Patent Publication Number: US-2022213695-A1

Title: Floor panel

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 17/205,475, filed Mar. 18, 2021, which is a continuation of U.S. application Ser. No. 16/345,855, filed April 29, 2019, now U.S. patent 10,988,939, which is the national stage filing of international application PCT/M2017/056855, filed Nov. 3, 2017, which claims the benefit under 35 U.S.C. 119(e) to the U.S. provisional applications U.S. 62/420,094 filed on Nov. 10, 2016 and Belgium application BE 2016/5868, filed Nov. 22, 2016, which are incorporated herein by reference. 
    
    
     This invention relates to a floor panel and to a method for manufacturing a floor panel. More particularly, the invention relates to a floor panel of the type which comprises a substrate comprising thermoplastic material, and a decor provided thereon, as well as, on at least one pair of opposite edges, coupling parts realized at least partially from the substrate, said coupling parts allowing to effect a mechanical locking, i.e. without using glue or the like, between two of such floor panels. This type of floor panels allows forming a waterproof floor covering in a smooth and user-friendly manner. Such floor covering may also be applied without any problems in humid rooms, such as bathrooms, contrary to wood-based laminate floor panels with, for example, a MDF or HOF substrate, which are less suitable for such applications. 
     BACKGROUND OF THE INVENTION 
     Document WO 2013/026559 describes such floor panel, wherein the substrate comprises one or more substrate layers of soft or flexible polyvinyl chloride, abbreviated PVC. However, such floor panel entrains a number of problems. For example, there is a not to be neglected risk of telegraphy effects. Herein, after a certain period of time imperfections in the underlying surface or subfloor on which the panels are installed will  30  become visible on the surface of the panels. When installing the panels in a room with much incident sunlight, such as a veranda or the like, there is also a high risk of the occurrence of pushed-up edges and/or the formation of gaps between the mutually coupled panels. This is the result of the expansion/shrinkage the substrate is undergoing with varying temperatures. Although the use of a glass fiber layer may increase the dimensional stability of the floor panel, this often still has proven insufficient in order to avoid the last-mentioned problems. Moreover, the panels are relatively flexible and bendable, due to which the installation thereof cannot always performed equally smooth. Moreover, the lacquer layer present on the upper side of the panel mostly scores insufficient in the field of wear resistance, scratch resistance, stain resistance and the like. 
     The floor panel which is known from document WO 2014/006593 already tackles a number of the mentioned problems. It has a rigid substrate layer formed by means of extrusion, which comprises, on the one hand, high-density polyethylene, abbreviated HOPE, or PVC and, on the other hand, powder of bamboo, wood and/or cork. This substrate layer is glued together with a veneer layer, such as a decorative vinyl layer. This floor panel already offers a considerably higher resistance against telegraphy effects. Due to the rigidity thereof, it is also easier to install. However, it also has disadvantages. So, the flatness of the floor panel cannot be guaranteed. There is a considerable risk that it will warp. Moreover, the floor panel seems to be sensitive for the forming of indentations in the upper side thereof, for example, when table or chair legs are standing thereupon. Further, delamination problems may occur, wherein the veneer layer becomes detached from the substrate layer. 
     SUMMARY OF THE INVENTION 
     The invention has the aim of offering a solution to one or more of the aforementioned and/or other problems. 
     To this aim, the invention, according to a first independent aspect thereof, relates to a floor panel of the aforementioned type, with the characteristic that the substrate comprises a rigid substrate layer of thermoplastic material and a glass fiber layer is present in the floor panel. The inventor has found that applying a glass fiber layer with a rigid substrate layer is extremely advantageous. It provides for a reduced risk of warping of the panels. Moreover, there is a less high risk of pushed-up edges and/or gap formation when installing the panels in a veranda or the like. The expansion/shrink is still there, however, this seems to lead less to the last-mentioned disadvantageous effects. Herein, it is noted that the expansion as such does not pose a problem, as this can be counteracted by providing the necessary expansion spaces. 
     It is noted that by the term substrate reference is made to that portion of the floor panel which is situated underneath the decor or the possible decor carrier. 
     The rigidity of the substrate layer preferably is obtained by making the thermoplastic material thereof rigid. This is possibly by using an appropriate amount of plasticizer or no plasticizers at all. If plasticizers are used, this preferably is in an amount of less than 15 phr, less than 10 phr or less than 5 phr. It is noted that an amount of plasticizers of less than 15 phr means that per 100 parts of thermoplastic synthetic material less than 15 parts of plasticizers are present. Examples of plasticizers which can be applied are phthalate-based plasticizers, such as di-isononyl phthalate, abbreviated DINP, or dioctyl phthalate, abbreviated DOP or DnOP, or, as an alternative for phthalate-based plasticizers, di-octyl terephthalate, abbreviated DOTP, or di-isononyl-1, 2-cyclohexane dicarboxylate, abbreviated DINCH. 
     The thermoplastic material of the rigid substrate layer preferably comprises one or more of the following thermoplastic synthetic materials: PVC, polyethylene, HOPE, polypropylene, polyester, polyethylene terephthalate, abbreviated PET, polyurethane and/or elastomer. The most preferred synthetic material is PVC. 
     The thermoplastic material of the rigid substrate layer preferably comprises an amount of filler. Fillers promote the stiffness of the panels. Various kinds of fillers may be applied, whether or not in combination: 
     an inorganic filler, such as chalk, lime and/or talc; 
     an organic filler, such as wood, bamboo and/or cork; and/or 
     a mineral filler. 
     It is also noted that the filler talc is particularly advantageous. Namely, it has shown that this filler has a positive effect on the dimensional stability of the panel. 
     The percentage of filler preferably is situated between 30 and 70 percent by weight or between 45 and 65 percent by weight. Herein, it is noted that the percentage by weight is considered in respect to the total weight of thermoplastic material in the substrate layer. 
     The proportion of filler preferably is at least 40 percent by weight, more preferably at least 50 percent by weight and still more preferably at least 60 or at least 70 percent by weight. It has shown that such rather high proportion of filler increases the dimensional stability of the substrate layer. 
     The thermoplastic material of the rigid substrate layer may comprise an impact modifier, a stabilizer, such as a Ca/Zn stabilizer, and/or a color pigment, such as carbon black. 
     It is also noted that the thermoplastic material of the substrate layer may or may not be recycled material. 
     Preferably, the rigid substrate layer is not or almost not foamed. The inventor has found that such substrate layer does not only offer a better resistance against telegraphy effects than foamed layers, but also against indentation. It is also noted that almost not foamed means that the density of the unfoamed thermoplastic material by foaming is reduced by maximum 10% and preferably by maximum 5% or by maximum 2%. The density of the not or almost not foamed substrate layer preferably is situated between 1300 and 2000 kg per cubic meter or between 1500 and 2000 kg per cubic meter. 
     However, it is not excluded that the rigid substrate layer is foamed. In fact, the inventor has found that foaming has a positive influence on the dimensional stability. Preferably, the density reduction is more than 10%. This means that the density of the unfoamed thermoplastic material is reduced by more than 10% by foaming. 
     The rigid substrate layer can be formed by means of various techniques, such as strewing, extrusion or calendering processes. The strewing process, which as such is known from documents WO 2013/179261 and BE 2015/5572, is preferred. In fact, the flatness of the substrate layer can be guaranteed better by such process. 
     The glass fiber layer may relate, for example, to a glass fiber fleece, a glass fiber cloth or a glass fiber net. 
     The glass fiber layer preferably adjoins the rigid substrate layer. In this position, the glass fiber layer may best counteract the possible warping or dimensional deformation of the substrate layer. 
     The glass fiber layer preferably is at least partially impregnated with a thermoplastic material of the rigid substrate layer. This provides for a good embedding of the glass fiber layer, due to which the working thereof is more effective. The risk of delamination is reduced as well. 
     It is also noted that the glass fiber layer preferably relates to a glass fiber fleece. Such type of glass fiber layer is bonding better to the substrate layer. A better impregnation is possible as well. 
     The substrate may comprise a second rigid substrate layer of thermoplastic material. 
     This substrate layer may show one or more of the characteristics of the first-mentioned substrate layer. 
     Preferably, the glass fiber layer is adjacent to the first-mentioned as well as to the second substrate layer. Herein, the glass fiber layer is situated between the two substrate layers. This can be obtained in different manners. 
