WO2013035805A1

WO2013035805A1 - Metal wire for rubber reinforcement, manufacturing method for same, and tyre

Info

Publication number: WO2013035805A1
Application number: PCT/JP2012/072785
Authority: WO
Inventors: 酒井　康夫; 松岡　映史; 山下　健一; 山田　孝幸; 児玉　順一; 福本　徹; 冬繆
Original assignee: 栃木住友電工株式会社; 住友電工スチールワイヤー株式会社; 新日本製鐵株式会社; 住友ゴム工業株式会社
Priority date: 2011-09-06
Filing date: 2012-09-06
Publication date: 2013-03-14
Also published as: IN2014CN02314A; CN103814159B; JP6137587B2; KR20140073518A; JP2013053359A; CN103814159A

Abstract

　One purpose of the present invention is to provide a metal wire for rubber reinforcement that exhibits excellent wire drawability and adhesion with rubber compositions.　The aforementioned issue is resolved by a metal wire for rubber reinforcement characterized by having a metal core wire, and a coating layer that covers the metal core wire and comprises Cu, Zn and Co, and by the composition of the surface layer of the coating layer from the surface to a depth of 15nm inwards in the radial direction being 60at% to less than 69at% of Cu and 0.5at%-5.0at% of Co.

Description

Rubber reinforcing metal wire, manufacturing method thereof and tire

The present invention relates to a rubber reinforcing metal wire for reinforcing a rubber composition, a method for producing the same, and a tire using the rubber reinforcing metal wire.

It is known to incorporate rubber reinforcing metal wires such as steel cords to reinforce rubber compositions such as tires, timing belts and hoses. This type of rubber reinforcing metal wire is provided with a coating layer that covers the metal wire in order to provide adhesion to the rubber composition to be reinforced. In addition, since the rubber reinforcing metal wire is subjected to wire drawing, it is common to form a brass plating layer as a coating layer in order to provide lubricity to the drawing die.

: Japanese Unexamined Patent Publication No. 2002-13081

As such a metal wire for reinforcing rubber, Patent Document 1 performs brass plating containing 15 to 45 atm% of Cu in order to achieve both the adhesion between the rubber composition and the workability of the metal wire for rubber reinforcement. In such a metal wire, it is proposed that 0.5 to 5.0 atm% of at least one of Co and Ni is contained in the surface layer from the surface of the brass plating to a depth of 15 nm inside the metal wire in the radial direction.

However, the present inventors have found that the metal wire described in Patent Document 1 still has room for improvement. In the metal wire described in Patent Document 1, attention is not paid to the amount of Cu in the surface layer, but the ratio of Cu, Co, Zn in the surface layer including the amount of Cu in the surface layer is the adhesive strength between the rubber composition and the rubber composition. And found to affect the workability. In particular, in the metal wire for rubber reinforcement described in Patent Document 1, there is a possibility that the Cu concentration in the surface layer may be low, and cracks are generated on the surface of the coating layer during the wire drawing process due to the low Cu content. It was considered that the yield of manufacturing metal wires for rubber reinforcement might be poor because it would cause a decrease in wire workability.

Therefore, an object of the present invention is to provide a rubber reinforcing metal wire excellent in wire drawing workability and adhesive strength and a method for producing the same.

In order to solve the above problems, the present invention provides the following.
(1) A core wire,
A coating layer containing Cu, Zn, Co covering the core wire,
The composition of the surface layer from the surface of the coating layer to a depth of 15 nm in the radial direction inside is Cu: 60 at% or more and less than 69 at%, Co: 0.5 at% or more and 5.0 at% or less Metal wire for reinforcement.
(2) The metal wire for reinforcing rubber according to (1), wherein the coating layer is brass containing 60 at% or more and 75 at% or less of Cu.
(3) The rubber according to (1) or (2), wherein the composition of the entire coating layer is Cu: 60 at% or more and 75 at% or less, Co: 1.0 at% or more and 7.0 at% or less. Metal wire for reinforcement.
(4) The rubber reinforcing metal wire according to any one of (1) to (3);
A tire having a rubber layer covering the metal wire for rubber reinforcement.
(5) A coating layer containing Cu at 60 at% to 75 at% is formed on the core wire,
In the core wire, the composition of the surface layer from the surface of the coating layer to the depth of 15 nm in the radial direction is Cu: 60 at% or more and less than 69 at%, Co: 0.5 at% or more and 5.0 at% or less. A method for producing a metal wire for rubber reinforcement, comprising performing a heat treatment for 5 seconds or more at a temperature of 500 ° C or higher and 650 ° C or lower.

