KR20140073518A

KR20140073518A - Metal wire for rubber reinforcement, manufacturing method for same, and tyre

Info

Publication number: KR20140073518A
Application number: KR1020147008833A
Authority: KR
Inventors: 야스오 사카이; 아키후미 마츠오카; 켄이치 야마시타; 타카유키 야마다; 준이치 고다마; 토루 후쿠모토; 동 미아오
Original assignee: 토치기 스미토모 덴코 가부시키가이샤; 신닛테츠 스미킨 가부시키가이샤; 스미토모 고무 고교 가부시키가이샤; 스미토모 덴코 스틸 와이어 가부시키가이샤
Priority date: 2011-09-06
Filing date: 2012-09-06
Publication date: 2014-06-16
Also published as: WO2013035805A1; CN103814159A; CN103814159B; IN2014CN02314A; JP6137587B2; JP2013053359A

Abstract

One of the objects of the present invention is to provide a rubber reinforcement metal wire excellent in wire drawing processability and adhesion to a rubber composition. Wherein the composition of the surface layer from the surface of the coating layer to the depth of 15 nm in the radial direction on the surface of the coating layer is from 60 at% to less than 69 at% of Cu, Co: not less than 0.5 at% and not more than 5.0 at%. The above problems are solved by a metal wire for rubber reinforcement.

Description

TECHNICAL FIELD [0001] The present invention relates to a metal wire for rubber reinforcement, a method of manufacturing the same,

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

BACKGROUND OF THE INVENTION [0002] It is known to reinforce rubber reinforcing steel wires such as steel cords to reinforce rubber compositions such as tires, timing belts, and hoses. In this kind of rubber reinforcing metal wire, a coating layer covering the metal wire is formed to give an adhesive force to the rubber composition to be reinforced. In addition, since wire drawing is performed on the rubber reinforcement metal wire, a brass plating layer is generally formed as a coating layer in order to impart lubricity to the draw die.

Japanese Laid-Open Patent Publication No. 2002-13081

As such a rubber reinforcement metal wire, Patent Document 1 discloses a metal wire to which brass plating containing 15 to 45 atomic% of Cu is applied in order to achieve both an adhesion force with a rubber composition and a workability of a rubber reinforcement metal wire, It is proposed to contain 0.5 to 5.0 atm% of at least one of Co and Ni in the surface layer from the surface to the depth of 15 nm inward in the radial direction of the metal wire.

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, the amount of Cu in the surface layer is not taken into consideration, but the ratio of Cu, Co, and Zn in the surface layer, including the amount of Cu in the surface layer, I found that. Particularly, in the rubber reinforcement metal wire described in Patent Document 1, there is a possibility that the Cu concentration in the surface layer is low, cracks are generated on the surface of the coating layer during drawing processing due to low Cu content, The yield of the manufacturing of the reinforcing metal wire might be bad.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a metal wire for rubber reinforcement excellent in drawability 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,

And a coating layer containing Cu, Zn, and Co covering the core wire,

Wherein the composition of the surface layer up to a depth of 15 nm in the radial direction from the surface of the coating layer is from 60 at% to less than 69 at% of Cu and at least from 0.5 at% to 5.0 at% of Co.

(2) The metal wire for rubber reinforcement according to (1), wherein the coating layer is a brass containing 60 at% or more and 75 at% or less of Cu.

(3) The metal wire for rubber reinforcement according to (1) or (2), wherein the composition of the whole coating layer is from 60 at% to 75 at% of Cu and at least 1.0 at% to 7.0 at% of Co.

(4) A rubber-reinforcing metal wire according to any one of (1) to (3)

And a rubber layer covering the rubber reinforcement metal wire.

(5) A coating layer containing not less than 60 at% and not more than 75 at% of Cu in the core wire is formed,

Wherein the composition of the surface layer from the surface of the coating layer to the depth of 15 nm in the radial direction is set to be not less than 60 at% and less than 69 at%, and Co: not less than 0.5 at% and not more than 5.0 at% Wherein the heat treatment is performed for 5 seconds or more at a temperature equal to or lower than the melting point of the rubber.

According to the rubber reinforcement metal wire according to the present invention, the surface layer of the coating layer, which is susceptible to cracking during drawing, contains 60 at% or more and 69 at% or less of copper (Cu) rich in ductility. Also, since the surface layer of the coating layer which is an interface with the rubber composition contains 0.5 to 5.0 at% of Co for improving the adhesion with the rubber composition, the adhesion to the rubber composition is also excellent.

(Mode for carrying out the invention)

The rubber reinforcement metal wire in the present invention is used for reinforcing a rubber product such as a tire or a hose. For example, a rubber can be coated on a twisted wire cord formed by twisting a plurality of rubber reinforcement metal wires to form a tire.

The rubber reinforcement metal wire is composed of a core wire made of steel wire or the like and a coating layer covering the core wire. A metal wire having a diameter of 0.1 mm to 0.7 mm can be suitably used for the core wire.

