Multilayered structure for producing a free-standing floor covering

Abstract

The invention relates to a PVC-based windable multilayered structure (1) for producing a free-standing floor covering, having a total thickness of between 1.4 mm and 2.5 mm. According to the invention, the multilayered structure comprises: - a wear layer made of PVC having a thickness of between 0.3 and 1.2 mm; - a reinforcing frame; - a compact backing layer made of PVC having a thickness of between 0.3 and 1.3 mm, and a mass per unit area of between 360 and 2000 g / m².

Description

Description Title of the invention: Multi-layer structure for the production of a loose-lay floor covering Technical field

[0001] The present invention relates to the field of floor coverings presented in rolls and intended for loose laying, for example used to cover existing floor coverings, without removing the latter.

[0002] The invention finds an advantageous application for covering the type of resilient floor coverings well known to those skilled in the art under the acronym VSM (Vinyl On Foam), notably defined by standard NF EN ISO 11638. Prior art

[0003] Homogeneous floor coverings are known from the state of the art, comprising a single layer of plasticized PVC forming a pattern within the thickness of the layer. This type of flooring has very good wear resistance and is laid using an adhesive, for example acrylic, to be applied to the surface to be covered.

[0004] Homogeneous flooring, however, is not suitable for loose laying. Without adhesive support on the substrate, traffic will create waves on the surface of the flooring, particularly in an environment where heavy loads such as hospital beds are used. Currently, there are no floorings with a pattern extending through the thickness of the surface layer and suitable for loose laying.

[0005] It is also known from the state of the art to want to cover, in loose installation, a VSM type covering, that is to say a heterogeneous floor covering on PVC-based foam, with another covering for the purpose of changing the decor or renovating.

[0006] This practice is not really regulated and is not subject to any certification, nor to any technical application document which would have been issued by an approved commission responsible for formulating this type of technical opinion or certification.

[0007] A VSM type coating has certain puncture resistance properties, and current practices provide no guarantee that these properties will be retained.

[0008] Some have already tried to cover a VSM coating with a VSM coating, without any real guarantee as to the preservation of the aforementioned performances, but with the disadvantage of having to cut the bottoms of the doors because the total thickness becomes too great.

[0009] For example, the Applicant uses a roll-up multi-layer structure, made from PVC, and without coupling means for the creation of a loose-lay floor covering.

[0010] This structure includes a total thickness of between 1.15 and 1.3 mm with a surface mass of 1100 g / m 2 , And : - a PVC coated wear layer with a thickness of 0.15 mm; - a glass veil comprising a surface mass of 40 g / m 2, impregnated on its lower face with a bonding layer in the form of a gelled plastisol, such as a PVC plastisol, and on its upper face with a plastisol, such as a PVC plastisol, gelled and printed with a decorative layer, and with a total thickness of 0.9 mm; - a compact PVC coated backing layer with a thickness of 0.12 mm.

[0011] However, this structure does not meet the constraints of free installation on VSM because it is too flexible and does not allow the punching resistance performance to be maintained.

[0012] To facilitate free laying, the structure must be balanced and, to do this, it is known to add fillers in the PVC backing layer or to increase its thickness to have a thickness greater than 1.4 mm.

[0013] The resulting disadvantage is that the overall thickness of the structure becomes too great, which means that the bottoms of the doors have to be cut when it is to cover an existing VSM type covering which is already between 2.5 and 3.5 mm thick. Furthermore, this results in an excessive weight, in the order of 5 to 7 kg / m 2 , and therefore logistical difficulties and environmental impact issues. Statement of the invention

[0014] One of the aims of the invention is therefore to propose a rollable multi-layer structure for producing a loose-lay floor covering, which may include a surface layer having a decoration in its thickness, which also makes it possible to cover any type of existing covering, such as for example a VSM type floor covering, without degrading its punching resistance performance, nor increasing the total thickness of the final covering too much so as not to have to cut the bottoms of doors.

[0015] Punching resistance means a residual indentation of less than 0.2 mm at 2.5 hours in the punching test carried out according to the ISO24343-1 standard of June 2007.

