EP4060141B1 - Self-stabilized base laying unit and base covering - Google Patents

Description

Technical field of the invention

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

The present invention can therefore relate to the technical field of subsurface 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 complex to install. In addition, wood as a material reacts strongly to changes in moisture (literally "wood works") and therefore shows 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 each other 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 subsurface, in particular a subsurface laying unit, wherein the surface laying unit has a wear layer and a connecting structure attached directly to an underside of the wear layer, which is set up to connect to the subsurface.

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

However, laying and replacing a parquet panel requires compliance WO 2012/156192 or EP 3 070 231 A1 still requires quite a lot of effort, because it is absolutely necessary to provide complex subsurface laying units on which the surface laying units can then be attached. This is particularly due to the fact that the surface laying units as such are exposed to high (intrinsic) stresses and are therefore not self-stabilized. WO 2018/237096 A1 describes a modular and magnetic wooden panel with several layers.

Summary of the invention

It is an object of the present invention to enable laying of subsurface laying units on a subsurface in a resource-saving, environmentally friendly, flexible, low-effort and at the same time reliable and protected against undesirable high (intrinsic) stresses.

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

1. i) eine Nutzschicht, welche ein Holzfurnier (insbesondere ein Echtholzfurnier) aufweist, wobei die Nutzschicht eine (erste Anisotropie-Eigenschaft und somit eine) erste Vorzugsrichtung aufweist;
2. ii) eine Stabilisierungsschicht (z.B. eine Glasfasermatte), welche ein Material aufweist, das (im Wesentlichen) kein Quell- und Schwindverhalten bei einer Feuchtigkeitsveränderung zeigt (also z.B. kein Holzfurnier);
3. iii) eine erste Tragschicht (z.B. ein weiteres Holzfurnier), welche eine (zweite Anisotropie-Eigenschaft und somit eine) zweite Vorzugsrichtung aufweist;
4. iv) eine zweite Tragschicht (z.B. ein weiteres Holzfurnier), welche eine (dritte Anisotropie-Eigenschaft und somit eine) dritte Vorzugsrichtung aufweist; und
5. v) eine Verbindungsstruktur (z.B. eine Magnetfolie, ein mechanischer Einrastmechanismus, etc.), welche konfiguriert ist eine lösbare Verbindung mit dem Untergrund bereitzustellen.

Hierbei sind die Vorzugsrichtungen derart aufeinander abgestimmt, dass die Untergrundverlegeeinheit bei Feuchtigkeitsveränderungen bezüglich des Quell- und Schwindverhaltens (im Wesentlichen) selbststabilisiert ist.According to one aspect of the present invention, a subsurface laying unit (in particular a floor panel or a wall panel or a ceiling panel) is described for floating (e.g. adhesive-free) laying on a subsurface (e.g. on a subsurface connecting structure, directly on a screed, etc.), wherein the Underground laying unit has:

1. 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;
2. ii) a stabilization layer (e.g. a glass fiber mat) which has a material that (essentially) shows no swelling and shrinkage behavior when the humidity changes (e.g. not a wood veneer);
3. iii) a first base layer (eg another wood veneer) which has a (second anisotropy property and thus a) second preferred direction;
4. iv) a second base layer (eg another wood veneer) which has a (third anisotropy property and thus a) third preferred direction; and
5. v) a connection structure (e.g. a magnetic foil, a mechanical latching mechanism, etc.) which is configured to provide a releasable connection to the substrate.

Here, the preferred directions are coordinated with one another in such a way that the subsurface laying unit is (essentially) self-stabilized in the event of changes in moisture with regard to swelling and shrinkage behavior.

According to a further aspect of the present invention, a subsurface covering is described, which comprises: a plurality of subsurface laying units as described above. Here, the subsurface laying units of the majority of subsurface laying units are laid on the subsurface floating and free of frontal connecting elements (thus the subsurface laying units are not connected to one another by additional connecting elements).

1. i) Bereitstellen einer Mehrzahl von Untergrundverlegeeinheiten wie oben beschrieben;
2. ii) Bereitstellen einer Untergrund-Verbindungsstruktur (z.B. einem Gegenstück zu der Verbindungsstruktur) auf dem Untergrundboden (z.B. einem Estrich);
3. iii) Verlegen der Mehrzahl von Untergrundverlegeeinheiten (frei von Verbindungselementen untereinander) derart, dass die Verbindungsstrukturen (der Untergrundverlegeeinheiten) mit der Untergrund-Verbindungsstruktur (bzw. einer Mehrzahl von Untergrund-Verbindungsstrukturen) lösbar gekoppelt werden (und dadurch Bereitstellen eines Untergrundbelags wie oben beschrieben);
4. iv) Lösen der Kopplung zwischen mindestens einer der Verbindungsstrukturen und der Untergrund-Verbindungsstruktur (bzw. der Mehrzahl von Untergrund-Verbindungsstrukturen) zum Entfernen von zumindest einer der Untergrundverlegeeinheiten; und
5. v) Ersetzen von der zumindest einen Untergrundverlegeeinheit (welche z.B. schon abgenutzt ist) durch eine weitere Untergrundverlegeeinheit (welche z.B. noch nicht abgenutzt ist).

