有机硅改性聚酯的合成及其粉末涂料的性能

利用有机硅中间体合成了有机硅改性聚酯树脂。通过IR、GPC、SEM等分析了改性聚酯的结构与形态 ,用电子探针分析了改性聚酯的表面组成 ,考察了有机硅含量对改性树脂玻璃化温度、熔融黏度、对水的接触角及表面张力的影响。研究发现 ,改性聚酯中的含硅聚酯在表面富集 ,大大降低了聚酯树脂的表面张力 ,提高了其粉末涂料的涂膜耐候性。相对于纯聚酯树脂 ,有机硅质量分数为 1 %可使树脂的表面张力从 49.5降到 2 8.4mN/m ;经 2 1 6h中波紫外线照射后 ,涂膜的光泽保留率从 81 %上升到 91 .3 %。含有机硅质量分数超过 5 %后 ,涂膜的抗冲性能下降。

Siloxane-modified polyester:synthesis and features of its powder coatings

The siloxane-modified polyester resin for powder coatings was synthesized with Z-6018 siloxane intermediate introduced.The structure and morphology of the modified polyester were analyzed by IR,GPC and SEM,and the enrichment of the siloxane component on surface of modified resins was confirmed by electron probe microscopic analysis.The effect of siloxane content in the modified polyester on vitrification point,melting viscosity and contact angle against water as well as the surface tension of the modified resin were investigated.It was found that the surface tension of the modified polyester resin decreased greatly and the weather-resistance performance of the cured film for the corresponding powder coating became better,due to the enrichment of the siloxane containing polyester in the surface layer.As compared with the neat polyester,the surface tension of the modified polyester containing 1% siloxane was decreased from 49.5 to 28.4 mN/m and the gloss retention ratio of the coating film was increased from 81% to 91.3% when exposed to medium ultraviolet wave for 216 hours.But when the siloxane content in the modified resin exceeded 5%,the impact-resistance of the coating film became worse.