Patent ID: 6894121
Filing Date: 2005-05-17
Classification: C04B,C07C

Abstract:
1. A cement dispersant comprising graft copolymers and/or salts thereof obtained by a first process, a second process and a third process; said first process being wherein an esterification reaction is carried out with α-allyl-ω-hydroxy-polyoxyalkylene shown by Formula 1, refined so as to have a peroxide value less than 5.0 meq/kg, and aliphatic monocarboxylic acid shown by Formula 2, in the absence of any solvent and in the presence of antioxidant and under a heated and reduced-pressure condition by using an acid catalyst and distilling away generated water: where R is alkyl group with 1-6 carbon atoms and A is residual group obtained by removing all hydroxyl groups from polyallcyleneglycol of which the repetition number of oxyalkylene units, consisting either only of oxyethylene units or of both oxyethylene units and oxypropylene units, is 2-250; said second process being wherein vinyl copolymers are obtained by a radical copolymerization reaction of the allyletherester monomer obtained in said first process and maleic anhydride; and said third process being wherein graft copolymers are obtained by a graft reaction of the vinyl copolymers obtained in said second process and polyoxyalkylene monoalkylether and/or polyoxyalkylene monoalkylester.