ALEXANDRIA, Va., Sept. 23 -- United States Patent no. 12,421,387, issued on Sept. 23, was assigned to UNITIKA Ltd. (Hyogo, Japan).
"Polyester film and method for producing same" was invented by Takayoshi Okuzu (Kyoto, Japan), Ken Akamatsu (Kyoto, Japan), Akiko Hamamoto (Kyoto, Japan), Hiroshi Ashihara (Kyoto, Japan), Goro Araki (Kyoto, Japan) and Akito Kajita (Kyoto, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A polyester film comprises a polyester (A) composed mainly of polybutylene terephthalate and a polyester (B) composed mainly of polyethylene terephthalate, wherein a mass ratio (A/B) between the polyesters (A) and (B) is 70/30 to 55/45, a dry heat shrinkage rate (A) through heat treatment at 1...