NL2027270B1 - Decorative panel and decorative floor covering consisting of said panels - Google Patents

Abstract

The invention relates to a panel, in particular a decorative panel, a floor panel, a ceiling panel or a wall panel. The invention also relates to a covering consisting of a plurality of mutually coupled panels according to the invention, in particular a floor covering consisting of a plurality of mutually coupled panels, according to the invenflon.

Description

Decorative panel and decorative floor covering consisting of said panels The invention relates to a panel, in particular a decorative panel, a floor panel, a ceiling panel or a wall panel.

The invention also relates to a covering consisting of a plurality of mutually coupled panels according to the invention, in particular a floor covering consisting of a plurality of mutually coupled panels, according to the invention.

In the field of decorative floor coverings, decorative panels are known having a

MDF {Medium Density Board) or HDF (High Density Board) based core layer on top of which a decorative substrate is attached to provide the panels a desired appearance.

A major disadvantage of these known panels is the hygroscopic nature of the core layer, which affects the lifetime and durability of such panels.

For this reason, the traditional MDF/HDF based panels are more and more replaced by polyvinyl chloride (PVC) based panels, also provided with a decorative substrate on top.

These PVC based panels have the advantage over of being relatively waterproof compared to MDF/HDF based panels.

The PVC based panels are typically enriched with chalk (calcium carbonate), acting as inert filler, wherein the applied amount of chalk has been increased in the course of time, in particular to reduce the cost price of the panels.

These panels are also referred to as stone- plastic composite (SPC) panels.

A first drawback, however, of these PVC based panels is that the temperature resistance is very poor, as a result of which these panels will typically easily deform (curve) in case these panels are exposed to a heating source, like a heating radiator or even a lamp.

Moreover, a common additional important drawback of both the MDF/HDF based panels and the PVC based panels is the flammability of these panels.

Flammability of furniture is of concern as, for example, cigarettes and candle accidents can easily trigger domestic fires.

Additionally, the trend to use more chalk in the PVC based panels seriously increases the brittleness of the panels, which consequently increases the risk of breakage of the panels.

In particular, in case the panels are profiled to allow adjacent panels to interlock with each other, the risk of breakage of the coupling profiles of the panels prior to use and during use has been increased seriously, which often renders these panels less or even not suitable anymore to compose a so-called floating floor covering consisting of interlocked panels.

Hence, there is a general need in the field of decorative flooring to further develop decorative panels to counteract at least one of the above drawbacks, and in particular to develop a decorative panel which is relatively fireproof.

There is an additional need to develop a decorative panel having an improved dimensional stability when subjected to temperature fluctuations during regular use.

There is a further need to develop an interlockable panel which can be profiled relatively smoothly, preferably in dependent of the hardness of a decorative top layer of the panel, and wherein the coupling profiles exhibit a reduced risk of breakage.

It is an objective of the invention to meet at least one of the needs addressed above.

The above objective of the invention, is met by the provision of a decorative panel, in particular a floor panel, ceiling panel or wall panel, comprising: a core provided with an upper side and a lower side, a decorative top structure affixed, either directly or indirectly, on said upper side of the core, a first panel edge comprising a first coupling profile, and a second panel edge comprising a second coupling profile being designed to engage interlockingly with said first coupling profile of an adjacent panel, both in horizontal direction and in vertical direction, wherein said core comprises at least one wool layer at least partially formed by vitreous fibres bonded together by at least one cured thermoset polymeric binder material.

Typically, the wool layer comprises (man-made) vitreous wool, also referred to as mineral wool composed of (man-made) vitreous fibres (MMVF) bonded together.

This type of mineral fibre product are typically made by converting a melt made of suitable raw materials to fibres in conventional manner, for instance by a spinning cup process or by a cascade rotor process.

The fibres or threads are blown into a forming chamber and, while airborne and while still hot, are sprayed with a binder solution and randomly deposited as a mat or web onto a travelling conveyor.

The fibre mat is then transferred to a curing oven where heated air is blown through the mat to cure the binder and rigidly bond the mineral fibres together.

Preferably, at least a fraction of the man-made vitreous fibres (MMVF) are made of at least one material selected from the group consisting of mineral wool and/or mineral fibres, including stone wool, mineral wool, slag wool, basalt wool, dolomite wool, diabase wool, volcanic wool, ceramic fibres, and glass fibres.

The stone or (volcanic) rock based ingredients can be obtained directly from nature.

Slag wool is typically made from recycled waste product of a blast furnace.

Glass wool is typically made from a mixture of natural and recycled glass, for example obtained from recycled bottles, car windscreens and window panes.

The mineral wools are non-combustible, thermally stable, and moisture-resistant.

It retains its properties even in humid conditions.

Moreover, sound can be efficiently blocked by mineral wool, which makes mineral wool as a relatively good sound dampening material, which is a beneficial property its use in floor, wall, and ceiling panels.

Moreover, it has surprisingly been found that these minerals wools, bonded by a cured thermosetting binder, can be profiled in a very smooth manner which makes this material suitable to have at least a part of each coupling profile integrally formed by the material(s) of the core, in particular at least one wool layer of the core.

Due to the non-brittle, tough material properties of said wool layer(s), the risk of damaging the coupling profiles during or after manufacturing can be kept to a minimum, which makes the panel according to the invention ideally suitable to compose, in a durable and reliable manner, a floating floor covering consisting of interlocked panels according to the invention.

This is a great advantage over today’s SPC panels.

The core may also be referred to as a substrate of the panel.

The (mineral) wool layer is also referred to as (mineral) wool mat or (mineral) wool web, and is typically a three-dimensional layer having a thickness of at least 2 mm,

preferably a thickness of between 2 and 12 mm, more preferably a thickness of between 3 and 10 mm.

In this layer vitreous fibres may have an at least partially vertical orientation and/or may be stacked on top of each other.

Preferably, in at least one wool layer the amount (in weight percent) of vitreous fibres exceeds the amount (in weight percent) of cured thermoset polymeric binder material.

Preferably, in at least one wool layer the amount of vitreous fibres is between 75 and 95 percent by weight, more preferably between 80 and 90 percent by weight.

Preferably, in at least one wool layer the amount of binder material is between 5 and 20 percent by weight, more preferably between 10 and 17 percent by weight.

The wool layer may comprise traces of other materials and/or may comprises one or more additives, like colorants and/or fillers.

Addition of the binder is preferably carried out under conditions that allow the binder to be uniformly distributed over the vitreous fibres.

In particular, it is preferred to prevent the formation of fibre bundles, this binder or these binders being dispersed within non-bonded fibres that are liable to easily break and thereby generate dust. This operation aims at retaining fibres that are bonded together by junction points that are sufficiently strong to ensure good cohesion and to ensure that the product does not tear when used. However, the cohesion is preferably not too high, so that the bonding remains flexible and the final product retains a certain deformability. In particular, the junctions between the fibres must provide a network that is stable and rigid enough to withstand the compression imposed by storing and transporting the product and during its normal use as (floor) panel. Normally, the binder is supplied very close to the fibre-forming device. The reason for applying the binder to the suspended fibres, and not to the mat already formed on the receiving conveyor is that it is difficult to have the binder penetrate into a mineral wool mat since such mats are tight and the fibres have a fine structure compared to the size of the binder drops.

