JPH046734B2 - - 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 latex called RFL liquid, and then vulcanize this in close contact with unvulcanized rubber. However, in such a method, it is necessary to change the latex components depending on the type of rubber from the viewpoint of compatibility and the like. Furthermore, when adhering ethylene-propylene copolymer rubber, hydrogenated nitrile rubber, fluorocarbon rubber, silicone rubber, etc., these rubbers do not have unsaturated bonds in their molecules or contain functional groups that are effective for adhesion. Due to the lack of adhesiveness, the RFL method cannot achieve sufficient adhesion with the fibers. 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 discovered that polyisocyanate compounds having two or more isocyanate groups in the molecule have been developed. The fibers are treated with a silane coupling agent having a carbon-carbon unsaturated bond such as a methacrylic group in the molecule and a silane coupling agent having an amino group in the molecule, and then treated with an organic peroxide. Natural rubber and synthetic rubber, especially the above-mentioned difficult-to-adhesive ethylene-propylene copolymer rubber, hydrogenated nitrile rubber, and fluoro rubber, can be cured by contact vulcanization with an unvulcanized rubber compound containing , silicone rubber, etc., have also been found to be able to achieve strong adhesion with fibers, leading to the present invention. Means for Solving the Problems The present invention provides a method for adhering a rubber compound to fibers, in which the fibers are treated with a polyisocyanate compound having two or more isocyanate groups in the molecule, and then the fibers are treated with a polyisocyanate compound having the general formula YSiX ₃ ( In the formula, Y represents an organic functional group having a vinyl group, a methacrylic group, or an allyl group, and X represents a halogen,
It represents an alkoxy group or an acyl group, and X's may be the same or different. ) and a silane coupling agent represented by the general formula ZSiX ₃ (wherein, Z represents an organic or inorganic functional group having an amino group, X represents a halogen, an alkoxy group, or an acyl group, and the Xs may be the same, It is characterized in that it is treated with a silane coupling agent represented by (which may be different) and then is closely vulcanized with an unvulcanized rubber compound containing an organic peroxide. In the method of the present invention, the polyisocyanate compound having two or more isocyanate groups in the molecule is not particularly limited, but preferred specific examples include tolylene diisocyanate, m-phenylene diisocyanate, etc. , diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane diisocyanate and the like. Furthermore, molecular chains obtained by reacting these polyisocyanates with a compound having two or more active hydrogens in the molecule, such as trimethylolpropane or pentaerythritol, under conditions where the isocyanate group/hydroxyl group molar ratio is greater than 1. A urethane prepolymer whose terminal end is an isocyanate group, or the polyisocyanate, for example, a phenol,
Phenols such as thiophenol, cresol and resorcinol, tertiary alcohols such as t-butanol and t-pentanol, diphenylamine,
With aromatic secondary amines such as xylidine, imides such as phthalic acid imide, lactams such as caprolactam and valerolactam, oximes such as acetoxime, methyl ethyl ketoxime, and cyclohexanone oxime, or so-called blocking agents such as sodium nitrite. Examples include blocked polyisocyanates. In the method of the present invention, these polyisocyanate compounds are usually made into a solution, and the fibers are treated by immersing them in such a solution. After this, the fibers are heat treated. This heat treatment may be carried out at a temperature sufficient to react and fix the polyisocyanate compound attached to the fibers, although it depends on the type of fiber used, and is usually carried out at 160 to 250° C. for several minutes. Fibers treated with polyisocyanate compounds are
Then, the general formula YSiX ₃ () (wherein, Y represents an organic functional group having a vinyl group, a methacrylic group, or an allyl group, and X represents a halogen,
It represents an alkoxy group or an acyl group, and X's may be the same or different. ) and the general formula ZSiX ₃ () (wherein, Z represents an organic or inorganic functional group having an amino group, X represents a halogen, an alkoxy group, or an acyl group, and the Xs are the same as each other) (However, they may be different.) Treat with a silane coupling agent represented by: Here, in the method of the present invention, the fibers may be treated with a mixture of the above-mentioned silane coupling agents at the same time, or the fibers may be treated with each silane coupling agent in stages, although the order does not matter. . As the silane coupling agent represented by the general formula (), those in which Y is an organic functional group having a vinyl group, methacrylic group, or allyl group, and in which X is chlorine are particularly preferably used. Specific examples of such silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane,
