封闭型阳离子水性聚氨酯的合成

Synthesis of Cationic Aqueous Polyurethane Having Blocked NCO Groups

以甲苯-2,4-二异氰酸酯(2,4-TDI)和聚乙二醇(PEG1000)为主要原料,以N-甲基-二乙醇胺(MDEA)为亲水扩链剂,以乙酰苯胺为封闭剂,采用自乳化法合成了水性聚氨酯。探讨了合成反应工艺条件,研究表明,较佳的合成工艺条件为:在65℃下合成预聚体,反应时间为75min,在75℃下加入封闭剂,反应时间随量的不同为1.5～2.5h,在40℃下加入扩链剂,反应时间为1h左右,在室温下同时完成盐化和乳化。通过红外谱图进行了表征。通过—NCO定性分析确定了解封温度。

Aqueous polyurethane was synthesized by self-emulsifying technique using 2,4-TDI and PEG 1000 as main starting materials, MDEA as hydrophilic chain extender and acetylaniline as blocking agent. The factors that influence the reaction process were investigated and optimized. It was found that when the synthesis of pre-polymer was carried out at 65℃ for 75 min followed by addition of blocking agent at 75℃ reacting for 1.5 h to 2.5 h, addition of the chain expender at 40℃ reacting for another 1 h as well as completion of salt formation and emulsification process at room temperature, better aqueous polyurethane could be obtained. The aqueous polyurethane was characterized by FITR. De-blocking temperature was ascertained by qualitative analysis of isocyanate group.