JP5065924B2 - Vulcanizable rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vulcanizable rubber composition which can be suitably used for manufacturing a molded product which allows weight saving, and moreover, is excellent in strength characteristics, designability, compression set property, and processability. <P>SOLUTION: The vulcanizable rubber composition comprises: an ethylene/&alpha;-olefin/nonconjugated polyene copolymer rubber (A) comprising ethylene, a 3-20C &alpha;-olefin, and a nonconjugated polyene; a polyolefin resin (B); and a foaming agent (C), and is a blend in which the polyolefin resin (B) is micro dispersed in the state of melting in the ethylene/&alpha;-olefin/nonconjugated polyene copolymer rubber (A), wherein the mean dispersion grain size of the polyolefin resin (B) is 2 &mu;m or less, the blend weight ratio of the polyolefin resin (B) with the ethylene/&alpha;-olefin/nonconjugated polyene copolymer rubber (A) [(B)/(A)] is 5/95 to 50/50, the foaming agent (C) is a non-support type, the amount of combination of the foaming agent (C) based on 100 pts.wt. of the ethylene/&alpha;-olefin/nonconjugated polyene copolymer rubber (A) is 0.05 to 0.4 pts.wt., the product of the vulcanized rubber obtained by carrying out the vulcanization of this has 0.8-1 of a specific density and/or the specific density of the rubber composition before the vulcanization is 1.0-1.18. The manufacturing method of the rubber composition and the rubber product which can be manufactured by carrying out the vulcanization of the rubber composition are provided. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vulcanizable rubber composition and its use. More specifically, the present invention relates to a vulcanizable rubber composition that can be reduced in weight and can provide a molded article having excellent strength characteristics, design properties, compression set resistance, and processability. The present invention relates to a vulcanizable rubber composition and its use.

  Conventionally, as a method for obtaining a vulcanizable low specific gravity rubber composition, the amount of a reinforcing agent (carbon black, silica, etc.) and an inorganic filler (talc, clay, calcium carbonate, etc.) having a higher specific gravity than rubber is minimized. And a method of blending a large amount of a low specific gravity compounding agent such as a tackifier or process oil is generally employed.

  However, in the former method, when a composition that can obtain a high hardness is used, the fluidity of the resulting rubber composition is poor, and roll processability, extrusion moldability, and injection moldability are extremely poor. Occurs.

  Furthermore, in the latter method, the fluidity is improved, but since a large amount of a softening agent such as process oil is blended, the resulting rubber composition has a low hardness, and its use is in a rubber product within a specific range. There is a disadvantage that it is limited.

  In order to solve such a problem, Patent Document 1 discloses a fine foam weather strip material including a main body based on rubber or thermoplastic resin and microcapsules dispersed in the main body. These microcapsules are characterized by being thermally expanded capsules containing low-boiling hydrocarbons and expanding at the vulcanization temperature. It is intended to reduce the specific gravity by slightly foaming with this microcapsule. However, as a result of the inventors trying the invention described in this publication, a weatherstrip material having a low specific gravity can be obtained. However, the microcapsules appear on the surface of the product, resulting in poor design and cost. It has been confirmed that there are problems such as high.

JP-A-6-183305

  The present invention is intended to solve the above-mentioned problems, and can be reduced in weight, and can be vulcanized to produce a molded article having excellent strength characteristics, design properties, compression set resistance, and workability. It is an object to provide a rubber composition.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention.

That is, the present invention includes the following inventions.
(1) A vulcanizable rubber composition, which is a vulcanized rubber product obtained by vulcanizing the rubber composition, has a hardness of 30 to 85, a specific gravity of 0.8 to 1, a tensile strength of 4 to 15 MPa, and a tensile elongation at break A vulcanizable rubber composition having 100 to 800%, compression set of 10 to 60%, and an average foamed cell diameter of 1 to 500 μm.
(2) an ethylene / α-olefin / nonconjugated polyene copolymer rubber (A), a polyolefin resin (B), and a foaming agent (C) composed of ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene; A vulcanizable rubber composition comprising a polyolefin resin (B) microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). The average dispersed particle size of the resin (B) is 2 μm or less, and the blend weight ratio of the polyolefin resin (B) and the ethylene / α-olefin / nonconjugated polyene copolymer rubber (A) [(B) / ( A)] is a rubber composition as described in said (1) which is 5/95-50/50.

(3) The rubber composition according to (2), wherein the foaming agent (C) is a non-supporting type.
(4) An ethylene / α-olefin / nonconjugated polyene copolymer rubber (A), a polyolefin resin (B), and a foaming agent (C) composed of ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene. A vulcanizable rubber composition comprising a polyolefin resin (B) microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). The average dispersed particle size of the resin (B) is 2 μm or less, and the blend weight ratio of the polyolefin resin (B) and the ethylene / α-olefin / nonconjugated polyene copolymer rubber (A) [(B) / ( A)] is 5/95 to 50/50, and the foaming agent (C) is a non-supporting vulcanizable rubber composition.

(5) An ethylene / α-olefin / non-conjugated polyene copolymer rubber (A)
(i) The molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is 50/50 to 80/20,
(ii) the iodine value is 10-40,
(iii) The intrinsic viscosity [η] measured in decalin at 135 ° C. is 2 to 7 dl / g,
(iv) The rubber composition according to any one of (2) to (4), wherein the branching index is 0.5 to 0.95.
(6) The rubber composition according to (5), wherein the polyolefin resin (B) is an ethylene homopolymer or a crystalline ethylene / α-olefin copolymer.

(7) The rubber composition according to (6), wherein the foaming agent (C) is at least one selected from the group consisting of an azo compound, a nitroso compound, a sulfonyl hydrazide compound, an azide compound, and an inorganic foaming agent.
(8) The rubber composition according to (7), wherein the foaming agent (C) has an average particle size of 0.1 to 15 μm.
(9) The above (1) to (8), wherein the rubber composition before vulcanization is Vm (125 ° C.) 20 to 90, Mooney scorch time 2 to 10 minutes at 125 ° C., and specific gravity 1.0 to 1.4. The rubber composition according to any one of the above.
(10) The rubber composition according to any one of (1) to (9), wherein the rubber composition before vulcanization has a workability index of 5 to 50.

(11) A polyolefin resin (B) is added to a rubber mixture composed of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an organic solvent in advance, kneaded and desolvated, and the polyolefin resin ( It can be obtained by preparing a kneaded product in which B) is uniformly dispersed in the copolymer rubber (A), and then blending and kneading the foaming agent (C) and other additives. The rubber composition according to (7).
(12) Ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), polyolefin resin (B) and other components as necessary, kneading temperature 80 to 250 ° C., kneading time 1 to 20 minutes, The rubber composition according to (7), which can be obtained by a method including a step of kneading under a condition of kneading / mixing specific energy of 0.001 to 10 Kw · h / kg.
(13) The rubber composition according to any one of (1) to (12), which is used for producing a weather strip for an automobile.

(14) Automotive weather strips include door weather strip, trunk weather strip, luggage weather strip, roof side rail weather strip, sliding door weather strip, ventilator weather strip, sliding loop panel weather strip, front window weather strip, rear window weather (13) which is a strip, quarter window weather strip, lock pillar weather strip, door glass outer weather strip, door glass inner weather strip, dam windshield, glass run channel, door mirror bracket, seal head lamp or seal cowl top The rubber composition as described.
(15) The rubber composition according to any one of (1) to (12), which is used for producing an automobile hose, a water supply hose, or a gas hose.

(16) The rubber composition according to (15), wherein the automobile hose is a brake hose, a radiator hose, a heater hose, or an air cleaner hose.
(17) The rubber composition according to any one of (1) to (12), which is used for producing a building material seal part.
(18) The rubber composition according to the above (17), wherein the building material seal part is a gasket, air tight, joint material or door stop.
(19) The rubber composition according to any one of (1) to (12), which is used for manufacturing home appliance seal parts.
(20) The rubber composition according to any one of (1) to (12), which is used for producing an automobile cup / sealant or an industrial machine sealant.

