. The amount of the graft is preferably 0.1 mol or less. When ethylene / α-olefin / non-conjugated polyene random copolymer rubber having a graft amount within the above range is used, it is possible to provide a crosslinked foamed molded article excellent in cold resistance. An excellent rubber composition can be obtained.

  The organic polymer (A) containing a graft-modified vinyl group is obtained by reacting the aforementioned polymer containing an unmodified vinyl group with an unsaturated carboxylic acid or a derivative thereof in the presence of a radical initiator. be able to. This grafting reaction can be performed as a solution or in a molten state. When the graft reaction is performed in a molten state, it is most efficient and preferable to perform it continuously in an extruder.

  Specific examples of the radical initiator used in the graft reaction include dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, and t-butyl. Cumyl peroxide, di-t-amyl peroxide, t-butyl hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxin) hexyne-3, 2,5-dimethyl-2,5 Dialkyl peroxy such as di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, α, α'-bis (t-butylperoxy-m-isopropyl) benzene Oxides; t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxy Peroxyesters such as maleic acid, t-butylperoxyneodecanoate, t-butylperoxybenzoate, di-t-butylperoxyphthalate; ketone peroxides such as dicyclohexanone peroxide; and mixtures thereof Etc. Among them, organic peroxides having a half-life of 1 minute in the range of 130 to 200 ° C. are preferable, and in particular, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3. Organic peroxides such as 1,5-trimethylcyclohexane, t-butylcumyl peroxide, di-t-amyl peroxide, and t-butyl hydroperoxide are preferred.

  In addition, as polar monomers other than unsaturated carboxylic acids or derivatives thereof (for example, acid anhydrides and esters), a hydroxyl group-containing ethylenically unsaturated compound, an amino group-containing ethylenically unsaturated compound, an epoxy group-containing ethylenically unsaturated compound, Aromatic vinyl compounds, vinyl ester compounds, vinyl chloride and the like can be mentioned.

[SiH group-containing compound (B)]
The SiH group-containing compound (B) used in the present invention reacts with the organic polymer (A) containing a vinyl group and acts as a crosslinking agent. The molecular structure of the SiH group-containing compound (B) is not particularly limited, and it can be used for conventionally produced resinous materials such as linear, cyclic, branched structures, or three-dimensional network structures. It is necessary that one molecule contains at least 2, preferably 3 or more hydrogen atoms directly bonded to silicon atoms, that is, SiH groups.

As such a SiH group-containing compound (B), a compound represented by the following general composition formula R ⁴ _b H _c SiO _{(4-bc) / 2} can be usually used. In the above general composition formula, R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, excluding an aliphatic unsaturated bond. Examples of the valent hydrocarbon group include a phenyl group and a halogen-substituted alkyl group such as a trifluoropropyl group, in addition to the alkyl group exemplified for R ¹ in the general formula [I]. Of these, a methyl group, an ethyl group, a propyl group, a phenyl group, and a trifluoropropyl group are preferable, and a methyl group and a phenyl group are particularly preferable.

Further, b is 0 ≦ b <3, preferably 0.6 <b <2.2, particularly preferably 1.5 ≦ b ≦ 2, and c is 0 <c ≦ 3, preferably 0.002. ≦ c <2, particularly preferably 0.01 ≦ c ≦ 1, and b + c is 0 <b + c ≦ 3, preferably 1.5 <b + c ≦ 2.7. This SiH group-containing compound (B) is an organohydrogenpolysiloxane having preferably 2 to 1000, particularly preferably 2 to 300, and most preferably 4 to 200 silicon atoms in one molecule. Specifically, siloxane oligomers such as 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyltetracyclosiloxane, 1,3,5,7,8-pentamethylpentacyclosiloxane, etc. -; Trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both molecular chain ends, Trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both chain ends, Silanol group-blocked methylhydrogenpolysiloxane at both molecular chain ends, Molecular chain Both end silanol-blocked dimethylsiloxane and methylhydrogensiloxane Polymer, both ends dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane Copolymer, consisting of R ⁴ ₂ (H) SiO _1/2 units and SiO _4/2 units, optionally R ⁴ ₃ SiO _1/2 units, R ⁴ ₂ SiO _2/2 units, R ⁴ (H) Mention may be made, for example, of silicone resins which may contain SiO _2/2 units, (H) SiO _3/2 or R ⁴ SiO _3/2 units.

  Examples of the methyl hydrogen polysiloxane blocked with a trimethylsiloxy group at both ends of the molecular chain include, for example, a compound represented by the following formula, and further, in the following formula, a part or all of the methyl group is an ethyl group, propyl group, phenyl group, trifluoropropyl group. And the like.

(CH ₃ ) ₃ SiO — (— SiH (CH ₃ ) —O—) _d —Si (CH ₃ ) ₃ [wherein d is an integer of 2 or more. ]
As the dimethylsiloxane / methylhydrogensiloxane copolymer blocked with trimethylsiloxy group at both ends of the molecular chain, a compound represented by the following formula, and further, in the following formula, part or all of the methyl group is ethyl group, propyl group, phenyl group, Examples include compounds substituted with a trifluoropropyl group and the like.

_{(CH 3) 3 SiO - (} - Si (CH 3) 2 -O-) e - (- SiH (CH 3) -O-) f -Si (CH 3) 3 [e in the formula is an integer of 1 or more And f is an integer of 2 or more. ]
Examples of the methyl hydrogen polysiloxane blocked with silanol groups at both ends of the molecular chain include, for example, a compound represented by the following formula, and a part or all of the methyl group in the following formula: ethyl group, propyl group, phenyl group, trifluoropropyl group, etc. And the like.

_{HOSi (CH 3) 2 O -} (- SiH (CH 3) -O-) 2 -Si (CH 3) 2 OH
Examples of the dimethylsiloxane / methylhydrogensiloxane copolymer blocked with silanol groups at both ends of the molecular chain include, for example, a compound represented by the following formula, and further a part or all of the methyl group in the following formula: an ethyl group, a propyl group, a phenyl group, Examples include compounds substituted with a trifluoropropyl group and the like.

_{HOSi (CH 3) 2 O -} (- Si (CH 3) 2 -O-) e - (- SiH (CH 3) -O-) f --Si (CH 3) 2 OH [e in the formula 1 It is the above integer, and f is an integer of 2 or more. ]
Examples of the dimethylpolysiloxane blocked with dimethylhydrogensiloxy group at both ends of the molecular chain include, for example, a compound represented by the following formula, and further, in the following formula, a part or all of the methyl group is an ethyl group, a propyl group, a phenyl group, a trifluoropropyl group. And the like.

_{HSi (CH 3) 2 O -} (- Si (CH 3) 2 -O-) e -Si (CH 3) is 2 H [e in the formula is an integer of 1 or more. ]
Examples of the methyl hydrogen polysiloxane blocked with dimethylhydrogensiloxy group blocked at both ends of the molecular chain include, for example, a compound represented by the following formula, and further a part or all of the methyl group in the following formula: ethyl group, propyl group, phenyl group, trifluoro Examples thereof include compounds substituted with a propyl group or the like.

_{HSi (CH 3) 2 O -} (- SiH (CH 3) -O-) e -Si (CH 3) is 2 H [e in the formula is an integer of 1 or more. ]
Examples of the dimethylhydrogensiloxy group-blocked dimethyl siloxane / methyl hydrogen siloxane copolymer having both ends of the molecular chain include, for example, a compound represented by the following formula, and further a part or all of the methyl group in the following formula: ethyl group, propyl group, And compounds substituted with a phenyl group, a trifluoropropyl group, and the like.

_{HSi (CH 3) 2 O -} (- Si (CH 3) 2 -O-) e - (- SiH (CH 3) -O-) h --Si (CH 3) 2 H [e in the formula, and h Are each an integer of 1 or more. ]
Among these, molecular chain both ends trimethylsiloxy group-capped methylhydrogenpolysiloxane and molecular chain both ends dimethylhydrogensiloxy group-capped methylhydrogenpolysiloxane are preferable. As molecular hydrogen both ends trimethylsiloxy group blocked methyl hydrogen polysiloxane,
_{(CH 3) 3 SiO - [} - SiH (CH 3) -O-] 6 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] 1 - _{Si (CH 3) 3, (} CH 3) 3 SiO - [- SiH (CH 3) -O-] 5 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) _{2 -O-] 1 -Si (CH 3} ) 3, (CH 3) 3 SiO - [- SiH (CH 3) -O-] 4 - [- Si (CH 3) 2 -O-] 1 - [- _{Si (C 6 H 6) 2} -O-] 1 -Si (CH 3) 3, (CH 3) 3 SiO - [- SiH (CH 3) -O-] 3 - [- Si (CH 3) 2 - _{O-] 1 - [- Si (} C 6 H 6) 2 -O-] 1 -Si (CH 3) 3, (CH 3) 3 SiO - [- SiH (CH 3) -O-] 2 - [- Si (CH ₃ ) ₂ —O—] _{1 - [- Si (C 6 H} 6) 2 -O-] 1 -Si (CH 3) 3, (CH 3) 3 SiO - [- SiH (CH 3) -O-] 6 - [- Si (C 6 _{H 6) 2 -O-] 1 -Si} (CH 3) 3, (CH 3) 3 SiO - [- SiH (CH 3) -O-] 5 - [- Si (C 6 H 6) 2 -O- _{] 1 -Si (CH 3) 3} , (CH 3) 3 SiO - [- SiH (CH 3) -O-] 4 [-Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) _3, (CH ₃ ) ₃ SiO — [— SiH (CH ₃ ) —O—] ₃ —Si (C ₆ H ₆ ) ₂ —O—] ₁ —Si (CH ₃ ) _3, (CH ₃ ) ₃ SiO— _{[-SiH (CH 3) -O-]} 2 - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 3 is preferred.

