JP2005246447A - Method for drawing steel wire for reinforcing rubber product, and steel wire and steel cord for reinforcing rubber product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for drawing a steel wire for reinforcing a rubber product, which can restrain deterioration of vulcanized rubber and drop in the durability of the rubber product such as a tire and attain high adhesiveness, and the steel wire and steel cord for reinforcing the rubber product. <P>SOLUTION: In the invented wet type wire drawing method, the brass-plated steel wire 1 is drawn by means of a slip type multistage wire drawing machine 10 equipped with a die 14, and driving capstans 13A and 13B which draw the steel wire 1 passing through the die 14, with wet lubricant 11. The wet lubricant 11 contains a metal benzoate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for drawing a steel wire for reinforcing a rubber article used for a steel cord used for reinforcement in various rubber articles such as tires and conveyor belts, and a steel wire for reinforcing a rubber article and a rubber article reinforcement obtained thereby. Steel cord (hereinafter, also simply referred to as “drawing method”, “steel wire”, and “steel cord”, respectively).

  Steel cords for reinforcing rubber articles used for reinforcing rubber articles such as tires are usually obtained by drawing brass-plated wire (steel wire) to a desired wire diameter to obtain steel filaments. Manufactured by twisting together as appropriate. This wire drawing process is generally performed using a multi-stage slip type wet wire drawing machine 10 as shown in FIG.

  In the illustrated apparatus 10, two multistage drive capstans 13A and 13B are disposed in a lubricating liquid tank 12 filled with a wet lubricant 11 so as to oppose each other, and these drive capstans 13A and 13B are arranged. In the process of alternately passing the steel wires 1 to the respective stages via the dies 14, the steel wires 1 are drawn by the dies 14 at each stage. The drawn steel wire 1 is sent to the winding process from the drive capstan 15 disposed outside the lubricating liquid layer 12 through the final die 16.

  When wet drawing of steel wire is performed using such a multi-stage slip type wet wire drawing machine 10 and wet lubricant 11, conventionally, a zinc complex of a phosphate ester or the like has been used as an extreme pressure coating. A technique has been used in which friction between a die and a wire is reduced to suppress damage to the die and the wire. This has played a very important role in producing steel wires and thus steel cords with high productivity.

As an improved technique related to the wet drawing process of steel wire subjected to such brass plating, for example, by using a wet lubricant containing zinc and one or both of cobalt and nickel, high productivity is achieved. And a steel wire drawing method that balances low cost and excellent initial adhesion of the wire (described in Patent Document 1), and a wet lubricant containing one or both of cobalt and nickel. There has been proposed a steel wire drawing method (described in Patent Document 2) that achieves the same effect by passing through a drawing path in which the slip speed in the drive capstan is prescribed.
JP 2002-11519 A (Claims etc.) JP 2002-11520 A (Claims etc.)

  On the other hand, the adhesion between the brass-plated steel wire and the rubber is obtained by the reaction of copper in the plating and sulfur in the rubber. However, if the above-mentioned extreme pressure coating remains on the wire surface, this extreme pressure coating inhibits the copper-sulfur reaction, which causes deterioration of the vulcanized rubber and adhesion between the rubber and the wire. There was a problem that the durability deteriorated when applied to rubber products such as tires.

  Accordingly, an object of the present invention is to provide a steel for reinforcing rubber articles that can achieve high adhesion by solving the above-mentioned problems and suppressing deterioration of vulcanized rubber and durability of rubber products such as tires. An object of the present invention is to provide a wire drawing method, a steel wire for reinforcing rubber articles, and a steel cord for reinforcing rubber articles obtained thereby.

  As a result of intensive studies, the present inventor has found that high adhesiveness between the rubber and the wire can be obtained by including a specific additive in the wet lubricant used for wet wire drawing. It came to complete.

