EP1413695B1 - Supporting plate - Google Patents

Abstract

A laminar floor block (1) has a tongue and groove joint and interlocks with the adjacent block. Each block is fabricated from wood chips with a density of less than 700 k/m pref. 400-650 kg/m and containing more than 10 per cent bonding agent. The bonding agent is a UF resin, MUF resin or less than 20 per cent isocyanate, or a combination of these agents.

Description

The invention relates to a carrier plate of binders and a wood material according to the preamble of claim 1 and a panel with such a carrier plate.

Such a support plate is particularly suitable for a floor panel.

HDF boards with a specific weight of more than 850 kg / m ³ are regularly used as a carrier board in the laminate floor area. Such relatively heavy carrier plates increase transport costs and make laying difficult.

From the DE 196 00 478 A1 there is known a process for producing a lightweight, medium-density fiberboard in which the fiberboard is produced with an average apparent density of less than 550 kg / m ³ of lignocellulosic fibers and polyurethane size as binder. The fibers are mixed with less than 4.0 wt .-% binder based on atro fibers.

The WO 99/66152 A1 describes a locking system for mechanically locking floor panels along a vertical connection plane. On the sides of the floor panel locking means for locking a plurality of support plates are provided with each other in both vertical and in the horizontal direction. The material used can be plywood, plywood or fiberboard.

The WO 92/13688 describes a process for the production of wood fiber boards, in which the raw material subjected to defibration, then glued in a blow pipe with an aqueous binder liquor and the resulting glued fiber material is scattered after drying to the required residual moisture to mat webs and pressed under pressure and temperature to plates. The gluing is carried out with a liquor having a solids content of 20 to 35% by weight, and a quantity of binder is used which amounts to less than 10% by weight of solid resin based on the total amount of fiber material calculated atroute.

The DE 295 21 729 U1 describes a floor covering with a support plate of a wood material and with an intermediate layer which consists of a wood veneer and with a wood veneer protective surface layer, wherein the wood veneer is bonded directly to the support plate. The support plate may be formed from an MDF or HDF material and be provided for flush connection to adjacent surface elements with tongue and groove.

The US 4,268,565 describes a furniture part with contours embossed therein with a base layer of cellulosic fibers and a binder, the base layer has a density in a range of 160 to 561 kg / m ³ , with an integrally formed boundary layer with a density between 641 and 881 kg / m ³ Density.

The US 4,175,150 describes a high density fiberboard with a lower density core, the core having a density between 160 and 561 kg / m ³ , while the density at an outer layer is between 641 and 881 kg / m ³ . The EP 0 262 537 A2 describes an isocyanate polyester for the production of plate-shaped, cellulose-containing components, in particular chipboard, fiberboard or OSB boards. The insert is proposed in fibreboards with a density between 64 and 70 kg / m ³ .

The US 6,376,582 B1 describes a fiberboard and a manufacturing method for a fiberboard. Different binders are provided, for example isocyanates or polyurethane resin. The binder content may be between 3 and 30% by weight, preferably between 8 and 20% by weight, based on the total amount of the acetylated and untreated wood fibers. The density of the fiberboard is for example between 500 and 900 kg / m ³ .

The US 6,006,486 describes a carrier plate for connection to a second carrier plate with means for detachably connecting the two carrier plates, wherein on at least one side edge of the first carrier plate interlocking elements for locking in the vertical direction and / or in the transverse direction are formed with the further carrier plate:

Depp / Emst: " MDF medium density fiberboard "1996, DRW-Verlag , describes basic plate properties of a medium-density fiberboard. In contrast to particle boards, which have a differentiated pipe density profile, MDF boards are preferably produced with a uniform density distribution. In New Zealand, lightweight MDF boards are produced where the aim is to achieve a great differentiation in the density profile between the cover and middle layers, as in the case of a chipboard. With a plate density of 750 kg / m ³ , a minimum gluing value of 7% is provided in the middle layer.