vinyltris(β-methoxyethoxy)silane,
Examples include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltris(β-methoxy)silane, and vinyltriacetoxysilane. As the silane coupling agent represented by the above general formula (), those in which X is chlorine are particularly preferably used. Specific examples of such silane coupling agents include γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, and bis(β-hydroxyethyl)γ-aminopropyltrimethoxysilane. Ethoxysilane, N-(trimethoxysilylpropyl)diethylenetriamine, N-(trimethoxysilylpropyl)urea, carboethoxyethylaminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane, aminophenyltrimethoxysilane, N-( dimethoxymethylsilylpropyl) ethylenediamine, and the like. In the method of the present invention, when a mixture of these silane coupling agents is used, the mixing ratio of each of them is in the range of 10 to 90 mol%, but preferably in the range of 30 to 70 mol%. , particularly preferably in approximately equimolar ratios. However, when the treatment is carried out in stages, the amount of adhesion to the fibers does not need to be within the above range. These silane coupling agents, either as a mixture or alone, are usually provided in solutions using water and alcohol as solvents and are treated by immersing the fibers in such solutions. In the method of the present invention, after drying the fibers treated with a silane coupling agent, the rubber compound and the fibers are closely vulcanized with an unvulcanized rubber compound containing an organic peroxide. Strong adhesion can be achieved between. However, in the present invention, the conditions for vulcanization adhesion are not particularly limited, and may be any conventional 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 organic peroxide, such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, Oxide, α,α′-bis(t-butylperoxy)-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 method of the present invention, the rubber compound may contain vulcanizing agents such as sulfur and triazines in addition to the above-mentioned organic peroxides. Furthermore, in the case of chloroprene rubber, it may contain metal oxides. Furthermore, vulcanization accelerators such as thiazoles, dithiocarbamates, thiurams, and thioureas may be contained. Furthermore, it may contain appropriate amounts of various reinforcing fillers, anti-aging agents, plasticizers, vulcanization aids, processing aids, etc. that are commonly known as rubber compounds. The rubber compound may also contain ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, bismaleimide, etc. as co-crosslinking agents. Effects of the Invention As described above, according to the method of the present invention, fibers are treated with a polyisocyanate compound having two or more isocyanate groups in the molecule, and then treated with a mixture of a predetermined silane coupling agent. rear,
By closely vulcanizing this with an unvulcanized rubber compound containing an organic peroxide, strong adhesion can be obtained between the rubber compound and the fibers. In the method of the present invention, although not limited by the adhesion mechanism, the fibers are modified and activated by treatment with a polyisocyanate compound, so that the fibers have amino groups. The silane coupling agent reacts to fix silanol groups on the fiber, and the silanol group of the silane coupling agent, which has a carbon-carbon unsaturated bond, undergoes a condensation reaction and finally forms on the fiber. It appears that the unsaturated bonds are fixed.
After this, in vulcanization adhesion, radicals are generated in the rubber molecules by the organic peroxide, and at the same time, the rubber molecules are crosslinked with each other, and at the same time, the unsaturated bonds in the silane coupling agent and the radicals in the rubber are It appears that the reaction causes a strong bond between the rubber and the 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 Isocyanate compound solutions A to C shown in Table 1
A 1500D/2×3 aromatic polyamide fiber cord (Technora manufactured by Teijin Ltd.) was immersed in each of the
After heat treatment at 210℃ for 1 minute, it was immersed in silane coupling agent solution d shown in Table 2, and heated at 100℃ for 1 minute.
It was heated for a minute to fix it to the fiber cord.

