Decorative panel, core layer and method for producing said panel

Abstract

The invention relates to a decorative panel, in particular a decorative floor panel, a decorative ceiling panel or a decorative wall panel, comprising: at least one core layer; a decorative top structure secured directly or indirectly to a top surface of the core layer. The invention also relates to a core layer for use in a decorative panel according to the invention. The invention also relates to a method for producing a decorative panel, in particular a decorative panel according to the invention.

Description

Technical Field

[0001] This invention relates to a decorative panel, particularly a decorative floor panel, decorative ceiling panel, or decorative wall panel, comprising: at least one core layer; and a decorative top structure directly or indirectly fixed to the top surface of said core layer. The invention also relates to a core layer for use in a decorative panel according to the invention. Furthermore, the invention relates to a method for producing decorative panels, particularly decorative panels according to the invention. Background Technology

[0002] Over the past few decades, numerous improvements have been observed in the field of decorative paneling, such as floor paneling and wall paneling. These improvements cover various aspects of decorative paneling, such as improved aesthetic appearance, improved mechanical connection profiles, improved acoustic performance, improved scratch resistance, and improved core composition. Regarding the latter, a trend can be observed where traditional core materials such as medium-density fiberboard (MDF) and high-density fiberboard (HDF) have been partially replaced by compositions based on other materials, such as polyvinyl chloride (PVC). Unlike MDF and HDF, PVC is waterproof, thus easy to maintain, and exhibits relatively attractive noise reduction properties. However, the use of PVC in the core composition of decorative paneling is not without controversy. Health risks may arise because PVC is typically softened using hazardous plasticizers such as phthalates. Furthermore, toxic chemicals are used in the production of PVC, generating toxic byproducts and waste. Furthermore, in the event of a fire, PVC-based panels may release carcinogens called dioxins and furans, which are undesirable from a health, safety, and environmental perspective. In addition, PVC has a significant carbon footprint (also known as occult carbon), which puts pressure on its use in the core layer of decorative panels. As awareness of material health, safety, and the environment increases, the industry and its customers are demanding the use of alternative raw materials in the manufacture of decorative panels. More specifically, there is a need to develop a core composition for decorative panels that is relatively healthy and safe, and significantly reduces the carbon footprint to protect the environment as much as possible. Summary of the Invention

[0003] Therefore, the first objective of this invention is to provide a decorative panel with a relatively low carbon footprint.

[0004] Therefore, a second object of the present invention is to provide a decorative panel having an improved core composition.

[0005] Therefore, a third object of the present invention is to provide a decorative panel having a healthier, safer, and / or more environmentally friendly core composition.

[0006] Therefore, a fourth object of the present invention is to provide a PVC-free decorative panel.

[0007] At least one of these objectives can be achieved by providing a decorative panel according to the preamble, the decorative panel comprising:

[0008] At least one core layer;

[0009] A decorative top structure that is directly or indirectly fixed to the top surface of the core layer;

[0010] The at least one core layer comprises at least one chain-extended condensate, preferably at least one chain-extended polyester, more preferably at least one chain-extended polyethylene terephthalate (PET) and / or at least one chain-extended polyethylene terephthalate (PETG). The chain-extended polyester preferably consists at least partially of condensate-based molecules, more preferably polyester-based molecules, which may be PET-based molecules and / or PETG-based molecules, wherein each condensate-based molecule comprises at least two polymer chains composed of the condensate, preferably polyester, more preferably PET or PETG or a combination of PET and PETG, the polymer chains being chemically bonded to each other by at least one chain extender.

[0011] The decorative panel according to the invention has several advantages. First, since the core layer material composition is based on condensation polymers, preferably polyesters, more preferably PET and / or PETG, the carbon footprint of the core composition, and therefore the carbon footprint of the decorative panel itself, can be reduced, particularly compared to PVC. Furthermore, these polymers are relatively healthier and safer than PVC because they do not require hazardous plasticizers such as phthalates to allow for greater flexibility in their application. Moreover, the production of condensation polymers such as polyesters, preferably PET and / or PETG (as opposed to PVC) does not result in toxic byproducts, and these condensation polymers (as opposed to PVC) do not release highly carcinogenic substances, namely dioxins and furans, in the event of a fire. Therefore, (recycled) condensation polymers (preferably polyesters, more preferably PET and / or PETG) have significant advantages over PVC, and the use of said material further reduces the implicit carbon (carbon footprint) of the core composition, and thus the implicit carbon (carbon footprint) of the decorative panel itself. It is likely preferable that the core layer is free of polyvinyl chloride (PVC) to keep the carbon footprint of the core composition limited.

[0012] PETG (diol-modified polyethylene terephthalate) is a thermoplastic polymer belonging to the polyester family. It is a modification of PET (polyethylene terephthalate) by adding diols during the polymerization process. This modification alters the material's properties, imparting characteristics such as improved transparency, impact resistance, and processability. Compared to other conventional plastics (such as PVC), PETG's relatively high impact resistance makes the core layer less prone to cracking or breakage. This property makes it suitable for applications requiring durability and toughness. Furthermore, PETG is easily processed by methods such as extrusion due to its wide processing window. Both PET and PETG are polymers composed of repeating units of ethylene terephthalate. The difference lies in the addition of diols to PETG during polymerization. As mentioned above, this diol modification alters the material's properties. Generally, PETG is more impact-resistant and easier to process than PET, but it typically has slightly lower heat resistance compared to PET. The toughness of PETG and / or PET is further improved by preferably using at least one chain extender (binding molecule) to bond at least a portion of the PETG polymer chains and / or at least a portion of the PET polymer chains together. It is conceivable that the core layer contains only PETG (or only PET, not PETG). It is conceivable that the core layer contains both PET and PETG. In the latter case, it is conceivable that the PET chains can be (chemically) bonded to the PETG chains, or that the PET chains are (chemically) bonded to the PETG chains, preferably by using a chain extender.

[0013] Compared to PVC, PETG and PET have the advantages of greater rigidity and better thermal stability. When decorative panels are exposed to sunlight, the panel temperature can easily exceed 50 degrees Celsius, which typically causes deformation of PVC-based panels, while the more heat-resistant panels according to the invention prevent this deformation. Furthermore, the panels according to the invention are also relatively waterproof and moisture-proof (unlike MDF and HDF), resulting in additional major advantages of the decorative panels according to the invention compared to conventional panels.

[0014] During thermomechanical processing, PETG and / or PET are subjected to high temperatures and shear stress conditions, which can severely degrade PETG and / or PET in terms of molar mass and (interrelated) viscosity. Primitive PET and / or primitive PETG typically have a molar mass between 20,000 g / mol and 30,000 g / mol, while recycled PET typically has a molar mass between 10,000 g / mol and 20,000 g / mol. Water (and / or PVC, present in trace amounts) in recycled PET materials causes PET (and / or PETG) chain breakage during normal extrusion. At processing temperatures (270–290°C), hydrolysis occurs between water and PET (and / or PETG), producing shorter chains with carboxyl and hydroxyl end groups. Thermal cleavage of PET (and / or PETG) ester bonds results in PET (and / or PETG) chains with carboxyl and vinyl ester end groups. Broken PET chains (PET with reduced molar mass) are less desirable for decorative paneling. To increase the molar mass and / or viscosity of PET (and / or PETG) to a higher level for use in decorative panels, broken PET chains are chemically bonded (reconnected) using one or more chain extenders, preferably by reactive extrusion. These chain extenders are preferably bifunctional or multifunctional because they have high reaction rates without producing (undesirable) byproducts (possibly other than water). In this way, PET (and / or PETG) with a higher (average) molar mass and therefore a higher viscosity, preferably at least 0.8 dl / g, can be produced to allow or improve the manufacture of the core layer, and thus allow or improve the manufacture of the decorative panel itself. Prior to chain extension, the recycled PET (and / or recycled PETG) used as the raw material constituting the core composition preferably has a viscosity of 0.5 dl / g to 0.6 dl / g. This viscosity will increase to a value of at least 0.8 dl / g (and preferably less than 1.0 dl / g) during the chain extension process (typically during reactive extrusion). Preferably, the core layer and / or decorative panel are substantially free of PVC to reduce the carbon footprint of the decorative panel. It is conceivable, but not mandatory, that the core layer and / or decorative panel are substantially free of virgin PET (and / or virgin PETG) to reduce the carbon footprint of the decorative panel. This viscosity is preferably measured by applying Chinese standard T / CCFA 00011-2021, which requires a test temperature of 25 degrees Celsius.

