High-thixotropy water-based double-component high-glossiness automotive topcoat and preparation method thereof

Abstract

The invention belongs to the technical field of coatings and particularly relates to a high-thixotropy water-based double-component high-glossiness automotive topcoat and a preparation method thereof.The topcoat is prepared from japanning and a cross-linking agent according to the weight ratio of 100 to (13.5-15), wherein the japanning is prepared from a high-hydroxyl-value water-based acrylic copolymer dispersion, a low-hydroxyl-value water-based acrylic copolymer dispersion, a leveling agent, a dispersant, a pH value regulator, a film coalescing aid, titanium dioxide, a non-ionic associative thickener, an alkali swelling thickener and deionized water, and the cross-linking agent is prepared from a hydrophobic HDI trimer, HDI based hydrophilic polyether modified aliphatic polyisocyanateand propylene glycol methyl ether acetate. The topcoat has the advantages of long application period, high hardness and good thixotropy. The wet film thickness is 70 microns or more, the defects of sagging, blistering and dark bubbles do not exist, and the technical problems of poor fullness and poor appearance caused by low solid content in construction of water-based coatings are solved.

Description

technical field [0001] The invention belongs to the technical field of coatings, and in particular relates to a high-thixotropic water-based two-component high-gloss automotive topcoat and a preparation method thereof. Background technique [0002] Automotive body coatings are multi-layer systems that generally include a primer layer, a mid-coat layer and a topcoat layer. The topcoat is the outermost layer of automobile painting. The overall effect after painting is displayed through the topcoat layer. Therefore, the topcoat must have a certain hue, gloss, fullness and good weather resistance. Most of the existing topcoats are solvent-based, and the volatilization of organic solvents will cause serious environmental pollution problems. Moreover, solvent-based coatings also have safety problems in transportation, storage and use. [0003] Due to the stricter and stricter national environmental protection policies and the emission control of volatile organic compounds (VOC),...

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Problems solved by technology

[0005] In order to solve the problems existing in the prior art (such as the slow drying speed of the water-based automotive topcoat, poor fullness, easy sag during construction, and the paint layer is prone to defects such as prickly heat and dark bubbles), the invention provides a high-touch paint. Denatured water-based two-component high-gloss automotive topcoat. This topcoat has the characteristics of long pot life, high hardness and good thixotropy. The wet film thickness is more than 70 μm without sagging, prickly heat and dark bubbles. It solves the problems of water-based coatings. Low solid content in construction leads to technical difficulties in fullness and poor appearance

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