Footwear element in contact with the ground

Abstract

The invention mainly relates to a footwear sole, in particular an outer sole, made of a composition comprising, by weight relative to the total weight of the composition: (a) 50% to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, wherein the polyether blocks comprise on average at least 50% of polyether blocks, wherein the polyether blocks comprise on average more than 50% of ether units comprising at least 3 carbon atoms per oxygen atom; (b) 0 to 50%, preferably 5% to 40% and in particular 10% to 30% of fillers; and (c) 0 to 5%, preferably 0.1% to 4% and in particular 1% to 3% of additives, wherein the composition has a Shore hardness of less than 100A and a density greater than 0.85, and wherein the PEBA has a number-average molar mass Mn, as measured by size-exclusion chromatography according to the ISO 16014-1: 2019 standard, of between 10 000 and 70 000 g / mol.

Description

[0001] SHOE ELEMENT IN CONTACT WITH THE GROUND

[0002] [Technical field]

[0003] This patent application relates to a shoe sole, and more particularly an outsole of a shoe, intended to be in direct contact with the ground, its manufacturing process as well as its use in the manufacture of shoes and a shoe comprising it.

[0004] [Previous technique]

[0005] Shoes generally include an upper and a sole designed to insulate the foot from the ground, prevent wear and tear, and contribute to stabilization and better anchoring of the foot to the ground.

[0006] The sole can be simple, meaning it's made of a single layer, or complex, with multiple structures. For classic shoes, we distinguish the following components: the first part, which is placed on the last and receives the stitching that joins the sole to the upper; the shank, a piece that reinforces the sole at the arch; the midsole, a piece placed between the first part and the outsole to increase the sole's thickness; the outsole; and the heel. In athletic shoes, we generally distinguish between the outsole, the midsole, and the insole.

[0007] The soles can be made from a variety of materials, the most common today being natural rubber, polyurethane, and PVC. However, these materials are not, or are difficult to, recycle.

[0008] These materials must meet a wide range of requirements. In particular, they are expected to provide significant comfort, and therefore high flexibility, quiet walking, lightness, and high slip resistance. They are also expected to contribute to extending the lifespan of the shoe thanks to their mechanical properties, especially in terms of elongation at break, tear resistance, and abrasion resistance. Particularly for athletic shoes, it is also desirable for the sole to have good responsiveness (elastic rebound). More recently, the requirement that the material be recyclable has been added to these specifications. Finally, these materials are preferably compatible with modern assembly processes such as bonding and overmolding.

[0009] Application WO 2021 / 101970 A1 describes soles manufactured by extruding a composition comprising thermoplastic elastomer foam particles suspended in a polymer, including thermoplastic polyurethane, polyester, or polyamide. The document mentions poly(ether-block-amides) (PEBA) comprising polyamide blocks and ether blocks. Application US 2016 / 0302508 A1 describes a shoe comprising an upper and a sole made of the same thermoplastic polymer selected from TPU, PA, PET, or PBT. PEBA is mentioned among the polyamides. The outsole may have a Shore hardness between 40A and 80A.

[0010] These soles may, however, have insufficient mechanical properties, particularly in terms of slip resistance on smooth and wet surfaces. They may also be uncomfortable to wear, especially on uneven ground, deform in wet conditions, or produce unwanted noise.

[0011] [Summary of the invention]

[0012] The invention therefore aims to provide a shoe sole, in particular an outsole, made of a composition comprising, by weight relative to the total weight of the composition:

[0013] (a) 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs comprising at least 3 carbon atoms per oxygen atom;

[0014] (b) 0 to 50%, preferably 5 to 40% and in particular 10 to 30% of charges; and

[0015] (c) 0 to 5%, preferably 0.1 to 4% and in particular 1 to 3% of additives, wherein the composition has a Shore hardness of less than 100A and a density greater than 0.85, and wherein PEBA has a number-average molar mass Mn as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol.

[0016] Preferably, the composition further comprises (d) 0 to 40%, preferably 5 to 30%, and in particular 10 to 20% by weight of a polymer other than (a). Advantageously, the composition further comprises (e) 0 to 20%, preferably 2 to 15%, and in particular 5 to 10% by weight of rubber.

[0017] Preferably, the PEBA comprises 50 to 90%, in particular 55 to 85% and especially 60 to 80% by weight of polyether blocks. Advantageously, the polyether blocks comprise on average more than 50% by weight of PTMG motifs. Advantageously, the PEBA comprises on average at least 50% by weight of PTMG motifs. Preferably, PEBA comprises polyamide blocks having 9 or more carbon atoms per amide group, in particular selected from PA10, PAH, PA12, PA513, PA514, PA516, PA518, PA536, PA612, PA613, PA614, PA616, PA618, PA636, PA912, PA104, PA109, PA1010, PA1012, PA1013, PA1014, PA1016, PA1018, PA1036, PA129, PA1210, PA1212, PA1213, PA1214, PA1216, PA1218, PA1236, PA12T, and their copolymers. Preferably, PEBA comprises 10 to 50%, in particular 15 to 45% and especially 20 to 40% by weight of polyamide blocks.Advantageously, PEBA has a ratio between the number-average molar mass of polyamide blocks and the number-average molar mass of polyether blocks of 0.1 to 3.0, preferably of 0.2 to 2.0 and in particular of 0.3 to 1.0.

