Method for the preparation of modified poly(alkylene terephthalate) employing in situ titanium-containing catalyst

摘要

A process of preparing a modified polyalkylene terephthalate by melt polycondensation comprising reacting an alkylene diol and polyethylene terephthalate, wherein polymerization occurs in the presence of a catalyst complex formed by reaction of tetra(alkyl) titanate and a compound selected from phosphorus-containing compounds, nitrogen-containing compounds, boron-containing compounds, and combinations thereof.

主权项

1. A process of preparing a modified polyalkylene terephthalate from recycled polyethylene terephthalate, the process comprising:
forming a catalyst consisting of the reaction product of tetra(C1-C8 alkyl) titanate and phosphoric acid, wherein the molar ratio of the phosphoric acid to the tetra(C1-C8 alkyl) titanate is from 0.05:1 to less than or equal to 2:1; depolymerizing the polyethylene terephthalate by combining the polyethylene terephthalate, in the presence of the catalyst, with a dihydric alcohol selected from the group C2-C20 alkylene diols to obtain a molten mixture; and polymerizing the molten mixture in the continued presence of the catalyst and C3-C20 alkylene diol, which alkylene diol is added during or after depolymerization such that the same or different alkylene diol can be present during depolymerization and polymerization, to yield modified polyalkylene terephthalate.