Multilayer structure for forming reinforced and recyclable floor covering

Abstract

The invention relates to a multilayer structure (1) for forming a floor covering, comprising at least one surface layer (2) adhered to a backing layer (3b), both the surface layer (2) and the backing layer (3b) being made of PVC. The multilayer structure (1) comprises, in order from top to bottom between the surface layer (2) and the backing layer (3b), a first woven reinforcement (5a), an intermediate layer (3a), a second woven reinforcement (5b), all of which are bonded to each other, to the surface layer (2) and to the backing layer (3b) by an adhesive layer (6) in the form of a hot melt film such as a copolyamide or copolyester or crosslinked polyurethane adhesive layer. The surface quality of the multilayer structure (1) is 2000 to 3000 g / m < 2 >. The intermediate layer (3a) and the backing layer (3b) are made of PVC and each comprise:-a thickness of 100 [mu] m to 200 [mu] m; -5 to 25 phr of a plasticizer, preferably 6 to 15 phr of a plasticizer.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible floor coverings, preferably in the form of rolls or welded-bonded kits.

[0002] The present invention relates to a multilayer structure for forming a reinforced and recyclable floor covering.

[0003] The invention has advantageous application, for example, in covering honeycomb aircraft floor panels. Background Art

[0004] It is well known in the prior art to use a multilayer structure for producing floor coverings comprising a surface layer bonded to a backing layer, known as a "laminate" backing layer, for example for covering aircraft floors.

[0005] In this type of construction, the laminate backing layer consists of a woven glass fiber reinforcement impregnated with a phenolic or polyester resin. This backing layer ensures the adhesion of the floor covering to its support, provides dimensional stability, prevents the migration of plasticizers from the PVC surface layer, improves impact resistance, and reduces the phenomenon of "telegraphing", i.e. the transmission of substrate irregularities to the floor covering. Another important aspect of floor coverings for aircraft floors is their ability to resist deformation of the floor during flight, which can lead to warping.

[0006] Laminated backing layers are complex to manufacture and require technical expertise that only a few companies possess, resulting in high production costs.

[0007] Another disadvantage of this laminate backing layer is that it is not recyclable due to the use of phenolic resin. Currently, this type of layer is usually shredded and discarded.

[0008] Documents US2010 / 0227132 and EP3064347 describe multilayer structures for forming floor coverings, wherein the backing layer comprises a composite material comprising woven or non-woven reinforcing fibers and a thermosetting or thermoplastic polymer resin selected from the group consisting of polyester resins, phenolic resins, epoxy resins, polysulfones, vinyl ester resins, epoxy-acrylic resins and mixtures thereof.

[0009] A resulting disadvantage is that the use of thermosetting resins affects the recyclability of the floor covering.

[0010] Replacing phenolic resins with thermoplastic resins also affects recyclability because the structure becomes too inhomogeneous. In addition, the expected properties of multilayer structures (such as weldability or traffic resistance between two structures) are not achieved. Summary of the invention

[0011] One of the objects of the present invention is to overcome the disadvantages of the prior art by proposing a multilayer structure, for example for covering aircraft floors, having a backing layer which is less expensive to produce than the laminate layer and which provides a multilayer structure which is fully satisfactory in terms of adhesion of the floor covering to its support, dimensional stability and impact resistance.

[0012] Another object of the present invention is to provide such a multilayer structure which has improved recyclability and limited weight.

[0013] Another object of the present invention is to provide such a multilayer structure having comparable or better resistance to telegraphing and warping than existing solutions.

[0014] For this purpose, a multilayer structure for forming a floor covering has been developed, comprising at least one surface layer bonded to a backing layer, both the surface layer and the backing layer being made of PVC.

[0015] According to the invention, the multilayer structure comprises, from top to bottom, between the surface layer and the backing layer, a first woven reinforcement, an intermediate layer and a second woven reinforcement, which are all bonded to each other, to the surface layer and to the backing layer by an adhesive layer in the form of a hot melt film (e.g., a copolyamide or copolyester, or a cross-linked polyurethane adhesive layer). The surface mass of the multilayer structure is 2000 to 3000 g / m 2 , the middle layer and the backing layer are made of PVC, and each comprises:

[0016] - thickness of 100 μm to 200 μm;

[0017] - 5 to 25 parts per hundred parts of resin (phr) of plasticizer, preferably 6 to 15 phr of plasticizer.

