JPH0360853B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a method of adhering a rubber compound to fibers. Conventional technology In general, bonding between rubber and fibers has been conventionally performed using
The method used is to treat fibers with a mixture of resorcinol-formalin resin and rubber latex called RFL liquid, and then vulcanize this in close contact with unvulcanized rubber. However, in such a method, in order to achieve adhesion, it is necessary to use a rubber latex of the same type as the rubber in the rubber compound from the viewpoint of compatibility and the like. That is, the latex component to be used is limited depending on the type of rubber. Furthermore, it is also necessary that the latex used has polar groups. That is, if the latex does not have a polar group, there will be no strong interaction between the resorcinol and the formalin resin, making it impossible to achieve the desired adhesion. Therefore, when adhering ethylene-propylene copolymer rubber, hydrogenated nitrile rubber, fluorocarbon rubber, etc. that do not have polar groups, the RFL method is used because these rubbers do not have polar groups in their molecules. In this case, sufficient adhesion with the fibers cannot be achieved. Problems to be Solved by the Invention As a result of intensive research in order to solve the above-mentioned problems in adhesion between rubber compounds and fibers, the present inventors have found that a polyepoxy compound having two or more epoxy groups in the molecule has been developed. After treating the fibers, by contact vulcanization with an unvulcanized rubber compound containing a specified modified phenolic resin together with an organic peroxide,
It has been discovered that strong adhesion can be achieved between natural rubber and synthetic rubber, especially the difficult-to-adhere ethylene-propylene copolymer rubber, hydrogenated nitrile rubber, and fluorocarbon rubber mentioned above. ,
This led to the present invention. Means for Solving the Problems The present invention provides a method for bonding a rubber compound and fibers, and a method for bonding a rubber compound and fibers.
It is characterized in that it is closely vulcanized with an unvulcanized rubber compound containing a phenolic resin modified with at least one compound selected from the group consisting of cardol, anacardic acid, and cardanol. In the method of the present invention, the polyepoxy compound having two or more epoxy groups in the molecule is particularly used.
Although not limited to, preferred specific examples include, for example, ethylene glycol, glycerin,
Reaction products of polyhydric alcohols such as sorbitol and pentaerythritol, polyalkylene glycols such as polyethylene glycol, and halogen-containing epoxy compounds such as epichlorohydrin, resorcinol, bis(4-hydroxyphenyl) dimethylethane, and phenol formamide. Examples include resins, polyhydric phenols such as resorcinol/formamide resins, and reaction products of phenolic resins and halogen-containing epoxy compounds such as epichlorohydrin. In the method of the present invention, these epoxy resins are usually in solution and the fibers are treated by immersing them in the solution. After this, the fibers are heat treated. This heat treatment may be carried out at a temperature sufficient to react and fix the epoxy compound attached to the fiber, although it depends on the type of fiber used.
It is sufficient to process at 160 to 250°C for several minutes. In the method of the present invention, after drying the fibers treated with the epoxy compound, the fibers are vulcanized in close contact with an unvulcanized rubber compound containing the specified modified phenolic resin together with an organic peroxide. ,
Strong adhesion can be achieved between such rubber compounds and fibers. However, in the present invention,
The conditions for vulcanization adhesion are not particularly limited, and may be according to the usual conditions known for each rubber compound. In the method of the present invention, the fibers typically include cotton, human silk, polyvinyl alcohol fibers, aliphatic and aromatic polyamide fibers, polyester fibers, carbon fibers, glass fibers, etc., but there are no particular limitations. It includes all fibers conventionally used for bonding with rubber. Further, the rubber to which the method of the present invention can be applied may be either natural rubber or synthetic rubber as long as it can be crosslinked with organic peroxide, and is not particularly limited. In the method of the present invention, the rubbers used include natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, ethylene-propylene copolymer rubber, and chlorosulfonated polyethylene rubber. , hydrogenated nitrile rubber, urethane rubber, silicone rubber,
Examples include fluoro rubber. The above-mentioned organic peroxide is not particularly limited, and may be any conventionally known one, such as di-t-butyl peroxide, t-butyvcumyl peroxide, dicumyl Peroxide, α,α′-bis(t-butylperoxide)-p-diisopropylbenzene, 2,
5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyldi(t-butylperoxy)hexane-3,2,5-dimethyl-
2,5-di(benzoylperoxy)hexane,
t-butylperoxyisopropyl carbonate, 1,1-bis(t-butylperoxy)-3,
Examples include 5,5-trimethylcyclohexane. The amount of organic peroxide blended in the unvulcanized rubber compound is at least 0.0005 mol, preferably at least 0.001 mol, per 100 g of rubber. When the amount of organic peroxide blended into the rubber is less than 0.0005 mol per 100 g of rubber, strong adhesion between the rubber compound and the fibers cannot be obtained. However, if the amount of organic peroxide in the rubber compound is too large, the resulting vulcanized rubber may have poor practical physical properties, such as reduced elongation or excessive hardness. , in the present invention, the amount of organic peroxide in the unvulcanized rubber compound is:
Usually, 0.05 mol or less per 100 g of rubber,
Preferably, it is 0.01 mol or less. In the present invention, the modified phenol resin is used as a part of the phenol component in the production of novolak type, resol type or benzyl ether type phenol manufactured from phenols such as cresol and resorcinol in addition to phenol. and cardanol. Here, cardol, anacardic acid, and cardanol are all phenol compounds having an unsaturated long-chain alkyl group as a substituent obtained from cashew nut shell liquid. These modified phenolic resins are commercially available as so-called cashew modified phenolic resins, and such commercial products can be preferably used in the present invention. The amount of the modified phenolic resin blended in the unvulcanized rubber is usually 0.5 parts by weight or more, preferably 3 parts by weight or more per 100 parts by weight of rubber. When the amount of the modified phenolic resin is less than the above range, the rubber compound cannot be firmly bonded to the fibers by vulcanization adhesion. In the method of the present invention, the rubber compound contains, in addition to the above-mentioned components, a phenolic resin curing agent such as hexamethylenetetramine, a bismaleimide compound, and a copolymer such as an acrylic ester or methacrylic ester of a polyhydric alcohol. It may contain a crosslinking agent. Furthermore, in addition to organic peroxides, vulcanizing agents such as sulfur and triazines may be contained. Furthermore, in the case of chloroprene rubber, it may contain metal oxides. Furthermore, thiazoles,
It may contain vulcanization accelerators such as dithiocarbamates, thiurams, and thioureas. Furthermore, various reinforcing fillers, anti-aging agents, plasticizers, vulcanization aids, commonly known as rubber compounds,
It may contain an appropriate amount of processing aids and the like. Effects of the Invention As described above, according to the method of the present invention, fibers are treated with an epoxy compound having two or more epoxy groups in the molecule, and the fibers are treated with the predetermined cashew-modified phenolic resin together with an organic peroxide. By closely vulcanizing it with the unvulcanized rubber compound it contains,
Strong adhesion can be obtained between the rubber compound and the fibers. Although the method of the present invention is not limited in any way by the adhesion mechanism, it is possible to use fibers that have been given epoxy groups by treatment with an epoxy compound and an unprocessed fiber that contains the modified phenolic resin together with an organic peroxide. By closely vulcanizing the sulfur rubber compound, radicals are generated in the rubber by the organic peroxide, and the rubber molecules bond to the unsaturated modified phenolic resin through a radical reaction. At the same time, it seems that the epoxy groups in the fiber surface liquid bond with the methylol groups and phenolic hydroxyl groups of the modified phenolic resin, thus firmly adhering the rubber and fibers. EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 Each of the treatment solutions A to D shown in Table 1
A 1500D/2×3 aromatic polyamide fiber cord (Teijin Technora) was soaked and heat-treated at 210°C for 1 minute, and then adhered to a sheet of unvulcanized rubber compound 2 having the composition shown in Table 2. After heating, heat at 160℃ for 20
After vulcanization for a minute, a bond was obtained. Regarding this adhesive, the tensile speed was measured using a peel tester.
The 180° peel adhesion between the cord and the rubber was measured at 100 mm/min. The results are shown in Table 3. For comparison, the same unvulcanized rubber compound 2 as above was prepared without treatment with the epoxy compound solution.