The molecular chain both ends endcapped with dimethyl hydrogen siloxy group _{methylhydrogenpolysiloxane, HSi (CH 3) 2 O} - [- SiH (CH 3) -O-] 6 - [- Si (CH 3) 2 -O- ] ₁ -[— Si (C ₆ H ₆ ) ₂ —O—] ₁ —Si (CH ₃ ) ₂ H _, HSi (CH ₃ ) ₂ O — [— SiH (CH ₃ ) —O—] ₅ — [— _{Si (CH 3) 2 -O-]} 1 - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 2 H, HSi (CH 3) 2 O - [- SiH (CH 3 _{) -O-] 4 - [- Si} (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 2 H, HSi (CH 3) _{2 O - [- SiH (CH} 3) -O-] 3 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] _{-Si (CH 3) 2 H,} HSi (CH 3) 2 O - [- SiH (CH 3) -O-] 2 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 _{H 6) 2 -O-] 1 -Si} (CH 3) 2 H, HSi (CH 3) 2 O - [- SiH (CH 3) -O-] 6 - [- Si (C 6 H 6) 2 - _{O-] 1 -Si (CH 3)} 2 H, HSi (CH 3) 2 O - [- SiH (CH 3) -O-] 5 - [- Si (C 6 H 6) 2 -O-] 1 - _{Si (CH 3) 3, HSi} (CH 3) 2 O - [- SiH (CH 3) -O-] 4 [-Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 2 H _{, HSi (CH 3) 2 O} - [- SiH (CH 3) -O-] 3 -Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 2 H, HSi (CH 3) 2 O- [ _{SiH (CH 3) -O-] 2} - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 2 H, C 6 H 5 -Si (OSi (CH 3) 2 H) ₃ is preferred.

  Such a compound can be produced by a known method, for example, octamethylcyclotetrasiloxane and / or tetramethylcyclotetrasiloxane, and hexamethyldisiloxane or 1,3-dihydro-1,1 which can be a terminal group. And a compound containing a triorganosilyl group or a diorganohydrogensiloxy group, such as 1,3,3-tetramethyldisiloxane, at −10 ° C. in the presence of a catalyst such as sulfuric acid, trifluoromethanesulfonic acid or methanesulfonic acid. It can be easily obtained by equilibrating at a temperature of about ~ 40 ° C.

  The SiH group-containing compound (B) is 0.1 to 100 parts by weight, preferably 0.1 to 75 parts by weight, and more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the organic polymer (A) containing a vinyl group. 1-50 parts by weight, more preferably 0.2-30 parts by weight, still more preferably 0.2-20 parts by weight, particularly preferably 0.5-10 parts by weight, most preferably 0.5-5 parts by weight It is used in the ratio. When the SiH group-containing compound (B) is used in a proportion within the above range, a rubber composition capable of forming a crosslinked foam having excellent resistance to compression set, moderate crosslinking density and excellent strength and elongation properties is obtained. It is done. Use of the SiH group-containing compound (B) in a proportion exceeding 100 parts by weight is not preferable because it is disadvantageous in terms of cost.

  Further, the ratio of SiH groups to aliphatic unsaturated groups involved in the crosslinking of the organic polymer (A) containing vinyl groups (SiH group / aliphatic unsaturated group) is 0.2 to 20, more preferably 0.00. It is preferably 5 to 10, particularly 0.7 to 5.

[Catalyst (C)]
The catalyst (C) used in the present invention is an addition reaction catalyst, and an addition reaction between the alkenyl group of the organic polymer (A) component containing the vinyl group and the SiH group of the SiH group-containing compound (B) ( This promotes the hydrosilylation reaction of alkenes.

  Usually, for example, an addition reaction catalyst comprising a platinum group element such as a platinum-based catalyst, a palladium-based catalyst, or a rhodium-based catalyst is used. In the present invention, a group 8 element metal, a vinyl group and / or a carbonyl group in the periodic table It is desirable to use a complex with a compound containing As the group 8 element metal of the periodic table, platinum is particularly preferable.

  As the compound containing a carbonyl group, carbonyl, octanal and the like are preferable. Specific examples of the complex of these with platinum include a platinum-carbonyl complex, a platinum-octanal complex, a platinum-carbonylbutyl cyclic siloxane complex, and a platinum-carbonylphenyl cyclic siloxane complex. As the compound containing a vinyl group, a vinyl group-containing organosiloxane is preferable. Specific examples of complexes of these with platinum include platinum-divinyltetramethyldisiloxane complex, platinum-divinyltetraethyldisiloxane complex, platinum-divinyltetrapropyldisiloxane complex, platinum-divinyltetrabutyldisiloxane complex, platinum -Divinyltetraphenyldisiloxane complex.

  Among the vinyl group-containing organosiloxanes, vinyl group-containing cyclic organosiloxanes are preferable. Examples of the complex of platinum with platinum include a platinum-vinylmethyl cyclic siloxane complex, a platinum-vinylethyl cyclic siloxane complex, and a platinum-vinylpropyl cyclic siloxane complex. The vinyl group-containing organosiloxane itself may be a ligand for a metal, but may be used as a solvent for coordinating other ligands. A complex in which a vinyl group-containing organosiloxane is used as a solvent and the above-mentioned compound containing a carbonyl group is a ligand is particularly preferable as the catalyst (C) of the present invention.

  Specific examples of such complexes include a platinum-carbonyl complex vinylmethyl cyclic siloxane solution, a platinum-carbonyl complex vinylethyl cyclic siloxane solution, a platinum-carbonyl complex vinylpropyl cyclic siloxane solution, and a platinum-carbonyl complex divinyl. Tetramethyldisiloxane solution, platinum-carbonyl complex divinyltetraethyldisiloxane solution, platinum-carbonyl complex divinyltetrapropyldisiloxane solution, platinum-carbonyl complex divinyltetrabutyldisiloxane solution, platinum-carbonyl complex divinyltetraphenyldi A siloxane solution is mentioned.

  The catalyst comprising these complexes may further contain components other than the compound containing a vinyl group and / or a carbonyl group. For example, a solvent other than a compound containing a vinyl group and / or a carbonyl group may be contained. Examples of these solvents include various alcohols and xylene, but are not limited thereto.

  Specific examples of the alcohol include aliphatics such as methanol, ethanol, propanol, and isopropyl alcohol, such as undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and eicosyl alcohol. Saturated alcohols; aliphatic unsaturated alcohols such as allyl alcohol and crotyl alcohol; alicyclic alcohols such as cyclopentanol and cyclohexanol; aromatic alcohols such as benzyl alcohol and cinnamyl alcohol; furfuryl alcohol and the like And heterocyclic alcohols.

  An example of using alcohol as a solvent is a platinum-octanal / octanol complex. By including these solvents, there are advantages such as easy handling of the catalyst and easy mixing with the rubber composition. Among the various catalysts mentioned above, a platinum-carbonyl complex vinylmethyl cyclic siloxane solution (a complex represented by the following chemical formula 1 is preferred), a platinum-vinylmethyl cyclic siloxane complex (a complex represented by the chemical formula 2 is particularly preferred). ), Platinum-divinyltetramethyldisiloxane complexes (preferably the complex represented by Chemical Formula 3), platinum-octanal / octanol complexes and the like are practically preferred, and among them, platinum-carbonylvinylmethyl cyclic siloxane complexes are particularly preferred. .

Chemical formula 1: Pt ⁰ · CO · (CH ₂ ═CH (Me) SiO) ₄
Chemical formula 2: Pt ⁰ · (CH ₂ ═CH (Me) SiO) ₄
Chemical formula 3: Pt ⁰ -1.5 [(CH ₂ = CH (Me) ₂ Si) ₂ O]
The ratio of Group 8 element metal (preferably platinum) contained in these catalysts is usually 0.1 to 10% by weight, preferably 1 to 5% by weight, more preferably 2 to 4% by weight, particularly preferably. Is 2.5 to 3.5% by weight.

