WO1994001259A1 - Method for densifying softwood, and products obtained by such method - Google Patents

Method for densifying softwood, and products obtained by such method Download PDF

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Publication number
WO1994001259A1
WO1994001259A1 PCT/FR1993/000711 FR9300711W WO9401259A1 WO 1994001259 A1 WO1994001259 A1 WO 1994001259A1 FR 9300711 W FR9300711 W FR 9300711W WO 9401259 A1 WO9401259 A1 WO 9401259A1
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WIPO (PCT)
Prior art keywords
wood
impregnation
compression
polymerization
resin
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PCT/FR1993/000711
Other languages
French (fr)
Inventor
Pierre Morlier
Jean-François DUMAIL
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Eurogam
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Publication date
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Priority to AU45730/93A priority Critical patent/AU4573093A/en
Publication of WO1994001259A1 publication Critical patent/WO1994001259A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/001—Heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/02—Processes; Apparatus
    • B27K3/15—Impregnating involving polymerisation including use of polymer-containing impregnating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/06—Softening or hardening of wood
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L97/00—Compositions of lignin-containing materials
    • C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
    • C08L61/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
    • C08L61/28—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with melamine

Definitions

  • the present invention relates to a method of densification of softwoods such as for example maritime pine, as well as the products obtained by this method.
  • softwoods have densities and hardnesses insufficient to be able to be used under conditions where they are subjected to friction and to significant mechanical stresses.
  • the present invention aims to modify softwoods, in particular maritime pine, so as to increase their density and hardness to allow them to be used for example for the production of parquet floors.
  • the subject of the present invention is a process for increasing the hardness of softwoods by obtaining a product of satisfactory appearance, in particular without appreciable modification of the natural appearance of the wood and having good dimensional stability, in particular when moisture is taken up. .
  • the subject of the present invention is a process for the densification of softwoods, in particular maritime pine, characterized in that the wood is impregnated with a melamine-formaldehyde resin under conditions such as the polymerization of this resin remains negligible; that the wood thus impregnated is compressed so as to greatly reduce its volume with a speed and a limiting compression rate lower than those which cause the mechanical deterioration of the wood; and then cause the polymerization then drying of the wood thus compressed by maintaining it under pressure at a temperature of approximately 120 to 150 ° C. for a sufficient duration.
  • the impregnation of wood can be carried out using a melamine-formaldehyde resin such as that sold by the company CECA under the reference R 4293 or by the company ATOCHEM under the reference M502 associated with the hardener. H520, these resins being diluted in water at a rate of approximately 20 to 100% by weight of water per weight of resin.
  • the compression phase of the wood advantageously corresponds to a reduction in the volume of the latter of at least about 40%.
  • the impregnation can be carried out by soaking or impregnation under vacuum according to conventional methods for durations advantageously between 15 minutes and 25 hours.
  • the compression and polymerization / drying phases are carried out successively between the heating plates of the same press.
  • heating plates are used which are kept at a temperature of, for example, between approximately 120 and 150 ° C.
  • the compression phase is immediately carried out by tightening the press plates with a sufficiently high speed so that the desired compression ratio is obtained before the heat released by the press plates causes neither the drying of the wood nor a significant polymerization.
