高固含量聚醚型水性聚氨酯的合成与影响因素

以异佛尔酮二异氰酸酯(IPDI)和六次甲基二异氰酸酯(HDI)为硬段、聚醚(N-220)为软段,二羟甲基丙酸(DMPA)为亲水性物质、乙二胺为后扩链剂和三羟甲基丙烷(TMP)为交联剂等,合成了高固含量的聚醚型水性聚氨酯(WPU)乳液。采用衰减全反射红外光谱(ATR)对其结构进行了表征,并探讨了溶剂(丙酮)和DMPA含量、反应过程中预聚体的黏稠度、扩链剂的加料顺序和扩链时间等因素对WPU乳液固含量的影响。实验结果表明,在保持其他条件不变的情况下,即n(-NCO)∶n(-OH)=1.2∶1、m(HDI)∶m(IPDI)=2∶1和n(TMP中-OH)∶n(聚醚中-OH)=1∶4、w(DMPA)=1.5%(相对于树脂而言)且w(丙酮)=50.4%～75.5%(相对于树脂而言)时,在预聚反应过程中,若体系较稀(即黏度较低),在乳化时先加入乙二胺,待反应4～7min后再加入水,如此易制得稳定的高固含量(40%～46%)聚醚型WPU乳液。

Synthesis and effect factors of waterborne polyurethane with high solid content based on polyether polyols

With isophorone diisocyanate(IPDI) and hexamethylene diisocyanate(HDI) as hard chain segment, polyether polyols(N-220) as soft chain segment,dimethylol propionic acid(DMPA) as hydrotropic substance, ethylenediamine as chain extender and tri(hydroxymethyl)propane(TMP) as cross linker,the waterborne polyure-thanes (WPU) with high solid content based on polyether polyols were synthesized. The WPU’s structure was charac terized by ATR,the influences of content of solvent(acetone) and DMPA,thin or thick of prepolymer in reaction process,charging sequence and reaction time of chain extender were discussed on solid content of WPU. The experiment results showed if systems was thin(namely viscosity was lower)in the process of prepolymer reaction, according to first adding ethylenediamine,then reaction about 4-7 min,finally adding water,so stable WPU emulsion with high solid content (namely 40%-46%) based on polyether polyols was easily prepared when other conditions was invariable,namely molar ratio of -NCO to -OH was 1.2∶1,mass ratio of HDI to IPDI was 2∶1,molar ratio of -OH in TMP to -OH in polyether polyols was 1∶4,mass fraction of DMPA was 1.5% in resin and mass fraction of acetone was 50.4%-75.5% in resin.