Repositionable acoustic flooring

Abstract

The invention relates to a multilayer structure for producing a tile or plank floor covering comprising, successively from top to bottom: - a top wear layer; - a middle layer; - an acoustic backing layer; the top, middle, and acoustic backing layers being bonded together and made from polymeric materials, the acoustic backing layer comprising a back face, intended to be laid on the floor, and covered with a pressure-sensitive adhesive having a peel strength at 90° of between 0.6 and 4 daN / cm. Figure for the abstract: Fig. 1

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 laid 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. Indeed, their underside, which is in contact with the floor, is coated with an adhesive, eliminating the tedious task of spreading glue on the floor. At the end of the product's lifespan, they are also preferable to so-called permanent adhesives when it comes to removal.

[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, degrade the initial adhesion of the repositionable adhesive by reducing the pressure applied by the installer to position 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 laying repositionable flooring in rolls or tiles and allowing the prevention of transfers of plasticizers that may come from the covered floor.

[0007] However, none of these solutions makes it possible to obtain a tile or plank floor covering, comprising an acoustic backing layer and allowing 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 the appearance of tiles detaching, swelling, and gaps between the edges of the planks, and is therefore undesirable. This phenomenon is usually avoided by not using repositionable flooring in areas subject to significant temperature variations, for example, behind a bay window. For these areas, one solution is to use conventional glued-down floor coverings 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 variations in room temperature.

[0012] Another objective of the invention is to facilitate the manufacture, transport and implementation on site 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 the installation of repositionable tile or plank flooring in high-traffic areas, or areas subject to heavy loads, by offering repositionable tile or plank flooring comprising means for assembling tiles or planks or compatible with additional means for assembling tiles or planks.

[0015] To this end, a multilayer structure has been developed for producing a tile or plank floor covering, the multilayer 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 floor covering is self-adhesive, allowing for loose-lay installation without the need for additional adhesive between the floor covering and the subfloor. It is repositionable, meaning it can be installed or removed without damaging the substrate. This floor covering can be adjusted repeatedly during installation and subsequently removed to change the floor covering. The pressure-sensitive adhesive, with a peel strength at 90° between 0.6 and 4 daN / cm², provides a good compromise between initial adhesion and strength. The peel strength of the flooring depends on the installer's ability to apply standard force and its repositionability if it 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 suitable for producing the top and / or middle layers include, for example, 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 so as to form a closed-cell foam layer. It can advantageously be made from extruded foamed polystyrene or cross-linked foamed polyethylene.

[0019] Advantageously, the pressure-sensitive adhesive has a shear strength of between 2 and 10 MPa, preferably between 4 and 6 MPa. The adhesive's shear strength determines, in particular, its ability to withstand stresses in the coating's application plane. Below 2 MPa, the shear strength is insufficient to ensure good resistance to traffic stresses over time, 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. Thus, a shear strength between 2 and 10 MPa provides a compromise between traffic resistance and ease of removal. With a shear strength of the repositionable adhesive between 4 and 6 MPa, these two 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 a block copolymer selected from styrene-isoprene or styrene-butadiene diblocks or styrene-isoprene-styrene or styrene-butadiene-styrene triblocks exhibits very good initial adhesion and good cohesion on an acoustic backing layer. This type of thermoplastic adhesive notably improves resistance to expansion by limiting the loss of strength The adhesive bonds better when the room temperature rises. This helps to hold the tiles or planks 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. Styrene-isoprene-styrene terpolymer is preferred because it further improves the thermal stability of the adhesive, making it more suitable for installation in rooms subject to significant temperature variations. This terpolymer also exhibits good adhesion and cohesion on cross-linked polyethylene foamed acoustic backing layers.

[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 assembly is hot laminated onto the acoustic backing layer, keeping the thermoplastic anti-adhesive film as a 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 anti-stick film also has an advantage when manufacturing the multilayer structure.

[0028] Conventional manufacturing processes for repositionable tiles or blades include first a step of producing the tile or blade in the format ready to be installed, the tile or blade is then coated with a pressure-sensitive adhesive which is covered and protected by silicone-coated kraft paper.

[0029] To avoid adhesive coverage 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 slabs or blades can be made from a cutting operation of a larger format, in sheet or roll form, of a structure The multilayer structure comprises 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 liner. The multilayer structure can thus be produced continuously or panel by panel, including with the release liner already bonded. Tiles or planks are then cut to the desired installation format to achieve the desired result.