Curing of the mineral fibre web (mineral wool) may be carried out in a curing oven by introducing a hot-air stream into the mineral fibre web. However, at the entrance of the curing oven where the uncured and thus soft mineral fibre web is introduced into the oven, there often occurs the problem that the hot-air stream may be of a magnitude that holes or depressions are formed in the mineral fibre web (so-called "hollow-blowing"), which is undesired since these holes or depressions may be visible in the final panel. As curing takes place along the length of the curing oven, the problem decreases in importance because the stiffness increases and the web gains resistance against the air pressure. The curing quality may be improved by applying one or more co-binders having e.g. a lower T-onset temperature (temperature at which the curing starts) than the T-onset temperature of a main binder, strength is fast built up in the mineral fibre web upon introduction into the curing oven, thereby reducing the risk of the occurrence of hollow-blowing in the non-cured or partly cured sections and improving curing quality and curing rate. Preferably, the core, in particular at least one wool layer, comprises a mixture of binder materials, wherein a first binder material has a higher curing temperature and/or curing rate than at least one second binder material. This allows to use air pressures that would normally cause hollow-blowing which, in turn, increases production capacity. The thermosetting binder material(s) used in the core, in particular in the (mineral) wool layer, may comprise both formaldehyde-containing and formaldehyde-free, organic and inorganic binder resins. Suitable formaldehyde-containing resins are, for instance, phenoplast-type resins (phenol- formaldehyde resins or urea-modified phenol-formaldehyde resins) and aminoplast- type resins (melamine-formaldehyde resins or urea-formaldehyde resins), or combinations thereof. Preferred examples of formaldehyde-free binder materials 5 are described below. Preferably, this binder material comprises the (water-soluble) reaction product of an alkanolamine with a carboxylic anhydride obtainable by reacting at least one alkanolamine with at least one carboxylic anhydride and, optionally, treating the reaction product with a base. Preferred alkanolamines for use in the preparation of this binder materials are alkanolamines having at least two hydroxy groups. Specific examples of suitable alkanolamines are diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, methyldiethanolamine, ethyldiethanolamine, n-butyldiethanolamine, methyldiisopropanolamine, ethylisopropanolamine, ethyldiisopropanolamine, 3-amino-1,2-propanediol, 2- amino-1,3-propanediol and tristhydroxymethyl)aminomethane. Diethanolamine is the currently preferred alkanolamine. The carboxylic anhydride reactant may be selected from saturated or unsaturated aliphatic and cycloaliphatic anhydrides, aromatic anhydrides and mixtures thereof, saturated or unsaturated cycloaliphatic anhydrides, aromatic anhydrides and mixtures thereof being preferred. In a particularly preferred embodiment of the invention, two different anhydrides selected from cycloaliphatic and/or aromatic anhydrides are employed. Other suitable examples of binder materials, which may in particular be used as co-binder are acrylic resin and an epoxy resin. Preferably, the amount of co-binder, based on solids, is 1 to 50 weight percent of the total binder, preferably 5 to 35 weight percent of the total binder.

Preferably, at least one binder material is formed by a sugar component, preferably selected from the group consisting of: sucrose, reducing sugars in particular dextrose, polycarbohydrates, and mixtures thereof. Glucose, also known as dextrose, is formed in plants from carbon dioxide absorbed from the air using sunlight as energy source. Part of the glucose is polymerised into long chains of glucose and stored as starch in granules as a reserve. The viscosity and the content of large polymers in a sugar syrup generally may decrease with an increasing DE value. DE is an abbreviation for Dextrose Equivalent and is defined as the content of reducing sugars, expressed as the number of grams of anhydrous D-glucose per 100 g of the dry matter in the sample, when determined by the method specified in International Standard ISO 5377-1981 (E). Hydrolytic cleavage of the starch may be stopped at different stages of the process resulting in carbohydrate mixtures (sugar syrups) having different DE numbers, i.e. having different molecular weight distribution and different reactivity.

Only glucose syrup of high DE can crystallise easily and yield a product in powder or granular form.

A most popular crystallised product is dextrose monohydrate with application in medicine and chewing tablets.

Dextrose monohydrate is pure glucose (DE 100). A large content of polymers should preferably be avoided for a mineral wool binder material because this will provide a more sticky binder resulting in stickiness of the formed mineral wool layer (wool mat or binder-containing web) to the manufacturing equipment such as e.g. the forming chamber walls, the travelling conveyors, rollers and pendulums.

The solubility of the binder solution containing a sugar syrup may increase with increasing DE value.

The binder solution must be sufficiently water soluble to provide a homogenous distribution of the binder on the mineral fibres making up the mineral wool mat or web to be cured.

Preferably, the binder material comprises an aqueous binder composition comprising a sugar syrup containing a reducing sugar having a dextrose equivalent DE of 50 to less than 85. This will typically provide excellent products fulfilling the many demands to the binder in a mineral wool production line and the demands to the products obtained by using the binder. insufficient curing may also occur throughout the whole wool layer.

This may e.g. be the case where the production line has a production change from one product type to another and where the curing settings needs to be changed.

For example,

changing from a low binder content product to a high binder content product, or vice versa.

During the run-in of the line, the curing settings may not be optimal and insufficient curing occurs.

Another problem that may occur during the production of mineral fibre products are anomalies of the binder distribution like the agglomeration of large amounts of binder material in a single part of the wool layer,

which affects the properties and is therefore undesired.

The curing process can be monitored more closely by adding at least one fluorescent compound to the core, in particular to the wool layer, more in particular to the binder material of the wool layer.

Quenching of the fluorescence by the binder material is influenced by the curing.

For the purpose of the present invention, the term "cured or partly cured binding material " refers to a binder which has at least been cured to a certain degree, e.g. by thermally treating in a curing apparatus, but has not necessarily been treated to achieve full curing in all regions of the product. By visual inspection, the presence or absence and/or pattern of fluorescence on the surface of the wool layer and/or a colour change can be detected. In this way, irregularities in curing or anomalies of the binder material can therefore immediately be detected and the production process can therefore be re-adjusted quickly, thereby minimizing the wastage of inadequate wool layers. While in principal, any of the fluorescent compounds can be used in any amount in the panel, in particular the core, more in particular the wool layer according to the present invention, particularly good results have been achieved when the liquid mixture comprises a fluorescent compound selected from the group consisting of one or more xanthenes, such as fluorescein sodium salt, 2',7'-dichlorofluorescein, rhodamine B, rhodamine 6G, eosin Y disodium salt (2',4',5',7',-tetrabromofluorescein disodium salt), sulforhodamine B; one or more acridines, such as acridine orange (3,6-bis(dimethylamino)acridine), acridine yellow G (3,6-diamino-2,7-dimethylacridine hydrochloride); quinine and/or one or more quinine derivatives, such as in form of a quinine containing tonic water; one or more coumarins, such as umbelliferone (7-hydroxycoumarin); one or more arylsulfonates, such as pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt). Experiments have shown that well-cured areas (brownish) as well as binder free areas (white) appeared "as usual" in daylight and were nonfluorescent under 365 nm UV light. Areas with uncured binder were easily detected - and distinguished from binder free areas - under 365 nm UV light by the presence of pink-orange fluorescence and under daylight by the presence of pink coloration: the presence of uncured binder as a result of for example shot nests were detected.

Even small uncured spots not visible to the naked eye in daylight were efficiently detected under 365 nm UV light. Preferably, the core, in particular at least one wool layer, comprises aerogel particles. Aerogel is a synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas without significant collapse of the gel structure, resulting in a solid with extremely low density, and with a beneficial vapor permeability. More preferably, the weight of aerogel particles in the core exceeds the weight of the binder material and/or the weight of the man-made vitreous fibres in the core. Hence, preferably a relatively large weight (and amount) of aerogel particles is used, which could significantly reduce the weight and density of the core, and hence of the panel as such. This results in the use of less binder material, which is favourable from a cost point of view. The aerogel particles are kept entrapped in a vitreous fibre "cage", where the fibres are connected by the binder material at junctions between fibres. Thereby the aerogel particles are kept inside the wool layer.

During production the orientation of the fibres in the wool layer(s) can be adjusted. For one of the intended uses of the panel, in particular as floor panel, it is favourable in case at least one wool layer comprises fibres, wherein the fibre orientation is substantially vertical and/or in a vertical-chaotic manner. Here, the vertical component of the fibre orientation is dominant over the horizontal component of the fibre orientation. This will increase the compression strength of the wool layer. This does not exclude that it is imaginable that the fibre orientation in at least one wool layer of the core could be substantially horizontal. It is imaginable that the core comprises at least one base wool layer comprising a first mineral wool, and at least one top wool layer, positioned on top of said base wool layer, comprising a second mineral wool. The first and second mineral wool may be the same. However, preferably the first wool and the second wool have different material compositions and/or different structural properties, such as different fibre orientations. In general when terms like "horizontal" and "vertical" or similar directional references are used in the present disclosure, these terms are meant to be understood as relative terms e.g. where the term "vertical" refers to a direction perpendicular to the plane defined by the panel and "horizontal" refers to a direction coinciding with or parallel to said plane of the panel. Preferably, the panel, in particular the core, more in particular at least one wool layer, comprises at least one reinforcement layer, preferably a non-woven layer or woven layer, in particular a cloth. Each reinforcement layer preferably has a thickness of 0.2 — 0.4 mm. It is conceivable that the core has a multi-layer structure, wherein at least one reinforcing layer is enclosed in between two other layers of the panel, in particular of the core. Preferably, the density of the reinforcing layer is situated between 1.000 and 2.000 kg/m3, preferably between 1.400- and 1.900 kg/m3, and more preferably between 1.400 and 1.700 kg/m3. The reinforcement layer may comprise natural fibers, such as but not limited to jute, and/or may comprise synthetic fibres, such as polymer fibres, in particular nylon fibres; glass fibres; or carbon fibres. It is imaginable that at least one reinforcement layer is embedded in at least one wool layer and, preferably in between two wool layers stacked on top of each other. lt is imaginable that the panel comprises a plurality of reinforcement layers, wherein, preferably, at least one first reinforcement layer is located in a top portion of the core, and wherein at least one second reinforcement layer is located in a bottom portion of the core.

