Rheological methods for high block, tack and scrub resistant coating composition

Abstract

The present invention is directed to a coating composition or paint comprising a multistage latex with at least first and second stages, wherein the composition or paint is substantially free of volatile organic compounds (VOC) and capable of film formation even in the absence of coalescent agents. The base paint formulation is capable of being tinted at a point-of-sale (i.e. in-store) using a colorant composition of a type and quantity required to produce a paint of desired color and finish. The paints, show improved block resistance, scrub resistance and tack resistance. Rheological techniques as described herein may be used to determine tack resistance, print resistance, and other performance characteristics.

1 - 20 . (canceled) 
     
     
         21 . A coating composition comprising a multistage latex polymer derived from monomers comprising a crosslinking component comprising diacetone acrylamide (DAAM), wherein the multistage latex polymer comprises at least two stages with different Tg values, wherein at least one stage has a Tg of about 0 to 120° C. and at least another stage has a Tg of about −35 to about 10° C. 
     
     
         22 . The coating composition of  claim 21 , wherein the coating composition comprises a base paint present in a paint container, and wherein the base paint has a volatile organic content (VOC) of less than about 5 wt %. 
     
     
         23 . The coating composition of  claim 22 , wherein the coating composition is not made using a fluorosurfactant. 
     
     
         24 . The coating composition of  claim 21 , wherein the difference in Tg values is about 35° C. to 65° C. 
     
     
         25 . The coating composition of  claim 23 , wherein the difference in Tg values is at least about 50° C. 
     
     
         26 . The coating composition of  claim 21 , wherein the coating composition has scrub resistance of at least 1,000, storage modulus (E′) of about 1.0×10 6  to 1.0×10 7  Pa at 60° C. and 0.1 rad/s and tan (δ) of less than about 0.2 at 60° C. and 0.1 rad/s. 
     
     
         27 . The coating composition of  claim 21 , wherein each of the monomer mixtures of the at least two stages includes methyl methacrylate. 
     
     
         28 . The coating composition of  claim 27 , wherein each of the monomer mixtures of the at least two stages includes methyl methacrylate and butyl acrylate. 
     
     
         29 . The coating composition of  claim 27 , wherein each of the monomer mixtures of the at least two stages includes methacrylic acid. 
     
     
         30 . The coating composition of  claim 28 , wherein each of the monomer mixtures of the at least two stages includes methacrylic acid. 
     
     
         31 . The coating composition of  claim 30 , wherein the coating composition has a scrub resistance of at least 800. 
     
     
         32 . The coating composition of  claim 31 , wherein the coating composition has a volatile organic content (VOC) of less than about 5 wt %. 
     
     
         33 . The coating composition of  claim 32 , wherein the coating composition is not made using a fluorosurfactant. 
     
     
         34 . The coating composition of  claim 21 , wherein the multistage latex is capable of forming a film at a temperature of 4° C. or less. 
     
     
         35 . The coating composition of  claim 21 , wherein the multistage latex is capable of forming a film at a temperature of 10° C. or less, in the absence of a separate coalescing agent. 
     
     
         36 . The coating composition of  claim 21 , wherein each of the monomer mixtures of the first and second stages includes a ureido-functional monomer. 
     
     
         37 . The coating composition of  claim 21 , wherein the coating composition includes about 5 to 15 wt % of colorant. 
     
     
         38 . The coating composition of  claim 37 , wherein the coating composition includes about 8 to 12 wt % of colorant. 
     
     
         39 . The coating composition of  claim 21 , wherein the coating composition has a scrub resistance of at least 1,100.