JPH06263923A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition containing a hydrogenated unsaturated nitrile-conjugated diene-based copolymer, a vinyl chloride resin and a silicone rubber, capable of producing a vulcanized product excellent in resin tances to weather, abrasion, heat, oil and ozone, etc. CONSTITUTION:This rubber composition contains (A) a hydrogenated unsaturated nitrile-conjugated diene-based copolymer (e.g. a hydrogenated material of a butadiene-acrylonitrile copolymer rubber) having <=120 iodine value, (B) a vinyl chloride resin (preferably a powdery material having 800 to 1500 polymerization degree and a small average particle size) and (C) a silicone rubber (preferably a rubbery material having >=400000 molecular weight) preferably in a weight ratio of 100 pts.wt. component (A), 5 TO 30 pts.wt. component (B) and 1 to 20 pts.wt. component (C). This composition is prepared preferably by kneading the component (A) with the component (B) and subsequently blending the component (C) therewith. In addition, an organic peroxide such as dicumyl peroxide is preferably used as the vulcanizing agent for the composition.

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, and more particularly to a hydrogenated unsaturated nitrile-conjugated diene copolymer excellent in oil resistance, weather resistance, low friction property and abrasion resistance. It relates to a vulcanizable rubber composition as a component.

[0002]

2. Description of the Related Art Hydrogenated unsaturated nitrile-conjugated diene copolymers obtained by hydrogenating a part of carbon-carbon double bond-containing monomer units in unsaturated nitrile-conjugated diene copolymers have hitherto been heat-resistant. It is well known that it has excellent properties. The present inventor previously produced a composition in which a silicone polymer was added as a friction modifier to reduce the friction of these rubber compositions, but the dispersibility of the silicone polymer in the composition was poor, There is a drawback that the friction reducing effect is not sufficiently exhibited.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the dispersibility in a friction reducing agent while maintaining the heat resistance and oil resistance of the above-mentioned conventional nitrile rubber composition, and further has ozone resistance and sour gasohol resistance. It is an object of the present invention to provide a sliding product which has a low friction coefficient and a small amount of wear due to a rubber composition having good properties, and therefore has durability both chemically and physically.

[0004]

Means for Solving the Problems As a result of intensive research to solve the above problems, the present inventors have found that a rubber composition obtained by blending a vinyl chloride resin with a hydrogenated unsaturated nitrile-conjugated diene copolymer is It has been found that the composition has excellent ozone resistance, sour gasoline resistance, and sour gasohol resistance, and increases the dispersibility of the silicone rubber that is a friction reducing agent. It was found that the product produced from the rubber composition obtained by mixing the above rubber composition with silicone rubber has excellent wear resistance and slidability because the composition of the material has good low friction properties. Based on this, the present invention has been completed.

That is, according to the present invention, (1) the iodine value is 1
A rubber composition comprising 20 or less hydrogenated unsaturated nitrile-conjugated diene copolymer, (2) vinyl chloride resin and (3) silicone rubber as constituent components. The hydrogenated unsaturated nitrile-conjugated diene-based copolymer used as a constituent component of the composition of the present invention includes unsaturated nitrile-conjugated diene copolymer and unsaturated nitrile-conjugated diene-ethylenically unsaturated monomer copolymer. A hydrogenated double bond portion remaining in the conjugated diene unit can be used, and a hydrogenated nitrile group contained in the copolymer is not used. They are,
A copolymer produced by emulsion polymerization or solution polymerization,
Normal method (for example, Japanese Patent Publication No. 60-58242)
Method described in Japanese Patent Publication No. 62-61045)
Is a hydrogenated part of the conjugated diene unit in the copolymer, and its iodine value is 120 because of the requirement of heat resistance.
The following is used, and preferably 50 or less is used. Further, in the case of vulcanization with sulfur, vulcanization time becomes long if it is completely hydrogenated, so it is desirable to leave about 2% of non-hydrogenated double bonds (about 5 in iodine value ratio). . Acrylonitrile, methacrylonitrile, etc. are used as the unsaturated nitrile constituting the hydrogenated unsaturated nitrile-conjugated diene-based copolymer used in the composition of the present invention, and 1,3-butadiene, 2,3-dimethyl is used as the conjugated diene. Examples thereof include butadiene, isoprene, and 1,3-pentadiene.

