Preparation method of anticorrosive polyurea coating

Abstract

The invention belongs to the field of metal corrosion and protection and discloses a preparation method of an anticorrosive polyurea coating. The preparation method comprises processes of preprocessing a metal structure, removing oil, performing sand blasting, treating a metal surface, drying, spraying bottom polyurea paint and spraying surface polyurea paint. The preparation method is characterized in that an inositol phosphate solution is adopted in the metal surface treatment to form a chemical conversion film of inositol phosphate on the surface a the metal structure substrate; the bottom polyurea paint is aromatic polyurea paint; the surface polyurea paint is an aliphatic polyurea paint; the metal comprises steel, aluminum alloy and a zinc-plated steel structure; and the coating is 500-1500 mu m thick, the bottom layer is 300-1200 mu m thick, the surface layer is 200-400 mu m thick, and the bonding strength of the coating is higher than 10MPa. The preparation method provided by the invention is simple in process, convenient to operate and free from coating a primer.

Description

technical field [0001] The invention belongs to the field of metal corrosion and protection, in particular to a preparation method of a polyurea anticorrosion coating. Background technique [0002] Polyurea coating is a new type of coating developed on the basis of polyurethane coatings. It is prepared by the reaction of isocyanate and amino-terminated compounds. Compared with polyurethane coatings, polyurea coatings have the following outstanding advantages: 1) The solid content is 100%, that is, Does not contain any organic solvents, low pollution; 2) Short curing time, 30S can reach touch dry, some even gel in a few seconds; 3) Large film thickness, up to millimeter level after one spraying, spraying efficiency High; 4) Excellent performance, high strength, good flexibility, wear resistance and elasticity. [0003] Polyurea coatings are divided into two components, A and B. Component A is a curing agent composed of polyisocyanate, including isocyanate monomers, polymers,...

AI Technical Summary

Problems solved by technology

However, when polyurea coatings are used for anticorrosion of steel structures, there are the following problems: 1) The viscosity of polyurea coatings is high and the penetration is poor, so it is difficult to penetrate into the micropores of traditional phosphating membranes, causing the polyurea coatings to contact with the metal substrate 2) The film-forming speed of polyurea coating is too fast, and it is prone to bare substrate and shrinkage phenomenon when preparing thin polyurea coating, which leads to the decrease of the overall anti-corrosion performance of polyurea coating; 3) The elasticity of coating is too high , once cathodic hydrogen evolution corrosion occurs, it is easy to penetrate along the surface of the substrate and cause large-scale peeling, the thicker the coating, the more obvious; 4) The preparation time of polyurea coating mainly depends on the primer time, and a primer takes 6-24h ;5) In order to improve the anti-corrosion performance of the coating, generally 2000-3000μm thick coating is used, which results in high price and limited popularization and application