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

Definitions

• the invention relates to a cork composite panel with a glued Lignocellulose particles such as wood chips or fibers pressed carrier layer and at least one with the Carrier layer connected top layer made of cork. Furthermore concerns the invention a method for producing a multilayer Composite chipboard or fibreboard, in which at least one Layer consists of cork particles.
• Cork boards are needed for many purposes, e.g. as insulation panels in refrigerators. It is also known to have floors, Walls and ceilings for noise or impact sound insulation or to be covered with cork boards for thermal insulation or to dress up from a base layer of wood or Fiber material and a thin top layer of cork. For Manufacture of such composite panels, it is common to have a prefabricated one Cork board on the surface in a separate process glue on the already finished carrier board. The Production of composite panels with wood chips in the middle layer and cork particles in the top layer in one step As far as is known, the pressing process is not state of the art.
• a binder for the production of chipboard can use acid curing modified and unmodified urea formaldehyde resins (UF resins), phenol formaldehyde resins (PF resins) and adhesives based on diisocyanates (PMDI) become.
• Another method can also use tannin formaldehyde resins (TF resins) as binders for manufacturing of wood chipboard are used (EP-PS 0 788 866).
• TF resins tannin formaldehyde resins
• binders such as starch and proteins have so far not achieved any industrial importance as binders, in principle, however, they can work alone or in combination can be used with other binders.
• Chipboard and fiberboard can be made in one or more layers become. In the different layers there can be different Binders are used. So are chipboards with aminoplast resins known in the outer layers while for the middle layer a binder based on diisocyanate (PMDI) is used (EP-PS-0 012 169). To reduce formaldehyde release is the addition of formaldehyde-active substances in the layers glued with PMDI recommended (EP-PS 0 012 169).
• PMDI diisocyanate
• cork boards with urea formaldehyde resins and made with melamine modified urea formaldehyde resins. The production of cork boards can be done on conventional press systems chipboard production.
• cork has an inherent tendency to spring back, which is why high grinding losses after pressing by grinding must be expected.
• the relatively high resilience is due to the fact that the bulk density of the cork is relatively low and reaches values of approx. 0.1 g / cm 3 , so the cork has high bulk densities of 0.6-0.7 g / cm after compression 3 , as is common with chipboard, and a high tendency to spring back.
• Cork particles for the production of cork boards can either be obtained from the first peeling of the cork oak after about 25 years of growth or from residues from bottle cork production.
• the cork oak trees reach around 25 years of age, they are peeled for the first time, after which the trees are peeled once every 9 to 10 years.
• the cork oaks can reach an age of 150 to 160 years.
• the first peeling "virgin cork” is relatively hard and unsuitable for the production of bottle cork.
• Bottle cork is only extracted from the bark of the oak cork trees after the second peeling. Both the so-called "virgin cork” and the remains from bottle cork production can be used for the production of cork boards.
• the cork particles are crushed and dried in conventional drum dryers to a moisture content of 1% or less. After drying, the granules or particles are glued with the binder, sprinkled into cork mats and then pressed hot.
• the bulk density of the cork boards produced is usually 0.5-0.55 g / cm 3 .
• Cork boards for the floor area are usually made with a provided moisture-resistant glue. This can be alkaline curing phenol formaldehyde resins are used. This however, contain free phenols that can be released. Cork boards for the wall area are usually made with urea formaldehyde resins manufactured. Because of the ones already mentioned Open structure of the cork boards can inadmissible this formaldehyde Deliver quantities. Cork boards for the floor area need have a certain hardness according to ISO 3810. These requirements are difficult to reach.
• Cork plates that come into direct contact with food can be provided with protein glue.
• the invention is based on the object Cork composite panel to create the easier and with less Process and cost expenditure can be produced than before and good has physical properties.
• the cork composite panel described here is therefore not as before in several successive steps by gluing separately manufactured prefabricated chipboard and cork boards, but as a whole in one and the same operation.
• the simplification due to the formation of the composite panel in one Process step means a substantial reduction in manufacturing costs.
• the composite panel has the advantage of particularly good and close connection between those through the joint pressing formed layers. The process of There is no need to sand chipboard after it has been manufactured the one-step operation when the backing layer consists of the two Sides are provided with cork boards in the top layer.
• a cork cover layer made of glued cork particles can build up one or both sides of the carrier layer.
• Production can take place in the manner known in principle in the case of multilayer chipboard. Accordingly, conventional wood chips can be glued for a carrier or middle layer, while cork particles can be glued for the or each top layer. In a scattering station, the cork particles can be scattered into the outer zones of the composite panels by top layer machines, while the middle layer is formed from scattered wood chips. The sprinkled chip / cork cake is then pressed in a press and the glue connecting the particles is cured.
• the pressing pressure can be, for example, 15 to 35 kg / cm 2 , the pressing temperature, for example, 150 to 250 ° C.
• the following are suitable for gluing the cork and middle layers: Isocyanate, phenolic resin, melamine urea phenolic resin, urea resin and PVAC glue, but especially natural glue such as preferably tannin.
• Isocyanate phenolic resin
• melamine urea phenolic resin melamine urea resin
• PVAC glue but especially natural glue such as preferably tannin.
• natural glue such as preferably tannin.
• Glue can expediently be used for the different layers Glue can be used.
• the thickness and density of the composite panels can vary depending on the Purpose to be varied. For insulation purposes, the Usually a low density is aimed for. This can be about increasing of the share of the cork top layers. So it can Cork layer between 15% and 75% of the total board weight turn off.
• the total panel thickness can be used for the insulation purposes mentioned at the beginning for example, 4 mm to 70 mm, while the top layer thickness depending on the total panel thickness and requirement 1 to 10 mm can be.
• the plates For comparison, 12 mm thick cork boards with a melamine formaldehyde resin manufactured, the plates contained no wood chips in the middle class, but both in the cover as well cork shot in the middle class. The binder expenditure was included 12% in both the top and middle class. The so produced plates had a formaldehyde emission in the Test chamber of 0.12 ppm and a springback according to ISO 3810 from 3% on.

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• 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)

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• 2000
  • 2000-04-20 EP EP00108679A patent/EP1048424A3/fr not_active Withdrawn

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