[0016] Another objective of the invention is to provide such a structure which is balanced and suitable for free installation and without coupling means, with satisfactory rigidity to withstand the passage of heavy loads, while having a surface mass of less than 3.5 kg / m 2 , preferably less than 3 kg / m 2 to facilitate logistics and reduce environmental impact.

[0017] For this purpose, a rollable multi-layer structure, based on PVC, has been developed for the production of a loose-lay floor covering, with a total thickness of between 1.4 mm and 2.5 mm, preferably between 1.4 and 2 mm, or even between 1.5 mm and 1.7 mm.

[0018] A thicker structure would require cutting the bottoms of the doors and would result in a heavy coating with the known disadvantages in terms of logistics and environmental impact.

[0019] The multi-layer structure includes, from top to bottom: - a wear layer, made of PVC which can be presented in several forms, namely a layer having a decoration throughout its thickness made from tinted and pressed PVC granules, by calendering, by extrusion, by coating and gelling of a layer of PVC plastisol tinted in the mass, or alternatively a transparent wear layer, for example made by coating and gelling of a PVC plastisol; the wear layer has a thickness greater than that of the prior art, between 0.3 and 1.2 mm to allow the U2S classification, or even U3, preferably U4 of the UPEC classification to be achieved; - a reinforcing frame, for example a glass grid, a glass veil or a complex comprising a grid and a glass veil; - a compact PVC backing layer, i.e. one which is not foamed, preferably calendered, pressed or extruded, for example coated, having a thickness greater than that of the prior art, between 0.3 and 1.3 mm and a surface mass between 360 and 2000 g / m 2 , for example 635 g / m 2 for 0.5 mm thickness, which can be increased to reduce the thickness.

[0020] In this way, the invention makes it possible to provide a rollable multi-layer structure allowing the creation of a loose-lay floor covering, which can have a wear layer with a decoration in its thickness and can be laid over an existing VSM-type covering, without degrading its punching resistance performance, and with a minimized environmental impact.

[0021] For areas larger than 30 m 2 , or even greater than 50 m 2, it may still be advisable to install this type of covering with double-sided adhesive on the edge of the surface to be covered.

[0022] The roll-up flooring is laid in strips. Depending on the desired level of traffic resistance, the strips can be heat-sealed edge to edge using conventional methods thanks to the minimum thickness of 0.3 mm of the wear layer, particularly when it has a decoration within its thickness.

[0023] The thickness of the coating of the invention is between 1.4 mm and 2.5 mm, preferably between 1.4 and 2 mm, or even between 1.5 mm and 1.7 mm, which makes it possible to cover an existing coating without having to cut the bottoms of the doors and to limit the weight of the multi-layer structure.

[0024] Furthermore, tests were carried out by the Applicant and the multi-layer structure of the invention allows, when it covers a VSM type coating, to maintain the punching resistance performance, or even to improve it since the results showed a residual indentation of less than 0.04 mm at 2.5 hours and less than 0.02 mm at 24 hours.

[0025] The rigidity of the multi-layer structure allows it to withstand heavy load traffic and to satisfy the castor chair test according to standard NF EN 425 in free installation, or even semi-free installation with the use of double-sided adhesive on the periphery and / or on the edges of the strips.

[0026] Preferably, the reinforcing frame is a glass veil comprising a higher surface mass than that of the prior art, between 60 and 100 g / m 2 , preferably between 70 and 80 g / m 2 , for example 75 g / m 2, impregnated on both sides. For example, the reinforcement is impregnated on its lower side with a bonding layer in the form of a gelled plastisol, such as a PVC plastisol, and on its upper side with a plastisol, such as a PVC plastisol, gelled and possibly printed with a decorative layer. With a surface mass greater than 100 g / m 2 the veil breaks when rolling and the hand, that is to say the feeling of the installer when laying, becomes too rigid.

[0027] Alternatively, the reinforcing frame is a glass grid, for example obtained from glass fiber yarns, preferably spaced from each other by between 1 mm and 6 mm, preferably between 3 mm and 5 mm, depending on the longitudinal and transverse dimensions. The yarns advantageously have a count of between 25 and 85 Tex, and preferably between 34 and 68 Tex. It is possible to use multi-strand yarns in order to modify the behavior of the grid obtained. For example, the warp yarns can be made up of two strands twisted together. The thickness of the glass grid is small, of the order of 0.1 -0.2 mm and it generally has a surface mass of between 30 g / m 2 and 70 g / m 2 , preferably between 50 and 60 g / m 2 In the multi-layer structure, the thickness of the glass grid is completely impregnated into the thickness of the wear and backing layers.