Preferably, at least one core, in particular at least one wool layer, has a density lower than 1.200 kg/m3. In case aerogel particles are applied, a relatively low density of approximately 80-100 kg/m3 could be obtained. Typically, the density is situated between 130 and 1.050 kg/m3. Preferably, at least one core, in particular at least one wool layer, has an area density lower than 12 kg/m2, preferably lower than 10 kg/m2.

Preferably, the coefficient of thermal expansion coefficient of the panel, preferably the core, more preferably at least one wool layer, in at least one direction is below 0,03 mm/m/10°C, preferably below 0,02 mm/m/10°C. This thermal expansion coefficient preferably applies both to the longitudinal direction and to the transversal direction of the panel, preferably the core, more preferably at least one wool layer. Preferably, the Young's modulus of at least one wool layer is situated between 3,500 and 5,200 MPa, more preferably between 4,000 and 4,500 MPa. The Flexural strength of at least one wool layer is preferably situated between 40 and 50 MPa, more preferably between 43 and 48 MPa.

Preferably, the decorative top structure is adhered onto the core by means of an adhesive, in particular a waterproof adhesive. This prevents that the top structure easily delaminates from the core upon wettening. An example of a suitable adhesive is a polyurethane adhesive.

Preferably, an adhesive is used which loses its adhesion at a predetermined temperature, more preferably an adhesive which loses its adhesion between 80 and 120 degrees Celsius. Such adhesive would allow to separate the core and the top structure such that both parts can be recycled separately. In addition, the use of such adhesive allows an exchange of a damaged top structure by (locally) heating the panel, typically to a temperature between 80 and 120 degrees Celsius, such that the top layer can be exchanged without having to remove multiple panels. Preferably, the adhesive layer is a flexible layer configured to withstand (linear) expansion and contraction differences between the core and the top structure. Preferably, a hot melt adhesive (thermoplastic adhesive) is used. The invention also relates to the use of an adhesive, in particular a hot melt adhesive, which loses its adhesion at least partially and/or has a reduced bond strength, at an elevated temperature, preferably between 80 and 120 degrees Celsius, for gluing a decorative top structure, either directly of indirectly, onto the core to construct a decorative panel, in particular a decorative panel according to the invention. Such an adhesive facilitates delamination of the panel for recycling purposes.

Some of the possible base materials of suitable adhesives include the following: Ethylene-vinyl acetate (EVA) copolymers, which typically leads to a low- performance, low-cost hot melt adhesive. They provide sufficient strength between 15 and 50 °C but are limited to use below 60-80 °C and have low creep resistance under load. The vinyl acetate monomer content is preferably about 18-29 percent by weight of the polymer. High amounts of tackifiers and waxes are often used; an example composition is 30-40% of EVA copolymer (provides strength and toughness), 30-40% of tackifier resin (improves wetting and tack), 20-30% of wax (usually paraffin-based; reduces viscosity, alters setting speed, reduces cost), and

0.5-1.0% of stabilizers. Fillers can be added Lower molecular weight chains provide lower melt viscosity, better wetting, and better adhesion to porous surfaces.

Higher molecular weight chains provide better cohesion at elevated temperatures and better low-temperature behaviour. Increased ratio of vinyl acetate lowers the crystallinity of the material, improves optical clarity, flexibility and toughness, and worsens resistance to solvents. EVA can be crosslinked by, e.g., peroxides, yielding a thermosetting material. EVAs can be compounded with aromatic hydrocarbon resins. Grafting butadiene to EVA improves its adhesion. lts dielectric properties are poor due to high content of polar groups, the dielectric loss is moderately high, which renders this material less preferable in case well-insulated floor panels would be needed, . EVAs are optically clearer and more gas and vapor permeable than polyolefins;

0 Ethylene-acrylate copolymers have lower glass transition temperature and higher adhesion even to difficult substrates, compared to EVA. These copolymers exhibit a better thermal resistance, increased adhesion to metals and glass, compared to EVA. Suitable for low temperature use. Ethylene-vinylacetate-maleic anhydride and ethylene-acrylate-maleic anhydride terpolymers offer very high performance. Examples are ethylene n-butyl acrylate (EnBA), ethylene-acrylic acid (EAA) and ethylene-ethyl acetate (EEA).

. Polyolefins (PO) (polyethylene (usually LDPE but also HDPE, which has a higher melting point and better temperature resistance), atactic polypropylene (PP or APP), polybutene-1, oxidized polyethylene, etc.), low-performance, for difficult- to-bond plastics. Very good adhesion to polypropylene, good moisture barrier, chemical resistance against polar solvents and solutions of acids, bases, and alcohols. Longer open time in comparison with EVA and polyamides. Polyolefins have low surface energy and provide good wetting of most metals and polymers.

Metallocene-catalyst-synthesised polyolefins have a narrow distribution of molecular weight and correspondingly narrow melting temperature range. Due to the relatively high crystallinity, polyethylene-based glues tend to be opaque and, depending on additives, white or yellowish. Polyethylene hot melts have high pot life stability, are not prone to charring, and are suitable for moderate temperature ranges and on porous non-flexible substrates. Nitrogen or carbon dioxide can be introduced into the melt, forming a foam which increases spreading and open time and decreases transfer of heat to the substrate, allowing use of more heat-sensitive substrates; polyethylene-based HMAs are usually used. PE and APP are usually used on their own or with just a small amount of tackifiers (usually hydrocarbons) and waxes (usually paraffins or microcrystalline waxes, for lower cost, improved anti-blocking, and altered open time and softening temperature). The molecular weight of the polymer is usually lower. Lower molecular weights provide better low- temperature performance and higher flexibility, higher molecular weights increase the seal strength, hot tack, and melt viscosity.

o Polybutene-1 and its copolymers are soft and flexible, tough, partially crystalline, and slowly crystallizing with long open times. The low temperature of recrystallization allows for stress release during formation of the bond. Good bonding to nonpolar surfaces, worse bonding to polar ones. Good for rubber substrates, and can be formulated as pressure-sensitive.

0 Amorphous polyolefin (APO/APAO) polymers are compatible with many solvents, tackifiers, waxes, and polymers; they find wide use in many adhesive applications. APO hot melts have good fuel and acid resistance, moderate heat resistance, are tacky, soft and flexible, have good adhesion and longer open times than crystalline polyolefins. APOs tend to have lower melt viscosity, better adhesion, longer open times and slow set times than comparable EVAs. Some APOs can be used alone, but often they are compounded with tackifiers, waxes, and plasticizers (e.g., mineral oil, poly-butene oil). Examples of APOs include amorphous (atactic) propylene (APP), amorphous propylene/ethylene (APE), amorphous propylene/butene (APB), amorphous propylene/hexene (APH), amorphous propylene/ethylene/butene. APP is harder than APE, which is harder than APB, which is harder than APH, in accordance with decreasing crystallinity. APOs show relatively low cohesion, the entangled polymer chains have fairly high degree of freedom of movement. Under mechanical load, most of the strain is dissipated by elongation and disentanglement of polymer chains, and only a small fraction reaches the adhesive-substrate interface. Cohesive failure is therefore a more common failure mode of APOs.

. Polyamides and polyesters, high-performance 0 Polyamides (PA), high-performance, for severe environments; high- temperature glues; typically applied at over 200 °C, but can degrade and char during processing. In molten state can somewhat degrade by atmospheric oxygen. High application temperature. High range of service temperatures, generally showing adequate bonding from —40 to 70 °C; some compositions allow operation to 185 °C if they do not have to carry load. Resistant to plasticizers, therefore suitable for gluing polyvinyl chloride; only polyamides derived from secondary diamines however provide a satisfying bond. Resistant to oils and gasoline. Good adhesion to many substrates such as metal, wood, vinyl, ABS, and treated polyethylene and polypropylene. Three groups are employed, with low, intermediate, and high molecular weight; the low molecular weight ones are low- temperature melting and easy to apply, but have lower tensile strength, lower tensile-shear strength, and lower elongation than the high molecular weight ones. The high molecular weight ones require sophisticated extruders and are used as high-performance structural adhesives. The presence of hydrogen bonds between the polymer chains gives polyamides a high strength at even low molecular weights, in comparison with other polymers. Hydrogen bonds also provide retention of most of the adhesive strength up almost to the melting point; however they also make the material more susceptible to permeation of moisture in comparison with polyesters. Can be formulated as soft and tacky or as hard and rigid. Niche applications, together with polyesters taking less than 10% of total volume of hot melt adhesives market. Absorption of moisture may lead to foaming during application as water evaporates during melting, leaving voids in the adhesive layer which degrade mechanical strength. Polyamide HMAs are usually composed of a dimer acid with often two or more different diamines. The dimer acid usually presents 60-80% of the total polyamide mass, and provides amorphous nonpolar character. Linear aliphatic amines such as ethylene diamine and hexamethylene diamine, provide hardness and strength. Longer chain amines such as dimer amine, reduce the amount of hydrogen bonds per volume of material, resulting in lower stiffness. Polyether diamines provide good low-temperature flexibility. Piperazine and similar diamines also reduce the number of hydrogen bonds. Only polyamides based on piperazine and similar secondary amines form satisfactory bond with polyvinyl chloride; primary amines form stronger hydrogen bonds within the adhesive, secondary amines can act only as proton acceptors, don't form hydrogen bonds within the polyamide, and are therefore free to form weaker bonds with vinyl, probably with the hydrogen atom adjacent to the chlorine.

