Acrylic powder coating resin having low volatility

Abstract

Powder coating compositions having reduced volatility and improved processibility compared to conventional powder coatings consist essentially of a copolymer having pendant functionalities or pendant groups capable of reacting with a dicarboxylic acid such as the glycidyl groups of glycidyl acrylate or methacrylate copolymer and a cross-linking effective amount of a dicarboxylic acid. The reaction of the above pendant groups and the dicarboxylic acid cross-links or cures the powder coating after application to a substrate. The dicarboxylic acids according to the invention eliminate the need for a third component which is a flow control agent which improves the processibility of a two-component powder coating. The dicarboxylic acids according to the invention have a sublimation temperature great enough to decrease or prevent their vaporization during the curing of the powder coating and have a melting point low enough to impart improved flow properties to the powder coatings.

What is claimed is:  
     
         1 . A composition consisting essentially of a copolymer having a pendant functionality capable of reacting with a dicarboxylic acid and a cross-linking effective amount of a dicarboxylic acid having at least 14 carbon atoms.  
     
     
         2 . The composition of  claim 1  wherein the dicarboxylic acid is a saturated dicarboxylic acid.  
     
     
         3 . The composition of  claim 1  wherein the dicarboxylic acid has from about 14 to about 20 carbon atoms.  
     
     
         4 . The composition of  claim 2  wherein the dicarboxylic acid is octadecanedioic acid.  
     
     
         5 . The composition of  claim 1  wherein the copolymer is a glycidyl methacrylate or a glycidyl acrylate copolymer.  
     
     
         6 . The composition of claim I wherein the effective amount of the dicarboxylic acid is from about 2% to about 50% by weight.  
     
     
         7 . A composition consisting essentially of a copolymer having glycidyl pendant groups and a cross-linking effective amount of octadecanedioic acid.  
     
     
         8 . A composition on consisting essentially of a glycidyl methacrylate and an effective amount of octadecanedioic acid.  
     
     
         9 . A composition consisting essentially of a glycidyl methacrylate and from about 2% to about 50% by weight of octadecanedioic acid.