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

Abstract

The present invention relates to a 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 wt% of a reinforcing filler having a form factor of between 2 and 9. The invention also relates to a method for preparing a film from this composition. The invention also relates to a structure which can be used as a card comprising data, such as a card for securing an electronic identity, a bank card, an identity card, a smart card, a card for controlling access to a space, such as a building, a room, an entrance airlock, an elevator, or an area, such as a storage space like a cupboard, a drawer, or a safe, and a card for controlling networks and computers.

Description

[0001] Composition for a multilayer structure based on polyamide usable as a card

[0002] technical field

[0003] The present invention relates to a composition for a multilayer structure usable as a card, as well as its manufacturing process.

[0004] Technical background

[0005] Smart cards, also known as chip cards, provide a secure framework for 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 stored through ink or engraving, or invisibly stored via an electronic chip, antenna, magnetic stripe, or other device.

[0006] 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.

[0007] The use of polyamides to manufacture cards is known from documents US2021 / 0268823 and US2022 / 0363953.

[0008] Technical problem to solve

[0009] However, the materials sought must meet specific requirements. Ideally, they should be able to replace PVC in the card manufacturing process without any modifications to the process itself. This process involves film production followed by heat compression of these films, which allows for adhesion between the layers and shapes the object into a card.

[0010] One of the challenges in choosing the material lies in the difference in rigidity between PVC and polyamides, particularly long-chain polyamides. It is essential to ensure the product's durability over time, low deformation during use, and a certain level of mechanical rigidity in the core layers of the object.

[0011] Next, the films produced must have the same surface appearance and dimensional and structural quality as objects made of PVC.

[0012] The addition of fillers to polyamides is known. However, the ability to manufacture 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 process in a film manufacturing process, particularly an extrusion-cast process.

[0013] The technical problem is therefore to propose a composition enabling the production of polyamide films, in particular long-chain films, resulting in a film with a thickness between 150 and 450 pm, rigid and without defects in cast extrusion.

[0014] Thus, a specific polyamide-based composition was found that allows the manufacture of films meeting criteria of rigidity and recyclability, resulting in parts without surface defects. Brief description of the invention

[0015] The present invention relates to a composition comprising

[0016] -a polyamide matrix comprising predominantly at least one polyamide having a C / N ratio greater than or equal to 8 and

[0017] -from 5 to 20% by weight of a reinforcing load having a form factor between 2 and 9.

[0018] The invention also relates to an extrusion-cast process which implements the composition according to the invention.

[0019] The invention also relates to a multilayer structure comprising at least one layer made of a composition as defined above.

[0020] The invention also relates to a method for preparing a film of composition as defined above, comprising the following successive steps:

[0021] -an extrusion step through a flat die of the composition as defined above in the molten state,

[0022] -a step of drawing the molten material through the air,

[0023] -a cooling stage on a thermostatically controlled roller.

[0024] The invention also relates to the manufacturing process of the structure as defined above, comprising the following successive steps:

[0025] 1. at least one extrusion step of each of the structural components in film form,

[0026] 2. at least one step of stacking the films on top of each other,

[0027] 3. at least one compression step,

[0028] 4. at least one cooling stage of the structure, possibly under pressure.

[0029] The invention also relates to the use of the structure 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 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.

[0030] The structure according to the invention has the advantage of being mechanically recyclable. There is no need to separate the polymers. The resulting mixture can be directly reused either for the same application or for another application.

[0031] Indeed, the composition resulting from the recycling of the structure according to the invention comprises mainly one or more polyamides, and fillers. In fact, 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.

[0032] Furthermore, when the structure consists mainly or exclusively of PA 11 as the matrix for the outer, intermediate, and central layers, the structure is largely bio-based. Its environmental impact is low compared to raw materials of fossil origin.

[0033] Other advantageous characteristics of the composition according to the invention are specified below.

[0034] -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. -The composition has a 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.

[0035] -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.

[0036] -The polyamide matrix comprises at least one polyamide selected from PAU, PA12, PA1010 and PA 1012.

