Description:

The invention pertains to a flooring composite, such as a carpet tile, a broadloom carpet, and an artificial turf comprising such a flooring composite, a method manufacturing such a flooring composite.

In house-holds and public buildings such as hotels, offices, hospitals and shops, broadloom carpets and carpet tiles can be found as flooring. Thereby, next to aesthetic requirements, carpets have to fulfill several requirements such as dimensional stability, resiliency, good/warm feel when walking over with naked feet and sound insulation in view of e.g. a reduction of impact sound or a reduction of reflecting sound.

Carpets can also be used in automotive, ships such as cruises and ferries aircrafts and trains. In these applications, and in particular in buildings, e.g. houses, the carpets have to fulfill further requirements such as low weight and sound insulation.

In common broadloom carpets and carpet tiles heavy layers are used as these heavy layers can improve the stability of the broadloom carpets and carpet tiles. Typical heavy layers are bitumen or polymeric layers which are added to the backside of broadloom carpets and carpet tiles. Further, such heavy layers support the broadloom carpet and carpet tiles when laid on a ground such that moving of a laid broadloom carpet and carpet tiles can be eliminated or at least reduced. However, such heavy layers have disadvantages in transport or handling during installation. Further, when carpets are used in automotive, planes or trains, it is desired that the broadloom carpet and the carpet tiles are lightweight as possible.

JP 2013220648 A discloses a folding-type honeycomb structure having high rigidity, which may be used as a vehicle floor panel, wherein cell halves are provided with an additional adhesive or welded together to ensure that the cell halves are firmly fixated to each other to provide rigidity.

The object of the invention is to provide a flooring composite which is lightweight, has sound insulating properties, a good dimensional stability and which may be Tollable at the same time. Further, the flooring composite shall be more suitable for recycling.

The object is solved by a flooring composite comprising a flooring surface and a folded core structure, wherein the flooring surface comprises a flooring face surface and a flooring back surface, and wherein the folded core structure is located adjacent to the flooring back surface, characterized in that said folded core structure is provided from an uncut flat body, by plastic deformation perpendicular to the plane of the uncut flat body such that three-dimensional structures comprising half cell walls and connection areas are formed, wherein the half cell walls are at an angle a to each other to provide a relaxed honeycomb structure or adjoin one another in the form of a honeycomb cell to provide a half-closed honeycomb structure, wherein the adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls. Preferably, the relaxed honeycomb structure and the half-closed honeycomb structure are formed by pushing the three-dimensional structures towards each other at predefined folding lines.

The folded core structure can be a half-closed honeycomb structure, such as for example disclosed by WO 2006/053407 A1. This half-closed honeycomb structure can be provided from an uncut flat body, which can be composed of a thermoplastic polymer or thermoplastic elastomeric polymer, by plastic deformation perpendicular to the plane of the material such that three-dimensional (3D) structures and connection areas are formed, i.e. half cell walls and small connection areas are formed (Fig. 3). Subsequently, the 3D-structures are pushed towards each other at predefined folding lines to form cells having cell walls adjoining one another in the form of a honeycomb cell. Thereby, the term “adjoining” means that the cell walls are in contact to each other, but the most of the adjoining cell walls can be free of bonding. Solely at one edge of the cell walls, the adjoining cell walls are connected to each other. The one edge of the cell walls is located in a first main surface of the folded core structure or in a second main surface of the folded core structure.

Thereby, the first main surface is established by parts of the folded core structure, which are extending the most above the plane of the x- and y- direction, and the second main surface is established by parts of the uncut flat body, which are extending the most below the plane of the x- and y-direction.

Within the scope of the invention, the uncut flat body has to be understood as a thin body, which is a one pieced body, i.e. which does not consist of multiple parts connected to each other to provide the extension of the uncut flat body in x- and y- direction. This means the uncut flat body consists of solely one body and is free of any connections, e.g. seams, glued portions or welded portions. Further, the term “provided from an uncut flat body” is understood to mean that the flat body is not cut to enable folding of the deformed sheet into a core having a three-dimensional structure. The uncut flat body may however be cut to provide a certain width and/or length of the uncut flat body before the uncut flat body is plastically deformed. It is therefore to be understood that the core having a three-dimensional structure is formed from an uncut flat body. In a preferred embodiment, the honeycomb cells comprised in the half-closed honeycomb structure and in the relaxed honeycomb structure are polygonal cells with a number n of walls. The number n is at least 3 and goes in principle to infinite, which is circular. Preferably, the number n has an even value, more preferably n has the value of 4, 6 or 8, and most preferably n has the value of 6. In the case of the relaxed honeycomb structure, it has to be understood that the number n of walls of the honeycomb cells refers to the number of walls of two half cell walls which are at an angle a to one another.

Preferably, the formed honeycomb cells are closed by the connection areas at one end of the honeycomb cell, such that the honeycomb structure is water and/or gas impermeable over its entire extension and the void volumes on one side of the folded core structure are not connected to void volumes on the other side of the folded core structure.

Alternatively, the formed honeycomb cells exhibit holes in the connection areas or are open at both ends, such that the void volumes on one side of the folded core structure are connected with the void volumes of the other side of the folded core structure.

The folded core structure can also be a relaxed honeycomb structure. This relaxed honeycomb structure is produced in the same manner as the half-closed honeycomb structure with the exception that the folding of the plastically deformed uncut flat body is stopped before the half cell walls meet together to form the half- closed honeycomb structure.

As the folding of the plastically deformed uncut flat body is stopped before the cell walls meet together, the half cell walls are at an angle a to each other. In a preferred embodiment, the angle a in the relaxed honeycomb structure is of at most 110°, preferably of at most 100°, more preferably of at most 90° even more preferably of at most 85°, and most preferably of at most 80°.

