CN119731018A

CN119731018A - Decorative panel and method for producing a decorative panel

Info

Publication number: CN119731018A
Application number: CN202380060612.7A
Authority: CN
Inventors: 本尼·沙赫特; 本杰明·克莱门特
Original assignee: Unilin BV
Current assignee: Unilin BV
Priority date: 2022-08-26
Filing date: 2023-06-23
Publication date: 2025-03-28
Also published as: WO2024042380A1; EP4577405A1; CA3264341A1

Abstract

Decorative panel comprising a substrate (2) and a top layer (3) provided thereon, wherein the substrate (2) comprises at least a semi-crystalline polymer (4), characterized in that the decorative panel (1) exhibits one or a combination of two or more of the properties of-a property of the polymer having a crystallinity of less than 85%, a property of the polymer having a crystallinity of more than 35%, preferably more than 50%, as measured using differential scanning calorimetry, -a property of the polymer being uniaxially oriented, -the top layer comprising a semi-crystalline polymer, wherein the crystallinity of the polymer comprised in the substrate (2) is lower than the property of the polymer comprised in the decorative top layer (3), -the substrate (2) comprises a plurality of substrate layers, wherein at least two of the plurality of substrate layers comprise the property of the semi-crystalline polymer (4).

Description

Decorative panel and method for producing a decorative panel

Technical Field

The present invention relates to a decorative panel and a method for manufacturing a decorative panel. The decorative panel of the invention is first suitable for application as a floating floor panel, but may also be applied in other ways, for example as a glued floor panel, or as a wall or ceiling panel.

Background

WO 97/47834 describes a laminate floor panel for assembling a floating floor covering. As described therein, the floor panels have the disadvantage that the substrates used, more particularly MDF or HDF substrates (medium density fiberboard or high density fiberboard), are vulnerable to moisture. The laminated top layer may give off a walk and/or click.

EP 1 938 963 discloses floors based on synthetic materials, more particularly soft Polyvinylchloride (PVC). The floor can be obtained at least by laminating several synthetic foils. EP 3 405 346 discloses a floor panel filled with a polyvinyl chloride material at high density. The floor panel may be obtained at least by extrusion. In both EP '963 and EP'346, the floor is provided with a decorative top layer comprising PVC. The floor panels of EP '963 and EP '346 may be more waterproof than the panels of WO '834 and/or provide more comfortable walking and/or ticking. However, the use of PVC, plasticizers and/or other additives, at least in some cases, can be harmful to the environment.

From WO 2017/122149 it is known to use PET (polyethylene terephthalate) compositions as a substrate in floor panels, wherein the substrate can be formed at least by extrusion. From WO 2014/111192 it is known to use thermoplastic compositions comprising PP (polypropylene) as a substrate in decorative panels. Panels comprising substrates employing PET or PP may be particularly susceptible to deformation under varying environmental conditions due to their crystallinity.

Disclosure of Invention

The present invention seeks first to provide an alternative trim panel in which, according to a preferred embodiment, a solution is provided to one or more of the problems of the trim panels of the prior art.

To this end, according to a first independent aspect thereof, the present invention is a decorative panel comprising a substrate and a top layer provided thereon, wherein the substrate comprises at least a semi-crystalline or crystalline polymer and/or a polymer selected from the list consisting of Polyacetal (POM), polyphenylene sulphide (PPS), polyamide (such as PA 6 and PA 66), polyethylene terephthalate (PET), ethylene glycol modified PET (PETG), polycyclohexane dimethyl terephthalate (PCT), ethylene glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalate (PCTA), polyethylene (PE), low Density Polyethylene (LDPE) (e.g. Linear Low Density Polyethylene (LLDPE)), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT), polylactic acid (PLA), polyetheretherketone (PEEK) and polypropylene (PP), characterized in that the decorative panel shows a combination of one or two or more of the following properties.

According to a first possible property, the crystallinity of the polymer is lower than 95% or lower than 85%, preferably measured using Differential Scanning Calorimetry (DSC) according to ISO 11357-3:2018. By defining the crystallinity, the dimensional instability of the trim panel as a whole can be kept within acceptable limits.

According to a second possible property, the crystallinity of the polymer is higher than 35%, preferably higher than 50%, preferably measured using Differential Scanning Calorimetry (DSC) according to ISO 11357-3:2018. Allowing for minimal crystallinity may be advantageous for toughness, tensile strength, and chemical resistance of the substrate. The first and second possible properties are preferably combined so that an optimized crystallinity is obtained according to the desired properties of the decorative panel, e.g. a floor panel, while maintaining good dimensional stability.

According to a third possible property, the polymer is uniaxially oriented, or at least oriented in one direction. The polymer chains are oriented predominantly in at least one direction, possibly resulting in an increase in tensile strength in the respective direction. Preferably the direction of orientation coincides or substantially coincides with the largest dimension of the trim panel. For example, in the case of rectangular (rectangular) and oblong (elongated) panels, the orientation direction preferably coincides or substantially coincides with the longitudinal direction of the trim panel. In this case, the stress due to dimensional instability can be optimally handled, since it can be expected that the shrinkage or expansion will be greatest in the longitudinal direction. When this third property is practiced in combination with at least the first possible property and potentially the second possible property, the remaining properties (expected to be dimensional instability) can be managed.

Dimensional instability can be further limited by the use of filler materials, for example, by the use of wollastonite, mica, aluminum silicate, and/or glass, preferably in fiber form, and/or by the use of thermomechanical pulp fibers (thermochemical pulp fiber). Preferably, the filler material is anisotropic in terms of its mechanical properties, in particular its tensile strength. Preferably the filler material is generally oriented such that its direction of maximum tensile strength is consistent or substantially consistent with the direction of orientation of the semi-crystalline or crystalline polymer and/or with the longitudinal direction of rectangular and oblong trim panels. Preferably the ratio of tensile strength values in the orthogonal direction of the filler material is at least 125%, or at least 200%.

According to a fourth possible property, the top layer comprises a crystalline or semi-crystalline polymer, wherein the crystallinity of the polymer comprised in the substrate is lower than the crystallinity of the polymer comprised in the decorative top layer and vice versa. Preferably the difference in crystallinity between the polymer in the decorative top layer and the polymer in the substrate is at least 5% or at least 10%. This property limits the possible dimensional changes, especially when the layer with the greatest crystallinity and thus the layer with the highest expected dimensional instability, such as a decorative top layer, may and preferably is thinner than the substrate. According to a fourth possible property, the substrate can thus stabilize the decorative top layer to a certain extent and vice versa. Preferably the decorative panel further comprises a layer at the bottom of the substrate, wherein the layer further comprises a semi-crystalline or crystalline polymer and preferably has a higher crystallinity than the substrate and vice versa. In this case, the layer may counteract to some extent any warping effect of the different (e.g. higher) dimensional instability of the decorative top layer compared to the substrate. Preferably, the crystallinity of the layer applied to the bottom of the substrate is the same as or within 10% or 5% of the crystallinity of the decorative top layer, and/or the thickness of the layer applied to the bottom surface of the substrate is the same as or within 10% or 5% of the thickness of the decorative top layer. In this case, an optimal equalization effect can be obtained. This fourth possible property is preferably combined with the first, second and/or third property. Preferably the decorative top layer and/or the layer applied to the bottom of the substrate contains a crystalline or semi-crystalline polymer that is at least monoaxially oriented, but preferably biaxially oriented. The decorative top layer and/or the layer applied to the bottom of the substrate may comprise, for example, oriented polypropylene or polyethylene foil. In the case of this fourth possible property at least in combination with said third possible property, the polymers of the decorative top layer and/or of the bottom layer may be oriented at least in a direction perpendicular to the orientation of the semi-crystalline polymers contained by said substrate, wherein the orientation of the semi-crystalline polymers contained by said substrate is preferably monoaxially oriented or oriented mainly in a single direction. For example, in the case of rectangular and oblong panels, the base polymeric material may be oriented at least or predominantly in the machine direction, while the decorative layer and/or the base layer may comprise a foil biaxially oriented in the machine and transverse directions of the panel. In this case, the combination of the third and fourth possible properties produces a desirable synergistic effect in terms of an enhanced dimensional stability of the trim panel as a whole.

The decorative top layer preferably comprises a foil with a printed ink pattern. Preferably at least the foil comprises a crystalline or semi-crystalline polymer according to the fourth possible property. The decorative top layer preferably further comprises an abrasion resistant layer applied on top of the printed ink pattern. The wear layer preferably comprises an amorphous polymer or a polymer having a crystallinity of less than 35% or less than 10%. Preferably the polymer of the wear layer is of the same type as the polymer of the foil. For example, the wear layer may comprise amorphous or random polypropylene, while the foil comprises semi-crystalline, crystalline or syndiotactic or isotactic polypropylene, e.g., having an isotactic index of 85% to 95%. The isotactic index can be measured in accordance with DIN 16774, for example, by determining the fraction of polymer insoluble in boiling heptane.

According to a specific embodiment, the decorative top layer comprises a printed foil, for example a polypropylene printed foil, and a transparent wear layer cast thereon, the wear layer comprising polypropylene, which is preferably embossed.

