KR20000042611A - Method for producing steel wire cord reinforcing tire - Google Patents

Abstract

PURPOSE: A method is provided to produce a steel wire cord for reinforcing a tire increasing abrasion resistance and rubber attachment without an additional thermal diffusing process. CONSTITUTION: A zincked steel wire(2) moves to a wire draw bench(4) filled with wet lubricating oil through a guiding roller(3). The steel wire is drawn from a supplying reel(1). The steel wire from the wire draw bench is guided to a winding reel(8) through two drawing capstans(7a,7b). A final die(9) is installed on a passage between two capstans and a cobalt compound tank(10) is installed on a passage right before passing through two capstans. Thus, the surface of the steel wire is contacted with solid or liquid cobalt compound and the cobalt coated steel wire passes through the final die. The cobalt elements are combined with zinc on the steel wire surface and alloyed with zinc on the surface.

Description

Manufacturing method of steel wire cord for tire reinforcement

The present invention relates to a steel wire cord used as a reinforcing material of a tire, and more particularly, to a liquid in one or two dies from a final die in a drawing process in which a galvanized layer is formed on the surface of the steel wire and thinly drawn through a multi-stage die. Or tire reinforcing steel wire that improves the corrosion resistance and water resistance of steel wire cord by alloying zinc and cobalt at the extreme surface layer of galvanized layer at high temperature and high pressure generated in fresh wire by using lubricant containing solid cobalt compound. It's about code.

In general, a steel tire cord used for reinforcing a tire of a vehicle has a brass (Cu / Sn) plated layer formed on its surface in order to improve adhesiveness with tire rubber and improve workability during steel wire manufacturing. The formed steel wire is embedded in tire rubber as a single body, or several strands of brass plated steel wire are manufactured in the form of a twisted cord and used in tire rubber.

The adhesion of rubber to brass-coated steel wire is known to depend on the bond between copper and brass in the brass. When such a brass-coated rubber reinforcing steel wire is present in the rubber molding during curing, the bonding force between the rubber and the steel wire is gradually maximized by chemical reaction of the brass alloy with the rubber at the contact portion of the two materials.

Copper contained in the brass alloy coated on the surface of the steel wire is known to act as an accelerator for the adhesion reaction during the curing period of the rubber molding, but in order to obtain high adhesion between the steel wire and the rubber, Since the speed must be properly controlled, the steel wire is covered with brass containing zinc in an appropriate proportion of copper as a means of slowing down the speed of the adhesion reaction.

The brass alloy layer coated on the reinforcing steel wire of rubber products, such as tires, to improve adhesion with rubber is generally composed of 60 to 70% copper and 30 to 40% zinc.

On the other hand, the adhesion between the brass-plated steel wire and the tire rubber gradually decreases over time compared to the initial stage of vulcanization, due to various factors.The main factor that causes the weakening of the adhesive force is applied to the tire while driving the vehicle. Loss of extreme heat and humidity.

That is, during high-speed driving of the vehicle, the temperature of the tire is increased, moisture is penetrated into the tire rubber by the damage of the tire rubber, and the surroundings of the wire cord are exposed to the chemical decomposition and corrosive atmosphere. Can be placed under extreme heat and moisture conditions, where the initial bond between the steel cord and the tire rubber will drop rapidly over time.

Therefore, in order to extend the service life of the tire reinforced by the steel wire cord, it is important to have high heat and water resistance as well as to maintain a high initial adhesive force between the steel wire cord and the tire rubber.

On the other hand, the heat resistance and water resistance of the steel wire cord may be improved by lowering the composition ratio of copper in the brass plating layer. In this respect, British Patent No. 1,205,419 proposes to reduce the copper content in the brass plating layer to 60% or less. Is being presented.

However, the brass alloy with such low copper content is mainly composed of β-brass due to the low copper content. Since such beta-brass has extremely poor workability due to its crystal structure, the freshness of the copper alloy as a subsequent process to the plated wire is excellent. There is a problem that is difficult to put to practical use because it falls.

In view of the above problems exhibited in the improvement of the heat and water resistance through the change of the composition of the brass alloy, by adding a third element to the brass to form a plating layer consisting of three-membered alloy to improve the corrosion resistance and water resistance The following conventional method which aims at is known.