[0037] -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, very preferably talc and ground glass fibers.

[0038] -The largest dimension of the load is less than 100 pm, preferably less than 50 pm.

[0039] -The filler is talc.

[0040] -The composition includes at least one reinforcing filler with a content ranging from 7 to 17% by weight relative to the total weight of the composition.

[0041] The composition is found in the form of a film with a thickness between 100 and 450 µm.

[0042] Other advantageous features of the structure according to the invention are specified below.

[0043] -Said layer constitutes the central layer and / or at least one intermediate layer of the structure.

[0044] -The structure includes 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.

[0045] -The structure includes:

[0046] -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,

[0047] -an intermediate layer consisting of a composition such as described above,

[0048] -a central layer made up of a composition such as described above,

[0049] -an intermediate layer consisting of a composition such as described above,

[0050] -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 µm thick, measured according to ASTM-D1003-2011, the compositions constituting the outer layers, intermediate layers and the core layer having a melting point greater than 150°C, preferably greater than 160°C. Detailed description

[0051] Other features, aspects, objects and advantages of the present invention will become even clearer upon reading the description that follows.

[0052] Unless otherwise stated, all percentages are mass percentages.

[0053] 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.

[0054] It is specified that the expressions "from ... to ..." and "between ... and ..." used in this description should be understood as including each of the mentioned limits.

[0055] The form factor corresponds to a dimensionless variable allowing comparison of the various loads with each other.

[0056] Polyamides

[0057] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", specifically on page 3 (Tables 1 and 2), and is well known to those skilled in the art. Thus, PAU signifies that it is obtained by polycondensation of amino-11-undecanoic 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).

[0058] The word "polyamide" covers both homopolyamides and copolyamides.

[0059] The invention is now described in more detail and in a non-limiting manner in the following description.

[0060] Polyamides are obtained by a polycondensation reaction of monomers, which can be amino acids or lactams, denoted Z, or chains of diacids and diamines, denoted XY, where X represents a diamine and Y a diacid. Thus, an amide group is formed by the reaction of an amine group with an acid group.

[0061] For the purposes of this invention, a unit is understood to be a Z or XY link resulting from the polycondensation of monomers.

[0062] For the purposes of this invention, the term "motif" means the sequence Z, the sequence X, or the sequence Y. In other words, unit Z consists of a motif Z, and unit XY consists of a motif X and a motif Y.

[0063] For the purposes of this invention, the C / N ratio means the average number of carbon atoms per nitrogen atom per unit.

[0064] In the case of a PA Z homopolyamide, where Z designates a repeating unit obtained from an amino acid or a lactam, the number of carbon atoms per nitrogen atom is the number of carbon atoms in the repeating unit. For example, PA 11 obtained by polycondensation of amino-11-undecanoic acid has a C / N ratio of 11.

[0065] In the case of a PA XY homopolyamide, where X represents a unit obtained from a diamine and Y represents a unit obtained from a diacid, the number of carbon atoms per nitrogen atom is the average 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 (6+12) / 2 = 9.

[0066] 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 the molar proportion of the different amide units, that is to say, the XaYa and XbYb units. Thus, the coPA 10T / 106 containing 60% 10T and 40% 106 is in C8.6: 60%x[(10+8) / 2]+40%x[(10+6) / 2] = 8.6.

[0067] The composition

[0068] The composition includes:

[0069] -a polyamide matrix comprising predominantly at least one polyamide having a C / N ratio greater than or equal to 8 and

[0070] -from 5 to 20% by weight of a reinforcing load having a form factor between 2 and 9.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The polyamide present in the matrix of the central and / or intermediate layer composition 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.

[0075] Polyamide can be obtained by polycondensation of at least one lactam selected from pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0076] 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 (noted 10), 11-aminoundecanoic acid (noted 11), 12-aminododecanoic acid (noted 12).

[0077] 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.