  • melamine-formaldehyde resin contained in the wood is immediately carried out by tightening the press plates with a sufficiently high speed so that the desired compression ratio is obtained before the heat released by the press plates causes neither the drying of the wood nor a significant polymerization.
  • the thickness of the wood being treated can be reduced by approximately 10 to 20 mm per minute without causing mechanical damage and without the heat given off by the heating plates of the press could have caused significant polymerization of the mined-formo1 resin.
  • the pressure exerted by the platens of the press can vary for example from 5 to 10 Mpa.
  • the relative compression ratio that is to say the variation in thickness of the wood with respect to its initial thickness, can for example be between 40 and 60%.
  • the compression of the wood when the compression of the wood has been obtained as indicated above, it is kept under pressure for a time sufficient to ensure the polymerization of the melanin-formaldehyde resin and the drying of the wood, that is to say bring it to a humidity level of around 4%.
  • the wood treated according to the method according to the invention has the advantage of having a high density which can be greater than 1 while its natural density is approximately 0.5.
  • the hardness of the wood treated according to the invention can be up to about 15 Monnin which is a hardness about 3 times higher than that of oak which is generally considered as the reference wood for parquet floors.
  • the present invention also relates to a soft wood treated by the method according to the invention, characterized in that it has a density at least close to 1 and good dimensional stability.
  • Example 1
  • a test specimen is produced in maritime pine having a length of 90 mm, a width of 55 mm and a thickness of 10 mm. Its density of 0.53 and its hardness is 1.7 Monnin.
  • the impregnation is carried out under vacuum for approximately 25 hours.
  • the impregnation rate is 150%, that is to say that the maritime pine specimen absorbed one and a half times its own volume of resin solution.
  • the compression and drying polymerization phases are carried out on the same press, the plates of which are heated to 120 ° C.
  • the impregnated test piece is subjected to compression by lowering the upper plate of the press at a speed of 20 mm per minute until a compression ratio of 52% is obtained, c is a reduction of the thickness of the test piece of 52% compared to its initial thickness.
  • test piece is then kept in the press at constant thickness for approximately 60 minutes the maximum stress is approximately 5 Mpa.
  • the product thus obtained has an unchanged length of 90mm, a width of 57mm and a thickness of 4.7mm. Its density is 1.05 and its hardness is 15 Monnin.
  • EXAMPLE 2 A maritime pine test tube having a length of 90 mm, a width of 55 mm and a thickness of 10 mm is produced. Its density is 0.53 and its hardness 1.7 Monnin.
  • the impregnation under vacuum lasts approximately 2 hours.
  • the impregnation rate is approximately 100%.
  • the trays are at a temperature of 140 ° C.
  • the compression speed is 10 mm / min, up to a compression rate of 50%.
  • the induced stress is around 5 MPa.
  • the product obtained has a length of 90 mm, a width of 57 mm and a thickness of 5 mm. Its density is 1.06 and its hardness 15.5 Monnin.
  • a test specimen is produced in maritime pine having a length of 90 mm, a width of 55 mm and a thickness of 10 mm. Its density is 0.48 and its hardness is 1.5 Monnin. Its impregnation is carried out under vacuum using resin R4293 sold by the company CECA, diluted to 100% in water.
  • Impregnation under vacuum lasts approximately 1 hour.
  • the impregnation rate is approximately 100%.
  • the press plates are at a temperature of 140 ° C.
  • the compression speed is 5mm / min, up to a compression rate of 55%.
  • the induced stress is around 7 MPa.
  • the product obtained has a length of 90 mm, a width of 56 mm and a thickness of 4.5 mm. Its density is 1.08 and its hardness is 16.5 Monnin.
  • the stability is good, of the order of 4% after 48 hours of immersion in water. This swelling is reversible.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Forests & Forestry (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Abstract

