Cement additives
AssigneeArco Chemical Technology, L.P.
InventorEdward T. Shawl
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Abstract
Substances useful as water reducing and superplasticizer additives for cement compositions are formed by reaction of carboxylic acid polymers with a mixture of monofunctional and difunctional polyethers derived from C.sub.2 -C.sub.4 epoxides wherein partial cleavage of the polyethers and esterification of the polyethers 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), a monofunctional ethylene oxide-propylene oxide copolymer, and a difunctional poly(propylene glycol), at a temperature in excess of 140.degree. C.
Claims21
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 mixture comprising (i) a monofunctional polyether prepared by polymerizing a first epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof onto a monofunctional initiator and (ii) a difunctional polyether prepared by polymerizing a second epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof, which may be the same as or different from the first epoxide, onto a difunctional initiator, wherein (a) and (b) are reacted under conditions effective to achieve partial cleavage of the polyether mixture and esterification of the polyether mixture and cleavage products thereof by the carboxylic acid polymer.
A cement additive containing carboxylic acid groups prepared by reaction of (a) a carboxylic acid polymer prepared by polymerizing acrylic acid and (b) a polyether mixture comprising (i) a monofunctional polyether prepared by polymerizing a first epoxide selected from the group consisting of ethylene oxide, propylene oxide and mixtures thereof onto a monoalcohol initiator and (ii) a difunctional polyether prepared by polymerizing a second epoxide selected from the group consisting of ethylene oxide, propylene oxide and mixtures thereof, which may be the same as or different from the first epoxide, onto a di-alcohol initiator, wherein (a) and (b) are reacted in the presence of an acid catalyst having a pKa of less than 0 under conditions effective to achieve partial cleavage of the polyether mixture and esterification of the polyether mixture and cleavage products thereof by the carboxylic acid polymer.
A cement composition comprised of cement and from 0.05 to 2% by weight, based on the dry weight of cement, of a cement additive containing carboxylic acid groups produced by a 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 mixture comprising (i) a monofunctional polyether prepared by polymerizing a first epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof, onto a monofunctional initiator and (ii) a difunctional polyether prepared by polymerizing a second epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof, which may be the same as or different from the first epoxide, onto a di-functional initiator, wherein (a) and (b) are reacted under conditions effective to achieve partial cleavage of the polyether mixture and esterification of the polyether mixture and cleavage products thereof by the carboxylic acid polymer.
A method of preparing 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 mixture comprising
- (i) a monofunctional polyether prepared by polymerizing a first epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof onto a monofunctional initiator;
- and
- (ii) a difunctional polyether prepared by polymerizing a second epoxide selected from the group consisting of C.sub.2 -C.sub.4 epoxides and mixtures thereof, which may be the same as or different from the first epoxide, onto a difunctional initiator;
- in the presence of an acid catalyst having a pKa of less than 0 at a temperature effective to achieve partial cleavage of the polyether mixture and esterification of the polyether mixture and cleavage products thereof by the carboxylic acid polymer.
Dependencies are inferred from the claim text.