[0018] The braided reinforcement increases the rigidity and dimensional stability of the multilayer structure.

[0019] Since plasticizers are flammable compounds, the amount of plasticizer is directly related to the amount of flame retardant required in the composition. For example, limiting the amount of plasticizer to between 5 and 25 phr reduces the amount of flame retardant required or even eliminates the need for flame retardants, limits the migration of plasticizers into the double-sided adhesives commonly used to bond multilayer structures to honeycomb aircraft floors, and thus prevents the adhesion properties of these adhesives from degrading over time. The amount of plasticizer in the intermediate layer and the backing layer is 6 to 15 phr, providing a better compromise between the rigidity of the structure, the weight and the ease of installation.

[0020] Thus, the multilayer structure according to the invention having an intermediate layer and a backing layer provides a floor covering which is relatively inexpensive to manufacture and which is fully satisfactory in terms of adhesion to its support, dimensional stability, thermal bending and impact resistance. Since the surface layer, the intermediate layer and the backing layer are all made of PVC, the recyclability of the multilayer structure becomes feasible.

[0021] Preferably, the backing layer and / or the intermediate layer are made of PVC and have a flexural strength of 0.3 to 1.5 mN.m measured according to ISO 2493-2, in order to limit the print-through effect and to provide sufficient rigidity to the structure.

[0022] According to a particular embodiment, the surface layer comprises a top layer, in particular a wear-resistant layer, and one or more interlayers made of plasticized PVC.

[0023] For example, the top layer is transparent, and the first interlayer is placed directly below the surface layer, and can take the form of a patterned film. In this case, an opaque second interlayer is preferably placed below the printed film to ensure sufficient opacity.

[0024] The surface layer, interlayer, intermediate layer and backing layer are preferably made by calendaring, pressing, coating or extrusion to form a relatively smooth layer having a uniform composition throughout its thickness.

[0025] According to a specific embodiment, the first and / or second braided reinforcements may be impregnated with a thermoplastic or thermosetting polymer in an amount of 1% to 10% by weight of each impregnated braided reinforcement to maintain recyclability. This provides greater rigidity to the multilayer structure. The thermoplastic or thermosetting polymer may be selected from the group consisting of polyurethane resins, polyester resins, phenolic resins, epoxy resins, polysulfones, vinyl ester resins, epoxy-acrylic resins, and mixtures thereof.

[0026] Preferably, in order to improve the resistance to the "print-through" phenomenon known to those skilled in the art, the foam layer (preferably made of PVC) is bonded to the lower surface of the backing layer via an adhesive layer in the form of a cross-linked polyurethane (PUR) layer, a thermoplastic copolyester (CoPES) layer, a copolyamide or a thermoplastic polyurethane (TPU) layer.

[0027] The foam layer advantageously has a density of 0.15 to 0.25, preferably 0.20 to 0.25, and a thickness of 1.5 to 3 mm, preferably 1.9 to 2.5 mm, in order to provide good anti-printing properties without reducing the indentation resistance of the multilayer structure.

[0028] Advantageously, the foam layer comprises a third reinforcement at least partially impregnated in its thickness to improve the resistance of the foam layer and the overall multilayer structure. The third reinforcement at least partially impregnated in the thickness of the foam layer can be a non-woven fabric layer (preferably a glass fiber or polyester mesh), a reinforcing grid (preferably a glass fiber or polyester grid), or a composite material comprising a non-woven fabric layer bonded to a reinforcing grid.

[0029] Advantageously, the foam layer comprises a fourth reinforcement at least partially impregnated in its thickness to improve the anti-print-through properties of the overall multilayer structure. The fourth reinforcement at least partially impregnated in the thickness of the foam layer may be a non-woven fabric layer, preferably a glass fiber or polyester mesh, or a composite material comprising a non-woven fabric layer bonded to a reinforcing grid, preferably a glass fiber or polyester mesh. The fourth reinforcement advantageously has a lower surface intended to be bonded to a support such as an aircraft floor. Alternatively, the fourth reinforcement advantageously has a lower surface bonded to a double-sided adhesive to bond the multilayer structure to a support such as an aircraft floor.

