JP2002011519A - Wire drawing method for steel wire and steel wire for rubber article reinforcement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new manufacturing method, with which excellent initial adhesiveness can be imparted to a steel wire under high productivity and a low cost. SOLUTION: When a brass-plated steel wire is subjected to drawing, a wet type lubricant which contains zinc, further one either cobalt or nickel or both of them are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing a steel wire used as a reinforcing material for rubber articles such as pneumatic tires and industrial belts.

[0002]

2. Description of the Related Art A pneumatic tire, which is a typical example of a rubber article, has a steel cord formed by twisting a plurality of brass-plated steel wires on a belt or a carcass or a single wire of a steel filament. Is applied with rubber and is mainly reinforced with steel cord. In order to use the steel cord as a reinforcing material for the tire, it is necessary to securely adhere to the rubber covering the steel cord. For this reason, the peripheral surface of the wire constituting the steel cord is subjected to brass plating. I have. Usually, this steel wire is subjected to brass plating, then drawn to a predetermined diameter, and supplied to manufacture of a cord.

[0003] This brass-plated steel wire is drawn by a wet-type method using, for example, a slip-type multi-stage drawing machine and a wet lubricant containing an oil agent, an extreme pressure inhibitor and a surfactant. When wire drawing is performed, the friction between the die and wire during wire drawing is reduced by using a zinc complex of phosphate ester etc. as an extreme pressure prevention film during wire drawing, resulting in damage to the die and wire. Has been suppressed. This ingenuity has played a very important role in increasing the productivity of steel wires.

[0004] The adhesion between the brass-plated steel wire and the rubber is mainly obtained by the reaction between the copper in the plating and the sulfur in the rubber, but the extreme pressure prevention film remains on the wire surface. In this case, the extreme-pressure prevention film inhibits the reaction between copper and sulfur, leading to poor initial adhesion especially during rubber vulcanization. Therefore, conventionally, this problem has been solved by adding cobalt or nickel which promotes the diffusion of copper into the rubber.

[0005]

However, the addition of cobalt or nickel to rubber has caused a new problem of reducing the vulcanization reactivity and durability of rubber. That is, the added cobalt or nickel is effective in accelerating the adhesive reaction, but these added components bleed out from the unvulcanized rubber, so-called blooms. The workability at the time of bonding the vulcanized rubber sheet is reduced, and the adhesion and adhesion between the unvulcanized rubber sheet and the surrounding rubber are hindered. It causes a cutting reaction, that is, reversion, and also causes a decrease in tire durability.

[0006] Further, since cobalt metal salts and the like added to rubber are expensive, reducing cobalt and the like in the rubber coated with the steel wire not only avoids the above-mentioned problems with rubber, but also reduces the rubber. This is advantageous in reducing the compounding cost, and is important from the viewpoint of resource saving.

Accordingly, in order to avoid the above-mentioned problems with unvulcanized rubber, problems with rubber after vulcanization, and problems with cost, it is necessary to reduce the amount of cobalt or nickel to be added or not to add it. Is preferred, but deterioration of the rubber adhesiveness again becomes a problem. In other words, if the rubber adhesion, especially the initial adhesion, of the steel wire is improved, it is possible to reduce or omit cobalt and nickel added to the rubber.

Accordingly, an object of the present invention is to propose a novel method of manufacturing a steel wire capable of imparting excellent initial adhesion to a steel wire with high productivity and low cost.

[0009]

That is, the gist of the present invention is as follows. (1) Wet drawing of a brass-plated steel wire is performed by using a wet lubricant containing zinc and further containing one or both of cobalt and nickel. Line method.

(2) In the above (1), the wet lubricant contains at least 0.30 g / l of zinc, and further contains at least 0.30 g of one or both of cobalt and nickel.
/ 1 / l or more.