(21) The automotive cup / sealant is a master cylinder piston cup, wheel cylinder piston cup, constant velocity joint boot, pin boot, cast cover, piston seal, packing, O-ring, plug cap, plug boot, grommet or diaphragm. The rubber composition as described in (20) above.
(22) The rubber composition according to (20), wherein the sealing material for industrial machine is a capacitor packing, an O-ring or a packing.
(23) An ethylene / α-olefin / non-conjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene, wherein (i) ethylene and α having 3 to 20 carbon atoms The molar ratio (ethylene / α-olefin) with the olefin is 50/50 to 80/20, (ii) the iodine number is 10 to 40, and (iii) the intrinsic viscosity measured in decalin at 135 ° C. [ η] is 2 to 7 dl / g, and (iv) an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) having a branching index of 0.5 to 0.95 and an ethylene homopolymer or Polyolefin resin (B ′) which is a crystalline ethylene / α-olefin copolymer, and at least one foaming agent selected from the group consisting of azo compounds, nitroso compounds, sulfonyl hydrazide compounds, azide compounds and inorganic foaming agents ( C ′) is a vulcanizable rubber composition, and a polyolefin resin (B ′) is microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). It is a blend, the average dispersion particle size of the polyolefin resin (B ′) is 2 μm or less, and the polyolefin resin (B ′) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). In producing a vulcanizable rubber composition having a blend weight ratio [(B ′) / (A ′)] of 5/95 to 50/50, an ethylene / α-olefin / non-conjugated polyene copolymer is previously prepared. A polyolefin resin (B ′) is added to a rubber mixture composed of rubber (A ′) and an organic solvent, kneaded and desolvated, and the polyolefin resin (B ′) is added to the copolymer rubber (A ′). Uniformly dispersed kneaded material After preparing method of vulcanizable rubber composition characterized in that this is kneaded by blending other additives.

(24) An ethylene / α-olefin / nonconjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene, wherein (i) ethylene and α having 3 to 20 carbon atoms The molar ratio (ethylene / α-olefin) with the olefin is 50/50 to 80/20, (ii) the iodine number is 10 to 40, and (iii) the intrinsic viscosity measured in decalin at 135 ° C. [ η] is 2 to 7 dl / g, and (iv) an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) having a branching index of 0.5 to 0.95 and an ethylene homopolymer or Polyolefin resin (B ′) which is a crystalline ethylene / α-olefin copolymer, and at least one foaming agent selected from the group consisting of azo compounds, nitroso compounds, sulfonyl hydrazide compounds, azide compounds and inorganic foaming agents ( C ′) is a vulcanizable rubber composition, and a polyolefin resin (B ′) is microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). It is a blend, the average dispersion particle size of the polyolefin resin (B ′) is 2 μm or less, and the polyolefin resin (B ′) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). In producing a vulcanizable rubber composition having a blend weight ratio [(B ′) / (A ′)] of 5/95 to 50/50, an ethylene / α-olefin / non-conjugated polyene copolymer rubber ( A ′), polyolefin resin (B ′) and other additives as necessary, kneading temperature 80 to 250 ° C., kneading time 1 to 20 minutes, kneading and mixing specific energy 0.001 to 10 Kw · h / kg Knead under the conditions of A process for producing a vulcanizable rubber composition, comprising the step of:
(25) A rubber product that can be produced by vulcanizing the rubber composition according to any one of (1) to (22).

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition which can be reduced in weight and can manufacture the molded object which is excellent in an intensity | strength characteristic, designability, compression set resistance, and workability can be provided.

  The first invention of the present application is a vulcanizable rubber composition, and a vulcanized rubber product obtained by vulcanizing the rubber composition has a hardness of 30 to 85, a specific gravity of 0.8 to 1, and a tensile strength of 4 to 15 MPa. A vulcanizable rubber composition having a tensile elongation at break of 100 to 800%, a compression set of 10 to 60%, and an average foamed cell diameter of 1 to 500 μm.

  The vulcanizable rubber composition of the first invention of the present application is preferably an ethylene / α-olefin / non-conjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene. A vulcanizable rubber composition comprising (A), a polyolefin resin (B) and a foaming agent (C). In the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), a polyolefin resin ( B) is a blend obtained by microdispersing in a molten state, the polyolefin resin (B) has an average dispersed particle size of 2 μm or less, and the polyolefin resin (B) is co-polymerized with ethylene / α-olefin / non-conjugated polyene. The blend weight ratio [(B) / (A)] with the combined rubber (A) is 5/95 to 50/50.

  The second invention of the present application is an ethylene / α-olefin / nonconjugated polyene copolymer rubber (A), a polyolefin resin (B) and a foaming agent comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene. (C) A vulcanizable rubber composition comprising a blend of a polyolefin resin (B) in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). The average dispersion particle size of the polyolefin resin (B) is 2 μm or less, and the blend weight ratio of the polyolefin resin (B) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) [( B) / (A)] is 5/95 to 50/50, and the foaming agent (C) is a non-supporting vulcanizable rubber composition.

In the vulcanizable rubber composition of the first and second inventions of the present application, the rubber composition before vulcanization has a Mooney viscosity (Vm) ML _{1 + 4} (125 ° C.) of 20 to 90 to improve workability. It is preferable in terms of maintaining, and Mooney scorch time at 125 ° C. is preferably 2 to 10 minutes from the viewpoint of reducing the average foamed cell diameter, and specific gravity of 1.0 to 1.4 decreases the expansion ratio, and the product The workability index is preferably 5 to 50 from the standpoint of reducing the product variation (for example, the product dimensions after extrusion and the uniformity of the foamed cell diameter).

In the vulcanizable rubber composition of the first and second inventions of the present application, the specific gravity of the rubber composition before vulcanization is 1.0 to 1.3, 1.01 to 1.20, 1.01-1.19, 1.01-1.18, 1.01-1.17, 1.01-1.16, 1.01-1.15, 1.01-1.14, 1. 01 to 1.13 and 1.01 to 1.12.
The vulcanizable rubber composition of the preferred embodiment of the first invention of the present application and the components used in the vulcanizable rubber composition of the second invention of the present application are described in detail below.

Ethylene / α-olefin / non-conjugated polyene copolymer rubber (A)
The ethylene / α-olefin / nonconjugated polyene copolymer rubber (A) used in the present invention is a polymer obtained by random copolymerization of ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene.

  Specific examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11- Examples thereof include methyl-1-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.

  As the non-conjugated polyene, a cyclic or chain non-conjugated polyene can be used.

  Examples of the cyclic non-conjugated polyene include 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, and methyltetrahydroindene. Examples of the chain non-conjugated polyene include 1,4-hexadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4-ethylidene-1,7- Examples include undecadiene. These non-conjugated polyenes can be used alone or in admixture of two or more.

As the ethylene / α-olefin / non-conjugated polyene copolymer (A), those having the following characteristics are preferred.
(I) Molar ratio of ethylene to C3-C20 α-olefin (ethylene / α-olefin)
The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) comprises (a) a unit derived from ethylene and (b) an α-olefin having 3 to 20 carbon atoms (hereinafter sometimes simply referred to as “α-olefin”). Is a molar ratio of usually 50/50 to 80/20, preferably 55/45 to 80/20, more preferably 60/40 to 80/20, particularly preferably 65/45 to 75/15. [(A) / (b)].
When this molar ratio is within the above range, a rubber composition capable of providing a vulcanized rubber molded article having excellent heat aging resistance, strength characteristics and rubber elasticity, and excellent cold resistance and processability can be obtained.

(ii) Iodine value The iodine value of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is usually 10 to 40 (g / 100 g), preferably 10 to 30 (g / 100 g), more preferably. It is 10-25 (g / 100g), Most preferably, it is 10-20 (g / 100g).
When this iodine value is within the above range, a rubber composition having a high effective network chain density is obtained, and a vulcanized rubber molding having excellent compression set resistance and environmental degradation resistance (= heat aging resistance) is obtained. A rubber composition capable of providing a body is obtained and is advantageous in terms of cost.

(iii) Intrinsic viscosity The intrinsic viscosity [η] of the copolymer rubber (A) measured in decalin at 135 ° C. is usually 2 to 7 dl / g, preferably 2 to 5 dl / g, more preferably 2 to 4 dl. / G, particularly preferably 2.5 to 3.5 dl / g. When the intrinsic viscosity [η] is within the above range, a rubber composition capable of providing a vulcanized rubber molded article having excellent strength characteristics and compression set resistance and excellent workability can be obtained.

(iv) Branching index The branching index of the copolymer rubber (A) is usually 0.5 to 0.95, preferably 0.6 to 0.9, more preferably 0.65 to 0.9, particularly preferably. 0.7-0.9.

  When this branching index is in the above range, the workability index becomes a preferable range, the product shape becomes stable, and the pseudo gel is not easily formed during the kneading process, and the fluidity at the time of roll processing or extrusion processing is also obtained. Become good.