According to a specific possible property, the decorative panel comprises a top layer and/or a layer applied to the bottom of the substrate, wherein the top layer and/or bottom layer comprises amorphous polypropylene or polypropylene having a crystallinity of 35% or less, and/or wherein the top layer and/or bottom layer is obtained by casting polypropylene. This particular property may minimize warpage effects caused by the top and/or bottom layers. For example, the top layer may comprise cast PP, such as cast PP foil, and provided thereon with a decorative printed and/or wear layer comprising cast PP, such as cast PP film. Such cast PP is predominantly unoriented and minimizes the occurrence of directional stability effects caused by the top layer. Preferably the bottom layer further comprises cast PP, for example cast PP foil. Preferably, the wear layer comprising PP according to specific properties of the present invention further comprises an amorphous polymer or copolymer, such as a cyclic olefin polymer or copolymer (COP or COC). Such blends of PP and amorphous polymers or copolymers may improve the clarity of the abrasion resistant layer.

According to a fifth possible property, the substrate comprises a plurality of substrate layers, wherein at least two of the plurality of substrate layers comprise a semi-crystalline polymer and/or a polymer selected from the list consisting of Polyacetal (POM), polyphenylene sulfide (PPS), polyamides (such as PA 6 and PA 66), polyethylene terephthalate (PET), glycol modified PET (PETG), polycyclohexane dimethyl terephthalate (PCT), glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalate (PCTA), polyethylene (PE), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT), polyetheretherketone (PEEK) and polypropylene (PP). Such polymers are arranged in multiple layers within the substrate so as to optimally address any adverse effects, such as shrinkage and/or expansion. Preferably the semi-crystalline polymers in the at least two substrate layers are identical, or at least built up from identical monomers. Preferably, the other components of the respective two substrate layers are similar or identical and are present in similar or identical amounts. For example, both substrate layers may contain filler material (preferably in the same or substantially the same ratio). Preferably, in said fifth property, said at least two substrate layers are separated from each other by an additional layer comprising a polymer (semi-crystalline or crystalline polymer or another polymer, such as PVC). Alternatively or in combination, the at least two substrate layers may be separated by at least one reinforcing layer, or may include reinforcing layers at their mutually interface surfaces. Preferably, in said fifth property, the number of polymer-containing substrate layers is preferably an odd number, for example, three or five. Preferably, the at least two substrate layers comprising semi-crystalline or crystalline material are positioned with at least one of their main surfaces equidistant or substantially equidistant from the center of the substrate as seen in the thickness direction. Preferably, the at least two substrate layers comprising the semi-crystalline or crystalline material have equal thickness, or substantially equal thickness, e.g. having a thickness difference wherein the thinnest layer is at least 90% of the thickest layer thickness.

According to A particularly preferred embodiment of the fifth possible nature, the at least two substrate layers may be comprised in A substrate having substantially the A-B or A-B-A configuration, wherein A represents A layer having A first composition and B represents A layer having A second composition. As explained in the context of the fifth possible property, the two substrate layers may have the same or similar composition, or have mutually different compositions, and thus may each form an a layer, or one of the two substrate layers forms an a layer and the other forms a B layer. For example, the two substrate layers may have mutually different compositions, for example the composition differences being at least or mainly related to different filler contents. In practice, the substrate layer may comprise a first substrate layer having a first composition comprising a semi-crystalline or crystalline material and/or a polymer selected from the list consisting of Polyacetal (POM), polyphenylene sulfide (PPS), polyamide (such as PA 6 and PA 66), polyethylene terephthalate (PET), ethylene glycol modified PET (PETG), polycyclohexane dimethyl terephthalate (PCT), ethylene glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalate (PCTA), polyethylene (PE), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT), polyetheretherketone (PEEK) and polypropylene (PP), and a first content of a filler material (such as a first composition having a weight ratio of filler to polymer greater than 1.5:1, or even 2:1, 2.5:1 or more), and a second substrate layer having a second composition comprising a semi-crystalline or crystalline material and/or a polymer selected from the list consisting of Polyacetal (PCTG), polyphenylene sulfide (PPS), polyamide (such as 6 and 66), polyethylene terephthalate (PE), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT), polyetheretherketone (PEEK) and polypropylene (PP), and a second content of filler material (such as a first composition having a weight ratio of filler to polymer greater than 1.5:1, or even 2:1, 2.5:1 or more A second substrate layer of a second composition of a list of polymers of Polyetheretherketone (PEEK) and polypropylene (PP) and a first amount of filler material (e.g., a filler to polymer weight ratio of 1.5:1 or less). The polymers of the two sublayers may be the same, for example, both polypropylene or both PET or both PETG. Preferably the substrate consists essentially of or consists of the two sublayers, thereby obtaining a substrate having an a-B configuration, wherein the a layer or a first layer formed from the first composition is preferably closer to the top layer than the B layer or a second layer formed from the second composition, and/or wherein the a layer constitutes more than half the thickness of the substrate. The inventors have noted that this particular combination of highly filled substrate layers with less filled substrate materials is particularly advantageous for minimizing warpage effects due to polymer crystallinity.

In the fifth possible property, and in other embodiments where the substrate comprises a plurality of substrate layers, these layers may be adhered to each other, thermally laminated, coextruded or hardened on top of each other, an intermediate layer of primer layer or adhesive layer may be employed, as further described herein. Any combination of these techniques may be suitable for the substrate layer.

Preferably the semi-crystalline or crystalline polymer is a thermoplastic polymer.

When the polymer is a polypropylene, such as a semi-crystalline or crystalline polypropylene, it is preferred to use a polypropylene having an isotactic index of 85% to 95%. The isotactic index can be measured in accordance with DIN 16774 by, for example, determining the fraction of the polymer insoluble in boiling heptane.

The substrate or the corresponding substrate layer comprising the semi-crystalline polymer preferably consists of, or essentially consists of, such filled synthetic material, for example consisting of more than 85 wt%. In this case, the synthetic material is preferably formed mainly or exclusively of said semi-crystalline or crystalline polymer, for example in an amount exceeding 85%, wherein said semi-crystalline or crystalline polymer is preferably a thermoplastic polymer or of a polymer selected from the list consisting of Polyacetal (POM), polyamide (PA 6 and PA 66), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), ethylene glycol modified polyethylene terephthalate (PETG), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polyphenylene sulphide (PPS) and polypropylene (PP).

As an alternative to or in combination with the polymers already mentioned, the substrate or the respective layer may comprise at least a thermoplastic elastomer, such as a polymer or copolymer, for example a styrene block copolymer, wherein the polymer or copolymer comprises or consists of Ethylene Propylene Diene Monomer (EPDM), styrene Ethylene Butadiene Styrene (SEBS), poly (styrene butadiene styrene) (SBS), polyether block amide (PEBA), thermoplastic Polyurethane (TPU), styrene Ethylene Propylene Styrene (SEPS), styrene ethylene propylene styrene (SEEPS), acrylonitrile Ethylene Styrene (AES) or Polybutadiene (PB), preferably in semi-crystalline or crystalline form and/or according to the first to fifth and specifically possible properties mentioned above. Alternatively, the substrate or the respective layer may comprise at least Polystyrene (PS) (preferably atactic polystyrene), ABS, neoprene or polyvinyl alcohol (PVAC), preferably in semi-crystalline or crystalline form and/or according to the first to fifth and particularly possible properties mentioned above.

The substrate may include a reinforcing layer, such as a woven or nonwoven layer of glass fibers. The semi-crystalline or crystalline polymer may be continuous through the openings of the reinforcing layer, such as through alternating woven layers of glass fibers, such as woven layers having a network of glass fibers extending in at least two intersecting directions.

Preferably, the semi-crystalline polymer is selected from the list consisting of Polyacetal (POM), polyamide (PA 6 and PA 66), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glycol modified PET (PETG), polycyclohexane dimethyl terephthalate (PCT), glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalate (PCTA), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polyphenylene sulfide (PPS) and polypropylene (PP). The semi-crystalline polymer may be a homopolymer or a heteropolymer, preferably having a main component of one of Polyacetal (POM), polyamide (PA 6 and PA 66), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polyphenylene sulfide (PPS) and polypropylene (PP).

It should be noted that PETG, PCT, PCTG or PCTA may be preferred for improved resistance to indentation (indentation resistance) and optimal resistance to delamination.

Preferably the polymer, semi-crystalline polymer or crystalline polymer used in the first aspect is a polypropylene polymer. The polypropylene may be a homopolymer or a heteropolymer, the main component of which is polypropylene. For example, the semi-crystalline polymer may be polypropylene copolymerized with ethylene, such as with 15wt% or less of ethylene. In one specific example, the polypropylene is copolymerized with 3wt% or about 3wt% ethylene. Copolymerization with ethylene may result in a smoother material processing, such as smoother extrusion. In addition, copolymers, such as copolymers with ethylene, can affect the amount or rate of crystallization. With higher crystallization speeds, the heating capacity required in the production to obtain the desired crystals can be reduced. This is especially true in the case of polypropylene copolymers having a low ethylene content, for example less than 15 wt.%, less than 10 wt.% or even less than 5 wt.%. Preferably PP can be blended with the co [ poly (butylene terephthalate-p-oxybenzoate) ] copolyester, e.g. at a copolyester content of 5wt% to 15wt%, to produce the ethylene-propylene copolymer of interest. Alternatively, PP may be blended with an amorphous polymer or copolymer, for example with a cyclic olefin polymer or copolymer (COP or COC). The use of amorphous polymers or copolymers in blends with PP may result in better melt flow (e.g., in an extruder), and/or enhanced thermal stability of the substrate.

