双组分聚氨酯密封胶的制备与性能研究

Study on preparation and properties of two-component polyurethane sealant

以聚醚多元醇和4,4′-二苯基甲烷二异氰酸酯（MDI）为主要原料,制备了双组分PU（聚氨酯）密封胶,并优选了端—NCO基预聚体的合成条件。研究结果表明：当n（3官能度聚醚多元醇）∶n（2官能度聚醚多元醇）=1.2∶1.0时,加入MDI后,70~75℃反应4 h,可得到w（—NCO）=4.5%的端—NCO基预聚体;当A组分、B组分按照R=n（—NCO）∶n（—OH）=1.1∶1~1.4∶1配比混合均匀时,制得的PU密封胶具有良好的粘接性能和热稳定性。

With polyether polyol and 4,4＇-diphenyl methane diisocyanate （MDI） as main raw materials, the two-component PU （polyurethane） sealant was prepared, and the synthesis conditions of prepolymer with end -NCO group were preferred. The research results showed that the end --NCO group prepolymer with 4.5% -NCO could be obtained when molar ratio of n（3 functionality-polyether polyol） ： n（2 functionality-polyether polyol） was 1.2： 1.0, MDI was introduced into system, and reaction temperature and time were 70-75 ℃ and 4 h respectively. The PU sealant had the good bonding properties and thermal stability when the A-component and B-component were evenly mixed by R value or molar ratio of--NCO to --OH at 1.1 ： 1-1.4： 1.