Hybrid polyurethane spray foams made with urethane prepolymers and rheology modifiers

Abstract

Hybrid spray foams utilize a urethane reactant, a crosslinker, and an (optional) epoxy and/or acrylic resin along with a blowing agent and rheology modifier to produce a quick-setting foam that remains in place until the foam forms and cures. The urethane reactant may be formed as an adduct with or without the use of isocyanate chemistry. In some embodiments, the polyurethane oligomer is made by reacting cyclocarbonates and di- or polyamines, while in other embodiments the polyurethane backbone employs the use of commercially available capped or blocked urethane oligomers made by any method. The oligomers contain reactive groups, typically at the oligomer ends, that crosslink with crosslinkers or with acrylic or epoxy resins to form hybrid polyurethane foams. Foams may also contain a plasticizer, and/or a surfactant as well as other optional additives. Methods of making such foams are also provided.