Manufactured wood products and methods of production
A process of producing a manufactured wood product comprises providing a plurality of wood pieces having substantially an equilibrium moisture content; contacting the plurality of wood pieces with one or more additives under conditions for the additive(s) to soak into the wood pieces; applying a thermoplastic adhesive comprising a thermoplastic resin and a crosslinking agent to the wood pieces to form adhesive coated wood pieces; optionally heating the adhesive coated wood pieces to form heated adhesive coated wood pieces; assembling the adhesive coated wood pieces in a desirable configuration to form assembled adhesive coated wood pieces; compressing the assembled adhesive coated wood pieces in a press at a pressure and for a time sufficient to compact and compress the assembled wood pieces to force trapped air out of and mechanically deform the assembled adhesive coated wood pieces so that adjacent wood pieces conform to the shape of one another; crosslinking the thermoplastic adhesive to at least a critical crosslinking amount during the compression step to form an at least partially cured manufactured wood product, wherein the critical crosslinking amount is sufficient such that the at least partially cured manufactured wood product substantially maintains its compressed form and prevents the wood pieces expanding and returning to their initial state upon release of pressure in the compression step; removing the at least partially cured manufactured wood product from the press; and optionally, further curing the partially cured manufactured wood product to provide the manufactured wood product having substantially an equilibrium moisture content.
1. A process of producing a manufactured wood product comprising:
providing a plurality of wood pieces having substantially an equilibrium moisture content;
contacting the plurality of wood pieces with one or more additives under conditions for the additive(s) to soak into the wood pieces;
applying a thermoplastic adhesive comprising a thermoplastic resin and a crosslinking agent to the wood pieces to form adhesive coated wood pieces;
optionally heating the adhesive coated wood pieces to form heated adhesive coated wood pieces;
assembling the adhesive coated wood pieces in a desirable configuration to form assembled adhesive coated wood pieces;
compressing the assembled adhesive coated wood pieces in a press at a pressure and for a time sufficient to compact and compress the assembled wood pieces to force trapped air out of and mechanically deform the assembled adhesive coated wood pieces so that adjacent wood pieces conform to the shape of one another;
crosslinking the thermoplastic adhesive to at least a critical crosslinking amount during the compression step to form an at least partially cured manufactured wood product, wherein the critical crosslinking amount is sufficient such that the at least partially cured manufactured wood product substantially maintains its compressed form and prevents the wood pieces expanding and returning to their initial state upon release of pressure in the compression step;
removing the at least partially cured manufactured wood product from the press; and
optionally, further curing the partially cured manufactured wood product to provide the manufactured wood product having substantially an equilibrium moisture content.
2. The process according to claim 1 , wherein a veneer profile of each of the assembled wood pieces after compression is different to the veneer profile of each of the assembled wood pieces prior to compression.
3. The process according to claim 1 , wherein the adhesive coated wood pieces are preheated prior to assembling them in a desirable configuration and compressing.
4. The process according to claim 1 , wherein the crosslinked thermoplastic adhesive in the manufactured wood product has a glass transition temperature at or lower than the normal use temperature of the manufactured wood product.
5. The process according to claim 1 , wherein the thermoplastic resin is polyvinyl acetate or a hydrolyzed form thereof.
6. The process according to claim 5 , wherein the crosslinking agent is selected from the group consisting of aluminum chloride and p-toluene sulfonic acid.
7. The process according to claim 1 , wherein the assembled wood pieces are compressed to a pressure of about 4 to 20 MPa.
8. The process according to claim 1 , wherein the crosslinking is initiated by heating during the compression step.
9. The process according to claim 1 , wherein the at least partially-cured manufactured wood product is released from the mould whilst it is still warm.
10. The process according to claim 1 , wherein the wood for the wood pieces is selected from the group consisting of eucalypt, pine, red maple, Queensland maple, ash, aspen, walnut, oak, redwood, birchwood, mahogany, ebony, cherry wood, oregon, poplar and grasses.
11. The process according to claim 1 , wherein the one or more additives are selected from the group consisting of swell control agents, fungicides, insecticides, coloring agents, UV stabilizers, fillers, extenders, fire resistant agents, fire retardants, and fibers.
12. A process of producing a manufactured wood product comprising:
providing a plurality of wood pieces having substantially an equilibrium moisture content;
applying a thermoplastic adhesive comprising a thermoplastic resin and a crosslinking agent to the wood pieces to form adhesive coated wood pieces;
optionally heating the adhesive coated wood pieces to form heated adhesive coated wood pieces;
assembling the adhesive coated wood pieces in a mould or a press having a length, wherein a majority of the wood pieces are assembled with the fibre direction of the wood pieces substantially aligned with the length of the mould or press to form assembled adhesive coated wood pieces;
compressing the assembled adhesive coated wood pieces in a press in a direction and at a pressure and for a time sufficient to compact and compress the assembled wood pieces to force trapped air out of and mechanically deform the assembled adhesive coated wood pieces so that adjacent wood pieces conform to the shape of one another and alter the configuration of the wood pieces in the compressed block such that the wood pieces within the compressed block are in a different configuration to that of the assembled wood pieces;
crosslinking the thermoplastic adhesive to at least a critical crosslinking amount during the compression step to form an at least partially cured manufactured wood product, wherein the critical crosslinking amount is sufficient such that the at least partially cured manufactured wood product substantially maintains its compressed form and prevents the wood pieces expanding and returning to their initial state upon release of pressure in the compression step;
removing the at least partially cured manufactured wood product from the press; and
optionally, further curing the partially cured manufactured wood product to provide the manufactured wood product having substantially an equilibrium moisture content.
13. The process according to claim 12 , wherein a veneer profile of each of the assembled wood pieces after compression is different to the veneer profile of each of the assembled wood pieces prior to compression.
14. The process according to claim 12 , wherein the adhesive coated wood pieces are preheated prior to assembling them in a desirable configuration and compressing.
15. The process according to claim 12 , wherein the crosslinked thermoplastic adhesive in the manufactured wood product has a glass transition temperature at or lower than the normal use temperature of the manufactured wood product.
16. The process according to claim 12 , wherein the thermoplastic resin is polyvinyl acetate or a hydrolyzed form thereof.
17. The process according to claim 16 , wherein the crosslinking agent is selected from the group consisting of aluminum chloride and p-toluene sulfonic acid.
18. The process according to claim 12 , wherein the assembled wood pieces are compressed to a pressure of about 4 to 20 MPa.
19. The process according to claim 12 , wherein the crosslinking is initiated by heating during the compression step.
20. The process according to claim 12 , wherein the at least partially-cured manufactured wood product is released from the mould whilst it is still warm.