JPS635478B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention eliminates smuts, rust, butts, etc. on metal surfaces.
This invention relates to an electrolytic cleaning solution used for anodic electrolytic cleaning of oils and fats. Conventionally, when metal surfaces are anodic electrolytically cleaned, an alkaline substance such as caustic alkali, silicate, carbonate, phosphate, or polymerized phosphate is used alone as an electrolyte, or cyanide is added to this alkaline substance. Complexing agents such as sodium chloride, EDTA, sodium gluconate, triethanolamine, mannitrate, and sorbitol have been used in combination. Among these, when using sodium cyanide in combination, the cleaning ability is excellent, but it is highly toxic and has the disadvantage of requiring a large amount of wastewater treatment cost, which is not preferable. Also
The combined use of carboxylic acid salts such as EDTA sodium gluconate, sorbitate, mannitrate, polyhydric alcohols, etc. has the advantage of not being toxic, but it is not preferred because the cleaning properties are poor. Furthermore, among amino alcohols, monoethanolamine and diethanolamine are not preferred because they have poor cleaning properties, but triethanolamine and triisopropanolamine have relatively good cleaning properties. However, these metals form metal complexes with metal ions having a large stability constant and become soluble in water, making it extremely difficult to remove heavy metals from the waste water of the cleaning solution, which is not preferred. The present inventors conducted various studies in an attempt to develop an electrolytic cleaning solution with excellent cleaning properties and wastewater treatment properties, and found that it can be obtained by reacting and adding 1 to 5 moles of an epoxy compound to one active hydrogen atom in an aliphatic amine. It has been found that by using a mixture of amino alcohols and an alkaline compound as a conductive agent, excellent cleaning effects can be exhibited and wastewater treatment can be facilitated. The present invention is based on these findings, and
The anodic electrolytic cleaning solution used for surface treatment of metals consists of: 1 an inorganic alkali salt 1 g/or more; 2 an amino alcohol to which 1 to 5 moles of an epoxy compound have been reacted and added per active hydrogen atom of an aliphatic amine 1 g/or more. This is an anodic electrolytic cleaning solution characterized by: In the present invention, aliphatic amines include ethylenediamine, diethylenetriamine, triethylenetetramine, dipropylenetriamine, 3-
(2-aminoethyl)aminopropylamine, N,
N'-bis-(3-aminopropyl)ethylenediamine, pentapropylenehexamine, polyethyleneimine, etc. are used, and highly reactive epoxy compounds such as ethylene oxide, propylene oxide, epichlorohydrin, and glycidol are used. Generally, a low molecular weight epoxy compound containing no halogen element is preferred. When using (1) ethylenediamine, (2) diethylenetriamine, or (3) triethylenetetraamine as the aliphatic amine, the amino alcohol used in the present invention mainly depends on the number of moles of the epoxy compound added. This is considered to be obtained. (1) When using ethylenediamine (2) When using diethylenetriamine (3) When using triethylenetetraamine Next, as the inorganic alkali salt, caustic alkali, silicate, carbonate, phosphate, polymerized phosphate, etc. are used singly or in combination of two or more. If necessary, one or more polyhydric alcohols such as sorbitol and mannitol may be used. When the electrolytic cleaning solution of the present invention is used to anodicly electrolyze the processed material, the total concentration of the inorganic alkali salt and amino alcohol in the electrolyte should be 10 to 200 g/, and the pH of the solution should be 10 or more. The object to be treated and a carbon plate or iron plate are immersed in this highly alkaline solution, the object to be treated is used as an anode, and the current density is 0.5A/
Perform by turning on the power at dm ² or higher. The reason why the cleaning effect of the present invention is excellent is not clear, but in the highly alkaline region, the amino alcohol forms a metal complex with the metal oxide on the metal surface, and the metal oxide is dissolved from the metal surface, and at the same time, the cleaning effect is excellent. It seems that the dirt dissolves into the cleaning solution. In addition, the amino alcohol of the present invention has an amino group in its molecule, so it can effectively remove contaminants from high electric density areas, and it also has a hydroxyl group, so it can clean contaminants from low current density areas. As a result, compared to conventional cleaning agents, it not only shows superior cleaning performance even at low current densities, but also has good cleaning action over a wide range of current densities from low to high current densities. Conceivable. The wastewater after cleaning the processed material using the cleaning solution of the present invention is separated when the pH of the wastewater is set to 6 to 9, as the ability to complex heavy metal ions decreases and they precipitate as hydroxides. Can be removed. Therefore, if the cleaning solution of the present invention is used, conventional EDTA,
Easier wastewater treatment compared to those using gluconate, aminocarboxylate and hydroxycarboxylate. Therefore, if the cleaning solution of the present invention is used, the current density is lower than that of conventional cleaning agents, and it not only shows excellent cleaning performance, but also shows good cleaning effects in a wide range from low current density to high current density, and the processing It is also easy to remove heavy metal ions from the waste liquid afterwards. Example 1 A cleaning liquid was prepared by adding 50 g of sodium hydroxide to 50 g of an amino alcohol obtained by blowing 4 mol of ethylene oxide into a mixed solution of 1 mol of ethylenediamine and 10 mol of water (hereinafter referred to as cleaning liquid A). Example 2 A cleaning liquid was prepared by adding 30 g of sodium metasilicate and 30 g of sodium hydroxide to 30 g of amino alcohol obtained by blowing 4 mol of propylene oxide into 1 mol of ethylenediamine and reacting it (hereinafter referred to as cleaning liquid B). Example 3 20 sorbitol per 30 g of amino alcohol obtained by blowing 5 mol of glycidol into a mixture of 1 mol of diethylenetriamine and 6 mol of water.
A cleaning solution was prepared by adding 50g/g of sodium hydroxide and 50g/ of sodium hydroxide (hereinafter referred to as cleaning solution C). Example 4 Reagent amino alcohol (ethylenediaminetetraN,N,N',N'ethanol) 20g/trisodium phosphate 10g/and sodium hydroxide 30g/
A cleaning solution was prepared by adding (hereinafter referred to as cleaning solution D). In addition, as a comparative example, (1) Cleaning liquid: 50 g of sodium gluconate / 50 g of sodium hydroxide / (2) Cleaning liquid: 50 g of EDTA / 50 g of sodium hydroxide / were prepared, and 250 ml of each of these cleaning liquids was placed in a Hull cell container, and the test piece described below was used as an anode. Using an iron plate as the cathode, a cleaning test was conducted at a treatment temperature of 50°C, a treatment time of 1 minute, and a current of 2A, and the following results were obtained. The test pieces were steel plates eroded in 10% hydrochloric acid at 60 to 70°C to form black acid smuts, which were then washed with water.

[Table] Judgment of the above test results was performed by wiping the test piece after the test with paper and by visual inspection. 〇 indicates that the smut has been completely removed, △ indicates that it has been partially removed, and × indicates that the smut has not been removed.

Claims (1)

[Scope of Claims] 1. In the anodic electrolytic cleaning solution used for metal surface treatment work, (a) 1 g/or more of an inorganic alkali salt (b) 1 g/atom or more of an inorganic alkali salt per active hydrogen atom in the aliphatic amine.
An electrolytic cleaning solution comprising 1 g/or more of an amino alcohol to which 5 moles of an epoxy compound have been reacted.