  The catalyst (C) is 0.1 to 100,000 ppm by weight, preferably 0.1 to 10,000 ppm by weight, more preferably 1 to 5, based on the organic polymer (A) containing a vinyl group. 000 ppm by weight, particularly preferably 5 to 1,000 ppm by weight. When the catalyst (C) is used in a proportion within the above range, a rubber composition capable of forming a crosslinked foamed molded article having excellent scorch resistance and excellent strength characteristics and elongation characteristics can be obtained. Use of the catalyst (C) in a proportion exceeding 100,000 ppm by weight is not preferable because it is disadvantageous in terms of cost.

[Baking soda (D)]
As the baking soda (D) used in the present invention, a conventionally known baking soda or one obtained by treating a conventionally known baking soda is preferably used.

  As the baking soda (D), an average particle diameter of 1 to 25 μm is preferably used. When the average particle diameter of the baking soda (D) is less than 1 μm, it is difficult to disperse in the organic polymer (A) containing a vinyl group, and foreign matter defects are likely to occur. In addition, when the average particle size of baking soda (D) is more than 25 μm, the foamed cell diameter becomes large. As a result, the smoothness of the rubber surface after foaming deteriorates, and only products with poor appearance and low evaluation value are obtained. It is not preferable because it is not possible.

  As the particle size distribution of the baking soda (D), the 1-4th quantiles (described in Saburo Taguchi, Yoshinori Shima, Statistics, 7, Yachiyo Publishing Co., Ltd. (1990)) are 0.1-20 μm, 3- It is preferable that the quartile is 2 to 40 μm and the particle size distribution (3-4 quartile / 1-4 quartile) is 2 to 10. When the 1-4th quantile of baking soda (D) is less than 0.1 μm, it is difficult to disperse in the organic polymer (A) containing a vinyl group, resulting in foreign matters. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, in the OA foam roll, if there is a foreign substance, the charged state becomes uneven, which is a fatal problem that uniform printing cannot be performed. On the other hand, when the 1-4th quantile of baking soda (D) is more than 25 μm, the foamed cell diameter becomes large. As a result, the smoothness of the rubber surface after foaming deteriorates. This is not preferable because the sealing performance against rainwater and noise is poor.

  Moreover, when the 3-4 quantile of baking soda (D) is less than 2 micrometers, it will be difficult to disperse | distribute to the organic polymer (A) containing a vinyl group, and will become a foreign material. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, when the 3-4 quantile of baking soda (D) is more than 40 μm, the foamed cell diameter becomes large. As a result, the smoothness of the rubber surface after foaming deteriorates. This is not preferable because the sealing performance against rainwater and noise is poor. Further, the OA foam roll is not preferable because the toner cannot be uniformly charged, which is a fatal problem.

  A baking soda (D) having a particle size distribution (3-4 quartile / 1-4 quartile) of less than 2 is not preferred because it is difficult to produce and costs are disadvantageous. Moreover, it is hard to disperse | distribute to the organic polymer (A) containing a vinyl group, and becomes a foreign material. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, in the OA foam roll, if there is a foreign substance, the charged state becomes uneven, which is a fatal problem that uniform printing cannot be performed. On the other hand, those having a particle size distribution of more than 10 are not preferable because the foamed cells are non-uniform, and in particular, the sealability for automobiles cannot satisfy the design, and the sealing performance against rainwater and noise is inferior. In the foam roll for OA, the toner cannot be uniformly charged, which is a fatal problem.

  Sodium bicarbonate (D) is 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the organic polymer (A) containing a vinyl group. More preferably, it is used in a ratio of 2 to 10 parts by weight, particularly preferably 3 to 7 parts by weight. When the solid rubber is slightly foamed, it is used in a proportion of 0.1 to 3 parts by weight, preferably 0.2 to 2 parts by weight, and most preferably 0.5 to 1.5 parts by weight. When baking soda (D) is used in a proportion within the above range, a crosslinked foam having excellent design properties and compression set resistance on the foamed rubber surface, moderate crosslinking density, and excellent strength and elongation properties is formed. A rubber composition that can be obtained is obtained.

[Foaming nucleating agent (E)]
Examples of the foam nucleating agent (E) used in the present invention include calcium carbonate, clay, talc, silica, magnesium oxide, zinc oxide, carbon black, silicon dioxide, titanium oxide, plastic microspheres, orthoboric acid, and alkaline earth of fatty acids. Metal salts, citric acid and the like. In the present invention, citric acid is used .

  As the foam nucleating agent (E), an average particle size of 1 to 25 μm is preferably used. If the average particle diameter of the foam nucleating agent (E) is less than 1 μm, it is difficult to disperse in the organic polymer (A) containing a vinyl group, and foreign matter defects are likely to occur. Further, if the average particle diameter of the foam nucleating agent (E) is more than 25 μm, the foam cell diameter becomes large. As a result, the smoothness of the rubber surface after foaming deteriorates, and only a poor-looking product can be obtained. It is not preferable.

  The particle size distribution of the foam nucleating agent (E) is that the 1-4th quantile is 0.1-20 μm, the 3-4 quantile is 2-40 μm, and the particle size distribution (3-4 minutes). It is preferable that the order / quantity (1-4 quartile) is 2-10. When the 1-4th quantile of the foam nucleating agent (E) is less than 0.1 μm, it is difficult to disperse in the organic polymer (A) containing a vinyl group, resulting in foreign matters. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, in the OA foam roll, if there is a foreign substance, the charged state becomes uneven, which is a fatal problem that uniform printing cannot be performed.

  When the 1-4th quantile of the foam nucleating agent (E) is more than 25 μm, the foamed cell diameter becomes large. In particular, the seal sponge for automobiles cannot satisfy the design, and the sealability of rainwater and noise is inferior. Therefore, it is not preferable. In the foam roll for OA, the toner cannot be uniformly charged, which is a fatal problem.

  If the 3-4th quantile of the foam nucleating agent (E) is less than 2 μm, it is difficult to disperse in the organic polymer (A) containing a vinyl group, resulting in foreign matters. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, in the OA foam roll, if there is a foreign substance, the charged state becomes uneven, which is a fatal problem that uniform printing cannot be performed. This is not preferable because foreign matter defects are likely to occur. In addition, if the 3-4th quantile of the foam nucleating agent (E) is more than 40 μm, the foam cell diameter becomes large, resulting in poor smoothness of the rubber surface after foaming. However, it is not preferable because the design property cannot be satisfied and the sealing property of rainwater and noise is inferior. Further, the OA foam roll is not preferable because the toner cannot be uniformly charged, which is a fatal problem.

  A foam nucleating agent (E) having a particle size distribution (3-4 quartile / 1-4 quartile) of less than 2 is not preferable because it is difficult to produce and costs are disadvantageous. Moreover, it is hard to disperse | distribute to the organic polymer (A) containing a vinyl group, and becomes a foreign material. In particular, the seal sponge for automobiles is not preferable because the design property is impaired and the commercial value is lowered. Further, in the OA foam roll, if there is a foreign substance, the charged state becomes uneven, which is a fatal problem that uniform printing cannot be performed.

  When the particle size distribution is more than 10, foamed cells are not uniform, and in particular, an automotive seal sponge cannot satisfy the design, and is inferior in rainwater and noise sealability. In foaming for OA, the toner cannot be uniformly charged, which is a fatal problem.

  These foam nucleating agents (E) are usually 0.1 parts by weight or more and less than 40 parts by weight, preferably 0.2 to 25 parts by weight with respect to 100 parts by weight of the organic polymer (A) containing a vinyl group. More preferably 0.5 to 10 parts by weight, particularly preferably 1 to 5 parts by weight. When the foam nucleating agent (E) is used in a proportion within the above range, a fine foam cell diameter can be obtained, and the rubber surface after foaming is excellent in design and compression set resistance, and has a moderate crosslinking density. A rubber composition capable of forming a crosslinked foam having excellent strength characteristics and elongation characteristics is obtained.

  The concentration of the foam nucleating agent (E) is characterized in that the weight percent of the foam nucleating agent (E) in the baking soda (D) and the foaming nucleating agent (E) is 20 to 80% by weight. The range is preferably 20 to 60% by weight, more preferably 30 to 50% by weight. When the concentration of the foam nucleating agent (E) is less than 20% by weight, a sponge having a uniform cell diameter cannot be obtained. For example, in a foam roll for OA, uniform printing that can uniformly charge the toner is possible. It is not preferable because there is a risk of being unable to do so. On the other hand, if it exceeds 80% by weight, it becomes difficult to foam and it becomes difficult to control foamability, so that practical production becomes difficult, which is not preferable.

