POLYAMIDES POLYDISPERSES

Abstract

The present invention relates to a polyamide composition comprising, by weight: (a) 35 to 100% of a polyamide component comprising, by weight relative to the total weight of the polyamide component: 50% to 95% of at least one polyamide A, 5 to 50% of at least one polyamide B different from polyamide A, (b) 0 to 65% of fillers, (c) 0 to 30% of at least one impact modifier, (d) 0 to 15% of at least one plasticizer, and (e) 0 to 5% of at least one additive, the sum of constituents (a) to (e) being equal to 100%, wherein the polyamide component (a) has a dispersity (D) greater than 2.25, in particular greater than 2.35.

Description

Title of the invention: POLYDISPERSE POLYAMIDES

[0001] The invention relates to polyamide compositions, their use and their preparation process. Previous technique

[0002] Polyamides are conventionally prepared by polycondensation of lactam, amino acid, diamine and dicarboxylic acid, or mixtures thereof. The virgin polyamides thus prepared generally exhibit, before processing, a molar mass dispersity or polydispersity (D) of between 1.6 and 2.1.

[0003] These polyamides are useful for forming articles shaped by traditional processes such as extrusion, film blowing, or injection molding. These various shaping processes generate a significant amount of waste and production scrap. Furthermore, the shaped articles are discarded after use, forming what is known as "post-consumer" waste. Until now, this waste was most often collected without sorting for disposal by incineration or landfill.

[0004] In order to avoid depleting the planet's resources and reduce environmental impact, efforts are now underway to recycle as much production waste or discarded manufactured articles as possible in order to recover the polymer and reuse it, for example in extrusion or injection molding processes. However, recycling presents a particular challenge: the need to separate the different polymers to be recycled in order to obtain a recycled polymer with good properties and therefore value. Pre-sorting the waste is a tedious step whose cost significantly impacts the economic viability of recycling. Summary of the invention

[0005] There is therefore a need for polyamide compositions, particularly from recycled materials, which have value but require little prior sorting.

[0006] However, it has now been unexpectedly found that compositions comprising several polyamides forming a component with a dispersity (D) greater than 2.25 exhibit improved mechanical properties, particularly in terms of cold shock resistance, yield strength and fatigue resistance, making them particularly interesting for the manufacture of injected parts.

[0007] The present invention therefore relates to a polyamide composition comprising:

[0008] (a) 35 to 100% of a polyamide component comprising, by weight relative to the Total weight of the polyamide component: a. 50% to 95% of at least one polyamide A, b. 5 to 50% of at least one polyamide B different from polyamide A,

[0009] (b) from 0 to 65% of charges,

[0010] (c) from 0 to 30% of at least one shock modifier,

[0011] (d) from 0 to 15% of at least one plasticizer, and

[0012] (e) of 0 to 5% of at least one additive,

[0013] the sum of constituents (a) to (e) being equal to 100%, wherein said polyamide component (a) has a dispersity (D) greater than 2.25, in particular greater than 2.35, in particular between 2.5 and 15.

[0014] These compositions can be manufactured from unsorted or partially sorted recyclable materials, since a high dispersibility is desired, achieved by mixing polyamide batches from various sources. These compositions can therefore be manufactured by recycling different polyamide batches together to produce a composition with the desired properties, which consequently has an attractive market value. Thus, it is possible to avoid finely separating the polyamide batches, whether they are objects or production waste.

[0015] Preferably, the polyamide component (a) of the polyamide composition comprises at least 50%, advantageously 75%, preferably 95%, in particular 100% aliphatic polyamide.

[0016] Advantageously, the polyamide component (a) has a C / N ratio greater than or equal to 6.5, in particular greater than or equal to 7.5, especially greater than or equal to 8.5, more particularly greater than or equal to 9.5.

[0017] Furthermore, the polyamide component (a) preferably comprises less than 1000 ppm of catalyst and / or polyamides having non-reactive end-chain functions and / or polyamides having an NH2 / COOH end-chain function ratio greater than 1. Such a polyamide component advantageously allows obtaining a composition free of species resulting from transamidification reactions.

[0018] Preferably, polyamides A and B have an inherent viscosity difference greater than 0.1, in particular greater than 0.2, especially greater than 0.4.

[0019] The polyamide composition advantageously has an inherent viscosity of less than 1.7, in particular less than 1.5, notably less than 1.3.

[0020] Advantageously, the polyamide component (a) comprises at least 30% recycled polyamide.

[0021] The recycled polyamide preferably has one or more functions resulting from oxidation reactions selected from among the primary amide, nitrile, methyl group at the end of the chain, alkene, formamide, imide, carboxylic acid and alcohol functions, in a molar ratio with respect to the amide functions greater than that of the same polyamide constituting a non-used object that has never been used. The molar ratio of functional groups resulting from oxidation reactions relative to secondary amide functional groups may range from 0.0001 to 0.3. More specifically, the molar ratio of imide functional groups relative to secondary amide functional groups may range from 0.0005 to 0.02, particularly from 0.001 to 0.08, and especially from 0.005 to 0.05. The molar ratio of carboxylic acid functional groups relative to secondary amide functional groups may range from 0.0005 to 0.02, particularly from 0.001 to 0.08, and especially from 0.005 to 0.05. The molar ratio of alcohol functions to secondary amide functions can range from 0.0005 to 0.02, in particular from 0.001 to 0.08, especially from 0.005 to 0.05. The molar ratio of nitrile functions to secondary amide functions can range from 0.0005 to 0.02, in particular from 0.001 to 0.08, especially from 0.005 to 0.05.

[0022] According to a second aspect, the invention aims at the use of such a composition for the manufacture of an article by injection.

[0023] According to a third aspect, the invention relates to a method for preparing a composition comprising the step of:

[0024] (i) mix the constituents (a) to (e) in the molten state, in particular in an extruder.

