JP2002256121A - Vulcanizable rubber composition and sponge rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vulcanizable rubber composition which is excellent in storage stability and suitable for producing a foamed molded article. SOLUTION: This composition is based on an ethylene/α-olefin/nonconjugated polyene copolymer rubber (EPDM) and adjusted so that the Mooney viscosity of an unvulcanized molded rubber article prepared from the composition changes within a range of from 0 to +30 when stored in an atmosphere of 40 deg.C for 3 days. EPDM in an amount of 100 pts.wt. may be compounded with X pts.wt. zinc oxide having a specified specific surface area S (m<2> /g) and optionally compounded polyethylene glycol and/or an aliphatic ammonium in an amount of Y pts.wt. so that the relation: 10<=S.X.(1+Y)<=150 is satisfied. When EPDM is compounded with a vulcanization accelerator having an S-S bond or bonds, the amount of the accelerator (Z pts.wt.) and the number of S-S bonds (n) may satisfy the relation: Z.n<=5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vulcanizable rubber composition having excellent storage stability and a sponge rubber obtained therefrom.

[0002]

BACKGROUND OF THE INVENTION Ethylene / α-olefin copolymers and ethylene / α-olefin / diene copolymers do not have unsaturated bonds in the molecular main chain, and therefore have better weather resistance than diene rubbers. , And has excellent physical properties such as heat resistance and ozone resistance. Taking advantage of this property, the copolymer has been widely used as rubber products such as automobile industrial parts, industrial rubber products, electric insulating materials, civil engineering building materials, and rubber cloth. For example, among automotive industrial parts, it is suitably used for a foam molded article such as a weather strip sponge.

[0003] The sponge rubber is required to have particularly good designability and rubber elasticity depending on its use.
Conventionally, in such a case, a prescription for changing the type and composition of the rubber has been taken. However, as an example, when a formulation that increases the amount of the vulcanizing agent is taken, the compound may scorch during storage, or the vulcanizing agent may bloom on the product surface and reduce the design of the product, There has been a need for a rubber composition for producing a foam molded article having excellent scorch stability.

[0004]

Accordingly, an object of the present invention is to provide a vulcanizable rubber composition having excellent storage stability. Another object of the present invention is to provide a vulcanizable rubber composition suitable for producing a foam molded article. It is a further object of the present invention to provide a sponge rubber produced from such a composition, which has good appearance and excellent rubber elasticity.

[0005]

That is, the present invention relates to a composition containing an ethylene / α-olefin / non-conjugated polyene copolymer, wherein the composition has a roll temperature of 60%.
An unvulcanized rubber molded article formed by kneading for 15 minutes using an 8-inch open roll having a roll gap of 1.5 mm and a roll gap of 1.5 mm has a Mooney viscosity change of 0% while being kept in an atmosphere of 40 ° C. for 3 days. To +30 vulcanizable rubber compositions.

A composition having such storage stability has a specific surface area of S (m ² / g) based on 100 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer.
Is contained in X parts by weight of zinc oxide, and Y parts by weight of polyethylene glycol and / or aliphatic ammonium added as necessary, and the following formula (S) is present between S, X and Y. A composition satisfying the relationship of 1) is preferable. 10 ≦ (S) · (X) · {1+ (Y)} ≦ 150 (1)

The above-mentioned rubber composition having storage stability is described in the following (1) to 100 parts by weight of ethylene / α-olefin / non-conjugated polyene copolymer.
(8) at least one vulcanization accelerator selected from the group consisting of 0.1 to 20 parts by weight, (1) thiazole compound (2) guanidine compound (3) aldehyde amine compound ( 4) Imidazoline-based compound (5) Thiourea-based compound (6) Thiuram-based compound (7) Thiocarbamate-based compound (8) Xanthate-based compound Sulfur-sulfur bond in the chemical vulcanization accelerator When a compound having the following formula (2) is contained, the relationship represented by the following formula (2) is established between the content Z part by weight of the compound and the number of sulfur-sulfur bonds n per molecule present in the compound. Compositions which hold true are also preferred. (Z) · (n) ≦ 0.5 (2)

Further, the above-mentioned rubber composition having storage stability is based on (1) based on 100 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer.
At least one of 0.1 to 20 parts by weight of vulcanization accelerator selected from the group consisting of (8), specific surface area S ^(m 2 /
g) zinc oxide, and Y parts by weight of optionally added polyethylene glycol and / or aliphatic ammonium, and between the S, X, and Y, A composition that satisfies the relationship of the formulas (1) and (2) is also preferable.