[0030] Advantageously, in order to facilitate the installation of the multilayer structure according to the invention, the multilayer structure comprises, on the lower surface intended to come into contact with the floor (i.e. directly on the lower surface of the backing layer), a repositionable adhesive layer, which adheres better to the multilayer structure than to the floor, so as to allow the multilayer structure to be peeled off and repositioned. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] [ Figure 1 ] shows a cross-sectional view of a multilayer structure according to a first embodiment of the present invention, comprising a top layer, an interlayer, a first woven reinforcement, an intermediate layer, a second woven reinforcement and a backing layer.

[0032] [ Figure 2 ] is similar to Figure 1 view of the building, which has two mezzanines.

[0033] [ Figure 3 ] is similar to Figure 1 A view of the invention having a foam layer on the lower surface of the backing layer, including a third reinforcement impregnated at least partially through its thickness.

[0034] [ Figure 4 ] is similar to Figure 1 A view of a backing layer having a foam layer on the lower surface thereof and a repositionable adhesive in contact with the floor.

[0035] [ Figure 5 ] is similar to Figure 3 , with a fourth reinforcement on the lower surface of the foam liner and optionally a repositionable adhesive in contact with the floor. DETAILED DESCRIPTION

[0036] refer to Figures 1 to 4 The present invention relates to a multilayer structure (1) for forming a floor covering, preferably for covering an aircraft floor, such as a honeycomb floor, but not limited to this application.

[0037] The multilayer structure (1) according to the invention has low manufacturing costs while having optimal properties in terms of adhesion to its support, dimensional stability, impact resistance and recyclability.

[0038] To this end, the multilayer structure (1) according to the invention comprises at least one surface layer (2) made of PVC, which is bonded to a backing layer (3b) also made of PVC.

[0039] According to the present invention, the surface quality of the multilayer structure (1) is 2000 to 3000 g / m 2 , preferably 2100 to 2600 g / m 2 , and between the surface layer (2) and the backing layer (3b) from top to bottom, it includes a first woven reinforcement (5a), an intermediate layer (3a), and a second woven reinforcement (5b), which are bonded to each other, the surface layer (2) and the backing layer (3b) by an adhesive layer (6) in the form of a hot melt film, and the hot melt film is, for example, a copolyamide, a thermoplastic polyurethane or a copolyester, or a cross-linked polyurethane adhesive layer.

[0040] The middle layer (3a) and the backing layer (3b) are each made of PVC and include:

[0041] - thickness of 100 μm to 200 μm;

[0042] - 5 to 25 parts per hundred parts of resin (phr), preferably 6 to 15 phr of plasticizer, wherein "phr" means parts per hundred parts of resin, the resin being the PVC of the intermediate layer (3a) and the backing layer (3b);

[0043] Preferably, a flexural strength (in particular B-bend of PVC films) between 0.30 mN.m and 1.5 mN.m, measured according to ISO 2493-2 on a "Taber Stiffness" test bench "Taber Industries", model "TABER 150-E".

[0044] The thickness of the adhesive layer (6) is usually 10 to 100 μm, preferably 10 to 50 μm.

[0045] Each intermediate layer and / or backing layer may be free of fillers, or may optionally include 1 to 50 phr of fillers. The fillers may be selected from the group consisting of calcium carbonate, chalk, kaolin, talc, silicon dioxide. Each intermediate layer and / or backing layer may also contain at least one additive selected from the following group: heat stabilizers, desiccants, lubricants, processing aids, pigments, flame retardants.

[0046] Limiting the amount of plasticizer prevents the plasticizer from migrating into the double-sided adhesive typically used to bond the multilayer structure (1) to the floor, thereby preventing the adhesive properties of the adhesive from deteriorating over time.

[0047] The flexural strength was tested in the machine direction and determined as the average bending moment of 10 measurements, i.e. 5 bending movements in one direction and 5 bending movements in the opposite direction.

[0048] The resulting multilayer structure (1) thus has a low weight, limiting its impact on the fuel consumption of the vehicle that carries it, while satisfying the mechanical constraints of this application, in particular in terms of resistance to telegraphing and resistance to warping.