That is, FR-2,198,830, GB-1,122,528, US-2,912,355, and Korean Patent Publication No. 82-631 disclose a method of obtaining a plated layer made of Cu-Zn-Co ternary alloy by adding cobalt after brass plating. In addition, EP-188,036 and US-4,226,918 disclose a method of plating nickel after brass plating.

However, in order to plate cobalt or nickel as a third element in addition to the copper and zinc plating layers as described above, there is a problem in that the complexity of the manufacturing process and the increase in manufacturing cost are inevitable.

Next, Korean Patent Publications No. 90-13046 and Korean Patent Publication No. 94-283 describe organic materials containing a third element instead of a method of plating a third element on the surface of brass plating, for example, hydrocarbon-based. A method of applying a plating layer made of ternary alloy to the surface of the steel wire by applying an oil containing nickel stearate or cobalt stearate to the mineral oil in the stranded wire of the steel wire cord and applying an oil coating of the brass plated steel wire cord.

However, even in the ternary alloy of copper-zinc-cobalt (or nickel) prepared by coating and alloying an organic material containing the third element, brass itself acts as a cathode to the steel wire in a low pH atmosphere and thus doubled. It has been pointed out that the formation of the electrode promotes corrosion, and it is difficult to suppress the phenomenon of corrosion due to the promotion of de-zinc phenomenon of brass in a high pH atmosphere.

On the other hand, as a way to solve the above disadvantages of the brass itself has been conducted a lot of research on a new plating method that does not use copper at all, and as a specific example, Korean Patent Publication No. 95-32717 After plating, the surface of the cobalt is plated again to form a zinc-cobalt alloy plating layer by a thermal diffusion method to improve the corrosion resistance and rubber adhesion of the steel wire cord.

However, in the method of forming the zinc-cobalt alloy plating layer, the steel wire itself is exposed to a high temperature atmosphere during the thermal diffusion process, and thus, the thermal effect is caused, resulting in a decrease in tensile strength of the steel wire, and thermal diffusion equipment and a lot of energy for thermal diffusion. It also has the disadvantage of requiring a higher manufacturing cost.

Accordingly, the present invention is to solve the disadvantages and problems that are pointed out in the conventional method for forming a plating layer to improve the rubber adhesiveness on the surface of the conventional steel wire, the surface of the steel wire during the drawing process of galvanized steel wire Cobalt compounds are applied and the coated cobalt compounds undergo a final drawing process to allow zinc and cobalt to be alloyed at the extreme surface layer of the galvanized layer, thereby requiring a cobalt plating process or a separate thermal diffusion process for alloying zinc and cobalt. It is an object of the present invention to provide a method for producing a steel wire cord for reinforcing tires to improve corrosion resistance and rubber adhesiveness, particularly water resistance.

1 and 2 is a schematic view of the tire reinforcing steel wire cord manufacturing apparatus of the present invention,

1 is a front view,

2 is a plan view.

((Description of the code for the main part of the drawing))

1. feeding reel 2. galvanized steel wire

3. Information roller 4. Freshness

5. Capstan 6a, 6b. die

7a, 7b. Withdrawal capstan 8. Winding reel

9. Final die 10. Cobalt compound bath

The object of the present invention is to apply a cobalt compound to the surface of the steel wire just before one or two dies from the final die in the drawing process of thinly galvanized steel wire through a continuous die to form a die immediately before the final die or the die. The cobalt component is combined with zinc by the high temperature and high pressure generated in the process of drawing as it passes through, thereby achieving a series of processes in which zinc and cobalt are alloyed at the pole surface layer of the galvanized layer.

1 and 2 is a schematic structural diagram of a tire reinforcing steel wire cord manufacturing apparatus of the present invention based on the steel wire cord manufacturing process of the present invention as follows.

First, the galvanized steel wire 2 drawn out from the supply reel 1 is moved to the drawing machine 4 filled with the wet lubricating oil through the guide roller 3.

In the drawing machine 4, a capstan 5 composed of a pair of multi-stage concentric structures is installed, and the steel wire 2 introduced into the drawing machine 4 passes through each end of the capstan 5 sequentially. It moves out of (4). At this time, the steel wire (2) is gradually from the original diameter in the process of passing through the plurality of die (6a) installed on the path passing through each end of the capstan (5) and the die (6b) mounted on the exit side of the drawing machine (4) Freshness is achieved with a decrease in phosphorus diameter.

