Composition for a multilayer structure based on polyamide usable as a card

Abstract

Composition for a polyamide-based multilayer structure usable as a card. The present invention relates to a composition comprising a polyamide matrix predominantly composed of at least one polyamide having a C / N ratio greater than or equal to 8 and 5 to 20% by weight of a reinforcing filler having an aspect ratio between 2 and 9. The invention also relates to a method for preparing a film of said composition. The invention further relates to a structure that can be used as a data-carrying card, such as a card to secure an electronic identity, a bank card, an identity card, a smart card, a card to control access to a space, such as a building, a room, an entry vestibule, an elevator, a storage space such as a cabinet, a drawer, a safe, or a card to control networks and computers.

Description

Title of the invention: Composition for a polyamide-based multilayer structure usable as a card technical field

[0001] The present invention relates to a composition for a multilayer structure usable as a card, as well as its manufacturing process. Technical background

[0002] Smart cards provide a structure for securing an electronic identity. They can be used to control access to buildings, networks, and computers. They are also used as national identity cards, thus authenticating their owner. These cards contain data that is either visibly represented by ink or engraving, or invisibly represented by an electronic chip, antenna, magnetic stripe, or other device.

[0003] Currently, the cards offered are made of PVC. This material is obtained through a relatively toxic synthesis process and has the disadvantage of being difficult to recycle. Therefore, less polluting and recyclable materials are being sought to manufacture these cards.

[0004] The use of polyamides to manufacture cards is known from documents US2021 / 0268823 and US2022 / 0363953. Technical problem to solve

[0005] However, the materials sought must meet specific requirements. Ideally, they should be able to replace PVC in the card manufacturing process without any modification to the process itself. This process uses film manufacturing steps, followed by hot compression of these films to ensure adhesion between the layers and the shaping of the object into a card.

[0006] One of the challenges in choosing the material relates to the difference in rigidity between PVC and polyamides, particularly long-chain polyamides. Indeed, it is necessary to guarantee good product durability over time, low deformation during use, and a certain level of mechanical rigidity in the core layers of the object.

[0007] Next, the films produced must have the same surface appearance and dimensional and structural quality as objects made of PVC.

[0008] The addition of fillers to polyamides is known. However, the possibility of manufacturing films with dimensions between 150 and 450 µm, without structural and / or dimensional defects, is not yet established. Furthermore, the raw material must be easy to implement in a film manufacturing process, particularly an extrusion-cast process.

[0009] The technical problem is therefore to propose a composition enabling the production of polyamide films, particularly long-chain films, resulting in a film with a thickness between 150 and 450 µm, rigid and free of defects in cash extrusion

[0010] Thus, a specific polyamide-based composition has been found which makes it possible to manufacture films that meet criteria of rigidity, recyclability and which lead to parts without surface defects. Brief description of the invention

[0011] The present invention relates to a composition comprising

[0012] -a polyamide matrix comprising predominantly at least one polyamide having a C / N ratio greater than or equal to 8 and

[0013] -from 5 to 20% by weight of a reinforcing load having a shape factor between 2 and 9.

[0014] The invention also relates to an extrusion-cast process which implements the composition according to the invention.

[0015] The invention also relates to a multilayer structure comprising at least one layer made up of a composition as defined above.

[0016] The invention also relates to a method for preparing a film of composition as defined above, comprising the following successive steps: -an extrusion step through a flat die of the composition as defined above in the molten state, -a stretching step in air of the molten material, -a cooling step on a thermostatically controlled roller.

[0017] The invention also relates to the manufacturing process of the structure as defined above, comprising the following successive steps: l. at least one extrusion step of each of the structural components in film form, 2. at least one step of stacking the films on top of each other, 3. at least one compression step, 4. at least one cooling stage of the structure, possibly under pressure.

[0018] The invention also relates to the use of the structure as a card carrying data, such as a card to secure an electronic identity, a bank card, an identity card, a smart card, a card to control access to a space, such as a building, a room, an entrance vestibule, an elevator, a room, such as a storage space like a cabinet, a drawer, a safe, a card to control networks and computers.

[0019] The structure according to the invention has the advantage of being mechanically recyclable. There is no need to sort the polymers. The resulting mixture can be directly recycled either for the same application or for another application.

[0020] Indeed, the composition resulting from the recycling of the structure according to the invention comprises mainly one or more polyamides, and fillers. Indeed, the structure can be melted down and then reused to manufacture another object, whether by a molding process or by an injection or extrusion process.

[0021] Furthermore, when the structure consists mainly or exclusively of PA 11 as the matrix of the outer, intermediate, and central layers, the structure is predominantly bio-based. Its environmental impact is low compared to raw materials of fossil origin.

[0022] Other advantageous characteristics of the composition according to the invention are specified below. -The composition has a Young's modulus measured according to ISO 527-1A 2019 of between 1.8 and 4 GPa, preferably between 2 and 3.5 GPa.

[0023] -The composition has an MFI measured according to ASTM 1238-2020 at 235°C and 2.16 kg between 0.4 and 15 g / 10min, preferably 0.4 and 10 g / 10min.

[0024] -The polyamide matrix comprises at least one polyamide selected from PAU, PA12, PA1010, PA 1012, PA 513, PA 516, PA 612, PA613, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014, MXD10, MXD12, MXD13, PA10 / 11T, and mixtures thereof.

[0025] -The polyamide matrix comprises at least one polyamide selected from PAU, PA12, PA1O and PA1012.

[0026] -The reinforcing filler is chosen from calcium carbonate, silicas, quartz, diatomaceous earth, wollastonites, aluminosilicates, such as kaolin, magnesia, slag, slate flour, vermiculite, mica, fibers, preferably ground, preferably ground glass fibers, aramid fibers, glass flakes, glass beads, talc, carbon fillers, such as graphite, expanded graphite, carbon black, nanofillers, metal oxides, such as titanium oxide, most preferably talc and ground fibers.

[0027] -The largest dimension of the charge is less than 100 pm, preferably less than 50 pm.

[0028] -The filler is talc.

[0029] -The composition includes at least one reinforcing filler in a content ranging from 7 to 17% by weight relative to the total weight of the composition.

[0030] The composition is in the form of a film with a thickness between 100 and 450 pm.

[0031] Other advantageous features of the structure according to the invention are specified below.

[0032] -Said layer constitutes the central layer and / or at least one intermediate layer of the structure.

