PBT树脂合成中催化剂性能的研究

以对苯二甲酸(PTA)和1,4-丁二醇(BD)为原料,采用直接酯化法合成聚对苯二甲酸丁二醇酯(PBT);比较了钛酸四异丙酯(TPT)、钛酸四丁酯(TBT)以及自制的复合催化剂(TY)3种催化剂的催化活性;讨论了催化剂类型及其用量对酯化速率、酯化率、四氢呋喃(THF)生成量、聚合反应速率和PBT物理性能的影响。结果表明:在催化剂加入量(相对于PTA催化剂的Ti含量)为200～600μg/g时,TY,TPT和TBT催化剂的酯化率均能达到90%,TY催化剂较TPT和TBT能有效地提高酯化反应和聚合反应的速率,并能减少THF的生成量;采用TY催化剂,酯化率达95%,THF生成量降低20%～40%,聚合速度提高30%～50%,得到的PBT特性黏数达到0.880 dL/g,产品色相L值最高为79.19,b值最低为0.23;TY催化剂的催化活性较TBT和TPT高,而TBT催化剂稍优于TPT催化剂。

Performance of catalysts for PBT synthesis

Polybutylene terephthalate(PBT) was synthesized from terephthalic acid(PTA) and 1,4-butanediol(BD) via direct esterfication.The catalytic activity of tetraisopropyl(TPT),tetrabutyl titanate(TBT) and self-made composite catalyst(TY) was compared.The effects of catalyst variety and amount on the esterification reaction rate,esterification conversion rate,tetrahydrofuran(THF) yield,polymerization reaction rate and physical properties of PBT were discussed.The results showed that TY,TPT and TBT all provided the esterification conversion rate up to 90%,and TY can increase the reaction rates of esterification and polymerization and decrease the THF yield more efficiently when the catalyst addition was 200-600 μg/g(Ti content based on PTA);TY provided the esterification conversion rate up to 95%,THF yield with a decrease of 20%-40%,polymerization reaction rate with an increase of 30%-50% and the resulting product had the intrinsic viscosity of 0.880 dL/g and the maximum L value of 79.19 and the minimum b value of 0.23;TY had the highest catalytic activity among these three catalysts and TBT was slightly better than TPT.