低VOC含量水性亚硫酸氢钠封闭型聚氨酯固化剂的制备和表征

Preparation and Characterization of Low VOC Waterborne Sodium Bisulfite-Blocked Polyurethane Curing Agent

用异佛尔酮二异氰酸酯(IPDI)、聚醚多元醇、二羟甲基丙酸(DMPA)和含活性基非离子亲水化合物(AD)为主要原料,以亚硫酸氢钠(NaHSO3)为封闭剂,合成了低VOC含量、高封闭率的水性封闭型聚氨酯固化剂。采用先成盐后封闭的制备工艺,避免了助溶剂的使用。研究了n(—NCO)∶n(—OH)、DMPA、AD等亲水改性剂用量、封闭反应的温度、时间、NaHSO3用量及其质量分数等因素对封闭反应的影响。用FT-IR和DSC对产物进行了表征,结果显示,—NCO基团被完全封闭,由DSC确定了产物的解封温度在97.5～130℃。

Waterborne blocked polyurethane curing agent with low VOC content and high blocked degree was prepared using isophorone diisocyanate（IPDI） , polyether polyol, dimethylolpropionic acid （DMPA） and nonionic hydrophilic compounds with active group（AD） as the main materials and sodium bisulfite as blocking agent. The co - solvent was avoided to be used because the blocking reaction was carried out after salification in the new preparation technology. The effect of nNCO/nOH, DMPA content, the temperature and time of blocking reaction, NaHSO3 content and its solution concentration on the blocking reaction were carefully studied. The products were characterized by FTIR and DSC. The results showed that the NCO groups were blocked completely and the deblocking temperature determined by DSC was about 97.5-130℃.