Abstract:
［Objective］To environmentally friendly and efficiently prepare polyester resins forpowder coatings under atmospheric pressure.［Methods］ A composite catalyst system containing a hydrolysis-resistant hybrid titanium catalyst（DH-HyTi HCEO-type）and a novel titanium-tin（Ti-Sn） catalyst was used to synthesize general polyester resin for powder coatings，and the application effect of the composite catalyst in polyester resin synthesis was explored.［Results］The HCEO-type hybrid titanium catalyst could be used to synthesize polyester resins under atmospheric pressure with an optimal dosage of 150 μg/g（mass ratio of titanium to theoretical polyester resin）. The esterification reaction time was obviously shorter than that of tetrabutyl titanate（TBOT）. The esterification rate of the synthesized polyester resin was basically the same as that of monobutyl tin oxide（MBTO）， and the synthesized polyester resin was colorless and transparent. The HCEO catalyst demonstrated exceptional hydrolysis resistance and remained consistent catalytic efficiency after hydrolysis reaction. The Ti-Sn-1 composite catalyst（the dosage of monobutyl tin oxide and HCEO was 0. 05% and 0. 2% of the raw material mass，respectively）had the lowest esterification activation energy（38. 13 kJ/mol）， and the catalytic esterification time was reduced by 45 min compared to that of MBTO. The organic tin content of final product was 0. 05%（mass ratio of reaction raw materials），complying with REACH regulations（ <0. 1%）. The synthesized polyester resin displayed a number-average molecular weight（Mn） of 5 001，viscosity of 4 650 mPa·s（200 ℃）， acid value of 28. 9 mgKOH/g，and glass transition temperature（Tg）of 61. 1 ℃ . These properties were similar to those of polyester resin prepared usingMBTO. Additionally，it featured a narrower molecular weight distribution（PDI=1. 63）， and superiorstorage stability due to the hydrolysis resistance of HCEO. The colorimetric performance of the resinprepared using Ti-Sn composite catalyst was better with a b-value of 0. 68.［Conclusion］ The performance of polyester resin synthesized using Ti-Sn composite catalyst was not significantly different from that of resin using MBTO，indicating that the composite catalyst could replace organotincatalysts in the synthesis of general-purpose polyester for powder coatings under normal pressure.
Key words:
hybrid titanium catalyst,
powder coating,
polyester resin,
reaction efficiency,
organotin
摘要： 【目的】在常压下绿色、高效地合成粉末涂料用聚酯树脂。【方法】采用绿色耐水解的杂化钛系催化剂（DH-HyTi杂化钛催化剂， HCEO型）合成通用型粉末涂料用聚酯树脂，并制备了新型钛 -锡（ Ti-Sn）复合催化剂，以探究其在合成中的应用效果。【结果】杂化钛催化剂 HCEO能够在常压下合成聚酯树脂，其钛的质量比（钛的质量与聚酯树脂理论质量的比）为 150 μg/g，催化酯化反应时间较钛酸四丁酯（ TBOT）的明显缩短，合成的聚酯树脂酯化率与采用单丁基氧化锡的基本一致且无色透明；并且该杂化钛催化剂的耐水解性能突出，在水解反应后仍保持基本一致的催化效率；复合催化剂 Ti-Sn-1（单丁基氧化锡用量为原料质量的 0. 05%，HCEO用量为原料质量的 0. 2%）的酯化反应活化能最低，仅为 38. 13 kJ/mol，催化酯化时间较单丁基氧化锡的缩短了 45 min；且有机锡含量（以反应原料质量计）为 0. 05%，符合 REACH法规要求（ <0. 1%）；得到的聚酯树脂数均相对分子质量（ Mn）为 5 001，黏度为 4 650 mPa·s（200 ℃），酸值为 28. 9 mgKOH/g，玻璃化转变温度（ Tg）为 61. 1 ℃，这些性能与采用单丁基氧化锡制得的聚酯树脂相近，且相对分子质量分布更窄（PDI=1. 63），又由于 HCEO耐水解，所以复合催化剂制得的聚酯树脂贮存稳定性更好；复合催化剂合成的聚酯树脂的色度更好， b值可达 0. 68。【结论】采用钛 -锡复合催化剂合成的聚酯树脂的性能与单丁基氧化锡催化剂合成的相差不大，可见该类复合催化剂可以代替有机锡类催化剂在常压下合成通用型粉末涂料用聚酯。
关键词:
杂化钛催化剂,
粉末涂料,
聚酯树脂,
反应效率,
有机锡
CLC Number: