阳离子有机硅聚氨酯自交联乳液的制备和应用

Preparation and application of cationic organosilicone polyurethane emulsion

聚醚与 2 ,4-甲苯二异氰酸酯发生预聚 ,得到淡黄色的以 - NCO为端基的预聚体 ,用小分子扩链剂扩链 ,再加入羟基硅油进行改性 ,最后加亲水扩链剂反应 ,制得含有阳离子的预聚体 ,加有机酸成盐乳化得蓝光乳白微透明乳液。这种自乳化阳离子有机硅聚氨酯乳液 ,可明显提高涂膜的光亮性、柔软性、抗水性和手感 ,该产品不仅可以用于皮革涂饰 ,还可用作手感剂、防水剂等。

The -NCO terminated prepolymer was prepared from diol polyether, D4, and 2,4-tolyldiisocyanate, and the prepolymer was extended with diol monomer and Si to introduce cationic groups, then the above product was neutralized to improve its ameliorative water dispersion, thus the cationic organosilicone polyurethane emulsion was prepared. The relationship between structure and properties of the emulsion was analyzed by IR, SEM, DSC and TDA. The factors affecting stability of the emulsion and coating properties were discussed. The emulsion with good stability was obtained when NCO/OH was 1.1～1.5, content of hydroxyl silicon oil was about 3%, and content of cationic group was above 15%. Optimum prepolymerization temperature was 60℃ and time was 1 h, and pH value of the emulsion should be 4～6 to ensure its good self-emulsifyingability. The emulsion could obviously improve brightness, softness, water resistance of coating, and could be used as coating finish, hand-feeling agent, and waterproofing agent for leather.