JPH0564718B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an additive for an acid solution for pickling, and more particularly, to an additive for suppressing the dissolution of metal in an acid solution for pickling. This invention relates to an additive for pickling acid solutions that removes scale and rust of metal salts or metal oxides generated on the surface of metals in the solution, but suppresses dissolution of the metals themselves. The pickling acid solution additive of the present invention can be used as an additive for pickling acid solution for surface treatment of metal products, and the pickling acid solution additive of the present invention can be used as an additive for pickling acid solution for surface treatment of metal products. The pickling acid solution can be used for cleaning metal surfaces in metal surface treatments such as painting, enameling, plating, phosphating, or cold rolling treatments of metal products or their materials. [Technical Background and Description of Prior Art] In metal surface treatment, polishing and shaping of the metal surface using chemical dissolution of the metal using a chemical solution has long been known as chemical polishing of the metal surface. It is known that the surface of metals such as aluminum, iron, copper, zinc, or cadmium can be cleaned by immersing them in a chemical solution whose basic bath components are phosphoric acid, nitric acid, chromic acid, hydrochloric acid, hydrofluoric acid, or sulfuric acid. It is being (“Chemistry Handbook” published by Maruzen Co., Ltd.
(Page 1150 ~ "Metal Surface Treatment") In these metal surface treatments, the acid in the chemical solution dissolves and removes scale and rust on the metal surface, but it also dissolves the metal on the cleaned surface and This not only erodes and dissolves the metal surface, but also shortens the service life of the chemical solution due to an increase in the concentration of metal salts generated by dissolving the metal. This erosion of the metal surface,
It is known to add additives to drug solutions to inhibit dissolution. In surface treatment of iron or steel with hydrochloric acid, alkylamine, benzylquinolinium, alkylbenzylquinolinium halide, n-alkyltrimethylammonium, n-
- belongs to nitrogen-containing compounds such as alkylpyridinium, n-alkylquinolinium, hexamethylenetetramine (urotropin), hydroxyacetylene, propargyl alcohol, propargyl ether, propargyl thioether, mercaptan, sulfonium compounds, sulfoxide, thiocyanate, thiourea and thiazole The addition of compounds has been proposed to inhibit the erosion and dissolution of iron and steel, and some of these inhibitors have been shown to be effective in inhibiting the erosion and dissolution of aluminum, its alloys, nickel, titanium, and its alloys. It is also known that there are inhibitors that are effective in inhibiting the dissolution and erosion of metals by sulfuric, nitric, hydrofluoric, and phosphoric acids. [G. Schmidt: Report prepared for the European Conference of the Erosion Working Group on Inhibitors
European Federation of Corrosion Working
Party on Inhibitor), Application of Inhibtor for Acid
Media)] In addition, quaternary ammonium compounds are added to the pickling acid solution to remove scale and rust from metal surfaces.
Alternatively, organic nitrogen compounds other than ammonium compounds and quaternary ammonium compounds are added, thereby improving the descaling effect, corrosion inhibiting effect, and hydrogen embrittlement inhibiting effect, and also reducing the turbidity of the pickling solution.
It has been proposed to suppress the formation of sediments, oily substances and foaming in waste acid treatment. (Japanese Unexamined Patent Publication No. 61-37988) In research on pickling in the surface treatment of metal products, the present inventors found that the effect of dodecyltrimethylammonium chloride in suppressing dissolution of iron in hydrochloric acid was improved by the addition of polyvinyl alcohol. We have also found that the rust-removing effect of dodecyltrimethylammonium chloride is improved by adding hexamethylenetetramine, aniline, and triethanolamine, and based on these findings, we have arrived at the present invention. [Objective of the Invention and Summary of the Invention] An object of the present invention is to provide an additive that suppresses the dissolution of metal in an acid solution for pickling. An object of the present invention is to provide an additive in an acid solution for pickling that removes scale and rust of generated metal salts or metal oxides, but suppresses dissolution of the metal itself. Another object of the present invention is a pickling acid solution that can remove scale and rust on the metal surface in metal surface treatment, but can clean the metal surface without eroding or dissolving the metal itself. Our goal is to provide the following. The present invention provides an acid comprising (a) dodecyltrimethylammonium chloride, and (b) selected from the group consisting of polyvinyl alcohol, diethylene glycol, hexamethylenetetramine, aniline, triethanolamine, and mixtures thereof. This is an additive for acid solutions used in washing. The acid solution additive for pickling of the present invention inhibits metal dissolution and corrosion, but those containing hexamethylenetetramine (urotropin, hexamine), aniline or triethanolamine reduce the rust removal effect of metals. melting of metals, without
Erosion can be suppressed. The additive for pickling acid solutions of the present invention can be used as an additive for acid solutions normally used for pickling in metal surface treatment, such as hydrochloric acid, sulfuric acid, phosphoric acid, and hydrofluoric acid. When used with mixed acid solutions such as hydrochloric acid and phosphoric acid, and sulfuric acid and phosphoric acid, it improves the rust removal and scale removal effects, suppresses metal dissolution and erosion in metal surface treatment, and provides a clean and clean surface. It is possible to create a textured surface. [Detailed Description of the Invention] In the acid solution additive for pickling of the present invention, 2,000 to 20,000 parts by weight of polyvinyl alcohol is blended with 100 parts by weight of dodecyltrimethylammonium chloride. Dodecyltrimethylammonium chloride and polyvinyl alcohol are
Although it can be blended in any form of powder or aqueous solution, it is preferable to blend it in the form of an aqueous solution. By blending dodecyltrimethylammonium chloride and polyvinyl alcohol in the form of an aqueous solution, there is an advantage that a good state of dissolution can be maintained when added to the acid solution for pickling. When diethylene glycol is added to the acid solution additive for pickling comprising dodecyltrimethylammonium chloride and polyvinyl alcohol of the present invention, 2000 to 20000 parts by weight of polyvinyl alcohol and 2000 to 20000 parts by weight per 100 parts by weight of dodecyltrimethylammonium chloride are used. Parts by weight of diethylene glycol are blended, but these are preferably blended in the form of an aqueous solution in order to maintain a good dissolution state when added to the acid solution for pickling. In the acid solution additive for pickling comprising dodecyltrimethylammonium chloride and hexamethylenetetramine (urotropin, hexamine) of the present invention, 100 to 500 parts by weight of hexamethylenetetramine is blended to 100 parts by weight of dodecyltrimethylammonium chloride. However, similar to the above, these materials are mixed in the form of an aqueous solution,
Thereby, it is preferable to maintain a good dissolution state when added to an acid solution for pickling. Dodecyltrimethylammonium chloride, polyvinyl alcohol, diethylene glycol, hexamethylenetetramine, aniline, and triethanolamine in the acid solution additive for pickling of the present invention can also be blended by adding their respective aqueous solutions to the acid solution for pickling. . The acid solution additive for pickling of the present invention can be added to hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid or other acid solutions commonly used for pickling. It can also be added to a mixed acid solution of sulfuric acid and phosphoric acid. When the acid solution additive for pickling of the present invention is added to these mixed acid solutions, it is possible to promote the removal of scale and rust on the metal surface during pickling and to form a metal surface with a clean finish. The additive for acid solution for pickling of the present invention is 0.005 to 0.2 parts by weight (preferably 0.01 to 0.1 parts by weight) of dodecyltrimethylammonium chloride per 100 parts by weight of acid solution.
It is added to the pickling acid solution in an amount equal to (parts by weight). Next, the present invention will be explained in more detail using test examples that can be substituted for examples. Test Example 1 A test was conducted to examine the effects of the addition of polyvinyl alcohol and diethylene glycol on the effect of dodecyltrimethylammonium chloride on inhibiting the dissolution of iron by hydrochloric acid. (1) Preparation of test solution Add 0.5 ml of 0.5% dodecyltrimethylammonium chloride to 20.0 ml of 4M hydrochloric acid, and add 2% polyvinyl alcohol (degree of polymerization: 500) aqueous solution and 2% diethylene glycol in the amounts shown in Table 1. A test solution was prepared by adding the aqueous solution and then adding water to make a total volume of 40.0 ml. (2) Test method Accurately weigh the iron piece (10mm x 10mm x 1mm),
This iron piece was immersed in the test solution, and 2
After standing for a period of time, the iron piece was removed from the test solution and thoroughly washed with water. After air drying, the weight of the iron piece was accurately weighed, and the amount of iron piece dissolved by the test solution (mg/cm ² ) was calculated from the weight loss during immersion. (3) Test results The results were as shown in Table 1.

