JP2002317078A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition excellent in processing characteristics, slight in lowering of permanent compression set and mechanical strength when highly foamed, excellent in the balance of processability and the mechanical strength and useful for sponge rubber. SOLUTION: This rubber composition for sponge comprises (A) an oil extended ethylene-based copolymer, composed of ethylene, a 3-20C α-olefin and a non-conjugated polyene and containing the ethylene and the α-olefin at a molar ratio of (40/60) to (93/7) and having 10-40 iodine number of the non-conjugated polyene, in which an oil extension amount (α) to 100 pts.wt. ethylene-based copolymer is within the range of 10 to 100 pts.wt. and (B) an amorphous resin. The rubber composition contains, preferably, (A) (100+α) pts.wt. oil-extended ethylene-based copolymer and (B) 3-4 pts.wt. amorphous resin, and further, 10-150 pts.wt. filler, 0.3-10 pts.wt. vulcanizer and 1-10 pts.wt. foaming agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition having excellent mechanical strength and good processing characteristics. More specifically, the present invention relates to a rubber composition having a low compression set and high mechanical strength during high foaming. The present invention relates to a rubber composition useful for a sponge having an excellent balance.

[0002]

2. Description of the Related Art Conventionally, ethylene / α-olefin / non-conjugated diene copolymers are excellent in weather resistance, heat resistance, cold resistance, ozone resistance, etc., and are used as building materials, automobile parts, electric wire coating materials and the like. Widely used. In particular, many rubbers mainly composed of EPDM are used around doors and trunk rooms in order to impart soundproofness and waterproofness inside and outside an automobile. In recent years, however, there has been an increasing need for weight reduction and cost reduction of automotive materials due to environmental problems. If the specific gravity of sponge materials is reduced in conventional EPDM, physical properties such as mechanical strength are greatly reduced. It is.

[0003] In recent years, the applicant of the present application has disclosed in
No. 0888, in EPDM, a rubber composition obtained by mixing LDPE and an ethylene-α-olefin copolymer having a melting point of 50 ° C. or more is used, whereby low expansion stress and compression of sponge rubber obtained by highly foaming are obtained. It is proposed that the permanent set is less reduced. However, in this system, further improvements in compression set are needed. In addition, WO97 /
In Japanese Patent No. 02316, a rubber composition in which a crystalline polyolefin (polyethylene or polypropylene) resin is dispersed in a molten state in EPDM is reported. However, the polyethylene-based resin needs to be improved in compression set as described above. In addition, the polypropylene-based resin has satisfactory mechanical strength and compression set, but has poor workability when kneading a vulcanizing agent, and is not at a level that is sufficiently satisfactory from the balance between physical properties and workability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition having excellent mechanical strength and good processing characteristics by using an oil-extended ethylene copolymer and an amorphous resin. It is another object of the present invention to provide a rubber composition useful for a sponge which has a small reduction in compression set and mechanical strength at the time of high foaming and has an excellent balance between the two.

[0005]

According to the present invention, the following rubber composition is provided to achieve the above object of the present invention. (1) (A) It comprises ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene;
The molar ratio with the olefin (ethylene / α-olefin) is 40/60 to 93/7, and the non-conjugated polyene has an iodine value of 1
An oil-extended ethylene-based copolymer having an oil-extended amount (α) in the range of 10 to 100 parts by weight with respect to 100 parts by weight of an ethylene-based copolymer having 0 to 40 (hereinafter also referred to as “(A ′) ethylene-based copolymer”) (A) containing a copolymer and (B) an amorphous resin;
For the oil-extended ethylene copolymer (100 + α) parts by weight,
(B) A rubber composition containing 3 to 40 parts by weight of an amorphous resin.
Here, (A) oil-extended ethylene copolymer (100 + α)
The term "parts by weight" means the total amount of (A ') 100 parts by weight of the (A') ethylene copolymer before the oil-extending constituting the component (A) and (α) parts by weight, which is the number of extended oils added, The same applies to the following. (2) The rubber composition according to the above (1), wherein the glass transition temperature (Tg) of the amorphous resin measured by DSC (differential scanning calorimetry) is 90 to 170 ° C. (3) The rubber composition according to the above (1) or (2),
(A) 10 to 150 parts by weight of a filler and 0.3 part of a vulcanizing agent with respect to 100 parts by weight of an oil-extended ethylene copolymer (100 + α).
A rubber composition for a sponge, comprising 10 to 10 parts by weight and 1 to 10 parts by weight of a foaming agent. (4) A molded article obtained by molding the rubber composition according to any one of (1) to (3).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene copolymer (A) used in the rubber composition of the present invention comprises ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-octene.
-Decene and the like, preferably propylene, 1-
Butene, 1-hexene and 1-octene, more preferably propylene and 1-butene are used. These α-
The olefins can be used alone or as a mixture of two or more. The molar ratio of ethylene to α-olefin (ethylene / α-olefin) is 40/60 to 93 /
7, preferably in the range of 50/50 to 85/15,
More preferably, it is in the range of 60/40 to 80/20. When the molar ratio is within the above range, the balance between mechanical strength and compression set is excellent and optimal.