[0078] The motif (diamine in Ca) can be aliphatic, cycloaliphatic or aromatic. The diamine can be chosen 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-xylylene diamine (MXD), methylpentamethylene diamine (MPMD), bis(aminomethyl)cyclohexane (BAC), meta-xylylene diamine (MXD, CAS No. 1477-55-0), and the para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0079] Advantageously, diamine X is chosen from among 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0080] Preferably diamine X is in C12 C10, in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0081] The motif (Cb diacid) can be aliphatic, cycloaliphatic or aromatic. The diacid can 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).

[0082] 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.

[0083] 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.

[0084] 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.

[0085] According to a preferred embodiment, the polyamide in the matrix of the core and / or intermediate layer composition is a homopolyamide. This homopolyamide can be obtained by the polycondensation of a lactam, an amino acid, or a diamine (Ca) or diacid (Cb) motif, with Ca and Cb being as defined above. Advantageously, the polyamide in the matrix of the composition has a glass transition temperature (Tg) greater than 40°C, preferably greater than 50°C, and more preferably greater than 60°C, measured by DSC according to ISO 11357-2:2013, measured on a dry material, i.e., containing less than 0.1% moisture, measured according to ISO 11357-1:2009.

[0086] Advantageously, the polyamide present in the matrix of the composition of the central and / or intermediate layer has a C / N ratio between 10 and 16, preferably between 9 and 14, more preferably between 10 and 12.

[0087] More specifically, the composition matrix mainly comprises PAU, PA12, PA1010, PA 1012, even more preferentially PAU or PA12, preferably PAU.

[0088] Preferably, the composition matrix 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%.

[0089] Fillers The composition according to the invention comprises one or more reinforcing fillers having a form factor between 2 and 9, preferably between 2.5 and 7.

[0090] 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.

[0091] For the purposes of this invention, "reinforcing filler" means a filler which, when present in a content of 10% by weight in a polyamide matrix, relative to the total weight of the assembly {matrix + filler}, increases the Young's modulus (GPa) of this assembly by a factor of at least 30%, preferably at least 50%, measured according to ISO 527-1A 2019, relative to the Young's modulus of the polyamide matrix without filler.

[0092] 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 glass fibers.

[0093] 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.

[0094] 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.

[0095] 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 of laser d50 to Sedigraph d50.

[0096] 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.

[0097] For 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.

[0098] The "tapped bulk" density, as defined by ISO 787 / 11 for talcs, is between 0.7 and 1 g / cm³ 3 .

[0099] According to a preferred embodiment, the reinforcing filler is talc. The talc may be present in a content of 5 to 20% by weight, preferably 7 to 17% by weight, more preferably 8 to 15% by weight, relative to the total weight of the composition. According to a second preferred embodiment, the reinforcing filler is a fiber, preferably ground fibers, most advantageously ground glass fibers. 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 (#06781G), 2001 ASM International).

[0100] Glass fibers typically have a diameter between 5 and 20 pm, preferably the fiber diameter is between 10 and 18 pm.

[0101] Standard glass fibers are generally several millimeters long and, after compounding and extrusion, have average lengths of over 200 µm. Therefore, the shape factor for these fibers is obtained by the ratio of average length to diameter.

[0102] 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.

[0103] 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.

[0104] For example, the following commercial glass fibers can be used: Lanxess MF 7904 glass fiber with an average length of 50 µm and an average diameter of 14 µm.

[0105] According to a preferred embodiment, the reinforcing filler is ground glass fiber. The ground glass fibers may be present in a content of 5 to 20% by weight, preferably 7 to 17% by weight, more preferably 8 to 15% by weight, relative to the total weight of the composition.

[0106] Preferably, the reinforcing charge has a thermal conductivity between 0 and 4 W / mK, preferably between 0 and 3 W / mK, more preferably between 0 and 1 W / mK, measured according to ASTM D5930-17. In other words, the reinforcing charge is thermally insulating.

[0107] Preferably, the reinforcing load has a surface resistivity greater than 1010 Ω, preferably greater than 1011 Ω measured according to IEC 62631-3-2 (2015). In other words, the reinforcing load is electrically insulating.

[0108] 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.

[0109] 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.