Here, the branching index indicates the relative degree of branching in the ethylene / α-olefin / non-conjugated polyene copolymer rubber, and was obtained by the following three types of experiments on polymer properties in solution. Calculated from numerical values.
(i) Weight average molecular weight ( _{Mw, LALLS} ) measured after gel permeation chromatography (GPC) using low angle light scattering ( _LALLS )
(ii) a differential refractometer connected to a GPC apparatus weight average molecular weight measured using a _{(DRI) (M w, DRI} ) and viscosity average molecular weight _{(M v, DRI)}
(iii) Intrinsic viscosity (IV) measured in decalin at 135 ° C
The measurements (i) and (ii) are obtained by GPC using a filtered, diluted 1,2,4-trichlorobenzene solution of polymer.

The average branching index (BI) is defined as the following equation (1).
[Equation 1]
BI = ( _{Mv , br} * _{Mw, DRI} ) / ( _{Mw, LALLS} * _{Mv , DRI} ) (1)
(Where M _{v, br} = k (IV) ^{1 / a} , M _{v, br} is the viscosity average molecular weight of the branched polymer, and a is a Mark-Houwink constant (ethylene · α- The olefin / non-conjugated polyene copolymer rubber is 0.759 in decalin at 135 ° C.)

  In the present invention, the copolymer rubber (A) can be used alone or in combination of two or more.

The copolymer rubber (A) having the above characteristics is preferably polymerized at a temperature of 35-60 ° C., particularly 35-59 ° C. in the presence of a catalyst containing the following compounds (I) and (II) as main components. The polymerization pressure is 4 to 12 kgf / cm ² , particularly 5 to 8 kgf / cm ² , and the molar ratio of the supply amount of non-conjugated polyene to ethylene (non-conjugated polyene / ethylene) is 0.05 to 0.2. It is obtained by random copolymerizing an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene. The copolymerization is preferably performed in a hydrocarbon medium.

(I) General formula: VO (OR) _a X _b or V (OR) _c X _d (wherein R is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom, and 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3 ≦ c + d ≦ 4)), or an electron donor adduct thereof.

As the vanadium compound represented by the above formula, the following formula:
VO (OR) _n X _3-n (wherein R is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom, and n is an integer of 0 or 1 to 3). A soluble vanadium compound or a vanadium compound represented by VX ₄ (wherein X is a halogen atom) is preferable.
The vanadium compound (I) is a component that is soluble in the hydrocarbon medium of the polymerization reaction system.

(II) R ′ _m AlX ′ _3-m [wherein R ′ is a hydrocarbon group having 1 to 12 carbon atoms, X ′ is a halogen atom, a hydrogen atom or OR ″ (where R ″ is the number of carbon atoms] 1 to 12 hydrocarbon groups), and m is 1 to 3. ] The organoaluminum compound represented by this.

  In the present specification, the hydrocarbon group having 1 to 12 carbon atoms is, for example, an alkyl group, a cycloalkyl group, or an aryl group, and specifically includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an isobutyl group. Pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like. The halogen atom is, for example, a chlorine atom or a bromine atom.

Specific examples of the soluble vanadium compound (I) include 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 and the like, vanadium Examples of the electron donor adduct of compound (I) include VCl ₃ · 2OC ₆ H ₁₂ OH.

Specific examples of the organoaluminum compound (II) include trialkylaluminum such as trimethylaluminum, triethylaluminum, tributylaluminum, triisopropylaluminum and triisobutylaluminum; dialkylaluminum alkoxide such as diethylaluminum ethoxide and dibutylaluminum butoxide; ethyl Alkyl aluminum sesquialkoxides such as aluminum sesquiethoxide and butylaluminum sesquibutoxide;
Partially alkoxylated alkylaluminum having an average composition represented by R ¹ _0.5 Al (OR ¹ ) _0.5 (wherein R ¹ is a hydrocarbon group having 1 to 12 carbon atoms) ;
Dialkylaluminum halides such as diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide; Partially halogenated alkylaluminums such as alkylaluminum dihalides such as: Dialkylaluminum hydrides such as diethylaluminum hydride and dibutylaluminum hydride; Partially such as alkylaluminum dihydrides such as ethylaluminum dihydride and propylaluminum dihydride Hydrogenated alkyl alcohol Bromide; ethyl aluminum ethoxy chloride, butyl aluminum butoxide cycloalkyl chloride, etc. partially alkoxylated and halogenated alkylaluminum such as ethylaluminum ethoxy bromide and the like.

  Moreover, as a catalyst used in the copolymerization, a so-called metallocene catalyst, for example, a metallocene catalyst described in JP-A-9-40586 is used in combination with a promoter such as methylaluminoxane (MAO). Even if it uses, the effect equivalent to the case where the catalyst containing the said compounds (I) and (II) as a main component is used can be acquired.

Polyolefin resin (B)
The polyolefin resin (B) used in the present invention is a thermoplastic resin, specifically, high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene. (LLDPE) or other ethylene homopolymers or crystalline ethylene / α-olefin copolymers composed of ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 3 to 8; propylene homopolymer, propylene block copolymer Polypropylene such as coalesced or propylene random copolymer; 3 to 20 carbon atoms such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, preferably 3-8 Examples thereof include crystalline homopolymers or copolymers of α-olefins. The melting point of these polyolefins is 250 ° C. or less. Among these, polyethylene and polypropylene are preferable, and polyethylene is particularly preferable.

  In the present invention, the blend weight ratio [(B) / (A)] of the polyolefin resin (B) and the ethylene / α-olefin / non-conjugated polyene copolymer (A) is usually 5/95 to 50/50. , Preferably 10/90 to 40/60. If polyolefin resin is used within this range, rubber elasticity can be maintained.

  Polyolefin resin (B), such as polyethylene, has the effect of increasing the product hardness of carbon black compared to reinforcing agents and fillers, as well as reducing the compound viscosity at the processing temperature and improving the processability. Used as an agent. Among them, polyethylene is preferable because of its great effect.

  In the present invention, the average particle diameter (determined from an electron micrograph) of the polyolefin resin (B) microdispersed in a molten state in the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is usually 2 μm or less. When the average particle size is 2 μm or less, the polyolefin resin does not disturb the surface layer as a foreign substance, and the compression set is good. The average particle diameter is preferably 1 μm or less, more preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. The aspect ratio (major axis / minor axis) of the dispersed particles of the polyolefin resin (B) is preferably 5 or less, more preferably 3 or less. When this aspect ratio is 5 or less, the micro-dispersion of the polyolefin resin (B) particles is good. Here, the micro-dispersion means that the polyolefin resin (B) is uniformly and finely dispersed in the ethylene / α-olefin / non-conjugated polyene copolymer (A).

Blending method As a method of mixing the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the polyolefin resin (B), a Banbury mixer, an internal mixer, a kneader, an open roll, etc. which are usually used as a rubber kneader May be used, as necessary, together with other components such as reinforcing agents, fillers, plasticizers, and the like at a temperature equal to or higher than the melting point of the polyolefin resin (B). Since the poor kneading product of B) is likely to be a foreign matter, the kneading temperature is 80 to 250 ° C., the kneading time is 1 to 20 minutes, preferably 1 to 10 minutes, and the kneading / mixing specific energy 0.001 to 10 Kw · h / Kneading is preferably performed under the condition of kg.

  As another preferable kneading method, as described below, the polyolefin resin (B) is added in advance to a rubber mixture composed of the copolymer rubber (A) and an organic solvent, and kneaded and desolvated. After preparing a kneaded product in which the polyolefin resin (B) is uniformly dispersed in the copolymer rubber (A), a reinforcing agent, a filler, a plasticizer, a foaming agent (C) and the like are added thereto. A method of blending and kneading the agent may be mentioned.

  A preferred embodiment of the latter kneading method will be described with reference to FIG. FIG. 1 is an example of a multistage vented extruder used in this method, and is a schematic view of a twin-screw three-stage vented extruder.

  The pellets prepared by this method are pellets of a rubber composition comprising an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and a polyolefin resin (B).

  First, using an extruder equipped with a pelletizer, a rubber mixture (E) composed of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an organic solvent (D), and a polyolefin resin (B) It knead | mixes and granulates and the rubber composition pellet which consists of ethylene-alpha-olefin-nonconjugated polyene copolymer rubber (A) and polyolefin resin (B) is prepared.

  The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the polyolefin resin (B) are as described above.