[0015] Preferably, at least a portion of the PETG and / or PET-based molecules comprises at least three or at least four polymer chains composed of PETG and / or PET, which are chemically bonded to each other by at least one chain extender. This can be achieved, for example, by applying a tetrafunctional chain extender such as pyromellitic dianhydride (PMDA). In the latter example, the PMDA chain extender forms a molecular center to which the (outer ends) of the four chains of the preferably recycled PETG and / or PET are chemically bonded. It is also conceivable that at least a portion of the PETG and / or PET-based molecules comprises more than four polymer chains composed of PETG and / or PET chemically bonded to each other by at least one chain extender. This can be achieved, for example, by using a combination of different chain extenders. By increasing the number of reconnected PETG and / or PET chains, the molar mass of the chain-extended PETG and / or chain-extended PET can be increased, and thus its viscosity can be increased to obtain the desired properties for manufacture (and / or use).

[0016] Preferably, at least a portion of the PETG and / or PET-based molecules comprises recycled PETG and / or recycled PET, respectively. Preferably, the at least one core layer comprises at least one chain-extended polycondensate, preferably at least one chain-extended polyester, more preferably at least one chain-extended polyethylene terephthalate (PET) and / or at least one chain-extended polyethylene terephthalate (PETG) (and / or combinations thereof), wherein the chain-extended polycondensate is at least partially composed of molecules based on reclaimed polycondensate, preferably based on recycled polyester, more preferably based on recycled PET and / or recycled PETG, each molecule comprising at least two polymer chains composed of reclaimed polycondensate, preferably recycled polyester, more preferably recycled PET, recycled PETG, or combinations thereof, the polymer chains being chemically bonded to each other by at least one chain extender. This embodiment has several advantages. First, because the core layer's material composition is based on reclaimed shrinkage polymers, preferably recycled polyesters, and more preferably recycled PET and / or recycled PETG, the carbon footprint of the core composition, and therefore the carbon footprint of the decorative panel itself, can be further reduced, particularly compared to virgin fossil-based polymers (which are based on non-renewable fossil fuels). Furthermore, these recycled polymers are relatively healthier and safer than PVC because they do not require hazardous plasticizers such as phthalates to make the polymer more flexible for targeted applications. Therefore, reclaimed shrinkage polymers, preferably recycled polyesters, more preferably recycled PET and / or recycled PETG, have significant advantages over PVC, and the use of said recycled materials further reduces the implicit carbon (carbon footprint) of the core composition, and thus further reduces the implicit carbon (carbon footprint) of the decorative panel itself. To keep the carbon footprint of the core composition and therefore the carbon footprint of the decorative panel as limited as possible, it may be preferable that the core layer does not contain virgin fossil-based polymers. It may also be preferable that the core layer does not contain polyvinyl chloride (PVC).

[0017] It is conceivable that at least one chain extender is configured to chemically bond and / or actually chemically bond at least one (original and / or recycled) PET chain and / or at least one (original and / or recycled) PETG chain. It is conceivable that at least one chain extender is configured to chemically bond and / or actually chemically bond (i) at least one (original and / or recycled) PET chain and / or at least one (original and / or recycled) PETG chain, and (ii) at least one other (original and / or recycled) polymer chain. Therefore, various combinations of polymer chain bonding are conceivable.

[0018] It is conceivable, but not mandatory, that the core layer and / or decorative panel are substantially free of virgin PETG and / or virgin PET to reduce the carbon footprint of the decorative panel. However, it is also conceivable that, preferably, in addition to recycled PETG and / or recycled PET, the material composition of at least one core layer also includes virgin PETG and / or virgin PET. Since such virgin PETG and virgin PET have the same functional end groups as recycled PETG and recycled PET, recycled PETG and recycled PET may also and are likely to be part of molecules based on chain-extended PETG and / or chain-extended PET. Therefore, it is conceivable that the core layer comprises chain-extended PETG and / or chain-extended PET, at least partially composed of PETG-based molecules and / or PET-based molecules, wherein each molecule comprises at least one polymer chain composed of recycled PETG and / or recycled PET and at least one polymer chain composed of virgin PETG and / or virgin PET, chemically bonded to each other by at least one chain extender. In order to efficiently process mixtures of virgin PETG and recycled PETG and / or mixtures of virgin PET and recycled PET, particularly by using an extruder, it is preferable to select or choose two raw materials such that their melting points are substantially the same or close to each other. Preferably, the difference in melting points between the selected virgin PETG and the selected recycled PETG and / or between the selected virgin PET and the selected recycled PET is less than 10 degrees Celsius, more preferably less than 5 degrees Celsius, and even more preferably less than 3 degrees Celsius.

[0019] Typically, the length and therefore molar mass of recycled PETG chains and / or recycled PET chains are (significantly) smaller than those of virgin PETG chains and / or virgin PET chains. The molar mass of recycled PET and / or recycled PETG is preferably at least 10,000 g / mol and typically less than 20,000 g / mol, while the molar mass of virgin PET (and / or virgin PETG) is typically between 20,000 g / mol and 30,000 g / mol. Depending on the number of (re)linked PET chains in the chain-extended PET (and / or chain-extended PETG) molecules, the molar mass of these modified chain-extended PET molecules is preferably greater than 20,000 g / mol, and may even exceed 30,000 g / mol, 40,000 g / mol, and / or 50,000 g / mol, but is preferably less than 100,000 g / mol to ensure sufficiently low viscosity, thereby allowing for proper extrusion of the chain-extended PET (and / or chain-extended PETG) material. The (re)linking of PETG chains and / or PET chains typically occurs within the extruder and is considered to be a chemical reaction between the PETG chains and / or PET chains and at least one chain extender. Optionally, water molecules are generated during this reaction. Depending on the properties of the (recycled) PETG and / or (recycled) PET used as feedstock, particularly the average chain length, the type and amount of chain extender can be selected to achieve a preferred molar mass, thereby achieving a viscosity suitable for the appropriate processing of materials based on modified chain-extended PETG and / or chain-extended PET.

[0020] It is conceivable that not all raw materials initially present in the masterbatch to be extruded will react during reactive extrusion. Therefore, it is conceivable that the core layer comprises unbonded recycled PETG (if applied) and / or unbonded virgin PETG, and / or wherein the core layer contains unbonded chain extender molecules. Optionally, the core layer comprises unbonded recycled PET (if applied) and / or unbonded virgin PET, and / or wherein the core layer contains unbonded chain extender molecules.

[0021] As described above, it is conceivable, and even preferred, that the core layer comprises at least partially extended PETG and / or extended PET molecules based on polyethylene terephthalate (PETG) and / or polyethylene terephthalate (PET), wherein each molecule comprises at least two polymer chains composed of PETG and / or PET chemically bonded together by at least two different chain extenders. Optionally, each PETG and / or PET molecule comprises at least two polymer chains composed of recycled PETG and / or recycled PET chemically bonded together by at least two different chain extenders. This can increase the number of chemically bonded PETG and / or PET chains in a single molecule, thereby increasing the molar mass and viscosity of the core layer composition during extrusion.

[0022] At least one chain extender may be or may comprise at least one multifunctional epoxide oligomer. Prior to bonding with the PETG chain and / or PET chain, the multifunctional epoxide oligomer may be represented by the following chemical structure:

[0023] in:

[0024] R1 to R5 are H, CH3, higher alkyl groups or combinations thereof;

[0025] R6 is an alkyl group; and

[0026] x, y, and z are each between 1 and 20.

[0027] This type of solid multifunctional epoxide oligomer is also known as ADR-4368 (from BASF), abbreviated as "ADR".

[0028] ADRs possess at least four functional groups, enabling rapid bonding of at least four PETG chains and / or PET chains. The following describes the (rapid) mutual chemical bonding of at least four PET chains via ADRs:

[0029] Additionally or alternatively, prior to bonding with the PETG chain and / or the PET chain, at least one chain extender may be or may contain at least one dianhydride, preferably pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA). PMDA (1H,3H-benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetraone) is represented by the following chemical structure:

[0030] MEDA (1,2:3,4-benzenetetracarboxylic anhydride) can be represented by the following chemical structure:

[0031] Both dianhydrides are tetrafunctional and each can chemically bond four PETG chains and / or PET chains. Typically, this bonding process constitutes a two-stage reaction mechanism, in which two PETG chains and / or PET chains are chemically bonded to the dianhydride, such as PMDA, in the first rapid reaction step. The first rapid reaction step, in which two PET chains are chemically bonded to the dianhydride, particularly PMDA, is illustrated below:

[0032] In the second, slower reaction step, two additional PETG chains and / or PET chains are chemically bonded to or capable of chemically bonding to the dianhydride. The second, slower reaction step, in which two additional PET chains are chemically bonded to the dianhydride, is illustrated below:

[0033] In this second reaction step, water molecules are produced. This results in chain-extended PMDA-PETG molecules and / or chain-extended PDM-PET molecules with four PETG arms and / or PET arms.