In another preferred embodiment, the angle a in the relaxed honeycomb structure is of at least 1 °, preferably of at least 25°, more preferably of at least 45°, and most preferably of at least 60°.

In a further preferred embodiment, the angle a in the relaxed honeycomb structure is up to 110°, preferably between 1 ° and 100°, more preferably between 25° and 90°, even more preferably between 40° and 85°, and most preferably between 60° and 80°.

Without being bound to theory, it is believed that an angle exceeding 110° will deteriorate the stability, e.g. the compression resistance, of the relaxed honeycomb structure, thus deteriorating the dimensional stability of the folded core structure, respectively of the flooring composite.

Due to the fact that the relaxed honeycomb structure is manufactured in the same manner as the half-closed folded honeycomb structure, the plastically deformed uncut flat body also comprises 3D-structures and connection areas such that the relaxed honeycomb structure can also be water impermeable and the void volumes on one side of the folded core structure are not connected void volumes on the other side of the folded core structure.

Without being bound to theory, it is believed that a flooring composite comprising a half closed honeycomb structure or a relaxed honeycomb structure has an improved, or at least sufficient, dimensional stability, in terms of reduced dishing and doming, and/or improved, or at least sufficient, stretching and compression resistance, at least in the machine direction and cross machine direction. Further, such a folded core structure can be used instead of heavy layers in broadloom carpets and carpet tiles, thus, the flooring composite is lightweight in view of common flooring composites. As the half cell walls are at an angle a to each other to provide a relaxed honeycomb structure, or adjoin one another in the form of a honeycomb cell to provide a half-closed honeycomb structure, wherein the adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls, the flooring composite can be rolled up.

The flooring composite comprising a half closed honeycomb structure or a relaxed honeycomb structure can be produced more efficiently as compared to the folding- type honeycomb structure of JP 2013220648 A, as the flooring composite does not require an additional adhesive or welding to ensure that the cell halves are firmly fixated to each other.

Within the scope of the present invention “machine direction” is understood to be the direction of production, as it is the largest dimension of the flooring composite, which can also be synonymously called x-direction. Further, the “cross machine direction” is the second largest dimension of the flooring composite, which is in plane with the machine direction and perpendicular to the machine direction, which can be synonymously called y-direction. Out of the plane and perpendicular to the machine direction and the cross machine is the third largest dimension of the flooring composite, which is the z-direction.

In a preferred embodiment, the relaxed honeycomb structure comprises half cells having a diameter dhaif of 0.5 mm to 30 mm, preferably of 1 to 20 mm, and more preferably of 1 to 15 mm, even more preferably of 1 to 10 mm, and most preferably of 1.5 to 5 mm.

In contrast to the half-closed honeycomb structure, the relaxed honeycomb structure is not fully folded, such that the connection area of a honeycomb cell comprises a kink. Thus, the diameter of the half cells dhaif of the relaxed honeycomb structure is determined by measuring the distance between the kink and the cell wall of the half cell of the relaxed honeycomb structure in the plane of the connection area, which is oriented parallel to the kink, wherein the distance is measured perpendicular to the kink and perpendicular to the parallel oriented honeycomb cell wall. To provide the diameter of the honeycomb cells of the relaxed honeycomb structure, the diameters dhaif of both half cells, which share the same connection area having a kink, have to be summed up (Fig. 3 and 6).

Preferably, the honeycomb cells comprised in the relaxed honeycomb structure have a diameter of 1 mm to 60 mm, preferably of 2 to 40 mm, and more preferably of 2 to 30 mm, even more preferably of 2 to 20 mm, and most preferably of 3 to 10 mm.

In another preferred embodiment, the half cells of the relaxed honeycomb structure have a height h of 1 mm to 60 mm, preferably of 2 mm to 20 mm, and more preferably of 3 to 15 mm, and most preferably of 3 to 10 mm.

In further preferred embodiment, the half cells of the half-closed honeycomb structure have a height h of 1 mm to 60 mm, preferably of 2 mm to 20 mm, and more preferably of 3 to 15 mm, and most preferably of 3 to 10 mm.

The method of determining the height of the half cells of the half-closed honeycomb structure is also applicable to the half cells of the relaxed honeycomb structure. The distance, i.e. the diameter and the height of the honeycomb cells are indicated by dashed lines in Figures 3, 5 and 6.

Preferably, the honeycomb cells comprised in the half-closed honeycomb structure or the relaxed honeycomb structure have a diameter of 1 mm to 60 mm, preferably of 2 to 40 mm, and more preferably of 2 to 30 mm, even more preferably of 2 to 20 mm, and most preferably of 3 to 10 mm and/or the honeycomb cells have a height of 1 mm to 60 mm, preferably of 2 mm to 30 mm, and more preferably of 3 to 20 mm, and most preferably of 3 to 10 mm. In a further preferred embodiment, the folded core structure is a half-closed honeycomb structure.

The advantage of a folded core structure, which is a half-closed honeycomb structure, is that the folded core structure has an improved dimensional stability, at least in z-direction in view of flooring without a folded core structure, as the half cell walls are directed perpendicular to the plane of the folded core structure.

A folded core structure could comprise adjoining cell walls of neighboring half cell walls in the half-closed honeycomb structure, which are bonded to each other (Fig. 1, 104a-d). Thereby, bonded to each other has to be understood that the adjoining cell walls of neighboring half cells are connected at least at two edges of each cell wall.

The full surfaces of the adjoining cell walls of neighboring half cells could be bonded to each other.

The adjoining cell walls could be bonded to each other by any suitable method such as mechanical bonding, chemical bonding and/or thermal bonding. The adjoining cell walls could be bonded chemically and/or thermally.

