Laminated part for thermoforming

Abstract

A laminated part comprising at least the following layers of materials, stacked in this order: - a layer of thermoplastic polymer with a density ranging from 0.5 to 1.5; - a first layer of a first hot-melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C; - a filling layer with a density ranging from 11 kg / m³ to 200 kg / m³, preferably from 30 kg / m³ to 90 kg / m³, made of a material selected from fibrous and cellular materials; - a second layer of a second hot-melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C; - a layer of textile with a basis weight between 30 g / m² and 1500 g / m², a process for preparing this part and its use for manufacturing cladding elements for Vehicles, interior design. Figure to be published with the abbreviation: none

Description

Title of the invention: Laminated part for thermoforming

[0001] The invention relates to the field of trim elements, particularly for vehicles for the transport market, such as dashboards, interior trim elements; for the building market, particularly interior fittings, furniture; for luggage, particularly internal surfaces of luggage items.

[0002] More particularly, the invention relates to the manufacture of relatively rigid articles having a surface with a particular appearance, such as a soft touch imparted by a fabric or any other coating, such as a coated, waterproof, washable fabric, or any material compatible with said technology. The decorative surface may have moderate compressive strength and resilience in order to give it a soft and comfortable feel.

[0003] Typically, such trim items are produced by injection molding. Indeed, this technology has the advantage of allowing the manufacture of complex-shaped parts at a rapid rate; however, the costs associated with implementing injection molding processes can be prohibitive, particularly when the objective is the production of small or medium series of items.

[0004] Thermoforming is a simpler and less expensive process than injection molding; however, the constraints associated with implementing thermoforming processes meant that they did not seem suitable for shaping heterogeneous multilayer parts. Furthermore, thermoforming does not always allow for the production of parts that are both complex and large.

[0005] In particular, one of the problems at the origin of the invention was the difficulty in assembling elements in the form of very heterogeneous layers, in order to obtain an assembly suitable for thermoforming to lead to a finished article that is stable over time.

[0006] French patent application FR 3 079 448 Al already describes laminated parts, however these parts do not comprise the same layers as the laminated parts according to the present invention, in addition the finished articles described in this prior art document are not manufactured by a thermoforming process of said laminated part.

[0007] Surprisingly and advantageously, the inventors have implemented a particular multilayer part suitable for use in the manufacture, by thermoforming, of a covering element meeting the structural requirements at the basis of the invention in particular comprising a filling element and a soft or decorative touch surface.

[0008] A first object of the invention relates to a laminated part comprising at least the following layers of materials, stacked in this order: -a layer of thermoplastic polymer with a density ranging from 0.5 to 1.5; -a first layer of a first hot-melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C, -a filling layer with a density ranging from 11 kg / m3 to 200 kg / m3, preferably from 30 kg / m3 to 90 kg / m3, made of a material chosen from fibrous and cellular materials, - a second layer of a second hot-melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C, -a layer of textile with a weight between 30g / m2 and 1500 g / m2.

[0009] Said part is suitable for use in a thermoforming process.

[0010] The laminated part according to the invention comprises, in particular, a padding layer made of a material selected from fibrous and cellular materials, located near a thermoplastic layer. These layers are generally insulating. These insulating layers constitute airtight barrier layers that prevent the transfer of heat / calories through the padding to the interior of the part. Surprisingly, it has been shown that a hot-melt adhesive can be advantageously used to bond the layers of the laminated part cohesively and without affecting the external surface of the textile layer, in particular without any surface defects.

[0011] The laminated part according to the invention also has the advantage of being able to be molded by thermoforming, that is to say that its structure allows adequate sliding of the different layers during forming in a mold without loss of cohesion of its general structure in particular in delamination of layers.

[0012] The final part obtained by thermoforming the laminated part according to the invention is stable over time under normal conditions of use, in particular in terms of exposure to heat and UV.

[0013] A second object of the invention relates to a method for manufacturing the laminated part according to the invention comprising at least the following steps: -a bonding step, using the first hot melt adhesive, of the first face of the filler material layer onto one face of the thermoplastic polymer layer, -a step of bonding, using the second hot melt adhesive, one side of the textile layer to the second side of the filling material layer.

[0014] The process according to the present invention makes it possible to manufacture large parts, in fact parts with a surface area of ​​up to 3.5 m X 2.5 m can be produced.

[0015] A third object of the invention relates to the uses of the part according to the invention in or for the manufacture of a trim element for vehicles for the transport market such as, for example, dashboards, interior trim elements, for the building market in particular interior design, furniture, for luggage in particular the internal surfaces of luggage items.

