Decorative surface covering comprising carbon-based porous filler dispersed in polymer matrix

Abstract

A carbon-based porous filler (CPF) for incorporation into a thermoplastic material, such as a decorative surface covering, is presented. It has been recognized that a CPF having a carbon content of at least 70% of the dry weight of the CPF and a specific surface area of from 5 m2 / g to 500 m2 / g measured according to Standard ISO 9277: 2010 (Bluerr-Hermite-Teller (BET) method) can impart advantageous mechanical properties to thermoplastic materials, in particular a reduced density (compared to conventional fillers) and a specific stiffness above expectation.

Description

Background of the Invention

[0002] The present invention generally relates to decorative surface coverings, such as, for example, floor coverings (flooring materials), wall coverings or ceiling coverings. The present invention more particularly relates to a core layer of a decorative surface covering, the core layer comprising a carbon-based porous filler (CPF) dispersed in a thermoplastic polymer matrix and optionally additives such as, for example, processing aids, lubricants, compatibilizers, etc.

[0003] Synthetic decorative surface coverings are largely based on petroleum, that is, the polymers they contain are obtained from hydrocarbons derived from fossil fuels. Efforts have been made to reduce the environmental footprint of surface coverings by increasing the ratio of renewable materials to non-renewable materials. For example, natural fiber plastic composites (NFPC) are composite materials consisting of a polymer matrix embedded with natural fibers, such as, for example, biomass fibers, such as bamboo fibers, hemp fibers, flax fibers, wood fibers, etc. A subgroup of NFPC is wood-plastic composite (WPC), which contains wood fibers and plastics. NFPC is considered to have a problem of low stress transfer efficiency between the polymer matrix and the natural fibers.

[0004] US 10,920,370 proposes a floor covering comprising an upper wear layer and a backing layer, wherein the backing layer comprises concentrated carbon as a filler. When subjected to a Life Cycle Assessment, the floor covering is praised as having a negative carbon footprint.

[0005] US10,414,880 discloses carbonized biomass as a substitute for carbon black in the production of synthetic plastics. Carbon black is obtained from non-renewable resources such as natural gas or petroleum-derived heavy oil by chemical-thermal conversion. The document is more specifically related to a masterbatch for producing a composite, the masterbatch comprising a blend of carbonized biomass and a carrier resin. The carbonized biomass has a particle size of less than about 100 microns, the concentration of the carbonized biomass in the masterbatch is from about 25% wt. to about 75% wt., and the concentration of the carrier resin in the masterbatch is from about 25% wt. to about 75% wt. SUMMARY OF THE INVENTION

[0007] According to a general aspect of the present invention, a carbon-based porous filler (CPF) is provided for incorporation into a thermoplastic material, such as a decorative surface covering. It has been recognized that a CPF having a carbon content of at least 70% of the dry weight of the CPF and a 5 m / s strength measured according to standard ISO 9277:2010 (Bruer-Emmett-Teller (BET) method) can impart advantageous mechanical properties to the thermoplastic material, in particular a reduced density (compared to conventional fillers) and a higher than expected specific stiffness and stress at rupture. 2 / g to 500m 2 / g, preferably 40m 2 / g to 500m 2 / g specific surface area (SSA).

[0008] The benefits of CPF, specifically in rigid Luxury Vinyl Tile (LVT) flooring, were demonstrated at a pilot scale by testing thermoplastics with varying volume fractions of CPF. Testing of the thermoplastics included 3-point bend testing, dynamic mechanical analysis (DMA), and thermal expansion testing. Results showed that increasing the volume fraction of CPF increased the fracture stress while reducing the stress of the thermoplastic (compared to CaCO-filled) 3 The DMA results show that the presence of CPF reduces polymer chain mobility, indicating better polymer-filler interaction. Perhaps notably, the benefits from CPF can be obtained when using CPF as the sole filler or in combination with other fillers, such as mineral fillers, such as calcium carbonate, talc, chalk, etc.

[0009] According to an aspect of the invention, a decorative surface covering, such as a floor covering, a wall covering or a ceiling covering, comprises a structural core layer comprising as a matrix a thermoplastic material comprising one or more thermoplastic polymers and a CPF dispersed in the matrix. The CPF has a carbon content of at least 70%, preferably at least 75%, more preferably at least 80% of the dry weight of the CPF and a 5 m³ carbon content measured according to standard ISO 9277:2010 (Bruer-Emmett-Teller (BET) method). 2 / g to 500m 2 / g, preferably 20m 2 / g to 450m 2 / g, and more preferably 40m 2 / g to 400m 2 / g specific surface area.

[0010] CPF can have at least 10 -12 The isotope ratio 14 C / 12 C, preferably at least 1.2·10 -12 The isotope ratio 14 C / 12 C. Understandably, in fossil fuels 14 C is (essentially) absent, the fossil fuels have been stored in geological reservoirs for millions of years, i.e. 14 The radioactive decay time of C is several orders of magnitude longer (half-life of 5730 ± 40 years). Therefore, the isotope ratio is converted into the ratio of carbon derived from renewable resources (hereinafter: biochar) to total carbon (including carbon derived from petroleum ("petroleum carbon") and biochar). At least 10 -12 The isotope ratio 14 C / 12 C( 14 C / 12 C ratio) reflects the biomass carbon content from about 80% to 100% by weight of total carbon. 1.2·10 -12 or greater isotope ratio 14 C / 12 C indicates a biochar content close to 100% of the total carbon. Preferably, the thermoplastic material as a whole (i.e. taking into account the carbon content of the polymer resin, any other fillers and any additives) has a biochar / total carbon ratio of at least 25% by weight (corresponding to at least 2.5·10 -13 The isotope ratio 14 C / 12 C), more preferably a biochar / total carbon ratio of at least 40% by weight (corresponding to at least 4·10 -13 The isotope ratio 14 C / 12 C).

[0011] According to a preferred embodiment of the present invention, CPF comprises biochar or consists of biochar (provided that the biochar meets the above requirements for CPF). Biochar refers to a carbon-rich solid material obtained by pyrolysis of biomass (i.e., by thermal decomposition of biomass in an oxygen-poor or oxygen-free environment) or by thermocatalytic depolymerization of biomass.

[0012] The thermoplastic material may include one or more additional fillers dispersed therein. The additional filler may be selected, for example, from ground limestone, dolomite, (precipitated) calcium carbonate, zeolite, magnesium carbonate, chalk, phyllosilicate, glass particles (e.g. glass fibers or glass flakes) and aluminum trihydroxide. Flake fillers or fibrous fillers may be used to advantageously change the mechanical properties of the thermoplastic material, such as the coefficient of thermal expansion. Fibrous fillers that can be used in the context of embodiments of the present invention may include glass fibers or biomass fibers, such as bamboo fibers, hemp fibers, flax fibers, wood fibers, etc., preferably delignified cellulosic fibers. Particularly preferred fillers may include inorganic flaky fillers, such as, for example, sheet silicates (particularly talc or mica), clays, montmorillonites, glass flakes and lamellar double hydroxides. The term "phyllosilicate" refers to a mineral from the silicate group, in which the silicate anions are usually arranged in layers, such as phyllosilicates. For example, layered silicates may include minerals from the mica group, the chlorite group, the kaolinite group, and the serpentine group.

