Patent ID: 6482502
Filing Date: 2002-11-19
Classification: B29C,C09K,Y10T

Abstract:
An optical quality plastic sheet having a thickness of 25 mm or less with a thickness variation over a 400 mm length of 10% or less, shrinkage of &lE;0.05%, a waviness value Wy&lE;1.0&mgr; and a roughness value Rq&lE;50 nm wherein the plastic sheet has a birefringence of 0.0002 or less and wherein the plastic sheet comprises a thermoplastic resin selected from the group consisting of: homopolymers or copolymers of acrylic acid, methacrylic acid and their esters; phenoxy ethers; polyphenylene oxide resins, epoxy resins; cellulosic resins; vinyl polymers; fluoropolymers; polycarbonates; polystyrenes; polyolefins; polysulfones; polyether sulfones; polyether ketones; polyether imides, polyphenylene sulfides; polyarylene ester resins; polyesters; homopolymers or copolymers of Nâ€”H and/or N-alkyl glutarimide; acrylonitrile-butadiene-styrene resins; styrene-acrylonitrile resins; styrene-maleic anhydride resins; imidized styrene-maleic anhydride; polyamides; and mixtures thereof.