温度和锡催化剂对WPU反应速率影响及乳化反应条件选择

Selection of emulsification condition and influences of temperature and tin-containing catalyst on reaction speed of waterborne polyurethane

以2,4-甲苯二异氰酸酯(TDI)、聚乙二醇(PEG)及N-甲基二乙醇胺(MDEA)等为原料,制备出一种亲水性阳离子型水性聚氨酯(WPU)乳液。通过跟踪测定预聚体中-NCO含量,分析了温度和锡催化剂用量对PU(聚氨酯)预聚反应速率的影响,并对后续乳化反应条件进行了选择。结果表明:PU预聚反应速率随温度升高和催化剂用量增加而增大;当温度为60℃、w(催化剂)=1.0%时,预聚反应迅速且平稳。采用低温乳化、先中和后乳化、将中间体加入水中以及低搅拌速率等方法,可以得到分散性好、气泡量低且性能稳定的WPU乳液。

A hydrophilic cationic waterborne polyurethane （WPU） emulsion was prepared with 2,4-toluene diisocyanate （TDI）,polyglyeol （PEG） and N-methyl diethanolamine （MDEA） as raw materials. The influences of temperature and tin-containing catalyst contents were analysed on reaction speed of PU （polyurethane） prepolymerization by tracing -NCO contents in the prepolymer, and the post-emulsification conditions were selected. The results showed that the reaction speed of PU prepolymerization was increased with increasing temperature or catalyst contents. The prepolymerization reaction was both rapid and stable when temperature was 60 ℃ and mass fraction of catalyst was 1.0%. The WPU emulsion with well dispersivity,lower bubble and stable performances could be obtained by emulsification with low-temperature and lower mixing speed after neutralization,intermediate product into water and other methods.