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:
Mar. 27, 2001
Filed:
Dec. 11, 1997
Casmir Stanislaus Ilenda, Holland, PA (US);
Phelps Brian Johnson, Wauwatosa, WI (US);
Michael Paul Hallden-Abberton, Maple Glen, PA (US);
Fiberstors Incorporated, Solon, OH (US);
Abstract
Acrylic light pipe has adequate thermal and photo-thermal stability for many purposes, but is deficient in maintaining clarity, color, and good optical properties under conditions of exposure to high temperatures, especially in combination with exposure for lengthy periods to passage of light. Improved thermal stability, as reflected in reduced color formation, can be imparted by adjusting the polymerization conditions to produce the uncured core polymer of the core/clad construction with a much reduced terminal vinyl content, preferably below 0.5 vinyl groups/1000 monomer units. This process improvement, in combination with selected addition of a combination of certain hindered phenols and hydrolytically stable organic phosphites, together produce a substantial improvement in the resistance to discoloration under photo-thermal conditions, while maintaining the resistance to discoloration under thermal conditions. The known process conditions which do not yield lower terminal vinyl content, in combination with the selected additives, also produce acrylic light pipe with greatly improved photo-thermal stability.