UV固化超支化水性聚氨酯涂料的制备

Preparation of UV-curable waterborne hyperbranched polyurethane coating

以自制单体6[N-氨乙基-2,2'-二羟甲基丙酰胺]、甲苯-2,4-二异氰酸酯(TDI)和2,2'-二羟甲基丙酸(DMPA)为主要原料,采用"准一步法"制备了新型WHBPU(水性超支化聚氨酯);然后以此为基体,通过接枝活性稀释剂(羟乙基丙烯酸酯)引入了光活性基团,制备出一种可UV(紫外光)固化的WHBPU涂料。研究结果表明:以固化速率为考核指标,采用单因素试验法优选出制备WHBPU涂料的最佳工艺条件是冰盐浴(-5℃)反应时间为2.0 h、油浴温度为60℃、油浴时间为2.0 h、w(活性稀释剂)=20%(相对于WHBPU乳液质量而言)、w(光引发剂)=3%(相对于干固乳液质量而言)和干燥条件为"室温(25℃)干燥2 h→50℃干燥2 h";此时,胶膜的固化速率相对较快、凝胶含量相对最大。

With self-made monomer 6[N-aminoethyl-2,2＇-bis （hydroxymethyl） propionamide] ,toluene-2,4- diisocyanate（TDI） and 2,2＇-dimethylol propionic acid （DMPA） as main raw materials, a novel WHBPU （waterborne hyperbranched polyurethane） was prepared by ＂quasi-one-stage＂ method. Then,with it as matrix resin,an UV （ultraviolet）-curable WHBPU coating was prepared by introducing photoactive group from grafting reactive thinner（hydroxyethyl acrylate）. The research results showed that with curing speed as evaluation index,the optimal process conditions of preparing WHBPU coating were preferred by single-factor experiment method when the reaction time at ice-salt bath （-5 ℃ ） was 2.0 h, temperature and time at oil bath were 60 ℃ and 2.0 h respectively, mass fractions of reactive thinner and photoinitiator were 20% in WHBPU emulsion and 3% in dried emulsion respectively,and the drying condition was＂drying 2 h at room temperature（25 ℃ ）→~drying 2 h at 50 ℃＂. Here ,the curing speed of adhesive film was relatively faster, the gel content was relatively maximal.