| 摘要 |
The present invention provides aqueous coating compositions comprising one or more emulsion copolymer made from itaconic acid, a sulfonic acid or sulfonate ester monomer and an additional acid monomer which is a carboxylic acid and having a glass transition temperature of from -45°C to -10°C, and one or more pigment, opacifier, filler, extender, or mixture of any of these at a %PVC of from 20 to 55, preferably 30 to 50, wherein coatings made from the coating compositions provide improved resistance to water swelling and dirt pickup resistance. The improvements are observed regardless of whether the compositions contain or are substantially free of zinc or divalent metal ions, or salts or compounds containing them. The present invention also provides roofing substrates coated with the aqueous compositions. |
