The reason for the paint explosion in the processing of coated products is that micro-cracks appear in the primer coating after severe deformation in tension and compression, and cause micro-cracks in the entire coating. When the microcracks are placed for a long time or at a higher temperature, aging problems will occur, and the cracks will become larger, thereby forming cracks in the coating. The main cause of microcracks in the primer coating is that the resin used in the formulation design of the primer is unreasonable, and the cross-linking reaction is severe during curing, resulting in insufficient flexibility of the primer coating, and the coating is prone to cracking after severe deformation.
Based on the analysis of the above reasons, the key to solving the problem of paint bursting is to improve the resin in the primer. Based on the analysis of the resin, through a large number of experiments and comparisons, a linear polyester resin with a larger relative molecular weight, lower hydroxyl value, and lower glass transition temperature was selected, and the relative molecular weight of the resin was reduced by adjusting the solvent in the formula. The effect on the viscosity of the coating after the quality is improved, and the T-bend aging of the coating after the resin is improved. After the coating is improved, the coating cracks are significantly reduced after the T-bend aging, and the coating basically has no cracks after the bending aging, which shows that the improvement has obvious effects
Source of this article:
Cai Feilong (Cold Rolling Plant of Baoshan Iron and Steel Co., Ltd., Shanghai 201900)
"Analysis and solution to the problem of paint explosion in the processing of color-coated panels for air-conditioning external units and household appliances"
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