"The substrate may be any material of the requisite structural integrity but is commonly a metal or a polymer such as polyurethane, vinyl resin as exemplified by polyvinyl chloride, a polyacrylate, such as polymethylmethacrylate, a polycarbonate, a polyester such as polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate as well as various rubbery polymers such as p" . . . . .