[0016] The invention also relates to the following variants. Those skilled in the art will understand that each of the features of the following variants can be combined independently with the above features, without thereby constituting an intermediate generalization.

[0017] According to one embodiment, the filling material is chosen from polyolefin foams, polyester fibers, cotton felts, melamine foams, polyurethane foams, preferably it is chosen from cross-linked polyethylene (PER) foams with a density ranging from 30 kg / m3 to 90 kg / m3.

[0018] According to one embodiment, the first and second hot melt adhesives, identical or different, are chosen from copolyamides, copolyesters, polyurethanes (PU), polyethylenes (PE) and ethylene vinyl acetate (EVA), preferably chosen from copolyamides.

[0019] According to one embodiment, the thermoplastic polymer layer is a layer of a material selected from acrylonitrile butadiene styrene (ABS), polystyrene (PS), poly(methyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).

[0020] According to one embodiment, the thermoplastic polymer layer is such that its face in contact with the first hot melt adhesive has asperities in particular a graining.

[0021] According to one embodiment, the textile layer exhibits elongations along its two principal directions of between 5 and 200% regardless of the standard applied.

[0022] Definitions

[0023] By “layered part” we mean an object having several superimposed layers assembled together.

[0024] In the present text, intervals are defined abbreviatedly to avoid describing each and every value within the interval; however, any suitable value within the interval may be chosen as the upper, lower, or terminal values ​​of the interval. An interval defined as being "between value A and value B" includes the values ​​A and B and is therefore equivalent to an interval "from value A to value B". Furthermore, the expression "At least" includes the value stated after it; for example, "at least 5%" should be understood as also including "5%". The expression "a maximum of" includes the value stated after it; for example, "a maximum of 5%" should be understood as also including "5%".

[0025] Furthermore, in the present text, measurable values, such as a quantity, should be understood as including standard deviations that can be readily determined by a person skilled in the art in the relevant technical field.

[0026] Generally, the laminated parts according to the present invention have a thickness ranging from 1 mm to 30 mm.

[0027] In general, the laminated parts according to the present invention have a surface having a first side ranging from 0.05 m to 3.5 m and a second side ranging from 0.05 m to 2.5 m. Detailed description

[0028] Other features and advantages of the invention will become clear from the detailed description given below, which is by way of example and not limitation.

[0029] Thermoplastic polymer

[0030] The laminated part according to the present invention comprises a layer of thermoplastic polymer with a density ranging from 0.5 to 1.5.

[0031] This layer, intended to constitute the internal surface of the finished article, i.e. the face not visible when the article is assembled for its final use, makes it possible to give rigidity and strength to the laminated part.

[0032] This layer has the advantage of being able to be softened during the manufacturing stage of the laminated part and then during the heating stage of thermoforming and to regain its appearance and properties in particular of rigidity after cooling.

[0033] According to a particular embodiment, the thermoplastic polymer layer is a layer made of a material selected from acrylonitrile butadiene styrene (ABS), polystyrene (PS), poly(methyl methacrylate (PMMA), polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).

[0034] Generally the thermoplastic polymer layer has a thickness ranging from 1 mm to 10 mm, preferably from 3 to 8 mm.

[0035] Filling layer

[0036] The laminated part according to the present invention comprises a filling layer of a material with a density between 11 kg / m3 and 200 kg / m3, preferably between 30 kg / m3 and 90 kg / m3 and even more preferably between 50 kg / m3 and 90 kg / m3 chosen from fibrous materials and cellular materials.

[0037] This padding layer, also called the comfort layer, provides the user with cushioning upon contact and a pleasant feel. In addition, some paddings have the property of being thermo-compressible and therefore leading to thinner filling layers in places, thus allowing surfaces to be animated.

[0038] The padding layer is preferably made of a material chosen from polyolefin foams, in particular polyethylene, polyester fibers, cotton felts, melamine foams, polyurethane foams.

[0039] According to a preferred method, the filling layer is made of a material selected from cross-linked polyethylene or PER foams with densities ranging from 30 kg / m3 to 90 kg / m3. For example, PER foam marketed under reference NT 2003 by the company Alvéo may be cited.

[0040] PER has a structure in which the cells forming the foam are closed, which gives the filling layer insulating and airtight properties that are particularly advantageous for the final article.

[0041] Generally the filling layer has a thickness ranging from 1 to 20 mm, preferably from 1 to 5 mm.

[0042] Textile layer

[0043] The laminated part according to the present invention advantageously comprises a layer of textile having elongations along its two principal directions of between 5 and 200% and a weight of between 30g / m2 and 1500g / m2.