According to a further aspect of the present invention, a method for laying underground laying units is described, the method comprising:

1. i) providing a plurality of subsurface laying units as described above;
2. ii) providing a subsurface connection structure (e.g. a counterpart to the connection structure) on the subsurface floor (e.g. a screed);
3. iii) laying the plurality of subsurface laying units (free of connecting elements between each other) in such a way that the connecting structures (of the subsurface laying units) are releasably coupled to the subsurface connecting structure (or a plurality of subsurface connecting structures) (and thereby providing a subsurface covering as described above) ;
4. iv) releasing the coupling between at least one of the connection structures and the underground connection structure (or the plurality of underground connection structures) to remove at least one of the underground laying units; and
5. v) Replacing the at least one subsurface laying unit (which, for example, is already worn out) with another subsurface laying unit (which, for example, is not yet worn out).

In the context of this description, a “subsurface laying unit” can be understood to mean in particular a multi-layer module (in particular a multi-layer parquet module), the wear layer of which is on or laid over a substrate is exposed or visible to the outside (if necessary still covered with an optional protective coating). The laying of the underground laying unit can be carried out, for example, by means of the connecting structure on the underside of the underground laying unit with a substrate. The term underground laying unit is to be understood as meaning that it can be installed 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 subsurface laying units can be manufactured in virtually any format. This includes in particular every square configuration, and in particular rectangular arrangements (panels). But other shapes, such as polygons, are also possible.

In the context of this description, “parquet” can be understood as a subsurface covering for rooms that has wood. The wood, usually hardwood from trees, can be sawn into small pieces and put together according to specific patterns. A distinction must be made from parquet as a 'laminate flooring', because laminate floorings consist of wood fiber materials as a carrier and are coated with melamine resin, whereby the visible wooden surface here 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 to mean, in particular, a layer close to the surface or a surface layer or a board on which the actual mechanical and/or chemical stress on the installed floor or wall covering takes place. In a parquet floor, a wear layer can be that which a user uses as a floor to walk on. For the purposes of this description, a wear layer may be a "board-like rigid layer" which has the mechanical properties of a board. For example, such a layer cannot be wound on a roll. According to one embodiment, the wear 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. For example, it can be made of solid wood.

European types of wood that are processed into layers of the subsurface installation unit (in particular the wear layer or base layers). Examples include oak, beech, maple, birch, walnut, cherry, ash, olive, acacia, elm, apple tree, pear tree, larch, pine and sweet chestnut. Non-European types of wood that can be used include merbau, wenge, teak or mahogany.

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

In this description, the term “swelling and shrinkage behavior (or amount of swelling and shrinkage)” can refer in particular to the fact that the volume of wood increases or decreases when the humidity changes. Simply put, wood can expand or shrink. Swelling and shrinkage can be parameters for the hygroscopic properties of wood and wood-based materials, which describe the dimensional change of a workpiece depending on the wood moisture. The amount of shrinkage refers to the change caused by the reduction in the moisture contained (shrinkage), while the amount of swelling refers to the change caused by the absorption of moisture (swelling).

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

1. 1. Das Quell- und Schwindverhalten ist bezogen auf einen bestimmten Holzfeuchtebereich, da der Verlauf nicht linear ist.
2. 2. Bei allgemeinen Werten wie der 1:10:20 Faustregel (grober Richtwert über alle Holzarten und Feuchtigkeiten hinweg) spricht man üblicherweise von dem Bereich 0% - FSB (Fasersättigungsbereich, von der Holzart abhängig, liegt in etwa bei 25 - 30%).
3. 3. Erstellen einer Holzprobe mit definierter Dimension und entsprechender Faserausrichtung, Bringen dieser auf die gewünschte Holzfeuchte, Kontrollieren dieser durch die Darrmethode, Vermessen der Probe, und Setzen der gemessenen Dimensionen in Relation.

In principle this can be done as follows:

1. 1. The swelling and shrinkage behavior is related to a specific wood moisture range, as the progression is not linear.
2. 2. For general values such as the 1:10:20 rule of thumb (rough guideline across all types of wood and moisture content), one usually speaks of the range 0% - FSB (fiber saturation range, depending on the type of wood, is approximately 25 - 30%) .
3. 3. Creating a wood sample with defined dimensions and corresponding fiber orientation, bringing it to the desired wood moisture content, checking it using the kilning method, measuring the sample, and putting the measured dimensions in relation.

