TDI三聚体改性水性聚氨酯分散体的合成与性能

Synthesis and Properties of Toluene Diisocyanate Trimer Modified Polyurethane Dispersion

采用预聚体混合工艺合成了甲苯二异氰酸酯(TDI)三聚体(TT)改性水性聚氨酯分散体(TPUD),考查了TT含量(占聚氨酯预聚体的质量分数)对水性聚氨酯分散体(PUD)稳定性和涂膜物理、化学性能的影响,热重分析(TGA)和傅里叶红外光谱(FT-IR)表征了TPUD的热稳定性与分子结构,研究发现:当TT添加量的质量分数≤3%时,TT的引入可以提高PUD涂膜的最终硬度和凝胶量,降低涂膜的吸水率和吸醇率,且对PUD的稳定性及涂膜外观和附着力无负面影响;当TT添加量的质量分数为3.0%时,涂膜综合性能最佳(硬度为0.70,吸水率为5.0%,凝胶量为78%);当TT加入量的质量分数≥4%,TPUD的成膜性变差,其涂膜的光泽与附着力下降,耐化学性也变差。TGA分析表明TT的引入提高了TPUD涂膜的热稳定性。

Novel aqueous polyurethane dispersions （TPUD） modified with toluene diisocyanate（TDI） trimer （TT） were synthesized via prepolymer mixing process. The effects of the TT contents on the physical - chemical properties of TPUDs and its films were discussed. The structures and thermal stability of TPUD films were characterized by TFIR and thermal gravimetric analysis （TGA）. The results show that the TT modifications improve the hardness and crosslinking degree, decrease the water/alcohol - absorption of the TPUD films. While the storage stability of TPUD and appearance, adhesive of TPUD films change little as the amount of rFl＇ under 3.0%. The TPUD film with 3.0% TT displays excellent physical - chemical properties including 0.70 of hardness, 78% of crosslinking degree and 5.0% of water absorption. However, the performance of films become not so good as the amount of TT ≥4.0% , which decreased in film formation ability, film gloss, adhesive, and chemical -resistance properties. TGA curves indicate that the TPUD films display better thermal stability than those of the common PUD films.