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
  • B27N3/08—Moulding or pressing
• • 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
  • B27N1/00—Pretreatment of moulding material
  • B27N1/003—Pretreatment of moulding material for reducing formaldehyde gas emission
• • 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
  • B27N1/00—Pretreatment of moulding material
• • 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
  • B27N1/00—Pretreatment of moulding material
  • B27N1/006—Pretreatment of moulding material for increasing resistance to swelling by humidity
• • 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

Definitions

• the invention relates to a method for the production of a wood material article with a low emission of chemical compounds as well as a wood material article, which can be obtained by this method.
• Wood material articles as for example, chip boards or fibre boards, are produced of wood chips of fibre materials in combination with glue.
• the glue is applied during the manufacturing of the wood material article onto the hackled wood (chips) or the fibre material and after that the resulting, still moist wood material articles are pressed with high temperatures (hot pressing), whereby the glue is cured respectively hardened.
• formaldehyde containing resins are used in such glues as curing agents and/or binding agents.
• Wood material boards are often used inside of closed rooms. Therefore it is important, that the chipboards do not emit disturbing (like, for example, components with a strong smell) or even harmful components.
• the emitted components can derive from the wood itself or also from the applied glue.
• the resulting articles When using formaldehyde containing resins for the manufacturing of wood material articles, the resulting articles emit amounts of formaldehyde, whereby the amount is limited due to legal regulations and voluntarily restrictions of the industry to extremely low thresholds.
• This object is solved by a method for the production of a wood material article comprising wood chips or wood fibres which are glued together, wherein the wood is treated with bisulphite before the gluing process.
• improved wood material articles can be produced, which in particular show only low or no undesired emissions of (volatile) chemical compounds which originate from the wood itself. Further, the wood chips or wood fibres treated with bisulphite show an improved reaction with the glue.
• wood of broad leaved trees or needle leaved trees are treated either separately or in a mixture.
• the woods are barked and hackled.
• Hackle chips or wood chips can be added to the hackled wood.
• this mixture is screened and separated, whereby undesired articles like for example sand, splinters, stones or metals are removed.
• the mixture is washed, whereby again undesired materials like for example sand or stones are removed.
• the hackled wood is heated and dehydrated. This is done preferably by pressing.
• the hackled and treated wood is then treated at a pressure of 0.8-12 bar in saturated water steam atmosphere.
• an aquarious solution of bisulphate salt is introduced into the steam atmosphere.
• the bisulphate salts may for example be alkali and/or ammonium salts. Preferably sodium salts and/or ammonium bisulphate salts are used. Ammonia salt is particularly preferred.
• the amount of bisulphate salt is in the range of 3 to 30 kg, preferably between 3 and 12 kg per cubic meter of produced board.
• the duration of the treatment is at least 1.5 minutes and preferably between 3 and 8 minutes. In this case large amounts of bisulphate necessitate longer treatment duration to complete the reaction, to enable the bisulphate to permeate into the fibres and to secure a stable impregnation.
• the wood is treated with bisulphate before the production of the wood chips or wood fibres, for example in the cooker, to simplify the implementation of the method.
• a subsequent impregnation of the wood fibres with paraphine does therefore not negatively influence the effect of the method according to the invention.
• the wood chips or wood fibres are treated with bisulphate, for example in a refiner.
• the method can be achieved in a particularly efficient manner.
• the treatment of the hackled wood with the bisulphate is important to bind the volatile substances in the hackled wood and to restrain the regeneration of volatile substances.
• the bisulphate for example the bisulphate-adducts of aldehydes, methylketone or alpha-ketoester may be formed.
• the bisulphate may evolve its bleaching effect and it may react with the pigments present in the wood, so that particularly bright wood material articles can be achieved.
• the brightness of a board is an important quality criterion.
• the glue which is used for the gluing of the wood chips or wood fibres, is preferably an aminoplast resin. It is particularly preferred, that a formaldehyde containing resin is used. This is preferably chosen from the group consisting of urea formaldehyde resin, melanin-formaldehyde resin, urea melanin-formaldehyde resin and melamine urea-phenol-formaldehyde resin. Suitable resins are commercially available as solutions or as powder and the production and application of suitable resins is also described in the prior art. For the method according to the invention, in particular urea-formaldehyde resins and urea-melamine-formaldehyde resins are preferred, which are applied in common amounts.
• resins which are low of formaldehyde which show a low molar relation of formaldehyde to urea.
• the molar relation of formaldehyde to urea is advantageously between 0.8:1 to 1.05:1.
• the glue may comprise in addition to the aminoplast resin further additives as for example curing agents to accelerate the curing or hardening, hydrophobic agents, inert salts, pH-conditioners, stabilizers, fungicides or biocides.
• the gluing is achieved preferably by pressing the finally hackled wood, which is provided with the glue, at temperatures of 120° to 250° Celsius. Under these conditions, the aminoplast resin cures relatively fast and one achieves wood material articles with positive mechanical properties, which are for the most part insensitive against moisture.
• Two fibre boards S1 and V1 were produced with the above described method by using a formaldehyde-urea resin, having a molar ratio of formaldehyde to urea of 1:1.08, with the only distinguishing feature, that for the manufacturing of the fibre board V1 the hackled wood was not treated with bisulphate before the impregnation process.
• the treatment of the hackled wood with bisulphate was done at a pressure of 8.5 bar with an amount of bisulphate of 3 kg per m 3 of hackled wood and for a duration of 3.5 minutes. After the pre-treatment of the wood, the wetting with a none-impregnation agent and after that the pressing was done.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Related Parent Applications (1)

Related Child Applications (1)

Publications (1)

Family

ID=35134611

Family Applications (5)

Family Applications After (4)

Country Status (10)

Cited By (2)

Families Citing this family (7)

Citations (9)

Family Cites Families (8)

• 2005
  • 2005-07-27 PL PL05763977T patent/PL1907178T3/pl unknown
  • 2005-07-27 CA CA002616336A patent/CA2616336A1/en not_active Abandoned
  • 2005-07-27 US US11/989,415 patent/US20090145564A1/en not_active Abandoned
  • 2005-07-27 LT LTEP05763977.5T patent/LT1907178T/lt unknown
  • 2005-07-27 WO PCT/EP2005/053674 patent/WO2007012350A1/de active Application Filing
  • 2005-07-27 ES ES05763977.5T patent/ES2599909T3/es active Active
  • 2005-07-27 PT PT57639775T patent/PT1907178T/pt unknown
  • 2005-07-27 EP EP05763977.5A patent/EP1907178B1/de active Active
  • 2005-07-27 AU AU2005334999A patent/AU2005334999A1/en not_active Abandoned
  • 2005-07-27 CN CN2005800516974A patent/CN101351313B/zh active Active
• 2011
  • 2011-12-06 US US13/312,469 patent/US20120077908A1/en not_active Abandoned
• 2016
  • 2016-07-05 US US15/202,097 patent/US20160311130A1/en not_active Abandoned
• 2017
  • 2017-04-06 US US15/480,964 patent/US20170210028A1/en not_active Abandoned
• 2018
  • 2018-04-25 US US15/962,793 patent/US20180243939A1/en not_active Abandoned

Patent Citations (9)

Also Published As

Similar Documents

Legal Events