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

In conjunction with the swelling and shrinking behavior, wooden panels when installed can also bulge outwards (convex) or inwards (concave) when the humidity changes (so-called cupping), see Figures 3 and 4 below.

In the context of this description, a “stabilization layer” can be understood to mean, in particular, a layer or a board that is remote from the surface and serves to ensure the stability of the installed floor or wall covering as a whole. Preferably, the stabilizing layer does not exhibit any swelling or shrinkage behavior when there are changes in humidity, unlike e.g. wood veneer. In one example, the stabilization layer has (substantially) 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 or shrinkage behavior when there are changes in humidity. In one example, the stabilization layer has an anisotropic property and a corresponding preferred direction. This is the case, for example, if the stabilization layer has fibers, e.g. a glass fiber-reinforced plastic mat. However, the stabilization layer can also have an isotropic material, for example in the form of aluminum foil.

In the context of this description, a “base layer” can be understood to mean in particular a layer or a board that is remote from the surface and that increases the stability of the subsurface laying unit. A base layer can function as a barrier layer and/or as a counteracting layer. In one example, the base layer has a wood veneer, but other configurations are also possible, for example plastic or metal. However, this should be implemented in such a way that a preferred direction is present in order to act as a barrier layer and/or as a counter-traction layer in conjunction with the useful view.

In the context of this description, a “connecting structure” can be understood in particular to mean any physical structure that is specifically adapted to form a connection with the intended adjacent element (e.g. a subsurface connection structure or a counterpart), i.e. to exert a fastening force on it. A connection structure can be designed as a layer or as one or more specially placed elements. The subsurface laying unit can be laid, for example, by means of an additional connection structure on the underside of the subsurface connection structure and/or by means of an additional connection structure on the top of the subsurface. It is also possible to lay the subsurface connecting structure on the subsurface in a floating manner (e.g. with a magnetic film).

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

In the context of this description, a “top side” of a layer or an element can be understood to mean, in particular, a main surface of this layer or this element, which faces away from the subsurface when this layer or this element is laid as intended. Accordingly, a “bottom side” of a layer or an element can be understood to mean, in particular, a main surface of this layer or this element which faces the subsurface 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 a subsurface installation unit is laid on a subsurface in a reversible manner, i.e. in a non-destructive manner. A Such reversible laying can be achieved, for example, using magnetic elements, snap-in elements or no connection at all. Connecting using a special, easily removable adhesive (e.g. residue-free) is also conceivable. However, the term “floating installation” does not include conventional adhesives (e.g. silane-modified parquet adhesive (SMP) or PUR adhesive), which do not allow the subsurface installation unit to be removed without leaving any residue.

In the context of this description, a “detachable connection” of two elements by means of a connection structure can be understood in particular to mean that after such a connection has been formed, it can be reversibly and non-destructively detached again by applying a release force. Through such a non-destructive release, the connection structure can be reused after release, in particular reused at least ten or at least a hundred times, without the connection function suffering or being impaired. Disconnecting such a connection can be carried out by a user without using a tool.

In one embodiment, applying a release force of less than 200 N, in particular of less than 100 N, more particularly of less than 50 N may be sufficient for such a release. In order to avoid unwanted loosening of the laid covering, the loosening force should be at least 10 N, in particular more than 20 N, and in particular more than 30 N. However, the forces can also have other sizes.

According to an exemplary embodiment, the invention can be based on the idea that laying underground laying units on a substrate is possible in a resource-saving, environmentally friendly, flexible, low-effort and at the same time reliable and protected against undesirable high (intrinsic) stresses if a self-stabilized underground laying unit is included a very special layer structure is used.

For this purpose, a barrier structure is chosen 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 tensions caused by the swelling and shrinkage behavior when the moisture changes are blocked. A stabilization layer is now installed under the wear layer and above the base layers, which does not exhibit any swelling or shrinkage behavior This enables optimal self-stabilization of the subsurface laying unit.

Conventionally, damage caused by changes in moisture is counteracted by firmly (inextricably) gluing thick parquet panels to the substrate and interlocking them 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 subsurface laying unit (which still has a stable wooden wear layer) can be laid floating in a simple, cost-effective and flexible manner (without connecting elements), but this subsurface laying unit is self-stabilizing (and thus free of internal stresses) compared to the swelling and shrinkage behavior and curvatures in the event of changes in humidity (see, for example, the particularly small curvatures in the 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. This makes the latter superfluous and enables simple, resource-saving replacement of subsurface laying units.

Exemplary embodiments

According to one exemplary embodiment, the subsurface laying unit is free of connecting elements to further subsurface laying units on all end faces (longitudinal sides and width sides). This can have the advantage that material and manufacturing costs can be saved while still providing the necessary stability. In particular, this new method of laying can advantageously create a completely different feeling when walking, for example because subsurface laying units are vertically movable.