[0009] The present invention also relates to a sponge rubber obtained by subjecting the vulcanizable rubber composition to crosslinking foam molding.
It has a smooth sponge skin, good design properties and high rubber elasticity.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The vulcanizable rubber composition according to the present invention is a composition having excellent storage stability containing an ethylene / α-olefin / non-conjugated polyene copolymer,
In the present invention, the change in the Mooney viscosity is expressed as an index indicating the storage stability. First, the composition is kneaded for 15 minutes using an 8-inch open roll having a roll temperature of 60 ° C. and a roll gap of 1.5 mm to form an unvulcanized rubber molded body. The molded body is kept in a temperature atmosphere of 40 ° C. for 3 days, and before and after that, the Mooney viscosity (Vm: 125 ° C.) is measured, and the change is determined.

The vulcanizable rubber composition of the present invention has a Mooney viscosity change of 0 to +30, preferably 0 to +20, measured after molding into an unvulcanized molded article under the above conditions.
In the range. When the unvulcanized molded product is within the range of the change in the Mooney viscosity, the rubber composition has long-term storage stability, and a product molded therefrom has a good appearance and high rubber elasticity. Have.

Next, the components that actually constitute the composition, the specific composition of the composition, and the sponge rubber obtained by crosslinking and foaming the composition will be described.

[0013] Co-Polymerization body available ethylene-alpha-olefin-nonconjugated polyene copolymer, ethylene, rubber alpha-olefins having 3 to 20 carbon atoms, and a non-conjugated polyene prepared by random copolymerization Ternary copolymer.

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 and 1-eicosene can be mentioned, and they can be used alone or in combination of two or more. Among them, α-olefins having 3 to 10 carbon atoms, especially propylene,
-Butene, 4-methyl-1-pentene, 1-hexene,
1-octene is preferably used.

The proportion (molar ratio) of ethylene and α-olefin in the copolymer is 60/40 to 80/20, preferably 62/40, expressed as ethylene / α-olefin.
38-79 / 21, particularly preferably 65 / 35-78 /
22. Within this range, a copolymer exhibiting good rubber elasticity can be obtained.

As the non-conjugated polyene, specifically,
1,4 hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-
Chain non-conjugated dienes such as 1,4-hexadiene, 4,5-diethyl-1,4-hexadiene, 7-methyl-1,6-octadiene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene -2-norbornene, 5-isopropylidene-2-norbornene,
Cyclic non-conjugated dienes such as 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene and 5-vinyl-2-norbornene; 2,3-diisopropylidene-5-norbornene; And trienes such as ethylidene-3-isopropylidene-5-norbornene and 2-propenyl-2,2-norbornadiene. They can be used alone or in combination of two or more.

When the content of the non-conjugated polyene in the copolymer is represented by an iodine value, the iodine value is 10 to 50, preferably 15 to 40, more preferably 18 to 35, and particularly preferably 20 to 30. Is desirable. When the iodine value is in this range, an appropriate effective network chain density can be obtained, so that the compression set is small and the resistance to environmental degradation is good.

Such a copolymer is one or two of
More than one species can be used in combination, and modified products thereof can also be used. In addition, this copolymer is
"Polymer manufacturing process" (published by the Industrial Research Institute, Inc.)
P. 309-330) and the like.

[0019] The acid of zinc oxide zinc, generally zinc oxide, activated zinc white, composite zinc oxide,
It is commercially available under the names of surface-treated zinc white, composite activated zinc white, and the like, and any of them can be used in the present invention. The specific surface area is preferably in the range of 1 to 30 (m ² / g), and particularly in the case of zinc white, 1 to 5 (m ² / g).
g) is 15 to 30 (m ² / g) when activated zinc white
Is desirable. The average particle size is preferably in the range of 0.1 to 100 μm.

This zinc oxide is usually used in an amount of 2 per 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.
10 to 10 parts by weight, preferably 5 to 10 parts by weight. Such zinc oxide acts as a vulcanization accelerator at the time of molding, and when a fatty acid is present, forms a complex therewith to increase the activity of the vulcanization accelerator and improve the vulcanization rate. When the specific surface area and the average particle diameter are within the above-mentioned ranges, a high activation effect is exhibited. This zinc oxide also acts as a bulking agent.

