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. 05, 1988
Filed:
Mar. 09, 1987
Tzu L Huang, Woodbury, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
Retroreflective sheeting has been improved by a coating comprising silica and a transparent polymer selected from aliphatic polyurethanes and polyvinyl chloride copolymers having a minor amount of a comonomer containing at least one carboxylic acid or hydroxyl moiety. Silica comprises 10-80 weight percent of the transparent protective coating. For example, a solution or dispersion of polyurethane is mixed with a silica sol and possibly other ingredients (e.g. wetting agent, UV light absorber and adhesion promoter), and the composition is coated onto the retroreflective sheet and dried. The coated retroreflective sheeting has superior soil and dew repellancy, retaining a higher percentage of original brightness after exposure to dirt and/or dew conditions.