用薄膜蒸发器分离聚氨酯固化剂中游离TDI关键技术开发

Exploiture of the Key Technique for Separation TDI from Polyurethane Curing Agent by Thin-film Evaporator

薄膜蒸发技术在几种常见的降低聚氨酯固化剂中游离甲苯二异氰酸酯(TDI)的方法中,是最经济有效的。然而在实际的蒸发操作过程中存在一个重要难题:固化剂难从设备中流出来,导致堵塞设备,出现事故。本研究从小试到中试进行系统研究,提出并实施了系列的解决方法:1在合成的过程中加大TDI/TMP的配比到质量比为4.6∶1,合成出分子量小的预聚物;2在反应后期加入万分之二的磷酸作为分离时候的副反应抑制剂;3改进薄膜蒸发器主体设备—蒸发柱,使之适合于分离TDI-TMP预聚物。通过这三个方面的改进,能完全避免分离TDI堵塞现象的发生。

Thin-film Evaporation is economical and efficacious technique in usual technique for separating TDI from polyurethane prepolymer. But Thin-film Evaporation technique is very difficult because prepolymer cured easily in Evaporator. This research from experimental study to industrialized study, put forward solution in series： 1 Synthesize low molecular prepolymer through increasing ratio of TDI/TMP to 4.6：1 ; 2 Add 0. 02% phosphate to prepolymer as depressant; 3 Improve on the body of Thin-film Evaporation suitable for separation TDI. After amelioration of these aspect, jam is not occured when separating TDI from polyurethane prepolymer with Thin-film Evaporator.