Conventionally, subsurface installation units such as parquet panels are provided on the front sides with connecting elements to other subsurface installation units in order to provide a robust connection and thus a stable subsurface covering. These connecting elements usually include click-in or snap-in mechanisms based on the tongue and groove principle. However, connecting elements are usually made from wood or wood scraps These can also have metal or plastic, for example. To attach it, it is necessary to click or snap into place, usually on all front sides. In the case of a floor panel there are two long sides and two width sides. But other shapes with more front sides are also conceivable. These connecting elements (in a simple or very complex structure) are so widespread that a stable panel structure without them does not seem possible.

However, the inventors have now surprisingly realized that such a structure without connecting elements is made possible in a stable and robust manner by using the self-stabilized subsurface laying unit described.

According to a further exemplary embodiment, the connection structure has at least one from the group which consists 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-in connection, a click-in connection connection, a plug-in connection, a tongue-and-groove connection, a Velcro mat, a removable adhesive layer (e.g. double-sided adhesive tape), an electrostatically charged mat (whereby the charge carriers can be enclosed inside such a mat), a non-slip mat (for example made of a Rubber material with high static friction), a spray or brush layer and / or an arrangement of suction cups can be formed.

This can have the advantage of allowing a variety of different connection options depending on the existing conditions. Magnetic, mechanical, electrical forces or a combination thereof can be used to realize the detachable or reversible connection characteristics between the subsurface laying unit and the subsurface (connecting structure). It can therefore 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 base layer, in particular sprayed on as a dryable spray fluid, applied as a dryable coating 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 chips) and a solvent, etc. can be applied. After the suspension has dried, a thin and cost-effective magnetic layer remains on the wear layer. The connection structure may also include a hot melt adhesive. A hot melt adhesive is applied in molten form and then adheres to the surface when cooled to a temperature below the melting point.

According to a further exemplary embodiment, the subsurface 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 fewer. This means that material can be saved and the subsurface laying unit can be laid particularly flexibly without the floor structure height becoming too high.

Compared to known floor panels, this installation height (with at least five existing layers including a wood veneer wear layer) is extremely low. It is extremely surprising that such a thin multi-layer panel is still stable enough to withstand the stresses that a subsurface is exposed to in daily use.

According to a further exemplary embodiment, the connecting 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 0.2 to 1.1 mm, in particular in the range 0.4 mm to 0.9 mm.

This also allows material to be saved and the subsurface laying unit can be laid particularly flexibly without the floor structure height becoming too high. Compared to known floor panels, these thicknesses are very small and it is surprising that the desired functions of tread stability or ground connection stability are still possible efficiently and robustly despite the small thickness.

According to a further exemplary embodiment, the first base layer and/or the second base layer has a further 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 straight away. In the case of the wear layer can A layer of real wood gives a particularly positive visual impression in addition to the stability advantages (and ease of care). A wood veneer layer can have a particularly stabilizing effect on the base layers.

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

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 (essentially) perpendicular to the first preferred direction and the third preferred direction. This can result in an advantageous barrier effect, which works efficiently for self-stabilization, even in the event of strong fluctuations in humidity and/or temperature. The thicknesses of the wear layer and the base layers as well as their materials can be coordinated with one another in such a way that the desired barrier 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 have the advantage that a further barrier effect or self-stabilization can be individually/flexibly introduced directly below the wear layer.

According to a further exemplary embodiment, the stabilizing layer has at least one from the group which consists of: a resin matrix (e.g. PUR, EPI, etc.), a fiber material, a fiber-reinforced plastic, a viscose matrix, a metal foil, in particular aluminum Film, a mineral-bonded fiberboard, a material with a high modulus of elasticity compared to the wear layer, an anisotropic material. There are therefore a number of options for choosing the stabilization layer in such a way that the desired properties can be obtained.

When it comes to plywood, the anisotropy (different properties in different directions of the coordinate system) is usually taken into account Wood is used and prevents distortion. According to an exemplary embodiment of the invention, this effect is reinforced by a glass fiber mat that is also anisotropic and precisely tailored to the warping properties of the wood. The tensile fiber is therefore not used in the classic way as a "counter-tension" (with 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 transverse layer of plywood).

The stabilization layer can be tailored to the warping properties of wood veneer (e.g. hardwood sliced veneer) using different grammages in the longitudinal and transverse directions in order to reduce 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 variety of customization and optimization options.

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

According to one embodiment, the stabilization layer can directly adjoin the wear 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 approximately 10:13. Here the preferred direction can be aligned transversely to the grain direction of a wood veneer layer (e.g. oak). However, a fiber optic with a uniform distribution, i.e. 1:1, can also be used. However, this would still be anisotropic because it has no fibers in its thickness. In an exemplary embodiment, the barrier effect of the glass fiber also applies to the wear layer (e.g. oak) and the underlying base layer (e.g. birch). For this reason, the fiber optic can now have almost equal orientation between longitudinal and transverse.