In the present invention, as a compounding agent which is added in combination with the above-mentioned zinc oxide and does not impair the vulcanizing effect, a metal, a metal oxide or another metal compound can be used. As the metal, for example, lead,
Iron, aluminum, and zinc are preferred, and powder having an average particle size of 0.1 to 100 μm is particularly preferred. As metal oxides, lead oxide, lead suboxide, magnesium oxide, surface treated magnesium oxide, lead red, white lead, zinc white complex,
Antimony trioxide, diantimony pentoxide, titanium oxide,
Iron oxide (Fe ₂ O ₃ ; brown), chromium oxide (Cr
₂ O ₃ ; green). Examples of the metal compound include the following examples. In addition,
Both of these metal oxides and metal compounds are preferably powders having an average particle size in the range of 0.1 to 10 μm.

(1) Zinc stearate, calcium stearate, aluminum stearate, lead stearate, cadmium stearate, barium stearate,
Magnesium stearate, lithium stearate, 1
Magnesium 2-hydroxystearate, calcium 12-hydroxystearate, barium 12-hydroxystearate, zinc 12-hydroxystearate, dibasic lead stearate, calcium laurate,
Fatty acid metal salts such as barium laurate, zinc laurate, cadmium laurate, barium ricinoleate

(2) Zinc 2-ethylhexoate, 2-
Lead ethylhexoate, dibasic lead phthalate, tribasic lead maleate, tribasic lead sulfate, modified tribasic lead sulfate,
Tribasic lead sulfite, basic lead sulfite, monobasic lead sulfate,
Dibasic lead phosphite, barium sulfate, calcium hydroxide, zinc dimethacrylate, magnesium dimethacrylate, aluminum hydroxide, magnesium hydroxide, zinc borate

These metals, metal oxides or metal compounds are used in an amount of 2 to 20 parts by weight, preferably 3 to 15 parts by weight, and more preferably 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer. Preferably, it is added in a ratio of 3 to 10 parts by weight. When it is blended in this range, a rubber composition excellent in storage stability or a foam molded article excellent in storage stability can be obtained.

Polyethylene glycol, aliphatic ammonium
In the present invention, polyethylene glycol and / or aliphatic ammonium may be used as a preferred activator, which, like zinc oxide, enhances the activity of a vulcanization accelerator and improves the vulcanization rate. Can be. Polyethylene glycol and aliphatic ammonium may be used alone or in combination. Further, these activators do not necessarily need to be added and blended, but when they are added, the blending amount is ethylene · α-
0.05 to 3.0 parts by weight, preferably 0.1 to 1.0 parts by weight, per 100 parts by weight of the olefin / non-conjugated polyene copolymer.
A range of 5 parts by weight is desirable.

Polyethylene glycol is a ring-opened polymer of ethylene oxide having a molecular weight of preferably 1,000 to 20,000, more preferably 2,000.
Desirably, up to 10,000 polymers. As the aliphatic ammonium, dialkyldimethylammonium chloride can be preferably used. For example, products marketed by Lion Akzo Co. under the trade names of ARKARD 2HT, ARKARD 2C, and ARKARD 2O can be used. .

In the present invention, in addition to polyethylene glycol and / or aliphatic ammonium, a substance generally incorporated as an activator can be used in combination.
Such activators include (1) and (2)
Can be mentioned. They are usually blended at a ratio of 0.2 to 10 parts by weight, preferably 0.3 to 8 parts by weight, per 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.

(1) Di-n-butylamine, dicyclohexylamine, monoethanolamine, diethanolamine, triethanolamine, dibenzylamine, and others are sold under the trade names of Acting B and Acting SL (both are products of Yoshitomi Pharmaceutical Co., Ltd.). Organic amines

(2) Lecithin, triallyl-trimellitate, zinc carboxylate sold under the trade name of Struktol activator (product of Schill & Seilacher), Stru
ktolIB531 and Struktol FA541 (Schill & Seilacher
Amine-based activator sold under the trade name of), zinc peroxide preparation octadecyl trimethylammonium bromide, synthetic hydrotalcite

[0030] As the vulcanization promoting agent vulcanization accelerator, it is then referred compounds among (1) to (8) using at least one. (1) thiazole compound (2) guanidine compound (3) aldehyde amine compound (4) imidazoline compound (5) thiourea compound (6) thiuram compound (7) thiocarbamate compound (8) xanthate Compound

The vulcanization accelerator is used in an amount of 0.1 to 20, preferably 0.2 to 10, and more preferably 0.5 to 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer. ５5 parts by weight.

