EP4248033A1

EP4248033A1 - Floor panel

Info

Publication number: EP4248033A1
Application number: EP21806403.8A
Authority: EP
Inventors: Kristof van Vlassenrode; Quinten CHRISTIAENS
Original assignee: Flooring Industries Ltd SARL
Current assignee: Unilin BV
Priority date: 2020-11-18
Filing date: 2021-11-09
Publication date: 2023-09-27
Also published as: WO2022106957A1; EP4001546A1; CN116601365A; US20240011306A1; KR20230107623A; CA3196687A1

Abstract

Floor panel comprising a substrate (20), a decorative layer (22) and a wear layer (24), the decorative layer (22) being positioned between the substrate (20) and the wear layer (24). At least one of the substrate, the decorative layer and the wear layer comprises a thermoplastic synthetic material. The floor panel (10) further includes a foamed backing layer (26) attached to a side of the panel opposite to the wear layer (24), the foamed backing layer having a density of at least 120 kg/m³ and preferably a compressive strength value as determined in accordance with ASTM D 3575-91 (25 %) of at least 210 kPa.

Description

Floor Panel.

The present invention relates to a floor panel comprising a substrate, a decorative layer and a wear layer.

The invention is particularly interesting for being applied with floor coverings wherein at least one of the substrate, decorative layer and said transparent wear layer comprises thermoplastic synthetic material.

Such floor coverings are already well-known as such. For example, this may relate to so- called vinyl tiles or so-called LVT (Luxury Vinyl Tiles), or to wall-to-wall coverings. In said cases, the thermoplastic material relates to so-called soft PVC (Poly Vinyl Chloride), or PVC comprising a percentage of plasticizers, for example, of 5 to 20 percent by weight or even to 35 percent by weight or more. Herein, the decorative layer relates to a print, the decor of which may form a representation of a wood or stone pattern or any other pattern, such as a fancy pattern. On the surface of the panel, namely in said wear layer, a relief or structure may be provided, such as a wood or stone structure, respectively.

A disadvantage with floor coverings comprising soft PVC, particularly when the substrate is made from soft PVC, is that irregularities of the subfloor on which the floor covering is laid are telegraphed over time through the floor covering and become discernible on the visible surface of the floor covering. This undesirable effect can be mitigated by making the substrate of a more rigid material, such as rigid PVC. However, floor panels incorporating rigid PVC may have poor sound absorption properties.

It is known from US 8,640,824 B2 to provide a vinyl tile with an integral acoustical layer comprising a crumb rubber portion and a polyurethane foam component. A potential disadvantage with such a vinyl tile is that the acoustical layer is relatively thick. Not only does the thickness of the acoustical layer increase the total thickness of the floor panel or tile, its compressibility may lead to the surface of the floor covering sinking locally when walked upon. It is therefore an object of the present invention to provide a floor panel having favourable sound insulation properties, while being stable and easily installed.

This object is achieved by a floor panel in accordance with the first aspect of the invention, wherein the floor panel comprises a substrate, a decorative layer and a wear layer, the decorative layer being positioned between the substrate and the wear layer. At least one of the substrate, the decorative layer and the wear layer comprises a thermoplastic synthetic material. The floor panel further comprises a foamed backing layer attached to a side of the panel opposite to the wear layer. The foamed backing layer has a density of at least 120 kg/m³ and preferably a compressive strength value as determined in accordance with ASTM D 3575-91 (25 %) of at least 210 kPa. In this manner, the backing layer can be made relatively thin whilst still providing adequate sound insulation properties. Consequently, the materials constituting the substrate, decorative layer and wear layer may be selected to impart desired stability, and hence ease of installation, to the panel.

More particularly, the inventors have found that utilizing a foamed backing layer of at least 120 kg/m³ and a compressive strength value of at least 210 kPa implies that the backing layer is sufficiently lofty to attenuate sound but sufficiently firm to prevent excessive vertical movement when walked upon. These advantageous properties are particularly beneficial when the foamed backing layer has a thickness of between 0.50 mm and 1.0 mm. A preferred thickness interval is between 0.60 mm and 0.90 mm, more preferably between 0.70 mm and 0.80 mm. In a particularly advantageous embodiment of the invention the foamed backing layer has a thickness of about 0.75 mm.