[0028] The reinforcing frame may also be a complex comprising a glass veil and a glass grid as described bonded together.

[0029] Preferably, the backing layer comprises 20 to 70 PCR (Parts Per Cent of PVC Resin) of plasticizer and a filler content of less than 5% by weight of the backing layer, or even zero filler content. Preferably, the backing layer comprises 20 to 50 PCR of plasticizer, more preferably 30 to 50 PCR. PCR means parts per hundred of resin. In this embodiment, the low filler content in the backing layer has another advantage in that the surface mass of this layer is low. In other words, the invention makes it possible to rebalance the structure, with a lower weight, compared to the solution consisting of increasing the thickness of the backing layer.

[0030] Alternatively, the backing layer comprises 20 to 70 PCR of plasticizer, preferably between 30 and 50 PCR and a filler rate of less than 130 PCR, preferably between 50 and 110 PCR. A filler rate greater than 110 PCR or even 130 PCR makes the structure too heavy to be easily transported. In this embodiment, the structure has better strength than a structure whose backing layer has less than 50 PCR while remaining easy to handle and without excessively degrading the total weight.

[0031] Regardless of the implementation method, the backing layer helps balance the structure, without requiring excessively increasing the thickness of the multi-layer structure.

[0032] In an embodiment aiming to limit the thickness of the multilayer structure, the backing layer has a thickness of between 0.3 and 0.7 mm, preferably between 0.4 and 0.6 mm, for example 0.5 mm, and a weight of between 360 and 840 g / m2 This embodiment is particularly advantageous when the backing layer comprises a filler rate of less than 5% by weight of the backing layer, or even a zero filler rate.

[0033] In another embodiment aimed at increasing the performance of resistance to punching and rolling of heavy loads, while maintaining a limited thickness of the multilayer structure, the backing layer has a thickness of between 0.7 mm and 1.3 mm, preferably between 0.9 and 1.1 mm, for example 0.5 mm, and a weight of between 840 g / m 2 and 2000 g / m 2 This embodiment is particularly advantageous when the backing layer comprises a filler rate of less than 130 PCR, preferably between 50 and 110 PCR.

[0034] According to a particular embodiment, the impregnated glass veil has a thickness of 0.8 mm, with a glass veil with a thickness of 0.2 mm.

[0035] In a particular embodiment, the wear layer comprises 20 to 70 PCR of plasticizer, preferably 20 to 50 PCR of plasticizer. For example, the wear layer is transparent and comprises 30 to 50 PCR of plasticizer, with a filler level of less than 5% by weight of the wear layer, or even a zero filler level, and the multilayer structure comprises a decor layer positioned under the wear layer.

[0036] In this configuration, the low charge rate in the plasticized PVC wear layer causes the phenomenon of "curving" or incurvation tending to unbalance the multi-layer structure, compensated by the backing layer, in particular when it has a charge rate of less than 5% by weight of the backing layer, or even a zero charge rate.

[0037] The wear layer is, for example, a layer of gelled PVC plastisol. Preferably, and in order to reduce the weight of the structure as much as possible, the wear layer, for example coated, has a thickness of between 0.3 and 0.5 mm while still achieving the U2S classification of the UPEC classification.

[0038] According to another embodiment, the wear layer may have a decoration throughout its thickness, for example in the form of a layer of pressed granules, the wear layer itself forming the decoration. The granules may be of any desired color, as is well known in the state of the art. In this alternative, it advantageously has a thickness of between 0.5 and 1.2 mm, preferably between 0.9 and 1.2 mm in order to guarantee better wear resistance and to achieve classification U3, preferably U4 of the UPEC classification.

