JPH04139219A - Crosslinked rubber composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent durability, heat resistance and ozone resistance and useful for industrial good, etc., by crosslinking a specific hydrogenated conjugated diene-based polymer consisting of styrene and butadiene. CONSTITUTION:The objective composition obtained by crosslinking a hydrogenated conjugated dine-based polymer obtained by crosslinking a polybutadiene whose contents of stylene and butadiene are 0-40wt.%, and 100-60wt.%, respectively, and having 25-70%, pref., 30-55% of vinyl binding amount or a hydrogenated conjugated diene-based polymer wherein 97-100% of the olefinic unsaturated double bonds of a styrene-butadiene copolymer are hydrogenated with a crosslinking agent system consisting of a radical generating compound such as dicumyl peroxide and a crosslinking assistant such as sulfur.

Description

[Detailed Description of the Invention] [Industrial Fields of Application] The present invention is applicable to heat resistance, mechanical strength, weather resistance, ozone resistance,
This invention relates to a crosslinked rubber composition made of a hydrogenated conjugated diene polymer that has excellent durability.

[Prior Art] Rubber compositions have the following properties: compared to other materials, rubber compositions have a low elastic modulus and are capable of large deformations, have vibration absorption performance, and have large frictional resistance. It is used in various fields to take advantage of its characteristics.

In recent years, rubber compositions used for automobile parts, electrical parts, industrial products, building materials, etc. have become less resistant to heat, weather, and ozone due to factors such as operating temperatures, harsher operating environments, and longer operating periods. There is a growing demand for improvements in performance and durability.

Among various conventional raw material rubber polymers, rubber compositions based on conjugated diene rubbers such as natural rubber, polybutadiene rubber, and styrene-butadiene rubber do not have sufficient ozone resistance, and Due to poor heat resistance,
It is not necessarily suitable for applications that are often used outdoors or applications that are exposed to high temperatures for long periods of time.

On the other hand, ethylene-propylene copolymer rubber (EPM) and ethylene-propylene-polyene copolymer rubber (EPDM), which have fewer unsaturated bonds, have better weather resistance, ozone resistance, and heat resistance than conjugated diene rubber. Therefore, it has come to be used in automobile parts, heat-resistant hoses, construction materials, etc. However, rubber compositions mainly composed of EPM or EPDM have not always had sufficient compression set resistance, mechanical strength, heat resistance, etc.

Under these circumstances, polymers in which the unsaturated double bonds of conjugated diene polymers are hydrogenated and rubber compositions thereof are being developed as polymers that improve the weather resistance and ozone resistance of conventional conjugated diene polymers. , Special Publication No. 46-35497,
Special Publication No. 47-8928, Special Publication No. 48-30351
However, it is said that the workability, strength, wear resistance, etc. are insufficient. Further, as improvements to the above hydrogenated polymers, Japanese Patent Laid-Open No. 60252643 and Japanese Patent Laid-Open No. 62
Hydrogenated polymers of polybutadiene or styrene-butadiene copolymers with specific structures and compositions thereof are disclosed in Japanese Patent Application Laid-open No. 283105, Japanese Patent Application Laid-Open No. 63-41547, and the like. However, the technologies disclosed in these publications are aimed at improving the processability of rubber compositions and the performance of tire applications such as wear resistance, and the ozone resistance of these compositions is higher than that of conventional conjugated diene polymers. Although some improvement can be seen compared to the composition of , it is inferior to EPDM and its heat resistance is not sufficient.

Furthermore, JP-A No. 1-185341, JP-A No. 2-70
No. 733 and JP-A-2-70734 disclose hydrogenated conjugated diene polymer rubber compositions with good weather resistance. By simply doing so, it is not possible to obtain a rubber composition having sufficient strength, weather resistance, ozone resistance, heat resistance, and compression set resistance.

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned conventional technical problems, and improves ozone resistance, heat resistance, compression set resistance, mechanical strength, and heat resistance. The object of the present invention is to provide a rubber composition with good properties.

[Means for Solving the Problems] As a result of intensive studies on the polymer structure and crosslinking method of hydrogenated conjugated diene polymers, the present inventors found that in order to solve the above problems, hydrogenated conjugated diene polymers It is not enough to specify the polymer structure of the polymer, but it is also necessary to specify the crosslinking method, that is, to make the hydrogenation rate of the hydrogenated conjugated diene polymer extremely high and to use a specific crosslinking system. The inventors have discovered that the above-mentioned problems can be solved by doing the following, and have arrived at the present invention.

