JPH06102756B2 - Rubber composition with excellent adhesion to fluororubber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an epichlorohydrin-based rubber composition having excellent adhesion to fluororubber.

(Prior Art) Conventionally, an acrylonitrile-butadiene copolymer rubber (NBR) has been used as a hose for fuel oil such as gasoline. As a result of the recent rise in engine room temperature and exhaust gas recycling through the implementation of exhaust emission control measures and energy saving measures, it is possible to have aging resistance, weather resistance, acid rotten gasoline resistance, etc. as rubber materials used. It has come to be required, and it has been found that the NBR is not sufficient as a material satisfying such various required performances. Fluorine rubber is mentioned as a rubber material that meets the above requirements, but the price is 10% that of ordinary rubber.
When used as a fuel oil hose because it is as high as ~ 20 times and has a problem with cold resistance, it is used as a multi-layer rubber hose with a thin layer of fluororubber as the inner layer and another type of rubber such as epichlorohydrin-based rubber as the outer layer. Is gradually increasing.

(Problems to be Solved by the Invention) In the case of a multilayer rubber hose, the adhesiveness between these different rubbers is the most important problem. In the case of the above-mentioned fluororubber and epichlorohydrin type rubber, it is generally known that the adhesiveness is poor, and therefore, a means of incorporating a certain kind of additive into the rubber is usually adopted. The applicant has blended epichlorohydrin rubber with a compound selected from calcium hydroxide, an epoxy compound and aldehyde amines, aldehyde ammonias, 1,8-diazabicyclo (5,4,0) undecene-7 or a weak acid salt thereof. , A composition having excellent adhesiveness with fluororubber has already been proposed (Japanese Patent Publication No. 61-29629). The present invention provides an epichlorohydrin-based rubber composition which is further improved from this composition and has excellent adhesion to fluororubber.

(Means for Solving the Problems) The present invention relates to 100 parts by weight of epichlorohydrin rubber, 0.5 to 30 parts by weight of calcium hydroxide, 1,8-diazabicyclo (5,4,0) undecene-7 or a weak acid salt thereof. 0.1 ~
A rubber composition having excellent adhesiveness to fluororubber, which is characterized by containing 5 parts by weight, 0.1 to 8 parts by weight of a phenolic resin and 0.1 to 10 parts by weight of an epoxy compound.

The epichlorohydrin-based rubber used in the present invention is selected from epichlorohydrin homopolymer, epichlorohydrin-allyl glycidyl ether binary copolymer, epichlorohydrin-ethylene oxide binary copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer. In the case of a copolymer rubber, its composition ratio (mol) is 85 to 99: 1 in the case of an epichlorohydrin-allyl glycidyl ether binary copolymer.
5 to 1, 20 to 80:80 to 20 for epichlorohydrin-ethylene oxide binary copolymer, epichlorohydrin-
In the case of an ethylene oxide-allyl glycidyl ether terpolymer, those of 20 to 79:79 to 20: 1 to 20 are preferable.
These rubbers may be used alone or in a mixture.

The calcium hydroxide used in the present invention is 10
0 mesh pass 95% or more fine powder is preferable,
Compounding amount is 100 parts by weight of epichlorohydrin rubber
The amount is 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight. If the blending amount is less than 0.5 parts by weight, the effect of improving the adhesiveness will not be obtained, and if it exceeds 30 parts by weight, the mechanical properties of the vulcanized product will be impaired, such being undesirable.

The composition of the present invention contains 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter abbreviated as DBU) or its weak acid salt. Although DBU may be used as such, it can be used as a weak acid salt such as a carbonate, a long-chain aliphatic carboxylic acid salt, a phenol salt, or a salt with a thiol in view of its handling. Typical DBU salts include DBU-carbonate, DBU-stearate, DBU-2-ethylhexylate, DBU-benzoate, DBU-naphthoate, DBU-phenol salt, DBU-2-mercaptobenzoate. Examples thereof include thiazole salts. The compounding amount of the weak acid salt of DBU or DBU is 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, based on 100 parts by weight of epichlorohydrin rubber. If the blending amount is less than 0.1 part by weight, the sufficient effect on the adhesiveness with the fluororubber cannot be obtained. On the other hand, if the compounding amount exceeds 5 parts by weight, the vulcanization rate of the epichlorohydrin-based rubber becomes too fast, which causes difficulty in processing.

