Patent ID: 7147923

Claim:
A transparent multi-layer sheet, having light transmittance greater than 90%, comprising: a transparent flexible base layer formed of a substantially plasticizer-free polymeric material selected from the group consisting of ionomers, polyolefin homopolymers, polyolefin copolymers, block copolymers, fluorothermoplastics, polyurethanes, and combinations thereof; and first and second transparent flexible protective layers located on opposite sides of the base layer, each having a greater abrasion resistance than the transparent flexible base layer, and formed of a substantially plasticizer-freepolyurethane, the thickness of each protective layer being 50–130 micrometers; said transparent multi-layer sheet being sufficiently flexible to allow rolling it into a cylindrical shape without cracking or fracturing when it is tested according to ASTM test number D3 111-99 using a 6.4 mm mandrel at 250° C.