LU101661B1

LU101661B1 - Sheet flooring in roll for loose-lay installation

Info

Publication number: LU101661B1
Application number: LU101661A
Authority: LU
Inventors: Croce Pascal Di; Nicolas Boquillon
Original assignee: Tarkett Gdl Sa
Priority date: 2020-03-05
Filing date: 2020-03-05
Publication date: 2021-09-14
Also published as: EP4115032A1; WO2021175981A1

Abstract

A sheet flooring (10) for loose-lay installation on a subfloor is provided in the form of a roll and comprises a core layer assembly (12) including one or more core layers.. At least one of the one or more core layers comprises a reinforcement layer (14, 14a, 14b). The sheet flooring has a Young's modulus in the range from 115 to 255 MPa along the longitudinal axis and a yield stress along the longitudinal axis in the range from 2.5 to 8 MPa.

Description

DESCRIPTION © SHEET FLOORING IN ROLL FOR LOOSE-LAY INSTALLATION Field of the Invention

[0001] The invention generally relates to decorative sheet flooring for loose-lay installation. According to a preferred embodiment of the invention, a heterogeneous, PVC-based floor covering, in roll form in accordance with ISO standards 10582:2017 or 26986:2010 is provided.

Background of the Invention

[0002] Heterogeneous sheet flooring comprises of a wear layer and other layers which differ in composition and/or design and can contain a reinforcement (see e.g.

ISO standard 10582:2017). In contrast, a homogeneous floor covering is defined as a floor covering with one or more layers of the same composition and colour, patterned throughout its thickness (see e.g. ISO standard 10581:2019).

[0003] Flooring is typically commercialized in various forms, in particular individual floor covering elements such as tiles, planks, panels or the like, or as so-called sheet flooring (also: endless or continuous flooring). The market increasingly demands for loose-lay flooring solutions, i.e. flooring that need not be glued to the subfloor. Loose- lay tiles, planks, panels, etc. are already well established on the market. More recently, the flooring industry has sensed an increasing demand for loose-lay sheet flooring, not only for domestic (residential) use but also for use in commercial and industrial areas.

Summary of the Invention

[0004] Conception of loose-lay sheet flooring is challenging, especially when the flooring is intended for commercial and light industrial use levels. The reason for this is that the most important advantage of loose-lay flooring lies in easier and thus less time-consuming installation in comparison with glued-down flooring. Ease-of- installation, however, was found not to be easily reconcilable with technical requirements relating to the use of the flooring, such as high or heavy traffic resistance and robustness. In this context, “high traffic” relates to the high number of passes while “heavy traffic” relates to heavy loads.

[0005] An aspect of the invention thus pertains to sheet flooring addressing that problem. According to this inventive aspect, sheet flooring for loose-lay installation on a subfloor is provided in the form of a roll and comprises: a core layer assembly comprising one or more core layers, and a décor layer on top of the core layer assembly. At least one of the one or more core layers comprises a reinforcement layer. Without being limited thereto, the reinforcement layer could include or consist of a fibre veil or a reinforcement grid, or both.

[0006] The sheet flooring has a surface normal, as well as a longitudinal axis and a transverse axis, the longitudinal and transverse axes both being perpendicular to the surface normal, the longitudinal and transverse axes being perpendicular to each other. The sheet flooring has a Young's modulus in the range from 115 to 255 MPa, preferably in the range from 200 to 240 MPa, along the longitudinal axis and a yield stress (also: yield strength or stress at yield, corresponding to the stress at the first local maximum of the stress-strain curve obtained in a tensile test) along the longitudinal axis in the range from 2.5 to 8 MPa, preferably in the range from 4.5 to 7 MPa. As used herein, the transverse axis is parallel to the axis of the roll and the longitudinal axis corresponds to the machine direction during fabrication of the sheet flooring.

[0007] By evaluating feedback reports from professional flooring installation personnel and carefully analysing the mechanical properties of the tested flooring prototypes, the inventors have found that, to some extent surprisingly, ease-of- installation under the constraint of meeting the requirements relation to daily use of the flooring can be best guaranteed by tailoring the composition of the sheet flooring in such a way that the Young modulus and yield stress thereof are situated in the respective indicated ranges.

[0008] Preferably, the sheet flooring has a Young's modulus in the range from 115 to 255 MPa, more preferably in the range from 200 to 240 MPa, also along the transverse axis. Still more preferably, the sheet flooring has a Young's modulus in that range along any axis that is perpendicular to the surface normal. Preferably also, the sheet flooring has a yield stress along the transverse axis in the range from 2.5 to 8 MPa, more preferably in the range from 4.5 to 7 MPa.

[0009] The sheet flooring preferably further comprises a backing (more preferably: a 99 non-skid backing) attached to the back of the core layer assembly for contacting the subfloor.