  As said organic solvent (D), the conventionally well-known hydrocarbon solvent used when preparing ethylene * alpha-olefin * nonconjugated polyene copolymer rubber in a solution polymerization method is mentioned. Specific examples of such hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, kerosene and their halogen derivatives, and alicyclic rings such as cyclohexane, methylcyclopentane, and methylcyclohexane. Aromatic hydrocarbons and their halogen derivatives, aromatic hydrocarbons such as benzene, toluene and xylene, and halogen derivatives such as chlorobenzene are used. These solvents may be used alone or in combination.

  As described above, the rubber mixture (E) is a mixture of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the organic solvent (D). The content of the organic solvent (D) in the rubber mixture (E) is 3 to 10 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A).

  In this method, for example, an ethylene / α-olefin / nonconjugated polyene copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a nonconjugated polyene is preferably produced by a solution polymerization method. In this case, the content of the organic solvent (D) in the obtained ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) solution was changed to ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) 100. The rubber mixture (E) is adjusted to 3 to 10 parts by weight with respect to parts by weight, and the resulting rubber mixture (E) is supplied to the feed section 2 of a multistage vented extruder (in FIG. 1, a twin-screw three-stage vented extruder) 1. Then, it is introduced into the extruder 1.

  At the same time, the polyolefin resin (B) is introduced into the extruder 1 from the other supply unit 3 in an inert gas atmosphere, and the rubber mixture (E) and the polyolefin resin (B) are kneaded and desolventized. By doing this, a rubber composition comprising the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the polyolefin resin (B) is obtained, and at that time, a pelletizer ( If it is granulated, a pellet of the rubber composition is obtained. Moreover, if a flyable bale molding machine is attached instead of the pelletizer, a bale of the rubber composition can be obtained.

  Although not shown in FIG. 1, the polyolefin resin (B) measured by the thermoplastic resin meter is transferred to the oxygen displacement device, and after the oxygen is removed using an inert gas by the oxygen displacement device, the extrusion is performed. It is supplied to the polyolefin resin supply unit 3 of the machine 1.

  Specific examples of the inert gas include nitrogen gas and argon gas, and nitrogen gas is preferably used. In this method, since the polyolefin resin (B) is supplied to the extruder using an inert gas, it is possible to obtain rubber composition pellets in which oxidation deterioration is prevented.

  The mixing ratio of the rubber mixture (E) and the polyolefin resin (B) is controlled by keeping the number of rotations of the screw of the extruder 1 and the supply amount of the polyolefin resin (B) from the thermoplastic resin meter constant. Is done. Further, the supply amount of the polyolefin resin (B) is stabilized by subtracting the pressure of the polyolefin resin supply unit 3 from the pressure in the oxygen substitution device.

  The solvent released by the desolvation is released from the vent hole 4 to the outside of the extruder 1 and collected.

  Further, the rubber composition in the extruder 1 manufactured as described above is taken out from the take-out port 5 in the form of pellets or bale.

  The oil expansion can be performed in the presence of a solvent in the ethylene / α-olefin / non-conjugated polyene copolymer rubber before being supplied to the extruder 1.

  The rubber composition pellets prepared as described above are usually a normal rubber kneader such as a Banbury mixer, an intermix, a kneader, a reinforcing agent such as carbon black, a filler such as talc and clay, It is kneaded with compounding agents such as a plasticizer (softener), a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, a processing aid, a pigment, an anti-aging agent, a foaming agent (C), and a foaming aid. The polyolefin resin (B) in the rubber compound obtained by this kneading has a very good dispersion state.

Foaming agent (C)
Specific examples of the foaming agent used in the present invention include inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite; N, N′-dimethyl-N, N′-di Nitroso compounds such as nitrosoterephthalamide and N, N'-dinitrosopentamethylenetetramine; azo compounds such as azodicarbonamide, azobisisobutyronitrile, azobiscyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzene Sulfonyl hydrazide compounds such as sulfonyl hydrazide, toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide) (OBSH), diphenylsulfone-3,3'-disulfonyl hydrazide; calcium azide, 4,4'-dipheni Disulfonyl azide and azide compounds such as p- toluenesulfonyl azide and the like.

  In the vulcanizable rubber composition of the first invention of the present application, as the foaming agent, either a non-supporting type or a supporting type supported on an inorganic powder or the like may be used, but a supporting type was used. The non-supported type is preferable in that it has a low water absorption at the same specific gravity compared to the case, has excellent sealing performance (soundproofing, waterproofing, vibration proofing), and is excellent in kneading workability into the compound. .

  In the vulcanizable rubber composition of the second invention of the present application, an unsupported type is used as the foaming agent.

  In the present invention, in order to obtain a weight-reducing material having a specific gravity of 1 or less and to obtain good rubber elasticity (Cs) and hardness, the foaming agent is used with respect to 100 parts by weight of the copolymer rubber (A). Usually, 0.001 to 5 parts by weight is used. The blending amount of the foaming agent is preferably 0.05 to 4 parts by weight, more preferably 0.05 to 3 parts by weight, still more preferably 0.05 to 1 part by weight, particularly preferably 0.05 to 0.6 parts by weight, Most preferably, it is 0.1-0.4.

  Moreover, in order to obtain favorable product surface skin and uniform foamed cells, the average particle size of the foaming agent is usually 0.1 to 15 μm. The average particle diameter of the foaming agent is preferably 0.5 to 10 μm, more preferably 1 to 5 μm.

Other additives In addition to the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), the polyolefin resin (B) and the foaming agent (C), the rubber composition of the present invention is reinforced as necessary. Agents, fillers, plasticizers (softeners), vulcanizing agents, vulcanization accelerators can be included.

  Examples of the reinforcing agent include various carbon blacks such as SRF, GPF, FEF, MAF, HAF, ISAF, SAF, FT, and MT; finely divided silicic acid and silica.

  As the carbon black, GPF, FEF, MAF, and HAF are preferable because of excellent balance between workability and hardness. Carbon black is usually used at a ratio of 20 parts by weight or more with respect to 100 parts by weight of the copolymer rubber (A) in order to obtain good mechanical strength, Cs, and product hardness. The amount of carbon black is preferably 50 to 200 parts by weight, more preferably 60 to 180 parts by weight.

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 these 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 application, but the total blending amount of the rubber reinforcing agent as a whole is usually 100 wt.% Of ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). Part by weight, up to 300 parts by weight, preferably up to 200 parts by weight.

  Examples of the filler include inorganic fillers such as 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 100 parts by weight of ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). On the other hand, the maximum is 300 parts by weight, preferably 200 parts by weight.

  As the plasticizer (softener), a plasticizer usually used for rubber is used. Specifically, process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, petroleum jelly, coal tar, castor oil, linseed oil, sub, beeswax, palmitic acid, stearic acid, barium stearate, calcium stearate, laurin Examples thereof include zinc acid, atactic polypropylene, and coumaroindene resin. Among these, process oil and paraffin oil are particularly preferably used.

  In order to obtain good kneadability, the plasticizer is usually used in a proportion of 30 parts by weight or more with respect to 100 parts by weight of the copolymer rubber (A). When process oil is used as the plasticizer, the amount thereof is preferably 50 to 150 parts by weight, more preferably 60 to 120 parts by weight, based on 100 parts by weight of the copolymer rubber (A).

  Examples of the vulcanizing agent used in the present invention include sulfur, a sulfur compound, and an organic peroxide.

  Specific examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur and the like.

  Specific examples of the sulfur compound include sulfur chloride, sulfur dichloride, and polymer polysulfide. Also usable are sulfur compounds that release and vulcanize active sulfur at the vulcanization temperature, such as morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, and the like.

  In the present invention, the sulfur or sulfur compound is usually 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.3 parts per 100 parts by weight of the copolymer rubber (A). Used in a proportion of ~ 3 parts by weight.

  Moreover, when using sulfur or a sulfur compound as a vulcanizing agent, it is preferable to use a vulcanization accelerator together. Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N-diisopropyl-2-benzothiazole sulfenamide. , 2-mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, dibenzothiazyl disulfide, and the like; diphenylguanidine , Guanidine compounds such as triphenylguanidine, diorthonitrile guanidine, orthonitrile biguanide, diphenylguanidine phthalate; acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine Aldehyde amines such as acetaldehyde ammonia and aldehyde-ammonia compounds; imidazoline compounds such as 2-mercaptoimidazoline; thiourea compounds such as thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea; tetramethyl Thiuram compounds such as thiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, ethylphenyl Zinc dithiocarbamate, zinc butylphenyl dithiocarbamate, dimethyldithiocarbamate Thorium, dimethyldithiocarbamate selenium dithiocarbamate compounds such as dimethyl dithiocarbamate tellurium; dibutyl Ruki xanthate-based compounds such as Santo Gen zinc; may include compounds such as zinc oxide (zinc white).

