WO2022194419A1

WO2022194419A1 - Self-stabilised substrate laying unit, substrate covering, and method for laying such a substrate laying unit

Info

Publication number: WO2022194419A1
Application number: PCT/EP2021/087764
Authority: WO
Original assignee: Weitzer Holding Gmbh
Priority date: 2021-03-18
Filing date: 2021-12-29
Publication date: 2022-09-22
Also published as: EP4060141A1; EP4060141C0; EP4060141B1

Abstract

The invention relates to a substrate laying unit (100), in particular a floor panel or a wall panel, for floating installation on a substrate (200), the substrate laying unit (100) comprising: i) a wear layer (110) having a wood veneer, the wear layer having a first preferred direction (R1); ii) a stabilisation layer (120) having a material which exhibits substantially no swelling and shrinking behaviour in the event of a change in humidity; iii) a first support layer (130) having a second preferred direction (R2); iv) a second support layer (140) having a third preferred direction (R3); and v) a connecting structure (150) which is configured to provide a detachable connection to the substrate (200). The preferred directions (R1, R2, R3) are coordinated such that, in the event of changes in humidity, the substrate laying unit (100) is substantially self-stabilised with respect to swelling and shrinking behaviour.

Description

SELF-STABILIZING UNDERFLOOR UNIT, UNDERFLOORING AND METHOD OF INSTALLATION OF SC LCHEI UNDERFLOOR UNIT

Technical field of the invention

The invention relates to an underground laying unit, in particular a floor panel or a wall panel, for floating laying on an underground. The invention further relates to an underground covering which has the underground laying unit. Furthermore, the invention relates to a method for laying an underground covering.

The present invention can thus relate to the technical field of subfloor coverings, in particular multi-layer parquet coverings.

Technical background

Parquet and other wood-based panels are popular and efficient floor or wall coverings, but are generally relatively expensive to install. In addition, wood as a material reacts strongly

Moisture changes (literally "wood works") and thus shows a pronounced swelling and shrinking behavior, which can lead to bulges and cracks in the floor or wall covering. To counteract this, parquet panels are usually glued to the subsurface and rigidly fastened to one another with connecting elements However, this results in a high expenditure of time and money when renovating or replacing such floor or wall coverings.

WO 2012/156192 describes a surface-laying unit for laying with other surface-laying units on a substrate, in particular an underground-laying unit, the surface-laying unit having a wear layer and a connection structure attached directly to an underside of the wear layer, which is set up for connecting to the ground.

EP 3 070 231 A1 relates to an underground laying unit for laying with other underground laying units for covering an underground, the underground laying unit having an underground-side fastening structure which is designed for fastening to the underground, and a plug-in connection structure facing away from the underground for detachable plug-in connection with a having a correspondingly designed plug-in connection structure of a surface-laying unit.

However, laying and replacing a parquet panel according to WO 2012/156192 or EP 3 070 231 A1 still requires quite a lot of effort because it is absolutely necessary to provide complex underground laying units, on which the surface laying units can then be fastened. This is due in particular to the fact that the surface laying units as such are exposed to high (internal) stresses and are therefore not self-stabilizing.

Summary of the Invention

It is an object of the present invention to allow underground installation units to be laid on an underground in a resource-saving, environmentally friendly, flexible manner, with little effort and at the same time reliably and protected from undesired high (residual) stresses.

This object is solved by the objects with the features according to the independent patent claims.

According to one aspect of the present invention, an underground installation unit (in particular a floor panel or a wall panel or a ceiling panel) for floating (e.g. adhesive-free) installation on an underground (e.g. on an underground connection structure, directly on a screed, etc.) is described, wherein the Underground laying unit has: i) a wear layer, which has a wood veneer (in particular a real wood veneer), the wear layer having a (first anisotropy property and thus a) first preferred direction; ii) a stabilization layer (eg a glass fiber mat) which comprises a material which (substantially) exhibits no swelling and shrinkage behavior in the event of a change in humidity (thus eg no wood veneer); iii) a first base layer (eg another wood veneer) which has a (second anisotropy property and thus a) second preferred direction; iv) a second base layer (eg another wood veneer) which has a (third anisotropy property and thus a) third preferred direction; and v) a connection structure (e.g. a magnetic foil, a mechanical latching mechanism, etc.) which is configured to provide a detachable connection to the subsurface.

In this case, the preferred directions are matched to one another in such a way that the underground installation unit is (essentially) self-stabilized in the event of changes in moisture with regard to the swelling and shrinkage behavior.

According to a further aspect of the present invention, an underground covering is described which comprises: a plurality of underground laying units as described above. Here, the underground-laying units of the plurality of underground-laying units are laid floating on the ground and free of front-side connecting elements (therefore the underground-laying units are not connected to one another by additional connecting elements).

