Patent ID: 6642320
Filing Date: 2003-11-04
Classification: C04B,C08L

Abstract:
A multi-functional cement dispersant comprising graft copolymers obtained by;a first step of obtaining copolymers with average numerical molecular weight 3000-50000 by radical polymerization of a mixture of radical polymerizable monomers containing maleic anhydride and monomers of form given by Formula 1 below, together in an amount of 85 molar % or more of said mixture and at molar ratio of 50/50-80/20; and a second step of obtaining said graft copolymers by a graft reaction, in the presence of a basic catalyst, of 100 weight parts of said copolymers obtained in said first step and 3-35 weight parts of one or more selected from the group consisting of polyoxyalkylene monoalkylester, polyoxyalkylene monoalkylether and polypropylenglycol with repetition number of oxypropylene units equal to 3-15; CH2&boxH;CHâ€”CH2â€”Oâ€”Aâ€”Oâ€”Râ€ƒâ€ƒ(Formula 1) where R is acyl group with 1-18 carbon atoms, alkyl group with 1-3 carbon atoms or hydrogen, and A is a residual group obtained by removing all hydroxyl groups from polyalkylene glycol with repetition number of oxyalkylene units equal to 5-80, said oxyalkylene units consisting only of oxyethylene units or of both oxyethylene units and oxypropylene units; where said polyoxyalkylene monoalkylester has a block addition of a total of 2-10 moles of ethylene oxide and propylene oxide to one mole of aliphatic carboxylic acid with 1-6 carbon atoms; and where said polyoxyalkylene monoalkylether has a block addition of a total of 2-10 moles of ethylene oxide and propylene oxide to one mole of aliphatic alcohol with 1-6 carbon atoms.