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[Table] The fiber cord treated in this manner was brought into close contact with a sheet of unvulcanized rubber compound 1 having the composition shown in Table 3, and then vulcanized at 160° C. for 20 minutes to obtain an adhesive. Regarding this adhesive, the tensile speed was measured using a peel tester.
Adhesive force was measured at 100 mm/min. The results are shown in Table 4.

[Table] For comparison, Table 4 also shows the results obtained when the samples were treated only with the silane coupling agent d without being treated with the polyisocyanate compound solution. It is shown that even if the fiber cord is treated only with a silane coupling agent, it is not possible to obtain good adhesion with the rubber. Example 2 The same fiber cord as in Example 1 was immersed in isocyanate compound solution A shown in Table 1 and heat treated at 210°C for 1 minute, then immersed in silane coupling agent solution d shown in Table 2 and heated at 100°C. Heat for 1 minute with
Fixed to fiber cord. In addition, the same fiber cord as in Example 1 was similarly immersed in polyisocyanate compound solution A, and after heat-treated at 210°C for 1 minute, it had the composition shown in Table 5.
It was immersed in RFL liquids g to i and heated at 230°C for 1 minute to fix it on the fiber cord. The fiber cords treated in this manner were converted into unvulcanized rubber compounds 1 to 11 having the compositions shown in Table 3 and unvulcanized rubber compounds 12 to 15 having the compositions shown in Table 6 above.
After adhering to the sheet, it was vulcanized at 160°C for 20 minutes to obtain an adhesive. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 7. Fiber cords treated with polyisocyanate compound solutions produced strong adhesion with all rubber formulations containing organic peroxides, whereas fiber cords treated with RFL liquid produced strong adhesion with only some rubber formulations. Good results were obtained.

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[Table] Example 3 The same fiber cord as in Example 1 was immersed in polyisocyanate compound solution A shown in Table 1, heat treated at 210°C for 1 minute, and then silane coupling agent solutions a to f shown in Table 2 were added. and heated at 100°C for 1 minute to fix it on the fiber cord. The thus treated fiber cord was brought into close contact with a sheet of unvulcanized rubber compound 1 having the composition shown in Table 3, and then vulcanized at 160° C. for 20 minutes to obtain an adhesive. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 8. It has been shown that strong adhesion can be obtained by treating fiber cords with silane coupling agents having carbon-carbon unsaturated bonds and silane coupling agents having amino groups. Example 4 The same fiber cord as in Example 1 was immersed in polyisocyanate compound solution A shown in Table 1, heat treated at 210°C for 1 minute, and then treated with treatment solutions j to l shown in Table 9.
and heated at 100°C for 1 minute to fix it on the fiber cord.

[Table] The fiber cord treated in this manner was brought into close contact with a sheet of unvulcanized rubber compound 1 having the composition shown in Table 3, and then vulcanized at 160° C. for 20 minutes to obtain an adhesive. The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 10.

[Table] By treating the fiber cord with a silane coupling agent mixture in which the silane coupling agent having carbon-carbon unsaturated bonds and the silane coupling agent having amino groups are in an equimolar ratio, a strong It is shown that adhesion is obtained.

Claims (1)

[Claims] 1. In a method of adhering a rubber compound to fibers, the fibers are treated with a polyisocyanate compound having two or more isocyanate groups in the molecule, and then the general formula YSiX ₃ (wherein Y is Represents an organic functional group having a vinyl group, methacrylic group or allyl group, X is a halogen,
It represents an alkoxy group or an acyl group, and X's may be the same or different. ) and a silane coupling agent represented by the general formula ZSiX ₃ (wherein, Z represents an organic or inorganic functional group having an amino group, X represents a halogen, an alkoxy group, or an acyl group, and the Xs may be the same, ) A rubber compound characterized in that it is treated with a silane coupling agent represented by (2) and then intimately vulcanized with an unvulcanized rubber compound containing an organic peroxide. How to bond with fibers.