  It is preferable to blend sodium bicarbonate (D) and the foam nucleating agent (E) in advance. As such products, Nippon Boehringer Ingelheim Co., Ltd. Hydrocerol CF, Hydrocerol BIT, Hydrocerol BIF, Eiwa Kasei Kogyo Co., Ltd. Cellbon FE-507, Cellbon SC-P, Cellbon SC- K etc. are mentioned.

[Other ingredients]
The crosslinkable foamable rubber composition according to the present invention can be used even in an uncrosslinked state, but can exhibit its characteristics most when used as a crosslinked foam. In the cross-linkable foamable rubber composition according to the present invention, conventionally known reaction inhibitors, rubber reinforcing agents, inorganic fillers, softeners, anti-aging agents, processing aids, depending on the intended use of the cross-linked product. Additives such as vulcanization accelerators, organic peroxides, crosslinking aids, colorants, dispersants, flame retardants and the like can be blended within a range that does not impair the object of the present invention. As these additives, those which do not easily cause chemical behavior of Lewis base are preferably used.

  The reaction inhibitor is used as an optional component together with the catalyst (C), and specifically includes benzotriazole, ethynyl group-containing alcohol (for example, 1-ethynyl-1-cyclohexanol, etc.), acrylonitrile, amide compound (for example, N, N -Diallylacetamide, N, N-diallylbenzamide, N, N, N ', N'-tetraallyl-o-phthalic acid diamide, N, N, N', N'-tetraallyl-m-phthalic acid diamide, N, N , N ′, N′-tetraallyl-p-phthalic acid diamide, etc.), sulfur, phosphorus, nitrogen, amine compounds, sulfur compounds, phosphorus compounds, tin, tin compounds, tetramethyltetravinylcyclotetrasiloxane, hydroperoxide, etc. An organic peroxide etc. are mentioned. Among them, an ethynyl group-containing alcohol such as 1-ethynyl-1-cyclohexanol is particularly preferable.

  A substance having a chemical behavior of Lewis base can also be preferably used. The reaction inhibitor is 0 to 50 parts by weight, usually 0.0001 to 50 parts by weight, preferably 0.001 to 10 parts by weight, more preferably 100 parts by weight of the organic polymer (A) containing a vinyl group. Is used in a proportion of 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, particularly preferably 0.05 to 0.5 parts by weight.

  When the reaction inhibitor (F) is used at a ratio of 50 parts by weight or less, a rubber composition having a high crosslinking speed and excellent productivity of the crosslinked foam can be obtained. When the reaction inhibitor (F) is used in a proportion exceeding 50 parts by weight, the crosslinking rate becomes slow, the balance with the foaming rate is lost, and a good foamed product cannot be made. Further, it is not preferable because it is disadvantageous in terms of cost.

  The rubber reinforcing agent has an effect of enhancing mechanical properties such as tensile strength, tear strength, and wear resistance of the crosslinked rubber. Specific examples of such rubber reinforcing agents include carbons such as SRF, GPF, FEF, HAF, ISAF, SAF, FT, and MT, and those carbons that have been surface-treated with a silane coupling agent. Examples thereof include black, finely divided silicic acid, and silica.

Specific examples of silica include fumed silica and precipitated silica. These silicas may be surface-treated with a reactive silane such as hexamethyldisilazane, chlorosilane, or alkoxysilane, or a low molecular weight siloxane. The specific surface area of silica (BED method) is preferably ^{50 m} 2 / g or more, more preferably 100 to 400 m ² / g.

  The type and blending amount of these rubber reinforcing agents can be appropriately selected depending on the use, but the blending amount of the rubber reinforcing agent is usually 300 weights at maximum with respect to 100 parts by weight of the organic polymer (A) containing a vinyl group. Parts, preferably up to 200 parts by weight. Specific examples of the inorganic filler include light calcium carbonate, heavy calcium carbonate, talc, and clay.

  Although the kind and compounding quantity of these inorganic fillers can be suitably selected according to the use, the compounding quantity of the inorganic filler is usually 5 to 100 parts by weight of the organic polymer (A) containing a vinyl group. 300 parts by weight, preferably 5 to 200 parts by weight. As the softener, a softener usually used for rubber can be used.

  Specifically, petroleum-based softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petroleum jelly; coal-tar softeners such as coal tar and coal tar pitch; castor oil, linseed oil, rapeseed oil, Fat oil-based softeners such as coconut oil; tall oil; sub; waxes such as beeswax, carnauba wax and lanolin; fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, barium stearate, calcium stearate and zinc laurate; petroleum Examples thereof include synthetic polymer materials such as resins, atactic polypropylene, and coumarone indene resins. Of these, petroleum softeners are preferably used, and process oil is particularly preferably used. The blending amount of these softeners is appropriately selected depending on the use of the crosslinked foamed molded product.

  Examples of the anti-aging agent include amine-based, hindered phenol-based, and sulfur-based anti-aging agents. These anti-aging agents are used within the range not impairing the object of the present invention as described above. .

  As the processing aid, a compound used for processing ordinary rubber can be used. Specific examples include higher fatty acids, salts thereof and esters thereof.

  The anti-aging agent and processing aid are usually used in a proportion of 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the organic polymer (A) containing a vinyl group.

  In the present invention, in addition to the catalyst (C) described above, an organic peroxide may be used to perform both addition crosslinking and radical crosslinking. The organic peroxide is used at a ratio of about 0.1 to 10 parts by weight with respect to 100 parts by weight of the organic polymer (A) containing a vinyl group. As the organic peroxide, a conventionally known organic peroxide that is usually used in crosslinking of rubber can be used.

  When using an organic peroxide, it is preferable to use a crosslinking aid in combination. Specific examples of the crosslinking aid include sulfur; quinone dioxime compounds such as p-quinone dioxime; methacrylate compounds such as polyethylene glycol dimethacrylate; allyl compounds such as diallyl phthalate and triallyl cyanurate; maleimide Compounds such as divinylbenzene. Such a crosslinking aid is used in an amount of 0.5 to 2 mol, preferably about equimolar to 1 mol of the organic peroxide used.

  The crosslinked foamable rubber composition according to the present invention can be blended with other known rubbers within a range not impairing the object of the present invention. Examples of such other rubbers include isoprene-based rubbers such as natural rubber (NR) and isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber. Mention may be made of conjugated diene rubbers such as (CR).

  Furthermore, a conventionally known ethylene / α-olefin copolymer rubber can also be used. For example, an ethylene / propylene random copolymer (EPR) other than the ethylene / α-olefin / non-conjugated polyene random copolymer rubber can be used. An ethylene / α-olefin / polyene copolymer (for example, EPDM) can be used.

[For sponge]
The rubber composition capable of crosslinking and foaming according to the present invention can be used as it is uncrosslinked (unvulcanized), but can exhibit its characteristics most when used as a crosslinked foamed rubber molded article. As the use of the crosslinked foam according to the present invention, a seal sponge, a cushion sponge, a heat insulating sponge, a protect sponge, a flame retardant sponge, a foam roll and the like are preferably mentioned.

  Examples of the seal sponge include an automobile seal sponge, a home appliance seal sponge, and a civil engineering seal sponge. Examples of automotive seal sponges include automotive weather strip sponges, specifically door weather strip sponges, bonnet weather strip sponges, trunk room weather strip sponges, sunroof weather strip sponges, ventilator weather strip sponges, lamp seal sponges, or these. Corner sponge etc. Furthermore, there are door seals, body seals, trunk seals, hood seals, and the like. Specific examples of the seal sponge for civil engineering and construction include a gasket, air tight, joint material, or a seal sponge for a door stop.

  Examples of the cushion sponge include a cushion sponge for automobiles, a cushion sponge for home appliances, and a cushion sponge for civil engineering and construction.

  Examples of the heat insulating sponge include a heat insulating sponge for automobiles, a heat insulating sponge for household appliances, and a heat insulating sponge for civil engineering and construction.

  Examples of the protect sponge include a protect sponge for automobiles, a protect sponge for home appliances, and a protect sponge for civil engineering and construction.

  Examples of the flame retardant sponge include a flame retardant sponge for automobiles, a flame retardant sponge for home appliances, and a flame retardant sponge for civil engineering and construction.

  Examples of the foam roll include a printer transfer roll, a printer development roll, a printer paper feed roll, a copy transfer roll, a copy development roll, a copy paper feed roll, and an industrial roll.

[Preparation of rubber composition and its crosslinked foam]
In order to produce the above various sponges obtained from the crosslinkable foamable rubber composition according to the present invention, an uncrosslinked compounded rubber is prepared once in the same manner as when ordinary rubber is vulcanized (crosslinked) and foamed. Then, the compounded rubber may be formed into an intended shape and then crosslinked and foamed.

