JP2002080877A - Lubricant composition for steel filament, steel filament treated therewith, and rubber/steel filament composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant composition used for the surface treatment of steel filaments in drawing them for enhancing the adhesion between steel filaments and a rubber. SOLUTION: The lubricant composition for steel filaments is formed by blending at least one thiadiazole compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant composition used for wire drawing of a steel filament constituting a steel cord used as a reinforcing material for a rubber article, a steel filament treated with the lubricant composition, and the steel. The present invention relates to a rubber-steel filament composite using a filament.

[0002]

2. Description of the Related Art Conventionally, a steel cord has been used as a reinforcing material for rubber articles such as automobile tires, hoses, conveyor belts, and the like. Brass plating is applied. However, simple brass plating alone is not sufficient in corrosion resistance, adhesion stability, wet adhesion, heat-resistant adhesion and the like.

In order to solve such a problem, various methods have been proposed. As one of the methods, there is a method of treating the surface of a steel filament with a lubricant in a wire drawing step. For example, Japanese Patent Application Laid-Open No. 5-185 discloses a method in which a triazine thiol derivative is added to a lubricant to perform surface treatment.
136 and JP-A-6-341073. However, even the steel filament surface-treated in this way still has insufficient adhesion to rubber. On the other hand, as a coating rubber for steel filament, there is a method of using a rubber composition obtained by compounding an organic acid cobalt salt having an adhesion promoting action in rubber. However, the cobalt salt of an organic acid shows a high adhesive strength immediately after vulcanization, but has a disadvantage of deteriorating the rubber properties during heat aging.

[Problems to be solved by the invention]

[0004] The present invention solves the above-mentioned problems, and provides a lubricant composition used for wire drawing of a steel filament.
And a steel filament treated with the lubricant composition and a rubber-steel filament composite using the steel filament.

[Means for Solving the Problems]

The present inventor has studied various substances to be added to a lubricant composition used in a steel filament drawing process, and when a compound described below is added to the lubricant composition and treated, the adhesion to rubber is reduced. The present inventors have found that a steel filament excellent in the present invention can be obtained, and have completed the present invention.

[0006] The present invention resides in a lubricant composition for steel filaments, characterized by comprising at least one thiadiazole compound.

Preferably, the thiadiazole compound is a dimercaptothiadiazole.

As the dimercaptothiadiazoles, monosubstituted 2,5-dimercapto-1,3,4-thiadiazole or dimercaptothiadiazole is particularly preferred. As the latter monosubstitute, at least one selected from the group consisting of a sodium salt, a potassium salt, a lithium salt, an ammonium salt and a zinc salt is preferable.

Further, the present invention resides in a steel filament having the above lubricant composition layer on the surface, and a rubber-steel filament composite comprising the steel filament and a rubber composition.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, the steel filament is drawn by an ordinary wet drawing method using a wet type drawing machine. In this case, the steel wire is drawn through a die attached to a lubrication tank of a wire drawing machine to a predetermined wire diameter. As the steel filament, an unplated bare steel filament, a copper-plated steel filament, a brass-plated steel filament, a nickel-plated steel filament, or the like can be used. The steel filament is subjected to surface treatment during wire drawing by the lubricant composition in the lubrication tank, and a lubricant composition layer is formed on the surface of the steel filament.

The lubricant composition is a so-called emulsion type emulsion in which an extreme pressure inhibitor, an oil agent, an emulsifier, a foam inhibitor and the like are dispersed in a solvent. As these components, those usually used in wet drawing can be appropriately selected and used. The present invention is characterized in that at least one thiadiazole compound is blended in addition to the above-mentioned components to constitute a lubricant composition.

The thiadiazole compounds include thiadiazole, dimercaptothiadiazoles and monosubstituted products thereof. The thiadiazole compound has -S in the molecule.
It has an H group and can react with the double bond of the metal surface and the polymer to adhere them. As dimercaptothiadiazole, 2,5-dimercapto-1,3,3
4-Thiadiazole is preferred. In addition, examples of the monosubstitute include a sodium salt, a potassium salt, a lithium salt, an ammonium salt and a zinc salt.

The amount of the thiadiazole compound is 1 to 40 parts by weight based on 100 parts by weight of the lubricant composition.