According to a further aspect of the present invention, a method for laying underground laying units is described, the method comprising: i) providing a plurality of underground laying units as described above; ii) providing an underground connection structure (e.g. a counterpart to the connection structure) on the subfloor (e.g. a screed); iii) Laying the plurality of underground laying units (free of connecting elements among themselves) in such a way that the connecting structures (of the underground laying units) are detachably coupled to the underground connecting structure (or a plurality of underground connecting structures) (and thereby providing an underground covering as described above) ; iv) releasing the coupling between at least one of the connecting structures and the underground connecting structure (or the plurality of underground connecting structures) in order to remove at least one of the underground laying units; and v) replacing the at least one underground laying unit (which e.g. is already worn out) with another underground laying unit (which e.g. is not yet worn out).

In the context of this description, a "underground laying unit" can be understood in particular as a multi-layer module (in particular multi-layer parquet module), the wear layer of which is on or laid over a substrate is exposed or visible to the outside (possibly still covered with an optional protective coating). The laying of the underground-laying unit can take place, for example, by means of the connection structure on the underside of the underground-laying unit with a ground. The term underground laying unit is to be understood as meaning that it can be laid on any flat surface, for example a horizontal surface (in particular a floor, wall or ceiling surface), an inclined surface (in particular a ramp) or a vertical surface (in particular a Wall surface) can be laid. The underground laying units can be manufactured in practically any format. This includes in particular any quadrangular configuration, further in particular rectangular arrangements (panels). However, other shapes, such as polygons, are also possible.

In the context of this description, a "parquet" can be understood as a subfloor for rooms that has wood. The wood, usually hardwood from trees, can be sawn into small pieces and assembled according to certain patterns "Laminate flooring", because laminate flooring consists of wood fibers as a carrier and is coated with melamine resin, whereby the visible wooden surface consists of a laminated paper layer with a wood pattern (decorative layer impregnated with melamine resin).

In the context of this description, a "wear layer" can be understood in particular as a layer near the surface or a surface layer or a board on which the actual mechanical and / or chemical stress on the laid floor or wall covering takes place Wear layer can be that which a user uses as a floor to walk on. In the context of this description, a wear layer can be a "board-like rigid layer" which has the mechanical properties of a board. Such a layer cannot be wound up on a roll, for example. According to one embodiment, the top layer can be made of solid wood (real wood veneer). Thus, according to this exemplary embodiment, the wear layer can consist solely of wood as a component. It can be made of solid wood, for example.

European types of wood that are processed into layers of the sub-base laying unit (especially the wear layer or base layers). are, for example, oak, beech, maple, birch, walnut, cherry, ash, olive, acacia, elm, apple tree, pear tree, larch, stone pine and sweet chestnut. Non-European types of wood that can be used are, for example, merbau, wenge, teak or mahogany.

Due to the wood fibers and their orientation, wood generally has anisotropy and a preferred direction. In principle, a distinction is made: i) longitudinal (alignment of the fibers), ii) radial (across the fiber direction and across the annual rings), and iii) tangential (across the fiber direction and along the annual rings), whereby in this document the fiber direction (longitudinal , i) can be called the preferred direction.

In this description, the term "swelling and shrinkage behavior (or swelling and shrinkage)" can refer in particular to the fact that the volume of wood increases or decreases with changes in moisture content. Simply put, wood can expand or shrink. Swelling and shrinkage can be characteristic values for the hygroscopic properties of wood and wood-based materials that describe the dimensional change of a workpiece depending on the wood moisture content.The shrinkage value is the change due to the reduction in the moisture contained (shrinkage), while the swelling value is the change due to moisture absorption (swelling) .

The swelling and shrinking behavior acts in particular along the three directions outlined above. In general (e.g. for oak) there is a ratio i:ii:iii of 1:10:17 for the swelling and shrinking behavior. All types of wood have their specific swelling and shrinking behavior, but in general it can be said that softwoods are usually less shrink more than hardwoods, for example, the wood of oak and beech shrinks more than that of spruce and pine. A common method for determining swelling and shrinkage is described in the DIN 52184 standard.

In principle, this can be done as follows:

1. The swelling and shrinking behavior is based on a specific wood moisture content range, as the progression is not linear.

2. With general values such as the 1:10:20 rule of thumb (rough reference value for all types of wood and moisture levels) one usually speaks of the range 0% - FSB (fiber saturation range, depending on the type of wood, is around 25 - 30%) . 3. Creating a wood sample with defined dimensions and corresponding fiber orientation, bringing this to the desired wood moisture content, checking it using the kilning method, measuring the sample and comparing the measured dimensions.

Another definition is the differential swelling and shrinkage in %/%, i.e. % dimensional change per % moisture change. This can also be seen as a guide value, because the progression over the humidity is not linear.