[0007] Non-conjugated polyenes include, for example,
5-ethylidene-2-norbornene, dicyclopentadiene, 5-propylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene,
Cyclic polyene such as 1,4-cyclohexadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4 -Hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 5,7-dimethyl-1 6,6-octadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 4-ethylidene-1 , 6-octadiene, 7-methyl-4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-nonadiene, 7-ethyl-4-ethylidene-1,6-nonadiene, 6,7 −Jimme A chain polyene having an internal unsaturated bond having 6 to 15 carbon atoms, such as tyl-4-ethylidene-1,6-octadiene and 6,7-dimethyl-4-ethylidene-1,6-nonadiene, 1,5- Hexadiene, 1,6-heptadiene, 1,7-octadiene,
Α, ω-
A diene, and preferably 5-ethylidene-2-
Norbornene, dicyclopentadiene, 5-vinyl-2
-Norbornene, 7-methyl-1,6-octadiene,
Examples thereof include 5-methyl-1,4-hexadiene, and more preferably, 5-ethylidene-2-norbornene, dicyclopentadiene, and 5-vinyl-2-norbornene. These non-conjugated polyenes can be used alone or in combination of two or more. The non-conjugated polyene has an iodine value in the range of 10 to 40, preferably 2
It is in the range of 0-35. In this case, if the iodine value is less than 10, the mechanical strength is poor, while if it exceeds 40, the rubber elasticity is impaired.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the (A ′) ethylene copolymer before oil extension is 80 to 30.
0, preferably in the range of 100-230. If the Mooney viscosity is less than 80, the mechanical strength of the obtained rubber vulcanizate tends to decrease, while if it exceeds 300, the processing properties of the obtained rubber composition are inferior.

(A ′) The ethylene copolymer can be produced by an appropriate method such as a gas phase polymerization method, a solution polymerization method, and a slurry polymerization method. These polymerization operations can be carried out in a batch system or a continuous system. In the above solution polymerization method or slurry polymerization method, an inert hydrocarbon is usually used as a reaction medium. Such inert hydrocarbon solvents include, for example, n-pentane, n-
Hexane, n-heptane, n-octane, n-decane,
aliphatic hydrocarbons such as n-dodecane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and aromatic hydrocarbons such as benzene, toluene and xylene. These hydrocarbon solvents can be used alone or in combination of two or more. Further, the raw material monomer can be used as a hydrocarbon solvent.

Examples of the polymerization catalyst used in producing the ethylene copolymer include an olefin polymerization catalyst comprising a transition metal compound selected from V, Ti, Zr and Hf and an organometallic compound. it can.
The transition metal compound and the organometallic compound can be used alone or in combination of two or more. Particularly preferred examples of such an olefin polymerization catalyst include a metallocene-based catalyst comprising a metallocene compound and an organoaluminum compound or an ionic compound which reacts with the metallocene compound to form an ionic complex, or a vanadium compound and an organoaluminum compound And a Ziegler-Natta catalyst.

The oil-extended ethylene copolymer (A) of the present invention comprises 10 to 100 parts by weight of an extender oil per 100 parts by weight of the copolymer (A ') polymerized by the above-mentioned polymerization catalyst.
Preferably 15 to 80 parts by weight, particularly preferably 20 to 5 parts by weight.
It contains 0 parts by weight. The (A) oil-extended ethylene copolymer of the present invention is prepared by adding the extender oil to the (A ') ethylene copolymer prior to the addition of other additives, preferably immediately after the completion of the polymerization for producing the (A') ethylene copolymer. ') It is added to the ethylene copolymer. By adding the extender oil immediately after the completion of the polymerization, the dispersibility of the filler such as carbon black is improved as compared with the composition containing the extender oil in the rubber compound preparation stage, and the processing characteristics are excellent. An oil-extended rubber composition can be obtained. The operation of adding the extender oil in the present invention can be performed by, for example, a melt-kneading method or a melt-mixing method, but is preferably a melt-mixing method. As the extender oil in the present invention, a paraffin-based process oil is preferable. Extending oils can be used alone or in combination of two or more.

