JPH0413431B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" This invention relates to a method for dissolving and peeling a tin or tin-lead alloy layer on the surface of a copper or copper alloy material. Alternatively, it is suitable for a method of dissolving and peeling off the tin or tin-lead alloy layer from the scrap of the copper alloy material to regenerate and recover copper and the copper alloy material from the scrap. ``Prior Art'' and ``Problems'' As is well known, copper or copper alloy materials having a tin or tin-lead alloy layer are plated in advance and machined such as press working, or parts. Some are plated after aging, others are soldered after being molded into products, and are widely used in the fields of electrical parts and electronic materials. By the way, the scrap generated during the processing process of products using copper or copper alloy materials and the scrap of products that have reached the end of their service life contain tin or tin alloys.
Contains about 0.1 to 5wt%. This scrap with tin or tin alloy still fused has very limited uses, so the tin or tin-lead alloy layer is removed and the copper or copper alloy material is recycled and recovered to expand its uses. There is a need. On the other hand, in the conventional method for dissolving and peeling off the tin layer on the surface of copper and copper alloy materials, the following acidic copper salt method has been proposed. A feature of this acidic copper salt method is that it has the great advantage of almost no erosion and dissolution of the base material. However, this acidic copper salt method can only dissolve and peel off the tin layer alone, and is particularly ineffective when it comes to dissolving and peeling off tin-lead alloy layers.Furthermore, even in the process of dissolving and peeling only the tin layer, it is often difficult to remove the tin layer. This method cannot be put to practical use because non-uniform melting occurs and the speed of dissolution and peeling is affected. Therefore, conventionally, the scraps have to be recycled by returning them to the raw material stage, which poses a major problem in terms of recycling efficiency. This invention improves the above-mentioned problems and makes it possible to dissolve and remove not only tin but also tin-lead alloy layers, uniformize and speed up the dissolution state, and minimize dissolution erosion of the base material. The object of the present invention is to provide a method for dissolving and peeling off a tin or tin alloy layer on the surface of a copper or copper alloy material. "Means for Solving the Problems" The stripping solution used in the dissolution stripping method of the present invention is a material containing 0.5 to 10 wt% of copper ions and nascent oxygen.
It is an aqueous solution consisting of 0.1 to 15 wt% and 5 to 30 wt% of one or more acids selected from sulfuric acid, nitric acid, and hydrochloric acid. Hydrogen peroxide is a substance that has the above developmental period.
0.1 to 5 wt% and its stabilizer (for example, hydrogen peroxide stabilizer manufactured by Santoku Chemical Co., Ltd.; polyethylene glycol/cabrolactam compound) 1 to 10 wt%
or potassium permanganate 0.1-2wt
% is preferred. "Effect" The above stripping solution is based on the acid copper salt method, and by adding a small amount of a substance containing nascent oxygen to it, it can dissolve and strip not only tin alone but also tin-lead alloy layers. and even more uniform solubility,
It is possible to improve speed and to minimize dissolution and erosion of the base material. In the above configuration, the copper ion concentration is 0.5~10wt
%, preferably in the range of 1 to 5 wt%. This is because the copper ion concentration is 0.5wt%.
If it is less than 10wt%, the effect of replacing copper ions with tin and lead ions will be reduced, and uniform dissolution and peeling cannot be expected.On the other hand, if it exceeds 10wt%, no further improvement in the effect can be expected. It is. Further, the hydrogen peroxide concentration is preferably used in a range of 0.1 to 5 wt%, preferably 1 to 3 wt%. This is because if the hydrogen peroxide concentration is less than 0.1wt%, the tin-lead alloy layer will not be able to be dissolved and peeled off, and the tin layer will not have uniform solubility.On the other hand, if it exceeds 5%, the base material This is because the dissolution and erosion of the base material becomes severe and the loss of the base material becomes large. Furthermore, the concentration of hydrogen peroxide stabilizer is between 1 and
10wt% is appropriate and is proportional to the concentration of hydrogen peroxide, and the ratio to hydrogen peroxide is stabilizer/hydrogen peroxide =
A range of 1 to 10 is preferred. This is because if this ratio is less than 1, the effect cannot be expected and the decomposition of hydrogen peroxide is severe and unstable, whereas if the ratio exceeds 10, the decomposition of hydrogen peroxide is suppressed and its This is because it inhibits work. Furthermore, the concentration of potassium permanganate, which is a substance containing nascent oxygen used instead of hydrogen peroxide + stabilizer, is 0.1 to 2 wt%, preferably 0.1 to 2 wt%.
It is best to use it in a concentration range of 1wt%. This is because if the potassium permanganate concentration is less than 0.1wt%, the tin-lead alloy layer will not be able to be peeled off and will not have uniform solubility; on the other hand, if it exceeds 2wt%, it will cause dissolution and erosion of the base material. This is because it becomes more intense. In addition, the acid concentration of sulfuric acid, nitric acid, hydrochloric acid alone, or a mixture thereof is 5 to 30 wt%, preferably
It is best to use it in a concentration range of 10 to 25 wt%. This is because if the acid concentration is less than 5wt%, the effect cannot be expected, the dissolution and peeling time becomes extremely long, and uniform solubility is lost; conversely, if the acid concentration exceeds 30wt% This is because the dissolution effect cannot be expected to be improved any further than before, and it is uneconomical, and the environment and workability are deteriorated due to an increase in the amount of gas generated. Therefore, according to the method of the present invention in which the scrap is immersed in a stripping solution having the above-mentioned properties, the tin or tin-lead alloy layer on the surface can be easily removed by reducing the dissolution erosion of the base copper or copper alloy material. It can be peeled off quickly, and the scrap material can be recycled and recovered efficiently. Next, the present invention will be explained in more detail with reference to Examples. "Example" () Material to be treated (sample) (a) Dimensions: Thickness: 0.5 mm x Width: 50 mm x Length: 100 mm (b) Material: (a) C1201 (phosphorus deoxidized copper) (b) C2680 (brass) (c) C5212 (phosphor bronze) (d) C7351 (nickel silver) (c) Tin or tin-lead alloy layer (by electroplating) (1) Tin plating film thickness...1.0μm (2) Tin-lead A sample was prepared with an alloy plating thickness of 5.0 μm. () Judgment of the peeling state was carried out by visual inspection in the following four stages. (a) 99% or more dissolution and peeling……◎ (b) 95% or more dissolution and peeling……○ (c) 50% or more dissolution and peeling……△ (d) Less than 50% dissolution and peeling……× () The state of base material erosion was visually determined in the following four stages. (a) No erosion......◎ (b) Slight erosion......○ (c) Erosion......△ (d) Significant erosion......× Example 1 Stripper composition (1) Copper ion... 30g Hydrogen peroxide...10g Stabilizer (manufactured by Santoku Chemical Co., Ltd.)...50g Sulfuric acid...100g Water...Add until the total amount is 1.Immerse the sample in () above in the above dissolving and stripping solution at room temperature. The state of peeling of the plating layer and the state of erosion of the base material were determined. The results are shown in Table 1.