In the case, the adjoining cell walls would be bonded to each other, the folded core structure would have an improved dimensional stability in any direction as stretching and/or contraction of the folded core structure is eliminated or at least reduced. Thereby, it would also be possible that the bonding between the adjoining cell walls also improves the dimensional stability in z-direction as due to the bonded cell walls, the folded core structure is fixed in its folding. Further, due to the bonding of the adjoining cell walls, the folded core structure would also exhibit an improved bending stiffness and resistance against shear forces. Flowever, a folded core structure wherein the half cell walls are bonded to each other, e.g. over the full surfaces of the adjoining cell walls, requires more complex processing as compared to the folded core structure comprised in the flooring composite. Furthermore, a folded core structure wherein the half cell walls are bonded to each other, e.g. over the full surfaces of the adjoining cell walls, do not enable that the flooring composite can be rolled up.

In another preferred embodiment, the folded core structure comprises a thermoplastic polymer material or thermoplastic elastomeric polymeric material.

Without being bound to theory, it is believed that if the folded core structure comprises a thermoplastic elastomeric polymeric material, the folded core structure has an improved resiliency. Also, a broadloom carpet and/or a carpet tile comprising the folded core structure comprising a thermoplastic elastomeric polymeric material may have an improved dampening character, such that walking of a person on the broadloom carpet and/or carpet tile has a comfortable feeling.

Thereby, the thermoplastic polymeric material is preferably selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2- furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers blends and combinations thereof.

In another preferred embodiment, the thermoplastic polymeric material of the folded core structure comprises a multi-layered laminate. Preferably, the thermoplastic polymeric material of the multi-layered laminate is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2- furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and blends thereof.

An example of such a laminate can comprise a copolymer and homopolymer of e.g. polyethylene terephthalate. Such a multi-layered laminate can be a PET-GAG, wherein the laminate comprise glycol modified polyethylene terephthalate (PET-G) and amorphous polyethylene terephthalate (PET-A).

In a preferred embodiment, the multi-layered laminate is a three-layered laminate comprising a core layer a first sheath layer and a second sheath layer. The layers are oriented co-planar to each other, and second sheath layer is located co-planar at one side of the core layer, which is facing away from the first sheath layer. Preferably, the core layer has a melting temperature higher than the melting temperature of the first sheath layer and/ the second sheath layer. Preferably, the melting temperature is at least 5°C, preferably 10°C, more preferably 15°C and most preferably 20°C higher than the melting temperature of the first sheath layer and/or the second sheath layer.

In another preferred embodiment, the three-layered laminate can be one of the combinations e.g. PP/PET/PP, PA/PET/PA, PVB/PA/PVB, PVB/PET/PVB or PET- GAG.

The thermoplastic polymeric material and the thermoplastic elastomeric polymeric material of the folded core structure can comprise suitable additives such as flame retardants, antioxidants, fungicides, plasticizer and/or filler materials.

Preferably, the filler materials are particles such as talcum and grinded stone hard particles. In a preferred embodiment, the filler material has a weight of at least 10 wt.-%, preferably of at least 20 wt.-%, more preferably of at least 30 wt.-%, and most preferably of at least 40 wt.-% in view of the weight of the folded core structure. Without being bound to theory, it is believed that by having grinded stone hard particles added to the thermoplastic polymeric material or to the thermoplastic elastomeric polymeric material, the folded core structure comprises an improved hardness and heat distortion temperature.

In a further preferred embodiment, the folded core structure is water impermeable and the void volumes on one side of the folded core structure are not connected to void volumes on the other side of the folded core structure.

Since the folded core structure can be water impermeable, the folded core structure can be used as a water barrier. Thus, the flooring composite can also be used at locations having high humidity and/or on moist grounds.

In a preferred embodiment, the void volumes in at least one side of the folded core structure is filled with a substrate. Preferably, the substrate is a heated fluid or solid particles. The heated fluid can be a heated thermoplastic polymeric material or a heated thermoplastic elastomeric polymeric material. The solid particles can talcum or grinded stone hard particles.

The filling of the void volumes can be increased the weight of the flooring composite, if necessary, which could improve the grip of the flooring composite on the ground.

In a preferred embodiment, the folded core structure comprises heating means, cooling means, lighting, data sensing, data transferring, cables and/or further electrical component such as smart home components.

The heating means can be wires, spot or films of conductive component. The conductive component can comprise any suitable conductive metal such as copper, iron, aluminum, lead, zinc, tin, nickel, chromium, platinum, palladium, silver, gold, and any alloy or combination thereof. Thereby, the heating means can heat the folded core structure, respectively the flooring composite, by conducting electricity through the conductive material or by infrared irradiation of the conductive material.

Heating means can also be small tubes which a heated medium can flow through, such as in an underfloor heating.

The cooling means can be tubes comprising a cooling fluid. Thereby, the cooling tubes may be connected to a cooling aggregate.

The heating means, cooling means, and/or cables are preferably located in the folded core structure. Preferably, the heating means, cooling means, and/or cables are located in the void volumes in the relaxed honeycomb structure or in channels provided in the folded core structure.

Channels in the folded core structure can be provided, at least in a half-closed honeycomb structure, by comprising rows of honeycomb cells having a smaller height compared to honeycomb cells having a larger height next to the honeycomb cells having the smaller height. By having rows of honeycomb cells having a smaller height than the honeycomb cells having a larger height next to the honeycomb cells having a smaller height, a channel is established, in which heating means, cooling means, and/or cables can be introduced.

