DE10330755B4 - Molded part of wood-based material and method of manufacture - Google Patents

Abstract

molding made of wood-based material, in particular wood-based panels, which has a wood chip or fiber pulp and a particulate plastic binder containing under pressure and heat are pressed, wherein the binder is a low-melting plastic made of comminuted plastic, in particular of films, which is admixed with particles of wood chips and / or pulp, characterized in that the wood chip and / or pulp a filler mixed in the form of fibrillated or ground agglomerate of mixed plastic is, taking the size of the wood particles and at least the mixed plastic particles of approximately the same order of magnitude lies.

Description

The The invention relates to a molding of wood-based material, in particular a wood-based panel, according to the preamble of the claim 1.

at Wood-based panels are differentiated from other wood-based panels between wood chipboards and wood fiber boards. Be fiberboard made of frayed wood, depending on the fiber fleece formation in the aqueous or gaseous Medium, the production by the wet or dry process carried out becomes. The shredding of the pre-shredded wood (chips) takes place after hydrothermal pretreatment in a disc refiner. The pulp is dry-process synthetic binders added. After the fiber web formation, the wood fiber boards are submerged Application of heat and pressure pressed. Fibreboard mostly coated, in furniture and interior design, in interior doors, for packaging purposes and also in construction extensive application. Become porous wood fiber boards for heat and Schalldämmzwecke used.

at Chipboard will be similar to wood chips in the wood fiber board with a binder made of synthetic resin glue, e.g. Urea, phenol, melamine-formaldehyde resins, PMDI adhesives etc., pressed warm. By size, shape and arrangement of the chips and the amount of resin content can change the properties of Wood chipboards are varied. High quality panels can be multilayered and with very fine shavings getting produced.

Next the mentioned Raw materials used in the production of wood-based panels contain water repellents, Harder and add other additives. At the cost of materials for the preparation of such Wood materials, the binder has the largest share before that for the wood raw material.

In the DE 103 26 181 A1 the substitution of wood material by comminuted plastic agglomerate is described. The agglomeration of mixed plastics is a common form of treatment in the disposal and recycling of plastic waste. In this case, by stirring in an agitator, the shredded plastic residues, in particular films, heated by friction so that they melt. By spraying the heated agglomerate with cold water at intervals, some of the organic components escape via the water vapor. At the same time, the molten plastic residues cool and agglomerate into pourable granulate-like structures. Such an agglomerate has a relatively high bulk density and is easy to transport.

From Mixed plastics are spoken when incurred in collection systems Plastics made of different varieties with different Assemble melting point. This results for the mixed plastic a melting range large Bandwidth. An immediate reuse for the production of Plastic parts is problematic because of the large melting window either low-melting plastics during plasticizing already verschmoren or plastics with a higher melting temperature range do not even melt or become fluid. Therefore, one is 1: 1 recovery of recycled plastic, especially mixed plastic, problematic. Because it is difficult with conventional sorting measures an absolute separation of pure plastic and mixed plastic too get the recycle bumps of plastic collected in collection systems to great difficulty.

Out DE 40 18 433 A1 It has become known to produce moldings of wood-based material, wherein a wood chip or fiber mass, a binder is added, which is formed from a low-melting plastic. The plastic is shredded plastic material, in particular sheet material, which is mixed with the particles of wood chips and pulp.

Of the Invention is based on the object, a molding of wood-based material, In particular, a wood-based panel, to create that with a less effort in the use of materials.

These The object is solved by the features of claim 1.

at the molded part according to the invention If the binder is formed by low-melting plastic, in the form of comminuted plastic agglomerate, in particular Foam agglomerate admixed with wood chips or fiber pulp. The melting temperature range of the low-melting plastic can reach 180 ° C or something about it extend. Preferably, low-melting plastic with used a melting temperature range up to 130 ° C. The size of the plastic particles is in the same order of magnitude like the wood particles.

From special collection systems only plastic films can be collected and processed into agglomerate. With an LDPE content of 80%, the melting range extends to 130 ° C. However, it is also possible to get one clearly allow wider melting temperature range when using mixed plastic agglomerate, namely from 100 to about 180 ° C.

at Use of crushed agglomerated mixed plastic as Binder finds both a connection between the individual not melted plastic particles with each other as well as a Connecting the unmelted plastic particles with the wood particles instead of. It is essential that the Introducing the temperature and the pressure is controlled so that the molding blank in the press is still heated sufficiently inside.

To An embodiment of the invention is the ratio of filler to low melting Plastic 10: 90 to 95: 5. High proportion of mixed plastic agglomerate The mixed plastic acts as a filler and at the same time as a means of remuneration, i. as effective against swelling in case of moisture and as protection against wood destroyer.