Next, specific examples of each compound will be shown. (1) Thiazole-based compound: N-cyclohexyl-2-benzothiazolsulfenamide, N-oxydiethylene-2
-Benzothiazolsulfenamide, N, N'-diisopropyl-2-benzothiazolsulfenamide,
2-mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2-
(2,6-diethyl-4-morpholinothio) benzothiazole, dibenzothiazyl-disulfide, 2-
(4'-morpholinodithio) benzothiazole.

(2) Guanidine compounds: diphenylguanidine, triphenylguanidine, diorthotolylguanidine, N, N'-diphenylguanidine. (3) aldehyde amine compound: acetaldehyde-
Aniline condensate, butyraldehyde-aniline condensate.

(4) Imidazoline compound: 2-mercaptoimidazoline. (5) Thiourea compounds: diethylthiourea, dibutylthiourea, ethylenethiourea. (6) Thiuram compounds: tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide.

(7) Dithiocarbamate compounds: zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, tellurium diethyldithiocarbamate, zinc dibutyldithiocarbamate and zinc dimethylcarbamate. (8) Xanthate compounds: zinc dibutylxanthate.

The vulcanizable rubber composition wherein the conditions, that is, as a preferred embodiment of the vulcanizable rubber composition satisfying the variation of the Mooney viscosity, described below three be mentioned specific composition Can be.

The first composition is at least composed of an ethylene / α-olefin / non-conjugated polyene copolymer, zinc oxide, and optionally added polyethylene glycol and / or aliphatic ammonium. .

The composition was prepared by adding X parts by weight of zinc oxide to 100 parts by weight of the copolymer,
And / or aliphatic ammonium, when Y parts by weight are mixed, the specific surface area S of X, Y and zinc oxide
(M ² / g) and the following equation (1). 10 ≦ (S) · (X) · {1+ (Y)} ≦ 150 (1) Preferably, 13 ≦ (S) · (X) · {1+ (Y)} ≦ 130 ...・ ・ (1) '

A composition satisfying such a relationship is excellent in storage stability, and hardly generates scorch even after long-term storage. From this composition, a crosslinked foam having a density suitable for use at a moderate vulcanization rate, that is, a sponge rubber, is obtained, and has a good rubber elasticity and a smooth sponge skin.

The second composition comprises an ethylene / α-olefin / non-conjugated polyene copolymer and the above-mentioned (1) to (4).
And at least one vulcanization accelerator selected from the group consisting of (8). In this composition, the above-mentioned vulcanization accelerator was added in an amount of 0.1 to 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.
-20 parts by weight.

When the vulcanization accelerator contains at least one compound having a sulfur-sulfur bond in the chemical structural formula, the content Z based on 100 parts by weight of the copolymer is used.
Parts by weight and sulfur per molecule present in the compound
The following equation (2) is established between the number of sulfur bonds and n. (Z) · (n) ≦ 0.5 (2) Preferably, 0.001 ≦ (Z) · (n) ≦ 0.5 ... (2) '

When two or more compounds having a sulfur-sulfur bond are added and blended,
(N) The value of｝ may be calculated, and the total amount may be applied to the relational expressions of (2) and (2) ′. The composition in which such a relationship is established between Z and n is excellent in storage stability and hardly generates scorch even after long-term storage.

The third composition is an ethylene / α-olefin / non-conjugated polyene copolymer, as described in (1) to (8) above.
At least one vulcanization accelerator selected from the group consisting of
It is composed of at least zinc oxide and, if necessary, polyethylene glycol and / or aliphatic ammonium. Also in this composition, the relation between zinc oxide and polyethylene glycol and / or aliphatic ammonium satisfies the relations of the above formulas (1) and (1) ′. Contains a compound having a sulfur-sulfur bond,
The relationship of the above-mentioned relational formulas (2) and (2) ′ relating to the compound is also satisfied.

Such a vulcanizable rubber composition usually contains a compounding agent such as a vulcanizing agent, a vulcanizing aid, a carbon black, a softening agent, a processing aid, an antioxidant, a reinforcing agent and a filler. Is added and mixed to form a vulcanizable rubber composition, which is used for general rubber molding applications. In the case of producing a foam molded article, a foaming agent is added in addition to the above-mentioned compounding agent, and a foaming aid, a defoaming agent, and a crosslinking agent may be added as necessary. Furthermore, depending on the molding method and application, heat-resistant stabilizers,
Antistatic agents, coloring agents, lubricants and the like can be blended within the scope of the present invention. Next, typical various compounding agents will be described.

