新型TMPLA水性聚氨酯分散体的合成及助成膜性能

Synthesis and film-forming performance of novel polyurethane aqueous dispersions

合成了新型扩链剂三羟甲基丙烷月桂酸单酯(TMPLA)并制备聚氨酯水分散体(n-PUD),取代小分子成膜助剂辅助高玻璃化温度(Tg)聚丙烯酸酯乳液(PA)成膜,以制备高性能超低挥发性有机化合物(VOC)含量水性木器涂料。研究了软/硬段质量比、NCO/OH及TMPLA/BDO摩尔比对n-PUD助成膜性能的影响。结果表明:随软/硬段质量比和NCO/OH摩尔比降低,PUD的助成膜能力增强;TMPLA引入能显著提高n-PUD的助成膜能力,优选TMPLA/BDO摩尔比4/2,NCO/OH摩尔比1.3,软/硬段质量比55/45时,n-PUD/PA按质量比25/75复配乳液在不加成膜助剂条件下能够在5℃形成连续透明成膜,制备的水性木器涂料VOC含量低至30 g·L-1。

The novel diol chain-extender trimethylol propane monolaurate（TMPLA） was synthesized to prepare novel polyurethane aqueous dispersions（n-PUD）,which was used as a coalescent to assist the film forming of high Tg polyacrylate emulsion. Effects of NCO/OH molar ratio, soft/hard segment contents and molar ratio of TMPLA/BDO on assistant-film-forming performance of n-PUD were studied. It was found that the assistantfilm-forming ability of PUD was increased with decreasing of NCO/OH molar ratio and hard segment proportions. PUDs modified with TMPLA displayed good assistant-film-forming ability. The optimized conditions to prepare assistant-film-forming n-PUD were as follows： molar ratios of TMPLA/BDO and NCO/OH were 4/2 and 1.3, respectively, mass ratio of soft/hard segment was 55/45, and then the blended latex with m（PUD）/m（PA） = 25/75 can form a continuous transparent film at 5℃ without coalescent with a VOC content as low as 30 g·L^-1.