. . . "These copolymers may contain at least 50 mole%, preferably at least 80 mol%, based on the entire recurring units, of at least one acrylic monomer, and therefore may contain less than 50 moles%, preferably less than 20 mole%, based on the entire recurring units, of another monomer such as vinyl acetate, acrylonitrile, methacrylonitrile, styrene, vinyl pyrrolidone, vinylpyridine, itaconic acid or cr" . . .