In a preferred embodiment, the folded core structure comprises a first main surface and a second main surface and comprises a skin layer on at least one of the main surfaces of the folded core structure. The skin layer on at least one of the main surfaces of the folded core structure may further improve the dimensional stability and/or rigidity of the flooring composite, which is particularly advantageous when the flooring composite is a carpet tile. The skin layer can restrict movement of the half cell walls without requiring providing an additional adhesive or welding to ensure that the cell halves are firmly fixated to each other to provide rigidity.

The first main surface and the second main surface of the folded core structure are preferably parallel to each other, wherein the first main surface of the folded core structure is on the side of the folded core structure facing the flooring surface and the second main surface of the folded core structure is on the side of the folded core structure facing away from the flooring surface.

The skin layer can be bonded to the folded core structure chemically, thermally and/or mechanically. Thereby, the skin layer on at least one of the main surfaces of the folded core structure can improve the dimensional stability at least in the plane of the skin layer, i.e. in machine direction and cross machine direction. It is also possible that the skin layer also improves the dimensional stability in z- direction as due to the bonded skin layer, the folded core structure is fixed in its folding.

The skin layer can be a two-dimensional (2D) layer and may consists of a material selected from a group comprising a woven, a nonwoven such as a spunbonded or spun laid nonwoven, a melt blown nonwoven, a carded nonwoven, a needle- punched nonwoven, an air laid nonwoven, a hydroentangled nonwoven, and a wet laid nonwoven, a knitted fabric, a net, a scrim, a two-dimensional mat of extruded entangled filaments, a consolidated layer of unidirectional fibers, a continuous film, a discontinuous film, a paper, or any combination thereof.

Within the scope of the invention, the term “nonwoven” has to be understood as according to the EDANA (European Disposables and Nonwovens Association) and ISO 9092: A nonwoven is an engineered fibrous assembly, primarily planar, which has been given a designed level of structural integrity by physical and/or chemical means, excluding weaving, knitting or paper making. The continuous film and/or the discontinuous films can be provided by coating e.g. a thermoplastic polymeric material and/or a thermoplastic elastomeric polymeric material.

The woven, nonwovens, scrims, nets, unidirectional fibers or knitted fabric of the skin layer may comprise mineral fibers, such as for example glass, basalt or rockwool fibers, and/or fibers composed of thermoplastic polymeric material or thermoplastic elastomeric polymeric material.

The fibers may have any cross-sectional shape, including round, trilobal, multi-- lobal or rectangular, the latter exhibiting a width and a height wherein the width may be considerably larger than the height, so that the fiber in this embodiment is a tape.

Preferably, the fibers comprised in the skin layer are composed of a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material.

The fibers comprised in the skin layer can be monofilaments, multifilament yarns, mono-component fibers, two types of mono-component fibers and/or multicomponent fibers, in particular bicomponent fibers. The bicomponent fibers may be of a side-by-side model, concentric or eccentric core/sheath model or islands-in-the-sea model.

In an embodiment, the mono-component fibers comprised in the skin layer comprise of a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material.

Preferably, the mono-component fibers comprised in the skin layer are composed of a thermoplastic polymer selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

In a preferred embodiment, the fibers comprised in the skin layer are bicomponent fibers of the core/sheath model. Preferably, the core and the sheath of the bicomponent fibers comprised in the skin layer comprise a thermoplastic polymer and/or a thermoplastic elastomeric polymer.

By using bicomponent fibers comprising thermoplastic polymers and/or thermoplastic elastomeric polymers, the bicomponent fibers can combine the properties of a certain tensile strength of the core of the bicomponent fibers as well as a certain bonding strength between the fibers. This is possible if the thermoplastic polymeric material or thermoplastic elastomeric polymeric material of the sheath has a lower melting temperature than the core. Thus, the sheath can be at least partially melted, such that bicomponent fibers can be adhered together by the sheath and comprising at the same time the non-deteriorated properties of the core.

For the core and the sheath of the bicomponent fibers comprised in the skin layer, any suitable thermoplastic polymer and/or thermoplastic elastomeric polymer can be used. Preferably, the polymer of the sheath has a melting temperature which is lower than the melting temperature of the polymer of the core.

In an embodiment, the core of the bicomponent fibers comprises a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material.

Preferably, the core of the bicomponent fibers is composed of a thermoplastic polymeric material selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

In an embodiment, the sheath of the bicomponent fibers comprises a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material.

Preferably, the sheath of the bicomponent fibers is composed of a thermoplastic polymeric material selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

In an embodiment, the fibers comprised in the skin layer are filaments or staple fibers. Preferably, the fibers comprised in the skin layer are filaments.

In the case, the fibers comprised in the skin layer are filaments, the dimensional stability of the textile fabric, at least in plane of the skin layer is improved due to the fact that forces affecting on the skin layer can be distributed along the whole length of the filaments and thus over an enlarged area of the skin layer. Preferably, the fibers comprised in the skin layer of the skin layer are bonded at their crossing points. This will improve the aforementioned effect. The bonding of the fibers comprised in the skin layer can be chemical bonding, mechanical bonding and/or thermal bonding. Preferably, the bonding of the fibers comprised in the skin layer is a chemical bonding and/or thermal bonding.

In a preferred embodiment, the skin layer comprises monofilaments, multifilament yarns, mono-component fibers, two types of mono-component fibers and/or multicomponent fibers, in particular bicomponent fibers.

In the case, the skin layer comprises two-types of mono-component fibers, one type of the two-types of mono-component fibers can be for stability reasons and the other type for bonding reasons.

In a preferred embodiment, the flooring surface is a carpet such as a tufted carpet, woven carpet or needlefelt carpet, a laminate, LVT laminate, natural flooring such as cork or wood, PVC flooring, and/or ceramic tiles.

In a further preferred embodiment, the flooring surface comprises a primary carpet backing, and tufting yarns tufted into the primary backing.

