Process for preparing aqueous dispersions of acrylic-urethane graft copolymers

Abstract

Ethylenically unsaturated aqueous urethane dispersions of controlled molecular weight are prepared by first reacting an active hydrogen atom containing polymerizable vinyl compound with a diisocyanate to produce a monoacrylated diisocyanate adduct in the presence of excess diisocyanate. The adduct thus formed, being a nearly selectively made mono-ethylenically unsaturated mono-isocyanate compound, is used in preparing an aqueous urethane polymer dispersion by reacting this adduct with polyisocyanates, organic compounds containing active hydrogen atoms like polyols and polyamines and organic compounds containing at least one active hydrogen atom and at least one group capable of saltformation, followed by neutralizing, dispersing in water and chain-extending the prepolymer. This ethylenically unsaturated aqueous urethane polymer dispersion is subjected to an emulsionpolymerization by conventional techniques with acrylate, methacrylate and related polymerizable compounds, yielding an aqueous dispersion of an urethane-acrylate graft copolymer. These urethane-acrylate graft copolymers are particularly useful as binders for coatings, printing inks and related applications.

Dependencies are inferred from the claim text.