JPH06263924A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber, composition composed of specified three components, excellent in resistances to heat, oil, ozone, etc., and extrusion workability, and also excellent in dispersion of an abrasion-reducing agent such as a silicone rubber and, therefore, capable of producing a product low in abrasion and excellent in slidability. CONSTITUTION:This rubber composition is prepared by blending (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) an ethylenic unsaturated carboxylic acid metal salt (preferably zinc methacrylate, etc.) and (C) a vinyl chloride resin (preferably a powdery material having 800 to 1500 polymerization degree and a small average particle size). The amount of the component (B) is 5 to 100 pts.wt. based on 100 pts.wt. rubber and the amount of the component (C) is 5 to 30 pts.wt. based on 100 pts.wt. component (A). In addition, an organic peroxide such as dicumly 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 specifically, it has excellent strength properties, oil resistance, weather resistance and extrusion processability, and is a dispersion of an organic additive added as a friction reducing agent. A vulcanizable rubber composition having a good hydrogenation unsaturated nitrile-conjugated diene copolymer as a main component,
Furthermore, the present invention is a vulcanizable rubber composition containing a hydrogenation unsaturated nitrile-conjugated diene copolymer as a main component, in which a friction reducing agent is added to the composition, which has low friction and excellent wear resistance. Regarding

[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 the rubber composition has excellent properties, and it is also known that the rubber composition obtained by blending the ethylenically unsaturated carboxylic acid metal salt with the copolymer has excellent strength properties. Although this rubber composition has such excellent properties, it has an improper balance between oil resistance and weather resistance, and is therefore used only in limited applications. The present inventor previously examined adding a silicone polymer, a fluororesin or the like as a friction reducing agent in order to reduce the friction of these rubber compositions, but the dispersibility of these additives in the composition However, even if the friction reducing effect is obtained, the strength characteristics of the rubber product are deteriorated. On the other hand, as a method for improving the ozone resistance and sour gasohol resistance (solvent resistance to those rotten with a mixed solution of gasoline and alcohol) of a hydrogenated unsaturated nitrile-conjugated diene copolymer rubber, the copolymer rubber A rubber composition containing a vinyl chloride resin is known (Japanese Patent Publication No. 60-49218).
issue). However, the strength characteristics of this rubber composition are insufficient, and further improvement has been desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention is capable of maintaining the heat resistance, oil resistance, strength characteristics and weather resistance of the above-mentioned conventional nitrile rubber composition while maintaining extrudability, ozone resistance and sour gasohol resistance. A rubber composition having improved dispersibility in a friction reducing agent, and particularly a composition obtained by adding a friction reducing agent as a constituent to the composition, provides a product having a low friction coefficient and thus a small wear amount and a large sliding property. That is the purpose.

[0004]

Means for Solving the Problems As a result of earnest research to solve the above problems, the present inventor has blended a hydrogenated unsaturated nitrile-conjugated diene copolymer with an ethylenically unsaturated carboxylic acid metal salt. A rubber composition containing a vinyl chloride resin in addition to the rubber composition has excellent strength characteristics, ozone resistance, sour gasoline resistance, sour gasohol resistance, extrusion characteristics, and dispersion in a friction reducing agent. Found to increase sex. Further, a product produced from a rubber composition obtained by further mixing the above rubber composition with a silicone rubber or a fluororesin as a friction reducing agent has a low friction property and hence an abrasion resistance while maintaining the physical properties such as the strength property of the rubber. Moreover, they have found that they have excellent slidability, and have completed the present invention based on this finding.
That is, the present invention provides the following first composition and second composition. The first composition of the present invention comprises (1) a hydrogenated unsaturated nitrile-conjugated diene-based copolymer having an iodine value of 120 or less, (2) an ethylenically unsaturated carboxylic acid metal salt, and (3) a vinyl chloride resin. As a rubber composition. The second composition of the present invention comprises (1) a hydrogenated unsaturated nitrile-conjugated diene copolymer having an iodine value of 120 or less, (2) an ethylenically unsaturated carboxylic acid metal salt, (3) a vinyl chloride resin, and (4) A rubber composition containing at least one selected from silicone rubber and fluororesin as a constituent component. The hydrogenated unsaturated nitrile-conjugated diene copolymer used as a constituent of the composition of the present invention is a conjugate of an unsaturated nitrile-conjugated diene copolymer and an unsaturated nitrile-conjugated diene-ethylenically unsaturated monomer copolymer. The double bond portion remaining in the diene unit is hydrogenated, and the hydrogenated nitrile group contained in the copolymer is not used. These are obtained by subjecting the copolymer produced by emulsion polymerization or solution polymerization to a conventional method (for example, Japanese Examined Patent Publication No. 60-58).
No. 242, Japanese Patent Publication No. 62-61045) and the like, the conjugated diene unit portion in the copolymer is hydrogenated, and its iodine value is 120 or less in view of heat resistance. , Preferably 50 or less. 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). .