  That is, the method of drawing a steel wire for reinforcing rubber articles according to the present invention comprises a slip-type multi-stage system comprising a steel wire subjected to brass plating, a die, and a drive capstan that pulls out the steel wire that has passed through the die. In wet drawing using a wire drawing machine and a wet lubricant, a metal salt of benzoic acid is contained in the wet lubricant.

  In the wire drawing method of the present invention, it is preferable that the concentration of the benzoic acid metal salt in the wet lubricant is 0.05 to 0.5 g / l.

  The steel wire for reinforcing rubber articles of the present invention is characterized by being drawn by the above drawing method.

  Furthermore, the steel cord for reinforcing rubber articles of the present invention is characterized in that a plurality of filaments of the steel wires for reinforcing rubber articles are twisted together.

  According to the wire drawing method of the present invention, a steel wire for reinforcing rubber articles having good adhesiveness to rubber, and consequently a steel cord for reinforcing rubber articles, can be obtained by the above configuration. Therefore, by applying the steel cord for reinforcing rubber articles to a rubber product such as a tire, it is possible to suppress the deterioration of the vulcanized rubber and improve the durability adhesion of the rubber product.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The present invention relates to a steel wire that has been subjected to brass plating, wet-stretching using a slip-type multistage wire drawing machine including a die and a drive capstan that pulls out the steel wire that has passed through the die, and a wet lubricant. This is a technique related to improvement of the wire drawing process, and is characterized in that a wet lubricant containing a metal salt of benzoate is used in the wet wire drawing process.

  That is, in the present invention, by performing wet wire drawing using a wet lubricant containing a benzoic acid metal salt, a strong benzoic acid metal salt derivative film can be formed on the surface of the steel wire. In addition, a steel wire for reinforcing rubber articles with improved rubber-wire adhesion can be obtained. Therefore, by applying the steel cord for reinforcing rubber articles using the steel wire, it is possible to obtain various rubber articles having excellent durability, such as tires.

  The type of benzoic acid metal salt is not particularly limited, and various types can be used, but a metal salt of Zn or Co is particularly preferable. In the present invention, the antiseptic effect of the wet lubricant can also be obtained as an accompanying effect of including the metal benzoate in the wet lubricant.

  FIG. 2 shows the relationship between the benzoic acid metal salt concentration in such a wet lubricant and the durable adhesiveness (rubber coverage). As can be seen from this figure, the adhesiveness depends on the benzoic acid metal salt concentration. In the present invention, the benzoic acid metal salt concentration in the wet lubricant is preferably 0.05 to 0.5 g / l. Within range. By making the benzoic acid metal salt concentration 0.05 g / l or more, the effect of improving the durable adhesiveness can be obtained satisfactorily. The effect of improving the adhesion cannot be obtained.

  FIG. 3 shows the relationship between the vulcanization time and the durable adhesiveness (rubber coverage) when the benzoic acid metal salt concentration in the wet lubricant is changed. This figure also shows that the adhesiveness depends on the metal benzoate salt concentration. That is, when the benzoic acid metal salt concentration is 0.05 g / l or more, particularly 0.1 g / l or more, the rubber coverage in a short vulcanization time is increased, and the durable adhesion is improved. On the other hand, even when the benzoic acid metal salt concentration exceeds 0.5 g / l, no further improvement in adhesion is observed. Therefore, 0.05 g / l or more of a benzoic acid metal salt is preferably contained in the wet lubricant, and the upper limit is preferably 0.5 g / l from the viewpoint of cost reduction.

  The rubber coverage according to FIGS. 2 and 3 is obtained by conducting a rubber adhesion test in accordance with a rubber adhesion test method defined in JIS G3510 (1992).

  The wet lubricant used in the present invention is required to contain at least a metal salt of benzoic acid, but the other components can be the same as those used in ordinary wet lubricants and are particularly limited. is not. In particular, it is preferable to contain copper and zinc in addition to usual wet lubricant components such as oil agents, extreme pressure additives and surfactants. By containing zinc, it is possible to suppress the wear of the wire drawing die that affects the wire drawability and to achieve uniform wear.

