Two-component solventless adhesive compositions

Abstract

Two-component solventless polyurethane adhesive compositions comprising an isocyanate component and an isocyanate-reactive component are disclosed, the compositions comprising an isocyanate component comprising an isocyanate-terminated prepolymer, and an isocyanate-reactive component comprising a polyether polyol, a phosphate ester adhesion promoter, and, a bio-based polyol. Methods for forming laminate structures are also disclosed, the methods comprising forming an adhesive composition by mixing an isocyanate adhesive component comprising an isocyanate-terminated prepolymer and an isocyanate-reactive adhesive component comprising a polyether polyol, a phosphate ester adhesion promoter, and a bio-based polyol, applying the adhesive composition to a surface of a first substrate, and bringing a surface of a second substrate into contact with the adhesive composition on the surface of the first substrate, thereby forming the laminate structure. Laminate structures are also disclosed.

What is claimed is: 
     
         1 . A two-component solventless adhesive composition, comprising:
 an isocyanate component comprising an isocyanate-terminated prepolymer; and   an isocyanate-reactive component comprising:
 a polyether polyol; 
 a phosphate ester adhesion promoter; and 
 a bio-based polyol. 
   
     
     
         2 . The two-component solventless adhesive composition of  claim 1 , wherein the polyether polyol accounts for 10 to 90 percent of the total weight of the isocyanate-reactive component. 
     
     
         3 . The two-component solventless adhesive composition of  claim 1 , wherein the phosphate ester is made from a tri-functional propylene glycol, a polyphosphoric acid, and a polyisocyanate. 
     
     
         4 . The two-component solventless adhesive composition of  claim 1 , wherein the phosphate ester adhesion promoter accounts for 0.5 to 15 percent of the total weight of the isocyanate-reactive component. 
     
     
         5 . The two-component solventless adhesive composition of  claim 1 , wherein the bio-based polyol accounts for 5 to 80 percent of the total weight of the isocyanate-reactive component. 
     
     
         6 . The two-component solventless adhesive composition of  claim 1 , wherein the bio-based polyol is castor oil. 
     
     
         7 . The two-component solventless adhesive composition of  claim 1 , wherein the mole ratio of the NCO groups present in the isocyanate component to OH groups present in the isocyanate-reactive component is from 0.8:1.0 to 1.6:1.0. 
     
     
         8 . A laminate structure comprising the two-component solventless adhesive composition of  claim 1 . 
     
     
         9 . A method for forming a laminate structure, comprising:
 forming an adhesive composition by mixing an isocyanate adhesive component comprising an isocyanate-terminated prepolymer and an isocyanate-reactive adhesive component comprising a polyether polyol, a phosphate ester adhesion promoter, and a bio-based polyol;   applying the adhesive composition to a surface of a first substrate; and   bringing a surface of a second substrate into contact with the adhesive composition on the surface of the first substrate, thereby forming the laminate structure.   
     
     
         10 . The method for forming a laminate structure of  claim 1 , wherein mixing the isocyanate adhesive component and the isocyanate-reactive adhesive component occurs at a mole ratio of the NCO groups present in the isocyanate component to OH groups present in the isocyanate-reactive component is from 0.8:1.0 to 1.6:1.0. 
     
     
         11 . The method for forming a laminate structure of  claim 1 , wherein the first substrate and the second substrate are each independently selected from the group consisting of a wood material, a metallic material, a plastic material, a composite material, a paper material, a fabric material, and combinations of two or more thereof.