The foamed backing layer may have a compressive strength value within the range of 250 kPa to 750 kPa, preferably 400 kPa to 700 kPa, more preferably 550 kPa to 650 kPa. Its density may be within the range of 130 kg/m³ to 350 kg/m³, preferably 160 kg/m³ to 300 kg/m³, more preferably 190 kg/m³ to 270 kg/m³. Although, for a particular material, there is a correlation between the density and compressive strength, the actual correlation will vary between materials. Consequently, an advantageous foamed backing layer may have a compressive strength value within the range of 400 to 700 kPa and a density within the range of 130 kg/m³ to 350 kg/m³ or within the range of 160 kg/m³ to 300 kg/m³. More specifically, a foamed backing layer having a compressive strength value within the range of 400 to 700 kPa may have a density within the range of 190 kg/m³ to 270 kg/m³. Similarly, other advantageous foamed backing layers may have a compressive strength value within the range of 550 to 650 kPa and a density within the range of 130 kg/m³ to 350 kg/m³ or within the range of 160 kg/m³ to 300 kg/m³. The same holds true for foamed backing layers with a compressive strength value within the range of 550 to 650 kPa and a density within the range of 190 kg/m³ to 270 kg/m³.

Although there are particular benefits associated with using a foamed backing layer having the claimed densities and compression strength values, it is to be understood that floor panels having advantageous properties may be attained even if the backing layer does not exhibit the recited compressive strength values. In particular, if the floor panel is provided with a reinforcement layer and/or depending on the material or materials comprised in the substrate, the floor panel may still offer favourable sound insulation properties, stability and ease of installation.

A suitable material for the foamed backing layer is a cross-linked polyethylene, for example a polyethylene which is cross-linked by irradiation, commonly referred to as IXPE (Irradiated Crosslinked PolyEthylene). According to a variant an open or closed cell foamed polyvinyl chloride may be opted for. According to still another variant a polyurethane or polyisocyanurate foam may be opted for.

Generally, it is valid that the thermoplastic synthetic material used in the floor panel of the present invention is selected from the following group: polyvinyl chloride (PVC), polyethylene, polypropylene, polyethylene terephthalate and polyurethane. However, other synthetic materials are not excluded.

Preferably, the substrate comprises polyvinyl chloride (PVC), preferably of the rigid type. Although a rigid PVC offers the advantage that irregularities of the underlying subfloor are less likely to be transmitted through the panel, it is conceivable that soft PVC or semi-rigid PVC be used for at least some regions of the substrate. In this respect, the terms “rigid”, “semi-rigid” and “flexible” (i.e. soft) are to be understood as follows:

- a rigid thermoplastic material is a thermoplastic material comprising plasticizers in an amount of maximum 15 phr, limits included; the rigid thermoplastic material may also comprise no plasticizer at all - a semi-rigid thermoplastic material is a thermoplastic material comprising plasticizers in an amount of between 15 and less than 20 phr, and

- a flexible thermoplastic material is a thermoplastic material comprising plasticizers in an amount of at least 20 phr.

One or more of the plasticizers from the following group may be used: DOP, DINCH, DINP,DOTP and/or epoxidized soybean oil.

Preferably, the substrate comprises filler materials, for example chalk, limestone, talc or sand. The content of filler materials may range between 5 and 80 percent by weight. Preferably, an amount of filler materials is present in the substrate material at a rate of 40 to 65 percent by weight. Such highly filled materials may lead to a higher weight and a better sound absorption, as well as to a more stable installation and a reduced thermal expansion.

Preferably, the substrate is a solid material, i.e. free of internal voids or foam. Such substrate can have an increased indentation resistance as compared to a foamed substrate. This is of importance considering the presence of a backing layer that may support the substrate to a lesser extent as compared to a similar floor panel without such backing.