[0033] -The structure comprises at least one outer layer made up of a composition comprising a polyamide matrix, the outer composition having a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011.

[0034] -The structure comprises:

[0035] -an outer layer made of a composition comprising a polyamide matrix, the outer composition having a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011,

[0036] -an intermediate layer made of a composition as described above,

[0037] -a central layer made of a composition as described above,

[0038] -an intermediate layer made of a composition as described above,

[0039] -an outer layer made of a composition comprising a polyamide matrix, the outer composition having a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011,

[0040] the compositions constituting the outer layers, the intermediate layers and the central layer having a melting temperature greater than 150°C, preferably greater than 160°C. Detailed description

[0041] Other features, aspects, objects and advantages of the present invention will become even clearer upon reading the following description.

[0042] Unless otherwise stated, all percentages are mass percentages.

[0043] In this text, the quantities indicated for a given species may apply to that species according to all its definitions (as mentioned in this text), including more restricted definitions.

[0044] It is specified that the expressions "from ... to ..." and "between ... and ..." used in this description should be understood as including each of the limits mentioned.

[0045] The shape factor corresponds to a dimensionless variable allowing comparison of the various loads with each other.

[0046] Polyamides

[0047] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art. Thus, PA11 means that it is obtained by polycondensation of 11-aminoundecanoic acid. PA12 is obtained by polycondensation of lauryllactam. PA1010 is obtained by polycondensation of decanediamine (10) and decanedioic acid (10). PA1012 is obtained by polycondensation of decanediamine (10) and dodecanedioic acid (12).

[0048] The word "polyamide" covers both homopolyamides and copolyamides.

[0049] The invention is now described in more detail and in a non-limiting manner in the following description.

[0050] Polyamides are obtained by a polycondensation reaction of monomers, which may be amino acids or lactams, denoted Z, or chains of diacids and diamines, denoted XY, where X designates a diamine and Y designates a diacid. Thus, an amide function is indeed formed by the reaction of an amine function with an acid function.

[0051] By unit, for the purposes of the present invention, means a Z or XY link resulting from the polycondensation of monomers.

[0052] By motif, we mean in the context of the present invention the sequence Z or the sequence X or the sequence Y. In other words, the unit Z consists of a motif Z and the unit XY consists of a motif X and a motif Y.

[0053] By C / N ratio, we mean in the context of the present invention the average number of carbon atoms per nitrogen atom per unit.

[0054] In the case of a PA Z type homopolyamide, where Z designates a motif obtained from an amino acid or a lactam, the number of carbon atoms per nitrogen atom is the number of carbon atoms in the motif. For example, PA 11 obtained by polycondensation of 11-aminoundecanoic acid has a C / N ratio of 11.

[0055] In the case of a PA XY type homopolyamide, where X designates a motif obtained from a diamine and Y designates a motif obtained from a diacid, the number of carbon atoms per nitrogen atom is the average of the number of carbon atoms present in the XY unit. For example, PA 612, obtained by polycondensation of hexanediamine, a C6 diamine, and dodecanedioic acid, a C12 diacid, has a C / N ratio of 9, calculated as follows: (6+12) / 2 = 9.

[0056] For copolyamides, for example with the structure XaYa / XbYb, the number of carbon atoms per nitrogen atom is calculated according to the same principle. The calculation is performed in molar proportion of the different amide units, that is to say, the XaYa and XbYb units. XbYb. Thus the coPA 10T / 106 containing 60% of 10T and 40% of 106 is in C8,6: 60%x[(10+8) / 2]+40%x[(10+6) / 2] = 8,6.

[0057] The composition

[0058] The composition comprises:

[0059] -a polyamide matrix comprising predominantly at least one polyamide having a C / N ratio greater than or equal to 8 and

[0060] -from 5 to 20% by weight of a reinforcing load having a shape factor between 2 and 9.

[0061] Preferably, the composition comprises 60% to 95% by weight relative to the total weight of the composition of at least one polyamide having a C / N ratio greater than or equal to 8.

[0062] Preferably, the composition has a Young's modulus measured according to ISO 527-1A 2019 of between 1.8 and 4 GPa, preferably between 2 and 3.5 GPa.

[0063] Preferably, the composition has an MFI between 0.4 and 15 g / 10min, the MFI being measured under the following conditions: 235°C and 2.16 Kg, preferably 0.4 and 10 g / 10min.

[0064] The polyamide present in the matrix of the composition of the central and / or intermediate layer is obtained by polycondensation of at least one motif chosen from an alpha,omega-aminocarboxylic acid in C8 to C18, a lactam in C8 to C12 and a unit (diamine in Ca).(diacid in Cb), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0065] The polyamide can be obtained by polycondensation of at least one lactam selected from pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0066] The polyamide present in the matrix of the composition of the central and / or intermediate layer can also be obtained by polycondensation of at least one amino acid chosen from 9-aminononanoic acid, 10-aminodecanoic acid (denoted 10), amino-11-undecanoic acid (denoted 11), amino-12-dodecanoic acid (denoted 12).

[0067] Polyamide can be obtained by polycondensation of at least one motif corresponding to the formula (diamine in Ca).(diacid in Cb), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0068] The motif (diamine in Ca) may be aliphatic, cycloaliphatic, or aromatic. The diamine may be selected from butanediamine (a=4), pentanediamine (a=5), hexanediamine (a=6), heptanediamine (a=7), octanediamine (a=8), nonanediamine (a=9), decanediamine (a=10), undecanediamine (a=11), the dodecanediamine (a= 12), tridecanediamine (a= 13), tetradecanediamine (a= 14), hexadecanediamine (a= 16), octadecanediamine (a= 18), m-xylylene diamine (noted MXD), methylpentamethylene diamine (noted MPMD), bis(aminomethyl)cyclohexane (noted BAC), meta-xylylene diamine (MXD, CAS No.: 1477-55-0) and para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0069] Advantageously, diamine X is selected from 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0070] Preferably, diamine X is in C12 C10, in particular selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0071] The motif (Cb diacid) may be aliphatic, cycloaliphatic or aromatic. The diacid may be chosen from succinic acid (b=4), pentanedioic acid (b=5), adipic acid (b=6), heptanedioic acid (b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid (b=10), undecanedioic acid (b=11), dodecanedioic acid (b=12), brassylic acid (b=13), tetradecanedioic acid (b=14), hexadecanedioic acid (b=16), octadecanedioic acid (b=18) and diacids obtained from fatty acids, and terephthalic acid (denoted T).