o Polyesters, similar to the ones used for synthetic fibers. High application temperature. Synthetized from a diol and a dicarboxylic acid. The length of the diol chain has major influence to the material's properties; with increasing diol chain length the melting point increases, the crystallization rate increases, and the degree of crystallization decreases. Both the diol and acid influence the melting point. In comparison with similar polyamides, due to absence of hydrogen bonds, polyesters have lower strength and melting point, but are much more resistant to moisture, though still susceptible. In other parameters, and in applications where these factors do not play a role, polyesters and polyamides are very similar. Polyesters are suitable for bonding fabrics. They can be used on their own, or blended with large amounts of additives. They are used where high tensile strength and high temperature resistance are needed. Most polyester hot melt adhesives have high degree of crystallinity. Polyesters are often highly crystalline, leading to narrow melting temperature range, which is advantageous for high-speed bonding.

. Polyurethanes

0 Thermoplastic polyurethane (TPU) offer good adhesion to different surfaces due to presence of polar groups. Their low glass transition temperature provides flexibility at low temperatures. They are highly elastic and soft, with wide possible crystallization and melting point ranges. Polyurethanes consist of long linear chains with flexible, soft segments (diisocyanate-coupled low-melting polyester or polyether chains) alternating with rigid segments (diurethane bridges resulting from diisocyanate reacting with a small-molecule glycol chain extender). The rigid segments form hydrogen bonds with rigid segments of other molecules. Higher ratio of soft to hard segments provides better flexibility, elongation, and low- temperature performance, but also lower hardness, modulus, and abrasion resistance. The bonding temperature is lower than with most other HMAs, only about 50-70 °C, when the adhesive behaves as a soft rubber acting as a pressure- sensitive adhesive. The surface wetting in this amorphous state is good, and on cooling the polymer crystallizes, forming a strong flexible bond with high cohesion.

Choice of a proper diisocyanate and polyol combination allows tailoring the polyurethane properties; they can be used on their own or blended with a plasticizer. Polyurethanes are compatible with most common plasticizers, and many resins.

0 Polyurethanes (PUR), or reactive urethanes, for high temperatures and high flexibility. Solidification can be rapid or extended in range of several minutes; secondary curing with atmospheric or substrate moisture then continues for several hours, forming cross-links in the polymer. Excellent resistance to solvents and chemicals. Low application temperature, suitable for heat-sensitive substrates. Heat-resistant after curing, with service temperatures generally from —30 °C to +150 °C. Ink-solvent resistant. Usually based on prepolymers made of polyols and methylene diphenyl! diisocyanate (MDI) or other diisocyanate, with small amount of free isocyanate groups; these groups when subjected to moisture react and cross- fink. The uncured solidified "green" strength tends to be low than non-reactive HMAs, mechanical strength develops with curing. Green strength can be improved by blending the prepolymer with other polymers. Since PUR is highly flexible and has a broad thermal setting range, PUR is perfect for bonding difficult substrates.

. Styrene block copolymers (SBC), also called styrene copolymer adhesives and rubber-based adhesives, have good low-temperature flexibility, high elongation, and high heat resistance. Frequently used in pressure-sensitive adhesive applications, where the composition retains tack even when solidified;

however non-pressure-sensitive formulations are also used.

High heat resistance, good low-temperature flexibility.

Lower strength than polyesters.

They usually have A-B-A structure, with an elastic rubber segment between two rigid plastic endblocks.

High-strength film formers as standalone, increase cohesion and viscosity as an additive.

Water-resistant, soluble in some organic solvents; cross- linking improves solvent resistance.

Resins associating with endblocks (cumarone- indene, a-methyl styrene, vinyl toluene, aromatic hydrocarbons, etc.) improve adhesion and alter viscosity.

Resins associating to the midblocks (aliphatic olefins, rosin esters, polyterpenes, terpene phenolics) improve adhesion, processing and pressure-sensitive properties.

Addition of plasticizers reduces cost, improves pressure-sensitive tack, decrease melt viscosity, decrease hardness, and improve low-temperature flexibility.

The A-B-A structure promotes a phase separation of the polymer, binding together the endblocks, with the central elastic parts acting as cross-links; SBCs do not require additional cross-linking. o Styrene-butadiene-styrene (SBS), used in high-strength PSA (pressure- sensitive adhesive) applications. 0 Styrene-isoprene-styrene (SIS), used in low-viscosity high-tack PSA applications. 0 Styrene-ethylene/butylene-styrene (SEBS), used in low self-adhering non- woven applications. 0 Styrene-ethylene/propylene (SEP) . Polycaprolactone with soy protein, using coconut oil as plasticizer, a biodegradable hot-melt adhesive . Polycarbonates = Fluoropolymers, with tackifiers and ethylene copolymer with polar groups . Silicone rubbers, undergo cross-linking after solidification, form durable flexible UV and weather resistant silicone sealant . Thermoplastic elastomers . Polypyrrole (PPY), a conductive polymer, for intrinsically conducting hot melt adhesives (ICHMAs), used for EMI shielding.

EVA compounded with 0.1-0.5 wt.% PPY are strongly absorbing in near infrared, allowing use as near-infrared activated adhesives. . various other copolymers.

The adhesive may be enriched with one or more additives. Examples of such additives include the following: . tackifying resins (e.g., rosins and their derivates, terpenes and modified terpenes, aliphatic, cycloaliphatic and aromatic resins (C5 aliphatic resins, C9 aromatic resins, and C5/C9 aliphatic/aromatic resins), hydrogenated hydrocarbon resins, and their mixtures, terpene-phenol resins (TPR, used often with EVAs)), up to about 40%. Tackifiers tend to have low molecular weight, and glass transition and softening temperature above room temperature, providing them with suitable viscoelastic properties. Tackifiers frequently present most of both weight percentage and cost of the hot-melt adhesive.

. waxes, e.g., microcrystalline waxes, fatty amide waxes or oxidized Fischer- Tropsch waxes; increase the setting rate. One of the key components of formulations, waxes lower the melt viscosity and can improve bond strength and temperature resistance.

« plasticizers (e.g., benzoates such as 1,4-cyclohexane dimethanol dibenzoate, glyceryl tribenzoate, or pentaerythritol tetrabenzoate, phthalates, paraffin oils, polyisobutylene, chlorinated paraffins, etc.) . antioxidants and stabilizers (e.g., hindered phenols, BHT, phosphites, phosphates, hindered aromatic amines); added in small amounts (<1%)}, not influencing physical properties. These compounds protect the material from degradation both during service life, compounding and in molten state during application. Stabilizers based on functionalized silicones have improved resistance to extraction and outgassing.

. UV stabilizers protect the material against degradation by ultraviolet radiation . pigments and dyes, glitter . biocides for hindering bacterial growth . flame retardants . antistatic agents = fillers, for reducing cost, adding bulk, improving cohesive strength (forming an aggregate-matrix composite material) and altering properties; e.g., calcium carbonate, barium sulfate, talc, silica, carbon black, clays (e.g., kaolin).

Fugitive glues and pressure-sensitive adhesives are available in hot-melt form. With a tack-like consistency, PSA are bonded through the application of pressure at room temperature. Additives and polymers containing unsaturated bonds are highly prone to autoxidation. Examples include rosin-based additives. Antioxidants can be used for suppressing this aging mechanism. Addition of ferromagnetic particles, hygroscopic water-retaining materials, or other materials can yield a hot melt adhesive which can be activated by microwave heating. Addition of electrically conductive particles can yield conductive hot-melt formulations.

