Aqueous coating compositions for forming anti-grain-puffing coatings on wood substrate, aqueous paints, and articles

Abstract

The present invention relates to aqueous coating compositions for forming an anti-grain-puffing coating, aqueous primers comprising the aqueous coating composition, and articles comprising the anti-grain-puffing coating. In particular, the aqueous coating composition comprises: (a) an aqueous dispersion of polymeric particles, wherein the polymer particles comprise polymer having an anionic hydrophilic group on its molecule chain, and the aqueous dispersion of polymeric particles has a pH of less than 7.0; and (b) an aqueous dispersion of nano-silica.

What is claimed is: 
     
         1 . An aqueous coating composition for forming an anti-grain-puffing coating on a wood substrate, comprising:
 (a) an aqueous dispersion of polymeric particles, wherein the polymeric particles comprise polymer having an anionic hydrophilic group on its molecule chain, and the aqueous dispersion of polymeric particles has a pH of less than 7.0; and   (b) an aqueous dispersion of nano-silica.   
     
     
         2 . The aqueous coating composition of  claim 1 , wherein the aqueous dispersion of polymeric particles has a pH of more than 5.0. 
     
     
         3 . The aqueous coating composition of  claim 1 , wherein the aqueous dispersion of polymeric particles has a pH of more than 6.0. 
     
     
         4 . The aqueous coating composition of  claim 1 , wherein the anionic hydrophilic group is selected from a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a phosphonite group, a phosphoric acid group and the combination thereof. 
     
     
         5 . The aqueous coating composition of  claim 1 , wherein the aqueous dispersion of polymeric particles has a hydroxyl value of 0-100 mg KOH/g, preferably 20-80 mg KOH/g. 
     
     
         6 . The aqueous coating composition of  claim 1 , wherein the polymer particles have a particle size of less than 100 nm. 
     
     
         7 . The aqueous coating composition of  claim 1 , wherein the aqueous dispersion of polymeric particles comprises an aqueous dispersion of silicone, an aqueous dispersion of styrene-acrylate, an aqueous dispersion of acrylates, an aqueous dispersion of silicone modified acrylate, an aqueous dispersion of vinyl acetate, an aqueous dispersion of vinyl acetate-acrylates, an aqueous dispersion of vinyl acetate-ethylene, an aqueous dispersion of ethylene-vinyl acetate, an aqueous dispersion of vinyl acetate-acrylates-ester of versatic acid or any combination thereof. 
     
     
         8 . The aqueous coating composition of  claim 7 , wherein the aqueous dispersion of polymeric particles has a solid content of 30-50%. 
     
     
         9 . The aqueous coating composition of  claim 1 , wherein the nano-silica has a particle size in the range of 5-100 nm. 
     
     
         10 . The aqueous coating composition of  claim 1  comprising, based on the total weight of the aqueous coating composition,
 70-90 wt % of the aqueous dispersion of polymeric particles; 
 0.1-10 wt % of the aqueous dispersion of nano-silica; and 
 0-29.9 wt % of additional additives. 
 
     
     
         11 . The aqueous coating composition of  claim 1 , wherein the coating composition is a primer for a wood substrate. 
     
     
         12 . A two-part aqueous primer for forming an anti-grain-puffing coating on a wood substrate, comprising
 (a) an aqueous coating composition, comprising:   (i) an aqueous dispersion of polymeric particles, wherein the polymeric particles comprise polymer having an anionic hydrophilic group on its molecule chain, and the aqueous dispersion of polymeric particles has a pH of less than 7.0; and   (ii) an aqueous dispersion of nano-silica; and   (b) a blocked isocyanate.   
     
     
         13 . The two-part aqueous primer of  claim 12 , wherein the blocked isocyanate is selected from the group consisting of a blocked aliphatic polyisocyanate, a blocked cycloaliphataic polyisocyanate, a blocked aromatic polyisocyanate and the combination thereof. 
     
     
         14 . An article, comprising
 (a) a wood substrate having at least one major surface;   (b) an anti-grain-puffing coating directly applied on the major surface of the wood substrate, formed from the aqueous coating composition comprising: (a) an aqueous dispersion of polymeric particles, wherein the polymeric particles comprise polymer having an anionic hydrophilic group on its molecule chain, and the aqueous dispersion of polymeric particles has a pH of less than 7.0; and   (b) an aqueous dispersion of nano-silica; and   (c) a coating applied on the anti-grain-puffing coating, formed from an aqueous coating composition.   
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . (canceled)