[Table] Example 2 Stripping solution composition (1) Copper ion...80g Potassium permanganate...10g Nitric acid...200g Water...Add until the total amount becomes 1 Dissolve and strip the sample in () above at room temperature. The peeling state of the plating layer and the erosion state of the base material were determined by immersing it in a liquid. The results are shown in Table 2.

[Table] Example 3 Stripper composition (1) Copper ion...50g Hydrogen peroxide...30g Stabilizer (manufactured by Santoku Chemical Co., Ltd.)...90g Sulfuric acid...100g Hydrochloric acid...100g Water...Total amount The sample in () above was immersed in the dissolving and removing solution at room temperature, and the peeling state of the plating layer and the erosion state of the base material were determined. The results are shown in Table 3.

【table】

[Table] Examples 4 to 9 Each of the materials shown in Table 4 below was immersed in the corresponding stripping solution shown in Table 4, and the peeling state of the plating layer and the erosion state of the base material were determined. The results are shown in Table 4.
It was shown to. For each of the above examples, the materials shown in Table 5 below,
Comparative examples were conducted using different stripping solution compositions. The results are shown in Table 5.

【table】

【table】

[Table] As is clear from the above, in the comparative example,
While there is no method that simultaneously satisfies peeling of the plating layer and minimal erosion of the base material, in the examples, the plating layer can be peeled off with almost no erosion of the base material. The time required for peeling is also short. "Effects of the Invention" As explained above, according to the method of the present invention, not only tin but also the tin-lead alloy layer can be dissolved and removed, and the melting state can be made uniform and faster. Moreover, dissolution erosion of the copper or copper alloy material that is the base material can be suppressed to a small amount.

Claims (1)

[Claims] 1. 0.5 to 10 wt% of copper ions, 0.1 to 15 wt% of a substance containing nascent oxygen, and 5 to 10 wt% of an acid consisting of one or more selected from sulfuric acid, nitric acid, and hydrochloric acid.
A copper or copper alloy material having a tin or tin-lead alloy layer on the surface is immersed in a dissolving and stripping aqueous solution containing 30 wt% to dissolve the tin or tin-lead alloy layer on the surface of the copper or copper alloy material. A method for dissolving and peeling a tin or tin-alloy layer on a surface of a copper or copper alloy material, the method comprising peeling off the tin or tin-alloy layer on the surface of a copper or copper alloy material. 2 The nascent oxygen-containing substance is hydrogen peroxide 0.1
5 wt% and 1 to 10 wt% of a hydrogen peroxide stabilizer, the method for dissolving and peeling off a tin or tin-lead alloy layer on a surface of a copper or copper alloy material according to claim 1. 3. The tin or tin-lead alloy layer on the surface of the copper or copper alloy material according to claim 1, wherein the substance containing oxygen in the nascent stage is 0.1 to 2 wt% potassium permanganate. Dissolution and peeling method.