That is, the present invention provides an olefinic property of a polybutadiene or styrene-butadiene copolymer having a styrene content of 0 to 40% by weight, a butadiene content of 100 to 60% by weight, and a vinyl bond content of the butadiene moiety of 25 to 70%. 97 unsaturated double bonds
This is a crosslinked rubber composition characterized in that a hydrogenated conjugated diene polymer that is hydrogenated to 100% is crosslinked using a crosslinking agent system consisting of a radical generator and a crosslinking aid.

The rubbery polymer used in the crosslinked rubber composition of the present invention has a specific structure of polybutadiene or styrene-butadiene copolymer with 97 to 100% of the olefinically unsaturated double bonds.
is a hydrogenated conjugated diene polymer.

The hydrogenation rate of this olefinically unsaturated double bond is 97
If it is less than %, the weather resistance and ozone resistance of the crosslinked rubber composition will be poor.

The hydrogenation rate is preferably in the range of 98 to 100%, and 99
A range of 100% is more preferable.

Before hydrogenation, polybutadiene or styrene-butadiene copolymer is polymerized in a hydrocarbon solvent using an alkali metal or alkaline earth metal as a polymerization catalyst, and if necessary, an alkoxide, an organic acid salt, and a vinyl bond amount as a cocatalyst. It is obtained by an anionic polymerization method in which butadiene is polymerized or styrene and butadiene are copolymerized by adding a polar compound such as ether, polyether, or tertiary amine as a regulator, and in particular, by a polymerization method using an organic lithium compound as a polymerization catalyst. It is preferable to obtain

The styrene content of the polybutadiene or styrene-butadiene copolymer before hydrogenation ranges from 0 to 40% by weight, and the butadiene content ranges from 100 to 60% by weight. When the styrene content exceeds 40% by weight,
Rubber elasticity becomes insufficient. Styrene content is 0-30
A range of % by weight is more preferred to provide good heat resistance, and a range of 0 to 20% by weight is particularly preferred.

In the case of styrene-butadiene copolymers, random copolymers, block copolymers, and copolymers combining them are used depending on the purpose, and when the crosslinked rubber composition is made to have particularly good rubber elasticity, , so-called block styrene content (1, M, K.

Ithoff, J., Polymer Sci, 1
, 429 (1946)) is preferably less than 5% by weight of the polymer. On the other hand, if the crosslinked rubber composition is to have high hardness, the amount of block styrene should be 5% by weight or more. Preferably, it is a block copolymer containing. Styrene may exist uniformly in the molecular chain, may increase or decrease along the molecular chain, or may be in the form of bonding random parts with different amounts of styrene.

The amount of vinyl bonds in the butadiene moiety of polybutadiene or styrene-butadiene copolymer before hydrogenation is 2
It ranges from 5 to 70%.

When the amount of vinyl bonds in the butadiene moiety decreases, the rubbery polymer after hydrogenation has a strong tendency to crystallize and exhibit resinous properties. In this case, the tensile strength and hardness of the crosslinked rubber composition at room temperature are high, but the temperature change in the elastic modulus in the service temperature range, that is, 0 to 100° C. is large, which is not preferable. The amount of vinyl bonds, which makes it difficult for a rubbery polymer to crystallize, tends to decrease as the styrene content increases.

- On the other hand, if the amount of vinyl bonds in the butadiene moiety increases, the mechanical strength will decrease and durability will become a problem, and the glass transition temperature will also increase, resulting in poor low-temperature performance.

The amount of vinyl bond in the butadiene moiety is preferably in the range of 30 to 60%, considering the balance of rubber elasticity, low temperature performance, and compression set, and more preferably in the range of 30 to 55%.

The vinyl bonds of the butadiene moiety may exist uniformly within the molecule, may increase or decrease along the molecular chain, or may exist in the form of blocks.

Moreover, the polymer before hydrogenation may have a linear structure, a branched structure, or a mixed structure thereof. A branched structure improves the processability of the polymer after hydrogenation, but an extremely branched structure increases the number of free molecular ends, impairing the heat resistance and mechanical strength of the crosslinked rubber composition. So I don't like it. A polymer having a branched structure is produced by reacting the active end of the polymer with a polyfunctional coupling agent 1 such as silicon tetrachloride, tin tetrachloride, dimethyl adipate, or a polyepoxy compound in the anionic polymerization method described above. It can be obtained by

In addition, the weight average molecular weight (M w
) is preferably in the range of 1 to 1 million, and the molecular weight distribution (M w / M n ) is 1.2 to 5.0.
It is preferable that it is in the range of .

