JPH06107879A - Adhesive rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition excellent in oil resistance, ozone resistance, flame retardancy, and vulcanization adhesion to metals, e.g. brass, by mixing a chlorinated ethylene/alpha-olefin copolymer rubber, a specific compound, and S. CONSTITUTION:The composition comprises a chlorinated ethylene/alpha-olefin copolymer rubber (e.g. Miprene XM-01, manufactured by Mitsui Petrochemical Industries, Ltd.), a dicycloamine salt (e.g. dicyclohexylamine salt) of 2,4,6- trimercapto-1,3,5-triazine, and S. It preferably further contains dicyclohexylamine salt of 2-mercaptobenzothiazole.

Description

Detailed Description of the Invention

[0001]

The present invention relates to oil resistance, ozone resistance,
The present invention relates to an adhesive rubber composition which is flame-retardant and has excellent vulcanization adhesion to metals such as brass.

[0002]

2. Description of the Related Art The performance required for the outer layer rubber of oil-resistant hoses and high-pressure hoses includes oil resistance, ozone resistance, and flame retardancy. In such hoses, the reinforcing layer is brass plated wire or the like. Since it is often composed of, the vulcanization adhesion with metals such as brass is also important.

Therefore, conventionally, a CR rubber (chloroprene rubber) which is excellent in oil resistance and flame retardancy and which is vulcanized and adhered to a metal, as an outer layer rubber of an oil resistant hose or a high pressure hose,
EPDM rubbers which are excellent in ozone resistance and which are vulcanized and adhered to a metal have been generally used.

However, the CR type rubber has a drawback that it is inferior in ozone resistance, while the EPDM type rubber is inferior in oil resistance and flame retardancy.

Recently, a chlorinated ethylene / α-olefin copolymer rubber has been developed as a rubber material having excellent oil resistance, ozone resistance and flame retardancy. A vulcanization system of chlorinated ethylene / α-olefin copolymer rubber is disclosed in Japanese Patent Application Laid-Open No. HEI-2.
It is proposed in Japanese Patent Publication No. 196843 and the like. As an example, a vulcanization system composed of a triazine compound and a pipediline salt of benzoic acid has been proposed.

However, the chlorinated ethylene / α-olefin copolymer rubber vulcanization systems proposed so far are all
It was inferior in vulcanization adhesion to brass. for that reason,
The chlorinated ethylene / α-olefin copolymer rubber could not be used as an outer layer of an oil resistant hose or a high pressure hose constituting a reinforcing layer with a brass plated wire.

[0007]

The present invention has been made in view of the above facts, and is a rubber material having excellent oil resistance, ozone resistance and flame retardancy, that is, chlorinated ethylene / α-.
An object of the present invention is to provide an adhesive rubber composition containing an olefin copolymer rubber as a main component and having excellent vulcanization adhesiveness to a metal such as brass.

As a result of intensive studies to achieve the above object, the present inventors have found that 2,4,6-trimercapto is used as a vulcanization system for chlorinated ethylene / α-olefin copolymer rubber (A). In vulcanization adhesion to brass when a vulcanization system consisting of dicycloamine salt of -1,3,5-triazine (TDCA), dicyclohexylamine salt of 2-mercaptobenzothiazole (abbreviation: MDCA) and sulfur is used. It was found that the present invention was extremely excellent, and the present invention was completed.

[0009]

The object of the present invention is thus to provide a chlorinated ethylene / α-olefin copolymer rubber (A),
A rubber composition containing a dicycloamine salt of 2,4,6-trimercapto-1,3,5-triazine (TDCA) (B) and sulfur (D), or chlorinated ethylene.
α-olefin copolymer rubber (A), dicycloamine salt of 2,4,6-trimercapto-1,3,5-triazine (TDCA) (B), dicyclohexylamine salt of 2-mercaptobenzothiazole (abbreviation: MDCA) (C)
And an adhesive rubber composition containing sulfur (D) and a vulcanized product obtained by vulcanizing them.

[0010]

[Structure] The structure of the present invention will be specifically described below, but more preferable embodiments and advantages based thereon will become apparent.

Adhesive Rubber Composition [Chlorinated Ethylene / α-Olefin Copolymer Rubber (A)] The copolymer rubber (A) used in the present invention is ethylene and at least one C _{3 to} C ₁₀ α-olefin. It is obtained by substituting a part of hydrogen atoms of the copolymer rubber with and chlorine atoms.
Of course, it does not matter if a small amount of a diene monomer such as dicyclopentadiene or ethylidene norbornene is copolymerized.