The ethylenically unsaturated monomers copolymerizable with these unsaturated nitrile monomers include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid; methyl acrylate, butyl acrylate, maleic acid. Alkyl esters of said carboxylic acids such as dimethyl acid ester, diethyl fumarate, di-n-butyl fumarate, di-n-butyl itaconic acid; unsaturated carboxylic acids such as methoxy acrylate, ethoxyethyl acrylate, methoxyethoxyethyl acrylate Alkoxyalkyl esters of acids; acrylates having cyanoacryl groups such as α and β-cyanoethyl acrylate, α, β and γ-cyanopropyl acrylate, cyanobutyl acrylate, cyanooctyl acrylate; 2-
Acrylate having hydroxyalkyl group such as hydroxyethyl acrylate and hydroxypropyl acrylate; acrylamide, methacrylamide; N-methylol (meth) acrylamide, N, N'-dimethylol (meth) acrylamide, N-ethoxymethyl (meth)
N-substituted (meth) acrylamides such as acrylamide are included. In addition to these monomers, a part of the unsaturated monomer may be a vinyl-based monomer such as styrene or vinylpyridine, vinyl norbornene, dicyclopentadiene, 1 or 2 within a range not impairing the gist of the present invention. It may be replaced by a non-conjugated diene such as 1,4-hexadiene. The hydrogenated unsaturated nitrile-conjugated diene copolymer used in the composition of the present invention is specifically a butadiene-acrylonitrile copolymer rubber (hereinafter abbreviated as NBR), isoprene-butadiene-acrylonitrile copolymer rubber, isoprene- Hydrogenated acrylonitrile copolymer rubber; butadiene-methyl acrylate-acrylonitrile copolymer rubber, butadiene-acrylic acid-acrylonitrile copolymer rubber, butadiene-itaconic acid di-n-butyl-acrylonitrile copolymer rubber, etc. The thing etc. are illustrated. The amount of the bound unsaturated nitrile in the copolymer rubber is usually 5 to 60% by weight, preferably 10 to 5 due to the requirement of oil resistance.
It is 0% by weight. Further, as long as the effect of the present invention is not impaired, a part of the hydrogenated unsaturated nitrile-conjugated diene-based copolymer may be replaced with a non-hydrogenated unsaturated nitrile-conjugated diene-based copolymer. .

The vinyl chloride resin used as a constituent of the present invention is a polyvinyl chloride homopolymer and a known vinyl chloride unit content of 60% by weight of a vinyl chloride unit and another monomer capable of radically copolymerizing with vinyl chloride. % Or more copolymers can be used without particular limitation, for example, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate polymer graft copolymer of vinyl chloride, a small amount of divinylbenzene, diallyl phthalate. It is possible to use a partially crosslinked vinyl chloride resin obtained by copolymerizing a bifunctional monomer such as Vinyl chloride resin used in the composition of the present invention,
Polymerization degree 200-3000, preferably 800-150
No. 0 can be used, and a powdery one having a small average particle size can be suitably used because it is convenient for kneading. The blending ratio of the vinyl chloride resin used in the present invention is
It is desirable to use 1 to 50 parts by weight, particularly 5 to 30 parts by weight, based on 100 parts by weight of the hydrogenated unsaturated nitrile-conjugated diene copolymer. Addition amount of vinyl chloride resin is 1
If it is less than 50 parts by weight, the dispersibility in a friction reducing agent such as silicone rubber will be insufficient, and if it exceeds 50 parts by weight, the desired properties as a rubber product will change depending on the case. The silicone rubber used as the friction reducing constituent of the composition of the present invention is preferably a rubber-like one having a molecular weight of 200,000 or more, particularly 400,000 or more. Also, various types such as dimethyl type, methyl vinyl type, methyl phenyl vinyl type are known.
These known silicone rubbers can be used without particular limitation. A low molecular weight liquid silicone is not preferable because it lowers the strength of the rubber composition.

