Thermosetting adhesives comprising a resin having azetidinium functional groups
View Patent ↗Thermosetting adhesives for use in e.g., particleboard or fiberboard, wherein the adhesives comprise a resin having azetidinium functional groups, can provide fast tack-building and curing, as well as ultimately excellent bonding characteristics. Preferably, the azetidinium-functional resin is formed from the reaction product of a polyamidoamine and epichlorohydrin.
1. A composition for preparing wood composites, said composition comprising (1) a thermosetting adhesive comprising predominantly a resin having azetidinium functional groups; (2) a wood element selected from the group consisting of wood flakes, wood strands, wood particles, wood layers, and mixtures thereof; and (3) urea as a cross-linking additive.
2. The composition of claim 1 herein said wood element is present in an amount from about 85% to about 98% by weight, on a dry solids basis, of said composition.
3. A wood composite comprising the composition of claim 1 , after said resin is cured.
4. The wood composite of claim 3 , wherein said wood composite is particleboard or fiberboard.
5. The wood composite of claim 1 , wherein the wood element is wood strands.
6. The wood composite of claim 1 , wherein the wood element is selected from the group consisting of wood flakes, wood strands, wood particles, and wood layers.
7. A method of making a wood composite, the method comprising:
(a) forming the composition of claim 1 into substantially the shape of said wood composite, and
(b) consolidating a shaped composition obtained in step (a) using heat and pressure into said wood composite.
8. The method of claim 7 , wherein the wood composite has an internal bond strength as measured by ASTM D 1037 between 100 psi and 300 psi.
9. The method of claim 8 , wherein the wood composite has an internal bond strength as measured by ASTM D 1037 between 120 psi and 250 psi.
10. A composition for preparing wood composites, said composition comprising (1) a thermosetting adhesive comprising predominantly a resin having azetidinium functional groups; (2) a wood element selected from the group consisting of wood flakes, wood strands, wood particles, wood layers, and mixtures thereof; and (3) urea as a cross-linking additive, wherein the thermosetting adhesive is substantially free of protein.
11. The composition of claim 10 , wherein said wood element is present in an amount from about 85% to about 98% by weight, on a dry solids basis, of said composition.
12. A wood composite comprising the composition of claim 10 , after said resin is cured.
13. The wood composite of claim 12 , wherein said wood composite is particleboard or fiberboard.
14. The wood composite of claim 12 , wherein the wood element is wood strands.
15. The wood composite of claim 10 , wherein the wood element is selected from the group consisting of wood flakes, wood strands, wood particles, and wood layers.
16. A method of making a wood composite, the method comprising:
(a) forming the composition of claim 10 into substantially the shape of said wood composite, and
(b) consolidating a shaped composition obtained in step (a) using heat and pressure into said wood composite.
17. The method of claim 16 , wherein the wood composite has an internal bond strength as measured by ASTM D 1037 between 100 psi and 300 psi.
18. The method of claim 17 , wherein the wood composite has an internal bond strength as measured by ASTM D 1037 between 120 psi and 250 psi.