[0072] Advantageously, the diacid is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0073] Advantageously, the polyamide present in the matrix of the composition of the central and / or intermediate layer is chosen from PAU, PA12, PA1010, PA 1012, PA 513, PA 516, PA 610, PA 612, PA613, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014, MXD10, MXD12, MXD13, PA 11 / 10T and their mixture.

[0074] According to a particular embodiment, the composition according to the invention comprises a mixture of aliphatic polyamide and aromatic polyamide, in which the aliphatic polyamide is the major polyamide.

[0075] According to a preferred embodiment, the polyamide present in the matrix of the composition of the central layer and / or the intermediate layer is a homopolyamide. This homopolyamide can be obtained by the polycondensation of a lactam, an amino acid, or a (Ca diamine) (Cb diacid) motif, with Ca and Cb being as defined above.

[0076] More particularly, the composition matrix mainly comprises PAU, PA 12, PA 1010, PA 1012, even more preferably PAU or PA 12, preferably PAU.

[0077] Preferably, the matrix of the composition comprises between 50% and 95% by weight of at least one polyamide relative to the total weight of the composition, preferably between 65% and 93%.

[0078] Charges

[0079] The composition according to the invention comprises one or more fillers having a form factor between 2 and 9, preferably between 2.5 and 7.

[0080] For the purposes of this invention, "shape factor" means the ratio of the largest dimension, for example the length, to the smallest dimension, for example the thickness, measured on the filler particle. The shape factor defines the shape of the filler within the composition.

[0081] Preferably, the fillers are chosen from calcium carbonate, silicas, quartz, diatomaceous earth, wollastonites, aluminosilicates, such as kaolin, magnesia, slag, slate flour, vermiculite, mica, fibers, preferably ground, preferably ground glass fibers, aramid fibers, glass flakes, glass beads, talc, carbon fillers, such as graphite, expanded graphite, carbon black, nanofillers, metal oxides, such as titanium oxide, most preferably talc and ground fibers.

[0082] According to a first preferred embodiment, the reinforcing filler is talc. The talc may be treated or untreated. Preferably, the talc is in lamellar form.

[0083] For example, lamellar talcs are defined by a particle size distribution. The d50 Sedigraph is measured by gravity sedimentation in a liquid according to ISO 13317-3:2001, for example in a Sedigraph III Plus® instrument. The d50 Laser is measured by laser diffraction according to ISO 13320:2009, for example on a Malvern Mastersizer 2000® diffractometer.

[0084] The d50 distribution measured by Sedigraph evaluates the smallest particle size. The d50 distribution measured by laser evaluates the largest particle size. Thus, the form factor for these charges is obtained by the ratio d50 laser / d50 Sedigraph.

[0085] The reinforcing fillers that may be included in the composition according to the invention are talc marketed under the trade name Jetfine® 3CA, lamellar talc marketed under the trade name HAR® W 92, lamellar talc marketed under the trade name HAR® T 84.

[0086] By way of example, Jetfine 3C talc has Sedigraph d50 values ​​of 1.0 pm and laser d50 values ​​of 3.9 pm, resulting in a form factor of 3.9. Jetfine 3CA talc has a form factor of 3.4. HAR T84 talc has Sedigraph d50 values ​​of 2.2 pm and laser d50 values ​​of 10.5 pm, resulting in a form factor of 4.8.

[0087] The "tapped bulk" density as defined by ISO 787 / 11 for talcs is between 0.7 and 1 g / cm3.

[0088] According to a second preferred embodiment, the reinforcing filler is a fiber, preferably ground fibers, most advantageously ground glass fibers.

[0089] For the purposes of this invention, glass fiber means any glass fiber, in particular as described by Frederick T. Wallenberger, James C. Watson and Hong Li, PPG industries Inc. (ASM Handbook, Vol 21: composites (#0678IG), 2001 ASM International).

[0090] Glass fibers generally have a diameter between 5 and 20 pm, preferably the diameter of the fibers is between 10 and 18 pm.

[0091] Standard glass fibers generally have lengths of several millimeters and, after compounding and extrusion, have average lengths of more than 200 µm. Thus, the shape factor for these fibers is obtained by the ratio of average length to diameter.

[0092] Preferably, the glass fibers of the invention are ground glass fibers, that is to say, glass fibers whose length before compounding and extrusion is less than 100 pm. After compounding and extrusion, these glass fibers therefore have an average length of less than 100 pm, preferably less than 50 pm.

[0093] Preferably, the glass fibers have an average length in the composition according to the invention, i.e. after grinding and after passing through the extruder, of between 30 and 100 pm, preferably, the length of the fibers is between 40 and 80 pm.

[0094] For example, the following commercial glass fibers can be used: Lanxess MF 7904 glass fiber with an average length of 50pm and an average diameter of 14pm.

[0095] Advantageously, the composition according to the invention comprises 5 to 20% by weight of a reinforcing filler having a shape factor between 2 and 9 and whose largest dimension is less than 100 pm, preferably less than 50 pm.

[0096] The composition constituting the central layer and / or an intermediate layer comprises 5 to 20% by weight of reinforcing fillers relative to the total weight of the composition, preferably between 7 and 17% by weight.

[0097] Additives

[0098] The composition according to the invention may comprise one or more additives selected from antioxidants, UV protectants, UV stabilizers, thermal stabilizers, lubricants, fluidity improvers, Flowability improvers, film-forming agents, film-forming aids, gums, preservatives, antibacterial agents, pigments and mixtures thereof. Preferably, the composition includes at least one heat stabilizer.

[0099] The composition may include from 0.4 to 5% by weight of additives relative to the total weight of the composition.

[0100] Preferably, the composition is in the form of a film with a thickness between 100 and 450 pm, preferably between 150 and 350 pm.

[0101] The central layer and the intermediate layer(s) each preferably have a thickness between 100 and 450 pm, advantageously between 150 and 350 pm. In particular, the thickness of the central layer depends on the object to be accommodated.

[0102] Preferably, the composition has a melting point above 150°C, preferably above 160°C.

[0103] The multilayer structure

[0104] The multilayer structure according to the invention comprises at least one layer made of a composition as described above.

[0105] The layer consisting of a composition such as described above can be the central layer of the structure, an intermediate layer of the structure, all the intermediate layers of the structure, or the central layer and all the intermediate layers of the structure.