In a further aspect to the invention, a reinforcement layer may be incorporated in the substrate. Depending on the form of reinforcement layer, its presence may lead to improved indentation resistance, thereby allowing the use of softer substrate material and/or softer material in the backing layer.

In one embodiment of the invention the reinforcement layer has an open structure. Consequently, substrate material may pass through openings in the structure to thereby fixedly incorporate the reinforcement layer in the substrate. A suitable material for the reinforcement layer is glass-fibre, preferably in the form of a fleece, a nonwoven cloth or a net. The reinforcement layer will improve the thermal dimensional stability of the substrate of the floor panel. A consequence of this is that, even though the material of the substrate and that of the foamed backing layer may have significantly different coefficients of thermal expansion, the relative size change between the two components will not be so great as to affect the reliability of the, often glued, connection between the substrate and the foamed backing layer. The positioning of the reinforcement layer within the substrate may influence the stability imparted to the floor panel. In a preferred embodiment, the reinforcement layer within the substrate is closer to the foamed backing layer than to the decorative layer.

Preferably, the decorative layer is in the form of a printed thermoplastic synthetic film. This may relate, for example, to a hard or soft PVC film having a thickness of 0.03 mm to 0.15 mm, preferably between 0.07 and 0.11 mm or between 0.08 mm and 0.10 mm. According to an alternative, the decorative layer may be a printed decor provided on an upper surface of the substrate by forming this decor, by means of any printing technique, directly on the substrate. In such case, it is desirable to prepare the substrate surface by means of, for example, a plastisol of the respective thermoplastic material for forming a uniform background colour for the printed decor. Preferably, such decor is printed by means of UV- based inks. According to another alternative, the decorative layer may be in the form of a decor which is provided on the wear layer, more particularly on the side thereof which is intended for being directed towards the substrate. Herein, this relates to a so-called "reverse" print, wherein the usual colour sequence of the inks is reversed. In such case, too, it is desirable to prepare the substrate layer with such plastisol or to provide a uniform background colour for the printed decor in any other manner, for example, by providing a coloured or white thermoplastic film underneath the printed wear layer. Here, too, such decor is preferably printed by means of UV-based inks. It is not excluded that instead of UV-based inks, water-based inks are used to print the decor in either of the alternatives mentioned here above.

It is noted that using a hard PVC film as a decorative layer, namely a PVC film without plasticizers, or of a PVC film having a percentage of plasticizers which is lower than 5 percent by weight, may be advantageous for obtaining a good registering between the printed decor and the structure of the wear layer. Due to the low percentage of plasticizer, such PVC films are less subject to dimensional alteration.

The wear layer is a thermoplastic synthetic material and is preferably transparent to thereby allow the decor of the decorative layer to be visible therethrough. A preferred material is transparent PVC, for example a soft PVC. The wear layer preferably shows a relief comprising a plurality of recesses. The relief may correspond to a printed decor, such that a so-called structure in register with the printed decor is obtained. In the case of a printed decor which represents a wood pattern with wood nerves, this may relate to a structure of a plurality of impressions or recesses in the form of wood pores which follow the course of the wood nerves, and/or a line structure corresponding to the course of the wood nerves. According to another example, this may relate to a structure which imitates joints or chamfers between a plurality of panels and corresponds to a joint or border between panels represented in the printed decor. It will be appreciated that the recesses forming the relief may vary in size and shape. For example, the depth of the recesses may vary. This also applies to the area of the opening to the recesses.

The wear layer has a thickness of at least 0.15 mm and still better at least 0.30 mm, however preferably less than 1.0 mm. An advantageous range is between 0.40 and 0.70 mm. A floor panel having a wear layer of between 0.40 mm and 0.70 mm has the advantage that an effective wear resistance can be obtained for residential applications without resorting to solid wear-enhancement additives such as aluminium oxide. For example, it is possible to achieve an IP value (Initial wear point) of 2000 or more in the Taber tests, as described in EN 13329, Annex E.