[0044] According to a first embodiment, the textile is a knitted fabric made of natural or synthetic yarns having elongations at 35 N in its two principal directions ranging from 10 to 200% according to ISO 13934-1:2013 and a basis weight of between 50 and 500 g / m². For example, the Moritz knit fabric from Sofileta comprises 56% PET, 36% PA, and 8% EA, with a basis weight of 170 g / m².

[0045] According to a second embodiment, the textile is a plastic-coated fabric (TEP), with or without a coating base, having elongations at 35 N in its two principal directions of between 5 and 50% according to ISO 13934-1:2013 and a basis weight of between 250 and 1500 g / m². For example, Continental's Nappa fabric may be cited.

[0046] According to a third embodiment, the textile is a non-woven fabric having elongations in its two principal directions of between 5 and 100% according to ISO 9073-3 of December 1992 and a basis weight of between 30 and 500 g / m2. As an example, the Aquadim BK40 product from Fibertex may be cited.

[0047] Generally the textile layer has a thickness ranging from 0.4 mm to 3 mm.

[0048] Hot melt adhesive

[0049] The laminated part according to the present invention comprises at least two layers of hot melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C.

[0050] The first layer of a first hot melt adhesive is located between the thermoplastic polymer layer and the filler layer.

[0051] The second layer of a second hot melt adhesive is located between the filling layer and the textile layer.

[0052] The first and second adhesives may be identical or different.

[0053] Preferably, the first and second hot melt adhesives, identical or different, are chosen from copolyamides, copolyesters, polyurethanes (PU), polyethylenes and ethylene vinyl acetate (EVA), preferably they are chosen from copolyamides.

[0054] According to a particular embodiment, the first adhesive may comprise two parts, one applied to the thermoplastic polymer layer and the other applied to the filler layer. The nature of these parts or sub-layers depends, in particular, on the durability required by the end use. Specifically, when the final article is intended for interior furnishings, the durability requirements are less stringent than for an article intended for vehicles, which is subjected to greater stresses such as temperature variations and UV exposure.

[0055] For a furniture article, an adhesive comprising two parts or sub-layers can be used as a first adhesive, a polyamide sub-layer applied to the thermoplastic polymer layer and a polyurethane sub-layer applied to the padding layer.

[0056] For an article intended for vehicles, an adhesive comprising two identical parts or sub-layers can be used as a first adhesive, a polyamide sub-layer applied to the thermoplastic polymer layer and another polyamide sub-layer, identical or different, applied to the filler layer.

[0057] Hot melt adhesives, when applied, can be in the form of veils or in the form of films.

[0058] Advantageously, hot melt adhesives in the form of a veil or spider web, also called a web in English, are preferred. For example, the CoPA 178D20 product from Protechnic can be cited.

[0059] As an example of a hot melt adhesive in film form, we can mention the product Film TC 204 from the company Prochimir.

[0060] Preparation process

[0061] The manufacturing process for the laminated part according to the invention involves at least two bonding steps using at least one hot melt adhesive with a melting temperature ranging from 60°C to 170°C, preferably from 90°C to 130°C.

[0062] The bonding steps of the different layers are carried out by depositing / anchoring the hot melt adhesive on one of the surfaces of a layer of one material and then applying one of the surfaces of a layer of another material.

[0063] According to one embodiment, the process according to the invention comprises at least the following steps: -a bonding step, using the first hot melt adhesive, of the first face of the filler material layer onto one face of the thermoplastic polymer layer, -a step of bonding, using the second hot melt adhesive, one side of the textile layer to the second side of the filling material layer.

[0064] Preferably, the step of bonding the filler material layer to the thermoplastic polymer layer is carried out according to the following steps: - a step of depositing a first hot-melt adhesive on one face of the thermoplastic polymer layer, -a step of depositing the first hot melt adhesive on the first face of the layer of filling material; -these two steps being followed by a step of bringing the hot melt adhesive deposited on the thermoplastic polymer layer into contact with the hot melt adhesive deposited on the layer of filling material.

[0065] The process according to the invention is implemented by means of any suitable device to assemble the layers by pressing them together while heating them simultaneously.

[0066] The laminated part suitable for use in a thermoforming process is advantageously flat.

[0067] According to a particular embodiment, a continuous flatbed gluing press of the MEYER type can be used, in particular a roller press equipped with heating means, specifically equipped with upper and lower belts and several systems of two parallel and counter-rotating rollers where two layers are superimposed, compressed, and heated. This pressing is also called lamination; it is further carried out by applying a heating temperature higher than the melting temperature of the adhesive. The heating can be provided by a heating device positioned near the layer to be heated or by heated rollers.

