Substrate sheet for decorative floor or wall covering

Abstract

Aspects of the present invention relate to a method for producing a substrate sheet for a decorative floor or wall covering (10), a method for producing a decorative floor or wall covering, and a decorative floor or wall covering (10). The method for producing the substrate sheet includes providing a first thermoplastic composition (S2) comprising recycled PVC particles, the first thermoplastic composition (S2) having a chromaticity. Additionally, the method includes (S6) blending a darkening agent into the first thermoplastic composition in order to obtain a first thermoplastic composition having a specific chromaticity. A second thermoplastic composition (S4) is also provided. The method further includes co-extruding (S8) the first thermoplastic composition having the specific chromaticity (S2) with the second composition (S4) in order to form an adjacent first co-extruded layer and second co-extruded layer. The first co-extruded layer is a support layer having the specific chromaticity and comprises the first thermoplastic composition (S2). The second co-extruded layer is a digitally printable layer and comprises the second thermoplastic composition (S4).

Description

Field of the Invention

[0001] The present invention relates to a method for producing a substrate sheet for a decorative floor or wall covering, a decorative floor or wall covering including the substrate sheet, and a method for producing a decorative floor or wall covering. Background of the Invention

[0003] Document EP 3 326 815 A1 teaches a method for forming a laminated structure of a plastic floor, the method comprising the following steps:

[0004] A. forming a substrate by using an extruder so as to integrally extrude the substrate, the substrate comprising at least two sheets, wherein the at least two sheets are a first sheet and a second sheet stacked together;

[0005] B. delivering a printed layer, wherein the printed layer is printed with a pattern and is delivered to a roller unit by using a second rolling mechanism and a second pressing mechanism;

[0006] C. conveying a wear-resistant layer, wherein the wear-resistant layer is conveyed to the roller unit by means of the second rolling mechanism and the second pressing mechanism of a roller conveyor; and

[0007] D. roll-compressing the substrate, the printed layer, and the wear-resistant layer together by means of the roller unit so as to form the plastic floor, and removing and cutting the plastic floor based on a desired size.

[0008] General Description

[0009] A first aspect of the present invention relates to a method for producing a substrate sheet for a decorative floor or wall covering. The method comprises: providing a first thermoplastic composition comprising recycled polyvinyl chloride (PVC) particles, the first thermoplastic composition having a chromaticity; and providing a second thermoplastic composition. The method further comprises blending a color intensifier into the first thermoplastic composition so as to obtain a first thermoplastic composition having a specific chromaticity. Co-extruding the first thermoplastic composition having the specific chromaticity with the second composition so as to form adjacent first and second co-extruded layers. The first co-extruded layer is a support layer having the specific chromaticity. The support layer comprises the first thermoplastic composition. The second co-extruded layer is a digitally printable layer. The digitally printable layer comprises the second thermoplastic composition. The blending of the color intensifier into the first thermoplastic composition is purposefully carried out to achieve a specific chromaticity, which is known (predetermined), i.e., the desired chromaticity. In other words, the specific chromaticity is the target parameter (specific target chromaticity) for blending the color intensifier.

[0010] As used herein, a thermoplastic composition is a plastic polymer composition that becomes flexible or moldable above a certain temperature and solidifies upon cooling.

[0011] Recycled PVC can be sourced from multiple sources (e.g., PVC products or PVC semi-finished products). As a result, the composition, color, chromaticity, geometry, size, physical and / or chemical properties of recycled PVC granules can vary greatly. Typically, the size of the PVC granules is less than 1000 μm, preferably less than 800 μm, and even more preferably less than 300 μm. The size of the PVC granules can be measured by a sieve.

[0012] As used herein, the color of an object is the property that gives the eye a different sensation due to the way it reflects or emits light (e.g., blue). Chromaticity is the relative darkness of a color (e.g., light blue, dark blue).

[0013] As used herein, a support layer is a layer that provides structural support (e.g., rigidity) to the substrate sheet and also to the finished decorative floor or wall covering.

