| abstract |
Copolymers having the formula <IMAGE> where B represents Na, K, NH4, <IMAGE> or 2-amino-2-methylpropanol-1, R1 and R2 represent hydrogen or -(X) OH; X represents an alkylene having 1-3 carbon atoms or alkylene substituted by at least one hydroxy methyl, M represents at least one unsaturated monomer selected from acrylamides or methacrylamides substituted on the nitrogen by alkyl, the acrylates or methacrylates of monoalkyl ether of ethylene glycol or of polyethylene glycol, and N-vinylpyrrolidone, x is 22-64 mole percent, y is 13-71 mole percent, z is 6-23 mole percent, v is 0-22 mole percent and x+y+z+v is equal to 100 mole percent, can be produced by copolymerizing N,N-dimethylamino-2 ethyl methacrylate, methyl methacrylate, methacrylic acid and optionally at least one other monomer corresponding to M. |