The flooring surface comprising a primary carpet backing and tufting yarns tufted into the primary backing can be used directly, without any further layers, in the flooring composite.

Preferably, the tufting yarns are cut pile yarns and/or loop pile yarns.

Preferably, the primary carpet backing comprises at least a textile fabric. The textile fabric may comprise fibers and is preferably a woven, a knitted fabric, a nonwoven such as a spun-laid nonwoven, a carded nonwoven, a needle-punched nonwoven, an air-laid nonwoven, a hydroentangled nonwoven, and a wet-laid nonwoven, a melt blown nonwoven, a layer of unidirectional fibers, a net, a scrim, a two-dimensional entangled mat of extruded filaments, or any combination thereof.

Within the scope of the invention, the term “spun-laid nonwoven”, has to be understood that the nonwoven is manufactured by extruding the fibers from a spinneret and subsequently laying down on a conveyor belt as a web of filaments and subsequently bonding the web to form a nonwoven layer of fibers, or by a two- step process wherein filaments are spun and wound on bobbins, preferably in the form of multifilament yarns, followed by the steps of unwinding the multifilament yarns and laying the filaments down on a conveyor belt as a web of filaments and bonding the web to form a nonwoven layer of fibers.

The fibers may have any cross-sectional shape, including round, trilobal, multi- lobal or rectangular, the latter exhibiting a width and a height wherein the width may be considerably larger than the height, so that the fiber in this embodiment is a tape.

In the textile fabric of the primary carpet backing, the fibers of the textile fabric can be filaments or staple fibers. Preferably, the fibers of the textile fabric of the primary carpet backing are filaments.

In the case, the fibers of the textile fabric of the primary carpet backing are filaments, the dimensional stability of the textile fabric, at least in plane of the textile fabric is improved due to the fact that forces affecting on the textile fabric can be distributed along the whole length of the filaments and thus over an enlarged area of the textile fabric. Preferably, the fibers comprised in the textile fabric of the primary carpet backing are bonded at their crossing points. This will further improve the dimensional stability of the textile fabric. The bonding of the fibers the textile fabric of the primary carpet backing can be chemical bonding, mechanical bonding and/or thermal bonding. Preferably, the bonding of the fibers the textile fabric of the primary carpet backing is a chemical bonding and/or thermal bonding.

In a preferred embodiment, the textile fabric of the primary carpet backing comprises monofilaments, multifilament yarns, mono-component fibers, two types of mono-component fibers and/or multicomponent fibers, in particular bicomponent fibers.

In the case, the textile fabric of the primary carpet backing comprises two-types of mono-component fibers, one type of the two types of mono-component fibers can be for stability reasons and the other type for bonding reasons.

In a further preferred embodiment, the fibers of the textile fabric of the primary carpet backing comprise a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

In another preferred embodiment, a precoat and/or a polymer coat can be added, preferably between the flooring back surface and the folded core structure, to the flooring surface comprises a primary carpet backing, and tufting yarns tufted into the primary backing. The precoat and/or the polymer coat may have the advantage that the tufting yarns tufted into the primary carpet backing are fixated. Further, the precoat and/or polymer coat may be used as a bonding agent to bond the tufted primary carpet backing onto the folded core structure.

In another preferred embodiment, the flooring surface comprises a secondary carpet backing, preferably between the primary carpet backing and the folded core structure.

By adding a secondary carpet backing to the flooring surface the dimensional stability of the flooring surface can be improved and/or the secondary carpet backing can be used as a bonding layer which bonds the tufted primary carpet backing onto the folded core structure. It is believed that at the same time the secondary backing can improve the tuft lock of the tufting yarns in the primary carpet backing by bonding the tufting yarns.

Preferably, the secondary carpet backing comprises at least a textile fabric. The textile fabric may comprise fibers and is preferably a woven, a knitted fabric, a nonwoven such as a spun-laid nonwoven, a carded nonwoven, a needle-punched nonwoven, an air-laid nonwoven, a hydroentangled nonwoven, and a wet-laid nonwoven, a melt blown nonwoven, a layer of unidirectional fibers, a net, a scrim, a two-dimensional entangled mat of extruded filaments, or any combination thereof.

The fibers may have any cross-sectional shape, including round, trilobal, multi- lobal or rectangular, the latter exhibiting a width and a height wherein the width may be considerably larger than the height, so that the fiber in this embodiment is a tape. In the textile fabric of the secondary carpet backing, the fibers of the textile fabric can be filaments or staple fibers. Preferably, the fibers of the textile fabric of the secondary carpet backing are filaments.

In the case, the fibers of the textile fabric of the secondary carpet backing are filaments, the dimensional stability of the textile fabric, at least in plane of the textile fabric is improved due to the fact that forces affecting on the textile fabric can be distributed along the whole length of the filaments and thus over an enlarged area of the textile fabric. Preferably, the fibers comprised in the textile fabric of the secondary carpet backing are bonded at their crossing points. This will improve the aforementioned effect.

The bonding of the fibers the textile fabric of the secondary carpet backing can be chemical bonding, mechanical bonding and/or thermal bonding. Preferably, the bonding of the fibers the textile fabric of the secondary carpet backing is a chemical bonding and/or thermal bonding.

In a preferred embodiment, the textile fabric of the secondary carpet backing comprises monofilaments, multifilament yarns, mono-component fibers, two types of mono-component fibers and/or multicomponent fibers, in particular bicomponent fibers.

In the case, the textile fabric of the secondary carpet backing comprises two-types of mono-component fibers, one type of the two types of mono-component fibers can be for stability reasons and the other type for bonding reasons and/or shaping capability.

In a further preferred embodiment, the fibers of the textile fabric of the secondary carpet backing comprise a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

The flooring composite may comprise at least one additional layer on the second main surface of the folded core structure.