Sonine "wood materials", DRW-Verlag, describes uses of particleboard and fiberboard. Building boards for floors as well as wall and roof have a gross density of around 750 kg / m ³ and optionally isocyanates as a binder. As binder content, 0.5 to 4% are given on atro fibers.

Mombecher "Holzlexikon" DRW-Verlag, defines medium-density fiberboard as fiberboards with a bulk density of more than 350 g / m ² to 800 g / m ³ , which are mainly produced by the dry process in thicknesses between 6 and 25 mm. The plates have a very homogeneous structure, the narrow surfaces are easier to work with than chipboard. The gluing factor is usually 7% in the top layer and 5% in the middle layer.

Böhme "The Importance of the MDF Density Profile", Mobil Oil AG, gives several examples of parabolic density profiles. The density distribution across the cross section has a great influence on the mechanical properties of the finished plate. The aim is to have dense and homogeneous middle layers that facilitate narrow-surface processing and their coating.

The WO 98/24605 A1 describes a method of using recycled lignocellulosic materials which are subjected to high shear forces in a water or steam atmosphere at a temperature between 40 ° C and 120 ° C. At the same time binders are supplied. Typical resinous binders are UF resins, MUF resins, MF resins, PF resins, RF resins, TF resins and PMDI binders, and mixtures thereof. The resins can be used in a range between 5 and 15% based on atro-fibers.

The JP-11291203 A1 describes the production of a woody, decorative plate in which an MDF board is milled or abraded on its one outer side or the MDF board is divided in the middle and the sub-board thus machined with the unprocessed original outer side is glued onto a support plate. A decorative paper is laid over the softer, outer surface of the glued MDF board and glued to the glued MDF part plate. Subsequently, a mechanical embossing is performed, supplemented by a pickling process. The object of the invention is to produce a carrier plate of binders and fillers, which on the one hand is easy to handle and on the other hand has sufficient strength.

According to the invention this object is achieved by a support plate having the features of claim 1 and a panel having the features of claim 3. An advantageous embodiment and development of the invention is described in the subclaim.

Due to the design of the support plate with a density of less than 700 kg / m ³ with simultaneous Beleimungsfaktor greater than 10% is achieved that the support plate has almost plastic-like properties in terms of weight and strength, but the material use due to the embedded wood materials, preferably fibers, essential is lower. The invention provides that the support plate has a non-uniform density distribution over the cross section from the top to the bottom, wherein the top and bottom cover layers have a density in the range of 1000 kg / m ³ , whereas the middle layers in cross section to 400 kg / m ³ to 600 kg / m ^{3 are} compressed. The high density on the top and bottom sides ensures that a high level of resistance to vertical, mechanical stress is achieved, as is required, for example, when using floor panels. A panel with such a carrier plate is provided on the top and the bottom in each case with a finishing layer, which usually consists of a melaningetränkten decorative layer or Gegenzugschicht to additionally protect the carrier plate from mechanical damage. For the customized production of carrier plates depending on the stress and intended use, it is provided that a mixture of isocyanates and UF or MUF resins is used as gluing of the wood materials or fibers and the carrier plate.

A further embodiment provides that the carrier plate has a density between 400 kg / m ³ and 650 kg / m ³ , whereby an optimal strength in relation to the density and the use of material is effected.

Due to their high heat resistance, isocyanates also offer the possibility of achieving higher gluing factors. Also, by the addition of isocyanates, the strength is maintained during a heat-intensive coating of the backing plate, since the exclusive use of urea resins tends to cause the backing plate to lose strength during coating.

Due to the weight savings of specific lighter carrier plates transport costs are reduced and beyond a previously unknown flexibility of the support plate is realized by the special profile configurations, especially in so-called click connections, are possible.