[0025] According to a fourth aspect, the invention relates to a method of preparing the composition, in which step (i) is carried out with a residence time of less than five minutes.

[0026] According to a fifth aspect, the invention relates to a method for implementing such a composition, comprising an extrusion or injection step of said composition at a temperature below 300 °C, preferably 280 °C.

[0027] [Definitions]

[0028] Throughout the description, unless otherwise stated, percentages are expressed as weight relative to the total weight of the composition.

[0029] The nomenclature used to designate polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art.

[0030] The term "polyamide" refers to both homopolyamide and copolyamide. By extension, this term also generally refers to copolymers containing amide units.

[0031] The expression "a polyamide B different from polyamide A" means that polyamide B differs from polyamide A) at the level of its molecular structure, in particular by its number-average molecular weight (Mn), its dispersity, the content of end-chain functions and / or its C / N ratio (or average C / N ratio).

[0032] The term “dispersity” refers to the width of the chain length distribution of a polymer. It is given by the ratio between the weight-average molecular mass Mw and the number-average molecular mass Mn. The average molecular masses Mn and Mw are measured by size-exclusion chromatography, in particular by gel permeation chromatography, according to ISO 16014-1:2012, for example according to the following protocol: The polyamide is solubilized at a concentration of 2 g / L in hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate for 24 h at room temperature (20°C).The resulting solution is then filtered through a PTFE membrane with a porosity of 0.2 µm, and then injected at a flow rate of 1 mL / min into a liquid chromatography system equipped with a set of PFG columns from Polymer Standards Service consisting of a pre-column measuring 50 x 8 mm, a 1000 Å column measuring 300 x 8 mm with a particle size of 7 µm, and a 100 Å column measuring 300 x 8 mm with a particle size of 7 µm. Molar masses are measured by the refractive index and expressed in PMMA equivalents, used as a calibration standard, and then converted to g / mol.

[0033] The term "C / N ratio" refers to the ratio of the number of carbon atoms to nitrogen atoms in a given polyamide unit. When discussing blends of polyamides (or copolyamides), an average C / N ratio is considered, calculated on the basis of the C / N ratio of each constituent of the blend or unit of the copolyamide, weighted by its respective weight in the blend or copolyamide.

[0034] The average C / N ratio of a polyamide composition can be determined in particular by proton NMR spectroscopy, by dividing the area of ​​the peaks corresponding to the protons of the CH2 groups of the polyamide by the area corresponding to the protons of the NH groups (or possibly of the CH2 groups in alpha position of the amide functions). Description of implementation methods Composition

[0035] According to the invention, the polyamide composition comprises, by weight:

[0036] (a) 35 to 100% of a polyamide component comprising, by weight relative to the Total weight of the polyamide component: a. 50% to 95%, preferably 55% to 90%, in particular 60% to 85% and especially 70% to 80% of at least one polyamide A, b. 5 to 50%, preferably 10 to 45%, in particular 15 to 40%, and especially 20 to 30% of at least one polyamide B different from polyamide A,

[0037] (b) from 0 to 65%, preferably 5 to 60%, in particular 10 to 50%, especially 20 to 40% and in particular 25 to 30% in charges,

[0038] (c) from 0 to 30%, in particular 0 to 20% and especially 0 to 10% of at least one altering shock,

[0039] (d) from 0 to 15%, in particular 0 to 5% and especially 0 to 1.5% of at least one plasticizer, and

[0040] (e) from 0 to 5%, in particular 0.1 to 5%, notably 0.1 to 2% of at least one additive,

[0041] the sum of the constituents (a) to (e) being equal to 100%, in which the component polyamide (a) of the composition has a dispersity (D) greater than 2.25, in particular greater than 2.35, in particular between 2.5 and 15.

[0042] Preferably, the polyamide component (a) has a dispersity (D) of 3 to 13, in particular 4 to 12, in particular 5 to 10. Polyamide component (a)

[0043] According to the invention, the composition comprises 35 to 100% by weight of polyamide component (a). The polyamide component (a) comprises at least one polyamide A and at least one polyamide B distinct from polyamide A.

[0044] Polyamides A and B respectively comprise or are preferably made up of a repeating motif selected from a motif obtained from the polycondensation of at least one C4-C36 amino acid, a motif obtained from the polycondensation of at least one C4-C36 lactam and an XY motif obtained from the polycondensation: - of a diamine, in particular chosen from a linear or branched aliphatic diamine, a cycloaliphatic diamine and an aromatic or arylaliphatic diamine or a mixture thereof, and - of a dicarboxylic acid, in particular chosen from an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid or a mixture thereof, - said diamine and said diacid comprising respectively from 4 to 36 carbon atoms.

[0045] In a first embodiment, the repeating motif is obtained by the polycondensation of at least one aminocarboxylic acid at C4-C36, and in particular at C9-Ci2. Preferably, the aminocarboxylic acid is chosen from 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously it is 11-aminoundecanoic acid.

[0046] In a second embodiment, the repeating motif is obtained by the polycondensation of a lactam at C4-C36, and in particular at C9-Ci2. Advantageously, the lactam is chosen from decanolactam, undecanolactam and laurolactam or lauryllactam; preferably, the repeating motif is derived from lauryllactam.

[0047] However, it is entirely possible to implement a mixture of two or more aminocarboxylic acids, a mixture of two or more lactams, or a mixture of one, two, or more aminocarboxylic acids with one, two, or more lactams. More particularly preferred, however, is the repeating motif obtained by polycondensation of a single aminocarboxylic acid or a single lactam.

[0048] In another variant, the polyamide comprises or is made up of a repeating XY pattern.