In a preferred embodiment, the at least one additional layer can be a two- dimensional (2D) layer and may consist of a material selected from a group comprising a woven, a nonwoven such as a spunbonded or spun laid nonwoven, a melt blown nonwoven, a carded nonwoven, a needle-punched nonwoven, an air laid nonwoven, a hydroentangled nonwoven, and a wet laid nonwoven, a knitted fabric, a net, a scrim, a two-dimensional mat of extruded entangled filaments, a consolidated layer of unidirectional fibers, a continuous film, a discontinuous film, or a combination thereof. Preferably, the at least one additional layer is a carded nonwoven.

Without being bound to theory, it is believed that a carded nonwoven used as additional layer improves the acoustic properties of the flooring composite.

The at least one additional layer may also be a three-dimensional (3D) layer and may consist of a material selected from a group comprising a three-dimensional nonwoven, a foam, a three-dimensional structured mat of extruded filaments, a further folded core structure, knitted spacer fabrics, woven spacer fabrics, corrugated sheets, dimple drain materials, a ridged surface material or a combination thereof. The three-dimensional nonwoven can be provided from a two-dimensional nonwoven by three-dimensional shaping the nonwoven by e.g. thermoforming. The thermoforming can be performed by heated profiled rolls. In the case the nonwoven comprises bicomponent fibers, such as core sheath type bicomponent fibers, and the nonwoven is thermoformed by heated profiled rolls, the sheath of the bicomponent fiber, which is melted by the heated rolls, is responsible for retaining the three-dimensional shape. An Example of such a three-dimensional nonwoven is disclosed by EP 1620254 B1

The fibers may have any cross-sectional shape, including round, trilobal, multi- lobal or rectangular, the latter exhibiting a width and a height wherein the width may be considerably larger than the height, so that the fiber in this embodiment is a tape.

Preferably, the filaments of the three-dimensional structured mat of extruded entangled filaments are extruded polymeric filaments. A three-dimensional structured mat of extruded entangled filaments may be provided by any suitable process. Preferably, the three-dimensional structured mat of extruded entangled filaments is provided by extruding polymeric filaments and collecting the extruded filaments into a three-dimensional structure by allowing the filaments to bend, to entangle and to come into contact with each other, preferably in a still molten state. Bending and entangling of the extruded filaments are preferably initiated by collecting the filaments onto a profiled surface, which defines the structure of the three-dimensional structured mat of extruded entangled filaments. Preferably, the surface on which the filaments are collected is profiled such that the three- dimensional structured mat of filaments is shaped into a three-dimensional form which comprises hills and valleys, hemispheres, positive and/or negative cuspates, cups and/or waffles, pyramids, U-grooves, V-grooves, cones and/or cylinders capped with a hemisphere. In another preferred embodiment, the at least one additional layer is laminate of at least one three-dimensional layer and at least one two-dimensional layer.

In a preferred embodiment, all parts of the flooring composite, e.g. the folded core structure, the flooring surface comprising tufting yarns tufted into the primary carpet backing, the secondary carpet backing and the at least one additional layer, comprise a thermoplastic polymer or a thermoplastic elastomeric polymer. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2- furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

All parts of the flooring composite can be composed of different polymers, but preferably all parts of the flooring composite are composed of one thermoplastic polymer or one thermoplastic elastomeric polymer or of a single polymer family. Preferably, at least the primary carpet backing, the secondary carpet backing, the tufting yarns and/or the skin layer comprised in the flooring composite are composed of one thermoplastic polymer or one thermoplastic elastomeric polymer or of a single polymer family.

Within the scope of the invention, a polymer family has to be understood that the polymers of one family are composed of at least 50 % of the same monomeric units.

Preferably, all parts of the flooring composite are composed of thermoplastic polymers or thermoplastic elastomeric polymers, which are constituted of at least 50 %, preferably of at least 60 %, more preferably of at least 70 %, even more preferably of at least 80 %, even more preferably of at least 90 %, even more preferably of at least 95 %, and most preferably of 100 % of the same monomeric units.

In the case, all parts of the flooring composite are constituted of the same of thermoplastic polymeric material or thermoplastic elastomeric polymeric material or of the same family of thermoplastic polymeric material or thermoplastic elastomeric polymeric material, the flooring composite can be easily recycled after its lifetime.

In another preferred embodiment, the at least one additional layer is an underfloor heating and/or a drainage layer.

The object is also solved by a method of manufacturing a flooring composite by providing a folded core structure and a flooring surface located adjacent to a flooring back surface of the flooring surface, characterized in that the said folded core structure is formed from an uncut flat body, by plastic deformation perpendicular to the plane of the uncut flat body such that three-dimensional structures comprising half cell walls and connection areas are formed, wherein the half cell walls are at an angle a to each other to provide a relaxed honeycomb structure or adjoin one another in the form of a honeycomb cell to provide a half- closed honeycomb structure, wherein the adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls.

Preferably, the method comprises the step of pushing the three-dimensional structures towards each other at predefined folding lines to form the relaxed honeycomb structure or the half-closed honeycomb structure.

The aforementioned embodiments regarding the flooring composite are also applicable to the method of manufacturing the flooring composite. The object of the present invention is also solved by a carpet tile comprising the flooring composite according to any of the aforementioned embodiments.

Preferably, the folded core structure comprised in the carpet tile is a half-closed honeycomb structure.