The invention relates to a method for densifying softwood, comprising the impregnation of the wood with an organic compound, followed by compression. The organic compound is a melamine-formol resin, impregnation being carried out while the polymerization of such resin is negligible; the wood thus impregnated is compressed so as to considerably reduce its volume, such compression being carried out at speed and limit compression ratio lower than those causing mechanical deterioration of the wood; the polymerization of the melamine-formol resin takes place and the wood is dried by maintaining it under pressure at a temperature of approximately 120 to 150 °C for sufficient time.

Description

- i - i
Procédé de densification des bois tendres et produits obtenus par ce procédé.Densification process for softwoods and products obtained by this process.
La présente invention a pour objet un procédé de densification des bois tendres tels que par exemple le pin maritime, ainsi que les produits obtenus par ce procédé.The present invention relates to a method of densification of softwoods such as for example maritime pine, as well as the products obtained by this method.
On sait que la dureté et par conséquent la résistance à l'usure des bois sont proportionnelles à leur densité.We know that the hardness and therefore the resistance to wear of wood are proportional to their density.
C'est ainsi qu'un certain nombre d'espèces que l'on désigne généralement sous le terme de "bois tendres" présentent des densités et des duretés insuffisantes pour pouvoir être utilisés dans des conditions où ils sont soumis à des frottements et à des contraintes mécaniques importants.Thus, a certain number of species which are generally designated by the term "softwoods" have densities and hardnesses insufficient to be able to be used under conditions where they are subjected to friction and to significant mechanical stresses.
C'est en particulier le cas des parquets dont l'usage est réservé généralement à des bois durs tels que le chêne.This is particularly the case with parquet floors, the use of which is generally reserved for hardwoods such as oak.
La présente invention vise à modifier les bois tendres, notamment le pin maritime, de manière à augmenter leur densité et leur dureté pour leur permettre d'être utilisés par exemple pour la réalisation de parquets. On a déjà imaginé des procédés selon lesquels on soumet le bois à une compression suivie d'un chauffage pour réduire son volume en augmentant sa dureté, mais ces procédés se sont révélés inapplicables dans la pratique en raison du manque de stabilité dimensionnelle des produits obtenus. La présente invention a pour objet un procédé pour augmenter la dureté des bois tendres en obtenant un produit d'aspect satisfaisant, en particulier sans modification sensible de l'aspect naturel du bois et présentant une bonne stabilité dimensionnelle notamment lors de la reprise d'humidité. La présente invention a pour objet un procédé de densification des bois tendres, en particulier du pin maritime, caractérisé par le fait que l'on imprègne le bois à l'aide d'une résine melamine-formol dans des conditions telles que la polymérisation de cette résine demeure négligeable; que l'on comprime le bois ainsi imprégné de manière à réduire fortement son volume avec une vitesse et un taux limite de compression inférieurs à ceux qui provoquent la détérioration mécanique du bois; puis que l'on provoque la polymérisation puis le séchage du bois ainsi comprimé en le maintenant sous pression à une température d'environ 120 à 150°C pendant une durée suffisante.The present invention aims to modify softwoods, in particular maritime pine, so as to increase their density and hardness to allow them to be used for example for the production of parquet floors. We have already devised methods according to which the wood is subjected to compression followed by heating to reduce its volume by increasing its hardness, but these methods have proved inapplicable in practice because of the lack of dimensional stability of the products obtained. The subject of the present invention is a process for increasing the hardness of softwoods by obtaining a product of satisfactory appearance, in particular without appreciable modification of the natural appearance of the wood and having good dimensional stability, in particular when moisture is taken up. . The subject of the present invention is a process for the densification of softwoods, in particular maritime pine, characterized in that the wood is impregnated with a melamine-formaldehyde resin under conditions such as the polymerization of this resin remains negligible; that the wood thus impregnated is compressed so as to greatly reduce its volume with a speed and a limiting compression rate lower than those which cause the mechanical deterioration of the wood; and then cause the polymerization then drying of the wood thus compressed by maintaining it under pressure at a temperature of approximately 120 to 150 ° C. for a sufficient duration.
