Repositionable acoustic floor covering

Abstract

The invention relates to a multilayer structure for producing a floor covering in tile or plank form comprising successively, from top to bottom: - an upper wear layer; - a middle layer; - an acoustic backing layer; the upper, middle and acoustic backing layers being bonded together and made from polymeric materials, the acoustic backing layer comprising a backing face, which is intended to be laid on the floor and is covered with a pressure-sensitive adhesive having a 90 degree peel resistance of between 0.6 and 4 daN / cm.

Description

Description Title of the invention: Repositionable acoustic floor covering technical field

[0001] The invention relates to the technical field of tile or plank floor coverings made from polymeric materials such as PVC.

[0002] More particularly, the invention relates to the field of tile or plank floor coverings comprising an acoustic backing layer whose underside is covered with a pressure-sensitive adhesive, which can be installed on site without the addition of glue and in a repositionable manner.

[0003] Repositionable floor coverings are generally self-adhesive. They offer numerous advantages, including ease of installation. Their underside, which is in contact with the floor, is coated with an adhesive, eliminating the tedious task of spreading glue on the floor. When it comes to removal at the end of the product's lifespan, they are also preferable to permanent adhesives.

[0004] Document US2006156663A1 describes, for example, a slab comprising a decorative surface layer, an acoustic layer and a repositionable adhesive layer allowing adjustment of the slab's position during the installation operation.

[0005] The presence of a compressible acoustic backing layer can, however, reduce the initial adhesion of the repositionable adhesive by diminishing the pressure applied by the installer when placing the tile. This can lead to undesirable movement of the tiles or planks.

[0006] The applicant's document FR3057801 describes the use of a pressure-sensitive adhesive for installing repositionable flooring in rolls or tiles, which prevents the transfer of plasticizers that may come from the floor being covered.

[0007] However, none of these solutions allows for a tile or plank floor covering that includes an acoustic backing layer and provides both good support, repositionable installation and good resistance to expansion, particularly in the event of strong temperature variations in the room.

[0008] This phenomenon can indeed lead to tiles detaching, swelling, and gaps appearing between the edges of the planks, and is therefore undesirable. This is usually avoided by not using repositionable flooring in areas subject to significant temperature variations, such as behind a bay window. For these areas, a solution is to use traditional glued-down flooring installed with an acrylic-based adhesive. Description of the invention

[0009] One of the aims of the invention is to overcome the disadvantages of the prior art, in particular by proposing a repositionable tile or plank floor covering made from polymeric materials, comprising an acoustic backing layer, resistant to traffic and having improved initial adhesion.

[0010] Another objective of the invention is to improve the resistance to expansion and the resistance to traffic over time of repositionable tile or plank floor coverings.

[0011] An additional objective is to improve resistance to large temperature variations in the room.

[0012] Another objective of the invention is to facilitate the manufacture, transport and on-site implementation of repositionable tile or plank floor coverings.

[0013] Another objective of the invention is to overcome the problems of resistance to puncture, sound absorption properties and traffic resistance of repositionable tile or plank floor coverings by proposing improved acoustic middle and backing layers.

[0014] An additional objective is to counter the problems associated with installing repositionable tile or plank flooring in high-traffic areas or areas subject to heavy loads, by offering repositionable tile or plank flooring that includes means of joining tiles or planks or is compatible with additional means of joining tiles or planks.

[0015] To this end, a multi-layer structure has been developed for the production of tile or plank flooring, the multi-layer structure comprising successively, from top to bottom: - a top wear layer; - a middle layer; - an acoustic backing layer; the top, middle and acoustic back layers being bonded together and made from polymeric materials, the acoustic back layer comprising a back face, intended to be laid on the floor, and covered with a pressure-sensitive adhesive having a peel resistance at 90° between 0.6 and 4 daN / cm.

[0016] The resulting flooring is self-adhesive, allowing for loose-lay installation without the need for additional adhesive between the flooring and the subfloor. It is repositionable, meaning it can be installed or removed without damaging the subfloor. This flooring can be adjusted multiple times during installation and later removed for a change of flooring. The pressure-sensitive adhesive, with a peel strength at 90° between 0.6 and 4 daN / cm², provides a good balance between initial adhesion, when the installer applies standard force, and repositionability if the flooring is not installed correctly and needs to be repositioned.Below a peel strength of 0.6 daN / cm, and due to the compressibility of the acoustic layer, the initial adhesion is too weak for the floor to be walked on immediately after installation or to prevent accidental displacement during the installation of adjacent tiles or planks. The installer would need to use a roller weighing several tens of kilograms to ensure sufficient adhesion of the multi-layer structure. A peel strength at 90° exceeding 4 daN / cm prevents the installer from repositioning the flooring without risking damage to the substrate or the acoustic backing.