  In the present invention, it is only necessary to satisfy the above conditions for the wet lubricant, and other conditions relating to the wire drawing process, such as wire speed, slip speed in a slip type multi-stage wire drawing machine, die shape, etc. Is not particularly limited. Moreover, the wire drawing method of the present invention is not particularly limited as long as the steel wire is drawn by wet drawing, and may be either single wire drawing or continuous wire drawing.

  Further, the steel cord for reinforcing rubber articles of the present invention may be any steel wire filament obtained by the above wire drawing method, as long as it is twisted by a plurality of wires, thereby having excellent adhesion to rubber. There is no particular limitation on the twisted structure.

Hereinafter, the present invention will be described specifically by way of examples.
Examples 1 to 5, Comparative Example About high carbon steel wire having a diameter of about 5.5 mm containing about 0.82% by weight of carbon, after repeatedly dry-drawing until the diameter is about 1.4 mm, About the wire prepared by adding the patenting treatment and the brass plating treatment, the diameter is about 0.00 mm using the multistage slip type wet wire drawing machine 10 shown in FIG. 1 and the wet lubricant 11 containing a benzoic acid metal salt. Wet drawing was performed until the thickness became 20 mm. At this time, the steel cord for reinforcing rubber articles of Examples 1 to 5 was obtained by changing the content of the metal benzoate in the wet lubricant 11 in wet wire drawing as shown in Table 1 below.

  The durable adhesion of the obtained steel wires of each Example was evaluated as a rubber coverage (%) in accordance with a rubber adhesion test method according to JIS G3510 (1992). The rubber vulcanization conditions at this time were 145 ° C. for 20 minutes.

  In addition, as a comparative example, a steel wire drawn using a wet lubricant 11 containing no benzoic acid metal salt was prepared, and the durability adhesion was evaluated in the same manner as in the above example. These results are shown in Table 1 below. As for the wet lubricant 11, an aqueous solution mainly composed of fatty acid, phosphoric acid, phosphoric ester, amines, mineral oil, emulsifier, rust preventive and preservative is further diluted with water, and then copper and zinc are added thereto. And about the Example, what mixed the benzoic acid metal salt was used.

  Table 1 shows the concentration of benzoic acid metal salt in the wet lubricant 11 and the durable adhesion (rubber coverage) when the steel wire is vulcanized at about 145 ° C. for about 20 minutes for the steel wires of Examples and Comparative Examples. ). As shown in the table, in the steel cords of Examples 1 to 5 in which the benzoic acid metal salt was contained in the wet lubricant 11, with the increase in the content of the benzoic acid metal salt, the durability adhesion (rubber coverage) ) Was confirmed to improve.

It is a schematic diagram which shows a slip type multistage wire drawing machine. It is a graph which shows the relationship between the benzoic acid metal salt density | concentration in a wet lubricant, and durable adhesiveness (rubber coverage). It is a graph which shows the relationship between vulcanization time at the time of changing the benzoic acid metal salt density | concentration in a wet lubricant, and durable adhesiveness (rubber coverage).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel wire 10 Multistage slip type wet wire drawing machine 11 Wet lubricant 12 Lubricating liquid tank 13A, 13B Drive capstan 14 Die 15 Drive capstan 16 Final die

Claims (4)

  In carrying out wet drawing of a steel wire subjected to brass plating using a slip type multi-stage wire drawing machine including a die and a driving capstan that pulls out the steel wire that has passed through the die, and a wet lubricant A method of drawing a steel wire for reinforcing rubber articles, characterized in that a metal salt of benzoic acid is contained in the wet lubricant.   The method of drawing a steel wire for reinforcing rubber articles according to claim 1, wherein the metal salt of benzoate in the wet lubricant has a concentration of 0.05 to 0.5 g / l.   A steel wire for reinforcing rubber articles, which is drawn by the drawing method according to claim 1 or 2.   A steel cord for reinforcing rubber articles, comprising a plurality of filaments of the steel wire for reinforcing rubber articles according to claim 3 twisted together.

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