Non-polymeric acetoacetates as adhesion promoting coalescing agents

Abstract

This invention provides esters of acetoacetic acid useful as adhesion promoters for waterborne coatings compositions applied to corroded or rusty metal substrates. The esters of acetoacetic acid also function as a coalescing aid in the coating composition.

1. A method for coating a substrate, comprising forming a waterborne coating composition comprising:
 (A) a waterborne alkyd dispersion polymer,  
 (B) a compound of Formula (I): 
   (R 1 C(═O)CH 2 COO) x R 2,    
 
 wherein R 1  is a C 1 -C 6  alkyl group, R 2  is a C 1 -C 6  alkyl group or the residue of a polyol and x is an integer of from 1 to 3, with the proviso that (B) contains no substitutes  substituents that are reactive with (A); and  
 applying said waterborne coating composition to a substrate.  
 
     
     
       2. The method of  claim 1 , wherein R 1  is methyl, R 2  is t-butyl and x is 1. 
     
     
       3. The method of  claim 1 , wherein R 1  is methyl, R 2  is ethyl and x is 1. 
     
     
       4. The method of  claim 1 , wherein R 1  is ethyl, R 2  is butyl and x is1. 
     
     
       5. The method of  claim 1 , wherein the compound of Formula (I) is selected from the group consisting of ethylene glycol bis(acetoacetate); diethylene glycol bis(acetoacetate); propylene glycol bis(acetoacetate); 2,2,4-trimethylene glycol bis(acetoacetate); cyclohexanediol bis(acetoacetate); trimethylpropane tris(acetoacetate), glycerol tris (acetoacetate), 2-butyl-2-ethyl-1,3-propane diol bis (acetoacetate) and ethyl acetoacetate. 
     
     
       6. The method of  claim 1 , wherein (B) is present in an amount of from 1 to 25 parts by weight of (B) per 100 parts of (A). 
     
     
       7. The method of  claim 1 , wherein the substrate is selected from the group consisting of steel, aluminum, galvanized sheeting, rusty and corroded substrates. 
     
     
       8. A method for coating a substrate, comprising the step of applying to a substrate a waterborne coating composition, where the waterborne coating composition comprises:
 ( A )  an aqueous dispersion of an alkyd, and      ( B )  a compound of Formula  ( I ) :  
   ( R   1   C (═ O ) CH   2   COO ) x   R   2   ,    
     wherein R   1  is a C 1   -C   6    alkyl group, R   2    is a C   1   -C   6    alkyl group or the residue of a polyol and x is an integer of from  1  to  3 , with the proviso that  ( B )  contains no substituents that are reactive with  ( A ) .      
     
     
       9. A method of  claim 8 , wherein R 1    is methyl, R   2    is t - butyl and x is  1 .    
     
     
       10. A method of  claim 8 , wherein R 1    is methyl, R   2    is ethyl and x is  1 .    
     
     
       11. A method of  claim 8 , wherein R 1    is ethyl, R   2    is butyl and x is  1 .    
     
     
       12. A method of  claim 8 , wherein the compound of Formula ( I )  is selected from the group consisting of ethylene glycol bis ( acetoacetate)   ; diethylene glycol bis ( acetoacetate ) ; propylene glycol bis ( acetoacetate ) ;  2 , 2 , 4   - trimethylene glycol bis ( acetoacetate)   ; cyclohexanediol bis ( acetoacetate ) ; trimethylpropane tris ( acetoacetate ) ; glycerol tris ( acetoacetate ) ;  2   - butyl -   2   - ethyl -   1 , 3   - propane diol bis ( acetoacetate )  and ethyl acetoacetate.    
     
     
       13. A method of  claim 8 , wherein Formula ( I )  is present in an amount ranging from  1  to  25  parts by weight of Formula  ( I )  per  100  parts of the polymer.    
     
     
       14. A method of  claim 8 , wherein the substrate is selected from the group consisting of steel, aluminum, galvanized sheeting, rusty and corroded substrates.