Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/02—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/06—Making particle boards or fibreboards, with preformed covering layers, the particles or fibres being compressed with the layers to a board in one single pressing operation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27D—WORKING VENEER OR PLYWOOD
  • B27D1/00—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring

Definitions

• the present invention relates to a woody board, which has a sufficient mechanical strength as a woody material and which has a smooth surface.
• a wood powder and woody fibers are well known in this technical field. Briefly, the former is one to be obtained by finely pulverizing wood like sawdust; and the latter are ones to be obtained by disintegrating wood into fibers. Wood chips in this case are also known, which are obtained by shaving or cutting a wood bar from the top end thereof, with the bar being rotated in such a way that a pencil is shaven, into chips each having a size of about 1.5 mm or less as the thickness, about 30 mm or less as the width and about 100 mm or less as the length. Examples of molded boards made of such woody material will be mentioned.
• simplex boards made of a wood powder there is known a particle board; as examples of simplex boards made of woody fibers, there are a hard board, a middle density fiber board (MDF) and an insulation board; and as examples of simplex boards made of wood chips, there are a strand board and an oriented strand board (OSB).
• MDF middle density fiber board
• OSB oriented strand board
• the latter method also has a troublesome problem that the mechanical strength of the resulting laminate board is low, because of the following reasons.
• an MDF could not be thinner than 3 mm, as too thin MDF sheets would curve owing to insufficiency of the strength of them. Therefore, even when an thinnest MDF sheet having a thickness of 3 mm is laminated to the both surfaces of a substrate woody material by the method, the resulting plywood is to have a total thickness of the both laminated MDF's of being 6 mm, so that the mechanical strength of the plywood is lowered relative to the thickness.
• the resulting plywood laminate is also disadvantageous as it is often warped.
• One object of the present invention is to provide a woody board, which has good physical properties with respect to the mechanical strength, the surface smoothness and the screw-drawing resistance value and which is prepared at a low manufacture cost.
• Another object of the present invention is to provide a method of preparing a woody board having a good surface smoothness and a sufficient mechanical strength.
• Still another object of the present invention is to provide a method of preparing a woody material of a coniferous tree material, which has a woody substrate of a coniferous tree woody material and which has a smooth surface with neither warp nor reduction of the mechanical strength.
• a woody board which is characterized in that said woody board uses a coniferous tree material of a coniferous tree plywood or coniferous tree LVL as a woody substrate and is formed with molded layer of woody material such as wood powder or woody fibers on one surface or both surfaces of the woody substrate.
• a coniferous tree material of a coniferous tree plywood or coniferous tree LVL as a woody substrate
• molded layer of woody material such as wood powder or woody fibers
• the present invention provides a method of preparing a woody board in which a woody substrate of coniferous tree LVL, coniferous tree plywood or the like is sandwiched between molded layers of a woody material such as a wood powder or woody fibers to form a woody board, and the method is carried out by first forming a woody material layer of a wood powder or woody fibers, as previously blended with an adhesive by spraying, then putting an LVL, plywood or the like thereon, and thereafter further forming said woody material layer thereon, whereupon all the piled-up layers are integrated by hot-pressing under pressure and heat.
• the coniferous tree plywood or LVL may be either in the form of a previously shaped one or in the form of a combination of plural veneers as merely piled up prior to being shaped into a plywood.
• the raw material of a board to be used in the present invention which comprises a woody material of a wood powder or woody fibers and an adhesive, may be one to be specifically prepared for repairing or may also be any general raw material for ordinary particle boards or fiber boards. Therefore, as a woody material for use in the present invention, a wood powder as well as fine wood chips to be prepared by finely pulverizing a wood material and small wood flakes to be obtained by cutting or shaving a wood material, and also shaped bodies to be formed by shaping such a wood powder, wood chips or wood flakes under pressure, and fibrous materials of them may be employed.
• the particle size of the wood powder as well as the size of the wood flakes may well be selected and determined in accordance with the intended surface smoothness of the final product of a woody board.
• MDF middle density fiber board
• the hot-pressing method of forming the woody board of the present invention may be either a hot plate-pressing method or a hot roll-pressing method.
• a hot plate or a hot roll may be applied to the materials to be laminated and molded under pressure, or a hot steam may also be applied thereto under pressure.
• the materials to be laminated and molded may previously be heated by blowing a hot steam thereto or by heating them in an oven, and the thus pre-heated materials may be pressed and integrated to obtain the intended woody board.
• a hot-gluing adhesive is used since the molding materials and laminates are pressed under heat to give an integrated woody board.
• Any conventional adhesives well known in this technical field such as phenolic resins and melamine resins, can be used for the purpose.
• thermosetting and water-proofing resins such as melamine resins are selectively used, the water-proofness of the molded board layers is advantageously improved.
• the thickness of the molded layer of a woody material may well be increased or decreased in accordance with the object of the woody board to be prepared. For instance, where the object of the board is to have merely a smooth surface, the layer of the molded layer may be thin to have a thickness of from 1 to 2 mm after shaped. On the other hand, where the surface of the woody material is to be further cut and machined, the thickness may be approximately from 5 to 10 mm.
• the molded layer of a woody material is put on the both surfaces of the substrate both in the same thickness, in view of the balance to be formed.
