JPH0362731B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a composite material consisting of rubber and a metal material, which is particularly used in rubber industrial products such as vehicle tires and conveyor belts, and which exhibits adhesive properties between rubber and metal after aging. The invention relates to composite materials with excellent properties. (Prior Art) In recent years, the performance required of vehicle tires, conveyor belts, etc. has widened. Particularly in vehicle tires, radial tires have become the mainstream product, from passenger car tires to large tires for trucks and buses, and together with the development of tread rubber compounding technology, the lifespan of tires has significantly improved. Further, after the first life of large tires for trucks and buses has ended, the tires are used for a second or even a third time by renovating the tread portion. Therefore, the belt and carcass of a vehicle tire must withstand use for hundreds of thousands of kilometers. The above radial tires are characterized by their handling stability,
In order to improve structural durability, abrasion resistance, and puncture resistance, a steel cord material with a rubber layer coated on the belt or carcass is used. In such tires, adhesion between rubber and metal becomes a problem. Normally, rubber and metal materials are bonded together by the reaction between the sulfur mixed in the rubber during vulcanization and the copper in the plating of the metal material, forming sulfide at the interface between the rubber and metal materials. There is. When this adhesion is broken due to heat generation due to hysteresis loss of the rubber material while the tire is running, the steel cord and its covering rubber layer separate, causing so-called separation, making the tire unable to run. Additionally, the tread or sidewall of the tire may be damaged during driving. If this damage reaches the steel cord material, the water that has entered through the damage vaporizes due to heat generated during running and enters between the filaments of the steel cord, destroying the adhesion between the steel cord and its covering rubber, and causing the separation. Trigger Shion. Furthermore, if the air filled in the tire contains moisture, the moisture may enter from inside the tire, where the rubber is thin, and reach the steel cord, causing the same separation as described above. In order to prevent such a phenomenon, various techniques have been disclosed to improve the adhesion between rubber and steel cord. One of these is the technology of compounding the rubber that coats the steel cord. It was discovered in the 1950s that adding an organic acid cobalt salt to rubber improves the adhesion.
Many studies have been conducted on the amount and types of it. For example, JP-A-60-42440 discloses improving adhesion by optimizing the respective amounts of sulfur and organic acid cobalt salt. Furthermore, an HRH composition containing white carbon, resorcinol, and hexamethylenetetraamine has been proposed. However, adding a large amount of organic acid cobalt salt causes deterioration of unvulcanized rubber and decreases adhesive strength due to high-temperature vulcanization, long-term vulcanization, or heat aging after running, and HRH-based rubber compositions are susceptible to environmental pollution, There are problems during production such as rubber burning. Additionally, there are techniques for improving the plating of metal materials. Japanese Patent Publication No. 51-8389 and Japanese Patent Publication No. 55-105548 disclose plating layers containing nickel,
Furthermore, alloy plating containing three or four types of metals is disclosed in Japanese Patent Application Laid-Open No. 55-45884 and Japanese Patent Application Laid-open No. 55-71887.
Publication No. 105548, Japanese Patent Publication No. 55-105548, Japanese Patent Publication No. 1987-10554-
Publication No. 826045, Japanese Patent Application Publication No. 1989-89940, Publication No. 89940, Japanese Patent Publication No.
It is disclosed in JP-A No. 61-243194 and Japanese Patent Application Laid-Open No. 61-72545. (Problems to be Solved by the Invention) The present invention solves problems such as adhesion after heat aging and adhesion after wet heat aging (hereinafter referred to as "heat resistance" and "moist heat resistance"), especially when dealing with other problems during production. The purpose is to provide a composite material consisting of a rubber-treaded metal material that is further improved than the conventional one without causing problems, and has a metal material with an improved tacky layer and a compounding content suitable for the metal material. This objective is achieved by combining it with rubber. (Means for Solving the Problems) The present invention provides 100 parts by weight of rubber with 0.5 parts by weight or less of an organic acid cobalt salt, 3 to 6 parts by weight of sulfur, and N-oxydiethylene-2-benzothia as a vulcanization accelerator. A composite material consisting of a rubber composition containing zolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide and a metal material plated with a ternary alloy consisting of copper, zinc, and nickel. be. Here, as the organic acid cobalt salt, cobalt naphthenate, cobalt oleate, cobalt maleate, cobalt stearate, etc. are applied, but in particular, those with a cobalt content of 8 to 10% are effective in terms of initial adhesion. preferable. In addition, the shape of the metal material can be freely selected depending on the industrial product to which the composite material is applied, but when applying the composite material of the present invention to the above-mentioned conveyor belt or vehicle tire, the shape of the metal material is , especially used as steel cord. (Function) It has been conventionally believed that initial adhesion is poor unless the amount of organic acid cobalt salt exceeds 0.5 parts by weight per 100 parts by weight of rubber. However, the present invention uses N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2 as a vulcanization accelerator.
-add benzothiazolylsulfenamide;
In addition, when the organic acid cobalt salt content is 0.5 parts by weight or less, by combining it with a metal material plated with a ternary alloy consisting of copper, zinc, and nickel.
Even when the organic acid cobalt salt content is 0, that is, no organic acid cobalt salt is contained, sufficient adhesive strength is generated. Therefore, problems during production and aging after vulcanization caused by a large amount of organic acid cobalt salt can be prevented. Here, when the sulfur content of the rubber composition according to the present invention is less than 3 parts by weight, sufficient initial adhesive strength cannot be obtained, and when it exceeds 6 parts by weight, the heat resistance is reduced. Further, the amount of the vulcanization accelerator is preferably in the range of 0.5 to 2 parts by weight. If it is less than 0.5 parts by weight, vulcanization tends to be slow and adhesion may deteriorate. Further, if the amount is more than 2 parts by weight, the modulus of the rubber becomes too high, which may adversely affect adhesion and the breaking strength of the rubber itself. Next, the plating of the metal material used in the present invention requires ternary alloy plating consisting of copper, zinc, and nickel. The composition of this plating is copper
A plating alloy containing 60 to 75% by weight of nickel, 4 to 10% by weight of nickel, and the balance zinc is preferably used. If the copper content is less than 60% by weight, the initial adhesive strength will be poor, and if it exceeds 75% by weight, the nickel/zinc content will be low and the heat resistance and moist heat resistance will be insufficient. A large amount of nickel is not required; 4% by weight or more is sufficient, but if it exceeds 10% by weight, the adhesive reaction will be inhibited and it will be difficult to obtain the necessary initial adhesive strength. (Example) Rubbers were prepared with the basic rubber formulation shown in Table 1, varying the sulfur and cobalt stearate, and changing and varying the vulcanization accelerator based on Table 2.