  Vulcanization accelerators may be used alone, but are preferably used in combination of two or more.

  In this invention, a vulcanization accelerator is 0.1-20 weight part normally with respect to 100 weight part of copolymer rubber (A), Preferably it is 0.5-15 weight part, More preferably, it is 1-10. Used in parts by weight.

Rubber composition In addition to the additives described above, the rubber composition of the present invention includes, as necessary, foaming aids, processing aids, anti-aging agents, heat stabilizers, weathering stabilizers, antistatic agents, and coloring. An agent, a lubricant, a thickener, and other rubber compounding agents can be blended within a range not impairing the object of the present invention.

The vulcanizable rubber composition of the present invention can be prepared, for example, by the following method.
That is, the polyolefin resin (B) is melt blended in advance with the copolymer rubber (A) at a temperature equal to or higher than the melting point of the polyolefin resin (B), and the polyolefin resin (B) is converted into the copolymer rubber (A). ) Resin alloy ethylene / α-olefin copolymer rubber dispersed in an average particle size of 2 μm or less. To this, carbon black, plasticizer, and if necessary, zinc white, stearic acid, and other additives are blended, and a mixer such as a Banbury mixer at a temperature of 80 to 250 ° C. for about 1 to 20 minutes, Preferably, after kneading for about 1 to 10 minutes, using a roll such as an open roll, a foaming agent (C), a vulcanizing agent, a vulcanization accelerator, if necessary, a defoaming agent, a foaming aid, A rubber composition for extrusion is obtained by adding and mixing a vulcanization aid, kneading at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then dispensing.

  Alternatively, the copolymer (A) is blended with the polyolefin (B), carbon black, a plasticizer, and, if necessary, zinc white, stearic acid, and other additives, and mixers such as Banbury mixers. After kneading at a temperature of 80 to 250 ° C. for about 1 to 20 minutes, using a roll such as an open roll, a foaming agent (C), a vulcanizing agent, a vulcanization accelerator, and defoaming as necessary An additive, a foaming aid, and a vulcanization aid are additionally mixed, kneaded at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then dispensed to obtain a rubber composition for extrusion.

  The rubber composition thus obtained (vulcanizable rubber composition) is a ribbon-like or sheet-like rubber compound.

  The rubber compound (vulcanizable rubber composition) obtained as described above can be molded by a transfer molding method, an injection molding method, or a mold molding method. In general, the ribbon-like compound obtained by the above method is extruded into a product shape with a rubber extruder, and then introduced into a vulcanizing tank, and heated air, fluidized bed, molten salt tank (LCM), PCM ( It can be prepared by vulcanization and foaming by heating by means such as Powder Curing Medium or Powder Curing Method) or microwave. Preferably, hot air vulcanization tank (HAV), molten salt tank (LCM), PCM (Powder Curing Medium or Powder Curing Method), or continuous using hot air vulcanization tank (HAV) and decimeter wave (UHF) Continuously vulcanized and foamed by extrusion.

  If at least one of the above vulcanization methods can provide a vulcanized rubber product satisfying the required physical properties described later, it corresponds to the vulcanizable rubber composition of the first invention of the present application.

  The normal vulcanization conditions of the composition of the present invention are a vulcanization temperature of 160 to 280 ° C. and a vulcanization time of 1 to 20 minutes, and vulcanization satisfying the necessary physical properties described later in at least one of these conditions. If a rubber product can be obtained, it corresponds to a preferred rubber composition among the vulcanizable rubber compositions of the first invention of the present application. Particularly typical vulcanization conditions for the composition of the present invention are a vulcanization temperature of 250 ° C. and a vulcanization time of 5 minutes.

  The vulcanizable rubber composition of the first invention of the present application is a product of vulcanized rubber obtained by vulcanizing this in terms of obtaining good mechanical strength, compression set, product skin and shape retention. It is necessary that the hardness is 3085, the specific gravity is 0.8 to 1, the tensile strength is 4 to 15 MPa, the tensile breaking elongation is 100 to 800%, the compression set is 10 to 60%, and the average foamed cell diameter is 1 to 500 μm.

  The rubber composition of the present invention can be used as a lightweight product for automobile weather strips, such as door weather strips, trunk weather strips, luggage weather strips, roof side rail weather strips, sliding door weather strips, ventilator weather strips, sliding loop panel weathers. Strip, Front window weather strip, Rear window weather strip, Quarter window weather strip, Lock pillar weather strip, Door glass outer weather strip, Door glass inner weather strip, Dam windshield, Glass run channel, Door mirror bracket, Seal head lamp, Seal cowl top; automotive hoses such as brake hoses, radiators -Hose, heater hose, air cleaner hose; water supply hose; gas hose; building material seal parts such as gaskets, air tights, joint materials, door stops; home appliance seal parts; automotive cup seal materials such as master cylinder piston cups , Wheel cylinder piston cup, constant velocity joint boot, pin boot, cast cover, piston seal, packing, O-ring, plug cap, plug boot, grommet, diaphragm; suitable for industrial machinery sealing materials such as condenser packing, O-ring, packing Thus, a lightweight rubber product can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples, but the scope of the present invention is not limited to these examples.

Various physical properties described below and test methods thereof are as follows.
(1) Composition of copolymer rubber The composition of the copolymer was measured by ¹³ C-NMR method.
(2) Iodine value of copolymer rubber The iodine value of the copolymer rubber was determined by a titration method.
(3) Intrinsic viscosity [η]
The intrinsic viscosity [η] of the copolymer rubber was measured in decalin at 135 ° C.
(4) Branching index It calculated from the numerical value obtained by the following three types of experiments.

(i) Weight average molecular weight ( _{Mw, LALLS} ) measured after gel permeation chromatography (GPC) using low angle light scattering ( _LALLS )
Measurements were made using a LALLS detector connected to a GPC device.
(Measurement condition)
Device: Waters 150C
Detector: Chromatix KMX-6
Column: Shodex UT-806M (30 cm x 2), UT-807 (30 cm x 1)
Solvent: 1,2,4-trichlorobenzene Temperature: 135 ° C
Flow rate: 0.764 ml / min Concentration: 0.03-0.07% (w / v)
Injection volume: 300 μl

(ii) a differential refractometer connected to a GPC apparatus weight average molecular weight measured using a _{(DRI) (M w, DRI} ) and viscosity average molecular weight _{(M v, DRI)}
(Measurement condition)
Device: Waters 150C
Detector: DRI (150C built-in)
Column: Shodex UT806MLT (50cm x 1)
Solvent: 1,2,4-trichlorobenzene Temperature: 135 ° C
Flow rate: 1 ml / min Concentration: 0.2% (w / v)
Injection volume: 160 μl

Various average molecular weights were calculated in terms of EPDM conversion values. The viscosity formula used for conversion is as follows.
[Η] = 2.92 × 10 ⁻⁴ M _w ^0.726

(iii) Intrinsic viscosity (IV) measured in decalin at 135 ° C
Viscosity was measured at four points for concentration preparation by a multipoint method using an Ubbelohde viscometer, and the relationship between each measurement point was extrapolated to zero concentration.

  The measured values of (i) and (ii) were obtained by GPC using a filtered, diluted 1,2,4-trichlorobenzene solution of polymer.

  The average branching index (BI) is defined as the following equation (1).

[Equation 2]
BI = ( _{Mv , br} * _{Mw, DRI} ) / ( _{Mw, LALLS} * _{Mv , DRI} ) (1)
(Where M _{v, br} = k (IV) ^{1 / a} , M _{v, br} is the viscosity average molecular weight of the branched polymer, and a is a Mark-Houwink constant (ethylene · α- The olefin / non-conjugated polyene copolymer rubber is 0.759 in decalin at 135 ° C.)

(5) Mooney viscosity (Vm) ML _{1 + 4}
Conforms to JIS K6300 (1994).
Rotor shape: L rotor preheating time: 1 minute Test temperature: 125 ° C
(6) Mooney scorch time (t ₅ )
Conforms to JIS K6300 (1994).
Rotor shape: L rotor preheating time: 1 minute Test temperature: 125 ° C
(7) Specific gravity of unvulcanized rubber The rubber compound was punched into a 2 mm × 20 mm × 20 mm test piece, and the surface was wiped off with alcohol. Next, this test piece is attached to a predetermined position of an automatic hydrometer [manufactured by Toyo Seiki Seisakusho, Model No. M-1] in an atmosphere of 25 ° C., and the specific gravity is determined from the difference in mass between air and pure water. Measurements were made.
(8) Processability index Measures the frequency dispersion of complex viscosity η ^* using a dynamic viscoelasticity tester for ethylene / propylene copolymer rubber (EPR) (4 samples with different molecular weights) without long chain branching. did. 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 calculated. 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 · s was measured.

