Multilayer comprising a main polyolefin-based layer

Abstract

The present invention relates to a multilayer comprising at least: a) a main layer having a composition, throughout its thickness, comprising at least 70% by mass of polyolefin, b) a surface layer, c) a protective layer. The invention also relates to the use of this multilayer in the automotive or leather goods sectors.

Description

Title of the invention: Multilayer comprising a main layer based on polyolefin. Field of the invention

[0001] The present invention relates to a multilayer material in which the main layer comprises at least one polyolefin and polyurethane. The invention also relates to the use of this multilayer material in the following fields: automotive, leather goods... Previous art

[0002] In the automotive field, the functions of the dashboard and door panel generally rely on a main structure (insert) made of thermoplastic, often polyolefin, although other materials such as ABS can be used. To meet current or future environmental requirements, manufacturers must develop structures incorporating recycled plastic materials (RPM). One of the main constraints related to RPM is aesthetic, as RPM is generally dark in color and its shade range is not always predictable. Thus, these new structures, due to their material design (presence of RPM), may not meet designers' expectations. Therefore, there is a need to develop a technical sheet (multilayered polymer material) to cover these structures and, consequently, provide a satisfactory finish, for example, light-colored, solid-color options.

[0003] Another issue concerns the association between the technical sheet (multilayer) and the main structure based on MPR. Indeed, the technical sheet must be compatible with conventional techniques such as overmolding (single-step process), display (hot melt bonding), and thermoforming (thermoforming display process).

[0004] Therefore, conventional multilayers cannot be used.

[0005] Polyolefin multilayers are commonly used in many areas, particularly in the manufacture of dashboards, door panels and floor mats in the automotive industry.

[0006] The manufacture of multilayers necessarily generates waste (scrap) whose recycling is generally problematic, particularly due to the presence of polymers of different types, or even incompatible with each other. Indeed, the different layers of multilayers may be made up of polymers that are incompatible in the molten state, that is to say, during the preparation of the layers, the bond between the layers being ensured by an adhesive.

[0007] In addition, the properties of a layer comprising recycled materials are generally not satisfactory, as points of weakness may appear.

[0008] Consequently, there is a need to develop solutions enabling the recycling of these large quantities of materials without requiring prior sorting and therefore additional energy and logistical constraints.

[0009] The present invention makes it possible to solve these problems (compatibility with an MPR-based structure, recycling of MPR in a multilayer) by integrating within a multilayer a specific layer based on polyolefin and advantageously on cross-linked polyurethane (varnish). Description of the invention

[0010] The present invention relates to a multilayer combining different layers of polyolefin and / or polyurethane.

[0011] More specifically, the present invention relates to a multilayer comprising at least: a) a main layer having a lower face FICp and an upper face FSCp, the main layer having a thickness of between 0.2 and 2.2 mm and a basis weight of between 150 and 2100 g / m2, the main layer having a composition, throughout its thickness, comprising: * at least 70% by mass of polyolefin, and * advantageously cross-linked polyurethane, b) a surface layer having a thickness less than or equal to 0.12 mm and a basis weight less than 110 g / m2, the surface layer being a thermoplastic polymer film, preferably selected from: polyolefin; polyurethane and mixtures thereof, the surface layer having a lower face FICs opposite the upper face FSCp of the main layer, and an upper face FSCs, c) a protective layer facing the top face of the surface layer, the protective layer being based on cross-linked polyurethane and having a polyurethane weight between 1 and 25 g / m2.

[0012] The expression "opposite" means that two elements are facing each other. This also covers the case where two layers are separated by an intermediate layer, for example by a layer of glue or by dots of glue.

[0013] Underlayer

[0014] According to a particular embodiment, the multilayer also includes a sublayer, opposite the lower face FICp of the main layer.

[0015] This underlayer is advantageously made of textile material or polyolefin foam.

[0016] Thus, the multilayer may include an underlayer made of textile material (for example, jersey, three-dimensional textile, non-woven fabric, etc.) which is bonded to the underside FICP of the main layer. In this case, the underlayer advantageously has a thickness of between 0.1 and 6 mm and a basis weight advantageously between 30 and 300 g / m².

[0017] The multilayer may include a polyolefin foam underlayer, which is advantageously extruded or bonded to the lower face FICp of the main layer. In this case, the underlayer advantageously has a thickness of between 1 and 6 mm, preferably 1.5 to 3 mm, and a density advantageously of between 67 and 100 kg / m³, preferably between 67 and 71 kg / m³.