     It is preferred that the two rigid substrate layers are provided by means of a strewing treatment. In this case, the one substrate layer can be strewn, the glass fiber layer can be provided thereon, and the other substrate layer can be strewn on this complex. Subsequently, the whole can be consolidated. Such process is known as such from document WO 2013/179261. It offers the advantage that the glass fiber layer can be embedded very well between the two substrate layers. 
     Another possibility is the one wherein the one substrate layer is provided by means of a strewing treatment, the glass fiber layer is provided thereon, this complex is consolidated and the other substrate layer only then is provided on this consolidated complex. Such process is known from document WO 2016/079225. It offers the advantage that the risk of deformation and/or damage of the glass fiber layer can be minimized, as a press element of the possibly employed press device can be directly brought into direct with the glass fiber layer. The other substrate layer may be provided, for example, by means of a calendering technique. 
     Still another possibility is manufacturing the two rigid substrate layers by means of extrusion. In that case, the extruded substrate layers and the glass fiber layer can be stacked on top of each other and subsequently can be bonded to each other. The mutual bonding can be performed in a press device, for example, in a single-daylight or multi-daylight press. 
     Another option is forming the one substrate layer by means of extrusion, transporting this extruded substrate layer and providing the glass fiber layer during said transport on said extruded substrate layer. An advantage of this process in respect to the preceding one is that it can be performed continuously. For example, the one substrate layer can be transported along guide rollers and the glass fiber layer can be supplied along with the substrate layer between these guide rollers. The other substrate layer can be provided afterwards on the glass fiber layer. Or it is possible to provide this substrate layer together with the glass fiber layer on the one substrate layer during the transport thereof. 
     The glass fiber layer can be untreated. However, it is also possible that the glass fiber layer is pretreated. This latter may provide for a better connection with the substrate layer or layers to which the glass fiber layer is adjacent. The pretreatment can include that a coating is provided on the glass fiber layer or that the glass fiber layer is impregnated. The coating or the impregnation material may relate to a plastisol, preferably a PVC plastisol. The pretreatment can take place in an offline step. 
     The weight of the glass fiber layer can be situated between 30 and 100 grams per square meter. However, preferably this weight is lower than 65 grams per square meter. This offers the advantage that the glass fiber layer can be embedded easier and faster into the substrate. Moreover, such more light-weight glass fiber results in only a slight to no reduction of the dimensional stability, at least not as the one applied with rigid substrate layers, as the inventor, rather unexpectedly, has found. 
     In the floor panel preferably a second glass fiber layer is present. The use of more than one glass fiber layer has proven more effective than the use of a single glass fiber layer. The second glass fiber layer may show one or more of the characteristics of the first-mentioned glass fiber layer. 
     In particular, the first as well as the second glass fiber layer have a weight lower than 65 or at most 50 grams per square meter. This has a positive influence on the processing speed and practically no detrimental influence on the dimensional stability, at least not in the application with rigid substrate layers. 
     The two glass fiber layers preferably are situated offset from the center of the floor panel. In this manner, their effect is better distributed over the floor panel. Preferably, the one glass fiber layer is situated in the lower half of the floor panel, while the other glass fiber layer is situated in the upper half. 
     The two glass fiber layers preferably are situated at a vertical distance from each other of at least ⅕ times or at least ¼ times the thickness of the floor panels. This provides for a good distribution of the effect of the glass fiber panels over the overall thickness of the floor panel. Most preferably, they are situated at a vertical distance from each other of approximately ⅓ the thickness of the floor panel. 
     Preferably, the two glass fiber layers enclose the first substrate layer. Herein, the upper side thereof is bordered by the one glass fiber layer, and the lower side thereof by the other glass fiber layer. The thickness of the first substrate layer in this case preferably is at least ⅕, at least ¼ or approximately ⅓ times the overall thickness of the floor panel. The two glass fiber layers preferably are situated offset from the center of the floor panel, such that the center line of the floor panel in this case runs through the first substrate layer. 
     The one glass fiber layer preferably is enclosed between the first substrate layer and a second rigid substrate layer of thermoplastic material, while the other substrate layer preferably is enclosed between the first substrate layer and a third rigid substrate layer of thermoplastic material. This results in a particularly balanced and stable sandwich structure. The second and the third substrate layer can show one or more of the characteristics of the first substrate layer. The first substrate layer preferably is situated centrally, i.e., the center line of the floor panel passes therethrough, whereas the second and third substrate layer preferably are situated in the center, with the second substrate layer in the upper half and the third substrate layer in the lower half of the floor panel. The second and the third substrate layer preferably are made thinner than the first substrate layer, however, preferably the thickness thereof is at least ⅕ or at least ¼ of the thickness of the first substrate layer. The third substrate layer preferably is made thicker than the second substrate layer, however, maximum 2.5 or maximum 2 times as thick. 
     The one or more rigid substrate layers of thermoplastic material form a rigid part of the floor panel. This rigid part preferably has an overall thickness of at least 2 mm. Namely, the inventor has found that as from such thickness the resistance against telegraphy effects and the bending stiffness is very good. Still better the overall thickness of the rigid part is at least 2.5 mm or at least 3 mm. the overall thickness of the rigid part preferably is maximum 8 mm, maximum 6 mm or maximum 4 mm. In this manner, the weight of the panels can remain limited. The overall thickness of the rigid part preferably is situated between 2 and 8 mm, between 2 and 6 mm or between 2 and 4 mm. The overall thickness of the rigid part preferably is at least 50%, at least 60% or at least 65% of the overall thickness of the floor panel. 
     The substrate preferably comprises a substrate layer which is more flexible or compressible than the first rigid substrate layer. This more flexible substrate layer offers the advantage that the sound, which is created when the installed floor panels are walked upon, can be damped. Preferably, this flexible substrate layer is situated between the first substrate layer and the decor. Preferably, this more flexible substrate layer is situated directly underneath the decor or the possible decor carrier on which the decor is provided. In that case, it also assists in efficiently obtaining deep relief structures in the upper side of the floor panel. For this purpose, it is indeed desirable to deform the material underneath the decor, which is easier when this material is relatively flexible. 
     The more flexible substrate layer preferably is constructed of thermoplastic material, wherein PVC best is used as the thermoplastic synthetic material, however, wherein the use of other synthetic materials, such as polyethylene, polypropylene, polyester, such as PET, polyurethane and/or elastomer, is not excluded. The flexibility of this substrate layer preferably is obtained by realizing the thermoplastic material thereof as soft or semi-rigid. This is possible by using an appropriate amount of plasticizers, certainly in the case that PVC is applied as the thermoplastic synthetic material. The amount of plasticizers in the more flexible substrate layer preferably is at least 15 phr and still better at least 20 phr. Examples of plasticizers which can be used, certainly in the case of PVC, are phthalate-based plasticizers, such as DINP or DOP, or, as an alternative for phthalate-based plasticizers, DOTP or DINCH. 
     When realizing the more flexible substrate layer, an extrusion, calendering or strewing technique can be applied. 
     It is preferred that the more flexible substrate layer is connected to the first or the possible second rigid substrate layer via thermal lamination, which, compared to the use of glue or the like, restricts the risk of delamination. Preferably, this is performed by a calendering process, for example, by means of a calendering device consisting of more than two calendering rollers. 
     However, it is not excluded that the more flexible substrate layer is composed of another material than thermoplastic material. For example, it is possible that this substrate layer relates to a carpet layer, or a textile layer in general, or is made of rubber or cork. In these cases, it is preferred that the respective substrate layer is connected to the first or possible second rigid substrate layer by means of glue or the like, preferably a waterproof glue, such as hot-melt glue. Herein, it is also noted that, in the case of, for example, a carpet layer, the decor actually is comprised in this carpet layer. 
     The thickness of the more flexible substrate layer preferably is situated between 0.5 and 3 mm, still better between 0.5 and 2 mm and best between 0.5 and 1 mm, or between limits included, as with these thicknesses the herein above-described advantages will show particularly well. 
     The substrate may comprise a substrate layer at its lower side, which layer preferably is more flexible or more compressible than the first rigid substrate layer. By such substrate layer situated at the lower side of the substrate, the advantage is obtained that the noise that is created when the installed floor panels are walked upon, can be damped. This substrate layer can be composed of thermoplastic material, wherein the use of synthetic materials, such as PVC, polyethylene, polypropylene, polyester, such as PET, polyurethane and/or elastomer, is possible. The respective substrate layer preferably is foamed, considering that this can improve the sound-absorbing features thereof. A preferred embodiment of such substrate layer is one that comprises XPE or cross-linked polyethylene foam. 
