JPH0455105B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for providing a highly durable and inexpensive composite. More specifically, highly durable fluorine elastomer is placed on the surface where durability is most required.
In order to provide an inexpensive composite with substantially excellent durability by disposing a relatively inexpensive and durable acrylic elastomer thereon, dialkyl peroxide or peroxyketal is used as a vulcanizing agent for the fluorine-based elastomer. Fluorine-based elastomer
Using 0.5 parts by weight or more and 10 parts by weight or less of trimethylolpropane trimethacrylate per 100 parts by weight,
This invention relates to a method for improving the adhesive strength at the interface of a composite by using a dialkyl peroxide as a vulcanizing agent for an acrylic elastomer. Composite materials obtained by this method, such as composite hoses in which the outer tube is made of fluorine-based elastomer and the inner tube is made of acrylic elastomer, provide radiator hoses etc. that are durable against radiant heat around the engine, and A composite hose with a tube made of fluorine-based elastomer and an outer tube made of acrylic elastomer has an inner tube that contains fluids that impair the durability of rubber materials other than fluorine-based elastomer, such as high-temperature engine oil, high-temperature air, high-temperature gas, or The present invention provides a hose suitable for passage of swellable liquids, gases, and mist. (Prior Art) Conventionally, for rubber parts that come into contact with high-temperature fluids, a single rubber material that does not lose its durability even when it comes into contact with the fluid has been selected and used. For example, lubricating oil hoses use nitrile rubber (NBR), which has excellent oil resistance, and automobile radiator hoses use ethylene and propylene-based elastomers (EPR), which have excellent antifreeze and heat resistance.
has been used. However, due to various technological innovations in recent years, the temperature inside the engine compartment of a car is on the rise.
Nitrile rubber has insufficient durability as a lubricating oil hose, and acrylic elastomer, which is more durable, has been used. However, it has been pointed out that acrylic elastomers also have reduced durability due to various additives in engine oil. Additionally, materials with higher heat resistance are attracting attention for radiator hoses due to the radiant heat from surrounding heat sources. Therefore, in order to solve the above problems and improve the reliability of rubber parts, it is easy to consider using highly durable fluorine-based elastomers, but fluorine-based elastomers have poor cold resistance and are expensive. Therefore, it cannot be said to be a perfect material, and is particularly unsuitable for automobile parts that require both cost and reliability. Therefore, the next best method is to coat only the areas where durability is a real issue with conventional materials with fluorine-based elastomer to substantially increase durability. . (Problems to be Solved by the Invention) However, when covering an acrylic elastomer with a fluorine-based elastomer, the interfacial strength of the adhesion between the two is low, and the reliability of the composite is impaired. In order to obtain a durable and inexpensive composite, it is extremely important to improve the adhesive strength between the two. (Means for Solving the Problems) Therefore, the inventors endeavored to improve the adhesive strength between the fluorine-based elastomer and acrylic elastomer in order to obtain a composite of the fluorine-based elastomer and acrylic elastomer that is inexpensive and has substantial durability. Dialkyl peroxide or peroxyketal as a vulcanizing agent for fluorine-based elastomer and per 100 parts by weight of fluorine-based elastomer
By using 0.5 parts by weight or more and 10 parts by weight or less of trimethylolpropane trimethacrylate and dialkyl peroxide or peroxyketal as a vulcanizing agent for the acrylic elastomer, the adhesive strength between the fluorine-based elastomer and the acrylic elastomer can be improved. As a result, we were able to obtain an inexpensive, durable, and highly reliable composite. Acrylic elastomer is an elastomer containing acrylic acid ester as one of its main components, and is currently commercially available as a heat-resistant and durable material under the trade name VAMAC (DuPont) JSR.
AR (Japan Synthetic Rubber Co., Ltd.), Nitzpol AR (Nippon Zeon Co., Ltd.), Noxtite (Japan Oil Seal Co., Ltd.),
Examples include Toracron (Toa Paint Co., Ltd.) and Denka ER (electrochemical). Fluorine-based elastomer refers to a copolymer of fluorocarbon and hydrocarbon, and JSR Aflas (Japan Synthetic Rubber Co., Ltd.) is commercially available. The dialkyl peroxides used in the present invention are those normally used for crosslinking hydrocarbons, such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α
-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-
2,5-di(t-butylperoxy)hexyne-
3, and 1.1 as peroxyketal.
