JP2012172231A - Copper-zinc alloy plating method on steel wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-zinc alloy plating method on steel wire in which the plating process efficiency and the uniformity of a plated layer are superior, and the space saving is also superior.SOLUTION: In the copper-zinc alloy plating method on a steel wire, a copper-zinc alloy plated layer is formed on the steel wire w by passing the steel wire w in plating liquid in a plating tank 4. Plating liquid is allowed to flow in the direction opposite to the traveling direction of the steel wire w in the plating tank 4. A plurality of plating tanks 4 are preferably used, and the plating tanks 4 are preferably arranged in parallel to each other. A copper-zinc alloy anode is preferably used for an anode.

Description

  The present invention relates to a copper-zinc alloy plating method on a steel wire, and in particular, relates to a copper-zinc alloy plating method on a steel wire excellent in plating treatment efficiency and plating layer uniformity, and excellent in space saving.

  Since steel wires used for reinforcing rubber articles are embedded in rubber and used, adhesion to rubber is important. In order to improve the adhesion between the steel wire and rubber, the surface of the steel wire is usually plated with copper-zinc alloy. In a general copper-zinc alloy plating method, a copper plating layer and a zinc plating layer are electroplated in separate baths, respectively, and then heat-treated to thermally diffuse copper and zinc, thereby copper-zinc alloy plating. A layer is formed (for example, Patent Document 1).

  Such a sequential plating process has a disadvantage that the plating process efficiency is poor because it includes a copper plating layer forming process, a galvanized layer forming process, and a thermal diffusion process. In addition, since a work space is required for each process, there is a problem that the plating processing facility becomes large-scale.

  In order to solve such a problem, for example, Patent Document 2 contains a copper salt, a zinc salt, an alkali metal pyrophosphate, and at least one selected from amino acids or salts thereof. A plating tank having a salt concentration within a predetermined range has been proposed. According to this, since the copper-zinc alloy plating layer can be formed by a single plating process, the plating process efficiency is good and the plating equipment can be downsized. Further, it has been reported that if a plating bath described in Patent Document 2 is used, a uniform copper-zinc alloy plating layer can be formed with a wide current density. In addition, Patent Document 3 proposes an electrolysis cell for wire rod electroplating that enables electroplating operation with high current density and low electrolysis voltage.

Japanese Patent Laid-Open No. 07-11593 JP 2009-127097 A Japanese Patent Laid-Open No. 61-136698

  As described above, a copper-zinc alloy plating layer having a uniform composition can be obtained by using the plating tank described in Patent Document 2. However, even when such a plating solution is used, it is necessary to study the plating process conditions and the like for industrial use. Moreover, in the electrolysis cell for wire rod electroplating described in Patent Document 3, the uniformity of the plating layer has not been sufficiently studied.

  Then, the objective of this invention is providing the copper-zinc alloy plating method to the steel wire which was excellent in the plating process efficiency and the uniformity of the plating layer, and was excellent in the space-saving property.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by adopting the following configuration, and has completed the present invention.

That is, the copper-zinc alloy plating method to the steel wire of the present invention is a steel wire copper which forms a copper-zinc alloy plating layer on the steel wire by passing the steel wire through the plating solution in the plating tank. -In the zinc alloy plating method,
In the plating tank, a plating solution is allowed to flow in a direction opposite to the traveling direction of the steel wire.

  In the present invention, it is preferable that there are a plurality of plating tanks. In the present invention, the plating tanks are preferably arranged in parallel. Further, in the present invention, a copper-zinc alloy anode is provided. It is preferable to use it.

  ADVANTAGE OF THE INVENTION According to this invention, the copper-zinc alloy plating method of the steel wire which was excellent in the plating process efficiency and the uniformity of the plating layer, and excellent in the space-saving property can be provided.

It is a schematic explanatory drawing of one suitable embodiment of the copper-zinc alloy plating method to the steel wire of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic explanatory view of one preferred embodiment of a method for plating a copper-zinc alloy onto a steel wire of the present invention. As shown in the drawing, first, the steel wire w unwound from the unwinding device 1 is subjected to acid cleaning and water cleaning in the acid treatment device 2 and the water washing device 3a, respectively. Next, the steel wire w is guided into the plating tank 4, and a plating layer is formed on the surface of the steel wire w by electroplating. Thereafter, the steel wire w is washed with water by the water washing device 3 b, dried by the air knife 5, and taken up by the winding device 6. In the figure, 7 indicates a capstan, and 8 indicates a guide roll.

  In the present invention, a copper-zinc alloy plating solution is used as the plating solution. Therefore, since the copper plating layer formation process, the galvanization layer formation process, and the thermal diffusion process which have been conventionally performed can be omitted, the plating treatment efficiency can be improved. Moreover, since the copper-zinc alloy plating layer is formed at a time, the plating processing facility can be reduced in size.