[0017] Polymeric materials used to create the top and / or middle layers include thermoplastic polymers such as PVC, polyurethane, polypropylene, polyethylene, and polyethylene terephthalate. Alternatively, the top and / or middle layers can each be obtained from a layer of linoleum.

[0018] The acoustic backing layer is foamed, preferably to form a closed-cell foam layer. It can advantageously be made from extruded foamed polystyrene or cross-linked foamed polyethylene.

[0019] Advantageously, pressure-sensitive adhesives have a shear strength between 2 and 10 MPa, preferably between 4 and 6 MPa. The adhesive's shear strength determines its ability to withstand stresses in the coating's application plane. Below 2 MPa, the shear strength is insufficient to ensure good resistance to long-term traffic stresses, while a shear strength above 10 MPa degrades the coating's repositionability and its ability to be easily removed at the end of its service life without using a mechanical stripper or damaging the substrate. Therefore, a shear strength between 2 and 10 MPa provides a compromise between traffic resistance and ease of removal. With a shear strength of 4 to 6 MPa for repositionable adhesives, both of these factors are optimized.

[0020] In an advantageous embodiment, the pressure-sensitive adhesive is made from block copolymer selected from styrene-isoprene or styrene-butadiene diblocks or styrene-isoprene-styrene or styrene-butadiene-styrene triblocks.

[0021] The pressure-sensitive adhesive based on block copolymer, chosen from styrene-isoprene or styrene-butadiene diblocks or styrene-isoprene-styrene or styrene-butadiene-styrene triblocks, exhibits very good initial adhesion and cohesion on an acoustic backing layer. This type of thermoplastic adhesive improves resistance to expansion by limiting the loss of adhesive strength when the room temperature rises. This allows the panels or boards to be held in position and limits their expansion and the formation of bulges, while maintaining elasticity compatible with application on an acoustic backing layer, particularly one made from cross-linked foamed polyethylene. The styrene-isoprene-styrene terpolymer is preferred because it further improves the adhesive's thermal stability, making it more suitable for installations in rooms subject to significant temperature variations.This terpolymer also exhibits good adhesion and cohesion on foamed acoustic backing layers made of cross-linked polyethylene.

[0022] The invention therefore makes it possible to obtain a multilayer structure exhibiting better resistance to temperature variations and therefore better mechanical resistance to traffic over time.

[0023] Preferably, the pressure-sensitive adhesive is covered with a thermoplastic anti-stick film, preferably made of polyethylene terephthalate.

[0024] More specifically, the invention relates to a repositionable multilayer structure covered with a pressure-sensitive adhesive (PSA) applied using a hot-melt PSA adhesive. The PSA can be hot-deposited onto the acoustic backing layer and then cooled.

[0025] Alternatively, the PSA adhesive is deposited on the thermoplastic anti-adhesive film and then the whole is hot laminated onto the acoustic backing layer, keeping the thermoplastic anti-adhesive film as support and as protection for transport.

[0026] After cooling the pressure-sensitive adhesive, it exhibits greater affinity and cohesion on the acoustic backing layer, which allows the thermoplastic anti-adhesive film to be removed during installation without the adhesive leaving residues on the film, particularly when the film is made of polyethylene terephthalate.

[0027] The thermoplastic non-stick film also offers an advantage when manufacturing the multi-layer structure.

[0028] Conventional manufacturing processes for repositionable tiles or planks first involve a step of producing the tile or plank in a ready-to-install format; the tile or plank is then coated with a pressure-sensitive adhesive which is covered and protected by silicone-coated kraft paper.

[0029] To avoid adhesive overlap problems and given the difficulties in positioning the kraft paper, it always has a greater width than the back face of the acoustic layer, which is a problem when the installer tries to pre-position tiles edge to edge.

