JPH01263286A - Rust remover for copper - Google Patents

Abstract

PURPOSE:To effectively remove rust from copper and to effectively prevent reoxidation with a rust remover contg. a component such as 2- aminoethylmercaptan by adding a component such as acrylamide to the rust remover. CONSTITUTION:One or more kinds of components (A) selected among 2- aminoethylmercaptan, thioglycolic acid and salts of them are used in combination with one or more kinds of components (B) selected among acrylamide, acrylic acid, acrylate and homo- or copolymers of these monomers. An oxide film on the surface of copper is removed by the chelating effect of the components A and the components B are adsorbed on the rust-free surface. The resulting adsorbed film improves the washability and can effectively prevent reoxidation.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention relates to copper and copper alloys (hereinafter referred to as copper metals).
Regarding rust remover for use.

SUMMARY OF THE INVENTION This invention provides a method for preparing 1-aminoethyl mercaptan selected from the group consisting of 2-aminoethyl mercaptan, thioglycolic acid, and salts thereof.
A rust remover for copper metal frames containing one or more components as active ingredients, one or more selected from the group consisting of acrylamide, acrylic acid, acrylates, and homopolymers or copolymers of these monomers. By blending the above components, it is possible to effectively remove rust from copper metals and prevent re-oxidation without post-treatment using an inhibitor after rust removal.

Conventional technology Mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid, or 2-aminoethyl mercaptan and its salts have been used as rust removers for heat exchanger pipes, printed circuit boards, lead frames for electronic parts, etc. made of copper metals. Chelating agents such as (see JP-A-61-250186) or thioglycolic acid and its salts (see British Patent No. 807172, Japanese Patent Publication No. 40-16771) are used, but the following There is a problem like this.

Mineral acids are particularly corrosive to copper metals, so they are unsuitable for removing rust from treated objects with different degrees of oxidation or from products requiring high precision.

On the other hand, the above chelating agents not only have excellent oxide film removal properties, but also have low corrosivity to metals, are mostly odorless, and have excellent workability, as well as post-treatments such as washing with water and drying. If the rust removal treatment is insufficient, the rust-removal treated surface may be re-oxidized and discolored. For this reason, there is no dispute that post-treatment using a solvent such as alcohol or an inhibitor such as hensitriasol is performed after rust removal.

The present invention solves the problems associated with rust removal treatment using a chelating agent as described above, and removes copper metals without post-treatment using organic solvents or inhibitors after rust removal. This was done to provide a rust remover that can effectively prevent rust and re-oxidation.

That is, the present invention provides one or more components selected from the group consisting of 2-aminoethyl mercaptan, thioglycolic acid, and salts thereof, and acrylamide,
The present invention relates to a rust remover for copper metals containing one or more components selected from the group consisting of acrylic acid, acrylates, and homopolymers or copolymers of these monomers.

One or more components selected from the group consisting of 2-aminoethyl mercaptan, thioglycolic acid, and salts thereof (hereinafter referred to as component 1) have traditionally been used as active ingredients in rust removers for copper metals. You can use whatever is available as appropriate.

Examples of the salt of 2-aminoethyl mercaptan include hydrochloride,
In addition to salts of free acids such as sulfates and phosphates, acetates, lactates, P-toluenesulfonates, alkylsulfonates,
Examples include salts of organic acids such as benzoates, and examples of salts of thioglycolic acid include ammonium salts, sodium salts, potassium salts, and the like.

Particularly suitable as component I for use in the present invention are 2-aminoethylmercaptan hydrochloride and thioglycolic acid ammonium salt.

The amount of component I is usually at least 0.5% by weight, and if it is less than this, it will be difficult to achieve the intended purpose of the invention.

A feature of the present invention is that one or more components selected from the group consisting of acrylamide, acrylic acid, acrylic acid salts, and homopolymers or copolymers of these monomers (hereinafter referred to as component It is to be used in combination with component I.

