JPS5845940A - Bonding of fiber to hydrogenated nitrile rubber compound - Google Patents

Abstract

PURPOSE:To improve the bondability of fiber to hydrogenated nitrile rubber compound without using sulfur, by treating the fiber with a specific solution containing resorcinol formalin and vulcanizing the treated fiber in contact with hydrogenated nitrile rubber compound. CONSTITUTION:In bonding a fiber to a hydrogenated nitrile rubber compound, a liquid mixture of acrylonitrile/butadiene latex containing at least 3% carboxyl group and resorcinol formalin in a solid weight ratio of 10:1-2:1 (wherein the molar ratio of resorcinol to formalin is 1:3-3:1) is used in the treatment, and the treated product is vulcanized in contact with unvulcanized rubber. The fiber is immersed in advance in an isocyanate solution, epoxy solution or their mixture solution prior to the immersion in the above treating solution, and is dried, thereby enhancing the effect of treating with the above treating solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating fibers with excellent adhesive properties in composites.

In recent years, due to automobile exhaust gas regulations, the temperature around the engine has increased, so conventional rubbers such as nitrile rubber, shrimp chlorohydrin rubber, and acrylic rubber have become oil-resistant. It has become impossible to make rubber products that are also heat resistant.

However, recently it has become oil resistant. Hydrogenated nitrile rubber has emerged as a rubber that also has heat resistance and is attracting attention.

This hydrogenated nitrile rubber is a rubber that improves heat resistance, which is a drawback, without losing the oil resistance, which is an advantage of conventional nitrile rubber. In order to prevent a decrease in elasticity, hydrogen is added to the double bonds of conventional nitrile rubber in advance to prevent recombination reactions during heat aging, resulting in improved heat resistance.

Therefore, in order to maintain the heat resistance of this hydrogenated nitrile rubber, sulfur must not be used at all or as little as possible in the rubber compounding.

However, many rubber products are composites of fibers and rubber, and adhesion between fibers and rubber is important in order to satisfy the product's functionality. It is common knowledge that good adhesion can be obtained by adding sulfur to rubber.

However, heat resistance is a feature of hydrogenated nitrile rubber.

In order to provide oil resistance at the same time, it is necessary to avoid using sulfur in the formulation and to provide good adhesion to fibers.

In order to solve this problem, the inventors of the present invention made extensive research efforts and found that fibers were prepared in advance using 7-crylnitrile-butadiene latex with a ruboxyl group content of 3% or more and a resorcinol-formalin solution. lO: 1-2:
In addition, the molar ratio of resorcif to formalin in the resorcin-formalin solution is 1:3 to 3:1.
It has been found that the adhesion to the hydrogenated nide 1 full rubber compound can be improved by mixing the mixture to a ratio of up to 1, immersing it in the solution, and then heat-treating it.

In addition, if the isocyanate compound or epoxy compound solution and these are pretreated with the solution before the above treatment, and after drying, the treatment liquid of the present invention is used, better adhesive strength can be obtained. Next time.

That is, the present invention is characterized in that fibers are treated using a mixed solution having the above-mentioned composition.

Therefore, in the present invention, the fiber is cotton.

Refers to fibers commonly used for bonding with rubber, such as human silk, polyvinyl alcohol fibers, aliphatic polyamide fibers, polyester fibers, aromatic polyamide fibers, and glass fibers.

The treatment liquid is a mixture of acrylonitrile-butadiene latex having a carboxyl group content of 3% or more and resorcin formalin as described above, and the mixture has a solid content weight ratio of lo:l-2:l. It is preferable that the molar ratio of resorcinol to formalin in the resorcinol-formalin solution be in the range of 1:3 to 3:1 in order to achieve the desired effect. In particular, the latter ratio is l:l to 15:1 to obtain better adhesive strength.
It is most desirable that the blending ratio be within the range of l. After soaking and straining the fibers according to the method, heat treatment is performed.

The heat treatment temperature varies somewhat depending on the type of fiber, but it is a temperature and time sufficient to react and fix the mixed liquid attached by dipping, and is usually about 140-210°C for several minutes. In particular, when aromatic boria powder is used as a fiber, the most common temperature is 12190-200°C for about 2 minutes ◎ However, this is not necessarily restricted by the processing conditions ◎ Note that the above-mentioned processing solution It is a good idea to pre-dip the fibers in an isocyanate solution, an epoxy solution, or a mixture thereof and dry them before dipping them in the treatment solution, as this will make the subsequent treatment with the treatment solution more effective. There is, and constitutes the second invention of the present invention.

In this case, the drying temperature is preferably as low as the subsequent heat treatment temperature. For example, for aromatic polyamide fibers, the drying temperature is selected to be around 180 to 190'.

Of course, this pretreatment does not necessarily have to be carried out, but the effectiveness of the present invention as a treatment is not impaired.