The floor panels of the invention preferably have a total thickness of 2.0 mm to 5.0 mm, preferably between 3.0 mm and 4.0 mm. Preferably, the substrate, which comprises one or more substrate layers, has a thickness of 1.3 mm to 5.0 mm. Preferably, the substrate forms at least half of the thickness of the floor panel.

The panels of the invention preferably have a width of 8 cm or more. Particularly preferred dimensions relate to a width situated between 15 and 22 cm and a length situated between 118 and 220 cm. It is clear that this relates to panel-shaped elements. However, it is not excluded that the invention may be applied to floor panels in the form of rectangular tiles. In particular, the invention relates to so-called LVT (Luxury Vinyl Tile) in plank format or in tile format.

The floor panel of the invention may comprise an upper surface with a lowered edge region at one or both edges of a pair of opposite sides. Such lowered edge region may be in the form of a chamfer, i.e. bevelled, or may comprise a flat bottom. In the latter case, an imitation of a cement joint may be sought. In any such case, the lowered edge region mitigates the risk that a possible temporary difference in height between adjacent floor panels in a floor covering would lead to excessive wear. As explained, the backing layer applied in connection to the present invention delivers an ideal compromise between compressive strength and sound attenuation. This compromise does not necessarily lead to the absence of vertical motion of the floor panels. On the contrary, the slightly resiliently moving floor covering may deliver comfort when being walked upon. Temporary height differences may thus still occur when the floor is being walked upon, or when heavy objects are on the floor covering. The provision of a lowered edge region may alleviate the consequences of such height differences. Moreover, the lowered edge regions may hide such temporary imperfections from the average person walking on the floor.

According to one embodiment, the floor panel of the invention may comprise vertical edges at one or more of its sides. According to another embodiment, the floor panel of the invention may comprise profiled edges at one or more pairs of opposite sides. According to a first possibility, such profile may be such that only the upper edges of adjacent floor panels touch each other. As an example, such profile at opposite sides may consist of inwardly inclined flanks converging at said upper edge. According to a second possibility, the profile at one or more pairs of opposite sides may be such that the profiles of adjacent floor panels at least partially overlap each other, for example forming a shiplap joint, or a tongue-in-groove joint. According to this second possibility an increased vertical stability of the floor panels in the floor covering is obtained.

According to a second independent aspect, the present invention also concerns a floor covering assembled from floor panels as described by means of the first aspect and/or the preferred embodiments thereof. Preferably, such floor panels are loosely installed over the subfloor, or are glued to the subfloor. In either case an additional layer may be available between the subfloor and the panel, for example a vapor blocking layer.

The invention will be described in the following by way of example only and with reference to the attached drawings in which:

Fig. 1 represents a panel of a floor covering with the characteristics of the invention; Fig. 2, on a larger scale, represents a cross-section according to the line II-II indicated in Fig. 1;

Fig. 3 is a view similar to Fig. 2 though illustrating a different embodiment;

Figs.4 to 6 are cross-sectional views including a side edge of three possible embodiments of a floor panel according to the invention, and

Fig. 7 is a cross-sectional view of edge regions of two adjacent floor panels.

In the drawings, reference number 10 generally denotes a floor panel in accordance with the present invention. The floor panel 10 is generally rectangular and has a first pair of opposite sides 12, 14 and a second pair of opposite sides 16,18. In Fig. 1 the first pair of opposite sides is longer than the second pair of opposite sides, though it is to be understood that the principles of the present invention are applicable to panels and tiles of any shape, including tiles having sides of the same length, i.e. square tiles.

As may be gleaned from Fig. 2, the floor panel 10 of the invention comprises a plurality of layers, including a substrate 20, a decorative layer 22 and a wear layer 24. The decorative layer 22 is positioned between the substrate 20 and the wear layer 24. At least one, preferably two, though most preferably all three of the substrate 20, decorative layer 22 and wear layer 24 comprises a thermoplastic synthetic material such as PVC. According to the invention, the floor panel 10 further comprises a foamed backing layer 26 attached to a side of the floor panel opposite to the wear layer 24. To impart desired properties to the floor panel, the foamed backing layer has a density of at least 120 kg/m³ and may optionally have a compressive strength value as determined in accordance with ASTM D 3575-91 (25 %) of at least 210 kPa.

