Process for preparing polyacrylates

Abstract

Use of amino acids as regulator substances in the free-radical polymerization of monomer mixtures comprising at least 70% by weight of at least one acrylic and/or methacrylic ester and reaction solution comprising one or more solvents and one or more monomers, at least 50% by weight of the solvents being organic solvents, and at least 70% by weight of the monomers being acrylic and/or methacrylic esters, with at least one amino acid is being present.

1 . Reaction solution comprising one or more solvents and one or more monomers, at least 50% by weight of the solvents being organic solvents, and at least 70% by weight of the monomers being acrylic and/or methacrylic esters,
 wherein   at least one amino acid is additionally present.   
     
     
         2 . Reaction solution according to  claim 1 , wherein at least 90% by weight of the solvents are organic solvents. 
     
     
         3 . Reaction solution according to  claim 1 , wherein the reaction solution is a homogeneous solution. 
     
     
         4 . Reaction solution according to  claim 1 , wherein the at least one amino acid has at least one sulphanyl, selanyl and/or hydroxyl group. 
     
     
         5 . Reaction solution according to  claim 4 , wherein the at least one sulphanyl, selanyl and/or hydroxyl group is terminal. 
     
     
         6 . Reaction solution according to  claim 1 , wherein said at least one amino acid is at least one amino acid of a natural or non-natural α-amino acid of the following structural formula 
       
         
           
           
               
               
           
         
         where R 1 , R 2  and R 3  are selected independently of one another, with R 1  selected from the group (i), consisting of 
         (i) linear and branched C 1  to C 18  alkyl radicals, linear and branched C 2  to C 18  alkenyl radicals, linear and branched C 2  to C 18  alkynyl radicals, aryl radicals, cycloaliphatic, aliphatic and aromatic heterocycles, and hydrogen,
 and R 2  and R 3  are selected from the group consisting of group (i) or are selected from the from group consisting of group (ii), 
 
         (ii) acyl radicals, (—C(O)—R′), alkoxycarbonyl radicals (—C(O)—O—R′), carbamoyl radicals (—C(O)—NR′R″), and sulphonyl radicals (—SO 2 R′),
 where R′ and R″ are radicals from group i) that are selected independently of one another, and 
 
         X is oxygen (O), sulphur (S) or selenium (Se), 
         and n is a natural number including zero. 
       
     
     
         7 . Reaction solution according to  claim 6 , wherein n is in the range of 0≦n≦18. 
     
     
         8 . Reaction solution according to  claim 1 , wherein the acrylic and/or methacrylic ester or esters satisfy the formula 
       
         
           
           
               
               
           
         
       
       where 
       R 1 =H or CH 3    
       and 
       R 2 =H or an unbranched or branched, aliphatic, alicyclic or aromatic, unsubstituted or substituted hydrocarbon radical having 1 to 20 carbon atoms without C═C double bonds. 
     
     
         9 . A polyacrylate obtained from a reaction solution of  claim 1  by free-radical polymerization of the monomers present therein. 
     
     
         10 . Process for preparing a polyacrylate from the reaction solution of  claim 1  by free-radical polymerization, wherein the solvent is removed from the polymerization product after the polymerization down to a residual solvent amount of not more than 2% by weight. 
     
     
         11 . Process according to  claim 10 , wherein the amino acid or acids remain in the polymerization product when the solvent is removed. 
     
     
         12 . Process according to  claim 10  wherein the solvent removed is supplied to a recycling operation. 
     
     
         13 . Process according to  claim 10 , wherein at least one of the organic solvents used is obtained from a recycling operation. 
     
     
         14 . A process comprising the free-radical polymerization of monomer mixtures comprising at least 70% by weight of at least one acrylic and/or methacrylic ester wherein amino acids are present as regulator substances.