[0030] According to the invention, the tiles or planks can be produced by cutting a larger format, in sheets or rolls, from a multilayer structure comprising successively a top wear layer, a middle layer, and an acoustic backing layer according to the invention, all bonded together. The acoustic backing layer is covered on its underside with a pressure-sensitive adhesive according to the invention, the adhesive itself being covered with a thermoplastic release film. The multilayer structure can thus be produced continuously or sheet by sheet, including with the release film already bonded, and then tiles or planks are cut to the desired installation format to achieve the desired result.

[0031] The slabs or planks generally have a rectangular or square shape, with a length between 0.6 and 2 meters, preferably between 0.6 and 1.2 meters and a width between 0.1 and 1 meter, preferably between 0.2 and 0.8 meters.

[0032] The slabs or planks generally have a surface mass of between 2 and 8 kg / m³ 2 , preferably between 3 and 6 kg / m 2 .

[0033] Preferably, the multilayer structure has a surface mass between 4.5 and 8 kg / m³ 2 The pressure-sensitive adhesive exhibits a 90° peel strength between 0.6 and 1.9 daN / cm. An increased surface mass effectively reduces the 90° peel strength required for good adhesion.

[0034] Preferably, the multilayer structure has a surface mass between 2 and 4.4 kg / m³ 2The pressure-sensitive adhesive exhibits a 90° peel strength of between 2 and 4 daN / cm. A reduced surface mass necessitates an increased 90° peel strength to achieve better adhesion.

[0035] The advantage of a thermoplastic non-stick film, unlike a classic kraft paper film, is that it can be cut at the same time as the rest of the structure.

[0036] Advantageously, the edges of the non-stick film extend beyond at least one edge of the reverse face by a length less than or equal to 1 mm, or do not extend beyond and are contiguous with the edges of the acoustic reverse layer.

[0037] A thermoplastic non-stick polyethylene terephthalate film allows for a particularly clean cutting operation of the edges of the multilayer structure with conventional sawing, continuous machining or punching tools.

[0038] To improve dimensional stability and resistance to temperature variations within the room, the middle layer includes at least one reinforcing element, for example, a glass grid, a glass veil, or a composite of a grid and a glass veil. When the reinforcing element is a glass veil, it typically has a surface mass of between 100 g / m² 2 and 400 g / m 2 , preferably between 300 and 380 g / m 2 to achieve very good dimensional stability.

[0039] Preferably, the middle layer has a thickness between 0.5 and 3 mm, more preferably between 1 and 2 mm. These thicknesses allow the multilayer structure to withstand sufficient puncture and traffic, with the thickness adapted to the requirements of the premises for which the multilayer structure is intended. The middle layer can be made from PVC, for example, plasticized and filled PVC.

[0040] The fillers used in each layer of the structure can be calcium carbonate, clay, silica, kaolin, or talc. Preferably, a powdered material is used to prevent degradation of the filler during the mixing of the PVC masterbatch used to form the layers, but fibers can also be used. The fillers can be used alone or in mixtures.

[0041] Advantageously and in order to facilitate manufacturing and recycling operations, the top and middle layers are made from PVC, for example unfilled plasticized PVC for the top layer and filled plasticized PVC for the middle layer.

[0042] Preferably, the top wear layer has a thickness of between 0.3 and 2 mm, preferably between 0.5 and 1 mm.

[0043] Preferably, the acoustic backing layer has a thickness between 0.5 and 3 mm, more preferably between 1 and 2 mm. This thickness allows the multilayer structure to improve the sound absorption of the multilayer structure and can be adapted according to the expected absorption level.

[0044] Advantageously, the acoustic backing layer is a closed-cell foam layer, as this type of layer optimizes the balance between the thickness of the acoustic layer and its sound absorption level. Preferably, the acoustic backing layer is made from irradiation- or chemically cross-linked foamed polyethylene. Irradiation cross-linking is preferred because it provides more uniform cross-linking.

[0045] Advantageously, and to improve strength under heavy traffic, the multilayer structure according to the invention comprises four edges, two of which include male coupling means and two opposite edges include complementary female coupling means. These male / female coupling means allow for horizontal, vertical, or inclined assembly and advantageously ensure locking in the vertical and / or horizontal direction of two multilayer structures according to the invention assembled together.