[0068] The following examples illustrate the invention without limiting its scope. EXAMPLES

[0069] Examples 1 to 3 below were implemented using a roller press according to the following 3 steps named A, B and C.

[0070] Step A:

[0071] During this step, the following roll materials were used: -on the one hand, at the top, the filling layer and a hot melt adhesive veil corresponding to the first hot melt adhesive according to the present invention, on the filling layer, at this stage, the first hot melt adhesive is anchored on the filling layer, it is then used for bonding during step C; -on the other hand, at the bottom, the textile layer and a layer of hot melt adhesive corresponding to the second hot melt adhesive according to the present invention, on the textile layer.

[0072] During this step A, the materials were unrolled and the following stack was formed: textile layer / second hot melt adhesive / scrim layer / part (sub-layer a) of the first hot melt adhesive layer.

[0073] Step B:

[0074] During this step, layers of the following materials were used: -on the one hand, at the top, a roll of hot melt adhesive corresponding to the first hot melt adhesive according to the present invention. -on the other hand, at the bottom, the layer of thermoplastic polymer in sheet form.

[0075] During this step B, the following stack was formed: thermoplastic polymer layer / a part (sub-layer b) of the first hot melt adhesive layer.

[0076] Step C:

[0077] During this step, the stack formed in step A was unrolled at the top onto the stack formed in step B by bringing the two parts (sub-layers a and b) of the layer of the first hot melt adhesive into contact.

[0078] During this step C, by heating, the following stack was formed: textile layer / second hot melt adhesive / filling layer / (sub-layers a and b) of the first hot melt adhesive layer / thermoplastic polymer layer.

[0079] In the following tables, the materials have been named "top material" and "bottom material", and the heating devices intended to heat the "top material" and "bottom material" respectively have been named "top heater" and "bottom heater".

[0080] The laminated parts of examples 1 to 3 were made with the materials shown respectively in tables 1 to 3.

[0081] Example 1

[0082] Example 1 was made with a layer of ABS as the thermoplastic polymer, a PER as the filling and a mesh fabric.

[0083] [Tables 1] Example Step A Step B Step C Top Material Cross-linked polyethylene foam NT 2003 from Alvéo + Web COPA 178 D20 adhesive from Protechnic. First heat-fusible adhesive: Web COPA 178D20 from Protechnic. System A Bottom Material Moritz fabric (56% PET; 36% PA; 8% EA) + Web COPA 178D20 from Protechnic. 4 mm ABS, grained side. System B Top heating temperature 140°C 160°C 200°C Bottom heating temperature 140°C 110°C 160°C Pressure 45N / cm² 45N / cm² 45N / cm² Speed ​​4 m / min 3 m / min 1 m / min

[0084] Example 2

[0085] Example 2 was made with a layer of ABS as the thermoplastic polymer, a PER as the filling and a TEP fabric.

[0086] [Tables2] Example System A System B System C Top Material Cross-linked polyethylene foam NT 2003 from Alvéo + Web CO PA 178D20 from Protechnic Premier thermally fused adhesive + TC 204 film from Prochimir System A Bottom Material TEP Nappa fabric from Contin entai thermally fused adhesive 178D20 from Protechnic 3 mm textured ABS System B Top heating temperature 140°C 160°C 150°C Bottom heating temperature 140°C 110°C 160°C Pressure 45N / cm² 45N / cm² 45N / cm² Speed ​​4 m / min 3 m / min 0.5 m / min

[0087] Example 3

[0088] Example 3 was made with a layer of PS as the thermoplastic polymer, a PER as the filling and a mesh fabric.

[0089] [Tables3] Example Step A Step B Step C Top Material Cross-linked polyethylene foam NT 2003 from Alvéo + Web COPA 178 D20 adhesive from Protechnic. First heat-fusible adhesive: Web COPA 178D20 from Protechnic. System A Bottom Material Moritz fabric (56% PET; 36% PA; 8% EA) + Web COPA 178D20 from Protechnic. 3 mm PS grain side. System B Top heating temperature 140°C 160°C 200°C Bottom heating temperature 140°C 110°C 160°C Pressure 45N / cm² 45N / cm² 45N / cm² Speed ​​4 m / min 3 m / min 1 m / min

[0090] Example 4

[0091] Example 4 was made with a layer of ABS as the thermoplastic polymer, a PU foam as the filling and a non-woven fabric with a single pass.

[0092] [Tables4] Example System A Top Material: Aquadim BK 40 1 78D20 Polyurethane foam with a density of 30 kg / m³ + 6C8D30 from Protechnique Bottom Material: 3 mm ABS Top Heating Temperature: 200°C Bottom Heating Temperature: 160°C Pressure: 45 N / cm² Speed: 0.5 m / min

[0093] For each of these examples, the set of layers of the resulting laminated part is cohesive, the surface condition of the textile layer shows no deformation: the elongation of the textile allows a conformal deformation of the laminated part.