[0013] Preferably, the thermoplastic material may comprise from 2 to 70% by weight, more preferably from 3 to 60% by weight and still more preferably from 5 to 40% by weight of CPF.

[0014] The thermoplastic material may have a total filler content of from 5% to 70% by weight, preferably from 10% to 60% by weight. Preferably, CPF represents at least 30% by weight of the total filler content, more preferably at least 40% by weight, still more preferably at least 50% by weight, even more preferably at least 60% by weight, even more preferably at least 70% by weight, most preferably at least 80% by weight, and extremely preferably at least 90% by weight.

[0015] Preferably, the CPF has a D50 (median) diameter in the range of from 1 μm to 50000 μm, more preferably in the range of from 2 μm to 5000 μm, even more preferably in the range of from 5 μm to 1000 μm, still more preferably in the range of from 15 μm to 500 μm, and most preferably from 30 μm to 100 μm. In the context of the present document, the D50 value means the D50 value obtained from the largest Feret diameter, the largest Feret diameter being measured from an image analyzed (using dynamic image analysis) according to standard ISO 13322-2:2021. According to other embodiments, preferably, the CPF has a D50 (median) diameter in the range of from 1 μm to 1000 μm, more preferably from 10 μm to 200 μm, even more preferably in the range of from 15 μm to 150 μm, and still more preferably in the range of from 20 μm to 100 μm. In addition, the D10 diameter of the CPF may be in the range of 1 μm to 1000 μm, preferably in the range of 4 μm to 100 μm, more preferably in the range of 10 μm to 50 μm, and still more preferably in the range of 20 μm to 40 μm. Alternatively, the D10 diameter may be in the range of 5 μm to 100 μm, more preferably in the range of 10 μm to 50 μm, and still more preferably in the range of 10 μm to 40 μm. The D90 diameter of the CPF may be in the range of 100 μm to 80000 μm, preferably in the range of 150 μm to 50000 μm, more preferably in the range of 200 μm to 2000 μm, and still more preferably in the range of 300 μm to 1000 μm. Alternatively, the CPF may have a D90 diameter in the range from 100 μm to 3000 μm, more preferably in the range from 120 μm to 2000 μm, still more preferably in the range from 120 μm to 1000 μm, even more preferably in the range from 200 μm to 1000 μm.

[0016] Preferably, the CPF may comprise particles anchored in a thermoplastic polymer matrix by mechanical and / or chemical interlocking caused by the thermoplastic polymer having infiltrated the pores of the particles. The polymer infiltrating into the pores of the CPF, at least partially filling the pores of the CPF, results in a strong attachment between the filler and the polymer matrix by mechanical interlocking. The pores also provide an increased surface area on which adsorption and / or chemical bonding between the polymer and the CPF can occur. This contributes to good stress transfer between the components of the thermoplastic material and ultimately results in a higher specific stiffness.

[0017] Advantageously, the CPF may comprise particles having multidirectional porosity, ie particles having first pores extending in a first direction and second pores extending in a second transverse direction. Thus, the effect of mechanical interlocking may be enhanced.

[0018] According to an embodiment, the CPF may have pores with diameters ranging from 0.5 μm to 30 μm, preferably ranging from 1 μm to 20 μm, more preferably ranging from 1 μm to 10 μm.

[0019] The decorative surface covering may comprise or may be a surface covering tile, such as a flooring tile, a wallcovering tile or a ceiling covering tile, comprising a decorative layer, a wear layer and optionally a backing layer.

[0020] The decorative layer may comprise a printing substrate carrying a print, the printing substrate having a hiding power H10 (opacity) of at least 80%, preferably at least 90%, measured according to standard ISO 6504-3:2019 (method A). The hiding power of the printed substrate may be obtained by a Spectro-guide 45 / 0 gloss device according to standard ISO 6504-3:2019. The decorative print itself may comprise a digital print or a print produced by a similar printing technique, such as rotogravure, photogravure, offset printing, or the like.

[0021] The wear layer can be transparent or translucent. Optionally, the wear layer can include a crosslinked topcoat (e.g., a crosslinked topcoat comprising epoxy resin, polyurethane, polyurethane acrylate, polyester polyurethane acrylate, polyurethane methacrylate and / or polyester polyurethane methacrylate), or consist of the crosslinked topcoat. Optionally, the decorative layer and / or the wear layer can include an embossed pattern aligned with the decorative print of the decorative layer. The wear layer and / or the topcoat can each include one or more layers or be constructed of one or more layers. These can be distinguishable from each other in the final product, or not. The embossed pattern can be the result of mechanical embossing (using an embossed roller or plate) or three-dimensional digital printing.

[0022] The core layer may comprise or consist of a rigid core layer having a deformation angle of less than 7 degrees, more preferably less than 5 degrees, most preferably less than 3 degrees, the deformation angle being measured by the following deformation test (cantilever test) carried out under ambient temperature and pressure conditions (at 23° C. and at atmospheric pressure, i.e. about 1000 hPa). According to the deformation test, a rectangular sample (in this case the core layer) of dimensions 160 mm×450 mm is clamped in a horizontal cantilever state to obtain a 160 mm×300 mm protrusion of the sample. The protrusion is initially supported over its entire length and width by removable horizontal supports. The deformation angle is measured 30 seconds after the removal of the supports, which prevent the protrusion from deforming under the influence of its own weight. The deformation angle is a measure of the flexural strength of the structure being tested.

[0023] According to a preferred embodiment, the decorative surface covering may comprise or consist of a floor tile, the floor tile comprising a first locking connection along a first edge, a second locking connection along a second edge (opposite to the first edge), the first locking connection and the second locking connection having complementarily profiled, such that the floor tile can be interlocked with another floor tile by engaging the first locking connection or the second locking connection of the floor tile with the second locking connection or the first locking connection of another floor tile, respectively. Optionally, the floor tile may also comprise a third locking connection along a third edge, a fourth locking connection along a fourth edge (opposite to the third edge), the third locking connection and the fourth locking connection having complementarily profiled, such that the floor tile can be interlocked with another floor tile by engaging the third locking connection or the fourth locking connection of the floor tile with the fourth locking connection or the third locking connection of another floor tile, respectively. The first locking connection and the third locking connection may have the same shape, in which case, advantageously, the second locking connection and the fourth locking connection may also have the same shape, complementary to the first locking connection and the third locking connection. Alternatively, the first locking connection portion and the third locking connection portion may have different shapes, and therefore, the second locking connection portion and the fourth locking connection portion may also have different shapes.