The (B) amorphous resin used in the present invention is preferably a glass transition point (T) measured by DSC.
g) is in the range of 70 to 170 ° C, more preferably in the range of 90 to 130 ° C. Specific examples include polystyrene, acrylonitrile-styrene copolymer, AES resin, and polycycloolefin. Preferably, polystyrene, acrylonitrile-styrene copolymer, and AES resin are used. These amorphous resins (B) can be used alone or in combination of two or more. (B) The amorphous resin is added to the (A) oil-extended ethylene-based copolymer (100 + α) parts by weight,
It is used in a proportion of ４０40 parts by weight, preferably 5-30 parts by weight, more preferably 10-25 parts by weight. If the amount is less than 3 parts by weight, the mechanical strength is inferior, while if it exceeds 40 parts by weight, the processing performance deteriorates and the compression set deteriorates.

Next, the filler used in the present invention will be described. As the filler, for example, SRF, FE
Carbon blacks such as F, HAF, ISAF, SAF, FT, and MT; white carbon, fine particle magnesium silicate, calcium carbonate, magnesium carbonate, clay,
And inorganic fillers such as talc. These fillers can be used alone or in combination of two or more. The amount of the filler is usually 10 to 1 part by weight with respect to (A) the oil-extended ethylene copolymer (100 + α) part by weight.
It is 50 parts by weight, preferably 50 to 140 parts by weight.

Next, the vulcanizing agent used in the present invention and / or
Alternatively, a crosslinking agent will be described. As the vulcanizing agent,
For example, sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium, and tellurium; sulfur-containing organic compounds such as morpholine disulfide, alkylphenol disulfide, thiuram disulfides, and dithiocarbamate; Is mentioned. These vulcanizing agents can be used alone or in combination of two or more. The compounding amount of the vulcanizing agent is usually based on (A) oil-extended ethylene copolymer (100 + α) parts by weight.
It is 0.3 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

[0015] A vulcanization accelerator can be used in combination with the vulcanizing agent. Such vulcanization accelerators include, for example, aldehyde ammonias such as hexamethylenetetramine; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, o-trilupiguanide; thiocarbanilide, di (o-tolyl) ) Thioureas such as thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, 2- (2,2) Thiazoles such as 4-dinitrophenyl) -mercaptobenzothiazole and (N, N'-diethylthiocarbamoylthio) benzothiazole; N-tert-butyl-2-benzothiazylsulfenamide, N, N'-dicyclohexyl Le 2-benzothiazyl sulfenamide, N, N'-diisopropyl-2-benzothiazyl sulfenamide,
Sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide; thiurams such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide; Zinc dimethylthiocarbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate, iron dimethylthiocarbamate, etc. Carbamates; xanthates such as zinc butylthioxanthate; and the like. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator is usually from 0.1 to 100 parts by weight of (A) the oil-extended ethylene copolymer (100 + α).
20 parts by weight, preferably 0.2 to 10 parts by weight.

[0016] In addition to the above vulcanizing agent and vulcanization accelerator, a vulcanization accelerating aid can be added as required. Examples of such vulcanization accelerators include metal oxides such as magnesium oxide, zinc white, litharge, rhododendron, and lead white, stearic acid, oleic acid, and organic acids such as zinc stearate. Particularly preferred are zinc white and stearic acid. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerating auxiliary is (A) the oil-extended ethylene copolymer (10
0 to α) parts by weight, usually 0.5 to 20 parts by weight.

The crosslinking agent is, for example, 1,1
Ditertiary butylperoxy-3,3,5-trimethylcyclohexane, ditertiary butyl peroxide, dicumyl peroxide, tertiary butylcumyl peroxide, 2,5-dimethyl-2,5-di (tertiary butylperoxy) hexane, 1 And organic peroxides such as 3,3-bis (tert-butylperoxy-isopropyl) benzene. These crosslinking agents can be used alone or in combination of two or more. The compounding amount of the crosslinking agent is usually 0.1 part by weight with respect to (A) the oil-extended ethylene copolymer (100 + α) parts by weight.
To 15 parts by weight, preferably 0.5 to 10 parts by weight.