<Vulcanizing Agent> As the vulcanizing agent, any of a sulfur compound and an organic peroxide can be used. Examples of the sulfur compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, and selenium dithiocarbamate. Among them, sulfur is preferable, and these sulfur compounds are
Ethylene / α-olefin / non-conjugated polyene copolymer 1
The amount is usually 0.1 to 10, preferably 0.5 to 5, more preferably 1.0 to 3.0 parts by weight based on 00 parts by weight.

As the organic peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane , 2,5-dimethyl-
2,5-di (t-butylperoxy) hexyne-3, di-t-butyl peroxide, di-t-butylperoxy-
3,3,5-trimethylcyclohexane, di-t-butyl hydroperoxide and the like. Among them, dicumyl peroxide, di-t-butyl peroxide, di-
t-Butylperoxy-3,3,5-trimethylcyclohexane is preferably used. The amount of the organic peroxide to be used is usually 3 × 10 ^{−3 to} 5 × 10 ⁻² , preferably 1 × 10 ^{−3 to} 3 × 10 per 100 g of the ethylene / α-olefin / non-conjugated polyene copolymer. A range of ^-2 mol is desirable.

<Vulcanization Aid> When an organic peroxide is used as a vulcanizing agent, it is preferable to use a vulcanization aid in combination. Examples of the vulcanization aid include sulfur; quinone dioxime compounds such as p-quinone dioxime; ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate.
(Meth) acrylate compounds such as thiol; allyl compounds such as diallyl phthalate and triallyl isocyanurate; and other maleimide compounds and divinyl benzene. Such a vulcanization aid is added at a ratio of 0.5 to 2 mol, preferably equal to 1 mol of the organic peroxide used.

<Carbon Black> Specific examples of carbon black include SRF, GPF, FEF, MA
Carbon black such as F, HAF, ISAF, SAF, FT, and MT. These carbon blacks may be subjected to a surface treatment with a silane coupling agent or the like, and the average particle size thereof is usually 10 to 100 μm.
m, preferably 20 to 80 μm, which has the effect of increasing the mechanical strength such as the tensile strength, tear strength and abrasion resistance of the rubber molded article.

The carbon black is used in a proportion of 10 to 150 parts by weight, preferably 20 to 120 parts by weight, more preferably 30 to 100 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer. Used in When the compounding amount of the carbon black is within the above range, the mechanical strength of the molded body can be increased and the weather resistance can be improved.

<Softener> The following substances can be used as a softener which acts as a rubber lubricant and enhances processability. (1) Petroleum softeners such as naphthenic process oils, aromatic process oils, lubricating oils, paraffin, liquid paraffin, petroleum asphalt, petrolatum, etc. (2) Cores such as coal tar and coal tar pitch Rutar softener (3) Fat oil softener such as castor oil, rapeseed oil, soybean oil, coconut oil, etc. (4) Tall oil (5) Waxes such as beeswax, carnauba wax and lanolin (6) Fatty acids such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate or metal salts thereof

(7) Naphthenic acid or its metallic soap (8) Pine oil, rosin or its derivative (9) Synthetic polymer substance such as terpene resin, petroleum resin, coumarone indene resin, atactic polypropylene (10) Dioctyl lid Rate, dioctyl adipate
Ester plasticizers such as dioctyl sebacate, etc. (11) Carbonate ester plasticizers such as diisododecyl carbonate (12) Others, microcrystalline wax, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid Thiocol, hydrocarbon synthetic lubricating oil, etc.

In the present invention, among these,
The mineral oil softeners (1), (2) and (9) are preferably used, and aromatic mineral oils exemplified by aromatic process oils are particularly desirable. These softeners are commercially available under the trade names such as Diana Process AC-460 (product of Idemitsu Kosan Co., Ltd.), Diana Process AC-12 (product of Idemitsu Kosan Co., Ltd.), and Esso Process Oil 110 (product of Esso Oil Co., Ltd.). It can be used for the invention.

These softeners are used in an amount of 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.
It is usually used in a proportion of 100 parts by weight or less, preferably 70 parts by weight or less. When the compounding amount of the softening agent is within the above range, the processability of the rubber composition can be improved.