The values of η _1L0 ^* and η _1B0 ^* measured as described above were applied to the following formula to calculate the workability index.
_Workability index = (log η _1L0 ^* −log η _1B0 ^* ) × 10
The measurement conditions are as follows.

Reference sample: 4 types of EPR
Made by 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 ℃
・ Distortion rate: 1%
-Frequency dependence: 0.001-500 rad / sec

(9) Die swell Ribbon-like rubber compound is extruded at a speed of 2.5 m / min using a die of 2 mm in length and 25 mm in width in an extruder with an extruder head temperature of 80 ° C. The lateral length L of the sample after extrusion was measured and determined by the following formula.
Die swell (%) = L mm / 25mm x 100
(10) Specific gravity of vulcanized rubber A test piece of 20 mm × 20 mm was punched from the upper part of the vulcanized tubular sample, and the surface was wiped off with alcohol. Next, this test piece is attached to a predetermined position of an automatic hydrometer [manufactured by Toyo Seiki Seisakusho, Model No. M-1] in an atmosphere of 25 ° C., and the specific gravity is determined from the difference in mass between air and pure water. Measurements were made.
(11) Tensile test According to JIS K6251, a tensile test was performed under the conditions of a measurement temperature of 23 ° C and a tensile speed of 500 mm / min, and the strength at break (TB) and the elongation at break (EB) were measured.

(12) Hardness Measured according to JIS K6253. The flat portions of the vulcanized tube-like sample were overlapped to 12 mm, and the product hardness was determined with a durometer A.
(13) Compression set test It was extracted from the vulcanized molded article according to the method of JIS K6250 (1998) 6.5 and measured according to JIS K6262 (1997).
Conditions: 70 ° C. × 22 hours after processing, taken out, 30 minutes later, the thickness of the product was determined.
(14) Average foamed cell diameter The average foamed cell diameter was measured using a microscope [manufactured by KEYENCE, trade name: VH-6200]. The average foam cell diameter was an average value of 50 foam cells arbitrarily selected.

(15) Water absorption
(i) The weight of the sample was measured. (W ₁ )
(ii) The pressure was reduced to 635 mmHg using a desiccator and left for 3 minutes.
(iii) The atmospheric pressure was returned to 1 atm, and the sample weight was measured. (W ₂ )
The water absorption was calculated from the following formula.
Water absorption rate (%) = [(W ₂ −W ₁ ) / W ₁ ] × 100

Production Example 1 Production of Ethylene / Propylene / 5-Ethylidene-2-Norbornene Random Copolymer Rubber (A-1) Stainless Steel Polymerizer with Stirring Blades and 100 L in Internal Volume (Agitation Rotation Speed = 250 rpm) Was used for continuous terpolymerization of ethylene, propylene and 5-ethylidene-2-norbornene (ENB). From the side of the polymerization vessel to the liquid phase, 60 liters of hexane, 3.3 kg of ethylene, 9.2 kg of propylene, 320 g of 5-ethylidene-2-norbornene, 5 N liters of hydrogen, VO as a catalyst (OEt) Cl ₂ was continuously fed at a rate of 45 mmol and Al (Et) _1.5 Cl _1.5 at a rate of 315 mmol.

  When the copolymerization reaction was carried out under the conditions described above and shown in Table 1, an ethylene / propylene / 5-ethylidene-2-norbornene random copolymer (A-1) was obtained in a uniform solution state.

  Thereafter, a small amount of methanol is added to the polymerization solution continuously withdrawn from the lower part of the polymerization vessel to stop the polymerization reaction, and the polymer is separated from the solvent by a steam stripping treatment, followed by vacuum drying at 55 ° C. for 48 hours. went.

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

(Production Example 2) Production of ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-2) As a non-conjugated polyene, 5-vinyl-2-norbornene (VNB) was used. An ethylene / propylene / 5-vinyl-2-norbornene random copolymer rubber (A-2) was produced in the same manner as in Production Example 1 except that the conditions shown were used. Table 1 shows the physical properties of the copolymer rubber (A-2).

＊１：Ａｌ（Ｅｔ）_１．５Ｃｌ_１．５／ＶＯ（ＯＥｔ）Ｃｌ_２
＊２：ＶＯ（ＯＥｔ）Ｃｌ_２の触媒フィード

_{* 1: Al (Et) 1.5} Cl 1.5 / VO (OEt) Cl 2
* 2: VO (OEt) Cl ₂ catalyst feed

Example 1
The hexane solvent content of the hexane solution of the ethylene / propylene / 5-ethylidene-2-norbornene random copolymer rubber (A-1) prepared in Production Example 1 is 7 parts by weight with respect to 100 parts by weight of the rubber. And a rubber composition containing a hexane solvent was obtained.

The rubber composition was introduced at 1.667 kg / hr into the twin-screw three-stage vented extruder shown in FIG. 1, and polyethylene (B-1) [Mitsui Chemicals, Inc.] from the polyolefin resin supply section of the extruder. Manufactured, trade name: Mirason 68, density: 0.921 g / cm ³ , MFR (ASTM D1238, 190 ° C., 2.14 kg): 1.6 g / 10 min] were introduced into the extruder at 0.333 kg / hr. , Ethylene / propylene / 5-ethylidene-2-norbornene random copolymer rubber (A-1) and polyethylene (B-1) were kneaded and desolvated, and the resulting rubber was pelletized at the tip of the extruder After cutting, a pellet of blend (I) was obtained at a rate of 2.0 kg / hr.

  The blend weight ratio of polyethylene (B-1) and ethylene / propylene / 5-ethylidene-2-norbornene random copolymer rubber (A-1) in the obtained blend (I) was 20/100. .

  The average dispersed particle diameter of polyethylene (B-1) in the obtained blend (I) was measured as follows using an electron microscope [trade name H-8100 (200 KV), manufactured by Hitachi, Ltd.]. When the measured sample was measured, the average dispersed particle size was 0.01 μm or less.

<Sample preparation>
The pellets of the blend (I) were trimmed to produce a thin film piece of 0.1 μm or less with a microtome, and this thin film piece was dyed with ruthenic acid. Subsequently, carbon was vapor-deposited on this thin film piece to obtain a sample for an electron microscope.

120 parts by weight of the obtained blend (I), 70 parts by weight of FEF grade carbon black [Asahi Carbon Co., Ltd., trade name Asahi # 60G], carbon black [Asahi Carbon Co., Ltd., trade name Asahi F- 200G] 70 parts by weight, softener [Idemitsu Kosan Co., Ltd., Diana Process Oil ^TM PS-430] 100 parts by weight, stearic acid 1 part by weight, zinc white No. 1 5 parts by weight, activator [manufactured by Lion Corporation, 1 part by weight of trade name ARCARD 2HT-F] was kneaded with a 1.7 liter Banbury mixer [BB-2 mixer manufactured by Kobe Steel, Ltd.].

  In the kneading method, the blend (I) was first kneaded for 1 minute, and then carbon black, softener, stearic acid, zinc white and activator were added and kneaded for 2 minutes. Thereafter, the ram was raised and cleaned, and further kneaded for 2 minutes to obtain 1390 g of rubber compound (I). This kneading was carried out at a filling rate of 75%, and further, two batches were kneaded according to the same procedure to obtain a total of 4170 g. The processability index was measured for the resulting rubber compound.

  367 parts by weight of the obtained rubber compound was weighed, and a 14-inch roll (manufactured by Nippon Roll Co., Ltd.) (front roll surface temperature 60 ° C., rear roll surface temperature 60 ° C., front roll rotation speed 16 rpm, rear Wrapped around a roll of 18 rpm), 0.4 parts by weight of a foaming agent [OBSH manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name: Neoselbon N # 1000M] is added, and the foaming agent on the roll bank is a compound (I). After measuring the time until it was absorbed into the product, 0.5 parts by weight of sulfur, 2-mercaptobenzothiazole [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller M] 1.5 parts by weight, dibenzothia Zildisulfide [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller DM] 0.5 part by weight, zinc dibutyldithiocarbamate [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller BZ] 2 weights Zinc dimethyldithiocarbamate [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller PZ] 0.5 part by weight, ethylenethiourea [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller 22C] 1 part by weight, dithiodimorpholine [Sanshin Chemical Industry Co., Ltd., trade name Sanfell R] 0.5 parts by weight, calcium oxide [Inoue Lime Industry Co., Ltd., trade name Vesta PP] 5 parts by weight were added, 14-inch open roll (Japan) Roller Co., Ltd. (roll temperature 60 ° C.) was kneaded for 7 minutes to obtain rubber compound (II). A ribbon was cut out from the roll.