Further, a crosslinking assistant can be used together with the above-mentioned crosslinking agent. Examples of such a crosslinking assistant include sulfur, sulfur compounds such as dipentamethylenethiuram tetrasulfide; ethylene di (meth) acrylate;
Polyfunctional monomers such as polyethylene di (meth) acrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, toluylene bismaleimide; p-quinone oxime, p,
Oxime compounds such as p'-benzoylquinone oxime. These crosslinking assistants can be used alone or in combination of two or more. The compounding amount of the crosslinking assistant is (A) the oil-extended ethylene copolymer (100+
α) It is usually 0.5 to 20 parts by weight with respect to parts by weight.

The foaming agents used in the present invention include, for example, inorganic foaming agents such as ammonium carbonate, sodium bicarbonate and anhydrous sodium nitrate; dinitropentamethylenetetramine, N, N'-dimethyl-N, N'-diamine. Nitrosoterephthalamide, benzenesulfonyl hydrazide,
Organic foaming agents such as p, p'-oxybis (benzenesulfonyl hydrazide), 3,3'-disulfone hydrazide diphenyl sulfone, azoisobutyronitrile, and azobisformamide. Further, together with these foaming agents, foaming assistants such as urea-based, organic acid-based, and metal salt-based may be used in combination. These foaming agents and foaming aids are
Each can be used alone or in combination of two or more. The compounding amount of the foaming agent is appropriately determined according to the desired foaming density, but is usually 1 to 10 parts by weight, preferably 1 to 10 parts by weight based on (A) the oil-extended ethylene copolymer (100 + α) parts by weight. ８8 parts by weight.

The rubber composition of the present invention may optionally contain various other additives such as a softener, a plasticizer, a lubricant, a tackifier, an antioxidant, and an ultraviolet absorber.

Examples of the softening agent used in the present invention include process oils such as aromatic oils, naphthenic oils and paraffin oils which are usually used for rubber; vegetable oils such as coconut oil; synthetic oils such as alkylbenzene oils. Is mentioned. Of these, process oils are preferred, and paraffin oil is particularly preferred. The softener is
They can be used alone or in combination of two or more. The amount of the softening agent is usually 10 to 130 parts by weight, preferably 20 to 100 parts by weight, based on (A) the oil-extended ethylene copolymer (100 + α) parts by weight.

Further, the rubber composition of the present invention contains butyl rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer as long as the object of the present invention is not impaired. One or more other rubbers such as coalesced and other types of ethylene / α-olefin / non-conjugated diene copolymers may be used in combination.

When the rubber composition of the present invention is used for a sponge, the above components (A) and (B), a filler, a vulcanizing agent,
The total number of parts by weight of the rubber composition including the foaming agent and other rubber used as needed is in the range of 200 to 450 parts by weight based on 100 parts by weight of the (A ′) ethylene copolymer. Preferably it is in the range of 230 to 340 parts by weight. If the total number of parts by weight of the rubber composition is less than the above range, processability is poor, while if it is more than the above range, compression set and mechanical strength at low specific gravity are poor.

In preparing the rubber composition of the present invention, a conventionally known kneading machine, extruder, vulcanizing apparatus and the like can be used. (A) As a compounding method of a vulcanizing agent and / or a crosslinking agent, a filler, a softening agent, a foaming agent and the like mixed together with the oil-extended ethylene copolymer, for example, the components (A) and (B)
After melting and blending at 220 to 220 ° C., preferably 100 to 200 ° C., using a Banbury mixer or the like, blending a filler, a softener and the like, and then using a roll or the like, a vulcanizing agent and / or a crosslinking agent, foaming Examples include a method of adding an agent and the like, but the method is not limited thereto. Next, vulcanization and foaming by raising the temperature by placing the rubber composition of the present invention in a mold, or using an extruder, for example, by a method provided for the production of ordinary vulcanized rubber. After vulcanizing and foaming by heating in a vulcanizing tank after molding into an arbitrary shape, a vulcanized sponge rubber can be produced. The vulcanization / foaming conditions in this case are 180 to 300 ° C. for 1 to 5 minutes. The specific gravity of the obtained sponge rubber is usually 0.3 to 0.7 Mg / m ³ ,
Preferably, it is about 0.4 to 0.6 Mg / m ³ . Examples of the molded article obtained from the rubber composition of the present invention obtained in this manner include weather strips, building materials, and outer cover materials for protectors. The rubber composition (for sponge) of the present invention can be suitably used for sponge products for automobiles and various uses mainly for sponges for building materials.

[0025]

The embodiments of the present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these embodiments. The parts in the examples are on a weight basis unless otherwise specified.