The silicone rubber used in the composition of the present invention is added in an amount of hydrogenated unsaturated nitrile conjugated diene copolymer 1
1 to 30 parts by weight per 00 parts by weight, preferably 1 to 20 parts
The range is parts by weight. Even if the amount of silicone rubber added exceeds 30 parts by weight, there is no friction reduction effect commensurate with the addition and it is necessary to increase the amount of vinyl chloride resin to maintain dispersibility. Width is limited,
In addition, roll processability also becomes poor. The vulcanizing agent of the composition of the present invention is not particularly limited, and a sulfur-based vulcanizing agent or an organic peroxide-based vulcanizing agent is used, and the latter is preferable among them. Examples thereof include dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl- 2,5-di (benzoylperoxy) hexyne and the like can be mentioned. These organic peroxides can be used in one kind or more, and can be used usually in the range of 0.2 to 10 parts by weight with respect to 100 parts by weight of rubber. In the composition of the present invention, together with the above components, zinc white, stearic acid, carbon black, reinforcing agents such as silica, talc, fillers such as calcium carbonate,
Various publicly known rubber additives commonly used in the rubber industry such as triallyl isocyanurate, crosslinking aids such as trimethylolpropane, plasticizers, process oils, processing aids, and antioxidants are appropriately selected according to the purpose of use. Then, they can be mixed and kneaded. The composition of the present invention can be produced by mixing the above-mentioned components with a mixer such as a kneading roll machine or a closed mixer, which is usually used for kneading rubber. The order of mixing the respective components in this case is not particularly limited, but to the hydrogenated unsaturated nitrile conjugated diene-based copolymer, after kneading a vinyl chloride resin component having good compatibility with the copolymer, It is desirable to mix the silicone rubber from the viewpoint of uniform composition and greatly shortening the kneading time.

[0009]

EXAMPLES Hereinafter, the composition of the present invention will be specifically described with reference to Examples. In the examples, the normal physical properties are JIS K-
It measured according to 6301. The friction coefficient and the amount of friction were measured as follows. (1) Friction coefficient Using a vulcanized sheet having a thickness of 2 mm, the friction coefficient was measured with a Haydon friction coefficient measurement tester. An alumina indenter having a diameter of 10 mm was placed on the sheet, and a load of 100 g was applied on the sheet, followed by pressure bonding for 1 minute, followed by measurement. The temperature is 23
It was carried out under the conditions of ℃ and speed of 30 mm / min. (2) Abrasion amount A vulcanized sheet having a thickness of 2 mm was used to measure the abrasion amount with a Taber abrasion tester. For the measurement, a wear wheel of H-18 was used, and first, preliminary cutting was performed 1000 times with a load of 1 kg. Next, in this test, the amount of wear when shaving 1000 times under conditions of a temperature of 23 ° C. and a load of 1 kg was expressed in cc.

Examples 1 to 3 and Comparative Examples 1 to 2 Hydrogenated acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 36% by weight and an iodine value of 28 (hydrogenation rate of 90%) was used, and each component shown in Table 1 was used. According to the compounding recipe, a vinyl chloride resin and a silicone rubber were added in this order to the hydrogenated acrylonitrile-butadiene copolymer and kneaded with a roll to produce a composition, and a rubber compound was prepared. This was heated under pressure at 170 ° C. for 20 minutes to obtain a sheet-shaped vulcanization test piece having a thickness of 2 mm, and each physical property was measured. The results are shown in Table 1.

[0011]

[Table 1]

Note 1) Zetpol2020 [manufactured by Nippon Zeon Co., Ltd. (AN amount 36%, iodine value 28)] 2) Daiichi 101 [manufactured by Nippon Zeon Co., Ltd. (average degree of polymerization 1
450, average particle size 120 μ)] 3) Lord Sil Silicone MM7616 [Rhone Poulean Silicone] 4) Valcup 40KE [Hercules, α, α'-
Bis (t-butylperoxy) -p-diisopropylbenzene] 5) Amine anti-aging agent Naugard 445 [manufactured by Shiraishi Calcium Co.] Further, as a result of testing the ozone resistance and gasohol resistance of these rubber compositions, The composition of the example to which vinyl chloride was added showed better ozone resistance and gasohol resistance than the composition of Comparative Example 1.

[0013]

The composition of the present invention retains the heat resistance and oil resistance which are the characteristics of the hydrogenated unsaturated nitrile-conjugated diene copolymer, and improves the dispersibility of the silicone rubber.
The vulcanized product has excellent weather resistance, low friction property, and wear resistance, and can be applied to a wide range of applications. For example, it is suitable as a material for hoses, seals, rolls and the like, as well as sliding parts such as glass runs and wipers for automobiles as main applications.

Claims (2)

[Claims] 1. A hydrogenated unsaturated nitrile-conjugated diene copolymer having an iodine value of 120 or less, (2) vinyl chloride resin and (3) silicone rubber as constituent components. Rubber composition. 2. A method in which (1) a hydrogenated unsaturated nitrile-conjugated diene-based copolymer having an iodine value of 120 or less is mixed with (2) a vinyl chloride resin, and (3) a silicone rubber is added. The rubber composition according to claim 1, which is characterized in that.