用封端与不封端聚醚胺制备聚脲涂层及其性能

Preparation of polyurea coatings with blocked and unblocked amino-terminated polyoxypropylene and their properties

用甲基异丁基酮(MIBK)封闭聚醚胺(D2000)得到了酮亚胺(D2000-MIBK),随后与六亚甲基二异氰酸酯三聚体混合而制备了封端后的聚脲涂层(PUA-1),并与未封端聚脲涂层(PUA-2)的性能进行对比。通过动态差示扫描量热法考察了D2000-MIBK与异氰酸酯体系的固化特性。结果显示,PUA-1的室温(25°C)凝胶时间为85.0 min。若高温快速固化,最佳固化温度为140°C,凝胶时间8.0min。PUA-1适用于手工刷涂或流水线喷涂,且140°C烘烤对涂层性能并无较大影响。PUA-1涂层的摆杆硬度、柔韧性和耐冲击性与PUA-2涂层相当,附着力和断裂伸长率更优,可施工时间大大延长。

A blocked amine called ketimine(D2000-MIBK)was prepared by blocking amino-terminated polyoxypropylene(D2000)with methyl isobutyl ketone(MIBK),and then blended with hexamethylene diisocyanate trimer to form a blocked polyurea coating(coded as PUA-1)whose properties were compared with those of an unblocked polyurea coating(coded as PUA-2).The curing characteristics of the D2000-MIBK/isocyanate system was studied by dynamic differential scanning calorimetry.The results showed that the gelation time of PUA-1 at room temperature(25℃)is 85.0 min.Considering the fast curing at a high temperature,the optimal curing temperature is 140℃,under which the gelation time is 8.0 min.The PUA-1 coating is suitable for manual painting or spraying in a production line.Baking at 140℃has little effect on its properties.The PUA-1 coating has comparable pendulum hardness,flexibility,and impact resistance to the PUA-2 coating,better adhesion and elongation at break,and much longer construction time.