     When realizing said substrate layer situated at the lower side of the substrate, an extrusion, calendering or strewing technique can be used. 
     It is an option to connect this substrate layer with the first or possible third rigid substrate layer by thermal lamination, which, compared to the use of glue or the like, restricts the risk of delamination. However, it is not excluded that the respective substrate layer is connected to the first or possible third substrate layer in another manner, such as with glue or the like, in which case preferably a waterproof glue, such as hot-melt glue, is used. 
     It is also not excluded that the backing layer is composed of another material than thermoplastic material. For example, it is possible that the backing layer relates to a textile layer or is composed of cork or rubber. In these cases, it is preferred that the backing layer is connected to the core by means of glue or the like, preferably a waterproof glue, such as hot-melt glue. 
     The thickness of said substrate layer located at the lower side of the substrate preferably is situated between 1 and 4 mm, still better between 1 and 3 mm and best between 1 and 2 mm, limits included, wherein a thickness of approximately 1.5 mm has proven ideal. 
     The decor preferably relates to an imprinted or printed decor, wherein this imprinted or printed decor best depicts a natural product, such as wood or stone. In the case of wood, the decor can depict, for example, wood nerves and/or wood pores. For imprinting or printing, any of the following techniques can be used: offset printing, rotogravure printing and a digital printing technique, wherein, for example, a digital printer or inkjet printer is employed. 
     The decor can be imprinted or printed on a decor carrier. Or the decor can be imprinted or printed directly on the substrate, in which case this relates to a so-called “direct print”. Herein, it is possible that the substrate is provided with a base coat or primer, possibly a plurality of base coats or primers, prior to imprinting or printing thereon. 
     When the decor is imprinted or printed on a decor carrier, this preferably relates to a foil or film, which can be thermoplastic. This may relate, for example, to a foil or film of PVC, polyethylene, polypropylene, polyurethane, or polyester, such as PET. 
     It is also possible that the decor carrier relates to a cellulose-based layer, preferably impregnated with a resin. For example, the cellulose-based layer relates to paper, such as standard paper or a kraft paper. The resin preferably comprises melamine resin and/or a phenolic resin. 
     It is also noted that, in the case that the decor carrier relates to a cellulose-based layer, also one or more cellulose-based layers, such as paper, can be present there underneath, which improves the rigidity of the floor panel. These one or more additional cellulose-based layers preferably are impregnated with resin, such as melamine and/or phenolic resin. 
     As an alternative for an imprinted or printed decor, for example, a veneer of wood or stone can be provided on the substrate, which then forms the decor. Preferably, the possible wood veneer is treated, such that it is waterproof or largely waterproof. 
     Preferably, the floor panel comprises a wear and/or lacquer layer provided on the decor for protecting the decor and for preventing it from wear. Preferably, these layers are transparent or translucent, such that the decor remains visible. 
     The wear layer preferably relates to a foil or film, which best is thermoplastic. This may relate, for example, to a foil or film of PVC, polyethylene, polypropylene, polyurethane or polyester, such as PET. The thickness of such foil or film preferably is situated between 250 and 750 micrometers, limits included. This type of wear layer preferably is applied in the case that the decor is imprinted or printed on a foil or film. 
     It is also possible that the wear layer relates to a cellulose-based layer, preferably impregnated with a resin. For example, the cellulose-based wear layer relates to paper, such as standard paper or a kraft paper. The resin preferably comprises melamine resin and/or a phenolic resin. Preferably, the cellulose-based wear layer comprises wear-resistant particles, such as ceramic particles or corundum. This type of wear layer preferably is applied in the case that the decor is imprinted or printed on a cellulose-based layer. 
     The lacquer layer preferably is realized on the basis of urethane acrylates, polyester acrylates and/or epoxide acrylates. Preferably, this relates to a lacquer layer which can be hardened by means of UV radiation or excimer radiation. The lacquer layer can comprise ceramic particles, such as aluminum oxide and/or silica. The lacquer layer can be provided prior or after forming the possible relief in the upper side of the floor panel. Certainly, with a rather deep relief, for example, relief reaching deeper than 100 or 250 microns, it is advantageous to provide the lacquer layer prior to forming the relief, such as known from document BE 2016/5732, considering that this helps preventing interruptions in the lacquer layer. This certainly proves its usefulness when applying high-gloss wear layers, such as wear layers of PVC, as in this manner the occurrence of blinking spots resulting from such wear layers can be avoided, such as described in document BE 2016/5732. 
     It is also noted that a plurality of lacquer layers can be present above the decor. This is particularly advantageous in the case that a relief is provided in the upper side of the floor panel. In that case, a first lacquer layer can be provided prior to forming the relief, in order to provide for that these lacquer layer does not show any interruptions and to prevent the occurrence of blinking spots, and a second after the relief has been formed, wherein for this second lacquer layer a harder lacquer can be applied, which principle is known as such from BE 2016/5732. 
     It is also noted that the invention allows applying stiffer lacquers. This is because of the presence of the rigid substrate layer. In fact, this substrate layer can counteract the crimp to which the lacquer is subject, without the panel thereby warping or deforming. The application of stiffer lacquers offers the advantage that they are more effective and provide for a better mechanical and chemical resistance. 
     The upper side of the floor panel can show a relief simulating the texture of a natural product, such as wood, stone or ceramics. In the case of wood, the relief may simulate, amongst others, wood nerves and/or wood pores. Possible bevels on one or more of the edges of the upper side of the floor panel do not belong to such relief and are not considered as forming part of the relief, in view of the fact that they are not directed to simulating a natural texture, but rather to achieving a plank effect. The relief can be provided by means of mechanical and/or chemical embossing. 
     The relief preferably has a maximum relief depth which is larger than 100 microns and still better is larger than 200 or 250 microns. Such deep relief provides for that the floor panel will look and feel very natural. With such deep relief, it is particularly advantageous when a more flexible substrate layer, as described herein above, is applied. In fact, such substrate layer can be easily deformed or impressed in order to form the deep relief. 
     In the case that a relief is formed in the upper side of the floor panel, best a wear layer is present in which the relief extends. It is possible that the relief, certainly with a deep relief, extends in the wear layer, however, up into the substrate, preferably up into the possible more flexible substrate layer. 
     The relief may or may not be performed in register with the decor. Performing in register entrains the advantage that a more naturally looking and feeling floor panel is obtained. Various techniques are known in order to realize such “in register” embodiment, in particular from the following documents: EP 2 636 524, EP 2 447 063 and EP 2 447 064. 
     It is noted that, in the case that a veneer of wood or stone is provided above the substrate, the upper side of the floor panel automatically is given a relief with the texture of wood or stone, respectively. 
     The upper side of the floor panel can comprise a bevel on one or more edges thereof. This may relate to a bevel which does not reach deeper than the possible wear layer. However, it is possible that the bevel reaches deeper than the wear layer, for example, up into the substrate, in which case the bevel preferably is decorated. This is possible by providing a separate decoration on the bevel, i.e., a decoration separate from the decor, such as a lacquer, paint or transfer foil. Or the decor may extend uninterruptedly over the bevel. In that case, this may relate to a so-called “pressed bevel”, wherein the bevel is formed by impressing the upper side of the floor panel, including the decor, in the proximity of an edge thereof. 
     The floor panel preferably shows one or more of the following characteristics: 
     the floor panel bends under the own weight thereof less than 10 cm per meter and still better less than 5 cm per meter; and/or 
     the floor panel shows a modulus of elasticity or Young&#39;s modulus of at least 2000 N per square millimeter, at least 3000 N per square millimeter or at last 3500 N per square millimeter. 
     The bending can be measured by fixedly clamping the floor panel on one extremity thereof and measuring the bending of the remaining free portion. In the case of an oblong rectangular panel, the fixedly clamped extremity may concern, for example, one of the longitudinal extremities. 
     The modulus of elasticity has to be understood as the one at a room temperature of 25 degrees Celsius. 
     The overall thickness of the floor panel preferably is situated between 3 and 10 mm, or between 3 and 8 mm, or between 3.5 and 8 mm, or between 3.5 and 6 mm, or between 4 and 6 mm, limits included, wherein an ideal thickness is about 4.5 mm. 