The process for producing the polymer before hydrogenation can be a batch process, a continuous process, or a combination thereof.

The hydrogenated polymer of the present invention can be obtained by subjecting the above conjugated diene polymer to a hydrogenation reaction in a hydrocarbon solvent under a pressure of 1 to 100 kg/ci in the presence of a hydrogenation catalyst to a predetermined hydrogenation rate. It is obtained by

Any method and conditions for the hydrogenation reaction may be used as long as a polymer having a high hydrogenation rate as defined in the present invention can be obtained. Examples of these hydrogenation methods include methods that use catalysts mainly composed of organometallic compounds of titanium, and methods that use catalysts that consist of organic compounds of iron, nickel, and cobalt and organometallic compounds such as alkyl aluminum. how to use,
There are methods that use organic complex catalysts of organometallic compounds such as ruthenium and rhodium, and methods that use catalysts in which metals such as palladium, platinum, ruthenium, cobalt, and nickel are supported on supports such as carbon, silica, and alumina. .

Among various methods.

Using a recently developed homogeneous catalyst consisting of an organometallic compound of titanium alone or an organometallic compound of lithium, magnesium, or aluminum (Japanese Unexamined Patent Publication No. 133203/1983, No. 220147/1983), low pressure, A method of hydrogenation under mild conditions at low temperatures is industrially preferred.

Next, the crosslinked rubber composition of the invention is crosslinked using a crosslinking system consisting of a radical generator and a crosslinking aid.

The polymer with a high hydrogenation rate used in the present invention is a conjugated diene polymer such as natural rubber, BR, or SBR, or a crosslinking system consisting of a combination of sulfur and a vulcanization accelerator used as a crosslinking agent for EPDM. Unable to obtain crosslink density. Furthermore, in the polymer with a high hydrogenation rate used in the present invention, a sufficient crosslink density cannot be obtained even with a crosslinking system using only a radical generator.

As shown in the present invention, by combining a radical generator and a specific type of crosslinking aid in a specific ratio range, the highly hydrogenated polymer used in the present invention can obtain sufficient crosslink density. The crosslinked rubber composition exhibits high tensile strength, low compression set, low heat generation, good heat resistance, good durability, good weather resistance, and ozone resistance.

The radical generator used as a crosslinking agent is a compound that generates radicals when heated, such as a peroxide compound or an azo compound, and preferably an organic radical generator that has good miscibility with the composition of the present invention. Examples of these are dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, 1°1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2
, 5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,
ert-butylperoxy)hexyne-31,2,(1
--bis(tert-butylperoxide isopropyl)benzene, tert-butylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1.1-bis(tert-butylperoxy) ) octane, n-butyl-4,4-bi
s(tert-butylperoxy)valerate, ter
T-butylperoxyisopropyl carbonate, azobisisobutyronitrile, etc. can be used, and it is also possible to use them in combination. The amount of these radical generators is 0.002 mol to 0.1 mol per 100 parts by weight of the polymer.
Use in molar range. The amount of radical generator is 0.00
If it is less than 2 moles, crosslinking will not be sufficient, resulting in poor elasticity and tensile strength, and if it exceeds 0.1 mole, elongation, tensile strength will decrease, and durability will be poor. This amount is 0.00 parts per 100 parts by weight of polymer.
The range of 0.005 mol to 0.05 mol is more preferable.

Next, the compound used as a crosslinking aid is a compound that has the function of increasing the crosslinking efficiency of the radical generator. These compounds include sulfur, N.

N--m-phenylene bismaleimide, p-quinone dioxime, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, etc. can be used, and they can also be used in combination. .

The amount of the crosslinking aid used is within a certain molar ratio to the radical generator, and the amount is between 0.2 mol and 5 mol per mol of the radical generator. 06
The range of 5 mol to 2 mol is preferred.

If the amount of the crosslinking aid is less than 0.2 mol per mol of the radical generator, sufficient crosslinking will not be achieved, and if it exceeds 5 mol, the crosslinking density will decrease and the compression set will be poor. The amount of crosslinking aid is 0.5 mol to 1 mol of radical generator.
A range of 2 moles is more preferred.