The resulting rubber compound (II) was measured for Mooney viscosity (Vm) ML _{1 + 4} , Mooney scorch time (t ₅ ), specific gravity, and die swell. The results are shown in Table 2.

  A ribbon-shaped rubber compound (II) is extruded at a speed of 2.5 m / min using a single die of 2 mm in length and 25 mm in width in an extruder with an extruder head temperature of 80 ° C. Using a molding line in which a vulcanizing tank (UHF) and a hot air vulcanizing tank (HAV) were connected in series, vulcanization and foaming were performed to obtain a vulcanized molded body (III). At this time, the temperature of UHF was 200 ° C., and the output was adjusted so that the surface temperature of the extruded material was 190 ° C. at the UHF outlet. A 30 m HAV vulcanizing tank was used, and the temperature inside the layer was set to 250 ° C. The residence time in the vulcanizing tank was 5 minutes.

  With respect to the obtained vulcanized molded product (III), specific gravity, tensile strength (TB), tensile elongation at break (EB), hardness, compression set (CS), and average foamed cell diameter were measured. The results are shown in Table 2.

(Example 2)
Ethylene / propylene / 5-ethylidene-2-norbornene random copolymer rubber (A-1) 100 parts by weight, polyethylene (B-1) [Mitsui Chemicals, trade name: Mirason 68, density: 0.921 g / cm ³ , MFR (ASTM D1238, 190 ° C., 2.14 kg): 1.6 g / 10 min] 20 parts by weight, FEF grade carbon black [manufactured by Asahi Carbon Co., Ltd., trade name: Asahi # 60G] 70 parts by weight, carbon Black [Asahi Carbon Co., Ltd., trade name Asahi F-200G] 70 parts by weight, softener [Idemitsu Kosan Co., Ltd., Diana Process Oil ^TM PS-430] 100 parts by weight, stearic acid 1 part by weight, zinc white 5 parts by weight of No. 1 and 1 part by weight of an activator [made by Lion Co., Ltd., trade name: ARCARD 2HT-F] with a capacity of 1.7 liter Banbury mixer [manufactured by Kobe Co., Ltd. Tokoro made, and the mixture was kneaded in the BB-2 form mixer].

  The kneading method involves first kneading ethylene / propylene / 5-ethylidene-2-norbornene random copolymer rubber (A-1) and polyethylene (B-1) for 1 minute, and then carbon black, softener, stearic acid, Zinc white and activator were added and kneaded for 2 minutes. Thereafter, the ram was raised and cleaned, and further kneaded for 2 minutes to obtain 1390 g of a rubber compound (A). The total kneading time was 5 minutes, the kneading temperature was the temperature of the compound (A) after discharge, and measured with a thermometer, it was 184 ° C., and the kneading / mixing ratio energy was 0.4 Kw · h / kg. Met. This kneading was carried out at a filling rate of 75%, and further, two batches were kneaded according to the same procedure to obtain a total of 4170 g. The processability index was measured for the resulting rubber compound.

  367 parts by weight of the obtained rubber compound was weighed, and a 14-inch roll (manufactured by Nippon Roll Co., Ltd.) (front roll surface temperature 60 ° C., rear roll surface temperature 60 ° C., front roll rotation speed 16 rpm, rear Wrapped around a roll of 18 rpm), 0.4 parts by weight of a foaming agent [OBSH manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name: Neoselbon N # 1000M] is added, and the foaming agent on the roll bank is a compound (I). After measuring the time until it was absorbed into the product, 0.5 parts by weight of sulfur, 2-mercaptobenzothiazole [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller M] 1.5 parts by weight, dibenzothia Zildisulfide [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller DM] 0.5 part by weight, zinc dibutyldithiocarbamate [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller BZ] 2 weights Zinc dimethyldithiocarbamate [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller PZ] 0.5 part by weight, ethylenethiourea [manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller 22C] 1 part by weight, dithiodimorpholine [Sanshin Chemical Industry Co., Ltd., trade name Sanfell R] 0.5 parts by weight, calcium oxide [Inoue Lime Industry Co., Ltd., trade name Vesta PP] 5 parts by weight were added, 14-inch open roll (Japan) Roller Co., Ltd. (roll temperature 60 ° C.) was kneaded for 7 minutes to obtain a rubber compound (B). A ribbon was cut out from the roll.

The resulting rubber compound (B) was measured for Mooney viscosity (Vm) ML _{1 + 4} , Mooney scorch time (t ₅ ), specific gravity, and die swell. The results are shown in Table 2.

  The ribbon-like rubber compound (B) is extruded at a speed of 2.5 m / min using a single die of 2 mm in length and 25 mm in width in an extruder with an extruder head temperature of 80 ° C. Using a molding line in which a vulcanizing tank (UHF) and a hot air vulcanizing tank (HAV) were connected in series, vulcanization and foaming were performed to obtain a vulcanized molded body (C). At this time, the temperature of UHF was 200 ° C., and the output was adjusted so that the surface temperature of the extruded material was 190 ° C. at the UHF outlet. A 30 m HAV vulcanizing tank was used, and the temperature inside the layer was set to 250 ° C. The residence time in the vulcanizing tank was 5 minutes.

  With respect to the obtained vulcanized molded product (C), specific gravity, tensile strength (TB), tensile elongation at break (EB), hardness, compression set (CS), and average foam cell diameter were measured. The results are shown in Table 2.

(Examples 3 to 4 and Comparative Examples 1 to 11 )
The same treatment and test as in Example 2 were performed with the formulations shown in Tables 2 and 3. The results are shown in Tables 2 and 3. In Example 4, the aspect ratio of the dispersed particles of polypropylene (B-2) was 1.5. Moreover, about Comparative Examples 6-11, the water absorption of the vulcanized molded object was also measured.

＊１ ＰＰ：ブロックポリプロピレン（（株）グランドポリマー社製、グランドポリプロＪ−７０７）
＊２ 発泡剤の混練作業性：ロールバンク上の発泡剤が配合物（Ｉ）に吸収されるまでの時間
○：３０秒未満、×：３０秒以上
＊３ 無機粉体（微粉タルク；平均粒径０．４μｍ）と発泡剤［永和化成工業（株）製ＯＢＳＨ、商品名 ネオセルボンＮ＃１０００Ｍ］とを混合機（スーパーミキサー：（株）カワセ製）に投入し、１４４０ｒｐｍ×４分の条件で混合し、無機粉体と発泡剤の総計に対して１０重量％の発泡剤を担持させたもの

* 1 PP: Block polypropylene (Grand Polypro J-707, manufactured by Grand Polymer Co., Ltd.)
* 2 Kneading workability of foaming agent: Time until the foaming agent on the roll bank is absorbed by the compound (I) ○: Less than 30 seconds, x: 30 seconds or more * 3 Inorganic powder (fine powder talc; average particle 0.4 μm in diameter) and a foaming agent [OBSH manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name: Neoselbon N # 1000M] are introduced into a mixer (Super mixer: manufactured by Kawase Co., Ltd.), and the condition is 1440 rpm × 4 minutes. Mixed and supported with 10% by weight of foaming agent based on the total amount of inorganic powder and foaming agent

It is an example of the extruder with a multistage vent used in the preferable embodiment of this invention, and is a schematic explanatory drawing of the extruder with a twin-screw three-stage vent. It is a figure which shows the relationship between specific gravity and the water absorption of the vulcanization molding of Comparative Examples 6-11.

