柠檬酸改性聚酯聚氨酯涂料的研究

以柠檬酸聚酯多元醇作为高固含量聚氨酯涂料的羟基树脂，通过正交试验优选了合成羟基树脂的工艺条件：n油酸：n柠檬酸：N1，4-丁二醇=1．0：1．0：3．5，反应在150～160℃下进行3h，再继续在190—200℃下反应2～3h。讨论了聚酯多元醇的羟值以及-NCO与-OH配比对涂膜性能的影响，当聚酯多元醇的羟值为148mgKOH／g，nNCO：nOH=1：2：1．0时，涂膜的各项综合性能最佳，达到了S01—3标准（聚氨酯清漆标准）。此外，研究发现催干剂二月桂酸二丁基锡浓度为mBTSL／m柠檬酸聚酯多元醇=0．08％-0．10％时，表干时间可达到25～30min。

Preparation of Polyester Polyurethane Coatings Modified by Citric Acid

The high - solid polyurethane coating is formulated with citric acid polyester polyol as hydroxyl resin. The process for preparing hydroxyl resin is optimized by the orthogonal experiment. The results show that the comprehensive performances of the obtained product can reach the best when the oleic acid, citric acid and 1, 4 - butanediol react between 150℃ and 160 ℃ for 3 hours at first and then continue to react at 190 - 200 ℃ for 2 to 3 hours with the molar ratio of 1.0 ： 1.0 ： 3.5. The effects of the hydroxyl value of polyester polyol and the ratios of --NCO to --OH on the properties of polyurethane coatings are discussed. It is proved that the properties of the coating film would meet the requirements of the S01 -3 Standard （the Standard of Polyurethane Varnish） when the hydroxyl value of polyester polyol is 148 mgKOH/g and the molar ratio of --NCO to --OH is 1.2 to 1. In addition, it is found that the dry - to - touch time can reach 25 - 30 min if the mass ratio of BTSL to citric acid polyester polyol is 0.08% - 0. 1%.