[Table] (4) Discussion The inhibitory effect of dodecyltrimethylammonium chloride on the dissolution of iron by hydrochloric acid is increased by the addition of polyvinyl alcohol or diethylene glycol, and is further increased by the addition of both polyvinyl alcohol and diethylene glycol. Test Example 2 The effect of addition of polyvinyl alcohol on the effect of dodecyltrimethylammonium chloride on inhibiting dissolution of iron by hydrochloric acid was tested in a system in which phosphoric acid coexisted. (1) Preparation of test solution (1-1) Test solution (control) A test solution (control) was prepared by adding 20.0 ml of water to 20.0 ml of 4M hydrochloric acid. (1-2) Test solutions 1 to 6 0.5 ml of 0.5% dodecyltrimethylammonium chloride aqueous solution was added to 20.0 ml of 6M hydrochloric acid, and the amount of phosphoric acid (1:
2) and a 2% aqueous solution of polyvinyl alcohol (degree of polymerization: 500), and further water was added to make the total volume 40.0 ml to prepare a test solution. (2) Test method Iron piece with red rust on its surface (10mm x 10mm x
1 mm) was accurately weighed, the iron piece was immersed in the test solution, and after being left at room temperature for 2 hours, the iron piece was taken out from the test solution and thoroughly washed with water. After air drying, the weight of the iron piece was accurately weighed, and the amount of red rust removed by the test solution and the amount of iron piece dissolved (mg/cm ² ) were calculated from the weight loss during immersion. (3) Test results The results were as shown in Table 2.