In conjunction with the swelling and shrinking behavior, wood panels can also curve outwards (convex) or inwards (concave) (so-called cupping) when laid when the moisture content changes (so-called cupping), see Figures 3 and 4 below.

In the context of this description, a “stabilization layer” can be understood in particular as a layer or a board that is far from the surface, which serves to stabilize the laid floor or wall covering as a whole. The stabilization layer preferably has (essentially) in the event of moisture changes (essentially), unlike e.g. wood veneer, no swelling and shrinkage behavior. In one example, the stabilization layer (essentially) has no wood or less wood than a wood veneer. For example, the stabilization layer can have a plastic or a metal, because these materials show (essentially) no swelling and shrinkage behavior. In one example, the stabilization layer has an anisotropic property and a corresponding preferred direction. This is the case, for example, when the stabilization layer has fibers, e.g. a glass fiber-reinforced plastic mat. However, the stabilization layer can also have an isotropic dimension material, e.g. be designed as aluminum foil.

In the context of this description, a "base layer" can be understood in particular as a surface-distant layer or a board that increases the stability of the underground laying unit. A base layer can act as a barrier layer and/or as a counteracting layer. In one example, the base layer has a wood veneer, however, other configurations are also possible, eg plastic or metal However, this should be implemented in such a way that there is a preferred direction in order to act as a barrier layer and/or as a counteracting layer in conjunction with the useful layer. In the context of this description, a "connection structure" can be understood in particular as any physical structure that is specially adapted to enter into a connection with the intended neighboring element (e.g. an underground connection structure or a counterpart), ie to exert a fastening force on it. A connection structure can be designed as a layer or as one or more specially attached elements.The laying of the underground installation unit can be carried out, for example, by means of an additional connection structure on the underside of the underground connection structure and/or by means of an additional connection structure on the upper side of the underground.Also a floating laying of the subsurface connection structure on the subsurface is possible (eg with a magnetic foil).

In the context of this description, the term "subsoil" can refer to a "subsoil". Furthermore, the term can also include an "underground floor" with an additional "underground connecting structure". A "subsoil" can be understood in particular as any flat or essentially flat surface that can be covered with subsurface laying units. The subsoil can be a subsoil of a building (e.g. a building floor, a building ceiling or a building wall), i.e. an on-site subsoil However, it is also possible to use stairs or staircases (in particular horizontal and/or vertical surfaces of steps) as the sub-floor. Sub-floor can include the following, for example: screed, wooden floor, tiles, laminate, PVC covering, carpets, etc.

In the context of this description, a "top" of a layer or an element can be understood in particular as a main surface of this layer or this element, which faces away from the substrate when this layer or this element is laid as intended. Correspondingly, a "bottom" of a layer or of an element, in particular such a main surface of this layer or this element is to be understood that faces the substrate when this layer or this element is laid as intended.

In the context of this description, the term "floating installation" can be understood in particular to mean that an underground installation unit is reversibly, ie non-destructively detachable, installed on an underground such a reversible laying can be realized, for example, via magnetic elements, snap-in elements or no connection at all. A connection using a special easily detachable adhesive (eg without leaving any residue) is also conceivable. However, the term "floating laying" does not include conventional adhesives (e.g. silane-modified parquet adhesive (SMP) or PUR adhesive), which do not allow the sub-floor laying unit to be detached without leaving any residue.

In the context of this description, a "releasable connection" of two elements by means of a connection structure can be understood in particular as meaning that after such a connection has been formed, it can be released again in a reversible and non-destructive manner by applying a releasing force. Such non-destructive release means that the connection structure can be reused after release be reused, in particular at least ten or at least a hundred times, without the connection function suffering or being impaired as a result.

In one exemplary embodiment, the application of a release force of less than 200 N, in particular less than 100 N, more particularly less than 50 N, can be sufficient for such a release. In order to avoid undesired detachment of the laid covering, the detaching force should be at least 10 N, in particular more than 20 N, more particularly more than 30 N. However, the forces can also have other magnitudes.

According to an exemplary embodiment, the invention can be based on the idea that laying underground installation units on an underground resource-saving, environmentally friendly, flexible, with little effort and at the same time reliable and protected from unwanted high (residual) stresses is possible if a self-stabilized underground installation unit with a very special layer structure is used.

For this purpose, a barrier structure is selected in which the preferred directions of a wear layer and two base layers are selected in relation to one another in such a way that unwanted stresses due to the swelling and shrinking behavior with changes in humidity are blocked. A stabilization layer is now introduced under the wear layer and above the base layers, which does not show any swelling or shrinking behavior and This enables optimal self-stabilization of the underground installation unit.

Conventionally, damage caused by changes in humidity is counteracted by firmly (non-detachably) gluing thick parquet panels to the subsurface and hooking them together with connecting elements. However, this ultimately leads to many disadvantages in terms of costs and workload.