As chlorinated ethylene / α-olefin copolymer rubbers (A), various grades of α-olefin monomers constituting the same, various grades having different monomer ratios, molecular weights, chlorine contents and the like are known. , In the present invention,
Any grade may be used. Specific examples of the C ₃ -C ₁₀ α-olefin monomer constituting it include propylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene.
Propylene and 1-butene are particularly preferred. The molar ratio of ethylene unit to α-olefin unit is 50/50 to 95/5.
Is preferable, and the rubbery property is excellent in this range. The chlorine content is 5 to 45% by weight, and further 20 to 40%.
Weight% is preferable. Copolymer rubbers having a chlorine content in this range retain the flexibility like rubber and have excellent oil resistance. The vulcanization rate is also in a practical range.

Further, as the chlorinated ethylene / α-olefin copolymer rubber (A), ethylene / α before chlorination is used.
-Intrinsic viscosity [η] (135 ° C in decalin) measured on olefin-based copolymer rubber is 0.6 to 6 dl / g
Is preferred, and that of 1 to 4 dl / g is more preferred. The intrinsic viscosity [η] is an index of the molecular weight of rubber, and within the above range, the balance between strength characteristics and processability is good.

[Vulcanization System] A component in the rubber composition of the present invention, which contributes to vulcanization, is a dicycloamine salt of 2,4,6-trimercapto-1,3,5-triazine (TDCA). ) (B), dicyclohexylamine salt of 2-mercaptobenzothiazole (abbreviation: MDCA) (C)
And sulfur (D). The rubber composition of the present invention may be composed of (B) and (D) in addition to the above (A).
The dicycloamine salt of 2,4,6-trimercapto-1,3,5-triazine (TDCA) (B) is a compound represented by the following chemical formula (1).

[0015]

[Chemical 1]

The dicyclohexylamine salt of 2-mercaptobenzothiazole (C) (MDCA) is a compound represented by the following chemical formula 2.

[0017]

[Chemical 2]

In the present invention, TDCA (B) is a vulcanizing agent, M
DCA (C) acts synergistically as a vulcanization accelerator. Sulfur (D) contributes to improving the adhesiveness between the rubber composition and a metal such as brass.

As the sulfur (D) used in the present invention, powder sulfur, highly dispersible sulfur, insoluble sulfur and the like which are generally used as a vulcanizing agent for rubber can be used.

The vulcanizing components (B), (C),
(D) acts synergistically to contribute to the improvement of vulcanization adhesion of the rubber composition of the present invention to a metal such as brass.

T based on 100 parts by weight of the copolymer rubber (A)
It is extremely preferable that the following conditions (1) to (3) are satisfied when the amount of DCA (B) is x parts by weight and the amount of MDCA (C) is y parts by weight. y ≧ −x + 1 (1) y ≦ −3.3x + 6.5 (2) 0.25 ≦ x ≦ 2.0 (3) By satisfying the above conditions (1) to (3), 10
Moreover 0% modulus (M _{10 0)} of 20 kgf / cm ² or more can be adhesion to brass-plated wire and 10 kgf / 25 cm or more. That is, it is possible to keep the elastic modulus of the vulcanized product high and obtain an excellent vulcanizing adhesion to brass.

The compounding amount of sulfur is usually 10 g of the copolymer rubber (A).
It is usually preferable to add 0.2 to 10 parts by weight to 0 part by weight. Within this range, the elastic modulus, vulcanization adhesiveness and heat resistance of the vulcanizate can be compatible.

In the rubber composition of the present invention, if necessary, compounding agents such as commonly used acid-accepting agents such as magnesia, fillers, reinforcing agents, plasticizers, antiaging agents, processing aids and the like are blended and kneaded. You may.

The rubber composition of the present invention can be applied to many rubber products such as tires, belts, molds, rolls and hoses, which are used outdoors for a long time and require oil resistance. it can.

[Vulcanized Product] To obtain a vulcanized product (vulcanized rubber product) from the rubber composition of the present invention, a method known per se can be adopted. That is, by melt-kneading each of the above-mentioned compounds, an unvulcanized compound is once prepared, and the compound is once molded into a desired shape and then heated and vulcanized at a temperature of 130 to 200 ° C. A vulcanized product can be obtained by heating and vulcanizing at the above temperature at the same time as molding into a shape.