[0049] The surface layer (2) may comprise a top layer (2a), in particular a wear-resistant layer, and a (see Figure 1 ) or more (see Figure 2 ) An interlayer (4) made of plasticized PVC, for example, with a plasticizer content greater than 15 phr, preferably less than 40 phr. Each interlayer may be filler-free or optionally include 1 to 150 phr of filler. The filler may be selected from the group consisting of calcium carbonate, chalk, kaolin, talc, silicon dioxide. Each interlayer may also contain at least one additive selected from the following group: heat stabilizer, desiccant, lubricant, processing aid, pigment, flame retardant.

[0050] The top layer (2a) and the interlayer (4) are bonded together, for example, by lamination (ie, thermal lamination). For example, the thickness of the top layer (2a) is preferably 0.35 mm to 0.55 mm, and the thickness of each interlayer (4) is preferably 0.15 mm to 0.60 mm.

[0051] The top layer (2a) is plasticized and optionally filled and may optionally have a surface varnish known to those skilled in the art to ensure easy maintenance. It may also contain at least one additive selected from the following group: UV heat stabilizers, desiccants, lubricants, processing aids, pigments, flame retardants.

[0052] According to a specific embodiment, the top layer (2a) is transparent to visible light of the human eye, and the interlayer (4) placed directly below the top layer (2a) can take the form of a film with a pattern printed on its side facing the top layer (2a). In this case, it is preferred to place an opaque second interlayer (4) under the printed film to ensure sufficient opacity of the pattern and avoid seeing the structure of the first woven reinforcement (5a). Alternatively, the pattern can be printed directly on the back of the top layer, facing the interlayer (4).

[0053] The first and second woven reinforcements (5a, 5b) improve the rigidity and dimensional stability of the multilayer structure (1) and may be in the form of glass fabrics.

[0054] Due to the lack of affinity of the woven reinforcements (5a, 5b) with PVC, these woven reinforcements (5a, 5b) are bonded to the surface layer (2), the intermediate layer (3a) and the backing layer (3b) via an adhesive layer (6), which is, for example, in the form of a hot melt film (e.g. copolyamide CoPA, thermoplastic polyurethane TPU or thermoplastic copolyester CoPES), a cross-linked polyurethane PUR layer, applied as a "hot melt" adhesive well known to those skilled in the art.

[0055] The first and / or second reinforcement (5a, 5b) is preferably woven in a plain weave, but is not limited thereto. Twill or satin weaves are also conceivable.

[0056] The first and / or second braided reinforcement (5a, 5b) is preferably made of glass fibers, polyamide fibers or polyester fibers.

[0057] The weight of the glass fiber can be 22Tex to 68Tex. The weight of the polyester fiber can be about 1100dtex. The weight of the polyamide fiber can be 44dtex to 78dtex. The thickness of the first and / or second braided reinforcement (5a, 5b) is usually 150μm to 300μm, preferably 165μm to 205μm. The surface quality of the first and / or second braided reinforcement (5a, 5b) is usually 150 to 300g / m 2 However, this value depends on the nature of the fibers used.

[0058] When the first and / or second woven reinforcement (5a, 5b) is made of glass fiber, the number of warp threads is 17 to 18 per centimeter, and the number of weft threads is 13.5 to 14 per centimeter.

[0059] If the number of warp threads is lower than 17 threads per centimeter or the number of weft threads is lower than 13.5 threads per centimeter, the first and / or second knitted reinforcement (5a, 5b) becomes porous, especially when the weight is between 22 and 68 Tex.

[0060] Preferably, the first and / or second woven reinforcement (5a, 5b) is impregnated with a thermoplastic or thermosetting polymer in an amount of 1% to 10% by weight of the impregnated woven reinforcement to maintain recyclability, provide greater rigidity, and limit or eliminate glue penetration that could clog the lamination lines during layer assembly.

[0061] The thermosetting or thermoplastic polymer used for impregnating the first and / or second braid reinforcement may be selected from the group consisting of polyurethane resins, polyester resins, phenolic resins, epoxy resins, polysulfones, vinyl ester resins, epoxy-acrylic resins and mixtures thereof.