[0024] The thermoplastic material comprises one or more thermoplastic polymers as a matrix, wherein the matrix is ​​embedded with CPF and any other additional fillers. The thermoplastic polymer may include, for example: polyacrylic acid, polyacrylate, polyamide (PA), polyester, polylactic acid (PLA), polycarbonate (PC), polyethersulfone (PES), polyetheretherketone (PEEK), polyvinyl butyral (PVB), polyetherimide (PEI), polyethylene, polypropylene (PP), polystyrene, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), acrylonitrile butadiene styrene (ABS), thermoplastic cellulose esters, etc. According to a particularly preferred embodiment, the one or more thermoplastic polymers of the thermoplastic material may include polyvinyl chloride or polyvinyl butyral, preferably, recycled polyvinyl chloride and / or recycled polyvinyl butyral.

[0025] According to a particularly preferred embodiment of the invention, the decorative surface covering is (essentially) free of PVC.

[0026] The thermoplastic material may comprise a plurality of thermoplastic polymer species. In this case, it may be preferred that one or at most two polymer species predominate, i.e., it or they represent at least 85% by weight (85 phr) of the total thermoplastic polymer content of the thermoplastic material. Preferably, the additional thermoplastic polymer species may represent at most 15% by weight of the thermoplastic polymer content of the thermoplastic material.

[0027] According to a particular embodiment, the decorative surface covering comprises a core layer comprising as matrix a thermoplastic material comprising one or more thermoplastic polymers comprising polyvinyl chloride, polypropylene or polyvinyl butyral, preferably recycled polyvinyl chloride, polypropylene or polyvinyl butyral, and further fillers selected from: calcium carbonate and / or layered silicates, such as talc or clay.

[0028] According to a particularly preferred embodiment of the invention, the decorative surface covering comprises a core layer comprising as matrix a thermoplastic material comprising one or more thermoplastic polymers comprising polypropylene and an additional filler being: calcium carbonate and / or talc.

[0029] In one aspect, the present invention also relates to a process for producing a core layer of a decorative surface covering, the process comprising the steps of:

[0030] 1) 5m.s -1 Up to 85m.s -1mixing a thermoplastic material comprising one or more thermoplastic polymers and a carbon-based porous filler (CPF) at a peripheral speed of 1000 rpm until the mixture of the thermoplastic material and the CPF reaches a temperature of 95° C. to 125° C., and

[0031] 2) extruding a mixture of thermoplastic material and CPF at a temperature of at least 100° C. by using at least one screw with a speed of from 50 s -1 Up to 400s -1 The local maximum shear rate rotates.

[0032] This process allows to reduce the size of CPF particles and / or reduce the intrinsic moisture of CPF. The reduction of CPF particle size leads to improved dispersibility of CPF in thermoplastic materials and increased mechanical effect of CPF.

[0033] Thus, CPF particles having a D50 diameter greater than 50000 μm can be used to manufacture a core layer for a decorative surface covering according to the present invention. Implementation of the process allows the use of a wider range of CPF particle sizes. Both steps 1 and 2 can be combined in order to optimize the properties of the CPF with respect to particle size and moisture content. Steps 1 and 2 can be performed once or several times. Step 1 of the process results in obtaining CPF particles having a D50 diameter of less than 50000 μm. Step 1 of the process can be performed in a high-speed mixer. Preferably, step 1 of the process can be performed at a temperature from 100°C to 120°C, and more preferably at a temperature from 105°C to 115°C. Step 2 of the process allows the moisture content of the core layer to be reduced from 2 to 5 times. Step 2 of the process can be performed using a single screw extruder or a twin screw extruder and / or using continuous kneading machine technology. At the end of step 2, the moisture content of the resulting core layer can be reduced by 90%wt of the initial moisture content of the mixture of thermoplastic material and CPF filler.

[0034] According to an embodiment of the present invention, the core layer may include a core layer assembly comprising at least two layers of different construction, for example, comprising different thermoplastic materials or consisting of different thermoplastic materials. The core layer assembly may, for example, include three or more layers, the three or more layers including two outer layers sandwiching one or more inner layers. The two outer layers may be unfoamed layers consisting of thermoplastic materials. The one or more inner layers may include at least one foamed layer, the foamed layer optionally comprising a thermoplastic material or another thermoplastic material containing one or more thermoplastic polymers as a matrix and CPF dispersed in the matrix, preferably, the CPF having a carbon content of at least 70% by dry weight and a 5m 2 / g to 500m 2 / g, preferably 40m 2 / g to 500m 2 / g specific surface area.

[0035] According to an embodiment, the core layer can be prepared by a calendering process when it includes a core layer component. More specifically, at least two separate layers having a thickness included in the range from 0.05 mm to 2.5 mm can be calendered at a roller temperature from 120° C. to 220° C. at a speed of 1 m / min to 100 m / min. The at least two separate layers can also be calendered together with at least one reinforcing layer (such as, for example, glass veil or glass grid), at least one decorative layer and at least one wear-resistant layer to obtain a decorative surface covering having a thickness included in the range from 1 mm to 5 mm.

[0036] According to another embodiment, the core layer can be obtained by agglomeration of pellets. In the context of the present invention, the pellets comprise a thermoplastic material comprising one or more thermoplastic polymers as a matrix and CPF dispersed in the matrix and at least one filler. In this case, the core layer can be obtained by compacting the pellets at a temperature of from 160° C. to 220° C. and preferably at a pressure of from 1 bar to 20 bar.

[0037] According to a particularly preferred embodiment, the decorative surface covering is or comprises a surface covering tile, such as a floor covering, a wall covering or a ceiling covering, the decorative surface covering comprising a decorative layer, a wear layer and a rigid core layer (serving as a structural support for the decorative layer and the wear layer), the rigid core layer comprising as a matrix a thermoplastic material comprising one or more thermoplastic polymers and a CPF dispersed in the matrix, the CPF having a carbon content of at least 70%, preferably at least 75%, more preferably at least 80% by dry weight and a 5 m³ carbon content measured according to standard ISO 9277:2010. 2 / g to 500m 2 / g, preferably 40m 2 / g to 500m 2 / g specific surface area, CPF has at least 10 -12 The isotope ratio 14 C / 12 C, preferably at least 1.2·10 -12 The isotope ratio 14 C / 12C, the thermoplastic material comprises from 2% to 70% by weight, preferably from 3% to 60% by weight, more preferably from 5% to 40% by weight of CPF, the thermoplastic material has a total filler content of from 5%-70% by weight, preferably from 10% to 65% by weight, and more preferably from 10% to 60% by weight, the CPF particles have a D50 diameter in the range of from 15 μm to 100 μm, preferably in the range of from 20 μm to 80 μm, the CPF comprises particles anchored in a thermoplastic polymer matrix by interlocking caused by thermoplastic polymer infiltrating the pores of the particles, the CPF comprises particles with multi-directional porosity, i.e. particles with first pores extending in a first direction and second pores extending in a second transverse direction. The core layer is rigid, i.e. the core layer has a deformation angle of less than 7 degrees, more preferably less than 5 degrees, most preferably less than 3 degrees, the deformation angle being measured by a deformation test. According to a particularly preferred variant of this embodiment, the thermoplastic material comprises an additional filler dispersed therein, the additional filler being selected from ground limestone, dolomite, calcium carbonate (e.g. precipitated calcium carbonate), zeolite, magnesium carbonate, chalk, layered silicates (e.g. talc or clay), glass particles and aluminum trihydroxide. Preferably, the core layer is a core layer assembly comprising at least two layers of different construction. Preferably, the core layer assembly may comprise three or more layers, the three or more layers comprising two outer layers sandwiching one or more inner layers. Preferably, the two outer layers are unfoamed layers consisting of a thermoplastic material, while the one or more inner layers may comprise at least one foamed layer, the foamed layer optionally comprising as a matrix a thermoplastic material comprising one or more thermoplastic polymers or another thermoplastic material and a CPF dispersed in the matrix, the CPF having a carbon content of at least 70% by dry weight and a carbon content of at least 50% by weight measured according to standard ISO 9277. 2 / g to 500m 2 / g, preferably 20m 2 / g to 450m 2 / g, and most preferably 40m 2 / g to 400m 2 / g specific surface area.

