Copolymers useful as cement additives and a process for their preparation
AssigneeArco Chemical Technology, L.P.
InventorsKenneth G. McDaniel, Edward T. Shawl, Xinhau Zhou
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Abstract
Unique, well defined macromonomers containing hydroxyl-functionality, unsaturation-functionality, and polyoxyalkylene segments are prepared by oxyalkylating an unsaturated initiator molecule having at least one oxyalkylatable hydrogen in the presence of an effective amount of a double metal cyanide complex catalyst, optionally, when necessary, in the presence of a free radical polymerization inhibitor. The resulting unsaturated macromonomers are eminently suitable for such uses as copolymerization with ethylenically unsaturated monomers containing carboxylic acid-based groups such as acrylic acid to form effective superplasticizers and water reducers for cement and concrete applications.
Claims18
A copolymer useful as a cement additive obtained by
- (a) oxyalkylating an initiator molecule selected from the group consisting of hydroxyalkyl acrylates, hydroxyalkyl methacrylates, and monounsaturated monocarboxylic acids with an alkylene oxide in the presence of an effective amount of a double metal cyanide complex catalyst under conditions effective to form a well-defined unsaturated macromonomer having a terminal hydroxyl functionality and not more than substantially one initiator molecule per unsaturated macromonomer molecule;
- and
- (b) copolymerizing the unsaturated macromonomer with at least one comonomer which is ethylenically unsaturated and has at least one carboxylic acid-based group selected from free carboxylic acids, carboxylic acid salts, hydroxyalkyl esters of carboxylic acids, and carboxylic acid anhydrides.
A process for preparing a copolymer useful as a cement additive comprising the steps of
- (a) oxyalkylating an initiator molecule selected from the group consisting of hydroxyalkyl acrylates, hydroxyalkyl methacrylates, and monounsaturated monocarboxylic acids with an alkylene oxide in the presence of a double metal cyanide complex catalyst under conditions effective to form a well-defined unsaturated macromonomer having a terminal hydroxyl functionality and not more than substantially one initiator molecule per unsaturated macromonomer molecule;
- and
- (b) copolymerizing the well-defined unsaturated macromonomer with at least one comonomer which is ethylenically unsaturated and has at least one carboxylic acid-based group selected from free carboxylic acids, carboxylic acid salts, hydroxyalkylesters of carboxylic acids, and carboxylic acid anhydrides.
Dependencies are inferred from the claim text.