(3) In the above (2), the wet lubricant contains at least 0.35 g / l of zinc, and further contains one or both of cobalt and nickel in a total amount of 0.40 to 0.40 g / l.
A method for drawing a steel wire, wherein the composition has a composition containing 0.80 g / l.

(4) A steel wire for reinforcing rubber articles obtained by the wire drawing method according to any one of (1) to (3). In the above description, the component composition of the lubricant is that at the start of drawing. Each component is present in the aqueous solution mainly as a complex or a single ion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a steel wire according to the present invention will be described with reference to an example of wet continuous drawing performed by using a multi-slip wet drawing apparatus shown in FIG. In the present invention, since the steel wire is drawn by a wet method, there is no need to particularly limit the type of the steel wire as long as it is a wet method, and either a single drawing or a continuous drawing may be used.

In the multistage slip type wet drawing apparatus shown in FIG. 1, a steel wire 3 is interposed between the multistage drive capstans 2a and 2b arranged in the lubricating liquid tank 1 between the respective stage drive capstans. In the process of alternately bridging, the wire is drawn by the dies 4 for each stage, and is sent to the winding process from the drive capstan 6 outside the lubricating liquid tank 1 through the final dies 5.

In the above wet drawing, the wet lubricant in the lubricating liquid tank 1 contains zinc in addition to ordinary wet lubricant components such as an oil agent, an extreme pressure inhibitor and a surfactant, and further contains cobalt. It is important to contain either one or both of nickel and nickel.

In this wet lubricant component, zinc is first added to suppress the abrasion of the wire drawing die, which affects so-called wire drawability, and to realize uniform wear. That is, as shown in FIG. 2, the relationship between the zinc concentration and the die life in wet wire drawing shows that when the zinc concentration is 0.30 g / l or more, particularly 0.35 g / l or more, the die life is improved. The effect is observed. Therefore, it is preferable to add zinc to the wet lubricant at 0.30 g / l or more, particularly preferably 0.35 g / l or more.

On the other hand, if the zinc concentration exceeds 0.50 g / l, the generation of zinc-containing precipitates increases, and the zinc concentration becomes unstable. Therefore, the zinc concentration should be 0.50 g / l or less. Is preferred. During the use of the lubricant (during wire drawing), a certain amount of zinc dissolves from the brass plating component. It is desirable to control the concentration by means such as the precipitation of.

Similarly, a certain amount of copper is dissolved in the lubricant from the brass plating during the use of the lubricant. However, as shown in FIG. 3, the relationship between the copper concentration and the die life is 0.3%.
When the amount exceeds 0 g / l, the life of the dice decreases. In particular, when the amount exceeds 0.50 g / l, the life of the die decreases significantly. Therefore, it is recommended to limit the concentration of copper to 0.50 g / l or less, more preferably 0.30 g / l or less, even during use, by means such as electrodeposition.

In the experiment shown in FIG. 2, only the zinc concentration in the lubricant was variously changed, and a 1.72 mm diameter brass-plated wire was 0.30 mm in diameter using the lubricant having each zinc concentration. Unwinding speed 800m / mi
n, the final wire diameter, that is, the weight of the wire drawn until the diameter of the final die became 0.005 mm thicker from the start of wire drawing, was investigated, and the zinc concentration of which value was the maximum was 0.42 g / l. The index when the inspection result at the time of was 100 was defined as the die life.

Next, cobalt and nickel are added to improve rubber adhesion in brass plating of steel wire. That is, as shown in FIG. 4, similarly to the above, as shown in the result of examining the relationship between the cobalt concentration in the lubricant and the die life, it can be seen that the cobalt concentration has almost no correlation with the die life, that is, the drawability.