  As a crosslinking / foaming method, a crosslinking agent (SiH group-containing compound (B)), a catalyst (C) and baking soda (D), a method of heating using a foaming nucleating agent (E), or light, γ-ray, electron Either of the methods by irradiation with rays may be adopted. First, the crosslinkable foamable rubber composition according to the present invention is prepared, for example, by the following method.

  That is, the crosslinkable foamable rubber composition according to the present invention is obtained by using an organic polymer containing a vinyl group (an internal mixer) such as a Banbury mixer, a kneader, an intermix, or a planetary mixer. A), and if necessary, additives such as rubber reinforcing agents, inorganic fillers, softeners and the like are kneaded at a temperature of 25 to 170 ° C. for 3 to 10 minutes, and then a roll such as an open roll or a kneader is used. Then, an SiH group-containing compound (B), a catalyst (C), a baking soda (D), a foaming nucleating agent (E), and, if necessary, a reaction inhibitor and other components are additionally mixed, and preferably a roll temperature of 80 It can be prepared by kneading at 1 ° C. or lower for 1 to 30 minutes and then dispensing.

  In the present invention, the organic polymer (A) containing a vinyl group, a rubber reinforcing agent, an inorganic filler and the like can be kneaded at a high temperature, but the SiH group-containing compound (B), the catalyst (C), May be cross-linked (scorched) when kneaded at a high temperature at the same time. Therefore, when the SiH group-containing compound (B) and the catalyst (C) are added simultaneously, it is preferable to knead at 80 ° C. or lower. . When one component is added among the SiH group-containing compound (B) and the catalyst (C), they can be kneaded even at a high temperature exceeding 80 ° C. In some cases, it is preferable to use cooling water against heat generated by kneading.

  In addition, when the kneading temperature in the internal mixer is low, the catalyst contains a vinyl group-containing organic polymer (A), SiH group-containing compound (B), rubber reinforcing agent, inorganic filler, softener, etc. (C), baking soda (D), foaming nucleating agent (E), reaction inhibitor, anti-aging agent, colorant, dispersant, flame retardant and the like may be kneaded simultaneously.

  The rubber composition capable of crosslinking and foaming according to the present invention prepared as described above is molded into an intended shape by various molding methods using an extruder or the like, and vulcanized at the same time as molding or the molded product. It can be introduced into the tank and crosslinked / foamed. A crosslinked sponge can be obtained by heating at a temperature of 100 to 270 ° C. for 1 to 60 minutes or by irradiating light, γ-rays or electron beams by the above-described method. In this crosslinking / foaming step, a mold may be used, or crosslinking / foaming may be performed without using a mold. When a mold is not used, the molding, crosslinking and foaming steps are usually carried out continuously. As a heating method in the vulcanization tank, a heating tank such as hot air, UHF (microwave), PCM (glass bead fluidized bed), steam or the like can be used.

  Further, when the organic polymer (A) containing a vinyl group having a low molecular weight is used, since the rubber (A) is in a liquid state, a kneader for liquid rubber such as a planetary mixer or three rolls is used. Then, mix the SiH group-containing compound (B) in a liquid state, mix the catalyst (D), baking soda (D), foaming nucleating agent (E), and, if necessary, the reaction inhibitor, and mold into the intended shape. And can be crosslinked / foamed at room temperature or by heating.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples at all. The composition, iodine value, intrinsic viscosity [η], and branching index of the copolymer rubber used in Examples and Comparative Examples were measured or determined by the following methods.
(1) Polymer composition: Measured by ¹³ C-NMR method.
(2) Iodine value: determined by a titration method.
(3) Intrinsic viscosity [η]; measured in a 135 ° C. decalin solution.

(4) Branching index Long chain branching: Frequency dispersion of complex viscosity η ^* was measured for EPR (4 samples having different molecular weights) having no branching using a dynamic viscoelasticity tester. The complex viscosity η ^* at 0.01 rad / Sec and 8 rad / Sec is obtained, and the complex viscosity η _1L ^* (0.01 rad / Sec) is plotted on the vertical axis, and the complex viscosity η _2L ^* (8 rad / Sec) is plotted on the vertical axis. Plotting on the horizontal axis, creating a reference line, and measuring η _1L0 ^* when η _2L ^* = 1 × 10 ³ / Pa · S on the extension of the line. Next, similarly for the target sample, the complex viscosity η ^* at 0.01 rad / Sec and 8 rad / Sec is obtained, and the complex viscosity η _1B ^* (0.01 rad / Sec) is plotted on the vertical axis. The rate η _2B ^* (8 rad / Sec) is plotted on the horizontal axis. This plot has a larger value than the reference line, and the longer the long chain branch, the larger the distance from the reference line.
Next, the reference line was translated so as to pass over this plot, and the intersection point η _1B0 ^* with the complex viscosity η ₂ ^* = 1 × 10 ³ / Pa · sec was measured. The branching index was calculated by applying the values of η _1L0 ^* and η _1B0 ^* measured as described above to the following equation.
Branch index = (log η _1L0 ^* −log η _1B0 ^* ) × 10
The measurement conditions are as follows.
Reference samples: 4 types of EPR Mitsui Chemicals, Tuffmer P-0280, P-0480, P-0680, P-0880 (trade name)
-Dynamic viscoelasticity tester (RDS): Rheometrics company-Sample: Used by punching a 2 mm sheet into a 25 mm diameter circle.
-Temperature: 190 ° C-Distortion rate: 1%-Frequency dependence: 0.001-500 rad / sec

(5) Oil extended amount: 1 g (W0) of polymer is cut into a cubic shape of about 1 mm × 1 mm × 1 mm and put into a glass filter (G3). 200 ml of methyl ethyl ketone is put into a flask, heated with a heater, and after boiling, a glass filter containing a polymer is put into the flask and extracted for 2 hours. After extraction, the polymer was dried at 105 ° C. for 1 hour, the weight (W1) of the polymer was measured, and the oil spread was measured by the following formula.
Oil extended amount (phr) = (W0−W1) / W1 × 100

(6) Molecular weight distribution Mw / Mn; expressed as a ratio of weight average molecular weight Mw / number average molecular weight Mn determined by GPC. Various average molecular weights were calculated in terms of EPDM conversion values. The measurement conditions are as follows.
Equipment: Waters 150C
Detector: DRI (150C built-in)
Column: Ahodex UT-806MLT (50 cm x 1)
Solvent: 1,2,4-trichlorobenzene Temperature: 135 ° C
Flow rate: 1 ml / min Concentration: 0.2% (w / v)
Injection volume: 160 μl

_{(7) γ 2 / γ 1} ; 100 at ℃ melt flow - Ca - determine the blanking, shear rate gamma ₁ when indicating the 0.4 × ¹⁰ 6 dyn / cm ² and 2.4 × 10 ⁶ dyn / cm ² The ratio of the shear rate γ ₂ was calculated. The L / D of the used orifice is 60 mm / 3 mm.

(8) Effective network chain density ν; In accordance with JIS K 6258 (1993), toluene was immersed in toluene at 37 ° C. for 72 hours, and the effective network chain density ν was calculated from the Flory-Rehner equation and the following equation.
ν (pieces / cm ³ ) = [ν _R + ln (1−ν _R ) + μν _R ² ] / [− V ₀ (ν _R ^1/3 −ν _R / 2)]
ν _R ; pure rubber volume fraction μ relative to pure rubber volume (pure rubber volume + absorbed solvent volume) in swollen vulcanized rubber; rubber-solvent interaction constant (0.49)
V ₀ ; Molecular volume of solvent ν (pieces / cm ³ )
The sample was prepared by adding 0.01 mol of dicumyl peroxide to 100 g of the random copolymer, kneading by the method described in SRIS using 8 inthio-roll at a kneading temperature of 50 ° C. The obtained sample was produced by press vulcanization at 170 ° C. for 10 minutes.

(9) Parameter K (relation between γ ₂ / γ ₁ and effective network chain density ν)
Log (γ ₂ / γ ₁ ) / ν was set as K, and it was obtained by calculation.

"Production Example 1" [Production of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-1)]
A ternary copolymerization of ethylene, propylene and 5-vinyl-2-norbornene was continuously performed using a stainless polymerizer (stirring rotation speed = 250 rpm) having a substantially internal volume of 100 liters equipped with a stirring blade. From the side of the polymerization vessel to the liquid phase, 60 liters of hexane per hour, 3.3 kg of ethylene, 12.0 kg of propylene, 240 g of 5-vinyl-2-norbornene, 20 liters of hydrogen, VOCl ₃ as a catalyst At a rate of 22 mmol, Al (Et) ₂ Cl at 66 mmol, and Al (Et) _1.5 Cl _1.5 at a rate of 66 mmol.

