EP0657257B1 - Composite à base de bois - Google Patents

Composite à base de bois Download PDF

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Publication number
EP0657257B1
EP0657257B1 EP94810403A EP94810403A EP0657257B1 EP 0657257 B1 EP0657257 B1 EP 0657257B1 EP 94810403 A EP94810403 A EP 94810403A EP 94810403 A EP94810403 A EP 94810403A EP 0657257 B1 EP0657257 B1 EP 0657257B1
Authority
EP
European Patent Office
Prior art keywords
fibre
wood
mat
formaldehyde resin
thermosetting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94810403A
Other languages
German (de)
English (en)
Other versions
EP0657257A1 (fr
Inventor
Suezone Chow
David Timothy Martin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canadian Forest Products Ltd
Original Assignee
Canadian Forest Products Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canadian Forest Products Ltd filed Critical Canadian Forest Products Ltd
Publication of EP0657257A1 publication Critical patent/EP0657257A1/fr
Application granted granted Critical
Publication of EP0657257B1 publication Critical patent/EP0657257B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
    • E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
    • E04C2/24—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products laminated and composed of materials covered by two or more of groups E04C2/12, E04C2/16, E04C2/20
    • 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
    • B27N7/00—After-treatment, e.g. reducing swelling or shrinkage, surfacing; Protecting the edges of boards against access of humidity
    • B27N7/005—Coating boards, e.g. with a finishing or decorating layer