[0038] As used herein, "isotope ratio" refers to the ratio of the amount (moles) of a first isotope of a chemical species to the amount (moles) of a second isotope of the chemical species.

[0039] Unless contradicted by the context, when referring to the "diameter" of a particle herein, it means the maximum distance between two parallel planes tangent to the particle that can be measured for the particle. In other words, the diameter of a particle corresponds to the maximum value of all Feret's diameters that can be measured for the particle. The Feret's diameter along a specified direction is defined as the distance between two parallel planes tangent to the particle and orthogonal to the specified direction. As used herein, the expression "aspect ratio" refers to the ratio between the shortest Feret's diameter and the longest Feret's diameter of a particle. When the expression "aspect ratio" is used to define a group of particles (such as, for example, fillers), it refers to the ratio between the average shortest Feret's diameter and the average longest Feret's diameter. The D50 diameter refers to the median diameter of the particles in a given group, i.e., the value at which 50% of the particles in a given group have a diameter equal to or lower than it. The expressions "D10 diameter" and "D90 diameter" refer to the values ​​at which 10% and 90% of the particles in a given group have a diameter equal to or lower than it, respectively.

[0040] Terms such as "upper", "lower", "lower", "upper", "horizontal", "vertical", "above", "below", "top" and "bottom" and their derivatives (e.g., "horizontally", "upward", etc.) refer to the orientation of a surface covering when it is laid with its decorative surface oriented upward. For a floor tile or flooring, this orientation corresponds to the state of the floor tile or flooring when in use as intended by the designer, i.e., laid on the ground. Terms relating to the orientation of surface coverings are adopted herein for ease of description and as a naming convention. They should be interpreted as referring to the relative orientation of different parts and are not intended to imply a particular absolute orientation of a tile or flooring component in space. For example, arranging a tile in such a way that its decorative surface is inverted does not prevent the decorative surface from being considered as a top surface.

[0041] As used herein, the qualifier "decorative" is intended to imply that the article thus defined, such as a surface covering, remains visible in normal use (an article working as a finish). However, the use of this term should not be considered to imply any particular aesthetic appearance or any particular aesthetic design. The expression "decorative layer" refers to a layer having a decorative pattern. Examples of decorative layers include printed layers, in particular rotogravure printed layers and digitally printed layers.

[0042] The expression "surface normal" refers to the direction perpendicular to the surface of the decorative side (top side) of the surface covering.

[0043] As used herein, the expression "thermoplastic material" encompasses a blend of plastic polymer materials that becomes flexible or moldable at a certain high temperature and solidifies upon cooling, the solidification being reversible by heating the material again to the high temperature. Thermoplastic (polymer) materials may comprise thermoplastic polymers and optionally one or more plasticizers, (mineral or organic) fillers and further additives (e.g., impact modifiers, compatibilizers, processing aids). In the context of this document, two or more initially separate thermoplastic materials that have been intimately blended together must be considered as one thermoplastic material in their blended state. Therefore, when referring to a surface covering or any part thereof comprising two or more thermoplastic materials herein, it is understood that the two or more thermoplastic materials exist as physically separate volumes, for example, as different layers, as different distinguishable particles, or the like.

[0044] In contrast to "thermoplastic", the expression "cross-linked" defines a polymer material (such as, for example, a top coat) that has been irreversibly hardened by cross-linking between polymer chains so as to produce a difficult-to-melt and insoluble network of polymers. Cross-linked (polymer) materials may include, for example, one or more thermosetting polymers or radiation-cured polymers. Radiation-cured polymers include in particular UV-cured polymers and / or electron beam-cured polymers. Cross-linked (polymer) materials may include thermosetting polymers and / or radiation-cured polymers (e.g., polyurethanes, polyimides, epoxy resins, etc.) and optionally one or more plasticizers, (mineral or organic) fillers and further additives (e.g., impact modifiers, photoinitiators, antioxidants, etc.) or processing aids.

[0045] As used herein, in the context of a composition, the expression "part(s)" means parts by weight.

[0046] In this document, the verb "to comprise" and the expression "to be comprised of" are used as open transition phrases, meaning "to include" or "to consist of at least". Unless the context implies otherwise, the use of the singular form is intended to cover the plural, except when the cardinal number "one" is used: "one" in this document means "exactly one". Ordinal numbers ("first", "second", etc.) are used in this document to distinguish different instances of a common object; the use of these expressions is not intended to imply a particular order (in space or time), importance, rank, or quantitative limitation. In addition, when multiple instances of an object refer to an ordinal number, this does not necessarily mean that there are no other instances of the object (unless this is clearly inferred from the context). When this specification refers to "an embodiment", "an embodiment", "embodiments", etc., this means that the features of these embodiments can be used in the combinations explicitly presented, but also means that these features can be combined across embodiments without departing from the present invention, unless it is inferred from the context that these features cannot be combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] As an example, preferred non-limiting embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0049] Figure 1 : is a schematic cross-sectional view of a surface covering brick according to an embodiment of the present invention;

[0050] Figure 2 : is a diagram of a deformation test showing a cantilever sample in an initial support state; and

[0051] Figure 3 : is an illustration of a deformation test, which shows the cantilever sample after the support of the protruding part is removed;

[0052] Figure 4 : are FT-IR spectra of three different CPFs used in the examples discussed below;

[0053] Figure 5 : Graph showing specific stiffness as a function of filler content measured (a) on samples with CPF and (b) on comparative samples with calcium carbonate filler;

[0054] Figure 6 : The fracture strain of samples containing different volume fractions of carbon-based porous fillers and calcium carbonate is depicted;

[0055] Figure 7: shows the ultimate stress values ​​determined in a 3-point bending test on samples with CPF and comparative samples;

[0056] Figure 8 : shows the evolution of the loss factor, i.e. the ratio between the loss modulus E" and the storage modulus E', as a function of temperature for thermoplastic materials with different CFP contents;