[0018] According to a second aspect, the invention relates to a method for manufacturing such a sole, comprising the steps of:

[0019] (i) Mix in the molten state, by weight relative to the total weight of the composition: a. 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs having at least 3 carbon atoms per oxygen atom; b. 0 to 50% fillers; and c. 0 to 5% additives, the composition having a Shore hardness of less than 100A and a density greater than 0.85, and the PEBA having a number-average molar mass (Mn) as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol; and

[0020] (ii) shape the resulting composition to form a sole.

[0021] Preferably, step (ii) is carried out by injection.

[0022] According to a third aspect, the invention aims at the use of such a sole for the manufacture of a shoe.

[0023] According to a fourth aspect, the invention relates to a shoe, in particular a sports shoe, comprising such a sole. Preferably, these are dress shoes, for example sneakers, sandals, boots or ankle boots; sports shoes, in particular walking, hiking, athletics, running shoes; team sports shoes, in particular indoor sports, for example football, handball, basketball, or volleyball; tennis shoes, table tennis shoes, badminton shoes, skateboard shoes; ski boots or safety shoes.

[0024] According to a fifth aspect, the invention relates to a method for manufacturing such a shoe, comprising the steps of:

[0025] (I) assembly of a sole as described with a shoe upper, in particular by gluing, heat gluing or overmolding.

[0026] According to a sixth and final aspect, the invention relates to a recycling process for such a shoe, comprising the steps of:

[0027] (1) separation of the sole from the shoe, if applicable;

[0028] (2) grinding of the sole to obtain a pulverized material;

[0029] (3) heating the ground material obtained in step (2) until melted to obtain a molten mass; and

[0030] (4) Extrusion of the molten mass obtained in step (3) to obtain granules. [Description of embodiments]

[0031] Definition of terms

[0032] The term "sole" generally refers to the part of the shoe that lies under the foot and is in contact with the ground. More specifically, when the sole has several parts, the term designates the part(s) of the sole that are external, meaning they come into contact with the ground, particularly the outsole and the heel. In the context of athletic shoes, this is called the outsole, which is distinct from the midsole and the insole.

[0033] The term "thermoplastic elastomer" refers to a polymer comprising rigid and flexible blocks, in the form of a block copolymer, in which the rigid blocks, generally semi-crystalline or having a high glass transition temperature, melt or soften as the temperature increases. Above the melting or glass transition temperature of the rigid block domains, the material can be processed using conventional thermoplastic polymer processing techniques. Below the melting temperature of the rigid block domains, the thermoplastic elastomer exhibits elastic properties similar to those of cross-linked elastomers. PEBA (polyethylene deposition modeling alloys) are explicitly excluded from this definition of thermoplastic elastomers.

[0034] The term “PEBA” refers to a sequenced copolymer comprising rigid blocks and flexible blocks, the rigid blocks being polyamide blocks and the flexible blocks being polyether blocks.

[0035] The term "polyamide" or "PA" refers to a homopolyamide or copolyamide, such as those obtained by the polycondensation of suitable monomers, in particular lactam, α,co-aminocarboxylic acid and / or dicarboxylic acid and diamine. The nomenclature used to define polyamides is described in ISO 1874-1:1992 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (Tables 1 and 2).

[0036] The term "alloy" refers to a homogeneous mixture of polymers (macroscopically, i.e., visible to the naked eye). In one embodiment, the different components of the alloy are linked by one or more covalent bonds.

[0037] In what follows, physical quantities are, unless otherwise stated, measured under normal temperature and pressure conditions, specifically at 23°C and atmospheric pressure. It is further specified that the expressions "between... and..." and "from... to..." used in this description should be understood as including each of the mentioned limits. Finally, unless otherwise stated, percentages are expressed as a percentage of the total weight of the composition. A. Sole

[0038] According to a first aspect, the invention relates to a shoe sole, in particular a wear sole or an outsole, made of a composition comprising a specific PEBA and having a particular hardness and density.

[0039] The sole can, in principle, be any shape, provided it is compatible with its main functions of insulating the foot from the outside, preventing wear and tear, and contributing to the stabilization and better anchoring of the foot to the ground. However, it is generally essentially flat and follows the shape of the sole of the human foot.

[0040] The dimensions of the sole will depend on the shoe size. However, the sole generally has a maximum width of between 50 and 150 mm, with a reference range of 70 to 120 mm and particularly 80 to 100 mm, and a maximum length of between 50 and 500 mm, preferably 80 to 400 mm and particularly 100 to 350 mm. The maximum thickness of the sole most often varies between 0.05 and 24 mm, preferably between 0.1 and 10 mm and advantageously between 0.5 and 5 mm. The length of the sole is generally between 9 and 40 cm.

[0041] Preferably, the sole is designed to provide both good grip on the ground and easy water drainage. To this end, the sole may, for example, have grooved and / or protruding sections distributed regularly or irregularly across its surface. In particular, the sole may have grooves and protrusions forming patterns, especially on the face intended to be in contact with the ground. Advantageously, the grooves form one or more continuous channels leading from the center of the sole to its edge, thus allowing water to drain away to the lateral side of the sole. These grooves preferably have a depth of 0.05 to 10 mm, in particular 0.1 to 5 mm, advantageously 0.2 to 3 mm, for a size 42 sole. The width of the grooves is preferably 0.5 to 100 mm, in particular 1 to 80 mm and advantageously 2 to 50 mm, for a size 42 sole.