Definitions

  • This invention relates to a method of finishing a wooden surface.
  • FR-A-2 667 264 discloses such a method.
  • solid rough wooden core layer is covered with a scrim and a mixture of wooden fibres and adhesive in a heated press.
  • a saw mill cutting lumber to a nominal thickness of one inch will obtain actual thicknesses ranging from 0.5 to 1.25 inches.
  • Laminating such pieces to produce larger members for structural or decorative applications requires that the pieces be planed to uniform thickness with smooth surfaces. Failure to finish in this way will prevent the application of an adhesive or the formation of a durable bond.
  • the cost of processing the wood to obtain the requisite surface and the amount of waste generated are both high.
  • the processing of nominal one inch lumber to meet the adhesion requirements can result in losses of wood fibre in the range 25 to 40 percent by weight of the original wood.
  • the present invention seeks to provide a method of avoiding the above processing and thus the consequent waste.
  • the invention seeks to avoid the waste involved in the above processing and is a method of finishing a wooden surface, said method being characterized in that the mixture comprises a thermosetting adhesive, and a prefabricated needled mat comprising in addition a wooden fibre, a thermosetting resin and at least one other fibre having a longer strand length than the wood fibre.
  • the present invention is useful in finishing any wooden surface, its preferred application is in the finishing of a rough wooden surface, such as would result from a saw cut.
  • thermosetting resin is preferably phenol-formaldehyde.
  • other useful thermosetting adhesives include phenol-resorcinol-formaldehyde resin, resorcinol-formaldehyde resin, urea-formaldehyde resin, melamine-urea-formaldehyde resin and melamine-formaldehyde resin.
  • the wood fibre of the mat may be either mechanically refined without delignification or chemically refined with some degree of delignification.
  • the wood fibre may be derived from virgin or recycled, including post-consumer, wood.
  • the fibre is treated with the thermosetting resin and dried.
  • the dried, resinated wood fibre is formed into a mat in an air-laid process.
  • This mat is intimately mixed with another mat composed of at least one other fibre.
  • That fibre may be a synthetic material such as polyester or a polyolefin, or a natural material such as hemp, flex jute or kenaf.
  • the two mats are blended together by passing them through a toothed roller.
  • a fine synthetic scrim is fed onto the bottom of blended mat as a carrier and the entire mat-scrim assembly is needled to produce a string fibre mat with mechanically interlocked wood and synthetic fibre.
  • the combined fibre mat is placed on top of lumber, for example nominal one inch thick pieces of spruce - pine - fir (SPF) as commonly produced in Western Canada.
  • a layer of the thermosetting adhesive is applied between the two layers.
  • the mat is transferred to a heated platen press which bonds the materials of the mat and bonds the mat to the lumber substrate.
  • the pressing conditions are chosen such that compression of the lumber substrate is minimized while the fibre layer is compressed to a density of up to 1.2 g/cm 2 .
  • thermosetting adhesive layer containing phenol-formaldehyde, phenol-resorcinol-formaldehyde, resorcinol-formaldehyde, urea-formaldehyde, melamine-urea-formaldehyde or melamine-formaldehyde resin but preferably comprising a) a commercially available phenol-formaldehyde resole resin, b) wood flour, c) wheat flour, d) soda ash and e) water, is applied at a rate of about 0.244-0.489 kg/m 2 to both faces of the lumber.
  • a pre-formed mat consisting of a) refined wood fibre (80-90%); b) phenol-formaldehyde or urea-formaldehyde thermosetting resin (4-9%); and c) polyester, thermoplastic or natural fibre (4-12%).
  • the combined five element construction comprising from top to bottom, fibre mat, adhesive, lumber, adhesive, fibre mat is consolidated and cured in a flat platen hot press.
  • the platens are heated to a temperature in the range 150-250°C.
  • the platens are closed at a rate of 20-40 mm/sec to a separation of 140-240% of the final thickness of the product and at a rate of 1-10 mm/sec until the maximum pressure is obtained.
  • the final position is chosen so as to allow fibre layer thicknesses of 2-6 mm.
  • the maximum pressure exerted on the board is in the range 20-30 kg/cm 2 .
  • the total press time, daylight to daylight ranges from 2-3.5 minutes and includes from 0-4 breathing cycles of 5 to 15 seconds, which prevents steam pressure from causing inter- or intra-laminar rupturing of the elements and are achieved by opening and re-closing the press.
  • the platens are separated to allow the finished boards to be removed from the press.
  • the boards are subsequently stacked together so as to cool slowly to room temperature and allow complete curing of the adhesive.
  • the platens were closed at a rate of 27 mm/sec to a separation of 45 mm and then at a rate of 3 mm/sec to a pressure of 24 kg/cm 2 .
  • the minimum separation of the platens was governed by a pair of aluminum bars of 19.0 mm thickness on the sides of the bottom platen.
  • a timer was started. The pressure was maintained to an elapsed time of 60 seconds before the platen separation was increased to allow venting of the steam pressure. This opening and the subsequent closing was completed at an elapsed time of 65 seconds.
  • the pressure was maintained again at 24 kg/cm 2 until an elapsed time of 90 seconds when the pressure was again removed and reapplied.
  • the target thickness of the fibre layer in the finished product was 2.5 mm. This corresponds to a density of that layer of ca. 1.0 g/cm 3 .
  • Example 1 described the preparation of the new composite using smooth, planed lumber as the substrate.
  • One of the main advantages of this invention is the ability of the fibre mat to mould to the shape of the lumber substrate and effectively mask any thickness variations or extreme roughness. It is a desirable feature of the invention that large variations in the thickness of the substrate can be tolerated without impairing the bonding at the solid wood/fibre interface.
  • Lumber thickness variations such as those described in Example 2 are compensated for in this invention by the mouldability of the fibre mat which allows the fibre to fill depressions and voids in the lumber surface. As a result, the density of the fibre layer is lower in density in such areas.
  • each of these fibre areas there is also some density variation as the density in the middle of the region is lower than the density either at the lumber interface or the surface that would have been next to the platen during pressing.
  • the density profile of the fibre layers changes as the depth of the depressions becomes greater (Samples 50x, 60x and 70x). In these cases, the average density of the fibre regions lowers considerably on the side containing the depression. In fact in the extreme cases, the density of the fibre layer is lower than that of the lumber. However, there are also some noticeable changes in the fibre layer on the side opposite to the depression. In this case there is also a lowering in average density and the density profile across the fibre layer becomes more pronounced. Therefore, the conclusion is that both fibre layers assist in masking a defect on one of the faces.
  • Another advantage of this invention is that the average density is considerably lower than other wood-based composites such as particleboard or medium density fibreboard. This is advantageous from the point in view of the user (e.g. better machinability and lower shipping costs) and the producer (e.g. increased fibre utilization).
  • the composite does have a high surface density of up to 1.0 g/cm 3 .
  • Example 1 The procedure of Example 1 was repeated several times with the following changes being made: 1) the total time in the hot press was varied from 1.75 to 2.75 minutes and 2) the open assembly time (i.e. the amount of time from the application of the adhesive to the lumber substrate and the mating of the fibre mat to that layer) was varied from 0 to 20 minutes.
  • the pressed samples were tested for inter-laminar adhesion using ASTM D 2339-82, Standard Test Method for Strength Properties of Adhesives in Two-Ply Wood Construction in Shear by Tension Testing. The samples were tested for shear values and position of failure (either glueline, wood or fibre).
  • the resulting billet was pressed under the same conditions as those used for the polyester containing mats.
  • Test methods were taken from ASTM D1037-87, Standard Methods of Evaluating the Properties of Wood-Base Fibre and Particle Panel Materials and ASTM D143-83, Standard Methods of Testing Small Clear Specimens of Timber.
  • the Screw Withdrawal test was adapted for use with 19 mm material by prorating the lead hole and screw insertion depths to 12.75 mm.
  • the material prepared as described in Example 1 was compared with other wood composite materials such as a) hardwood plywood b0 a composite comprised of a softwood veneer crossband laminate over a particleboard core c) particleboard, and d) medium density fibreboard. These samples were obtained from commercial supplies and are believed to be representative of products generally used in the marketplace.
  • Table 4 Physical Properties of Wood Based Composites Type Density (g/cm ⁇ 3) Modulus of Rupture (psi) Modulus of Elasticity (psi) Edge Screw Retention (lb) Hardwood Plywood 0.523 6430 580800 140 Particleboard/Veneer Composite 0.585 4160 306300 90 Paticleboard 0.720 1700 327800 80 Medium Density Fibreboard 0.746 4990 455600 130 Oriented Standboard 0.649 2420 325600 150 Present Invention 0.538 7690 685300 200

