Water-Reducible Coating Composition

Abstract

The present description provides a water-reducible or water-dispersible coating system that can be used to form a durable, corrosion-resistant protective coating on a wide range of substrates. The coating system includes an alkyd resin prepared from a polyester feedstock that includes post-consumer recycled PET and a waste cooking oil feedstock. Methods for preparing the coating system and articles coated with the coating system are also described.

What is claimed is: 
     
         1 . A coating system, comprising:
 a water-reducible alkyd resin comprising the reaction product of   about 65 to 75 wt % of a polyester feedstock comprising at least one resin with a polyester backbone; and   
       about 25 to 35 wt % of a waste cooking oil feedstock comprising yellow grease, brown grease, or mixtures thereof. 
     
     
         2 . A method, comprising the steps of:
 providing a polyester feed stock, wherein the feedstock comprises polyethylene terephthalate derived from waste material;   
       a aromatic or aliphatic polycarboxylic acid; and 
       a polyol; 
       providing a waste cooking oil feedstock, wherein the feedstock comprises yellow grease, brown grease, or mixtures thereof; and 
       reacting the above reactants to produce a water-reducible alkyd resin. 
     
     
         3 . A coated article, comprising;
 at least a portion of an exposed surface of a metal substrate; and   a coating system applied to at least the exposed surface, wherein the coating system comprises the water-reducible alkyd resin of  claim 1 .   
     
     
         4 . The system of  claim 1 , wherein the feedstock including at least one resin with a polyester backbone is a polyalkylene terephthalate selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate and combinations thereof. 
     
     
         5 . The system of  claim 1 , wherein the at least one resin with a polyester backbone is polyethylene terephthalate. 
     
     
         6 . The system of  claim 1 , wherein the polyethylene terephthalate is derived from post-consumer waste material. 
     
     
         7 . The system of  claim 1 , wherein the feedstock including at least one resin with a polyester backbone is derived from the reaction of an aliphatic polycarboxylic acid with a hydroxy functional compound having at least two hydroxy groups. 
     
     
         8 . The system of  claim 1 , wherein the aliphatic polycarboxylic acid is derived from carboxylic acid monomers selected from phthalic acid, isophthalic acid, terephthalic acid, tetrahydroterephthalic acid, naphthalene dicarboxylic acid, anhydrides thereof, derivatives thereof, and combinations thereof. 
     
     
         9 . The system of  claim 1 , wherein the aliphatic polycarboxylic acid is a polyalkylene terephthalate selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and mixtures thereof. 
     
     
         10 . The system of  claim 1 , wherein the waste cooking oil feedstock is selected from yellow grease, brown grease, or a combination thereof. 
     
     
         11 . A method of coating an article, comprising:
 providing an article, wherein at least a portion of an exposed surface of the article comprises a metal substrate; and   applying the water-reducible coating system of  claim 1  to at least the underbody.   
     
     
         12 . The system of  claim 1 , wherein the hydroxy-functional compound is selected from ethylene glycol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, propylene glycol, 1,2-propylene glycol, 1,3-propane diol, 1,2-butylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, erythritol, derivatives thereof, or combinations thereof. 
     
     
         13 . The system of  claim 1 , wherein the carboxyl-functional compound is selected from trimellitic acid, trimellitic anhydride, maleic acid, maleic anhydride, fumaric acid, isophthalic acid, and combinations thereof. 
     
     
         14 . The system of  claim 1 , wherein the hydroxy-functional compound is pentaerythritol. 
     
     
         15 . The system of  claim 1 , wherein the carboxyl-functional compound is trimellitic acid. 
     
     
         16 . The system of  claim 1 , wherein the polyester feedstock further includes about 1 to 10 wt % linseed oil. 
     
     
         17 . The system of  claim 1 , wherein the alkyd resin composition has an acid number of about 40 to about 70. 
     
     
         18 . The system of  claim 1 , wherein the alkyd resin composition has a molecular weight (Mn) of 1000 to 10,000. 
     
     
         19 . The system of  claim 1 , wherein the article comprises at least a part of an underbody of a transportation vehicle or storage unit. 
     
     
         20 . The system of  claim 1 , wherein the article is a shipping container.