[0049] The XY repeating motif can be obtained from the polycondensation of a diamine, in particular an aliphatic diamine, linear or branched, a cycloaliphatic diamine, aromatic or arylaliphatic, alone or in a mixture, and at least one dicarboxylic acid, in particular selected from an aliphatic dicarboxylic acid, a cycloaliphatic dicarboxylic acid and an aromatic dicarboxylic acid, alone or in a mixture. Preferably, the XY repeating motif is obtained from the polycondensation of an aliphatic diamine with an aliphatic dicarboxylic acid.

[0050] Said diamine preferably comprises 4 to 36, advantageously 6 to 18, in particular 9 to 18, and especially 6 to 12 carbon atoms.

[0051] The linear aliphatic diamine preferably has the formula H2N-(CH2)X-NH2. It may be chosen, for example, from butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, hexadecanediamine, octadecanediamine, and octadecenediamine. The linear aliphatic diamines mentioned may be bio-based within the meaning of ASTM D6866.

[0052] The branched aliphatic diamine may in particular be chosen from 2-methyl-pentanediamine, 2-methyl-1,8-octanediamine or trimethylene (2,2,4 or 2,4,4)hexanediamine.

[0053] The cycloaliphatic diamine may be chosen from those indicated in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405). Preferred are bis(3,5-dialkyl-4-aminocyclohexyl)-methane, bis(3,5-dialkyl-4-aminocyclohexyl)ethane, bis(3,5-dialkyl-4-aminocyclohexyl)-propane, bis(3,5-dialkyl-4-aminocyclo-hexyl)-butane, bis-(3-methyl-4-aminocyclohexyl)-methane or 3'-dimethyl-4,4'-diamino-dicyclohexyl-methane also known as "BMACM" or "MACM" (B), p-bis(aminocyclohexyl)-methane also known as "PACM" (P), isopropylidenedi(cyclohexylamine) (PACP), isophoronediamine (noted IPD) and 2,6-bis(aminomethyl)norbornane (BAMN) or bis(aminomethyl)cyclohexane (BAC).

[0054] The arylaliphatic diamine can, for example, be chosen from 1,3-xylylene diamine and 1,4-xylylene diamine.

[0055] The dicarboxylic acid preferably comprises 4 to 36, advantageously 6 to 18 and in particular 6 to 12 carbon atoms.

[0056] Preferably, the dicarboxylic acid is aliphatic, and in particular linear or branched. A linear aliphatic dicarboxylic acid is particularly preferred.

[0057] The linear aliphatic dicarboxylic acid may in particular be selected from succinic acid (4), pentanedioic acid (5), adipic acid (6), heptanedioic acid (7), octanedioic acid (8), azelaic acid (9), sebacic acid (10), undecanedioic acid (11), dodecanedioic acid (12), brassylic acid (13), tetradecanedioic acid (14), hexadecanedioic acid (16), octadecanedioic acid (18), octadecenedioic acid (18), eicosanedioic acid (20), docosanedioic acid (22) and fatty acid dimers containing 36 carbon atoms. The fatty acid dimers mentioned above are dimerized fatty acids obtained by oligomerization or polymerization of long-chain unsaturated monobasic fatty acids (such as linoleic acid and oleic acid), as described in particular in document EP 0 471 566.

[0058] The aromatic dicarboxylic acid can be chosen in particular from terephthalic acid (denoted T), isophthalic acid (denoted I) and a naphthalenic acid (denoted N).

[0059] Preferably, the polyamide component (a) comprises at least 50%, advantageously 75%, preferably 95%, in particular 100% by weight of aliphatic polyamide.

[0060] According to the invention, the polyamide component (a) has a dispersity (D) greater than 2.25. Advantageously, the dispersity (D) of the polyamide component (a) is greater than 2.35, in particular from 2.5 to 15, and more preferably from 3 to 13, in particular from 4 to 12, especially from 5 to 10, preferably from 6 to 9, and most particularly from 7 to 8. In one embodiment, the dispersity (D) of the component (a) is from 2.5 to 5. In another embodiment, the dispersity (D) is from 5 to 7.5. In yet another embodiment, the dispersity (D) is from 7.5 to 10. In yet another embodiment, the dispersity (D) is from 10 to 12.5. According to another embodiment, the dispersion (D) is from 12.5 to 15.

[0061] Advantageously, the polyamide component (a) has an average C / N ratio greater than or equal to 6.5, in particular greater than or equal to 7.5, in particular greater than or equal to 8.5, more particularly greater than or equal to 9.5 and in particular greater than or equal to 10 and preferably greater than or equal to 11.

[0062] Preferably, the polyamide component (a) has an average molecular mass in number Mn ranging from 10000 g / mol to 85000 g / mol, in particular from 10000 g / mol to 60000 g / mol, in particular from 10000 g / mol to 50000 g / mol, even more preferably from 12000 g / mol to 50000 g / mol.

[0063] These Mn values ​​may correspond to an inherent viscosity greater than or equal to 0.8, as determined in m-cresol according to ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and the temperature being 20°C).

[0064] In order to minimize the risk of a reaction, it is also preferred that the polyamide component (a) contain less than 1000 ppm of polycondensation catalyst, particularly phosphorus-based. In particular, the catalyst content in the polyamide component (a) may be less than 500 ppm, preferably less than 100 ppm.

[0065] The nature of the catalyst can be determined, in particular, by GC-MS spectroscopy. For a catalyst comprising protons, such as phosphorus catalysts: The phosphorus content and its nature can be determined by 1H NMR spectroscopy, for example, on an AVANCE 400 NEO spectrometer. The samples are solubilized at room temperature in an HFIP / CD2Cl mixture (in a 3:1 v / v ratio). The sample size is approximately 500 mg. The analysis is performed using the method without an internal standard. From the proton NMR spectrum, the mass content of H3PO2 can be determined relative to the composition.