[0014] As used herein, a digitally printable layer is preferably a substantially white layer, i.e., the luminance L* defined in the CIELAB color space is greater than 80, preferably greater than 85, and even more preferably greater than 90. The digitally printable layer preferably has a predetermined chromaticity that is lighter than a specific chromaticity of the first thermoplastic composition. According to one embodiment, the digitally printable layer has a surface energy included in the range between 15 mN / m and 60 mN / m, preferably in the range from 20 mN / m to 50 mN / m, and even more preferably in the range from 25 mN / m to 40 mN / m. The digitally printable layer can have a surface roughness R less than 0.5 μm, preferably less than 0.3 μm, and even more preferably less than 0.2 μm a . The digitally printable layer can have a surface roughness R less than 5 μm, preferably less than 3 μm, and even more preferably less than 2 μm z . The surface roughness is measured according to ISO4288:1996. According to one embodiment, the digitally printable layer has a glossiness value at 60° included in the range from 10 to 90, preferably in the range from 20 to 80, and even more preferably in the range from 25 to 75. The glossiness value is measured according to EN ISO 2813:2014. The opacity of the digitally printable layer can be greater than 90%, preferably greater than 95%, and even more preferably greater than 97%. The opacity of the digitally printable layer is measured according to DIN 53146. The opacity O is the ratio between the reflectance R0 and the reflectance R ∞ : O = R0 / R ∞ , where the reflectance R0 is the reflectance of the digitally printable layer on pure black, and the reflectance R ∞is the reflectance of the same digitally printable layer on a stack of the same digitally printable layers thick enough to be opaque. DIN 53145 defines the requirements for determining the reflectance R0 and the reflectance R ∞ necessary conditions.

[0015] The first thermoplastic composition is preferably based on PVC. The first thermoplastic composition can be a blend comprising virgin PVC and recycled PVC. As an alternative or addition to virgin PVC, the first thermoplastic composition can comprise the following virgin polymers: PE (polyethylene, including LDPE, HDPE, etc.), ABS (acrylonitrile butadiene styrene), PP (polypropylene), polyvinyl acetate (PVA), polyvinyl alcohol (PVOH), other vinyl and vinylidene (co)polymers, polystyrene (PS), styrene copolymers, propylene copolymers, polyesters, acrylic resins, polyamides, polycarbonate (PC), polyimide, polysulfone or combinations thereof. The first thermoplastic composition is preferably provided as suspension PVC (S-PVC) comprising recycled PVC particles.

[0016] As used herein, a "darkening agent" is a substance that imparts a deeper color shade to the first thermoplastic composition. Darkening agents are typically used in various forms, such as discrete particles, dispersions and / or solutions. Darkening agents can include pigments (organic or inorganic) and / or dyes. Pigments are preferred. Exemplary pigments include carbon black, iron oxide black, bone black, lamp black, ivory black. Carbon black is preferred.

[0017] It will be appreciated that the present invention allows for the production of more versatile substrate sheets without having to increase their production costs. In fact, the use of recycled PVC allows for a proportional reduction in the amount of virgin material in the finished product. The inventors have found that accurately controlling the color shade of the support layer (comprising recycled PVC) located beneath the digitally printable layer and the overlying digitally printed ornamentation greatly improves the constancy of the quality of the final decorative floor or wall covering (e.g., over several production batches). For example, two different final decorative floor or wall coverings having the same ornamentation and digitally printable layer can look different (e.g., darker, lighter) overall or locally because the recycled PVC is sourced from different sources and thus has, for example, different compositions, colors, color shades. Additionally, the digitally printed ornamentation provides great flexibility in terms of the printed pattern, especially when compared to the calendering of the printed layer as proposed in EP 3 326 815 A1. By configuring the digital printer, the pattern can be easily changed even during operation.

[0018] Preferably, the step of admixing the darkening agent is carried out such that the pigments are tightly packed within the support layer so that they cannot move relative to each other.

