WO2003041926A1 - Procede de pre-traitement du bois - Google Patents

Procede de pre-traitement du bois Download PDF

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Publication number
WO2003041926A1
WO2003041926A1 PCT/FI2002/000890 FI0200890W WO03041926A1 WO 2003041926 A1 WO2003041926 A1 WO 2003041926A1 FI 0200890 W FI0200890 W FI 0200890W WO 03041926 A1 WO03041926 A1 WO 03041926A1
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WO
WIPO (PCT)
Prior art keywords
wood
accordance
temperature
liquid
bathed
Prior art date
Application number
PCT/FI2002/000890
Other languages
English (en)
Inventor
Veikko MÖTTÖNEN
Original Assignee
KÄRKI, Timo
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 KÄRKI, Timo filed Critical KÄRKI, Timo
Publication of WO2003041926A1 publication Critical patent/WO2003041926A1/fr

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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
    • B27K3/0207—Pretreatment of wood before impregnation
    • 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
    • B27K5/04—Combined bleaching or impregnating and drying of wood

Definitions

  • the present invention relates to a method for pretreating timber, in which method sawn wood is immersed to liquid and the wood is bathed at suitable temperature and under suitable pressure in the liquid before drying.
  • Discolorations in wood Usually discolorations are the greater the higher temperature in mechanical drying is used. Discolorations usually appear in the inner part of wood as darkenings or places turned into red. Usually they may not be noticed on the surface or on the outer layer of dried wood as the surface stays lighter as it dries quicker than the inner part under (from the discoloration point of view) the critical humidity before the temperature of the drying section is raised to separate the firm bonded water from wood. Discolorations created in the inner part of wood prevent the processing, for example to glue laminated board or other decorative products while they appear as spots and stripes on the surface of products.
  • Compounds in polymerization may react also in the absence of oxygen if the temperature of wood is high enough and acidity low enough. If there is no oxygen available while polymerization takes place, the reaction products are colourless or only slightly coloured as less chromofors, side- chains of polymer causing colour, are created.
  • Discolorations during drying processes are tried to be avoided by slowing down the drying in the early state of the drying process to the saturation point of grain (PSK). This has required the drying temperature to be under 55°C until the average humidity of wood has decreased to be under 20%. Disadvantage in this kind of method is, naturally, the lengthening of drying time. Due to careful drying the drying process of birch wood for example, takes 2 - 3 weeks by using the method of warm air-drying. Another way to decrease discoloration is drying outside before mechanical drying until humidity of wood has decreased to be under 30%. This takes usually several months. Furthermore, results are unreliable as the drying depends on the weather. While considering of effective production the earlier mentioned hindering methods of discoloration cause for instance great costs as much drying capacity is needed and stocks are needed to be large.
  • the object of the invention is to provide a method for preliminary treatment of wood, by using of which the earlier mentioned disadvantages are eliminated. Especially, the object of the invention is to provide a method for preliminary treatment of wood, by using of which discolorations created while using mechanical drying of wood may considerable be eliminated. Furthermore, the object of the invention is to provide a method for preliminary treatment of wood, which is clearly quicker and more effective than the earlier known methods for preventing of discolorations created while drying wood mechanically, and by using of which deformations and crackings due to those taking place in wood dried mechanically, are reduced as well as homogenous drying of various parts of wood is achieved.
  • Characteristic to the method in accordance with the invention is the fact, that wood is bathed at temperature 40-100°C and under pressure 0,5-10 bar for 6-72 hour, after which chemical reactions causing discolorations of wood have taken place, at least partially, and that after bathing wood is dried mechanically. Chemical reactions do not cause disadvantageous discolorations if they take place in wood in oxygen-free substance. While using preliminary treatment at this temperature, under this pressure and for this duration of bathing, it is possible to have so many chemical reactions causing discoloration before mechanical drying, that clearly less disadvantageous discolorations takes place in mechanical drying than earlier, such avoiding problems caused by those later. This is why chemical reactions causing discoloration occur less when drying wood treated with method than when using wood without such treatment.
  • this kind of method decreases disadvantageous deformations occurring during drying process, as bathing evens the differences in humidity in various parts of fresh wood.
  • wood from broad-leaved tree species is preliminary treated by the method. Tests indicate that it is possible to minimize discoloration more with broad-leaved tree species while using this kind of preliminary treatment than with coniferous tree species.
  • broad-leaved tree species are broadly used in furniture industry, where discoloration of wood causes great costs, so that eliminating discoloration problems with broad-leaved tree species is very profitable.
  • water serves as substance.
  • Water is an economical substance due to acquisition and operation costs. While bathing wood in water the rising temperature, organic acids in wood and pressure rising lead to rising acidity. Due to rising acidity reactions having influence on discoloration increase they take place in absence of oxygen. Furthermore, preliminary treatment in water decreases disadvantageous deformations during drying process, because bathing in water equalizes differences in humidity in various parts of fresh wood. Furthermore, while using water as substance, the construction of equipment for preliminary treatment is able to be constructed simple as well as economical by manufacturing and operating costs.
  • substance liquid is used, by using which it is possible to regulate the acidity of treated wood suitable in order the chemical reactions connected with coloration to happen.
