Patent ID: 8791225

Claim:
A method for making titanium-catalyzed polyethylene terephthalate resin, comprising: mixing a terephthalate component and a diol component to form a polyethylene terephthalate reaction mixture; reacting the terephthalate component and the diol component in the polyethylene terephthalate reaction mixture to form polyethylene terephthalate precursors; adding a titanium-nitride polycondensation catalyst to the polyethylene terephthalate reaction mixture as a suspension in the diol component, wherein the titanium-nitride polycondensation catalyst is added to the reaction mixture when the polyethylene terephthalate precursors achieve an average degree of polymerization of between 3 and 6; and polymerizing the polyethylene terephthalate precursors via melt phase polycondensation to form a polyester melt comprising polyethylene terephthalate polymers; wherein the titanium-nitride polycondensation catalyst consists of a titanium-nitride catalyst and the titanium-nitride catalyst is the only catalyst present during the reacting and the polymerizing.