[0010] The Young's modulus may be calculated as the ratio of stress to strain in the linear elasticity regime under uniaxial deformation, stress and strain being measured in a tensile test with a universal testing machine in accordance with European Standard EN ISO 527:2012, Parts 1-3. The yield stress corresponds to the stress at the first local maximum of the stress-strain curve obtained in such tensile test when deformation goes beyond the linear elasticity regime. In such tensile tests specimens of the flooring to be tested, dimensioned as per the requirements of the standard, are subjected to uniaxial deformation using the universal testing machine, while the applied tension and the resulting proportional deformation are recorded. The tests are carried out at normal conditions of temperature and pressure (21°C, 1023 hPa) and at a relative air humidity of 50%.

[0011] As used herein, the “core layer assembly” designates those layers of the sheet flooring the principal function of which is providing structural support to any other layer(s), such as, e.g., a décor layer, a wear layer, a backing and/or any intermediary layer(s).

[0012] As used herein, a “décor layer” is a layer with a visible motif (decorative pattern) that remains visible when the sheet flooring is in use as intended and that contributes to the outer appearance of the flooring. A décor layer is typically present on the sheet flooring when the sheet flooring belongs to the category of heterogeneous floorings. The décor layer could be a decorative wear layer. Alternatively, the sheet flooring could comprise a transparent or at least translucent wear layer on top of the décor layer. In that case, the décor layer could comprise a printing substrate and one or more layers of ink thereon, or, alternatively, the décor layer could consist of one or more ink layers, which are printed on the top surface of the core layer assembly or the back surface of the wear layer. When the décor layer consists of one or more ink layers printed on the back surface of the wear layer or on the top surface of the core layer assembly, the printing may be carried out directly on that surface or, if necessary, one or more intermediary primer layer facilitating adhesion of the ink(s) may be applied on that surface before the décor is printed. Any printing technique could be used for

| DP.TASO.0189/LU 4 . ; Co 11 © ; LU101661 generating the décor layer. Nevertheless, digital printing is particularly preferred in that context.

[0013] It should be noted that the sheet flooring according to the present invention could be a heterogeneous flooring as mentioned above or, alternatively, a homogeneous flooring, i.e. flooring with one or more layers of the same composition and colour, patterned throughout the thickness of the flooring. If the sheet flooring according to the present invention belongs to the category of homogeneous floor coverings, the décor stems from the patterning of the core layer assembly.

[0014] The sheet flooring preferably has a thickness in the range from 1.8 mm to

4.6 mm, more preferably in the range from 1.9 mm to 3.5 mm.

[0015] According to a preferred embodiment of the invention, the one or more core layers are layers of thermoplastic material, optionally containing mineral and/or organic filler material (e.g. calcium carbonate, clay, etc.)

[0016] The wear layer could comprise one or more layers of transparent or at least translucent thermoplastic material. Alternatively or additionally, the wear layer could contain mineral and/or organic filler material (e.g. corundum particles, polymeric reinforcement fibers, etc.)

[0017] The wear layer could also comprise a polyurethane topcoat, preferably a radiation-cured one (e-beam-cured or UV-cured PU). In case of a homogeneous sheet flooring, the core layer assembly could have such a topcoat.

[0018] The thermoplastic material of the wear layer and/or of the core layer(s) is, preferably, a PVC material.

[0019] When the reinforcement layer includes a fibre veil, the fibre veil preferably including polymeric and/or glass fibres. When the reinforcement layer includes a reinforcement grid, the reinforcement grid preferably includes or consists of polymeric and/or glass fibres.

[0020] The sheet flooring could be safety flooring, e.g., sheet flooring featuring particle-based enhanced slip resistance in accordance with European standard EN 13845:2017.

[0021] In the present document, the verb “comprise” and the expression “comprised of” are used as open transitional phrases meaning “consist at least of’ or “include”. The term “layer” designates one among plural sheets or thicknesses of material that make up the sheet flooring. Plural similar sheets or thicknesses assembled on top of one another could be considered a complex layer, provided that the assembly forms a functional unit. For instance, the wear layer could consist of a single sheet or a stack of sublayers. When the present document uses the words “top”, “bottom”, “above”, below” alone or in combination with another word in relation with the flooring or an element thereof, reference is made to the orientation of the flooring when used as finishing work, the decorative side facing upward. However, this is only to be taken as a naming convention in the context of the present document and must not be understood as implying that the invention be limited to the floor covering with that particular orientation. For example, the top surface of a layer may be oriented differently during the fabrication of the flooring. Inevitably also, when the sheet flooring is rolled up, the top face will not be facing upwards everywhere.

