Preparation of water-reducing copolymers for concrete

Abstract

Alkoxylated acrylate and methacrylate macromonomers are disclosed that are useful in the preparation of water-reducing additives for concrete, ultraviolet light-curable adhesives, and water-dispersed polyurethanes. The macromonomers are suitably prepared by alkoxylating a hydroxyalkylacrylate or hydroxyalkylmethacrylate in the presence of a DMC catalyst using the continuous addition of starter (CAOS) in order to prevent the formation of by-products during the fabrication of the macromonomer.

What is claimed is:  
     
         1 . An improved process for producing an alkoxylated acrylate macromonomer or an alkoxylated methacrylate macromonomer comprising reacting, at a reaction temperature of between about 60° C. and about 130° C., a first component selected from the group consisting of hydroxyalkylacrylate, hydroxyalkylmethacrylate, and combinations thereof, with a second component being an alkylene oxide compound, in the presence of a double metal cyanide (DMC) catalyst, and optionally in the presence of a solvent, wherein the first component is continuously added to a reactor containing at least some amount of said second component, and wherein the first component and the second component are co-fed co-currently or counter-currently into the reactor.  
     
     
         2 . The process of  claim 1  wherein said alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof.  
     
     
         3 . The process of  claim 1  wherein said catalyst is employed in an amount of between 5 ppm and 500 ppm, based upon the total amount of the reaction mixture.  
     
     
         4 . The process of  claim 1  wherein said catalyst is employed in an amount of between 15 ppm and 150 ppm, based upon the total amount of the reaction mixture.  
     
     
         5 . The process of  claim 1  wherein said reaction temperature is between about 60° C. and about 110° C.  
     
     
         6 . A process of producing a copolymer by reacting the macromonomer of  claim 1  with a monomer selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, styrene, maleic acid, methyl methacrylate, and combinations thereof at a reaction temperature of between about 0° C. and about 100° C.  
     
     
         7 . The process of  claim 6  wherein said reaction temperature is between about 30° C. and about 60° C.  
     
     
         8 . A process for making concrete using the copolymer of  claim 6  as a water reducing additive which comprises admixing cement, sand, water, and the copolymer in order to form the concrete, said water being present in an amount less than the amount necessary to form concrete in the absence of said copolymer.  
     
     
         9 . A process of producing water-dispersed polyurethane using the macromonomer of  claim 1  comprising the steps of: 
 (a) copolymerizing the macromonomer with an acid selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid, and combinations thereof, at a reaction temperature of between about 0° C. and about 100° C., to provide a copolymer containing hydroxyl moieties and acid moieties; and  
 (b) reacting at least a portion of said hydroxyl moieties on said copolymer with an isocyanate at an elevated temperature to produce a polyurethane containing at least a portion of said acid moieties situate in a middle, hydrophobic polyether, portion of said polyurethane in order to impart a water-dispersible characteristic to said polyurethane upon admixing said polyurethane with water.