However, it has now surprisingly been recognized by the inventors that a particularly thin underground laying unit (which nevertheless has a stable wooden wear layer) can be laid in a simple, inexpensive and flexible manner (without connecting elements) in a floating manner, with this underground laying unit stabilizing itself (and thus free of internal stresses) compared to the swelling and shrinkage behavior and bulges with changes in humidity (see, for example, the particularly small bulges in Figures 3 and 4). In particular, through the targeted provision of the stabilization layer, self-stabilization can be achieved, which has a similar effect to gluing. As a result, the latter is superfluous and a simple, resource-saving exchange of underground laying units is possible.

Exemplary implementation examples

According to an exemplary embodiment, the underground laying unit is free on all front sides (long sides and width sides) from connection elements to further underground laying units. This can bring the advantage that material and production costs can be saved and the necessary stability is still given. In particular, this new type of laying with distribution can create a completely different feeling when walking, e.g. because the underground laying units can be moved vertically.

Conventionally, subfloor laying units such as parquet panels on the front sides become further units with connecting elements

Sub-base laying units provided to provide a robust connection and thus a stable sub-base. These connecting elements usually include click-in or snap-in mechanisms based on the tongue and groove principle. Most fasteners are made of wood or wood scraps, however these can also have metal or plastic, for example. It is therefore necessary to click or snap in for attachment, and this is usually on all end faces. In the case of a floor panel, there are two long sides and two width sides. However, other shapes with more end faces are also conceivable. These connecting elements (in a simple or very complex structure) are so widespread that a stable panel structure does not seem possible without them.

However, the inventors have now surprisingly recognized that such a connection-element-free structure is made possible in a stable and robust manner by using the described self-stabilized underground laying unit.

According to a further embodiment, the connection structure has at least one from the group consisting of: a magnetic layer, a magnetic foil, a magnetic mat (e.g. an iron mat), a plurality of magnetic elements (e.g. individual permanent magnets), a snap connection, a click -connection, a plug-in connection, a tongue and groove connection, a Velcro mat, a detachable adhesive layer (e.g. double-sided adhesive tape), an electrostatically charged mat (whereby the charge carriers can be enclosed inside such a mat), a slip mat (e.g. made of a rubber material with high static friction), a spray or brush layer and/or an arrangement of suction cups.

This can have the advantage that a large number of different connection options are made possible depending on the existing conditions. Magnetic, mechanical, electrical forces or a combination thereof can be used to realize the detachable or reversible connection characteristic between underground laying unit and underground (connecting structure). It can thus also be formulated that the connection structure is set up to provide a magnetic, mechanical or electrical connection.

The connecting structure can be permanently attached to the support layer, in particular sprayed on as a dry spray fluid, applied as a dry paint, or laminated, welded or glued to it as a flexible or rigid solid. For example, a magnetic layer can be applied to the wear layer as a liquid suspension of magnetic particles (e.g. colloids or magnetic filings) and a solvent, etc. After the suspension has dried, a thin magnetic layer that can be produced at low cost then remains on the wear layer. The bonding structure may also include a hot melt adhesive. A hot melt adhesive is applied in a molten form and then adheres to the surface when cooled again to a temperature below the melting point.

According to a further exemplary embodiment, the underground laying unit has a thickness of 10 mm or less, in particular 5 mm or less, in particular 4.8 mm or less, in particular 4.5 mm or less, in particular 4.2 mm or less, in particular 4 mm or less fewer. As a result, material can be saved and the underground laying unit can be laid particularly flexibly without the height of the floor structure becoming too great.

Compared to known floor panels, this construction height (with at least five layers including a wood veneer wear layer) is extremely low. It is extremely surprising that such a thin multi-layer panel is still strong enough to withstand the stresses that a subfloor is subjected to in everyday use.

According to a further exemplary embodiment, the connection structure has a thickness of 2 mm or less, in particular 1.5 mm or less, in particular 1 mm or less, in particular 0.8 mm or less.

According to a further exemplary embodiment, the wear layer has a thickness in the range from 0.2 to 1.1 mm, in particular in the range from 0.4 mm to 0.9 mm.

In this way, too, material can be saved and the underground laying unit can be laid particularly flexibly without the height of the floor structure becoming too great. Compared to known floor panels, these thicknesses are very small and it is surprising that the desired functions of tread stability or stability of connection to the subsurface are still efficiently and robustly enabled despite the small thickness.

According to a further exemplary embodiment, the first base layer and/or the second base layer has another wood veneer. In particular, at least one of the wood veneers has a real wood layer (or solid wood layer, solid wood layer). This can have the advantage that a tried and tested product can be used directly. In the case of the wear layer a layer of real wood gives a particularly positive visual impression in addition to the advantages of stability (and ease of care). A wood veneer layer can have a particularly stabilizing effect on the base layers.