[0106] The structure may comprise the following layers, according to this arrangement: -an outer layer

[0107] -an intermediate layer -a central layer -an intermediate layer -an outer layer.

[0108] The structure may also comprise the following layers, according to this arrangement: -an outer layer -a layer of binder -an intermediate layer -a layer of binder -a central layer -a layer of binder -an intermediate layer -a layer of binder -an outer layer.

[0109] The binder layers can allow adhesion between adjacent layers. The central layer can accommodate an information-carrying object: a chip, an antenna, or something similar. The intermediate layers can be inked and / or etched. The outer layers can also be inked and / or etched; they can also serve as protective layers for the structure.

[0110] The outer layers

[0111] The outer layer consists of a composition comprising a polyamide matrix.

[0112] For the purposes of this invention, the term "matrix" means that the polyamide is the major component of the composition, i.e., the polyamide present in the highest concentration in the composition. The polyamide matrix may represent from 40% to 100% by weight of the total composition, preferably from 70% to 90% by weight.

[0113] The external composition exhibits a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011.

[0114] It is obtained by polycondensation of at least one motif chosen from an alpha,omega-aminocarboxylic acid in C6 to C18, a lactam in C5 to C12 and a unit (diamine in Ca).(diacid in Cb), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0115] The polyamide can be obtained by polycondensation of at least one lactam selected from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam, pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0116] The polyamide present in the composition of the outer layer can also be obtained by polycondensation of at least one amino acid chosen from 9-aminononanoic acid, 10-aminodecanoic acid (denoted 10), 11-aminoundecanoic acid (denoted 11), 12-aminododecanoic acid (denoted 12).

[0117] Polyamide can be obtained by polycondensation of at least one motif corresponding to the formula (diamine in Ca).(diacid in Cb), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b being between 4 and 36.

[0118] The motif (Ca diamine) may be aliphatic, cycloaliphatic, or aromatic. The diamine may be selected from butanediamine (a=4), pentanediamine (a=5), hexanediamine (a=6), heptanediamine (a=7), octanediamine (a=8), nonanediamine (a=9), decanediamine (a=10), undecanediamine (a=11), dodecanediamine (a=12), tridecanediamine (a=13), tetradecanediamine (a=14), hexadecanediamine (a=16), octadecanediamine (a=18), m-xylylenediamine (denoted MXD), methylpentamethylenediamine (denoted MPMD), the bis(aminomethyl)cyclohexane (noted as BAC), meta-xylylene diamine (MXD, CAS No.: 1477-55-0) and para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0119] Advantageously, diamine X is selected from 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0120] Most preferably, diamine X is in C12 C10, in particular selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0121] The motif (Cb diacid) may be aliphatic, cycloaliphatic or aromatic. The diacid may be selected from succinic acid (b=4), pentanedioic acid (b=5), adipic acid (b=6), heptanedioic acid (b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid (b=10), undecanedioic acid (b=11), dodecanedioic acid (b=12), brassylic acid (b=13), tetradecanedioic acid (b=14), hexadecanedioic acid (b=16), octadecanedioic acid (b=18) and diacids obtained from fatty acids, and terephthalic acid (denoted T).

[0122] Advantageously, the diacid is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0123] Advantageously, the polyamide present in the composition of the outer layer is chosen from PAU, PA12, PA1010, PA 1012, PA 510, PA 513, PA 516, PA 512, PA 610, PA 612, PA613, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 and their mixture.

[0124] According to a preferred embodiment, the polyamide present in the composition of the outer layer is a homopolyamide. This homopolyamide can be obtained by the polycondensation of a lactam, an amino acid, or a (Ca diamine) (Cb diacid) motif, with Ca and Cb being as defined above.

[0125] More particularly, the composition comprises predominantly PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA12, preferably PA11 and mixtures thereof.

[0126] PA11 has the advantage of being manufactured from plant-based raw materials. Plant materials can be cultivated in large quantities, according to demand, across most of the globe and are bio-based. A bio-based raw material is a natural resource, animal or plant-based, whose stock can be replenished over a short period on a human timescale. In particular, this stock must be able to renew itself as quickly as it is consumed.

[0127] The basic raw material of PA11 is castor oil, extracted from the castor bean plant (the common castor bean), from the castor seeds. PA11 is obtained by polycondensation of amino-11-undecanoic acid.

[0128] Preferably, the composition comprises between 70 and 99.5% by weight of at least one polyamide relative to the total weight of the composition, preferably between 85% and 99.5%.

[0129] Additives

[0130] The composition constituting the outer layer may comprise one or more additives selected from antioxidants, UV protectants, UV stabilizers, thermal stabilizers, lubricants, flow improvers, flowability improvers, film-forming agents, film-forming aids, gums, preservatives, antibacterial agents, and mixtures thereof. Preferably, the composition comprises at least one thermal stabilizer.

[0131] The composition constituting the outer layer may comprise from 0.5 to 5% by weight of additives relative to the total weight of the composition. According to a preferred embodiment of the invention, the outer layer consists of a polyamide matrix and 0.5 to 5% by weight of additives relative to the total weight of the composition.

[0132] The structure according to the invention comprises two external layers. These may be identical or different.

[0133] The outer layers preferably have a thickness between 20 and 150 pm, advantageously between 40 and 100 pm, more particularly between 50 and 80 pm.

[0134] The outer layers can be inked and / or engraved.

[0135] The intermediate layers

[0136] The intermediate layer may consist of a composition such as described for the central layer described above.

[0137] The structure according to the invention comprises at least two intermediate layers. These may be identical or different.

[0138] The intermediate layers preferably have a thickness between 100 and 450 pm, advantageously between 150 and 350 pm.

[0139] Preferably, at least one intermediate layer is inked. Advantageously, both intermediate layers are inked.

[0140] The binder layer

[0141] The binder layer consists of a composition that may include a reactive functional polyolefin, that is, a polyolefin that will react with the reactive ends of the polyamide in the adjacent layers to form covalent bonds. The binder layer is non-crosslinked.

[0142] The structure according to the invention may comprise at least four layers of binder. These may be identical or different.

[0143] The binder layers preferably have a thickness between 2 and 40 pm, advantageously between 5 and 30 pm.

[0144] Preferably, the structure according to the invention has a thickness between 500 pm and 1200 pm, advantageously between 700 pm and 900 pm.

[0145] The film manufacturing process

[0146] The invention also relates to a method for preparing a film of composition as defined above by extrusion cast, comprising the following successive steps: -an extrusion step through a flat die of the composition as defined above in the molten state, -a step of drawing the molten material through the air, -a cooling stage on a single thermostatically controlled roller.

