Titanic Acid Coated Phosphate Catalyst for Polyester

The patent changes the chemical composition parameter by replacing antimony trioxide with titanium compounds (such as titanium tetraisopropoxide, titanium tetrabutoxide, or titanium halides) as the catalyst. This substitution maintains high catalytic activity while eliminating the harmful effects of antimony metal deposition that causes polyester darkening and contamination.

The patent employs titanium compounds that can be easily removed or decomposed after catalysis, leaving minimal residual contamination in the polyester product. The catalyst system is designed to be effective during the reaction but leaves the polyester clean, analogous to using a disposable tool that serves its purpose and is then discarded without leaving harmful residues.

The patent uses titanium compounds as a cost-effective alternative to expensive germanium compounds. The titanium catalyst system provides comparable catalytic activity while being significantly cheaper and less prone to distillation losses, maintaining stable catalyst concentration throughout the polycondensation process.

The patent changes the catalyst type from germanium compound to titanium compound, altering the chemical parameters to achieve similar catalytic performance without the drawbacks of high cost and catalyst distillation. The titanium compounds used have appropriate volatility characteristics that prevent excessive distillation during polycondensation.

The patent employs composite catalyst systems combining titanium compounds with phosphorous-containing stabilizers (such as phosphoric acid, phosphorous acid, or their esters). This composite approach allows the titanium to provide high polymerization activity while the phosphorous stabilizer protects against thermal degradation and coloration during subsequent melt molding processes.

The phosphorous-containing stabilizer acts as an intermediary protective agent between the titanium catalyst and the polyester chains. It mediates the thermal stress during processing, preventing the titanium-catalyzed polymerization from leading to thermal degradation and coloration during melt molding, thus decoupling the catalytic function from the thermal stability function.