Rapid drying lacquers containing triblock copolymer for rheology control

Abstract

This invention relates to rapid drying lacquers that are particularly useful for automotive OEM refinish applications. The lacquer includes a novel acrylic triblock copolymer as a replacement material for all or part of the cellulose acetate butyrate binder component. This invention is also directed to a process for producing coatings from the rapid drying lacquers. These lacquers are especially useful in providing chip and humidity resistant coatings, especially metallic effect coatings, having excellent adhesion and down flop or metallic effect.

1 . A triblock copolymer composition, wherein the block copolymer contains a polymeric A block, a polymeric B block, and a polymeric A′ block: wherein 
 (a) the polymeric A block is of polymerized ethylenically unsaturated monomer(s);    (b) the polymeric B block is of a polymerized ethylenically unsaturated monomer(s); and    (c) the polymeric A′ block is of polymerized ethylenically unsaturated monomer(s); and further wherein    the A and A′ blocks have the same or similar composition and the B block has a different composition from the A and A′ blocks;    the A and A′ blocks differ from the B block by the presence of one or more functional groups that are capable of interacting with each other for the formation of a reversible network; and    the functional groups are selected from at least one of the group consisting of carboxylic acid, hydroxyl, urea, amide, and ethylene oxide groups, and any mixtures thereof.    
   
   
       2 . The composition of  claim 1 , wherein the B block on the copolymer is a non-functional block, essentially free of functional groups.  
   
   
       3 . The composition of  claim 1 , wherein at least 1% by weight of the monomers used to form the A and A′ blocks contain interactive functional groups.  
   
   
       4 . The composition of  claim 1 , wherein about 5 to 60% by weight of the monomers used to form the functional blocks A and A′ contain interactive functional groups.  
   
   
       5 . The composition of  claim 1 , wherein the blocks are linearly attached to each other in the order given, each at a single terminal point thereof.  
   
   
       6 . The composition of  claim 4 , wherein the block copolymer is made primarily from acrylic monomers.  
   
   
       7 . The composition of  claim 1 , wherein the ABA′ block copolymer is prepared by a macromonmer approach using cobalt as a catalytic chain transfer agent.  
   
   
       8 . The composition of  claim 7 , wherein the block copolymer is made primarily from acrylic or methacrylic monomers or mixtures thereof.  
   
   
       9 . The composition of  claim 1 , wherein the network-forming group comprises at least one carboxylic acid group.  
   
   
       10 . The composition of  claim 1 , wherein the ABA′ block copolymer is tapered between AB and/or BA′ block.  
   
   
       11 . A triblock copolymer composition, wherein the block copolymer has a weight average molecular weight of about 5,000 to 200,000 and contains a polymeric A block, a polymeric B block, and a polymeric A′ block: wherein 
 (a) the polymeric A block is of polymerized ethylenically unsaturated monomer(s);    (b) the polymeric B block is of a polymerized ethylenically unsaturated monomer(s); and    (c) the polymeric A′ block is of polymerized ethylenically unsaturated monomer(s); and further wherein the weight average molecular weight of each block is at least 1,000 and    the A and A′ blocks have the same or similar composition and the B block has a different composition from the A and A′ blocks;    the A and A′ blocks differ from the B block by the presence of one or more functional groups that are capable of interacting with each other for the formation of a reversible network; and    the functional groups are selected from at least one of the group consisting of carboxylic acid, hydroxyl, urea, amide, and ethylene oxide groups, and any mixtures thereof.    
   
   
       12 . The composition of  claim 11 , wherein the B block on the copolymer is a non-functional block, essentially free of functional groups.  
   
   
       13 . The composition of  claim 11 , wherein at least 1% by weight of the monomers used to form the A and A′ blocks contain interactive functional groups.  
   
   
       14 . The composition of  claim 11 , wherein about 5 to 60% by weight of the monomers used to form the functional blocks A and A′ contain interactive functional groups.  
   
   
       15 . The composition of  claim 11 , wherein the blocks are linearly attached to each other in the order given, each at a single terminal point thereof.  
   
   
       16 . The composition of  claim 15 , wherein the block copolymer is made primarily from acrylic monomers.  
   
   
       17 . The composition of  claim 11 , wherein the ABA′ block copolymer is prepared by a macromonmer approach using cobalt as a catalytic chain transfer agent.  
   
   
       18 . The composition of  claim 17 , wherein the block copolymer is made primarily from acrylic or methacrylic monomers or mixtures thereof.  
   
   
       19 . The composition of  claim 11 , wherein the network-forming group comprises at least one carboxylic acid group.  
   
   
       20 . The composition of  claim 11 , wherein the ABA′ block copolymer is tapered between AB and/or BA′ block.