Conformément à l'invention, l'imprégnation du bois peut être réalisée à l'aide d'une résine melamine-formol telle que celle commercialisée par la Société CECA sous la référence R 4293 ou par la Société ATOCHEM sous la référence M502 associée au durcisseur H520, ces résines étant diluées dans l'eau à raison d'environ 20 à 100 % de poids d'eau par poids de résine. Selon l'invention, la phase de compression du bois correspond avantageusement à une réduction du volume de ce dernier d'au moins environ 40 %.In accordance with the invention, the impregnation of wood can be carried out using a melamine-formaldehyde resin such as that sold by the company CECA under the reference R 4293 or by the company ATOCHEM under the reference M502 associated with the hardener. H520, these resins being diluted in water at a rate of approximately 20 to 100% by weight of water per weight of resin. According to the invention, the compression phase of the wood advantageously corresponds to a reduction in the volume of the latter of at least about 40%.
L'imprégnation peut s'effectuer par trempage ou imprégnation sous vide selon les méthodes conventionnelles pendant des durées avantageusement comprises entre 15 minutes et 25 heures.The impregnation can be carried out by soaking or impregnation under vacuum according to conventional methods for durations advantageously between 15 minutes and 25 hours.
Selon un mode de réalisation préféré de l'invention, les phases de compression et de polymérisation/séchage sont réalisées successivement entre les plateaux chauffants d'une même presse.According to a preferred embodiment of the invention, the compression and polymerization / drying phases are carried out successively between the heating plates of the same press.
On utilise pour cela des plateaux chauffants maintenus à une température comprise par exemple entre environ 120 et 150°C.For this, heating plates are used which are kept at a temperature of, for example, between approximately 120 and 150 ° C.
Là phase de compression est immédiatement réalisée en resserrant les plateaux de la presse avec une vitesse suffisamment grande pour que le taux de compression recherché soit obtenu avant que la chaleur dégagée par les plateaux de la presse ne provoquent ni le séchage du bois ni une polymérisation significative de la résine melamine-formol contenue dans le bois.The compression phase is immediately carried out by tightening the press plates with a sufficiently high speed so that the desired compression ratio is obtained before the heat released by the press plates causes neither the drying of the wood nor a significant polymerization. melamine-formaldehyde resin contained in the wood.
C'est ainsi par exemple qu'avec du pin maritime on peut réduire l'épaisseur du bois en cours de traitement d'environ 10 à 20 mm par minute sans provoquer son endommagement mécanique et sans que la chaleur dégagée par les plateaux chauffants de la presse aient pu provoquer une polymérisation significative de la résine mé1 miné-formo1.For example, with maritime pine, the thickness of the wood being treated can be reduced by approximately 10 to 20 mm per minute without causing mechanical damage and without the heat given off by the heating plates of the press could have caused significant polymerization of the mined-formo1 resin.
