US-12617121-B2 - Part made from lignocellulosic material and method for producing such a part

Abstract

A part made from lignocellulosic material ( 10 ) is formed from a single sheet ( 11 ) of partially delignified lignocellulosic material impregnated with an impregnation polymer. The part ( 10 ) comprises at least one curved portion having a double curvature surface. The part made from lignocellulosic material is produced by a production method implementing a thermoforming step. Use in particular for producing wood veneer structures.

Inventors

• Raphaële THEVENIN
• Timothée BOITOUZET

Assignees

• SAS WOODOO

Dates

Publication Date

20260505

Application Date

20210319

Priority Date

20180920

Claims (20)

1. 1 . A composite material comprising a lignocellulosic material, wherein said lignocellulosic material is wood that is partially delignified, wherein said lignocellulosic material comprises a surface, wherein at least a portion of said surface is curved, wherein at least a portion of said curved surface is a dual curvature surface, and wherein said lignocellulosic material further comprises at least one filling compound.
2. 2 . The composite material of claim 1 , wherein said lignocellulosic material further comprises at least one accessory, wherein said at least one accessory is overmolded onto said lignocellulosic material using an overmolding polymer, and wherein said overmolding polymer is configured to adhere to at least a portion of said at least one filling compound.
3. 3 . The composite material of claim 1 , wherein said lignocellulosic material comprises at least one translucent portion, and wherein said at least one translucent portion has a light transmission coefficient of at least equal to 4%.
4. 4 . The composite material of claim 1 , wherein said lignocellulosic material comprises lignin, cellulose, and hemicellulose, wherein said lignin is between 10% to 60% by weight of said lignocellulosic material.
5. 5 . The composite material of claim 1 , wherein said at least one filling compound is from about 30% to about 80% by mass of a total mass of said lignocellulosic material.
6. 6 . The composite material of claim 1 , wherein said at least one filling compound comprise a thermoplastic polymer.
7. 7 . The composite material of claim 1 , wherein said lignocellulosic material has a thickness from about 0.1 mm to about 3 mm.
8. 8 . The composite material of claim 1 , wherein said curved portion has a curvature substantially identical in two orthogonal planes, with a radius of curvature less than 80 mm.
9. 9 . The composite material of claim 8 , wherein said curved portion has said radius of curvature substantially equal to 20 mm.
10. 10 . The composite material of claim 8 , wherein said curved portion has said curvature in a first plane, with said radius of curvature less than 10 mm.
11. 11 . The composite material of claim 8 , wherein said curved portion has said curvature in a first plane with said radius of curvature greater than or equal to 10 mm, and a curvature in a second plane, orthogonal to said first plane, with a radius of curvature less than 4 mm.
12. 12 . The composite material of claim 1 , wherein said at least one filling compound comprises an impregnation polymer.
13. 13 . The composite material of claim 12 , further comprising at least one accessory overmolded onto said surface.
14. 14 . The composite material of claim 13 , wherein said at least one accessory is molded in an overmolding polymer configured to adhere to said impregnation polymer.
15. 15 . The composite material of claim 14 , wherein said impregnation polymer is configured to hold cellulose fibers together in said lignocellulosic material and to provide the said cellulose fibers with a uniform and even sheathing.
16. 16 . The composite material of claim 14 , wherein said impregnation polymer is more flexible than lignin.
17. 17 . The composite material of claim 14 , wherein said impregnation polymer has a higher elastic modulus than lignin.
18. 18 . The composite material of claim 1 , wherein said wood is delignified to an extent of 40 to 90% by weight of lignin originally present in said wood.
19. 19 . The composite material of claim 1 , wherein said dual curvature surface is independent of a direction of fibers of said lignocellulosic material.
20. 20 . The composite material of claim 1 , wherein said composite material is configured to undergo greater bending, twisting, tension, and compressive deformation as compared to lignocellulosic material that is not partially delingified.

