. "These include polyvinyl alcohols, polyacrylamides, polyvinyl pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylates such as polyhydroxy ethyl acrylate, polyhydroxy methyl acrylate, polyhydroxy ethyl methacrylate, polyhydroxy methyl methacrylate and blends and copolymers thereof." . . . .