  In the present invention, it is important that the flow of the plating solution in the plating tank 4 is in a direction opposite to the traveling direction of the steel wire (hereinafter referred to as “counterflow”). Here, the arrow in the plating tank 4 in FIG. 1 shows the flow direction of a plating solution. In general, in the plating process, the alloy composition in the plating layer also varies as the relative flow rate of the plating solution varies. Therefore, when a parallel flow (flow in the same direction as the traveling direction of the steel wire) and a counter flow are mixed in the plating tank, it is difficult to efficiently form a plating layer having a uniform composition. In the present invention, a plating layer having a uniform composition can be efficiently formed by flowing a counter flow of the plating solution to the steel wire.

  In the present invention, the means for generating the counter flow of the plating solution is not particularly limited, and various pumps and agitators can be used. The counter flow velocity is 5 to 50 m / min. It is preferable that The counter flow velocity is 5 m / min. If it is less than this, mixing of the parallel flow and the counter flow may not be sufficiently eliminated, which is not preferable. On the other hand, the flow velocity of the counter flow is 50 m / min. If it is larger, the flow of the plating solution in the plating tank is greatly disturbed, and it may be difficult to form a plating layer having a uniform composition.

  In the present invention, it is preferable to use a plurality of plating tanks. By arranging a plurality of plating tanks, the contact time between the steel wire and the plating solution can be increased, and the plating processing efficiency can be further improved. In this case, as shown in FIG. 1, it is preferable that the plating tanks 4 are arranged in parallel (two rows and six tanks in the illustrated example). By arranging the plating tanks 4 in parallel, the steel wire w can be reciprocated and the plating tank 4 can be passed through a plurality of times. Thereby, the plating treatment efficiency can be further improved. Moreover, when the plating tanks are arranged in series, the plating apparatus becomes large, but this problem can be solved by arranging the plating tanks in parallel.

  In the present invention, any anode can be used as long as it is used for copper-zinc alloy plating, but it is preferable to use a copper-zinc alloy anode. Thereby, the density | concentration of the copper ion and zinc ion in the plating tank 4 can be kept constant, and the uniformity of a plating layer can be improved. Further, it eliminates the trouble of replenishing the plating solution on a regular basis and is excellent in workability.

  The plating solution used in the present invention is not particularly limited, but contains a copper salt, a zinc salt, an alkali metal pyrophosphate, and at least one selected from amino acids or salts thereof, and has a pH of 10 to 12. The copper-zinc alloy plating solution which is can be used suitably.

  Any copper salt can be used as long as it is a known copper ion source for the plating solution. For example, copper pyrophosphate, copper sulfate, cupric chloride, copper sulfamate, cupric acetate, basic Examples include copper carbonate, cupric bromide, copper formate, copper hydroxide, cupric oxide, copper phosphate, copper fluorosilicate, copper stearate, cupric citrate, etc., one of these May be used alone, or two or more of them may be used.

  Any zinc salt may be used as long as it is known as a zinc ion source for a plating tank. For example, zinc pyrophosphate, zinc sulfate, zinc chloride, zinc sulfamate, zinc oxide, zinc acetate, zinc bromide , Basic zinc carbonate, zinc oxalate, zinc phosphate, zinc fluorosilicate, zinc stearate, zinc lactate, etc., and only one of these may be used, or two or more may be used. Also good.

  Any alkali metal pyrophosphate can be used as long as it is known, and examples thereof include a sodium salt and a potassium salt thereof.

  The pH of the plating solution is 10 to 12, preferably 10.5 to 11.8. When the pH is less than 10, it is difficult to obtain a plating layer having a uniform composition when the current density is high. On the other hand, when the pH exceeds 12, precipitates are formed, so that it is difficult to obtain a plating layer having a uniform composition. For pH adjustment, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide and alkaline earth metal hydroxides such as calcium hydroxide can be suitably used, and potassium hydroxide is preferred.

  Any known amino acid can be used, for example, glycine, alanine, glutamic acid, aspartic acid, threonine, serine, proline, tryptophan, histidine, etc. α-amino acid or its hydrochloride, sodium salt, etc. Among them, histidine is preferable. In addition, only 1 type may be used among these and 2 or more types may be used. These addition amounts are preferably 0.08 mol / L to 0.22 mol / L.

  In the present invention, the blending amount of each component of the plating solution is not particularly limited and can be appropriately selected. However, in consideration of industrial handling, the copper salt is 2 to 40 g / L in terms of copper, zinc salt. Is preferably 0.5 to 30 g / L in terms of zinc, 150 to 400 g / L pyrophosphate alkali metal salt, and about 0.2 to 50 g / L amino acid or salt thereof.