[0042] Alternatively, the sole may be fitted with one or more studs distributed across its surface. These studs are preferably made of a composition similar to that of the sole, in order to facilitate manufacturing and recycling.

[0043] The contact area between the sole and a rigid floor such as an aluminium plate, measured according to the method described in the publication by Moncalero et al., (International Journal of Industrial Ergonomics, Vol. 61, September 2017, pages 62-70) by applying a nominal force of 400N on the sole, preferably represents at least 40%, in particular 45 to 95%, especially 50 to 90% and advantageously 60 to 85% of the surface of the sole.

[0044] As mentioned above, the sole can consist of one or more pieces, for example, 1 to 5 pieces, preferably 1 to 3 pieces, advantageously 1 or 2 pieces. For example, the sole may have one piece at the front of the foot and another at the heel, these two pieces not necessarily being joined at the ball of the foot. The sole may also be formed from a single piece extending from the toe to the heel.

[0045] According to the invention, the sole is made of a composition comprising, by weight relative to the total weight of the composition:

[0046] (a) 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs comprising at least 3 carbon atoms per oxygen atom;

[0047] (b) 0 to 50%, preferably 5 to 40% and in particular 10 to 30% of charges; and

[0048] (c) 0 to 5%, preferably 0.1 to 4% and in particular 1 to 3% of additives in which the composition has a Shore hardness of less than 100A and a density greater than 0.85, and in which PEBA has a number-average molar mass Mn as measured by size exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol.

[0049] PEBA

[0050] The composition therefore includes as its main component a particular polyether block amide (PEBA).

[0051] PEBAs result from the polycondensation of reactive-end polyamide blocks with reactive-end polyether blocks. Specifically, PEBAs can result from the polycondensation of:

[0052] 1) diamine-ended polyamide blocks with dicarboxyl-ended polyoxyalkylene blocks; or

[0053] 2) polyamide blocks with dicarboxylic ends with polyetherdiols (polyoxyalkylene α,co-dihydroxylated blocks), the products obtained in this case being polyetheresteramides.

[0054] According to the invention, the PEBA in the composition comprises at least 50%, preferably 50 to 90%, in particular 55 to 85% and especially 60 to 80% by weight of polyether blocks.

[0055] Polyether blocks essentially comprise or are made up of alkylene oxide motifs.

[0056] Polyether blocks comprise on average more than 50%, particularly more than 60%, especially more than 70%, more specifically more than 80%, particularly more than 90%, and especially preferably 100% by weight of ether units comprising at least 3, and especially at least 4, carbon atoms per oxygen atom. A PEBA (polyether board) is preferred in which 80 to 100%, preferably 90 to 100%, and advantageously 95 to 100% by weight of polyether blocks comprise at least 3, and especially 4, carbon atoms per oxygen atom. Indeed, a PEBA with such polyether blocks exhibits reduced hydrophilicity and therefore a low affinity for water, reducing water absorption, particularly during use in wet weather, and improving dimensional stability over time.

[0057] These may include PPG (polypropylene glycol) blocks, made up of propylene oxide motifs, PO3G (polytrimethylene glycol) blocks, made up of polytrimethylene glycol ether motifs, and / or PTMG (polytetrahydrofuran) blocks, made up of tetramethylene glycol motifs, with PTMG blocks being preferred.

[0058] PEBAs can include polyether blocks comprising several distinct polyether motifs, these copolyethers being either block or statistical.

[0059] Preferably, PEBA in the composition comprises up to 50%, in particular 10 to 50%, in particular 15 to 45% and in particular 20 to 40% by weight of polyamide blocks.

[0060] Indeed, when the polyamide block content in PEBA is higher, the PEBA does not adapt sufficiently to surface irregularities, and therefore fails to create the necessary grip with the substrate to achieve the required coefficient of friction for slip resistance, particularly on wet surfaces. Such PEBA also results in discomfort during use, especially on uneven ground.

[0061] Polyamide blocks with dicarboxylic acid ends are obtained, for example, by the condensation of polyamide precursors in the presence of a dicarboxylic acid acting as a chain limiter. Polyamide blocks with diamine ends are obtained, for example, by the condensation of polyamide precursors in the presence of a diamine acting as a chain limiter.

[0062] Three types of polyamide blocks can be used to advantage.

[0063] According to a first type, polyamide blocks come from the condensation of a dicarboxylic acid preferably having 4 to 36, in particular 4 to 20, and in particular 6 to 18 carbon atoms, and a diamine preferably having 2 to 20, in particular 6 to 14 carbon atoms.

[0064] Dicarboxylic acids can be, in particular, aliphatic, cycloaliphatic, or aromatic. Examples of dicarboxylic acids include butanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, brassylic acid, thapsic acid, octadecanedicarboxylic acid, 1,4-cyclohexyldicarboxylic acid, terephthalic acid (T), isophthalic acid (I), and dimerized fatty acids. Dimerized fatty acids preferably have a dimer content of at least 98%; preferably, they are hydrogenated. This includes, for example, products marketed under the brand name "PRIPOL" by the company "CRODA", or under the brand name EMPOL by the company BASF, or under the brand name Radiacid by the company OLEON, and polyoxyalkylenes α, co-diacids.

