Aqueous coating composition with improved adhesion to friable surfaces

A method for producing a coating on a friable surface comprising:

• (1) applying to said friable surface a layer of an aqueous coating composition comprising a plurality of polymeric particles, each of said particles consisting essentially of:
• (a) at least one polymer A having a glass transition temperature of −20° C. to 100° C.,
• wherein said polymer A is an emulsion polymer comprising:
• (i) 5-99.5% by weight, based on said polymer A weight, of at least one copolymerized ethylenically unsaturated first nonionic monomer having a water solubility at 25° C. of 8% or more by weight, based on the weight of water;
• (ii) 0-94.5% by weight, based on said polymer A weight, of at least one copolymerized ethylenically unsaturated second nonionic monomer having a water solubility at 25° C. of less than 8% by weight, based on the weight of water;
• and
• (iii) at least one copolymerized acid monomer, such that the acid number of said polymer A is 3 to 100 mg of KOH per g of polymer;
• and
• (b) at least one polymer B having a glass transition temperature of −20° C. to 100° C., wherein said polymer B is an emulsion polymer comprising, as polymerized units, at least one ethylenically unsaturated nonionic monomer,
• wherein said particles have an average particle diameter less than 120 nanometers;
• and
• (2) drying said coating composition.