[0039] The layer of pressed granules is obtained from plasticized and loaded PVC. Generally, the loading rate of the wear layer when it has a decoration throughout its thickness, and in particular when it is made with pressed granules, is much lower than 130 PCR, preferably lower than 100 PCR or even 80 PCR so as to have good scratch resistance. The layer of pressed granules thus tends to generate a phenomenon of "curving" or incurvation tending to unbalance the multi-layer structure, which is compensated by the backing layer. The wear layer when it has a decoration throughout its thickness generally has a minimum loading rate of 50 PCR.

[0040] Preferably, when the wear layer has a decoration throughout its thickness, in particular when it is made of pressed PVC granules, and to avoid curving effects, a ratio between the thickness of the wear layer and the thickness of the assembly comprising the reinforcement frame and the backing layer is between 0.45 and 0.55 or even equal to 0.5. In this way, the reinforcement frame reinforcement is centered in the structure. This ensures a good compromise between the total thickness of the multi-layer structure and its weight, while having a balanced structure.

[0041] Preferably, when the frame is an impregnated glass veil, and to ensure a good compromise between the total thickness of the multilayer structure and its weight, while having a balanced structure, a ratio between the thickness of the wear layer and the thickness of the assembly comprising the impregnated glass veil and the backing layer, is between 0.2 and 0.45. Since the impregnated glass veil has a non-negligible thickness, its position in the structure is important so as not to unbalance it.

[0042] In order to further reduce, or even avoid, the wave / swell phenomenon that is generated in front of the wheels of a heavy load, i.e. of the order of 200 kg or more, circulating on the multi-layer structure in free laying on a ground, the backing layer is preferably made by coating, calendering or extrusion, because these techniques make it possible to obtain a smoother contact surface with the ground than when the backing layer is made from pressed granules and then sanded. The face in contact with the ground of the backing layer is preferably not sanded.

[0043] According to another characteristic, the multilayer structure according to the invention preferably has a tensile modulus for 1% elongation of between 4 and 9 daN / cm. The tensile modulus for 1% elongation is for example measured according to method M.1 “determination of toughness” given by the QB 30 - M1 -Ueatc July 2015 reference of the CSTB. In other words, it is necessary to exert a traction of a force of between 4 and 9 daN / cm, on either side of a sample of the structure, to attempt to lengthen it by at least 1% of its length.

[0044] Above 9 daN / cm, an undesirable "drum" effect of the structure can be observed, which means that it does not relax flat on its own on a flat support after being unrolled from the mandrel used for its transport. On the contrary, below 4 daN / cm, the structure tends to be too flexible and to promote the phenomenon of waves in reaction to the traffic of heavy loads.

[0045] The tensile modulus for 1% elongation of the multilayer structure is preferably between 4 and 7 daN / cm to facilitate installation, the structure thus being more flexible. Alternatively, the tensile modulus for 1% elongation of the multi-layer structure is between 7 and 9 daN / cm, to increase resistance to heavy load traffic

[0046] Preferably, when the wear layer comprises a decoration throughout its thickness, that is to say when it is mass-dyed and produced by pressing, calendering, extrusion or coating, the ratio between the quantity of fillers in total weight of the wear layer and the quantity of fillers in total weight of the backing layer is between 0.85 and 1 and the ratio between the quantity of plasticizer in total weight of the wear layer and the quantity of plasticizer in total weight of the backing layer is between 0.85 and 1. This advantageous embodiment makes it possible to limit curving phenomena and to balance the multilayer structure by using similar compositions for these two layers.

[0047] Alternatively, the parts per cent of resin, fillers and plasticizers of the compositions of the wear layer and the backing layer differ by less than ten percent, preferably by less than five percent, more preferably are identical.

[0048] The invention also relates to an assembly comprising a multi-layer structure according to the aforementioned characteristics, laid, in particular loosely, on a vinyl-on-foam (VSM) type covering, i.e. comprising at least one layer of PVC bonded to a backing layer of foamed PVC. Brief description of the drawings

[0049] Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended figures in which:

[0050] [Fig.1] is a schematic sectional representation of one embodiment of the multi-layer structure of the invention, with a wear layer having a decoration throughout its thickness.

[0051] [Fig.2] is a schematic sectional representation of an embodiment of the multi-layer structure of the invention, with a decorative layer printed on a glass veil coated on both sides with a gelled PVC plastisol.