According to a further exemplary embodiment, the subsurface laying unit further comprises: 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, a robust fastening of the Base layers can be carried out next to each other. The connecting 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 walking experience can be provided, although material and manufacturing costs are saved.

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

According to a further exemplary embodiment of the subsurface covering, the connecting structure has a magnetic layer, and the subsurface connecting structure has a further magnetic layer which is laid floating on the subsurface. This describes a particularly advantageous structure in which the underground connecting structure can also be installed floating (figuratively: simply roll out the magnetic film). This results in a structure that is as thin as possible while at the same time saving material and manufacturing costs.

According to a further exemplary embodiment, the total path of the swelling and shrinkage behavior or the curvature of the subsurface laying unit when changing between a wet 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.

Short description of the characters

• Figur 1 zeigt eine Querschnittansicht einer Untergrundverlegeeinheit und eines Untergrundes gemäß einem exemplarischen Ausführungsbeispiel der Erfindung.
• Figur 2 zeigt eine Querschnittansicht einer Untergrundverlegeeinheit gemäß einem weiteren exemplarischen Ausführungsbeispiel der Erfindung.
• Figur 3 zeigt anschaulich das Quell- und Schwindverhalten einer Untergrundverlegeeinheit gemäß einem exemplarischen Ausführungsbeispiel der Erfindung bei Feuchtklima und Trockenklima (Feuchtigkeitsveränderung).
• Figur 4 zeigt anschaulich den Gesamtweg des Quell- und Schwindverhaltens der Untergrundverlegeeinheit gemäß einem exemplarischen Ausführungsbeispiel der Erfindung bei Feuchtklima und Trockenklima (Feuchtigkeitsveränderung).

Exemplary embodiments of the present invention are described in detail below with reference to the following figures.

• Figure 1 shows a cross-sectional view of a subsurface laying unit and a subsurface according to an exemplary embodiment of the invention.
• Figure 2 shows a cross-sectional view of a subsurface laying unit according to a further exemplary embodiment of the invention.
• Figure 3 clearly shows the swelling and shrinkage behavior of a subsurface laying unit according to an exemplary embodiment of the invention in wet climates and dry climates (change in humidity).
• Figure 4 clearly shows the overall path of the swelling and shrinkage behavior of the subsurface laying unit according to an exemplary embodiment of the invention in wet climates and dry climates (change in humidity).

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

Detailed description of exemplary embodiments

1. 1) Echtholznutzschicht (Holzfurnier) mit Dicke im Bereich 0,4 mm bis 0,9 mm (minus eventuell Bürstung).
   Funktion: Optisch ansprechende Oberfläche, Trägerschicht für die Oberflächenbeschichtung, Widerstand gegen Stoß und Druckbelastungen.
2. 2) Stabilisierungsschicht: Glasfaser Roving-Gewebe, hinsichtlich Grammatur und Fadenstärke auf das Verzugsverhalten der Echtholznutzschicht abgestimmt, eingebunden in eine Matrix aus Kunstharz (EPI oder PUR).
3. 3) Erste Tragschicht: quer zur Echtholznutzschicht ausgerichtete Echtholzfurnierlage (Birke-Schälfurnier 1,5 mm oder Eiche-Messerfurnier 0,9 mm).
4. 4) Verbindschicht: Klebstoff, z.B. eines von PUR, EPI, PVAC.
5. 5) Zweite Tragschicht (Gegenzugsfurnier): längs/parallel zur Echtholznutzschicht ausgerichtete Echtholzfurnierlage (Birke-Schälfurnier 1,0 mm oder Eiche-Messerfurnier 0,9 mm).

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

1. 1) Real wood wear layer (wood veneer) with a thickness in the range 0.4 mm to 0.9 mm (minus possibly brushing).
   Function: Visually appealing surface, carrier layer for the surface coating, resistance to impact and pressure loads.
2. 2) Stabilization layer: Glass fiber roving fabric, tailored to the warping behavior of the real wood wear layer in terms of grammage and thread thickness, integrated into a matrix made of synthetic resin (EPI or PUR).
3. 3) First base layer: real wood veneer layer aligned transversely to the real wood wear layer (birch peeled veneer 1.5 mm or oak sliced veneer 0.9 mm).
4. 4) Bonding layer: Adhesive, e.g. one of PUR, EPI, PVAC.
5. 5) Second base layer (counter-pulling veneer): real wood veneer layer aligned lengthways/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 chosen, which for the first time enables a (real wood) Subfloor covering with a total thickness of < 3 mm can be laid in a "floating" manner without frontal connecting elements (longitudinal and transverse) with a comparable swelling and shrinkage behavior (in the event of 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 to "shut off" the swelling and shrinkage behavior of the wear layer, although the stabilization layer does not act as a counterweight.