     The mechanical locking effected by the coupling parts in the coupled condition of two of such floor panels can be operative at least or exclusively in the horizontal direction, i.e., the direction in the plane of the coupled floor panels which is perpendicular to the coupled edges. This horizontal locking can be realized by cooperating locking surfaces. The zone in which these locking surfaces cooperate, preferably is situated at least partially or entirely in the first, the possible second or the possible third rigid substrate layer, which offers the advantage that a strong locking can be provided and the formation of gaps can be minimized. It is also a possibility to situate the glass fiber layer at the height of this zone, which improves the strength of the locking. 
     The mechanical locking effected by the coupling parts in the coupled condition of two of such floor panels, can be operative at least or exclusively in the vertical direction, i.e., the direction perpendicular to the plane of the coupled floor panels. This vertical locking can be realized by cooperating locking surfaces, wherein the zone in which these locking surfaces cooperate, preferably is situated at least partially or entirely in the first, the possible second or the possible third rigid substrate layer, which offers the advantage that a strong locking can be provided, and the formation of gaps can be minimized. It is also a possibility to situate the glass fiber layer at the height of this zone, which improves the strength of the locking. 
     It is preferred that both a horizontal and a vertical locking are present, best realized by cooperating locking surfaces, wherein the zone or zones in which the locking surfaces cooperate preferably are situated at least partially in the first, the possible second or the possible third rigid substrate layer. The glass fiber layer can be situated at the height of a zone in which locking surfaces cooperate. In the case that there are a plurality of zones in which locking surfaces cooperate, these glass fiber layers, when using a plurality of glass fiber layers, or at least a part of these glass fiber layers, may be situated at the height of the aforementioned zones. 
     The coupling parts can be realized as a tongue and groove connection, the groove being bordered by an upper and a lower lip. This connection preferably comprises locking elements, for example, in the form of a protrusion at the lower side of the tongue and a recess in the upper side of the lower lip, which, in the coupled condition, counteract the moving apart of the tongue and the groove in the horizontal direction. Preferably, this tongue and groove connection shows one or more of the following characteristics, as far as they are not contradictory, which characteristics all increase the stability and strength of the locking: 
     the upper lip is at least partially realized from the first or the possible second rigid substrate layer; 
     the lower lip is at least partially realized from the first or the possible third rigid substrate layer; 
     the center line through the tongue is situated in the first rigid substrate layer; 
     the most inwardly located point of the groove is situated in the first rigid substrate layer; 
     the zone where the upper side of the tongue cooperates with the lower side of the upper lip is situated at least partially or entirely in the first or the possible second rigid substrate layer; 
     the zone where the possible locking elements cooperate is situated at least partially or entirely in the first or the possible third rigid substrate layer; 
     the glass fiber layer is situated at the height of the zone where the upper side of the tongue cooperates with the lower side of the upper lip; 
     the glass fiber layer is situated at the height of the zone where the possible locking elements cooperate; 
     the glass fiber layer is situated on the center line through the tongue; the glass fiber layer is situated at the height of the most inwardly located point of the groove; 
     in the case that the zone where the upper side of the tongue cooperates with the lower side of the upper lip is situated at another location than the zone where the possible locking elements cooperate, preferably at least two glass fiber layers are present, wherein it is preferably valid that the one glass fiber layer is situated at the height of the zone where the upper side of the tongue cooperates with the lower side of the upper lip, and the other is situated at the height of the zone where the possible locking elements cooperate; 
     the glass fiber layer extends uninterruptedly or continuously through the lower lip or the upper lip; and/or 
     the glass fiber layer extends uninterruptedly or continuously in at least one of the coupling parts. 
     The coupling parts realized as a tongue and groove connection preferably are selected from the following types: 
     the type wherein the coupling parts are configured such that they allow coupling two of such floor panels at the respective edges by means of a turning movement, wherein the floor panel with the tongue, from an inclined position in which the tongue already is partially situated in the groove, is turned downward in order to bring the tongue completely into the groove and couple the respective edges to each other; 
     the type wherein the coupling parts are configured such that they allow coupling two of such floor panels at the respective edges by means of a substantially linear movement in the plane of the floor panels and substantially perpendicular to the respective edges, preferably with the performance of a snap action; 
     the type wherein the coupling parts are configured such that they allow coupling two of such floor panels at the respective edges both by means of a turning movement as described herein above and by means of a substantially linear movement in the plane of the floor panels and substantially perpendicular to the respective edges, preferably with the performance of a snap action. 
     It is also noted that the tongue and groove connection, in the case that the floor panel is square or oblong rectangular, can be applied at each of the pair of opposite edges of the floor panel. 
     Alternatively, the coupling parts can be realized in the form of hook-shaped parts, consisting of, on the one hand, an upward-directed hook-shaped locking part with a lip and an upward-directed locking element and, on the other hand, a downward-directed hook-shaped part with a lip and a downward-directed hook-shaped part, which locking elements, in the coupled condition of two of such floor panels, counteract the moving apart of the hook-shaped parts in the horizontal direction. The mechanical locking effected by these hook-shaped parts preferably also is operative in vertical direction, and to this end they may be provided with vertically active locking elements. Preferably, the hook-shaped parts show one or more of the following characteristics, which characteristics all improve the stability and strength of the locking: 
     the lip of the downward-directed hook-shaped part is at least partially realized from the first or the possible second rigid substrate layer; 
     the lip of the upward-directed hook-shaped part is at least partially realized from the first or the possible third rigid substrate layer; 
     the zone where the upward-directed locking element cooperates with the downward-directed locking element in order to effect the horizontal locking, is situated at least partially or entirely in the first or the possible third rigid substrate layer; 
     the zone or zones where the possible vertically active locking elements cooperate, are situated at least partially or entirely in the first, the possible second or the possible third rigid substrate layer; 
     the glass fiber layer is situated at the height of the zone where the upward directed locking element cooperates with the downward-directed locking element in order to effect the horizontal locking; 
     the glass fiber layer is situated at the height of the zone or zones where the possible vertical locking elements cooperate; 
     in the case that the zone, where the upward-directed locking element cooperates with the downward-directed locking element in order to effect the horizontal locking, is situated at another location than a zone where the possible vertically active locking elements cooperate, preferably at least two glass fiber layers are present, wherein it is preferably valid that the one glass fiber layer is situated at the height of the zone where the upward-directed locking element cooperates with the downward-directed locking element in order to effect the horizontal locking, and the other is situated at the height of the zone where the possible vertically active locking elements cooperate; 
     the glass fiber layer extends uninterruptedly or continuously in the lip of the downward-directed hook-shaped part or in the lip of the upward-directed hook-shaped part; and/or the glass fiber layer extends uninterruptedly or continuously in at least one of the hook-shaped parts. 
     The vertically active locking elements may or may not comprise a separate insert, preferably an elastically deformable and/or movable insert, which as such is known from, amongst others, the documents WO 2006/043893, WO 2008/068245 and WO 2009/066153. The insert offers the advantage that the strength of the vertical locking is largely independent of the material of the floor panel itself and that mostly a stronger vertical locking can be provided compared to locking elements which are realized from the material of the floor panel itself. Certainly, in respect to reduction of the risk of the formation of gaps between the mutually coupled floor panels, such insert thus is useful. 
     The insert preferably is provided in a recess in the upward-directed or the downward directed hook-shaped part. This recess preferably is situated at least partially in the first rigid substrate layer. 
     In the case that no use is made of such insert, the vertically active locking elements preferably are realized from the material of the floor panel itself and still better from the material of the first, the possible second or the possible third rigid substrate layer. The rigid character of this substrate layers provides for that these locking elements, too, provide for a strong vertical locking. 
     The hook-shaped parts preferably can be hooked into each other by means of a substantially linear movement perpendicular to the plane of the coupled floor panels or to the plane of the floor covering. 
     It is also noted that the hook-shaped parts, in the case that the floor panel is square or oblong rectangular, can be applied at each of the pair of edges of the floor panel. 
     Preferably, the floor panel is square or oblong rectangular and can be coupled to adjacent floor panels by means of the fold-down technique. To this aim, this floor panel comprises, on the one hand, on one pair of opposite edges, coupling parts which are realized in the form of a tongue and groove connection and which are of the type allowing to couple this floor panel to an already installed, similar floor panel, which is situated in a preceding row, by means of a turning movement, and, on the other hand, on the other pair of edges, coupling parts which are realized in the form of hook-shaped parts and which allow to couple the respective floor panel, in one and the same turning movement, to an already installed, similar floor panel situated in the same row. It has shown that this fold-down technique is excellently suited for installing the floor panel according to the invention. 
