JPH04317912A - Steel cord reinforced conveyor belt - Google Patents

Abstract

PURPOSE:To provide a steel cord reinforced conveyer belt which can be improved in shock resistance by improving the adhesion between the steel cord and rubber. CONSTITUTION:A conveyor belt is formed by embedding plural steel cords 4 in parallel in the longitudinal direction. The steel cord is constructed so that an adhesive rubber layer 1 is provided between an outer cover rubber layer 3 and an inner cover rubber layer 2, and a coat of a triazine thiol derivative is formed on the surface of the adhesive rubber layer 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyor belt reinforced with steel cords whose surface is coated with a triazinethiol derivative.

0002

[Prior art] Steel cord reinforced conveyor belt is
Generally used belts have an adhesive rubber layer between the inner and outer cover rubber layers, and a steel cord is embedded in this adhesive rubber layer so as to match the longitudinal direction of the belt. In order to improve the adhesive force between the steel cord and rubber, for example, Japanese Patent Publication No. 1983-33905 discloses an invention relating to an adhesive rubber composition for steel cords in which magnesium oxide is blended into a rubber composition containing cobalt organic acid. is disclosed, and Japanese Patent Publication No. 61 55468 relates to a steel cord/rubber composite in which a rubber composition is blended with one or more of resorcinol, hexamethylenetetramine, resorcinol formaldehyde condensate, and organic acid cobalt salt. An invention is disclosed.

0003

[Problems to be Solved by the Invention] However, the above-mentioned prior art is not suitable for use in high temperature and humid environments (for example, temperatures above 40°C,
When used at a relative humidity of 90% or higher, the rubber absorbs significant moisture, and this moisture absorption adversely affects the bonding interface between the steel cord and the rubber, reducing adhesive strength. For this reason, there are disadvantages in that the impact resistance is low, the steel cord is likely to break, and the product life is shortened.

[0004] Therefore, in order to improve this drawback,
JP-A-2-209930 and JP-A-2-2125
In Publication No. 24, 2 R 4,6 dithiol
An invention relating to a method for surface treatment of a steel wire is disclosed in which a film of an S triazine derivative is formed on the surface of the steel wire to improve corrosion resistance and adhesion to rubber. However, what is described in these publications is concerned with improving the adhesion between general rubber products and steel wires, and does not describe anything about its application to conveyor belts or its specific effects.

[0005] The present invention was made in view of the current situation, and the object thereof is to provide a steel cord-reinforced conveyor belt with improved impact resistance by improving the adhesion between the steel cord and rubber. It is about providing.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention has an adhesive rubber layer between an outer cover rubber layer and an inner cover rubber layer, and the adhesive rubber layer has the following: A steel cord-reinforced conveyor belt characterized in that a plurality of steel cords each having a surface coated with a triazinethiol derivative represented by the chemical formula are buried in parallel in the longitudinal direction.

[0007]

[Chemical 2]

[0008] (However, R is OR', SR',
NHR', N(R')2;R' is H, alkyl group, alkenyl group, phenyl group, phenylalkyl group, alkylphenyl group or cycloalkyl group; M is H,
Na, K, Li, NH4, 1/2 Mg, 1/2 Ca
, 1/2 Ba, 1/2 Zn, aliphatic 1st class, aliphatic 2
A steel cord having a coating of a triazine thiol derivative (representing a class, tertiary amine, quaternary ammonium salt or phosphonium salt) formed on the surface is prepared by filling a bath of a wet wire drawing machine with a lubricant containing the above triazine thiol derivative, A die is attached to this bathtub, steel wires of an appropriate diameter are drawn through the die at an appropriate drawing speed and ratio, and the predetermined number of wires after drawing are twisted using a general method. You can get it.

[0009] In the present invention, "steel cord" refers to
galvanized steel cord, copper plated steel cord,
This includes brass-plated steel cord, nickel-plated steel cord, tin-plated steel cord, copper-tin-plated steel cord, cobalt-plated steel cord, non-plated steel cord, etc.

The above-mentioned lubricant is a so-called emulsion type lubricant, and this lubricant contains the above-mentioned triazinethiol derivative, an extreme pressure inhibitor, an oily agent, an emulsifier, a foaming inhibitor, etc., and these components are mixed with water. (neutral or alkaline), or an emulsion dispersed in a glycol such as an ethylene glycol derivative, polyethylene glycol or diglyme. In addition to the above-mentioned components, it may also contain, for example, an iron rust preventive agent and a preservative and fungicide. This lubricant can be used as is during processing or
It is used after being diluted within 5 times, preferably 5 to 10 times.

The triazinethiol derivatives of the present invention include 2,4,6 trithiol S-triazine,
2 phenyl 4,6 dithiol S-triazine, 2 methoxy 4,6 dithiol
S-triazine, 2-ethoxy 4,6 dithiol
S Triazine, 2 Phenoxy 4/6
Typical examples include dithiol S triazine. The content of the triazinethiol derivative in the lubricant (undiluted) is preferably 0.001 to 20% by weight, preferably 0.01 to 5% by weight.