Preferably the polymer, semi-crystalline polymer or crystalline polymer used in the first aspect is a heteropolymer, preferably comprising ethylene and propylene. The polymer may be, for example, polyethylene copolymerized with polypropylene, for example, with 15wt% or less propylene. According to another example, the semi-crystalline or crystalline polymer is a propylene-ethylene random copolymer (PP-R).

Preferably the substrate comprises a filled synthetic material, wherein the filled synthetic material is formed at least from the semi-crystalline or crystalline polymer and a filler material. Three variants are mainly envisaged for the filler material.

According to a first variant, the filler material has a density of 300kg/m ³ or less, for example 120-180kg/m ³, and/or comprises a material selected from the list consisting of rice hulls, cork, bamboo, sugar cane, foamed synthetic materials, porous inorganic materials, perlite (preferably expanded perlite), vermiculite (preferably expanded or exfoliated vermiculite), celeite (cenolite) and pumice. Such filler materials may limit the density of the resulting substrate material. Preferably the filler material is present in particulate form. According to a variant, the filler, such as bamboo and sugar cane, may be present in the form of fibers. In this case, the fibers may mechanically reinforce the semi-crystalline or crystalline material. Preferably at least 10% weight loss, even at least 35%. It is not excluded that a weight reduction of 50% or more is obtained. In said first variant, it is preferred that the amount of filler material available in said filled synthetic material is expressed by the weight ratio of filler to synthetic material in the range of 5% to 25%. For example, in a filled polypropylene substrate, 15% 150kg/m ³ filler, such as 15% exfoliated vermiculite (exfoliated vermiculite), may be applied. Extracted from a few possible additives and the density of polypropylene is 920kg/m ³, which means that about 48% of the volume of the filled synthetic material consists of the filler and the total density is 550kg/m ³. A weight saving of 370/920 or about 40% is obtained here. The use of a lightweight filler material in view of the weight saving that is obtainable also draws attention to other trim panels than the trim panel of the first independent aspect, and thus constitutes a specific independent aspect of the invention itself, which is a trim panel comprising a substrate and a top layer provided thereon, wherein the substrate comprises at least a filled synthetic material, wherein the filled synthetic material is formed of at least a preferably thermoplastic polymer and a filler material, characterized in that the filler material comprises a filler material having a density of 300kg/m ³ or less, for example 120-180kg/m ³, and/or is selected from the group consisting of rice hulls, Cork, bamboo, sugar cane, foamed synthetic materials, porous inorganic materials, perlite, vermiculite, celecoxite, and pumice. It will be apparent that preferred embodiments of this particular independent aspect may exhibit the features of the preferred mode of the first aspect, while the polymer need not be a crystalline or semi-crystalline polymer. For example, the polymer may also be polyvinyl chloride (PVC). According to a preferred embodiment, all or at least 75vol% or at least 85vol% of the filler material in the specific, stand-alone aspect of the filled composite material is a light weight filler material.

According to a second variant, the filler material has a density higher than the polymer, or a density of 1200kg/m ³ or higher, for example a density of 1800-3000kg/m ³, and/or the filler material comprises a material selected from the list consisting of chalk, talc, limestone, caCO ₃, sand and SiO ₂. It should be noted that as mentioned above, the high weight filler material has a further stabilizing effect on possible dimensional instabilities and can more easily hold the trim panel in its installed position. In said second variant, it is preferred that the amount of filler material available in said filled synthetic material is expressed by the weight ratio of filler to synthetic material in the range of 100% to 450%. For example, in a filled polypropylene substrate, 400% 2500kg/m ³ filler, such as 400% chalk, may be applied. Extracted from a few possible additives and polypropylene has a density of 920kg/m ³, which means that about 60% of the volume of the filled synthetic material is formed by the filler, whereas the total density is 2045kg/m ³. Notably, such highly filled polypropylene materials are lighter in weight than similar filled polyvinyl chloride materials, and thus may help limit transportation costs and improve installer ergonomics. This is also possible for high filled polyethylenes such as high filled LDPE or HDPE.

It should be noted that it is possible and not necessarily not necessary to create strength problems to replace high volumes in the synthetic material, for example more than 20vol% or more than 40vol% of semi-crystalline or crystalline polymers, such as PP (possibly copolymers thereof), with low or high weight fillers (for example fillers having a density lower than 250kg/m ³ or higher than 2000kg/m ³). This is especially true in the case of practicing the aforementioned second and/or third possible properties of the present invention. A relatively high crystallinity and/or orientation of the polymer in at least one direction is advantageous herein. Furthermore, the high volume content of filler can limit dimensional instability.

In the first and second variants, according to a preferred embodiment thereof, all or at least 75vol% or at least 85vol% of the filled synthetic material is a light weight filler material, a correspondingly high weight filler material.

According to a third variant, the filler material comprises a part of the low weight filler material as described in the first variant and a part of the high weight filler material as described in the second variant. Preferably, the density of such filler material is within 25% of the density of the semi-crystalline or crystalline polymer, preferably within 20% of the density of the semi-crystalline or crystalline polymer. For example, a polypropylene having a density of 920kg/m ³ may comprise a filler material mixture having a density of 690kg/m ³-1150 kg/m³, preferably 736kg/m ³-1104 kg/m³. For example, such filler material may have 33.3vol% or one third of filler material having a density of 2500kg/m ³, such as chalk, and 66.6vol% or two thirds of filler material having a density of 150kg/m ³, such as exfoliated vermiculite. The total density of this filler material is 933kg/m ³, of which 89.3% by weight consists of high-weight filler, in this example chalk.

In said third variant, it is preferred that the amount of filler material available in said filled synthetic material is expressed by the weight ratio of filler to synthetic material in the range 50% to 250%, or preferably 80% to 200%. Preferably the density of the filled semi-crystalline or crystalline polymer is within 30% or 20% of the envisaged density of the polymer. In the case of 920kg/m ³ of polypropylene, the density of the filled polypropylene material is preferably 644-1196kg/m ³, or 736-1104kg/m ³.

As an example of a third variant, in a filled polypropylene substrate, the above 933kg/m ³ filler material may be applied in a ratio of 150%. Extracted from a few possible additives and the density of polypropylene is 920kg/m ³, which means that about 60% of the volume of the filled synthetic material consists of the filler, giving a total density of 928kg/m ³. Notably, the weight of such highly filled polypropylene materials is about the same as the unfilled polypropylene materials, while still achieving acceptable mechanical strength. In this case, the material saving of the polymer material does not have a negative impact on ergonomics and transportation costs. It is obvious that in the case of such filled polyethylenes (e.g. filled LDPE or HDPE) it is also possible to obtain highly filled synthetic materials having a density substantially identical to the polymer contained in the filled synthetic material, for example within 30% or 20% of the density of the polymer concerned.

It is apparent that in the case of the specific independent aspect described above, similar preferred embodiments to the third variant are possible, and therefore whether semi-crystalline or crystalline polymers are applied. The preferred embodiment is a decorative panel comprising a substrate and a top layer provided thereon, wherein the substrate comprises at least a filled synthetic material, wherein the filled synthetic material consists of at least a polymer, preferably thermoplastic, and a filler material, characterized in that the filler material comprises, preferably consists of, at least a first part and a second part of filler material, wherein the first part is a filler material having a density of 300kg/m ³ or less, such as 120-180kg/m ³, and/or comprises a filler material selected from the group consisting of rice hulls, Cork, bamboo, sugar cane, foamed synthetic materials, porous inorganic materials, perlite, vermiculite, celecoxite and pumice, and wherein the second part is a filler material having a density of 1200kg/m ³ or more, for example a density of 1800-3000kg/m ³, and/or comprises a filler selected from the group consisting of chalk, talc, limestone, lime stone, CaCO ₃, sand, and SiO ₂. Preferably the density of such filler material is within 25% of the polymer density and preferably within 20% of the polymer density. As mentioned above, the first portion and the second portion preferably constitute all of the filler material available in the filled synthetic material. Preferably the amount of filler material available in the filled composite material is expressed by the weight ratio of filler to composite material in the range 50% to 250%, or preferably 80% to 200%. Preferably the amount of filler material available in the filled composite material is expressed by the weight ratio of filler to composite material in the range 50% to 250%, or preferably 80% to 200%. Preferably the density of the filled synthetic material is within 30% of the envisaged polymer density, or within 20%. Preferably the second, high density portion of the filler material is present in the filled composite material in a higher weight percentage than the first portion, and preferably the second portion of the filler material is present in the filled composite material in a lower volume percentage than the first portion. Preferably the weight percent difference between the second portion and the first portion is at least 20wt% or at least 25wt%. Preferably the volume percent difference between the second portion and the first portion is at least 5vol%, or at least 10vol%.

Preferably, in the case of filled synthetic materials, the polymer and/or the filler material, whether or not conforming to the first, second or third variants, is provided with a coupling agent and/or maleic anhydride and/or a silane, such as an aminosilane. The use of maleic anhydride, silane or coupling agents enhances the incorporation of the filler material into the polymer.

It should be noted that alternatives to the fillers listed in the first to third variants include wollastonite, mica and thermo-mechanical pulp fibers.