The floor panel of the present invention is intended to be laid on a subfloor, either loosely or adhered thereto. A floor covering is achieved by laying a plurality of the floor panels next to each other in essentially abutting contact over a desired subfloor area.

The floor panel illustrated in Fig. 2 includes additional optional layers. One such layer is a reinforcement layer 28 which is incorporated into the substrate 20. A suitable material for the reinforcement layer is a glass-fibre fleece or a nonwoven cloth. The fleece or cloth may have a basis weight of between about 20 g/m² and 40 g/m², for example about 30 g/m². Rather than a fleece or nonwoven cloth, the reinforcement may be in the form of a net. To ensure strong bonding of the reinforcement layer to the substrate, the reinforcement layer may have an open structure. The reinforcement layer 28 is illustrated as being within the substrate 20 closer to the foamed backing layer 26 than to the decorative layer 22. However, it is conceivable that the reinforcement layer 28 be located closer to the decorative layer 22 than to the foamed backing layer 26, depending on the relative rigidity of the materials making up the constituent layers of the floor panel.

Another optional layer is a topcoat 30. The topcoat 30 may be a transparent or translucent lacquer layer. The lacquer layer may comprise a solvent- or water-based UV-curable PU dispersion. The lacquer layer may comprise ceramic particles. These particles enhance properties such as scratch resistance and wear resistance. The ceramic particles may include aluminium oxide particles. Preferably, these particles have a diameter of from 2 to 20 microns. The particles can be coated with silanes in order to better embed them in the PU dispersion. The solid matter content of the PU dispersion may be from 30 wt.% to 40 wt.%.

Although not shown in the drawings, an additional lacquer layer may form the uppermost layer of the floor panel. Preferably, the additional layer is transparent or translucent and can be used to determine the gloss degree of the floor panel. The additional lacquer layer may be a UV-curable lacquer, such as polyurethane, with a solid matter content of 100 %. Such a layer has enhanced mechanical and chemical resistance, something which is of course beneficial for properties such as wear resistance, scratch resistance and stain resistance.

Considering the various layers of the floor panel in more detail, the foamed backing layer 26 may have a thickness of between 0.50 mm and 1.0 mm. A preferred thickness interval is between 0.60 mm and 0.90 mm, more preferably between 0.70 mm and 0.80 mm. In a particularly advantageous embodiment of the invention the foamed backing layer has a thickness of about 0.75 mm. A suitable material for the foamed backing layer is a polyethylene which is cross-linked by irradiation, commonly referred to as IXPE. Other possible materials include an open or closed cell foamed polyvinyl chloride, a polyurethane foam or a polyisocyanurate foam. The foamed backing layer 26 may have a compressive strength value within the range of 250 kPa to 750 kPa, preferably 400 kPa to 700 kPa, more preferably 550 kPa to 650 kPa. Its density may be within the range of 130 kg/m³ to 350 kg/m³, preferably 160 kg/m³ to 300 kg/m³, more preferably 190 kg/m³ to 270 kg/m³.

The substrate 20 may comprise polyvinyl chloride (PVC), preferably of the rigid type. Although a rigid PVC offers the advantage that irregularities of the underlying subfloor are less likely to be transmitted through the panel, it is conceivable that soft PVC or semi-rigid PVC be used for at least some regions of the substrate. Indeed, if a reinforcement layer 28 is present, the substrate material need not be as rigid as for a panel without a reinforcement layer.