  When the copolymerization reaction was performed under the conditions described above, an ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber was obtained in a uniform solution state. Thereafter, a small amount of methanol was added to the polymerization solution continuously withdrawn from the lower part of the polymerization vessel to stop the polymerization reaction, with respect to 100 parts by weight of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber. After adding 20 parts by weight of paraffin oil [trade name Diana Process Oil PW-380, manufactured by Idemitsu Kosan Co., Ltd.], the polymer is separated from the solvent by steam stripping, and then vacuum dried at 55 ° C. for 48 hours. It was.

  Table 1 shows the physical properties of the ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-1) obtained as described above.

"Production Examples 2-3"
In Production Example 1, by changing the polymerization conditions as shown in Table 1, ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-2), ethylene / propylene / 5-vinyl having different properties A 2-norbornene random copolymer rubber (A-3) was obtained. The physical properties of the two copolymer rubbers obtained are shown in Table 1.

"Baking soda 1-6, citric acid 1-5"
As the baking soda, the product name Serbon FE-507 manufactured by Eiwa Kasei Kogyo Co., Ltd. is used, and the cross jet mill (KJ25) of Kurimoto Works is used, and the amount of air used is 0.5 Nm ³ / min. It processed for 1 minute on condition, and it passed once through 633 mesh. Select 100 particles of baking soda passed through the mesh, measure the particle size (maximum length) with a microscope, average particle size, 1-4th quantile, 3-4 quantile, particle size distribution ( 3-4 quantile / 1-4 quantile) was measured. Citric acid was similarly crushed and classified. The results are shown in Table 2.

"Example 1"
120 parts by weight of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-1) shown in Table 1, carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 60HG] , 70 parts by weight of softener [made by Idemitsu Kosan Co., Ltd., trade name; Diana Process Oil ^TM PS-430], and 5 parts by weight of calcium oxide [trade name Vesta PP, made by Inoue Lime Industry Co., Ltd.] The mixture was kneaded with a 95 liter Banbury mixer [manufactured by Kobe Steel, Ltd.].

  As a kneading method, first, ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber was masticated for 30 seconds, and then carbon black, a softening agent and calcium oxide were added and kneaded for 2 minutes. Thereafter, the ram was raised and cleaned, and further kneaded for 1 minute and discharged at about 130 ° C. to obtain a rubber compound (I-1). This kneading was performed at a filling rate of 75%.

Next, 315 parts by weight of this compound (I-1) was added to an 8-inch roll (front roll surface temperature 50 ° C., rear roll surface temperature 50 ° C., front roll rotation speed 18 rpm, rear roll rotation speed 15 rpm). 6 parts by weight of baking soda 1 shown in Table 2 as a foaming agent, 4 parts by weight of citric acid 1 shown in Table 2 as a foaming nucleating agent, and (CH ₃ ) ₃ SiO— as a SiH group-containing compound (crosslinking agent) _{[-SiH (CH 3) -O-]} 6 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] a ₁ -Si _{(CH 3)} 3 4 parts by weight [manufactured by Shin-Etsu Chemical Co., Ltd.] (in Tables 3 to 10, “SiH group-containing compounds * 1” are all the above compounds), 1-ethynyl-1- as a reaction inhibitor Add 0.2 parts by weight of cyclohexanol and knead for 10 minutes. 0.033 parts by weight of a vinylmethyl cyclic siloxane solution of a platinum carbonyl vinylmethyl complex having a concentration of 3% platinum [GELEST. After adding INc, trade name SIP6829.0] and kneading for 5 minutes, the kneaded product was separated into ribbons. The total amount of the kneaded material was about 2 kg. About the obtained uncrosslinked rubber compound, the scorch time and the crosslinking rate were measured by the following methods.

(A) Scorch time;
The scorch time at 125 ° C. was measured according to JIS K6300-1 (2001).

(B) crosslinking rate;
According to JIS K6300-2 (2001), tc (90) at 180 ° C. was measured.

  Using this uncrosslinked rubber compound, a die temperature of 80 ° C. and a cylinder using a 50 mmφ extruder (manufactured by Mitsuba Corporation; L / D = 16) equipped with a tubular die (inner diameter: 10 mm, wall thickness: 1 mm) Extrusion was performed under the conditions of a temperature of 70 ° C. and a screw temperature of 50 ° C. to form a tube. This molded body was crosslinked with HAV (hot air vulcanization tank) at 230 ° C. for 5 minutes to obtain sponge rubber.

  About the obtained crosslinked sponge rubber, specific gravity measurement, expansion ratio, water absorption measurement, compression stress, tensile test, compression set test, total VOC, odor resistance, product appearance, and presence / absence of foreign matter were measured according to the following methods. .

(A) Specific gravity measurement A 20 mm × 20 mm test piece was punched out from a tubular sponge rubber cross-linked with hot air, and the surface was wiped off with alcohol. Using a specific gravity meter (Made by Toyo Seiki Seisakusho Co., Ltd .: Model M-1) under an atmosphere of 25 ° C., the test piece was measured for specific gravity from the mass difference between air and pure water, and the specific gravity of sponge rubber was determined. Calculated.

(B) Foaming ratio A test piece of 20 mm × 20 mm was punched out from the uncrosslinked rubber compound before foaming, and the surface dirt was wiped off with alcohol. This test piece was measured for specific gravity from the difference in mass between air and pure water using an automatic hydrometer [manufactured by Toyo Seiki Seisakusho: M-1 type] in an atmosphere of 25 ° C., and an uncrosslinked rubber compound The specific gravity of was calculated. The expansion ratio was calculated as follows.
Foaming ratio (times) = specific gravity of uncrosslinked rubber compound / specific gravity of sponge rubber (C) Water absorption rate A test piece of 20 mm × 20 mm is punched out from a tubular sponge rubber cross-linked with hot air, up to 125 mmHg at a position 50 mm below the water surface. Depressurized and held for 3 minutes. Subsequently, the test piece was returned to the atmosphere, and after 3 minutes had elapsed, the weight of the absorbed test piece was measured, and the water absorption rate was calculated from the following formula.
Water absorption (%) = [(W ₂ −W ₁ ) / W ₁ ] × 100
W ₁ : Weight of test specimen before immersion (g).
W ₂ : Test piece weight after immersion (g).

(D) Compressive stress test A hot-air crosslinked tube-like sponge is cut to 30 mm in the length direction and compressed so that the height of the test piece becomes 1/2 of the height before the load is applied. Obtain the compression stress per unit cross-sectional area. The cross-sectional area was determined by the thickness of the sponge × the length of the sponge.

(E) Tensile test (TB, EB)
A test piece was obtained by punching the upper part of the hot air-crosslinked tubular sponge in the length direction with a No. 3 type dumbbell described in JIS K6301 (1989). Using this test piece, a tensile test was conducted at a measurement temperature of 25 ° C. and a tensile speed of 500 mm / min in accordance with the method defined in JIS K6301 (1989), paragraph 3, tensile stress at break (TB), tensile fracture. Point elongation (EB) was measured.

(F) Compression set test The hot air-crosslinked tube-like sponge is cut to 30 mm in the length direction and attached to a compression device (device described in JIS K6301). The test piece was compressed so that the height before applying the load was 1/2 of the height before applying the load, and the mold was heat-treated in a gear oven under the following conditions. Subsequently, the heat-treated test piece was taken out from the compression apparatus, allowed to cool for 30 minutes, the height of the test piece was measured, and the compression set was calculated by the following formula.
Test condition 1: 22 hours at 70 ° C.
Test condition 2: 70 ° C. × 197 hours.
Test condition 3: 150 ° C. × 22 hours.
Compression set (%) = [(t0−t1) / (t0−t2)] × 100
t0: Height of the test piece before the test.
t1: Height of the test piece after heat-treating the test piece and allowing it to cool for 30 minutes after removal from the compression apparatus.
t2: Height of the test piece attached to the measurement mold.

(G) Measurement of total VOC amount In measuring the amount of volatile components, 2.0 g of the cut crosslinked sponge rubber was collected in a 20 ml vial and sealed. GC / MS analysis was performed about the volatile component when this was heated at 200 degreeC x 5 minutes, and the volatile component was quantified. The measurement conditions are as follows.
Apparatus: HP7694HS-HP6890GC / HP5973MS system separation column manufactured by HewLett Packard: HP-5MS 30 m 0.25 mmφ 0.25 μm
Column temperature: 40 ° C. (3 min) −10 ° C./min temperature increase—250 ° C.

(J) Odor measurement 10 g of a crosslinked sponge rubber is put into a 500 ml wide-mouthed bottle, and the cap is capped. Take out after heating for 10 minutes in an oven at 100 ° C. and check the generated odor. A sensory test is conducted by five panelists, and the superiority and inferiority are evaluated according to the following evaluation criteria.
<3-level odor intensity display standard>
3: The smell that can finally be detected.
2: A weak smell.
1: Smell that can be easily detected.

