Cement additives
AssigneeArco Chemical Technology, L.P.
InventorEdward T. Shawl
Life of this patent
Estimating the term…
Abstract
Substances useful as water reducing and superplasticizer additives for cement compositions are formed by reaction of carboxylic acid polymers with polyethers of C.sub.2 -C.sub.4 epoxides wherein partial cleavage of the polyether and esterification of the polyether and the cleavage products thereof by the other reactant are achieved. In one embodiment, a sulfonic acid is used to catalyze the reaction of poly(acrylic acid) and a monofunctional ethylene oxide-propylene oxide copolymer at a temperature in excess of 140.degree. C.
Claims24
A cement additive containing carboxylic acid groups produced by reaction of (a) a carboxylic acid polymer prepared by polymerizing a polymerizable acid monomer containing at least one ethylenically unsaturated group in conjugation with a carboxyl group selected from the group consisting of carboxylic acid, carboxylic anhydride and carboxylic ester groups and (b) a polyether prepared by polymerizing a C.sub.2 -C.sub.4 epoxide, wherein (a) and (b) are reacted under conditions effective to achieve partial cleavage of the polyether and esterification of the polyether and cleavage products thereof by the carboxylic acid polymer.
A cement additive containing carboxylic acid groups produced by reaction of (a) a carboxylic acid polymer selected from the group consisting of polyacrylic acid and poly(maleic acid-co-acrylic acid) and (b) a monofunctional ethylene oxide-propylene oxide copolymer having a number average molecular weight of from 200 to 10,000, wherein (a) and (b) are reacted under conditions effective to achieve partial cleavage of the polyether and esterification of the polyether and cleavage products thereof by the carboxylic acid polymer.
A method for producing a cement additive containing carboxylic acid groups comprising reacting (a) a carboxylic acid polymer prepared by polymerizing a polymerizable acid monomer containing at least one ethylenically unsaturated group in conjugation with a carboxyl group selected from the group consisting of carboxylic acid, carboxylic anhydride, and carboxylic ester groups and (b) a polyether prepared by reacting a C.sub.2 -C.sub.4 epoxide, said reacting of (a) and (b) being performed in the presence of a protic acid catalyst having a pKa of less than 0 for a time and at a temperature effective to achieve partial cleavage of the polyether and esterification of the polyether and cleavage products thereof by the carboxylic acid polymer to form the cement additive.
Dependencies are inferred from the claim text.