[0031] 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.

[0032] Thus 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.

[0033] 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.

[0034] To improve dimensional stability and resistance to temperature variations in the part, the middle layer includes at least one reinforcing element, for example, a glass grid, a glass veil, or a composite comprising a grid and a glass veil. When the reinforcing element is a glass veil, it generally has a surface mass between 100 g / m² and 400 g / m², preferably between 300 and 380 g / m² to obtain very good dimensional stability.

[0035] Preferably, the middle layer has a thickness of 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, the thickness being 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.

[0036] The fillers used in each layer of the structure may be calcium carbonate, clay, silica, kaolin, or talc. Preferably, the material should be in powder form to prevent degradation of the filler during the mixing of the PVC masterbatch used to form the layers, but the use of fibers may also be considered. The fillers may be used alone or in mixtures.

[0037] Advantageously, and in order to facilitate manufacturing and recycling operations, the upper and middle layers are made from PVC, for example PVC unfilled plasticized for the top layer and plasticized and filled PVC for the middle layer.

[0038] Preferably, the upper wear layer has a thickness of between 0.3 and 2 mm, preferably between 0.5 and 1 mm.

[0039] Preferably, the acoustic backing layer has a thickness of 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.

[0040] Advantageously, the acoustic backing layer is a closed-cell foam layer because this type of layer optimizes the trade-off between the thickness of the acoustic layer and its sound absorption level. More 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.

[0041] 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 tilted assembly and advantageously ensure locking in the vertical and / or horizontal direction of two multilayer structures according to the invention assembled together.

[0042] Advantageously, and to improve performance in case of heavy traffic, the multilayer structure according to the invention includes at least one groove which is either: - formed in the acoustic reverse layer and opening onto the reverse face, or; - formed 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.

[0043] This type of edge-to-edge positioning device is described for example in the Applicant's applications FR3128478 or FR3147821.

[0044] 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

[0045] [Fig.1] is a cross-sectional view of the multilayer structure according to the invention.

[0046] [Fig.2] is a cross-sectional view of an alternative embodiment of the structure multilayer according to the invention.

[0047] [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.

[0048] [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.

[0049] [Fig.5] is a cross-sectional view of two multilayer structures according to [Fig.4] linked together by an edge-to-edge positioning device of at least two multilayer structures.

[0050] [Fig.6] is a top view and partial sectional view 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.

[0051] [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.

[0052] [Fig.8] is a diagram illustrating the results of example 2. Detailed description of the invention

[0053] The multilayer structure (1) according to the invention can have any shape, in particular in panel, slab or blade form.

[0054] With reference to [Fig. 1], the multilayer structure (1) comprises, successively from top to bottom, an upper wear layer (2), a middle layer (3), and an acoustic backing layer (4) covered with a pressure-sensitive adhesive (5). The upper (2), middle (3), and acoustic backing (4) layers are bonded together and made of polymeric materials. The acoustic backing layer (4) comprises 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.

[0055] The 90° peel resistance test allows the adhesion of an adhesive floor covering to a fiber cement substrate to be measured when subjected to peel forces at 90° according to a method adapted from the standard NF EN ISO 22631:2019.

[0056] To perform a 90° peel strength test according to a method derived from standard NF EN ISO 22631:2019, fifteen multilayer structural specimens for the production of a floor covering measuring 250 x 50 mm, the 250 mm length corresponding to the manufacturing direction of the covering, are produced. The faces of the samples bearing the pressure-sensitive adhesive are glued onto 150 x 50 mm fiber cement boards, such that one end of the floor covering to be tested coincides with the end of the glued board, thus obtaining a glued surface of 120 mm x 50 mm, leaving a 130 mm portion of the sample unglued. 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.

[0057] A first batch of five test tubes is stored for 24 hours at 23°C and 50% relative humidity before measurement. A second batch 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 batch 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.

[0058] A tensile testing machine, for example a Lloyd type, instrument referenced LR5K, using a 90° peel device equipped with two rollers, is employed. The fiber cement substrate is in a horizontal position during the test, the tensile testing machine pulling the sample vertically upwards at a speed of 100 mm / min. The 90° peel resistance 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.

[0059] 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 placed in the right place and needs to be moved.