[0018] According to another particular embodiment, the multilayer comprises a polyolefin foam underlayer having a lower face FISCm covered with a crosslinked polyurethane-based layer and an upper face FSScm which is opposite the lower face FICp of the main layer. Main layer

[0019] The composition of the main layer comprises, throughout its entire thickness, by mass: * at least 70% polyolefin, advantageously 80 to 95%, * advantageously 30% or less of crosslinked polyurethane, advantageously from 0.5 to 15%, for example from 0.5 to 5%.

[0020] When the multilayer includes a textile underlayer, the main layer advantageously comprises at least 70% by mass of polyolefin.

[0021] When the multilayer comprises a polyolefin foam underlayer, the main layer advantageously comprises at least 80% by mass of polyolefin.

[0022] Advantageously, the main layer has a density between 0.89 and 0.97, more advantageously between 0.89 and 0.92. The density may be lower when the main layer has a cellular structure.

[0023] Advantageously, the main layer has a basis weight of between 150 and 1300 g / m2, more advantageously between 400 and 500 g / m2.

[0024] According to a particular embodiment, the main layer has a basis weight of between 400 and 800 g / m2 and a thickness of between 0.45 and 0.90 mm, for example a basis weight of 450 g / m2 and a thickness of 0.5 mm.

[0025] According to a particular embodiment, the polyolefin of the main layer is a mixture of linear polyolefin and crosslinked polyolefin.

[0026] Advantageously, the composition of the main layer comprises cross-linked polyurethane.

[0027] According to a particular embodiment, the composition of the main layer comprises: - a linear polyolefin and / or a cross-linked polyolefin, - polyurethane and / or cross-linked polyurethane, - at least one additive chosen from: stabilizers (in particular thermal stabilizers), antioxidants, flame retardants, anti-UV agents, lubricants, fillers (for example silica), expanding agents, hot melt adhesives (advantageously polyolefin or polyurethane based), mineral fillers, colorants, pigments and mixtures thereof.

[0028] In general, the composition of the main layer may include compounds of plant origin, for example starch.

[0029] Linear polyolefin is advantageously chosen from the group comprising polyethylenes, polypropylenes, polybutenes, polypentenes, poly(4-methylpentene), olefin copolymers (for example ethylene-propene (EP) copolymers, ethylene-propene-diene (EPDM) copolymers...), elastomeric polyolefins and their mixtures.

[0030] Crosslinked polyolefin is advantageously chosen from the group comprising polyethylenes, polypropylenes, polybutenes, olefin copolymers, styrenic resins, elastomers, and mixtures thereof.

[0031] According to a preferred embodiment, the main layer comprises 5 to 100% by mass of recycled materials, for example 10 to 50% by mass, or 20 to 40% by mass.

[0032] Recycled materials can come from any type of industry, including the automotive industry (dashboards, door panels, etc.). Indeed, the polymers of the main layer are commonly used because of their lightness and versatility.

[0033] Thus, the main layer is advantageously derived, in part or entirely, from the recycling of polyolefin foam and varnished polyolefin films, the varnish being cross-linked polyurethane.

[0034] In general, the presence of varnish in the main layer can be seen with the naked eye because it provides a discontinuous visual appearance.

[0035] The present invention thus makes it possible to recycle, within the same layer, materials whose properties generally require a compatibilizing agent. However, according to a particular embodiment, the main layer is devoid of a compatibilizing agent between the polyolefin and the cross-linked polyurethane. Surface layer

[0036] As already indicated, the multilayer comprises a surface layer having a lower face FICs opposite the upper face FSCp of the main layer, and an upper face FSCs-

[0037] The surface layer has a thickness less than or equal to 0.12 mm, advantageously between 0.070 mm and 0.12 mm.

[0038] The surface layer has a basis weight of less than 110 g / m2, advantageously between 70 and 85 g / m2, more advantageously between 75 and 80 g / m2.

[0039] The surface layer is advantageously a thermoplastic polymer film, preferably selected from: polyolefin; polyurethane; and mixtures thereof.