[0046] Advantageously, the multilayer slab or plank structure comprises a base layer and a surface layer placed on top of the base layer and visible after the slab or plank is installed. The slab or plank has an overlap edge where the surface layer cantilevers over the base layer, and a support edge opposite the overlap edge where the surface layer is recessed to expose the base layer. The cantilevered base layer partially covers an adjacent slab or plank, thus concealing any gaps between two adjacent slabs caused by unevenness or shrinkage, resulting in an improved visual appearance.

[0047] Advantageously, and to improve durability under heavy traffic, the multilayer structure according to the invention comprises at least one groove which is either: - made in the acoustic layer on the reverse side and opening onto the reverse face, or; - made on one of the edges of the multilayer structure, and opening onto a side wall of the multilayer structure; said groove being suitable for receiving an edge-to-edge positioning device for at least two multilayer structures.

[0048] This type of edge-to-edge positioning device is described for example in the Applicant's applications FR3128478 or FR3147821, the content of which is incorporated by reference.

[0049] The invention also relates to a floor covering comprising two multilayer structures including at least one groove as described above and positioned edge to edge by a positioning device. Brief description of the drawings

[0050] [Fig.1] is a cross-sectional view of the multilayer structure according to the invention.

[0051] [Fig.2] is a cross-sectional view of an alternative embodiment of the multilayer structure according to the invention.

[0052] [Fig.3] is a cross-sectional view of an alternative embodiment of the multilayer structure according to the invention having at least one groove formed in the acoustic reverse layer and opening onto the reverse face, said groove being suitable for receiving an edge-to-edge positioning device for at least two multilayer structures.

[0053] [Fig.4] is a cross-sectional view of an alternative embodiment of the multilayer structure according to the invention having at least one groove formed on one of the edges of the multilayer structure and opening onto a lateral wall of the multilayer structure, said groove being suitable for receiving an edge-to-edge positioning device for at least two multilayer structures.

[0054] [Fig.5] is a cross-sectional view of two multilayer structures according to figure 4 linked together by an edge-to-edge positioning device of at least two multilayer structures.

[0055] [Fig.6] is a top view and partial section of an alternative embodiment of the multilayer structure according to the invention having two edges comprising male coupling means and two opposite edges comprising complementary female coupling means.

[0056] [Fig.7] is a top view and partial section of another alternative embodiment of the multilayer structure according to the invention having two edges comprising male coupling means and two opposite edges comprising complementary female coupling means.

[0057] [Fig.8] is a diagram illustrating the results of example 2. Detailed description of the invention

[0058] The multilayer structure (1) according to the invention can have any form, in particular in panel, slab or blade.

[0059] Referring to Figure 1, the multilayer structure (1) comprises, successively from top to bottom, a top wear layer (2), a middle layer (3), and an acoustic backing layer (4) covered with a pressure-sensitive adhesive (5). The top (2), middle (3), and acoustic backing (4) layers are bonded together and made of polymeric materials. The acoustic backing layer (4) includes a backing face (4a), intended to be laid on the floor, and covered with a pressure-sensitive adhesive (5) having a peel strength at 90° of between 0.6 and 4 daN / cm.

[0060] The 90° peel resistance test measures the adhesion of an adhesive floor covering to a fiber cement substrate when subjected to peel forces at 90° according to a method adapted from the NF EN ISO 22631:2019 standard.

[0061] To perform a 90° peel strength test according to a method based on standard NF EN ISO 22631:2019, fifteen multilayer structural specimens for a floor covering measuring 250 x 50 mm were produced. The 250 mm length corresponds to the manufacturing direction of the covering. The surfaces of the samples with the pressure-sensitive adhesive were bonded to 150 x 50 mm fiber cement boards, so that one end of the floor covering to be tested coincided with the end of the bonded board, resulting in a bonded surface of 120 mm x 50 mm, thus leaving a 130 mm portion of the sample unbonded. Immediately after positioning the coating under test, the specimen was passed through the 60 mm wide, 90 mm diameter roller, with a total mass of 3.50 kg according to NF EN ISO 22631:2019, making it go back and forth along the length of the specimen, without applying any additional pressure.

[0062] A first set of five test tubes is stored for 24 hours at 23°C and 50% relative humidity before measurement. A second set of five test tubes is stored for 3 days at 70°C and 50% relative humidity, then stored for 24 hours at 23°C before measurement. A third set of five test tubes is stored for 14 days at 50°C and 50% relative humidity, then stored for 24 hours at 23°C before measurement.