     It is also noted that, instead of a glass fiber layer, any reinforcement layer can be applied. Preferably, this is a reinforcement layer which comprises reinforcing fibers, such as carbon fibers. 
     According to an independent second aspect, the invention relates to a floor panel of the aforementioned type, with the characteristic that the substrate comprises a rigid, nonfoamed substrate layer of thermoplastic material. Hereby, the floor panel, compared to floor panels with foamed substrate layers, is less sensitive to indentation effects, for example, under the influence of chair and/or table legs. 
     It is noted that this advantage also shows in the case that the rigid substrate is hardly foamed, i.e., in the case that due to the foaming the rigid substrate layer shows a density reduction of maximum 10%. 
     According to an independent third aspect, the invention relates to a floor panel of the aforementioned type, with the characteristic that the substrate comprises a substrate layer of thermoplastic material, which, by thermal lamination, is connected to a more flexible substrate layer which is situated between the decor and the rigid substrate layer. Hereby the risk of delamination is reduced. 
     According to an independent fourth aspect, the invention relates to a floor panel of the aforementioned type, with the characteristic that in the floor panel at least two glass fiber layers are present, each having a weight of less than 65 g per square meter or even at most 50 g per square meter. 
     It is also noted that each of the second to fourth aspects can be combined with one or more of the characteristics of the first aspect without necessitating that the floor panel must show the characteristic of this first aspect. 
     According to an independent fifth aspect, the invention relates to a method for manufacturing a floor panel with a substrate, comprising thermoplastic material, and a decor provided thereon, wherein the method comprises the following steps: 
     providing a first rigid substrate layer of thermoplastic material by means of a first strewing treatment; 
     providing a glass fiber layer on the strewn substrate layer; providing a second rigid substrate layer of thermoplastic material on the glass fiber layer, by means of a second strewing treatment; 
     consolidating the strewn substrate layers and the glass fiber layer under the influence of pressure and/or heat; 
     providing, on the consolidated second substrate layer, a more flexible or more compressible substrate layer of thermoplastic material by applying this thermoplastic material in liquid condition. 
     The particularity of the method is that the rigid substrate layers are consolidated and only then the more flexible substrate layer is provided thereon. This allows regulating the consolidation parameters, such as pressure and/or temperature, in an optimum manner in function of the features of the thermoplastic material of the rigid substrate layers, which are different from those of the more flexible substrate layer, considering the difference in rigidity/flexibility. 
     The thermoplastic material of the first and/or second substrate layer may be strewn in the form of grains or powder. Preferably, this material, or at least a part thereof, is strewn in granulate form, however, it may be advantageous to strew it as a dry blend, certainly in the case that this material, or a part thereof, must be foamed. Such dry blend in fact guarantees the features of the foaming agents added to the material, as described in document BE 2015/5572, in a better manner. 
     The consolidation may be performed in a press device, preferably a double-belt press device. This press device may comprise an S-roller, which can provide for a calibration of the strewn material. 
     Preferably, the more flexible substrate layer is provided on the second substrate layer by means of a calendering device. The calendering device preferably comprises more than two calendering rollers. 
     It is clear that the method also can comprise providing the decor and possible wear and/or lacquer layers. 
     The aforementioned layers preferably form a continuous material web, which finally is divided into individual pieces, for example, by means of cutting treatments, for forming the floor panels. 
     After dividing into individual pieces, the floor panels, along one or more edges, can be provided with coupling parts which allow effecting a mechanical coupling between two of such floor panels. Providing these coupling parts preferably is performed by means of cutting tools, such as milling tools. 
     The floor panel which is obtained according to the invention further may show one or more of the characteristics of the floor panel according to said first, second, third and/or fourth aspects. 
     It is noted that the present invention is not applicable with floor panels only. It can be applied in an advantageous manner with any type of panels, such as wall panels, ceiling panels or door panels. 
     The invention can also be applied more broadly than with panels only. It can be advantageously applied with any type of floor, wall, ceiling or door elements. Examples thereof are floor elements on roll or wall-to-wall floor elements, such as wall-to-wall vinyl. 
     It is also noted that with each of the mentioned value intervals the limits are included, if not explicitly stated otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With the intention of better showing the characteristics of the invention, herein below, as an example without any limitative character, some preferred embodiments are described, with reference to the accompanying drawings, wherein: 
         FIG. 1  represents a floor panel according to the invention; 
         FIG. 2  represents a cross-section according to line  11 - 11  in  FIG. 1 ; 
         FIGS. 3 and 4  represent how the edges of  FIG. 2  can be coupled; 
         FIG. 5 , at a larger scale, represents what is indicated by F 5  in  FIG. 2 ; 
         FIGS. 6 to 13  represent variants of  FIG. 2 ; 
         FIGS. 14 and 15  represent how floor panels can be coupled according to the fold-down technique; 
         FIG. 16  represents coupling parts which can be applied with such fold-down floor panels; 
         FIGS. 17 to 19  represent variants to  FIG. 16 ; 
         FIG. 20  represents a method according to the invention; and 
         FIGS. 21 and 22  represent variants. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  represents a floor panel  1  according to the invention. The represented floor panel  1  comprises a decor  2 , which relates to printed wood decor. This relates to an oblong rectangular floor panel  1 , which as a result has a pair of long edges  3 - 4  and a pair of short edges  5 - 6 . Each pair of edges is provided with coupling parts, which are indicated by the reference numbers  7 - 8  and  9 - 10 , respectively. 
     The shape of the coupling parts  7 - 8  is evident from  FIG. 2 . This relates to a tongue and groove connection comprising a tongue  11  and a groove  12 , the groove being bordered by an upper lip  13  and a lower lip  14 . The lower lip  14  protrudes to beyond the upper lip  13 . Additionally, the connection comprises locking elements  15 - 16 , in the form of a protrusion  15  on the lower side of the tongue  11  and an upward-directed locking element  16  in the portion of the lower lip  14  that protrudes beyond the upper lip  13 , which, by cooperating locking surfaces  17 - 18 , counteract the moving apart of the tongue  11  and the groove  12  in the horizontal direction H. The upper side  19  of the tongue  11  cooperates with the lower side  20  of the upper lip  13  in order to counteract the separation in the vertical direction V. 
       FIGS. 3 and 4  show how the coupling parts  7 - 8  can be coupled by means of a turning movement ( FIG. 3 ) as well as a substantially horizontal snap movement ( FIG. 4 ). 
       FIG. 2  also shows the construction of the floor panel  1 . It is constructed of a substrate  21 , a decor carrier  22  with decor  2 , a wear layer  23  and a lacquer layer  24 . 
     The substrate  21  consists of two substrate layers  21 A and  21 B realized on the basis of PVC. 
     The substrate layer  21 A is rigid. For this purpose, no plasticizers are present in this layer  21 A, or plasticizers are present in an amount of less than 15 phr only. Examples of plasticizers which can be used have already been mentioned. Also, the substrate layer  21 A comprises a proportion of filler situated between 30 and 70 percent by weight. Preferably, chalk, talc and/or lime is used, possibly supplemented with wood, bamboo and/or cork particles. Further, the substrate layer  21 A can comprise an impact modifier, a stabilizer, such as a Ca/Zn stabilizer, and/or a color pigment, such as carbon black. The thickness T 1  of the substrate  21 A is at least 2 mm. The result is that the substrate layer 21A has a high bending stiffness. This is advantageous, considering that the risk of warping of the floor panel  1  and of forming pushed-up edges under incident sunlight already is counteracted to a certain extent. 
     This risk is significantly reduced further due to the presence of the glass fiber fleece  25 . Although it does not seem to be able to prevent the expansion/shrinkage of the substrate  21  with varying temperatures, it indeed counteracts the warping or pushing up. This actually is the most important, considering that the expansion/shrinkage as such can be counteracted by providing suitable expansion spaces, which also is known as such in the field of the wood laminate floors. The glass fiber fleece  25  is enclosed between the substrate layer  21 A and  21 B. In this manner, it can perform its function at its best. Possibly, the glass fiber fleece  25  is at least partially impregnated with thermoplastic material of the substrate layers  21 A and/or  21 B. This provides for a strong embedding in the substrate  21 , such that it can perform its function even better. The position of the glass fiber layer  25  provides for that it extends uninterruptedly in both coupling parts  7 - 8 . This is positive for the effectivity thereof, certainly at the respective edges  3 - 4  of the panel  1 . 
