Non-chromium pretreating agent for color coated steel plate

Abstract

The invention discloses a non-chromium pretreating agent for a color coated steel plate, which is a solution prepared by mixing solute formed by multiple substances with deionized water according to the weight percentage of 1:4 to 7, wherein the solute includes the following substances by weight percentage: 0 to 10 percent of organic carboxylic acid containing 4 to 18 carbon atoms or water soluble salt thereof, 5 to 30 percent of organic polymer with molecular weight ranging from 3000 to 200000, 10 to 15 percent of salt with oxidation capacity, 15 to 60 percent of inorganic fluorochemical with the function of complexation, 5 to 10 percent of high valence state titanium salt, 5 to 15 percent of inorganic zinc salt and 5 to 30 percent of inorganic phosphate. The pretreating agent of the invention does not include substances harmful to the environment and human bodies, such as high valence chromate, and the like; meets the RoHs requirement, and belongs to environment-friendly green products. Proved by experiments, the product of the invention can greatly improve the binding force between a coating and a galvanized plate, and can enhance the decay resistance of the coating.

Description

technical field [0001] The invention belongs to the field of steel production, in particular to a chromium-free pretreatment agent for color-coated steel sheets. Background technique [0002] The color-coated steel plate needs to be pretreated on the galvanized substrate before painting. The pretreatment process includes two parts. First, use a degreasing agent to clean the surface of the galvanized sheet to remove impurities and oil on the surface of the steel sheet, and then galvanized The surface of the board is coated with a pretreatment agent to produce a conversion film. The main purpose of the pretreatment of the galvanized sheet is to improve the bonding force between the coating in the color-coated steel sheet and the galvanized sheet, and at the same time improve the corrosion resistance of the color-coated steel sheet. [0003] At present, most domestic enterprises use chromate pretreatment agents for color-coated steel sheets. After chromate pretreatment, a chem...

AI Technical Summary

Problems solved by technology

Due to the low cost and simple process of chromate treatment, it has been widely used. However, hexavalent chromium is a serious carcinogen and has serious harm to the human body and the environment. With the enhancement of people's environmental awareness, governments of various countries have strictly restricted chromate The use and discharge of salt, the European Parliament and the European Council passed the RoHS directive in January 2003, restricting the import of various chromium-containing products

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