In another preferred embodiment, the decorative top structure is fused onto the core, preferably without using a separate adhesive. This may, for example, be realized by using a thermoplastic layer or film as bottom layer of the decorative top structure, which may be heated and subsequently fused or welded to the core. Alternatively or additionally, this may, for example, also be realized by applying a core having a softenable upper surface, in particular by applying a core comprising a thermoplastic top layer; and/or by having a top side of the core formed by an at least partially uncured wool layer, wherein at least a part of the top structure is applied onto said uncured top side of the core, after which the core is cured by means of (ir)radiation, such as heat and/or UV radiation. In case the top structure is provided with a cureable layer, such as an (UV) hardenable lacquer layer, it is imaginable that during production a single curing step is applied to cure both the core and the top structure.

It is (also) conceivable that the lower side of the decorative top structure penetrates into an upper side of the core and/or that the upper side of the core penetrates into a lower side of the decorative top structure, preferably over a depth greater than

0.1 millimetre. In case the decorative top structure penetrates into an upper side of the core, this can be realized, for example, by applying a decorative top structure comprising as bottom layer a thermoplastic layer and/or a primer layer and/or an adhesive layer. In particular in case of an adhesive layer, the adhesive is typically applied in liquid state, a certain penetration and (further) reinforcement of the core, in particular of at least one wool layer, and/or of one or more further layers of the decorative top structure can be achieved. A penetration and reinforcement of the core by a penetrated part of the decorative top structure is in particular advantageous at the lateral edge(s) of the core, in particular at the lateral edge(s) at which a groove or recess is applied. According to this embodiment, also an improved laminating strength between the core and the decorative top structure can be achieved. In this case, the risk of tearing between the core and the top structure, or splitting, can be reduced.

The decorative top structure preferably penetrates the upper side of the core (and/or vice versa) on the entire interface formed between the core and the decorative top structure or on at least 50 percent of said interface.

The achieved penetration depth preferably is greater than 1 percent of the thickness of the core.

In case a multi-layer core is used, the achieved penetration depth preferably is greater than 10 percent of the thickness of an upper layer of the core. lt was found that a panel according to the embodiment typically exhibits an (highly) increased impact resistance of the panel as such, which is in particular favourable for the decorative top structure and the coupling profiles of the panel.

Moreover, with a panel according to this embodiment it is possible to improve the impact resistance of the panel without the necessity to add further rigid or resilient reinforcing elements like a rubber layer, a fiberglass layer, or metal plates.

In fact, by applying at least two partially overlapping (interlacing or interweaving) layers of the panel, in particular by allowing at least one layer to penetrate into another layer, the transmission and dissipation of the impact stress through the panel can be improved significantly so that a lower portion of said energy is absorbed by the decorative layer improving the impact resistance thereof.

Since it is not necessary to add rigid reinforcing elements, the resulting panel can be made lighter and thinner.

Moreover, the penetration of one layer into at least one other layer, the propagation of cracks in the core and/or the decorative top structure could be hindered.

Furthermore, in case of superficial cracks of the core and/or decorative top structure, the partially penetrated, bonding layer, such as an adhesive layer could keep the core and the decorative layer itself coherent, and preferably compacted, thereby disguising the visual appearance of the superficial cracks.

The decorative top structure preferably has a thickness between 0.5 to 12 millimeters, preferably between 1 and 6 millimeters, more preferably between 2 and 4 millimeters.

It is experimentally found that the core can provide sufficient support for any top layer when having a thickness between 0.5 and 12 millimeters.

The decorative top structure can be of various nature.

The top structure may be a single layer or a multi-layer top structure, wherein at least one layer of the top structure is formed by a slab and/or a tile and/or other (thinner or thicker) layer, in particular a coating or a veneer layer.

In a preferred embodiment, the top layer is at least partially made of a glaze and/or ceramic and/or stone, and/or any material chosen from the group consisting of: polymer, linoleum, ceramic, stone, concrete, mineral porcelain, glass, quartz, soapstone, mosaic, granite, limestone and marble.

These materials may be solid or may be porous at least to some extent.

In case a glaze is applied, this glaze may be transparent or semi-transparent.

Typically, said glaze is a ceramic glaze, which is an impervious layer or coating of a vitreous substance which has been fused to a ceramic body through firing.

This glaze can be coloured and/or have a decorative character, and is typically waterproof.

Raw materials of ceramic glazes generally include silica, which will be the main glass former.

Various metal oxides, such as sodium, potassium, and calcium, may act as flux and therefore lower the melting temperature.

Alumina, often derived from clay, is preferably used to stiffen the molten glaze to prevent it from running off the piece.

Colorants, such as iron oxide, copper carbonate, or cobalt carbonate, and sometimes opacifiers like tin oxide or zirconium oxide, are used to modify the visual appearance of the fired glaze.

In case at least one layer of the top structure is at least partially made of a polymer, this can be a soft polymer, such as rubber or any other (soft) thermoplastic or thermosetting polymer; or a harder polymer, such as ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) or any other (harder) thermoplastic or thermosetting polymer.

Linoleum, commonly shortened to lino, is a polymer based composite comprising solidified linseed oil (linoxyn), and pine resin, and preferably wood dust, such as ground cork dust and/or sawdust, and optionally mineral fillers such as calcium carbonate.

The slab and/or a tile and/or other (thinner or thicker) layer, in particular a coating or a veneer layer, of the top structure, may be glued and/or fused to another layer of the top structure and/or to the core.

Here, it is conceivable that a tile, slab, coating, glaze, or veneer layer is glued onto the core by using an (intermediate) adhesive layer.

This adhesive layer may considered as making part of the decorative top structure.

Alternatively, it is conceivable that a tile, slab, coating, glaze, or veneer layer is fused (directly) onto the core, e.g. by firing and/or heating and/or curing a laminate of the core and the decorative top structure.

Hence, it is imaginable that the panel according to the invention consist of two layers: a core formed by a single wool layer (provided with coupling profiles); and a single decorative top layer fused onto said core. ft is imaginable that a footprint of the core exceeds a footprint of the decorative top structure.

It is imaginable that the a part of the upper side of the core, preferably along one or more edges, extends with respect to the decorative top structure. This exposed part of the upper side of the core may be used to facilitate coupling of panels and/or to form a grout line, optionally to be filled with grout after installation (interlocking) of the panels.

The decorative top structure may also be a multi-layered structure. Preferably, the decorative top structure comprises at least one decorative layer and at least one transparent wear layer covering said decorative layer. Preferably, the decorative top structure comprises from bottom to top: i. Optionally, at least one base layer, in particular a primer and/or adhesive layer, ii. Atleast one décor layer, in particular a thermoplastic or paper film provided with a decorative (digital or mechanically applied) print, ii. Atleast one transparent wear layer covering said decorative layer, and iv. Optionally, at least one lacquer layer, preferably UV cured lacquer layer, covering said wear layer. Said lacquer layer or other protective layer may be applied on top of said wear layer to protect the top structure and hence the panel as such. A finishing layer may be applied in between the decorative layer and the wear layer. The decorative layer will be visible and will be used to provide the panel an attractive appearance. To this end, the decorative layer may have a design pattern, which can, for example be a wood grain design, a mineral grain design that resembles marble, granite or any other natural stone grain, an image, a photo, or a colour pattern, colour blend or single colour to name just a few design possibilities. Customized appearances, often realized by digital printing during the panel production process, are also imaginable. In an alternative embodiment, the decorative top structure is omitted, thus not applied, in the panel according to the invention. In this latter embodiment, the decorative panel, in particular a floor panel, ceiling panel or wall panel, comprising: a core provided with an upper side and a lower side, a first panel edge comprising a first coupling profile, and a second panel edge comprising a second coupling profile being designed to engage interlockingly with said first coupling profile of an adjacent panel, both in horizontal direction and in vertical direction, wherein said core comprises at least one wool layer at least partially formed by man-made vitreous fibres bonded together by at least one cured thermoset polymeric binder material.

Preferably, the first coupling profile comprises: . an upward tongue, . at least one upward flank lying at a distance from the upward tongue, an upward groove formed in between the upward tongue and the upward flank wherein the upward groove is adapted to receive at least a part of a downward tongue of a second coupling profile of an adjacent panel, and . at least one first locking element, preferably provided at a distant side of the upward tongue facing away from the upward flank, and preferably the (complimentary) second coupling profile comprises: . a first downward tongue, . at least one first downward flank lying at a distance from the downward tongue, . a first downward groove formed in between the downward tongue and the downward flank, wherein the downward groove is adapted to receive at least a part of an upward tongue of a first coupling profile of an adjacent panel, and . at least one second locking element adapted for co-action with a first locking element of an adjacent panel, said second locking element preferably being provided at the downward flank.