[0066] Preferably, the polyamide component (a) also comprises at least 50% by weight, preferably at least 70% by weight, and particularly at least 90% by weight, or even 100% by weight, of polyamide having non-reactive end-chain functionalities. The term "non-reactive end-chain functionalities" means functionalities that do not react with a carboxylic acid or a primary amine in reactive extrusion. These functionalities may be selected, in particular, from among alkyl and alcohol functionalities; preferably, they are alkyl functionalities.

[0067] Finally, the polyamide component (a) preferably has a ratio between the end-chain amine and carboxylic acid (NH2 / COOH) functions greater than 1, and preferably greater than 1.01.

[0068] The concentration of NH2 groups at the end of the chain can be measured using a potentiometric titration. This titration can, for example, be carried out as follows: the polyamides are first dissolved in m-cresol at 80°C, and then the terminal NH2 groups are titrated with a perchloric acid solution. The concentration of COOH groups at the end of the chain can be determined by potentiometric analysis. A measurement protocol is detailed in the article "Synthesis and characterization of poly(copolyethers-block-polyamides) - II. Characterization and properties of the multiblock copolymers," Maréchal et al., Polymer, Volume 41, 2000, 3561-3580. The (NH2 / COOH) ratio is then obtained by dividing the two concentrations.

[0069] Preferably, polyamide A consists of a single homopolyamide. Even more preferably, polyamide B also consists of a single homopolyamide. More advantageously, polyamides A and B consist of an aliphatic semi-crystalline homopolyamide.

[0070] Preferably, polyamide B differs from polyamide A in the average molecular weight in number Mn. In particular, polymer B may have a Mn different from that of polyamide A by more than 3%, advantageously greater than 5%, and in particular greater than 10%.

[0071] Polyamide B may also differ from polyamide A in dispersity. In particular, polymer B may exhibit a dispersity that differs from that of polyamide A by more than 3%, advantageously more than 5%, and especially more than 10%.

[0072] Polyamide B may also differ from polyamide A in the content of end-chain functional groups. These functional groups may include amine or carboxylic acid groups. In particular, polymer B may have a different content of amine and / or carboxylic acid end-chain functional groups than polyamide A by more than 3%, advantageously more than 5%, and especially more than 10%.

[0073] Polyamide B may also differ from polyamide A in its average C / N ratio. In particular, polymer B may have an average C / N ratio that differs from that of polyamide A by more than 1, advantageously greater than 1.5, and especially greater than 2.

[0074] In one embodiment, polyamide B differs from polyamide A in molar mass, dispersity and C / N ratio by at least 1, for example the difference between the molar mass of polyamide A and that of polyamide B is greater than 3%, advantageously greater than 5% and the difference between the dispersity of polyamide A and that of polyamide B is greater than 3%, advantageously greater than 5%, and the difference between the C / N ratio of polyamide A and that of polyamide B is greater than 1.

[0075] In one embodiment, polyamide B differs from polyamide A in molar mass, dispersity, chain ends and C / N ratio, for example the difference between the molar mass of polyamide A and that of polyamide B is greater than 3%, advantageously greater than 5% and the difference between the dispersity of polyamide A and that of polyamide B is greater than 3%, advantageously greater than 5%, the chain ends of polyamides A and B are different and the difference between the C / N ratio of polyamide A and that of polyamide B is greater than 1.

[0076] Advantageously, the polyamide component (a) consists of polyamides whose inherent viscosity difference, between the polyamide with the lowest inherent viscosity and the one with the highest inherent viscosity, is greater than 0.1, in particular greater than 0.2, notably greater than 0.4. Preferably, the composition The polyamides of the invention have an inherent viscosity of less than 1.7, in particular less than 1.5, especially less than 1.3. According to one embodiment, the composition has an inherent viscosity between 0.9 and 1.7, for example between 1.0 and 1.3. The inherent viscosity is determined in m-cresol according to ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and the temperature being 20°C).

[0077] Preferably, the polyamide component (a) comprises at least 30%, in particular at least 40%, in particular at least 50%, in particular at least 60%, more particularly at least 70%, even more particularly at least 80%, and most particularly 90% by weight of recycled polyamide.

[0078] Particularly advantageously, the polyamide component (a) of the composition is made up of 100% recycled polyamide.

[0079] Preferably, the recycled polyamide in the composition is characterized in that it has functional groups resulting from oxidation reactions selected from primary amides, nitriles, methyl groups at the end of the chain, alkenes, formamides, imides, carboxylic acids and alcohols and mixtures thereof, in a molar ratio relative to the amide functional groups greater than that of the same polyamide constituting a new, unused article. These functional groups resulting from oxidation reactions may be present in the recycled polyamide in a molar ratio relative to the secondary amide functional groups greater than 10%, for example greater than 100%, for example greater than 150%, for example greater than 300%, relative to that of the same virgin polyamide.

[0080] During the use of a manufactured object, new species resulting from oxidation mechanisms, including primary amide, nitrile, methyl end-chain, alkene, formamide, imide, carboxylic acid, and alcohol functional groups, may appear in the polyamides constituting said objects. These functional groups appear due to UV radiation, heat, or a reaction with a compound with which said object is in contact, for example, gasoline, sunscreen, lubricants, etc.

[0081] These functions can be detected by infrared spectrometry or NMR. The concentrations can be measured by proton NMR in dichloromethane-d2, by adding HFIP (hexafluoroisopropanol) to solubilize the polyamide. For example, 20 mg of polymer can be dissolved in 0.7 mL of solvent with an HFIP / CD2C12 ratio of 1 / 3.