[0065] The diamine can be, in particular, an aliphatic, cycloaliphatic, or aromatic diamine. Examples include tetramethylenediamine, cadaverine, hexamethylenediamine, 1,10-decamethylenediamine, 1,12-dodecamethylenediamine, trimethylhexamethylenediamine, the isomers of bis-(4-aminocyclohexyl)methane (BACM), bis-(3-methyl-4-aminocyclohexyl)methane (BMACM), and 2-2-bis-(3-methyl-4-aminocyclohexyl)-propane (BMACP), p-amino-di-cyclohexylmethane (PACM), isophoronediamine (IPDA), 2,6-bis-(aminomethyl)norbornane (BAMN), and piperazine (Pip).

[0066] The polyamide block of the first type is preferably chosen from PA 412, PA 414, PA 418, PA 513, PA 516, PA 610, PA 612, PA 613, PA 614, PA 618, PA 912, PA 1010, PA 1012, PA 1014 and PA 1018.

[0067] According to a second type, polyamide blocks result from the condensation of one or more α,β-aminocarboxylic acids and / or one or more lactams in the presence of a dicarboxylic acid having 4 to 18 carbon atoms or a diamine.

[0068] Examples of α,co-amino carboxylic acids include aminocaproic, amino-7-heptanoic, amino-10-decanoic, amino-11-undecanoic and amino-12-dodecanoic acids.

[0069] Lactams are preferably chosen from those which preferably have 6 to 12 carbon atoms, in particular caprolactam, oenantholactam and lauryllactam.

[0070] Advantageously, the second type polyamide blocks are chosen from PA 10, PA 11 and PA 12 blocks.

[0071] According to a third type, polyamide blocks result from the condensation of monomers of the first and second type as described above respectively, for example of at least one α,co-aminocarboxylic acid or lactam with at least one diamine and at least one dicarboxylic acid.

[0072] Examples of third-type polyamide blocks include PA 66 / 6 and PA 66 / 610 / 11 / 12. Advantageously, PEBA thus comprises one or more polyamide blocks selected from PA 10, PA 11, PA 12, PA 54, PA 59, PA 510, PA 512, PA 513, PA 514, PA 516, PA 518, PA 536, PA 64, PA 66, PA 69, PA 610, PA 612, PA 613, PA 614, PA 616, PA 618, PA 636, PA 912, PA 104, PA 109, PA 1010, PA 1012, PA 1013, PA 1014, PA 1016, PA 1018, PA 1036, PA 10T, PA 124, PA 129, PA 1210, PA 1212, PA 1213, PA 1214, PA 1216, PA 1218, PA 1236, PA 12T, and their copolymers.

[0073] Polyamide blocks with 7 or more, especially 9 or more carbon atoms per amide group, are particularly preferred. These polyamides can notably be chosen from PA 10, PA 11, PA 12, PA 513, PA 514, PA 516, PA 518, PA 536, PA 612, PA 613, PA 614, PA 616, PA 618, PA 636, PA 912, PA 104, PA 109, PA 1010, PA 1012, PA 1013, PA 1014, PA 1016, PA 1018, PA 1036, PA 129, PA 1210, PA 1212, PA 1213, PA 1214, PA 1216, PA 1218, PA 1236, PA 12T, and their copolymers.

[0074] The particularly preferred PEBAs include polyamide PA 11 blocks and polyether PTMG blocks or polyamide PA 11 blocks and polyether PTMG blocks.

[0075] Particularly preferred are the polyamide blocks of PEBA selected from the PA 11, PA 12, PA 10, PA 1010, and PA 1012 blocks, especially PA 11 and PA 12, and the polyether blocks of PEBA selected from the polyethylene glycol and polytetrahydrofuran blocks. Particularly preferred PEBAs include blocks of PA 11 and PTMG or PA 12 and PTMG. PEBAs can be obtained, in particular, by copolycondensation of polyetherdiol with carboxyl-terminate polyamides. The general two-step method for preparing PEBA copolymers having ester bonds between the PA and PE blocks is described, for example, in document FR 2846332. The general method for preparing PEBA copolymers having amide bonds between the PA and PE blocks is described, for example, in document EP 1482011.Polyether blocks can also be mixed with polyamide precursors and a diacid chain limiter to prepare polyamide block and polyether block polymers with statistically distributed motifs (one-step process).

[0076] In addition to polyamide and polyether blocks, PEBAs may contain other additional blocks. For example, a PEBA may comprise three different types of blocks (a "triblock"). This triblock may, for instance, include a polyamide block, a polyether block, and a polyester block. Alternatively, it may include a polyamide block and two different polyether blocks, for example, a PPG block and a PTMG block. Preferred triblock PEBAs are copolyetheresteramides.