The crosslinked rubber composition of the present invention may optionally contain ethylene-propylene polyene copolymer rubber (E
PDM), ethylene-propylene rubber (EPM), butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene, epichlorohydrin rubber, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butane rubber, styrene-butadiene rubber, polybutadiene rubber, poly Isoprene rubber, natural rubber, etc. can be added.

The crosslinked rubber composition of the present invention can be blended with various compounding agents that are normally blended into rubber compositions.

These compounding agents include reinforcing agents, fillers, softeners, plasticizers,
Processing aids, antioxidants, anti-aging agents, anti-scorch agents,
These include ultraviolet inhibitors, lubricants, foaming agents, foaming aids, flame retardants, antistatic agents, and anti-coloring agents.

Examples of reinforcing agents to be added to the crosslinked rubber composition of the present invention include carbon black SAF, 15AF, HAF, FEF,
Furnace black of SRF, thermal black such as MT, FT, inorganic reinforcing agents such as white carbon, basic calcium carbonate, activated calcium carbonate, organic reinforcing agents such as high styrene resin, coumaron-indene resin, phenol formaldehyde resin, etc. carbon black and inorganic reinforcing agents are preferred. If a reinforcing agent is used, the amount used is 5 to 200 parts by weight per 100 parts by weight of the polymer.

As fillers, calcium carbonate, clay, talc, zeolite, diatomaceous earth, aluminum sulfate, barium sulfate, etc. can be used.

As the softener, paraffinic process oil, naphthenic process oil, aromatic process oil, paraffin wax, petroleum resin, asphalt, vegetable oil-based softener, sub-types, etc. are used. Particularly preferred are paraffinic process oils, naphthenic process oils, and aromatic process oils. When a softener is used, the amount used is 1 to 20 parts by weight per 100 parts by weight of the polymer.
It is 0 parts by weight.

The amounts of the reinforcing agent and softening agent mentioned above are selected in consideration of the hardness and elastic modulus of the resulting crosslinked rubber composition.

As plasticizers, phthalic acid derivatives, adipic acid derivatives,
Trimellitic acid derivatives, oleic acid derivatives, stearic acid derivatives, phosphoric acid derivatives, etc. can be used.

As processing aids, fatty acids such as stearic acid, lauric acid, and palmitic acid, and metal salts thereof can be used.

As antioxidants or anti-aging agents, amine derivatives such as diphenylamine type and p-phenylenediamine type;
Quinoline derivatives, hydroquinone derivatives, monophenols, diphenols, thiobisphenols, hindered phenols, phosphorous esters, etc. can be used.

Known rubber compounding chemicals such as ultraviolet inhibitors, lubricants, foaming agents, foaming aids, flame retardants, antistatic agents, anti-coloring agents, and others are used depending on the purpose of use.

The crosslinked rubber composition of the present invention can be prepared by compounding,
A crosslinked rubber composition is obtained through the steps of kneading, molding, and crosslinking.

The crosslinked rubber composition of the present invention can be used as known rubber products, such as anti-vibration rubber for tire tubes, engine mounts, bushings, stoppers, etc.
It can be used for various purposes such as window frames, glass runs, sponges, tarpaulins, roofings, electric wires, packing, heater hoses, radiator hoses, and other industrial products, automobile parts, and construction materials.

EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples, but these are not intended to limit the scope of the present invention.

[Examples] Hydrogenated polybutadiene (samples 1 to 5) within the range of polymer structures defined in the present invention shown in Table 1, hydrogenated styrene-butadiene copolymers (samples 6 to 12), and books shown in Table 2 Hydrogenated polybutadiene for comparison (Sample 13.14.17) and hydrogenated styrene butadiene copolymer for comparison (Sample 15), which are outside the scope of the invention.
．． Furthermore, an ethylene-propylene copolymer (sample 2o) and an ethylene-propylene-polyene copolymer (sample 21°22) shown in Table 3 were prepared for comparison.

The hydrogenated polybutadiene and hydrogenated styrene-butadiene copolymer in Tables 1 and 2 are obtained by polymerizing butadiene or copolymerizing styrene and butadiene in a cyclohexane solvent containing a small amount of tetrahydrofuran using an organolithium catalyst. This sample was obtained by subsequent hydrogenation using di-p-tolylbis(1-cyclopentadienyl)titanium and n-butyllithium as hydrogenation catalysts.