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[Table] In Table 2, rubber formulations 1 to 18 are rubber formulations according to the present invention. Next, 1×5/0.25 steel cords were plated with the compositions shown in Table 3.

[Table] Several types of rubber compositions shown in Table 2 and steel cords shown in Table 3 are combined and vulcanized under certain conditions. After aging under the conditions shown in Table 4, the rubber is separated from the cord by machine. The peeling force when the cord was peeled off was measured, and the state of rubber attachment on the cord surface was visually evaluated using a 10-point scale. The result is the fifth
They are shown in Tables (1) and (2) and Table 6 (1) and (2). A larger number represents a better result.

[Table] Condition (a) is the initial adhesion strength measurement condition, condition (b) and (c)
indicates the heat and humidity resistance, and condition (d) indicates the measurement conditions for the heat resistance.

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[Table] Rubber compound 1 from Table 5 (1) (2) and Table 6 (1) (2)
-18 and steel cords B to H are the composite materials according to the invention. Table 5 (1) and (2) show the visually observed peeling state using a 10-point scale, with larger numbers indicating better results. Table 6 (1) and (2) show the measurement results of the peeling force. The composite material according to the invention showed good results under all conditions. Furthermore, rubber formulations 1 to 3, 7
In Examples 9 and 13 to 18, it became possible to obtain a composite material with good adhesiveness without using an organic acid cobalt salt. This effect is especially true for steel cord C~
It is noticeable when combined with F. (Effects of the invention) The present invention improves the adhesion between rubber and metal materials at the initial stage, after heat aging, and after moist heat aging,
Furthermore, it has become possible to solve various problems that occur during production, such as environmental pollution and rubber burning.

Claims (1)

[Claims] 1. 0.5 organic acid cobalt salt per 100 parts by weight of rubber.
3 to 6 parts by weight of sulfur and N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2- as a vulcanization accelerator.
A composite material consisting of a rubber composition containing benzothiazolylsulfenamide and a metal material plated with a ternary alloy of copper, zinc, and nickel. 2. The composite material according to claim 1, wherein the composition of the ternary alloy plating is 60 to 75% by weight of copper, 4 to 10% by weight of nickel, and the remainder zinc. 3. The composite material according to claim 1, wherein the vulcanization accelerator is 0.5 parts by weight or more and 2 parts by weight or less. 4 The cobalt content of the organic acid cobalt salt is 8
Composite material according to any one of claims 1 to 3, characterized in that it has a content of 10% to 10%. 5. The composite material according to any one of claims 1 to 3, characterized in that it does not contain any organic acid cobalt salt.