[0147] Polymer film extrusion can be carried out by melting polymer granules through a heated Archimedes screw. The transformation temperature must be strictly higher than the melting temperature of the polymer. This extrudate (molten polymer) then passes through a flat die and is drawn in air and then cooled by contact with a thermostatically controlled roller (the so-called cast process).

[0148] Preferably, the process for manufacturing films from the composition according to the invention does not involve a calendering step. It has been observed that the compositions according to the invention make it possible to achieve thinner film thicknesses, in particular the thicknesses required for card manufacturing, without the need for a calendering step. The absence of calendering rollers at the extruder outlet allows for an increase in the speed of the production line, thus leading to a higher manufacturing yield.

[0149] According to a preferred embodiment of the invention, the process for preparing a film of composition as defined above by extrusion cast, comprising the following successive steps:

[0150] -an extrusion step through a flat die of the composition as defined above in the molten state,

[0151] - a step of drawing the molten material in air,

[0152] -a cooling step on a thermostatically controlled roller,

[0153] the composition according to the invention comprising a reinforcing filler, the largest dimension of which is less than 100 pm, preferably less than 50 pm.

[0154] The manufacturing process of the structure

[0155] The invention also relates to the method of manufacturing the structure according to the invention. The method according to the invention comprises the following successive steps: 1. at least one extrusion step of each of the structural components in film form, 2. at least one step of stacking the films on top of each other, 3. at least one compression step, 4. at least one cooling step of the structure, possibly under pressure.

[0156] The process includes a first step of extruding each of the compositions in film form. Each layer can be extruded independently. It is also possible to co-extrude at least two layers together.

[0157] Polymer film extrusion can be carried out by melting polymer granules through a heated Archimedes screw. The transformation temperature must be strictly higher than the polymer's melting temperature. This extrudate (molten polymer) then passes through a flat die and is drawn out in air and then cooled by contact with a thermostatically controlled roller (the so-called cast process). According to one embodiment of the invention, it is possible to co-extrude a two-layer structure comprising a polyamide layer and a binder layer.

[0158] According to another embodiment of the invention, it is possible to co-extrude a three-layer structure comprising a binder layer, a layer comprising polyamide and a binder layer.

[0159] For the purposes of this invention, film means layers with a thickness between 100 and 450 pm, preferably between 150 and 350 pm.

[0160] The so-called binder layers can have a thickness of between 2 and 50 pm, preferably between 4 and 30 pm.

[0161] By stacking in the sense of the present invention, we mean an assembly of films, by superimposing them one on top of the other.

[0162] As indicated above, each layer has a specific thickness depending on its function within the structure.

[0163] The films are then assembled one on top of the other. In other words, they are stacked on top of each other.

[0164] The films thus assembled are compressed.

[0165] The compression step consists of applying pressure, preferably hot, to the structure so as to cause the melting of the binder layers, if present, without causing the melting of the other layers. The melting of the binder allows the films to adhere to each other. The temperature during compression must be higher than the melting or glass transition temperature of the binder layer and lower than the melting temperature of the other layers.

[0166] The process according to the invention has the advantage of linking the different films together during the compression stage of the structure and of achieving the final thickness of the desired structure.

[0167] The temperature during the compression step is preferably between 100 and 140°C, more preferably between 120 and 135°C.

[0168] The duration of the compression step is preferably between 2 and 30 minutes, preferably between 10 and 20 minutes. The duration must be sufficient to allow the layers to adhere to each other.

[0169] The pressure applied during the compression step is preferably between 1 and 50 bars, preferably between 5 and 30 bars.

[0170] According to one embodiment, the process according to the invention comprises a single compression step.

[0171] According to another embodiment, the process according to the invention comprises - a first step of assembling the central layer and the intermediate layers, - a first compression step enabling adhesion of the central and intermediate layers, - a second stage of assembling the structure thus formed with the external layers, and - a second compression stage allowing the structure thus formed to adhere to the external layers.

[0172] The compressed structure is then cooled. It is possible to maintain the pressure during cooling. The pressure can be that of the compression stage or a lower pressure.

[0173] Depending on the desired size of the final object, the resulting structure can be cut. In other words, the manufacturing process for the structure according to the invention can utilize large films, such as films 0.5 m wide by 1 m long, the size of the press often being the limiting factor in these industrial processes. Once this large structure is compressed, a cutting step allows it to achieve the desired shape and therefore the final size.

[0174] The method according to the invention may include additional steps.

[0175] These structures are preferably cards, such as bank cards, identity cards, cards enabling any kind of identification, cards having key functions, in other words cards containing data, whether visibly by inking or engraving or invisibly, via an electronic chip, an antenna, a magnetic stripe or any other device.

[0176] Thus, the method according to the invention may include one or more additional steps to provide the structure with this information or objects.

[0177] Additional inking step

[0178] It is possible to ink at least one external surface of at least one layer of the structure, such as the central layer, the intermediate layers or the external layers.

[0179] Indeed, it is known that identity cards, for example, contain inscriptions made with very specific inks allowing the authenticity of the card to be attested.

[0180] Preferably, the method according to the invention includes an inking step on the outer face of the intermediate layer. Since the structure comprises two intermediate layers, this step can be performed twice, that is, on each of the intermediate layers of the structure. More particularly, this step is performed before the film assembly step.

[0181] When the intermediate layer is inked, the outer layer has a role of protecting these inscriptions arranged on the outer face of the intermediate layer.

[0182] The process according to the invention may also include an inking step of one or both of the external surfaces of the structure after the compression step, and / or optionally after the cooling step.

[0183] Additional engraving step

[0184] The process according to the invention may also include a step of engraving one or both of the external surfaces of the structure, after the compression step, and / or optionally after the cooling step.

[0185] Additional step of cutting the middle layer

[0186] When the structure according to the invention accommodates an object, such as an antenna, an electronic chip, a metallic device, or any other device, the method may include a step of cutting the central layer, followed by a step of depositing the object into the cavity formed during the film assembly step. According to this embodiment, the intermediate layers form the cavity in which the object is placed.

[0187] Therefore, the process according to the invention may include one or more film assembly steps depending on the specificity and treatment of each: inking and / or engraving.