Since the rubber composition of the present invention has excellent vulcanization adhesion to brass, it is useful in the field where a brass body and a vulcanized product are integrated into a product.

Here, the brass body is used as a reinforcing material for ordinary rubber products, and means a wire material, a pipe material, a plate material, a steel material or the like, and may be brass-plated.

Particularly, the vulcanized product of the present invention is suitable for the outer layer rubber of a heat-resistant high-pressure hose having a pressure-resistant steel wire layer plated with brass and an oil-resistant hose. At that time, it is preferable to use an NBR-based rubber composition having excellent oil resistance as the inner rubber layer.

[Rubber Hose] An example in which the vulcanized product of the present invention is applied to a rubber hose will be described.

In FIG. 1, an inner pipe 1, a reinforcing layer 2 and an outer pipe 3 are provided, and the outer pipe 3 is formed of a vulcanized product of the rubber composition of the present invention. The inner pipe 1 is in direct contact with a fluid such as a liquid such as gasoline that moves in the hose, and a vulcanized product of NBR or the like is preferably used. Of course, it may be a vulcanized product of the rubber composition of the present invention.

The reinforcing layer 2 is in close contact with the inner pipe 1 and also in close contact with the outer pipe 3, and is a metal layer such as brass or brass-plated steel wire. The outer tube 3 is in close contact with the reinforcing layer 2, prevents damage to the inner tube 1 and the reinforcing layer 2 due to impact, heat, etc., and can fix the reinforcing layer 2. The outer tube 3 is made of a vulcanized product of the rubber composition of the present invention and strongly adheres to the reinforcing layer. The rubber hose having such a structure can be manufactured by a process known per se. The structure of the rubber hose is not limited to this example, and for example, a plurality of reinforcing layers may be used. INDUSTRIAL APPLICABILITY The rubber hose of the present invention is excellent in oil resistance, ozone resistance, and flame retardancy, and has an outer tube in close contact with the reinforcing layer, and thus is useful as a highly durable high pressure hose.

[0032]

EXAMPLES The present invention will be specifically described below based on examples.

(Examples 1 and 2 and Conventional Examples 1 and 2): Comparison between the outer layer rubber of the current oil resistant hose and the vulcanized rubber of the rubber composition of the present invention. With a press molding machine, 1
It was vulcanized under conditions of 65 ° C. for 30 minutes and tested for oil resistance, ozone resistance and flame retardancy. Results are in Table A
It was shown to.

[Test Method] 1. Oil resistance test A vulcanized sample was added to JIS # 1 test oil at 100 ° C for 70%.
It was immersed for a period of time, and the capacity change (ΔVC) before and after the immersion was measured. 2. Ozone resistance test Using a static ozone tester, the vulcanized sample was placed in a state where the ozone concentration was 100 pphm, the temperature was 50 ° C, and the elongation rate was 40%.
Exposed for hours. After 168 hours, no cracks were generated ◎,
The occurrence of cracks after 168 hours was evaluated as Δ, and the case where the sample was cut due to cracks after 168 hours was evaluated as ×. 3. Flame Retardancy Test The flammability of the vulcanized sample was measured according to JIS K7201 B method No. 1 and indicated by oxygen index.

[Results] As is clear from Table A, the vulcanized rubber of the rubber composition of the present invention using the chlorinated ethylene / α-olefin copolymer rubber has oil resistance, ozone resistance and flame retardancy. However, conventional CR-based or EPDM-based vulcanized rubbers could not satisfy all of the oil resistance, ozone resistance, and flame retardancy.

(Explanation of components in Table A) * 1 Mitsui Petrochemical Co., Ltd., Maiprene XM-01 chlorine content: 27 wt% * 2 Mitsui Petrochemical Co., Ltd., Myprene XM-38 chlorine content: 35 wt% * 3 Denka chloroprene S- manufactured by Denki Kagaku Kogyo
40 * 4 Mitsui Petrochemical Industry Co., Ltd., Mitsui EPT 4070 * 5 Showa Denko KK, 2,4,6-Trimercapto-
Dicycloloamine salt of 1,3,5-triazine * 6 Showa Denko's dicyclohexylamine salt of 2-mercaptobenzothiazole

[0037]

[Table 1]

(Examples 3 to 15, Conventional Examples 3 to 4 and Comparative Examples 1 to 10): Comparison of Vulcanization Systems in Chlorinated Ethylene / α-Olefin Copolymer Rubber Compositions A sample was prepared as shown in the test method column. Tensile strength (T _B ),
Elongation (E _B ) and tensile stress (M ₁₀₀ ) and adhesion strength were calculated. The results are shown in Table B. Moreover, in FIG.
A graph for the compounding amount x of A (B) and the compounding amount y of MDCA (C) is shown.