The coating layer is formed to protect the metal core wire from the outside and further improve the drawing workability of the rubber reinforcement metal wire and the adhesion with the rubber composition. The coating layer is formed of brass having high ductility and excellent workability. Further, in order to improve the adhesion with rubber, the coating layer is formed to include Co. The thickness of the coating layer is preferably 0.1 mu m or more and 0.5 mu m or less.

As the Cu contained in the coating layer contains a large amount of Cu having high ductility, it is possible to produce a product without cracking, so that the workability is improved. On the other hand, if the amount of Cu is excessively large, the adhesion with time of the rubber deteriorates and the deterioration of the rubber tends to progress. The more Co is, the better the adhesion with the rubber composition with the lapse of time is improved. However, if it is too much, the coating layer becomes hard and cracks are easily generated during the drawing process, resulting in a drastically deteriorated drawing processability. Therefore, it is preferable that the coating layer is a brass containing Cu at 60 at% or more and 75 at% or less.

The present inventors have found that when the composition of the coating layer, particularly the improvement in workability and adhesion according to the Cu and Co ratios, is improved when the content of Co in the region of the depth of 15 nm in the radial direction on the surface of the coating layer is increased, Confirmed. Therefore, it was studied to define a region from the surface of the coating layer to a depth of 15 nm as a surface layer, and adjust the ratio of Cu to Co in the surface layer. That is, paying attention only to the surface layer rather than the entire coating layer of the rubber reinforcement metal wire, the workability is improved by increasing the amount of Cu in the surface layer which is liable to be cracked during the drawing process. If the amount of Co in the surface layer, It is possible to improve the drawability and adhesion of the metal wire for rubber reinforcement.

Specifically, when the composition of the surface layer of the coating layer is not less than 60 at% and less than 69 at% of Cu and not less than 5.0 at% of Co and not less than 0.5 at% of Co, the rubber reinforcement metal wire having excellent drawability and excellent adhesion with the rubber composition &Lt; / RTI >

A description will be given of a method for manufacturing a rubber reinforcement metal wire as described above.

First, the steel rod is stretched to a predetermined diameter, followed by heat treatment and acid pickling to obtain a metal core wire. Next, a Cu layer, a Co layer, a Zn layer, or a Cu layer, a Zn layer and a Co layer are plated in this order to adhere to the surface of the metal core wire to form a coating layer to obtain a rubber reinforcement metal wire.

The obtained rubber reinforcing metal wire was subjected to a heat treatment in a thermostatic chamber at 500 ° C to 650 ° C for 5 seconds to 25 seconds and sufficiently alloyed so that the composition of the surface layer from the surface of the final coat layer to the depth of 15 nm Cu: 60 to 69 at%, Co: 0.5 to 5.0 at%, Cu, Co, and Zn are diffused in the coating layer so that the remainder becomes impurities with Zn.

Regarding the temperature and the time of the heat treatment, if the temperature is lower than 500 ° C, alloying takes time, and there is a deviation in the movement of Cu to the surface layer, so that a portion having a low Cu concentration in the surface layer tends to come out. The drawability is greatly reduced. If the heat treatment temperature is higher than 650 占 폚, the migration of Cu to the surface layer becomes too large, and the Cu concentration in the surface layer becomes too high, and there is a fear that the adhesion with the lapse of time is lowered. Further, the Zn layer in the surface layer is melted or denatured, so that impurities in the surface layer are increased, and the adhesiveness is lowered accordingly. Further, the surface layer of the metal core wire is denatured and the strength level is lowered, which makes it difficult to secure the strength of the finally required steel wire. In order to secure such a problem, there is a proper heat treatment time corresponding to the temperature, and the present test is also carried out for the present test.

Examples 1 to 27 and Comparative Examples 1 to 13 each having a wire diameter of 0.90 mm were prepared for the above rubber reinforcing metal wires to evaluate the drawing workability and adhesion.

The fresh workability was evaluated by a freshness test. In the freshness test, the rubber reinforcing steel wire which could be drawn up to 0.23 mm was evaluated as?, And the rubber reinforcing steel wire which was broken and could not be drawn to 0.23 mm was evaluated as?.

The adhesiveness was evaluated as follows. That is, as described above, four fresh metal wires were prepared to 0.23 mm, and four metal wires were twisted to each other to form a twisted metal wire for rubber reinforcement. The twisted metal wire for rubber reinforcement was sandwiched with rubber, Deg.] C and a pressure of 50 kg / cm < 2 > for 20 minutes, and further stored at a temperature of 80 deg. C and a humidity of 95% for 5 days in a high temperature and high humidity condition. Thereafter, the rubber was peeled from the metal twisted wire for rubber reinforcement, and the adhesion of the rubber was evaluated in ten steps from the rubber condition attached to the twisted metal wire for rubber reinforcement. In the present embodiment, the steel wire having a rating of 7 or more was evaluated with a steel wire having excellent adhesion.