The styrene content of the polymer, the amount of vinyl bonds in the butadiene moiety, and the weight average molecular weight (Mw).

The molecular weight distribution (M w / M n ) and hydrogenation rate were measured by the methods shown below.

Styrene content, UV 254n due to phenyl group of styrene when the polymer before hydrogenation is dissolved in chloroform
It was measured by the absorption of m.

Amount of vinyl bonds in the butadiene moiety: The polymer before hydrogenation was dissolved in deuterated chloroform, and FT-NMR (270 M,
(manufactured by JEOL Ltd.), the NMR spectrum was measured, and a proton (diCH2) due to a 1,2 bond with a chemical shift of 4.7 ppm to 5.2 ppm, and a proton (diCH2) with a chemical shift of 5.2 ppm to 5.
．． Calculated from the integrated intensity ratio of protons (=CH) of 8 ppm.

Weight average molecular weight (M w ) and molecular weight distribution (M
w/M n ) The polymer before hydrogenation was dissolved in THF (
Tetrahydrofuran) solution and GPC (LC-5A manufactured by Takasu Seisakusho Column: Polystyrene gel HSG-
40, 50, 60 each, detector: differential refractometer),
Measure the chromatogram. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) in terms of polystyrene were calculated and determined by a conventional method using a calibration curve showing the relationship between the peak molecular weight and retention flow rate of standard polystyrene.

Hydrogenation rate: The polymer before hydrogenation and the polymer after hydrogenation were dissolved in deuterated chloroform, and subjected to FT-NMR (270
The NMR spectra of each were measured using Mega, manufactured by JEOL Ltd., and the chemical shift of the polymer before hydrogenation was 4.7.
ppm to 5.2 ppm of protons (=
CH2) and the integrated intensity of the proton (=CH-) with a chemical shift of 5.2 ppm to 5.8 ppm, while for the polymer after hydrogenation, the chemical shift o, 61) pI
Calculate the integrated intensities of methyl protons (-CH3) due to hydrogenated 1 and 2 bonds of ~L Oppm, 1° (=CH2) without chemical addition of sulfurine, and protons without chemical addition of sulfurine, and The hydrogenation rate of 5.2 ppm to 5.3 ppm of water (=CH-) due to 4.7 ppm to 5.2 ppm of water 2 bonds was calculated.

(Removal) Table Example 1 and Comparative Example 1 Using Sample 1 having a polymer structure within the range limited by the present invention, a B-type Banbury mixer was prepared using the evaluation formulation shown in Table 4.
The mixture was kneaded to obtain a rubber composition, which was then crosslinked using various crosslinking systems shown in Table 5. The crosslinking temperature was 160°C, a crosslinking curve at 160°C was obtained for each crosslinking system using a Monsande rheometer, the optimum vulcanization time was determined by a conventional method, and crosslinking was carried out for a predetermined period of time.

Table 5 shows the performance measurement results of these samples.

Further, for comparison, EPDM was used and the performance was similarly measured as a crosslinked composition using the crosslinked system shown in Table 6, and the results are shown in Table 6.

Each measurement was performed as follows.

(1) Hardness, tensile test Measured according to JIS-6301.

(2) Gutdrich heat generation: Using a Gutdrich heat generation tester, according to ASTM-D623-58, stroke 0
．． Measured under the conditions of 225 inches, load 55 bond, and test temperature 50°C, and measured the temperature rise (8T) of the test piece after 20 minutes.

(3) Durability ASTM-D430-59 Met
According to the method using the De Mattia bending tester of h o d -B, a JIS-3 dumbbell test piece was repeatedly stretched 100% at 23°C with a gauge line spacing of 20 mm, and the number of times until the sample broke was calculated. measurement.

(4) Heat aging resistance: according to JIS-6301,
Air aging was performed in a gear aging tester set at 125°C, and changes in hardness, tensile strength, and elongation were measured.

(5) Compression set: 125 according to JIS-6301
Measure the strain after 70 hours at °C.

(6) Ozone resistance According to JIS-6301,
Under the conditions of 40°Cl2O% elongation and ozone concentration lppm,
Observe the occurrence of cracks after 500 hours of ozone exposure. JIS
Displays the number, size and depth of cracks according to the number of cracks.