The metal wire for reinforcing rubber according to the present invention has sufficient wire drawing workability because the surface layer of the coating layer which is liable to crack during wire drawing contains Cu having a ductility of 60 at% to 69 at%. In addition, since the surface layer of the coating layer serving as an interface with the rubber composition contains 0.5 to 5.0 at% of Co that improves adhesion to the rubber composition, the adhesion to the rubber composition is also excellent.

The rubber reinforcing metal wire in the present invention is used to reinforce rubber products such as tires and hoses. For example, a tire can be formed by covering a stranded wire cord formed by twisting a plurality of rubber reinforcing metal wires together with rubber.

This metal wire for reinforcing rubber is composed of a core wire made of steel wire or the like and a coating layer covering the core wire. As the core wire, a metal wire having a diameter of 0.1 mm to 0.7 mm can be preferably used.

The coating layer is provided to protect the metal core wire from the outside, and to improve the drawability of the rubber reinforcing metal wire and the adhesion to the rubber composition. The coating layer is formed of brass having high ductility and excellent workability. Moreover, in order to improve adhesiveness with rubber | gum, a coating layer is formed including Co. The thickness of the coating layer is preferably 0.1 μm or more and 0.5 μm or less.

</ RTI> Of the components contained in the coating layer, the more ductile Cu is contained, the more the wire can be drawn without causing cracks, so the workability is improved. On the other hand, when there is too much Cu, the adhesiveness with time falls with rubber | gum, and deterioration of rubber | gum tends to advance. In addition, as the amount of Co increases, the adhesiveness with time with the rubber composition is improved. However, when the amount is too large, the coating layer becomes hard and cracks are likely to occur during wire drawing, and wire drawing workability is greatly reduced. Therefore, the coating layer is preferably brass containing 60 at% or more and 75 at 5 or less of Cu.

For improving the workability and adhesion by the composition of the coating layer, particularly the Cu and Co ratio, the present inventors adhered when the Co component in the region having a depth of 15 nm in the radial direction from the surface of the coating layer was increased. It was confirmed that the performance was improved. Therefore, a region from the surface of the coating layer to a depth of 15 nm was defined as the surface layer, and it was studied to adjust the ratio of Cu and Co in the surface layer. In other words, pay attention only to the surface layer, not the entire coating layer of the metal wire for reinforcing rubber, and if the surface layer Cu is prone to crack during wire drawing, the workability is improved and it is also an interface with the rubber composition. It has been found that if the Co in the surface layer is increased, the drawability and adhesion of the metal wire for rubber reinforcement can be improved.

Specifically, when the composition of the surface layer of the coating layer is Cu: 60 at% or more and less than 69 at%, Co: 0.5 or more and 5.0 at% or less, the wire drawing workability is excellent and the adhesion to the rubber composition is achieved. It has been found that a metal wire for rubber reinforcement excellent in properties can be obtained.

<Specific example of manufacturing method>
A method for producing the rubber reinforcing metal wire as described above will be described.
First, the steel rod is stretched to a predetermined diameter, heat-treated and pickled to obtain a metal core wire. Next, Cu layer, Co layer, Zn layer, Cu layer, Zn layer, and Co layer are plated in this order to adhere to the surface of the metal core wire to form a coating layer, thereby obtaining a metal wire for rubber reinforcement.

