JPH11181149A - Rubber composition for metal composition material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition which can give a metal composite material which is suppressed in the formation of cracking due to separation without adversely affecting the rubber composition itself and without being influenced by the state of the surface of the metal, such as the presence of a plating by including a natural rubber and/or a synthetic rubber, a zinc salt of an organic acid, and sulfur. SOLUTION: This composition is obtained by compounding 100 pts.wt. at least one rubber component comprising a natural rubber and/or at least one synthetic rubber selected among an isoprene rubber, a styrene/butadiene rubber, a butadiene rubber, an ethylene/propylene rubber, and a butyl rubber with a sulfur vulcanizing system comprising 0.5-7 pts.wt. sulfur and 0.3-15 pts.wt. zinc salt of an organic acid such as zinc diacrylate. The organic acid which constituents the organic acid zinc salt is exemplified by acrylic acid. The composition has excellent adhesiveness and can be applied to a coating rubber for steel cords or an end cover rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a composite with a metal, and is particularly suitably used as a cover rubber for a reinforcing steel cord of a pneumatic tire or the like.

[0002]

2. Description of the Related Art Conventionally, a rubber composition for a composite with a metal, for example, when the metal is a steel cord, is compounded with an organic cobalt in order to enhance the adhesiveness with the metal, Means such as excessive addition of sulfur have been adopted, but the former is not only concerned with the effect on the working environment, but also has a problem that the heat aging resistance of the rubber composition itself is reduced, and On the other hand, the latter has inconvenience such as quickening of the deterioration of the rubber composition itself. On the other hand, measures have been taken, such as brass plating, to improve the adhesion of the steel cord to the rubber composition, but the cut surface at the end of the cord is not plated, so the adhesive strength is low. There were also inconveniences such as lowering. If the bonding was insufficient, the bonded portion was peeled off (separation occurred), which became the core of a crack in the rubber article as the product, and affected the durability of the rubber article.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a good working environment, without adversely affecting the rubber composition itself, without being affected by the condition of the metal surface such as the presence or absence of plating, and improving the adhesive force. An object of the present invention is to improve the durability of products such as pneumatic tires by suppressing the occurrence of cracks due to separation.

[0004]

In order to achieve the above object, the present invention has the following arrangement. (1) At least one of natural rubber and synthetic rubber is used as a rubber component, and 0.3 parts by weight or more of an organic acid zinc is added to 100 parts by weight of the rubber component, and sulfur is added to 0.5 part by weight.
A sulfur vulcanization system is used by mixing up to 7 parts by weight. (2) The synthetic rubber is isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (B
R), ethylene propylene rubber (EPDM), and butyl rubber (IIR). (3) The organic acid of the organic acid zinc is acrylic acid. (4) It is applied as a coating rubber or an end cover rubber of a steel cord. Here, "end cover rubber" refers to rubber that covers the end of a reinforcing steel cord such as a pneumatic tire.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The organic acid zinc compounded in the rubber composition of the present invention has a function of bonding (crosslinking) polymers and a function of bonding a polymer and a metal in the rubber composition. This eliminates the need to apply brass plating to the metal, mix organic cobalt, or mix high amounts of sulfur. The fact that the metal does not require brass plating means that, for example, the cut surface at the end of the cord is also adhered to the rubber composition, so that poor adhesion at the end face of the cord is also eliminated. Further, examples of the organic acid constituting the organic acid zinc usable in the present invention include acrylic acid and the like,
Further, in the present invention, at least 0.3 parts by weight of an organic acid zinc such as zinc diacrylate is added to 100 parts by weight of the rubber component.
It is specified that the compounding should be performed in parts by weight, but if it is less than this, the effect of the compounding cannot be obtained. The upper limit of the amount is
It is preferred to use 15 parts by weight, but if it is added more than this, there is no disadvantage in terms of effect, but it is economically disadvantageous. Furthermore, sulfur is blended in an amount of 0.5 to 7 parts by weight to obtain a sulfur vulcanization system. If the amount is less than 0.5 part by weight, the vulcanization (adhesion) rate is slow, and productivity is significantly deteriorated. Excess is because the heat aging resistance of the rubber composition itself is significantly reduced.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on embodiments. A steel cord embedded in a rubber composition having the composition shown in Table 1.
A sample of 0 × 5 × 1.5 cm was prepared, and the adhesive pulling force was measured. The steel cord was brass-plated, immersed in an ammonium sulfate solution for 16 hours, the plating was removed, and the one washed with distilled water was made into a 1 × 3 twisted structure. Eight at 1 cm intervals, sample thickness It was buried in the center in the direction. The vulcanization conditions are press vulcanization at 145 ° C. for 30 minutes. The measurement of the adhesive pull-out force was based on ASTM D2229, and the force required for pulling out the steel cord at 200 ± 30 mm / min by a tensile tester was determined and defined as the value of the adhesive force.

[0007]

[Table 1]

SBR: manufactured by Asahi Kasei Kogyo Co., Ltd., trade name Toughden 2000R BR: manufactured by Nippon Synthetic Rubber Co., Ltd., trade name BR01 Zn diacrylate: manufactured by SARTOMER, trade name SALET 633 Vulcanization accelerator (DZ): Ouchi Noxeller DZ (N, N-dicyclohexyl-2-manufactured by Shinko Chemical Industry Co., Ltd.)
Benzothiazolylsulfenamide) Vulcanization accelerator (CZ): manufactured by Ouchi Shinko Chemical Co., Ltd., trade name Noxeller CZ (N-cyclohexyl-2-benzothiazylsulfenamide) Antioxidant: Ouchi Shinko Chemical Nocrack 6C (N- (1,3-dimethylbutyl) -N'-
Phenyl-p-phenylenediamine)

[0009]

As described above, according to the present invention,
Good working environment, without adversely affecting the rubber composition itself, without being affected by the state of the metal surface such as the presence of plating, excellent in adhesive strength, suppressing the occurrence of cracks due to separation, The durability of a product using a metal-rubber composition composite such as a pneumatic tire can be improved.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23/16 C08L 23/16 23/22 23/22 // C08K 13/02 C08K 13/02 (C08K 13/02 5: 098 3:06) B29K 7:00 9:00 19:00

Claims (4)

[Claims] At least one of natural rubber and synthetic rubber is used as a rubber component, and at least 0.3 part by weight of an organic acid zinc is added to 100 parts by weight of a rubber component, and sulfur is added at 0.5 to 7 parts by weight. A rubber composition for a composite with a metal, wherein a sulfur vulcanization system is used by blending parts by weight. 2. The synthetic rubber is isoprene rubber (IR),
The rubber composition for a composite with a metal according to claim 1, wherein the rubber composition is styrene-butadiene rubber (SBR), butadiene rubber (BR), ethylene propylene rubber (EPDM), and butyl rubber (IIR). 3. The rubber composition for a composite with a metal according to claim 1, wherein the organic acid of the organic acid zinc is acrylic acid. 4. The rubber composition for a composite with a metal according to claim 1, wherein the rubber composition is applied as a coating rubber for a steel cord or an end cover rubber.