The phenolic resin used in the present invention may be a commercially available one, for example, phenol, cresol, xylenol, alkylphenol, phenylphenol,
Phenol compounds such as resorcin and formaldehyde,
Examples include resins obtained by condensation reaction with acetaldehyde, paraformaldehyde, furfural, etc., and modified resins with terpenes, cashews, etc., which usually have a softening point of 13
Those having a temperature of 0 ° C or lower, preferably 60 to 130 ° C are used. 13
If the temperature exceeds 0 ° C, there is a problem in dispersibility during mixing. It is particularly preferable in terms of handling to mix it with the above-mentioned DBU at the time of compounding, and the adhesiveness with the fluororubber is further improved. The amount of the phenolic resin compounded is 0.1 to 8 parts by weight, preferably 0.2, based on 100 parts by weight of the epichlorohydrin rubber.
~ 5 parts by weight. If the blending amount is less than 0.1 parts by weight, sufficient adhesive force cannot be obtained, and if it exceeds 8 parts by weight, it is not particularly effective for improving the effect of the present invention.

As the epoxy compound of the present invention, a generally known one is used. Examples thereof include bisphenol A type epoxy resin, resorcin type epoxy resin, tetrahydroxyphenylethane type epoxy resin, novolac type epoxy resin, glycidyl ether type compound of ethylene oxide polymer or propylene oxide polymer, glycidyl ether type compound of polyhydric alcohol, and the like. be able to. The compounding amount of the epoxy compound is 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of epichlorohydrin rubber.
5 parts by weight. If the compounding amount is less than 0.1 part by weight, sufficient adhesive force cannot be obtained, and if it exceeds 10 gravitational parts, the vulcanization rate is remarkably reduced, and its physical properties as an epichlorohydrin-based rubber cured product can be sufficiently exhibited. Disappear.

As the vulcanizing agent for vulcanizing the composition of the present invention, any of those usually used for epichlorohydrin-based rubber may be used,
For example, sulfur-based vulcanizing agents, peroxide-based vulcanizing agents that utilize the unsaturated bond of the allyl glycidyl ether component of rubber,
There are vulcanizing agents such as diamine vulcanizing agents, polythiols, and thioureas that utilize chlorine in rubber. Above all, the use of thioureas such as 2-mercaptoimidazoline is effective in terms of the balance of vulcanization rate and vulcanization physical properties. Particularly preferred. The appropriate amount of these vulcanizing agents to be compounded is 0.2 to 10 parts by weight per 100 parts by weight of epichlorohydrin rubber.

In the composition of the present invention, in addition to the above components, if necessary, a vulcanization accelerator, a vulcanization retarder, an acid acceptor, a reinforcing material, a filler, a plasticizer, a lubricant, an antioxidant, a pigment, a flame retardant, etc. Compounding agents commonly used in the art can be added. In particular, the addition of a metal compound serving as an acid acceptor is particularly effective from the viewpoint of the thermal stability of the composition of the present invention. Examples of the above metal compounds include oxides, hydroxides, carbonates, carboxylates, silicates, borates, phosphites of Group II metals of the periodic table, IV of the periodic table.
There are group a metal oxides, basic carbonates, basic carboxylates, basic phosphites, basic sulfites, tribasic sulfates and the like. Specific examples of these include magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate,
Barium carbonate, quicklime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, calcium phthalate, magnesium phosphite, calcium phosphite, zinc white, tin oxide, litharge, red lead, lead white, dibasic phthalic acid Examples thereof include lead, dibasic lead carbonate, tin stearate, basic lead phosphite, and basic lead sulfite.
The compounding amount of these acid acceptors is 100% epichlorohydrin rubber.
A suitable range is 0.5 to 20 parts by weight with respect to parts by weight.