Further, the obtained rubber reinforcing metal wire is heat-treated for 5 to 25 seconds in a thermostatic bath at 500 ° C. to 650 ° C., and sufficiently alloyed, so that the final coating layer surface is exposed in the radial direction. Cu, Co, and Zn are diffused in the coating layer so that the composition of the surface layer up to a depth of 15 nm is Cu: 60 to 69 at%, Co: 0.5 to 5.0 at%, and the balance is Zn and impurities. .

Regarding the temperature and time of the heat treatment, if the temperature is lower than 500 ° C., it takes time for alloying, and there is a variation in the movement of Cu to the surface layer. The wire drawability is greatly reduced. On the other hand, if the heat treatment temperature is higher than 650 ° C., the movement of Cu to the surface layer becomes too large, the Cu concentration of the surface layer becomes too high, and the adhesiveness over time may be lowered. Further, the surface Zn layer is melted or denatured to increase the surface layer impurities, thereby reducing the adhesiveness. Further, the surface layer portion of the metal core wire is denatured and the strength level is lowered, so that it is difficult to finally secure the necessary strength of the steel wire. In order to ensure such a problem, there is an appropriate heat treatment time according to the temperature, and this test is also conducted based on this.

<Example>
With respect to the rubber reinforcing metal wires as described above, Examples 1 to 27 and Comparative Examples 1 to 13 having a wire diameter of 0.90 mm were prepared and evaluated for wire drawing workability and adhesiveness.

The wire drawing workability was evaluated by a wire drawing test. In the wire drawing test, a rubber reinforcing metal wire that could be drawn to 0.23 mm was evaluated as ◯, and a rubber reinforcing metal wire that was broken and could not be drawn to 0.23 mm was evaluated as ×.

Moreover, adhesiveness was evaluated as follows. In other words, as described above, four metal wires drawn to 0.23 mm are prepared, and the four metal wires are twisted together to create a metal reinforcing wire for rubber reinforcement. It is sandwiched between rubber, vulcanized for 20 minutes at a temperature of about 150 ° C. and a pressure of 50 kg / cm ² , and further stored at a high temperature and high humidity of 80 ° C. and 95% humidity for 5 days. Then, rubber | gum was peeled from the metal strand for rubber reinforcement, and the adhesiveness of rubber was evaluated 10 steps from the state of the rubber adhering to the metal strand for rubber reinforcement. In this embodiment, a steel wire having a score of 7 or more was evaluated as a steel wire excellent in adhesiveness.

First, wire drawing workability and adhesiveness were evaluated for Examples 1 to 8 and Comparative Examples 1 to 6 having different Cu ratios in the composition of the surface layer of the coating layer. The results are shown in Table 1. In addition, the ratio of Cu can be changed by changing the average composition of the whole coating layer, or changing the heat treatment time and the heat treatment temperature.

As is apparent from Table 1, the steel wire of Examples 1 to 8 in which the ratio of Cu in the surface layer of the coating layer is 60 at% or more and less than 69 at% has good results of the core wire test, and the adhesiveness is also good. A good score of 7 and 8 was obtained. On the other hand, in Comparative Examples 1 to 5 in which the ratio of Cu in the surface layer of the coating layer is less than 60 at%, the amount of Cu is too small and the wire drawing workability is inferior. In No. 6, it was confirmed that the amount of Cu was too large and the adhesiveness over time was inferior.

Next, in Examples 9 to 17 and Comparative Examples 7 to 9 having different Co ratios in the composition of the surface layer of the coating layer, wire drawing workability and adhesiveness were evaluated in the same manner as described above. The results are shown in Table 2. Similar to the Cu ratio, the Co ratio can be changed by changing the average composition of the entire coating layer or by changing the heat treatment time or the heat treatment temperature.

