Decorative sheet or molding and process for its production

• US 20020155297A1
• Filed: 02/08/2002
• Published: 10/24/2002
• Est. Priority Date: 02/14/2001
• Status: Active Grant

• Current Assignee: Trespa International B.V. (Broadview Holding BV), Trespa International B.V.H.
• Original Assignee: Trespa International B.V. (Broadview Holding BV)
• Inventors: Schuren, Geer, Van Der Vorst, Chris
• Granted Patent: US 6,926,954 B2
• Time in Patent Office: Days
• US Class Current: 428/413
• CPC Class Codes: B32B 21/02 the layer being formed of fibres, chips, or particles , e.g. MDF, HDF, OSB, chipboard, particle board, hardboard
• CPC Class Codes: B32B 21/08 of synthetic resin
• CPC Class Codes: B32B 27/04 as impregnant, bonding, or embedding substance not used
• CPC Class Codes: B44C 5/043 containing wooden elements
• CPC Class Codes: B44C 5/0461 used as wall coverings
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/16 Addition or condensation polymers of aldehydes or ketones according to C08L59/00 - C08L61/00; Derivatives thereof
• CPC Class Codes: C08L 97/02 Lignocellulosic material, e.g. wood, straw or bagasse manufacture of articles made from lignocellulosic material by dry processes B27N
• CPC Class Codes: Y10T 428/249925 Fiber-containing wood product [e.g., hardboard, lumber, or wood board, etc.]
• CPC Class Codes: Y10T 428/249941 Fiber is on the surface of a polymeric matrix having no embedded portion
• CPC Class Codes: Y10T 428/251 Mica
• CPC Class Codes: Y10T 428/253 Cellulosic [e.g., wood, paper, cork, rayon, etc.]
• CPC Class Codes: Y10T 428/257 Iron oxide or aluminum oxide
• CPC Class Codes: Y10T 428/258 Alkali metal or alkaline earth metal or compound thereof
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31949 Next to cellulosic

Abstract

A decorative sheet or a molding, in particular suitable for indoor or outdoor applications on buildings, is in each case composed of a single- or multi-layer core, monolaterally or bilaterally laminated with decorative layer(s) The core layer(s) comprise(s) wood fibers, cellulose fibers, or timber sawdust products and also an organic or inorganic filler material, and a hot-curing resin. The particle size of the filler material is smaller than the thickness of the fibers or of the timber sawdust products in the core layer(s). These core layer(s) are composed of from 15 to 80% by weight of fibers or of timber sawdust products, from 10 to 75% by weight of filler material, and from 10 to 50% by weight of resin, based in each case on the total weight of the core layer(s).

Claims

1. A decorative sheet or a molding, in particular for indoor or outdoor applications on buildings, made from a monolaterally or bilaterally decorative-layer-laminated, pressed single- or multilap core layer made from wood fibers, cellulose fibers, a mixture of wood fibers and cellulose fibers, or from timber sawdust products, where the fibers or the timber sawdust products have been impregnated with a resin as binder and are surrounded by the hot-curing binder, wherein the core layer comprises a filler material whose particle size is smaller than the thickness of the fibers or of the timber sawdust products.

2. The decorative sheet or the molding as claimed in claim 1, wherein the core layer is composed of from 15 to 80% by weight of fibers or of timber sawdust products, from 10 to 75% by weight of filler material, and from 10 to 50% by weight of resin, based in each case on the total weight of the core layer.

3. The decorative sheet or the molding as claimed in claim 1, wherein the core layer encompasses from 25 to 75% by weight of fibers or of timber sawdust products, from 20 to 50% by weight of filler material, and from 15 to 35% by weight of resin, based in each case on the total weight of the core layer.

4. The decorative sheet or the molding as claimed in claim 1, wherein the filler material is thermally stable up to 200°

C. and neither hydrolyzable nor hygroscopic, and is composed of inorganic or organic material.

5. The decorative sheet or the molding as claimed in claim 1, wherein the particle size of the filler material is in the range from 1 to 250 μ

m, in particular from 5 to 50 μ

m.

6. The decorative sheet or the molding as claimed in claim 1, wherein the filler material is selected from the group consisting of inorganic materials encompassing, inter alia, talc, chalk, dolomite, aluminum hydroxide, magnesium hydroxide, barium sulfate, pearlite, diatomite, mica, calcium carbonate, and mixtures of these.

7. The decorative sheet or the molding as claimed in claim 1, wherein the filler material is composed of organic materials, such as ground residues of HPL sheets, sawdust produced from HPL sheets when the sheets are cut, ground used HPL sheets, ground residues of timber sawdust products, wood fibers, cellulose fibers.

8. The decorative sheet or the molding as claimed in claim 1, wherein the water content of the core layer prior to press-molding to give a prepreg is from 0.5 to 10% by weight, in particular from 1.5 to 2.5% by weight, based on the total weight of the core layer.

9. The decorative sheet or the molding as claimed in claim 1, wherein the water absorption of the sheet decreases as the content of the filler material rises, at a resin content of from 20 to 25% by weight.

10. The decorative sheet or the molding as claimed in claim 9, wherein the volume swelling of the sheet decreases as inorganic filler content rises, at a resin content of from 20 to 25% by weight.

11. The decorative sheet or the molding as claimed in claim 9, wherein the volume swelling of the sheet remains almost constant as organic filler content rises, at a resin content of from 20 to 25% by weight.

12. The decorative sheet as claimed in claim 9, wherein the flexural strength of the sheet with up to 50% by weight content of filler material is at most 20% lower than the flexural strength of a sheet in whose core layer no filler material is present.

13. An article comprising the sheet or the molding of claim 1 for external cladding of buildings in the form of a curtain facade, of a panel screening a wall or roof, or of cladding for a balcony, or of a parapet panel or apron panel, or else for the internal lining of walls or furniture, or of wet-rooms or laboratory equipment.

15. The process as claimed in claim 14, wherein, in the first step, cellulose fibers, wood fibers, a mixture of wood fibers and cellulose fibers, or timber sawdust products are mixed with the resin, and wherein filler material is admixed in a second step.

16. The process as claimed in claim 14, wherein the free water content of the mixture made from cellulose fibers, wood fibers, a mixture of wood fibers and cellulose fibers, or timber sawdust products, filler material, and resin is reduced to 0.5-10% by weight, in particular 1.5-2.5% by weight, based on the total weight of the mixture, by drying the mixture prior to the precompaction of the layers.

17. The process as claimed in claim 14, wherein the press-molding of the monolaterally or bilaterally with decorative layer(s) laminated combined layers is undertaken at a temperature of at least 120-180°

C. with a pressure of from equal/higher 65 to 100 bar.

14. A process for producing a sheet or a molding, in which one or more mechanically precompacted layers made from cellulose fibers, wood fibers, a mixture of wood fibers and cellulose fibers, or from timber sawdust products, enclosed by a hot-curing resin, having been placed one upon the other, are press-molded to one another and to one or more decorative layer(s) in contact with one or both surfaces of the combined layers, using heat, where the resin is cured, which comprises, prior to the precompaction of the layer(s) in a first step mixing filler material with the fibers or timber sawdust products or with the resin, and comprises, in a second step, admixing resin, fibers or timber sawdust products.