The unsaturated nitrile constituting the hydrogenated unsaturated nitrile-conjugated diene copolymer used in the composition of the present invention includes acrylonitrile and methacrylonitrile.
Examples of the conjugated diene include 1,3-butadiene, 2,3-dimethylbutadiene, isoprene and 1,3-pentadiene. Examples of the ethylenically unsaturated monomer copolymerizable with these monomers include acrylic acid, methacrylic acid,
Unsaturated carboxylic acids such as itaconic acid, maleic acid; of the above carboxylic acids such as methyl acrylate, butyl acrylate, dimethyl maleate, diethyl fumarate, di-n-butyl fumarate, di-n-butyl itaconic acid Alkyl ester; Alkoxyalkyl ester of unsaturated carboxylic acid such as methoxy acrylate, ethoxyethyl acrylate, methoxyethoxyethyl acrylate; α and β-cyanoethyl acrylate, α, β and γ-cyanopropyl acrylate, cyanobutyl acrylate, cyanooctyl Acrylate having cyanoacryl group such as acrylate; Acrylate having hydroxyalkyl group such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate; Acrylamide, methacryl Amides; N-substituted (meth) acrylamides such as N-methylol (meth) acrylamide, N, N'-dimethylol (meth) acrylamide, N-ethoxymethyl (meth) acrylamide and the like 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-based copolymer used in the composition of the present invention,
Specifically, butadiene-acrylonitrile copolymer rubber (hereinafter abbreviated as NBR), isoprene-butadiene-acrylonitrile copolymer rubber, hydrogenated isoprene-acrylonitrile copolymer rubber, etc .; butadiene-methyl acrylate-acrylonitrile copolymer rubber Examples include hydrogenated butadiene-acrylic acid-acrylonitrile copolymer rubber, butadiene-itaconic acid di-n-butyl-acrylonitrile copolymer rubber, and the like.
The amount of the bound unsaturated nitrile in the copolymer rubber is usually 5 to 60% by weight, preferably 10 to 50% by weight from the requirement of oil resistance.
Is. 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 ethylenically unsaturated carboxylic acid metal salt used as a constituent of the composition of the present invention has a structure in which a metal is ionically bonded to an ethylenically unsaturated carboxylic acid having 1 or 2 or more carboxyl groups and having 5 or less carbon atoms. Anything that has Examples of the ethylenically unsaturated carboxylic acid, acrylic acid, monocarboxylic acid such as methacrylic acid,
Dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid;
Examples thereof include monoethyl maleate and monomethyl itaconate. The metal is not particularly limited as long as it forms a salt with the ethylenically unsaturated carboxylic acid, but usually zinc, magnesium, calcium, barium, titanium, chromium, iron, cobalt, nickel, aluminum,
Tin, lead, etc. can be used. Among them, zinc, magnesium, calcium, and aluminum are suitable due to the characteristics of rubber products. The molar ratio of the ethylenically unsaturated carboxylic acid to the metal is preferably within the range of 1 / 0.5 to 1/3. These ethylenically unsaturated carboxylic acid metal salts may be added to the rubber in the form of a metal salt when a rubber composition is produced by mixing and kneading with other components. And an oxide, hydroxide, or carbonate of the above-mentioned metal may be added, and these may be reacted with each other during an operation such as kneading to generate. The amount of the ethylenically unsaturated carboxylic acid metal salt used is not particularly limited, but is usually 3 to 120 parts by weight, preferably 5 to 100 parts by weight, per 100 parts by weight of the rubber. If the amount is less than 3 parts by weight or more than 120 parts by weight, the strength characteristics of the rubber product are deteriorated, which is not preferable. The vinyl chloride resin used as a constituent of the present invention is a known polyvinyl chloride-containing copolymer of polyvinyl chloride homopolymer and vinyl chloride consisting of 60% by weight or more of vinyl chloride unit and other monomer capable of radical copolymerization. Polymers can be used without particular limitation, for example, vinyl chloride-
A vinyl acetate copolymer, a vinyl chloride graft copolymer with an ethylene-vinyl acetate polymer, a partially crosslinked vinyl chloride resin, or the like can be used. The vinyl chloride resin used in the composition of the present invention may have a degree of polymerization of 200 to 3000, preferably 800 to 1500, and a powder having a small average particle size is convenient because it is convenient for kneading. Can be used. The blending ratio of the vinyl chloride resin used in the present invention is 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. desirable. If the amount of the vinyl chloride resin added is less than 1 part 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 in some cases. The silicone rubber used as a constituent component for reducing friction of the second composition of the present invention has a molecular weight of 200,000 or more, especially 4
A rubber-like material of at least 0,000 is desirable. Various types such as dimethyl type, methyl vinyl type, and methyl phenyl vinyl type are known, and 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 amount of silicone rubber used in the second composition of the present invention is 1 to 30 parts by weight, preferably 1 to 30 parts by weight, per 100 parts by weight of the hydrogenated unsaturated nitrile conjugated diene copolymer.
It is in the range of 20 parts by weight. The amount of silicone rubber added is 3
Even if it is used in an amount of more than 0 parts by weight, there is no friction reducing effect commensurate with the addition, and it is necessary to increase the amount of vinyl chloride resin for maintaining the dispersibility, which limits the range of selection of rubber properties. The roll processability also becomes poor. Further, as the fluororesin used as a constituent component of the second composition of the present invention,
Known fluororesins and the like can be used without particular limitation. For example, polytetrafluoroethylene or a copolymer of tetrafluoroethylene and another copolymerizable monomer, particularly hexafluoropropylene, polychlorotrifluoroethylene. Commercially available fluororesins such as polyvinylidene fluoride and polyvinyl fluoride can be used. The addition amount of the fluororesin used in the second composition of the present invention is 100% by weight of the hydrogenated unsaturated nitrile conjugated diene copolymer.
A range of 1 to 50 parts by weight, preferably 1 to 30 parts by weight per part by weight is suitable. If the amount of the fluororesin added exceeds 50 parts by weight, the strength of the rubber composition will decrease. Further, as the resin, a powdery one can be preferably used because of easy kneading. 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 usually 0.2 per 100 parts by weight of rubber.
It can be used in the range of 10 to 10 parts by weight. In the composition of the present invention, together with the above-mentioned components, zinc white, stearic acid, carbon black, reinforcing agents such as silica,
Various known rubbers commonly used in the rubber industry such as fillers such as talc and calcium carbonate, crosslinking aids such as triallyl isocyanurate and trimethylolpropane, plasticizers, process oils, processing aids and antioxidants. The additives can be appropriately selected and blended and kneaded according to the purpose of use. 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 components in this case is not particularly limited, but after kneading the components such as the ethylenically unsaturated carboxylic acid metal salt and the vinyl chloride resin into the hydrogenated unsaturated nitrile conjugated diene copolymer, It is desirable to mix silicone rubber or fluororesin with this from the viewpoint of uniform mixing and shortening of kneading time.