The extreme pressure inhibitor has the effect of preventing seizure of the wire during wire drawing, and examples of the extreme pressure inhibitor that can be used include ethylenediamine phosphate and ethylenetriamine phosphate. . The content of the extreme pressure inhibitor in the lubricant (undiluted) is preferably 0.1 to 15% by weight, preferably 1 to 10% by weight.

[0013] The oily agent has the effect of preventing the wire from seizing during wire drawing and improving the wettability, and the oily agent is generally made of amines of fatty acids, reaction products of fatty acids and epoxy compounds, or Reaction products of fatty acid esters and epoxy compounds can be used. The content of the oily agent in the lubricant (undiluted) is preferably 0.1 to 20% by weight, preferably 1 to 15% by weight.

[0014] The emulsifier has the effect of emulsifying an extreme pressure inhibitor, an oily agent, a foam suppressor, etc. in water, and generally a reaction product of an alkylamine and an epoxy compound can be used as the emulsifier. The content of emulsifier in the lubricant (undiluted) is 0.1 to 10% by weight, preferably 0.5 to 10% by weight.
5% by weight is good.

The foaming inhibitor has the effect of inhibiting foaming of the emulsion, and mineral spirits such as decane and octane can be used as the foaming inhibitor. The content of the foam suppressor in the lubricant (undiluted) is preferably 0.1 to 10% by weight, preferably 0.5 to 5% by weight.

[0016] The rubber compound of the present invention is not particularly limited, but
Various rubbers, fillers, softeners, crosslinking agents, crosslinking accelerators, etc., to which lubricants, anti-aging agents, adhesion promoters (adhesion promoters) can be added, if necessary, can be used.

[0017] As the rubber, for example, natural rubber (NR)
, isoprene rubber (IR), butadiene rubber (BR),
Styrene butadiene rubber (SBR), acrylonitrile butadiene copolymer rubber (NBR), ethylene propylene copolymer rubber (EPM), ethylene propylene diene copolymer rubber (EPDM), silicone rubber, butyl rubber (IIR), chloroprene rubber (CR) , fluororubber (
FKM) etc. can be used.

[0018] Fillers are added for the purpose of increasing the volume or reinforcing the material. Examples of fillers include carbon black, calcium carbonate, and silicates. The amount of filler is
It is preferably 5 to 200 parts by weight, preferably 30 to 100 parts by weight, per 100 parts by weight of rubber.

A softener is added to improve the processability and moldability of the rubber. Examples of the softening agent include fatty acid ester plasticizers, chlorinated paraffin, process oil, naphthenic oil, and the like. The blending amount of the softener is 100 parts by weight or less, preferably 5 to 50 parts by weight, based on 100 parts by weight of rubber.

[0020] The crosslinking agent is blended in order to exhibit elasticity of the rubber material. The crosslinking agent used varies depending on the type of rubber, but typical examples include sulfur and dicumyl peroxide. The amount of crosslinking agent mixed varies depending on the type of rubber, so it cannot be absolutely limited, but it is generally 0.1 to 10 parts by weight per 100 parts by weight of rubber.
Parts by weight are appropriate.

[0021] A crosslinking accelerator is added to promote the action of the crosslinking agent. Examples of crosslinking accelerators include MgO, Z
Examples include metal activators such as nO. The amount of the crosslinking accelerator varies depending on the type of rubber and crosslinking agent, so it cannot be absolutely limited, but in general, 0.1 to 20 parts by weight per 100 parts by weight of rubber is suitable.

A lubricant is added to improve the flow of the rubber compound during adhesion. Examples of the lubricant include stearic acid, paraffin, and wax. The lubricant is generally used in an amount of 0.0% per 100 parts by weight of rubber.
It is blended in an amount of 1 to 5 parts by weight.

Anti-aging agents are included to prevent deterioration of the adhesive composite. Examples of anti-aging agents include phenylene diamine anti-aging agents and phenol anti-aging agents. The anti-aging agent is generally added in an amount of 0.1 to 5 parts by weight per 100 parts by weight of rubber.

Examples of adhesion aids include cobalt salts,
Examples include resorcinol. The adhesion aid is 0.1 to 20 parts by weight, preferably 0.5 to 20 parts by weight per 100 parts by weight of rubber.
5 parts by weight is blended.

In the steel cord reinforced conveyor belt of the present invention, a plurality of steel cords coated with a triazinethiol derivative are placed between two adhesive rubber sheets parallel to the longitudinal direction of the belt at regular intervals. Further, this adhesive rubber sheet is sandwiched between inner and outer cover rubber sheets, and then this multilayer rubber is vulcanized under heat and pressure according to a conventional method.

[0026]

[Function] The steel cord reinforced conveyor belt according to the present invention constructed as described above has a dense and strong coating of triazinethiol derivative on the surface of the steel cord, so it has good adhesion to rubber. It has extremely good impact resistance.

[0027]

[Examples] Examples of the present invention will be described below.

The composition of the adhesive rubber was prepared as shown in Table 1 below, and the composition of the inner cover rubber and outer cover rubber was prepared as shown in Table 2 below.