[0062] Preferably, reference Figure 3 and Figure 4 In order to improve the resistance to the "print-through" and "warping" phenomena (also called "waving") known to those skilled in the art, the foam layer (7) is bonded to the lower surface of the backing layer (3) by means of an adhesive layer (6) in the form of a "hot melt" adhesive (e.g. polyurethane PUR or copolyester "CoPES").

[0063] The density of the foam layer (7) is advantageously 0.15 to 0.25, preferably 0.20 to 0.25, and the thickness is advantageously 1.5 to 3 mm, preferably 1.9 to 2.5 mm, to improve anti-printing and anti-warping (or waving) properties.

[0064] Preferably, reference Figure 3 The foam layer (7) comprises a third reinforcement (9) at least partially impregnated in its thickness to improve the resistance of the foam layer and the overall multilayer structure. The third reinforcement (9) can be a non-woven fabric layer, preferably a glass fiber, cellulose or polyester mesh, used alone or in combination; a reinforcing grid, preferably a glass fiber or polyester grid; or a composite material comprising a non-woven fabric layer bonded to a reinforcing grid. The weight of the non-woven fabric layer of the third reinforcement (9) is generally 20 to 80 g / m 2 The weaving density of the grid of the third reinforcement (9) is generally greater than 2 x 2 and the number of warps and wefts is between 34 and 68 tex. The third reinforcement may optionally include an adhesive, such as PVAc (polyvinyl acetate). The foam layer may be obtained from a PVC plastisol coated on the third reinforcement (9) and then gelled to at least partially impregnate the reinforcement over its thickness. Preferably, the third reinforcement (9) is positioned relative to the backing layer (3b) and bonded to the backing layer (3b) by an adhesive layer (6).

[0065] Preferably, reference Figure 4The multilayer structure (1) comprises a repositionable double-sided adhesive layer (8) located on the lower surface intended to come into contact with the floor, that is, for example, directly on the lower surface of the backing layer (3), or the lower surface of the non-woven fabric layer, which adheres better to the multilayer structure (1) than to the floor, so as to facilitate installation.

[0066] Preferably, reference Figure 5 The fourth reinforcement (10) is bonded to the lower surface of the foam layer (7) and at least partially impregnated through its thickness to improve the anti-printing properties of the entire multilayer structure. The fourth reinforcement (10) can be a non-woven fabric layer, preferably a glass fiber, cellulose or polyester mesh alone or in combination, or a composite material comprising a non-woven fabric layer bonded to a reinforcement grid (preferably a glass fiber or polyester grid). The non-woven fabric layer of the fourth reinforcement (10) when used alone typically weighs 80 g / m 2 Up to 150g / m 2 , the weight in composite materials is usually 20g / m 2 Up to 150g / m 2 When a composite material is used for the fourth reinforcement (10), the grid of the composite material generally has a weaving density greater than 2 x 2 and a warp and weft count of 34 to 68 tex. The fourth reinforcement may optionally include an adhesive, such as PVAc (polyvinyl acetate). The foam layer (7) may be obtained from a PVC plastisol applied to the third reinforcement (9), and then the fourth reinforcement (10) is placed on the third reinforcement. The plastisol is then gelled to at least partially impregnate the third reinforcement (9) and the fourth reinforcement (10) over its thickness.

[0067] The applicant has tested product A in accordance with the present invention; the surface quality of product A is 2150 g / m 2 ,include:

[0068] - Top layer (2a) made of pure PVC, 0.50 mm thick, with a surface mass of 640 g / m 2 ;

[0069] - Interlayer (4) made of PVC, 0.50 mm thick, surface mass 640 g / m 2 ;

[0070] - Adhesive layer (6) in the form of a hot melt film, 0.045 mm thick, with a surface mass of 50 g / m 2 ;

[0071] - Impregnated first braided reinforcement (5a) with a thickness of 0.15 mm and a surface mass of 223 g / m 2 ;

[0072] - an adhesive layer (6) in the form of a cross-linked polyurethane adhesive with a surface mass of 35 g / m 2 ;

[0073] - an intermediate layer (3a) made of plasticized PVC with 8 phr of plasticizer and a thickness of 140 μm and a flexural strength of 0.35 mN.m measured according to ISO 2493-2;

[0074] - an adhesive layer (6) in the form of a cross-linked polyurethane adhesive with a surface mass of 35 g / m 2 ;

[0075] - Impregnated second braided reinforcement (5b) with a thickness of 0.15 mm and a surface mass of 223 g / m 2 ;

[0076] - an adhesive layer (6) in the form of a cross-linked polyurethane adhesive with a surface mass of 35 g / m 2 ;

[0077] - a backing layer (3b) made of plasticized PVC with 8 phr of plasticizer and a thickness of 140 μm,

[0078] The flexural strength measured according to ISO 2493-2 is 0.35 mN.m.