[0060] The polymeric materials used to produce the top (2) and / or middle (3) layers are, for example, thermoplastic polymers such as PVC, polyurethane, polypropylene, polyethylene, and polyethylene terephthalate. Alternatively, the top (2) and / or middle (3) layers can each be obtained from a layer of linoleum.

[0061] The top wear layer (2) provides 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 generally comprises 20 to 50 PCRs of plasticizers.

[0062] The upper wear layer (2) can be obtained by extrusion, calendering, pressing, or by coating and then gelling a PVC plastisol.

[0063] The upper wear layer (2) can also serve as a decorative layer, in particular if it is obtained from a dyed plastisol or by pressing dyed granules, for example obtained from plasticized and dyed PVC granules.

[0064] 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.

[0065] 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.

[0066] The acoustic backing layer (4) is foamed, preferably so as 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) generally has a thickness of between 0.5 and 3 mm, more preferably between 1 and 2 mm.

[0067] 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.

[0068] Advantageously, the pressure-sensitive adhesive (5) is in the form of a layer with a surface mass of between 25 and 60 g / m² to provide a compromise between initial adhesion and ease of application. Preferably, the pressure-sensitive adhesive (5) has a surface mass of between 30 and 50 g / m² to obtain better cohesion during application.

[0069] Advantageously, the pressure-sensitive adhesive (5) has a shear strength of between 2 and 10 MPa, preferably between 4 and 6 MPa. According to the invention, a shear strength of between 2 and 10 MPa provides a compromise between traffic resistance and ease of removal. With a shear strength of the repositionable adhesive of between 4 and 6 MPa, these two factors are optimized.

[0070] 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 standard NF EN ISO 22632:2019. Shear strength is given in MPa.

[0071] To implement the method from standard NF EN ISO 22632:2019, fifteen multilayer structural test specimens for the production of a floor covering, measuring 250 x 50 mm (the 250 mm length corresponding to the manufacturing direction of the covering), are prepared. The faces of the specimens with the pressure-sensitive adhesive are bonded to 150 x 50 mm fiber cement boards, so as to obtain a bonded surface of 50 mm x 50 mm, thus leaving a 200 mm portion of the specimen free. Immediately after positioning the floor covering under test, the specimen is passed over a 60 mm wide, 90 mm diameter roller with a total mass of 3.50 kg, according to NF EN ISO 22632:2019, making a back-and-forth pass along the length of the specimen without applying any additional pressure.

[0072] A first batch of five test tubes is stored for 24 hours at 23°C and 50% relative humidity before measurement. A second batch 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 batch 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.

[0073] A tensile testing machine, for example a Lloyd type, instrument referenced LR5K, is used. The ends of the specimen are held in the appropriate jaws of the tensile testing machine using wedges to maintain the axis of the specimen vertically and in line with the direction of the vertical movement of the jaws. The tensile testing machine pulls the specimen vertically upwards at a speed of (50 + / - 2) mm / min, which is higher than that of standard NF EN ISO 22632:2019.

[0074] The shear strength, expressed in newtons per square millimeter or in megapascals, corresponds to the maximum shear force in newtons during the peeling of the adhesive, divided by the coverage area, expressed in square millimeters.

[0075] 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.

[0076] In one embodiment and with reference to [Fig.2], the upper wear layer (2) is transparent or translucent so that a decorative layer (12) is visible through the upper wear layer (2).

[0077] When the top wear layer (2) is made of PVC and is transparent, it generally comprises 30 to 50% of plasticizer, and a filler content of zero or even less than 5% by weight of the top wear layer (2). The decorative layer (12) can be printed on an underside of the top layer. (2) wear or on a polymer film (13) such as a PVC film. According to an alternative not shown, the decorative layer (12) may be printed on a top surface coated with a reinforcing armature. The decorative layer (12) may be printed by any known technique such as digital printing.

[0078] According to the embodiment of [Fig. 2], the middle layer may include a reinforcing mesh (15). The reinforcing mesh (15) may be a glass grid or a glass fiber veil.

[0079] 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.

[0080] When the reinforcing structure (15) is a glass veil, it generally has a surface mass between 100 g / m2 and 400 g / m2, preferably between 300 and 380 g / m2.

[0081] In this embodiment of [Fig.2], the middle layer (3) is made from two intermediate middle layers (14a, 14b), the reinforcing reinforcement (15) being positioned and linked between the intermediate middle layers (14a, 14b).