-bis(t-butylperoxy)-3,3,5-
Trimethylcyclohexane, n-butyl-4,4
-bis(t-butylperoxy)valerate,
2,2-bis(t-butylperoxy)butane,
2,2-bis(t-butylperoxy)octane is mentioned. Trimethylolpropane trimethacrylate added to the fluorine-containing elastomer is preferably 0.5 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the fluorine-containing elastomer; if it is less than 0.5 parts by weight, sufficient adhesive strength cannot be obtained, and 10 parts by weight If the adhesive strength exceeds 100%, the adhesive strength may deteriorate or the elasticity of the fluorine-containing elastomer vulcanizate itself may be lost, which is not preferable. Trimethylolpropane trimethacrylate can be used in combination with or as a partial substitute for triallyl isocyanurate, triallyl cyanurate, and triallyl trimellitate, which are commonly used as vulcanizing agents for fluorine-based elastomers. . It is obvious from the gist of the present invention that the amount of peroxide used must be sufficient for the elastomer itself to exhibit the desired practical performance for both the fluorine-based elastomer and the acrylic elastomer. The effect of the present invention is expressed depending on the amount added. Compounds of fluorine-based elastomers and acrylic elastomers can be prepared by any method commonly used in the rubber industry, and open roll or internal mixers are usually used. Furthermore, it is of course possible to add various compounding agents to individual vulcanizates for the purpose of providing desired performance. Common methods for obtaining the desired composite include bonding using a calendar and compositing using an extruder. Vulcanization of the composite is not subject to any limitations other than the required time and temperature to achieve sufficient crosslinking, depending on the half-life of the peroxide used. A preferred method for obtaining a stable vulcanizate is to heat-treat the primary vulcanizate in an air oven if necessary and then perform vulcanization. The method of the present invention uses a fluorine-based elastomer as an outer tube,
A radiator hose with an inner tube made of acrylic elastomer that is more durable than EPR hoses.
An acrylic rubber hose with an inner tube made of fluorine-based elastomer and an outer tube made of acrylic elastomer,
This provides an effective means for obtaining a lubricating oil hose that is more durable than an NBR hose, and a heater hose that is more durable than an EPR hose. (Example) The effectiveness of the present invention will be explained below using examples. Examples 1 to 5 Comparative Examples 1 to 2 JSR Aflas (manufactured by Japan Synthetic Rubber Co., Ltd.) was used as the fluorine-based elastomer and the following acrylic ester copolymer was used as the acrylic elastomer.
A compound was prepared using an 8-inch roll according to the compounding procedure shown in 1, sheeted, and both unvulcanized rubber sheets were laminated together, followed by press vulcanization at 150° C. for 30 minutes.
After vulcanization in an air oven at 150℃ for 8 hours,
A vulcanizate was produced. The adhesive strength of the composite and the physical properties of each elastomer were measured in accordance with JIS/K6301. The acrylic ester copolymer used was produced as follows. That is, 43 kg of water, 11 kg of vinyl acetate, and each of electrified Poval B-05 and B-17 as polyvinyl alcohol were placed in an autoclave.
700g, sodium acetate 60g, ferric sulfate 2g,
4 g of ethylenediaminetetraacetic acid and 90 g of co-catalyst were added and mixed with stirring, and the internal temperature of the autoclave was brought to 45°C. The air in the upper part of the autoclave was replaced with nitrogen, and then ethylene was introduced under pressure to bring the ethylene pressure to 50 kg/cm ² . Separately, an aqueous polymerization initiator solution, 10 kg of n-butyl acrylate, and 7 kg of ethyl acrylate were injected through an injection port to allow polymerization to proceed, and the injection was completed in 12 hours. An aqueous solution of Glauber's salt was added to the produced polymer emulsion to solidify the polymer, which was washed with water, dehydrated and dried, and the resulting polymer was used as an acrylic ester copolymer for testing. As shown in Table 1, the system using peroxyketal or dialkyl peroxide exhibits sufficient adhesive strength compared to the system using peroxyester or the system not using trimethylolpropane trimethacrylate. There is.

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Claims (1)

[Claims] 1 When producing a composite consisting of two layers of acrylic elastomer and fluorine-based elastomer, dialkyl peroxide or peroxyketal is used as the vulcanizing agent for the acrylic elastomer, and dialkyl peroxide or peroxyketal is used as the vulcanizing agent for the fluorine-based elastomer. Production of a composite with improved adhesion at the composite interface, characterized in that 0.5 parts by weight or more and 10 parts by weight or less of trimethylolpropane trimethacrylate are used per 100 parts by weight of oxide or peroxyketal and fluorine-based elastomer. Method.