Fiber-reinforced thermoplastic composite bonded to wood

• US 20020015819A1
• Filed: 06/07/2001
• Published: 02/07/2002
• Est. Priority Date: 06/09/2000
• Status: Active Grant

• Current Assignee: Fulcrum Composites, Inc.
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Miller, Faye J., Edwards, Christopher M., dʼHooghe, Edward L.
• Granted Patent: US 6,592,962 B2
• Time in Patent Office: Days
• US Class Current: 428/114
• CPC Class Codes: B27D 1/00 Joining wood veneer with any material; Forming articles thereby in conjunction with moulding of wood particles or fibres B27N3/06; Preparatory processing of surfaces to be joined, e.g. scoring
• CPC Class Codes: B27M 3/0053 using glue
• CPC Class Codes: B32B 27/04 as impregnant, bonding, or embedding substance not used
• CPC Class Codes: B32B 29/02 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 5/12 characterised by the relative arrangement of fibres or filaments of different layers, e.g. the fibres or filaments being parallel or perpendicular to each other
• CPC Class Codes: E04C 2/24 laminated and composed of materials covered by two or more of groups E04C2/12, E04C2/16, E04C2/20
• CPC Class Codes: E04C 3/18 with metal or other reinforcements or tensioning members
• CPC Class Codes: E04C 3/185 Synthetic reinforcements
• CPC Class Codes: Y10T 428/24058 including grain, strips, or filamentary elements in respective layers or components in angular relation
• CPC Class Codes: Y10T 428/24132 including grain, strips, or filamentary elements in different layers or components parallel
• CPC Class Codes: Y10T 428/249925 Fiber-containing wood product [e.g., hardboard, lumber, or wood board, etc.]
• CPC Class Codes: Y10T 428/249942 Fibers are aligned substantially parallel
• CPC Class Codes: Y10T 428/24995 Two or more layers
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer
• CPC Class Codes: Y10T 428/31982 Wood or paper
• CPC Class Codes: Y10T 428/31989 Of wood

Abstract

The present invention relates to wood that is reinforced with a fiber-reinforced thermoplastic composite that contains a plurality of substantially parallel continuous fibers impregnated with thermoplastic polymer having the following structural units:

where Z is S or O, and Z′ is S, O, N-alkyl or NH The invention is useful in a variety of applications including glue-laminated structures, laminated veneer lumber, reinforced I-beams, parallel strand lumber, reinforced particle board, and ladders. The use of thermoplastic polyurethane, particularly the high Tg thermoplastic polyurethane as the impregnating resin provides a means of recycling and reusing the reinforced lumber, as well as shaping the composite in ways that would be impossible using conventional fiber-reinforced thermoset composites.

Claims

1. A reinforced wood structure comprising an a) elongated multilamellar wood member having an uppermost lamina with an outer surface, a lowermost lamina with an outer surface, a longitudinal center, and a transverse center;

and b) a first elongated fiber-reinforced thermoplastic composite layer disposed

     1) through the longitudinal center of the wood member; and

     2) between and adherent to the major surfaces of two of the laminae, or adherent to the outer surface of the uppermost or lowermost lamina;

wherein the composite contains a plurality of substantially parallel continuous fibers impregnated with a thermoplastic polymer having the following structural units;

2. The reinforced wood structure of claim 1 wherein the first elongated fiber-reinforced thermoplastic composite layer is disposed distal from the transverse center in the direction of either the uppermost lamina or the lowermost lamina.

3. The reinforced wood structure of claim 2 wherein the first elongated fiber-reinforced thermoplastic composite layer is disposed between the uppermost lamina and a lamina adjacent to the uppermost lamina or between the lowermost lamina and a lamina adjacent to the lowermost lamina.

4. The reinforced wood structure of claim 1 wherein the first elongated fiber-reinforced thermoplastic composite layer is disposed at the outer surface of the lowermost lamina or the outer surface of the uppermost lamina.

5. The reinforced wood structure of claim 1 which further comprises a elongated second fiber-reinforced thermoplastic composite layer, wherein the first elongated fiber-reinforced composite layer is distal from the transverse center in the direction of the uppermost lamina, and the second elongated fiber-reinforced composite layer is distal from the transverse center in the direction of the lowermost lamina.