The measurement and evaluation in the examples and comparative examples were carried out by the following methods. (A) α-Olefin content (mol%) It was measured by an infrared absorption spectrum method. However, the content (mol%) of the ethylene unit and the α-olefin unit in each of Examples and Comparative Examples is a value when the total amount of these units is 100 mol%. (Ii) Iodine value It was measured by an infrared absorption spectrum method. (C) Processing characteristics The degree of cohesion of the compounded rubber compound when the Banbury mixer is discharged, and the quality of the winding property when kneading the rolls are evaluated.
It was rated on a scale. The contents are as follows. ◎: Best ○: Good △: Acceptable ×: Poor

(D) Mooney viscosity (ML _{1 +} 4,100 ° C)
(Polymer MV) It was measured in accordance with JIS K6300 under the conditions of a measurement temperature of 100 ° C., a preheating of 1 minute, and a measurement of 4 minutes. (E) Glass transition temperature Tg Using a 910 type differential scanning calorimeter manufactured by Dupont Instruments (currently TIA Instruments),
The sample was heated to 180 ° C., then cooled at a rate of 10 ° C./min to −90 ° C., and measured while heating at a rate of 20 ° C./min. (F) Mooney scorch test Based on JIS K6300. (G) Sponge density The volume was calculated from the weight of the test piece in air and the weight in water. (H) Tensile test A tubular sponge with a table was cut open in the length direction, and a test piece was punched out from the tubular portion with a No. 2 dumbbell.
According to JIS K6251, at a measurement temperature of 23 ° C., 100% elongation stress M ₁₀₀ (MPa), tensile strength T
_B (MPa) and pull elongation at break E _B (%) was measured.
However, the pulling speed is 200 mm / min. (I) Compression set A tube-shaped sponge with a base having a substantially circular shape whose longitudinal dimension (a) was measured was compressed 50% in the longitudinal direction, and was heat-treated in an oven at 70 ° C for 22 hours, and then at room temperature. After standing for 30 minutes, the dimension (b) in the vertical direction was measured, and the strain was calculated by the following formula. Compression set (%) = 100 × (ba) /a×0.5

Examples 1-3 (Preparation and Evaluation of Rubber Composition) Of the components shown in Table 2, oil-extended ethylene copolymer rubber (A
-1) The non-crystalline resin was kneaded for 10 minutes at a rotation speed of 45 rpm and a set temperature of 160 ° C. using a kneader having a content of 3 L to obtain a compound (i). Next, in the compound (i), each component except for the vulcanizing agent component from the components shown in Table 2 was added to a lab size Banbury mixer (content: 1,700).
(Milliliter), and kneaded at 130 rpm for 60 seconds at a rotation speed of 60 rpm to obtain a compound (ii). Next, the remaining vulcanizing agent components shown in Table 2 were added to compound (ii), and kneaded with a 10-inch roll maintained at 80 ° C. for 5 minutes to obtain compound (iii). Unvulcanized rubber properties were evaluated using compound (iii). Next, this compound (iii) was molded using a 40 mm size extruder set at 80 to 60 ° C. and had an outer diameter of 12 m.
m, an inner diameter of 9 mm, and an unvulcanized rubber tube (iv) having a thickness of 1.5 mm were obtained. Next, this unvulcanized rubber tube (i
v) was vulcanized by passing through a hot air vulcanization tank set at 230 ° C. to obtain a vulcanized sponge rubber tube (v). The sponge rubber properties were evaluated using a vulcanized sponge rubber tube (v). Table 3 shows the evaluation results.

Comparative Examples 1 to 4 (Preparation and Evaluation of Rubber Composition) Rubber compositions were prepared and evaluated in the same manner as in the preparation and evaluation of the rubber compositions of Examples 1 to 3 described above. Table 3 shows the evaluation results.