In addition to the filler material, the substrate or the filled synthetic material (as the case may be) may also contain additives, such as one or more elastomers. Preferably, from 15 to 200phr (parts per hundred parts by weight of resin, i.e. fraction of semi-crystalline or crystalline polymer) of elastomer is used. The use of an elastomer allows the desired flexibility to be provided for the panel. Preferably the substrate has a flexural modulus of 550MPa or less, even more preferably 275MPa or less. As the elastomer, styrene-ethylene/butylene-styrene triblock copolymer (SEBS) may be used. Such elastomers are particularly effective where the semi-crystalline polymer is a propylene-ethylene random copolymer (PP-R).

Preferably in the substrate or in the filled synthetic material (as the case may be), the semi-crystalline or crystalline polymer is a semi-crystalline or crystalline homopolymer such as polypropylene or a mixture of polyethylene and semi-crystalline or crystalline heteropolymer. Preferably the heteropolymer is constructed from at least the monomers of the homopolymer. Preferably the heteropolymer is built up from monomers of the homopolymer by at least 30wt% or at least 50wt%. For example, in the case where the homopolymer is polypropylene, and correspondingly polyethylene, the heteropolymer may be constructed at least from propylene, and correspondingly ethylene, for example as in the case of a heteropolymer comprising ethylene and propylene, such as a propylene-ethylene random copolymer (PP-R). In a specific embodiment, the semi-crystalline or crystalline polymer is a mixture of a polypropylene homopolymer and an ethylene-propylene heteropolymer containing at least 50% ethylene, such as an ethylene-propylene-diene copolymer. In the mixture of homopolymer and heteropolymer of the present preferred embodiment, the homopolymer preferably constitutes 25 to 45mol%, even more preferably 30 to 40mol%.

According to a specific embodiment, the semi-crystalline polymer is foamed. Preferably, the foaming results in a weight loss of 10% or more. Preferably the foam is a closed cell foam, i.e. a foam in which the cells are predominantly closed cells. As foaming agent, for example, citric acid and/or sodium bicarbonate can be used. The ideal semi-crystalline polymer for foaming is polypropylene/polypropylene grafted glycidyl methacrylate/thermoplastic polyester elastomer (PP/PP-g-GMA/TPEE).

According to a most preferred embodiment of the first independent aspect of the invention, the substrate is a filled synthetic material comprising

-30-65 Vol% of semi-crystalline polymer;

-preferably 3vol% or more of elastomer;

-30vol% to 65vol% or more of filler material, and

-5Vol% or less of additives other than the elastomer and the filler material.

For semi-crystalline polymers, preference is given to using homopolymers and/or heteropolymers of ethylene and/or propylene. For example, the semi-crystalline polymer may be substantially a mixture of polypropylene and an ethylene-propylene copolymer or an ethylene-propylene-diene copolymer, or substantially a mixture of polyethylene and an ethylene-acrylic acid copolymer or an ethylene-propylene-diene copolymer, or substantially a mixture of polypropylene and COC or COP. The filler material may be selected according to the first, second or third variants described above.

The object is the same as the first independent aspect, according to a second independent aspect the invention is a method for manufacturing a decorative panel, wherein the panel comprises a substrate and a top layer provided thereon, wherein the substrate comprises at least a semi-crystalline polymer or a polymer selected from the list consisting of Polyacetal (POM), polyphenylene sulphide (PPS), polyamide (such as PA6 and PA 66), polyethylene terephthalate (PET), glycol modified polyethylene terephthalate (PETG), polycyclohexane dimethyl terephthalate (PCT), glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalic acid (PCTA), polyethylene (PE), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT) and polypropylene (PP), wherein the method comprises the step that the substrate is at least partly provided by an extrusion operation, in which the polymer is extruded through a die, preferably characterized in that the method further comprises one or a combination of two or more of the following steps.

According to a first possible step, the method comprises a step of cooling the extruded semi-crystalline polymer, for example in a bath, preferably a water bath. The water in the bath may be maintained at a temperature above the glass transition temperature of the polymer, but preferably below the melting temperature of the corresponding polymer. Preferably, the water is maintained at a temperature of 25-60 ℃. The crystallinity and/or orientation obtained in the frozen polymer is allowed to cool by a water bath. Preferably the cooling step is carried out upstream of any embossing operation providing structure to the top layer of the trim panel. In this case, the embossing can be performed more precisely, for example corresponding to the decor contained in the top layer. According to a variant or in combination with the bath, the extruded semi-crystalline polymer may be cooled using a nozzle or a curtain of liquid, preferably with water and/or a gas such as cooling air.

According to a second possible step, the method comprises the step of actively drawing said extruded semi-crystalline polymer from said die. By actively drawing the semi-crystalline polymer, such as polypropylene, potentially an ethylene-polypropylene copolymer as described above, a more defined orientation of the polymer in the extrusion direction may be obtained. The active draw may be obtained by pulling the extruded material in the nip of a pair of driven rolls or by a driven belt.

According to a third possible step, the method comprises the step of adhering a polymeric film (preferably a uniaxially or biaxially oriented polymeric film) to said extruded semi-crystalline polymer. The adhesion is preferably, for example, thermal lamination by one or more rollers. An adhesive oriented film, such as an oriented polypropylene film, can stabilize the trim panel. Preferably such films are applied to both sides of the extruded polymeric material. Alternatively, instead of adhering a polymer film, a layer, such as a polypropylene layer, may be cast directly or indirectly on the substrate comprising the extruded polymeric material. More generally, at least one polymeric film or layer, whether oriented, thermally laminated or cast on one or both sides of the extruded polymeric material is preferred. In case such a layer or film is provided on both flat sides, a trim panel with a more stable, balanced, sandwich structure can be obtained. If this third possible step is combined with the first possible step described above, the step of adhering the film is preferably carried out downstream of the cooling, for example downstream of the bath. In this case, the base material is more stable and can adhere to the film more accurately. According to a variant, the step of adhering the film occurs upstream of the cooling, for example upstream of the bath or upstream of the contact with a cooling roller. In the latter case, the useful heat of the extruded polymeric material may be used to adhere the film, while the cooling may freeze the crystallinity of the base material and/or top layer. It will be apparent that the film or layer may be one on which decorative printing is or will be provided. Alternatively, the film or layer may be or form part of a transparent or translucent wear layer applied to the decorative print or decorative printed foil.

According to a fourth possible step, the method comprises a step of heat-treating the surface of the extruded semi-crystalline polymer, preferably by means of rolls and/or plates, which are preferably cooled. According to a variant, or in combination therewith, one or more rolls and/or plates may be heated. Preferably the rolls and/or plates are in direct contact with the surface of the extruded semi-crystalline polymer. The step of heat treating the extruded material is such that the crystallinity and/or orientation is set to a desired level. The heat treatment step may also be used to anneal the potentially induced stresses. Preferably the heat treatment step occurs between the die and a possible subsequent lamination operation, wherein, for example, the top layer or part thereof is laminated on the extruded semi-crystalline material and/or between the lamination operation and a possible embossing operation providing structure to the decorative panel top layer.

According to a fifth possible step, the method comprises a step of cooling and subsequent heat treatment of the extruded semi-crystalline polymer, whether forced or not, and vice versa. The combination of cooling and subsequent heating may result in freezing of crystallinity and/or orientation, while subsequent heating may result in induced stress annealing and a shrinkage effect. Such heat treatment may avoid excessive shrinkage after manufacture and/or installation. It is obvious that the heating and/or cooling can be achieved in many different ways, as by using a water bath or a nozzle, as described in the first possible step, or by using rollers and/or plates, as described in the fourth possible step.

According to a sixth possible step, the method comprises a step of controlling the crystallinity of said extruded semi-crystalline polymer. The crystallinity is preferably controlled by measuring the crystallinity of the extruded semi-crystalline material on-line or off-line and varying at least one of the extrusion speed, the extrusion temperature, the temperature of the heat or cold treatment (e.g. the water temperature in the bath of the first possible step) and/or the temperature of the rolls and/or the plates (as described in connection with the fourth possible step). For on-line measurement of crystallinity, optical methods may be used. For example, the extruded semi-crystalline material may be irradiated with a light beam, scattered light collected, the collected scattered light converted to a raman spectrum, and crystallinity determined using the raman spectrum. For example, the method described in WO 1999/027350 may be used. The result may be used, for example, to automatically adjust the extrusion speed, extrusion temperature and/or the temperature of the heat treatment or cold treatment in a feedback loop.

According to a seventh possible step, the method comprises the step of dividing said extruded semi-crystalline polymer into panels having dimensions corresponding or substantially corresponding to the dimensions of the final obtained panels. For example, the panels may be rectangular and oblong. According to a specific embodiment, the longitudinal direction of the panel is formed perpendicular to the extrusion direction. In this case, the potential shrinkage or other dimensional instability caused by the orientation of the semi-crystalline polymer in the extrusion direction is in the transverse direction of the panel and can therefore be limited to absolute dimensions.

According to an eighth possible step, the method comprises the step of drying the polymer to be extruded and/or of drying the filler material to be incorporated in said polymer before mixing said polymer and said filler material. These drying steps are particularly important when the polymer is PET, PETG, PCT, PCTG or PCTA. These polymers are prone to hydrolysis.

According to a ninth possible step, the method comprises, for example, the step of feeding a quantity of filler material directly into the extruder barrel via one or more inlets downstream of the main extruder inlet. Preferably the main filler amount (i.e. over 50%), all or almost all of the filler amount is added to the material to be extruded through the inlet or inlets downstream of the main extruder inlet. Thus, only a small portion of the filler material is added to the polymer or not at all prior to extrusion and/or through the main extruder inlet. At the inlet of the main extruder, the polymer (possibly with additives) may be added to the barrel in the form of granules, flakes or needles.

