Crosslinkable polyester-polyurethane coating composition for packaging containers

Abstract

The present invention provides a coating composition having crosslinkable polyester-polyurethane polymer with at least two carbamate sites, and a crosslinker usable for coating a packaging container. The coating composition may be applied to a generally planar substrate, cured and formed into a container or a portion of a container. The present invention also provides a coated substrate having the coating composition.

What is claimed is:  
     
         1 . A coating composition, comprising: 
 a crosslinkable polyester-polyurethane polymer having at least two carbamate sites;    a crosslinker; and    at least one adjuvant selected from the group consisting of carriers, lubricants, pigments, rheological control agents, and flow control agents.    
     
     
         2 . The coating composition of  claim 1 , wherein the crosslinkable polyester-polyurethane polymer is formed from the reaction of a hydroxy functional polyester intermediate and a polyisocyanate compound.  
     
     
         3 . The coating composition of  claim 2 , wherein the hydroxy functional polyester intermediate is a reaction product of a diol having between 2 and 12 carbon atoms and a dicarboxylic acid having between 4 and 40 carbon atoms.  
     
     
         4 . The coating composition of  claim 3 , wherein the diol is selected from the group consisting of butane diol, butyl ethyl propane diol, 2-methyl 1,3-propane diol, 1,3-propane diol, hexane diol, cyclohexane dimethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, and hydroxypivalyl hydroxypivalate.  
     
     
         5 . The coating composition of  claim 3 , wherein the dicarboxylic acid is selected from the group consisting of adipic acid, azelaic acid, sebacic acid, naphthalene dicarboxylic acid, dodecane dicarboxylic acid, cyclohexane dicarboxylic acid, hexahydrophthalic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, dimer fatty acid, esters of dicarboxylic acid, and anhydrides thereof.  
     
     
         6 . The coating composition of  claim 2 , wherein the polyisocyanate compound is selected from the group consisting of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-biphenylene diisocyanate, toluene diisocyanate, cyclohexyl diisocyanate, tetramethyl xylene diisocyanate, ethylethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-phenylene diisocyanate, 1,5-naphthalene diisocyanate, bis-(4-isocyanatocyclohexyl)-methane, and 4,4′-diisocyanatiodiphenyl ether.  
     
     
         7 . The coating composition of  claim 1 , wherein the crosslinker is selected from the group consisting of blocked polyisocyanates, phenolics, and amino resins.  
     
     
         8 . The coating composition of  claim 1 , wherein the coating composition comprises about 5 to 15 weight percent crosslinker.  
     
     
         9 . The coating composition of  claim 1 , wherein the coating composition comprises about 70 to 95 weight percent crosslinkable polyester-polyurethane polymer.  
     
     
         10 . The coating composition of  claim 1 , wherein the coating composition further comprises an adjuvant selected from the group consisting of carriers, lubricants, pigments, rheological control agents, and flow control agents.  
     
     
         11 . A coated package, comprising: 
 a substrate;    a cured coating produced from a composition having a crosslinkable polyester-polyurethane polymer having at least two carbamate sites;    a crosslinker; and    at least one adjuvant selected from the group consisting of carriers, lubricants, pigments, rheological control agents, and flow control agents.    
     
     
         12 . The coated package of  claim 11 , wherein the crosslinkable polyester-polyurethane polymer is formed from the reaction of a hydroxy functional polyester intermediate and a polyisocyanate compound.  
     
     
         13 . The coated package of  claim 12 , wherein the hydroxy functional polyester intermediate is a reaction product of a diol having between 2 and 12 carbon atoms and a dicarboxylic acid having between 4 and 40 carbon atoms.  
     
     
         14 . The coated package of  claim 13 , wherein the diol is selected from the group consisting of butane diol, butyl ethyl propane diol, 2-methyl 1,3-propane diol, 1,3-propane diol, hexane diol, cyclohexane dimethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, and hydroxypivalyl hydroxypivalate; and the dicarboxylic acid is selected from the group consisting of adipic acid, azelaic acid, sebacic acid, naphthalene dicarboxylic acid, dodecane dicarboxylic acid, cyclohexane dicarboxylic acid, hexahydrophthalic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, dimer fatty acid, esters of dicarboxylic acid, and anhydrides thereof. .  
     
     
         15 . The coated package of  claim 12 , wherein the polyisocyanate compound is selected from the group consisting of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-biphenylene diisocyanate, toluene diisocyanate, cyclohexyl diisocyanate, tetramethyl xylene diisocyanate, ethylethylene diisocyanate, 2,3-dimethylethylene diisocyanate, 1-methyltrimethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-phenylene diisocyanate, 1,5-naphthalene diisocyanate, bis-(4-isocyanatocyclohexyl)-methane, and 4,4′-diisocyanatiodiphenyl ether.  
     
     
         16 . The coated package of  claim 11 , wherein the coating composition comprises about 70 to 95 weight percent crosslinkable polyester-polyurethane polymer  
     
     
         17 . The coated package of  claim 11 , wherein the coated substrate is selected from the group consisting of: aluminum, tin-free steel, and electrolytic tin plate.  
     
     
         18 . The coated package of  claim 11 , wherein the thickness of the cured coating is between about 2 and 10 microns.  
     
     
         19 . The coated package of  claim 11 , wherein the coating is on the interior of the coated package.  
     
     
         20 . The coated package of  claim 11 , wherein the coated substrate is formed into a Draw-Redraw can.