[0082] Some of the functions mentioned above can be observed by 13C NMR. Thus, the line at 36 ppm corresponds to the α-CH2 of the primary amide, and the one at 34 ppm corresponds to the α-CH2 of the carboxylic acid. These species can be quantified by integrating the area under the lines and comparing them to the area under the line at 37.1 ppm corresponding to the secondary amide. Similarly, the lines corresponding to the carbonyl groups of the primary amide, carboxylic acid, and secondary amide functions are observed at 181.2 ppm, 179.6 ppm, and 177.4 ppm, respectively. The line at 16.7 ppm corresponds to the α-CH2 of the nitrile group. The formamide group gives a chemical shift at 163.0 ppm and 166.3 ppm.

[0083] Other functional groups mentioned above can be observed by proton NMR (¹H NMR) in the solvent HFIP / CD2C12 as described above. The CHO group line of the formamides is observed at 7.92 and 8.01 ppm. The line corresponding to the α-CH2 groups of the primary amides can be observed at 2.30 ppm. The 0.9 ppm line corresponds to the CH3 group of the type CH3-(CH2)n. The line at 2.40 ppm corresponds to the α-CH2 group of the nitrile functional group. Similar to what is described for carbon NMR, the ratios of new functional groups to secondary amides can be determined by integrating the area under the lines and comparing them to the area under the line corresponding to the α-CH2 group of the secondary amide (2.20 ppm).

[0084] Furthermore, in infrared spectroscopy, the absorption band from 1700 to 1740 cm⁻¹ corresponds to an imide, that from 1680 to 1720 cm⁻¹ to the carbonyl group of the carboxylic acid, and that from 3580 to 3670 cm⁻¹ to the alcohol group of the carboxylic acid. The absorption band from 3580 to 3670 cm⁻¹ corresponds to the free alcohol group. The amide group is characterized, on the one hand, by a pair of absorption bands from 3100 to 3500 cm⁻¹ and from 1560 to 1640 cm⁻¹, which correspond to the NH₂ group of the amide, and on the other hand, by the absorption band from 1650 to 1700 cm⁻¹, which corresponds to the carbonyl group of the amide.

[0085] The molar ratio of functions resulting from oxidation reactions relative to secondary amide functions can be from 0.0001 to 0.3.

[0086] The molar ratio of imide functions to secondary amide functions can be from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.05.

[0087] The molar ratio of carboxylic acid functions to secondary amide functions is preferably from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.05.

[0088] Preferably, said molar ratio of alcohol functions to secondary amide functions is from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.05.

[0089] Moreover, said molar ratio of primary amide functions to secondary amide functions is preferably between 0.0005 and 0.1, in particular between 0.001 and 0.08, in particular between 0.005 and 0.05.

[0090] Said molar ratio of nitrile functions with respect to secondary amide functions is preferably between 0.0005 and 0.1, in particular between 0.001 and 0.08, in particular between 0.005 and 0.05.

[0091] The molar ratio of alkene functions to secondary amide functions can be from 0.0005 to 0.1, in particular from 0.001 to 0.08, in particular from 0.005 to 0.05.

[0092] The molar ratio of formamide functions to secondary amide functions can be from 0.0005 to 0.1, in particular from 0.001 to 0.08, in particular from 0.005 to 0.05.

[0093] Finally, said molar ratio of methyl functions at the end of the chain relative to secondary amide functions is preferably between 0.0005 and 0.2, in particular between 0.001 and 0.08, in particular between 0.005 and 0.05. Charges (b)

[0094] The composition of the invention may comprise 0 to 65%, in particular 5 to 60%, in particular 10 to 50%, in particular 20 to 40% and in particular 25 to 30% by weight of fillers.

[0095] The charges can be chosen in particular from:

[0096] - Reinforcing fibers;

[0097] - Conductive fillers such as carbon black and carbon nanotubes;

[0098] - Flame retardant agents (HFFR);

[0099] - Fillers for reducing the density of the composition such as beads hollow glass;

[0100] - Heat-conducting charges, in particular selected from oxides of metals such as alumina (Al2O3), aluminosilicate (Al2SiO5) and ceramics such as boron nitride (BN) and aluminium nitride (AIN).

[0101] Reinforcing fibers are particularly preferred fillers. They can be of mineral, organic, or vegetable origin. Furthermore, reinforcing fibers can be coated or uncoated. Reinforcing fibers can therefore be coated with up to 0.1% by weight of an organic material (such as a thermosetting or thermoplastic resin) forming the coating.

[0102] Among the mineral-based fibers, we can mention carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, and silicon carbide fibers.

[0103] Among organic fibers, we can mention thermoplastic or thermosetting polymer-based fibers, such as semi-aromatic polyamide fibers, aramid fibers and polyolefin fibers.

[0104] Among the plant-based fibers, examples include natural fibers made from flax, hemp, lignin, bamboo, silk (particularly spider silk), sisal, and other cellulosic fibers, especially viscose. These plant-based fibers can be used pure, treated, or coated with a layer of coating to facilitate adhesion and impregnation of the thermoplastic polymer matrix.

[0105] Preferably, the reinforcing fiber is chosen from glass fibers, carbon fibers, basalt fibers and basalt-based fibers, in particular from carbon fibers and glass fibers and in particular glass fibers.

[0106] Glass fibers can have a circular or non-circular cross-section. Examples of non-circular fibers include elliptical, oval, cocoon, star, or flake cross-sections, as well as flat, cruciform, polygonal, or annular fibers. Advantageously, glass fibers have a circular cross-section. Glass fibers are notably of type E, R, S2, or T. Advantageously, glass fibers are of type E.

[0107] According to a preferred embodiment, the fillers are recycled fillers. For fillers containing glass, they may, in particular, be manufactured from industrial production waste or post-consumer recycled glass. The carbon fibers may, for example, come from cutting spools of expired long fibers, especially carbon fibers for the aerospace industry.