[0057] Fig. 9 : shows the loss factor as a function of temperature in thermoplastic materials containing calcium carbonate or CPF, respectively;

[0058] Fig.10 : shows the Cole-Cole plot of samples with different CFP contents;

[0059] Fig.11 : shows the Cole-Cole plot of a sample with CFP compared to the Cole-Cole plot of a sample with calcium carbonate;

[0060] Fig.12 : is a SEM image of the fracture surface of the sample with CPF obtained from a 3-point bending test, which shows the penetration of the polymer matrix into the pores of the CPF particles;

[0061] Fig.13 : is a SEM image of a CPF particle having pores extending along first and second mutually transverse directions;

[0062] Fig.14 : Graph showing the specific stiffness of thermoplastic materials filled with CPFs of different SSAs;

[0063] Fig.15 : Graph showing the fracture stress of thermoplastic material filled with CPF of different SSA;

[0064] Fig.16 :The figure shows the difference between the samples filled with CPF only or CaCO only. 3 Compared with thermoplastic materials filled with CPF and CaCO 3 The breaking stress of the thermoplastic material of the mixture.

[0065] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] Rigid decorative surface coverings (e.g., LVT) have many advantages (easy installation, suitable for renovation, including uneven subfloors, water tightness, ...). The core layer of those products can be quite thick (e.g., 2 mm-8 mm) and is usually semi-rigid or rigid (stiffness ranges from 0.5 GPa-2 GPa and 2 GPa-10 GPa (or more), respectively). Usually, filled PVC is used as thermoplastic material for the core layer, but there is also a growing demand for alternatives to PVC (compliance with some local regulations, concerns about PVC in certain regions, etc.).

[0067] Figure 1 A decorative surface covering tile 10 according to an embodiment of the present invention is shown. The tile 10 may be, for example, a rigid premium vinyl tile (LVT). The tile 10 may have a top surface 12, a bottom surface 14, and at least four side edges. Figure 1 The first edge 16 and the complementarily shaped second edge 18 are shown in more detail. The first edge 16 may include a first locking profile ("male profile") characterized by a tongue 20, and the second edge 18 may include a second locking profile ("female profile") characterized by a groove 22. The first locking profile and the second locking profile may be complementarily configured to mechanically engage and interlock with a second connection profile and a first connection profile of another tile of the same type, respectively. Specifically, the tongue 20 and the groove 22 may be complementarily shaped so as to achieve a tongue and groove connection between adjacent tiles. The groove 22 may be defined at its bottom by a base 24.

[0068] The brick 10 may have a layered structure and include a core layer 26, a decorative layer 27 disposed on the core layer 26, and a transparent or translucent wear layer 28. The core layer 26 may be rigid. The decorative layer 27 may include a printed substrate carrying one or more digitally printed ink layers. Alternatively, the decorative layer 27 may be printed directly on the core layer 26. As another possibility, the decorative layer 27 may be printed on the back side of the wear layer 28 before the wear layer 28 and the core layer 26 are laminated so as to sandwich the decorative layer 27. A backing layer 30, such as an elastic foam layer, a felt layer, or a wool layer, may be disposed on the bottom side 14 of the brick 10.

[0069] The core layer 26 may include multiple sublayers, such as one or more thermoplastic layers 26a, 26b, 26c and one or more reinforcing fiber layers 26d, 26e. The one or more fiber layers 26d, 26e may be optional and may include yarn, mesh or textiles made of reinforcing fibers, such as glass fiber, aramid fiber, ultra-high molecular weight polyethylene (UHMWPE) fiber, or similar fibers. The one or more fiber layers 26d, 26e may be embedded in or adjacent to one or more thermoplastic layers 26a, 26b, 26c. If the core layer 26 includes multiple thermoplastic sublayers 26a, 26b, 26c, these sublayers may be made of the same thermoplastic material or two or more thermoplastic materials of different compositions. However, it may be worth noting that, optionally, the core layer 26 may include the same thermoplastic material over its entire height.

[0070] The decorative surface covering tile 10 may have an overall height in the range from 2 mm to 10 mm, preferably in the range from 2.5 mm to 9 mm, and most preferably in the range from 2.5 mm to 8.5 mm.

[0071] The core layer 26 may have a deformation angle (α) of less than 10 degrees, preferably less than 7 degrees, more preferably less than 5 degrees, and most preferably less than 3 degrees, as measured by a deformation test. Figure 2 and Figure 3 For the deformation test illustrated in the figure, a 160 mm×450 mm rectangular sample 32 of the core layer 26 (including sublayers 26a, 26b, 26c, 26d, 26e in the illustrated embodiment) or another layer (component) is prepared. The sample 32 is then clamped in a horizontal cantilever state so as to obtain a 160 mm×300 mm rectangular protrusion of the sample. The protrusion is initially supported by a removable horizontal support over its entire length and width. The support is then removed so that the protrusion bends under its own weight. The deformation angle α is measured 30 seconds after removing the support 34, which prevents the protrusion from deforming under the influence of its own weight. The deformation angle α corresponds to the angle between the horizontal support plane 40 and the plane extending from the edge 36 of the support to the lowermost extremity 38 of the protrusion, from which the protrusion protrudes. The deformation test is carried out at ambient temperature and ambient pressure (at 23° C. and about 1000 hPa).

[0072] The core layer 26 comprises a thermoplastic material including a thermoplastic polymer (such as PVC or PVB), a filler and an additive. The filler comprises or consists of CPF and is dispersed in the thermoplastic polymer. The CPF has a carbon content of at least 70%, preferably at least 75%, more preferably at least 80% of the dry weight of the CPF, and a 5 m 2 / g to 500m 2 / g, preferably 40m 2 / g to 500m 2 / g specific surface area. CPF can have at least 10 -12 The isotope ratio 14 C / 12 C, preferably at least 1.2·10 -12 The isotope ratio 14 C / 12 C. It can be seen that CPF is mainly obtained from a renewable carbon source such as plant biomass. Preferably, from 80% to 100% by weight of the total carbon contained in the CPF is biochar. Preferably, the thermoplastic material as a whole (i.e. taking into account the carbon content of the polymer resin, any other filler and any additives) has a biochar / total carbon ratio of at least 25% by weight (corresponding to at least 2.5·10 -13 The isotope ratio 14 C / 12 C), more preferably a biochar / total carbon ratio of at least 40% by weight (corresponding to at least 4·10 -13 The isotope ratio 14 C / 12 C).

[0073] Preferably, CPF has the following physicochemical properties:

[0074] o The presence of multidirectional pores at least in the larger particles, especially in the particles with diameters larger than the D90 diameter of the filler,

[0075] o There are CPF particles with pores ranging in size from 1 μm to 30 μm,

[0076] ○Specific surface area of ​​CPF (ISO 9277:2010): 5m 2 / g to 500m 2 / g,

[0077] ○D50 diameter of CPF (ISO 13322-2:2021): 1μm-1000μm,

[0078] ○ Aspect ratio: 0.3-0.7 of CPF,

[0079] ○Carbon content of CPF (DIN 51732:2014): 80%-95%,

[0080] ○ H / C of CPF (determined by elemental composition analysis of particles using CHNS analyzer according to standard ASTM E777, 778): 0.1-0.5,

[0081] ○ O / C of CPF (determined by elemental composition analysis of the particles with the aid of a CHNS analyzer according to standards ASTM E777, 778): 0.01-0.15.