A deep vacuum, for example, a pressure below 5 mbar, even below 2 mbar, is preferably applied in the extruder used in the extrusion operation in order to remove any residual water or other contaminants in the extruder section. The low vacuum is particularly important when the polymer is PET, PETG, PCT, PCTG or PCTA.

Preferably, a parallel or conical co-rotating twin screw extruder is used in the extrusion operation. The use of single screw extruders or multiple screw rotary extruders is not precluded.

According to still other possible steps, the method comprises:

-a step of forming an outermost layer of the substrate, wherein the outermost layer comprises an elastomer, preferably the outermost layer is co-extruded with the polymer, for example through the same die;

-a step of applying an adhesive layer, a heat-seal additive, ethylene-vinyl acetate or ethylene-methyl acrylate to the outermost surface of the substrate, and/or

-A step of corona or plasma treatment of the outermost surface of the substrate.

It will be apparent that the method of the second aspect is preferably applied to the manufacture of a panel according to the first aspect of the invention and/or preferred embodiments thereof.

In general, it is noted that wherever crystallinity values are described herein, the crystallinity is preferably measured using Differential Scanning Calorimetry (DSC) and/or at a heating rate of 20 ℃ per minute according to ISO 11357-3:2018. Using DSC, the remaining enthalpy of crystallization in the sample to 100% crystallinity can be measured. The residual enthalpy was compared with the total crystallization enthalpy from an amorphous sample of the same polymer, to calculate the percentage of additional crystallization that occurred during DSC. It is apparent that the degree of semi-crystallization present in the sample before DSC onset can be expressed as 100% minus the percentage of additional crystallization obtained.

It is further apparent that where in the first and second aspects of the invention a semi-crystalline polymer is mentioned, the polymer may be or instead be a polymer selected from the list consisting of Polyacetal (POM), polyphenylene sulphide (PPS), polyamides such as PA6 and PA 66, polyethylene terephthalate (PET), polyethylene (PE), low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT) and polypropylene (PP). According to the invention, such polymers do not necessarily have to be semi-crystalline, but may for example be crystalline or substantially amorphous.

According to a most preferred embodiment, the polymer or semi-crystalline polymer is a mixture of polypropylene and an ethylene-propylene copolymer or an ethylene-propylene-diene copolymer, or a mixture of polypropylene and an amorphous polymer or copolymer (such as COC or COP).

According to the invention, the substrate may be a single layer or comprise a plurality of substrate layers, preferably an odd number of substrate layers. The substrate, whether single or multi-layered, preferably constitutes at least half the thickness and/or half the weight of the trim panel and/or is at least usable in a central location within the trim panel thickness.

The decorative panel of the present invention preferably has a total thickness of 2-8mm, and more preferably 3.2-5.5 mm. The substrate, whether multilayer or single layer, preferably has a thickness of 2-5 mm.

It is clear that in the context of the present invention any panel portion, denoted layer, e.g. a substrate layer, has significantly different properties than the adjacent layers. Such different properties may include, for example, different material compositions, different colors, different geometries.

As described in any of the aspects, the top layer may comprise a decoration, preferably a printed decoration. The top layer may also comprise a transparent or translucent layer applied to the top of the printed decor. According to a first possibility, the printed decoration is applied on a polymeric foil, such as a polypropylene foil or a polyethylene foil. In this case, the wear layer may also comprise a polypropylene foil or a polyethylene foil, and possibly a surface varnish layer, for example a UV and/or excimer (excimer) cured varnish layer, such as a polyurethane varnish layer. According to a second possibility, the printed decoration is applied by forming it on a semi-crystalline material, possibly with an intermediate layer of one or more primer layers and/or background layers. In this case, the abrasion resistant layer may be formed as a liquid applied UV and/or excimer cured varnish layer, for example an acrylic varnish layer. According to one embodiment, the top layer comprises one or more casting layers, for example polypropylene casting layers. Such a casting layer may form a primer and/or background layer for the print formed on the substrate and/or may form part of a transparent or translucent wear layer that prints the decorative top.

The decor of the top layer preferably comprises a wood pattern. In this case, the wood pattern preferably has a grain direction corresponding to the direction of one edge of the panel and/or the direction of the latent orientation direction of the polymer of the substrate. In the case of rectangular and oblong panels, it preferably corresponds to the direction of the longitudinal edges.

The trim panel of any of the above aspects may be provided with connecting members on at least two opposite edges, allowing two such panels at the respective edges to be connected to each other, wherein in the connected state a locking is obtained in a vertical direction perpendicular to the plane of the connecting panels and in a horizontal direction perpendicular to said edges in the plane of the connecting panels. Preferably, the connecting element is essentially formed as a tongue (tongue) and groove (groove) with a locking means. Such a connecting member is for example described in WO 97/47834. The connecting member and the locking means preferably have one or more of the following properties:

-the connecting member and the locking means are integrally formed with the material of the trim panel. Preferably forming a profile of at least 70% of the respective edges on the substrate comprising the semi-crystalline polymeric material and/or the filled synthetic material, as seen in a cross-section in a plane perpendicular to the edges;

the groove has a lower groove lip (groove lip) and an upper groove lip, wherein the lower groove lip preferably extends beyond the upper groove lip. Preferably the locking means comprises a protrusion formed on the upper side of the lower tongue lip and a recess (excavation) at the bottom of the tongue;

-the underside of the upper tongue-and-groove lip and/or the upper side of the lower tongue-and-groove lip is formed entirely in the substrate comprising the semi-crystalline polymeric material and/or the filled synthetic material. The underside of the upper tongue-and-groove lip and/or the upper side of the lower tongue-and-groove lip is preferably formed entirely of the semi-crystalline material and/or the filled synthetic material;

-the substrate is an extruded semi-crystalline polymer, wherein the horizontal direction coincides with the extrusion direction, wherein the panels are rectangular and oblong and the connecting means are preferably usable at the pair of longitudinal edges. Alternatively, the connecting members may be used at one pair of short edges and/or at both pairs of edges.

In general, the inventors noted that a decorative panel having a top layer applied to a substrate comprising a semi-crystalline or crystalline polymer and/or a polymer selected from the list consisting of polyacetal (also known as Polyoxymethylene (POM)), polyphenylene sulfide (PPS), polyamides (such as PA6 and PA 66), polyethylene terephthalate (PET), glycol modified PET (PETG), polycyclohexane dimethyl terephthalate (PCT), glycol modified polycyclohexane dimethyl terephthalate (PCTG), polycyclohexane dimethylene terephthalate (PCTA), polyethylene (PE), low Density Polyethylene (LDPE) (e.g., linear Low Density Polyethylene (LLDPE)), high Density Polyethylene (HDPE), polybutylene terephthalate (PBT), polylactic acid (PLA), polyetheretherketone (PEEK) and polypropylene (PP) may be prone to top layer delamination problems. The inventors believe that this may be due to the effect of tension differences in the top layer and the substrate as they cool down after thermal lamination.

According to a second possible property, i.e. preferably measured using Differential Scanning Calorimetry (DSC) according to ISO 11357-3:2018, the crystallinity of the polymer is higher than 35%, preferably higher than 50%, such decorative panels may in particular show differential tension. The crystallinity may be, for example, about 60%. Cooling of polymers with such high crystallinity can result in higher tension differences between the layers (e.g., between the substrate and the decorative top layer) that can partially fail the adhesion.

Regardless of its crystallinity, the surface energy of the polymer, e.g., the surface energy of polypropylene (PP), may play an important role. For example, the surface energy of polypropylene is too low to make good adhesion difficult to achieve.

Various measures can be taken to increase the lamination strength of the top layer to the substrate. Preferably, one or more of the following possible measures are taken.

According to a first possible measure, an elastomer is used as additive in the polymer, for example, 0.1 to 7.5phr. For example, thermoplastic Polyolefin (TPO) is used as the elastomer. Practical examples of elastomers that can be used according to the first possible measure include:

Thermoplastic polyolefin obtained by the Cataloy process or by any multistage gas phase polymerization process, for example homo-or heteropoly polypropylene;

Block copolymers such as polypropylene;

-a styrene block copolymer;

-a polymer or copolymer comprising or consisting of ethylene-propylene-diene-monomer (EPDM), styrene-ethylene-butadiene-styrene (SEBS), poly (styrene-butadiene-ethylene) (SBS), polyether block amide (PEBA), thermoplastic Polyurethane (TPU), styrene-ethylene-propylene-styrene (SEPS), styrene-ethylene-propylene-styrene (SEEPS), acrylonitrile-ethylene-styrene (AES) or Polybutadiene (PB).

According to a second possible measure, the substrate or one or both outermost layers of the extruded sheet comprised in the substrate comprise or consist of an elastomer. The elastomers mentioned in the first measure are preferably used. Such an outermost layer may be coextruded with the remainder of the extruded sheet contained in or forming the substrate. Preferably, this outermost layer is formed to less than 10% of the thickness of the substrate. This second possible measure would produce similar results from the point of view of adhesion to the top layer, but with less impact on the mechanical properties (such as flexibility) of the substrate or extruded sheet as a whole. When such an outermost layer is applied to the surface of the substrate opposite the top layer, for example, a higher adhesion to the underground or to the sound-insulating layer applied in production during installation can be obtained.

