Multilayer comprising a main layer based on polyolefin

Abstract

The present invention relates to a multilayer comprising at least: a) a main layer having a composition, over its entire 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 field.

Description

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

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

[0002] In the automotive field, the functions of the dashboard and the 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, RPM being generally dark in color and not controlled in terms of shades. Thus, these new structures, due to their material design (presence of RPM), might not meet the expectations of designers. There is therefore a need to develop a technical sheet (multilayer made of polymer materials) in order to cover these structures and, consequently, have a satisfactory finish, for example light-colored, plain variants...

[0003] Another problem 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 for example overmolding (single-step process), display (Hot Melt bonding), thermocladding (display thermoforming 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, in particular due to the presence of polymers of different natures, or even incompatible with each other. Indeed, the different layers of the multilayers can be made up of polymers that are incompatible in the molten state, that is to say during the preparation of the layers, the association between the layers being ensured by an adhesive.

[0007] Furthermore, the properties of a layer comprising recycled materials are generally not satisfactory, and points of weakening may appear.

[0008] Consequently, there is a need to develop solutions that allow these large quantities of materials to be recycled without requiring prior sorting and therefore an additional energy and logistical constraint.

[0009] The present invention makes it possible to solve these problems (compatibility with a structure based on MPR, recycling of MPR in a multilayer) by integrating within a multilayer a specific layer based on polyolefin and advantageously crosslinked 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 FICP lower face and an FSCp upper face, the main layer having a thickness of between 0.2 and 2.2 mm and a grammage of between 150 and 2100 g / m2, the main layer having a composition, over its entire thickness, comprising: * at least 70% by mass of polyolefin, and * advantageously crosslinked polyurethane, (b) a surface layer having a thickness less than or equal to 0.12 mm and a weight less than 110 g / m2, the surface layer being a thermoplastic polymer film, preferably chosen from: polyolefin; polyurethane and their mixtures, the surface layer having a lower face FICs opposite the upper face FS Cp 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 crosslinked polyurethane and having a polyurethane weight of between 1 and 25 g / m2.

[0012] The expression "facing" 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 glue dots.

[0013] Undercoat

[0014] According to a particular embodiment, the multilayer also comprises a sub-layer, opposite the lower face FICP of the main layer.

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

[0016] Thus, the multilayer may comprise a sub-layer made of textile material (for example a jersey, a three-dimensional textile, a non-woven fabric, etc.) which is glued to the lower FICp face of the main layer. In this case, the sub-layer has a thickness advantageously between 0.1 and 6 mm and a weight advantageously between 30 and 300 g / m2.

[0017] The multilayer may comprise a polyolefin foam underlayer, which is advantageously extruded or bonded to the FICP underside of the main layer. In this case, the underlayer has a thickness advantageously between 1 and 6 mm, preferably 1.5 to 3 mm, and a density advantageously 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 sub-layer having a lower face FISCm covered with a layer based on crosslinked polyurethane 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, over 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 comprises a textile underlayer, the main layer advantageously comprises at least 70% by mass of polyolefin.

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

[0022] Advantageously, the main layer has a density of 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 grammage 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 weight of between 400 and 800 g / m2 and a thickness of between 0.45 and 0.90 mm, for example a 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 crosslinked polyurethane.

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

[0028] Generally, the composition of the main layer may comprise compounds of plant origin, for example starch.

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

[0030] The 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 in the main layer are commonly used due to their lightness and versatility.

[0033] Thus, the main layer advantageously comes, in part or entirely, from the recycling of polyolefin foam and varnished polyolefin films, the varnish being made of crosslinked polyurethane.

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

[0035] The present invention therefore 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 compatibilizing agent between the polyolefin and the crosslinked polyurethane. Surface layer

[0036] As already indicated, the multilayer comprises a surface layer having a lower face FICs facing 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 grammage 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 chosen from: polyolefin; polyurethane; and mixtures thereof.

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

[0041] As already indicated, the multilayer comprises a protective layer opposite the upper face FSCs of the surface layer.

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

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

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

[0045] According to another particular embodiment, the multilayer comprises (advantageously consists 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, - foam underlayer.

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

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

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

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

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

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

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

[0053] The present invention also relates to a method for manufacturing the multilayer. This method comprises preparing a laminate comprising a main layer, a surface layer and a protective layer, the main layer having a lower face FICp and an upper face FSCp, the surface layer having a lower face FICs facing the upper face FS Cp 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 into 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 film of thermoplastic polymer (advantageously 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 associated with the main layer by calendering.

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

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

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

[0062] The composition of the thermoplastic granules may 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 field. Examples

[0064] The following multilayer was prepared as follows: - Application of a layer of varnish (5g / m2 of crosslinked polyurethane) on a foam underlayer (crosslinked polyolefin), - Deposit of a protective layer (2x5g / m2 of crosslinked polyurethane) on a surface layer of polyolefin (80 g / m2, 85pm), - Extrusion of the main layer (220°C, 370 g / m2, 500pm) between the surface layer (polyethylene / polypropylene multilayer + 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 (including 4.5% of crosslinked polyolefin) and 1% of crosslinked polyurethane; 20% by mass of the main layer being of recycled origin.

Claims

Claims

1. 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 weight of between 150 and 2100 g / m2, the main layer having a composition, over its entire 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 weight of less than 110 g / m2, the surface layer being a thermoplastic polymer film, preferably chosen from: polyolefin; polyurethane and their mixtures, the surface layer having a lower face FICs facing the upper face FSCp of the main layer, and an upper face FSCs, c) a protective layer facing the upper face FSCs of the surface layer, the protective layer being based on crosslinked polyurethane and having a polyurethane weight of between 1 and 25 g / m2.

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

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

4. Multilayer according to one of claims 1 to 3, characterized in that the multilayer comprises a polyolefin foam sub-layer having a lower face FIScm covered with a layer based on crosslinked polyurethane and an upper face FSscm advantageously facing the lower face FICp of the main layer.

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

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

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

9. A method of manufacturing the multilayer according to 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 an upper face FSCP, the surface layer having a lower face FICs facing 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.

10. 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. 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. Method according to claim 9, characterized in that the main layer is associated with a sub-layer by direct calendering without glue or indirect with glue, the sub-layer being made of textile material or polyolefin foam.

13. Method according to one of claims 9 to 12, characterized in that the main layer is prepared by extrusion of 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 one of claims 1 to 5, in the automotive or leather goods field.