Preferably, the first locking element comprises a bulge and/or a recess, and wherein the second locking element comprises a bulge and/or a recess. The bulge is commonly adapted to be at least partially received in the recess of an adjacent coupled panel for the purpose of realizing a locked coupling, preferably a vertically locked coupling. It is also conceivable that the first locking element and the second locking are not formed by a bulge-recess combination, but by another combination of co-acting profiled surfaces and/or high-friction contact surfaces. In this latter embodiment, the at least one locking element of the first locking element and second locking element may be formed by a (flat of otherwise shaped) contact surface composed of a, optionally separate, plastic material configured to generate friction with the other locking element of another panel in engaged (coupled) condition. Examples of plastics suitable to generate friction include: - Acetal (POM), being rigid and strong with good creep resistance. It has a low coefficient of friction, remains stable at high temperatures, and offers good resistance to hot water;

- Nylon (PA), which absorbs more moisture than most polymers, wherein the impact strength and general energy absorbing qualities actually improve as it absorbs moisture. Nylons also have a low coefficient of friction, good electrical properties, and good chemical resistance; - Polyphthalamide (PPA). This high performance nylon has through improved temperature resistance and lower moisture absorption. It also has good chemical resistance; - Polyetheretherketone (PEEK), being a high temperature thermoplastic with good chemical and flame resistance combined with high strength. PEEK is a favourite in the aerospace industry; - Polyphenylene sulphide (PPS), offering a balance of properties including chemical and high-temperature resistance, flame retardance, flowability, dimensional stability, and good electrical properties; - Polybutylene terephthalate (PBT), which is dimensionally stable and has high heat and chemical resistance with good electrical properties; - Thermoplastic polyimide (TPI) being inherently flame retardant with good physical, chemical, and wear-resistance properties. - Polycarbonate (PC), having good impact strength, high heat resistance, and good dimensional stability. PC also has good electrical properties and is stable in water and mineral or organic acids; and - Polyetherimide (PEI), maintaining strength and rigidity at elevated temperatures. It also has good long-term heat resistance, dimensional stability, inherent flame retardance, and resistance to hydrocarbons, alcohols, and halogenated solvents.

it is imaginable that the first coupling profile and the second coupling profile are configured such that in coupled condition a pretension is existing, which forces coupled panels at the respective edges towards each other, wherein this preferably is performed by applying overlapping contours of the first coupling profile and the second coupling profile, in particular overlapping contours of downward tongue and the upward groove and/or overlapping contours of the upward tongue and the downward groove, and wherein the first coupling profile and the second coupling profile are configured such that the two of such panels can be coupled to each other by means of a fold-down movement and/or a vertical movement, such that, in coupled condition, wherein, in coupled condition, at least a part of the downward tongue of the second coupling part is inserted in the upward groove of the first coupling part, such that the downward tongue is clamped by the first coupling part and/or the upward tongue is clamped by the second coupling part.

In a preferred embodiment, the panel comprises at least one third coupling profile and at least one fourth coupling profile located respectively at a third panel edge and a fourth panel edge, wherein the third coupling profile comprises: . a sideward tongue extending in a direction substantially parallel to the upper side of the core, « at least one second downward flank lying at a distance from the sideward tongue, and . a second downward groove formed between the sideward tongue and the second downward flank, wherein the fourth coupling profile comprises: « a third groove configured for accommodating at least a part of the sideward tongue of the third coupling profile of an adjacent panel, said third groove being defined by an upper lip and a lower lip, wherein said lower lip is provided with an upward locking element, wherein the third coupling profile and the fourth coupling profile are configured such that two of such panels can be coupled to each other by means of a turning movement, wherein, in coupled condition: at least a part of the sideward tongue of a first panel is inserted into the third groove of an adjacent, second panel, and wherein at least a part of the upward locking element of said second panel is inserted into the second downward groove of said first panel.

The panel, typically the core, in particular at least one core, preferably comprises recycled material. Recycled material typically relates to reusing left-over material resulting from prior (panel) production processes.

The core preferably has a thickness of at least 3 mm, preferably at least 4 mm, and still more preferably at least 5 mm. The panel thickness is typically situated in between 3 and 12 mm, preferably in between 4 and 10 mm.

In a preferred embodiment, at least one wool layer has a varying density in the thickness direction of said wool layer. Preferably, the ratio mineral fibres and binder material varies in the thickness direction. In this manner, the more dense or less dense sublayer may be formed at the top side and/or bottom side of the wool layer, dependent on the desired properties of the panel. It is imaginable that at least one wool layer has a varying density in a width direction and/or a length direction of said wool layer. This may, for example, lead to a more dense wool layer zone at two or more panel's edges, which could be favourable for the formation of coupling profiles at these edges. It is imaginable that at least one wool layer is at least partially filled with at least one filler, in particular an inert filler. This filler may for example be a colourant, chalk, talc, an antimicrobial substance, a fluorescent dye, etcetera. In a preferred embodiment, the panel comprises at least one backing layer, which is affixed, either directly or indirectly, to a lower side of the core. At least one backing layer is preferably at least partially made of a flexible material, preferably at least one material chosen from the group consisting of: an elastomer, a thermoplastic material, ethylene-vinyl acetate, polyurethane, cork, wood, paper, and cardboard. The thickness of the backing layer typically varies from about 0.1 to

2.5 mm. The backing layer commonly provides additional robustness, dimensional stability, and an improved impact resistance of the panel as such, which increases the durability of the panel and prevent damaging of the panel. Moreover, the (flexible) backing layer may increase the acoustic (sound-dampening) properties of the panel. The invention also relates to a core for use in a decorative panel according to one of the previous claims, wherein a first core edge comprises at least a part of the first coupling profile, and wherein a second core edge comprises at least a part of the second coupling profile being designed to engage interlockingly, both in horizontal direction and in vertical direction, with said first coupling profile of an adjacent panel or adjacent core, wherein said core comprises at least one wool layer at least partially formed by man-made vitreous fibres bonded together by at least one cured thermoset polymeric binder material. The invention further relates to a decorative covering, in particular a decorative floor covering, decorative ceiling covering, or decorative wall covering, comprising a plurality of mutually coupled decorative panels according to the invention.

The invention will be elucidated on the basis of non-limitative exemplary embodiments shown in the following figures, wherein: Fig. 1 shows a rectangular floor panel according to the present invention; Fig. 2 shows a transversal cross-section along line A-A in fig. 1, of respective side edges; Fig. 3 shows a method of coupling of the side edges shown in fig. 2; Fig. 4 shows in a transversal cross-section, the side edges of fig. 2 in coupled condition; Fig. 5 shows a longitudinal cross-section along line B-B in fig. 1 of respective side edges; Fig. 6 shows a method of coupling of the side edges shown in fig. 5; Fig. 7 shows in a longitudinal cross-section, further details of respective side edges when in coupled condition; Fig. 8 shows an alternative embodiment of the side edges of fig. 2 which allow for another method of coupling; Fig. 9 shows another alternative embodiment of the side edges of fig. 2.

Fig. 1 shows a decorative panel 1 which upper side 2 is provided with a decorative top structure 12 (see also figure 2). The panel is of a rectangular shape having a length extending longitudinally along line B-B, and a width extending transversally along line A-A. The plane of the panel is hence determined by the combination of lines A-A and B-B. At opposite side edges 3 and 4, a first coupling part in the form of profile 5, resp. a second coupling part in the form of profile 6 is provided. At opposite side edges 9 and 10, a third coupling part in the form of profile 7 resp. a fourth coupling part in the form of profile 8 is provided.

Fig. 2 shows in transversal cross-section the first coupling part 5 at side edge 3.

The first coupling part 5 comprises a sideward tongue 20 which comprises a front region 21 and a back region 22, wherein a bottom surface 23 and/or a side surface 23 of said front region 21 is rounded at least partly, wherein a top surface 24 of the front region 21 is at least partially inclined downwardly in a direction away from the back region 22, and wherein a bottom surface 26 and/or side surface 26 of the back region 22 of said sideward tongue 20 defines a first contact portion 26, and wherein the sideward tongue 20 comprises a passive bottom surface 27 situated adjacent to the first contact portion 26, wherein said passive bottom surface 27 is defined by a cut-out portion at a lower side of the sideward tongue 20. The passive bottom surface 27 herein extends over an intermediate region 28 between the back region 22 and the front region 21, and is substantially flat.

The passive bottom surface 27 is inclined downwardly in a direction towards the front region 21, such that the inclined top surface 24 of the sideward tongue and the inclined passive bottom surface 27 converge in a direction away from the back region of the sideward tongue.

