The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 2020
Filed:
Mar. 23, 2018
Dak Americas Llc, Charlotte, NC (US);
Helen J. Codd, Wilmington, NC (US);
George F. Rollend, Amherst, NH (US);
Norman W. Lisson, Mount Pleasant, SC (US);
DAK AMERICAS LLC, Charlotte, NC (US);
Abstract
A method for producing ultra-high intrinsic viscosity (IV) polyester resin pellets from a resin that contains one or more comonomers in an amount of up to 30 mol%. The method includes extruding a polyethylene terephthalate polyester starting material having a starting IV (IVst) meeting the following relationship: 0.65 dL/g <IVst <0.9 dL/g, to form resin particles having no more than 0.05 dL/g of IV lift due to solid-state polymerization, then latent heat crystallizing the resin particles to form crystallized particles having a variation of IV of no more than 0.05 dL/g across any dimension of the crystallized particles. The crystallized particles are then solid state polymerized to a final IV (IVf) of at least 0.9 dL/g to form the ultra-high intrinsic viscosity (IV) polyester resin pellets. During the solid state polymerizing the IV lift rate is at least 0.012 dL/g/hr.