As shown in Fig. 2, the substrate 20 itself may consist of a plurality of layers 32, 34, 36, 38. In this manner, compatibility between the substrate 20 and further layers of the floor panel can be optimized. Thus, the substrate may comprise a top layer 32, the material of which is selected to be compatible with the material of the decorative layer 22. Similarly, the substrate may have a backing layer 34 made of a material which advantageously allows the foamed backing layer 26 to be adhered thereto. The substrate 20 may also include an upper core layer 36 and a lower core layer 38, with the reinforcement layer 28 being positioned therebetween. The materials of the upper core layer and the lower core layer may be the same. Preferably, the material making up the substrate is a solid material, i.e. it is free from internal voids or foam.

The foamed backing layer 26 may be adhered to the substrate 20, more particularly to the backing layer 34 of the substrate, using any suitable adhesive. Preferred adhesives are polyurethane reactive adhesive, also known as reactive hot melts. This type of adhesive is a one-part formulation with the bond forming in two stages. In a first stage, the adhesive cools back down and solidifies to reach its holding strength. In a second stage, a moisture-curing reaction takes place, typically over 24 to 48 hours, to reach final structural strength.

The decorative layer 22 may be in the form of a thermoplastic synthetic foil or film having a printed or imprinted decor thereon. The foil or film may relate, for example, to a hard or soft PVC film having a thickness of 0.03 mm to 0.15 mm, preferably between 0.07 and 0.11 mm or between 0.08 mm and 0.10 mm. The decor may represent a wood pattern with wood nerves, a stone pattern or a fancy pattern. Although it is preferred that the decor is printed by means of UV-based inks, it is not excluded that water-based inks may be used.

The wear layer 24 may be a thermoplastic synthetic material and is preferably transparent to thereby allow the decor of the decorative layer 22 to be visible therethrough. A preferred material is transparent PVC, for example a soft PVC. The wear layer preferably shows a relief comprising a plurality of recesses 40 (see Fig. 1). The relief may correspond to a printed decor, such that a so-called structure in register with the printed decor is obtained. In the case of a printed decor which represents a wood pattern with wood nerves, this may relate to a structure of a plurality of impressions or recesses 40 in the form of wood pores which follow the course of the wood nerves, and/or a line structure corresponding to the course of the wood nerves. According to another example, this may relate to a structure which imitates joints or chamfers between a plurality of panels and corresponds to a joint or border between panels represented in the printed decor. It will be appreciated that the recesses forming the relief may vary in size and shape. For example, the depth of the recesses may vary. This also applies to the area of the opening to the recesses.

The wear layer 24 has a thickness of at least 0.15 mm and still better at least 0.30 mm, however preferably less than 1.0 mm. An advantageous range is between 0.40 and 0.70 mm.

In one embodiment, the wear layer 24, the decorative layer 22 and the top layer 32 may be flexible PVC layers and may include a relatively high amount of plasticizer. To provide adequate strength and stability to the floor panel, the backing layer 34, the upper core layer 36 and the lower core layer 38 of the substrate 20 may be more rigid than the top layer 32 of the substrate.

Fig. 3 depicts a cross-section through a second embodiment of a floor panel in accordance with the invention. This floor panel differs from that illustrated in Fig. 2 only in that the substrate 20 consists of a single layer of material, preferably a single layer of rigid PVC. Consequently, the floor panel of Fig. 3 does not have a reinforcement layer incorporated in the substrate. Nevertheless, it is to be understood that a floor panel in accordance with the invention may have a single layer substrate and a reinforcement layer on either or both sides of the substrate. However, since it is advantageous if the decorative layer 22 overlies a smooth surface, it is preferred that any reinforcement layer be located between the foamed backing layer 26 and the single layer substrate 20.

Figs. 4, 5 and 6 illustrate possible lowered edge regions 42, 44, 46, respectively, which may be incorporated into the upper surface of floor panels 10 of the present invention. It is to be understood that the lowered edge regions may be applied along a single side 12, 14, 16, 18 of the floor panel, along a pair of opposed sides or along all four sides. As illustrated, the lowered edge regions 42, 44, 46 may be in the form of a bevel or chamfer 48, 50, 52, respectively. However, it is to be understood that the lowered edge region may comprise a flat bottom, possibly mimicking the appearance of a cement- or grouted joint. The lowered edge regions 42, 44, 46 are shown as being applied to the upper surface of panels having a multi-layered substrate 20, but it is to be understood that floor panels having a single layer substrate may also have corresponding lowered edge regions.