Furthermore, the second coupling part 6 comprises a recess 30 for accommodating at least a part of the sideward tongue 20 of a further panel, said recess 30 being defined by an upper lip 31 and a lower lip 32, wherein the lower lip 32 extends beyond the upper lip 31, and wherein the lower lip 32 is provided with a upwardly protruding shoulder 33 defining a second contact portion 34 configured to actively co-act with a first contact portion 26 of another panel, in coupled condition of such panels as will be discussed with reference to fig. 4. A top surface 35 of the lower lip 32 is smoothly curved at least partially and is configured as sliding surface for the at least partially rounded bottom surface 23 and/or side surface 23 of the front region 21 of the sideward tongue 20 of another panel during coupling of a first and second coupling part.

The upper surface 35 of the lower lip is provided with a staggered cut-out portion 35s, which is at least partially located underneath the upper lip 31, and which is configured to accommodate a terminal portion of the sideward tongue 20 of another panel.

The panel 1 comprises a core 1a, and a decorative top structure 12 affixed, either directly or indirectly, on top of said core.

An optional backing layer 105 is attached to a lower side of the core 1a.

The core 1a comprises at least one (mineral) wool layer at least partially, and optionally entirely, formed by man-made vitreous fibres bonded together by at least one cured thermoset polymeric binder material, typically a resin.

Preferably, at least a fraction of the man-made vitreous fibres are made of at least one material selected from the group consisting of: stone wool, mineral wool, slag wool, basalt wool, and glass fibres.

It is imaginable that the core 1a comprises a plurality of different wool layers and/or at least one non-wool layer, such as for example a glass fibre layer, a thermoplastic layer, and/or a cementitious layer.

The top structure 12 can be of various nature, wherein two embodiments 12a, 12b are shown in figure 2. In a first embodiment 12a, the top structure has a laminated structure, and comprises a decorative layer, in particular a thermoplastic or paper film carrying a, preferably digitally printed, decorative image, and at least one protective layer, such as a finishing layer, and/or a wear layer, and/or a lacquer, positioned on top of said decorative layer. Further embodiments have been described in the above description. Alternatively, or additionally, the top structure 12b may comprises a tile, in particular a mineral tile, preferably at least partially made of ceramic and/or stone, and/or any material chosen from the group consisting of: ceramic, stone, concrete, mineral porcelain, glass, quartz, soapstone, mosaic, granite, limestone and marble. Typically, these tiles are hard — even impossible — to profile, as a result of which the profile core offers a solution to manufacture interlockable mineral tiles. The top structure 12 may be glued, by means of an adhesive, and/or fused onto the core 1a.

The backing layer 105 is attached, directly or indirectly, to a rear side of the core 1a. The at least one backing layer is preferably at least partially made of a flexible material, preferably an elastomer. The thickness of the backing layer typically varies from about 0.1 to 2.5 mm. Non-limiting examples of materials whereof the backing layer can be made of are polyethylene, cork, polyurethane and ethylene- vinyl acetate. The thickness of a polyethylene backing layer 105 is for example typically 2 mm or smaller. The backing layer 105 commonly provides additional robustness, dimensional stability, and/or impact resistances to the panel as such, which increases the durability of the panel. Moreover, the (flexible) backing layer 105 may increase the acoustic (sound-dampening) properties of the panel 1.

In the following figures, the backing layer 105 and the top structure 12 have not been shown separately for clarity reasons, but may be incorporated in each of the figures shown.

Fig. 3 shows a method of coupling of two panels 1 and 1’, each being provided with first and second coupling parts 5 and 6 as shown in fig. 2. The two panels are coupled to each other by an angling movement over arrow MA. As evident from fig. 3, the curvature of top surface 35 of the lower lip 32 functions as sliding surface for the at least partially rounded bottom surface 23 and/or side surface 23 of the tongue 20.

Fig. 4 shows the coupling parts 5 and 6 of the two panels 1 and 1’ once the coupling shown in fig. 3 has been completed by the angling movement. The respective contact portions 26 and 34 in the shown coupled status, together create a tension force (T1) which forces the side edges 3 and 4 towards each other.

Further in the shown coupled status, the at least partially curved top surface 35 of the lower lip 32 and the passive bottom surface 27 of the sideward tongue 20 are mutually situated such that an intermediate space S is present adjacent to actively co-acting first and second contact portions 26 and 34. The passive bottom surface 27 is depicted as a substantially flat surface, but may alternatively have a concave or convex surface, as long as an amount of intermediate space S is maintained between tongue and recess in coupled status. A lower surface 36 of the upper lip 31 is at least partially inclined and configured to abut at least a part of the top surface 24 of the front region of the sideward tongue 20. The top surface 35 of the lower lip defines a deepest point 38 of the recess, wherein the shoulder 33 of the lower lip defines a highest point 39 of the lower lip, wherein said deepest point and highest point define a lower lip depth (LLD). On the upper side of the panels 1 and 1" which are forced together by the tension force from contact portions 26 and 34, a seam 40 is present which defines a vertical plane VP which subdivides the lower lip 32 into an inner lower lip part 32i and an outer lower lip part 320. The top surface of the shoulder part 33 is herein located at a distance from first coupling part 5, so that an intermediate space is present at this part as well. Fig. 5 shows a longitudinal cross-section of a panel 1 shown in fig. 1, along line B- B. At side edges 9 resp. 10, a third coupling part in the form of profile 7 resp. a fourth coupling profile in the form of profile 8 is provided. The third coupling part 7 comprises an upward tongue 71, an upward flank 72 situated at a distance from the upward tongue and an upward groove 73 formed in between the upward tongue 71 and the upward flank 72, wherein the upward groove is adapted to receive at least a part of a downward tongue 81 of the fourth coupling part 8 of another panel. The side of the upward tongue 71 facing the upward flank 72 is the inside 77 of the upward tongue, and the side of the upward tongue 71 facing away from the upward flank 72 is the outside 76 of the upward tongue. A first locking element 75 is provided at an outside of the upward tongue 71 facing away from the upward flank

72. The fourth coupling part 8 comprises a downward tongue 81, a downward flank 82 situated at a distance from the downward tongue, and a downward groove 83 formed in between the downward tongue 81 and the downward flank 82, wherein the downward groove 83 is adapted to receive at least a part of the upward tongue 71 of the third coupling part 7 of another panel. The side of the downward tongue 81 facing the downward flank 82 is the inside 87 of the downward tongue and the side of the downward tongue 81 facing away from the downward flank 82 is the outside 86 of the downward tongue 81. A second locking element 85 adapted for co-action with a first locking element 75 of another panel, is provided at the downward flank 82.

Fig. 6 shows how the third and fourth coupling profiles 7 and 8 of fig. 5 can be coupled to each other when connecting a panel 1 and a panel 1’ to each other. The panel 1’ is hereby moved vertically downwards along the arrow, wherein the profiles 7 and 8 engage with each other by receiving upward tongue 71 in downward groove 83 and receiving downward tongue 81 in upward groove 73.

Fig. 7 shows in more detail the side edges 7 and 8 in coupled condition, after the coupling by vertical movement as shown in fig. 6 has been completed. It is noted that the side edges 7 and 8 of the embodiment of fig. 7 contain some slight adaptations over the embodiment shown in fig. 5 and 6, which are directly visible from the figures, and further explained below. As far as figs. 5-7 have the same features in common, these are indicated by the same reference numerals. The inside 77 of the upward tongue 71 is in contact with the inside 87 of the downward tongue 81 of another panel, such that the panels create a tension force (T2) which forces the side edges 7 and 8 towards each other. Part of the inside 77 of the upward tongue is inclined towards the upward flank 72, and part of the inside 87 of the downward tongue 81 is inclined towards the downward flank 82, such that the two coupled panels are interlocked in a direction perpendicular to the plane of the panels (i.e. in a vertical direction). Additionally, the first and second locking elements 75 and 85 interlock with each other, further contributing to the vertical interlocking of the coupled panels. The first locking element is a bulge 75, the second locking element is a recess 85. The bulge 75 has an upper portion 90 and an adjoining lower portion 88, wherein the lower portion 88 comprises an inclined locking surface and the upper portion 90 comprises a, preferably curved, guiding surface. The recess 85 comprises an upper portion 94 and an adjoining lower portion 92, wherein the lower portion 92 comprises an inclined locking surface.

The respective upper portions 90 and 94 are at a distance from each other, thus allowing for an intermediate space. At the upper side of the coupled side edges 7 and 8, the upper contact surfaces 95 and 96 are forced together due to the interaction of the insides 77 and 87. In addition, the respective upper contact surfaces 95 and 96 are provided with a bulge 98 and a recess 97, which interlock with each other in the coupled state. Above the bulge 98 and recess 97 respective inclined contact surfaces 99a and 99b are provided which engage with each other. Figure 8 shows an alternative embodiment of the side edges 3 and 4 according to fig. 2, wherein the upper surface 24 of the front region 21 of the sideward tongue and a side surface 23 of the front region 21 of the sideward tongue are connected by means of a transitional convex surface 100, and the lower surface 36 of the upper lip 31 and a side surface 102 of the upper lip 31 are connected by means of a transitional convex surface 104. All other features of the side edges 3 and 4 are similar to fig. 2. The shown embodiment allows for a coupling movement by shifting the panels towards each other in a planar direction as indicated by the arrow ‘Snap’.