[0108] Advantageously, the fillers are chosen from glass fibers, in particular with a circular cross-section, and carbon fibers, in particular glass fibers, especially with a circular cross-section. Shock modifier (c)

[0109] The polyamide composition of the invention further comprises 0 to 30%, 0 to 20% and in particular 0 to 10% by weight of at least one shock modifier.

[0110] The shock modifier is advantageously a polymer having a flexural modulus of less than 100 MPa (measured according to ISO 178:2010, at 23°C with a relative humidity of RH50%), and a Tg of less than 0°C (measured according to ISO 11357-2:2013 at the inflection point of the DSC thermogram, at a heating rate of 20K / min).

[0111] In particular, it may be a polyolefin, or a PEBA, in particular a PEBA having a flexible PTMG segment.

[0112] The polyolefin may be functionalized or non-functionalized or be a mixture of at least one functionalized polyolefin and / or at least one non-functionalized polyolefin.

[0113] An unfunctionalized polyolefin can conventionally be a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, 1-butene, 1-octene, butadiene. Examples include:

[0114] - homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene;

[0115] - homopolymers or copolymers of propylene;

[0116] - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM);

[0117] - styrene / ethylene-butene / styrene block copolymers (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS); and

[0118] - copolymers of ethylene with at least one product selected from the salts or the esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (e.g. methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer can reach 40% by weight.

[0119] The functionalized polyolefin may in particular be a polymer of alpha olefins having reactive motifs (the functionalities); such reactive motifs are acid, anhydride, or epoxy functions. By way of example, one may cite the aforementioned polyolefins grafted or co- or ter-polymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid (the latter being able to be totally or partially neutralized by metals such as Zn, etc.) or even by anhydrides of carboxylic acids such as maleic anhydride. A functionalized polyolefin is for example a PE / EPR mixture, the weight ratio of which can vary widely, for example between 40 / 60 and 90 / 10, said mixture being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate for example of 0.01 to 5% by weight.

[0120] The functionalized polyolefin can be selected from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting ratio is, for example, from 0.01 to 5% by weight:

[0121] - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing, for example, 35 to 80% by weight of ethylene;

[0122] - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM);

[0123] - styrene / ethylene-butene / styrene block copolymers (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS);

[0124] - ethylene and vinyl acetate (EVA) copolymers, containing up to 40% in weight of vinyl acetate;

[0125] - ethylene and alkyl (meth)acrylate copolymers, containing up to 40% in weight of alkyl (meth)acrylate; and

[0126] - ethylene and vinyl acetate (EVA) and alkyl (meth)acrylate copolymers, containing up to 40% by weight of comonomers.

[0127] The functionalized polyolefin can also be selected from ethylene / propylene copolymers major in propylene grafted with maleic anhydride and then condensed with mono-amino polyamide (or a polyamide oligomer) (products described in EP-A-0342066).

[0128] The functionalized polyolefin may also be a co- or terpolymer of at least the following motifs: (1) ethylene, (2) alkyl (meth)acrylate or saturated carboxylic acid vinyl ester and (3) anhydride such as maleic anhydride or (meth)acrylic acid or epoxy such as glycidyl (meth)acrylate.

[0129] By way of example of functionalized polyolefins of this latter type, the following copolymers may be cited, where ethylene preferably represents at least 60% by weight and where the ter monomer (the function) represents, for example, from 0.1 to 10% by weight of the copolymer:

[0130] - ethylene / alkyl (meth)acrylate / (meth)acrylic acid copolymers or maleic anhydride or glycidyl methacrylate;

[0131] - ethylene / vinyl acetate / maleic anhydride or methacrylate copolymers glycidyl;

[0132] - ethylene / vinyl acetate or alkyl (meth)acrylate / acid copolymers (meth)acrylic or maleic anhydride or glycidyl methacrylate.

[0133] In the preceding copolymers, (meth)acrylic acid can be salified with Zn or Li.

[0134] The term "alkyl (meth)acrylate" in functionalized or non-functionalized polyolefins refers to methacrylates and alkyl acrylates in C1 to C8, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl-2-hexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0135] Furthermore, the aforementioned polyolefins can also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the aforementioned polyolefins with a difunctional reagent such as a diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins capable of reacting with each other.

[0136] The copolymers mentioned above can be copolymerized statistically or sequentially and have a linear or branched structure.

[0137] The molecular weight, MFI, and density of these polyolefins can also vary considerably, a fact that those skilled in the art will appreciate. MFI, short for Melt Flow Index, is the melt flow index. It is measured according to ASTM 1238.

[0138] Advantageously, the non-functionalized polyolefins are selected from homopolymers or copolymers of polypropylene and any homopolymer of ethylene or copolymer of ethylene and a higher alpha-olefin comonomer such as butene, hexene, octene, or 4-methyl-1-pentene. Examples include PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, and ultra-low-density PE. These polyethylenes are known to those skilled in the art to be produced by a "radical" process, by Ziegler-type catalysis, or, more recently, by so-called "metallocene" catalysis.

[0139] Advantageously, functionalized polyolefins are selected from any polymer comprising alpha olefin motifs and motifs bearing polar reactive functions such as epoxy, carboxylic acid, or carboxylic acid anhydride groups. Examples of such polymers include terpolymers of ethylene, alkyl acrylate, and maleic anhydride or glycidyl methacrylate, such as SKFP's Lotader®, or polyolefins grafted with maleic anhydride, such as SKFP's Orevac®, as well as terpolymers of ethylene, alkyl acrylate, and (meth)acrylic acid. Also included are homopolymers or copolymers of polypropylene grafted with a carboxylic acid anhydride and then condensed with polyamides or monoamino oligomers of polyamide. Plasticizer (d)

[0140] The polyamide composition of the invention also comprises 0 to 15%, in particular 0 to 5%, notably 0 to 1.5%, of at least one plasticizer.