[0008]

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 7 and Comparative Examples 1 to 3 Hydrogenated acrylonitrile-butadiene copolymer rubbers having an acrylonitrile content of 36% by weight and an iodine value of 28 (hydrogenation rate of 90%) were used to formulate each component shown in Table 1. Therefore, the ethylenically unsaturated carboxylic acid metal salt and vinyl chloride resin components are sequentially added to the rubber component and kneaded with a roll, and then the silicone rubber and the fluororesin are added and kneaded with a roll to form a rubber compounding composition. Manufactured. 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.

[0009]

[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 120μ)] 3) Rhodesil Silicone MM7616 [Rhone Poulean Silicone] 4) Fluon L169 [Asahi Glass Co., Ltd.] 5) Valcup 40KE [Hercules, α, α'-
Bis (t-butylperoxy) -p-diisopropylbenzene] 6) Amine anti-aging agent Naugard 445 [manufactured by Shiraishi Calcium Co.] Further, as a result of testing ozone resistance and gasohol resistance of these rubber compositions, The compositions of Examples to which vinyl chloride was added showed better ozone resistance and gasohol resistance than the compositions of Comparative Examples 1 to 3.

[0011]

EFFECT OF THE INVENTION The first composition of the present invention is a vulcanizate which retains the heat resistance and strength characteristics which are the characteristics of a hydrogenated unsaturated nitrile-conjugated diene copolymer containing an ethylenically unsaturated carboxylic acid metal salt. In addition to providing a product, it has the advantage of providing a vulcanized product with improved oil resistance, weather resistance, and extrudability, and further, the first composition of the present invention is particularly suitable for hydrogenated unsaturated nitrile-conjugated diene systems. It has the advantage of improving the dispersibility of other polymers that are poorly compatible with the copolymer, for example friction modifiers such as silicone. In addition to the advantages of the first composition, the vulcanized product of the second composition of the present invention is excellent in low friction and abrasion resistance and can be applied to a wide range of applications. For example, the main applications thereof are hoses, seals, rolls and the like, as well as sliding parts such as glass runs and wipers of automobiles.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 27/12 LGB 9166-4J LGE 9166-4J 83/04 LRT 8319-4J LRY 8319-4J

Claims (2)

[Claims] 1. A hydrogenated unsaturated nitrile-conjugated diene copolymer having an iodine value of 120 or less, (2) an ethylenically unsaturated carboxylic acid metal salt, and (3) a vinyl chloride resin as constituent components. A rubber composition comprising: 2. (1) Hydrogenated unsaturated nitrile-conjugated diene copolymer having an iodine value of 120 or less, (2) ethylenically unsaturated carboxylic acid metal salt, (3) vinyl chloride resin and (4) silicone. At least 1 selected from rubber and fluororesin
A rubber composition comprising a seed as a constituent.