JPS6024131B2 - Method of adhering fibers and hydrogenated nitrile rubber compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating fibers with excellent adhesion in composites of fibers and hydrogenated nitrile rubber compounds.

In recent years, due to automobile exhaust gas regulations, the temperature around the engine has increased, so it has become impossible to make rubber products that are oil resistant and heat resistant at the same time using conventional rubber examples such as nitrile rubber, shrimp chlorohydrin rubber, and acrylic rubber. Ta.

However, recently, hydrogenated nitrile rubber has emerged as a rubber that has oil resistance and heat resistance at the same time, and is attracting attention.

This hydrogenated nitrile rubber is a rubber that improves oil resistance, which is a disadvantage, without losing the oil resistance, which is an advantage of conventional nitrile rubber, and reduces the decrease in rubber elasticity due to the recombination reaction of sulfur during heat aging. In order to prevent this, hydrogen is added to the double bonds of conventional nitrile rubber in advance to make it difficult for recombination reactions to occur 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, in order to simultaneously provide the heat resistance and oil resistance that are the characteristics of hydrogenated nitrile rubber, it is necessary to improve adhesion to fibers without using sulfur in the compound. Therefore, in order to solve this problem, the present inventors conducted intensive research and found that
The fibers are made of acrylonitrile-butadiene latex with a carboxyl group content of 3% or more, and then mixed with a solcin-formalin solution at a solid weight ratio of 10:1 to 2:1. By soaking in a mixed solution with a molar ratio of 1:3 to 3:1, and then heat-treating,
It has been discovered that the bush adhesion to hydrogenated nitrile rubber compounds can be improved.

Furthermore, it has been found that better adhesive strength can be obtained by pre-treating with a solution of an isocyanate compound or an epoxy compound or a mixed solution of these before the above-mentioned treatment, and using the treatment liquid of the present invention after drying. That is, the present invention is characterized in that fibers are treated using a mixed solution having the above-mentioned formulation. Here, in the present invention, fibers include fibers commonly used for bonding with rubber, such as wire, silk, polyvinyl alcohol fiber, aliphatic polyamide fiber, polyester fiber, aromatic polyamide fiber, and glass fiber. say.

The treatment liquid is a mixture of acrylonitrile-butadiene latex having a carboxyl group content of 3% or more and resorcinol-formalin, as described above, and the solid content of the mixture is 10:1 to 2:1 by weight. 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 1
:1 to 1.5:1 is most desirable. The mixing ratios of each of these will be sequentially clarified in the examples described later. As a method for treating fibers with such a mixture, the fibers are usually crushed according to the soaking method, and then heat treated. The heat treatment temperature varies somewhat depending on the type of fiber, but it is sufficient temperature and time to react and fix the mixed liquid attached by dipping, and is usually carried out at about 140 to 210 qo for several minutes.

Especially when using aromatic polyamide as fiber, 1
The most common is about 90 to 200 q○ for about 2 minutes. However, it is not necessarily restricted by the processing conditions. 0 It should be noted that prior to immersion in the treatment liquid, the fibers are immersed in an isocyanate solution, an epoxy solution, or a mixture thereof, and then dried, in order to make the treatment with the treatment liquid more effective. The second aspect of the present invention is very good.
constitutes an invention.

The drying temperature in this case is preferably as low as the subsequent heat treatment temperature, and for example, for aromatic polyamide fibers, a temperature of about 180 to 190 oo is selected.

Of course, even if this treatment is not necessarily carried out, the effectiveness of the treatment of the present invention is not impaired.

Thus, after the fibers have been treated as described above, they are subjected to a step of bonding them with a hydrogenated nitrile rubber compound, in which case the hydrogenated nitrile rubber compound is bonded to the above-mentioned compound in an unvulcanized state. The fibers are brought into close contact and vulcanization is carried out according to the usual processing conditions for rubber compounds.

The method of the present invention is particularly useful for bonding a hydrogenated nitrile rubber compound to fibers in the production of power transmission belts, compare 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 cord of aromatic polyamide fiber having a cylindrical structure (used under the trade name Kepler, manufactured by DuPont) was immersed in a treatment solution having the composition shown in Table 1, and then reacted at 200°C for 2 minutes.