Explanation of symbols

1 Extruder with two-shaft three-stage vent 2 Rubber mixture supply section 3 Polyolefin resin supply section 4 Vent hole 5 Take-out port

Claims (25)

  Addition comprising ethylene / α-olefin / nonconjugated polyene copolymer rubber (A), polyolefin resin (B) and foaming agent (C) composed of ethylene, α-olefin having 3 to 20 carbon atoms and nonconjugated polyene This is a vulcanizable rubber composition, which is a blend of a polyolefin resin (B) in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), and a polyolefin resin (B ) And a blend weight ratio [(B) / (A)] of the polyolefin resin (B) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). Is 5/95 to 50/50, the foaming agent (C) is unsupported, and the blending amount of the foaming agent (C) is an ethylene / α-olefin / nonconjugated polyene copolymer rubber (A 1) A vulcanizable rubber composition that is 0.05 to 0.4 parts by weight with respect to 0 part by weight, and the specific gravity of a vulcanized rubber product obtained by vulcanizing the rubber composition is 0.8 to 1 And / or a vulcanizable rubber composition in which the specific gravity of the rubber composition before vulcanization is 1.0 to 1.18.   The vulcanized rubber product has a hardness of 30 to 85, a specific gravity of 0.8 to 1, a tensile strength of 4 to 15 MPa, a tensile elongation at break of 100 to 800%, a compression set of 10 to 60%, and an average foam cell diameter of 1 to 500 μm. The rubber composition according to claim 1.   The blending amount of the foaming agent (C) is 0.1 to 0.4 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A). Rubber composition.   The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) has (i) a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) of 50/50 to 80 /. 20; (ii) an iodine number of 10-40; (iii) an intrinsic viscosity [η] measured in decalin at 135 ° C. of 2-7 dl / g; and (iv) a branching index of 0.5 It is -0.95, The rubber composition of any one of Claims 1-3.   The rubber composition according to claim 4, wherein the polyolefin resin (B) is an ethylene homopolymer or a crystalline ethylene / α-olefin copolymer.   The rubber composition according to claim 5, wherein the foaming agent (C) is at least one selected from the group consisting of an azo compound, a nitroso compound, a sulfonyl hydrazide compound, an azide compound, and an inorganic foaming agent.   The rubber composition according to claim 6, wherein the foaming agent (C) has an average particle size of 0.1 to 15 µm.   The specific gravity of the vulcanized rubber product is 0.8 to 1, the rubber composition before vulcanization is Vm (125 ° C.) 20 to 90, Mooney scorch time at 125 ° C. 2 to 10 minutes, specific gravity 1.0 It is -1.4, The rubber composition of any one of Claims 1-7.   The rubber composition according to any one of claims 1 to 8, wherein the rubber composition before vulcanization has a workability index of 5 to 50.   In advance, a polyolefin resin (B) is added to a rubber mixture composed of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an organic solvent, kneaded and desolvated, and the polyolefin resin (B) is obtained. The mixture can be obtained by preparing a kneaded product uniformly dispersed in the copolymer rubber (A) and then kneading the mixture with a foaming agent (C) and other additives. The rubber composition as described. Ethylene-alpha-olefin-nonconjugated polyene copolymer rubber (A), the other components of the polyolefin resin (B)及benefactor, kneading temperature 80 to 250 ° C., kneading time 20 minutes, kneading and mixing ratio Energy The rubber composition according to claim 6, which can be obtained by a method comprising a step of kneading under a condition of 0.001 to 10 Kw · h / kg.   The rubber composition according to any one of claims 1 to 11, which is used for producing a weather strip for an automobile.   Automotive weather strips, door weather strips, trunk weather strips, luggage weather strips, roof side rail weather strips, sliding door weather strips, ventilator weather strips, sliding loop panel weather strips, front window weather strips, rear window weather strips, quarters The rubber composition according to claim 12, which is a window weather strip, a lock pillar weather strip, a door glass outer weather strip, a door glass inner weather strip, a dam windshield, a glass run channel, a door mirror bracket, a seal head lamp or a seal cowl top. .   The rubber composition according to any one of claims 1 to 11, which is used for production of an automobile hose, a water supply hose or a gas hose.   The rubber composition according to claim 14, wherein the automotive hose is a brake hose, a radiator hose, a heater hose, or an air cleaner hose.   The rubber composition according to any one of claims 1 to 11, which is used for producing a building material seal part.   The rubber composition according to claim 16, wherein the building material seal part is a gasket, air tight, joint material or door stop.   The rubber composition of any one of Claims 1-11 used for manufacture of a household appliance seal part.   The rubber composition of any one of Claims 1-11 used for manufacture of the cup seal material for motor vehicles, or the sealing material for industrial machines.   20. The automobile cup / seal material is a master cylinder piston cup, wheel cylinder piston cup, constant velocity joint boot, pin boot, cast cover, piston seal, packing, O-ring, plug cap, plug boot, grommet or diaphragm. The rubber composition as described.   20. The rubber composition according to claim 19, wherein the industrial machine sealing material is a capacitor packing, an O-ring or a packing.   An ethylene / α-olefin / nonconjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a nonconjugated polyene, comprising: (i) ethylene and an α-olefin having 3 to 20 carbon atoms; The molar ratio (ethylene / α-olefin) is 50/50 to 80/20, (ii) the iodine value is 10 to 40, and (iii) the intrinsic viscosity [η] measured in decalin at 135 ° C. 2 to 7 dl / g, and (iv) an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) having a branching index of 0.5 to 0.95, an ethylene homopolymer or crystalline ethylene -At least one unsupported foaming agent selected from the group consisting of a polyolefin resin (B ') which is an α-olefin copolymer, an azo compound, a nitroso compound, a sulfonyl hydrazide compound, an azide compound and an inorganic foaming agent. (C ') is a vulcanizable rubber composition comprising a polyolefin resin (B') microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). The polyolefin resin (B ′) has an average dispersed particle size of 2 μm or less, and the polyolefin resin (B ′) and ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) The blend weight ratio [(B ′) / (A ′)] is 5/95 to 50/50, and the blending amount of the foaming agent (C ′) is ethylene / α-olefin / non-conjugated polyene copolymer rubber. (A ′) In producing a vulcanizable rubber composition of 0.05 to 0.4 parts by weight with respect to 100 parts by weight, an ethylene / α-olefin / non-conjugated polyene copolymer rubber ( A ') and rubber mixture consisting of organic solvent A polyolefin resin (B ′) was added to the mixture, kneaded and desolvated to prepare a kneaded product in which the polyolefin resin (B ′) was uniformly dispersed in the copolymer rubber (A ′). A vulcanizable rubber composition comprising blending and kneading other additives, and obtained by vulcanizing the vulcanizable rubber composition obtained by the production method A method for producing a vulcanizable rubber composition in which the specific gravity of the vulcanized rubber product is 0.8 to 1 and / or the specific gravity of the rubber composition before vulcanization is 1.0 to 1.18. An ethylene / α-olefin / nonconjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a nonconjugated polyene, comprising: (i) ethylene and an α-olefin having 3 to 20 carbon atoms; The molar ratio (ethylene / α-olefin) is 50/50 to 80/20, (ii) the iodine value is 10 to 40, and (iii) the intrinsic viscosity [η] measured in decalin at 135 ° C. 2 to 7 dl / g, and (iv) an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) having a branching index of 0.5 to 0.95, an ethylene homopolymer or crystalline ethylene -At least one unsupported foaming agent selected from the group consisting of a polyolefin resin (B ') which is an α-olefin copolymer, an azo compound, a nitroso compound, a sulfonyl hydrazide compound, an azide compound and an inorganic foaming agent. (C ') is a vulcanizable rubber composition comprising a polyolefin resin (B') microdispersed in a molten state in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′). The polyolefin resin (B ′) has an average dispersed particle size of 2 μm or less, and the polyolefin resin (B ′) and ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′) The blend weight ratio [(B ′) / (A ′)] is 5/95 to 50/50, and the blending amount of the foaming agent (C ′) is ethylene / α-olefin / non-conjugated polyene copolymer rubber. (A ′) When producing a vulcanizable rubber composition of 0.05 to 0.4 parts by weight with respect to 100 parts by weight, ethylene / α-olefin / non-conjugated polyene copolymer rubber (A ′ to), polyolefin resin (B')及forefather A vulcanizable rubber composition comprising a step of kneading other additives under conditions of a kneading temperature of 80 to 250 ° C., a kneading time of 1 to 20 minutes, and a kneading and mixing specific energy of 0.001 to 10 Kw · h / kg. A vulcanized rubber product having a specific gravity of 0.8 to 1 and / or a rubber before vulcanization obtained by vulcanizing a vulcanizable rubber composition obtained by the production method A method for producing a vulcanizable rubber composition having a specific gravity of 1.0 to 1.18.   The vulcanized rubber product has a hardness of 30 to 85, a specific gravity of 0.8 to 1, a tensile strength of 4 to 15 MPa, a tensile elongation at break of 100 to 800%, a compression set of 10 to 60%, and an average foam cell diameter of 1 to 500 μm. The production method according to claim 22 or 23.   The rubber product which can be manufactured by vulcanizing the rubber composition of any one of Claims 1-21.

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