Without being bound to theory, it is believed that comprising a half-closed honeycomb structure as folded core structure in the carpet tile, improves the dimensional stability of the carpet tile, at least in machine direction and cross machine direction of the comprised folded core structure. Thereby, the carpet tile also exhibits an improved bending stiffness, which will increase the flatness i.e. avoidance of dishing and doming of a flooring, and shear and dynamic loads. Further, it is believed that due to the half-closed honeycomb structure, the compression strength of the folded core structure is improved, such that the carpet tile is able to carry large weight loads, which can occur by using the carpet tile as flooring. As the half cell walls are at an angle a to each other to provide a relaxed honeycomb structure, or adjoin one another in the form of a honeycomb cell to provide a half-closed honeycomb structure, wherein the adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls, the flooring composite can be rolled up.

The method of manufacturing the flooring composite enables to manufacture the half closed honeycomb structure or the relaxed honeycomb structure efficiently as compared to the folding-type honeycomb structure of JP 2013220648 A, as the method of manufacturing the flooring composite does not require an additional adhesive or welding to ensure that the cell halves are firmly fixated to each other.

A folded core structure, comprised in a carpet tile, could comprise adjoining cell walls of neighboring half cell walls, which are bonded to each other (e.g. Fig. 1 , 104a-d). In the case, the adjoining cell walls would be bonded together, the folded core structure, respectively the carpet tile comprising the folded core structure would have an excellent dimensional stability as the folded core structure is fixed in its fully folded state. Thus, the folded core structure is not able or at least the ability is reduced to be stretched or compressed in any direction, and the resistance against shear forces would be improved.

The adjoining cell walls of neighboring half cell walls could be bonded thermally, chemically, and/or mechanically. The bonding could be a chemical bonding and/or a thermal bonding. However, a folded core structure wherein the half cell walls are bonded to each other, e.g. over the full surfaces of the adjoining cell walls, requires more complex processing as compared to the folded core structure comprised in the flooring composite. Furthermore, a folded core structure wherein the half cell walls are bonded to each other, e.g. over the full surfaces of the adjoining cell walls, do not enable that the flooring composite can be rolled up.

In a further preferred embodiment, the carpet tile comprises connecting means such that at least two carpet tiles can be mechanically connected to each other.

Such connecting means can be any suitable connecting means such as a nut and bold connecting assembly or any kind of form-fit connection. Form-fit connections are commonly known and are used e.g. for click laminate. Thereby, a first part of a form-fit connection, which may comprise a projection (male part), and is custom-fit to a second part of a form-fit connection, which may comprise an indentation (female part). Both parts of a form-fit connection can be put together to build up a connection between, e.g. two carpet tiles, and can be easily released. This connection and disconnection can be performed multiple times, such that a carpet tile comprising such connecting means can be used at different locations several times without loss of dimensional stability and having at the same time a very easy handling. Preferably, the connecting means comprise a thermoplastic polymeric material or a thermoplastic elastomeric polymeric material. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

The connecting means can be attached additionally to the carpet tile and bonded to the carpet tile by any suitable bonding technique. Preferably, the connecting means are provided from the thermoplastic polymeric material or thermoplastic elastomeric polymeric material of the carpet tile. Thereby, the connecting means can be provided from the thermoplastic polymeric material or thermoplastic elastomeric polymeric material of the carpet tile by a thermoforming process.

In a preferred embodiment, all parts of the carpet tile, e.g. the folded core structure, the flooring surface comprising tufting yarns tufted into the primary carpet backing, the secondary carpet backing, the at least one additional layer and the connecting means, comprise a thermoplastic polymer or a thermoplastic elastomeric polymer. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2-furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof. All parts of the carpet tile can be composed of different polymers, preferably all parts of the carpet tile are composed of one thermoplastic polymeric material or one thermoplastic elastomeric polymeric material or all parts of the carpet tile are composed of polymers of the same polymer family. Preferably, at least the primary carpet backing, the secondary carpet backing, the tufting yarns and/or the skin layer comprised in the carpet tile are composed of one thermoplastic polymer or one thermoplastic elastomeric polymer or of a single polymer family.

Preferably, all parts of the carpet tile are composed of thermoplastic polymeric material or thermoplastic elastomeric polymeric material, which comprise of at least 50 %, preferably of at least 60 %, more preferably of at least 70 %, even more preferably of at least 80 %, even more preferably of at least 90 %, even more preferably of at least 95 %, and most preferably of 100 % of the same monomeric units.

In the case, all parts of the carpet tile are composed of one thermoplastic polymeric material or one thermoplastic elastomeric polymeric material or all parts of the carpet tile are composed of polymers of the same polymer family, the carpet tile can be easily recycled after its lifetime.

The object can also be solved by a broadloom carpet comprising the flooring composite according to any of the aforementioned embodiments.

In a preferred embodiment, the broadloom carpet comprises folded core structure, which is a relaxed honeycomb structure or a half-closed honeycomb structure, in which adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls. Thereby, the relaxed honeycomb structure or half-closed honeycomb structure, in which adjoining cell walls of neighboring half cell walls are free of bonding to each other at the main surfaces of the cell walls, provide a certain degree of flexibility such that the broadloom carpet can be rolled up and is easily transportable. Preferably, the broadloom carpet comprises a folded core structure which is a relaxed honeycomb structure.

In a preferred embodiment, all parts of the broadloom carpet, e.g. the folded core structure, the flooring surface comprising tufting yarns tufted into the primary carpet backing, the secondary carpet backing and the at least one additional layer, comprise a thermoplastic polymer or a thermoplastic elastomeric polymer. Preferably, the thermoplastic polymeric material is selected from a group consisting of polyolefins, in particular polyethylene (PE) or polypropylene (PP), polyesters, in particular polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT) or polyetylene-1 ,2- furandicaboxylate (PEF), polyamides, in particular polyamide 6 (PA6) or polyamide 6,6 (PA6,6), polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyvinyl butyral (PVB), polycarbonate (PC), polyether, polyetheresters, copolymers and mixtures thereof.

