Silicone-Modified Polyester Coating

Abstract

A silicone-modified polyester resin and methods for making the resin are described herein. The method includes production of a siliconized intermediate which is then esterified to give a silicone-modified polyester resin. Coating compositions including the silicone-modified polyester resin are provided, and coated articles with the coating composition applied to at least a portion of a surface thereof are also provided.

What is claimed is: 
     
         1 . A method of making a siliconized polyester, comprising:
 providing at least one hydroxy-functional silicone compound;   providing at least one hydroxy-functional compound;   combining the hydroxy-functional silicone compound and the hydroxy-functional compound to produce a siliconized hydroxy-functional polymer; and   esterifying the siliconized hydroxy-functional polymer with at least one carboxylic acid-functional compound or derivative thereof to form the siliconized polyester.   
     
     
         2 . The method of  claim 1 , wherein the hydroxy-functional silicone compound is a low molecular weight compound with silicone content of at least about 30 wt %, based on the total weight of the composition. 
     
     
         3 . The method of  claim 1 , wherein the hydroxy-functional silicone has molecular weight (Mn) of 500 to 1200. 
     
     
         4 . The method of  claim 1 , wherein the hydroxy-functional silicone has molecular weight (Mw) of about 1000 to 2400. 
     
     
         5 . The method of  claim 1 , wherein the siliconized hydroxy-functional polymer has Mw of about 3000 to about 4500. 
     
     
         6 . The method of  claim 1 , wherein the siliconized hydroxy-functional polymer has OH number of at least about 85. 
     
     
         7 . The method of  claim 1 , wherein the hydroxy-functional compound is a polyol. 
     
     
         8 . The method of  claim 1 , wherein the hydroxy-functional compound is a polyol is selected from 1,6-hexanediol, pentaerythritol, trimethylolpropane, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, trimethylol ethane, 3-hydroxy-2,2-dimethylpropyl 3-hydroxy-2,2-dimethylpropionate (HPHP), and combinations thereof. 
     
     
         9 . The method of  claim 1 , wherein the hydroxy-functional compound is a polyol selected from 1,6-hexanediol, trimethylolpropane, neopentyl glycol, ethylene glycol, 3-hydroxy-2,2-dimethylpropyl 3-hydroxy-2,2-dimethylpropionate (HPHP), and combinations thereof. 
     
     
         10 . The method of  claim 1 , wherein the carboxylic-acid functional compound is a polyacid or derivative thereof. 
     
     
         11 . The method of  claim 1 , wherein the carboxylic-acid functional compound is a polyacid selected from phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalate, benzophenone dicarboxylic acid, diphenic acid, 4,4-dicarboxydiphenyl ether, 2,5-pyridine dicarboxylic acid, 2,6-naphthalenedicarboxylic acid , 4-hydroxybenzoic acid, trimellitic acid, trimellitic anhydride, and combinations thereof. 
     
     
         12 . The method of composition of any of the above claims, wherein the hydroxy-functional silicone compound and the hydroxy-functional compound are present in a 1:2 ratio. 
     
     
         13 . The method of  claim 1 , wherein the siliconized hydroxy-functional polymer and the carboxylic acid-functional compound are present in a 1:1 ratio. 
     
     
         14 . The method of  claim 1 , wherein the siliconized polyester has an acid number of about 4 to about 5. 
     
     
         15 . The method of  claim 1 , wherein the siliconized polyester has hydroxyl number of about 75 to about 80. 
     
     
         16 . The method of  claim 1 , wherein the siliconized polyester has Gardner viscosity of N. 
     
     
         17 . The method of  claim 1 , further comprising a catalyst. 
     
     
         18 . The method of  claim 1 , further comprising a catalyst selected from stannous oxalate, stannous chloride, butylstannoic acid, dibutyl tin oxide, tetrabutyltitanate, or tetra butylzirconate, and mixtures thereof. 
     
     
         19 . The method of  claim 1 , further comprising a tetrabutyl titanate catalyst. 
     
     
         20 . A method, comprising:
 providing a planar metal substrate having the coating composition of  claim 1  applied on at least a portion of the metal substrate; and   curing the coating composition on the substrate to form a coated article.