[0019] According to one embodiment, the step of blending the darkening agent includes adding the darkening agent to a first thermoplastic composition to obtain a first thermoplastic composition having a deeper color shade, and comparing the deeper color shade with a specific color shade. Based on the comparison, if necessary, the above steps are repeated until a first thermoplastic composition having the specific color shade is obtained. In one embodiment, the step of comparing the deeper color shade with the specific color shade is carried out as follows. A sample of the first thermoplastic composition having the deeper color shade is compared with a reference sample having the specific color shade. If the deeper color shade and the specific color shade do not match within certain limits, the deeper color shade is considered to correspond to the specific color shade. Accordingly, the steps of adding the darkening agent and comparing the obtained deeper color shade are not repeated. If the mismatch is greater than certain limits, the deeper color shade is considered not to correspond to the specific color shade. The above steps are repeated. In other words, a matching tolerance for the specific color shade can be used to determine whether the above steps should be repeated. As used herein, a color shade that lies within the matching tolerance of the specific color shade is said to match the specific color shade within the matching tolerance. In a second embodiment, a plurality of samples of the first thermoplastic composition can be obtained, each of which has a different deeper color shade (obtained by adding different amounts of the darkening agent). Each of the samples is compared with a reference sample having the specific color shade. A sample having a deeper color shade that matches the specific color shade within the said matching tolerance is selected. If no sample matches within the said tolerance, the above steps are repeated for a plurality of other samples having deeper color shades that are included between the two samples with the closest color shades. One of the two selected closest samples has a color shade lighter than the specific color shade, while the other of the two closest samples has a color shade deeper than the specific color shade. At the end of the blending step, the amount of the darkening agent added to obtain the first thermoplastic composition having the specific color shade is known.

[0020] Preferably, the matching tolerance is set such that the specific color shade "s" (in the CIELAB color space ) and the deeper color shade "d" (in the CIELAB color space ) differ from each other by at most a ΔE value of 5, preferably at most a ΔE value of 3, and even more preferably at most a ΔE value of 1, where ΔE is calculated according to .

[0021] According to one embodiment, the step of blending the darkening agent into the first thermoplastic composition is implemented as a negative feedback loop in order to obtain a first thermoplastic composition having a specific color shade by adding the darkening agent to the first thermoplastic composition. The amount of the darkening agent added to the first thermoplastic composition is determined by the negative feedback loop such that the color shade of the first thermoplastic composition becomes increasingly closer to the specific color shade after each iteration until the color shade of the first thermoplastic composition matches the specific color shade within the matching tolerance.

[0022] Several methods for determining the colorimetry of a sample can be envisaged. For example, a spectrophotometer can be used. Alternatively or additionally, a calibrated camera can be used to take a digital photograph of the sample in a controlled environment (e.g., lighting).

[0023] The first thermoplastic composition may comprise from 10 wt% to 50 wt%, preferably from 15 wt% to 35 wt%, more preferably from 17 wt% to 32 wt% of recycled PVC particles.

[0024] The first thermoplastic composition may comprise from 30 wt% to 70 wt%, preferably from 35 wt% to 65 wt%, more preferably from 45 wt% to 55 wt% of one or more fillers.

[0025] The one or more fillers may be one or more organic and / or inorganic fillers, such as selected from the group consisting of: bauxite, talc, mica, dolomite, barite, kaolin, silica, glass, calcium carbonate, chalk, colloidal or amorphous silica, magnesia, clay or any combination thereof. Examples of organic fillers are cellulose or polymer fibers (e.g., wood flour or sawdust).

[0026] The first thermoplastic composition may comprise from 0.01 wt% to 0.1 wt%, preferably from 0.02 wt% to 0.075 wt%, more preferably from 0.025 wt% to 0.05 wt% of a darkening agent.

[0027] The second coextruded layer may have a thickness included in the range from 0.1 mm to 5 mm, preferably in the range from 0.1 mm to 3 mm, more preferably in the range from 0.1 mm to 1 mm, even more preferably in the range from 0.1 mm to 0.3 mm.

[0028] The first coextruded layer may have a thickness included in the range from 2 mm to 15 mm, preferably in the range from 3 mm to 12 mm, more preferably in the range from 4 mm to 10 mm.

[0029] A second aspect of the present invention relates to a method for producing a decorative floor or wall covering. The method comprises: providing a substrate sheet according to the first aspect of the present invention; and digitally printing a decoration on a digitally printable layer.