[0110] Additives

[0111] The composition according to the invention 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, pigments, and mixtures thereof. Preferably, the composition comprises at least one thermal stabilizer. The composition may contain from 0.4 to 5% by weight of additives relative to the total weight of the composition.

[0112] Preferably, the composition is in the form of a film with a thickness between 100 and 450 µm, preferably between 150 and 350 µm.

[0113] The central layer and the intermediate layer(s) each preferably have a thickness between 100 and 450 µm, advantageously between 150 and 350 µm. In particular, the thickness of the central layer depends on the object to be accommodated.

[0114] Preferably, the composition has a melting point above 150°C, preferably above 160°C.

[0115] According to a preferred embodiment, the composition comprises a polyamide matrix consisting mainly of a homopolyamide, and on the other hand a reinforcing filler selected from talc and ground glass fibers.

[0116] In a particularly preferred manner, the composition comprises a polyamide matrix consisting mainly of a homopolyamide, and on the other hand a reinforcing filler chosen from talc.

[0117] In an alternative embodiment, the composition comprises a polyamide matrix consisting mainly of a homopolyamide, and on the other hand a reinforcing filler selected from ground glass fibers.

[0118] The multilayer structure

[0119] The multilayer structure according to the invention comprises at least one layer made of a composition as described above.

[0120] 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.

[0121] The structure may include the following layers, according to this arrangement: -an outer layer

[0122] -an intermediate layer

[0123] -a central layer

[0124] -an intermediate layer

[0125] -an outer layer.

[0126] The structure may also include the following layers, according to this arrangement: -an outer layer -a binder layer -an intermediate layer -a binder layer -a central layer -a binder layer

[0127] -an intermediate layer

[0128] -a layer of binder

[0129] -an outer layer. Binder layers allow adhesion between adjacent layers. The central layer can house an information-carrying object: a chip, an antenna, or something else. 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.

[0130] The outer layers

[0131] The outer layer consists of a composition comprising a polyamide matrix.

[0132] For the purposes of this invention, the term "matrix" refers to the polyamide that is the major component of the composition, i.e., the polyamide present in the highest concentration. The polyamide matrix may represent from 40% to 100% by weight of the total composition, preferably from 70% to 90% by weight.

[0133] 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 the ASTM-D1003-2011 standard.

[0134] 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.

[0135] Polyamide can be obtained by polycondensation of at least one lactam selected from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam, pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0136] 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 (noted 10), amino-11-undecanoic acid (noted 11), amino-12-dodecanoic acid (noted 12).

[0137] 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.

[0138] The motif (diamine in Ca) can be aliphatic, cycloaliphatic or aromatic. The diamine can be chosen 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-xylylene diamine (MXD), methylpentamethylene diamine (MPMD), bis(aminomethyl)cyclohexane (BAC), meta-xylylene diamine (MXD, CAS No. 1477-55-0), and the para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0139] 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, and 1,12-dodecamethylenediamine. Most preferably, diamine X is in the C12 C10 configuration, particularly selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, and 1,12-dodecamethylenediamine.

[0140] The motif (Cb diacid) can be aliphatic, cycloaliphatic or aromatic. The diacid can 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).

[0141] 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.

[0142] 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.

[0143] 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 diamine (Ca) or diacid (Cb) motif, with Ca and Cb being as defined above.

[0144] More specifically, the composition mainly comprises PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA12, preferably PAU and their mixture.

[0145] PAU has the advantage of being made from plant-based raw materials. These 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 in a short period on a human timescale. In particular, this stock must be able to renew itself as quickly as it is consumed.

[0146] The basic raw material for PAU is castor oil, extracted from the castor bean plant (the common castor bean plant) using castor seeds. PAU is obtained by polycondensation of amino-11-undecanoic acid.

[0147] 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%.

[0148] Additives

[0149] The composition constituting the outer layer may include 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 includes at least one thermal stabilizer.

[0150] The composition constituting the outer layer may contain 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.

[0151] The structure according to the invention comprises two external layers. These may be identical or different.

[0152] 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.