[0063] A tensile testing machine, for example a Lloyd type, instrument reference LR5K, using a 90° peel device with two rollers, is employed. The fiber cement substrate is in a horizontal position during the test, with the tensile testing machine pulling the sample vertically upwards at a speed of 100 mm / min. The 90° peel strength is expressed in daN / cm and corresponds to the average force in daN measured from a 20 mm peel of the sample from the substrate up to 80 mm peel, normalized to the width of the sample.

[0064] According to the invention, the pressure-sensitive adhesive (5) having a peel resistance at 90° of between 0.6 and 4 daN / cm according to the method described allows a good compromise between the initial adhesion of the coating, when the installer applies a conventional force to the coating, and repositionability if the coating has not been laid in the right place and needs to be moved.

[0065] Polymeric materials used to make the top (2) and / or middle (3) layers include, for example, thermoplastic polymers such as PVC, polyurethane, polypropylene, polyethylene, polyethylene terephthalate. Alternatively, the top (2) and / or middle (3) layers can each be obtained from a layer of linoleum.

[0066] The top layer (2) of wear provides control of slip resistance, wear resistance, and ease of cleaning. It generally has a thickness of between 0.3 and 2 mm, preferably between 0.5 and 1 mm. When made from PVC, it typically includes 20 to 50 PCR plasticizers.

[0067] The upper wear layer (2) can be obtained by extrusion, calendering, pressing, or by coating and then gelling a PVC plastisol.

[0068] The upper wear layer (2) can also serve as a decorative layer, especially if it is obtained from a dyed plastisol or by pressing dyed granules, for example obtained from plasticized and dyed PVC granules.

[0069] The middle layer (3) can be obtained by extrusion, calendering, pressing, or by coating and then gelling a plastisol; although calendering, extrusion, and pressing provide better resistance to expansion. The middle layer (3) is preferably made from plasticized and filled PVC. The middle layer (3) generally has a thickness of between 0.5 and 3 mm, more preferably between 1 and 2 mm.

[0070] The upper wear layer (2) and middle layer (3) can be made from one or more layers bonded together without departing from the scope of the invention.

[0071] The acoustic backing layer (4) is foamed, preferably to form a closed-cell foam layer. It can advantageously be made from extruded foamed polystyrene or cross-linked foamed polyethylene. The acoustic backing layer (4) is generally between 0.5 and 3 mm thick, more preferably between 1 and 2 mm.

[0072] The upper wear layer (2), middle layer (3) and acoustic back layer (4) can be bonded by any means such as thermolamination and / or via a bonding layer of glue, plastisol or double-sided adhesive film.

[0073] Advantageously, the pressure-sensitive adhesive (5) is in the form of a layer with a surface mass between 25 and 60 g / m 2in order to present a compromise between initial adhesion and ease of application of the adhesive. Preferably the pressure-sensitive adhesive (5) has a surface mass between 30 and 50 g / m 2 in order to achieve better cohesion during installation.

[0074] Advantageously, the pressure-sensitive adhesive (5) has a shear strength between 2 and 10 MPa, preferably between 4 and 6 MPa. According to the invention, a shear strength between 2 and 10 MPa provides a compromise between traffic resistance and ease of removal. With a shear strength of 4 to 6 MPa for the repositionable adhesive, these two factors are optimized.

[0075] The shear strength test measures the adhesion of a bonded or adhesive-bonded floor covering to a substrate when subjected to shear forces. The method is based on the standard NF EN ISO 22632:2019. Shear strength is given in MPa.

[0076] To implement the method from standard NF EN ISO 22632:2019, fifteen multilayer structural test specimens for a floor covering measuring 250 x 50 mm (the 250 mm length corresponding to the manufacturing direction of the covering) were prepared. The surfaces of the specimens with the pressure-sensitive adhesive were bonded to 150 x 50 mm fiber cement boards, resulting in a bonded surface of 50 mm x 50 mm, thus leaving a 200 mm portion of the specimen unbonded. Immediately after positioning the floor covering under test, the specimen was passed over a 60 mm wide, 90 mm diameter roller with a total mass of 3.50 kg, as per NF EN ISO 22632:2019, making a single back-and-forth pass along the length of the specimen without applying any additional pressure.