The composition of the present invention is mixed using an ordinary mixer such as a roll, a pressure kneader, or a Banbury mixer, and vulcanization is performed by pressure heat molding using a mold, steam, microwave, hot air oven, salt bath. It can be performed by various ordinary vulcanization methods such as vulcanization.

A highly fluorinated elastic copolymer is suitable as the fluororubber to which the composition of the present invention is applied. For example, a copolymer of vinylidene fluoride and another copolymerizable fluorine-containing olefin can be mentioned. Examples of fluorine-containing olefins include hexafluoropropene, pentafluoropropene, trifluoroethene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, etc. One or two of these The above is used as a copolymerization component. Preferred copolymers include vinylidene fluoride-hexafluoropropene binary copolymer and vinylidene fluoride-tetrafluoroethylene-hexafluoropropene ternary copolymer. A known compounding agent such as a vulcanizing agent, a vulcanization accelerator, a stabilizer, a colorant, a plasticizer, and a reinforcing agent is added to the fluororubber depending on its purpose.

The method of adhering the composition of the present invention and the fluororubber can be carried out by laminating both and heating and vulcanizing at the same time, or by heat-vulcanizing one weakly so as not to lose its shape and then laminating both and sufficiently heating and vulcanizing. The method can be adopted.

(Examples) Examples 1 to 4 Comparative Examples 1 to 7 The epichlorohydrin-based rubber compositions shown in Table 1 were used.
Kneading with an inch roll at 70-80 ℃ for 15-20 minutes and thickness 1-
Sheet A of 1.5 mm was obtained.

On the other hand, the fluororubber composition shown in Table 2 was similarly kneaded to prepare a sheet B having a thickness of 1 to 1.5 mm.

The above-mentioned sheet A and sheet B are stuck together, and the temperature is 160 ° C, 20 to 2
It was pressed at 5 kg / cm ² for 30 minutes to obtain a laminated sheet having a thickness of 2 to 2.3 mm. This laminated sheet was cut into a strip of 2.5 × 10 cm to prepare a test piece, and the test piece was subjected to a T-peel test under a tensile condition of 25 ° C. and 50 mm / min, and the results are shown in Table 3.

As is clear from the results in Table 3, the laminated sheet using the composition of the present invention does not cause peeling of the rubber on the adhesive surface even after immersion in warm fuel oil or after heat aging. On the other hand, Comparative Example 1 lacking the phenolic resin in the composition of the present invention,
Comparative Example 2 lacking DBU or its weak acid salt and Comparative Example 3 lacking an epoxy compound both cause interfacial debonding at the adhesive surface with low tensile strength after immersion in hot fuel oil or after heat aging.

(Effects of the Invention) The composition of the present invention has very excellent adhesion to fluororubber, and the adhesive interface is strong even after immersion in hot fuel oil for a long time or after aging for a long time by heating. Therefore, it is extremely suitable for applications such as a fuel hose whose inner surface is made of fluororubber which has excellent physical properties such as acid rotting gasoline resistance and whose outer surface is made of epichlorohydrin type rubber which has excellent aging resistance, weather resistance and gasoline resistance. It is valid.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 63:00)

Claims (1)

[Claims] 1. 100 parts by weight of epichlorohydrin rubber, 0.5 to 30 parts by weight of calcium hydroxide, 1,8-diazabicyclo (5,4,0) undecene-7 or its weak acid salt of 0.1 to
A rubber composition having excellent adhesiveness to fluororubber, which comprises 5 parts by weight, 0.1 to 8 parts by weight of a phenolic resin and 0.1 to 10 parts by weight of an epoxy compound.