JPS5851146A - Steel cord-rubber composite material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber composition and a composite comprising the rubber composition and a brass-plated steel cord.

In composite materials such as steel tires, belts, and reinforced hoses, the metal material is coated with zinc, copper, copper alloys (brass, bronze), etc. to improve the adhesion between the metal material and the rubber composition. Generally, resorcinol-formaldehyde resin, organic cobalt salt, etc. are added as adhesion aids.

However, the composite material obtained in this manner does not have sufficient adhesion stability in the unvulcanized state and the vulcanized state of the rubber composition, especially in high temperature and high humidity conditions. was there. For this reason, tires and the like that are exposed to particularly severe conditions are susceptible to damage caused by the adhesion t41H between the steel cord and rubber.

The present invention solves these problems and provides a rubber composition suitable for a composite material, and a composite material made by adhering the rubber composition to a brass-plated steel cord with a specific copper ratio. The gist is 100 parts by weight of base rubber and 2 to 50 parts by weight of liquid rubber.

A rubber composition containing 05 to 10 parts by weight of an organic gobalt salt and 2 to 8 parts by weight of sulfur, and a rubber composition containing a copper ratio of 60 to 6.
It consists of a composite phase formed by adhering to a brass-plated steel cord by the diffusion method with a copper ratio of 6% or the cyanide method with a copper ratio of 57-63%.

The sample rubber used in the present invention is not particularly limited, and may be one that has been conventionally used for this type of steel cord-rubber composite, such as natural rubber or a mixture of natural rubber and synthetic polyisoprene rubber. do it.

The liquid rubber used in the present invention is preferably a polyisoprene rubber having a viscosity average molecular weight (Mv) of 150'00 to 50,000 and a number of carboxyl groups per molecule of 3 to 15. Polyisoprene rubber (manufactured by Isoprene Chemical Co., Ltd.) and the like.

The amount of the liquid rubber blended is 2 to 50 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the sample rubber. If the amount of liquid rubber is less than 2 parts by weight, good adhesion cannot be obtained, and if it is more than 50 parts by weight, the processability of the unvulcanized rubber will be impaired.

Examples of the organic cobalt salt used in the present invention include cobalt stearate, cobalt naphthenate, cobalt octy(3)alate 11, cobalt versatate, and the like, with cobalt stearate being particularly preferred.

The amount of organic cobalt salt to be blended is 0.5 to 10 parts by weight per 100 parts by weight of the base rubber, and if it is less or more than this, generally no improvement in adhesion can be expected.

The amount of sulfur blended is usually 2 to 100 parts by weight of the base rubber.
There will be 8 layers and 1 intersection. If the amount of sulfur compounded is less than this, sufficient adhesion IA cannot be obtained, and if it is too large, the tensile strength and elongation are extremely low, and sufficient physical properties cannot be obtained.

In addition to the above ingredients, the rubber composition according to the present invention may appropriately contain conventional additives such as anti-aging agents, zinc white, carbon black, and vulcanization accelerators.

The steel cord used in the steel cord-rubber composite material according to the present invention has a copper ratio of 60 to 66% (diffusion method) and has a copper ratio of 5.
Brass plated at 7-63% (cyan method).

The crystal structure of a brass layer plated with a copper ratio within the above range contains a mixture of α and β layers, which has a positive effect on the adhesion between rubber and steel, especially under high temperature and humidity conditions (4). In other words, when the copper ratio is 60% or less in the case of the diffusion method and 57% or less in the case of the cyan method, the β layer increases and the α layer almost disappears, resulting in a decrease in adhesion; If it becomes more than 66%, and if it becomes more than 63% in the case of the cyan method, the β layer will almost disappear and the adhesion stability will drop significantly.

The plating layer typically has a thickness of about 0.1-0.8 μm.

By combining the rubber composition obtained in the above manner with a brass-plated steel cord, the workability in the manufacturing process was greatly improved as the adhesion of the unvulcanized rubber was sufficiently maintained. Not only this, but also excellent adhesion after vulcanization, particularly excellent long-term adhesion stability under high temperature and humidity conditions, can be obtained at the same time, so that the above-mentioned drawbacks that have been a problem in the past are solved.

Although the present invention was developed primarily for tires for automobiles and the like, it can be widely used in metal-rubber composite products that require adhesive stability, such as conveyor belts, reinforced hoses, and anti-splint materials.

Hereinafter, the present invention will be explained by examples.

Eleven types of rubber compositions were prepared according to the formulations shown in Example Table-1. ' l) Natural rubber 2) Kuraray Rubber Non-chemical polyisoprene rubber: Kuraprene L I R-4,101 Viscosity average molecular weight i 25000, Specific gravity i 0.924° Melt viscosity (38
°C, Type B viscometer) i1800. Carboxyl group; about 1
0 pieces/molecule) 3) 2,2.4-1-rifthyl-1,2-cyhydrogynoline 4) CZ (N-cyclohexyl-2-benzothiazylsulfenamide) manufactured by Sumitomo Chemical Co., Ltd. Obtained rubber composition The physical properties of the product were measured after vulcanization (140°C for 940 minutes) and the results are shown in Table 2.

Table 2 Rubber sheets 1- (thickness 3 body x width 501 + I + I + x length 100
1' to 11' are attached to steel tire cords ((7) 1 X 310.201-I Pressure vulcanization was carried out at C for 30 minutes. The obtained composite material was subjected to a peel test to examine the adhesion of the rubber. The above rubber sheets were lined up with no gaps between them, and after being attached to a steel cord and pressurized (2 kg/1-rn), a peel test was conducted to examine the adhesiveness of the rubber sheets. These results are shown in Table 3.

(8) 1) The amount of rubber deposited on the steel cord with peeling i is expressed as %.

The values in the table represent (unaged rubber adhesion amount)/(rubber adhesion after aging for 500 hours+it).

2) Comparison of force for peeling. ◎: 1.5-31 (g
/ Cm +○: 0.5-1.5 kg/cm,
△: 0.5 kg/an or less Next, tires 2, 3, 8.9 and IO were made using a steel cord plated with brass at a copper ratio of 63% by diffusion method. 8゜9゜: bi10
(1755R14) and put these tires under a load of 550 ky, including 1. -JE 2.2 ky/cn+2
, Speed 1, Condition 1: 20 Km/h, the machine was run for 30,000 Km on Gekyu Dest, and Steel Co. 1-
The amount of rubber layer applied to the breaker and the depth of fracture at the breaker edge were measured. The measurement results are shown in Table-4.

Table-4 Patent applicant Jumu Rubber Industries Co., Ltd. (11)

Claims (1)

[Claims] ■. Brass-plated steel cord, 2. Base rubber 1.
A steel cord-rubber composite material formed by adhering a rubber composition containing 0.00 parts by weight, 2 to 50 parts by weight of liquid rubber, 0.5 to IO parts by weight of an organic cobalt salt, and 2 to 8 parts by weight of sulfur. 2. Liquid rubber has a viscosity average molecular cylinder of 15,000 to 50,000
．． 2. The composite material according to item 1, which is a polyisoprene rubber having 3 to 15 carboxyl groups per molecule. 3. The composite material according to item 1, wherein the organic cobalt salt is cobalt stearate.