[0077] A first set of five test tubes is stored for 24 hours at 23°C and 50% relative humidity before measurement. A second set of five test tubes is stored for 3 days at 70°C and 50% relative humidity, then stored for 24 hours at 23°C before measurement. A third set of five test tubes is stored for 14 days at 50°C and 50% relative humidity, then stored for 24 hours at 23°C before measurement.

[0078] A tensile testing machine, for example a Lloyd type, instrument reference LR5K, is used. The ends of the specimen are held in the appropriate jaws of the tensile testing machine using shims to maintain the specimen's axis vertically and in line with the vertical movement of the jaws. The tensile testing machine pulls the specimen vertically upwards at a speed of (50 ± 2) mm / min, exceeding that of standard NF EN ISO 22632:2019.

[0079] Shear strength, expressed in newtons per square millimeter or in megapascals, corresponds to the maximum shear force in newtons during adhesive detachment, divided by the coverage area, expressed in square millimeters.

[0080] Regardless of the embodiment, the upper wear layer (2) may be coated with a varnish (11) without departing from the scope of the invention, such as a polyurethane or urethane acrylate-based varnish. The upper wear layer (2) may be varnished and / or textured to improve stain and scratch resistance.

[0081] In one embodiment and with reference to Figure 2, the upper wear layer (2) is transparent or translucent so that a decorative layer (12) is visible through the upper wear layer (2).

[0082] When the top wear layer (2) is made of PVC and is transparent, it generally comprises 30 to 50 PCR of plasticizer and a filler content of zero or less than 5% by weight of the top wear layer (2). The decorative layer (12) can be printed on the underside of the top wear layer (2) or on a polymer film (13) such as a PVC film. According to an alternative (not shown), the decorative layer (12) can be printed on an upper surface coated with a reinforcing mesh. The decorative layer (12) can be printed using any known technique such as digital printing.

[0083] According to the embodiment shown in Figure 2, the middle layer may include a reinforcing mesh (15). The reinforcing mesh (15) may be a glass grid or a glass fiber veil.

[0084] In order to combine the advantages of the different existing solutions, the reinforcing frame (15) may include a glass veil, which is complexed with a glass grid by means of a binder, preferably by lamination.

[0085] When the reinforcing mesh (15) is a glass veil, it generally has a surface mass of between 100 g / m 2 and 400 g / m 2 , preferably between 300 and 380 g / m 2 .

[0086] In this embodiment of Figure 2, the middle layer (3) is made from two intermediate middle layers (14a, 14b), the reinforcing reinforcement (15) being positioned and tied between the intermediate middle layers (14a, 14b).

[0087] The upper wear layers (2) the polymer film (13) presenting the decorative layer (12), the intermediate middle layers (14a, 14b) and the reinforcing reinforcement (15) are for example bonded by thermolamination, namely by a hot pressing operation, static or continuous.

[0088] The acoustic back layer (4) is linked to the middle layer (3) via a bonding layer (16), for example a layer of “HOTMELT ®” or two-component adhesive.

[0089] Advantageously, and according to Figures 3, 4 and 5, the multilayer structure (1) according to the invention comprises at least one groove (40, 41) which is either: - formed in the acoustic layer on the reverse side (4) and opening onto the reverse face (4a) or; - formed on one of the edges of the multilayer structure (1), and opening onto a lateral wall of the multilayer structure; said groove being suitable for receiving an edge-to-edge positioning device for at least two multilayer structures (50,51).

[0090] This type of edge-to-edge positioning device is described for example in the Applicant's applications FR3128478 or FR3147821, the content of which is incorporated by reference.

[0091] When the groove (40) is made in the acoustic reverse layer (4) and opening onto the reverse face (4a), it is preferably also made in the thickness of the middle layer (3).

[0092] When the groove (41) is formed on one of the edges of the multilayer structure (1), and opening onto a lateral wall of the multilayer structure, it is preferably formed mostly in the thickness of the middle layer (3).

[0093] Figure 3 shows a device (50) for edge-to-edge positioning of at least two multilayer structures (1). The device ensures horizontal and vertical blocking of two multilayer structures (1).

[0094] Figure 5 illustrates a cross-sectional view of two multilayer structures (1, 1') according to Figure 4 linked together by a device (51) for edge-to-edge positioning of at least two multilayer structures (1, 1'). The device ensures horizontal and vertical locking of the two structures (1, 1').