     The rigid substrate layer  21 A is obtained by means of a strewing process. By such process, a very good connection with the glass fleece  25  can be obtained. In such process, the glass fleece  25  can also have a support function. Possibly, the glass fleece  25  can also form a separation between the strewn layer  21 A and the layer  21 B in case the latter also would be strewn. This is certainly useful prior to consolidating, as this prevents a mutual mixing of the strewn material among the layers. 
     Also, the substrate layer  21 A is not foamed. In comparison with foamed layers, hereby a better resistance against telegraphy and indentation effects is offered. The density of the layer  21 A is situated between 1300 and 2000 kg per cubic meter. 
     The zone where the upper side  19  of the tongue and the lower side  20  of the upper lip cooperate, is situated entirely in the rigid substrate layer  21 A, just like the zone where the locking elements  15 - 16  cooperate. This provides for that a strong mechanical coupling can be effected, wherein gap formation will arise less easily. The upper lip  13  is partially realized from the layer  17 A, and the lower lip  14  even entirely. This provides for a reduced risk of breaking of one or both of the lips  13 - 14 . Certainly, with the lower lip  14 , this is advantageous as this lip  14  may not break as a result of the possible bending it is subjected to during the coupling of the edges  3 - 4 . Otherwise, the coupling will be lost. 
     The substrate layer  21 B is more flexible than the layer  21 A. To this aim, in this layer  21 B more plasticizers are present, namely at least 15 phr. This flexible layer  21 B provides for that, regardless of the relatively stiff panel  1 , no ticking sound is created when this panel  1  is walked upon. Thus, due to the soft character, it has sound absorbing properties. Moreover, such layer  21 B is easier to deform in order to create a deep relief in the upper side of the panel  1 . The proportion of filler in this layer  21 B is situated between 30 and 70 percent by weight. Further, the substrate layer  21 B can comprise an impact modifier, a stabilizer, such as a Ca/Zn stabilizer, and/or a color pigment, such as carbon black. The thickness T 2  of the substrate layer  21 B is situated between 0.5 and 1 mm. 
     The layers  17 A and  17 B are connected to each other by means of thermal lamination. In this manner, a reduced risk of delamination is obtained in comparison with the use of glue or the like. 
     The decor carrier  22  on which the decor is printed relates to a PVC film or foil. 
     The transparent wear layer  23  relates to a PVC layer with a thickness situated between 250 and 750 micrometers. 
     The overall thickness T of the floor panel  1  is situated between 3.5 and 6 mm. 
       FIG. 5  better shows the lacquer  24  which is provided on the wear layer  23 . This relates to a lacquer realized on the basis of urethane acrylate. The relief  26  provided in the upper side of the panel  1  is visible, too. 
       FIG. 6  shows coupling parts  7 - 8  similar to those from  FIG. 2 , however, the substrate  21  is constructed differently. The layer  21 A is constructed similar to the layer  21 A of  FIG. 2 , however, thinner. Anyhow, a second rigid substrate layer  21 C is present in the substrate  21 As well, which also is made of PVC. The substrate layer  21 C contains no plasticizers, or plasticizers in an amount of less than 15 phr only. The substrate layer  21 C also comprises a proportion of filler situated between 30 and 70 percent by weight. Further, the substrate layer  21 C can comprise an impact modifier, a stabilizer, such as a Ca/Zn stabilizer, and/or a color pigment, such as carbon black. The overall thickness T 1  of the substrate layers  21 A and  21 C is at least 2 mm. The result is that the whole of both substrate layers  21 A and  21 C gives a high bending stiffness to the panel  1 , which even is increased by the enclosed glass fleece  25 . The position of the glass fleece  25  is such that it extends uninterruptedly through both coupling parts  7 - 8 . And it is positioned at the height of the center line of the tongue  11  and goes through the most inwardly located point of the groove  12 . Thus, at those locations additional support is given, which is beneficial for the strength of the tongue  11  and groove  12 . 
     The rigid layers  21 A and  21 C are formed by means of a strewing process which is known as such from WO 213/179261. It offers the advantage that the glass fleece  25  can be embedded very well into the rigid whole, with a particularly stable sandwich as a result. 
     The rigid layer  21 C also is not foamed. 
       FIG. 7  shows coupling parts  7 - 8  similar to those from  FIG. 6 , however, the substrate  21  is constructed differently. The substrate layers  21 A and  21 C are constructed similar to the layers  21 A and  21 C of  FIG. 6 . However, there is a third rigid substrate layer  21 D, which also is made of PVC. The substrate layer  21 D contains no plasticizers, or plasticizers in an amount of less than 15 phr only. Also, the substrate layer  21 D comprise a proportion of filler situated between 30 and 70 percent by weight. Further, the substrate layer  21 D can comprise an impact modifier, a stabilizer, such as a Ca/Zn stabilizer, and/or a color pigment, such as carbon black. The overall thickness T 1  of the substrate layers  21 A,  21 C and  21 D is at least 2 mm. The result is that the whole of the substrate layers  21 A,  21 C and  21 D gives a high bending stiffness to the panel  1 , which even is increased by the presence of two enclosed glass fleeces  25 A and  25 B. The two glass fleeces  25 A and  25 B are located off the center of the panel  1  at a distance D from each other of at least ⅕ the thickness T of the panel  1 . The substrate layers  21 C and  21 D are realized thinner than the center layer  21 A, however, have a thickness of at least ⅕ the thickness of the center layer  21 A. The result is a particularly balanced and stable sandwich construction. The substrate layers  21 A,  21 C and/or  21 D as such may comprise a plurality of substrate layers and thus be multi-layered. The substrate layer  21 A, for example, may comprise a plurality of substrate layers which may or may not have a mutually differing composition, such as a mutually differing proportion of filler or plasticizer. The same is applicable to the layers  21 C and  21 D and more generally to all substrate layers mentioned in this document. 
     The two glass fleeces  25 A and  25 B have a weight smaller than  65  gram per square meter. This has a positive influence on the process speed and practically no detrimental influence on the dimensional stability, at least not in the application with rigid substrate layers. 
       FIG. 8  shows a variant of  FIG. 7 , wherein the substrate  21  at the lower side comprises a sound-absorbing substrate layer  21 E of XPE foam. The thickness of this layer  21 E is situated between 1 and 2 mm. 
       FIG. 9  shows a variant of  FIG. 7 , wherein the glass fleeces  25 A- 25 B are positioned somewhat differently. The glass fleece  25 A goes centrally through the zone where the upper side  19  of the tongue  11  cooperates with the lower side  20  of the upper lip  13 , whereas the glass fleece  25  goes centrally through the zone where the locking elements  15 - 16  cooperate. This provides for an excellent horizontal and vertical locking. 
       FIG. 10  shows a variant of  FIG. 9 . The glass fleece  25 A is positioned similarly, however, the glass fleece  25 B extends uninterruptedly in the coupling part  8 . It extends continuously through the lower lip  14 . This is beneficial for the strength of this lip  14 . 
       FIG. 11  shows a similar construction of the substrate  21 As in  FIG. 10 , however, the coupling parts  7 - 8  have another configuration. The lower side of the tongue  11  is convex, while the upper side of the lower lip  14  is concave. 
       FIGS. 12 and 13  show two more variants, where the lower side of the tongue  11  and the upper side of the lower lip  14  comprise a flat part. 
       FIGS. 14 and 15  represent how floor panels  1  can be coupled to each other by means of the fold-down technique. 
     To this aim, the short pair of edges  5 - 6  of the panel  1  is provided with the coupling parts  9 - 10  shown in  FIG. 16 . Those are realized in the form of a downward-directed hook  27  and an upward-directed hook  28 . The downward hook  27  has a lip  29  with a downward-directed locking element  30 , whereas the upward hook  28  has a lip  31  with an upward-directed locking element  32 . The locking elements  30  and  32  cooperate, via locking surfaces  33 - 34 , in order to counteract the moving apart of the hooks  27 - 28  in horizontal direction. The hooks  27 - 28  are also provided with vertically active locking elements  35 - 36 . The vertically active locking element  35  is made as a separate insert, which is provided in a recess  37  in the downward hook  27 . This recess is situated partially in the rigid layers  21 A and  21 C. It is also possible to provide the insert  35  in the upward hook  28 . 