<Reinforcing Material, Filler> In addition to finely divided silica, the various carbon blacks described above can be used as the reinforcing material. As the filler, light calcium carbonate, heavy calcium carbonate, talc, clay and the like are used.
These reinforcing materials and fillers are based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.
It is usually blended in a proportion of 200 parts by weight or less, preferably 150 parts by weight or less.

<Processing Aid> Processing aids used in ordinary rubber processing can be used, and examples thereof include the following compounds. That is, higher fatty acids such as ricinoleic acid, stearic acid, palmitic acid and lauric acid; barium stearate, calcium stearate,
Higher fatty acid salts such as zinc stearate; ricinoleate, stearate, palmitate,
Higher fatty acid esters such as lauric acid esters. These processing aids are usually blended in an amount of 10 parts by weight or less, preferably 1 to 5 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.

<Blowing Agent> As the blowing agent used in the foam molding, any of inorganic and organic blowing agents can be suitably used. For example, the following compounds can be exemplified. (1) Inorganic blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite

(2) Nitroso compounds such as N, N'-dinitrosoterephthalamide, N, N'-dinitrosopentamethylenetetramine (3) Azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiamino Azo compounds such as benzene and barium azodicarboxylate

(4) benzenesulfonyl hydrazide,
Sulfonyl hydrazide compounds such as toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide) and diphenylsulfone-3,3'-disulfenyl hydrazide; (5) calcium azide, 4,4'-diphenyl disulfonyl azide; Azide compounds such as p-toluenesulfonyl azide

Of these, azo compounds, sulfonyl hydrazide compounds and azide compounds are preferably used. The amount of the foaming agent is appropriately adjusted so that the specific gravity of the foam after vulcanization and foaming becomes 0.01 to 0.9.
Ethylene / α-olefin / non-conjugated polyene copolymer 1
0.5 to 30, preferably 1 to 2, with respect to 00 parts by weight.
0, more preferably 2 to 10 parts by weight.

Further, if necessary, a foaming aid may be used in combination with a foaming agent. The addition of a foaming aid is effective in controlling the decomposition temperature of the foaming agent, making the air bubbles uniform, and the like. Examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid, and oxalic acid, urea and derivatives thereof.

<Anti-aging Agent> In the present invention, excellent heat resistance and durability are exhibited without adding an anti-aging agent, but the product life can be further extended by adding an appropriate amount. Examples of the antioxidant include aromatic secondary amine stabilizers such as phenylbutylamine and N, N'-di-2-naphthyl-p-phenylenediamine; dibutylhydroxytoluene, tetrakis [methylene-3 (3,5 -Ji-
t-butyl-4-hydroxyphenyl) cinnamate]
Phenol stabilizers such as methane; bis [2-methyl-4
-(3-n-alkylthiopropionyloxy) -5-
thioether stabilizers such as [t-butylphenyl] sulfide; dithiocarbamate stabilizers such as nickel dibutyldithiocarbamate.

These anti-aging agents can be used alone or
These can be used in combination of at least one kind, and are usually 0.1 to 5, preferably 0.5 to 3, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer.
It can be blended in a ratio of parts by weight.

The vulcanizable rubber composition according to the present invention comprises:
For example, it can be prepared by the following method. That is, various compounding agents such as zinc oxide, polyethylene glycol, aliphatic ammonium, a sulfur-donating organic compound, carbon black, a softener, and a filler are added to an ethylene / α-olefin / non-conjugated polyene copolymer, and Using a mixer such as a mixer at a temperature of 80 to 170 ° C. for about 3 to
Mix and knead for 10 minutes.

Thereafter, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid,
Add a compounding agent such as a foaming agent and a foaming aid, and use a roll such as an open roll at a roll temperature of 40 to 80 ° C.
Knead for ~ 30 minutes. Then, when “dispensing”, a sheet-like rubber composition can be obtained. The vulcanizable rubber composition thus obtained can be used as it is or as a raw material in various industrial fields after vulcanization.

Sponge Rubber The above-described vulcanizable rubber composition is further blended with a foaming agent and, if necessary, a crosslinking agent, and then placed in an atmosphere at a temperature higher than the decomposition temperature of the foaming agent to produce a foam. can do. At that time, it can be made into a sponge rubber having a desired shape by placing it in a molding die or cutting it out from a sheet-like foam. Although the expansion ratio varies depending on the application, the expansion conditions are usually adjusted to 1.5 to 4 times. The sponge rubber thus obtained can be used as a product or part or as a material in a wide range of industrial fields.