The thus treated cord was then spun onto an adhesive tape spread on a drum, and a hydrogenated nitrile rubber compound of Table 2 having a thickness of 3 ribs was laminated thereon. The thus laminated sample was then cut and 15,000
After vulcanization, the sample was cut into 1-inch pieces and tested using a peel tester (using Shimadzu's Autograph).
The adhesive strength was measured at a tensile speed of 5 m/min.
The results are shown in Table 3. Table 1 However, molar ratio of resorcin/formalin = 1.2/1 *1: Nippon Zeon Co., Ltd. NBR latex *2: 〃 SBR 〃 *3: Japan Synthetic Rubber VR 〃 *4: Denki Kagaku Co., Ltd. CR 〃 Table 2 Rubber Compound Table 3 Example 2 Using the treatment liquid of the present invention method A of Example 1, various cords were attached, and the adhesion strength with the hydrogenated nitrile rubber compound (A in Table 2) was determined as in Example 1. Measurements were made in the same manner.

The results are shown in Table 4. Table 4 Example 3 After soaking a cord of aromatic polyamide fiber having the composition shown in Table 5 in the treatment solution having the composition shown in Table 5, it was dried at 19,000 for 2 minutes, and then treated with the A treatment solution of Example 1. Soaked in
20,000 for 2 minutes.

The adhesive strength of the thus treated cord was then measured in the same manner as in Example 1. The results are shown in Table 6. Table 5
(Weight) *5: Isocyanate compound manufactured by Kasei Upjohn Co., Ltd. Table 6 Example 4 The adhesive strength was measured in the same manner as in Example 1 by changing the molar ratio of resorcinol to formalin in the treatment solution A of Example 1.

The results were as shown in FIG. In this case, the latex solid content/RF was 4/1.

As is clear from the figure, the range of 1/1 to 2/1 is the best, and it can be seen that it is practically usable up to about 1/3 to 3/1. Example 5 Adhesive strength was measured in the same manner as in Example 1, with the molar ratio of resorcin and formalin being 1.2/1 in treatment A of Example 1, and the solid content of resorcin/formalin versus the solid content of latex being varied.

The results are shown in FIG. As is clear from the figure, the most suitable solid content ratio for both is 1/4 to 1/8, and 1/4 to 1/8.
It was found that a ratio of 2 to 1/10 is sufficient for practical use.

Note that the percentages shown here are shown with the numerator and denominator reversed. Example 6 Adhesion strength was measured in the same manner as in Example 1 using acrylonitrile-butadiene latexes having different carboxyl group contents in the treatment solution A of Example 1.

The result was the obstruction shown in Figure 3.

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 a mixture of carboxyl group-containing 3% G Kugami acrylonitrile-butadiene latex and RFL liquid in a solid content of 10:1 to 2:1. And, the RFL liquid is treated with a mixed solution with an R/F molar ratio of 1:3 to 3:1, or it is pretreated with an isocyanate solution or an epoxy solution and then treated with the mixed solution. By adhering to hydrogenated nitrile rubber, the adhesive strength with fibers can be significantly improved without using sulfur in hydrogenated nitrile rubber. It has remarkable effects when applied to conveyor belts, power transmission belts, and other industrial products with excellent heat resistance and adhesive properties.

Brief Explanation of the Drawings Figure 1 is a chart showing the correspondence between the molar ratio of resorcin and formalin in the mixed treatment solution and the adhesive strength in the method of the present invention, and Figure 2 shows the relationship between the solid content of resorcin and formalin in the same treatment solution. FIG. 3 is a chart showing the relationship between the ratio of latex solid content and adhesive strength, and FIG. 3 is a chart showing the relationship between carpoxyl group content and adhesive strength.

Multi-7 diagrams Multi-Z diagram hair drawing

Claims (1)

[Claims] 1. For adhesion of fibers and hydrogenated nitrile rubber compound, a mixture of acrylonitrile-butadiene latex with a carboxyl group content of 3% and resorcinol-formalin is mixed in a ratio of 10:1 to 2:1. The fibers are treated with a solution prepared by mixing the resorcinol and formalin in a resorcinol-formalin mixed solution with a solid content weight ratio of 1:3 to 3:1, and then this is A method for adhering fibers and a hydrogenated nitrile rubber compound, characterized by vulcanization in close contact with vulcanized rubber. 2. In bonding fibers and hydrogenated nitrile rubber compounds, after pre-treating the fibers with an isocyanate solution, an epoxy solution, or a mixture thereof,
The above acrylonitrile-butadiene latex and resorcinol-formalin mixture are mixed at a solid content weight ratio of 10:1 to 2:1, and the molar ratio of resorcinol to formalin in the resorcinol-formalin mixed liquid is from 1:3 to 2:1. A method for adhering fibers and a hydrogenated nitrile rubber compound, characterized by treating with a solution mixed at a ratio of 3:1, and then vulcanizing this in close contact with unvulcanized rubber.