[0052] [Fig.3] is a view similar to that of Figure 2, with a glass veil and glass grid complex, impregnated on both sides with a gelled PVC plastisol. Detailed description of the invention

[0053] The invention relates to a multi-layer structure (1) for producing a loose-laying floor covering, and without coupling means between two adjacent structures, which is balanced with a low weight, i.e. less than 5 kg / m 2, while having a total thickness of less than 2.5 mm, and for example between 1.4 mm and 2 mm.

[0054] The multilayer structure (1) according to the invention can be wound on itself or on a mandrel to be presented in a roll.

[0055] For this purpose, the multi-layer structure (1) has a flexibility enabling it to comply with the ISO 24344:2008 standard. In this standard, flexibility is defined by the ability of a covering or a layer of a floor covering to be wrapped around a 20 mm mandrel, without cracks or crazing forming. Thus, the multi-layer structure according to the invention subjected to this test would not exhibit breaks, cracks, crazing and other permanent defects.

[0056] The multi-layer structure (1) according to the invention makes it possible to cover any type of existing covering, such as for example a VSM type floor covering, without degrading its punching resistance performance, nor increasing the total thickness of the final covering too much so as not to have to cut the bottoms of the doors.

[0057] With reference to Figure 1, the multi-layer structure (1) successively comprises, from the top to the ground, a wear layer (2) made of PVC having a thickness of between 0.3 and 1.2 mm, a reinforcing frame, for example a glass grid (7), a compact backing layer (4) made of PVC having a thickness of between 0.3 and 1.3 mm, and a surface mass of between 360 and 2000 g / m 2 .

[0058] The wear layer (2) provides slip control, wear resistance and ease of cleaning. It contains 20 to 70 PCR of plasticizer and has a pattern throughout its thickness. he

[0059] The wear layer (2) can be obtained by extrusion, by calendering, by pressing, or by coating then gelling a plastisol. The wear layer (2) can be coated with a varnish without departing from the scope of the invention, such as a varnish based on polyurethane or urethane acrylate. The wear layer (2) can be varnished and / or grained in order to improve resistance to stains and scratches.

[0060] The wear layer (2) provides the decorative function, in particular if it is obtained from a tinted plastisol or by pressing tinted granules.

[0061] The reinforcing frame is in the form of a glass grid (7), a glass veil (3) or a complex comprising a grid (7) and a glass veil (3). The glass grid (7) improves resistance to the passage of heavy loads and to punching. The glass grid (7) is permeable and allows direct thermal bonding of the wear layers (2) and backing layers (4) without the use of an additional layer or glue. The threads of the glass grid (7) are for example obtained from glass fibers, and are preferably spaced from each other by between 1 mm and 6 mm, preferably between 3 mm and 5 mm, depending on the longitudinal and transverse dimensions. The threads advantageously have a count of between 25 and 85 Tex, and preferably between 34 and 68 Tex. The thickness of the glass grid (7) is low, of the order of 0.1 -0.2 mm and a surface mass of between 30 g / m 2 and 70 g / m 2, preferably between 50 and 60 g / m 2 . In the multi-layer structure (1), the thickness of the glass grid is completely impregnated in the thickness of the wear (2) and back (4) layers. The tensile strength of a glass grid implemented in the invention is advantageously between 400 N / 50mm and 1000 N / 50mm in the longitudinal and transverse directions.

[0062] The wear layer (2) can be bonded to the backing layer (4) by pressing, lamination or gluing although a bond without an additional layer is preferred. The advantage of the glass grid (7) is to allow direct thermobonding of the layers (2, 4) through the meshes of the grid (7). Advantageously, the multilayer structure (1) consists only of a wear layer (2) possibly varnished, a glass grid (7) and a backing layer (4).

[0063] With reference to Figure 2 and according to an alternative embodiment of the invention, the multilayer structure (1) successively comprises, from the top towards the ground, a wear layer (2) made of PVC, a glass veil (3) comprising a surface mass between 60 and 100 g / m 2 , and impregnated on both sides with a compact PVC backing layer (4).

[0064] In this configuration, the wear layer (2) is transparent or translucent so that a decorative layer is visible through the wear layer (2).