[0095] In an advantageous embodiment, not shown, the multilayer structure (1) according to the invention comprises both a groove (40) formed in the acoustic back layer (4) and opening onto the back face (4a), and a groove (41) formed on one of the edges of the multilayer structure (1) and opening onto a lateral wall of the multilayer structure (1), said grooves being adapted to receive an edge-to-edge positioning device for at least two multilayer structures. Such a device is, for example, described in patent application EP1119671.

[0096] Advantageously, and according to Figures 6 and 7, the multilayer structure (1) according to the invention comprises four edges, two of which include male coupling means (60, 70) and two opposite edges include complementary female coupling means (61, 71). These male (60, 70) / female (61, 71) coupling means allow for horizontal, vertical, or tilted assembly and advantageously ensure vertical and / or horizontal locking of two multilayer structures (1, 1') according to the invention assembled together.

[0097] Such male (60,70) / female (61,71) coupling means are generally machined mainly within the thickness of the middle layer (3). Such male (60,70) / female (61,71) coupling means are described, for example, in documents GB2256023, EP 1026341, WO2012 / 004701, or in documents FR3024990 and WO 2016 / 030627 of the Applicant, the content of which is incorporated by reference.

[0098] Example 1: A multilayer structure (1) is produced for the creation of a tile floor covering according to the invention, incorporating the embodiment shown in Figure 2, comprising successively: - a layer of (11) polyurethane varnish of 10g / m 2 ; - a calendered top layer (2) made from plasticized PVC, 0.4mm thick and 500 g / m 2 ; - a 0.07 mm thick PVC film (13) printed with a decorative layer (12); - a middle layer (3) made from plasticized and filled PVC and comprising a first intermediate middle layer (14a) calendered 0.63 mm thick and 1270 g / m 2 , a glass veil (15) coated with a 0.2 mm thick, 350 g / m² gelled PVC plastisol 2surface mass and a second layer, an intermediate median (14b) calendered, made from plasticized and filled PVC, 0.6 mm thick and 1210 g / m 2 - a bonding layer (16), namely a two-component adhesive of 90g / m 2 ; - a backing acoustic layer (4) made of closed-cell, irradiation-crosslinked foamed polyethylene, with a thickness of 1 mm per 100 g / m 2 ; - a pressure-sensitive adhesive made from a styrene-isoprene-styrene triblock with a deposited surface mass of 38 g / m 2 ; ■ an anti-stick film (6) of polyethylene terephthalate with a thickness of 0.05 mm and of 70g / m2 covers the pressure sensitive adhesive (5) to protect it. The top layer (2), the printed film (13), and the layers of the middle layer (14a, 14b) are thermally bonded. The pressure-sensitive adhesive (5), made from a styrene-isoprene-styrene triblock, is first hot-applied to the polyethylene terephthalate (PSA) release film (6) using a rubber or EVA roller. The assembly, consisting of the release film and the still-hot PSA, is then pressed against the back face (4a) of the acoustic backing layer (4). After the PSA cools, it retains a strong affinity and excellent cohesion with the acoustic backing layer (4) but exhibits much weaker adhesion to the release film. Therefore, during use, the release film can be removed without any cohesive breakdown of the adhesive (5) and without leaving any adhesive residue on the release film (6).

[0099] The resulting multilayer structure forming a floor covering (1) has a thickness of 3.5mm and a surface mass of 4678g / m 2 .

[0100] 90° peel and shear tests are performed according to the protocols shown on the coating in Example 1

[0101]

[0102] The resulting flooring exhibits excellent installation characteristics: it is not overly adhesive, allowing for repositioning, while simultaneously maintaining good initial adhesion. Furthermore, aging tests show that this adhesion increases over time without becoming excessive, facilitating removal without damaging the substrate. Finally, temperature variations do not excessively increase or decrease its peel strength or shear resistance. The invention guarantees both the tile's stability in place and limits its expansion.

