JPH036933B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesion method for improving the aged adhesion between organic fibers such as nylon, polyester, and vinylon and peroxide vulcanized rubber compounds. Conventionally, resorcinol was used to bond fibers and rubber compounds as reinforcing materials for tires, conveyor belts, etc.
Formaldehyde precondensates are commonly used. However, it is known that rubber reinforcing fibers treated with resorcinol-formaldehyde latex (RFL) rapidly lose their adhesive strength over time if left in high temperatures. This decrease in adhesive strength due to aging is due to the deterioration of the RFL adhesive, which is caused by oxygen and ozone in the atmosphere and migration of peroxide in the rubber compound (in the case of peroxide vulcanization). The deterioration is further accelerated by heat. The cause of this deterioration is that the carbon-carbon double bonds in the rubber latex are destroyed by oxygen or ozone absorbed into the rubber latex, and the affinity with the adhered rubber and physical interdiffusion are lost. It is thought that the adhesive strength decreases. By the way, in order to solve this problem, a method has recently been proposed in which a rubber anti-aging agent is added to the RFL adhesive made of a resorcinol-formaldehyde initial condensate and rubber latex (see Japanese Patent Publication No. 18493/1983). This method is not very effective for aging-resistant adhesion between peroxide-vulcanized rubber compounds and fibers because the rubber anti-aging agent reacts with the rubber latex during drying baking of the fibers dipped in the adhesive. It was also found that RFL containing a rubber anti-aging agent had problems with thermal stability, such as failure to gel. The present invention is based on the above knowledge, and the present invention is based on the above knowledge.
The task was to improve the problems of RFL adhesion,
As a result of various research, we have arrived at this.
The objective is to streamline the process without adding rubber anti-aging agents to RFL adhesives. That is, in the present invention, organic fibers treated with an RFL adhesive solution are then immersed in an aqueous solution, emulsion, or suspension of an antiaging agent for rubber, dried, and then processed into a peroxide vulcanized rubber compound. It is characterized by being adhered to. In the present invention, the fibers treated with the RFL adhesive solution are organic fibers such as nylon, polyester, and vinylon, and include various organic fibers that are bonded to rubber compounds. Further, the rubber anti-aging agent used in the present invention may be any conventionally used anti-aging agent for rubber. For example, as an imidazole-based anti-aging agent, 2-mercapto benzimidazole may be used. , Zn-2-mercapto benzimidazole, 2-mercapto methylbenzimidazole, 1,3-bisdimethylaminopropyl 2-thiourea, and the like. Then, the organic fibers are treated with the anti-aging agent in an aqueous solution, emulsion or suspension. In this case, the concentration of the anti-aging agent can be used as long as it is in the range of 1 to 50%, but the preferred concentration is 2 to 20%, and if it is less than 2%, the effect will be weak.
Furthermore, when the amount exceeds 20%, the initial adhesive strength tends to gradually decrease. After organic fibers, that is, RFL-treated organic fibers, are immersed in the anti-aging agent for rubber, they are dried at 100° C. for about 4 minutes and bonded to the rubber compound. Here, the rubber compound is a peroxide vulcanized rubber compound, and includes one or a blend of various rubbers such as natural rubber, isoprene rubber, ethylene propylene rubber, and chloroprene rubber. When bonded in this way, there is almost no change in the initial peeling force between the fiber and the rubber compound over time at high temperatures, and excellent aging-resistant adhesion performance is achieved. This method is significantly different from the method in which anti-aging agents are added. Hereinafter, the method of the present invention will be explained in more detail by further showing examples. Example 1 A 6,6 nylon canvas having a composition of 1260D/1 x 1260D/1/65 x 65/5 cm was made of a composition shown in Table 1 below.
The sheets were immersed in RFL solution and baked at 200°C for 2 minutes, then immersed in an aqueous solution of each rubber anti-aging agent listed in Table 2 and dried at 100°C for 4 minutes, forming sheets of the rubber compounds listed in Table 3. Along with laminating and vulcanizing,
After vulcanization, peel strength and aged adhesive strength were measured. In addition, the aged adhesive strength of the sample after vulcanization is 150
The peel strength was measured after being left in a gear oven at ℃ for 7 days. The results of each measurement above are shown in the second
It was as listed in the table. Table 1 (weight ratio) Resorcinol 11 Formalin (37%) 22.8 Caustic soda 1 JSR#0652 22.0 JSR#2108SS 4.3 Water 40 total 100.8

【table】

[Table] Table 3 (Weight) EPR: 100 ZnO: 5 Stearic acid: 1 Anti-aging agent: 5 Carbon black: 60 Acrylic acid ester: 1.5 Dicumyl peroxide (40% concentration)
: 10 Example 2 The adhesive described in Example 1 was prepared by immersing an aqueous solution of 1,3-bisdimethylaminopropyl-2-thiourea in an adhesive solution prepared by adding 4 PHR to the RFL solution shown in Table 1 above, and baking at 200°C for 2 minutes. Canvas (A) and Table 1
Example 1 and canvas (B) were immersed in RFL liquid and baked at 200°C for 2 minutes, then immersed in a 4% aqueous solution of 1,3 bisdimethylaminopropyl dithiourea, and dried at 100°C for 4 minutes. When the peel strength was measured in the same manner, the results were as shown in Table 4.

[Table] As is clear from the results in Tables 2 and 4 above, the method of the present invention, which involves adhesion treatment with RFL liquid and then immersion in an aqueous emulsion or suspension of an anti-aging agent, is superior to the conventional method. It is confirmed that there is almost no change in the initial peeling force between the fiber and rubber over time at high temperatures, and that it has excellent aging-resistant adhesion.

Claims (1)

[Claims] 1. Organic fibers are treated with a fiber treatment adhesive consisting of a resorcinol-formaldehyde initial condensate and rubber latex, and then treated with an aqueous solution, emulsion, or suspension of an antiaging agent for rubber, and then treated with peroxide. A method for adhering fibers and rubber compounds, characterized by adhering to a vulcanized rubber compound. 2. The anti-aging agent is an anti-aging agent selected from the group of 2-mercapto benzimidazole, Zn-2-mercapto benzimidazole, 2-mercapto methylbenzimidazole, and 1,3-bisdimethylaminopropyl 2-thiourea. A method of adhering a fiber and a rubber compound according to claim 1.