[0040] According to a particular embodiment, the surface layer may be a thermoplastic polymer multilayer, for example a polyolefin multilayer or a multilayer having at least one polyolefin layer and at least one polyurethane layer. The multilayer may also include at least one layer made of a mixture of polyolefin and polyurethane. Protective layer

[0041] As already indicated, the multilayer includes a protective layer facing the top face of the surface layer.

[0042] The protective layer is based on cross-linked polyurethane and has a polyurethane weight between 1 and 25 g / m2. Multilayer and its use

[0043] According to a particular embodiment, the multilayer comprises (is advantageously made up of) the following layers: - protective layer with a weight between 1 and 25 g / m2, - surface layer with a weight of less than 110 g / m2, - main layer with a weight of less than 2100 g / m2, - layer of glue, - textile underlayer.

[0044] According to another particular embodiment, the multilayer comprises (is advantageously made up of) the following layers: - protective layer with a weight between 1 and 25 g / m2, - surface layer having a weight of less than 110 g / m2, - main layer having a weight of less than 2100 g / m2.

[0045] According to another particular embodiment, the multilayer comprises (is advantageously made up of) the following layers: - protective layer with a weight between 1 and 25 g / m2, - surface layer with a weight less than 110 g / m2, - main layer with a weight of less than 2100 g / m2, - foam underlayer.

[0046] According to another particular embodiment, the multilayer comprises (is advantageously made up of) the following layers: - protective layer with a weight between 1 and 25 g / m², - surface layer with a weight less than 110 g / m², - main layer with a weight less than 2100 g / m², - a foam layer, - layer of glue, - textile underlayer.

[0047] The multilayer may include one or more intermediate layers, for example made of polyolefin.

[0048] The multilayer can be grained and / or printed.

[0049] The multilayer may also include a varnish (polyurethane) layer on the lower face FICp of the main layer when the multilayer does not include an underlayer or on the lower face of the underlayer when the multilayer includes an underlayer.

[0050] When deposited on the reverse side of the multilayer (main layer or underlayer), the varnish can have a binding function to facilitate the bonding of the multilayer.

[0051] When deposited on the surface of the multilayer, the varnish constitutes the protective layer which has a protective function and advantageously an aesthetic function.

[0052] The multilayer material according to the invention can be used in particular in one of the following fields: automotive, leather goods, ... Multilayer preparation process

[0053] The present invention also relates to a method for manufacturing the multilayer. This method includes the preparation of a laminate comprising a main layer, a surface layer and a protective layer, the main layer having a lower face FICp and a upper face FSCp, the surface layer having a lower face FICs opposite the upper face FSCp of the main layer, and an upper face FSCs, the protective layer being deposited on the upper face FSCs of the surface layer.

[0054] Optionally, the multilayer can be grained, advantageously in line in a calender.

[0055] During the extrusion assembly process, the graining cylinder can press the material to give it its final shape.

[0056] According to a particular embodiment, the main layer is extruded onto the surface layer, the surface layer being, prior to extrusion, a thermoplastic polymer film (advantageously made of polyolefin or polyurethane) associated with the protective layer.

[0057] According to another particular embodiment, the main layer is extruded between the surface layer and a sub-layer, the surface layer being, prior to extrusion, a thermoplastic polymer film associated with the protective layer, the sub-layer being made of polyolefin foam.

[0058] Thus, when the underlayer is made of polyolefin foam, it is advantageously combined with the main layer by calendering.

[0059] When the underlayer is made of textile material, it is advantageously joined to the main layer by gluing, for example by means of a layer of glue or dots of glue.

[0060] According to another particular embodiment, the main layer is associated with an underlayer by direct calendering (without glue) or indirect calendering (with glue), the underlayer being made of textile material or polyolefin foam.

[0061] According to another particular embodiment, the main layer is advantageously prepared by extruding thermoplastic granules having a composition comprising: * at least 70% by mass of polyolefin, and * advantageously cross-linked polyurethane, the granules (optionally ground) having an average size between 2 and 15 mm.

[0062] The composition of the thermoplastic granules can be derived, at least partially, from recycled materials.

[0063] As already indicated, the invention also relates to the use of this multilayer in the automotive or leather goods sector. Examples

[0064] The following multilayer was prepared in the following manner: - Application of a layer of varnish (5g / m2 of cross-linked polyurethane) on a foam underlayer (cross-linked polyolefin), - Application of a protective layer (2x5g / m2 of cross-linked polyurethane) on a polyolefin surface layer (80 g / m2, 85pm), - Extrusion of the main layer (220°C, 370 g / m2, 500 µm) between the surface layer (multilayer polyethylene / polypropylene + colorant and UV stabilizer) and the foam underlayer, - Consolidation of the multilayer by passing through a calender (rubber / steel).