[0103] Example 2: Expansion test in a chamber

[0104] To highlight the invention's ability to limit thermal expansion, a comparative test was conducted in a thermal chamber. Expansion measurements were performed using DEWESOFT® software. A reference REF blade, 1230 mm long by 200 mm wide, was bonded to a fiber cement substrate at room temperature and then incubated for 72 hours at 23°C and 50% relative humidity after bonding. Strain sensors were attached to each end of the blade to measure length variations as a function of temperature changes within the chamber. The test began at 13°C, and the temperature was then increased to 45°C. The elongation (expansion) of the blade was measured between 13°C and 45°C.The reference blade uses the same layers as the blade according to example 1 of the invention except that the PSA adhesive is replaced by a conventional acrylic adhesive, for example a reference acrylic glue "LVT 4" from the manufacturer "SADER", applied with the notched spatula.

[0105] A second blade of the same dimensions and incorporating the same layers as the blade according to example 1, including the PSA adhesive according to the invention, is placed under the same conditions and monitored during the same protocol.

[0106] Figure 8 shows the expansion of the planks along their length. As an example, an expansion test for a plank installed according to Example 1, but without any adhesive, shows a lengthwise expansion of 1.2 mm at 45°C. The expansion measured according to Example 1 is close to that of the REF reference plank, which offers excellent bonding using a permanent acrylic adhesive but does not allow for removal of the flooring at the end of its lifespan without damaging the substrate.

[0107] The expansion performance according to Example 1 is also significantly better than the acceptability threshold, which aims to limit longitudinal expansion to 0.15 mm for this blade length. The PSA adhesive according to the invention therefore provides excellent blade retention.

Claims

Demands 1. Multilayer structure (1) for the production of a tile or plank floor covering, the multilayer structure (1) comprises successively, from top to bottom: - a top layer (2) of wear; - a median layer (3); - an acoustic backing layer (4); the upper (2), middle (3) and acoustic back (4) layers being bonded together and made from polymeric materials, characterized in that the acoustic back layer (4) comprises a back face (4a), intended to be placed on the floor, and covered with a pressure-sensitive adhesive (5) having a peel resistance at 90° between 0.6 and 4 daN / cm.

2. Multilayer structure (1) according to claim 1, characterized in that the pressure-sensitive adhesive (5) has a shear strength between 2 and 10 MPa, preferably between 4 and 6 MPa.

3. Multilayer structure (1) according to any one of the preceding claims, characterized in that the pressure-sensitive adhesive (5) is made from block copolymer selected from styrene-isoprene or styrene-butadiene diblocks or styrene-isoprene-styrene or styrene-butadiene-styrene triblocks.

4. Multilayer structure (1) according to any one of the preceding claims, characterized in that the pressure-sensitive adhesive (5) is covered with a thermoplastic anti-stick film (6), preferably a polyethylene terephthalate film.

5. Multilayer structure (1) according to claim 4, characterized in that the non-stick film (6) extends beyond at least one edge of the reverse face (4a) by a length less than or equal to 1 mm.

6. Multilayer structure (1) according to any one of the preceding claims, characterized in that the middle layer (3) comprises at least one reinforcing reinforcement (15).

7. Multilayer structure (1) according to any one of the preceding claims, characterized in that the middle layer (3) has a thickness of between 0.5 and 3 mm, preferably between 1 and 2 mm.

8. Multilayer structure (1) according to any one of the preceding claims, characterized in that the acoustic back layer (4) has a thickness of between 0.5 and 3 mm, preferably between 1 and 2 mm.

9. Multilayer structure (1) according to any one of the preceding claims, characterized in that the acoustic back layer (4) is a closed-cell foam layer, preferably made from cross-linked polyethylene.

10. Multilayer structure (1) according to any one of the preceding claims, characterized in that the upper (2) and middle (3) layers are made from PVC.

11. Multilayer structure (1) according to any one of the preceding claims, characterized in that it comprises four edges, of which two edges include male coupling means (60,70), and two opposite edges include complementary female coupling means (61,71).

12. Multilayer structure (1) according to any one of the preceding claims, characterized in that it comprises at least one groove (40,41): - formed in the acoustic layer on the reverse side (4) and opening onto the reverse face (4a), or; - formed on one of the edges of the multilayer structure (1), and opening onto a lateral wall of the multilayer structure (1); said groove (40,41) being suitable for receiving a device (50, 51) for edge-to-edge positioning of at least two multilayer structures (1,1').

13. Floor covering comprising two multilayer structures (1,1') according to claim 12 characterized in that the two multilayer structures (1,1') are positioned edge to edge by a positioning device (50, 51).

Images