Redispersible polymer powder mixtures for use in dry-mix formulations having improved properties

摘要

A mixture contains: (a) an acrylic core-shell redispersible polymer powder with a core polymer that is an acrylic having a glass transition temperature in a range of −40 to 50 degrees Celsius and a shell polymer that is alkali soluble and contains more carboxyl-group functionalities than the core polymer and containing a nucleating agent having a boiling point of 150-500 degrees Celsius and a water solubility of 3.5 weight-percent or less; and (b) a second redispersible polymer powder selected from acetate ethylene copolymer redispersible polymer powders and polymer powders of a blend of vinyl acetate ethylene copolymer and vinyl ester of versatic acid copolymer; where the concentration of (a) is more than 20 weight-percent and less than 100 weight-percent of the total combined weight of (a) and (b). The mixture can further contain: (c) a Portland cement; (d) alumina rich cement; and (e) calcium sulfate.

主权项

1. A mixture comprising:
a. an acrylic core-shell redispersible polymer powder comprising an external shell polymer associated with an internal core polymer wherein the core polymer is an acrylic polymer having a glass transition temperature in a range of −40 to 50 degrees Celsius and the shell polymer is an alkali soluble polymer that contains more carboxyl-group functionalities than the core polymer, the acrylic core-shell redispersible powder further comprising a nucleating agent having a boiling point in a range of 150-500 degrees Celsius and a water solubility of 3.5 weight-percent or less; and b. a second redispersible polymer powder selected from vinyl acetate ethylene copolymer redispersible polymer powders and polymer powders of a blend of vinyl acetate ethylene copolymer and vinyl ester of versatic acid copolymer; where the concentration of the acrylic redispersible polymer powder (a) is more than 20 weight-percent and less than 100 weight-percent of the total combined weight of redispersible powders (a) and (b).