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.

1 . A spray foam system comprising
 a urethane reactant having at least two reactive functional groups other than isocyanates, the urethane reactant selected from (a) a preformed urethane prepolymer and (b) a cyclocarbonate and a polyamine that react in situ to form a urethane prepolymer adduct;   a crosslinker having at least two reactive functional groups adapted to be rapidly crosslinked with the reactive functional groups of the urethane reactant to form a hybrid polyurethane, optionally with a resin polymer having further reactive functional groups;   a blowing agent for initiating a foaming reaction; and   a rheology modifier;   wherein the urethane reactant, the crosslinker and the optional resin polymer are separated into at least two parts on the basis of their reactive functional groups to prevent premature crosslinking until a foaming reaction is initiated.   
     
     
         2 . The spray foam system of  claim 1  wherein the urethane reactant comprises a urethane acrylate adduct. 
     
     
         3 . The spray foam system of  claim 1  wherein the urethane reactant comprises a mixture of a cyclocarbonate and a polyamine capable of forming a cyclocarbonate-amine urethane adduct in the presence of heat. 
     
     
         4 . The spray foam system of  claim 3  further comprising an acrylate monomer reactive with the polyamine to produce internal heat. 
     
     
         5 . The spray foam system of  claim 1  wherein the resin polymer comprises an epoxy polymer, curable with a polyamine, the epoxy polymer and polyamine being in separate parts initially. 
     
     
         6 . The spray foam system of  claim 5 , further comprising an auxiliary cros slinking agent comprising an acrylate monomer. 
     
     
         7 . The spray foam system of  claim 1  wherein the urethane reactant comprises an aliphatic backbone. 
     
     
         8 . The spray foam system of  claim 1  wherein the urethane reactant comprises an aromatic backbone. 
     
     
         9 . The spray foam system of  claim 1  wherein at least some of the reactive functional groups of the urethane reactant are amine reactive groups. 
     
     
         10 . The spray foam system of  claim 1  wherein at least some of the reactive functional groups of the urethane reactant are vinyl reactive groups. 
     
     
         11 . The spray foam system of  claim 1  wherein the blowing agent is a low-boiling point fluorocarbon. 
     
     
         12 . The spray foam system of  claim 11  wherein the low-boiling point fluorocarbon is selected from HFC 245fa, FEA-1100 and mixtures thereof. 
     
     
         13 . A method of sealing, insulating or sealing and insulating part of a building structure, comprising
 mixing the at least two parts containing the components of the spray foam system of  claim 1 ;   applying the mixture to the building structure, thereby permitting the urethane reactant, the crosslinker and optional resin polymer to crosslink, and   initiating a blowing reaction to form a foamed product,   the rheology modifier holding the mixture in place against the building structure for a time sufficient for the blowing agent to produce a three-dimensional, tack-free foamed product.   
     
     
         14 . The method of  claim 13 , further comprising heating one or more of the at least two parts to a temperature above ambient temperature prior to or at the time of application. 
     
     
         15 . The method of  claim 13  further comprising delivering each of the at least two parts to a spray device, blending them there, and applying them from the spray device. 
     
     
         16 . The method of  claim 13  wherein the foamed product cures to tack-free status in less than about 120 seconds. 
     
     
         17 . The method of  claim 13  wherein the foamed product cures to resilient hardness in less than about 15 minutes. 
     
     
         18 . The method of  claim 13  wherein the part of the building structure is a seam or crevice between two structural components. 
     
     
         19 . The method of  claim 13  wherein the part of the building structure is a cavity or open space framed by structural components. 
     
     
         20 . The method of  claim 13  wherein the blowing reaction is initiated by de-pressurization of a low-boiling point fluorocarbon. 
     
     
         21 . A hybrid polyurethane foamed product made by the process of:
 reacting non-isocyanate reactive functional groups of a urethane reactant with a crosslinker having at least two reactive functional groups adapted to be rapidly crosslinked with the reactive functional groups of the urethane reactant to form a hybrid polyurethane, optionally with a resin polymer having further reactive functional groups, in the presence of a rheology modifier under conditions to rapidly form cells of a crosslinked hybrid polyurethane polymer; while initiating a blowing reaction to cause a gas to be disposed within at least some of the cells.   
     
     
         22 . The foamed product of  claim 21  wherein the cells are at least 80% closed. 
     
     
         23 . The foamed product of  claim 21  wherein the urethane reactant is selected from those having an aliphatic backbone, those having an aromatic backbone, those having polyesters in the backbone, and those having polyether in the backbone. 
     
     
         24 . The foamed product of  claim 21  further comprising an epoxy resin. 
     
     
         25 . The foamed product of  claim 21  further comprising an acrylate monomer. 
     
     
         26 . The foamed product of  claim 21  wherein the blowing reaction gas is a low-boiling point fluorocarbon.