[0082] According to a first preferred embodiment, at least one of the core layers comprises a thermoplastic material comprising from 15 to 150 parts of CPF and up to 20 parts of additives (one or more stabilizers, one or more lubricants, one or more compatibilizers, one or more processing aids, etc.) per 100 parts of thermoplastic polymer.

[0083] Examples of thermoplastic material compositions according to the first preferred embodiment are detailed in Table 1 below.

[0084]

[0085] In Examples EX1-EX6 and EX7-EX10 (see Table 3 below), PVC is a suspension PVC from Inovyn with a particle size of 5 μm-200 μm and a K value of 67. Stabilizer is a one-pack Ca / Zn stabilizer from Reagens. Processing aids are acrylic acid-based additives produced by Arkema. External and internal lubricants include one or more polyolefin waxes from Wiwax and stearin from Brenntag. CPF1, CPF2 and CPF3 are samples of pyrolyzed biomass from different sources.

[0086] The physicochemical properties of CPF1, CPF2 and CPF3 (dry state) are indicated in Table 2:

[0087]

[0088] The particle size and aspect ratio of CPF1-CPF3 were characterized by a CAMSIZER X2 device from Microtrac MRB based on dynamic image analysis (ISO 13322-2:2021). The CaCO used in the comparative examples (CEX1, CEX2, see Table 3 below) 3 The filler has a median particle size (D50 diameter) of 5.9 μm, 4 μm 2 / g SSA and an aspect ratio of 0.75. These properties were determined using the same analyzers as for CPF.

[0089] The porosity of the CPF samples was characterized by Brewer-Emmett-Teller (BET) analysis (DIN 66137 / DIN ISO 9277) using nitrogen. This method determines the amount of nitrogen adsorbed on the surface at a given pressure, which provides a direct value for the specific surface area (SSA). A larger SSA indicates a more pronounced porous morphology.

[0090] The CPF samples were subjected to a complementary analysis by Fourier transform infrared spectroscopy (FT-IR) to determine their surface functional groups. FT-IR spectroscopy revealed (see Figure 4 ) There are -OH hydroxyl groups (connected to moisture) unique to benzene rings, aromatic rings (C=C) and aliphatic groups (CH), as well as carbonyl groups (C=O) in the carbon structure of the filler. The carbon nature and polar groups of the filler achieve hydrogen bonding with the polar structure of PVC.

[0091] Scanning electron microscopy (SEM) was used to reveal the porous nature of the CPF samples (see Fig.13 ). Note that the larger particles have pores extending in a first direction and a second direction, the second direction being transverse to the first direction (see Fig.13 The pore sizes range from 1 μm to 30 μm. The CPF samples with higher SSA contain more pores.

[0092] According to a second preferred embodiment, at least one of the core layers comprises a thermoplastic material comprising from 15 to 100 parts of CPF as a first filler, from 15 to 100 parts of one or more additional mineral fillers and up to 20 parts of additives per 100 parts of thermoplastic polymer.

[0093] Examples of thermoplastic material compositions according to the second preferred embodiment and comparative examples are detailed in Table 3 below.

[0094]

[0095] In Examples EX11 and CEX3, the polypropylene (PP) portion is a mixture (50 / 50) of Moplen (trademark) EP300M and Moplen (trademark) EH400H from LyonDellBasell. The coupling agent is Licocene (trademark) PP MA 7452 from Clariant. The talc is Luzenac (trademark) ST30 from Imerys. The lubricant package includes stearic acid and glycerides (e.g., Loxiol (trademark) EP55 from Emery Oleochemicals). The stabilizer package includes a blend of Irganox (trademark) 1010 from BASF and Irgafos (trademark) 168 from BASF. Examples EX11 and CEX3 are prepared to maintain the volume fraction (vol%) of the filler.

[0096] The different thermoplastic composites of Example EX1-Example EX10 and Comparative Examples CEX1, CEX2 are obtained by first dry blending the ingredients at 115°C ± 5°C during 10min ± 2min (see Table 1 and Table 3), and then extruding the mixed product by a counter-rotating twin (parallel screw) extrusion process in an extruder equipped with a vacuum pump to extract the inherent moisture of CPF. The process conditions include a rotation speed (revolutions per minute) of 120rpm ± 20rpm and a process temperature of 190°C ± 10°C. The thermoplastic composites of Example EX11 and Comparative Example CEX3 are extruded in a twin-screw co-rotating extruder equipped with a vacuum pump to extract the inherent moisture of the CPF filler. The melt temperature is about 210°C.

[0097] Table 4 below indicates the volume fraction of fillers in various Examples and Comparative Examples:

[0098]

[0099] Due to the low density of CPF (1.35g / cm 3 -1.4g / cm 3 ), when compared with a standard CaCO filled with approximately the same volume fraction of filler 3 The overall density of the thermoplastic material containing CPF as a filler is reduced when compared to the thermoplastic material.

[0100] Thermoplastic materials with different volume fractions of fillers were tested by three-point bending measurements. The first parameter to be evaluated was the stiffness to weight ratio or specific stiffness, which is a relevant parameter for classifying the best structures with minimum weight and low deflection. The results are in Figure 5 (a) and Figure 5(b) is depicted. For both fillers, it is observed that the specific stiffness increases with increasing volume fraction of the filler. An attempt to describe this increase is made with the aid of a rule of mixture:

[0101] E c / ρ c =φ f E f / ρ f +(1-φ f )E m / ρ m , (Equation 1)

[0102] Among them, φ f is the volume fraction of the filler, ρ c , f and ρ m are the density of the thermoplastic material (composite), the density of the filler and the density of the matrix (polymer resin), respectively, and E c 、E f and E m are the stiffness of the thermoplastic material (composite), the stiffness of the filler and the stiffness of the matrix (polymer resin). For illustration, it can be assumed that the PVC matrix, CPF and CaCO 3 The moduli of the fillers are 2.1 GPa, 5 GPa, and 68 GPa, respectively. In order for the mixing law to be accurate, three assumptions need to be met:

[0103] i) rigid (non-deformable) fillers,

[0104] ii) uniform dispersion and distribution of fillers, and

[0105] iii) Perfect polymer-filler adhesion.