[0082] The upper wear layers (2), the polymer film (13) having 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.

[0083] 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.

[0084] 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).

[0085] This type of edge-to-edge positioning device is described for example in the Applicant's applications FR3128478 or FR3147821.

[0086] 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).

[0087] 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).

[0088] Fig. 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).

[0089] 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').

[0090] 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 side 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 EPI 119671.

[0091] 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 locking in the vertical and / or horizontal direction of two multilayer structures (1, 1') according to the invention assembled together.

[0092] Such male (60,70) / female (61,71) coupling means are generally machined mainly in 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.

[0093] Example 1:

[0094] A multilayer structure (1) is produced for the creation of a tile floor covering according to the invention, incorporating the embodiment of [Fig. 2], comprising successively: - a layer of (11) polyurethane varnish of 10g / m2; - a top layer (2) of calendered wear made from plasticized PVC, 0.4mm thick and 500 g / m2; - a PVC film (13) 0.07 mm thick 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 1270g / m2, a glass veil (15) coated with a gelled PVC plastisol 0.2 mm thick and 350 g / m2 surface mass and a second intermediate middle layer (14b) calendered made from plasticized and filled PVC 0.6 mm thick and 1210g / m2; - a bonding layer (16), namely a two-component adhesive of 90g / m2; - an acoustic backing layer (4) made of closed-cell, irradiation-crosslinked foamed polyethylene, with a thickness of 1mm for 100g / m2; - a pressure-sensitive adhesive made from styrene-isoprene-styrene triblock with a deposited surface mass of 38 g / m2; 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.

[0095] 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) backing film (6) using a rubber or EVA roller. The assembly formed by the backing film and the still-hot PSA is then pressed against the reverse side (4a) of the acoustic backing layer (4). After the PSA cools, it retains a strong affinity and very good cohesion with the acoustic backing layer (4) and much weaker adhesion to the backing film. Therefore, during use, the film can be removed without any cohesive breakdown of the adhesive (5) and without leaving any adhesive residue on the backing film (6).

[0096] The multilayer structure forming a floor covering (1) obtained has a thickness of 3.5mm and a surface mass of 4678g / m2.

[0097] 90° peel and shear tests are carried out according to the protocols presented on the coating of Example 1.

[0098] [Tables 1] Peel test at 90°: 1 day 23SC daN / cm 1.8; 3 days 70°C 2.7; 14 days 50°C 2.1. Shear strength test: 1 day 23°C MPa 5.4; 3 days 70°C 5.6; 14 days 50°C 5.6.

[0099] The resulting floor covering exhibits good installation characteristics, namely that 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, thus facilitating removal without damaging the substrate. Finally, temperature variations do not excessively increase or decrease the peel strength or shear resistance. The invention guarantees both the stability of the tile in place and also limits its expansion.

[0100] Example 2: Expansion test in a chamber

[0101] To highlight the invention's advantage in limiting thermal expansion, a comparative test in a thermal chamber is performed. Expansion measurements are taken using the "DEWESOFT®" software. A reference REF blade, 1230 mm long by 200 mm wide, is 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 are attached to each end of the blade to measure the length variations as a function of temperature changes in the chamber. The test begins at 13°C, the temperature is then increased to 45°C, and the elongation (expansion) of the blade is 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 adhesive “LVT 4” from the manufacturer “SADER”, applied with a notched spatula.

[0102] 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.

[0103] Figure 8 shows the expansion of the length of the planks. As an example, an expansion test for a plank according to Example 1, but installed without any adhesive, shows, according to the same test at 45°C, an expansion of 1.2 mm in its length. The expansion measured according to Example 1 is close to that of reference REF, which demonstrates excellent bonding using a permanent acrylic adhesive but does not allow for removal of the flooring at the end of its service life without damaging the substrate.

[0104] The expansion performance according to Example 1 is also much 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: - an upper wear layer (2); - a middle layer (3); - an acoustic backing layer (4); the upper (2), middle (3) and acoustic backing (4) layers being bonded together and made from polymeric materials, characterized in that the acoustic backing layer (4) comprises a back face (4a), intended to be laid on the floor, and covered with a pressure-sensitive adhesive (5) having a peel resistance at 90° of 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 reverse layer (4) and opening onto the reverse face (4a), or; - formed on one of the edges of the multilayer structure (1), and opening onto a side 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).

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