2-Propenoic acid, 2-methyl-, polymer with butyl 2-propenoate, N-(hydroxymethyl)-2-methyl-2-propenamide, methyl 2-methyl-2-propenoate and 2-methyl-2-propenamide Polymer of butyl acrylate, methylol methacrylamide, methacrylamide, methyl methacrylate and methacrylic acid