Lors de cette phase de compression, la pression exercée par les plateaux de la presse peut varier par exemple de 5 à 10 Mpa. Conformément à l'invention, le taux de compression relatif, c'est-à-dire la variation d'épaisseur du bois par rapport à son épaisseur initiale peut être par exemple compris entre 40 et 60 %. Conformément à l'invention, lorsque la compression du bois a été obtenu comme indiqué précédemment, il est maintenu sous pression pendant un temps suffisant pour assurer la polymérisation de la résine mélanine-formol et le séchage du bois, c'est-à-dire l'amener à un taux d'humidité d'environ 4 %.During this compression phase, the pressure exerted by the platens of the press can vary for example from 5 to 10 Mpa. According to the invention, the relative compression ratio, that is to say the variation in thickness of the wood with respect to its initial thickness, can for example be between 40 and 60%. According to the invention, when the compression of the wood has been obtained as indicated above, it is kept under pressure for a time sufficient to ensure the polymerization of the melanin-formaldehyde resin and the drying of the wood, that is to say bring it to a humidity level of around 4%.
Le bois traité conformément au procédé selon l'invention présente l'avantage de posséder une densité élevée qui peut être supérieure à 1 alors que sa densité naturelle est d'environ 0,5.The wood treated according to the method according to the invention has the advantage of having a high density which can be greater than 1 while its natural density is approximately 0.5.
De même, la dureté du bois traité selon l'invention peut s'élever jusqu'à environ 15 Monnin qui est une dureté environ 3 fois supérieure à celle du chêne qui est généralement considéré comme le bois de référence pour les parquets.Similarly, the hardness of the wood treated according to the invention can be up to about 15 Monnin which is a hardness about 3 times higher than that of oak which is generally considered as the reference wood for parquet floors.
Dans le but de mieux faire comprendre l'invention, on va en décrire maintenant à titre d'illustration plusieurs exemples de mises en oeuvre.In order to better understand the invention, we will now describe by way of illustration several examples of implementation.
La présente invention a également pour objet un bois tendre traité par le procédé selon l'invention, caractérisé par le fait qu'il possède une densité au moins voisine de 1 et une bonne stabilité dimensionnelle. Exemple 1The present invention also relates to a soft wood treated by the method according to the invention, characterized in that it has a density at least close to 1 and good dimensional stability. Example 1
On réalise une éprouvette en pin maritime ayant une longueur de 90 mm, une largeur de 55 mm et une épaisseur de 10 mm. Sa densité de 0,53 et sa dureté est de 1.7 Monnin.A test specimen is produced in maritime pine having a length of 90 mm, a width of 55 mm and a thickness of 10 mm. Its density of 0.53 and its hardness is 1.7 Monnin.
On réalise son imprégnation selon les techniques habituelles à l'aide de la résine vendue par la Société CECA sous la référence R4293 diluée dans un égal volume d'eau.Its impregnation is carried out according to the usual techniques using the resin sold by the company CECA under the reference R4293 diluted in an equal volume of water.
L'imprégnation s'effectue sous vide pendant environ 25 heures. Le taux d'imprégnation est de 150 %, c'est-à-dire que l'éprouvette de pin maritime a absorbé une fois et demi son propre volume de solution de résine.The impregnation is carried out under vacuum for approximately 25 hours. The impregnation rate is 150%, that is to say that the maritime pine specimen absorbed one and a half times its own volume of resin solution.
Les phases de compression et de polymérisation séchage sont réalisées sur une même presse dont les plateaux sont chauffés à 120°C.The compression and drying polymerization phases are carried out on the same press, the plates of which are heated to 120 ° C.
Dès son introduction dans la presse, 1'éprouvette imprégnée est soumise à une compression par abaissement du plateau supérieur de la presse à la vitesse de 20 mm à la minute jusqu'à l'obtention d'un taux de compression de 52 %, c'est-à-dire une réduction de l'épaisseur de l'éprouvette de 52 % par rapport à son épaisseur initiale.As soon as it is introduced into the press, the impregnated test piece is subjected to compression by lowering the upper plate of the press at a speed of 20 mm per minute until a compression ratio of 52% is obtained, c is a reduction of the thickness of the test piece of 52% compared to its initial thickness.
L'éprouvette est ensuite maintenue dans la presse à épaisseur constante pendant environ 60 minutes la contrainte maximale est d'environ 5 Mpa.The test piece is then kept in the press at constant thickness for approximately 60 minutes the maximum stress is approximately 5 Mpa.