• the thickness of the molded layer of a woody material may well be much similar than that of the substrate, it is possible to prepare a one side-molded woody board with no warp and it is also possible to prepare a both sides-molded woody board where the both molded layer on the both surfaces each have a different thickness.
• the woody material for the molded layer may be either in the form of an already cold-pressed sheet or an adhesive-applied but not cold-pressed sheet. In the latter case, the woody material is in the form of a compound of a wood powder or woody fibers as already blended with an adhesive. If desired, the woody material for molded layer may also be in the form of a sheet to be obtained by pre-hot-pressing the woody material along with an adhesive. In the case, a two-stage polymerizing resin may advantageously be used as an adhesive. Precisely, the respective woody material layers may be pre-shaped by the first hot-pressing and thereafter they are integrated by the next hot-pressing.
• a coniferous tree plywood or a coniferous tree LVL is preferred in view of the object of the present invention.
• An adhesive may be coated to such a coniferous tree molded to give a molded coniferous tree plywood or LVL.
• the resulting confierous tree plywood or LVL layer can be used as a molded substrate.
• the woody substrate may also be in the form of a sheet as prepared by hot-pressing the corresponding plywood or LVL piled strips, or in the form of a cold-pressed piled strips prior to hot-pressing, or in the form of an adhesive-applied but not cold-pressed layer of veneers or laminars. Anyhow, all the woody substrate materials may be hot-pressed with putting other raw board materials thereon to give the woody board of the present invention.
• the mechanical strength of the resulting MDF board is lowered so that the flexibility of the board is large, as mentioned above. Therefore, a satisfactory board, e.g., large-sized board, could not be formed of such an MDF.
• the thickness thereof is generally up to 3 mm. Because of the reasons, a thin and strong woody material could not be obtained by molding of MDF layers.
• a woody substrate is a coniferous tree LVL
• a woody material layer is formed on one or both surfaces of the woody substrate so that the board layer may well have a thickness of 3 mm or less in order to obtain the intended woody board.
• the woody board to be obtained by the present invention may have a smooth surface and a high mechanical strength.
• an extremely thin woody material molded layer may be formed on the surface(s) of the woody laminate substrate. Therefore, even though the coat is formed on only one surface of the substrate to form a one surface-molded board, the resulting one surface-molded board is advantageously free from warping.
• a melamine resin adhesive was applied to five sheets of Douglas fir rotary veneer each having a thickness of 2.5 mm in the direction perpendicular to the fibrous direction of each sheet by a known method of forming a conventional plywood, and the thus adhesive coated sheets were cold-pressed to form a woody substrate.
• the veneers of constituting the surfaces of the substrate had 25 knots each having a diameter of approximately 35 mm in the area of 1850 mm x 980 mm.
• wood of Douglas fir rotary veneer was finely pulverized, and the resulting wood powder was blended with 12 % of a melamine resin adhesive by spraying to prepare an MDF material. This was put in an iron plate in a thickness of 15 mm, and the previously cold-pressed plywood was put thereover. Further, the wood powder was put over the plywood in a thickness of 15 mm.
• a decorative veneer of Douglas fir having a thickness of 0.6 mm was stuck to one surface of the woody board to give a decorative plywood having an extremely flat and smoothly finished surface.
• the woody board thus obtained warped with the smooth surface being convex in such a condition that the arrow height was 1.5 mm to the length of 1850 mm.
• the warp of such a degree has heretofore been said to cause no problem in practical use of the board, and the board stood the product standard test.
• Example 2 In accordance with the same process as in Example 1, except that the thickness of the rotary veneer of Douglas fir, which was 2.5 mm in Example 1, was varied to 1.7 mm, a laminate substrate was prepared. Both surfaces of the substrate were coated with an MDF having a thickness of 3 mm, in place of the woody material as used in Example 1. The thus piled-up woody layers were then hot-pressed in the same way as in Example 1 to obtained a woody material having the same thickness as that obtained in Example 1.
• the thus prepared woody material had a low and insufficient mechanical strength relative to the thickness thereof and therefore it was not suitable to practical use.
• the mechanical strength values of the product are shown in Table 1 below.
• Example 2 The same process as in Example 1 was repeated, except that the thickness of the rotary veneer of Douglas fir rotary veneer, which was 2.5 mm in Example 1, was varied to 2.9 mm and that the woody material was not used, but a coniferous tree plywood was only used. Accordingly, a decorative plywood having almost the same thickness as that of the product of Example 1 was prepared.
• the decorative plywood thus prepared had many knots and cracks, and the outward appearance thereof did not stand the test.
• substantially warp-free woody boards and decorated boards which have smooth and flat surfaces as their outward appearance and which have a sufficient mechanical strength are obtained by the method of the present invention, and the industrial advantage of the present invention is noticeable.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Veneer Processing And Manufacture Of Plywood (AREA)
• Laminated Bodies (AREA)

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Publications (3)

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Cited By (8)

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Citations (6)

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• 1990
  • 1990-06-19 JP JP2160399A patent/JP3038488B2/ja not_active Expired - Fee Related
• 1991
  • 1991-06-14 KR KR1019910009849A patent/KR0183985B1/ko not_active IP Right Cessation
  • 1991-06-18 CA CA002044865A patent/CA2044865C/fr not_active Expired - Lifetime
  • 1991-06-19 EP EP91110039A patent/EP0462586B1/fr not_active Expired - Lifetime
  • 1991-06-19 DE DE69131547T patent/DE69131547T2/de not_active Expired - Lifetime
  • 1991-06-19 AU AU79149/91A patent/AU653529B2/en not_active Expired
  • 1991-06-19 NZ NZ23861691A patent/NZ238616A/en not_active IP Right Cessation

Patent Citations (6)

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