[0065] The main layer comprises (by mass) 99% by mass of polyolefin (of which 4.5% is cross-linked polyolefin) and 1% of cross-linked polyurethane; 20% by mass of the main layer being of recycled origin.

Claims

Demands

1. Multilayer comprising at least: a) a main layer having a FICP bottom face and an FSCp top face, the main layer having a thickness of between 0.2 and 2.2 mm and a basis weight of between 150 and 2100 g / m2, the main layer having a composition, throughout its thickness, comprising at least 70% by mass of polyolefin, and b) a surface layer having a thickness less than or equal to 0.12 mm and a basis weight of less than 110 g / m2, the surface layer being a thermoplastic polymer multilayer film, preferably selected from: polyolefin;polyurethane and their mixtures, the surface layer having a lower face FICs opposite the upper face FSCp of the main layer, and an upper face FScs, c) a protective layer opposite the upper face FSCs of the surface layer, the protective layer being based on cross-linked polyurethane and having a polyurethane weight between 1 and 25 g / m2.;

2. Multilayer according to claim 1, characterized in that the composition of the main layer comprises cross-linked polyurethane.

3. Multilayer according to claim 1 or 2, characterized in that the multilayer comprises an underlayer of textile material or polyolefin foam, the underlayer being advantageously opposite the lower face FIC p of the main layer.

4. Multilayer according to any one of claims 1 to 3, characterized in that the multilayer comprises a polyolefin foam underlayer having a lower face FISCm covered with a crosslinked polyurethane-based layer and an upper face FSscm advantageously opposite the lower face FICP of the main layer.

5. Multilayer according to any one of claims 1 to 4, characterized in that the composition of the main layer comprises linear polyolefin and crosslinked polyolefin.

6. Multilayer according to any one of claims 1 to 5, characterized in that the composition of the main layer comprises: - a linear polyolefin and / or a cross-linked polyolefin, - polyurethane and / or cross-linked polyurethane, - at least one additive selected from: stabilizers, antioxidants, flame retardants, UV inhibitors, lubricants, fillers, blowing agents, hot melt adhesives, mineral fillers, colorants, pigments and mixtures thereof, the linear polyolefin being selected from the group comprising polyethylenes, polypropylenes, polybutenes, polypentenes, poly(4-methylpentene), olefin copolymers, elastomeric polyolefins and mixtures thereof, the cross-linked polyolefin being selected from the group comprising polyethylenes, polypropylenes, polybutenes, olefin copolymers, resins styrenics, elastomers and their mixtures.

7. Multilayer according to any one of claims 1 to 6, characterized in that the surface layer is a polyolefin film having a thickness between 0.070 mm and 0.12 mm.

8. Multilayer according to any one of claims 1 to 7, characterized in that the composition of the main layer comprises compounds of vegetable origin, advantageously starch.

9. A method for manufacturing the multilayer according to any one of claims 1 to 8, comprising the preparation of a laminate comprising a main layer, a surface layer and a protective layer, the main layer having a lower face FICP and a top face FSCp, the surface layer having a lower face FICs opposite the top face FSCp of the main layer, and a top face FScs, the protective layer being deposited on the top face FSCs of the surface layer.

10. A method according to claim 9, characterized in that the main layer is extruded onto the surface layer, the surface layer being, prior to extrusion, a thermoplastic polymer film associated with the protective layer.

11. A method according to claim 9, characterized in that the main layer is extruded between the surface layer and a sub-layer, the surface layer being, prior to extrusion, a thermoplastic polymer film associated with the protective layer, the sub-layer being made of polyolefin foam.

12. A method according to claim 9, characterized in that the main layer is associated with an underlayer by direct calendering without glue or indirect calendering with glue, the underlayer being made of textile material or polyolefin foam.

13. A process according to any one of claims 9 to 12, characterized in that the main layer is prepared by extruding thermoplastic granules having a composition comprising: * at least 70% by mass of polyolefin, and * crosslinked polyurethane, having an average size of between 2 and 15 mm.

14. Use of the multilayer according to any one of claims 1 to 5, in the field of automotive or leather goods.