     The lip  29  is formed partially from the rigid layers  21 A and  21 C. The lip  31  is formed entirely from the rigid layers  21 A and  21 D. The zone where the locking elements  30  and  32  cooperate is situated entirely in the rigid layer  21 A. All these measures are advantageous for the strength of the locking. The zone where the insert  35  cooperates with the locking element  36  is situated in the more flexible layer  21 B. However, it is not excluded that this last zone is situated at least partially or entirely in the rigid layers  21 A and/or  21 C. 
     The glass fiber layer  25 A is situated at the height of the recess  37 . This provides for additional stability there, where the floor panel, due to the recess  37 , is somewhat weaker. 
     The glass fiber layer  25 A extends continuously in the lip  31  of the upward-directed hook  28 . 
       FIG. 17  shows a variant of  FIG. 16 . Here, the insert  36  is provided in a recess  37  in the upward hook  28 . The zone where the insert  36  cooperates with the locking element  35 , however, indeed is situated in a rigid substrate layer, namely in the rigid layer  21 A. This provides for a very good vertical locking. 
       FIG. 18  shows a variant of  FIGS. 16 and 17 , wherein the vertically active locking elements are realized from the material of the panel  1 . There, even two pairs of vertically active locking elements are present, namely the locking elements  35 - 36  as well as the locking surfaces  33 - 34 , which provide for the horizontal as well as the vertical locking. All the vertical locking elements are made from the rigid layers  21 A and  21 C. Moreover, the glass fleece is situated at the height of the zone where the locking elements  35 - 36  cooperate. The glass fleece  25 B extends continuously through the lip  31 . This provides for that the lip  31  is realized very stable and the risk of damaging it, for example, during the elastic bending of the lip  31  during coupling, is very small, in spite of the recess provided in the lower side of the lip  31 , which recess increases the bendability of the lip  31  and, thus, the ease of installation. 
       FIG. 19  shows a variant of  FIG. 18 , wherein the vertically active locking elements  35 - 36  are situated at the end of the lip  31 . The glass fleece  25 B goes therethrough. 
       FIG. 20  represents a method according to the fifth aspect of the invention. This method can be used in order to obtain the substrate construction of the panels  1  of, for example,  FIG. 7 . 
     By means of strewing treatments successively the rigid substrate layers  21 D,  21 A and  21 Care provided. The rigid thermoplastic material thereof is strewn onto a transport belt  39  by means of strewing devices  38 . On the strewn layers  21 D and  21 A a glass fleece  25 B and a glass fleece  25 A, respectively, is provided. To this aim, the glass fleeces  25 A and  25 B are unrolled from rollers  40  and provided on the respective substrate layers  21 D and  21 A. The formed complex subsequently is transported to a double-belt press  41 , in which it is consolidated under the influence of pressure and/or heat. The press device  41  comprises, in transport direction, heating elements  42 , an S-roller  43  and cooling elements  44 . The heating elements  42  heat the complex brought into the press device  41 , as a result of which the individual layers can be connected to each other more easily and better. The use of the S-roller  43  is advantageous as it provides for a calibration of the respective layers. The cooling elements  44  finally cool the consolidated complex, such that it can be processed more rapidly. Subsequently, the more flexible substrate layer  21 B is provided on the consolidated whole, by means of calendering device  45  which consists of more than one calendering roller  46 . 
     It is clear that in subsequent steps the decor carrier  22  with decor  2 , the wear layer and the lacquer layer,  23  and  24 , can be applied. 
       FIG. 21  shows a variant of  FIG. 20 . Here, the glass fleece  25  is brought into contact with a press element in the press device  43 . This is different to  FIG. 20 , where each glass fleece is enclosed between rigid substrate layers. 
       FIG. 22  shows another alternative manner of providing a glass fleece  25  on a rigid substrate layer. Reference number  47  indicates an extrusion device with which the rigid substrate layer  21 A is manufactured. This substrate layer  21  subsequently is transported between guide rollers  48 . The glass fleece  25  is wound off a roll  49  and provided, between two of such guide rollers, on the substrate layer  21 A. It is clear that this whole can be processed further and possibly can be supplemented with subsequent substrate layers and/or glass fleeces. It is also noted that this technique and be applied in an advantageous manner with any type of substrate layer of thermoplastic material, independently of whether this relates to a rigid, semi-rigid or flexible substrate layer. 
     The present invention further relates to several preferred embodiments as defined in the below numbered paragraphs: 
     1. Floor panel ( 1 ) with a substrate ( 17 ), comprising thermoplastic material, a decor ( 2 ) provided thereon, and, on at least one pair of opposite edges ( 3 - 4 ,  7 - 8 ), coupling parts ( 5 - 6 ,  9 - 10 ) realized at least partially from the substrate ( 17 ), said coupling parts allowing to effect a mechanical locking between two of such floor panels ( 1 ), characterized in that the substrate ( 17 ) comprises a rigid substrate layer ( 17 A) of thermoplastic material, and a glass fiber layer ( 25 ) is present in the floor panel ( 1 ). 
     2. Floor panel according to paragraph 1, wherein the rigid substrate layer ( 17 A) comprises plasticizers in an amount of less than 15 phr, less than 10 phr or less than 5 phr, or does not comprise any plasticizers. 
     3. Floor panel according to paragraph 1 or 2, wherein the thermoplastic material of the rigid substrate layer ( 17 A) comprises PVC. 
     4. Floor panel according to any of the preceding paragraphs, wherein the thermoplastic material of the rigid substrate layer ( 17 A) comprises a proportion of filler, which proportion preferably is situated between 30 and 70 percent by weight or between 45 and 65 percent by weight. 
     5. Floor panel according to paragraph 4, wherein the proportion of filler comprises an inorganic filler, such as chalk, lime and/or talc, and/or an organic filler, such as wood, bamboo and/or cork. 
     6. Floor panel according to any of the preceding paragraphs, wherein the rigid  25  substrate layer ( 17 A) is not foamed. 
     7. Floor panel according to paragraph 6, wherein the density of the rigid substrate layer ( 17 A) is situated between 1300 and 2000 kg per cubic meter or between 1500 and 2000 kg per cubic meter. 
     8. Floor panel according to any of the preceding paragraphs, wherein the glass fiber layer ( 25 ) relates to a glass fiber fleece. 
     9. Floor panel according to any of the preceding paragraphs, wherein the glass fiber layer ( 25 ) adjoins to the rigid substrate layer ( 17 A). 
     10. Floor panel according to any of the preceding paragraphs, wherein the substrate comprises a second rigid substrate layer ( 17 B) of thermoplastic material, which preferably is not foamed. 
     11. Floor panel according to paragraph 10, wherein the glass fiber layer ( 25 ) is enclosed between the first and the second rigid substrate layer ( 17 A- 17 B). 
     12. Floor panel according to any of the preceding paragraphs, wherein a second glass fiber layer ( 25 B) is present in the floor panel ( 1 ). 
     13. Floor panel according to paragraph 12, wherein the first and the second glass fiber layer ( 25 A- 25 B) each have a weight smaller than 65 or at most 50 gram per square meter. 
     14. Floor panel according to paragraph 12 or 13, wherein the first and the second glass fiber layer ( 25 A- 25 B) are situated off the center of the floor panel ( 1 ). 
     15. Floor panel according to any of the paragraphs 12 to 14, wherein the first and the second glass fiber layer ( 25 A- 25 B) are situated at a vertical distance (V) of at least ⅕ times or at least ¼ times the thickness of the floor panel (T) from each other. 
     16. Floor panel according to any of the paragraphs 12 to 15, wherein the first and the second glass fiber layer ( 25 A- 25 B) enclose the rigid substrate layer ( 17 A), which in this case preferably is situated in the center of the floor panel. 
     17. Floor panel according to any of the paragraphs 12 to 16, wherein the first glass fiber layer ( 25 A) is enclosed between the rigid substrate layer ( 17 A) and the possible second rigid substrate layer ( 17 B), and the second glass fiber layer ( 25 B) is enclosed between the rigid substrate layer ( 17 A) and a third rigid substrate layer ( 17 C) of thermoplastic material, which third rigid substrate layer ( 17 C) preferably is not foamed. 