[0029]

[Table 1]

[0030]

[Table 2]

[0031] Then, a bath of a wet wire drawing machine (not shown) is filled with a lubricant consisting of a triazine thiol derivative, an extreme pressure inhibitor, an oily agent, an emulsifier, and a foaming suppressant prepared to a predetermined concentration, and the bath is filled with A galvanized steel wire was drawn in the provided die at an appropriate drawing speed and ratio to obtain a wire having a triazinethiol derivative coating formed on its surface. Next, this strand was twisted using a general buncher-type twisting machine (not shown) to obtain a steel cord having a 7×7 twisted structure. After that, this steel cord was sandwiched between two adhesive rubber sheets having the above composition, and then this adhesive rubber sheet was further sandwiched between an inner cover rubber sheet and an outer cover rubber sheet and vulcanized under heat and pressure. A steel cord reinforced conveyor belt with the structure shown was obtained. Figure 1
, 1 is an adhesive rubber layer, 2 is an inner cover rubber layer, and 3 is an adhesive rubber layer.
is an outer cover rubber layer, and 4 is a steel cord. In addition, as a comparative example, the lubricant was removed from the bathtub of the wet wire drawing machine, and a galvanized steel wire was drawn using the same die.
A steel wire without a triazine thiol derivative coating formed on the surface was obtained, and this wire was twisted using the same buncher-type twisting machine as described above to obtain a steel cord with the same 7×7 twisted structure, and this steel cord was used. A conveyor belt having a structure similar to that shown in FIG. 1 was manufactured using the following steps. The width W1 of this conveyor belt is 600 mm, the thickness of the inner cover rubber layer and the outer cover rubber layer are each 6 mm, the diameter of the steel cord is 6.1 mm, and the buried pitch P of the steel cord is 1.
It is 5mm.

[0032] The triazinethiol derivative in which the film was formed on the surface of the galvanized steel cord in Example 1 has the following chemical formula, where R is SH,
Example 2 is a product with the same chemical formula, where R is SH and M is Na. Example 3 is a product with the same chemical formula, where R is N(C4 H9)2 and M is H. The following was used.

[0033]

[C3]

Test pieces of predetermined shapes were taken from the conveyor belts according to Examples 1 to 3 and the conveyor belt according to the comparative example, and the initial adhesion strength and dry heat aging (160° C.
Adhesion strength after immersion in boiling water (80°C x 3 weeks)
The adhesive strength of the samples was measured, and Table 3 below was obtained.

[0035]

[Table 3]

As is clear from Table 3, the initial adhesive strength, the adhesive strength after dry heat aging, and the adhesive strength after immersion in boiling water in Examples 1 to 3 were all higher than those of the comparative example, and the present examples were higher than those of the comparative example. It can be seen that the material according to the invention has excellent adhesive strength.

For the conveyor belts of Examples 2, 3, and Comparative Examples, impact test pieces of predetermined shapes were taken and impact tests were conducted. The impact tester is shown in Figure 2.
Using this impact tester, a lifting magnet 7 was attached to the hook 6 of the electric chain hoist 5, and the lifting magnet 7 attracted the weight 8, and the test was carried out using this impact tester. The lifting magnet 7 was demagnetized and only the weight 8 was dropped with a height of 3000 mm from the test piece, and the number of times the weight 8 was dropped until it penetrated the test piece installed at the lower part of the testing machine was determined. The load of the weight 8 was 450 kg, the width (W2) of the weight 8 and the test piece was 400 mm, and the impact portion 9 had a triangular protruding piece as shown in the figure. The results of this impact test are shown in Table 4 below, expressed as an index for the number of times the weight was dropped in the case of the comparative example.

[0038]

[Table 4]

As is clear from Table 4, it can be seen that the material according to this example has excellent impact properties.

[0040]

Effects of the Invention The steel cord reinforced conveyor belt according to the present invention has excellent impact resistance because the adhesion between the steel cord and the rubber is good even under high temperature and high humidity conditions. We can provide long life steel cord reinforced conveyor belt.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a steel cord reinforced conveyor belt according to the invention.

FIG. 2 is a front view of the impact tester.

[Explanation of symbols]

1. Adhesive rubber layer 2.Inner cover rubber layer 3.Outer cover rubber layer 4. Steel cord

Claims (1)

[Claims] Claim 1: An adhesive rubber layer is provided between an outer cover rubber layer and an inner cover rubber layer, and a plurality of adhesive rubber layers are formed on the surface of the adhesive rubber layer with a coating of a triazinethiol derivative represented by the following chemical formula. A steel cord reinforced conveyor belt characterized by steel cords buried parallel to the longitudinal direction [Chemical formula 1] (where R is OR', SR', NHR'
, N(R')2;R' is H, alkyl group, alkenyl group, phenyl group, phenylalkyl group, alkylphenyl group or cycloalkyl group; M is H, Na, K, L
i, NH4, 1/2 Mg, 1/2 Ca, 1/2 B
a, 1/2 Zn, aliphatic primary, aliphatic secondary, tertiary amine, quaternary ammonium salt or phosphonium salt)