[Test Method] 1. Tensile test A rubber composition is prepared and mixed with a mixing roll at 60 ° C. for 15 minutes, and then with a small lab roll.
Sheets were taken out to a thickness of 0 mm. This sheet rubber was pressure-vulcanized with a lab press molding machine at a surface pressure of 30 kgf / cm ² under conditions of 165 ° C. and 30 minutes. This is JI
T _B , E _B and M ₁₀₀ were measured and calculated using a tensile tester specified by SK6301 at a tensile speed of 500 mm / min. In addition, all measurement methods and calculations are in accordance with JIS K6301 3. It was conducted according to the method described in the tensile test. 2. Peeling (vulcanization adhesion with brass) test Prepare a rubber composition, mix with a mixing roll at 60 ° C for 15 minutes, and then with a small lab roll.
The sheet was taken out to a thickness of 5 mm. Then, a rubber sheet having a thickness of 2.5 mm was pressed onto a brass plate. However, cellophane paper was placed on the part to be gripped by the chuck during peeling so that the upper and lower layers would not adhere to each other. Using a laboratory press molding machine, the surface pressure is 30 kg at 165 ° C for 30 minutes.
It was pressure-vulcanized at f / cm ² and molded and integrated. After leaving at room temperature for 24 hours, the molded and integrated sample is 2.54 cm (1 i
It was cut into nch) width and subjected to a peel test. The peeling force was measured in accordance with the method described in JIS K6301 8.3, which peels rubber adhered to a metal piece in the direction of 90 degrees, using a tensile tester specified in JIS K6301 and a pulling speed of 50 mm. / min. Then, the adhesion strength was calculated.

[Results] As is clear from Table B, when vulcanizing the chlorinated ethylene / α-olefin copolymer rubber, according to the vulcanization system adopted in the rubber composition of the present invention, brass is used. Although it is a vulcanized rubber with excellent vulcanization adhesiveness with, the conventionally used vulcanization system does not vulcanize and adhere to brass.

(Explanation of ingredients in Table B) * 1 Triallyl isocyanurate manufactured by Nippon Kasei Co., Ltd. * 2 Trimellitic acid ester (plasticizer) manufactured by Adeka Argus Chemical Co., Ltd. * 3 Distearyl manufactured by Lion Akzo Dimethylammonium chloride * 4 Yoshitomi Pharmaceutical, organic amine compound * 5 Kayaku Akzo, di-t-butylperoxydiisopropylbenzene Effective content 40%

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

The adhesive rubber composition of the present invention has excellent vulcanization adhesiveness to metals such as brass, and the resulting vulcanizate is essentially the oil resistance of chlorinated ethylene / α-olefin copolymer rubber vulcanizates. Excellent in resistance, ozone resistance and flame retardancy. An excellent rubber hose can be obtained by using a vulcanized product of the above rubber composition for the outer tube of the hose having a brass-plated wire as a reinforcing layer.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a rubber hose of the present invention.

FIG. 2 is a diagram showing the relationship between the blended amount of TDCA (B) and the blended amount of MDCA (C).

Claims (3)

[Claims] 1. A chlorinated ethylene / α-olefin copolymer rubber (A), 2,4,6-trimercapto-1,3,5-
A rubber composition containing a dicycloamine salt of triazine (TDCA) (B) and sulfur (D). 2. A chlorinated ethylene / α-olefin copolymer rubber (A), 2,4,6-trimercapto-1,3,5-
Dicycloamine salt of triazine (TDCA) (B), 2
An adhesive rubber composition containing a dicyclohexylamine salt of mercaptobenzothiazole (abbreviation: MDCA) (C) and sulfur (D). 3. T based on 100 parts by weight of the copolymer rubber (A).
The adhesive rubber composition according to claim 1, wherein the following conditions (1) to (3) are satisfied when the blending amount of DCA (B) is x parts by weight and the blending amount of MDCA (C) is y parts by weight. y ≧ −x + 1 (1) y ≦ −3.3x + 6.5 (2) 0.25 ≦ x ≦ 2.0 (3)