[0077] The number-average molar mass (Mn) of the polyamide blocks in PEBA is preferably 400 to 20,000 g / mol, in particular 500 to 10,000 g / mol. Preferably, the number-average molar mass of the polyamide blocks in PEBA is less than 4,000 g / mol, and in particular less than 3,000 g / mol. In embodiments, the number-average molar mass of polyamide blocks in PEBA is 600 to 700 g / mol, or 700 to 800 g / mol, or 800 to 900 g / mol, or 900 to 1000 g / mol, or 1000 to 1100 g / mol, or 1100 to 1200 g / mol, or 1200 to 1300 g / mol, or 1300 to 1400 g / mol, or 1400 to 1500 g / mol, or 1500 to 1600 g / mol, or 1600 to 1700 g / mol, or 1700 to 1800 g / mol, or 1800 to 1900 g / mol, or 1900 to 2000 g / mol.

[0078] The number-average molar mass (Mn) of the polyether blocks is preferably 100 to 6000 g / mol, in particular 500 to 3000 g / mol. Preferably, the number-average molar mass of the polyether blocks is greater than 900 g / mol. In some embodiments, the number-average molar mass of the polyether blocks is 1000 to 1200 g / mol, or 1200 to 1400 g / mol, or 1400 to 1600 g / mol, or 1600 to 1800 g / mol, or 1800 to 2000 g / mol.

[0079] The average number-average molar mass of the respective blocks can be adjusted by the chain limiter content. It can be calculated according to the following relationship: [Math 1] of. chsto

[0080] In this formula, n monO mother represents the number of moles of monomer, chain limiter represents the number of moles of excess diacid limiter, MW moThe repeating unit mass represents the molar mass of the repeating unit, and the chain mass represents the molar mass of the excess diacid. The number-average molar mass of the polyamide and polyether blocks can be measured before copolymerization of the blocks by gel permeation chromatography (GPC), according to ISO 16014-1:2019.

[0081] Preferably, PEBA has a ratio of the number-average molar mass of polyamide blocks to polyether blocks of 0.1 to 3.0, particularly 0.2 to 2.0, and especially 0.3 to 1.0. This ratio can be calculated by dividing the number-average molar mass of the polyamide blocks by the number-average molar mass of the polyether blocks. Specifically, the mass ratio of polyamide blocks to polyether blocks in PEBA can be 0.2 to 0.5, 0.5 to 0.7, 0.7 to 1.0, 1.0 to 1.5, or 1.5 to 2.0. When this ratio is too high, the material is too rigid, resulting in poor slip resistance on smooth, wet surfaces and discomfort when walking, especially on uneven ground. Conversely, when this ratio is too low, the material is too flexible and therefore no longer sufficiently resists abrasion, reducing the lifespan of the shoe.

[0082] The PEBA in the composition has a number-average molar mass (Mn) as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol, preferably between 20,000 and 70,000 g / mol, advantageously between 30,000 and 70,000 g / mol. In particular, the number-average molar mass (Mn) of PEBA can be from 40,000 to 60,000 g / mol, or from 50,000 to 70,000 g / mol, for example, from 50,000 to 60,000 g / mol.

[0083] The PEBA is preferably a linear PEBA.

[0084] PEBAs are commercially available, and sold in particular by Arkema under the name PEBAX®, by Evonik under the name Vestamid®, by EMS under the name Grilamid® and by Sanyo under the name Pelestat®.

[0085] Other polymers

[0086] Advantageously, the composition may include, in addition to PEBA, other polymers, including one or more other different thermoplastic polymers.

[0087] Thus, according to a preferred embodiment, the composition further comprises (d) 0 to 40%, preferably 5 to 30% and in particular 10 to 20% by weight of one or more thermoplastic polymers different from (a), in particular thermoplastic elastomers.

[0088] The thermoplastic polymer (d) may in particular be selected from polyolefins, including polypropylene (PP) and polyethylene (PE) and functionalized polyolefins, polyamides, polyesters such as polyethylene terephthalate (PET), polylactic acid (PLA) and poly(butylene succinate (PBS), polystyrene, acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA).

[0089] Preferably, the thermoplastic polymer (d) has a Shore hardness of less than 100A, in particular less than 90A and especially less than 80A. Preferably, the thermoplastic polymer (d) is a thermoplastic elastomer. The thermoplastic elastomer may be selected, in particular, from thermoplastic polyurethane (TPU), a styrene copolymer, or a polyester elastomer, with thermoplastic polyurethane (TPU) and styrene copolymer being preferred.

[0090] In thermoplastic elastomer, soft blocks and rigid blocks can be covalently linked by functions chosen from CC bonds, amides, esters, urethanes, or ureas.

[0091] This can include thermoplastic polyurethane (TPU). It generally results from the reaction of at least one polyisocyanate (X) with at least one compound reactive with isocyanate, preferably having two functional groups reactive with isocyanate, more preferably a polyol, and optionally with a chain extender, optionally in the presence of a catalyst. The rigid blocks of TPU can be blocks of motifs derived from polyisocyanates and chain extenders, while the flexible blocks mainly comprise motifs derived from compounds reactive with isocyanate, preferably polyols.