A particular advantage can result if both the wear layer and at least one of the base layers use a wood veneer, in particular from the same type of wood. As a result, both layers show a similar, in particular the same, swelling and shrinking behavior when there is a change in humidity. Accordingly, the preferred directions can act on one another in a particularly efficient, self-stabilizing manner.

According to a further exemplary embodiment, the first preferred direction and the third preferred direction are arranged (essentially) parallel to one another. According to a further exemplary embodiment, the second preferred direction is arranged (substantially) perpendicular to the first preferred direction and the third preferred direction. This can result in an advantageous blocking effect, which acts efficiently for self-stabilization, even in the case of strong humidity and/or temperature fluctuations. The thicknesses of the wear layer and the base layers and their materials can be matched to one another in such a way that the desired blocking effect is achieved.

According to a further exemplary embodiment, the stabilization layer has a fourth preferred direction. In particular, the fourth preferred direction is (substantially) arranged perpendicular to the first preferred direction (and parallel to the second preferred direction). This can result in the advantage that a further blocking effect or self-stabilization can be individually/flexibly introduced directly below the wear layer.

According to a further embodiment, the stabilization layer has at least one from the group consisting of: a resin matrix (e.g. PUR, EPI, etc.), a fiber material, a fiber-reinforced plastic, a viscose matrix, a metal foil, in particular one Aluminum foil, a mineral-bound fibreboard, a material with a high modulus of elasticity compared to the wear layer, an anisotropic material. There are thus a large number of possibilities for selecting the stabilization layer in such a way that the properties desired in each case can be obtained.

In the case of plywood, one usually thinks of the anisotropy (different properties in the different directions of the coordinate system) as Uses wood and blocks warping. According to an exemplary embodiment of the invention, this effect is intensified by a likewise anisotropic glass fiber mat that is precisely matched to the warping properties of the wood. The tension fiber is therefore not used in the classic way as a "counter-tension" (in the case of a symmetrical structure, the tensile force of the wear layer (e.g. oak) should be balanced) but as a supporting layer of the first base layer (this corresponds to a plywood cross layer).

The stabilization layer can be matched to the warping properties of wood veneer (e.g. sliced hardwood veneer) by means of different grammages in the longitudinal and transverse direction in order to reduce the swelling and shrinkage behavior to a minimum in addition to the conventional transverse layer (first base layer). In particular, the stabilization layer can be provided in such a way that the anisotropy is less pronounced than with wood. This provides a large number of adjustment and optimization options.

According to one exemplary embodiment, warpage optimization or prestressing can be accomplished through the targeted introduction of moisture. In addition, an increase in hardness can be made possible by introducing the stabilization layer (e.g. glass fiber mat).

According to one embodiment, the stabilization layer can directly adjoin the useful layer. In this case, their stabilizing effect is particularly pronounced.

In one embodiment, glass fiber (e.g., in a plastic matrix) has an anisotropy of about 10:13. Here, the preferred direction can be aligned across the grain of a wood veneer layer (e.g. oak). However, a glass fiber with a uniform distribution, i.e. 1:1, can also be used. However, this would still be anisotropic since it does not have any fibers in the thickness. In an exemplary embodiment, the blocking effect of the glass fiber also applies to the wear layer (e.g. oak) and the base layer underneath (e.g. birch). Because of this, the glass fiber can now have almost equi-alignment between longitudinal and transverse.

According to a further exemplary embodiment, the underground laying unit also has: a connecting layer which is arranged between the first base layer and the second base layer. In particular, the connecting layer has an adhesive and/or a natural resin. By means of the connecting layer can be used in a flexible way a robust attachment Base layers can be accomplished together. The bonding layer can advantageously be chosen in such a way that desired properties can be obtained.

According to a further exemplary embodiment of the subsurface covering, at least one of the laid subsurface laying units is (at least partially) movable in the vertical direction. This has the particular advantage that a completely new feeling of walking can be provided, although material and production costs are saved.

According to a further exemplary embodiment, the subsurface covering also has: a subsurface connecting structure (in particular a subsurface connecting layer) which is laid on the subsurface and which is (or can be) releasably connected to the connecting structure. This can bring the particular advantage that the underground laying unit can be exchanged in a quick and practical manner. Instead of re-laying the entire floor (as is usual with conventional parquet panels), each sub-floor laying unit can now be replaced individually.

According to a further exemplary embodiment of the subsurface covering, the connection structure has a magnetic layer, and the subsurface connection structure has a further magnetic layer which is laid floating on the subsurface. This describes a particularly advantageous construction, in which the subsurface connection structure can also be laid in a floating manner (figuratively: simply roll out the magnetic foil). A structure that is as thin as possible is thus realized, in which material and production costs are saved at the same time.