In the copper-zinc alloy plating method on the steel wire of the present invention, it is only important that the flow of the plating solution is opposite to the traveling direction of the steel wire. be able to. For example, the current density during the plating process can be 5 to 20 A / dm ² . Moreover, the temperature of a plating tank can be about 30-50 degreeC.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Example 1: Lab experiment>
A steel wire having a wire diameter of 1.5 mm was subjected to acid cleaning and water cleaning, and then a plating treatment was performed under the following conditions using a copper-zinc alloy plating solution having the following composition. Thereafter, it was washed with water and dried to obtain a steel wire with copper-zinc alloy plating. The flow rate of the counter flow during the plating process is 10 m / min. It was. About the obtained steel wire with copper-zinc alloy plating, the plating layer thickness was measured, and the plating layer thickness (μm / mm.) Formed per unit time was calculated and evaluated as the plating treatment efficiency. The obtained results are shown in Table 1.

<Copper-zinc alloy plating bath>
Copper sulfate 27g / L
Zinc sulfate 18g / L
Potassium pyrophosphate 350g / L
L-histidine 15g / L
pH 11.5
Cathode current density 18A / dm ²
Plating bath temperature 40 ℃

<Comparative example: Laboratory experiment>
The plating treatment efficiency was evaluated in the same procedure as in Example 1 except that no counter flow was applied. The obtained results are shown in Table 1.

  By flowing a counter flow during the plating treatment, a plated layer having a uniform composition was obtained for the steel wire of Example 1. Further, from Table 1, it was confirmed that the plating process efficiency was improved by flowing a counter flow during the plating process.

<Example 2: Actual machine test>
The plating treatment efficiency was evaluated using a plating apparatus having a plating bath of 6 tanks of the type shown in FIG. A steel wire having a wire diameter of 1.5 mm was subjected to acid washing with the acid treatment device 2 and water washing with the water washing device 3a. Plating treatment was performed with six plating layers 4. The composition of the plating solution was the same as that used in Example 1, and the wire speed of the steel wire in the plating layer 4 was 30 m / min. The number of times the plating bath was passed was set to (15 times). After the plating treatment, the steel wire was washed with a water washing device 3b and dried with an air knife 5 to obtain a steel wire with copper-zinc alloy plating. During the plating process, the counter flow velocity is 10 m / min. It was. About the obtained steel wire with copper-zinc alloy plating, the plating layer thickness was measured, and the plating layer thickness (μm / min.) Formed per unit time was calculated and evaluated as the plating treatment efficiency. The obtained results are shown in Table 1.

<Conventional example: Actual machine test>
A steel wire having a wire diameter of 1.5 mm was subjected to acid cleaning and water cleaning, and then subjected to plating treatment according to the following conditions using a copper sulfate plating bath and a zinc sulfate plating bath having the following composition. Thereafter, it was washed with water and dried to obtain a steel wire having a copper plating layer and a zinc plating layer. In the plating process, the wire speed of the steel wire in the plating tank is 30 m / min. It was. Subsequently, it was made to diffuse at 400 degreeC with an electric heating apparatus, and the steel wire with a copper-zinc alloy plating layer was obtained. With respect to the obtained steel wire with copper-zinc alloy plating, the plating treatment efficiency was calculated and evaluated by the same method as in Example 2. The obtained results are shown in Table 1.

<Copper pyrophosphate plating bath>
Copper pyrophosphate 65g / L
Pyrophosphate 12g / L
pH 9
Cathode current density 10 A / dm ²
Plating bath temperature 50 ℃

<Zinc sulfate plating bath>
Zinc sulfate 350g / L
Sulfuric acid 1g / L
pH 2
Cathode current density 30A / dm ²
Plating bath temperature 30 ° C

※：銅−亜鉛合金めっき装置の設備長を指数として表したものである。

*: The equipment length of the copper-zinc alloy plating equipment is expressed as an index.

  From Table 2, it can be seen that the plating method of the present invention is superior in plating treatment efficiency and space saving performance as compared with the conventional plating treatment. In addition, the composition of the plating layer of the steel wire obtained by Example 2 was uniform.

DESCRIPTION OF SYMBOLS 1 Unwinding apparatus 2 Acid treatment apparatus 3a, 3b Flushing apparatus 4 Plating tank 5 Air knife 6 Winding apparatus 7 Capstan 8 Guide roll

Claims (4)

In the method of copper-zinc alloy plating of steel wire, by forming a copper-zinc alloy plating layer on the steel wire by passing the steel wire through the plating solution in the plating tank,
A copper-zinc alloy plating method for a steel wire, wherein a plating solution is allowed to flow in a direction opposite to the traveling direction of the steel wire in the plating tank.   The copper-zinc alloy plating method to the steel wire according to claim 1, wherein the plating tank is plural.   The copper-zinc alloy plating method to the steel wire of Claim 2 with which the said plating tank is arrange | positioned in parallel.   The copper-zinc alloy plating method to the steel wire as described in any one of Claims 1-3 using a copper-zinc alloy anode.

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