[Table] (4) Findings and discussion In either case, the red rust was completely removed;
Its surface was clean and warm. The effect of suppressing the dissolution of iron in hydrochloric acid by the coexistence of dodecyltrimethylammonium chloride and polyvinyl alcohol does not change even if phosphoric acid coexists. Test Example 3 A test was conducted to determine the effect of the addition of hexamethylenetetramine on the effect of dodecyltrimethylammonium chloride on inhibiting the dissolution of iron by hydrochloric acid. (1) Preparation of test solution (1-1) Test solution (control) A test solution (control) was prepared by adding 20.0 ml of water to 20.0 ml of 4M hydrochloric acid. (1-2) Test solution 1 (DTMA) Test solution 1 was prepared by adding 1.0 ml of 0.5% dodecyltrimethylammonium chloride aqueous solution and 19.0 ml of water to 20.0 ml of 4M hydrochloric acid. (1-3) Test solution 2 (HEXA) Test solution 2 was prepared by adding 1.0 ml of 1% hexamethylenetetramine aqueous solution and 19.0 ml of water to 20.0 ml of 4M hydrochloric acid. (1-4) Test solutions 3 to 6 (DTMA-HEXA) Add 0.5 of the amount shown in Table 3 to 20.0 ml of 4M hydrochloric acid.
% dodecyltrimethylammonium chloride aqueous solution and 1% hexamethylenetetramine aqueous solution, and then add water to make up the total amount.
Test solutions 3 to 6 were prepared by adjusting the volume to 40.0 ml. (2) Test method Accurately weigh a rusted iron piece (10 mm x 10 mm x 1 mm), immerse the iron piece in the test solution, leave it at room temperature for 5 hours, then remove the iron piece from the test solution and thoroughly test the iron piece. Washed with water. After air drying, the weight of the iron pieces was accurately weighed, and the amount of iron pieces dissolved (mg/cm ² ) was calculated from the weight loss during immersion. (3) Test results The results were as shown in Table 3.

[Table] Umu chloride
HEXA: Hexamethylenetetramine
(4) Findings and discussion The iron piece immersed in test solution 1 (DTMA) had a part of the oxide film on its surface remaining undissolved, but the iron piece immersed in test solution 2 (DTMA-HEXA) had a clean surface. It was warm on the surface. Adding dodecyltrimethylammonium chloride to hydrochloric acid suppresses the dissolution and erosion of iron, but also the dissolution of the oxide film. On the other hand, when hexamethylenetetramine (urotropin, hexamine) is added to hydrochloric acid to which dodecyltrimethylammonium chloride has been added, the dissolution of iron is suppressed without suppressing the dissolution of the oxide film. Test Example 4 A test was conducted on the effect of addition of aniline or triethanolamine on the effect of dodecyltrimethylammonium chloride on inhibiting the dissolution of iron by hydrochloric acid. (1) Preparation of test solution (1-1) Test solution 1 (ANI) Add 1.0ml of 1% aniline aqueous solution and 19.0ml of water to 20.0ml of 4M hydrochloric acid to prepare test solution 1.
was prepared. (1-2) Test solution 2 (DTMA-ANI) 20.0 ml of 4M hydrochloric acid, 1.0 ml of 1% aniline aqueous solution, 1.0 ml of 0.5% dodecyltrimethylammonium chloride aqueous solution and 18.0
Test solution 2 was prepared by adding ml of water. (1-3) Test solution 3 (TEA) Test solution 3 was prepared by adding 1.0 ml of 1% triethanolamine aqueous solution and 19.0 ml of water to 20.0 ml of 4M hydrochloric acid. (1-4) Test solution 4 (DTMA-TEA) To 20.0 ml of 4M hydrochloric acid, add 1.0 ml of 1% triethanolamine aqueous solution, 1.0 ml of 0.5% dodecyltrimethylammonium chloride aqueous solution, and 18.0 ml of water to prepare the test solution. 4 was prepared. (2) Test method The test was conducted in the same manner as Test Example 3. (3) Test results The results were as shown in Table 4.

〔Effect of the invention〕

Dissolution and corrosion of metal can be suppressed during pickling in metal surface treatment. A clean surface finish can be formed without leaving an oxide film during pickling in metal surface treatment.

Claims (1)

[Claims] 1. An additive for acid solutions for pickling, characterized by comprising dodecyltrimethylammonium chloride, and one selected from the group consisting of polyvinyl alcohol, diethylene glycol, hexamethylenetetramine, aniline, triethanolamine, and mixtures thereof.