[0065] In this configuration, the wear layer (2) comprises 30 to 50 PCR of plasticizer, and a zero filler rate, or even less than 5% by weight of the wear layer (2).

[0066] The glass veil (3) comprises glass fibers of approximately 10 pm diameter and 10 mm length, randomly distributed and bound together by a modified polyvinyl alcohol.

[0067] The tensile strength of a reinforcing web is generally chosen to be between 100 N / 50mm and 400 N / 50mm in the longitudinal and transverse directions, measured according to the ISO 1924 / 2 method.

[0068] The glass veil (3) makes it possible to improve the dimensional stability of the multilayer structure (1) as well as the resistance to punching. The multi-touch structure according to the invention can claim class U2S.

[0069] The glass veil (3) is for example impregnated on its lower face with a bonding layer (6) in the form of a gelled plastisol, such as a PVC plastisol, and on its upper face with a plastisol (5), such as a PVC plastisol, gelled and printed with a decorative layer (not shown).

[0070] To improve resistance to the passage of heavy loads and punching, the glass veil (3) can form a complex with a glass grid (7), the complex then being impregnated on both sides.

[0071] With reference to Figure 3, in the same way as for the glass veil alone, the glass veil (3) / glass grid (7) complex is for example impregnated on its lower face with a bonding layer (6) in the form of a gelled plastisol, such as a PVC plastisol, and on its upper face with a plastisol (5), such as a PVC plastisol, gelled and printed with a decorative layer. The glass grid (7) is permeable and allows the impregnation layer to also impregnate the glass veil (3).

[0072] In order to bond the glass veil (3) with the glass grid (7) without complicating the manufacturing process or unduly weighing down the structure, the binder comprises an acrylic glue, or ethylene-vinyl acetate ("EVA"), or plastisol such as a PVC plastisol. Preferably the binder is arranged in a thin layer, at a density of between 5 and 35 g / m 2 , or preferably between 10 g / m 2 at 30 g / m2 .

[0073] This configuration also makes it possible to improve the dimensional stability of the multilayer structure (1) as well as the resistance to punching. The multi-touch structure according to the invention can claim the U2SP3 or even U4P3 classification according to the UPEC classification.

[0074] Whatever the embodiment, the backing layer (4) is made of compact plasticized polyvinyl chloride, i.e. which is not foamed.

[0075] The backing layer (4) is calendered, pressed, or extruded. Generally, a calendered backing layer (4) is preferred because it is easier to integrate recycled material into its composition with this manufacturing technique, without degrading the decor or the appearance of the multilayer structure (1). In addition, the face in contact with the ground of a calendered layer is smoother and presents fewer mechanical constraints due to the manufacturing process than a pressed and sanded layer.

[0076] The backing layer (4) preferably comprises 20 to 70 PCR of plasticizer and a filler rate of less than 5% by weight of the backing layer, or even a zero filler rate. Preferably, the backing layer comprises 20 to 50 PCR of plasticizer, more preferably 30 to 50 PCR.

[0077] Alternatively, the backing layer comprises 20 to 70 PCR of plasticizer, preferably between 30 and 50 PCR and a filler rate of less than 130 PCR, preferably between 50 and 110 PCR. A filler rate greater than 110 PCR or even 130 PCR makes the structure too heavy to be easily transported. In this embodiment, the structure has better strength while remaining easy to handle.

[0078] The backing layer (4) can be related to the wear layer (2), in terms of composition and properties, and therefore allows the structure to be balanced by counterbalancing the curvature phenomenon generated by the wear layer (2), with a low weight. Preferably, the wear layer (2) and the backing layer (4) are obtained from a gelled PVC plastisol and have the same plasticizer level.

[0079] Preferably, when the wear layer (2) comprises a decoration throughout its thickness, i.e. when it is mass-dyed and produced by pressing, calendering, extrusion or coating, the ratio between the quantity of fillers in total weight of the wear layer (2) and the quantity of fillers in total weight of the backing layer (4) is between 0.85 and 1 and the ratio between the quantity of plasticizer in total weight of the wear layer (2) and the quantity of plasticizer in total weight of the backing layer (4) is between 0.85 and 1. This advantageous embodiment makes it possible to limit curving phenomena and to balance the multilayer structure.