[0034] It is conceivable, and perhaps even preferred, that the core layer comprises: (i) at least one (bonded) dianhydride, preferably (bonded) pyromellitic dianhydride (PMDA) and / or (bonded) trimellitic dianhydride (MEDA) and (ii) (bonded) A mixture of ADR 4368 (from BASF; see above). Preferably, the dianhydride is mixed with... The mass ratio of ADR 4368 is between 1:1 and 2:1; more preferably, this mass ratio is 6:4. The molar mass of ADR is approximately 6800 g / mol, and the molar mass of PMDA is 218.12 g / mol. By applying this balanced ratio, the molar mass of the chain-extended PETG molecules and / or chain-extended PET molecules is high enough to achieve the desired viscosity for extrusion purposes, while being low enough or limited enough to prevent the viscosity from becoming too high to extrude. By applying this chain extender mixture, more comprehensive molecules (molecular complexes) can be achieved, such as... Figure 8 As shown, each molecule may have at least eight PETG chains and / or PET chains. In this reaction, each PMDA molecule reacts with four PETG chains and / or PET chains (as described above), and then each four-armed PMDA-PETG and / or PMDA-PET molecule chemically bonds with ADR to produce ADR-(PMDA-PETG). n And / or ADR-(PMDA-PET) n Molecules, where n≥2, such as Figure 8 As shown. Other variations are also conceivable. ADR-(PMDA-PETG) n And / or ADR-(PMDA-PET) n The presence of molecules can occur in conjunction with the presence of ADR-PETG and / or ADR-PET molecules and / or the presence of PMDA-PETG and / or PMDA-PET molecules as described above. Therefore, in more general terms, it is conceivable that at least a portion of the PETG and / or PET-based molecules each contain:

[0035] Multiple clusters, wherein each cluster comprises multiple polymer chains composed of PETG and / or PET and / or recycled PETG and / or recycled PET, chemically bonded together by dianhydrides, preferably by PMDA and / or MEDA;

[0036] The clusters are chemically bonded to each other through the multifunctional epoxide oligomers.

[0037] Additionally or alternatively, at least one chain extender comprises pentaerythritol diphosphite (available from Ciba Specialty Chemicals) 126) or formed therefrom. In addition to one or more primary chain extenders, such as one or more of the chain extenders described above, the chain extender may also be used as a secondary chain extender. 126 can be represented by the following chemical formula:

[0038] During the chain extension reaction with PETG and / or PET, 126 molecules will be cut into two 126 fragments, each capable of chemically bonding to three PETG chains and / or PET chains (PETG molecules and / or PET molecules). Here, the molar mass of the chain-extended PETG molecules and / or chain-extended PET molecules also increases with the concentration of the chain extender, while the crystallinity tends to be lower.

[0039] The use of one or more additional or alternative chain extenders is also conceivable. For example, the chain extender could be an epoxy chain extender containing at least one epoxide group, such as 2-methyl-ethylene oxide methyl ester. Such epoxy chain extenders are generally suitable for ring-opening polymerization reactions with (recycled) PETG chains and / or (recycled) PET chains.

[0040] The amount of chain-extended polyethylene terephthalate (PET) and / or chain-extended PETG in the core layer is preferably between 25% and 45% of the core layer weight, more preferably between 30% and 35%. The amount of chain extender in the core layer is preferably between 0.25% and 4% of the core layer weight, more preferably between 0.5% and 1%. The remainder of the core layer is typically formed of one or more fillers and / or one or more functional additives, as described below.

[0041] In an embodiment of the decorative panel according to the invention, the decorative panel comprises a plurality of panel layers, such as a core layer, at least one abrasion-resistant layer, and / or at least one intermediate layer located between the core layer and the at least one abrasion-resistant layer, wherein at least one panel layer comprises recycled PETG and / or virgin PETG, and optionally, at least one other panel layer comprises recycled PET and / or virgin PET. The PETG and / or PET may be chain-extended polymers, unmodified polymers (i.e., non-chain-extended polymers), or combinations thereof.

[0042] In embodiments of the decorative panel according to the invention, the panel comprises a plurality of laminated core layers, wherein at least one core layer, and preferably at least two core layers, or even each core layer comprises PETG and / or PET, preferably recycled PETG and / or recycled PET, more preferably chain-extended (recycled) PETG and / or chain-extended (recycled) PET. At least one of the core layers may be a reinforcing layer, such as a glass fiber layer. The core layers comprising (recycled) PETG and / or (recycled) PET may have different compositions or may have the same composition. The core layers may be manufactured by co-extrusion, particularly reactive co-extrusion, wherein, preferably, during the (co)extrusion process, the (recycled) PETG chains and / or (recycled) PET chains are extended by using one or more chain extenders.

[0043] In a preferred embodiment, the panel comprises at least three laminated core layers in an alternating configuration, wherein core layers having substantially the same composition surround core layers with different compositions. This alternating configuration can be, for example, an ABA configuration, where the outer layer (A) has substantially the same composition, while the inner layer (B) has a different composition. The outer layer (A) preferably has a lower viscosity than the inner layer (B). This has a dual advantage. The first advantage is that the lower viscosity results in a relatively smooth surface of the outer layer (A), which facilitates the easy application of decorative top structures, including, for example, digitally printed decorative layers, on top. Preferably, at least one of these outer layers (A) is solid (unfoamed). The second advantage of providing a higher viscosity for the inner layer (B) is that it allows for the application of more filler, such as limestone, in said layer (B), which reduces the cost of the inner layer (B). Furthermore, the inner layer (B) can be a foamed layer, which reduces density and generally improves the sound damping characteristics and / or comfort of the decorative panel itself. Therefore, at least one core layer can be unfoamed, and / or at least one core layer can be foamed. The thickness of each outer core layer (A) can be less than the thickness of the inner core layer (B), and it is also possible for the total thickness of the outer core layers (A) (together) to be less than the thickness of the inner core layer (B). Alternative configurations are also conceivable.

[0044] It is conceivable that only a single core layer is applied, which can be foamed or unfoamed. It is conceivable that at least one core layer, such as an inner core layer (B), contains PETG, while another core layer, such as at least one outer core layer (A), contains PET and / or another core layer contains recycled PET and / or recycled PETG. This AB and / or ABA and / or (AB) n (Where n>1) Configurations can be achieved through co-extrusion, particularly due to the structural similarities between PET and PETG. It has been found that PETG is more suitable than PET as a support layer and / or for adhesion to decorative top structures and / or UV-cured layers applied to the PETG layer. Due to the improved adhesive properties of PETG, it may no longer be necessary to apply a separate adhesive layer above the PETG layer to achieve a reliable and durable bond between the core layer and the decorative structure. The type of filler (e.g., calcium carbonate) can be the same for each core layer, or alternatively, it can differ between at least two core layers.

[0045] Decorative panels may comprise multiple panel layers, such as a core layer, at least one abrasion-resistant layer, and / or at least one intermediate layer between the core layer and the at least one abrasion-resistant layer, wherein at least one panel layer, and preferably the core layer, comprises a foamed PETG layer and / or a foamed PET layer. Preferably, the foamed PETG layer and / or the foamed PET layer comprises at least one blowing agent, such as an azodicarbonamide (AC) blowing agent, and / or at least one foaming modifier, such as an acrylate (ACR) foaming modifier. To achieve the foamed PETG (and / or foamed PET) layer, it is advantageous that the layer comprises at least one blowing agent, such as an azodicarbonamide (AC) blowing agent, and / or at least one foaming modifier, such as an acrylate (ACR) foaming modifier. For example, such a foamed layer can be prepared from raw materials comprising, by weight, the following components: 100 parts PET and / or PETG, 1 to 2 parts foaming agent (e.g., AC foaming agent), and / or 14 to 16 parts foaming regulator (e.g., ACR foaming regulator). Optionally, at least 100 parts (e.g., 150 to 350 parts, particularly 300 parts) of inorganic filler, such as limestone and / or talc, can be added to the raw material composition. Optionally, a wax (e.g., polyethylene wax) can be added to the raw material composition in a relative amount of, for example, 1 to 3 parts. Optionally, the raw material composition can contain at least one mold release agent, for example, 3 to 7 parts, particularly 5 parts. Optionally, at least one reinforcing agent can be added to the raw material composition, for example, in an amount of 5 to 15 parts, particularly 10 parts.

[0046] Preferably, the average molar mass of the interbonded (recycled) PETG chains and / or (recycled) PET chains constituting part of the chain-extended PETG molecules and / or chain-extended PET molecules, and therefore the original (recycled) PETG and / or original (recycled) PET materials used to form the chain-extended PETG molecules and / or chain-extended PET molecules, is less than 20,000 g / mol, preferably less than 15,000 g / mol, more preferably less than 12,000 g / mol. Preferably, this average molar mass is greater than 10,000 g / mol to ensure sufficiently high viscosity, and preferably at least 0.5 dl / g. Depending on the number of PETG chains and / or PET chains bonded by at least one chain extender used (and depending on the molar mass of the chain extender used), the molar mass of the chain-extended PETG and / or chain-extended PET molecules is approximately a multiple of these preferred values.

