Patent ID: 6280561
Filing Date: 2001-08-28
Classification: C08G,C09J

Abstract:
A method for adhesively joining or sealing two substrates which comprises:(1) applying onto a substrate a solvent-free, moisture curable urethane hot melt adhesive composition comprising the polyisocyanate prepolymer reaction product of (a) a polyether or polyester polyol containing X OH groups (where X is at least 2), and (b) a polyisocyanate having an NCO functionality of at least two, the adhesive composition being applied at an elevated temperature sufficient to melt extrude the adhesive composition;(2) contacting the melt extruded adhesive disposed on the substrate with a second substrate such that a green bond is formed, and(3) exposing the adhesive bond to moisture causing a crosslinking reaction within the adhesive, thereby forming a moisture-cured bond, characterized in that the polyisocyanate prepolymer reaction product consists essentially of at least 90 wt % of a prepolymer having a polyisocyanate to polyol stoichiometry of X:1, the prepolymer reaction product containing less than 2 wt % unreacted polyisocyanate monomer and the prepolymer containing free NCO ranging from 0.2 to 8 wt %.