[0092] Polyisocyanate can be aliphatic, cycloaliphatic, araliphatic, and / or aromatic. Preferably, polyisocyanate is a diisocyanate. Advantageously, the polyisocyanate is chosen from the group consisting of tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene-1,4-diisocyanate, 1,5-pentamethylene diisocyanate, 1,4-butylene diisocyanate, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4-bis(isocyanatomethyl)cyclohexane, l,3-bis(isocyanatomethyl)cyclohexane (HXDI), 2,4-paraphenylene diisocyanate (PPDI), 2,4-tetramethylenexylene diisocyanate (TMXDI), 4,4'-, 2,4'- and / or 2,2'-Dicyclohexylmethane diisocyanate (H12 MDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and / or l-methyl-2,6-cyclohexane diisocyanate, 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI),2,4- and / or 2,6-toluene diisocyanate (TDI), diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethane diisocyanate, phenylene diisocyanate, methylene bis(4-cyclohexylisocyanate) (HMDI), and mixtures thereof. Preferably, the polyisocyanate is selected from the group consisting of diphenylmethane diisocyanates (MDI), toluene diisocyanates (TDI), pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), methylene bis(4-cyclohexylisocyanate) (HMDI), and mixtures thereof. Even more preferably, the polyisocyanate is 4,4'-MDI (4,4'-diphenylmethane diisocyanate), 1,6-HDI (1,6-hexamethylene diisocyanate), or a mixture thereof. Advantageously, it does not comprise cycloaliphatic diisocyanate. Preferably, the polyisocyanate is aliphatic.

[0093] The compound(s) reactive with isocyanate preferably have an average functionality between 1.8 and 3, more preferably between 1.8 and 2.6, and even more preferably between 1.8 and 2.2. The average functionality of the compound(s) reactive with isocyanate corresponds to the number of isocyanate-reactive functions in the molecules, calculated theoretically for one molecule from a quantity of compounds. Preferably, the compound reactive with isocyanate has, according to a statistical average, a number of active Zerewitinoff hydrogens within the above ranges.

[0094] Advantageously, the compound that reacts with the isocyanate has at least one reactive group selected from among the hydroxyl group, the amine group, the thiol group, and the carboxylic acid group. Preferably, the compound that reacts with the isocyanate has at least one hydroxyl reactive group, and more preferably several hydroxyl groups. Thus, particularly advantageously, the compound that reacts with the isocyanate comprises or consists of a polyol.

[0095] Preferably, the compound reactive with the isocyanate has a number-average molar mass, as determined by GPC, according to ISO 16014-1:2012, of 500 to 10000 g / mol, in particular of 500 to 8000 g / mol, preferably still of 700 to 6000 g / mol, in particular of 800 to 4000 g / mol.

[0096] Preferably, the polyol is selected from the group consisting of polyester polyols, polyether polyols, polycarbonate diols, polyalkylene diols, and mixtures thereof. More preferably, the polyol is a polyether polyol, a polyester polyol, and / or a polycarbonate diol, such that the flexible blocks of the thermoplastic polyurethane are polyether blocks, polyester blocks, and / or polycarbonate blocks, respectively. Even more preferably, the flexible blocks of the thermoplastic polyurethane are polyether blocks and / or polyester blocks (the polyol being a polyether polyol and / or a polyester polyol).

[0097] Examples of polyester polyols include polycaprolactone polyols and / or copolyesters based on one or more carboxylic acids selected from adipic acid, succinic acid, pentanedioic acid, and / or sebacic acid, and one or more alcohols selected from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and / or polytetrahydrofuran. Preferably, the polyol is not a cycloaliphatic diol.

[0098] More specifically, the copolyester may be based on adipic acid and a mixture of 1,2-ethanediol and 1,4-butanediol, or the copolyester may be based on adipic acid, succinic acid, pentanedioic acid, sebacic acid or mixtures thereof, and polytetrahydrofuran (tetramethylene glycol), or the copolyester may be a mixture of these copolyesters.

[0099] As a polyether polyol, polyetherdiols (i.e., aliphatic α,co-dihydroxylated polyoxyalkylene blocks) are preferably used. Preferably, the polyether polyol is a polyetherdiol based on ethylene oxide, propylene oxide, and / or butylene oxide, a block copolymer based on ethylene oxide and propylene oxide, polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetrahydrofuran, polybutane diol, or a mixture thereof.The polyether polyol is preferably a polytetrahydrofuran (flexible blocks of thermoplastic polyurethane are therefore blocks of polytetrahydrofuran) and / or a polypropylene glycol (flexible blocks of thermoplastic polyurethane are therefore blocks of polypropylene glycol) and / or a polyethylene glycol (flexible blocks of thermoplastic polyurethane are therefore blocks of polyethylene glycol), preferably a polytetrahydrofuran having a number-average molar mass of 500 to 15000 g / mol, preferably of 1000 to 3000 g / mol.

[0100] The polyalkylene diols usable in the invention are preferably butadiene-based. One or more polyols may be used as a reactive compound with the isocyanate.

[0101] In a particularly preferred manner, the flexible blocks of TPU are blocks of polytetrahydrofuran, polypropylene glycol and / or polyethylene glycol.

[0102] Preferably, a chain extender (Y) is used for the preparation of thermoplastic polyurethane, in addition to the isocyanate and the compound reactive with the isocyanate.

[0103] The chain extender can be aliphatic, araliphatic, aromatic and / or cycloaliphatic.

[0104] It advantageously has a number-average molar mass of 50 to 499 g / mol. The number-average molar mass can be determined by GPC, preferably according to ISO 16014-1:2012. The chain extender preferably has two reactive groups with the isocyanate (also called "functional groups").