[0066]

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

In Examples and Comparative Examples, Mooney viscosity (Vm: 125 ° C.) and Mooney scorch time (t5 (minute): Mooney viscosity; 125) for physical property evaluation
° C) was measured in accordance with JIS K6300 (1998).

The following rubbers and various compounding agents were used for preparing the composition. (1) Ethylene / α-olefin / non-conjugated polyene copolymer: ethylene / propylene / 5-ethylidene-2-norbornene copolymer ・ Ethylene content: 57.1% by weight, diene content: 9.5
% By weight (ethylene content + propylene content + diene content = 100
・ Iodine value: 26 ・ Intrinsic viscosity [η] measured in decalin at 135 ° C .: 2.
7 (dl / g) Mw / Mn = 5.7 Oil extension amount: 20 phr

(2) Zinc oxide: (a) Zinc oxide (manufactured by Tokyo Rika Kogyo Co., Ltd., trade name: two types of zinc oxide) Specific surface area: 1.8 (m ² / g) (b) Active zinc flower (Inoue Lime Industry Co., Ltd., trade name Meta Z102) Specific surface area: 20 (m ² / g)

(3) Polyethylene glycol: (molecular weight: 4000, manufactured by Lion Corporation, trade name: PEG # 400)
0)

(4) Carbon black: SRF-HS carbon black (Asahi Carbon Co., Ltd., trade name Asahi # 50)
HG) (5) Softener: paraffin-based process oil (manufactured by Idemitsu Kosan Co., Ltd., trade name: Diana Process Oil PS)
-430)

(6) Foaming agent: p, p'-oxybis (benzenesulfonyl hydrazide) (manufactured by Eiwa Chemical Co., Ltd.)
Product name Neoservon TM1000SW) (7) Defoaming agent: calcium oxide (manufactured by Inoue Lime Industry Co., Ltd.)
Vesta 20)

(8) Vulcanizing agent: sulfur (9) Processing aid stearic acid (manufactured by NOF Corporation)

(10) Vulcanization accelerator: (a) dipentamethylenethiuram tetrasulfide (D
PTT) (manufactured by Sanshin Chemical Industry Co., Ltd., trade name: Sansera)
TRA) (b) 2- (4'-morpholinodithio) benzothiazo-
MDB (Ouchi Shinko Chemical Industry Co., Ltd., trade name Noxera-MDB)

(C) 2-mercaptobenzothiazole (MBT) (manufactured by Sanshin Chemical Industry Co., Ltd., trade name: Sansera-M) (d) Zinc dibutyldithiocarbamate (ZnBDC) (Sanshin Chemical Industry Co., Ltd.) ), Trade name Sancera-BZ) (e) Zinc dimethylcarbamate (ZnMDC) (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sancera-PZ) (f) Tellurium diethyldithiocarbamate (TeED)
C) (Made by Sanshin Chemical Industry Co., Ltd., trade name: Sancera-TE)

(G) Ethylenethiourea (EU) (manufactured by Sanshin Chemical Industry Co., Ltd., trade name: Sunsera-22) (h) N-cyclohexylbenzothiazyl-2-sulfendamide (CBS) (Sanshin Chemical (Sancera-CM) manufactured by Kogyo Co., Ltd. (i) N, N'-diphenylguanidine (DPG) (Sancera-D manufactured by Sanshin Chemical Industry Co., Ltd.) (a) is SS (B) having three bonds in the molecule;
Has one and the other compounds do not have an SS bond.

Examples 1 to 5 Comparative Examples 1 to 6 Ethylene / propylene / 5-ethylidene-2-norbornene copolymer, processing aid, active zinc white or zinc oxide 2
The seed, carbon black, softener, and polyethylene glycol were kneaded for 5 minutes at 150 ° C. using a 2.95 liter Mixtron mixer [manufactured by Kobe Steel Ltd.].

To the kneaded material thus obtained, a vulcanizing agent, a vulcanization accelerator, a foaming agent and a defoaming agent are added, and
The mixture was kneaded for 10 minutes using an 8-inch open roll (manufactured by Nippon Koki Co., Ltd.) adjusted to 60 ° C. to prepare a rubber composition. This rubber composition was further stored at an oven temperature of 40 ° C. for 3 days to accelerate vulcanization. A physical property measurement test was performed on the obtained rubber molded body, and the results are shown in Table 1.