According to the first and second possible measures, the temperature required to obtain good adhesion during thermal lamination of the top layer can be reduced. This is also advantageous in view of the fact that the lamination of the embossed top layer is already provided before the thermal lamination. For example, such a top layer may comprise a printed foil and a transparent wear layer comprising polypropylene cast thereon and subjected to an embossing treatment. During thermal lamination, the risk that such embossing will reduce or even disappear is minimized.

According to a third possible measure, the substrate or one or both outermost layers of the extruded sheet contained in the substrate comprise or consist of an adhesive layer (tie layer) or a heat-seal additive, for example a maleic anhydride grafted polypropylene or polyethylene based adhesive, a polyethylene based adhesive. Heat seal additives are well known per se in the food packaging industry to improve the sealing of bags. The inventors have found that these sealing additives can be used to improve the adhesion between the top layer of the inventive trim panel and the substrate.

According to a fourth possible measure, the substrate or one or both outermost layers of the extruded sheet comprised in the substrate may comprise or consist of ethylene-vinyl acetate or ethylene-methyl acrylate. Ethylene vinyl acetate and/or ethylene methyl acrylate are particularly effective for improving the lamination strength on a substrate comprising polypropylene as the polymer (e.g., polypropylene having a crystallinity of 50% or more).

According to a fifth possible measure, the surface of one or both outermost layers of the substrate may be corona or plasma treated. Such a treatment is preferably employed when the corresponding surfaces are above room temperature, for example when these surfaces still have an elevated temperature due to the extrusion process. Preferably no forced cooling step is applied to the extruded sheet between extrusion and corona or plasma treatment and/or corona or plasma treatment is initiated or carried out within the first five meters or the first two meters from the die (measured along the trajectory of the extruded sheet).

According to a sixth possible measure, the cooling operation is performed on the top layer as soon as possible after the hot lamination, for example starting within the first two meters from the die (measured along the trajectory of the extruded sheet). The cooling operation may be performed by a cooling roll contacting the top layer. This cooling operation may freeze the crystallinity of the substrate and/or the top layer. In this case, the tension difference that causes the sticking problem can be kept to a minimum.

It is apparent that the extruded sheets mentioned above are preferably obtained from an extrusion operation wherein the polymer is extruded through a die preferably having a slot opening. It is further apparent that the resulting sheet material has dimensions that may be greater than the desired dimensions of the final trim panel, and therefore, the sheet material may need to be formed into a plurality of panels having the final dimensions of the trim panel, with these panels being subsequently further processed and finished to form the trim panel of the present invention.

It is apparent that the above possible measures against delamination and increasing adhesion lead to corresponding preferred embodiments of the first and/or second aspect of the invention.

Drawings

For a better demonstration of the features of the invention, some preferred embodiments are described hereinafter, by way of example without any limiting features, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a floor panel having features of the present invention;

FIG. 2 shows a cross-section of the line II-II shown in FIG. 1 on a larger scale;

fig. 3 shows a connection state of the connection device shown in fig. 2;

Fig. 4-6 show the cross-section of the IV-IV line shown in fig. 1 on a larger scale, but in a variant;

Fig. 7 and 8 show variants in a view similar to fig. 3;

FIG. 9 shows a variation in a view similar to FIG. 2;

FIG. 10 illustrates some steps in a method of manufacturing a trim panel according to the present invention;

fig. 11-13 show variations in the view of the area indicated by F11 in fig. 10.

Detailed Description

Fig. 1 shows a rectangular floor panel 1. In this case, the floor panel 1 is rectangular and oblong.

Figure 2 clearly shows that the floor panel 1 comprises a substrate 2 and a decorative top layer 3 arranged thereon.

The substrate 2 comprises a semi-crystalline polymer 4, in this case a filled ethylene-propylene copolymer, and is provided on at least two opposite edges 5-6-7-8, in this case a pair of opposite long edges 5-6 and a pair of opposite short edges 7-8, with mechanical connection means 9.

Figure 2 shows clearly that the connecting means 9 on the opposite long edges 5-6 are basically realized as a tongue 10 and a groove 11 with an upper tongue lip 12 and a lower tongue lip 13. In this case, the lower tenon lip 13 extends in the horizontal direction beyond the distal end 14 of the upper tenon lip 12. The connection means 9 shown at least allow connection by a rotational movement W along the respective edge 5-6.

Fig. 3 shows that in the connected state, locking is obtained in a horizontal direction H1 perpendicular to the connecting edges 5-6 and in the plane of the panel 1 and in a vertical direction V1 perpendicular to the plane of the connected panel 1. The connection means 9 consist of a milled profile (milled profile) at least 70% of the periphery of which is arranged in the substrate 2 and in this case in the filled semi-crystalline polymer 4. In this case, the connecting means 9 are virtually completely disposed in the filled semi-crystalline polymer 4 of the substrate 2, but the portions 15 of their periphery are formed on the decorative top layer 3.

Fig. 3 shows that at least one pair of horizontal active locking surfaces 16-17 of the connection means 9 is realized in the semi-crystalline polymeric material 4 of the substrate 2. Here this involves a first pair of locking surfaces 16-17 formed on the protruding locking portion 18 of the lower tongue lip 13 and a locking groove 19 cooperating therewith on the underside of the tongue 10. In this example, a second pair of horizontal active locking surfaces 20-21 is formed on the decorative top layer 3, or on the above-mentioned portion 15 of the outer periphery of the connecting means 9. Several pairs of vertical active locking surfaces 22-23-25-26 are formed of the filled semi-crystalline polymer 4 of the substrate 2. Here this involves at least a first pair of vertical active locking surfaces 22-23 on the upper side of the tongue 10 and the lower side of the upper tongue lip 12 of the groove 11, and at least a second pair of vertical active locking surfaces 25-26 on the lower side of the tongue 10 and the upper side of the lower tongue lip 13 in the groove 11. In the example of fig. 3, the second pair of vertical active locking surfaces 25-26 are formed such that they extend at least horizontally at a position vertically below the above-mentioned upper tongue lip 12. In this case, a third pair of vertical active locking surfaces 27-28 are also formed adjacent to the first horizontal active locking surfaces 16-17 described above.

Fig. 4 clearly shows that at least one layer, and in this case even a plurality of reinforcement layers 29-30, may be applied in the substrate 2. In this example, the first reinforcement layer 30 extends uninterrupted in the lower tenon lip 13 and the second reinforcement layer 29 extends uninterrupted in the upper tenon lip 12. Thus, the first and second reinforcement layers 29-30 are positioned off-center with respect to the thickness T1 of the substrate 2. On the side of the reinforcement layers 29-30 facing away from the centre of the substrate 2, in this example, the reinforcement layers are each time flanked by an additional substrate layer 31 of filled semi-crystalline polymer. In this example, these additional substrate layers 31 exhibit a different composition than the central substrate layer 32 of the substrate 2, e.g., they contain no or less filler than the central substrate layer 32. It should be noted that the example of fig. 4 shows a fifth possible characteristic mentioned in the summary of the invention, wherein said additional substrate layer 31 has an equal thickness and is positioned with one of its main surfaces equidistant from the centre line C of the substrate 2. The additional substrate layer 31 is at least remote from the central substrate layer 32.

It is evident that the substrate 2, or at least its central substrate layer 32, is preferably positioned such that it is at least at the center of the substrate 2, i.e. on the center line C. In this case, the thickness T2 of the central substrate layer 32, i.e. the layer between the two reinforcing layers 29-30, is equal to more than 40% of the substrate thickness T1.

The decorative top layer 3 described above comprises a printed pattern 33 and represents a single wood board. The printed pattern 33 is provided on a thermoplastic foil 34, i.e. in this case a biaxially oriented polypropylene foil. The floor panel 1 further comprises a translucent or transparent wear layer 35 arranged above the above mentioned decorative or printed pattern 33.

It should be noted that according to an embodiment not shown, the floor panel 1 according to the invention may show additional layers on the underside of the substrate 2. Here, this preferably involves a foam layer, for example a crosslinked (cross-linked) or crosslinked (cross-linked) polyethylene (XPE) foam layer, which is fixed to the underside of the substrate 2 by means of glue, for example in particular to the substrate layer 31 flanking the reinforcement layer 30. In this case, this relates to a soft foam.

Furthermore, it should be noted that in the connected state of fig. 3, a tensile force can be obtained between the respective floor panels 1, more specifically at the location of the second pair of horizontal active locking surfaces 20-21, i.e. between the respective decorative top layers 3 on the upper edges of the connected floor panels 1. The dashed line 36 in fig. 3 indicates that such tension can be obtained, for example, that the lower tongue lip 13 in the connected state is deflected by a spring (spring-deflected) and pushes the tongue 10 in the connected condition. Such pretension is known from, for example, WO 97/47834.

According to a variant, not shown in fig. 3, in the connected state, there may be a so-called play, instead of pretension. In this case, there may be some space between the first pair of horizontal active locking surfaces 16-17 in the connected state, while the second pair of horizontal active locking surfaces is in contact with the tongue 10 at a position above the vertical active contact surfaces 22-23 between the upper side of the tongue 10 and the lower side of the upper tongue lip 12 of the groove 11. Such a space preferably extends over a horizontal distance of less than 0.2mm or less.