In Fig. 4, the chamfer or bevel 48 forming the lowered edge region 42 passes through a depth d of the wear layer 24, the depth d being less than the total thickness t of the wear layer. In this manner, the underlying decorative layer 22 is still covered by wear layer material. To provide the desired effect of masking any vertical movement between adjacent floor panels, it is advantageous if the chamfer or bevel has a depth d of at least 50 %, preferably at least 60 %, more preferably at least 70 %, of the entire wear layer thickness t. Depending on what visual effect is desired, the chamfer or bevel may subtend an angle of from 6° to 25°, preferably 8° to 20°, more preferably 10° to 15° and most preferably about 11° to the upper surface of the floor panel.

In Fig. 5, the chamfer or bevel 50 forming the lowered edge region 44 subtends an angle of about 45° to the upper surface of the floor panel 10, though the skilled person will appreciate that this angle may have a value of from 30° to 60°, preferably from 40° to 60°. The chamfer or bevel 50 passes through the entire thickness of the wear layer 24, and may, as illustrated, also pass through the decorative layer 22 and into an upper region of the substrate 20. In the case of a multi-layered substrate, the chamfer or bevel may extend though at least a part of the top layer 32. Optionally, the chamfer or bevel 50 may be covered by a cover layer 54. The cover layer 54 may be a lacquer layer, for example of the same type as that used for the optional topcoat 30. Alternatively, or in combination, the cover layer may be coloured to enhance the impression of a v-shaped groove between two adjacent panels.

In Fig. 6, the chamfer or bevel 52 forming the lowered edge region 46 is in the form of a pressed-down bevel. In other words, the edge region is subjected to pressure and, optionally, heat, to create a plastic deformation of the floor panel 10 in the edge region. In this manner, no material has to be removed from the floor panel 10 to create the lowered edge region 46.

In the illustrated embodiments, the uppermost surface of the floor panels 10 is constituted by the optional topcoat 30, as described above with respect to Fig. 2. It is to be understood that forming the chamfer or bevels 48 and 50 in the Figs. 4 and 5 embodiments, respectively, will then involve removal of the topcoat material covering the portion of the wear layer 24 that is removed when forming the lowered edge regions 42, 44, respectively.

In the embodiments described above, the floor panels 10 comprise vertical edges at least at one or more of their sides 12, 14, 16, 18. According to a further embodiment, the floor panel 10 of the invention may comprise profiled edges at one or more pairs of opposite sides. One possible embodiment is illustrated in Fig. 7 in which a first side 12 of one panel is provided with a tongue 56 and a second side 14 of an adjacent panel is provided with a groove 58. The tongue 56 and the groove 58 are shown as being formed in the substrate 20 of the floor panels since this is generally the most rigid section of the panels. It will be understood that profiled edges may be incorporated in floor panels with a single layer substrate as well as in floor panels having a multilayer substrate. As a result of the tongue 56 engaging in the groove 58 of an adjacent panel, vertical stability of a thus laid floor covering is increased.

As also shown in Fig. 7, the floor panels may have profiled edges such that upper edges 60 of adjacent panels touch each other when laid. This may be attained by at least one side 12 of a panel having an inwardly inclined flank 62. In this manner, a gap 64 may be created between lower regions of adjacent panels, thereby allowing any dirt or debris on the subfloor to gather in the gap while still allowing the upper edges 60 to touch each other. Clearly, the provision of one or more inwardly inclined flanks 62 is not necessarily dependent on the presence of tongue-and-groove profiled edges. It is also to be understood that any material overlap between adjacent panels will contribute to improved vertical stability. Thus, whilst a tongue 56 and a groove 58 are illustrated in Fig. 7, this aspect of the invention may be attained by, for example a bulge and corresponding recess or a heel and corresponding recess. Indeed, any form of partial overlap is contemplated, for example the overlap provided by a shiplap joint.