     18. Floor panel according to paragraph 17, wherein the second and the third substrate layer ( 17 B- 17 C) are made thinner than the first rigid substrate layer ( 17 A), however, preferably have at least ⅕ times or at least ¼ times its thickness. 
     19. Floor panel according to paragraph 16 or 17, wherein the third substrate layer ( 17 C) is made thicker than the second substrate layer ( 17 B), however, preferably maximum 2.5 or maximum 2 times as thick. 
     20. Floor panel according to any of the preceding paragraphs, wherein the one or more rigid substrate layers ( 17 A- 17 B- 17 C) of thermoplastic material have an overall thickness of at least 2 mm. 
     21. Floor panel according to any of the preceding paragraphs, wherein the one or more rigid substrate layers ( 17 A- 17 B- 17 C) of thermoplastic material have an overall thickness of at least half of the overall thickness (T) of the floor panel ( 1 ). 
     22. Floor panel according to any of the preceding paragraphs, wherein the substrate, between the decor and the rigid substrate layer ( 17 A), comprises a substrate layer ( 17 D) of thermoplastic material which is more flexible or more compressible than the rigid substrate layer ( 17 A). 
     23. Floor panel according to paragraph 22, wherein the more flexible substrate layer ( 17 D) is situated directly underneath the decor or the possible decor carrier on which the decor is provided. 
     24. Floor panel according to paragraph 21 or 22, wherein the more flexible substrate layer ( 17 D) is connected to the underlying part of the substrate ( 17 ) by means of thermal lamination. 
     25. Floor panel according to any of the preceding paragraphs, wherein the decor ( 2 ) relates to an imprinted or printed decor. 
     26. Floor panel according to any of the preceding paragraphs, wherein the floor panel ( 1 ) comprises a wear and/or lacquer layer ( 21  and/or  29 ) provided above the decor ( 2 ). 
     27. Floor panel according to any of the preceding paragraphs, wherein the floor panel ( 1 ) will bend under its own weight less than 10 cm per meter or less than 5 cm per meter. 
     28. Floor panel according to any of the preceding paragraphs, wherein the floor  10  panel ( 1 ) has a modulus of elasticity of at least 2000 N per square millimeter. 
     29. Floor panel according to any of the preceding paragraphs, wherein the overall thickness (T) of the floor panel ( 1 ) is situated between 3.5 and 6 mm. 
     30. Floor panel according to any of the preceding paragraphs, wherein the coupling parts ( 5 - 6 ) are realized as a tongue and groove connection, the groove ( 12 ) being bordered by an upper ( 13 ) and a lower lip ( 14 ), and wherein this connection comprises locking elements ( 15 - 16 ). 
     31. Floor panel according to paragraph 30, wherein the tongue and groove connection shows one or more of the following features, as far as they are not contradictory:
         the upper lip ( 13 ) is at least partially realized from the first ( 17 A) and/or the possible second rigid substrate layer ( 17 B);   the lower lip ( 14 ) is at least partially or entirely realized from the first ( 17 A) or the possible third rigid substrate layer ( 17 C);   the center line through the tongue ( 11 ) is situated in the first rigid substrate layer ( 17 A);   the most inwardly located point of the groove ( 12 ) is situated in the first rigid substrate layer ( 17 A);   the zone where the upper side of the tongue ( 11 ) cooperates with the lower side of the upper lip ( 13 ) is situated at least partially or entirely in the first ( 17 A) or the possible second rigid substrate layer ( 17 B);   the zone where the locking elements ( 15 - 16 ) cooperate is situated at least partially or entirely in the first ( 17 A) and/or the possible third rigid substrate layer ( 17 C);   the glass fiber layer ( 25 ) is situated at the height of the zone where the upper side of the tongue ( 11 ) cooperates with the lower side of the upper lip ( 13 );   the glass fiber layer ( 25 ) is situated at the height of the zone where the locking elements ( 15 - 16 ) cooperate;   the glass fiber layer ( 25 ) is situated on the center line through the tongue ( 11 );   the glass fiber layer ( 25 ) is situated at the height of the most inwardly located point of the groove ( 12 );       

     in the case that the zone where the upper side of the tongue ( 11 ) cooperates with the lower side of the upper lip ( 13 ) is situated at another location than the zone where the locking elements ( 15 - 16 ) cooperate, preferably at least two glass fiber layers ( 25 A- 25 B) are present, wherein it is preferably valid that the one glass fiber layer ( 25 A) is situated at the height of the zone where the upper side of the tongue ( 11 ) cooperates with the lower side of the upper lip ( 13 ), and the other is situated at the height of the zone where the locking elements ( 15 - 16 ) cooperate;
         the glass fiber layer extends uninterruptedly or continuously in the lower lip or in the upper lip; and/or   the glass fiber layer ( 25 ) extends uninterruptedly or continuously in at least one of the coupling parts ( 5 - 6 ).       

     32. Floor panel ( 1 ) with a substrate ( 17 ), comprising thermoplastic material, a decor ( 2 ) provided thereon, and, on at least one pair of opposite edges ( 3 - 4 ,  7 - 8 ), coupling parts ( 5 - 6 ,  9 - 10 ) realized at least partially from the substrate ( 17 ), said coupling parts allowing to effect a mechanical locking between two of such floor panels ( 1 ), characterized in that the substrate ( 17 ) comprises a rigid, non-foamed substrate layer ( 17 A) of thermoplastic material. 
     33. Floor panel ( 1 ) with a substrate ( 17 ), comprising thermoplastic material, a decor ( 2 ) provided thereon, and, on at least one pair of opposite edges ( 3 - 4 ,  7 - 8 ), coupling parts ( 5 - 6 ,  9 - 10 ) realized at least partially from the substrate ( 17 ), said coupling parts allowing to effect a mechanical locking between two of such floor panels ( 1 ), characterized in that the substrate comprises a rigid substrate layer ( 17 A) of thermoplastic material, which, via thermal lamination, is connected to a more flexible substrate layer ( 17 D) which is situated between the decor ( 2 ) and the rigid substrate layer ( 17 A). 
     34. Floor panel ( 1 ) with a substrate ( 17 ), comprising thermoplastic material, a decor ( 2 ) provided thereon, and, on at least one pair of opposite edges ( 3 - 4 ,  7 - 8 ), coupling parts ( 5 - 6 ,  9 - 10 ) realized at least partially from the substrate ( 17 ), said coupling parts allowing to effect a mechanical locking between two of such floor panels ( 1 ), characterized in that in the floor panel at least two glass fiber layers ( 25 A- 25 B) are present, each having a weight of less than 65 g per square meter or even at most 50 g per square meter. 
     35. Method for manufacturing a floor panel ( 1 ) with a substrate ( 17 ), comprising thermoplastic material, and a decor ( 2 ) provided thereon, wherein the method comprises the following steps:
         providing a first rigid substrate layer ( 17 A) of thermoplastic material by means of a first strewing treatment;   providing a glass fiber layer ( 25 ) on the strewn substrate layer ( 17 A);   providing a second rigid substrate layer ( 17 B) of thermoplastic material on the glass fiber layer ( 25 ), by means of a second strewing treatment;   consolidating the strewn substrate layers ( 17 A- 17 B) and the glass fiber layer ( 25 ) under the influence of pressure and/or heat;   providing, on the consolidated second substrate layer ( 17 B), a more flexible or more compressible substrate layer ( 17 D) of thermoplastic material by applying this thermoplastic material in liquid condition.       

     36. Method according to paragraph 35, wherein the consolidation is performed in a press device ( 47 ). 
     37. Method according to paragraph 35 or 36, wherein the more flexible substrate layer ( 17 D) is provided on the second substrate layer ( 17 D) by means of a calendaring device. 
     38. Method according to any of the paragraphs 35 to 37, wherein the method also comprises providing the decor ( 2 ) and a possible wear and/or lacquer layer ( 21  and/or  29 ). 
     39. Method according to any of the paragraphs 35 to 38, wherein the aforementioned layers form a continuous material web, which finally is divided into individual pieces for forming the floor panels ( 1 ). 
     40. Method according to any of the paragraphs 35 to 39, wherein the method is employed for manufacturing a floor panel ( 1 ) according to any of the paragraphs 1 to 34. 
     The present invention is in no way limited to the herein above-described embodiments; on the contrary, such methods, floor panels and carrier material can be realized according to various variants without leaving the scope of the present invention.