[0106] When observing Figure 5 When looking at the results in (a) for thermoplastics containing CPF, the law of mixtures shows good agreement with the experimental data up to 25 vol.% filler. Above this level, the experimental values ​​of specific stiffness are higher than those predicted by the law of mixtures. This may indicate that there is good polymer-filler interaction / adhesion and that an interface (i.e., a thin (e.g., about 0.1 μm to about 1.0 μm) region between the filler surface and the bulk polymer matrix whose mechanical properties differ from those of the bulk polymer) is generated. For CaCO filled 3 Thermoplastic materials, Figure 5 (b) shows that the law of mixtures overestimates the specific stiffness when compared to experimental data. This may be due to poor filler distribution, and non-existent or poor polymer-filler interaction / adhesion.

[0107] Figure 6 The evaluation of the fracture strain of carbon-based porous filler and calcium carbonate at bending loads of different volume fractions is presented. For these two thermoplastic materials, the fracture strain decreases with the increase of filler content. In the volume fraction range studied, the thermoplastic material filled with carbon shows the lowest fracture strain. However, the rate of reduction of fracture strain in the composite filled with porous carbon (power-like) is lower than the rate of reduction of fracture strain in the composite filled with calcium carbonate (linear). This may be due to better attachment / interaction between porous carbon filler and PVC, which limits the movement of polymer chains to adapt to load (lower fracture strain), but requires greater stress to cause fracture.

[0108] The ultimate stress value determined by three-point bending is Figure 7 The fracture stress of thermoplastics filled with CPF is higher than that filled with CaCO 3 This indicates that the stress transfer between CPF and polymer matrix is ​​better than that of standard CaCO 3 For a given volume fraction of filler, a 20% increase in the ultimate stress of the CPF composites was observed.

[0109] exist Figure 8 The evolution of the loss factor, i.e. the ratio between the loss modulus E” and the storage modulus E’, as a function of temperature is shown for thermoplastic materials with different CFP contents. This parameter is a direct indicator of the internal dissipation of the material associated with the coordinated polymer chain motion. The higher the E” / E’, the higher the internal dissipation and, therefore, the smaller the polymer-filler interaction. When the volume fraction of CPF increases, the amplitude of E” / E’ decreases. This indicates that the polymer chains of PVC interact with the CPF filler.

[0110] Fig. 9 The temperature-dependent loss factors of thermoplastic materials containing either calcium carbonate or CPF were compared. 3 The thermoplastic with CPF shows a 20% lower E" / E' amplitude. This indicates that the polymer-filler interaction between PVC and CPF is stronger than that between PVC and CaCO. 3 The polymer-filler interaction is better.

[0111] The viscoelastic behavior of thermoplastics can be further studied using the Cole-Cole method, where the loss modulus is plotted as a function of the storage modulus. Fig.10A homogeneous composite system, i.e. one with well-distributed and dispersed fillers, exhibits a semicircular Cole-Cole plot. This is the case for the thermoplastic materials of Examples EX1-EX5. 3 For the thermoplastic materials of Comparative Examples CEX1 to Comparative Examples CEX2, the shape of the Cole-Cole diagram is imperfect (see Fig.11 ), which indicates an uneven distribution of the filler. Therefore, under the same processing conditions, the CPF filler can be better distributed in the polymer matrix.

[0112] The presence of fillers can constrain polymer chains, providing mechanical reinforcement. The level of entanglement in a polymer composite can be used as an indicator of the level of polymer-filler interaction through adsorption. Using the theory of rubber elasticity, the density of entanglements in a polymer system, v e , can be determined as follows:

[0113]

[0114] Among them, E (c_120℃) 、N A , R and T are the storage modulus, Avogadro number, gas constant and absolute temperature of the thermoplastic material in the rubbery plateau, respectively.

[0115] The mechanical reinforcement efficiency of the filler, r, can be evaluated using the Einstein equation:

[0116] r=(E c_120℃ / E m_120℃ -1) / φ f (Equation 3)

[0117] Where E (m_120℃) is the storage modulus of the polymer in the rubber platform.

[0118] Table 5 shows the effect of filler content (by volume) on the viscoelasticity. The results are derived from dynamic mechanical thermal analysis (DMA) performed on different samples according to the Examples and Comparative Examples.

[0119]

[0120] As the filler content increases, the density of the entanglements and the degree of reinforcement increase. This increase is higher when CPF is added. In fact, when compared with equal volumes of filler, the thermoplastic with CPF is stronger than that with CaCO 3The thermoplastic materials showed higher entanglement and reinforcement levels, indicating that the interaction between thermoplastic polymer and CPF is stronger than that between thermoplastic polymer and CaCO. 3 The interaction is stronger.

[0121] exist Fig.12 SEM images of the fracture surface of the sample with CPF obtained from the 3-point bending test are presented in. The images reveal that the polymer penetrates into the pores of the CPF during the extrusion process, thereby achieving mechanical interlocking.

[0122] The above results suggest that the mechanical enhancement of thermoplastics with CPFs may be a result of: i) the stiffness of the filler (related to the carbon content), ii) the mechanical interlocking created by the polymer filling the filler pores, and iii) adsorption and surface reactions related to the affinity of the polymer for CPFs or functional groups on the CPF surface (measured by FT-IR).

[0123] exist Fig.14 The specific stiffness of thermoplastic materials filled with CPFs of different SSAs is depicted in Figure 1. The figure shows that the specific stiffness increases with the specific surface area. The same trend can be observed for the bending stress at fracture ( Fig.15 ). In fact, the increase in SSA may be related to the higher number of pores, which serve as interlocking sites between filler and polymer, increasing stress transfer.

[0124] The effect of SSA on viscoelasticity is shown in Table 6. The results are derived from DMA using Eq. 2 and Eq. 3.

[0125]

[0126] As can be observed, the magnitude of E" / E' decreases as the SSA of the filler increases, while the density of entanglements and the reinforcement efficiency increase. This can be explained by the higher level of interaction obtained when increasing the number of pores of the filler.

[0127] like Fig.16 As shown in the figure, when compared with the 3 When compared to similar thermoplastic compounds as fillers, CPF replaces part of the volume of CaCO 3 Fillers can improve the breaking stress of thermoplastic compounds.

[0128] With regard to PVC thermoplastic composites, it has been shown in the PP thermoplastic composite according to EX11 that replacing part of the conventional mineral fillers with CPF fillers in the PP matrix leads to an improved reinforcement effect, wherein the breaking stress is increased (+25%) compared to comparative example CEX3. The density in example EX11 is also reduced compared to comparative example CEX3.

[0129] The increased mechanical reinforcement provided by CPF may be beneficial in structural layers of decorative surface coverings such as flooring. Therefore, particularly preferred aspects of the present invention relate to the use of CPF in the rigid layer of flooring such as LVT click products, and floor tiles comprising one or more core layers of thermoplastic material containing CPF as described herein. Such core layers may be single-layer (preferably made by extrusion and agglomeration), multi-layer (e.g. obtained by coextrusion), dense or foamed. According to a specific embodiment, the core layer is a foamed single layer. A core layer comprising a dense (unfoamed) outer layer sandwiching a foamed inner layer may be a particularly preferred option for floor tiles, especially for relatively lightweight, rigid LVT products with interconnecting profiles along the lateral edges.