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Architecture (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Forests & Forestry (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Laminated Bodies (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Claims (17)

  1. Procédé de finition d'une surface en bois, ledit procédé comprenant l'application sur la surface d'un mélange comprenant une fibre de bois adhésive et l'application de chaleur et de pression pour coller les composants l'un à l'autre et à la surface en bois, caractérisé en ce que le mélange comprend un adhésif thermo-formable, et un mat préfabriqué comprenant en plus une fibre en bois, une résine thermo-formable et au moins une autre fibre ayant une longueur de fil plus longue que celle de la fibre de bois.
  2. Procédé selon la revendication 1 selon lequel l'adhésif thermo-formable est une résine formaldéhyde phénolique.
  3. Procédé selon la revendication 1 selon lequel l'adhésif thermo-formable est choisi dans un groupe comprenant de la résine résorcine-formaldéhyde phénolique; de la résine résorcine-formaldéhyde; de la résine urée-formaldéhyde; de la résine mélamine-formaldéhyde et de la résine mélamine-formaldéhyde.
  4. Procédé selon la revendication 1 selon lequel l'adhésif thermo-formable comprend une résine formaldéhyde-phénolique, de la farine de bois, de la farine de froment, de la soude à l'ammoniaque de commerce et de l'eau.
  5. Procédé selon l'une des revendications 1 à 4 selon lequel l'adhésif thermo-formable est appliqué à la surface en bois à une quantité d'environ 0.244 à 0.489 kg/m2.
  6. Procédé selon l'une des revendications 1 à 5 selon lequel la fibre de bois du mat est une fibre de bois épurée.
  7. Procédé selon l'une des revendications 1 à 6 selon lequel la résine thermo-formable du mat est une résine formaldéhyde-phénolique ou une résine urée-formaldéhyde.
  8. Procédé selon l'une des revendications 1 à 7 selon lequel au moins une autre fibre a une longueur comprise dans la fourchette de 50 à 100 mm.
  9. Procédé selon la revendication 8 selon lequel au moins une autre fibre est une fibre synthétique choisie parmi les fibres polyester et polyoléfine.
  10. Procédé selon la revendication 8 selon lequel au moins une autre fibre est du chanvre ou du lin.
  11. Procédé selon la revendication 1 selon lequel la fibre de bois et au moins une autre fibre sont intimement mélangées.
  12. Procédé selon l'une des revendications 1 à 11 selon lequel le mat comprend 80 à 90% de fibre de bois, environ 4 à 9% de résine thermo-formable et environ 4 à 12% d'au moins une autre fibre.
  13. Procédé selon l'une des revendications 1 à 12 selon lequel la chaleur et la pression sont appliquées par l'utilisation de plateaux chauffés.
  14. Procédé selon la revendication 13 selon lequel les plateaux sont chauffés à une température de l'ordre de 150 à 250° C.
  15. Procédé selon l'une des revendications 1 à 14 selon lequel le maximum de la pression exercée est de l'ordre de 20 à 30 kg/cm2.
  16. Procédé selon l'une des revendications 1 à 15 selon lequel la chaleur et la pression sont appliquées pour une durée de 2 à 3,5 minutes comprenant des cycles de repos pour détendre la pression de la vapeur.
  17. Procédé selon l'une des revendications 1 à 16 utilisé pour traiter au moins deux surfaces d'une pièce de bois.
EP94810403A 1993-12-13 1994-07-07 Composite à base de bois Expired - Lifetime EP0657257B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16657593A 1993-12-13 1993-12-13
US166575 1993-12-13

