JPS63202641A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition having excellent tensile strength, heat resistance and oil resistance after vulcanization, crosslinkable in steam, air, etc., by blending ethylene.propylene.nonconjugated polyene copolymer rubber having a specific composition with a naphthenic oil and an inorganic filler. CONSTITUTION:(A) 100pts.wt. ethylenic copolymer rubber having a molar ratio of ethylene/propylene of 86/14-97/3, 6-17mol.% sum of propylene and nonconjugated polyene and A shown by the formula [P is propylene content; D is nonconjugated polyene content; E is ethylene content (all in mol.%)] of >=0.1 is blended with (B) 10-150pts.wt. naphthenic or paraffinic oil and (C) 40-150pts.wt. inorganic filler (white filler such as talc, clay, etc., or carbon black). 5-Ethylidene-2-norpornene and dicyclopentadiene are preferable as the polyene compound in the component A and the amount of the compound contained in the copolymer is 3-6mol.%.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to ethylene/propylene/polyene copolymer rubber, and furthermore to ethylene/propylene/polyene copolymer rubber having excellent tensile strength, oil resistance, and heat resistance after vulcanization. The present invention relates to a vulcanized rubber composition comprising a polymeric rubber, a filler and a plasticizer.

Ethylene-propylene copolymer rubber has heat resistance, cold resistance,
It has excellent weather resistance and is used in automobile parts, industrial products, electrical parts, etc., such as socket covers, heat-resistant hoses, electric wires, condenser caps, heat-resistant belts, and various vibration-proof rubber packings.

<Conventional technology> Ethylene-propylene copolymer rubber has excellent weather resistance, heat resistance, and ozone resistance, and is used as building materials, electric wire materials,
It is known to be used for automobile parts.

It is known that ethylene-propylene copolymer rubber with a high ethylene content is preferable for such uses that particularly require high strength.

Furthermore, it is known that ethylene/propylene copolymer rubber that does not contain polyene is preferable for applications requiring heat resistance.

However, if a polymerization recipe with a high ethylene content is used to satisfy the former requirement, problems arise, such as gelation occurring in the polymerization tank. Furthermore, ethylene/propylene copolymer rubber that does not contain polyene to satisfy the latter requirement has problems such as not being able to obtain a sufficient crosslinked product in steam or air when crosslinked with organic peroxides. ing.

Furthermore, since such ethylene/propylene copolymer rubber does not have a scratchable group in its main chain, satisfactory results regarding oil resistance have not always been obtained. There was no known means for obtaining an ethylene-propylene copolymer composition that solved all of these problems.

<Problems to be solved by the invention> The purpose of the present invention is to solve such problems and improve tensile strength,
The object of the present invention is to provide a rubber composition made of an ethylene-propylene-polyene copolymer that has excellent heat resistance and oil resistance and can be crosslinked in steam or air.

Means for Solving the Problems> The present inventors have achieved this objective as a result of intensive study on ethylene-propylene-polyene copolymer rubber that has excellent tensile strength, heat resistance, and oil resistance after vulcanization. We have discovered an ethylene-propylene-polyene copolymer rubber composition.

That is, the present invention consists of (1) (A) ethylene, propylene, and non-conjugated polyene, and (a) the ethylene/propylene ratio (molar ratio) is 86/14.
(b) an ethylene copolymer rubber 10 in which the total of propylene and nonconjugated polyene is 6 to 17 mol%, and in the formula, A≧0.1
0 parts by weight, [where P indicates the propylene content in the copolymer rubber, D indicates the non-conjugated polyene content, and E indicates the ethylene content (both are mole %). ] (B) naphthenic or paraffinic oil 10 to 1
50 parts by weight, and 40 to 150 parts by weight of an inorganic filler or carbon black.A rubber composition with excellent tensile strength, heat resistance, and oil resistance. It is about things.

Specifically, the non-conjugated polyene used in the present invention is 1
-4-hexadiene, dicyclopentadiene, methyldicyclopentadiene, vinylnorbornene, 5-ethylidene-2-norbornene, isopropenylnorbornene, etc., but especially dicyclopentadiene, 5-ethylidene-2-norbornene. preferable. The content of the polyene compound is selected to be 6 mol% or less, preferably in the range of 3 to 6 mol%. If the content of the polyene compound is 6 mol % or more, the cost will increase and no increase in effectiveness can be expected.

In the present invention, the inorganic filler (B) includes white fillers such as silica, talc 1, and clay, and such white fillers may be used in combination with carbon black.

As the oil (B), paraffinic or naphthenic oils are preferred.

In the present invention, the blending amounts of carbon black, inorganic filler, and oil are arbitrarily selected from the above-mentioned ranges depending on the desired physical properties.

In the production of the copolymer of the present invention, a so-called Ziegler-Natsuta catalyst is used, and a catalyst system consisting of an organoaluminum compound, a trivalent to pentavalent vanadium compound soluble in a hydrocarbon solvent, and an ester of a halogenated organic acid is used. be done. The aluminum compound is preferably alkyl aluminum sesquichloride, trialkyl aluminum, dialkyl aluminum monochloride, or a mixture thereof, and the vanadium compound is oximivanadium chloride, vanadium tetrachloride, or VO(OR).
, , X, -n (0<n≦3, R is a linear, branched, or cyclic hydrocarbon having 1 to 10 carbon atoms) and the like are exemplified.