6. The reinforced wood structure of claim 5 wherein the first elongated fiber-reinforced thermoplastic composite layer is disposed between and adherent to the uppermost lamina and a lamina adjacent to the uppermost lamina, and the second elongated fiber-reinforced thermoplastic composite layer is disposed between the lowermost lamina and a lamina adjacent to the lowermost lamina, and wherein the fiber-reinforced thermoplastic composite layers extend through the length of the reinforced structure.

7. The reinforced wood structure of claim 1 wherein the polymer is a thermoplastic polyurethane.

8. The reinforced wood structure of claim 6 wherein the polymer is an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C. or a soft thermoplastic polyurethane resin having a T_g of less than 25°

C.

9. The reinforced wood structure of claim 8 wherein the polymer is an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C., wherein the composite is bonded to the laminae with an adhesive.

10. The reinforced wood structure of claim 9 wherein the composite is bonded to the laminae with phenol formaldehyde, phenol resorcinol formaldehyde, or MDI.

11. The reinforced wood structure of claim 8 wherein the polymer is an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C. that is prepared using a stoichiometric excess of a diisocyanate to form an overindexed resin.

12. The reinforced wood structure of claim 8 wherein the polymer is a soft thermoplastic polyurethane resin having a T_g of less than 25°

C.

13. The reinforced wood structure of claim 1 which is a reinforced glue-laminated or a reinforced laminated veneer lumber or plywood or a reinforcement for rails on a ladder or combinations thereof.

14. The reinforced wood structure of claim 1 wherein the lowermost surface of the reinforced wood structure is attached to the uppermost surface of a second reinforced wood structure through a web to form the shape of a composite reinforced I-beam.

16. The reinforced wood structure of claim 15 wherein each of the thermoplastic composite layers contain substantially parallel continuous fibers that are impregnated with a thermoplastic polyurethane resin having a T_g of less than 25°

C.

17. The reinforced wood structure of claim 15 wherein each of the thermoplastic composite layers contain substantially parallel continuous fibers that are impregnated with an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C.

18. The reinforced wood structure of claim 15 wherein one of the first and second thermoplastic composite layers contain substantially parallel continuous fibers that are impregnated with a thermoplastic polyurethane resin having a T_g of less than 25°

C. and the other of the first and second thermoplastic composite layers contain substantially parallel continuous fibers that are impregnated with an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C.

19. The reinforced wood structure of claim 15 wherein either the first or the second thermoplastic composite layer, or both the first and the second thermoplastic composite layer contain a blend of a thermoplastic polyurethane resin having a T_g of less than 25°

C. and an engineering thermoplastic polyurethane resin having a T_g of not less than 50°

C.

15. A reinforced wood structure comprising a) an elongated multilamellar wood member having an uppermost lamina with an outer surface, a lamina adjacent to the uppermost lamina, a lowermost lamina with an outer surface, and a lamina adjacent to the lowermost lamina;

b) a first elongated fiber-reinforced thermoplastic composite layer disposed through the length of the wood member and between and adherent to the uppermost lamina and the lamina adjacent to the uppermost lamina;

c) a second elongated fiber-reinforced thermoplastic composite layer disposed through the length of the wood member and between and adherent to the lowermost lamina and the lamina adjacent to the lowermost lamina;

wherein the composite layers each contain a plurality of substantially parallel continuous fibers impregnated with a thermoplastic polyurethane.

20. A reinforced wood structure comprising a fiber reinforced thermoplastic composite disposed onto wood or dispersed into wood particles, wherein the thermoplastic composite contains a plurality of substantially parallel continuous fibers impregnated with a thermoplastic polymer having the following structural units:

21. The reinforced wood structure of claim 20 wherein the fiber reinforced composite is in the form of strands of synthetic reinforcement dispersed in the wood particles, wherein the wood particles are adhered together in the form of particle board, oriented strand board, oriented strand lumber, fiberboard, or chipboard, and wherein the polymer is an engineering thermoplastic polyurethane having a T_g of not less than 50°

C.