[0047] The core layer preferably comprises at least one inorganic filler (e.g., limestone) and / or an organic filler (e.g., wood particles). Typically, extended-chain PETG molecules and / or extended-chain PET molecules form a polymer matrix in which one or more additives are dispersed. Other possible inert and / or functional fillers include, for example: chalk, calcined clay, glass particles, glass fibers, carbon particles, silicon particles, (another) mineral filler, rice, (another) natural filler, (another) (auxiliary) polymer, such as elastomers and / or latex. These fillers are generally used to reduce the cost of the core layer and / or to make the core layer more flexible or more rigid (hard). The amount of filler in the core layer is preferably at least 50% of the weight of the core layer, more preferably 60% to 70% of the weight of the core layer. Preferably, the weight of the filler in the core layer is at least 1.5 times the weight of the PETG and / or PET of the core layer, preferably at least 1.5 times the weight of the extended-chain PETG and / or extended-chain PET. The presence of a relatively large proportion (≥ weight percentage) of filler in the core layer results in relatively large distances between the (recycled) PETG and / or PET molecules initially present in the masterbatch (fed to the extruder for extrusion). To improve the chain extension process during reactive extrusion, it is preferable to add an excess of a chain extender, such as PMDA, to the masterbatch. This will increase the reactivity, thereby increasing the yield of the chain extension process during masterbatch processing.

[0048] Preferably, the core layer comprises at least one lubricant configured to withstand temperatures of at least 200 degrees Celsius, preferably at least 255 degrees Celsius (which roughly corresponds to the melt temperature of (recycled) PETG and / or (recycled) PET), and more preferably at least 280 degrees Celsius (which roughly corresponds to the extrusion temperature). The lubricant is preferably present in an amount less than 1% of the core layer weight. Extrusion typically occurs at these higher temperatures (>200 degrees Celsius). The primary function of the lubricant is to reduce friction, minimize wear, and prevent overheating of the part during extrusion. Preferably, the core layer comprises at least one lubricant formed from silicone oil, and preferably, the amount of this lubricant is less than 1% of the core layer weight. Silicone oil is an example of a lubricant capable of withstanding extrusion temperatures of at least 200 degrees Celsius, as opposed to, for example, ordinary waxes.

[0049] The core layer preferably contains at least one toughening agent, the amount of which is preferably less than 10% of the core layer weight, more preferably 3% to 8% of the core layer weight. This toughening agent can be formed, for example, from a maleic anhydride-functionalized styrene-ethylene-butene-styrene terpolymer (SEBS-g-MA) (e.g., FG1901X obtained from KRATON Corporation). This toughening agent can reduce the melt flow index (MFI) of the (recycled) PETG and / or (recycled) PET-based masterbatch to, for example, a value of about 50 g / 10 min during extrusion, which is beneficial for core layer production.

[0050] The decorative top structure preferably comprises a primer layer applied to the top surface of the core layer and at least one additional layer applied on top of the primer layer. The primer may, for example, contain calcium carbonate and / or hydrogenated castor oil, and preferably, the adhesive primer is a two-component adhesive, such as based on a (polyether) polyol and a curing agent. The primer layer facilitates the adhesion of another layer (e.g., a base coating) to the core layer.

[0051] The decorative top structure may include at least one base coating applied directly or indirectly to the top surface of the core layer, and at least one additional layer applied to the base coating. The base coating is typically configured to provide a substrate for applying the decorative layer. At least one base coating is preferably a white layer, which improves the color fidelity of the decorative layer optionally digitally printed over the base coating. The white base coating may be a UV-curable layer. The white base coating may, for example, contain unsaturated aliphatic polyurethane acrylate and / or hydroxyethyl methacrylate and / or titanium dioxide. The white base coating may be covered by another base coating to balance surface tension, thereby preventing shrinkage of ink droplets optionally printed on the base coating. The additional base coating may be a UV-curable layer. The additional base coating may, for example, contain unsaturated aliphatic polyurethane acrylate and / or hydroxyethyl methacrylate and / or calcium carbonate and / or silica.

[0052] Decorative top structures typically include at least one decorative layer applied directly or indirectly to the top surface of the core layer, and preferably include at least one additional layer applied to said decorative layer, such as an abrasion-resistant layer and / or a scratch-resistant layer. The decorative layer is preferably a digitally printed decorative layer, but may also be formed from a veneer layer (wood, stone, polymer, other synthetic, or natural layer), or from a decorative, preferably polymer-based film, such as a film containing PETG and / or PET, particularly a film containing (recycled) PET and / or a film containing (recycled) PETG. The abrasion-resistant and scratch-resistant layers (preferably used as a top coating) are preferably at least partially transparent and / or translucent UV-cured layers. Additionally or alternatively, at least one abrasion-resistant layer and / or at least one scratch-resistant layer contains PETG and / or PET, wherein the thickness of the PETG and / or PET can range from 10 μm to 100 μm. The abrasion-resistant and / or scratch-resistant layer containing PETG and / or PET can be a film containing PETG and / or PET. This membrane has excellent transparency, heat resistance, durability and chemical resistance.

[0053] The top surface of the decorative top structure is provided with an embossed pattern, also known as an embossed structure, wherein the embossed pattern is preferably aligned with a decorative image of the decorative layer. The embossed pattern may initially be set in one of the wear-resistant layers or another intermediate layer and may be covered by the top coating, such that the embossing of the pattern remains at least partially visible and / or tangible on the top surface of the decorative top structure.

[0054] It is conceivable that the decorative top structure comprises a single embossed abrasion layer, preferably containing PET and / or PETG, and / or formed from this abrasion layer, wherein the abrasion layer has a decorative print on its underside (facing the core layer). This decorative print can be simply a layer of decorative ink, or it can be a separate decorative film. The embossing applied to or on the abrasion layer is preferably aligned with the decorative print. In this way, a relatively compact, simple, and therefore efficient decorative panel construction can be achieved.

[0055] The panel may include a backing layer that is directly or indirectly attached (e.g., glued) to the bottom surface of the core layer, wherein the backing layer preferably consists of at least PET and / or PETG. The backing layer may be foamed or unfoamed. The backing layer may contribute to the sound damping properties and / or comfort of the decorative panel. The backing layer preferably contains PETG and / or PET, more preferably recycled PETG and / or recycled PET. It is conceivable that, like the core layer, the backing layer contains at least partially at least one chain-extended condensate polymer composed of at least one chain-extended polyester, more preferably at least one chain-extended PET, and / or at least one chain-extended PETG, wherein each molecule comprises at least two polymer chains composed of condensate polymer, preferably polyester, more preferably PET and / or PETG, said polymer chains being chemically bonded to each other by at least one chain extender. Optionally, at least a portion of the condensation polymer-based molecules, preferably polyester-based molecules, more preferably PET-based molecules, and / or PETG-based molecules, comprises at least two chains chemically bonded to each other by at least one chain extender, consisting of recycled condensation polymers, preferably recycled polyesters, more preferably recycled PETs, and / or recycled PETGs.

[0056] It is conceivable that the panel includes complementary connecting profiles at at least a pair of opposing side edges, thereby allowing the interconnection of adjacent decorative panels. This allows the decorative panels according to the invention to achieve, for example, so-called floating (unglued) floor coverings or wall coverings. Each side edge of the panel may be provided with a connecting profile. Each connecting profile may include one or more tongues and / or one or more grooves. The connecting profile may be formed substantially of a core material (by removing the core material at the side edges).

[0057] The panel can be rectangular. It can also be square, or have alternative polygonal shapes such as triangles, hexagons, and parallelograms. The thickness of the core layer can vary, but is typically between 4 mm and 10 mm, preferably between 4.5 mm and 8 mm.

[0058] The present invention also relates to a core layer for use in a decorative panel according to the invention, wherein the core layer comprises at least partially extended PET and / or extended PETG composed of molecules based on polyethylene terephthalate (PET) and / or polyethylene terephthalate (PETG), wherein each molecule comprises at least two polymer chains composed of PET and / or PETG chemically bonded to each other by at least one chain extender. Optionally, the extended PET and / or extended PETG comprises at least partially PET and / or PETG molecules, wherein each molecule comprises at least two polymer chains composed of recycled PET and / or recycled PETG chemically bonded to each other by at least one chain extender.

