JPS60171144A - Composite substance of rubber and metallic 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 applies to rubber and metal surfaces, particularly zinc, brass, bronze,
A rubber-metal material composite that has good adhesion to steel and shows little loss of adhesion between rubber and metal materials over a long period of time, so it is suitable for use as a material for the steel cord coating rubber layer of conveyor belts, etc. relating to things.

Conventionally, there have been various methods for bonding natural rubber, synthetic rubber, or a mixture of these rubbers to a metal core, especially a steel cord.A typical example is the use of an organic material such as cobalt naphthenate as an adhesive reinforcing agent. A method using a rubber composition containing a cobalt acid salt, a methylene donor such as hexamethylenetetramine and a methylene acceptor such as resorcinol,
Alternatively, a method using a rubber composition containing silica and silica is known, and these rubber compositions exhibit excellent vulcanization adhesion by direct adhesion to galvanized steel cords, brass-plated steel cords, etc. It has been known. However, with conventional composites of rubber and metal materials of this type, the adhesion between the rubber and metal materials is extremely high immediately after vulcanization, but it gradually deteriorates over time due to environmental influences such as heat and moisture. It has the following drawbacks.

In fact, when a composite of rubber and metal is used in steel cord conveyor belts, steel radial tires, etc., the above-mentioned phenomenon occurs; This results in a decrease in adhesive strength, and under harsh conditions, it may not be possible to withstand long-term use.

For this reason, it has been desired to suppress the deterioration of the adhesive force between rubber and metal materials over time and to improve the product life.

In view of the above circumstances, the present inventors have conducted intensive research on rubber-metal composites that exhibit less deterioration in adhesive strength over time between rubber and metal materials, and have found that direct adhesion to metal materials can be achieved through vulcanization. By adding metal powder such as zinc powder and liquid rubber to a possible rubber composition and vulcanizing it in direct contact with the metal material, the initial adhesive strength between the rubber and the metal material is high, and it can be used at high temperatures and high humidity. The present invention was completed based on the discovery that a composite of rubber and metal material with excellent moisture and heat resistant adhesion properties can be obtained with little decrease in adhesive strength even when used in an atmosphere for a long period of time. .

The present invention will be explained in more detail below.

The rubber-metal material composite according to the present invention includes a rubber composition that can be directly bonded to a metal material by vulcanization, zinc powder, aluminum powder, copper powder, nickel powder, magnesium powder,
1 selected from antimony powder, silicon powder and iron powder
A seed or two or more types of metal powder and liquid rubber are added, and a metal material is brought into direct contact with the mixture and vulcanized and bonded.

Here, the rubber composition contains raw material rubber and various compounding agents blended as desired. The raw material rubber used in the present invention is not particularly limited, and includes natural rubber, butadiene rubber, inbrene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene diene rubber, and the like. In the present invention, these raw material rubbers may be used alone or in combination of two or more. In addition, compounding agents include vulcanizing agents such as sulfur, crosslinking agents, vulcanization accelerators, reinforcing agents such as carbon black, white carbon, calcium carbonate, basic magnesium carbonate, clay, fillers, plasticizers, aging Examples include inhibitors, and one or more of these may be blended as necessary.

In addition to the above components, the rubber composition preferably contains a cobalt compound such as organic acid cobalt such as cobalt naphthenate, or a methylene donor such as hexamethylenetetramine and a methylene acceptor such as resorcinol, either alone or in combination. . In addition, a phenol resin, silica, etc. can also be blended as needed.

In this case, based on 100 parts by weight of the raw rubber component.

The cobalt compound is 0.05 to 1.5 parts by weight as cobalt content, and the methylene donor and methylene acceptor are each 1 part by weight.
It is preferable to use 1 to 15 parts by weight of the phenol resin, and 5 to 30 parts by weight of the silica.

In the present invention, one or more metal powders selected from zinc powder, aluminum powder, copper powder, nickel powder, magnesium powder, antimony powder, silicon powder, and iron powder and liquid rubber are added to the rubber composition. It is to be blended. Zinc powder is sometimes preferred as metal powder.

The blending amount of these metal powders is preferably 0.1 to 50 parts by weight, particularly 2 to 30 parts by weight, based on 100 parts by weight of the raw rubber, and within this range good adhesive effects and moist heat resistance effects can be obtained. In addition, if the amount of the metal powder blended is too large,
The upper limit is preferably 50 parts by weight since this may lead to deterioration of rubber properties.