【table】

【table】

[Table] After adhering to the sheet, vulcanize at 160℃ for 20 minutes,
Obtained adhesive. The results are also shown in Table 3.

[Table] Example 2 The same fiber cord as in Example 1 was immersed in epoxy compound solution A shown in Table 1 and heat treated at 210°C for 1 minute, and then an unvulcanized rubber compound having the composition shown in Table 2 was prepared. After adhering to sheets 1 to 6, heat at 160℃ for 20 minutes.
After vulcanization for a minute, a bond was obtained. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 4.

[Table] From the results shown in Table 4, it is understood that only the rubber compound containing an organic peroxide and a predetermined modified phenolic resin can be firmly adhered to the fiber cord. Example 3 The same fiber cord as in Example 1 was immersed in epoxy compound solution A shown in Table 1 and heat treated at 210° C. for 1 minute. Separately, the same fiber cord as in Example 1 was immersed in epoxy compound solution A shown in Table 1,
After heat treatment at 210°C for 1 minute, immersed in each of RFL liquids E to G having the composition shown in Table 5,
It was heat-treated at ℃ for 1 minute to fix it on the fiber cord.

【table】 Each fiber cord treated in this way was

【table】

[Table] After being brought into close contact with a sheet of unvulcanized rubber compound 2 having the composition shown in Table 2 and a sheet of unvulcanized rubber compound 7 to 9 having the composition shown in Table 6, the mixture was heated at 160°C for 20
After vulcanization for a minute, a bond was obtained. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 7.

[Table] From the results shown in Table 7, the fiber cords treated with treatment liquid A were strongly bonded to all rubber compounds, but the fiber cords treated with treatment liquids E, F, or G were partially bonded. Strong adhesion was achieved only with the rubber compound. Example 4 Each of the treatment liquids A or B shown in Table 1
1100D/2×5 polyester fiber cord (Teijin
Co., Ltd.) and heat treated at 210℃ for 1 minute.
After being brought into close contact with a sheet of unvulcanized rubber compound 2 having the composition shown in Table 2, it was vulcanized at 160°C for 20 minutes,
Obtained adhesive. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 8. of the present invention

[Table] According to the method, polyester fiber cords were also able to be firmly adhered to the rubber compound.

Claims (1)

[Claims] 1. In the method of adhering a rubber compound to fibers, after treating the fibers with an epoxy compound having two or more epoxy groups in the molecule, at least an organic peroxide and at least one selected from the group consisting of cardol, anacardic acid, and cardanol are added. A method for adhering a rubber compound and fibers, the method comprising closely vulcanizing an unvulcanized rubber compound containing a phenolic resin modified with one type of compound.