Associative acrylic thickening agent containing polyglycerols and its use to increase the open time of thin or thick films

Abstract

The present invention relates to new acrylic associative thickening agents which, when polymerized in the presence of particular polyglycerols, ultimately result in an increase of the open time of the paint or of the thick coating in which they are in incorporated. By so doing, painters and applicators will have more time to work the paint layers gradually or to correct imperfections such as paint droplets, and traces of brushes and filling-knives.

1 . A method for manufacturing an associative thickening agent comprising polymerizing, in an aqueous dispersion, in the presence of one or more surfactants other than polyglycerols of formula (I) below, the following monomers:
 a) at least one monomer which is (meth)acrylic acid,   b) at least one monomer which is an ester of (meth)acrylic acid, and   c) at least one monomer having a hydrophobic group,   
       in the presence of d) at least one polyglycerol of formula (I): 
       
         
           
           
               
               
           
         
       
       where R designates hydrogen, or an ester group functionalized by an alkyl group having 8 to 22 carbon atoms, or an alkyl group having 8 to 22 carbon atoms. 
     
     
         2 . A method according to  claim 1 , conducted as follows:
 introducing into water said at least one polyglycerol of formula (I) and the one or more surfactants other than polyglycerols of formula (I), followed by increasing the temperature of the medium, followed by introducing at least one polymerization initiator, and then monomers a), b) and c), optionally added in combination with additional water and additional surfactants other than polyglycerols of formula (I).   
     
     
         3 . A method according to  claim 1 , wherein the one or more surfactants other than polyglycerols of formula (I) are chosen from anionic surfactants, non-ionic surfactants, and blends of these surfactants. 
     
     
         4 . A method according to  claim 1 , wherein the mass % of the one or more surfactants other than polyglycerols of formula (I)/a)−d) is 1%-5%. 
     
     
         5 . A method according to  claim 1 , wherein the associative thickening agent is obtained by polymerizing, as a % by weight, relative to the total weight of the associative thickening agent:
 a) 20% to 60% by weight of at least one monomer which is (meth)acrylic acid,   b) 40% to 80% of at least one monomer which is an ester of (meth)acrylic acid, and   c) 0.5% to 25% of at least one monomer having a hydrophobic group, in the presence of   d) 0.1% to 10% by weight of at least one polyglycerol of formula (I)   
       where the sum of the percentages a), b), c) and d) is equal to 100%. 
     
     
         6 . A method according to  claim 1 , wherein the monomer containing at least one hydrophobic group has the general formula R—(OE) p -(OP) q —R′, where:
 m and n designate integers of less than or equal to 150, at least one of which is non-zero, 
 OE and OP designate respectively ethylene oxide and propylene oxide, 
 R designates a polymerizable group, 
 R′ designates a hydrophobic group having at least 6 and at most 36 carbon atoms. 
 
     
     
         7 . A method according to  claim 1 , wherein the associative thickening agent has an average molecular mass by weight of 20,000 g/mole-1,000,000 g/mole, as measured by GPC. 
     
     
         8 . A method according to  claim 3 , wherein the anionic surfactants are selected from the group consisting of sodium dodecyl sulphate, dioctyl sodium sulfosuccinate, sodium dodecylbenzenesulfonate, and mixtures thereof, and the non-ionic surfactants are selected from the group consisting of ethers of fatty alcohols and of polyoxyethylene glycol, esters of polyoxyethylene glycol, and mixtures thereof. 
     
     
         9 . A method according to  claim 1 , wherein a) is methacrylic acid and b) is ethyl acrylate. 
     
     
         10 . A polymeric associative thickening agent, which is the polymer obtained by the method according to  claim 1 . 
     
     
         11 . An aqueous formulation, comprising water and the polymeric associative thickening agent according to  claim 10 . 
     
     
         12 . The aqueous formulation according to  claim 11 , wherein the aqueous formulation is selected from the group consisting of a water-based paint, a roughcast paint and a render. 
     
     
         13 . A method, comprising adding the polymeric associative thickening agent of  claim 10  to another material or formulation.