Examples of acrylates include sodium salts, potassium salts, and ammonium salts.

Examples of homopolymers or copolymers of acrylamide, acrylic acid and acrylates include polymers represented by the following formula: where Rit CON H,
, C0OH, COONa.

C00K or COON I (represents a group such as 4, n is 1
The number is from 10,000 to 150,000, preferably from 20,000 to 70,000.

The amount of component H blended is not particularly limited, but is usually about 10
The intended purpose of the present invention can be fully achieved at an amount of at least 100 ppm, preferably about 100 to 500 ppm. However, it may be used at a higher concentration depending on the type of object to be treated and the state of rust.

Water is normally used as the solvent for the rust remover of the present invention, but water-soluble organic solvents such as methanol, ethanol, isopropyl alcohol, etc. may be used in combination as appropriate to improve washability (warm resistance) after rust removal. Good too.

If desired, the rust remover of the present invention may contain conventional additives such as organic acids such as tartaric acid, citric acid, and oxalic acid in order to increase the rust removing ability.

Copper metals treated with the above-mentioned rust preventive agent may be washed with water and then naturally dried, but depending on the working process, they may be forcedly dried using a drying means and/or an organic solvent.

The mechanism of action of the above rust remover according to the present invention is not limited to any particular theory, but is believed to be as follows. That is, after the oxide film on the surface of copper metals is removed by the chelating effect of component I, component (2) is adsorbed onto the surface of the rust-removed metal.
It is believed that this blue-absorbing film, together with improving the washability (formability) in water washing treatment, effectively prevents re-oxidation.

Hereinafter, the present invention will be explained by examples.

Examples 1 to 8 The rust removal effects of rust removers 1 to 8 prepared according to the formulations shown in Table 1 were investigated by the following rust removal test.

Rust removal test I Copper plate (CI 100P: 50mmX25mmX 1.o
mm) on an experimental hot plate and rotate it at approximately 150°.
C. for 5 minutes in air to form a brown oxide film on the surface.

Add 1 of the above copper plates to 100 IC of each of rust removers 1 to 4 at room temperature.
After being immersed for a minute, the copper plate was taken out, washed with 20M tap water, and air-dried for 24 hours. The discoloration state of the surface of the copper plate was evaluated according to the JAS K2513 copper plate corrosion classification table. The evaluation results are shown in Table-1.

Rust removal test■ Brass plate (C3560P; 50++unX25mmX1
．． omm) on a laboratory hot plate and heat it for about 15 minutes.
It was heated in air at 0'C for 20 minutes to form an oxide film on the surface.

Each of Rust Removers 5 to 8 was 100. ! (The above brass plate was immersed in the solution for 1 minute at room temperature, then taken out, washed with 200 mQ of tap water, and air-dried for 24 hours.) - The state of discoloration on the surface of the brass plate was determined according to the JIS K2513 copper plate corrosion classification table. The evaluation results are shown in Table 1.

Comparative Examples 1 to 12 Rust removers 1' to 12'' prepared according to the formulation shown in Table 1
The rust removal effect was investigated based on Examples 1 to 8.

In this case, rust removal test I was conducted for rust removers 1' to 6'', and rust removal test H was conducted for rust removers 7' to 12''.

The V'P flTli results are shown in Table-1.

(Hereinafter, blank space) Effects of the Invention By using the rust remover according to the present invention, only the oxide film on the surface of copper metals can be removed and reoxidized without the need for post-treatment using an inhibitor after rust removal. Prevention can be carried out effectively.

Claims (1)

[Claims] One or more components selected from the group consisting of 1,2-aminoethylmercaptan, thioglycolic acid and salts thereof, and acrylamide, acrylic acid, acrylates and monomers thereof. A rust remover for copper metals containing one or more components selected from the group consisting of homopolymers and copolymers. 2. A method for removing rust from copper metals, which comprises treating an object made of copper metals with the rust remover according to claim 1, washing with water, and drying.