Le produit ainsi obtenu présente une longueur inchangée de 90mm, une largeur de 57mm et une épaisseur de 4,7mm. Sa densité est de 1,05 et sa dureté est de 15 Monnin.The product thus obtained has an unchanged length of 90mm, a width of 57mm and a thickness of 4.7mm. Its density is 1.05 and its hardness is 15 Monnin.
Il présente un bel état de surface et ne comporte aucune coloration indésirable. Il possède une bonne stabilité dimensionnelle.It has a good surface condition and does not contain any undesirable coloring. It has good dimensional stability.
Le gonflement du produit est de 5 % après immersion 48 heures dans l'eau. Ce gonflement est réversible lors du séchage. Exemple 2 On réalise une éprouvette en pin maritime ayant une longueur de 90 mm, une largeur de 55 mm et une épaisseur de 10 mm. Sa densité est de 0,53 et sa dureté de 1,7 Monnin.The swelling of the product is 5% after 48 hours immersion in water. This swelling is reversible during drying. EXAMPLE 2 A maritime pine test tube having a length of 90 mm, a width of 55 mm and a thickness of 10 mm is produced. Its density is 0.53 and its hardness 1.7 Monnin.
On réalise son imprégnation sous vide à l'aide de la résine M502, diluée à 20 % en eau, et du durcisseur H520, mélangée à la résine et à l'eau à raison de 0,5 % de durcisseur. Ces produits sont commercialisés par la Société ATOCHEM.Its impregnation is carried out under vacuum using the resin M502, diluted to 20% in water, and the hardener H520, mixed with the resin and with the water at the rate of 0.5% of hardener. These products are marketed by the ATOCHEM Company.
L'imprégnation sous vide dure environ 2 heures.The impregnation under vacuum lasts approximately 2 hours.
Le taux d'imprégnation est de 100 % environ. Les plateaux sont à une température de 140°C. La vitesse de compression est de lOmm/mn, jusqu'à un taux de compression de 50 %. La contrainte induite est d'environ 5 Mpa.The impregnation rate is approximately 100%. The trays are at a temperature of 140 ° C. The compression speed is 10 mm / min, up to a compression rate of 50%. The induced stress is around 5 MPa.
Le produit obtenu a une longueur de 90 mm, une largeur de 57 mm et une épaisseur de 5 mm. Sa densité est de 1,06 et sa dureté de 15,5 Monnin.The product obtained has a length of 90 mm, a width of 57 mm and a thickness of 5 mm. Its density is 1.06 and its hardness 15.5 Monnin.
La stabilité est bonne, de l'ordre de 4 % après 48 heures d'immersion dans l'eau et de 8,7 % après 96 heures. Ce gonflement est réversible par séchage. Exemple 3The stability is good, of the order of 4% after 48 hours of immersion in water and 8.7% after 96 hours. This swelling is reversible on drying. Example 3
On réalise une éprouvette en pin maritime ayant une longueur de 90 mm, une largeur de 55 mm et une épaisseur de 10 mm. Sa densité est de 0,48 et sa dureté de 1,5 Monnin. On réalise son imprégnation sous vide à l'aide de la résine R4293 commercialisée par la Société CECA, diluée à 100 % en eau.A test specimen is produced in maritime pine having a length of 90 mm, a width of 55 mm and a thickness of 10 mm. Its density is 0.48 and its hardness is 1.5 Monnin. Its impregnation is carried out under vacuum using resin R4293 sold by the company CECA, diluted to 100% in water.
L'imprégnation sous vide dure environ 1 heure.Impregnation under vacuum lasts approximately 1 hour.
Le taux d'imprégnation est de 100% environ. Les plateaux de la presse sont à une température de 140°C. La vitesse de compression est de 5mm/mn, jusqu'à un taux de compression de 55 %. La contrainte induite est d'environ 7 Mpa.The impregnation rate is approximately 100%. The press plates are at a temperature of 140 ° C. The compression speed is 5mm / min, up to a compression rate of 55%. The induced stress is around 7 MPa.
Le produit obtenu a une longueur de 90 mm, une largeur de 56 mm et une épaisseur de 4,5 mm. Sa densité est de 1,08 et sa dureté de 16,5 Monnin.The product obtained has a length of 90 mm, a width of 56 mm and a thickness of 4.5 mm. Its density is 1.08 and its hardness is 16.5 Monnin.
La stabilité est bonne, de l'ordre de 4 % après 48 heures d'immersion dans l'eau. Ce gonflement est réversible.The stability is good, of the order of 4% after 48 hours of immersion in water. This swelling is reversible.
Des résultats similaires sont obtenus avec d'autres essences de bois tendres tels que le peuplier, le frêne ou le hêtre. Similar results are obtained with other soft wood species such as poplar, ash or beech.