[0188] Use

[0189] The invention finally relates to the use of the structure as defined above as a card containing information, such as a card to secure an electronic identity, a bank card, an identity card, a smart card, a card to control access to a space, such as a building, a room, an entrance vestibule, an elevator, a room, such as a storage space like a wardrobe, a drawer, a safe, a card to control networks and computers.

[0190] The invention will be explained in more detail in the examples that follow. EXAMPLES Example 1 1. Preparation of compositions

[0191] Comparative compositions 1 to 5 were prepared from the compounds listed in Table 1 below. Compositions according to the invention 6 to 11 were prepared from the compounds listed in Table 2 below.

[0192] These compositions were prepared by extrusion on a ZSK26 twin-screw co-rotating extruder (screw diameter 26 mm). The throughput was 30 kg / h at a screw speed of 300 rpm. The extruder temperature was regulated at 260°C. All components are introduced into the main hopper located on the first barrel of the extruder.

[0193] [Tab 1] 1 2 3 4 5 PAU A(1) 95 89 - - - PAU B(2) - - 89 - 91 PAU C(3) - - - 89 - Glass Fibers A( 4 ) - 10 10 10 - Glass Fibers B( 5 ) 4 - - - - Glass Fibers C( 6 ) - - - - 8 Stabilizer 7 ' 1 1 1 1 1 Tf (°C) 189 189 189 189 189 MYoung (GPa) 1.4 1.9 1.9 1.9 2.3 MFI 3.5 1.8 7.5 1.5 7.5

[0194] Table 1

[0195] (1) PA11 A is a PA 11 BESHVO, whose inherent viscosity is 1.45.

[0196] (2)PA11 B is a PA 11 KNO, whose inherent viscosity is 1.4.

[0197] (3) PA11 It is a PA 11 BESNO 600.

[0198] ( 4 'Glass fibers A are marketed under the trade name Lanxess MF7982 sold by Lanxess, medium size 150 pm. The form factor is 10.7.

[0199] (5 'B glass fibers are marketed under the trade name Lanxess MF7904 sold by Lanxess, medium size 50 pm. The form factor is 3.6.

[0200] (6 'C glass fibers are marketed under the trade name Lanxess CS MF7928 fibers, sold by Lanxess, are 4.5 mm in size. These fibers are then milled to obtain an average size of 400 µm. The form factor is 36.

[0201] (7 'The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarol EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0202] [Tab 2] 6 7 8 9 10 11 PAU A(1) 79 - 59 84 59 - PA MXD10(2) - - 25 - 25 - PAU B(3) - - - - - 84 PAU C(4) - 79 - - - - Glass fibers b(5) 20 20 - - - - Talc( 6 ' - - 15 - - - Talc( 7 ' - - - 15 15 15 Stabilizer 8 ' 1 1 1 1 1 1 Tf (°C) 189 189 189 189 189 189 MYoung (GPa) 1.9 1.9 3 2.5 3.1 2.5 MFI 1.8 6 1.4 0.9 1.4 7.5

[0203] Table 2

[0204] (1)PA11 A is a BESHVO, whose inherent viscosity is 1.45.

[0205] ( 2 'PA MXD10 is an XMFO polyamide sold by ARKEMA.

[0206] ( 3 'PAl 1 B is a PA 11 KNO, whose inherent viscosity is 1.4.

[0207] (4 'PA 11 C is a PA 11 BESNO 600.

[0208] (5 'B glass fibers are marketed under the trade name Lanxess MF7904 sold by Lanxess, medium size 50 pm. The form factor is 3.6.

[0209] (6 'Talc is marketed under the trade name Jetfine 3CA sold by Imerys. The form factor is 3.4.

[0210] (7 'Talc is marketed under the trade name HAR W92 sold by Imerys. The form factor is 4.8.

[0211] (8 'The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarol EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0212] The properties of the compositions are measured according to the following protocols:

[0213] Measurement of 1 at melting temperature Enthalpy of fusion was measured by DSC using a TA Instruments Q2000DSC instrument according to ISO 11357. Thermograms were processed using TA Universal Analysis software. DSCs were performed under nitrogen with a 6-8 mg sample. The following program was followed for all measurements presented in this report: Equilibrium at -40°C Initial heating from -40°C to 270°C at 20°C / min Cooling from 270°C to -40°C at 20°C / min Second heating from -40°C to 270°C at 20°C / min In order to disregard the thermal history of the material, the value at the second heating is recorded. Measurement of Young's modulus

[0214] The modulus of the composition is measured according to ISO 527-1A 2019 on an injection-molded test specimen according to the following measurement protocol:

[0215] Dynamometer: Instron

[0216] Test pieces: ISO 527-1A

[0217] Test speed: 1 mm / min (modulus), then 50 mm / min (cont. and ail. to break)

[0218] Jaw: Pneumatic

[0219] Distance between jaws: 115 mm

[0220] Extensometer: mechanical (L0=75mm)

[0221] Force cell: 10 kN

[0222] Temperature: 23°C

[0223] Storage: 15 days at 23°C at 50% relative humidity.

[0224] MFI Measurement The MFI of these diapers is measured according to ASTM 1238-2020 at 235°C and 2.16 kg-

[0225] Film 1 is to be discarded, as it is too flexible. Its Young's modulus, evaluated in Table 1, is too low: 1.4 GPa. 2. Film preparation

[0226] Polymer films are produced by extrusion cast.

[0227] Cast extrusion is the extrusion of molten polymer by a single screw exiting through a flat die, followed by cooling through successive rollers. The films are stretched by the acceleration of the thermostatically controlled roller; this acceleration of the molten polymer allows the desired thickness and width to be obtained.

[0228] Extrusion is carried out on a COLLIN brand line, with a 45 mm diameter extruder with a length equal to 25 times the diameter. The extrusion temperatures are set to obtain a material temperature of 230 to 240°C.

[0229] The thickness of the films is 150 pm. 3.Evaluation of the processability of films

[0230] The following properties are evaluated as follows:

[0231] Possibility of carrying out an extrusion step via a cast process

[0232] The possibility of carrying out an extrusion step via a cast process from the tested compositions is evaluated.

[0233] O means yes: The films obtained are satisfactory in terms of thickness homogeneity.

[0234] N means no: The films have holes and / or roughness. They tear during the stretching stage.

[0235] Dimensional quality and structural connection / surface appearance.

[0236] The surface appearance of films obtained during cast extrusion is defined visually. Surface roughness defects in the film are observable to the naked eye by a person skilled in the art.