[0030] As used herein, digital printing refers to a method for printing a digital image on a substrate sheet, more specifically on a digitally printable layer. Examples of digital printing methods include inkjet printing and laser printing. In an inkjet printing method, an image is formed by ejecting droplets of ink onto the digitally printable layer. The ink may include pigments and / or dyes as colorants.

[0031] The ornament is preferably printed directly on the digitally printable layer.

[0032] The method may include applying a wear-resistant layer on the digitally printed ornament, preferably directly on the digitally printed ornament. The wear-resistant layer may be translucent or transparent.

[0033] As used herein, a transparent layer is a layer that allows light transmission to be substantially unaffected. A translucent layer partially allows light transmission but does not allow clear viewing of objects through the layer.

[0034] The method may include applying a polyurethane-based top layer. According to one embodiment, the polyurethane-based top layer is applied on the wear-resistant layer, preferably directly on the wear-resistant layer. The polyurethane-based top layer may be obtained from a moisture-curable composition, a radiation-curable (e.g., UV-curable) composition, or a 100% solid composition. 100% solid means a composition that is substantially free of non-reactive solvents (e.g., free of water or other (organic) solvents). The polyurethane-based top layer may be translucent or transparent. The polyurethane-based top layer may be a polyurethane top layer.

[0035] The wear-resistant layer and the polyurethane-based top layer may be applied by any known technique in the art, such as calendering, extrusion coating, spreading the composition, and curing the composition. The spreading of the composition may be achieved, for example, by smooth roll coating, curtain coating, air knife coating, spraying, and combinations thereof. The curing of the composition may be achieved, for example, by UV curing for UV-curable compositions, flash evaporation for water-based suspensions.

[0036] Preferably, the ornament has a thickness included in the range from 0.05 mm to 1 mm, preferably in the range from 0.1 mm to 0.8 mm, more preferably in the range from 0.2 mm to 0.7 mm. According to one embodiment, the ornament is digitally printed on the digitally printable layer according to a pattern. According to one embodiment, the digitally printable layer is not completely covered by the ornament. In other words, the pattern includes one or more voids. In the case of a patterned ornament, the area where the ornament is digitally printed may have the thickness as described above. The ornament may be one-dimensionally, two-dimensionally, or three-dimensionally patterned. The ornament may be translucent.

[0037] The third aspect of the present invention relates to a decorative floor or wall covering obtained by the method according to the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] By way of example, preferred, non-limiting embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0039] Figure 1: is a flowchart of a method for producing a multi-layer decorative floor or wall covering according to a preferred embodiment of the present invention;

[0040] Figure 2 : is a flowchart of a process for obtaining a thermoplastic composition having a specific chromaticity;

[0041] Figure 3 : is a cross-sectional view of a part of a multi-layer decorative floor or wall covering according to an embodiment of the present invention; and

[0042] Figure 4 : is a cross-sectional view of a part of a multi-layer decorative floor or wall covering according to another embodiment of the present invention.

[0043] The reader should note the fact that the drawings are not drawn to scale. In addition, for clarity, the ratios between height, length and / or width may not be correctly represented. Detailed Description

[0044] Figure 1 Shows a method for producing a multi-layer decorative floor or wall covering according to a preferred embodiment of the present invention. The method includes providing (S2) a first thermoplastic composition comprising recycled PVC particles and providing a second thermoplastic composition, and these two thermoplastic compositions will be co-extruded at a later stage so as to form adjacent first and second co-extruded layers.

[0045] The first thermoplastic composition further comprises virgin PVC (e.g., suspension PVC (S-PVC), micro-suspension PVC, emulsion PVC) and fillers. Additionally, the first thermoplastic composition may comprise one or more additives such as impact modifiers, processing aids, (oxidized) polyethylene wax (PE wax) and stearic acid. The first thermoplastic composition comprises from 10 wt% to 50 wt%, preferably from 15 wt% to 35 wt%, more preferably from 17 wt% to 32 wt% of recycled PVC particles. The ratio of virgin PVC to recycled PVC is included in the range from 0.5 to 1.5, preferably in the range from 0.75 to 1.25. The first thermoplastic composition comprises from 30 wt% to 70 wt%, preferably from 35 wt% to 65 wt%, more preferably from 45 wt% to 55 wt% of one or more fillers.