According to an exemplary embodiment of the invention, the properties of different types of wood and those of 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 bowl ( in addition to blocking the swelling and shrinking behavior).

According to an exemplary embodiment of the invention, a variable introduction of water through different water contents in the glue joints, as achieved, for example, by adding water or different adhesive systems (EPI/PVAc/PUR), can be used to advantage. This inhomogeneous introduction of water initiates tensions in the multi-layer structure during the pressing process, which means that the initial distortion (slight pre-stress in the convex direction) can be provided as desired.

• Grammatur: Wie viele g/m² Glasfasermaterial in die jeweilige Richtung (längs/quer) verarbeitet werden. Hohe Grammaturen bewirken eine höhere Steifigkeit, sofern alle Fasern gut in den Klebstoff eingebettet sind.
• Fadenstärke: Dicke der Fäden angegeben in tex. Dünnere Fäden (z.B. im Bereich 110 bis 150 tex, insbesondere 130 bis 140 tex, bei etwa 100 g/m²) bei gleichbleibender Grammatur ermöglichen eine bessere Leimdurchdringung. Dünnere Fäden erzeugen eine bessere Leimdurchdringung und Bindung und kompensieren somit die geringere Grammatur. Dickere Fäden erhöhen die Unebenheit und reduzieren die Bindung von Glasfaser zu Holz.
• Eine offenere Struktur ermöglicht eine bessere Leimdurchdringung, erhöht aber die Unebenheit.
• Nachbearbeitung ("Brennen") der Glasfaser reduziert die "Verschmutzungen" und erhöht die Leimhaftung an der Faser.
• Klebstoffe: Weißleim und Harnstoff wurden aufgrund geringer Haftung in einem Beispiel als Klebstoff ausgeschlossen. EPI Klebstoffe erreichen in einem Beispiel gute Haftungen.

PUR Klebstoffe erreichen in einem Beispiel sehr gute Haftungen.According to an exemplary embodiment of the invention, possible adjustment screws when providing the stabilization layer are:

• Grammage: How many g/m ² of fiberglass material are processed in the respective direction (longitudinal/crosswise). High grammages result in greater rigidity as long as all fibers are well embedded in the adhesive.
• Thread thickness: Thickness of the threads given in tex. Thinner threads (eg in the range 110 to 150 tex, especially 130 to 140 tex, at about 100 g/m ² ) with the same grammage enable better glue penetration. Thinner threads produce better glue penetration and binding and thus compensate for the lower grammage. Thicker threads increase unevenness and reduce the bonding of fiberglass to wood.
• A more open structure allows for better glue penetration but increases unevenness.
• Post-processing (“burning”) the fiberglass reduces “contamination” and increases glue adhesion to the fiber.
• Adhesives: White glue and urea were excluded as adhesives in one example due to poor adhesion. In one example, EPI adhesives achieve good adhesion.

In one example, PUR adhesives achieve very good adhesion.

• Eiche (Nutzschicht), 0,9 mm Dicke, Vorzugsrichtung längs;
• Glasfaser mit EPI Klebstoff (Stabilisierungsschicht), 0,3 mm Dicke, Vorzugsrichtung quer oder nicht vorhanden;
• Birke (erste Tragschicht), 1,5 mm Dicke, Vorzugsrichtung quer;
• PVAc Klebstoffschicht (Verbindschicht);
• Birke (zweite Tragschicht), 1,0 mm Dicke, Vorzugsrichtung längs;

ist ein komplexes asymmetrisches System mit unterschiedlichsten Quell- und Schwindmaßen und Dicken, welche aber im Gesamtverbund effizient und robust harmonieren.In addition, the stabilization layer should be tailored to the overall structure. The following example structure:

• Oak (wear layer), 0.9 mm thick, preferred direction lengthwise;
• Glass fiber with EPI adhesive (stabilizing layer), 0.3 mm thick, preferred direction transverse or not available;
• Birch (first base layer), 1.5 mm thick, preferred direction transverse;
• PVAc adhesive layer (connecting layer);
• Birch (second base layer), 1.0 mm thick, preferred direction lengthwise;

is a complex asymmetrical system with a wide variety of swelling and shrinkage dimensions and thicknesses, but which harmonize efficiently and robustly as a whole.

Figure 1 shows a cross section through a subsurface 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 width sides 102, which are referred to as end faces. 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 on the end faces. Such connecting elements usually include, for example, snap-in or click-in connections based on the tongue-and-groove principle.