[0153] The outer layers can be inked and / or engraved.

[0154] The intermediate layers

[0155] The intermediate layer can be made of a composition such as described for the central layer described above.

[0156] The structure according to the invention comprises at least two intermediate layers. These may be identical or different.

[0157] The intermediate layers preferably have a thickness between 100 and 450 pm, advantageously between 150 and 350 pm.

[0158] Preferably, at least one intermediate layer is inked. Advantageously, both intermediate layers are inked.

[0159] The binder layer

[0160] 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 adjacent layers to form covalent bonds. The binder layer is non-crosslinked.

[0161] The structure according to the invention may comprise at least four layers of binder. These may be identical or different.

[0162] The binder layers preferably have a thickness between 2 and 40 pm, advantageously between 5 and 30 pm.

[0163] Preferably, the structure according to the invention has a thickness between 500 pm and 1200 pm, advantageously between 700 pm and 900 pm.

[0164] Preferably, the intermediate layers and the central layer comprise an identical polyamide matrix, advantageously the matrix comprises predominantly a homopolyamide.

[0165] Preferably, the intermediate layers and the central layer have an identical composition.

[0166] The film manufacturing process

[0167] 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 stretching step in air of the molten material,

[0168] -a cooling stage on a single thermostatically controlled roller.

[0169] 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 point. This extrudate (molten polymer) then passes through a flat die and is drawn through air before being cooled by contact with a thermostatically controlled roller (a process known as casting).

[0170] Preferably, the film manufacturing process using 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, particularly 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 increased production line speed, thus leading to higher manufacturing output.

[0171] According to a preferred embodiment of the invention, the process for preparing a film of composition as defined above by extrusion cast comprises the following successive steps:

[0172] -an extrusion step through a flat die of the composition as defined above in the molten state,

[0173] -a step of drawing the molten material through the air,

[0174] -a cooling stage on a thermostatically controlled roller, 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.

[0175] The manufacturing process of the structure

[0176] 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:

[0177] 1. at least one extrusion step of each of the structural components in film form,

[0178] 2. at least one step of stacking the films on top of each other,

[0179] 3. at least one compression step,

[0180] 4. at least one cooling stage of the structure, possibly under pressure.

[0181] The process includes a first step of extruding each of the compositions as a film. Each layer can be extruded independently. It is also possible to co-extrude at least two layers together.

[0182] 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 point. This extrudate (molten polymer) then passes through a flat die and is drawn in air before being cooled by contact with a thermostatically controlled roller (a process known as casting). According to one embodiment of the invention, it is possible to co-extrude a bilayer structure comprising a polyamide layer and a binder layer.

[0183] According to another embodiment of the invention, it is possible to co-extrude a three-layer structure comprising a binder layer, a polyamide layer, and a binder layer. For the purposes of this invention, "film" refers to layers with a thickness between 100 and 450 µm, preferably between 150 and 350 µm.

[0184] The so-called binder layers can have a thickness of between 2 and 50 pm, preferably between 4 and 30 pm.

[0185] Stacking, as used in the present invention, means assembling the films by layering them one on top of the other.

[0186] As mentioned above, each layer has a specific thickness depending on its function within the structure.

[0187] The films are then assembled one on top of the other. In other words, they are stacked on top of each other.

[0188] The films thus assembled are compressed.

[0189] The compression step involves applying pressure, preferably hot, to the structure to melt the binder layers, if present, without melting the other layers. The melting of the binder allows the films to adhere to each other. The temperature during compression must be above the melting or glass transition temperature of the binder layer and below the melting temperature of the other layers.

[0190] The process according to the invention has the advantage of linking the different films together during the compression stage of the structure and achieving the final thickness of the desired structure.

[0191] The temperature during the compression stage is preferably between 100 and 140°C, even more preferably between 120 and 135°C.

[0192] The compression step should preferably last between 2 and 30 minutes, and ideally between 10 and 20 minutes. This duration must be sufficient to allow the layers to adhere to each other.

[0193] The pressure applied during the compression stage is preferably between 1 and 50 bars, preferably between 5 and 30 bars.