[0046] The PVC particles can be derived from different products (e.g., recycled floor or wall coverings, pipes, furniture, etc.). Therefore, the chemical composition and physical properties (e.g., plasticizer content, chromaticity, additive content, etc.) of such PVC particles can be accurately controlled only to the extent that the mixture of recycled PVC particles is exactly known. Additionally, since the first thermoplastic composition is to be co-extruded, the chemical composition of the PVC particles can vary from batch to batch.

[0047] In the next step (S6), a deepening agent is added to the first thermoplastic composition so as to obtain a first thermoplastic composition having a specific chromaticity. Thus, at the end of step S6, the first thermoplastic composition has a specific chromaticity regardless of the chemical composition of the PVC particles.

[0048] Then the first thermoplastic composition and the second thermoplastic composition are co-extruded (S8) so as to form an adjacent first co-extruded layer and second co-extruded layer. The first co-extruded layer is a support layer comprising the first thermoplastic composition. The second co-extruded layer is a substantially white digitally printable layer. The second co-extruded layer comprises a second thermoplastic composition.

[0049] The first co-extruded layer has a thickness included in the interval from 2 mm to 15 mm, preferably in the interval from 3 mm to 12 mm, more preferably in the interval from 4 mm to 10 mm. The second co-extruded layer has a thickness included in the interval from 0.1 mm to 5 mm, preferably in the interval from 0.1 mm to 3 mm, more preferably in the interval from 0.1 mm to 1 mm, even more preferably in the interval from 0.1 mm to 0.3 mm. It should be noted that it is generally desirable that the thickness of the support layer is greater than the thickness of the digitally printable layer. In fact, the production cost of a digitally printable layer having only virgin PVC and no recycled PVC is generally much higher than the production cost of the support layer. For example, the ratio of the thickness of the digitally printable layer to the thickness of the support layer can be included in the interval between 0.05 and 0.5, preferably in the interval between 0.1 and 0.4, and more preferably in the interval between 0.15 and 0.3. At the end of step S8, a substrate sheet is produced.

[0050] The method includes digitally printing (S10) a decoration directly on the digitally printable layer of the substrate sheet. The digital printing can be achieved by inkjet printing or laser printing or a combination of both. The decoration can be in the form of a layer, preferably a layer having a uniform thickness, or a pattern. The pattern can represent a natural design, such as wood or stone. The decorative pattern can also be a whimsical design or a photograph.

[0051] Subsequently, a wear-resistant layer can be applied (step S12) on the decoration, followed by applying a polyurethane top layer (step S14) on the wear-resistant layer. One layer or other layers can be omitted.

[0052] The wear-resistant layer and the polyurethane layer can be applied, for example, by calendering, hot pressing or any other technique known in the art.

[0053] The wear-resistant layer and the polyurethane are transparent or translucent so that the decoration can be seen when looking at the top of the decorative floor or wall covering.

[0054] It will be appreciated that accurately controlling the chromaticity of the support layer allows for providing ornamentations with little difference in chromaticity to decorative floor or wall coverings containing recycled PVC, even when the recycled PVC is sourced from different origins. This is especially true for very thin digitally printable layers. In other words, deepening the support layer allows for providing a digitally printable white layer with improved digital printing consistency, which in turn allows for providing decorative floor or wall coverings with little difference in chromaticity between co-extrusion batches.

[0055] Reference Figure 2 describes a method for obtaining a first thermoplastic composition having a specific chromaticity according to an embodiment of the present invention.

[0056] In step S22, the chromaticity of the first thermoplastic composition (S2) is determined. This step can be carried out in various ways. For example, a spectrophotometer can be used to determine the chromaticity of the first thermoplastic composition. Additionally or alternatively, a calibrated digital camera can be used to take a digital photo of the composition under controlled lighting. The digital image is then processed to determine the chromaticity of the first thermoplastic composition, specifically to determine the triple in the CIELAB color space of the first thermoplastic composition Preferably, a matching tolerance is set such that a specific chromaticity "s" (in the CIELAB color space ) and a deeper chromaticity "d" (in the CIELAB color space ) differ by at most a ΔE value of 5, preferably at most a ΔE value of 3, more preferably at most a ΔE value of 1, where ΔE is calculated according to .