[0105] You can use a single chain extender or a mixture of at least two chain extenders.

[0106] The chain extender is preferably bifunctional. Examples of chain extenders are diamines and alkanediols having from 2 to 10 carbon atoms. In particular, the chain extender may be selected from the group consisting of 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-dimethanol cyclohexane, neopentyl glycol, hydroquinone bis(beta-hydroxyethyl) ether (HQEE), di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and / or deca-alkylene glycol, their respective oligomers, polypropylene glycol and mixtures thereof.More preferably, the chain extender is selected from the group consisting of 1,2-ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and mixtures thereof, and even more preferably from 1,3-propanediol, 1,4-butanediol, and / or 1,6-hexanediol. Even more preferably, the chain extender is a mixture of 1,4-butanediol and 1,6-hexanediol, more preferably in a molar ratio of 6:1 to 10:1.

[0107] Preferably, the TPU is semi-crystalline. Its melting temperature (Tf) is preferably between 100°C and 230°C, and even more preferably between 120°C and 160°C. The melting temperature can be measured according to ISO 11357-3 Plastics - Differential scanning calorimetry (DSC) Part 3. Advantageously, the TPU can be recycled TPU and / or partially or completely bio-based TPU.

[0108] Advantageously, the rigid polyurethane block is composed of a diisocyanate selected from 4.4'-MDI, HDI or PDI and / or a diol selected from butanediol, propanediol, pentanediol and hexanediol.

[0109] The mass ratio between the rigid polyurethane blocks and the flexible polyol blocks of the TPU is preferably less than or equal to 1.0, in particular less than 0.9, and in particular less than 0.8. According to one embodiment, this mass ratio is from 0.1 to 1.0, preferably from 0.2 to 0.8 and in particular from 0.3 to 0.5.

[0110] According to one embodiment, PEBA forms an alloy with the thermoplastic elastomer.

[0111] Thus, TPU and PEBA can be bonded by one or more covalent bonds, for example, via a urethane group. Up to 10% by weight, and in particular up to 5% by weight, of PEBA can be covalently bonded to the thermoplastic polyurethane, preferably via a urethane group.

[0112] Rubber

[0113] According to one embodiment, the composition further comprises (e) 0 to 20%, preferably 2 to 15% and in particular 5 to 10% by weight of rubber.

[0114] Rubber may in particular be a synthetic rubber selected from the group consisting of bromobutyl rubber, butyl rubber, polyisoprene rubber, polynorbornene rubber, ethylene propylene rubber (EPR), ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), carboxylated nitrile rubber, polychloroprene rubber (neoprene rubber), polysulfide rubber, polyacrylic rubber, silicone rubber, chlorosulfonated polyethylene rubber, polybutadiene rubber, styrene butadiene rubber (SBR), butyl rubbers (isobutylene-isoprene) or one of their mixtures.

[0115] Among these, polyisoprene rubber, ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), polybutadiene rubber, styrene-butadiene rubber (SBR), butyl rubber (isobutylene-isoprene), styrene-butadiene rubber, and their blends are particularly preferred. Butadiene rubber is especially preferred.

[0116] Charges

[0117] According to the invention, the sole composition also comprises 0 to 50% by weight, preferably 5 to 40% by weight, and in particular 10 to 30% by weight of fillers relative to the total weight of the composition. These fillers may include mineral or organic fillers. Mineral fillers include, in particular, metal oxides and carbonates such as silica, calcium carbonate and zinc oxide, aluminum oxides, calcium carbonate and aluminosilicates, as well as carbon black or molybdenum disulfide. Organic fillers include, in particular, PTFE powder and aramid powder. Mineral fillers are preferred.

[0118] These fillers are usually found in powder form but can also be in other forms, including fibers.

[0119] Additives

[0120] According to the invention, the composition also comprises 0 to 5%, preferably 0.1 to 4% and in particular 0.5 to 3% by weight of additives relative to the total weight of the composition.

[0121] The additive(s) may be chosen from among the following: catalysts, antioxidants, thermal stabilizers, UV stabilizers, light stabilizers, lubricants, flame retardants, nucleating agents, crosslinking agents, anti-abrasion agents, chain extenders, pigments and dyes.

[0122] In a preferred embodiment, the composition comprises 0.05 to 0.2% by weight of one or more antioxidant and / or UV-stabilizing agents. In particular, a phenolic agent combined with a phosphite compound may be used for this purpose.

[0123] Composition

[0124] Advantageously, PEBA's composition is homogeneous when examined with the naked eye, forming a non-heterogeneous, i.e., non-porous medium. Nevertheless, the sole may, for reasons of weight reduction or aesthetics, for example, have one or more cutouts.

[0125] According to the invention, the density of the sole composition, as measured according to ISO 1183-1, is greater than 0.85. Preferably, the density is less than 1.5 and in particular it is from 0.9 to 1.2. Advantageously, the composition is not lightened, in particular not foamed.

[0126] Due to its particular constitution, the sole of the invention presents a set of interesting properties.

[0127] Firstly, it has excellent mechanical properties, including high resistance to slipping on smooth and wet surfaces, which greatly improves grip on wet grass, for example.