In the present invention, the steel filament is drawn by a wet wire drawing machine and, at the same time, is subjected to a surface treatment with the lubricant composition having the above-described structure so that a lubricant composition layer, especially a lubricant, is formed on the surface of the steel filament. A coating layer of the thiadiazole compound in the components of the composition is formed. The formation mechanism of this coating layer is not clear, but is presumed to be as follows. That is, when the steel filament passes through the lubricant composition, the components of the lubricant composition, particularly the thiadiazole compound, are adsorbed on the surface of the steel filament. To form a coating layer.

[0015] The steel filament thus treated is used as a monofilament cord or as a steel cord obtained by twisting a plurality of strands. When twisting a plurality of strands, a partially untreated steel filament may be used. For use as a reinforcement for rubber articles, such cords are coated with a coating rubber to form a rubber-steel filament composite. The coating rubber is not particularly limited, and a commonly used rubber composition can be used. In the present invention, the lubricant composition layer at the interface between the rubber and the steel filament of the composite, that is, a coating layer of a thiadiazole compound is present,
Both are firmly adhered.

When the rubber-steel filament composite according to the present invention is used as a reinforcing material for a rubber article, since the adhesiveness between the rubber and the steel filament is excellent, the steel filament peels off from the rubber during use of the rubber article. Without this, the durability is remarkably improved.

[0017]

EXAMPLES The present invention will be described below based on examples and comparative examples, but is not limited thereto. According to the composition shown in Table 1, a lubricant composition and a rubber composition were prepared. First, brass plating (Cu: 63% by weight, Zn: 37
(% By weight) was passed through the above lubricant composition by a wet wire drawing machine and drawn to a wire diameter of 0.25 mm. A steel cord (1 × 5 structure) was prepared using the steel filament thus treated.
The steel cords were arranged in parallel at an interval of 12.5 mm, and the rubber composition was adhered from both sides thereof to prepare a rubber-cord composite sample.

After vulcanizing each sample at 160 ° C. for 10 minutes, the steel cord was subjected to ASTM-D-222.
9 and the pulling force at that time was measured. Table 1 shows the measurement results as initial adhesiveness, and Comparative Example 1 shows 1
The index is indicated by an index of 00. In addition, it shows that adhesive strength is so large that a numerical value is large, and initial adhesiveness is favorable.

Next, each sample was subjected to a vulcanization treatment at 160 ° C. × 20 minutes, and further subjected to a heat deterioration treatment at 60 ° C. × 10 days to measure the tensile strength of the rubber. The measurement results are shown in Table 1 by the index notation with Comparative Example 1 being 100.
In addition, it shows that intensity | strength is so large that a numerical value is large.

[0020]

[Table 1]

From the results shown in Table 1, it can be seen that each of the examples has no change in the rubber physical properties as compared with the comparative examples, and is excellent in the initial adhesiveness.

[0022]

As described above, by blending a thiadiazole compound in a lubricant composition and performing a surface treatment during wire drawing of a steel filament, a steel filament having excellent adhesion to rubber can be obtained. it can.
Further, when a composite of a steel filament and rubber thus treated is used as a reinforcing material for a rubber article, the organic acid cobalt salt can be reduced, so that the durability of the rubber article without impairing the adhesiveness is improved. Performance can be greatly improved.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10N 40:32 C10N 40:32

Claims (6)

[Claims] 1. A lubricant composition for steel filaments, comprising at least one thiadiazole compound. 2. The lubricant composition according to claim 1, wherein the thiadiazole compound is a dimercaptothiadiazole. 3. The lubricant composition according to claim 2, wherein the dimercaptothiadiazole is 2,5-dimercapto-1,3,4-thiadiazole. 4. The dimercaptothiadiazole is at least one monosubstituted dimercaptothiadiazole selected from the group consisting of sodium salt, potassium salt, lithium salt, ammonium salt and zinc salt. The lubricant composition according to any one of the preceding claims. 5. A steel filament having a lubricant composition layer containing at least one thiadiazole compound on its surface. 6. A rubber-steel filament composite comprising a rubber composition and a steel filament, and having at its interface a lubricant composition layer containing at least one thiadiazole compound.