[0059] The present invention also relates to a method for producing decorative panels, particularly decorative panels according to the present invention, comprising the following steps:

[0060] a) Mixing PETG and / or PET material with at least one chain extender, wherein the PETG and / or PET material preferably has an intrinsic viscosity between 0.50 dl / g and 0.80 dl / g, more preferably between 0.50 dl / g and 0.60 dl / g, and / or has a molar mass between 10,000 g / mol and 20,000 g / mol;

[0061] b) The mixture is loaded into an extruder, preferably a twin-screw extruder;

[0062] c) The mixture is extruded through the extruder, preferably at a temperature between 250 and 300 degrees Celsius, more preferably at a temperature between 256 and 285 degrees Celsius, wherein at least a portion of the PETG and / or PET material reacts with at least a portion of the chain extender to produce chain-extended polyethylene terephthalate (PETG) and / or chain-extended polyethylene terephthalate (PET), wherein at least two polymer chains composed of PETG and / or PET are chemically bonded to each other by the chain extender, wherein water is optionally produced, and wherein a core layer of a decorative panel is produced;

[0063] d) Cool the extruded core layer, preferably actively, to a temperature below 100 degrees Celsius;

[0064] e) Apply a decorative top structure over the core layer to form a decorative panel.

[0065] Optionally, during step a), recycled PETG and / or recycled PET are mixed with at least one chain extender. Therefore, it is conceivable that during step c), at least a portion of the recycled PETG and / or recycled PET material reacts with at least a portion of the chain extender to produce chain-extended polyethylene terephthalate (PETG) and / or chain-extended polyethylene terephthalate (PET), wherein at least two polymer chains composed of recycled PETG and / or recycled PET are chemically bonded to each other through the chain extender.

[0066] During step a), at least one release agent can be added to the mixture of PETG material and at least one chain extender to form a lubricating film during step c). Because PETG melt readily adheres to metal, it tends to stick to the die surface during extrusion, hindering smooth flow and affecting the stable production of PETG-based panel layers. Furthermore, due to PETG adhesion, it may decompose under prolonged heating, resulting in a relatively rough surface of the extruded layer. For this reason, it is advantageous to add at least one release agent to the mixture (before extrusion). Such a release agent forms a stable lubricating film between the metal die surface and the PETG-containing melt during extrusion, eliminating the risk of adhesion between the die and the melt mixture. Preferably, the release agent contains ester groups, which ensure that the release agent is absorbed and fixed to the surface of the PETG chains. Furthermore, the addition of the release agent ensures the smooth production of foamed PETG-based layers. The release agent preferably contains a long-chain alkane backbone. The release agent is preferably heat-resistant to temperatures of at least 200°C.

[0067] Preferably, the mass ratio of PETG and / or PET to chain extender mixed during step a) is between 100:1 and 100:2 (50:1). Optionally, the mass ratio of recycled PETG and / or recycled PET to chain extender mixed during step a) is between 100:1 and 100:2 (50:1). This results in sufficient chain extender connecting sufficient (recycled) PETG chains and / or (recycled) PET chains. Preferably, during step a), at least two chain extenders are mixed, wherein the first chain extender is formed from at least one dianhydride, preferably pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA), and the second chain extender is formed from ADR, wherein the mass ratio of the first chain extender to the second chain extender is preferably between 1:1 and 2:1, more preferably 6:4. By preferably applying this chain extender mixture at the preferred mass ratio, desired and / or controlled molar masses of chain-extended PETG and / or PET can be obtained during the reactive extrusion process according to step c), and thus desired viscosities of chain-extended PETG and / or PET (preferably at least 0.8 dl / g) can be obtained. Further advantages and embodiments have been described above and will be described in a comprehensive manner below.

[0068] Further embodiments of the invention will be presented in the following set of non-limiting provisions.

[0069] Terms:

[0070] 1. A decorative panel (1), particularly a decorative floor panel, a decorative ceiling panel, or a decorative wall panel, comprising:

[0071] At least one core layer (2);

[0072] A decorative top structure (6) directly or indirectly fixed to the top surface of the core layer (2);

[0073] The at least one core layer (2) comprises at least partially extended polyethylene terephthalate (PET) and / or preferably extended polyethylene terephthalate (PETG) molecules, wherein each molecule comprises at least two polymer chains composed of PET and / or PETG, the polymer chains preferably being chemically bonded to each other by at least one chain extender.

[0074] 2. The decorative panel (1) according to Clause 1, wherein at least a portion of the PET and / or PETG-based molecules comprises at least four polymer chains composed of PET and / or PETG that are chemically bonded to each other by at least one chain extender.

[0075] 3. The decorative panel (1) according to Clause 2, wherein at least a portion of the PET and / or PETG-based molecules comprises more than four polymer chains composed of PET and / or PETG chemically bonded to each other by at least one chain extender.

[0076] 4. The decorative panel (1) according to any one of the preceding clauses, wherein the extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) are at least partially composed of PET and / or PETG-based molecules, wherein each molecule comprises at least two polymer chains composed of recycled PET and / or recycled PETG that are chemically bonded to each other by at least one chain extender.

[0077] 5. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises at least partially extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) composed of molecules based on PET and / or PETG, wherein each molecule comprises at least one polymer chain composed of recycled PET and / or recycled PETG and at least one polymer chain composed of virgin PET and / or virgin PETG, chemically bonded to each other by at least one chain extender.

[0078] 6. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises unbonded recycled PET and / or unbonded virgin PET.

[0079] 7. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises unbonded recycled PETG and / or unbonded virgin PETG.

[0080] 8. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises unbonded chain extender molecules.

[0081] 9. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises at least partially extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) composed of molecules based on PET and / or PETG, wherein each molecule comprises at least two polymer chains composed of PET and / or PETG chemically bonded to each other by at least two different chain extenders.

[0082] 10. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer (2) comprises at least partially extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) composed of molecules based on PET and / or PETG, wherein each molecule comprises at least two polymer chains composed of recycled PET and / or recycled PETG chemically bonded to each other by at least two different chain extenders.

[0083] 11. The decorative panel (1) according to any one of the preceding clauses, wherein at least one chain extender comprises a multifunctional epoxide oligomer.

[0084] 12. The decorative panel (1) according to Clause 11, wherein the multifunctional epoxide oligomer (ADR) is represented by the following chemical structure prior to bonding to the PET and / or PETG chains:

[0085] in:

[0086] R1 to R5 are H, CH3, higher alkyl groups or combinations thereof;

[0087] R6 is an alkyl group; and

[0088] x, y, and z are each between 1 and 20.

[0089] 13. The decorative panel (1) according to any one of the preceding clauses, wherein, prior to bonding with PET and / or PETG chains, at least one chain extender comprises at least one dianhydride, preferably pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA).

[0090] 14. The decorative panel (1) according to clauses 12 and 13, wherein the core layer comprises: (i) at least one dianhydride, preferably a mixture of pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA) and (ii) ADR, wherein preferably, the mass ratio of the dianhydride to the ADR is between 1:1 and 2:1; more preferably, the mass ratio is 6:4.

[0091] 15. The decorative panel (1) as described in Clause 12 or 13 and Clause 13 or 14, wherein at least a portion of the molecules based on PET and / or PETG each comprise:

[0092] Multiple clusters, wherein each cluster comprises multiple polymer chains composed of PET and / or PETG that are chemically bonded to each other via dianhydrides, preferably via PMDA and / or MEDA;

[0093] The clusters are chemically bonded to each other through the multifunctional epoxide oligomers.

[0094] 16. The decorative panel (1) as described in Clause 12 or 13 and Clause 13 or 14, wherein at least a portion of the molecules based on PET and / or PETG each comprise:

[0095] Multiple clusters, each containing multiple polymer chains composed of recycled PET and / or recycled PETG, chemically bonded together by dianhydrides, preferably by PMDA and / or MEDA;

[0096] The clusters are chemically bonded to each other through the multifunctional epoxide oligomers.

[0097] 17. The decorative panel (1) according to any one of the preceding clauses, wherein the amount of extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) in the core layer is between 25% and 45% of the weight of the core layer, preferably between 30% and 35%.

[0098] 18. The decorative panel (1) according to any one of the preceding clauses, wherein the amount of chain extender in the core layer is between 0.25% and 4% of the weight of the core layer, preferably between 0.5% and 1%.

[0099] 19. The decorative panel (1) according to any one of the preceding clauses, wherein the panel comprises a plurality of laminated core layers, wherein at least one core layer and preferably each core layer comprises PET and / or PETG, more preferably extended chain PET and / or extended chain PETG.

[0100] 20. The decorative panel (1) according to Clause 19, wherein the panel comprises three laminated core layers in an ABA configuration, wherein the outer layer (A) has the same composition and the inner layer (B) has different compositions.

[0101] 21. The decorative panel (1) according to any one of the preceding clauses, wherein at least one core layer is unfoamed and at least one core layer is foamed.

[0102] 22. The decorative panel (1) according to any one of the preceding clauses, wherein the average molar mass of each of the mutually bonded recycled PET chains and / or recycled PETG chains is less than 20,000 g / mol, preferably less than 15,000 g / mol, more preferably less than 12,000 g / mol.