In addition, the increase of the gluing factor leads to an improved moisture resistance, since the reduced proportion of wood material in the plates reduces the tendency for the carrier plate to swell. Usually, the penetration of moisture in the region of the connection points of two support plates or two floor panels leads to a swelling of the support plates in this area and thus to a destruction of the floor. The carrier plate according to the invention and a floor panel made therewith are suitable due to the lower swelling tendency (less than 5%), especially for use in damp rooms.

In addition, due to the differently densified layers within the carrier plate, there is a refraction of the sound waves at the density transitions, so that the impact and room sound is significantly reduced.

Figur 1 -

ein Paneel in Querschnittsansicht; sowie

Figur 2 -

eine Dichteverteilung über den Querschnitt einer Trägerplatte.

The invention will be explained in more detail with reference to the accompanying figures. Show it:

FIG. 1 -

a panel in cross-sectional view; such as

FIG. 2 -

a density distribution over the cross section of a carrier plate.

FIG. 1 shows in cross section a floor panel 10 with a support plate 1, on the top 15 and bottom 5 each have a final layer 16, 6 is applied. The final layers 16, 6 are applied to the outer end of the support plate 1 forming cover layers 7, 17, preferably glued and protect the support plate 1, for example, against moisture and mechanical stress. Likewise, these end layers 6, 16 may have a decor and increase the mechanical stability of the floor panel 10.

On the side edges of the panel 10 locking means 2, 3 are formed which prevent a relative movement of two interconnected panels both in the vertical direction V as a transverse direction Q. The carrier plate 1 is made of a fiber material, which is usually used for the production of HDF boards, alternatively or additionally other wood materials are incorporated. In contrast to the core 20 of the carrier plate 1, the cover layers 7, 17 of the carrier plate 1 have a substantially higher density, with densities of up to 1000 kg / m ^{3 being achieved} in the cover layers 7, 17. Within the core 20, the density decreases continuously to the center M of the support plate 1, wherein a corresponding density distribution over the thickness d of a support plate 1 in the FIG. 2 is shown. It can be seen that the lowest value for the density ρ in the center M of the carrier plate is achieved, while the thickness d of the carrier plate from the center M, starting from the Density ρ is increased in order to reach its maximum on the surfaces of the cover layers 7, 17.

Due to the extremely high density in the cover layers 7, 17 in the range of 1000 kg / m ³ , the support plate 1 is given the necessary resistance to vertical, mechanical stresses, in combination with the use of UF or MUF resins, in admixture with Isocyanates, a special flexibility is generated within the plate. The addition of isocyanates improves the moisture resistance of the carrier plate 1, so that the essential properties of the carrier plate 1 are determined by the resins used or introduced plastics.

Claims (3)

1. Supporting plate, in particular for a floor panel, comprising at least one binder for binding fillers made of a wood-based material, the supporting plate (1) being provided with means for releasable connection to at least one further supporting plate (1), positive locking elements (2, 3) being formed on at least one side edge of the supporting plate (1) for locking in the vertical direction (V) and/or in the transverse direction (Q) to the further supporting plate, the supporting plate (1) having an irregular density distribution over the cross-section from the upper side (15) to the lower side (5), characterised in that the supporting plate (1) has a density of less than 700 kg/m³ and a layer (16) with a density of 1,000 kg/m³ is present at the upper side (15) and/or the lower side (5) of the supporting plate (1), while a density of 400 kg/m³ to 600 kg/m³ is present in the centre (M) of the supporting plate (1) and the bonding factor of the supporting plate (1) is greater than 10 % by weight binder based on absolutely dry fibres and the bonding agent of the fibres of the supporting plate (1) is a mixture of isocyanates and UF or MUF resins.
2. Supporting plate according to claim 1, characterised in that the supporting plate (1) has a density of between 400 and 650 kg/m³.
3. Panel (10) with a supporting plate (1) according to any one of the preceding claims, characterised in that the supporting plate (1) in each case has a sealing layer (6, 16) arranged on an upper side (15) and a lower side (5) of the supporting plate (1).

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