According to a further exemplary embodiment, the total path of the swelling and shrinking behavior or the curvature of the underground laying unit when changing between a humid climate and a dry climate is 0.15 mm or less, in particular 0.1 mm or less, more particularly 0.08 mm or less.

Brief description of the figures

Exemplary embodiments of the present invention are described in detail below with reference to the following figures. FIG. 1 shows a cross-sectional view of an underground laying unit and an underground according to an exemplary embodiment of the invention.

FIG. 2 shows a cross-sectional view of an underground installation unit according to a further exemplary embodiment of the invention.

FIG. 3 clearly shows the swelling and shrinkage behavior of an underground laying unit according to an exemplary embodiment of the invention in a humid and dry climate (change in humidity).

FIG. 4 clearly shows the overall path of the swelling and shrinking behavior of the underground laying unit according to an exemplary embodiment of the invention in a humid and dry climate (change in humidity).

Identical or similar components in different figures are provided with the same reference numbers.

Detailed description of exemplary embodiments

According to an exemplary embodiment of the invention, the following structure is selected:

1) Real wood wear layer (wood veneer) with a thickness in the range of 0.4 mm to 0.9 mm (minus any brushing).

Function: Visually appealing surface, backing layer for surface coating, resistance to impact and pressure loads.

2) Stabilization layer: Glass fiber roving fabric, in terms of grammage and thread thickness matched to the warping behavior of the real wood wear layer, integrated in a synthetic resin matrix (EPI or PUR).

3) First base layer: real wood veneer layer aligned across the real wood wear layer (birch peeled veneer 1.5 mm or oak sliced veneer 0.9 mm).

4) Bonding layer: adhesive, e.g. one of PUR, EPI, PVAC.

5) Second base layer (balancing veneer): real wood veneer layer aligned lengthwise/parallel to the real wood wear layer (birch peeled veneer 1.0 mm or oak sliced veneer 0.9 mm).

According to an exemplary embodiment of the invention, a special sandwich structure is selected, which for the first time enables a (real wood) Lay the subfloor with a total structure thickness of < 3 mm without connecting elements (longitudinal and transverse) "floating" with a comparable swelling and shrinking behavior (with changes in humidity) as is usual with classic multi-layer parquet. The sandwich structure is a new type of engineered wood product that uses a stabilization layer that is not necessarily cellulose-based in order to "lock off" the swelling and shrinkage behavior of the wear layer, although the stabilization layer does not act as a counteract.

According to an exemplary embodiment of the invention, the properties of different types of wood and those wood veneer layers of different thicknesses, which can also differ in the manufacturing process (e.g. peeled veneer and sliced veneer), are used to direct the tendency to warp/curvature (concave/convex) into a convex cupping ( in addition to blocking swelling and shrinkage).

According to an exemplary embodiment of the invention, a variable introduction of water through different water contents in the glued joints, such as is achieved, for example, by adding water or different adhesive systems (EPI/PVAc/PUR), can be used to advantage.

This inhomogeneous introduction of water initiates stresses in the multi-layer structure during the pressing process, which means that the initial distortion (slight prestress in the convex direction) can be provided as desired.

According to an exemplary embodiment of the invention, possible adjustments when the stabilization layer is provided are:

- Grammage: How many g/m ² glass fiber material is processed in the respective direction (longitudinal/transverse). High grammages result in higher rigidity, provided that all fibers are well embedded in the adhesive.

- Thread thickness: Thickness of the threads given in tex. Thinner threads (eg in the range of 110 to 150 tex, in particular 130 to 140 tex, at about 100 g/m ² ) with the same grammage enable better glue penetration. Thinner threads create better glue penetration and binding and thus compensate for the lower grammage. Thicker threads increase bumpiness and reduce fiberglass-to-wood bonding.

- A more open structure allows for better glue penetration but increases unevenness. - Post-processing ("burning") of the glass fiber reduces "contamination" and increases the adhesion of the glue to the fiber.

- Adhesives: White glue and urea were excluded as adhesives in one example due to poor adhesion. EPI adhesives achieve good adhesion in one example.

In one example, PUR adhesives achieve very good adhesion.

In addition, the stabilization layer should be matched to the overall structure. The following example structure:

- Oak (wear layer), 0.9 mm thick, preferred lengthways;

- Glass fiber with EPI adhesive (stabilization layer), 0.3 mm thick, preferred direction transverse or not available;

- Birch (first base layer), 1.5 mm thick, preferred direction across;

- PVAc adhesive layer (bonding layer);

- Birch (second base layer), 1.0 mm thick, preferred lengthways; is a complex asymmetrical system with a wide range of swelling and shrinkage dimensions and thicknesses, which harmonize efficiently and robustly in the overall network.