Description

CROSS-REFERENCE This application is a continuation of International Application Serial No. PCT/FR2019/052177, filed Sep. 18, 2019, which claims priority to French Patent Application No. 1858555, filed Sep. 20, 2018, which applications are incorporated herein by reference in their entirety for all purposes. The present invention concerns a part made from lignocellulosic material, a process for manufacturing such a part and a process for transforming such a part made from lignocellulosic material. The use of parts made of lignocellulosic material, and in particular of wood, is greatly valued for the natural aesthetics, the warm color and the specific feel of wood. It enables structures adorned with a wood cladding part to be ennobled. Thus, wood cladding is currently much sought after for the furniture, the interior architecture, and the adornment of automotive vehicle interiors, or in the aeronautical or nautical field. It has also been sought to use wood cladding of diverse forms, by for example creating curved surfaces by shaping a plate of wood. However, wood cladding is fragile and has tear or break lines when it is shaped and strongly curved. A wood part is for example known, which is described in document US2008/0020222, formed from a wood plate, of thickness comprised between 0.1 and 1 mm, and impregnated with a resin in order for provide a certain flexibility for the wood plate. This plate of wood may thus be deformed to obtain a wood part of chosen three-dimensional shape. Document US2008/0020222 describes in particular different embodiments in which several wood plates, impregnated with resin, are stacked and bonded to each other before being deformed through implementation of a hot pressing process. Two superposed wood plates, with their grain respective direction perpendicular to each other, may thus be deformed to constitute a loudspeaker member, with a central planar portion and a peripheral portion in the form of a flared frustoconical shape. However, the superposition of wood plates to form a deformable wood part necessarily leads to obtaining parts of high thickness. The weight of such parts is thereby increased, and this may discourage their use in particular in the field of automotive or aeronautical interiors. Furthermore, particular care must be given on deforming wood plates superposed by hot pressing, in order to preserve the integrity of the part formed from wood plates that are stacked and bonded to each other. As the behavior of wood is not predictable when it is shaped, the rejection rate is very high, increasing the final cost of the deformable wood part. The present invention is directed to providing a part made from lignocellulosic material and an associated manufacturing process that make it possible to obtain parts made of lignocellulosic material that mitigate the aforementioned drawbacks. To that end, according to a first aspect, the present invention concerns a part made from lignocellulosic material, formed from a single sheet of lignocellulosic material that is partially delignified and impregnated with an impregnation polymer, said part comprising at least one curved portion having a surface of dual curvature. The Applicant has observed that by preparing a part from a lignocellulosic material that is partly delignified and impregnated with a polymer, is was possible to produce a part having at least one portion of dual curvature from a single sheet. In the partly delignified lignocellulosic material, the lignin (a chemical compound unevenly distributed between the cellulose fibers of the lignocellulosic material) is replaced by the impregnation polymer. The latter plays a reinforcing role, holding the cellulose fibers together and providing the cellulose fibers with uniform and even sheathing. When it is heated, the impregnation polymer is more flexible than the lignin it replaces, while having a sufficiently high Young's modulus to preserve sheathing and a mechanical link between the cellulose fibers. The sheet of lignocellulosic material that is partially delignified and impregnated with a polymer is thus mechanically reinforced and can undergo greater bending, twisting, tension and compression deformations. It is thus possible to obtain very varied geometric shapes, which cannot be attained with sheets of untreated wood. It is thus possible to obtain a part made from lignocellulosic material, formed from a single sheet and having a surface of dual curvature. The part may thus take on a three-dimensional shape that is very original for a part made from lignocellulosic material, for example, a hyperbolic paraboloid surface, a hemispherical shape, a shell shape, flared cone, tapered cylinder, and more generally any type of warped surface (non-developable surface). Shaping with a single sheet makes it possible to obtain a very light part, without crossing being generated of lignocellulosic material fibers by superposition of wood plates in the prior art. The part made fro