1. i) eine Nutzschicht 110, welche ein Holzfurnier aufweist, bei dem es sich um eine Echtholz-Schicht bzw. ein Vollholz, z.B. Eiche, handelt. Das Holzfurnier ist durch die Holzfasern anisotrop und weist daher eine erste Vorzugsrichtung R1 auf. Weiterhin zeigt das Holzfurnier bei einer Feuchtigkeitsveränderung (Wechsel zwischen Trockenklima und Feuchtklima) ein ausgeprägtes Quell- und Schwindverhalten.
2. ii) eine Stabilisierungsschicht 120, welche ein Material aufweist, das im Gegensatz zu einer Holzfurnierschicht kein Quell- und Schwindverhalten bei einer Feuchtigkeitsveränderung zeigt. Im Prinzip weist die Stabilisierungsschicht kein Holz auf. In einem Beispiel ist die Stabilisierungsschicht 120 als in eine Kunstharzmatrix eingebundene Faserlage ausgebildet, welche mittels Fasern (z.B. Glasfaser) verstärkt ist. Es sind aber auch weitere vorteilhafte Ausgestaltungen möglich, z.B. als eine Viskosematte. Die Stabilisierungsschicht weist bevorzugt eine Anisotropie auf, insbesondere z.B. bei einem Einsatz von Fasern. Dadurch kann sich eine vierte Vorzugsrichtung R4 ergeben, welche mit der ersten Vorzugsrichtung R1 abgestimmt wird. Das Material weist bevorzugt einen hohen Elastizitätsmodul im Vergleich mit dem der Nutzschicht 110 auf.
3. iii) eine erste Tragschicht 130, welche ein anisotropes Material und somit eine zweite Vorzugsrichtung R2 aufweist.
4. iv) eine zweite Tragschicht 140, welche ebenfalls ein anisotropes Material und somit eine dritte Vorzugsrichtung R3 aufweist.

Die Tragschichten 130, 140 können dasselbe Material oder verschiedene Materialien aufweisen. In einem Beispiel sind die Tragschichten aus Holzfurnier vorgesehen, z.B. aus Birke. In weiteren Beispielen können die Tragschichten 130, 140 aber auch Kunststoff oder Metall aufweisen.The subsurface laying unit 100 shown has five layers (between which thin adhesive layers can be arranged), which are arranged in the following order:

1. i) a wear layer 110, which has a wood veneer, which is a real wood layer or a solid wood, for example oak. The wood veneer is anisotropic due to the wood fibers and therefore has a first preferred direction R1. Furthermore, the wood veneer shows pronounced swelling and shrinking behavior when there is a change in humidity (change between dry climate and humid climate).
2. ii) a stabilization layer 120, which has a material that, in contrast to a wood veneer layer, does not show any swelling and shrinkage behavior when the humidity changes. In principle, the stabilization layer does not contain any wood. In one example, the stabilization layer 120 is formed as a fiber layer integrated into a synthetic resin matrix, which is reinforced by fibers (eg glass fiber). However, other advantageous configurations are also possible, for example as a viscose mat. The stabilization layer preferably has anisotropy, particularly when using fibers, for example. This can result in a fourth preferred direction R4, which is coordinated with the first preferred direction R1. The material preferably has a high modulus of elasticity compared to that of the wear layer 110.
3. iii) a first base layer 130, which has an anisotropic material and thus a second preferred direction R2.
4. iv) a second base layer 140, which also has an anisotropic material and thus a third preferred direction R3.

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

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

In the example shown, the first preferred direction R1 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 R1 and the third preferred direction R3. In a preferred example, the fourth preferred direction R4 is formed transversely to the first preferred direction R1, but does not form a counterlayer 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 subsurface laying unit 100 has an exemplary thickness of 4.2 mm, with the connecting structure 150 exemplarily having a thickness of 1 mm. The wear layer 110 has a thickness in the range 0.4 mm to 0.9 mm, depending on the wood veneer used.

Below the subsurface laying unit 100, a subsurface 200 is shown, which has the subsurface connecting layer 160. This serves as a subsurface covering for the actual subsurface floor 201, e.g. a screed. In the example shown, the subsurface connecting layer 160 is designed as a magnetic foil, which is laid (rolled out) floating on the subsurface floor 201. If the connection structure 150 and the subsurface connection structure 160 are magnetically coupled, the subsurface laying unit 100 is laid on the subsurface 200 in a floating or adhesive-free manner.

When using a plurality of subsurface laying units 100, as described above, to cover the subsurface 200, they are all laid floating and free of frontal connecting elements. This means that at least some of the laid subsurface laying units 100 are movable in the vertical direction and thereby enable a completely new walking experience and are also particularly easy to replace later.