The common formulations in the examples and comparative examples were as follows. Copolymer rubber 120 parts by weight Processing aid 2 parts by weight Carbon black 90 parts by weight Softener 70 parts by weight Blowing agent 4 parts by weight Defoaming agent 4 parts by weight As described in Table 1.

[0080]

[Table 1]

[0081]

In the vulcanizable rubber composition according to the present invention, a specific substance having a vulcanization accelerating effect is blended in a certain range, so that physical properties excellent in storage stability and scorch stability can be obtained. Was completed. Therefore, this composition is suitable as a raw material for a usual vulcanized molded article or as a raw material for a sponge rubber formed by crosslinking and foaming, and is used for automobile industrial parts, industrial rubber products, electrical insulating materials, civil engineering building materials. And the like.

Further, in the present invention, foam molding using this rubber composition can provide a sponge rubber having smooth sponge skin while maintaining excellent design properties and high rubber elasticity. This sponge rubber is
It can be suitably used for automotive sponge parts such as weather strip sponge, construction sponge parts and the like.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08L 71/02 C08L 71/02 (72) Inventor Shinya Matsunaga 3 Chikatsukaigan, Ichihara-shi, Chiba Prefecture Mitsui Chemicals Co., Ltd. In-house (72) Inventor Masaaki Kawasaki 3 Chikusa Kaigan, Ichihara City, Chiba Prefecture Mitsui Chemicals, Inc.F-term (reference) EV168 EV328 EZ008 FD010 FD020 FD030 FD140 FD150 FD158 FD320 GT00

Claims (8)

[Claims] 1. A composition containing an ethylene / α-olefin / non-conjugated polyene copolymer, which is obtained from the composition using an 8-inch open roll having a roll temperature of 60 ° C. and a roll gap of 1.5 mm for 15 minutes. A vulcanizable rubber composition characterized in that the amount of change in Mooney viscosity during a period in which an unvulcanized rubber molded article formed by kneading is kept in an atmosphere at 40 ° C. for 3 days is 0 to +30. 2. The composition comprises X parts by weight of zinc oxide having a specific surface area of S (m ² / g) and 100 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer. It contains Y parts by weight of polyethylene glycol and / or aliphatic ammonium added as required, and the following formula (1) is established between S, X and Y. The vulcanizable rubber composition according to claim 1. 10 ≦ (S) · (X) · {1+ (Y)} ≦ 150 (1) 3. The composition according to claim 1, wherein at least one member selected from the group consisting of the following (1) to (8) is used per 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer. 0.1 to 20 parts by weight of a vulcanization accelerator, (1) a thiazole compound, (2) a guanidine compound, (3) an aldehydeamine compound, (4) an imidazoline compound, (5) a thiourea compound (6) ) Thiuram-based compound (7) Thiocarbamate-based compound (8) Xanthate-based compound When the vulcanization accelerator contains a compound having a sulfur-sulfur bond in the chemical structural formula, 2. The process according to claim 1, wherein a relationship represented by the following formula (2) is established between the content Z of the compound and the number of sulfur-sulfur bonds per molecule present in the compound. Vulcanizable rubber Narubutsu. (Z) · (n) ≦ 0.5 (2) 4. The above composition further has a specific surface area of S (m
² / g) of zinc oxide, and Y parts by weight of polyethylene glycol and / or aliphatic ammonium, which are added as needed.
The vulcanizable rubber composition according to claim 6, wherein a relationship represented by the following formula (3) is satisfied between X and Y. 10 ≦ (S) · (X) · {1+ (Y)} ≦ 150 (3) 5. A method according to claim 1, wherein said polyethylene glycol and / or aliphatic ammonium is present in an amount of 0.0
The vulcanizable rubber composition according to claim 2, wherein the rubber composition is added in an amount of 5 to 3.0 parts by weight. 6. The vulcanizable rubber composition according to claim 2, wherein the polyethylene glycol has a molecular weight of 1,000 to 20,000. 7. The vulcanizable rubber composition according to claim 2, wherein said aliphatic ammonium is dialkyldimethylammonium chloride. 8. A sponge rubber obtained by subjecting the vulcanizable rubber composition according to any one of claims 1 to 7 to crosslinking foam molding.