On the other hand, the relationship between the cobalt concentration in the lubricant and the rubber adhesiveness of the wire, as shown in FIG. 5, shows that the adhesiveness of the wire greatly depends on the cobalt concentration. That is, when the cobalt concentration is 0.40 g / l or more, adhesiveness is secured even by vulcanization for a relatively short time, and excellent adhesiveness is obtained. Further, it can be seen that even if the cobalt concentration exceeds 0.80 g / l, there is almost no further improvement in adhesiveness. Therefore, it is preferable that cobalt is added to the wet lubricant at 0.40 g / l or more, and the upper limit is 0.1 from the viewpoint of cost reduction.
Advantageously, it is 80 g / l. It is desirable to keep this range at all times by appropriately supplementing cobalt during use.

The rubber adhesion ratio is obtained by performing a rubber adhesion test on a drawn steel wire in accordance with a rubber adhesion test method specified in reference to JIS G3510 (1992). is there.

As described above, the effects of cobalt on drawability and adhesiveness shown in FIGS. 4 and 5 are the same for nickel, and both can be used alone or in combination under the same action and effect.

[0024]

EXAMPLE 4. Diameter containing about 0.82% by weight of carbon.
After repeatedly dry-drawing a 5 mm high-carbon steel wire until its diameter becomes about 1.39 mm, the wire prepared by applying a patenting process and a brass plating process was prepared as shown in FIG. Using various lubricants having different additive component ranges shown in Table 1, a diameter of about 0.2
Wet drawing was performed until the thickness became 1 mm. The lubricant is
Fatty acids, phosphoric acid, phosphate esters, amines, mineral oils,
An aqueous solution containing an emulsifier, a rust inhibitor and a preservative as main components is further diluted with water, and copper, zinc, cobalt and nickel are dissolved therein.

The wire thus obtained was subjected to JIS
A rubber adhesion test was performed in accordance with the rubber adhesion test method specified in G3510 (1992). The die life was also evaluated in the same manner as described above. The rubber was vulcanized at about 145 ° C. for about 20 minutes.

[0026]

[Table 1]

From Table 1, it can be seen that the steel wire that has been wet drawn by the lubricant according to the present invention has excellent adhesion. Also, it can be seen that the wire drawing according to the present invention has a long die life and good wire drawing properties.

[0028]

According to the method of the present invention, excellent adhesion is imparted to a steel wire under high productivity and low cost. Therefore, when this steel wire is coated with rubber, it is indispensable on the rubber side. The adhesion promoter such as cobalt or nickel can be reduced or omitted.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a multi-step slip type wet wire drawing machine.

FIG. 2 is a diagram showing the relationship between zinc concentration and die life in wet drawing.

FIG. 3 is a diagram showing a relationship between copper concentration and die life in a wet intermediate line.

FIG. 4 is a diagram showing a relationship between a cobalt concentration and a die life in wet drawing.

FIG. 5 is a graph showing the relationship between the concentration of cobalt in a lubricant and the adhesiveness of a wire (rubber adhesion).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lubricant tank 2a, 2b Drive capstan 3 Drive capstan 4 Dice 5 Final die 6 Drive capstan

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 103/06 C10M 103/06 D 105/24 105/24 105/58 105/58 105/74 105/74 125/04 125/04 173/02 173/02 // C10N 10:02 C10N 10:02 10:04 10:04 10:16 10:16 40:32 40:32

Claims (4)

[Claims] 1. A steel wire characterized in that, in wet drawing a brass-plated steel wire, a wet lubricant containing zinc and further containing one or both of cobalt and nickel is used. Wire drawing method. 2. The wet lubricant according to claim 1, wherein the wet lubricant contains zinc: 0.30 g / l or more, and further contains one or both of cobalt and nickel in a total amount of 0.30 g.
/ 1 / l or more. 3. The wet lubricant according to claim 2, wherein the wet lubricant contains at least 0.35 g / l of zinc, and further contains one or both of cobalt and nickel in a total amount of 0.40 to 0.45 g / l.
A method for drawing a steel wire, wherein the composition has a composition containing 0.80 g / l. 4. A steel wire for reinforcing rubber articles obtained by the wire drawing method according to claim 1.