[0194] According to one embodiment, the process according to the invention comprises a single compression step.

[0195] According to another embodiment, the method according to the invention comprises

[0196] - a first step of assembling the central layer and the intermediate layers,

[0197] - a first compression stage allowing adhesion of the central and intermediate layers,

[0198] - a second stage of assembling the structure thus formed with the external layers, and

[0199] - a second compression stage allowing the structure thus formed to adhere to the external layers.

[0200] The compressed structure is then cooled. It is possible to maintain the pressure during cooling. The pressure can be the same as that of the compression stage or a lower pressure.

[0201] 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, with 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.

[0202] The method according to the invention may include additional steps.

[0203] These structures are preferably cards, such as bank cards, identity cards, cards allowing any kind of identification, cards with 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.

[0204] Thus, the process according to the invention may include one or more additional steps to provide this information or these objects to the structure.

[0205] Additional inking step

[0206] It is possible to ink at least one external surface of at least one layer of the structure, such as the central layer, intermediate layers or external layers.

[0207] Indeed, it is known that identity cards, for example, contain inscriptions made with very specific inks to attest to the authenticity of the card.

[0208] Preferably, the process according to the invention includes an inking step on the outer surface 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 specifically, this step is performed before the film assembly step.

[0209] When the intermediate layer is inked, the outer layer has a role of protecting these inscriptions placed on the outer face of the intermediate layer.

[0210] 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 possibly after the cooling step.

[0211] Additional engraving step

[0212] 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 possibly after the cooling step.

[0213] Additional step of cutting the middle layer

[0214] 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.

[0215] 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.

[0216] Use 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.

[0217] The invention will be explained in more detail in the examples that follow.

[0218] EXAMPLES

[0219] Example 1 l. Preparation of compositions

[0220] 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.

[0221] These compositions were prepared by extrusion using 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 were introduced into the main hopper located on the first barrel of the extruder.

[0222] Table 1 BESHVO, whose inherent viscosity is 1.45, and whose glass transition temperature is between 40 and 60°C.

[0223] (2) PA11 B is a PA 11 KNO, whose inherent viscosity is 1.4, and whose glass transition temperature is between 40 and 60°C.

[0224] (3) PA11 C is a PA 11 BESNO 600, and whose glass transition temperature is between 40 and 60°C.

[0225] (4) The A-type glass fibers are marketed under the trade name Lanxess MF7982, sold by Lanxess, with an average size of 150 µm. The aspect ratio is 10.7.

[0226] (5) B-type glass fibers are marketed under the trade name Lanxess MF7904, sold by Lanxess, with an average size of 50 µm. The aspect ratio is 3.6. (6) Lanxess C-glass fibers are marketed under the trade name Lanxess CS MF7928, sold by Lanxess, in a size of 4.5 mm. These fibers are then milled to obtain an average size of 400 µm. The aspect ratio is 36.

[0227] (7)The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarole EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0228] Table 2

[0229] (1) PA11 A is a BESHVO, whose inherent viscosity is 1.45, and whose glass transition temperature is between 40 and 60°C.

[0230] (2) PA MXD10 is an XMFO polyamide sold by ARKEMA, whose glass transition temperature is between 50 and 70°C.

[0231] (3) PA11 B is a PA 11 KNO, whose inherent viscosity is 1.4, and whose glass transition temperature is between 40 and 60°C.

[0232] (4) PA11 C is a PA 11 BESNO 600, and whose glass transition temperature is between 40 and 60°C.

[0233] (5)B-type glass fibers are marketed under the trade name Lanxess MF7904, sold by Lanxess, with an average size of 50 µm. The aspect ratio is 3.6.

[0234] (6) The talc is marketed under the trade name Jetfine 3CA, sold by Imerys. The form factor is 3.4.

[0235] (7) The talc is marketed under the trade name HAR W92 and sold by Imerys. The form factor is 4.8.

