HDI三聚体改性聚氨酯水分散体的合成与性能

Synthesis and Properties of HDI trimer Modified Aqueous Polyurethane Dispersion

摘要:

采用己二异氰酸酯（HDI）三聚体（HT）合成聚氨酯水分散体（HPUD），考察了HT添加量对HPUD涂膜的耐水性、耐溶剂性、表干时间、硬度、光泽以及交联度的影响。通过粒径分布仪、热重分析仪（TGA）和傅里叶红外光谱（FT-IR）分别对HPUD乳液贮存过程中粒径的变化、涂膜热稳定性与分子结构进行表征，结果发现：引入5–10 wt%的HT可提高聚氨酯涂膜的表干速率和交联度，当HT添加量为10%时，HPUD涂膜具有最佳的综合性能：涂膜表干时间为45 min；交联度为80%，吸醇率为78%，吸水率为7%。同时，还发现HPUD涂膜硬度上升速率较快，但最终硬度较未改性PUD有所降低；粒径分析表明：当HT添加量≥20%时，HPUD贮存过程中乳液粒径增大，贮存稳定性下降；TGA分析表明：HPUD涂膜具有较好的热稳定性。

Abstract:

The HDI trimer (HT) modified aqueous polyurethane dispersions(HPUD) were synthesized and the effects of the contents of HT on the water- and solvent-resistance, the degree of crosslinking, hardness, gloss and surface drying time of the HPUD films were discussed. The particle sizes and its distributions, structures and thermal stability of HPUDs and its film were characterized by dynamic light-scattering technique (DLS), infrared spectra (IR) and thermal gravimetric analysis (TGA), respectively. The results show that introducing 5–10 wt% of HT into PUD improve surface dry rate and crosslinking degree of HPUD films, the HPUD films with 10% HT possess better performance including 45 min of the surface drying time, 80% of the crosslinking degree, 78% and 7% of the alcohol- and water-absorption rate. On the other hand, HPUDs display faster film hardness increasing rates and slightly lower final films hardness than those of the common PUDs without HT modification. DLS analysis results show that the particle sizes and its distributions increase and storage stability decrease with increasing the HT content in the HPUD up to 20% during the storage process. TGA curves indicate that the HPUD films possess good thermal stability.