[0094] Thermoforming of laminated parts

[0095] The thermoforming of the laminated parts of examples 1 to 4 was carried out in a Geiss type apparatus.

[0096] The heating steps were carried out according to the operating conditions of temperature, time presented in Table 5 below.

[0097] Then the molds were made with a hollow mold, under vacuum (100%).

[0098] The thermoformed parts were then cooled by a forced air system and by heating the mold to 60°C (thermal regulation circuit)

[0099] [Tables5] Step 1: Upper heating temperature. Step 1: Lower heating temperature. Step 1: Heating time. Example 1: 400°C - 200°C - 280 sec. Example 2: 380°C - 180°C - 280 sec. Example 3: 400°C - 200°C - 220 sec. Example 4: 400°C - 80°C - 450 sec.

[0100] The results obtained are satisfactory: the thermoformed articles are cohesive, without delamination. The padding layer appears to be of uniform thickness without significant compression. The PU padding layer in Example 4 is not compressible, unlike the PER padding layer in the other examples. The textile surface does not appear altered, without significant creases.

[0101] Example 1 was also reproduced with a slower 15% vacuum molding process, and the result was unchanged.]

Claims

Demands

1. A laminated part comprising at least the following layers of materials, stacked in this order: - a layer of thermoplastic polymer with a density ranging from 0.5 to 1.5; - a first layer of a first hot-melt adhesive with a melting temperature ranging from 90°C to 130°C; - a filling layer selected from cross-linked polyethylene foams with a density ranging from 30 kg / m³ to 90 kg / m³; - a second layer of a second hot-melt adhesive with a melting temperature ranging from 90°C to 130°C; - a textile layer with a basis weight between 30 g / m² and 1500 g / m².

2. ni. Laminated part according to claim 1 in which the first and second hot melt adhesives, identical or different, are selected from copolyamides, copolyesters, polyurethanes, polyethylenes and ethylene vinyl acetate, preferably selected from copolyamides.

3. A laminated part according to any one of claims 1 or 2 wherein the thermoplastic polymer layer is a layer of a material selected from acrylonitrile butadiene styrene, polystyrene, poly(methyl methacrylate), polyethylene, polypropylene and polyvinyl chloride.

4. A laminated part according to claim 3 in which the thermoplastic polymer layer is such that its face in contact with the first hot melt adhesive has asperities in particular a graining.

5. A laminated part according to any one of the preceding claims in which the textile layer has elongations along its two principal directions of between 5 and 200%.

6. A laminated part according to any one of claims 1 to 5 wherein the textile layer is a mesh fabric having elongations at 35 N along its two principal directions of between 10 and 200% according to ISO 13934-1 of 2013 and a basis weight of between 50 and 500 g / m2.

7. A laminated part according to any one of claims 1 to 5, wherein the textile layer is a plastic-coated fabric, with or without coating, exhibiting elongations at 35 N along its two principal directions between 5 and 50% according to ISO 13934-1 of 2013 and a basis weight between 250 and 1500 g / m2.

8. A laminated piece according to any one of claims 1 to 5 in which the textile layer is a non-woven fabric having elongations in its two principal directions of between 5 and 100% according to ISO 9073-3 of December 1992 and a basis weight of between 30 and 500 g.

9. A method for manufacturing the laminated part according to any one of the preceding claims characterized in that it comprises at least the following steps: - a step of bonding, using the first hot melt adhesive, the first face of the layer of filling material to a face of the thermoplastic polymer layer, - a step of bonding, using the second hot melt adhesive, one face of the textile layer to the second face of the layer of filling material.

10. A method for manufacturing the laminated part according to the preceding claim, characterized in that the step of bonding the layer of filler material to the layer of thermoplastic polymer is carried out according to the following steps: - a step of depositing a first hot melt adhesive on one face of the layer of thermoplastic polymer, - a step of depositing a first adhesive on the first face of the layer of filler material; - these two steps being followed by a step of bringing the hot melt adhesive deposited on the layer of thermoplastic polymer into contact with the hot melt adhesive deposited on the layer of filler material.Use of the laminated part according to any one of claims 1 to 8 or obtained according to the manufacturing process according to claim 9 or 10 in or for the manufacture of a trim element for vehicles for the transport market such as, for example, dashboards, interior trim elements, for the building market in particular interior design, furniture, for luggage in particular the internal surfaces of luggage items.