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:
Jul. 16, 2002
Filed:
Jul. 12, 2000
Martin L. Hage, Maple Grove, MN (US);
Edward A. Travnicek, Ramsey, MN (US);
Vision - Ease Lens, Inc., Minneapolis, MN (US);
Abstract
The removal of certain reaction impurities in the manufacture of polysulfone polymers has been found to reduce the undesirable coloration in the final resin. Control of synthesizing reactions, manufacturing processes, and/or purification of specific ingredients assists in the removal of specific, undesirable impurities. The yellowness index, as determined by ASTM D1925 or ASTM E313, in the commercial grades of polysulfone resins has consistently been well above 1.0 for commercial polysulfone resins. The present invention provides polysulfone polymers after processing (e.g., injection molding) where the yellowness index is below 1.00, below 0.75, below 0.50, and even below 0.25.