Copolymers comprising low surface tension (meth)acrylates

Abstract

The present invention is directed to a copolymer that includes a first radically polymerizable low surface tension (meth)acrylate monomer and one or more other radically polymerizable ethylenically unsaturated monomers. The copolymer has a polydispersity index of less than 2.5. The present invention further includes a controlled radical polymerization method to make the above described low surface tension containing copolymers. The method includes the steps of adding a first radically polymerizable low surface tension (meth)acrylate monomer and one or more other radically polymerizable ethylenically unsaturated monomers to a solution containing a suitable atom transfer radical polymerization (ATRP) initiator.

1 . A thermosetting composition comprising:
 (a) A non-gelled polymer comprising functional monomers with a functional group;   (b) a crosslinking agent having at least two functional groups that are reactive with the functional groups of the non-gelled polymer in (a); and   (c) a copolymer flow control agent comprising a radically polymerizable low surface tension (meth)acrylate monomer and at least one other radically polymerizable ethylenically unsaturated monomer, wherein the radically polymerizable low surface tension (meth)acrylate monomer is selected from at least one low surface tension (meth)acrylate monomer represented by the general formulas:   
       
         
           
           
               
               
           
         
       
       wherein R 1  is selected independently for each general formula from hydrogen, methyl and ethyl, R 2  is selected independently for each general formula from the group consisting of linear, branched, cyclic, aryl and arylalkyl fluorinated hydrocarbon groups containing from 4-20 carbon, a siloxane, a polysiloxane, an alkyl siloxane, an ethoxylated trimethylsilyl siloxane and a propoxylated trimethylsilyl siloxane; Y is a divalent linking group containing from 1 to 20 carbon atoms, m is an integer from 1 to 4, and R 3  is a C 1 -C 4  alkyl group. 
     
     
         2 . The thermosetting composition of  claim 1  wherein m is 2. 
     
     
         3 . The thermosetting composition of  claim 1  wherein said copolymer flow additive is prepared by controlled radical polymerization. 
     
     
         4 . The thermosetting composition of  claim 1  wherein said radically polymerizable low surface tension (meth)acrylate monomer is present in an amount of from 0.01 percent by weight to 5.0 percent by weight, based on the total weight of said copolymer flow additive; and said at least one other radically polymerizable ethylenically unsaturated monomer is present in an amount of from 95 percent by weight to 99.99 percent by weight, based on the total weight of said copolymer flow additive. 
     
     
         5 . The thermosetting composition of  claim 1  wherein said at least one other radically polymerizable ethylenically unsaturated monomer is selected from vinyl monomers, allylic monomers, olefins and mixtures thereof. 
     
     
         6 . The thermosetting composition of  claim 1  wherein said copolymer flow additive has a number average molecular weight of from 500 to 100,000. 
     
     
         7 . The thermosetting composition of  claim 1  wherein R 1  is hydrogen or methyl, Y is —(CH 2 ) n —, and n is an integer from 1 to 11. 
     
     
         8 . The thermosetting composition of  claim 1  wherein said copolymer flow additive is present in an amount of from 0.01 percent by weight to 5 percent by weight, based on the total resin solids weight of said coating composition. 
     
     
         9 . The thermosetting composition of  claim 1 , wherein the functional groups of the non-gelled polymer (a) are selected from the group consisting of epoxy, oxirane, carboxylic acid, hydroxy, amide, oxazoline, aceto acetate, isocyanate, and carbamate; and the functional groups of crosslinking agent (b) are different than those in the non-gelled polymer (a), are reactable with those in the non-gelled polymer (a), and are selected from the group consisting of epoxy, oxirane, carboxylic acid, hydroxy, polyol, isocyanate, capped isocyanate, amine, aminoplast and beta-hydroxyalkylamide. 
     
     
         10 . The thermosetting composition of  claim 1  further comprising a third monomer wherein the copolymer flow control agent is a gradient copolymer defined by the structure:
   φ-{[-(M) s-a -(E) a - . . . -(M) s-na -(E) na -]-[L] m -T} z      
       wherein s is an integer from 1 to 300; a is an integer from 1 to 200; n is an integer from 1 to 299 such that s, n and a satisfy the relationship s-na≧0; M represents the other radically polymerizable ethylenically unsaturated monomers; L represents the radically polymerizable low surface tension (meth)acrylate monomer; φ is or is derived from the residue of the initiator free of radically transferable groups; T is or is derived from the radically transferable group of the initiator; and z is at least 1; E is a third polymerizable ethylenically unsaturated monomer; and m is an integer from 1 to 50. 
     
     
         11 . The thermosetting composition of  claim 1  wherein the copolymer flow control agent is defined by the structure:
   φ-[-(M) s-a (L) a -(M) s-2a -(L) 2a -(M) s-3a -(L) 3a - . . . -(M) s-na -(L) na -T] z      
       wherein s is an integer from 1 to 300, a is an integer from 1 to 10, n is an integer from 1 to 299 such that s, n and a satisfy the relationship s-na≧0, F represents a radically polymerizable low surface tension (meth)acrylate monomer, M represents at least one other radically polymerizable ethylenically unsaturated monomer, φ is or is derived from the residue of an atom transfer polymerization initiator free of radically transferable groups; T is or is derived from the radically transferable group of the initiator; z is at least 1 and the low surface tension (meth)acrylate monomer is one or more selected from the group consisting of those represented by the following general formulas, 
       
         
           
           
               
               
           
         
       
       wherein R 1  is selected independently for each general formula from hydrogen, methyl and ethyl, R 2  is selected independently for each general formula from the group consisting of linear, branched, cyclic, aryl and arylalkyl fluorinated hydrocarbon groups containing from 4-20 carbon, a siloxane, a polysiloxane, an alkyl siloxane, an ethoxylated trimethylsilyl siloxane and a propoxylated trimethylsilyl siloxane; Y is a divalent linking group containing from 1 to 20 carbon atoms, m is an integer from 1 to 4, and R 3  is a C 1 -C 4  alkyl group. 
     
     
         12 . The thermosetting composition  claim 11  wherein z is 1.