Next, the steel wire (2) exiting the drawing machine (4) is guided to the two take-out capstan (7a) (7b) and finally to the winding reel (8), wherein between both capstan (7a) (7b) As the final die 9 is installed on the steel wire passing path of the cobalt compound bath 10 on the steel wire passing path immediately before, the surface of the steel wire 2 is in contact with the solid or liquid cobalt compound. The steel wire coated with the cobalt compound is a zinc-cobalt alloy on the extreme surface of the galvanized layer because the cobalt component in the cobalt compound is combined with zinc on the surface of the steel wire by the high temperature and high pressure generated in the process of passing through the final die (9). Becomes

1 and 2 illustrate an example in which a cobalt compound is brought into contact with the surface of the steel wire 2 immediately before the final die 9, but the contact of the cobalt compound immediately before the die before the final die 9 is different. A specific example of the cobalt compound may include a form in which the hexanedithiolate cobalt compound is sufficiently mixed with an organic solvent.

Details of the technical configuration of the present invention tire reinforcing steel wire cord manufacturing method and the specific plating layer formation process and characteristics, etc. will be clearly understood through the following examples.

First, in drawing a steel wire of diameter 1.40 mm coated with zinc so that the diameter is 0.22 mm by a continuous die, the hexanedithiolate cobalt compound immediately before the last die as shown in FIGS. 1 and 2 as described above. The mixture was uniformly mixed with a conventional organic solvent so as to contact the steel wire surface before passing the final die.

At this time, the cobalt component is combined with zinc by the steel wire passing through the final die in the state where the cobalt compound is in contact with the fresh lubricating oil and the high temperature and high pressure generated during the drawing, so that zinc-cobalt is alloyed.

The steel wires 0.22mm in diameter were twisted together in a twisted pair machine to produce steel wire cords having a 3 + 9x0.22 structure to measure corrosion resistance and rubber adhesion.

Adhesion test was carried out according to ASTM D-2229, wherein the vulcanization conditions were heated at 130 ° C. for 30 minutes at 60 atm to obtain an adhesive composite between the steel wire cord and the rubber.

The rubber adhesive composite thus obtained was stored for 3 weeks in an atmosphere of 96% relative humidity at 70 ° C., and then the adhesive strength (water resistance) was evaluated, and another adhesive composite was stored for 3 weeks in a 20% NaCl aqueous solution. Was evaluated.

For comparison with the Example specimen of the present invention, Comparative Example Specimen 1 and Zinc-Cobalt Alloy Coated with the three-way copper-clad-cobalt-plated layer coated by the conventional method were prepared by Comparative Example Specimen 2 Prepared and measured the water resistance and corrosion resistance of the same as in the above Example specimens.

The results of the measurement of adhesion to the inventive specimens and the comparative specimens are shown in Table 1 below.

division Alloying method Cobalt Composition Ratio (wt%) Water resistance Corrosion Adhesion Example ″ Zinc + Cobalt ″ alloying in the drawing process after galvanizing 0.15 100% 100% Comparative Example 1 ″ Copper + Zinc + Cobalt ″ alloy plating 3.50 75% 63% Comparative Example 2 ″ Zinc + Cobalt ″ alloy plating 0.80 95% 98%

In Table 1, the evaluation of the water resistance and corrosion resistance is 100%, and the comparative example is a result represented by a relative value.

As shown in Table 1, it can be seen that the steel wire cord produced by the method of the present invention is significantly improved in the water-resistant adhesive and corrosion-resistant adhesion compared to the wire cord produced by the conventional method.

As described above, the tire reinforcing steel wire produced by the method of the present invention is the final subsequent to the automatic application of the cobalt compound without the need for a separate plating process or a separate thermal diffusion process on the surface of the galvanized steel wire The zinc-cobalt alloy plated layer is obtained from the surface of the zinc plated layer by alloying zinc and cobalt in the drawing process, thereby simplifying manufacturing facilities and processes compared to the conventional method for forming a steel wire cord plated layer. The effect of improving the adhesiveness and corrosion resistance is expected.

Claims (1)

In the drawing process of thinly galvanizing steel wire through a plurality of dies, the high temperature generated when passing the cobalt compound-coated steel wire through the surface of the steel wire is coated with cobalt compound immediately before the final die or the die before. , Cobalt component is combined with zinc by high pressure to the alloy surface of the zinc-cobalt in the pole surface layer of the galvanized layer, characterized in that the manufacturing method of the steel wire cord for tire reinforcement.