Process for producing hyperbranched polymers

Abstract

A method is provided for producing hyperbranched polymers comprising heating a polymerizable reaction charge comprising (a) a monomer mixture comprising 50-99.1% by weight of at least one monoethylenically unsaturated monomer and 0.1-50% by weight of one or more multiethylenically unsaturated monomers and (b) if at least one ethylenically unsaturated monomer of the monomer mixture is not a thermally initiating monomer, a free radical polymerization initiator, to a temperature in the range from about 250° C. to about 400° C. in a continuous reactor which allows mixing of the reactor contents for a residence time of from about 2 minutes to about 60 minutes, provided that if the total amount of multiethylenically unsaturated monomer is less than 3% by weight of the monomer mixture than at least one of said one or more multiethylenically unsaturated monomers must be tri- or greater ethylenically unsaturated. The hyperbranched polymers prepared by this process are also described.

What is claimed is:  
     
         1 . A method for producing hyperbranched polymers, said method comprising the step of heating a polymerizable reaction charge comprising (a) a monomer mixture comprising (i) at least one monoethylenically unsaturated monomer in an amount of about 50-99.9% by weight of the monomer mixture and (ii) one or more multiethylenically unsaturated monomers in an amount of about 0.1-50% by weight of the monomer mixture, and (b) if at least one ethylenically unsaturated monomer of said monomer mixture is not a thermally initiating monomer, a free radical polymerization initiator, to a temperature in the range from about 250° C. to about 400° C. in a continuous reactor which allows mixing of the reactor contents for a residence time of from about 2 minutes to about 60 minutes, provided that if the total amount of multiethylenically unsaturated monomer is less than 3% by weight of the monomer mixture then at least one of said one or more multiethylenically unsaturated monomers must be tri- or greater ethylenically unsaturated.  
     
     
         2 . The method of  claim 1 , wherein the multiethylenically unsaturated monomer is selected from the group consisting of diethylenically unsaturated monomers, triethylenically unsaturated monomers, tetraethylenically unsaturated monomers and mixtures thereof.  
     
     
         3 . The method of  claim 2 , wherein the temperature is in the range from about 300° C. to about 350° C.  
     
     
         4 . The method of  claim 3 , wherein the continuous reactor is a continuous stirred tank reactor or a continuous loop reactor.  
     
     
         5 . The method of  claim 4 , wherein the multiethylenically unsaturated monomer is divinylbenzene.  
     
     
         6 . The method of  claim 5 , wherein the monoethylenically unsaturated monomer is styrene or a mixture of styrene and another monoethylenically unsaturated monomer.  
     
     
         7 . The method of  claim 6 , wherein the other monoethylenically unsaturated monomer is selected from the group consisting of α-methylstyrene, acrylic acid, methacrylic acid, methyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate.  
     
     
         8 . The method of  claim 7 , wherein the divinylbenzene is present in the monomer mixture in an amount in the range from about 10% by weight to about 15% by weight of the polymer.  
     
     
         9 . The method of  claim 8 , wherein the residence time is from about 10 minutes to about 20 minutes.  
     
     
         10 . The method of  claim 9 , wherein the reactor is substantially filled.  
     
     
         11 . A hyperbranched polymer produced by the method comprising the step of heating a polymerizable reaction charge comprising (a) a monomer mixture comprising (i) at least one monoethylenically unsaturated monomer in an amount of 50-99.1% by weight of the monomer mixture and (ii) one or more multiethylenically unsaturated monomers in an amount of about 0.1-50% by weight of the monomer mixture, and (b) if at least one ethylenically unsaturated monomer mixture is not a thermally initiating monomer, a free radical polymerization initiator, to a temperature in the range from about 250° C. to about 400° C. in a continuous reactor which allows mixing of the reactor contents for a residence time of from about 2 minutes to about 60 minutes, provided that if the total amount of multiethylenically unsaturated monomer is less than 3% by weight of the monomer mixture then at least one of said one or more multiethylenically unsaturated monomers must be tri- or greater ethylenically unsaturated.  
     
     
         12 . The hyperbranched polymer of  claim 11 , wherein the multiethylenically unsaturated monomer is selected from the group consisting of diethylenically unsaturated monomers, triethylenically unsaturated monomers, tetraethylenically unsaturated monomers and mixtures thereof.  
     
     
         13 . The hyperbranched polymer of  claim 12 , wherein the temperature is in the range from about 300° C. to about 350° C.  
     
     
         14 . The hyperbranched polymer of  claim 13 , wherein the continuous reactor is a continuous stirred tank reactor or a continuous loop reactor.  
     
     
         15 . The hyperbranched polymer of  claim 14 , wherein the multiethylenically unsaturated monomer is divinylbenzene.  
     
     
         16 . The hyperbranched polymer of  claim 15 , wherein the monoethylenically unsaturated monomer is styrene or a mixture of styrene and another monoethylenically unsaturated monomer.  
     
     
         17 . The hyperbranched polymer of  claim 16 , wherein the other monoethylenically unsaturated monomer is selected from the group consisting of α-methylstyrene, acrylic acid, methacrylic acid, methyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate.  
     
     
         18 . The hyperbranched polymer of  claim 17 , wherein the divinylbenzene is present in the monomer mixture in an amount in the range from about 10% by weight to about 15% by weight of the polymer.  
     
     
         19 . The hyperbranched polymer of  claim 18 , wherein the residence time is from about 10 minutes to about 20 minutes.  
     
     
         20 . The hyperbranched polymer of  claim 19 , wherein the reactor is substantially filled.  
     
     
         21 . A hyperbranched polymer comprising at least about 3% by weight of repeat units derived from divinylic monomers, about 50 to about 97% by weight of repeat units derived from monoethylenically unsaturated monomers and having a polydispersity of less than about 20.  
     
     
         22 . The hyperbranched polymer of  claim 19  with at least 6% by weight of repeat units derived from divinylic monomers.