[0236] (8) The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarole EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0237] The properties of the compositions are measured according to the following protocols:

[0238] Measurement of melting point

[0239] 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:

[0240] Equilibrium at -40°C

[0241] Initial heating from -40°C to 270°C at 20°C / min

[0242] Cooling from 270°C to -40°C at 20°C / min

[0243] Second heating from -40°C to 270°C at 20°C / min

[0244] In order to disregard the thermal history of the material, the value at the second heating is recorded.

[0245] Measurement of Young's modulus

[0246] 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:

[0247] Dynamometer: Instron

[0248] Test specimens: ISO 527-1A

[0249] Test speed: 1 mm / min (modulus), then 50 mm / min (continuous and axial at break)

[0250] Jaw: Pneumatic

[0251] Distance between jaws: 115 mm

[0252] Extensometer: mechanical (L0=75mm)

[0253] Force cell: 10 kN

[0254] Temperature: 23°C

[0255] Storage: 15 days at 23°C at 50% relative humidity.

[0256] MFI Measurement

[0257] The MFI of these diapers is measured according to ASTM 1238-2020 at 235°C and 2.16 kg.

[0258] 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.

[0259] 2. Film preparation

[0260] Polymer films are made by extrusion casting.

[0261] Cast extrusion is the extrusion of molten polymer using a single screw extruding 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 for achieving the desired thickness and width.

[0262] Extrusion is carried out on a COLLIN brand line, with a 45 mm diameter extruder whose length is 25 times the diameter. The extrusion temperatures are set to obtain a material temperature of 230 to 240°C.

[0263] The film thickness is 150 µm.

[0264] 3.Evaluation of the processability of films

[0265] The following properties are evaluated as follows:

[0266] It is possible to perform an extrusion step using a casting process.

[0267] The possibility of carrying out an extrusion step via a cast process from the tested compositions is evaluated.

[0268] O means yes: The films obtained are satisfactory in terms of thickness uniformity. N means no: The films have holes and / or imperfections. They tear during the stretching stage.

[0269] Dimensional and structural quality / surface appearance

[0270] The surface appearance of films obtained during extrusion casting is defined visually. Surface roughness defects in the film are observable to the naked eye by a person skilled in the art.

[0271] Table 3

[0272] Table 4

[0273] 4. Conclusion

[0274] The specific choice of materials makes it possible to obtain a material in a molten state that can be extruded via a casting process, which makes it possible to obtain films without surface defects.

[0275] Example 2 l. Preparation of compositions

[0276] The following compositions were prepared for the purpose of manufacturing the structures described below.

[0277] 1.1. Composition of the outer layers

[0278] The compositions were prepared from the compounds listed in Table 5 below.

[0279] These compositions were prepared by extrusion using 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 were introduced into the main hopper located on the first barrel of the extruder.

[0280] Table 5

[0281] (1) PA11 B is a PA 11 KNO with an inherent viscosity of 1.4, and a glass transition temperature between 40 and 60°C.

[0282] (2)PA11 A is a PA 11 BESHVO with an inherent viscosity of 1.45, and a glass transition temperature between 40 and 60°C.

[0283] (3) Platamid is a Platamid reference HX2507 sold by ARKEMA.

[0284] (4) The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarole EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0285] The properties of the compositions are measured according to the following protocols:

[0286] Measurement of melting point

[0287] 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.

[0288] The following program was followed for all the measures presented in this report:

[0289] Equilibrium at -40°C

[0290] Initial heating from -40°C to 270°C at 20°C / min

[0291] Cooling from 270°C to -40°C at 20°C / min

[0292] Second heating from -40°C to 270°C at 20°C / min

[0293] In order to disregard the thermal history of the material, the value at the second heating is recorded.

[0294] Transmittance measurement

[0295] 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:

[0296] - Accessory: Integration sphere (transmission including diffusion)

[0297] - Spectral range 800-200 nm

[0298] - Speed: 60 nm / min

[0299] - 1 nm bandwidth

[0300] - Scale: Transmittance

[0301] MFI Measurement

[0302] The MFI of these diapers is measured according to ASTM 1238-2020 at 235°C and 2.16 kg.