FIG. 1 shows a cross section through an underground laying unit 100 according to an exemplary embodiment of the invention. The underground laying unit 100 is designed as a floor panel, which has two long sides 101 and two wide sides 102, which are referred to as front sides. It is noticeable that none of these end faces 101, 102 have connecting elements, which are conventionally always present and used to connect a floor panel to another floor panel at the end faces. Such connectors typically include, for example, snap-in or click-in connectors.

The underground installation unit 100 shown has five layers (between which thin layers of adhesive can be arranged), which are arranged in the following order: i) a wear layer 110, which has a wood veneer, which is a layer of real wood or solid wood , e.g. oak. The wood veneer is anisotropic due to the wood fibers and therefore has a first preferred direction RI. Furthermore, the wood veneer shows a pronounced swelling and shrinking behavior when there is a change in humidity (change between a dry climate and a humid climate). ii) a stabilization layer 120, which comprises a material which, in contrast to a wood veneer layer, does not show any swelling and shrinking behavior with a change in humidity. In principle, the stabilizing layer has no wood. In one example, the stabilization layer 120 is designed as a fiber layer embedded in a synthetic resin matrix, which is reinforced by means of fibers (eg glass fibers). However, other advantageous configurations are also possible, for example as a viscose mat. The stabilization layer preferably has anisotropy, in particular, for example, when fibers are used. This can result in a fourth preferred direction R4, which is coordinated with the first preferred direction RI. The material preferably has a high modulus of elasticity compared to that of the wear layer 110 . iii) a first support layer 130, which has an anisotropic material and thus a second preferred direction R2. iv) a second base layer 140, which is also an anisotropic material and thus has a third preferred direction R3.

The base layers 130, 140 can have the same material or different materials. In one example, the base layers are made of wood veneer, e.g. birch. In further examples, the base layers 130, 140 can also have plastic or metal.

The preferred directions R1, R2, R3 and R4 are matched to one another in such a way that the underground laying unit 100 is self-stabilized with regard to the swelling and shrinkage behavior in the event of changes in humidity (dry climate and humid climate). This also applies to cupping (curving of the panel concave/convex).

In the example shown, the first preferred direction RI and the third preferred direction R3 are arranged parallel to one another and the second preferred direction R2 is arranged perpendicular to the first preferred direction RI and the third preferred direction R3. In a preferred example, the fourth preferred direction R4 is transverse to the first preferred direction RI, but does not form a counteracting layer to the wear layer. v) a connection structure 150, which is designed as a connection layer and makes it possible to provide a detachable connection to the substrate 200. In the example shown, the connection structure 150 is set up to be detachably connected to an underground connection structure 160 on an underground floor 201 . The underground laying unit 100 has a thickness of 4.2 mm, for example, with the connecting structure 150 having a thickness of 1 mm, for example. The wear layer 110 has a thickness in the range of 0.4 mm to 0.9 mm, depending on the wood veneer used.

A subsurface 200 having the subsurface connection layer 160 is shown under the subsurface laying unit 100 . This serves as a sub-floor covering for the actual sub-floor 201, e.g. a screed. In the example shown, the subsurface connecting layer 160 is designed as a magnetic foil that is laid (unrolled) floating on the subsurface 201 . If the connecting structure 150 and the subsurface connecting structure 160 are coupled magnetically, the subsurface laying unit 100 is laid on the subsurface 200 in a floating manner or without adhesive.

If a plurality of underground laying units 100, as described above, are used to cover the underground 200, they are all laid in a floating manner and free of end connection elements. The result of this is that at least some of the laid underground laying units 100 can be moved in the vertical direction and thus enable a completely new feeling of walking and can also be replaced particularly easily at a later date.

FIG. 2 shows a cross-sectional view of an underground laying unit 100 according to a further exemplary embodiment of the invention. The structure is very similar to that of FIG. In addition, a connecting layer 135 is provided, which is arranged between the first base layer 130 and the second base layer 140 . The tie layer 135 includes an adhesive and can be targeted to provide certain desired properties.

FIG. 3 clearly shows the swelling and shrinking behavior of an underground laying unit 100 according to an exemplary embodiment of the invention in a humid climate and in a dry climate. While there is a concave curvature of around 0.04 mm in a humid climate, a convex curvature of around 0.04 mm can be observed in a dry climate.

FIG. 4 clearly shows the overall path of the swelling and shrinking behavior of the underground laying unit according to an exemplary embodiment of the invention in a humid and dry climate. The bulges described in FIG. 3 result in a total travel of 0.08 mm. This is a particularly advantageous and very small overall distance, which is even smaller than in the case of a large number of multi-layer parquet floors glued over the entire surface.