  • This kind of liquid can be easily available, advantageous and non-toxic acidity controlling substance, for example, water solution of weak acid or salt solution.
  • this kind of substance possesses the same earlier mentioned properties in equalizing differences in humidity of wood as water does.
  • preliminary treatment equipment which includes a basin-like treatment space where wood may be placed by means of a separate piling rack.
  • the basin-like space includes a basin, which may be filled with liquid substance.
  • Substance may be water or some other liquid solution depending on wood to be treated.
  • the basin includes also a cover to be closed with a hatch, with which the open upper part of the basin may be closed after the piling rack has been immersed to the basin.
  • the basin includes a heater, which is in this case, a spiral-like electric resistor placed, for example, on the bottom or on a wall of the basin and includes also temperature sensor for measuring the temperature of the substance. The purpose of the heater is to heat the substance and to keep it at the wanted temperature during bathing.
  • control unit For controlling the equipment there is a control unit connected to the equipment, which consists controlling and regulating appliances for controling the preliminary treatment process according to earlier given programme.
  • Controlling unit may also be build up, for example, of a computer and controlling electronics connected to it, which automatically control the equipment according to given information from the computer and from the measuring data from the temperature sensor in the basin.
  • the equipment has a suitable chamber piling rack separate from the chambers, on which the wood is piled in such a way, that there will be empty space horizontally and vertically between the pieces of wood for substance penetrate round the wood pieces as required. This as even and efficient as possible absorption of substance to wood.
  • the piling rack is constructed such a way, that the whole space of the basin may be utilized as exactly as possible.
  • the piling rack used in preliminary treatment may advantageously be used in drying machine of wood. After preliminary treatment the piling rack is moved straight from the preliminary treatment space to drying chamber of a drying machine. This is how transporting of separate pieces of wood from one place to another is avoided.
  • FIG 1 there are schemes in which discolorations of birch saw material treated with the earlier explained method and discolorations of birch saw material without corresponding treatment used as comparison material are compared.
  • the schemes present colour parametres of lightness (L*) and redness (a*) measured with a spectrophotometer from the inner part of 38 mm x 100 mm birch saw material, quick-dried at temperature of 120°C in preliminary treatment periods of various lengths.
  • Initial situation is the colour of saw material in mechanical dried wood without preliminary treatment. Lightness increases and redness decreases while preliminary treatment time gets longer.
  • the method in accordance with the invention may be realized in many various ways differing from above explained application example.
  • the temperature of the liquid substance used in the treatment depends on the tree species of the treated wood, because the temperature required for chemical reactions for discoloration to take place varies on various tree species. Furthermore, cross-section parametres of wood, humidity of wood as well as other qualitative facts have influence on temperature. Best results may be achieved when the temperature of the liquid used as substance is 40-100°C.
  • treatment time varies. Treatment time depends, mostly, on cross-section parametres, but also on tree species and other facts, such as humidity of wood before starting the treatment. The most favourable treatment time would be 6-72 hours. In application examples explained above the treatment space was an open bath basin under normal pressure, but the treatment space may also be a closed space.
  • bathing may also be realized by treating an amount of wood in a treatment chamber with 0,5-10 bar pressure.
  • pressure increases the absorption of substance gets more effective and quicker, which shortens the treatment time and improves results of the treatment.
  • the use of pressure increases the acidity of the used substance. This kind of pressure is easy to achieve while using the treatment equipment of wood in accordance with the invention.
  • bathing may be carried out even before sawing when wood is in the form of logs, when wood may be dried straight after sawing.
  • the equipment used in the method in accordance with the invention may also be realized in many different ways differing from application examples explained above.
  • the treatment space being a part of the equipment may be an open basin, basin to be closed with a cover or, for example, some suitable chamber-type space, which may be filled with liquid substance. Construction and size of the treatment space depends on the amount of wood to be treated at one time, but also on the way wood is transported to the treatment space for treatment. If the treatment is carried out under pressure the space has been built tight and to hold the used pressure.
  • the heater for heating substance may also be other that an electrical heater. It may be, for instance a heating tube spiral or some other radiator-type heater using separate substance, with which the substance in the chamber is able to be heated and kept in desired temperature in functional way.
  • the piling rack may be organized, for example, to be moved on rails or on wheels in and out from the chamber.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Drying Of Solid Materials (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Abstract

La présente invention concerne un procédé qui permet de pré-traiter le bois, selon lequel on immerge le bois dans un liquide et on le laisse tremper à une température appropriée avant de le sécher. Le procédé de l'invention est caractérisé en ce que l'on immerge le bois dans un liquide à une température de 40 à 100 °C et sous une pression de 0,5 à 10 bar pendant une durée comprise entre 6 et 72 heures, après quoi les réactions chimiques entraînant la décoloration du bois se sont au moins partiellement produites, et on procède ensuite au séchage mécanique du bois trempé.
PCT/FI2002/000890 2001-11-13 2002-11-11 Procede de pre-traitement du bois WO2003041926A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20012197A FI113955B (fi) 2001-11-13 2001-11-13 Menetelmä sahatun puutavaran esikäsittelemiseksi
FI20012197 2001-11-13