(K) Product appearance test A tube-like sponge cross-linked with hot air was cut into a length of 500 mm, and the smoothness of the product surface was visually determined.
Judgment criteria for 3-stage evaluation of product appearance 3: Smooth surface with no foaming.
2: The surface is slightly foamed.
1: 10 or more foams of 0.3 mm or more are seen on the surface.

(L) Measurement of presence / absence of foreign matter The hot-air crosslinked tubular sponge was cut into a length of 500 mm, and foreign matter having a size of 0.1 mm or more on the product surface was taken out. Sulfuric acid was added to the removed foreign matter, and it was ashed with a heater and an electric furnace. The incinerated product was dissolved in dilute sulfuric acid, pure and constant volume, and Na was qualitatively measured with an atomic absorption photometer, and foreign matter caused by baking soda was determined when Na was detected.
In addition, the extracted foreign matter was pulverized and subjected to an extraction test with ultrapure water. The citric acid in this solution was qualitatively determined by ion chromatography, and the one in which citric acid was detected was determined to be a foreign matter caused by citric acid. . When foreign matter caused by baking soda is detected, there is foreign matter of sodium bicarbonate, when foreign matter caused by citric acid is detected, there is foreign matter of citric acid, and when both are detected, there is foreign matter of sodium bicarbonate and citric acid, neither is detected In the case of sodium bicarbonate and citric acid.

"Examples 2-5, Comparative Examples 1-10"
In Example 1, instead of baking soda 1 and citric acid 2, sodium bicarbonate 1 to 6 and citric acid 1 to 5 were used, and the addition amount was changed as shown in Tables 3 to 4 in the same manner as in Example 1. went. The results are shown in Tables 3-4.

"Example 6"
120 parts by weight of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-1) shown in Table 1, 20 parts by weight of polyethylene [made by Mitsui Chemicals, trade name: Mirason FL60], carbon Black [Asahi Carbon Co., Ltd., trade name; Asahi # 60HG] 190 parts by weight, calcium carbonate [Shiraishi Calcium Co., Ltd., trade name Whiten SB] 30 parts by weight, softener [Idemitsu Kosan Co., Ltd., Product name: 70 parts by weight of Diana Process Oil ^TM PS-430] and 5 parts by weight of calcium oxide [Inoue Lime Industry Co., Ltd., trade name Vesta PP] with a capacity of 2.95 liter Banbury mixer [Kobe Steel Co., Ltd. Kneading].

  The kneading method involves first kneading ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-1) for 30 seconds, and then adding carbon black, polyethylene, calcium carbonate, softener, calcium oxide. Kneaded for 2 minutes. Thereafter, the ram was raised and cleaned, and further kneaded for 1 minute and discharged at about 160 ° C. to obtain a rubber compound (I-2). This kneading was performed at a filling rate of 75%.

Next, 435 parts by weight of this compound (I-2) was added to an 8-inch roll (front roll surface temperature 50 ° C., rear roll surface temperature 50 ° C., front roll rotation speed 18 rpm, rear roll rotation speed 15 rpm). 1 part by weight of baking soda 1 shown in Table 2 as a foaming agent, 0.5 part by weight of citric acid 1 shown in Table 2 as a foam nucleating agent, and (CH ₃ ) ₃ as a SiH group-containing compound (crosslinking agent) _{SiO - [- SiH (CH 3} ) -O-] 6 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) _{3 4} parts by weight [Shin-Etsu Chemical Co., Ltd.], a After 1-ethynyl-1-kneading cyclohexanol 0.3 parts by weight of a 10 minutes as a reaction inhibitor, 3% platinum concentration as a catalyst, platinum carbonyl Vinylmethyl cyclic siloxane solution of vinylmethyl complex 0 05 parts by weight [GELEST. After adding INc, trade name SIP6829.0] and kneading for 5 minutes, the kneaded product was separated into ribbons. The total amount of the kneaded material was about 2 kg. About the obtained uncrosslinked rubber compound, the scorch time and the crosslinking rate were measured by the methods described in the above (a) and (b).

  Next, the uncrosslinked rubber compound was added to a die temperature of 80 ° C. using a 50 mmφ extruder (manufactured by Mitsuba Corporation; L / D = 16) equipped with a flat die (20 mm wide, 2 mm long). It was extruded under the conditions of a cylinder temperature of 70 ° C. and a screw temperature of 50 ° C. to form a tape. This molded body was crosslinked with HAV (hot air vulcanization tank) at 230 ° C. for 5 minutes to obtain a crosslinked sponge rubber.

About the obtained crosslinked sponge rubber, specific gravity measurement, foaming ratio, tensile test, compression set test, total VOC, odor resistance, product appearance, presence / absence measurement of foreign matter, and hardness (JIS-A) were performed according to the following methods. . The results are shown in Table 5.
(A) Specific gravity measurement; described in (A) above.
(B) Foaming ratio: Described in (B) above.
(E) Tensile test (TB, EB); described in (E) above.

(N) Compression set test The hot-air cross-linked tape-like sponge is cut to 30 mm in the length direction, the prepared cross-linked foam sheet is laminated according to JIS K6250, and the compression set test is performed according to JIS K6262. It was. The test piece was compressed so that the height before the load was 1/4 of the height before the load was applied, and the mold was heat-treated in a gear oven under the following conditions. Subsequently, the heat-treated test piece was taken out from the compression apparatus, allowed to cool for 30 minutes, the height of the test piece was measured, and the compression set was calculated by the following formula.
Compression set (%) = [(t0−t1) / (t0−t2)] × 100
t0: Height of the test piece before the test.
t1: Height of the test piece after heat-treating the test piece and allowing it to cool for 30 minutes after removal from the compression apparatus.
t2: Height of the test piece attached to the measurement mold.
The test conditions are as follows.
Test condition 1: 22 hours at 70 ° C.
Test condition 2: 70 ° C. × 197 hours.
Test condition 3: 150 ° C. × 22 hours.

(G) Measurement of total VOC amount; described in (G) above.
(J) Odor measurement; described in (J) above.
(K) Product appearance test; described in (K) above.
(L) Measurement of presence or absence of foreign matter; described in (M) above.
(M) Hardness measurement Hardness (JIS-A) was measured according to JIS K6253 (1997).

"Examples 7 to 10, Comparative Examples 11 to 20"
In Example 1, instead of baking soda 1 and citric acid 1, as shown in Tables 5 to 6 using baking soda 1 to 6 and citric acid 1 to 5, the same as in Example 6 except that the addition amount was changed. went. The results are shown in Tables 5-6.

"Example 11"
100 parts by weight of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-2) shown in Table 1, carbon black [manufactured by Lion Corporation, trade name: Ketjen Black EC-600JD] 15 Banbury with a capacity of 2.95 liters by weight, carbon black [made by Showa Cabot Co., Ltd., trade name: N990] 20 parts by weight, and calcium oxide [Inoue Lime Industry Co., Ltd., trade name Vesta PP] by 3 parts by weight The mixture was kneaded with a mixer [manufactured by Kobe Steel, Ltd.].

  As a kneading method, ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-2) was first kneaded for 30 seconds, and then carbon black and calcium oxide were added and kneaded for 2 minutes. Thereafter, the ram was raised and cleaned, and further kneaded for 1 minute and discharged at about 135 ° C. to obtain a rubber compound (I-3). This kneading was performed at a filling rate of 75%.

Next, 138 parts by weight of this compound (I-3) was added to an 8-inch roll (front roll surface temperature 50 ° C., rear roll surface temperature 50 ° C., front roll rotation speed 18 rpm, rear roll rotation speed 15 rpm). 6 parts by weight of baking soda 1 shown in Table 2 as a foaming agent, 4 parts by weight of citric acid 1 shown in Table 2 as a foaming nucleating agent, and (CH ₃ ) ₃ SiO— as a SiH group-containing compound (crosslinking agent) _{[-SiH (CH 3) -O-]} 6 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6) 2 -O-] 1 -Si (CH 3) 3 4 Parts by weight [manufactured by Shin-Etsu Chemical Co., Ltd.], 0.2 parts by weight of 1-ethynyl-1-cyclohexanol as a reaction inhibitor and kneading for 10 minutes, followed by 3% platinum concentration platinum carbonylvinylmethyl as a catalyst Complex of vinyl methyl cyclic siloxane solution 0.0 Parts by weight of [GELEST. After adding INc, trade name SIP6829.0] and kneading for 5 minutes, the kneaded product was separated into ribbons. The total amount of the kneaded material was about 2 kg. With respect to the obtained uncrosslinked rubber compound, the scorch time and the crosslinking rate were measured by the above methods (a) and (b).