In the example of fig. 1-3, the same connecting means 9 are applied at the opposite short edges 7-8 on the floor panel 1 as at the opposite long edges 5-6.

In addition to the optional reinforcement layer 29-30 and the optional additional substrate layer 31, fig. 4 gives an example of a decorative panel according to the invention, wherein the short edges 7-8 are provided with connecting means 9 having male parts 37 and female parts 38, which allow two such floor panels 1 to be connected at the respective short edges 7-8 by a downward movement M of the male parts 37 in the female parts 38, wherein in the connected state a locking in the horizontal direction H1 as well as in the vertical direction V1 is achieved. For example, according to fig. 2 and 3, a combination of a rotatable contour on the long edge 5-6 and a downwardly connectable contour on the short edge 7-8, for example according to any of fig. 4-6, results in the formation of a floor panel 1, which floor panel 1 can be connected by a so-called fold-down movement. Here, the long edges 5-6 are provided with each other by a rotational movement W, wherein by this rotational movement W at the short edges 7-8 a downward movement M is generated, which provides the male part 37 present in the female part 38.

The example of such a downwardly connectable profile shown here is made in one piece with the base material 2 of the floor panel 1 and comprises a mating catch 39 and undercut 40 for achieving locking, and a hook-shaped element 41 on the lower tongue lip 13, in which case the hook-shaped element 41 also shows an undercut 42. The undercut 42 on the hook-shaped element 41 is made at an angle A1 of 1 deg. to 10 deg. (preferably about 5 deg.) to the vertical. The locking groove 19, which cooperates with the hook elements 41 described above, is located entirely under the reinforcement layer 29 at the upper surface.

In this case, the above-mentioned mating hooks 39 and undercut 40 comprise perpendicular active contact surfaces 22-23 that mate in the connected state, this mating being achieved in the filled semi-crystalline polymer 4 of the substrate 2. The horizontal and vertical active contact surfaces 16-17 of the hook members 41 are also fully realized in the filled semi-crystalline polymer 4 of the substrate 2.

The upper surface of the lower tongue lip 13 is entirely composed of the filled semi-crystalline polymer 4 of the substrate 2. In the connected state, the edge profile also shows vertical active contact surfaces 25-26 formed on the upper surface. There is a space 43 between these vertical active contact surfaces 25-26 and the horizontal active contact surfaces 16-17. The uppermost reinforcing layer 29 extends integrally over the above-mentioned locking groove 19 at the underside of the male coupling part 37.

On the underside of the lower tongue lip 13, a recess 44 is formed, which extends at least partially below the space 43. Which provides a smoother connection even if there is an overlap 45 in the contours of the male 37 and female 18 connecting members at the location of the horizontal active locking surfaces 16-17. The lowermost reinforcing layer 30 is removed at the position of the recess 44. This need not necessarily be the case. According to an embodiment, not shown, the lowermost reinforcement layer 30 may extend integrally above said recess 44.

Fig. 5 shows a profile variant which can be connected to one another by a downward movement M, wherein the catch 39 is located at the distal end 46 of the lower tongue lip 13 of the female part 38, while the undercut 40 is provided in the male part 38. Here too, the upper surface of the lower tongue 13 is formed entirely of the filled semi-crystalline polymer 4 of the substrate 2, and in the bonded state the edge profile shows the vertical active contact surfaces 25-26 formed on this upper surface. There is a space 43 between these vertical and horizontal active contact surfaces 16-17. The lowermost reinforcement layer 30 extends integrally in the lower dovetail lip 13, while the uppermost reinforcement layer 29 extends integrally over the above-mentioned locking dovetail groove 19 on the underside of the male coupling component 37.

In the example of fig. 5, the hook-shaped part 41 also has an undercut 42, wherein the undercut 42 is realized at an angle A1 of 1 ° to 10 ° (preferably about 5 °) from the vertical. It is obvious that in fig. 4 and 5 such undercut 42 at the position of the horizontal active contact surfaces 16-17 on the hook-shaped element 41 is not necessary, but that contact surfaces with a vertical or less inclination than vertical, for example, with a corresponding contact surface inclined at an angle of 45 deg. to 90 deg. to the horizontal, may also be used.

Fig. 6 shows a variant of the profile that can be connected downwards, wherein the catch 39 is formed by a separate insert 46, in which case the insert 46 is arranged in the male part 37. Such a separate insert 46 is preferably formed of a thermoplastic material, for example at least PP, PVC or ABS (acrylonitrile butadiene styrene), and in the connected state preferably shows (for example here) a vertical active contact surface 22 with the filled semi-crystalline polymer 4 of the female part 38. In this way, an accurate vertical positioning of the male part 37 in the female part 38 can be obtained. In this example, the above-mentioned independent insert 46 is located in a seat 47 having walls formed entirely of the filled semi-crystalline polymer 4 of the substrate 2.

It is apparent that in the example of fig. 4 to 6, the hook-shaped portion 41, the locking groove 19 on the underside of the male part 37 with which it cooperates, extends up into the upper half of the base material 2 each time so as to extend above the centre line C.

Fig. 7 shows a further variant in which the connecting means 9, for example, the connecting means 9 of the opposite long edges 5-6, show some preferred features, each of which, alone or in any combination, provides an edge profile that is ideally suited for application to a floor panel 1 of a substrate 2 employing a filled semi-crystalline polymer 4, such as a filled ethylene-propylene copolymer. This is related to the following features:

The vertical active locking surface 25-26 between the underside of the tongue 10 and the upper side of the lower tongue lip 13 is in this case substantially even entirely on the protrusion 48 of the lower tongue lip 13, i.e. on the portion of the lower tongue lip 13 extending beyond the distal end of the upper tongue lip 12. Preferably, in the connected state, a space 49 is located between the underside of the tongue 10 and the upper side of the lower tongue lip 13, wherein this space 49, e.g. here, extends horizontally below the tongue 10, at least from the tip 50 of the tongue 10 up to beyond the distal end of the upper tongue lip 12. In this way, the risk of breaking the tongue 10 is minimized when turning the tongue 10 into the groove 11, while still obtaining a sufficient vertical locking, and/or

The projection of the vertical active contact surface 25-26 between the underside of the tongue 10 and the upper side of the lower tongue lip 13 in the horizontal plane shows a length L1, which length L1 is at least 15%, and preferably at least 20% or 25%, of the length L2 of the protrusion 48 of the lower tongue lip 13, and/or

The length L2 of the projection 48 of the lower tongue 13 is at least 80% of the thickness T1 of the substrate layer comprising the filled semi-crystalline polymer 4, and preferably less than 130% of its thickness T1, and/or

The minimum width B1 of the upstanding portion 18 of the lower tongue 13 at the location of the horizontal active locking surface 16-17 is at least 15% of the thickness T1 of the substrate layer comprising the filled semi-crystalline polymer 4, and more preferably at least 20% of the thickness T1 of the substrate layer comprising the filled semi-crystalline polymer 5.

Fig. 8 shows a further variant in which the connecting means 9, for example of the opposite long edges 5-6, show some preferred features, each of which, alone or in any combination, gives an edge profile that is well suited for application to floor panels 1 with a substrate 2 of semi-crystalline polymer 4 (whether filled or not, such as an ethylene-propylene copolymer). This relates in particular to the features mentioned in connection with fig. 7, as well as the following features, which, however, do not need to be applied in combination with the features in fig. 7:

The lower tongue 13 shows a point 51 or area where the remaining thickness D1 of the lower tongue 13 is smallest, wherein the floor panel 1 comprises a reinforcement layer 30 extending in the respective lower tongue 13, and wherein said reinforcement layer 30 is off-centre from said remaining thickness D1 at the location of said point 51 or area, preferably closer to the upper side than to the lower side of the lower tongue 13, as indicated here with arrow E1. In this way, a possible bending of the lower tongue 13 is very significantly influenced, and/or

The upper tongue lip 12 shows a point or area 52 at the position perpendicular to the active locking surface 22-23, wherein the remaining thickness D2 of the upper tongue lip 12 is minimal, wherein the floor panel 1 comprises a reinforcement layer 29 extending in the respective upper tongue lip 12, and wherein said reinforcement layer 29 is off-centre from said remaining thickness D2 at the position of said point or area 53, preferably closer to the lower side than to the upper side of the upper tongue lip 12, as indicated here with arrow E2. In this way, a very significant effect is exerted on a possible bending of the upper tongue lip 12.

It should be noted that the exemplary connecting means 9 illustrated by the figures may be used for any pair of opposite edges 5-6-7-8 in any decorative panel 1 having the features of the specific independent aspects mentioned in the first aspect and/or in the summary of the invention, and/or any pair of opposite edges 5-6-7-8 in any decorative panel 1 obtained by the method according to the second aspect of the invention and/or by the preferred embodiments of these aspects.

Fig. 9 shows an exemplary floor panel 1 with a substrate 2 employing an integrated reinforcing layer 29A. In this case a woven glass fibre reinforced layer 29A. The woven glass fiber reinforcement layer 29A has a network structure of glass fibers 53 extending in at least two intersecting directions. In the plane of fig. 9, a cross section of glass fibers 53 extending in the longitudinal direction of the floor panel 1 is shown, while in dashed lines 54 glass fibers extending in the transverse direction of the floor panel 1 are shown. The semi-crystalline or crystalline polymer of the substrate 2 continues through the openings 55 of the stiffening layer 29. In this case, the semi-crystalline polymer 4 is continuous through the openings 55 of the network or staggered structure. In this example, the reinforcing layer 29A is located at the center in the base material 2, i.e., at the middle, approximately at the middle, or substantially at the middle of the thickness T1 of the base material 2. Preferably, the two substrate portions 2A-2B on either side of the stiffening layer 29A have the same or similar composition.

