Study On Preparation And Performances Of Two-component Elastic Polyurethane Coatings

Two-component polyurethane coatings have been widely used in various fieldsbecause of their excellent performance. some of the special two-component elasticpolyurethane coatings have been used as a high-speed railway viaduct waterproofcoating surface coating materials because of its good waterproof performance andanti-aging properties. This study explored such preparation and properties oftwo-component elastic polyurethane coatings.Based on the performance requirements of two-component polyurethanecoatings,we design the isocyanate prepolymer. By selecting the the reaction time,reaction temperature and synthetic routes,we discussed the synthesis conditions ofelastic isocyanate prepolymer,and the process conditions were optimized.Accordingto the optimization of process conditions,ten groups of isocyanate prepolymer ofdifferent isocyanate group content (NCO%) were synthesised by adopting H12MDI,IPDI and synthesized polytetrahydrofuran. the NCO%and viscosity of prepolymershave been tested.Hydroxyl acrylic resin, binary polyester resin, poly-aspartic ester resin wereselected as component B of two-component polyurethane coating,based on theisocyanate prepolymer of synthesis. The effects of different resins for coating perf-ormance were investigated.Through testing performance,the formula of appropriateelastic isocyanate prepolymers was determined:IPDI and polytetrahydrofuran asmeterials,8.0~8.5%NCO.By adjusting the proportion of hydroxyl acrylic resin, binary polyester resin,polyaspartic ester resin, we explored its impact on film performance: coating tabledry time and working time have been gradually shortened with the ratio ofpolyaspartic acid ester resin increasing; paint film weather gradually becomes poorand loss of gloss are increasingly obvious with the ratio of polyester resin graduallyincreasing;coating the maximum tensile strength increases gradually and elongation atbreak decreases gradually with the ratio of acrylic acid resin graduallyincreasing.According to the requirements of performance,the formula of part B oftwo-component polyurethane elastic coating is determined,as well as the differentNCO/OH (NH) molar ratio of coating performance effects is explored.we get theoptimal NCO/OH (NH) molar ratio.This paper establishes the production process of a two-component elastic polyurethane coating, the requirement for raw materials and quality control ofproducts, and the method of product performance testing.