Figure 2 shows a cross-sectional view of a subsurface laying unit 100 according to a further exemplary embodiment of the invention. The structure is that of Figure 1 very similar. In addition, a connecting layer 135 is provided, which is arranged between the first base layer 130 and the second base layer 140. The bonding layer 135 includes an adhesive and can be targeted to produce certain desired properties.

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

Figure 4 clearly shows the overall path of the swelling and shrinkage behavior of the subsurface laying unit according to an exemplary embodiment of the invention in wet climates and dry climates. Through the in Figure 3 The curvatures described result in a total travel of 0.08 mm. This is a particularly advantageous and very short overall distance, which is even smaller than with a large number of fully glued multi-layer parquets.

In addition, it should be noted that “having” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Furthermore, it should be noted that features or steps that have been described with reference to one of the above-described exemplary embodiments can also be used in combination with other features or steps of other above-described embodiments. Reference symbols in the claims are not to be viewed as a limitation.

Reference symbols

100

Underground laying unit

101

Front side lengthwise

102

Front side across

110

wear layer

120

stabilization layer

130

First base layer

135

connecting layer

140

Second base layer

150

Connection structure

160

Underground connection structure

200

underground

201

Underground soil

R

preferred direction

Claims (15)

1. A subsurface laying unit (100), in particular a floor panel or a wall panel, for floating laying on a subsurface (200), the subsurface laying unit (100) com prising:
   a wear layer (110) having a wood veneer, the wear layer having a first preferred direction (R1);

   a stabilization layer (120) having a material that exhibits substantially no swelling and shrinkage behavior in the event of a change in humidity;

   a first support layer (130) having a second preferred direction (R2);

   a second support layer (140) having a third preferred direction (R3); and

   a connection structure (150) configured to provide a releasable connection to the subsurface (200);

   wherein the preferred directions (R1, R2, R3) are coordinated with one another in such a way that the subsurface laying unit (100) is substantially self-stabilized in the event of changes in humidity with regard to the swelling and shrinkage behavior.
2. The subsurface laying unit (100) according to claim 1,
   wherein the subsurface laying unit (100) is free of connecting elements to further subsurface laying units (100) on all end faces (101, 102).
3. The subsurface laying unit (100) according to claim 1 or 2,
   wherein the connecting 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-in connection, a plug-in connection, a tongue and groove connection, a hook-and-loop fastener 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 subsurface laying unit (100) according to any one of the preceding claims,
   wherein the subsurface laying unit (100) has a thickness of 4.8 mm or less, in particular 4.2 mm or less.
5. The subsurface laying unit (100) according to any one of the preceding claims,

   wherein the connecting 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 0.2 to 1.1 mm, in particular in a range of 0.4 mm to 0.9 mm.
6. The subsurface laying unit (100) according to any one of the preceding claims,

   wherein the first support layer (130) and/or the second support layer (140) has a further wood veneer,

   in particular, wherein at least one wood veneer has a real wood layer.
7. The subsurface laying unit (100) according to any one of the preceding claims,

   wherein the first preferred direction (R1) and the third preferred direction (R3) are arranged substantially parallel to each other; and/or

   wherein the second preferred direction (R2) is arranged substantially perpendicular to the first preferred direction (R1) and the third preferred direction (R3).
8. The subsurface 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 (R1).
9. The subsurface 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 fiberboard, a material with a high modulus of elasticity compared to the wear layer (110), an anisotropic material.
10. The subsurface laying unit (100) according to any one of the preceding claims, further comprising:

    a connecting layer (135), which is arranged between the first support layer (130) and the second support layer (140),

    in particular, wherein the connecting layer (135) comprises an adhesive and/or a natural resin.
11. A subsurface covering, in particular a floor covering or a wall covering, comprising:

    a plurality of subsurface laying units (100) according to any one of claims 1 to 10,

    wherein the plurality of subsurface laying units (100) are laid on the subsurface (200) in a floating manner and free of frontal connecting elements.
12. The subsurface covering according to claim 11,
    wherein at least one of the laid subsurface laying units (100) is at least partially movable in a vertical direction.
13. The subsurface covering according to claim 11 or 12, further comprising:
    a subsurface connection structure (160) which is laid on a subsurface floor (201) and which is releasably connected to the connection structure (150).
14. The subsurface covering according to claim 13,
    wherein the connection structure (150) comprises a magnetic layer, and wherein the subsurface connection structure (160) comprises a further magnetic layer which is laid in a floating manner on the subsurface floor (201).
15. A method for laying subsurface laying units (100), the method comprising:

    providing a plurality of subsurface laying units (100) according to any one of claims 1 to 10;

    providing a subsurface connection structure (160) on a subsurface floor (201);

    laying the plurality of subsurface laying units (100) such that the connecting structures (150) are releasably coupled to the subsurface connection structure (160);

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

    replacing the at least one subsurface laying unit (100) with a further subsurface laying unit (100).

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