All parts of the broadloom carpet can be composed of different polymers, preferably all parts of the broadloom carpet are composed of one thermoplastic polymeric material or one thermoplastic elastomeric polymeric material or all parts of the carpet tile are composed of polymers of the same polymer family.

Preferably, at least the primary carpet backing, the secondary carpet backing, the tufting yarns and/or the skin layer comprised in the broadloom carpet are composed of one thermoplastic polymer or one thermoplastic elastomeric polymer or of a single polymer family.

Preferably, all parts of the broadloom carpet are composed of thermoplastic polymers or thermoplastic elastomeric polymers, which comprise of at least 50 %, preferably of at least 60 %, more preferably of at least 70 %, even more preferably of at least 80 %, even more preferably of at least 90 %, even more preferably of at least 95 %, and most preferably of 100 % of the same monomeric units. In the case, all parts of the broadloom carpet are composed of one thermoplastic polymeric material or one thermoplastic elastomeric polymeric material or all parts of the carpet tile are composed of polymers of the same polymer family, the broadloom carpet can be easily recycled after its lifetime.

The object is also solved by an artificial turf comprising a flooring composite according to any of the aforementioned embodiments.

The flooring composite, respectively the carpet tile, the broadloom carpet and/or the artificial turf comprising such a flooring composite can be used in flat applications such as flooring, but also in non-flat application such as staircase covering or molded application such as interior of automotive, trains, aircrafts.

Figure 1 : Schematic cross section of a flooring composite Figure 2: Schematic cross section of a flooring composite Figure 3: Schematic perspective view of a part of a relaxed honeycomb structure

Figure 4: Schematic cross-sectional view of a relaxed honeycomb structure. Figure 5: Schematic top view of a honeycomb cell. Figure 6: Schematic perspective view of a part of a honeycomb cell of a relaxed honeycomb structure.

Figure 7 Schematic cross-sectional view of a fully folded honeycomb cell of a honeycomb structure.

Figure 1 shows a part of a cross section of a flooring composite 100 comprising a flooring surface 101 with tufting yarns 101a tufted into the primary carpet backing 101b and a folded core structure 102. The folded core structure 102 is a half- closed honeycomb structure comprising honeycomb cells 103, which are delimited by cell walls. Thereby, the half-closed honeycomb structure 102 has neighboring honeycomb cells which have adjoining cell walls 104a and 104b which are in contact to each other. 104a and 104b indicates these adjoining cell walls for a first row of honeycomb cells, the dashed lines indicated by 104c and 104d shows adjoining cell walls of a neighboring row of honeycomb cells in cross machine direction. Further, the honeycomb cells 103 of the half-closed honeycomb structure 102 comprises on one side of each honeycomb cell a connection area 105a or 105b, which closes the honeycomb cells on one side either on the side facing the flooring surface 101 or on the side facing away from the flooring surface 101. Thereby, the connection area 105a is the connection area for the first row of honeycomb cells, which is on the side of the half-closed honeycomb structure 102 facing the flooring surface 101 , and the connection area 105b is the connection area of the neighboring row of honeycomb cells in cross machine direction, which is on the side of the half-closed honeycomb structure 102 facing away from the flooring surface 101.

Figure 2 shows a part of a cross section of a flooring composite 200 comprising a flooring surface 201 with tufting yarns 201a tufted into the primary carpet backing 201b and a folded core structure 202. The folded core structure is a relaxed honeycomb structure, wherein the folding of the plastically deformed uncut flat body is stopped before two half cells 203 meet together. Thereby, the relaxed honeycomb structure 202 is preferably in contact with the flooring surface 201 by the edges 203a, and preferably in contact with the ground (or optionally with any further layer; both not shown) by the edges 203b.

Figure 3 shows a part of a relaxed honeycomb structure 300 half cells 306 having a height h and a half diameter dhaif. Also, the relaxed honeycomb structure 300 comprises kinks 307 and connection areas 305a. The machine direction MD and cross machine direction CD are indicated by arrows.

Figure 4 shows a cross sectional view of a relaxed honeycomb structure 402, which has an angle a between two in machine direction consecutive half cells 409 and 410. Thereby, the two half honeycomb cells are folded such that an angle a is established by the corner points 408a-c and 408d-f. The machine direction MD and cross machine direction CD are indicated by arrows.

Figure 5 shows a schematic top view of a honeycomb cell 500. In this honeycomb cell 500 the diameter d is the perpendicular distance between two parts 511a of two consecutive half cell walls of the honeycomb structure in machine direction, which are oriented parallel to each other. The machine direction MD and cross machine direction CD are indicated by arrows.

Figure 6 shows a schematic perspective view of a part of a honeycomb cell of a relaxed honeycomb structure 600 comprising a kink 607 and a cell wall of the half cells of the relaxed honeycomb structure 611 , which is oriented parallel to the kink 607. The diameter of the honeycomb cells of the relaxed honeycomb structure is determined by measuring the diameter dhaif between the kink 607 and the cell wall of the half-cell of the relaxed honeycomb structure 611 , which is perpendicular to the kink 607 and perpendicular to the plane of the cell wall 611 , and sum up the diameters dhaif of two half cells, which share the same kink 607. The partially dashed lines 612 indicates a half-cell of the relaxed honeycomb structure. The machine direction MD and cross machine direction CD are indicated by arrows.

Figure 7 shows a schematic cross-sectional view of a fully folded honeycomb cell of a honeycomb structure 700 comprising a connection area 705 and honeycomb cell walls 711. The height of the fully folded honeycomb cell 700 is measured as the perpendicular distance between the plane of connection area 705 and the end of the honeycomb walls 711. The machine direction MD and cross machine direction CD are indicated by arrows.