[0057] Then the determined chromaticity of the first thermoplastic composition is compared with a specific chromaticity (S24) having a triple in the CIELAB color space . In this step, it is determined whether the chromaticity of the first thermoplastic composition matches the specific chromaticity within the matching tolerance. Specifically, the distance ΔE between the chromaticity of the first thermoplastic composition and the specific chromaticity is determined according to . The matching tolerance ΔE 最大 indicates the maximum value of ΔE used to determine whether the first thermoplastic composition matches the specific chromaticity within the matching tolerance. The matching tolerance ΔE 最大 can be equal to 5, preferably equal to 3, even more preferably equal to 1. If the chromaticity matches the matching tolerance (i.e., ΔE ≤ ΔE 最大 ), a first thermoplastic composition having the specific chromaticity is obtained. If this is not the case (i.e., ΔE > ΔE 最大) Then, the controller (S26) instructs the actuator to add a darkening agent to the thermoplastic composition (S28). The thermoplastic composition now has a darker chromaticity than before. Steps S22 to S26 are repeated until the chromaticity of the thermoplastic composition matches the specific chromaticity within the matching tolerance.

[0058] It should be noted that the process defined in steps S22 to S28 can be performed on a sample taken from the first thermoplastic composition. The controller stores the amount of the darkening agent required to obtain the first thermoplastic composition having a specific chromaticity. The proportion of the darkening agent to be added to the first thermoplastic composition itself is known.

[0059] The method for obtaining the first thermoplastic composition having a specific chromaticity can also be carried out in a different manner. For example, a plurality of samples can be extracted from the first thermoplastic composition. Different amounts of the darkening agent (e.g., in increasing order) are provided to each of the samples. Then, the chromaticity of each of the samples is determined and compared by, for example, a spectrophotometer or a calibrated digital camera, as described above. The chromaticity of each of the samples can even be determined by visual inspection. The sample having a chromaticity that matches or is closest to the specific chromaticity within the matching tolerance is selected. In the same manner as before, the amount of the darkening agent to be added to the first thermoplastic composition is obtained by simple cross - multiplication. It should be noted that in the embodiment of selecting the closest sample, the number of samples (and thus the chromaticities) should be quite high such that the selected chromaticity is very close to the specific chromaticity. For example, fifty samples with different amounts of the darkening agent can be prepared in order to obtain fifty gray chromaticities for comparison.

[0060] In Figure 3 and Figure 4 Examples of a floor or wall covering 10 according to an embodiment of the present invention are depicted. From bottom to top, the floor or wall covering 10 includes: a support layer 12, a digitally printable layer 14, a decoration 16, a wear - resistant layer 18, and a PU top layer 20. The support layer 12 and the digitally printable layer 14 form a co - extruded substrate sheet 22. During the installation of the floor or wall covering 10, the bottom surface 24 of the support layer 12 is applied to the floor or wall.

[0061] Figure 4 The embodiment depicted in Figure 3 differs from the embodiment depicted in

[0062] in that the decoration is patterned (see, for example, the area 26 not touched by the decoration). It should be noted that the area 26 can be filled with the wear - resistant layer, for example, in the case where the composition for forming the wear - resistant layer is applied in a liquid state on the decoration, thereby filling the gap defined by the area 26.

[0063] Material Quantity (wt%) Virgin PVC 19-23 Recycled PVC 19-23 Stabilizer 1-2.5 Impact modifier 1-2.5 Processing aid 0.5-2 Filler 45-70 PE wax 0-0.5 Filler compatibilizer 0.5-2 Stearic acid 0.1-0.2 Darkening agent 0.01-0.1

[0064] Total: 100%

[0065] Table 1

[0066] The following Table 2 provides possible thermoplastic compositions for the digitally printable layer.