  Using this uncrosslinked rubber compound, a die temperature of 80 ° C., a cylinder temperature of 70 ° C., using a 50 mmφ extruder equipped with a circular die (diameter: 10 mm) (manufactured by Mitsuba Corporation; L / D = 16) Extruded under the condition of a screw temperature of 50 ° C. and formed into a round bar shape. This molded body was crosslinked with HAV (hot air vulcanization tank) at 230 ° C. for 5 minutes to obtain a crosslinked sponge rubber.

About the obtained crosslinked sponge rubber, specific gravity measurement, expansion ratio, water absorption measurement, compression set test, total VOC, odor resistance, product appearance, presence / absence measurement of foreign matter, hardness (Asker C) were performed according to the following methods. . Table 7 shows the evaluation results.
(A) Specific gravity measurement; described in (A) above.
(B) Foaming ratio: Described in (B) above.
(C) Water absorption rate: described in (C) above.

(P) Compression set resistance test A hot air-crosslinked round bar-like sponge is cut into a length of 30 mm and attached to a compression device (device described in JIS K6301). The test piece was compressed so that the height before applying the load was 1/2 of the height before applying the load, and the mold was heat-treated in a gear oven under the following conditions. Subsequently, the heat-treated test piece was taken out from the compression apparatus, allowed to cool for 30 minutes, the height of the test piece was measured, and the compression set was calculated by the following formula.
Test condition 1: 23 ° C. for 22 hours Test condition 2: 70 ° C. × 22 hours Test condition 3: 150 ° C. × 22 hours Compression set (%) = [(t0−t1) / (t0−t2)] × 100
t0: Height of the test piece before the test.
t1: Height of the test piece after heat-treating the test piece and allowing it to cool for 30 minutes after removal from the compression apparatus.
t2: Height of the test piece attached to the measurement mold.

(J) Odor measurement; described in (J) above.
(K) Product appearance test; described in (K) above.
(L) Presence / absence measurement of foreign matter: described in (M) above.
(R) Hardness measurement Asker C hardness was measured according to JIS K6253 (1997).

"Examples 12-15, Comparative Examples 21-30"
Instead of baking soda 1 and citric acid 1 in Example 1, as shown in Tables 7 to 8 using baking soda 1 to 6 and citric acid 1 to 5, the same procedure as in Example 11 was carried out except that the addition amount was changed. It was. The results are shown in Tables 7-8.

"Example 16"
100 parts by weight of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-3) shown in Table 1, clay [manufactured by Engelhard Co., Ltd., trade name: Translink 37], 50 parts by weight, And 3 parts by weight of calcium oxide [trade name Vesta PP, manufactured by Inoue Lime Industry Co., Ltd.] was kneaded with a 2 liter planetary mixer [manufactured by Inoue Seisakusho Co., Ltd.].

  As a kneading method, first, ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-3) was kneaded for 30 seconds, and then clay and calcium oxide were added and kneaded for 10 minutes. The kneading temperature was 25 ° C. to obtain a rubber compound (I-4). This kneading was performed at a filling rate of 75%.

In a planetary mixer, 153 parts by weight of this compound (I-4), 6 parts by weight of baking soda 1 shown in Table 2 as a foaming agent, 4 parts by weight of citric acid 4 shown in Table 2 as a foaming nucleating agent, SiH group-containing compound (crosslinking _{agent) (CH 3) 3 SiO -} [- SiH (CH 3) -O-] 6 - [- Si (CH 3) 2 -O-] 1 - [- Si (C 6 H 6 ) ₂ -O-] ₁ -Si (CH ₃ ) ₃ 4 parts by weight [manufactured by Shin-Etsu Chemical Co., Ltd.], 0.3 parts by weight of 1-ethynyl-1-cyclohexanol was added as a reaction inhibitor and kneaded for 10 minutes. Later, 0.05 parts by weight of a vinylmethyl cyclic siloxane solution of a platinum carbonyl vinylmethyl complex having a concentration of 3% platinum as a catalyst [GELES. After adding INc and trade name SIP6829.0] and kneading for 5 minutes, a kneaded product was obtained. The total amount of the kneaded material was about 1 kg.

This uncrosslinked rubber compound was packed into a commercially available sealing gun and extruded from a 10 mm diameter nozzle onto the plate. The extrudate was placed in a gear oven at 180 ° C. together with the plate and crosslinked for 10 minutes to obtain a sponge rubber. The obtained crosslinked sponge rubber was measured for specific gravity, odor resistance, product appearance, and presence / absence of foreign matter according to the following methods. Table 9 shows the evaluation results.
(A) Specific gravity measurement; described in (A) above.
(B) Odor measurement; described in (B) above.
(K) Product appearance test; described in (K) above.
(L) Presence / absence measurement of foreign matter; described in (M) above.

“Examples 17, 18, and 20, Comparative Examples 31 to 40”
In Example 16, instead of baking soda 1 and citric acid 1, as shown in Tables 9 to 10 using baking soda 1 to 6 and citric acid 1 to 5, the same as in Example 1 except that the addition amount was changed. went.
The evaluation results are shown in Tables 9-10.

"Example 19"
Instead of using ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-3) shown in Table 1, polyisobutylene [manufactured by Kaneka Co., Ltd., trade name: Epion 600A], The same operation as in Example 16 was performed. Table 9 shows the evaluation results.

According to the present invention, 1) light weight, excellent sealing, heat resistance, weather resistance, bloom resistance, contamination resistance, volatilization resistance, odor resistance, and smoothness of the rubber surface after foaming. Seal sponge, 2) Lightweight, cushion sponge with excellent cushion resistance, compression set resistance, weather resistance, bloom resistance, volatilization resistance, odor resistance, 3) Light weight, heat insulation, resistance Compression set, heat resistance, bloom resistance, volatilization resistance, odor resistance, heat insulating sponge with excellent smoothness of rubber surface after foaming 4) Light weight, compression set resistance, strength characteristics, Protective sponge with excellent heat resistance, weather resistance, bloom resistance, scratch resistance, volatilization resistance, odor resistance, and smoothness of the rubber surface after foaming. 5) Lightweight, flame retardant, compression resistance permanent Flame retardant sponge with excellent distortion, weather resistance, bloom resistance, volatilization resistance, foamed rubber surface smoothness, 6) Light weight, Compression set, abrasion resistance due to paper, heat resistance, Bull - applicable to Le - arm resistance, stain resistance of the photosensitive member, excellent foaming OA B to the smoothness of the rubber surface after foaming.

Claims (10)

Ethylene / propylene / non-conjugated polyene random copolymer rubber- containing organic polymer (A) containing vinyl group, SiH group-containing compound (B) having at least two SiH groups in one molecule, and platinum-based catalyst A rubber composition comprising (C), baking soda (D) and a foam nucleating agent (E) which is citric acid, and a foam nucleating agent (E) in the foam nucleating agent (E) and baking soda (D). % by weight is 20 to 80 wt% der of) is,
The non-conjugated polyene is 5-vinyl-2-norbornene;
The 1-4th quantile, which is an index of the particle size distribution of sodium bicarbonate (D), is 0.1-20 μm, the 3-4th quantile is 2-40 μm, and the particle size distribution (3-4 quantile / 1− The 4th quantile) is 2 to 10, the 1-4th quantile is 0.1 to 20 μm, and the 3rd to 4th quantile is 2 which is an index of the particle size distribution of the foam nucleating agent (E). A rubber composition capable of crosslinking and foaming, characterized by having a particle size distribution (3-4 quantile / 1-4 quantile) of 2 to 10 and ˜40 μm . The rubber composition capable of crosslinking and foaming according to claim 1 , wherein the average particle size of the baking soda (D) is 1 to 25 μm. The rubber composition according to claim 1 or 2, wherein the foam nucleating agent (E) has an average particle size of 1 to 25 µm. The organic polymer (A) containing a vinyl group has (1) a molar ratio of ethylene to propylene (ethylene / propylene ) in the range of 50/50 to 90/10, and (2) an iodine value of 1 to 30. in the range of, (3) an intrinsic viscosity measured in decalin solution of 135 ° C. [eta] is any one of claims 1 to 3, characterized in that the range of 0.1~5dl / g 1 The rubber composition which can be crosslinked and foamed as described in the item. Seal sponge obtained from crosslinkable foamable rubber composition according to any one of claims 1-4. Cushion sponge obtained from crosslinkable foamable rubber composition according to any one of claims 1-4. Insulation sponge obtained from crosslinkable foamable rubber composition according to any one of claims 1-4. Protected sponge obtained from crosslinkable foamable rubber composition according to any one of claims 1-4. Flame retardant sponge obtained from crosslinkable foamable rubber composition according to any one of claims 1-4. Foam rolls obtained from the crosslinkable foamable rubber composition according to any one of claims 1-4.