Publications (2)

Publication Number Publication Date
EP0657257A1 EP0657257A1 (fr) 1995-06-14
EP0657257B1 true EP0657257B1 (fr) 1997-12-10

Family

ID=22603888

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94810403A Expired - Lifetime EP0657257B1 (fr) 1993-12-13 1994-07-07 Composite à base de bois

Country Status (4)

Country Link
EP (1) EP0657257B1 (fr)
JP (1) JPH07195315A (fr)
AT (1) ATE160966T1 (fr)
DE (1) DE69407265T2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1022370B1 (fr) * 1999-01-25 2009-06-10 Hexion Specialty Chemicals GmbH Procédé de fabrication de pièces moulées en tissus non-tissés traités en surface
WO2004098876A1 (fr) * 2003-05-09 2004-11-18 Chong Chee Tan Bois de construction renforce et sa production
ITRM20110592A1 (it) * 2011-11-09 2012-02-08 Antonelli Marcello Elemento multistrato flessibile preferibilmente in legno e relativo procedimento di produzione tramite incisione e/o taglio a mezzo laser

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2439016A1 (de) * 1974-08-14 1976-02-26 Krages Thermopal Werk Tischlerplatte
FR2568510B1 (fr) * 1984-08-01 1986-09-05 Garcia Jean Fabrication de panneaux de particules d'agglomeres et ou de fibres, comportant une ame en bois, ou tout autre materiau. bois deroule tranche ou scie
US4612224A (en) * 1985-12-02 1986-09-16 Sheller-Globe Corporation Fiber web for compression molding structural substrates for panels
JPS6420399A (en) * 1987-07-10 1989-01-24 Nichiha Kk Molded fiberboard
JP2963927B2 (ja) * 1990-07-18 1999-10-18 株式会社タケヒロ 自動車用内装基材の製造方法
DE4030774C2 (de) * 1990-09-28 1998-05-20 Dieffenbacher Gmbh Maschf Verfahren zum Herstellen einer Mehrschichtholzplatte und nach diesem Verfahren hergestellte Mehrschichtholzplatte

Also Published As

Publication number Publication date
JPH07195315A (ja) 1995-08-01
ATE160966T1 (de) 1997-12-15
DE69407265D1 (de) 1998-01-22
EP0657257A1 (fr) 1995-06-14
DE69407265T2 (de) 1998-04-23

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