Emulsion polymers and low voc coating compositions made therefrom

Abstract

Emulsion polymers and coating compositions made therefrom that exhibit exceptional roller stability and stain resistance to both hydrophilic and hydrophobic stains, without sacrificing scrub resistance. The emulsion polymers include, as polymerized units formed at a pH between 3 and 9: a) at least one nonionic or anionic unsaturated monomer in an amount ranging between about 78 wt. % to less than 100 wt. % based on the overall weight of the polymer composition b) one or more strong acid monomer in an amount ranging from about 0.01 wt. % to 2 wt. % based on the overall weight of the polymer composition; and c) at least one lower alkyl acrylate monomer in an amount ranging between about 1 wt. % to 20 wt. % based on the overall weight of the polymer composition.

1 . An emulsion polymer composition comprising, as polymerized units:
 a) at least one nonionic or anionic unsaturated monomer in an amount ranging between about 78 wt. % to less than 100 wt. % based on the overall weight of the polymer composition   b) one or more strong acid monomer in an amount ranging from about 0.01 wt. % to 2 wt. % based on the overall weight of the polymer composition; and   c) at least one lower alkyl acrylate monomer in an amount ranging between about 1 wt. % to 20 wt. % based on the overall weight of the polymer composition.   
     
     
         2 . The emulsion polymer according to  claim 1 , wherein the polymerized units are formed at a pH between 3 and 9. 
     
     
         3 . The emulsion polymer according to  claim 1 , wherein the ethylenically unsaturated nonionic or anionic monomer is methacrylic acid, butyl acrylate, methyl methacrylate, butyl methacrylate, styrene. 
     
     
         4 . The emulsion polymer according to  claim 1 , wherein the strong acid monomer is ethyl methacrylate phosphate, phosphate esters of polypropylene glycol monomethacrylate, or a mixture thereof. 
     
     
         5 . The emulsion polymer according to  claim 1 , wherein the lower alkyl acrylate monomer is methyl acrylate, ethyl acrylate, propyl acrylate, or a mixture thereof. 
     
     
         6 . A coating composition comprising an emulsion polymer dispersed in an aqueous medium, the emulsion polymer comprising, as polymerized units:
 a) at least one nonionic or anionic unsaturated monomer in an amount ranging between about 78 wt. % to less than 100 wt. % based on the overall weight of the polymer composition   b) one or more strong acid monomer in an amount ranging from about 0.01 wt. % to 2 wt. % based on the overall weight of the polymer composition; and   c) at least one lower alkyl acrylate monomer in an amount ranging between about 1 to 20 wt. % based on the overall weight of the polymer composition;   wherein the polymerized units are formed at a pH between 3 and 9.   
     
     
         7 . The coating composition according to  claim 6 , wherein the coating composition comprises less than about 50 grams per liter of a volatile organic compound (VOC). 
     
     
         8 . The coating composition according to  claim 6 , wherein the ethylenically unsaturated nonionic or anionic monomer is methacrylic acid, butyl acrylate, methyl methacrylate, butyl methacrylate, styrene. 
     
     
         9 . The coating composition according to  claim 6 , wherein the strong acid monomer is ethylmethacrylate phosphate, phosphate esters of polyethylene glycol mono(meth)acrylate, phosphate esters of polypropylene glycol mono(meth)acrylate, or a mixture thereof. 
     
     
         10 . The coating composition according to  claim 6 , wherein the lower alkyl acrylate monomer is methyl acrylate, ethyl acrylate, propyl acrylate, or a mixture thereof. 
     
     
         11 . The coating composition according to  claim 6 , wherein the coating composition further comprises an organic pigment, and inorganic pigment, or a mixture thereof. 
     
     
         12 . The coating composition according to  claim 6 , wherein the coating composition further comprises one or more additives selected from the group of surfactants, dispersants, extenders, rheology modifiers, defoamers, coalescent agents, and opacifiers. 
     
     
         13 . The coating composition according to  claim 6 , wherein the emulsion polymer is present in an amount ranging from about 5 to 70 wt. % based on the entire weight of the coating composition. 
     
     
         14 . The coating composition according to  claim 13 , wherein the emulsion polymer is present in an amount ranging from about 10 to 60 wt. % based on the entire weight of the coating composition. 
     
     
         15 . A method of using the coating composition of  claim 6 , wherein the coating composition is applied to a surface of a substrate to form a film or coating layer on the surface;
 wherein the film or coating layer is resistant to both hydrophilic stains and hydrophobic stains.   
     
     
         16 . The method according to  claim 15 , wherein a total ΔE measured for the resistance of the film or coating layer to both the hydrophilic stains and hydrophobic stains is less than about 80;
 wherein the hydrophilic stains include mustard, ketchup, wine, coffee, and fountain ink; 
 wherein the hydrophobic stains include ballpoint pen, No. 2 pencil, blue crayon, grease pencil, lipstick #1 (CoverGirl Hot Passion), lipstick #2 (Maybelline Royal Red), and a consumers union stain. 
 
     
     
         17 . The method according to  claim 16 , wherein the total ΔE measured for the resistance of the film or coating layer to both the hydrophilic and hydrophobic stains is less than about 75. 
     
     
         18 . The method according to  claim 16 , wherein the total ΔE measured for the resistance of the film or coating layer to hydrophilic stains is less than about 40. 
     
     
         19 . The method according to  claim 16 , wherein the total ΔE measured for the resistance of the film or coating layer to hydrophobic stains is less than about 35. 
     
     
         20 . The method according to  claim 15 , wherein the roller stability of the coating is at least four cycles.