Fig. 10 shows a method of manufacturing a decorative floor panel 1 with a substrate 2 and a top layer 3 provided thereon. The substrate 2 comprises a semi-crystalline polymer 4. The substrate 2 is provided by an extrusion operation S1 in which the semi-crystalline polymer 4 is extruded through a die 56. The illustrated method further comprises a step S2 of actively drawing the extruded semi-crystalline polymer 4 from the die 56. In this case, the extruded semicrystalline polymer 4 is drawn in the nip 57 of a pair of driven rollers 58, which driven rollers 58 may also thickness calibrate and/or cool the extruded semicrystalline polymer 4.

Fig. 10 further shows that a step S3 of cooling the extruded semi-crystalline polymer 4 may be included in the method of the invention. Fig. 10 shows that this can be accomplished by a cooling plate 59 preferably in contact with one or more surfaces of the extruded semi-crystalline polymer 4. In this example, the heat treatment occurs downstream of die 56 and upstream of the subsequent lamination operation S4 and embossing operation S5.

Fig. 11 shows a variant in which in step S3 the extruded semi-crystalline polymer 4 is cooled by spraying water on one or more surfaces of the extruded semi-crystalline polymer 4 using a nozzle 60.

Fig. 12 shows a variant in which in step S3 the extruded semi-crystalline polymer 4 is cooled in a water bath 61, in which the temperature of the water is kept above the glass transition temperature of the semi-crystalline polymer 5.

Fig. 13 shows a variant in which in step S3 the extruded semi-crystalline polymer 4 is heat treated using a further cooled and/or heated roller 62. This additional roller 62 may help to further calibrate the thickness T1 of the extruded semi-crystalline polymer 4.

It should be noted that the driven roller 58 may be heated or cooled to assist or participate in the heat treatment of step S3.

In the lamination step S4 of fig. 10, a biaxially oriented polymer film 63 is applied onto the extruded semi-crystalline polymer 4 by a thermal lamination operation using a roller 64 upstream of the heat treatment step S3. In this case, the polymer film 63 is the decorative layer 3 having the printed pattern 33. In the lamination step S4, the film 63A is also thermally laminated at the bottom of the extruded semi-crystalline polymer 4. Preferably, the film 63A is oriented the same as the biaxially oriented polymer film 63 applied on top of the extruded semi-crystalline polymer 4.

As shown, an abrasion resistant layer 35 (e.g., in the form of a transparent biaxially oriented polymer film 63B) may also be applied on top of the printed pattern 33.

Preferably, at least one of the orientation axes of polymer films 63 and 63A is equal or substantially equal. It is preferred that the orientation axes of the polymer films 63 and 63A coincide with the orientation direction and/or extrusion direction F of the semi-crystalline polymer 4.

Fig. 10 also shows that the method comprises a step S6 of controlling the crystallization amount of the extruded semi-crystalline polymer 4. In this example, the crystallinity of the semi-crystalline polymer 4 is measured optically by illuminating the extruded semi-crystalline polymer 4 with a light beam 65, collecting scattered light, and converting the collected light into raman spectra. Then, as indicated by a broken line 66, information on the crystallinity may be used to change at least one of the extrusion speed, the extrusion temperature, and the temperature of the heat treatment step S3.

Fig. 10 also shows that the method comprises a step S7 of dividing the extruded semi-crystalline polymer 4 and the applied film 63-63A-63B into panels 1 having the general dimensions of the floor panel 1 to be finally obtained. The singulation may be performed by a saw and/or punch and/or knife 67.

The invention is not limited to the preferred embodiments described herein above, but such panels and methods may be implemented according to several variants without departing from the scope of the invention.

Claims

1. A decorative panel comprising a substrate (2) and a top layer (3) arranged thereon, wherein the substrate (2) comprises at least a semi-crystalline polymer (4), characterized in that the decorative panel (1) exhibits one or a combination of two or more of the following properties:

- the property that the polymer has a crystallinity of less than 85% as measured using differential scanning calorimetry;

- the property that the polymer has a crystallinity higher than 35%, preferably higher than 50%;

- the property that the polymer is uniaxially oriented;

- the property that the top layer comprises a semi-crystalline polymer, wherein the crystallinity of the polymer comprised in the substrate (2) is lower than the crystallinity of the polymer comprised in the decorative top layer (3);

- the substrate (2) comprises a plurality of substrate layers, wherein at least two of the plurality of substrate layers comprise properties of a semi-crystalline polymer (4).

2. The decorative panel according to claim 1, characterized in that the semi-crystalline polymer (4) is selected from the list consisting of polyacetal (POM), polyamide (PA 6 and PA 66), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and polypropylene (PP).

3. The decorative panel according to claim 1, characterized in that the substrate (2) comprises a filled synthetic material, wherein the filled synthetic material is formed by at least the semi-crystalline polymer (2) and a filling material.

4. The decorative panel according to claim 3, characterized in that the filling material comprises a material selected from the list consisting of rice husk, cork, bamboo, sugar cane, foamed synthetic material, porous inorganic material, perlite, vermiculite, senoite and pumice.

5. The decorative panel according to claim 3 or 4, characterized in that the filling material comprises a material selected from the list consisting of chalk, talc, limestone, _CaCO3 , sand and _SiO2 .

6. Decorative panel according to any of the preceding claims, characterised in that the semi-crystalline polymer (4) is foamed.

7. Decorative panel according to any of the preceding claims, characterized in that the semi-crystalline polymer is a mixture of polypropylene and ethylene-propylene copolymer or ethylene-propylene-diene copolymer and/or the semi-crystalline polymer is a mixture of polypropylene with an amorphous polymer or copolymer, such as with a cycloolefin polymer or copolymer.

8. A decorative panel comprising a substrate (2) and a top layer (3) arranged thereon, wherein the substrate (2) comprises at least a filled synthetic material, wherein the filled synthetic material is formed at least from a preferably thermoplastic polymer and a filling material, characterised in that the filling material comprises a filling material having a density of 300 kg/m ³ or less, for example 120-180 kg/m ³ , and/or a material selected from the list consisting of rice husks, cork, bamboo, sugar cane, foamed synthetic materials, porous inorganic materials, perlite, vermiculite, selenite and pumice.

9. A decorative panel according to claim 8, characterized in that all or at least 75 vol% of the filling material in the filled synthetic material is the filling material having a density of 300 kg/m ³ or less, such as 120-180 kg/m ³ , and/or a material selected from the list consisting of rice husk, cork, bamboo, sugar cane, foamed synthetic material, porous inorganic material, perlite, vermiculite, senoite and pumice.

10. The decorative panel according to claim 8, characterized in that the filling material comprises at least a first part and a second part of filling material, and preferably consists of the first part and the second part of filling material, wherein the first part is a filling material with a density of 300 kg/m ³ or less, such as 120-180 kg/m ³ or less, and/or includes a material selected from the list consisting of rice husk, cork, bamboo, sugar cane, foamed synthetic material, porous inorganic material, perlite, vermiculite, senoite and pumice, and wherein the second part is a filling material with a density of 1200 kg/m ³ or more, such as a density of 1800-3000 kg/m ³ and/or includes a material selected from the list consisting of chalk, talc, limestone, CaCO ₃ , sand and SiO ₂ .

11. A decorative panel according to claim 10, characterised in that the density of the filling material is within 25% of the density of the polymer, preferably within 20% of the density of the polymer.

12. The decorative panel according to claim 10 or 11, characterized in that the amount of filler material available in the filled synthetic material is 50%-250%, or preferably 80%-200%, expressed as a weight ratio of filler material to synthetic material.

13. The decorative panel according to any one of claims 10-12, characterized in that the amount of filler material available in the filled synthetic material is 50%-250%, or preferably 80%-200%, expressed as a weight ratio of filler material to synthetic material.

14. A decorative panel according to any one of claims 10 to 13, characterised in that the density of the filled synthetic material is within 30% or within 20% of the density of the polymer in question.

15. A method for manufacturing a decorative panel, wherein the panel comprises a substrate (2) and a top layer (3) arranged thereon, wherein the substrate (2) comprises at least a semi-crystalline polymer, wherein the method comprises a step in which the substrate (2) is provided at least in part by an extrusion operation (S1), wherein the semi-crystalline polymer is extruded through a die (56), characterised in that the method further comprises one or a combination of two or more of the following steps:

- a step of cooling the extruded semi-crystalline polymer (4) in a bath (61);

- a step of actively drawing the extruded semi-crystalline polymer (4) from the die (56);

- a step of adhering a polymer film, preferably a uniaxially or biaxially oriented polymer film (63-63A) to said extruded semi-crystalline polymer (4), or a step of casting a polymer layer directly or indirectly on said extruded semi-crystalline polymer (4);

- a step of treating the surface of the extruded semi-crystalline polymer (4) by means of rollers (62) and/or plates (59), wherein the rollers (62) and plates (59) are preferably cooled;

- a step of subsequent heat treatment of said extruded semi-crystalline polymer (4), whether or not it is forced to cool;

- A step of controlling the amount of crystallinity of said extruded semi-crystalline polymer (4).