[0103] 23. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least one inorganic filler, such as limestone, and / or an organic filler, such as wood particles.

[0104] 24. The decorative panel (1) according to clause 23, wherein the amount of filler in the core layer is at least 50% of the weight of the core layer, preferably 60% to 70% of the weight of the core layer.

[0105] 25. The decorative panel (1) according to clause 23 or 24, wherein the amount of filler in the core layer is at least 1.5 times the amount of PET and / or PETG, preferably extended chain PET and / or extended chain PETG, in the core layer.

[0106] 26. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least one lubricant configured to withstand a temperature of at least 200 degrees Celsius, and the lubricant is preferably present in an amount less than 1% of the weight of the core layer.

[0107] 27. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least one lubricant formed of silicone oil, and preferably, the amount of the lubricant is less than 1% of the weight of the core layer.

[0108] 28. The decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least one toughening agent, the amount of which is preferably less than 10% of the weight of the core layer, more preferably 3% to 8% of the weight of the core layer.

[0109] 29. The decorative panel (1) according to any one of the preceding clauses, wherein the decorative top structure comprises a primer layer applied to the top surface of the core layer and at least one additional layer applied to the primer layer.

[0110] 30. The decorative panel (1) according to any one of the preceding clauses, wherein the decorative top structure comprises at least one base coating applied directly or indirectly to the top surface of the core layer, and at least one additional layer applied to the base coating.

[0111] 31. The decorative panel (1) according to any one of the preceding clauses, wherein the decorative top structure includes at least one decorative layer applied directly or indirectly to the top surface of the core layer, and preferably includes at least one additional layer applied to the decorative layer, such as an abrasion-resistant layer and / or a scratch-resistant layer.

[0112] 32. The decorative panel (1) according to clause 31, wherein the decorative layer is a digitally printed decorative layer.

[0113] 33. The decorative panel (1) according to clause 31, wherein the decorative layer is formed of a finishing layer or a decorative film.

[0114] 34. The decorative panel (1) according to any one of clauses 31 to 33, wherein the top surface of the decorative top structure is provided with an embossed pattern, wherein the embossed pattern is preferably aligned with the decorative image of the decorative layer.

[0115] 35. The decorative panel (1) according to any one of the preceding clauses, wherein the panel includes a backing layer directly or indirectly attached to the bottom surface of the core layer, wherein the backing layer preferably consists of at least PET and / or PETG.

[0116] 36. The decorative panel (1) according to any one of the preceding clauses, wherein the panel includes complementary connecting profiles at at least a pair of opposing side edges, thereby allowing interconnection of adjacent decorative panels.

[0117] 37. A core layer (2) for use in a decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least partially extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) molecules based on polyethylene terephthalate (PET), wherein each molecule comprises at least two polymer chains composed of PET and / or PETG chemically bonded to each other by at least one chain extender.

[0118] 38. A core layer (2) for use in a decorative panel (1) according to any one of the preceding clauses, wherein the core layer comprises at least partially extended polyethylene terephthalate (PET) and / or extended polyethylene terephthalate (PETG) molecules based on polyethylene terephthalate (PET), wherein each molecule comprises at least two polymer chains composed of recycled PET and / or recycled PETG chemically bonded to each other by at least one chain extender.

[0119] 39. A method for producing decorative panels, particularly decorative panels (1) according to any one of the preceding clauses, comprising the following steps:

[0120] a) Mixing PET and / or PETG and / or recycled PET and / or recycled PETG materials with at least one chain extender, wherein the (recycled) PET and / or (recycled) PETG materials preferably have an intrinsic viscosity between 0.50 dl / g and 0.80 dl / g, more preferably between 0.50 dl / g and 0.60 dl / g, and / or have a molar mass between 10,000 g / mol and 20,000 g / mol;

[0121] b) The mixture is loaded into an extruder, preferably a twin-screw extruder;

[0122] c) The mixture is extruded through the extruder, preferably at a temperature between 255 and 300 degrees Celsius, wherein at least a portion of the PET and / or PETG material reacts with at least a portion of the chain extender to produce chain-extended polyethylene terephthalate (PET) and / or chain-extended polyethylene terephthalate (PETG), wherein at least two polymer chains composed of (recycled) PET and / or (recycled) PETG are chemically bonded to each other by the chain extender, wherein water is optionally produced, and wherein the core layer of the decorative panel is produced;

[0123] d) Cool the extruded core layer, preferably actively, to a temperature below 100 degrees Celsius;

[0124] e) Apply a decorative top structure over the core layer to form the decorative panel.

[0125] 40. The method according to Clause 39, wherein the mass ratio of (recycled) PET and / or (recycled) PETG to chain extender mixed during step a) is between 100:1 and 100:2.

[0126] 41. The method according to clause 39 or 40, wherein, during step a), at least two chain extenders are mixed, wherein the first chain extender is formed from at least one dianhydride, preferably pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA), and the second chain extender is formed from ADR, wherein the mass ratio of the first chain extender to the second chain extender is preferably between 1:1 and 2:1, more preferably 6:4.

[0127] 42. The method according to any one of clauses 39 to 41, wherein at least one release agent is added to a mixture of PET and / or PETG material with at least one chain extender during step a) to form a lubricating film during step c).

[0128] 43. The method according to clause 42, wherein the release agent comprises an ester group. Attached Figure Description

[0129] The invention will be described based on non-limiting exemplary embodiments shown in the following figures. In the figures:

[0130] Figure 1 A decorative panel according to the invention is illustrated schematically;

[0131] Figure 2 It shows Figure 1 The paneling has no optional intermediate layer;

[0132] Figure 3 Figure 4 schematically illustrates possible configurations of the complementary connection profile according to the present invention;

[0133] Figure 5 and Figure 6 Other possible connection profiles according to the invention are schematically shown;

[0134] Figure 7 A decorative panel according to the invention is illustrated schematically;

[0135] Figure 8 A possible example of chain extension according to the present invention is shown; and

[0136] Figure 9 Another exemplary embodiment of the chain extension according to the present invention is shown. Detailed Implementation

[0137] Figure 1 A panel (1) according to the invention is schematically shown, having a centrally located core layer (2), wherein the core layer (2) includes a top surface (3) and a bottom surface (4), preferably on opposite sides of the core layer (2). In this non-limiting embodiment, a backing layer (5) is attached to the bottom surface (4) of the core layer. Figure 1 A decorative top layer (6) is also shown, which is attached to the top surface (3) of the core layer (2). Although the decorative top structure (6) is shown as a single layer in this non-limiting embodiment, it is conceivable that the decorative top structure (6) may include more than one layer. For example, the decorative top structure (6) may be formed of: a printed decorative layer, such as a digitally printed layer, a finishing layer, or a decorative film; an embossed structure or pattern layer that may form a panel relief; and an optional abrasion-resistant layer or protective layer.

[0138] On two opposite sides (7, 8) of the panel (1)—which may alternatively be referred to as a pair of opposite edges (7, 8)—complementary connecting portions (9, 10) are provided. The first connecting portion (7) is in the form of a downward tenon (11), while the second connecting portion (9) is in the form of an upward tenon (12). The second connecting portion (9) may include a single upward tenon (12), at least one upward flank (13) located at a distance from the upward tenon, and a single upward groove (14) formed between the upward tenon and the upward flank, wherein at least a portion of the side (15) of the upward tenon facing the upward flank is inclined and extends in the direction of the normal (N1) of the upper side or top surface (3) of the core layer, and wherein optionally, at least a portion of the side (16) of the upward tenon facing away from the upward flank includes a substantially rigid first locking element (17); and on the second or fourth edge The core has a single downward tenon (11), at least one downward wing (18) located at a distance from the downward tenon, and a single downward groove (19) formed between the downward tenon and the downward wing, wherein at least a portion of the side (20) of the downward tenon facing the downward wing is inclined and extends in the direction of the normal (N2) of the lower side or bottom surface (4) of the core, and wherein the downward wing optionally includes a second locking element (21) preferably substantially rigid, the second locking element (21) being adapted to cooperate with a first locking element of the third edge of another panel.

[0139] Figure 1 Further shown is the upper or front side (22) of the upward tenon (12) sloping downward from the top side (22A) outward (16). The transition from the inner side (15) of the upward tenon (12) to the top side (22A) forms an alignment edge (23). A similar construction exists on the other side, where the upper side (24) of the groove (19) is inclined. The alignment edge (25) on the downward tenon (11) is arranged on its outer side (26). On both sides, the transition between the tenons (11, 12) and the core layer (2) is formed by bridging portions, namely an upper bridging portion (27) on the side of the downward tenon (11) and a lower bridging portion (28) on the side of the upward tenon (12). The transition portion (29) from the downward tenon (11) toward its inner side is shown as rounded to facilitate deformation.