[0237] [Tab 3] 2 3 4 5 Cast extrusion NNNN Surface appearance rough rough rough rough

[0238] Table 3

[0239] [Tab 4] 6 7 8 9 10 11 Cast extrusion OOOOOO Smooth surface appearance smooth smooth smooth smooth smooth

[0240] Table 4 4. Conclusion

[0241] The specific choice of materials makes it possible to obtain a molten material extrudable via a casting process, which allows for the production of films without surface defects. Example 2 1. Preparation of compositions

[0242] The following compositions were prepared for the purpose of manufacturing the structures described below.

[0243] 1.1. Composition of the outer layers

[0244] The compositions were prepared from the compounds listed in Table 5 below.

[0245] These compositions were prepared by extrusion on a ZSK26 twin-screw co-rotating extruder (screw diameter 26 mm). The throughput was 30 kg / h at a screw speed of 300 rpm. The extruder temperature was regulated at 260°C. All components are introduced into the main hopper located on the first barrel of the extruder.

[0246] [Tab 5] 12 13 PAU B(1) - 52.3 PAU A(2) 99 34.1 Platamid( 3 ' - 12 Stabilizer( 4 ' 1 1.6 Tf (°C) 189 189 Transmittance (%) 80 80 MFI 1 1

[0247] Table 5

[0248] (1)PA11 B is a PA 11 KNO whose inherent viscosity is 1.4.

[0249] ®PA11 A is a PA 11 BESHVO with an inherent viscosity of 1.45.

[0250] ( 3 ' Platamid is a Platamid reference HX2507 sold by ARKEMA.

[0251] ( 4 'The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarol EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0252] The properties of the compositions are measured according to the following protocols:

[0253] Measurement of 1 at melting temperature Enthalpy of fusion was measured by DSC using a TA Instruments Q2000DSC instrument according to ISO 11357. Thermograms were processed using TA Universal Analysis software. DSCs were performed under nitrogen with a 6-8 mg sample. The following program was followed for all measurements presented in this report: Equilibrium at -40°C Initial heating from -40°C to 270°C at 20°C / min Cooling from 270°C to -40°C at 20°C / min Second heating from -40°C to 270°C at 20°C / min In order to disregard the thermal history of the material, the value at the second heating is recorded.

[0254] Measurement of 1 a transmittance Transmittance is measured according to the ASTDM D1003-2011 standard, on 0.6 mm thick samples by UV-Vis spectrometry on the Cary 300 spectrometer under the following conditions:

[0255] - Accessory: Integration sphere (transmission including diffusion)

[0256] - Spectral range 800-200 nm

[0257] - Speed: 60 nm / min

[0258] - 1 nm bandwidth

[0259] - Scale: Transmittance

[0260] MFI Measurement The MFI of these diapers is measured according to ASTM 1238-2020 at 235°C and 2.16 kg- 1. Composition of the intermediate and central layers

[0261] The compositions were prepared from the compounds listed in Table 6 below. These compositions were prepared by extrusion on a ZSK26 co-rotating twin-screw extruder (screw diameter 26 mm). The throughput was 30 kg / h at a screw speed of 300 rpm. The extruder temperature was regulated at 250°C.

[0262] The polyamides and the stabilizer are introduced into the main hopper located on the first barrel of the extruder. The glass fiber and talc are introduced via a lateral feeder to barrel 5.

[0263] [Tab 6] 9 10 14 PA11A(1) 84 59 65 PA MXD10(2) - 25 25 Talc( 3 ' 15 15 9 Stabilizer( 4 ' 1 1 1 Tf (°C) 189 189 189 MYoung (GPa) 2.4 3.1 2.5 MFI 1.1 1.8 1.9

[0264] Table 6

[0265] ( 1 ' PA11 A is a PA 11 BESHVO, whose inherent viscosity is 1.45.

[0266] ( 2 ' PA MXD10 is an XMFO polyamide sold by ARKEMA.

[0267] (3 'Talc is marketed under the trade name HAR W92 sold by Imerys. The form factor is 4.8.

[0268] ( 4 'The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarol EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0269] The measurements of the melting temperature, Young's modulus, and MFI of these intermediate and outer central layers are measured according to the methods described above in point 1.1.

[0270] 1.2.Binder layer compositions

[0271] The binder compositions used in the structures below are commercial products.

[0272] Orevac 18342 N is a maleic anhydride-grafted high-density polyethylene (HDPE) sold by SK Functional Polymer. It has a MFI of 3.5 g / l min and a melting point of 125 °C. The product is designated by O in Table 2 below.

[0273] Lotader 4513T is a terpolymer of ethylene, methyl acrylate, and maleic anhydride sold by SK Functional Polymer. It has a melting point of 8 g / L and a melting point of 96 °C. The product is designated by L in Table 2 below.

[0274] MFI Measurement MFI is measured according to ASTM 1238-2020 at 190°C, 2.16 kg for binder layers.

[0275] The melting temperature of the binder layer is measured according to the method described above in section 1.1. Generally, the values ​​of MFI and Tf These values ​​are provided by the manufacturers. They are available in the TDS (Total Data Sheets) of the products. 2. Preparation of the structures

[0276] The structures are prepared according to the following protocol: 1. The layers are extruded as a film. The extruded layers are produced using a Collin brand cast extrusion line. The line consists of three extruders with diameters of 25, 30, and 45 mm. The processing temperature is set at 240°C for all polymers. 2. The films are stacked on top of each other. 3. The stacked films are compressed at 135°C for a period of 20 minutes under a pressure of 15 bars. 4. The consolidated structure is then cooled to a temperature of 23 °C for 20 minutes at a pressure of 15 bar.

[0277] The consolidated structures are then removed from the press and are ready for use.

[0278] The structures have a thickness of 840 pm before compression, and 800 pm After compression, the intermediate and inner layers are each 220 µm thick. The outer layers are each 60 µm thick. The binder layers are each 15 µm thick.

[0279] The following structures described in Table 7 were prepared from the compositions described in Tables 5 and 6 above and from the binders described above:

[0280] [Tab 7] CExt Binder CInterm Binder CCentral Binder CInterm Binder CExt Compl 12 - 12 - 12 - 12 - 12 Comp2 13 O 12 O 12 O 12 O 13 Invl 13 O 9 O 9 O 9 O 13 Inv2 13 O 10 O 10 O 10 O 13 Inv3 12 L 10 L 10 L 10 L 12 Inv4 12 L 9 L 9 L 9 L 12 Inv5 12 L 9 L 14 L 9 L 12

[0281] Table 7 3. Evaluation of structures

[0282] The following physicochemical properties are evaluated on the structures described in Table 7:

[0283] Measurement of adhesive performance The adhesion between the layers is measured according to the ISO 10373-1-2020 standard.