[0303] 1.1. Composition of the intermediate and central layers

[0304] The compositions were prepared from the compounds listed in Table 6 below. These compositions were prepared by extrusion using 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 250°C.

[0305] The polyamides and stabilizer are introduced into the main hopper located on the first barrel of the extruder. The fiberglass and talc are introduced via a lateral feeder on barrel 5.

[0306] Table 6

[0307] (!) PAH A es t un BESHVO, whose inherent viscosity is 1.45, and whose glass transition temperature is between 40 and 60°C.

[0308] (2) PA MXD10 is an XMFO polyamide sold by ARKEMA, whose glass transition temperature is between 50 and 70°C.

[0309] (3) The talc is marketed under the trade name HAR W92 and sold by Imerys. The form factor is 4.8.

[0310] (4) The stabilizer is a mixture of ADK Stab AO 40; ADK stab 2112 and Palmarole EXP 242 marketed under the trade name ADK Stab CB 132 CB sold by ADEKA polymer additive Europe.

[0311] 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.

[0312] 1.2. Composition of binder layers

[0313] The binder compositions used in the structures below are commercial products.

[0314] Orevac 18342 N is a maleic anhydride-grafted high-density polyethylene (HDPE) sold by SK Functional Polymer. It has a melting point of 3.5 g / 10 min and a melting point of 125 °C. The product is designated by O in Table 2 below.

[0315] 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 / 10 min and a melting point of 96 °C. The product is designated by L in Table 2 below.

[0316] MFI Measurement

[0317] MFI is measured according to ASTM 1238-2020 at 190°C, 2.16 kg for binder layers.

[0318] The melting temperature of the binder layer is measured according to the method described above in section 1.1. Generally, the MFI and Tf values ​​are provided by the manufacturers. These values ​​are available in the TDS (Technical Specifications) of the products.

[0319] 2. Preparation of the structures

[0320] The structures are prepared according to the following protocol: The layers are extruded as films. The extruded layers are produced using a Collin 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. The films are stacked on top of each other. The stacked films are compressed at 135°C for 20 minutes under a pressure of 15 bar. The consolidated structure is then cooled to 23°C for 20 minutes at a pressure of 15 bar.

[0321] The consolidated structures are then removed from the press and are ready for use.

[0322] The structures have a thickness of 840 µm before compression and 800 µm 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.

[0323] 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:

[0324] Table 7

[0325] 3. Evaluation of structures

[0326] The following physicochemical properties are evaluated on the structures described in Table 7:

[0327] Measurement of adhesive performance

[0328] The adhesion between the layers is measured according to the ISO 10373-1-2020 standard.

[0329] Adherence is measured on films

[0330] Outer layer / Binder / Intermediate layer and

[0331] On Central Layer / Binder / Intermediate Layer.

[0332] The lower of these two measurements is retained.

[0333] An adhesion greater than 5 N / cm is acceptable for this application.

[0334] Measurement of the traction modulus

[0335] 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.

[0336] A tensile modulus for the structure greater than 1 GPa is acceptable for this application.

[0337] 4. Results The results of the properties evaluated on the structures are shown in Table 8 below:

[0338] Table 8

[0339] 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.

[0340] Table 9

[0341] 4. Conclusions

[0342] The results show that the structures according to the invention are satisfactory in terms of interlayer adhesion and rigidity. Furthermore, their chemical compositions make them fully recyclable.

Claims

Demands 1. Composition including: -a polyamide matrix comprising predominantly 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 load having a form 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, 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, as well as 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, PA12, PA1010 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 glass 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. Structure according to any one of claims 11 to 13, characterized in that it comprises: -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, -an intermediate layer consisting of a composition as described in any one of claims 1 to 10, -a central layer consisting of a composition as described in any one of claims 1 to 10, -an intermediate layer consisting 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, -a step of drawing the molten material through the air, -a cooling stage 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 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.

17. Use of the structure as defined in any one of claims 11 to 14 as a data-carrying card, such as a card for securing an identity electronic, 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.

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