Figure 9 shows an alternative embodiment of the side edges 3 and 4 according to fig. 2, wherein the upper surface 35 of the lower lip 32 has a staggered cut-out portion 35s which is complementary in size to the terminal portion 23 of the tongue 20, so that it encloses the portion 23 in a clamping way. All other features of the side edges 3 and 4 are similar to fig. 2.

The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts may be applied without, in so doing, also applying other details of the described example. It is not necessary to elaborate on examples of all conceivable combinations of the above- described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application.

It will be apparent that the invention is not limited to the working examples shown and described herein, but that numerous variants are possible within the scope of the attached claims that will be obvious to a person skilled in the art.

The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof.

Claims (33)

Conclusions A decorative panel, in particular a floor, ceiling or wall panel, comprising: - a core provided with a top and a bottom, - a decorative top structure that is bonded directly or indirectly to the top of the core, - a first panel edge comprising a first coupling profile, and a second profile edge comprising a second coupling profile which is designed to interlockingly engage the first coupling profile of an adjacent panel, both in horizontal and vertical direction, - wherein the core comprises at least one wool layer comprising at least formed in part from man-made vitreous fibers bonded together by at least one cured thermoset polymeric bonding material. The decorative panel of claim 1, wherein at least a fraction of the man-made vitreous fibers are made of at least one material selected from the group consisting of: rock wool, mineral wool, slag wool, basalt wool and glass fibers. The decorative panel according to claim 1 or 2, wherein at least one binding material is a material selected from the group consisting of: urea-modified phenol-formaldehyde resin, and a reaction product of alkanolamine and carboxylic acid anhydride. A decorative panel according to any one of the preceding claims, wherein at least one bonding material is a material selected from the group consisting of: acrylic resin and an epoxy resin. A decorative panel according to any one of the preceding claims, wherein at least one binding material is formed by a sugar component, preferably selected from the group consisting of: sucrose, reducing sugars, in particular dextrose, polycarbohydrates, and mixtures thereof. A decorative panel according to any one of the preceding claims, wherein the core comprises at least one binding material selected from the group consisting of: urea-modified phenol formaldehyde resin, and a reaction product of alkanolamine and carboxylic anhydride, and wherein the core comprises at least one co binder material selected from the group consisting of: acrylic resin and an epoxy resin. A decorative panel according to claim 6, wherein the amount of solid based co-binder is 1 to 50% by weight of the total binder, preferably 5 to 35% by weight of the total binder. A decorative panel according to any one of the preceding claims, wherein the core comprises a mixture of binding materials, wherein a first binding material has a higher curing temperature and/or faster curing speed than at least one second binding material. A decorative panel according to any one of the preceding claims, wherein the core comprises at least one fluorescent compound, preferably selected from the group consisting of: xanthene, acridine, quinine, quinine derivatives, coumarin, aryisulphonate. A decorative panel according to any preceding claim, wherein the core comprises airgel particles. The decorative panel of claim 10, wherein the weight of airgel particles in the core is greater than the weight of bonding material and/or the weight of the man-made vitreous fibers in the core. A decorative panel according to any one of the preceding claims, wherein the fiber orientation in at least one wool layer of the core is substantially vertical. A decorative panel according to any one of the preceding claims, wherein the core comprises at least one base wool layer comprising a first mineral wool, and at least one upper wool layer placed on top of the base wool layer and comprising a second mineral wool, wherein the first wool and second wool have different material compositions and/or different structural properties. A decorative panel according to any one of the preceding claims, wherein the panel, in particular the core, comprises at least one reinforcing layer, preferably a non-woven layer or a woven layer, in particular a cloth. The decorative panel of claim 14, wherein the reinforcing layer comprises glass fiber. A decorative panel according to any one of the preceding claims 14-15, wherein the reinforcing fiber comprises natural fibers such as jute, and/or synthetic fibres, in particular polymer fibres. A decorative panel according to any one of the preceding claims 14-16, wherein the at least one reinforcement layer is included in the core and is preferably enclosed by two layers of wool. A decorative panel according to any one of the preceding claims, wherein the panel comprises a plurality of reinforcement layers, preferably at least one first reinforcement layer is present in an upper part of the core, and wherein at least one second reinforcement layer is present in a lower part of the core. core. A decorative panel according to any one of the preceding claims, wherein at least one core has a density lower than 1 kg/m 3 . A decorative panel according to any one of the preceding claims, wherein the decorative top structure is bonded to the core by means of a water resistant adhesive. A decorative panel according to any one of the preceding claims, wherein the decorative top structure is fused to the core, preferably without using a separate adhesive. A decorative panel according to any one of the preceding claims, wherein a bottom side of the decorative top structure is forced into a top side of the core, preferably to a depth greater than 0.1 mm. A decorative panel according to any preceding claim, wherein the decorative top structure comprises at least one decorative bearing, and at least one transparent wear layer covering the decorative layer. A decorative panel according to any one of the preceding claims, wherein the top decorative structure comprises from bottom to top: i. optionally, at least one base coat, in particular a base coat, il. at least one decorative layer, in particular a thermoplastic or paper film provided with a decorative print, ii. at least one transparent wear layer covering the decorative layer, and iv. optionally, at least one lacquer layer, preferably a lacquer layer cured under UV light, covering the wear layer. A decorative panel according to any one of the preceding claims, wherein the first coupling profile comprises: - an upward tongue, - at least one upward flank present at a distance from the upward tongue, - an upward groove formed between the upward tongue and the upward tongue flank wherein the upward groove is adapted to receive at least part of a downward tongue of a second coupling profile of an adjacent panel, and - at least a first locking element, preferably provided on a distal side of the upward tongue that of the upward flank is turned away, and wherein the second coupling profile comprises: - a first downward tongue, - at least one first downward flank present at a distance from the downward tongue, - a first downward groove formed between the downward tongue and the downward flank, wherein the downward groove is adapted to receive at least a part of an upward tongue of a first coupling profile of an adjacent panel lugs, and - at least a second locking element adapted to cooperate with a first locking element of an adjacent panel, and preferably provided on the downward flank. A decorative panel according to any one of the preceding claims, wherein the panel comprises at least a third coupling profile and at least a fourth coupling profile, which are respectively present on a third and a fourth panel edge, the third coupling profile comprising: - a lateral tongue which extending in a direction substantially parallel to the top of the core, - at least one second downward flank present at a distance from the lateral tongue, and - a second downward groove formed between the lateral tongue and the second downward flank, and wherein the fourth coupling profile comprises: - a third groove adapted to receive at least a part of the lateral tongue of the third coupling profile of an adjacent panel, said third groove being defined by an upper lip and lower lip, the lower lip being provided with a upward locking element, wherein the third and fourth coupling profile are designed such that two such panels coupled together by means of a twisting movement, wherein in engaged condition at least a portion of the lateral tongue of a first panel is inserted into the third groove of an adjacent second panel, and wherein at least a portion of the upward locking element of the second panel is inserted into the second downward groove of the first panel. A decorative panel according to any one of the preceding claims, wherein at least a part of at least one coupling profile, preferably of each coupling profile, is integrally made of material of the core. A decorative panel according to any one of the preceding claims, wherein at least one wool layer has a varying density in the thickness direction of the wool layer. A decorative panel according to any one of the preceding claims, wherein at least one wool layer has a varying density in a width direction and/or length direction of the wool layer. A decorative panel according to any one of the preceding claims, wherein at least one wool layer is at least partially filled with an inert filler. A decorative panel according to any one of the preceding claims, wherein the panel thickness is between 2 and 10 mm, preferably between 3 and 10 mm. A core suitable for use in a decorative panel according to any one of the preceding claims, wherein a first core edge comprises at least a part of the first coupling profile, and a second core edge comprises at least a part of the second coupling profile, which second coupling profile is designed to Lockingly engaged in horizontal and vertical direction on the first coupling profile of an adjacent panel or of an adjacent core, the core comprising at least one wool layer formed at least in part from man-made vitreous fibers joined together joined by at least one cured thermosetting polymeric bonding material. A decorative covering, in particular a decorative floor, ceiling or wall covering, comprising a plurality of mutually coupled decorative panels according to any one of claims 1-30.