Thus, after the fibers have been treated as described above, the fibers are subjected to a step of bonding with a hydrogenated nitrile rubber compound, in which case the hydrogenated nitrile rubber compound is not present. In the vulcanized state, it is brought into close contact with the fibers and vulcanization is carried out according to the usual processing conditions for rubber compounds.

The method of the present invention is particularly useful for adhering hydrogenated nitrile rubber compounds to fibers in the production of power transmission belts, conveyor belts, etc., which require oil resistance and heat resistance.

Hereinafter, specific embodiments of the method of the present invention and their effects will be described in detail using Examples.

Example 1 A hood made of aromatic polyamide X4 fiber (using DuPont's Kevlar trade name) was immersed in a treatment solution having the composition shown in Table 1, and then reacted at 200° C. for 2 minutes. The hood treated in this way is then spun onto the adhesive tape spread on the drum.
A hydrogenated nitrile rubber compound of Table 2 having a thickness of 3 cm was laminated thereon. The laminated sample was then cut by force, and vulcanized at 150°C for 30 minutes. After vulcanization, the sample was cut into 1-inch width and tested using a peel tester (Autograph manufactured by Shimabara Seisakusho). ) at a tensile speed of 50''/a. The results are shown in Table 3.

However, the molar ratio of 'Zo2 Schiff/Oya, Su, = /, *l: E1 - T'ty NBR latex *2
','SBR# *3: Nippon Synthetic Rubber VP tt *4: Denki Kagakusha OR' a Table 2 Rubber compound example 2 Hydrogenation of various codes using the processing liquid of the present invention corporation in Example 1 The adhesive strength with the nitrile rubber compound (A in Table 2) was measured in the same manner as in Example 1.

The results are shown in Table 4.

Example 3 A hood made of aromatic polyamide fibers having the composition of IX4 was immersed in a treatment solution having the composition shown in Table 5, dried at 190'C for 2 minutes, and then immersed in the A treatment solution of Example 1. It was immersed and reacted at 200'C for 2 minutes. The adhesion of the thus treated hood was then measured in the same manner as in Example 1.

The results are shown in Table 6.

11Z Sweet Proboscis Example 4 Adhesion strength was measured in the same manner as in Example 1, except that the molar ratio of resorcinol to formalin in the treatment solution A of Example 1 was changed. The results were as shown in FIG.

In this case, the latex solid content/RF solid content is/
,Met. As is clear from the figure, the range of heat to η is the best, and it can be seen that it can be practically used up to about 14 to η.

Example 5 Adhesive strength was measured in the same manner as in Example 1 by changing the solid content of resorcin/formalin to the solid content of latex with the molar ratio of resorcin and formalin in treatment solution A of Example 1 as /. The results are shown in FIG.

From the same figure, it is clear that the solid content ratio of both is \~1/
It was found that 14 to 1/1O is the most suitable and can be used practically.

Note that the ratios here are shown when the numerator and denominator are reversed.Example 6 In the A treatment solution of Example 1, acrylic to nitrile-butadiene latexes with different carboxyl group contents were used. The adhesive strength was measured in the same manner as in Example 1. The results were as shown in FIG. That is, it can be seen that a content of 3% or more is substantially good, sufficient, and practical.

As described above, according to the method of the present invention, various fibers are mixed with acrylonitrile-butadiene latex having a carboxyl group content of 3% or more and the solid content of the RFL liquid at a ratio of 1 oll N2:1, and the R/R of the RFL liquid is The molar ratio of P is l:3
Hydrogenated nitrile can be treated with a solution mixed at a ratio of ~3:1, or pretreated with an isocyanate-based solution or an epoxy-based solution, and then treated with the above-mentioned mixed solution and bonded to hydrogenated nitrile rubber. Conveyor belts and power transmission belts with excellent oil resistance, heat resistance, and adhesion made from a composite of fibers and hydrogenated nitrile rubber that can significantly improve adhesion to fibers without using sulfur in the rubber. , and other industrial products with remarkable effects.

[Brief explanation of the drawing]

Claims (1)

[Claims] / In adhesion of sl' fibers and a hydrogenated nitrile rubber compound, a mixed solution of acrylonitrile-butadiene latex containing 3% or more of carboxyl groups and resorcinol-formalin is used at lo: 1 to After treating the fibers with a solution mixed at a solid content weight ratio of 2:1 and a molar ratio of resorcin and formalin in the resorcin-formalin mixed solution at a ratio of 3 to 3:1, A method for adhering fibers and a hydrogenated nitrile rubber compound, characterized by vulcanizing the fibers in close contact with unvulcanized rubber. 2. In bonding the Im fiber and the hydrogenated nitrile rubber compound, the fiber is pretreated with an isocyanate solution, an epoxy solution, or a mixture thereof, and then treated with the mixed solution described in item 1 above, and then this is A method for bonding fibers and a hydrogenated nitrile rubber compound by vulcanizing them in close contact with unvulcanized rubber@