Claims

REVENDICATION 1 - Procédé de densification des bois tendres, comportant une imprégnation du bois à l'aide d'un composé organique suivie d'une compression, caractérisé par le fait que le composé organique est une résine melamine-formol, l'imprégnation s'effectuant sans que la polymérisation de cette résine cesse d'être négligeable ; que l'on comprime le bois ainsi imprégné de manière ; à réduire fortement son volume à une vitesse et un taux limite de compression inférieurs à ceux qui provoquent la détérioration mécanique du bois ; et que l'on provoque la polymérisation de la résine melamine-formol puis le séchage du bois en le maintenant sous pression à une température d'environ 120 à 150CC pendant une durée suffisante.CLAIM 1 - Process for densification of softwoods, comprising an impregnation of the wood using an organic compound followed by compression, characterized in that the organic compound is a melamine-formaldehyde resin, the impregnation is performing without the polymerization of this resin ceasing to be negligible; that the wood thus impregnated is so compressed; to greatly reduce its volume at a speed and a limiting compression rate lower than those which cause mechanical deterioration of the wood; and that it causes the polymerization of the melamine-formaldehyde resin and then drying the timber by maintaining the pressure at a temperature of about 120 to 150 C C for a sufficient time.
2 - Procédé selon la revendication 1, caractérisé par le fait que le bois traité est le pin maritime.2 - Method according to claim 1, characterized in that the treated wood is maritime pine.
3 - Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait qu'en vue de l'imprégnation du bois, les résines melamine-formol sont diluées dans l'eau à raison d'environ 20 à 100 Z de poids d'eau par poids de résine.3 - Method according to any one of the preceding claims, characterized in that for the impregnation of the wood, the melamine-formaldehyde resins are diluted in water at a rate of about 20 to 100% by weight d by weight of resin.
4 - Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait que la phase de compression du bois correspond à une réduction de volume d'au moins d'environ 40 7..4 - Method according to any one of the preceding claims, characterized in that the compression phase of the wood corresponds to a reduction in volume of at least about 40 7 ..
5 - Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait que l'imprégnation s'effectue par trempage ou par imprégnation sous vide pendant une durée comprise entre environ 15 minutes et 25 heures. 6 - Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait que les phases de compression et de polymérisation/séchage sont effectuées successivement entre les plateaux chauffants d'une même presse.5 - Method according to any one of the preceding claims, characterized in that the impregnation is carried out by soaking or by vacuum impregnation for a period of between about 15 minutes and 25 hours. 6 - Process according to any one of the preceding claims, characterized in that the compression and polymerization / drying phases are carried out successively between the heating plates of the same press.
7 - Procédé selon l'une quelconque des revendications précédentes, caractérisé par le fait que les plateaux chauffants de la presse qui assure la polymérisation de la résine sont maintenus à une température comprise entre environ 120 et 150°C.7 - Method according to any one of the preceding claims, characterized in that the heating plates of the press which ensures the polymerization of the resin are maintained at a temperature between about 120 and 150 ° C.
8 - Procédé selon la revendication 6, caractérisé par le fait que la phase de compression est réalisée en resserrant les plateaux de la presse avec une vitesse suffisamment grande pour que le taux de compression recherché soit obtenu avant que n'intervienne une polymérisation significative de la résine melamine-formol contenue dans le bois. 9 - Procédé selon la revendication 8 , caractérisé par le fait x . que l'on réduit l'épaisseur du bois à une vitesse d'environ 10 à 20 mm par minute.8 - Process according to claim 6, characterized in that the compression phase is carried out by tightening the platens of the press with a sufficiently high speed so that the desired compression ratio is obtained before a significant polymerization of the melamine-formaldehyde resin contained in the wood. 9 - Method according to claim 8, characterized by the fact x. that the thickness of the wood is reduced at a speed of about 10 to 20 mm per minute.
10 - Bois tendre traité par le procédé selon l'invention, caractérisé par le fait qu'il possède une densité au moins voisine de 1 et une bonne stabilité dimensionnelle. 10 - Softwood treated by the method according to the invention, characterized in that it has a density at least close to 1 and good dimensional stability.
PCT/FR1993/000711 1992-07-10 1993-07-09 Method for densifying softwood, and products obtained by such method WO1994001259A1 (en)

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AU45730/93A AU4573093A (en) 1992-07-10 1993-07-09 Method for densifying softwood, and products obtained by such method

Applications Claiming Priority (2)

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FR9208600A FR2693398B1 (en) 1992-07-10 1992-07-10 Densification process for softwoods and products obtained by this process.
FR92/08600 1992-07-10

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FR2722724B1 (en) * 1994-07-22 1996-10-04 Bois Densifies WOODEN DENSIFICATION PROCESS AND PRODUCTS OBTAINED THEREBY
FR2738495B1 (en) * 1995-09-12 1997-12-05 Salomon Sa PROCESS FOR THE MANUFACTURE OF A SKI OR SKI COMPONENT COMPRISING A THERMOCOMPRESSION STAGE OF A WOODEN CORE BLANK
CN111308057B (en) * 2019-11-04 2022-02-15 内蒙古农业大学 Method for determining wood section processing conditions for veneer cutting and evaluating processing effect

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US11498240B2 (en) 2017-12-29 2022-11-15 Ahf, Llc Densified wood including process for preparation
US11931917B2 (en) 2017-12-29 2024-03-19 Ahf, Llc Densified wood including process for preparation

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AU4573093A (en) 1994-01-31
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