Polymer particles and coating compositions formulated from the polymer particles

Abstract

The invention provides polymer particles useful in a variety of applications, including coating applications such as packaging coatings. The polymer particles preferably have a volume-averaged particle size of less than 40 microns, more preferably less than 20 microns. In preferred embodiments, the polymer particles are precipitated particles, more preferably precipitated polyester particles, which are optionally free of low-molecular weight surfactant.

1 .- 25 . (canceled) 
     
     
         26 . A powder coating composition for coating metal substrates, the coating composition comprising precipitated polymer particles having a volume-averaged particle size of less than 20 microns; wherein the coating composition is substantially free of bisphenol A, and aromatic glycidyl ether compounds. 
     
     
         27 . The powder coating composition of  claim 26 , wherein the polymer particles are essentially completely free of bisphenol A, and aromatic glycidyl ether compounds. 
     
     
         28 . The powder coating composition of  claim 26 , wherein the polymer particles are completely free of bisphenol A, and aromatic glycidyl ether compounds. 
     
     
         29 . The powder coating composition of  claim 26 , wherein the polymer particles have a volume-averaged particle size of less than 10 microns. 
     
     
         30 . The powder coating composition of  claim 26 , wherein the polymer particles have a volume-averaged particle size of greater than 3 microns. 
     
     
         31 . The powder coating composition of  claim 26 , wherein the polymer particles comprise a thermoplastic or thermoset polymer. 
     
     
         32 . The powder coating composition of  claim 26 , wherein the polymer particles comprise a polymer having a melting point of at least about 40° C. 
     
     
         33 . The powder coating composition of  claim 26 , wherein the polymer particles comprise a polymer having a melting point of less than about 260° C. 
     
     
         34 . The powder coating composition of  claim 26 , wherein the polymer particles comprise a polymer selected from an acrylic, a polyamide, a polyurethane, a polyester, and a combination thereof. 
     
     
         35 . The powder coating composition of  claim 26  further comprising one or more additives selected from a wax, a lubricant, a crosslinker, a cure catalyst, a pigment, and a combination thereof. 
     
     
         36 . The powder coating composition of  claim 35  further comprising a lubricant. 
     
     
         37 . The powder coating composition of  claim 26 , wherein the polymer particles are spherical. 
     
     
         38 . A powder coating composition for coating metal substrates, the coating composition comprising polymer particles having a volume-averaged particle size of less than 20 microns, and a lubricant; wherein the coating composition is substantially free of bisphenol A, and aromatic glycidyl ether compounds. 
     
     
         39 . The powder coating composition of  claim 38 , wherein the polymer particles are spherical. 
     
     
         40 . The powder coating composition of  claim 38 , wherein the polymer particles have a volume-averaged particle size of less than 10 microns. 
     
     
         41 . The powder coating composition of  claim 38 , wherein the polymer particles comprise a thermoplastic or thermoset polymer. 
     
     
         42 . The powder coating composition of  claim 38 , wherein the polymer particles comprise a polymer selected from an acrylic, a polyamide, a polyurethane, a polyester, and a combination thereof. 
     
     
         43 . The powder coating composition of  claim 38  further comprising one or more additives selected from a wax, a crosslinker, a cure catalyst, a pigment, and a combination thereof. 
     
     
         44 . A coating composition prepared by a process comprising the steps of:
 (a) preparing a mixture of an organic solvent and a solid crystallizable polymer;   (b) heating the mixture to a temperature sufficient to dissolve, but not melt, the solid crystallizable polymer in the organic solvent; and   (c) cooling the mixture to form precipitated polymer particles having a volume-averaged particle size of less than 20 microns;   the resulting coating composition being substantially free of bisphenol A, and aromatic glycidyl ether compounds.   
     
     
         45 . A coating composition suitable for use as a film-forming binder of a thermally cured interior food-contact or beverage can, the coating composition resulting from the precipitation of a solid crystallizable polymer from an organic solvent;
 the resulting coating composition being substantially free from bisphenol A and aromatic glycidyl ether compounds and characterized by a volume-averaged polymer particle size of less than 20 microns.