[0079] Table 1

[0080]

[0081] In Table 1, we observe that product A meets all requirements in terms of surface quality, thickness, compression force, bending moment, flammability, and peel resistance. In addition, recyclability is improved compared to existing solutions. Dimensional stability, hot bending, and adhesion to the carrier (peel resistance) are also satisfactory.

[0082] A second series of tests was conducted on product B. Product B conforms to the invention and includes the features and different layers of product A, according to Figure 4 , a foam layer (7) is added which is bonded to the backing layer (3b) by an adhesive layer (6), the adhesive layer (6) being in the form of a cross-linked polyurethane adhesive having a surface mass of 35 g / m 2 .

[0083] The foam layer (7) comprises a third reinforcement (9) partially impregnated in its thickness, has a thickness of 150 μm and is in the form of a composite material comprising a nonwoven layer made of cellulose and polyester fibers, with a weight of 20 g / m 2 The nonwoven fabric layer is bonded to the glass fiber reinforced grid by PVAc adhesive and has a weave density of 5×3 and a warp and weft number of 34tex×34tex.

[0084] The foam layer is obtained from a PVC plastisol coated on the third reinforcement (9) and then gelled to at least partially impregnate said reinforcement throughout its thickness.

[0085] Different types of foam layers (7) were tested, varying their density, surface quality and thickness. The anti-print through test consisted of visually observing the appearance of substrate defects on the surface of the multilayer structure (1).

[0086] The results are graded as follows: no obvious defects (+++), obvious but acceptable defects (++), obvious and unacceptable defects (+). The warpage resistance test involves visually observing the appearance of bulges on the surface of the multilayer structure (1). The results are graded as follows: no obvious bulges (+++), obvious but acceptable bulges (++), obvious and unacceptable bulges (+).

[0087] Table 2

[0088]

[0089] In Table 2, we observe that a foam layer (7) with a density of 0.20 to 0.35 and a thickness of 1.9 to 2.5 provides the best compromise between the indentation resistance of the multilayer structure (1) and its resistance to telegraphing and warping. This solution is therefore preferred.

[0090] A third series of tests was conducted on two variants of product C. Product C is in accordance with the invention and comprises the characteristics of product B and a different layer, with the addition of a fourth reinforcement (10) bonded to the lower surface of the foam layer (7) and partially impregnating its thickness, and a repositionable double-sided adhesive layer (8) bonded to the lower surface of the fourth reinforcement (10). Different reinforcements were tested compared to product B, which also had a repositionable double-sided adhesive layer (8) bonded to the lower surface of the foam layer (7).

[0091] In this third series of tests, the foam layer (7) in both products consisted of a foam having a density of 0.23 and a surface mass of 450 g / m 2 , PVC plastisol with a thickness of 2 mm.

[0092] The fourth reinforcement (10) is a composite material or a non-woven fabric.

[0093] In a first variant of product C, the composite material comprises a nonwoven layer made of cellulose and polyester fibers with a weight of 20 g / m 2 , bonded to the glass fiber reinforced grid via PVAc (polyvinyl acetate) adhesive, with a weave density of 5 x 3 and a warp and weft count of 34tex x 34tex.

[0094] In the second variant of product C, the nonwoven is made of polyester and has a surface mass of 80 g / m 2 .

[0095] The same double-sided adhesive layer (8) was tested for repositionability according to Boeing BMS 8-434 8.11. The goal was to obtain a peel resistance value greater than 1.5 lbs / 2 in.