First, in Examples 1 to 8 and Comparative Examples 1 to 6 in which the proportion of Cu differs from the composition of the surface layer of the coating layer, the drawing processability and adhesion were evaluated. The results are shown in Table 1. The ratio of Cu can be changed by changing the average composition of the entire coating layer or by varying the heat treatment time or the heat treatment temperature.

As is apparent from Table 1, in the steel wires of Examples 1 to 8 in which the proportion of Cu in the surface layer of the coating layer was 60 at% or more and less than 69 at%, the results of the core wire test were good and the adhesion was evaluated as 7 and 8 Good results were obtained. On the other hand, in Comparative Examples 1 to 5, in which the proportion of Cu in the surface layer of the coating layer was less than 60 at%, the amount of Cu was too small and the drawing processability was poor. In Comparative Example 6 in which the ratio of Cu in the surface layer of the coating layer was 69 at% It was confirmed that the adhesiveness was deteriorated with time.

Next, in Examples 9 to 17 and Comparative Examples 7 to 9 in which the ratio of Co was different from that of the surface layer of the coating layer, the drafting workability and adhesion were evaluated in the same manner as described above. The results are shown in Table 2. The ratio of Co can be changed by changing the average composition of the entire coating layer or varying the heat treatment time or the heat treatment temperature in the same manner as the ratio of Cu.

As is evident from Table 2, the steel wires of Examples 9 to 17, in which the proportion of Co in the surface layer of the coating layer was 0.5 to 5 at%, showed good results of the core wire test, Results were obtained. On the other hand, in Comparative Example 7 in which the proportion of Co in the surface layer of the coating layer was less than 0.5 at%, the amount of Co was excessively small and the adhesion of the rubber composition over time deteriorated, and the ratio of Co in the surface layer of the coating layer was more than 5 at% In Examples 8 and 9, it was confirmed that the amount of Co was excessively large and the drawability was poor.

Next, the change in the composition of the surface layer of the coating layer, the drawing processability and the adhesiveness were evaluated with respect to the steel wire having the coating layer of substantially constant average composition when the heat treatment time at 550 캜 was changed. The results are shown in Table 3.

As is apparent from Table 3, in Comparative Example 10 in which the heat treatment time was 3 seconds, the Cu component was not sufficiently diffused to the surface layer, and as a result, the Cu component of the surface layer was lower than 60 at% and the drawability 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 the steel wire having both excellent drawing workability and adhesion was obtained.

Next, changes in the composition of the surface layer of the coating layer, drawing processability and adhesion were evaluated in the same manner as described above when the heat treatment temperature of the heat treatment for 5 seconds was changed for the steel wire having the coating layer of substantially constant average composition . The results are shown in Table 4.

As apparent from Table 4, in Examples 21 to 27 wherein the heat treatment temperature was set to 500 to 650 캜, since the Cu component was appropriately diffused to the surface layer and the Cu component in the surface layer was less than 60 at% and less than 69 at% And good adhesion were obtained. On the other hand, in Comparative Examples 11 and 12 in which the heat treatment temperature was lower than 500 占 폚, the Cu component did not sufficiently spread to the surface layer, resulting in poor drawability. In Comparative Example 13 in which the heat treatment temperature was higher than 650 占 폚, it was confirmed that the Cu component was excessively diffused and the Cu component was excessively present in the surface layer, resulting in poor adhesion over time.

As is clear from Tables 1 to 4, if the composition of the entire coating layer is in the range of 60 at% to 75 at% of Cu and less than 7.0 at% of Co in addition to the surface layer of the coating layer, It was confirmed that a good steel wire was obtained.

While the present invention has been described with reference to the embodiment thereof, the technical scope of the present invention is not limited to the range described in the above embodiment. It is apparent to those skilled in the art that various changes or improvements can be added to the above embodiments. This application is based on Japanese Patent Application No. 2011-193887 filed on September 6, 2011, the content of which is incorporated herein by reference.

Claims

A core wire,
And a coating layer containing Cu, Zn, and Co covering the core wire,
Wherein the composition of the surface layer up to a depth of 15 nm in the radial direction from the surface of the coating layer is from 60 at% to less than 69 at% of Cu and at least from 0.5 at% to 5.0 at% of Co.

The method according to claim 1,
Wherein the coating layer is a brass containing 60 at% or more and 75 at% or less of Cu.

3. The method according to claim 1 or 2,
Wherein a total composition of the coating layer is from 60 at% to 75 at% of Cu and at least from 1.0 at% to less than 7.0 at% of Co.

The rubber reinforcing metal wire according to any one of claims 1 to 3,
And a rubber layer covering the rubber reinforcement metal wire.

Wherein a coating layer containing Cu in an amount of not less than 60 at% and not more than 75 at% is formed on the core wire and the composition of the surface layer in the radial direction from the surface of the coating layer to a depth of 15 nm is not less than 60 at% % Or more and 5.0 at% or less, and the heat treatment is performed on the core wire at a temperature of 500 DEG C or more and 650 DEG C or less for 5 seconds or more.