[0022] It should also be noted that different embodiments of the invention can be combined, unless it follows directly from context that embodiments are not compatible. The skilled person will appreciate that the combination of preferred optional features presented herein as preferred embodiments would typically result in a particularly preferred embodiment uniting the preferred optional features. Brief Description of the Drawings

[0023] The accompanying drawings illustrate several aspects of the present invention and, together with the detailed description, serve to explain the principles thereof. In the drawings: Fig. 1: is a schematic cross-sectional view of a sheet of flooring for loose-lay installation on a subfloor according to a first variant; Fig. 2: is a schematic cross-sectional view of a sheet of flooring for loose-lay installation on a subfloor according to a second variant; Fig. 3: is a schematic cross-sectional view of a sheet of flooring for loose-lay installation on a subfloor according to a third variant; Fig. 4: is a schematic perspective view of the installation of the floorings of Figs. 1, 2 or 3 from a roll.

Detailed Description a Preferred Embodiment

[0024] As schematically illustrated on Fig. 1, a piece of sheet flooring 10 for loose-lay installation on a subfloor comprises: a core layer assembly 12, including a reinforcement layer 14; a décor layer attached 16 on top of the core layer assembly 12, the décor layer 16 including a printing substrate 18 and a layer of ink forming a printed decorative motif 20 thereon; a nonskid backing 22 attached to the back of the core layer assembly 12 for contacting the subfloor, a wear layer 24 attached on top of the décor layer, including a radiation-cured topcoat

26.

[0025] Flooring 10 has a surface normal 28, a longitudinal axis 30 and a transverse axis 32, the longitudinal and transverse axes 30, 32 both being perpendicular to the surface normal 28. Furthermore, the longitudinal and transverse axes 30, 32 are perpendicular to each other. Both along the longitudinal axis 30 and the transversal axis 32, the flooring 10 has a Young's modulus in the range from 115 to 255 MPa, preferably in the range from 200 to 240 MPa, and a yield stress in the range from 2.5 to 8 MPa, preferably in the range from 4.5 to 7 MPa.

[0026] The Young's modulus is calculated as the ratio of stress to strain in the linear elasticity regime under uniaxial deformation. Stress and strain are measured with a universal testing machine in accordance with European Standard EN ISO 527:2012, Parts 1-3. Specifically, specimens of the flooring to be tested, dimensioned as per the requirements of the standard, are subjected to uniaxial deformation using the universal testing machine, while the applied tension and the resulting proportional deformation are recorded. The yield stress corresponds to the first local maximum of the stress when the deformation leaves the elastic regime. The tests are carried out at normal conditions of temperature and pressure (21°C, 1023 hPa) and at a relative air humidity of 50%.

[0027] Figs. 2 and 3 show variants of the sheet flooring 10 of Fig. 1. The construction of the sheet floorings of Figs. 2 and 3 is the same as that of the sheet flooring of Fig. 1

. . LU101661 except for the core layer assembly 12 comprising plural reinforcement layers 14, 14a (see Figs. 2 and 3) and 14b (see Fig. 3).

[0028] Fig. 4 illustrates installation of sheet flooring 10 from a roll 34 in accordance with a preferred aspect of the invention. Feedback reports from flooring specialists have been analysed and evaluated against the mechanical properties of the respective floorings. This has led the inventors to propose sheet flooring in rolls having the mechanical properties set forth herein. After careful analysis of the mechanical properties of the tested flooring prototypes, the inventors have surprisingly found that, ease-of-installation under the constraint of meeting the requirements relation to daily use of the flooring can be best guaranteed by tailoring the composition of the sheet flooring in such a way that the Young modulus thereof is situated in the range from 115 to 255 MPa and the yield stress in the range from 2.5 to 8 MPa.

Examples

[0029] The table below summarizes the construction and the properties of sheet floorings according to preferred embodiments of the invention. In the table, o YM means the Young modulus (measured in the longitudinal direction); o YS means the yield stress (measured in the longitudinal direction); o IA means the installation aptitude; o and TR means the traffic resistance.

|A was assessed by flooring installation experts who rated compliance with six criteria (general aspect of the product, packaging, ease of pose, coving aptitude, ease of cutting, and ease of welding) on a scale from 0 (no compliance) to 5 (full compliance). TR was measured as the number of turns a forklift could make on the loose-laid sheet flooring with one of its wheels blocked until damage became visible. {a [ROB [R Example 1: as in Fig. 1, with 14 — reinforcement | 20312 | 4.8+0.1 | 20 11 layer: glass veil, Total thickness: 2.66 mm (commercial reference: Johns 26 - top-coat : 0.01 mm Manville SH80/1) 24 - wear layer : 0.7 mm 16 (18+20) - décor layer : 0.4 mm 20 - layer ink : 0.01 mm 18 - printing substrate : 0.39 mm