[0096] [Table 3]

[0097]

[0098] The repositionability test showed that the addition of the fourth reinforcement (10) did not reduce the repositionability of product C. An anti-print-through test was carried out by comparing the multilayer structure of the invention with two commercial products, "Batiflex AV135" and "Batiflex AVM 282", which do not include a third reinforcement combined with the foam layer (7). The test consists in placing metal balls with diameters of 1, 1.5 and 2 mm, as well as strips 0.2 mm thick, between a flat substrate and a sticky floor covering on the substrate. The covering is then exposed to oblique light and a rating from 1 to 5 is given to characterize the visibility of the balls or strips on the surface of the covering. The higher the rating, the more obvious the balls or strips, with the aim of hiding these defects as much as possible.

[0099] [Table 4]

[0100]

[0101] Tests have shown that the anti-print-through properties of the invention are improved compared to "Batiflex AV135" and "Batiflex AVM282" floor coverings for aircraft floor panels. 1 mm balls are completely masked and surface defects of other objects are significantly reduced. A trolley test was conducted according to Boeing BMS 8-434 8.2 between product B and a second variant of product C, product C comprising a fourth reinforcement (10) nonwoven 80 g / m 2 The aim was to observe no delamination of the multilayer structure (1), in particular of the foam layer (7), after 20,000 trolley cycles. The test showed that product B showed initial delamination after 20,000 cycles, while product C showed no delamination. The presence of the fourth reinforcement (10) improves the peeling resistance of the structure according to the invention comprising the foam layer (7).

Claims

1. A multilayer structure (1) for forming a floor covering, comprising at least one surface layer (2) bonded to a backing layer (3b), both the surface layer (2) and the backing layer (3b) being made of PVC; characterised in that The multilayer structure (1) comprises, from top to bottom, between the surface layer (2) and the backing layer (3b): a first woven reinforcement (5a), an intermediate layer (3a), and a second woven reinforcement (5b), which are all bonded to each other, to the surface layer (2), and to the backing layer (3b) by an adhesive layer (6) in the form of a hot melt film, such as a copolyamide or copolyester or cross-linked polyurethane adhesive layer; and the surface mass of the multilayer structure (1) is 2000 to 3000 g / m 2 , the middle layer (3a) and the backing layer (3b) are made of PVC and each comprises: - thickness of 100 μm to 200 μm; - 5 to 25 phr of plasticizer, preferably 6 to 15 phr of plasticizer.

2. The multilayer structure (1) according to claim 1, characterized in that The intermediate layer (3a) and / or the backing layer (3b) comprises a flexural strength measured according to ISO 2493-2 of between 0.30 mN.m and 1.5 mN.m.

3. The multilayer structure (1) according to any one of the preceding claims, characterized in that The surface layer (2) comprises a top layer (2a) and one or more interlayers (4) made of plasticized PVC.

4. The multilayer structure (1) according to claim 3, characterized in that The top layer (2a) is transparent and the interlayer (4) placed directly below the top layer (2a) is a film printed with a pattern.

5. The multilayer structure (1) according to one of the preceding claims, characterized in that The first braided reinforcement (5a) and / or the second braided reinforcement (5b) are impregnated with a thermoplastic or thermosetting polymer in an amount of 1% to 10% by weight of the impregnated braided reinforcement.

6. The multilayer structure (1) according to one of the preceding claims, characterized in that The foam layer (7), preferably made of PVC, is bonded to the lower surface of the backing layer (3b) via an adhesive layer (6) in the form of a hot-melt film or a cross-linked polyurethane adhesive layer.

7. The multilayer structure (1) according to claim 6, characterized in that The foam layer (7) has a density of 0.15 to 0.25, preferably 0.20 to 0.25, and a thickness of 1.5 to 3 mm, preferably 1.9 to 2.5 mm.

8. The multilayer structure (1) according to claim 6, characterized in that The foam layer (7) comprises a third reinforcement (9) impregnated at least partially throughout its thickness.

9. The multilayer structure (1) according to claim 6, characterized in that The foam layer (7) comprises a fourth reinforcement (10) impregnated at least partially throughout its thickness.

10. The multilayer structure (1) according to one of the preceding claims, characterized in that The multilayer structure comprises a repositionable double-sided adhesive layer (8) on the lower surface intended to come into contact with the floor.

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