Preferably, both the first pair of opposite sides 12, 14 and the second pair 16, 18 are provided with profiled edges.

The floor panels of the invention preferably have a total thickness of 2.0 mm to 5.0 mm, preferably between 3.0 mm and 4.0 mm. Preferably, the substrate has a thickness of 1.3 mm to 5.0 mm. Preferably, the substrate forms at least half of the thickness of the floor panel.

According to a second independent aspect, the present invention also concerns a floor covering assembled from any of the embodiments of floor panels 10 described above and/or preferred embodiments thereof. Preferably, the floor panels are loosely installed over a subfloor or adhered thereto. In either case, an additional layer may be provided between the subfloor and the floor panels, for example a vapour-blocking layer.

The present invention is in no way limited to the herein above described embodiments; on the contrary, such floor panels may be realized according to various variants within the scope of the appended claims.

Claims

Claims:

1.- Floor panel comprising a substrate (20), a decorative layer (22) and a wear layer (24), said decorative layer (22) being positioned between the substrate (20) and the wear layer (24), wherein at least one of the substrate, the decorative layer and the wear layer comprises a thermoplastic synthetic material, the floor panel (10) further comprising a foamed backing layer (26) attached to a side of the floor panel opposite to the wear layer (24), the foamed backing layer having a density of at least 120 kg/m³ and preferably a compressive strength value as determined in accordance with ASTM D 3575-91 (25 %) of at least 210 kPa.

2.- Floor panel according to claim 1, wherein the foamed backing layer (26) has a compressive strength value within the range of 250 to 750 kPa, preferably 400 to 700 kPa, more preferably 550 to 650 kPa.

3.- Floor panel according to claim 1 or 2, wherein the density of the foamed backing layer (26) has a density within the range of 130 kg/m³ to 350 kg/m³, preferably 160 kg/m³ to 300 kg/m³, more preferably 190 kg/m³ to 270 kg/m³

4.- Floor panel according to any of the preceding claims, wherein the foamed backing layer (26) has a thickness of between 0.50 mm and 1.0 mm, preferably between 0.60 mm and 0.90 mm, most preferably 0.70 mm and 0.80 mm.

5.- Floor panel according to any of the preceding claims, wherein the foamed backing layer (26) comprises cross-linked polyethylene.

6.- Floor panel according to any of the preceding claims, wherein the substrate (20) comprises polyvinyl chloride, preferably a rigid polyvinyl chloride.

7.- Floor panel according to any of the preceding claims, wherein a reinforcement layer (28) is incorporated in the substrate (20).

8.- Floor panel according to claim 7, wherein the reinforcement layer (28) has an open structure.

9.- Floor panel according to claim 7 or 8, wherein the reinforcement layer (28) comprises glass-fibre, preferably in the form of a fleece, a nonwoven cloth or a net.

10.- Floor panel according to any one of claims 7 to 9, wherein the reinforcement layer (28) within the substrate (20) is closer to the foamed backing layer (26) than to the decorative layer (22).

11.- Floor panel according to any of the preceding claims, wherein the panel has a total thickness of between 2.5 mm and 5.0 mm, preferably between 3.0 mm and 4.0 mm.

12.- Floor panel according to any of the preceding claims, wherein the decorative layer (22) is a printed PVC layer.

13.- Floor panel according to claim 12, wherein the printed PVC layer has a thickness of between 0.08 mm and 0.10 mm.

14.- Floor panel according to any of the preceding claims, wherein the wear layer (24) is a transparent PVC layer, and wherein the panel is preferably provided with a topcoat (30), the topcoat preferably being formed from a UV-curable lacquer layer, preferably of polyurethane.

15.- Floor panel according to any of the preceding claims, wherein the wear layer (24) comprises an upper surface in which a relief is realized, said relief comprising a plurality of recesses (40).