12 - core layer assembly: 1.50 mm 40101661 22 - non-skid backing : 0.05 mm Example 2: as in Fig. 1, with: 14 — reinforcement | 218+3 | 5.7x0.8 | 19 13 layer: glass veil Total thickness: 3.21 mm (commercial reference: Porcher 26 - top-coat : 0.01 mm M4145) 24 - wear layer : 0.70 mm 16 (18+20) - décor layer : 0.9 mm 20 - layer ink : 0.01 mm 18 - printing substrate : 0.89 mm 12 - core layer : 1.6 mm Example 3: as in Fig. 2, with: 14 and 14a — 232+5 | 6.1+0.8 | 19 12 reinforcement Total thickness: 2.01 mm layers : glass veils (Commercial 26 - top-coat : 0.01 mm reference: Johns 24 - wear layer : 0.70 mm Manville SH 38/1) 16 (18+20) - décor layer : 0.60 mm 20 - layer ink : 0.01 mm 18 - printing substrate : 0.59 mm 12 - core layer : 0.70 mm

[0030] Installation aptitude and traffic resistance of loose-laid sheet flooring according to the invention were found to be above the respective averages of a set of comparable commercially available products.

[0031] While specific embodiments have been described herein in detail, those skilled in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Claims

| DP.TASO.0189/LU 9 | LU101661 Claims

1. A roll of sheet flooring for loose-lay installation on a subfloor, the sheet flooring comprising a core layer assembly comprising one or more core layers; at least one of the one or more core layers comprising a reinforcement layer; wherein the sheet flooring has a surface normal, a longitudinal axis and a transverse axis, the longitudinal and transverse axes both being perpendicular to the surface normal, the longitudinal and transverse axes being perpendicular to each other, and wherein the sheet flooring has a Young's modulus along the longitudinal axis in the range from 115 to 255 MPa, preferably in the range from 200 to 240 MPa, and a yield stress along the longitudinal axis in the range from

2.5 to 8 MPa, preferably in the range from 4.5 to 7 MPa.

2. The roll of sheet flooring as claimed in claim 1, wherein the sheet flooring has a Young's modulus in the range from 115 to 255 MPa, preferably in the range from 200 to 240 MPa, along the transverse axis.

3. The roll of sheet flooring as claimed in claim 1 or 2, wherein the Young's modulus is calculated as the ratio of stress to strain, stress and strain being measured with a universal testing machine in accordance with European Standard EN ISO

527.2012, Parts 1-3.

4. The roll of sheet flooring as claimed in any one of claims 1 to 3, wherein the sheet flooring has a yield stress along the transverse axis in the range from 2.5 to 8 MPa, preferably in the range from 4.5 to 7 MPa.

5. The roll of sheet flooring as claimed in any one of claims 1 to 4, further comprising a nonskid backing attached to the back of the core layer assembly for contacting the subfloor.

6. The roll of sheet flooring as claimed in any one of claims 1 to 5, comprising a décor layer on top of the core layer assembly.

7. The roll of sheet flooring as claimed in claim 6, wherein the décor layer is a decorative wear layer.

8. The roll of sheet flooring as claimed in claim 6 or 7, comprising a transparent or at least translucent wear layer on top of the décor layer.

. . . . . .. LU101661

9. The roll of sheet flooring as claimed in claim 8, wherein the wear layer comprises one or more layers of transparent or at least translucent thermoplastic material.

10. The roll of sheet flooring as claimed in any one of claims 7 to 9, wherein the wear layer contains mineral and/or organic filler material.

11. The roll of sheet flooring as claimed in any one of claims 7 to 10, wherein the wear layer comprises a radiation-cured polyurethane topcoat.

12. The roll of sheet flooring as claimed in any one of claims 1 to 11, wherein the sheet flooring has a thickness in the range from 1.8 mm to 4.6 mm.

13. The roll of sheet flooring as claimed in any one of claims 1 to 12, wherein the one or more core layers are layers of thermoplastic material, optionally containing mineral and/or organic filler material.

14. The roll of sheet flooring as claimed in any one of claims 1 to 13, wherein the reinforcement layer includes a fibre veil, the fibre veil including polymeric and/or glass fibres.

15. The roll of sheet flooring as claimed in any one of claims 1 to 14, wherein the reinforcement layer includes a reinforcement grid, the reinforcement grid comprising polymeric and/or glass fibres.

16. The roll of sheet flooring as claimed in any one of claims 1 to 15, wherein the sheet flooring features particle-based enhanced slip resistance in accordance with European standard EN 13845:2017.

17. The roll of sheet flooring as claimed in any one of claims 1 to 5 or 12 to 16, wherein the sheet flooring is a homogeneous flooring.

18. The roll of sheet flooring as claimed in claim 6, wherein the décor layer includes one or more digitally printed ink layers.