[0284] Adhesion is measured on the Outer Layer / Binder / Intermediate Layer films and on the Middle Layer / Binder / Intermediate Layer films. The lower of these two measurements is retained.

[0285] An adhesion greater than 5 N / cm is acceptable for this application.

[0286] Measurement of the traction modulus The tensile modulus is measured according to ISO 178:2019 on a sample cut from the structure and then conditioned for 15 days at 23°C and 50% relative humidity. The tensile strength measurement is performed on test specimens conforming to ISO 5271-A:2019.

[0287] A tensile modulus for the structure greater than 1 GPa is acceptable for this application. 4. Results

[0288] The results of the properties evaluated on the structures are shown in Table 8 below:

[0289] [Tab 8] Adhesion Tensile Modulus (N / cm) (GPa) Compl 0 <1 Comp2 6 <1 Invl 32 >1 Inv2 30 >1 Inv3 15 >1 Inv4 15 >1 Inv5 15 >1

[0290] Table 8

[0291] Table 9 below shows the composition of the structure once melted for recycling. The composition includes all the components of all the layers of the structure. The component contents of this composition are calculated by taking into account the component contents in each layer and the thickness of each layer. The thickness factor of each layer is converted into a percentage relative to the total thickness of the structure.

[0292] [Tab 9] Inv1 75.6% polyamide, 10.3% polyolefin, 1.6% platinum, 11.4% filler, and 1% additives Inv2 75.6% polyamide, 10.3% polyolefin, 1.7% platinum, 11.4% filler, and 1% additives Inv3 77.3% polyamide, 10.3% polyolefin, 11.4% filler, and 1% additives Inv4 77.3% polyamide, 10.3% polyolefin, 11.4% filler, and 1% additives Inv5 81.8% polyamide, 10.3% polyolefin, 6.8% filler, and 1% additive

[0293] Table 9 4. Conclusions

[0294] The results show that the structures according to the invention are satisfactory in terms of interlayer adhesion and rigidity. Moreover, their chemical compositions make them fully recyclable.

Claims

Demands

1. Composition comprising: -a polyamide matrix predominantly comprising at least one polyamide having a C / N ratio greater than or equal to 8 and -from 5 to 20% by weight of a reinforcing filler having a shape factor between 2 and 9.

2. Composition according to claim 1, characterized in that it has a Young's modulus measured according to ISO 527-1A 2019 of between 1.8 and 4 GPa, preferably between 2 and 3.5 GPa.

3. Composition according to claim 1 or 2, characterized in that it has an MFI measured according to ASTM 1238-2020 at 235°C and 2.16 kg of between 0.4 and 15 g / 10min, preferably 0.4 and 10 g / 10min.

4. Composition according to any one of the preceding claims, characterized in that the polyamide matrix comprises at least one polyamide selected from PAU, PA 12, PA 1010, PA 1012, PA 513, PA 516, PA 612, PA613, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014, MXD10, MXD12, MXD13, PA10 / 11T, and mixtures thereof.

5. Composition according to any one of the preceding claims, characterized in that the polyamide matrix comprises at least one polyamide selected from PAU, PA 12, PA 1010 and PA 1012.

6. Composition according to any one of the preceding claims, characterized in that the reinforcing filler is selected from calcium carbonate, silicas, quartz, diatomaceous earth, wollastonites, aluminosilicates, such as kaolin, magnesia, slag, slate flour, vermiculite, mica, fibers, preferably ground, preferably ground glass fibers, aramid fibers, glass flakes, glass beads, talc, carbonaceous fillers, such as graphite, expanded graphite, carbon black, nanofillers, metal oxides, such as titanium oxide, most preferably talc and ground fibers.

7. Composition according to any one of the preceding claims, characterized in that the largest dimension of the charge is less than 100 pm, preferably less than 50 pm.

8. Composition according to any one of the preceding claims, characterized in that the filler is talc.

9. Composition according to any one of the preceding claims, characterized in that the composition comprises at least one reinforcing filler in a content of 7 to 17% by weight relative to the total weight of the composition.

10. Composition according to any one of the preceding claims, characterized in that it is in the form of a film of thickness between 100 and 450 pm.

11. Multilayer structure comprising at least one layer made of a composition as defined in any one of claims 1 to 10.

12. Structure according to claim 11, characterized in that the layer constitutes the central layer and / or at least one intermediate layer of the structure.

13. Structure according to claim 11 or 12, characterized in that it comprises at least one outer layer made of a composition comprising a polyamide matrix, the outer composition having a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011.

14. A structure according to any one of claims 11 to 13, characterized in that it comprises: - an outer layer made of a composition comprising a polyamide matrix, the outer composition having a transmittance greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011, - an intermediate layer made of a composition as described in any one of claims 1 to 10, - a central layer made of a composition as described in any one of claims 1 to 10, - an intermediate layer made of a composition as described in any one of claims 1 to 10, -an outer layer consisting of a composition comprising a polyamide matrix, the outer composition having a transmittance rate greater than or equal to 70% in the visible range (400 to 800 nm) on films 600 pm thick, measured according to ASTM-D1003-2011, the compositions constituting the outer layers, the intermediate layers and the central layer having a melting temperature greater than 150°C, preferably greater than 160°C.

15. A method for preparing a film of composition as defined in claim 10, comprising the following successive steps: - an extrusion step through a flat die of the composition as defined in any one of claims 1 to 9 in the molten state, - an air-drawing step of the molten material, - a cooling step on a thermostatically controlled roller.

16. A method for manufacturing the structure as defined in any one of claims 11 to 14, comprising the following successive steps:

1. at least one extrusion step of each of the compositions of the structure in the form of films, 2. at least one step of stacking the films one on top of the other, 3. at least one compression step, 4. at least one cooling step of the structure, optionally under pressure.

17. Use of the structure as defined in any one of claims 11 to 14 as a card containing data, such as a card to secure an electronic identity, a bank card, an identity card, a smart card, a card to control access to a space, such as a building, a room, an entry vestibule, an elevator, a premises, such as a storage space like a cabinet, a drawer, a safe, a card to control networks and computers.