22. The reinforced wood structure of claim 20 which is in the form of parallel strand lumber having strands aligned along an axis, wherein a) the fiber reinforced thermoplastic composite is in the form of strands aligned along the same axis as the lumber strands, and dispersed randomly through the parallel strand lumber structure, and b) the fibers are impregnated with a thermoplastic polyurethane.

24. The reinforced wood structure of claim 23 wherein the thermoplastic polymer is an engineering thermoplastic polyurethane having a T_g of not less than 50°

C.

26. The reinforced wood structure of claim 25 wherein a second sheet of fiber-reinforced thermoplastic polyurethane composite superposes and adheres to the other of the opposing major surfaces of the board, and wherein the reinforced wood structure is in the shape of a beam, a panel, or an I-beam.

27. The reinforced wood structure of claim 26 which contains an adhesive layer between the board and each of the fiber-reinforced thermoplastic polyurethane composite sheets.

28. The reinforced wood structure of claim 25 which contains no additional adhesive other than what is contained in the board.

30. The reinforced wood structure of claim 29 wherein the composite rods contain a thermoplastic polymer having the following structural units:

31. The reinforced wood structure of claim 30 wherein the thermoplastic polymer is an engineering thermoplastic polyurethane having a T_g of not less than 50°

C.

32. The reinforced wood structure of claim 31 wherein the lowermost lamina and the uppermost lamina each have slots or bores, and the tension reinforcement rods are imbedded into and adhering to the slots or bores of the lowermost lamina, and the compression reinforcement rods are imbedded into and adhering to the slots or bores of the uppermost lamina.

33. The reinforced wood structure of claim 31 wherein the synthetic tension and compression reinforcement rods do not extend through the length of the structure.

34. The reinforced wood structure of claim 31 wherein the the synthetic tension and compression reinforcement rods extend through the length of the structure.

36. The reinforced wood structure of claim 35 wherein one wood member has a plurality of slots or bores and a plurality of elongated fiber-reinforced thermoplastic composite rods embedded into slots or bores along the grain of the wood member.

37. The reinforced wood structure of claim 35 wherein one wood member has a slot or bore and a fiber-reinforced thermoplastic composite sheet disposed in the slot or bore along the grain of the wood member.

38. The reinforced wood structure of claim 35 which is elongated and multilamellar, wherein the sheets or rods are disposed through the multilamellar structure in a zig-zag fashion across the grain of the lamellae and through the length of the wood structure.

39. The reinforced wood structure of claim 35 wherein the composite rods contain a thermoplastic polymer having the following structural units:

40. The reinforced wood structure of claim 36 wherein the thermoplastic polymer is an engineering thermoplastic polyurethane having a T_g of not less than 50°

C.

23. A reinforced wood structure comprising a first fiber-reinforced thermoplastic composite flange and a second fiber-reinforced thermoplastic composite flange, each flange being bonded to a web to form a reinforced I-beam, wherein the fiber-reinforced thermoplastic composite flanges contain a plurality of substantially parallel continuous fibers impregnated with a thermoplastic polymer having the following structural units:

25. A reinforced wood structure comprising a) an elongated board having opposing major surfaces and b) a first sheet of fiber-reinforced thermoplastic polyurethane composite which superposes and adheres to one of the opposing major surfaces of the board, wherein the board is a particle board, oriented strand lumber, oriented strand board, fiberboard, or chipboard.

29. A reinforced wood structure comprising an elongated multilamellar wood member having a longitudinal center, a transverse center, a width center, and a plurality of elongated fiber-reinforced thermoplastic composite rods, at least two of which rods are tension reinforcement rods and at least two of which rods are compression reinforcement rods, wherein the tension reinforcement rods are disposed through the longitudinal center, and distal on either side of the width center and imbedded into and adhering to a lamina distal from the transverse center and proximal to the lowermost lamina of the multilamellar structure, and wherein the compression reinforcement rods are disposed through the longitudinal center, and distal from either side of the width center and imbedded into and adhering to a lamina distal from the transverse center and proximal to the uppermost lamina of the multilamellar structure.

35. A reinforced wood structure comprising at least one lamina having a fiber-reinforced thermoplastic composite sheet or at least one elongated fiber-reinforced thermoplastic composite rod embedded into at least one wood member.