Retroreflective security laminates with protective cover sheets

Claim 1

A legend-containing, substantially transparent laminate which is retroreflective over substantially its entire surface area, said laminate having retroreflective legend areas and retroreflective background areas, which areas are substantially transparent and substantially indistinguishable under ordinary diffuse light viewing conditions, said legend areas and said background areas having visually distinguishable retroreflective properties whereby said legend areas are readily discernible from said background areas under retroreflectivelight viewing conditions, wherein said laminate comprises: (a) a base sheet comprising microspheres arranged in substantially a monolayer with partially-light-transmissive reflectors disposed behind the rear surfaces thereof, said microspheres being at least partially embedded in a transparent binder layer, said base sheet further comprising lacquer disposed behind the rear surfaces of some of said microspheres; and (b) a cover sheet bonded to the front side of said base sheet, said cover sheet comprising an outer layer having an abrasion-resistant outer surface and a support layer on the inner surface of said outer layer, said outer surface suffering an increase in percent haze of less than about 20 percent when subjected to 100 abrasion cycles in accordance with ASTM D-1044-85, said support layer being resistant to deformation under localized pressure and characterized in that it has a thickness of at least about 25 microns and has a Knoop Hardness of at least about 10.