[0141] The plasticizer can in principle be any plasticizer among those commonly used in polyamide-based compositions.

[0142] Advantageously, a plasticizer is used which has good thermal stability so that no fumes are formed during the mixing steps of the different polymers and the transformation of the composition obtained.

[0143] In particular, this plasticizer may be selected from: - Benzene sulfonamide derivatives such as n-butyl benzene sulfonamide (BBSA), ortho and para isomers of ethyl toluene sulfonamide (ETSA), N-cyclohexyl toluene sulfonamide and N-(2-hydroxypropyl) benzene sulfonamide (HP-BSA), - hydroxybenzoic acid esters such as ethyl-2-hexyl para-hydroxybenzoate (EHPB) and decyl-2-hexyl para-hydroxybenzoate (HDPB), - esters or ethers of tetrahydrofurfuryl alcohol such as oligoethyleneoxy-tetrahydrofurfuryl alcohol, and - esters of citric acid or hydroxymalonic acid, such as oligoethyleneoxymalonate.

[0144] A preferred plasticizer is n-butyl benzene sulfonamide (BBSA).

[0145] Another particularly preferred plasticizer is N-(2-hydroxy-propyl)benzenesulfonamide (HP-BSA). The latter has the advantage of preventing the formation of deposits at the screw and / or the extrusion die ("die tears") during an extrusion transformation step.

[0146] A mixture of plasticizers can obviously be used.

[0147] Preferably, the polyamide composition is free of plasticizer. Additives (e)

[0148] The polyamide composition also includes 0 to 5%, in particular 0.1 to 5%, notably 0.1 to 2% by weight of at least one additive.

[0149] The at least one additive may in particular be chosen from basic reagents, stabilizers, colorants, processing aids, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, waxes, flame retardant synergists, or a mixture thereof.

[0150] By way of example, the stabilizer may be a UV stabilizer, an organic stabilizer or more generally a combination of organic stabilizers, such as a phenol-type antioxidant (for example Irganox® 245 or 1098 or 1010 from Ciba-BASF), a phosphite-type antioxidant (for example Irgafos® 126 or Irgafos® 168 from Ciba-BASF), a HALS (Hindered Amine Light Stabiliser or hindered amine light stabilizer for example Tinuvin® 770 from Ciba-BASF), an anti-UV (for example Tinuvin® 312 from Ciba) or a phosphorus-based stabilizer. One can also use amine-type antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0151] This stabilizer can also be a mineral stabilizer, such as a copper-based stabilizer. Examples of such mineral stabilizers include copper halides and copper acetates. Other metals, such as silver, could also be considered, but these are known to be less effective. These compounds copper-based compounds are typically associated with alkali metal halides, particularly potassium.

[0152] In particular, the composition may include, as an additive (e), one or more basic compounds. Preferably, the basic reagent has a pKa greater than 7, advantageously 8, and preferably 9.

[0153] Advantageously, the basic reagent is chosen from stearates, carbonates, and hydroxides. Preferably, the basic reagent comprises a cation chosen from Ca²⁺, Na⁺, K⁺, Mg²⁺, and Cu²⁺. Preferred basic reagents are potassium hydroxide and sodium hydroxide.

[0154] The basic reagent is capable of reacting with carboxylic acid functions to form formula groups:

[0155] COO- X+

[0156] in which

[0157] X+ designates a cation, in particular a metallic cation, in particular chosen from Ca++, Na+, K+, Mg++ and Cu+.

[0158] Useful synergistic flame retardant agents are described in particular in WO2005121234.

[0159] They can be chosen from nitrogen synergists and phosphorus / nitrogen synergists.

[0160] Nitrogen synergists preferably include benzoguanamine, tris(hydroxyethyl)isocyanurate, allantoin, glycolurile, melamine, melamine cyanurate, dicyandiamide, guanidine, carbodiimides.

[0161] Nitrogen synergists preferably comprise melamine condensation products. By way of example, melamine condensation products are melem, melam or melon, or compounds of this type with a higher degree of condensation, or a mixture thereof, and, by way of example, may be prepared by the process described in US patent 5,985,960.

[0162] Phosphorus / nitrogen synergists may include reaction products of melamine with phosphoric acid or with condensed phosphoric acids, or include reaction products of condensation products of melamine with phosphoric acid or condensed phosphoric acids, or include a mixture of the specified products.

[0163] In one embodiment, the additives are chosen from antioxidants, colour pigments and flame retardant synergists, in particular nitrogen synergists, especially melamine-based.

[0164] According to another aspect, the present invention relates to the use of a composition as defined above for the manufacture of an article by injection, in particular a sporting article, an article of interest in the field of industry, electronics or optics.

[0165] According to yet another aspect, the present invention relates to a method for preparing a composition as defined above, comprising the step of (i) mixing the constituents (a) - (e) in the molten state. Preferably, this step (i), also called the compounding step, is carried out in an extruder. Advantageously, it is conducted with a residence time in the extruder of less than five minutes.

[0166] According to yet another aspect, the present invention relates to a method of implementing a composition as defined above, characterized in that it comprises a step of extrusion or injection of said composition at a temperature below 300 °C, preferably 260 °C, in particular with a residence time of less than 5 minutes. EXAMPLES

[0167] The polyamide compositions in the examples below were prepared by standard compounding according to the following protocol.