Each composition used in the formulation is as follows. Oil-extended copolymer rubber A-1 See Table 1 Oil-extended copolymer rubber A-2 See Table 1 Non-oil-extended copolymer rubber B-1 See Table 1 Non-oil-extended copolymer rubber B-2 See Table 1 Non-oil-extended copolymer Polymerized rubber B-3 See Table 1 Polystyrene G120K (glass transition temperature = 99 ° C) manufactured by Nippon Polystyrene Co., Ltd. Carbon black manufactured by Asahi Carbon Co., Ltd. Asahi # 50HG softener PS-430 manufactured by Idemitsu Kosan Co., Ltd. Section Calcium Maruo Calcium Co., Ltd. Super S Polyethylene Glycol Toho Chemical Co., Ltd. PEG # 4000 Zinc Oxide Shodo Chemical Co., Ltd. Zinc Flower Fatty Acid Kao Co., Ltd. Lunac S-30 Processing Aid Schill & Seilacher Struct Toll WB 212 Anti-aging agent Sumitomo Chemical Co., Ltd. Sumilizer GM vulcanization system; vulcanization accelerator ZnMDC Ouchi Shinko Chemical Co., Ltd. Noxeller PZ vulcanization promotion Promoter ZnMBT Noxeller MZ vulcanization accelerator MBTS manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Noxeller DM vulcanization accelerator TeEDC manufactured by Ouchi Shinko Chemical Industry Co., Ltd. NEOSELLBON N1000SW Hygroscopic agent manufactured by Kasei Kogyo Co., Ltd. Vesta PP manufactured by Inoue Lime Industry Co., Ltd.

From the results shown in Table 3, it can be seen that the rubber composition of Example 1 using the oil-extended ethylene copolymer rubber (A-1) has the same molecular weight as the non-oil-extended ethylene copolymer rubber (A-1). B
It is superior in unity at the time of discharging the Banbury mixer as compared with Comparative Example 1 using -1). Furthermore, Example 1 using the oil-extended ethylene copolymer rubber (A-1) is Comparative Example 2 and Comparative Example using the normal non-oil-extended ethylene copolymer rubber (B-2, B-3). As compared with the rubber composition of No. 3, it has excellent mechanical strength and also has excellent compression set. Further, Example 2 using an oil-extended ethylene copolymer rubber (A-2) having an increased oil-extended amount and a high molecular weight is particularly excellent in mechanical strength and compression set. In Comparative Example 4 in which an ordinary ethylene-based copolymer rubber was used and the amount of the added resin was increased, the elongation stress was increased, but the processing characteristics were poor, and the compression set was further deteriorated.
In Example 3, in which an oil-extended ethylene-based copolymer rubber was used and a large amount of a softener was added, the processing characteristics were excellent while maintaining the mechanical strength at a high level.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

The vulcanizates of the rubber composition of the present invention are excellent in processing properties, mechanical strength and compression set. Therefore, the rubber composition useful for the sponge of the present invention has a high degree of properties as a material for a sponge part of an automobile or a sponge part for a building material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/36 C08K 5/36 C08L 91/00 C08L 91/00 101/00 101/00 (72) Inventor Mamoru Hasegawa 2--11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) The inventor Takashi Kawada 2-11-24 Tsukiji 2-chome, Chuo-ku, Tokyo JSR Co., Ltd. F-term (reference) 4F071 AA14 AA22 AA34 AA71 AA77 AB04 AB06 AB13 AB21 AC12 AE01 AE02 AE03 AF14 AF18 AH03 AH09 AH11 AH12 BA01 BB06 4F074 AA17A AA25A AA32A AA33D AC03 AC11 AC26 AC32 AD13 AD14 AG01 AG20 BA03 BA04 BA13 BA03 BA05 BB01 BB01 DA05 BN07Y DA036 DA047 DA067 DD047 DE236 DE248 DF038 DJ006 DJ036 DJ046 EN048 EN078 EQ018 EQ028 EV047 EV137 FD016 FD147 FD158 FD328 GL 00 GQ01

Claims (4)

[Claims] (A) An ethylene-α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene having a molar ratio of ethylene / α-olefin (ethylene / α-olefin) of 40/60 to 93 / 7. An oil-extended ethylene-based copolymer having an oil-extended amount (α) in the range of 10 to 100 parts by weight with respect to 100 parts by weight of an ethylene-based copolymer whose non-conjugated polyene has an iodine value of 10 to 40, and (B) A rubber composition comprising an amorphous resin and (B) 3 to 40 parts by weight of the amorphous resin with respect to (A) the oil-extended ethylene copolymer (100 + α) part by weight. 2. The amorphous resin has a glass transition temperature (Tg) of 70 to 1 measured by DSC (differential scanning calorimeter).
The rubber composition according to claim 1, which is at 70C. 3. The rubber composition according to claim 1 or 2,
(A) 10 to 150 parts by weight of a filler and 0.3 part of a vulcanizing agent with respect to 100 parts by weight of an oil-extended ethylene copolymer (100 + α).
A rubber composition for a sponge, comprising 10 to 10 parts by weight and 1 to 10 parts by weight of a foaming agent. 4. A molded article obtained by molding the rubber composition according to claim 1.