聚氨酯粉末涂料用超低羟值羟基聚酯树脂的研究

Research on Ultra-low Hydroxyl Value Hydroxyl Polyester Resin for Polyurethane Powder Coatings

在-NCO/-OH双组分聚氨酯涂料中一般采用含-NCO的异氰酸酯和含有端羟基的聚酯树脂反应制得,由于异氰酸酯固化剂价格昂贵,固化过程中产生大量有机挥发物,给人们的身体带来一定危害,也对环境造成不利的影响。因此,通过降低端羟基树脂中的羟基含量,达到减少异氰酸酯固化剂的用量,从而在达到节约成本的同时,符合国家绿色化发展和环保的要求。本文从醇类、酸类、羟值、黏度及助剂等方面探究了聚氨酯涂料专用端羟基聚酯树脂的制备方法。结果表明:在投料量为40 kg的前提下,醇酸比为1.077,添加TMP 0.65 kg、EG 3.0 kg、IPA 0.5 kg、ADA 1.5 kg,并添加PTA和NPG等醇酸,制得羟值为24 mgKOH/g的超低羟值聚酯树脂,通过添加适量颜料、助剂,即可制得流平性能优异、机械性能优良、成本较低的聚氨酯粉末涂料。

The-NCO/OH two-component polyurethane coatings were generally prepared by the reaction of NCO containing isocyanates and hydroxyl-terminated polyester resins.The isocyanate curing agents are expensive,and a large amount of volatiles are generated during the curing process,so it has a greater impact on health,and at the same time cause a certain degree of environmental damage.By reducing the hydroxyl content in the hydroxyl-terminated resin,the amount of isocyanate curing agent can be reduced,thereby saving costs,meeting environmentally-friendly coatings.The preparation methods of hydroxyl-terminated polyester resin for polyurethane coatings from the aspects of alcohols,acids,hydroxyl value,viscosity and additives were explored.The results showed that the polyurethane powder coatings with excellent leveling and mechanical performance was obtained by adding appropriate amounts of pigments and additives and the ultra-low hydroxyl value polyester resin with hydroxyl value of 24 mgKOH/g.Among then,the feeding quantity was 40 kg,the alkyd ratio was 1.077,the amount of TMP was 0.65 kg,EG was 3.0 kg,IPA was 0.5 kg,ADA was1.5 kg,and added with alkyd such as PTA and NPG.