[0080] The fillers used in each of the layers of the structure may be calcium carbonate, clay, silica, kaolin, or talc. It is preferably a powdered material to prevent the filler from degrading during mixing of the PVC masterbatch intended to constitute the layers, but fibers may be considered. The fillers can be used alone or in a mixture.

[0081] To ensure a good compromise between the total thickness of the multi-layer structure (1) and its weight, while having a balanced structure, a ratio between the thickness of the wear layer (2) and the thickness of the assembly comprising the impregnated glass veil (3) and the backing layer (4), is between 0.2 and 0.45, for example 0.27 or 0.33.

[0082] Preferably, when the wear layer (2) has a decoration throughout its thickness, in particular when it is made of pressed PVC granules, a ratio between the thickness of the wear layer (2) and the thickness of the assembly comprising the reinforcing frame (3, 7) and the backing layer (4), is between 0.45 and 0.55 or even equal to 0.5. In this way, the reinforcing frame is centered in the multilayer structure (1). This makes it possible to ensure a good compromise between the total thickness of the multilayer structure (1) and its weight, while having a balanced structure.

[0083] Tests were carried out by the Applicant on a multi-layer structure (1) according to figure 1 placed without glue on a concrete support and presenting; - a total thickness of 2 mm and a surface mass of 3100 g / m 2 : - a wear layer of pressed PVC granules with a thickness of 1 mm and a surface mass of 1550 g / m2 , comprising 41 PCR of plasticizer (DINCH), 100 PCR of filler (calcium carbonate) and less than 2 PCR of pigment and process aids; - a 34 tex glass grid with a surface mass of 55 g / m 2 ; - a compact PVC backing layer made by calendering, with a thickness of 1 mm, and a surface mass of 1550 g / m 2 comprising 41 PCR of plasticizer (DINCH), 100 PCR of filler (calcium carbonate) and less than 2 PCR of pigment and process aids.

[0084] Several manufacturing processes for the structure (1) are possible. For the purposes of the test, the wear layers (2) and backing layers (4) are produced independently and then hot-rolled by pressing the assembly with the glass grid (7) using a static press to form the multi-layer structure (1).

[0085] An alternative is to form the backing layer (4) by calendering, heat-rolling the glass grid, sprinkling PVC granules onto the backing layer (4) and then heat-pressing the granules onto the assembly formed by the glass grid (7) and backing layer (4) to form the wear layer (2) and the multi-layer structure (1).

[0086] Another alternative is to form the backing layer (4) by calendering, laminate the glass grid (7) onto the backing layer (4) to bond them, form a wear layer (2) from PVC granules by hot pressing and then hot laminate it onto the glass grid (7) and backing layer (4) assembly to form the multi-layer structure (1).

[0087] The tests carried out on the set showed: - a residual indentation of less than 0.03 mm at 2.5 hours and less than 0.01 mm at 24 hours, in accordance with the P3 classification of the UPEC classification; - dimensional stability after 6 hours at 80°C of -0.04% in the machine and cross directions; - a curvature after 6 hours at 80°C of 0.26 mm; - a modulus at 1% elongation of 6.19;

[0088] Furthermore, the Applicant also noted that when a heavy load of around 200 kg (100 kg hospital bed with a weight of 100 kg) passes over the structure, this does not generate any waves in front of the wheels.

[0089] The tested multi-layer structure has excellent mechanical characteristics while being easy to install and easy to handle.

[0090] Tests were carried out by the Applicant on an assembly comprising a VSM type covering covered, in loose laying, with a multi-layer structure (1) according to figure 2 showing; - a total thickness of 1.6 mm: - a wear layer of gelled PVC plastisol with a thickness of 0.3 mm and a surface mass of 350 g / m 2 ; - a glass veil comprising a surface mass of between 75 g / m 2 , impregnated on its lower face with a gelled PVC plastisol, and on its upper face with a gelled PVC plastisol printed with a decorative layer; the impregnated veil having a thickness of 0.8 mm; - a compact backing layer of gelled PVC plastisol, free of filler, having a thickness of 0.5 mm, and a surface mass of 585 g / m 2 .

[0091] Tests carried out on this set showed a residual indentation of less than 0.04 mm at 2.5 hours and less than 0.02 mm at 24 hours.

