封端型脂环族水性聚氨酯的合成

Synthesis of water soluble aliphatic blocked polyurethane

采用预聚体-封端混合法,即异佛尔酮二异氰酸酯（IPDI）中异氰酸酯和聚醚多元醇（PEG）的醇羟基预聚反应后,将剩余的NaHSO3封端最终所剩异氰酸酯基,合成脂环族水性聚氨酯.探讨了异氰酸酯指数（R值）、中和度等因素对其性能的影响.聚酯多元醇水性聚氨酯的成膜性好,膜的强度和硬度好,聚醚型的贮存稳定性要好于聚酯型的;羧酸含量为2%时,乳液的分散效果较好,而耐水性并未发生变化;R值为2.0,中和度为90%-100%时合成的乳液效果较为理想.同时确定了预聚反应温度和时间（60℃,2h）、封端的温度和时间（0-5℃,30min）、封端剂的用量（NaHSO3/NCO为1.2）以及促进剂用量（Na2SO3/NaHSO3为0.3）.

The waterborne aliphatic blocked polyurethane（WBPU）was synthesized with polyethylene glycol,and IPDI as raw materials and NaHSO3 as the blocking agent by prepolymer mixing process,in this process isocyanate base containing in IPDI is reacted with alcohol hydroxyl.The influence of NCO/OH ratio and neutralization on the product properties was discussed.The result shows that polyester polyol has excellent film forming with strength and hardness,while the storage stability of polyethylene glycol is much better than that of polyester polyol;Lotion decentralized effect is better when the content of carboxylicacid is 2%;the effect of lotion is ideal when R value is 2.0 and neutralization is 90%～100%.At the same time,the influence of reaction time and temperature for prepolymer,blocking temperature,capped time and blocking agent on stability of prepatation was also discussed.