[0130] Floor tiles with connecting profiles according to various embodiments of the invention show good fatigue performance in the Castorchair test (ISO 4918:2016 revised in 2018). The results show that it is possible to reduce the core thickness of the floor component by about 10% when compared to floor tiles currently on the market.

[0131] Therefore, compared with conventional fillers such as CaCO 3 The decorative surface covering according to the invention can have a significantly reduced ecological impact (in particular significantly reduced CO 2 Footprint). Furthermore, as shown by the inventors, the use of CPFs with specific physicochemical properties leads to improved mechanical properties, so that the thickness of the decorative floor covering can be reduced, leading to a further reduction of the ecological impact.

[0132] Although specific embodiments have been described in detail herein, it will be appreciated by those skilled in the art that various modifications and alternatives to these details may be developed based on the overall teachings of the present disclosure. Therefore, the specific arrangements disclosed are meant to be illustrative only and are not intended to limit the scope of the invention, which will be afforded the full scope of the appended claims and any and all equivalents thereof.

Claims

1. A decorative surface covering, such as a floor covering, a wall covering or a ceiling covering, comprising a core layer, wherein the core layer comprises as a matrix a thermoplastic material comprising one or more thermoplastic polymers and a carbon-based porous filler (CPF) dispersed in the matrix, wherein the CPF has a carbon content of at least 70%, preferably at least 75%, more preferably at least 80% by dry weight and a 5 m / s thermal conductivity measured according to standard ISO 9277:2010 (Bruer-Emmett-Teller (BET) method). 2 / g to 500m 2 / g, preferably 20m 2 / g to 450m 2 / g, more preferably 40m 2 / g to 400m 2 / g specific surface area.

2. The decorative surface covering of claim 1, wherein the CPF has a -12 The isotope ratio 14 C / 12 C, preferably at least 1.2·10 -12 The isotope ratio 14 C / 12 C.

3. A decorative surface covering according to claim 1 or 2, wherein the CPF comprises biochar.

4. A decorative surface covering according to any one of claims 1 to 3, wherein the thermoplastic material comprises dispersed therein an additional filler selected from the group consisting of ground limestone, dolomite, calcium carbonate, zeolites, magnesium carbonate, chalk, layered silicates such as talc, glass particles and aluminium trihydroxide.

5. A decorative surface covering according to any one of claims 1 to 4, wherein the thermoplastic material comprises from 2 to 70% by weight, preferably from 3 to 60% by weight, more preferably from 5 to 40% by weight of the CPF.

6. A decorative surface covering according to any one of claims 1 to 5, wherein the thermoplastic material has a total filler content of from 5 to 70% by weight, preferably from 10 to 65% by weight, more preferably from 10 to 60% by weight.

7. The decorative surface covering according to any one of claims 1 to 6, wherein the CPF has a D50 diameter in the range from 1 μm to 50000 μm, preferably in the range from 2 μm to 5000 μm, more preferably in the range from 5 μm to 1000 μm, still more preferably in the range from 15 μm to 500 μm, and most preferably in the range from 30 μm to 100 μm.

8. A decorative surface covering according to any one of claims 1 to 7, wherein the CPF comprises particles anchored in a thermoplastic polymer matrix by mechanical interlocking caused by the thermoplastic polymer penetrating into the pores of the particles.

9. A decorative surface covering according to any one of claims 1 to 8, wherein the CPF comprises particles having multi-directional porosity, ie particles having first pores extending in a first direction and second pores extending in a second lateral direction.

10. A decorative surface covering according to claim 8 or 9, wherein the CPF has pores with a pore size in the range from 0.5 to 30 μm, preferably in the range from 0.75 to 20 μm and more preferably in the range from 1 to 10 μm.

11. A decorative surface covering according to any one of claims 1 to 10, comprising a surface covering tile comprising a decorative layer, a wear layer and optionally a backing layer.

12. Decorative surface covering according to claim 11, wherein the decorative layer comprises a printed substrate bearing a print having a hiding power H10 measured according to standard ISO 6504-3:2019 of at least 80%, preferably at least 90%.

13. A decorative surface covering according to any one of claims 1 to 12, wherein the core layer is a rigid core layer, the rigid core layer having a deformation angle of less than 7 degrees, more preferably less than 5 degrees, most preferably less than 3 degrees, the deformation angle being measured at 23°C for a rectangular core layer sample of dimensions 160mm×450mm, the rectangular core layer sample being clamped in a horizontal cantilever state so as to obtain a protrusion of the sample of 160mm×300mm, the deformation angle being measured 30 seconds after removing a support, which prevents the protrusion from deforming under the influence of its own weight.

14. A decorative surface covering according to any one of claims 1 to 13, comprising a floor tile, the floor tile comprising a first locking connection along a first edge and a second locking connection along a second edge, the first locking connection and the second locking connection having complementary profiles so that the floor tile can be interlocked with another floor tile by engaging the first locking connection or the second locking connection of the floor tile with the second locking connection or the first locking connection of another floor tile.

15. A decorative surface covering according to any one of claims 1 to 14, wherein the one or more thermoplastic polymers comprises polyvinyl chloride, polypropylene or polyvinyl butyral, preferably recycled polyvinyl chloride, polypropylene or polyvinyl butyral.

16. A decorative surface covering according to any one of claims 1 to 15, wherein the core layer comprises a core layer assembly comprising at least two layers of different configurations.

17. A decorative surface covering according to claim 16, wherein the core assembly comprises three or more layers including two outer layers sandwiching one or more inner layers.

18. A decorative surface covering according to claim 17, wherein said two outer layers are unfoamed layers of said thermoplastic material.

19. A decorative surface covering according to claim 17 or 18, wherein said one or more inner layers comprise at least one foamed layer, said foamed layer optionally comprising as a matrix said thermoplastic material or another thermoplastic material comprising one or more thermoplastic polymers and dispersed in said matrix a carbon-based porous filler (CPF), said CPF having a carbon content of at least 70% of said dry weight and a 5 m / s density measured according to standard ISO 9277:2010 (Bruer-Emmett-Teller (BET) method). 2 / g to 500m 2 / g specific surface area.

20. A decorative surface covering according to claims 1, 2, 5 to 9, 11 and 13 to 15, for use in combination.

21. A decorative surface covering according to claims 4 and 16 to 20, for use in combination.

22. A process for producing a core layer of a decorative surface covering according to any one of claims 1 to 21, comprising the steps of: 1) 5m.s -1 Up to 85m.s -1 mixing a thermoplastic material comprising one or more thermoplastic polymers and a carbon-based porous filler (CPF) at a peripheral speed of 1000 rpm until the mixture of the thermoplastic material and the carbon-based porous filler (CPF) reaches a temperature of 95° C. to 125° C., and 2) extruding the mixture of thermoplastic material and carbon-based porous filler (CPF) at a temperature of at least 100° C. by using at least one screw with a speed of from 50 s -1 Up to 400s -1 The local maximum shear rate rotates.

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