[0140] Figure 1 This further illustrates an optional intermediate layer (30) arranged between the core layer (2) and the decorative top structure (6), while Figure 2 There is no such intermediate layer.

[0141] The core layer (2) comprises at least partially extended PET and / or extended PETG composed of molecules based on polyethylene terephthalate (PET) and / or polyethylene terephthalate (PETG), wherein each molecule comprises at least two polymer chains composed of (recycled) PET and / or (recycled) PETG, the polymer chains being chemically bonded to each other by at least one chain extender. Figure 8 The chain extension is shown in more detail below.

[0142] Figure 2 The layering of the panel (1) is schematically shown, with particular attention to the decorative top structure (6). The decorative top structure (6) includes an adhesive primer (61), a base coating (62), a transition layer (63), a printed decorative layer (64), an abrasion-resistant layer (65), a structuring layer (66), and a scratch-resistant layer (67) disposed on top.

[0143] Figure 3 Figure 4 shows other possible configurations of the complementary connection portion, which can also be used in the present invention as possible embodiments of the combination of lateral tenon and groove.

[0144] For example, Figure 3 A lateral tenon (32) is shown on a first edge, wherein the lateral tenon (32) extends in a direction substantially parallel to the top surface of the panel, the bottom front region (33) of the lateral tenon is at least partially circular, and the bottom rear region (24) of the tenon is configured as a support region, wherein the bottom rear region is closer to the level of the top surface of the panel than the lowest portion of the bottom front region; and, on the opposite second edge (8), a recess or lateral groove (35) is included for receiving at least a portion of the lateral tenon of another panel, wherein the recess is defined by an upper lip (36) and a lower lip (37), the lower lip having an upwardly projecting shoulder (38) for supporting and / or facing the support region of the lateral tenon.

[0145] Figures 4a to 4e Various variations of the shapes of the lateral tenon and groove that can be used according to the invention are shown.

[0146] Figure 5 and Figure 6 Other possible configurations of the complementary connecting portions are shown, which can also be used in the present invention as possible embodiments of downward and upward tenon combinations. Figure 5 In the middle, it is shown that... Figure 1 and Figure 2 A similar locking system, but slightly different in shape, and with additional locking elements (31) on the outside of the downward tenon (11) and on the upper side of the upward wing (13). Figure 6In the diagram, the locking element is shown as an open recess, in which the inner sides (15, 20) of the tenon (11, 12) are inclined, but not towards the core layer, but rather away from it. The angles of these inner sides (15, 20) are... Figure 1 and Figure 2 The angles shown are opposite.

[0147] Figure 7 A panel (1) is schematically shown, with its top surface (3) and side bottom surfaces (4) located on opposite sides of the core layer. The decorative panel (1) is a rectangle with four edges. The four edges are opposite edges (7, 8) on the short sides and two opposite edges (7', 8') on the long sides. Along Figure 7 The AA section shown illustrates the connecting portion on the long side, for example... Figure 3 As shown in Figure 4, the connection portion on the short side is shown along the BB section, as illustrated in other figures of this application.

[0148] Figure 8 Chain extension of a PETG chain (72) according to the invention is schematically illustrated. This mechanism is also applicable to chain extension of PET chains, as well as combinations of PETG chains and PET chains. On the left, PMDA (71) reacting with the PETG chain (72) is shown. The PETG chain (72) can be, for example, a recycled PETG chain. In this process, the ring of PDMA opens, allowing up to four PETG chains (72) to be connected at the ends to obtain a first intermediate product (73). The first intermediate product (73) can also be the final product (73), but better results may be obtained when the intermediate product (73) is used in further chain extension. The intermediate product (73) or its multiplier can then react with an ADR group (74). The free ends of the PETG chain (72) that are not connected to the ends of the PMDA (71) and therefore the intermediate product (73) then react with the ADR group (74) to form an ADB backbone having preferably multiple intermediate products (73) for further chain extension.

[0149] The reaction products of PMDA may be four-armed star polymers, and the branching reaction with ADR may form comb-shaped PETG with a very short backbone. The backbone is considered relatively short because PETG (26300 g / mol) is approximately nine times the average molar mass of ADR (3000 g / mol). Depending on the reaction mechanism, ADR is more likely to induce branched structures than PMDA because ADR can achieve branching in just one step, while PMDA requires two steps, especially since the secondary esterification or transesterification reaction of PMDA is relatively slow. This can be confirmed by the short reaction time of ADR during batch mixing.

[0150] Figure 9 As shown Figure 8 An alternative example of chain extension is shown. The figure illustrates the reaction of the ADR group (74) with the PETG chain (72). In the final product (75), the PETG chain (72) has been attached to the ADR group (74). It is also conceivable that a chain extension can be formed as shown in the figure. Figure 8 and Figure 9 The chain extension combination shown includes a combination of a PETG chain (72) and an intermediate product (73) attached to an ADR group (74). This mechanism also applies to chain extension of at least one PET chain, as well as combinations of at least one PETG chain and at least one PET chain.

[0151] It is obvious that the invention is not limited to the working examples shown and described herein, but many variations may be apparent to those skilled in the art within the scope of the appended claims.

[0152] The ordinal numbers used herein, such as "first," "second," "third," and "fourth," are for identification purposes only. Therefore, the use of the term "third connecting profile" does not necessarily require the simultaneous presence of a "first connecting profile." Similarly, the use of the terms "third locking element" and "second locking element" does not necessarily require the simultaneous presence of a "first locking element." "Horizontal" refers to a direction extending parallel to the plane defined by the tile panel, and this direction may intersect with the core layer of the tile panel. "Vertical" refers to a direction perpendicular to the plane defined by the tile panel. "Complementary" connecting profiles refer to connecting profiles of adjacent tile panels that can fit together. However, complementary connecting profiles do not necessarily have to be completely complementary (reverse designs). "Proximal" refers to the side closest to the body of the tile panel, while "farthest" refers to the side farther from the body of the tile panel than the proximal side. The proximal side may face the body of the tile panel, while the farthest side may face away from the body of the tile panel.

[0153] In the foregoing, the designation PET can be optionally replaced by at least one other suitable condensation polymer, particularly copolymers of polyester and / or PET and / or derivatives of PET such as PETG (polyethylene terephthalate), wherein the PET copolymer comprises, for example, at least one comonomer selected from diethylene glycol (DEG), cyclohexanediol (CHDM), isophthalic acid (IPA), and naphthalic acid (NDC), and mixtures of at least two of these comonomers. PETG is a variant of PET, where "G" stands for ethylene glycol, which is added at the molecular level to provide different chemical properties and is therefore considered a copolymer of PET. Compared to (virgin or recycled) PET, (virgin or recycled) PETG has greater strength and durability, is more impact-resistant, and is better suited for high temperatures, thus making it a suitable alternative to PET.

[0154] As previously stated, in this invention, recycled PET can be replaced by recycled PETG (or vice versa) and / or virgin PETG (or vice versa), or by a combination of recycled PETG and virgin PETG (or vice versa). In this invention, virgin PET can be replaced by recycled PETG (or vice versa) and / or virgin PETG (or vice versa), or by a combination of recycled PETG and virgin PETG (or vice versa). The combination of (recycled and / or virgin) PET and (recycled and / or virgin) PETG can also be used in at least one panel layer, such as a core layer. It is conceivable that (recycled and / or virgin) PET is used in at least one panel layer, while (recycled and / or virgin) PETG is used in at least one other panel layer. It is conceivable that multiple panel layers contain PETG, such as a core layer, at least one abrasion layer, and / or at least one intermediate layer (intermediate film) located between said core layer and at least one abrasion layer. The PETG-based material used in at least one panel layer can be foamed or unfoamed (solid). In particular, the PETG-based core layer can be a foamed PETG-based core layer to save weight.

[0155] In this invention, the foaming regulator preferably acts as a chain extender. The foaming regulator preferably comprises a polymer, preferably acrylate-based, having (reactive) epoxy groups and / or ester groups. The presence of ester groups provides good compatibility for achieving uniform mixing of the foaming regulator with PET (and / or PETG). The reaction between the foaming regulator and the polymer chains of PET and / or PETG extends the molecular weight of PET and / or PETG and significantly improves the melt strength of the mixture. Furthermore, acrylate-based foaming regulators have relatively good compatibility with inorganic fillers. Each epoxy group of the foaming regulator (chain extender) is capable of reacting with a hydroxyl group (carboxyl-terminal group) to form an ester. When the foaming regulator molecule contains multiple epoxy groups, multiple PET (and / or PETG) chains can bind to the foaming regulator molecule, thus these chains can bind to each other, effectively leading to chain extension.