Publications (1)

Publication Number Publication Date
WO2003041926A1 true WO2003041926A1 (fr) 2003-05-22

Family

ID=8562241

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2002/000890 WO2003041926A1 (fr) 2001-11-13 2002-11-11 Procede de pre-traitement du bois

Country Status (2)

Country Link
FI (1) FI113955B (fr)
WO (1) WO2003041926A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012105501A1 (de) * 2012-06-25 2014-01-02 Rolf Goldschmidt Verwitterte Holzoberfläche

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE341375C (fr) *
DE338809C (de) * 1920-07-01 1921-07-01 A Faber Dr Verfahren zur vollkommen gleichmaessigen Durchfaerbung und Impraegnierung von Holz und aehnlichen Stoffen
DE349812C (de) * 1918-04-09 1922-03-09 Prosper Eugene Simon Verfahren zum Entfaerben von Furnieren aus exotischen Hoelzern
US2726169A (en) * 1953-08-12 1955-12-06 Monie S Hudson Process of stabilizing wood by treating it with halogenated ethers
GB1283683A (en) * 1970-01-23 1972-08-02 Combinatul Pentru Industrialza Process and installation for treating oaken veneer
DE3229826A1 (de) * 1982-08-11 1984-02-16 Hans-Jürgen 2000 Hamburg Schulz Behandlungsverfahren fuer frisch gefaelltes naturholz zur qualitaetsverbesserung bzw. beschleunigten alterung und verwendung desselben
FR2544222A1 (fr) * 1983-04-13 1984-10-19 Fanjat De Saint Font Andre Procede de fragmentation ou de defibrement de materiaux poreux permeables
NL8403097A (nl) * 1984-10-11 1986-05-01 Svedex B V Werkwijze voor het voorbehandelen van onbehandeld hout.
JPS61270106A (ja) * 1985-05-27 1986-11-29 松下電工株式会社 改質木材の製法
DE3826798A1 (de) * 1987-08-08 1989-02-16 Wolman Gmbh Dr Verfahren zur impraegnierung von fichtenholz
JPH1044107A (ja) * 1996-08-06 1998-02-17 Rogu Hoomuzu Izumi:Kk 木材内部の樹液等の流去方法とこの前処理を前提とした防腐剤の浸透処理方法
JP3128559B2 (ja) * 1991-11-15 2001-01-29 木材性能向上技術研究組合 木質材の前処理方法

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE341375C (fr) *
DE349812C (de) * 1918-04-09 1922-03-09 Prosper Eugene Simon Verfahren zum Entfaerben von Furnieren aus exotischen Hoelzern
DE338809C (de) * 1920-07-01 1921-07-01 A Faber Dr Verfahren zur vollkommen gleichmaessigen Durchfaerbung und Impraegnierung von Holz und aehnlichen Stoffen
US2726169A (en) * 1953-08-12 1955-12-06 Monie S Hudson Process of stabilizing wood by treating it with halogenated ethers
GB1283683A (en) * 1970-01-23 1972-08-02 Combinatul Pentru Industrialza Process and installation for treating oaken veneer
DE3229826A1 (de) * 1982-08-11 1984-02-16 Hans-Jürgen 2000 Hamburg Schulz Behandlungsverfahren fuer frisch gefaelltes naturholz zur qualitaetsverbesserung bzw. beschleunigten alterung und verwendung desselben
FR2544222A1 (fr) * 1983-04-13 1984-10-19 Fanjat De Saint Font Andre Procede de fragmentation ou de defibrement de materiaux poreux permeables
NL8403097A (nl) * 1984-10-11 1986-05-01 Svedex B V Werkwijze voor het voorbehandelen van onbehandeld hout.
JPS61270106A (ja) * 1985-05-27 1986-11-29 松下電工株式会社 改質木材の製法
DE3826798A1 (de) * 1987-08-08 1989-02-16 Wolman Gmbh Dr Verfahren zur impraegnierung von fichtenholz
JP3128559B2 (ja) * 1991-11-15 2001-01-29 木材性能向上技術研究組合 木質材の前処理方法
JPH1044107A (ja) * 1996-08-06 1998-02-17 Rogu Hoomuzu Izumi:Kk 木材内部の樹液等の流去方法とこの前処理を前提とした防腐剤の浸透処理方法

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 199702, Derwent World Patents Index; Class F09, AN 1987-011627, XP002962533 *
DATABASE WPI Week 199817, Derwent World Patents Index; Class C07, AN 1998-187923, XP002962534 *
DATABASE WPI Week 200113, Derwent World Patents Index; Class A32, AN 1993-252135, XP002962532 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012105501A1 (de) * 2012-06-25 2014-01-02 Rolf Goldschmidt Verwitterte Holzoberfläche

Also Published As

Publication number Publication date
FI20012197A0 (fi) 2001-11-13
FI113955B (fi) 2004-07-15
FI20012197A (fi) 2003-05-14

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