[0067] Material Quantity (wt%) Virgin PVC 22-30 Stabilizer 1-3 Impact modifier 1-2.5 Processing aid 0.5-2 Filler 45-60 PE wax 0-0.5 Filler compatibilizer 0.5-2 Stearic acid 0.01-0.10 Whitening agent 1-5

[0068] Total: 100%

[0069] Table 2

[0070] The weight percentages in Table 1 are given with respect to the entire thermoplastic composition (for the support layer or the digitally printable layer). The virgin PVC is VYNOVA S6760 (Vynova). The stabilizer is Mark CZ 2081 (Galata). The impact modifier is Durastrength 200 from Arkema. The processing aid is LG PA912 from LG. The filler is OMYA BL20 from OMYA. The PE wax is LUWAX A from BASF. The filler compatibilizer is Viscowax 443 from Innospec. The stearic acid is stearin RG from Brenntag. The whitening agent is Bieltytanowa RFC 5 (pigment) from Tytanpol. The darkening agent is carbon black corax from Orion.

[0071] Although specific embodiments have been described in detail herein, those skilled in the art will understand that various different modifications and substitutions to those details can be developed in accordance with the general teachings of this disclosure. Accordingly, the specific arrangements disclosed are intended to be illustrative only and do not limit the scope of the invention, which will be given in the full breadth of the appended claims and any and all equivalents thereof.

Claims

1. A method for producing a substrate sheet for decorative floor or wall covering, comprising: Providing a first thermoplastic composition comprising recycled PVC particles, the first thermoplastic composition having a chromaticity; Blending a colorant into the first thermoplastic composition to obtain a first thermoplastic composition having a specific chromaticity, the specific chromaticity being a predetermined specific target chromaticity; Providing a second thermoplastic composition; Co-extruding the first thermoplastic composition having the specific chromaticity with the second thermoplastic composition to form adjacent first and second co-extruded layers; Wherein the first co-extruded layer is a support layer having the specific chromaticity, the first co-extruded layer comprising the first thermoplastic composition; Wherein the second co-extruded layer is a digitally printable layer, the second co-extruded layer comprising the second thermoplastic composition, the digitally printable layer having a chromaticity brighter than that of the first thermoplastic composition; and Wherein the step of blending the colorant into the first thermoplastic composition is implemented as a negative feedback loop such that the chromaticity of the first thermoplastic composition increasingly approaches the specific chromaticity after each iteration until the chromaticity of the first thermoplastic composition matches the specific chromaticity within a matching tolerance.

2. The method according to claim 1, wherein, The step of blending the colorant comprises: a) Adding a colorant to the first thermoplastic composition to obtain a first thermoplastic composition having a deeper chromaticity; b) Comparing the deeper chromaticity with the specific chromaticity; and c) Based on the comparison, repeating steps a) and b) if necessary until a first thermoplastic composition having the specific chromaticity is obtained.

3. The method according to claim 1, wherein, The first thermoplastic composition comprises from 10 wt% to 50 wt% of recycled PVC particles.

4. The method according to claim 1, wherein The first thermoplastic composition comprises from 30 wt% to 70 wt% of one or more fillers.

5. The method according to claim 1, wherein The first thermoplastic composition comprises from 0.01 wt% to 0.1 wt% of a colorant.

6. The method according to claim 1, wherein, The second co-extruded layer has a thickness included in the range from 0.1 mm to 5 mm.

7. The method according to claim 1, wherein, The first co-extruded layer has a thickness included in the range from 2 mm to 15 mm.

8. A method for producing a decorative floor or wall covering, comprising: Providing a substrate sheet according to any one of claims 1 to 7; And Digitally printing a decoration on the digitally printable layer.

9. The method according to claim 8, comprising applying a wear-resistant layer on the digitally printed decoration.

10. The method according to any one of claims 8 to 9, comprising applying a polyurethane-based top layer.

11. The method according to claim 8, wherein, The decoration has a thickness included in the range from 0.05 mm to 1 mm.

12. The method according to claim 8, wherein The decoration is translucent.

13. A decorative floor or wall covering obtained by the method according to any one of claims 8 to 12.

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