[0092] Furthermore, the Applicant also noted that when a heavy load of around 200 kg (100 kg hospital bed with a weight of 100 kg) passes over the structure, this does not generate any waves in front of the wheels.

[0093] The values ​​quoted in the description are values ​​measured according to the following standards: Total thickness: NF EN ISO 24346 April 2012 Layer thicknesses: NF EN ISO 24340 April 2012 Weight / Surface mass: ISO 23997 December 2007 Modulus at 1% elongation: QB 30 - M1 -Ueatc July 2015 Residual static punching (Building): ISO 24343-1 June 2007 Dimensional stability: NF EN ISO 23999 August 2018 Curvature after 6 hours at 80°C; NF EN ISO 23999 August 2018

[0094] It is clear from the above that the invention does indeed provide a multi-layer structure (1) which allows free installation and in particular the covering of a VSM type floor covering, without degrading its punching resistance performance, nor excessively increasing the total thickness of the final covering so as not to have to cut the bottoms of doors.

[0095] Furthermore, the multi-layer structure according to the invention is balanced and suitable for free installation without coupling means, with satisfactory rigidity to withstand the passage of heavy loads, while having a mass of less than 3.5 kg / m 2 to facilitate logistics and reduce environmental impact.)

Claims

Claims 1. Rollable multi-layer structure (1), based on PVC, for the production of a loose-lay floor covering, comprising a total thickness of between 1.4 mm and 2.5 mm characterized in that eWe comprises: - a wear layer (2) made of PVC having a thickness of between 0.3 and 1.2 mm; - a reinforcing frame (3.7); - a compact PVC backing layer (4) having a thickness of between 0.3 and 1.3 mm, and a surface mass of between 360 and 2000 g / m 2 .

2. Rollable multilayer structure (1) according to claim 1, characterized in that the reinforcing frame is a glass veil (3) comprising a surface mass of between 60 and 100 g / m 2 , impregnated on both sides.

3. Rollable multilayer structure (1) according to claim 2, characterized in that the glass veil is impregnated on its lower face with a bonding layer in the form of a gelled plastisol, such as a PVC plastisol, and on its upper face with a plastisol, such as a PVC plastisol, gelled and optionally printed with a decorative layer.

4. Rollable multi-layer structure (1) according to claim 1, characterized in that the reinforcing frame is a glass grid (7).

5. Rollable multilayer structure (1) according to one of the preceding claims, characterized in that the backing layer (4) comprises 20 to 70 PCR of plasticizer and a filler rate of less than 5% by weight of the backing layer, or even a zero filler rate.

6. Rollable multilayer structure (1) according to one of the preceding claims, characterized in that the backing layer (4) comprises 20 to 70 PCR of plasticizer, preferably between 30 and 50 PCR and a filler rate of less than 130 PCR, preferably between 50 and 110 PCR.

7. Rollable multi-layer structure (1) according to one of the preceding claims, characterized in that the wear layer comprises 20 to 70 PCR of plasticizer, preferably 20 to 50 PCR of plasticizer.

8. Rollable multi-layer structure (1) according to one of the preceding claims, characterized in that the wear layer (2) is transparent, comprises 30 to 50 PCR of plasticizer, and a filler rate of less than 5% by weight of the wear layer (2), or even a zero filler rate, and in that the multi-layer structure (1) comprises a decorative layer positioned under the wear layer (2).

9. Rollable multi-layer structure (1) according to one of the preceding, characterized in that the wear layer (2) has a decoration throughout its thickness, for example made from pressed PVC granules.

10. Rollable multi-layer structure (1) according to claim 9, characterized in that the ratio between the quantity of fillers in total weight of the wear layer (2) and the quantity of fillers in total weight of the backing layer (4) is between 0.85 and 1 and the ratio between the quantity of plasticizer in total weight of the wear layer (2) and the quantity of plasticizer in total weight of the backing layer (4) is between 0.85 and 1.

11. Assembly comprising a multi-layer structure (1) according to one of the preceding claims, placed on a vinyl-type covering on foam, that is to say comprising at least one layer of PVC bonded to a backing layer of foamed PVC]

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