Patent ID: 7879279

Claim:
An injection molding method for polyethylene terephthalate, comprising: subjecting terephthalic acid, silicon oxide nanoparticles, and ethylene glycol to esterification to form a bis(2-hydroxyethyl) terephthalate monomer and a nucleating agent of polyethylene terephthalate, comprising: a silicon oxide core, and a plurality of bis(2-hydroxyethyl) terephthalate oligomers grafted on the surface of the silicon oxide core, said nucleating agent having the formula: wherein n is an integer larger than 1, polymerizing the bis(2-hydroxyethyl) terephthalate monomer to form the polyethylene terephthalate, wherein the polyethylene terephthalate and the bis(2-hydroxyethyl) terephthalate oligomers proceed an in-situ polymerization; blending additives with the polyethylene terephthalate by an extruder and processing the blend into pellets, melting the pellets and injecting the melt into a mold, and cooling the mold to form an article.