The particle size of the metal powder is 500 pm or less, especially 15 pm or less.
It is preferable that the particle diameter is 0.01 Lm or less, particularly 50 IL.m or less. If the particle size is too large, it becomes a large foreign substance, which deteriorates the physical properties of the rubber, resulting in an undesirable situation. The liquid rubber has a viscosity average molecular weight of 500 to 60,000 and contains 1 to 2 carboxyl groups and/or hydroxyl groups per molecule.
The one containing 0 pieces is used. Among these liquid rubbers, liquid rubbers having carboxyl groups are polybutadiene-based or polyisoprene-based rubbers having a viscosity average molecular weight of 10,000 to 50,000.The number of carboxyl groups per molecule is 3 to 15. is preferably used. In addition, liquid rubber with hydroxyl groups has a viscosity average molecular weight of 10.0
00-50,000.Number of hydroxyl groups per molecule is 1-10
Polybutadiene-based or polyisoprene-based rubbers are preferably used. The amount of these liquid rubbers to be blended is preferably 1 to 60 parts by weight, particularly 2 to 20 parts by weight, based on 100 parts by weight of the raw rubber, and within this range good adhesive effects and moist heat resistance effects can be obtained.

Examples of metal materials that can be integrally vulcanized with the rubber composition include wires and cords made of steel, zinc, brass, bronze, galvanized steel, brass-plated steel, bronze-plated steel, etc., and are selected depending on the purpose. used.

Of the metal powder and metal material mentioned above, the most preferable combination in terms of effectiveness is zinc powder and zinc or galvanized metal material.

The rubber-metal material composite of the present invention is obtained by directly contacting a metal material with a rubber composition containing the metal powder and the liquid rubber and vulcanizing it, thereby forming a vulcanized rubber. A rubber-metal material composite is obtained in which a metal material is firmly adhered to the rubber-metal material composite.

In this case, the composite of the present invention has a high initial adhesive strength between the rubber (vulcanized rubber) and the metal material due to the combination of the metal powder and the liquid rubber, and can be left in a high temperature and humid atmosphere for a long period of time. The adhesive strength between rubber and metal materials does not deteriorate even when the rubber is used, and it has excellent wet heat stability and maintains sufficient adhesive strength for a long time.For this reason, it is used for conveyor belts, radial tires, etc. It is suitably used as a material.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

[Examples 1 to 4, Comparative Example 1] An adhesive rubber composition having the formulation shown in Table 1 was applied to 4 pieces of galvanized steel wire (0.39φ) arranged in parallel at 10 mm intervals under tension from both sides. The material was coated and vulcanized at 15'5℃ for 20 minutes, and the wire was glued to the center.The length was 240 mm, the width was 50 mm, and the thickness was 3 layers.
A rubber-metal composite was obtained.

Next, the composite was divided into 5 equal parts and used as pull-out test samples.

The pull-out test was performed using a length of 10 mm on the center side of the divided sample.
Leaving the rubber part of 1.5 mm thick, remove the rubber from the other parts to expose the wire, and add reinforcing rubber (10 mm x 50 mm x 4+) on both sides of the rubber part on the center side.
am) with cyanoacrylate adhesive and reinforced,
50 am in accordance with ASTM D-2229
The wire was pulled out at a tensile speed of l sin and its adhesive strength was evaluated.

In addition, the condition of the rubber adhering to the wire was evaluated using the following evaluation criteria, and the rubber adhesion was classified and evaluated based on the fracture shape.

Evaluation Criteria A 100% rubber adhesion (full rubber broken ml) Good 33,
75% /I ↑ c 50% 〃 D 25% 〃 , 1 80% // (Full metal surface exposed) Poor In addition, the adhesion strength and rubber adhesion in the pull-out test are the samples before thermal storage (initial sample) and This is about the sample after being stored under moist heat. In this case, moist heat storage is
Each sample was placed in an atmosphere of 70°C and 100% relative humidity.
This was done by leaving it for 4 days.

The results are shown in Table 1.

Table 1

Claims (2)

[Claims] (1) A rubber composition containing liquid rubber and one or more metal powders selected from zinc powder, aluminum powder, copper powder, nickel powder, magnesium powder, antimony powder, silicon powder, and iron powder. A composite of rubber and metal materials that is made by vulcanizing and adhering them in direct contact with metal materials. (2) Liquid rubber has a viscosity average molecular weight of 500 to 60.00
Claim 1 contains 1 to 20 carboxyl groups and/or hydroxyl groups per molecule in the range of 0.
Compounds described in Section.