[0168] Compounding for the preparation of granules of compositions

[0169] Coperion ZSK 26 MC type twin-screw extruder with at least 1 lateral feed channel for raw materials

[0170] Machine temperature: 270°C

[0171] Screw speed: 250 rpm

[0172] Extruder outlet flow rate: 20 kg / h Transformation

[0173] In order to evaluate the mechanical properties, the granules obtained above are transformed into test specimens measuring 80 mm x 10 mm x 4 mm by injection molding. The following parameters were used:

[0174] - ENGEL VICTORY 500 hydraulic press, 160T

[0175] - Injection temperature (supply / nozzle): 240 / 260 °C for EU, EI2 and EC1 and 280 / 300 °C for EC2

[0176] - Mold temperature: 50°C

[0177] Impact resistance was determined according to ISO 179-1: 2010 (Charpy impact) on notched 80mm x 10mm x 4mm specimens, at a temperature of -30°C + / -2°C on dry samples. Dispersion measurement

[0178] Dispersion was determined as the ratio of the weight-average molecular mass Mw to the number-average molecular mass Mn. The number-average molecular mass Mn and the weight-average molecular mass Mw were measured by gel permeation chromatography according to the following protocol, based on ISO 16014-1:2012.

[0179] The polyamide is solubilized to a concentration of 2 g / L in hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate during 24 h at room temperature (20°C). The resulting solution is then filtered through a PTFE membrane with a porosity of 0.2 µm, and then injected at a flow rate of 1 mL / min into a liquid chromatography system equipped with a set of PFG columns from Polymer Standards Service consisting of a pre-column measuring 50 x 8 mm, a 1000 Å column measuring 300 x 8 mm with a particle size of 7 µm, and a 100 Å column measuring 300 x 8 mm with a particle size of 7 µm. Molar masses are measured by the refractive index and are expressed in PMMA equivalents, used as a calibration standard, and then converted to g / mol.

[0180] The results are presented in Table 1 below.

[0181] [Table 1]: Composition of the formulations studied EU [% by weight] EI2 [% by weight] EC1 [% by weight] EC2 [% by weight] PA 11 with inherent viscosity 1.53 30 - - - PA 11 with inherent viscosity 0.96 70 - 100 - PA 11 from a blend of recycled products, with inherent viscosity 0.95 - 100 - - PA 11 / 10T with inherent viscosity 1.13 - - - 100 Dispersal (Mw / Mn) 2.7 2.5 1.7 2.75 Notched impact at -30 °C, resilience (kJ / m2) 21 19 11.2 8

[0182] The recycled product blend of EI2 can comprise from 2 to 15 different grades of polyamide 11 (PA11), provided that the inherent viscosity is 0.95 and the dispersity is 2.5. The compositions according to the invention exhibit improved cold shock properties. EC2 shows that a semi-aromatic polyamide, although exhibiting high dispersity, has poorer shock properties.

Claims

Demands

1. A polyamide composition comprising, by weight: (a) 35 to 100% of a polyamide component comprising, by weight relative to the total weight of the polyamide component: a. 50% to 95% of at least one polyamide A, b. 5 to 50% of at least one polyamide B different from polyamide A, (b) 0 to 65% of fillers, (c) 0 to 30% of at least one impact modifier, (d) 0 to 15% of at least one plasticizer, and (e) 0 to 5% of at least one additive, the sum of constituents (a) to (e) being equal to 100%, wherein the polyamide component (a) of the composition has a dispersity (D) greater than 2.25, in particular greater than 2.35, in particular from 2.5 to 15.

2. Composition of polyamides according to claim 1, wherein the polyamide component (a) comprises at least 50%, advantageously 75%, preferably 95%, in particular 100% aliphatic polyamide.

3. Composition of polyamides according to claim 1 or 2, wherein the polyamide component (a) has a C / N ratio greater than or equal to 6.5, in particular greater than or equal to 7.5, in particular greater than or equal to 8.5, more particularly greater than or equal to 9.

5.

4. Composition of polyamides according to any one of claims 1 to 3, wherein the polyamide component (a) comprises less than 1000 ppm of catalyst and / or polyamides having non-reactive end-chain functions and / or polyamides having an NH2 / COOH end-chain function ratio greater than 1.

5. Composition of polyamides according to any one of claims 1 to 4, wherein the inherent viscosity difference between polyamide A and B is greater than 0.1, in particular greater than 0.2, notably greater than 0.

4.

6. Composition of polyamides according to any one of claims 1 to 5, having an inherent viscosity of less than 1.7, in particular less than 1.5, especially less than 1.

3.

7. Composition of polyamides according to any one of claims 1 to 6, wherein the polyamide component (a) comprises at least 30% recycled polyamide.

8. Composition of polyamides according to claim 7, wherein said recycled polyamide has one or more functions resulting from oxidation reactions selected from the primary amide, nitrile, methyl group at the end of the chain, alkene, formamide, imide, carboxylic acid and alcohol functions, in a molar ratio with respect to the amide functions greater than that of the same polyamide constituting an unused article which has never been used.

9. Composition according to claim 8, wherein the molar ratio of functions resulting from oxidation reactions relative to secondary amide functions is from 0.0001 to 0.

3.

10. Composition according to claim 8 or 9, wherein the molar ratio of imide functions to secondary amide functions is from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.

05.

11. Composition according to any one of claims 8 to 10, wherein the molar ratio of carboxylic acid functions to secondary amide functions is from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.

05.

12. Composition according to any one of claims 8 to 11, wherein the molar ratio of alcohol functions to secondary amide functions is from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.

05.

13. Composition according to any one of claims 8 to 12, wherein the molar ratio of nitrile functions to secondary amide functions is from 0.0005 to 0.02, in particular from 0.001 to 0.08, in particular from 0.005 to 0.

05.

14. Use of a composition according to any one of claims 1 to 13 for the manufacture of an article by injection.

15. A method for preparing a composition according to any one of claims 1 to 13, comprising the step of: (i) mixing the constituents (a) to (e) in the molten state, in particular in an extruder.

16. A preparation method according to claim 15, wherein step (i) is carried out with a residence time of less than five minutes. 23

17. A method for implementing a composition according to any one of claims 1 to 13, comprising an extrusion or injection step of said composition at a temperature below 300 °C, preferably 280 °C.