Abstract: A multilayer sunlight dosage indicator comprising (a) an indicator layer comprising a sunlight-sensitive ink, wherein the ink undergoes a color change upon exposure to a known amount of sunlight; and (b) an overlayer comprising an amount of at least one UV absorber. A method for indicating the amount of exposure to sunlight using an indicator layer of sunlight-sensitive ink which undergoes a color change upon exposure to a known amount of sunlight and an overlayer comprising an amount of at least one UV absorber. It is possible to adjust the sensitivity of the indicator by controlling the UV absorbing materials in the overlayer.
Type:
Grant
Filed:
February 27, 2001
Date of Patent:
May 11, 2004
Assignee:
Questel Adhesives
Inventors:
John M. Questel, Christian D. Sololowski