In addition, it should be pointed out that "having" does not exclude any other elements or steps and "a" or "a" does not exclude a plurality. It should also be pointed out that features or steps that have been described with reference to one of the above exemplary embodiments, also may be used in combination with other features or steps of other embodiments described above Reference signs in the claims are not to be regarded as limiting.

Reference sign

100 underground laying unit

101 end face lengthways

102 end face across 110 wear layer

120 stabilization layer

130 First base course

135 tie layer

140 Second base course

150 connection structure

160 underground connection structure

200 underground

201 Subsoil R preferred direction

Claims

Expectations

1. An underground installation unit (100), in particular a floor panel or a wall panel, for floating installation on an underground (200), wherein the underground installation unit (100) has: a wear layer (110) which has a wood veneer, the wear layer having a first preferred direction (RI); a stabilizing layer (120) comprising a material which exhibits essentially no swelling and shrinking behavior with a change in humidity; a first base layer (130) which has a second preferred direction (R2); a second base layer (140) which has a third preferred direction (R3); and a connection structure (150) configured to provide a releasable connection to the substrate (200); wherein the preferred directions (RI, R2, R3) are coordinated with one another in such a way that the underground laying unit (100) is essentially self-stabilizing with regard to the swelling and shrinkage behavior in the event of changes in humidity.

2. The underground laying unit (100) according to claim 1, wherein the underground laying unit (100) is free of connecting elements to further underground laying units (100) on all end faces (101, 102).

3. The underground laying unit (100) according to claim 1 or 2, wherein the connection structure (150) comprises at least one from the group consisting of: a magnetic layer, a magnetic foil, a magnetic mat, a plurality of magnetic elements, a snap connection, a Plug-in connection, a tongue and groove connection, a Velcro mat, a removable adhesive layer, an electrostatically charged mat, a slip mat, a nanomat, a spray or brush layer, an arrangement of suction cups.

4. The underground laying unit (100) according to any one of the preceding claims, wherein the underground laying unit (100) has a thickness of 4.8 mm or less, in particular 4.2 mm or less.

The underground laying unit (100) according to any one of the preceding claims, wherein the connection structure (150) has a thickness of 1.5 mm or less, in particular 1 mm or less; and/or wherein the wear layer (110) has a thickness in the range from 0.2 to 1.1 mm, in particular in the range from 0.4 mm to 0.9 mm.

The underground laying unit (100) according to any one of the preceding claims, wherein the first base layer (130) and/or the second base layer (140) comprises a further wood veneer, in particular wherein at least one wood veneer comprises a real wood layer.

The underground laying unit (100) according to any one of the preceding claims, wherein the first preferential direction (RI) and the third preferential direction (R3) are arranged substantially parallel to one another; and/or wherein the second preferred direction (R2) is arranged substantially perpendicular to the first preferred direction (RI) and the third preferred direction (R3).

The underground laying unit (100) according to any one of the preceding claims, wherein the stabilization layer (150) has a fourth preferred direction (R4), in particular wherein the fourth preferred direction (R4) is arranged substantially perpendicular to the first preferred direction (RI).

9. The underground laying unit (100) according to any one of the preceding claims, wherein the stabilization layer (150) comprises at least one from the group consisting of: a resin matrix, a fiber material, a fiber-reinforced plastic, a viscose matrix, a Metal foil, in particular an aluminum foil, a mineral bonded fiber board, a material with a high modulus of elasticity compared to the wear layer (110), an anisotropic material.

The underground installation unit (100) according to any one of the preceding claims, further comprising: a tie layer (135) disposed between the first support layer (130) and the second support layer (140), in particular wherein the tie layer (135) comprises an adhesive and/or has a natural resin.

11. An underground covering, in particular a floor covering or a wall covering, comprising: a plurality of underground laying units (100) according to any one of claims 1 to 10, wherein the plurality of underground laying units (100) are floating and free of end connection elements on the underground (200) are misplaced.

12. The subsurface according to claim 11, wherein at least one of the laid subsurface laying units (100) is at least partially movable in the vertical direction.

13. The subsurface according to claim 11 or 12, further comprising: a subsurface connection structure (160) which is on a

Underground floor (201) is laid, and which is detachably connected to the connecting structure (150).

The subsurface according to claim 13, wherein the connecting structure (150) comprises a magnetic layer, and wherein the subsurface connecting structure (160) comprises another magnetic layer floating on the subfloor (201).

15. A method for laying underground laying units (100), the method comprising: providing a plurality of underground laying units (100) according to any one of claims 1 to 10;

providing an underground connection structure (160) on an underground floor (201);

laying the plurality of underground laying units (100) such that the connecting structures (150) are detachably coupled to the underground connecting structure (160);

releasing the coupling between at least one of the connecting structures (150) and the underground connecting structure (160) to remove at least one of the underground laying units (100); and

Replacing the at least one underground laying unit (100) with another underground laying unit (100).