From the results in Table 5, the crosslinked rubber compositions in which the peroxide compounds of Examples 1-1 to 1-5 and sulfur are crosslinked, the peroxide compounds of Examples 1-6 to 1-9, and N,N-m −
Crosslinked rubber compositions consisting of crosslinked systems with phenylene bismaleimide, triallyl isocyanurate, and other specific compounds have sufficient modulus, high tensile strength, low gludrich heat generation, good durability, good heat aging resistance, and low compression. Shows permanent set and good ozone resistance.

On the other hand, even if Sample 1 is used, the composition of Comparative Example 1-1 in which the crosslinking system is a peroxide compound alone, and the composition of Comparative Example 1-2 in which the crosslinking system is a combination system with a substance that does not have a function as a co-crosslinking agent. The composition of Comparative Example 1-3, which is based on a crosslinking system in combination with a general vulcanization accelerator and sulfur, does not have sufficient crosslinking density, has low tensile strength, high heat generation, and has poor ozone resistance. Sex is also inferior.

Furthermore, the crosslinked rubber compositions using EPDM for comparison shown in Table 6 were inferior to the crosslinked rubber compositions of the present invention in terms of heat generation and durability, even in Comparative Examples 1-4, which had the same crosslinking system as the present invention. Comparative Example 1-5, which uses a peroxide compound alone, has inferior tensile strength and durability, and Comparative Example 1-6, which uses a general crosslinked system of sulfur and a vulcanization accelerator, has poor durability, heat aging resistance, and compression durability. The strain was poor, and none of them had better performance than the crosslinked rubber compositions of the present invention in Examples.

(Removed residual color) Table evaluation formulation (Example 1゜Comparative Example 1) Polymer N330 Carbon Black Paraffin Process Oil *1 Zinc white stearic acid Part by weight Part by weight Part by weight Crosslinking system variable *1: Hiko Kosan Example 2 and Comparative Example 2 Hydrogenated polymers with polymer structures shown in Table 1 that fall within the scope of the limitations of the present invention, Hydrogenated polymers of the present invention shown in Table 2 Hydrogenated polymers for comparison of polymer structures not in the limited range, ethylene propylene copolymers and ethylene-propylene polyene copolymers shown in Table 3 were used, and the same crosslinked system was used with the formulation shown in Table 7. A crosslinked rubber composition was obtained in the same manner as in Example 1, and its performance was measured. The results are shown in Tables 8 and 9.

From the results in Tables 8 and 9, each of the crosslinked rubber compositions of Examples using Samples 1 to 12 having a styrene content, a vinyl bond amount in the butadiene moiety, and a hydrogenation rate within the ranges defined in the present invention, It is clear that there is little change in hardness with temperature, sufficient modulus, high tensile strength, low heat generation, good durability, good heat aging resistance, low compression set, and good ozone resistance.

In contrast, the crosslinked rubber compositions of each comparative example using samples 13 to 19 of hydrogenated polymers for comparison whose polymer structure does not fall within the scope of the limitations of the present invention, and the ethylene-propylene copolymer A crosslinked rubber composition using an ethylene-propylene-polyene copolymer has one or more of the following properties: temperature change in hardness, tensile strength, heat generation, durability, heat aging resistance, compression set, and ozone resistance. performance is poor.

(Futoshita Nairaku) Ratings: 5 (Example 2゜Comparative Example 2) Polymer N330 Carbon Black Paraffinic Process Oil 8 Zinc White Stearic Acid Parts by Weight Parts by Weight Parts by Weight Dicumyl Peroxide Sulfur 2.70 Part by weight: 0.32 parts by weight*1 Diana Process Oil PW380 manufactured by Idemitsu Kosan [Effects of the Invention] As described above, the crosslinked rubber composition according to the present invention has good tensile strength, low heat build-up, good durability, and good properties. It has excellent characteristics as a crosslinked rubber composition, such as high heat resistance and good ozone resistance, and is extremely suitable for use in rubber products such as various industrial products and automobile parts, and has industrial significance. is big.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. Olefinically unsaturated double polybutadiene or styrene-butadiene copolymer with a styrene content of 0 to 40% by weight, a butadiene content of 100 to 60% by weight, and a vinyl bond content of the butadiene moiety of 25 to 70%. A crosslinked rubber composition characterized in that a hydrogenated conjugated diene polymer in which 97 to 100% of the bonds are hydrogenated is crosslinked with a crosslinking agent system comprising a radical generating compound and a crosslinking aid.