By a change the added proportions of the various plastic fractions let yourself thus the effect of the plastic agglomerate mixture used in the wood material part in terms of the binder and filler function Taxes. The pure plastic agglomerate melts in the hot press to the middle of the molding and acts as a binder for the not melted Mischkunststoffagglomeratanteile and the wood material.

By the addition of low-melting plastic therefore becomes conventional Binders, e.g. Urea, melamine, phenolic or isocyanate resins (PMDI), replaced. About that In addition, a water repellent and other means for Saved improvement in insect and fungal resistance. Mischkunststoffagglomerat is about it In addition, a little expensive substitute for wood raw material.

The inventive method for producing a molded part of wood material, in particular a wood-based panel is made by mixing crushed Wood particles with crushed agglomerate of low melting point Plastic and the subsequent Hot pressing to the molding. Wood particles, namely shavings, fibers or the like, which are used for the production of the wood material, have one size up, which the size of the crushed Plastic corresponds. The crushing of the low-melting Plastic is in the usual Milling process, taking care must become, that the Temperature during the Mahlvor gangs below the melting temperature of the plastic is. It is also conceivable, the low-melting plastic or Mischkunststoffagglomerat in a Scheibenrefiner to shred or to shred, if Care is taken that the process temperature is below the melting temperature of the plastic. film residues or agglomerate of these are usually molecule-oriented in one direction. This is based on the stretching of the produced plastic films in one direction. This property favors the fraying of the agglomerate in a disc refiner.

To An embodiment of the invention is during the mixing of wood particles and plastic particles cold glue added, especially urea. This results in a certain binding of the shares to each other, so that the Transport in the press arrangement, in particular during the dry process, is relieved. For the later ones Properties of the molded part produced plays the added cold glue not matter.

The Mixing is preferably carried out in a gluing drum.

below examples for Molded parts made of wood-based material according to the invention also for the inventive method.

Example 1:

chipboard with d = 13 mm: For the cover layer 100% (based on Spanmasse atro) ground Mischkunststoffagglomerat with KG 1.0 mm-4 mm, for the Middle layer 100% (based on Spanmasse atro) ground film agglomerate with KG 1.0 mm-4 mm.

Example 2:

chipboard with d = 4 mm: 150% (based on span mass atro) milled mixed plastic agglomerate with KG 1.0 mm-4 mm or ground film agglomerate with KG 1.0 mm-4 mm at mixing ratio 1: 1 (mixed plastic: foil).

process technology

Example 1:

Press the mixed mass on a platen press, press surface temperature about 240 ° C at a press time factor of 15 s / mm, plate thickness 13 mm, initial pressure 6 bar

Example 2:

Press the mixed mass on a platen press, press surface temperature about 240 ° C at a press time factor of 15 s / mm, plate thickness 4 mm, initial pressure 6 bar

Claims (12)

Molded part of wood-based material, in particular wood-based panels, a woodchip or pulp and a particulate binder contains plastic, the under pressure and heat are pressed, wherein the binder is a low-melting plastic made of comminuted plastic, in particular of films, which is admixed with particles of wood chips and / or pulp, characterized in that the wood chip and / or pulp a filler in the form of a fibrillated or ground agglomerate of mixed plastic is mixed, the size of the wood particles and at least the mixed plastic particles of approximately the same order of magnitude lies. Molding according to claim 1, characterized that the melting temperature range of the low-melting Plastic up to 180 ° Celsius or something about it extends. Molding according to claim 1, characterized that the melting temperature range of the low-melting plastic extends to 130 °. Molding according to one of claims 1 to 3, characterized that the low-melting plastic from crushed plastic agglomerate, especially pure film agglomerate, mixed plastic shares as fillers is added. Molding according to one of claims 1 to 4, characterized that the ratio of filler and low melting plastic is 10: 90 to 95: 5. Molding according to one of claims 1 to 5, characterized that the particle size of filler and wood particles is 0.5 to 4 mm, preferably 1 mm. Molding according to one of claims 1 to 6, characterized that the material by subsequent Heat becomes malleable again. Method for producing a molded part from wood-based material, in particular a wood-based panel in which wood particles and Binder particles of plastic mixed and under pressure and Heat pressed be, with the following steps: Agglomerate of low Melting plastic or mixed plastic with low proportions melting plastic as a binder and agglomerate of mixed plastic as a filler are crushed and mixed with the wood particles of approximately the same size and pressed to the molding by hot pressing. Molding according to claim 8, characterized in that that the heat input in the hot press is set so that the particles are low over melting plastic melt the thickness of the molding away. Method according to claim 8 or 9, characterized that while the mixing of cold glue is added, in particular urea. Method according to claim 10, characterized in that that the mixing is carried out in a glue drum. Use of crushed agglomerate from low melting pure plastic or mixed plastic with shares on low-melting plastic, in particular film residues, as Binder for the production of molded parts, in particular plates.