As is apparent from Table 2, the steel wire of Examples 9 to 17 in which the Co ratio of the surface layer of the coating layer is 0.5 to 5 at% shows good results of the core wire test, and the adhesiveness is also good. A good score of 7 and 8 was obtained. On the other hand, in Comparative Example 7 in which the Co ratio of the surface layer of the coating layer is less than 0.5 at%, the amount of Co is too small and the adhesiveness of the rubber composition with time is inferior. In Comparative Examples 8 and 9 having more than%, it was confirmed that the amount of Co was too large and the wire drawing workability was inferior.

Next, the steel wire having a coating layer having a substantially constant average composition was evaluated for the change in the composition of the surface layer of the coating layer, the wire drawing workability, and the adhesiveness when the heat treatment time at 550 ° C. was changed. . The results are shown in Table 3.

As is clear from Table 3, in Comparative Example 10 in which the heat treatment time was 3 seconds, the Cu component did not sufficiently diffuse to the surface layer, and as a result, the Cu component in the surface layer was lower than 60 at% and the wire drawing workability was poor. On the other hand, in Examples 18 to 20 in which the heat treatment time was 5 seconds or more, it was confirmed that the Cu component was sufficiently diffused to the surface layer, and a steel wire with good wire drawing workability and adhesiveness could be obtained.

Next, regarding the steel wire having a coating layer having a substantially constant average composition, the change in the composition of the surface layer of the coating layer, the wire drawing workability and the adhesiveness when the heat treatment temperature of the heat treatment for 5 seconds is changed. Evaluation was performed in the same manner. The results are shown in Table 4.

As is apparent from Table 4, in Examples 21 to 27 in which the heat treatment temperature was 500 to 650 ° C., the Cu component was appropriately diffused to the surface layer, and the Cu component in the surface layer was 60 at% or more and less than 69 at%. Therefore, good results were obtained for both wire drawing workability and adhesiveness. On the other hand, in Comparative Examples 11 and 12 where the heat treatment temperature was less than 500 ° C., the Cu component was not sufficiently diffused to the surface layer, and the results of poor wire drawing workability were obtained. Further, in Comparative Example 13 where the heat treatment temperature was higher than 650 ° C., the Cu component was excessively diffused, and the Cu component was excessively present in the surface layer.

Further, as apparent from Tables 1 to 4, in addition to the composition of the surface layer of the coating layer, the composition of the entire coating layer is Cu: 60 at% or more and 75 at% or less, Co: 1.0 at% or more and less than 7.0 at% It was confirmed that a steel wire having good drawing workability and adhesiveness could be obtained.

As mentioned above, although this invention was demonstrated using the embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above-described embodiment. This application is based on Japanese Patent Application No. 2011-193887 filed on September 6, 2011, the contents of which are incorporated herein by reference.

Claims

Core wire,
A coating layer containing Cu, Zn, Co covering the core wire,
The composition of the surface layer from the surface of the coating layer to a depth of 15 nm in the radial direction inside is Cu: 60 at% or more and less than 69 at%, Co: 0.5 at% or more and 5.0 at% or less Metal wire for reinforcement.
The metal wire for reinforcing rubber according to claim 1, wherein the coating layer is made of brass containing 60 at% or more and 75 at% or less of Cu.
3. The rubber reinforcing metal wire according to claim 1, wherein the composition of the entire coating layer is Cu: 60 at% or more and 75 at% or less and Co: 1.0 at% or more and less than 7.0 at%.
A metal wire for rubber reinforcement according to any one of claims 1 to 3,
A tire having a rubber layer covering the metal wire for rubber reinforcement.
A coating layer containing 60 at% or more and 75 at% or less of Cu is formed on the core wire, and the composition of the surface layer from the surface of the coating layer to the depth of 15 nm in the radial direction is Cu: 60 at% or more and less than 69 at%, Co: A method for producing a metal wire for rubber reinforcement, characterized by subjecting the core wire to a heat treatment for 5 seconds or more at a temperature of 500 ° C. or more and 650 ° C. or less so as to be 0.5 at% or more and 5.0 at% or less.