[0156] In this invention, the amount of foaming agent in the raw material composition is preferably kept limited, for example, 1 part relative to 100 parts PET (and / or PETG). This results in sufficient foaming to reduce the layer density (e.g., at 0.8 g / cm³). 3 Up to 1.0 g / cm 3 Between and containing 0.8g / cm 3 and 1.0 g / cm 3This reduces panel weight while maintaining sufficient (bending) strength, such as at least 180 MPa, and typically results in a relatively high noise reduction factor of at least 0.95, which is preferably measured according to ASTM C423(-23) standard.

[0157] In this invention, the inorganic filler is preferably or more preferably a mixture of calcium carbonate (limestone) and talc, wherein the mass ratio of calcium carbonate to talc is preferably (1-9):(9-1), more preferably 1:1. In some embodiments of this invention, the inorganic filler may have a particle size of 200 to 400 mesh.

[0158] The verb “comprising” and its variations used in this patent publication should be understood not only to mean “including”, but also to mean the phrases “containing,” “substantially constituted by,” “formed by,” and their variations.

Claims

1. A decorative panel (1), particularly a decorative floor panel, a decorative ceiling panel, or a decorative wall panel, said decorative panel (1) comprising: At least one core layer (2); A decorative top structure (6) directly or indirectly fixed to the top surface of the core layer (2); The at least one core layer (2) comprises at least partially extended polyethylene terephthalate (PETG) molecules, wherein each molecule comprises at least two polymer chains composed of PETG, the polymer chains being chemically bonded to each other by at least one chain extender.

2. The decorative panel (1) according to claim 1, wherein, At least a portion of the PETG-based molecules comprise at least four polymer chains composed of PETG that are chemically bonded to each other by at least one chain extender.

3. The decorative panel (1) according to any one of the preceding claims, wherein, At least a portion of the PETG-based molecule contains recycled PETG.

4. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially extended polyethylene terephthalate (PETG) composed of PETG-based molecules, wherein each molecule comprises at least one polymer chain composed of recycled PETG and at least one polymer chain composed of virgin PETG, which are chemically bonded to each other by at least one chain extender.

5. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially PETG composed of PETG-based molecules, wherein each molecule comprises at least two polymer chains composed of recycled PETG that are chemically bonded to each other by at least one chain extender.

6. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) contains unbonded recycled PETG and / or unbonded virgin PETG.

7. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises unbonded recycled polyethylene terephthalate (PET) and / or unbonded virgin PET, and / or the core layer (2) comprises unbonded recycled PETG and / or unbonded virgin PETG.

8. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) contains unbonded chain extender molecules.

9. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially extended polyethylene terephthalate (PETG) composed of PETG-based molecules, wherein each molecule comprises at least two polymer chains composed of PETG chemically bonded to each other by at least two different chain extenders.

10. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially extended polyethylene terephthalate (PETG) composed of PETG-based molecules, wherein each molecule comprises at least two polymer chains composed of recycled PETG chemically bonded to each other by at least two different chain extenders.

11. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially extended polyethylene terephthalate (PET) composed of PET-based molecules, wherein each molecule comprises at least two polymer chains composed of PET that are chemically bonded to each other by at least two different chain extenders.

12. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer (2) comprises at least partially extended polyethylene terephthalate (PET) composed of PET-based molecules, wherein each molecule comprises at least two polymer chains composed of recycled PET that are chemically bonded to each other by at least two different chain extenders.

13. The decorative panel (1) according to any one of the preceding claims, wherein, At least one chain extender comprises a multifunctional epoxide oligomer.

14. The decorative panel (1) according to claim 13, wherein, The multifunctional epoxide oligomer (ADR) is represented by the following chemical structure before being bonded to the PETG chain: in: R1 to R5 are H, CH3, higher alkyl groups or combinations thereof; R6 is an alkyl group; and x, y, and z are each between 1 and 20.

15. The decorative panel (1) according to any one of the preceding claims, wherein, Prior to bonding with the PETG chain, at least one chain extender comprises at least one dianhydride, preferably pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA).

16. The decorative panel (1) according to claims 14 and 15, wherein, The core layer comprises: (i) at least one dianhydride, preferably a mixture of pyromellitic dianhydride (PMDA) and / or trimellitic dianhydride (MEDA) and (ii) ADR, wherein preferably, the mass ratio of the dianhydride to the ADR is between 1:1 and 2:1; more preferably, the mass ratio is 6:

4.

17. The decorative panel (1) according to claim 13 or 14 and claim 15 or 16, wherein, At least some of the PET-based molecules each contain: Multiple clusters, wherein each cluster comprises multiple polymer chains composed of PETG chemically bonded to each other via dianhydrides, preferably via PMDA and / or MEDA; The clusters are chemically bonded to each other through the multifunctional epoxide oligomers.

18. The decorative panel (1) according to any one of the preceding claims, wherein, The decorative panel includes multiple panel layers, such as a core layer, at least one abrasion layer, and / or at least one intermediate layer between the core layer and at least one abrasion layer, wherein at least one panel layer contains recycled PETG and / or virgin PETG, and wherein at least one other panel layer contains recycled PET and / or virgin PET.

19. The decorative panel (1) according to any one of the preceding claims, wherein, The panel comprises a plurality of laminated core layers, wherein at least one core layer and preferably each core layer contains PETG, more preferably extended chain PETG; wherein the panel comprises three laminated core layers in an ABA configuration, wherein the outer layer (A) has the same composition, while the inner layer (B) has a different composition.

20. The decorative panel (1) according to any one of the preceding claims, wherein, The decorative panel includes multiple panel layers, such as a core layer, at least one abrasion-resistant layer, and / or at least one intermediate layer located between the core layer and the at least one abrasion-resistant layer, wherein at least one panel layer, and preferably the core layer, includes a foamed PETG layer and / or a foamed PET layer.

21. The decorative panel (1) according to claim 20, wherein, The foamed PETG layer and / or foamed PET layer contains at least one foaming agent, such as azodicarbonamide (AC) foaming agent (foaming agent), and / or at least one foaming modifier, such as acrylate (ACR) foaming modifier.

22. The decorative panel (1) according to any one of the preceding claims, wherein, The average molar mass of each bonded PETG chain is less than 20,000 g / mol, preferably less than 15,000 g / mol, and more preferably less than 12,000 g / mol.

23. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer comprises at least one inorganic filler, such as limestone, and / or an organic filler, such as wood particles; wherein the amount of filler in the core layer is at least 50% of the weight of the core layer, preferably 60% to 70% of the weight of the core layer.

24. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer contains at least one lubricant formed from silicone oil, and preferably, the amount of the lubricant is less than 1% of the weight of the core layer.

25. The decorative panel (1) according to any one of the preceding claims, wherein, The core layer contains at least one toughening agent, the amount of which is preferably less than 10% of the weight of the core layer, more preferably 3% to 8% of the weight of the core layer.

26. The decorative panel (1) according to any one of the preceding claims, wherein, The decorative top structure includes at least one decorative layer applied directly or indirectly to the top surface of the core layer, and preferably includes at least one additional layer applied to the decorative layer, such as a wear-resistant layer and / or a scratch-resistant layer.

27. The decorative panel (1) according to any one of the preceding claims, wherein, The panel includes complementary connecting profiles at at least a pair of opposite side edges, thereby allowing the interconnection of adjacent decorative panels.

28. A core layer (2) for use in a decorative panel (1) according to any one of the preceding claims, wherein, The core layer comprises at least partially extended polyethylene terephthalate (PETG) molecules, wherein each molecule comprises at least two polymer chains composed of PETG chemically bonded to each other by at least one chain extender.

29. A method for producing decorative panels, particularly decorative panels (1) according to any one of claims 1 to 27, comprising the following steps: a) Mixing PETG material with at least one chain extender, wherein the PETG material preferably has an intrinsic viscosity between 0.50 dl / g and 0.80 dl / g, more preferably between 0.50 dl / g and 0.60 dl / g, and / or has a molar mass between 10,000 g / mol and 20,000 g / mol; b) The mixture is loaded into an extruder, preferably a twin-screw extruder; c) The mixture is extruded through the extruder, preferably at a temperature between 255 and 300 degrees Celsius, wherein at least a portion of the PETG material reacts with at least a portion of the chain extender to produce chain-extended polyethylene terephthalate (PETG), wherein at least two polymer chains composed of PETG are chemically bonded to each other by the chain extender, wherein water is optionally produced, and wherein the core layer of the decorative panel is produced; d) Cool the extruded core layer, preferably actively, to a temperature below 100 degrees Celsius; e) Apply a decorative top structure over the core layer to form the decorative panel.

30. The method according to claim 29, wherein, During step a), at least one release agent is added to a mixture of PETG material and at least one chain extender to form a lubricating film during step c).

31. The method according to claim 30, wherein, The release agent contains ester groups.

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