自然光固化水性聚氨酯树脂的制备与性能

Preparation and Properties of Natural Light Cured Waterborne Polyurethane Dispersions

合成了可自然光固化的季戊四醇三丙烯酸酯(PETA)和甲基丙烯酸羟乙酯(HEMA)混合封端型水性聚氨酯树脂。研究了PETA和HEMA的摩尔比(n1∶n2)对聚氨酯膜的硬度、耐溶剂性、凝胶含量和力学性能的影响,以及光引发剂种类和用量对固化速率的影响。结果表明,随着PETA在混合封端剂中含量的增大,聚氨酯膜的分子结构由线性转变为交联结构,漆膜的凝胶率、拉伸强度和模量逐渐增加,断裂伸长率降低。当n1∶n2为4∶6时,聚氨酯膜表现出最佳的耐溶剂性;复配型光引发剂的质量分数为2%时,在自然光照射下,树脂固化时间最短。

Natural light curable water based polyurethane dispersions terminated by the mixture of pentaerythritol triacrylate (PETA) and methacrylate (HEMA) were synthesized. The effect of the molar ratio (n1 ∶ n2) of PE-TA and HEMA on the hardness, solvent resistance, gel content and mechanical properties of the films was researched. The effects of photo initiators and content on the curing time of the polyurethane films were investigated respectively. The results showed that, with an increase of PETA content in the mixed endcapping reagents, the molecule structure of polyurethane films was transformed from the linear to the crosslinking structure and the gel content, tensile strength and modulus of the PU films were increased gradually, while the elongation at break was decreased. The polyurethane film exhibited the best solvent resistance when n1 ∶ n2 was 4 ∶ 6. When the mass fraction of the complex initiator was 2%, the curing time for PU dispersion was the shortest under natural light.