Furthermore, examples of esters of halogenated organic acids include methyl trichloroacetate, ethyl trichloroacetate, propyl trichloroacetate, methyl perchlorocrotonate, ethyl perchlorocrotonate, butyl perchlorocrotonate, and the like.

The ratio of organoaluminum compound to vanadium compound and ester of halogenated organic acid may vary within a wide range, but the ratio of organoaluminum compound to ester of halogenated organic acid may range from 100:1 to 2:1 (mol% ), the ratio of ester of halogenated organic acid to vanadium compound is preferably in the range of o,i: 1 to 100:1. Further, the ratio of the organoaluminum compound to [(ester of halogenated organic acid)+(vanadium compound)] is preferably in the range of 1001 to 2.1:1 (molar ratio).

The copolymer rubber used in the present invention is produced using the above catalyst system, but the polymerization reaction can be carried out using commonly used hydrocarbon or halogenated hydrocarbon solvents, such as hexane, heptane, kerosene, cyclohexane, and benzene. It is carried out by solution polymerization using chloroform, trichloroethylene, tetrachloroethane, etc.

The polymerization temperature can vary within a wide range, but is usually between -50 and -10
It is carried out at 0°C, preferably -30 to 80°C, and more preferably 30°C.
C to 80C is particularly preferred.

Polymerization is carried out at atmospheric pressure or under pressure, from 1 to 50 K.
Preferably it is carried out under a pressure of g/-.

Furthermore, in these production methods, commonly used molecular weight regulators can be used to arbitrarily control the molecular weight of the produced polymer. That is, diethylzinc, allyl chloride, pyridine-
N-oxide, hydrogen, etc. are often used, and hydrogen is particularly preferred.

The vulcanizing agent used in the present invention is sulfur or an organic peroxide. As organic peroxide vulcanizing agents, peroxyketals such as 1,1-bis(t-butylperoquine)3,3,5-trimethylcyclohexane, di-t-
Examples include dialkyl peroxides such as butyl peroxide and dicumyl peroxide.

Examples of the vulcanization aid used in the present invention include diphenylguanidine, mercaptobenzothiazole, N-cyclohexylbenzothiazyl sulfenamide, mercaptobenzothiazole zinc salt, and sodium dimethyl dithiocarbamate. Those known in the industry are used.

Antiaging agents used in the present invention include 2-mercaptobenzimidazole, trinonylphenyl phosphite, 2-6 di-t-butyl-4 methyl-phenol, 1
, l-bis-(4-hydroxy-phenyl)-cyclohexane, N-phenyl-N'-isopropyl-P-phenyl diamine, which are commonly known as anti-aging agents or antioxidants in the rubber industry are used. be done.

The method for blending (B) carbon black, inorganic filler, and naphthenic or paraffinic oil with the thus obtained (A) copolymer rubber is carried out by a conventional kneading method using a Banbury mixer, rolls, etc. be able to. Further, as the vulcanization method, both sulfur vulcanization and peroxide vulcanization are possible, and a vulcanized product can be obtained by employing an ordinary press vulcanization method or continuous vulcanization method.

By using the rubber composition according to the present invention, a vulcanizate having excellent tensile strength, heat resistance, and oil resistance can be obtained.

This vulcanizate is used for socket covers, heat-resistant hoses, electric wires, condenser caps, heat-resistant belts, anti-vibration rubber, various packings, automobile parts, etc.

<Examples> The present invention will be explained using examples, but these are not intended to limit the invention in any way.

Examples 1 to 4 and Comparative Examples 1 to 4 Table 1 shows the characteristic values of the copolymer rubbers used, and Tables 2 and 3 show the formulation and vulcanized physical properties.

The kneading was carried out as follows.

Filler, oil and polymer were added at the same time using Kobe Steel's new BR type Banbury (inner volume 1.5G).
The mixture was kneaded for 5 minutes at p. The temperature at the start was 70°C, and the temperature rose to 150°C at the end of kneading. The vulcanizing agent and vulcanizing aid were added using a 10-inch open roll at 50°C. Vulcanization was carried out using a steam press, and the composition in Table 2 was 16
The test was conducted at 0°C for 15 minutes, and in the case of the formulation shown in Table 3, at 160°C for 20 minutes.

Vulcanized physical properties were measured according to JIS K-6301. Compression set was performed under the conditions of 125°C x 22 hours, oil resistance was measured using JIS No. 3 oil, volumetric swelling rate after 70 hours at 150°C, and heat resistance was measured by tensile properties after heat aging at 120°C for 5 days. did.

<Effects of the Invention> As explained above, according to the present invention, compared to the prior art,
Ethylene α- with excellent vulcanizate physical properties, oil resistance, and heat resistance
An olefin copolymer rubber composition can be provided.

Claims (2)

[Claims] (1) (A) Consists of ethylene, propylene and non-conjugated polyene, (a) ethylene/propylene ratio (molar ratio) is 86/14
(b) the sum of propylene and nonconjugated polyene is 6 to 17 mol%, and the formula A=(42P+120D)/(42P+120D+28
In E), for 100 parts by weight of ethylene copolymer rubber where A≧0.1, [where P is the propylene content in the copolymer rubber, D is the non-conjugated polyene content, and E is the ethylene content (both are (mol%). ] (B) 10 to 150 parts by weight of naphthenic or paraffinic oil and 40 to 1 part of inorganic filler or carbon black
50 parts by weight of a rubber composition. (2) The rubber composition according to claim 1, wherein the polyene compound (A) is 5-ethylidene-2-norbornene or dicyclopentadiene, and the content thereof is 3 to 6 mol%.