[0128] The sole also advantageously exhibits high responsiveness (elastic rebound), as evidenced by the measurement of a low damping factor (tangent delta). The tangent delta is measured on a film approximately 250 µm thick obtained by pressing the granules in a mold above their melting temperature under a 2T load. The test is performed using DMA (Dynamic Mechanical Analysis) in tension according to ISO 6721, with a temperature sweep from -100 to 180°C at a rate of 2°C / min, a frequency of 1 Hz, and an amplitude of 20 µm. The tangent delta value then corresponds to the maximum of the resulting curve. The tangent delta value over the measurement range remains below 0.3, advantageously below 0.2.

[0129] The sole also has a Shore hardness, as measured according to ISO 7619-1 after 3s, of less than 100A, preferably 50A to 95A, preferably 60A to 90A and in particular 70A to 85A.

[0130] Finally, it advantageously exhibits an elongation at break as measured according to ISO 527 greater than 400%.

[0131] Furthermore, the sole of the invention provides exceptional comfort during use. Firstly, the material's flexibility, even at low temperatures, makes it more comfortable, particularly on uneven surfaces, and reduces unwanted squeaking noises. The composition is also lighter than rubber and aromatic TPU, thus making the shoe lighter.

[0132] Finally, the predominantly thermoplastic composition of the sole facilitates its manufacture and recycling.

[0133] According to a preferred embodiment, the sole is made of a composition comprising, by weight relative to the total weight of the composition:

[0134] (a) 50 to 100%, preferably 60 to 95%, and in particular 70 to 90% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs comprising at least 3 carbon atoms per oxygen atom;

[0135] (b) 0 to 50%, preferably 5 to 40% and in particular 10 to 30% of charges;

[0136] (c) 0 to 5%, preferably 0.1 to 4% and in particular 1 to 3% of additives;

[0137] (d) 5 to 30% and in particular 10 to 20% by weight of one or more thermoplastic elastomers different from (a); and

[0138] (e) 2 to 15% and in particular 5 to 10% by weight of rubber, wherein the composition has a Shore hardness of less than 100A and a density greater than 0.85, and wherein PEBA has a number-average molar mass Mn as measured by size exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol.

[0139] A. Sole manufacturing process

[0140] According to a second aspect, the invention relates to a method for manufacturing a sole according to the invention, comprising the steps of:

[0141] (i) Mix in the molten state, by weight relative to the total weight of the composition: a. 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, in which the polyether blocks comprise on average more than 50% ether motifs having at least 3 carbon atoms per oxygen atom; b. 0 to 50% fillers; and c. 0 to 5% additives, the composition having a Shore hardness of less than 100A and a density greater than 0.85, and the PEBA having a number-average molar mass Mn as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol; and (ii) Shape the resulting composition to form a sole.

[0142] Step (i) of the process can in particular be carried out by heating under high shear, for example in an extruder, so as to allow good dispersion of the molten components and the obtaining of a homogeneous mixture.

[0143] The sole of the invention can be manufactured by any means known to a person skilled in the art. Preferably, it is manufactured by injection molding. Therefore, step (ii) can advantageously be carried out by injection molding.

[0144] B. Usage

[0145] According to a third aspect, the invention aims at the use of a sole of the invention, in particular an outsole, for the manufacture of a shoe.

[0146] This can include dress shoes, for example sneakers, sandals, boots or ankle boots, or sports shoes, including walking, hiking, athletics, running, team sports, especially indoor sports, for example football, handball, basketball, or volleyball, tennis shoes, table tennis, badminton, skateboarding shoes, ski boots or even professional shoes such as safety shoes.

[0147] The shoe can be manufactured by any means known to a person skilled in the art. Thus, for example, the outsole can be assembled with the midsole and the upper, and then the insole is inserted into the shoe thus formed.

[0148] According to an advantageous embodiment, the upper comprises or is made of polyamide or PEBA. Such an upper and sole assembly is easily recyclable, unlike an assembly with a sole comprising or made of non-recyclable materials such as rubber. C. Footwear

[0149] According to a fourth aspect, the invention relates to a shoe, in particular a sports shoe, comprising a sole as described above.

[0150] Ideally, these are dress shoes, such as sneakers, trainers, sandals, boots, or ankle boots. They can also include sports shoes, particularly for walking, hiking, athletics, running, team sports (especially indoor sports like football, handball, basketball, or volleyball), tennis shoes, table tennis shoes, badminton shoes, skateboarding shoes, ski boots, or safety shoes. Its use in the manufacture of sports shoes, especially running shoes, ski boots, and hiking boots, is particularly targeted.

[0151] In addition to the sole, the shoe generally comprises an upper that surrounds the foot. The upper is advantageously made partially or entirely of thermoplastic polymer, preferably polyamide or PEBA.

[0152] Preferably, the polyamide is a polyamide with at least 7, in particular at least 9 carbon atoms per polyamide motif, and in particular it is PAU or PA12.

[0153] The PEBA intended for the manufacture of the stem preferably comprises, relative to the total polyamide blocks, at least 80 to 100%, in particular 90 to 100% and especially 95 to 100% by weight of polyamide blocks with at least 7, in particular at least 9 carbon atoms per polyamide unit, preferably PAU or PA12 blocks. Furthermore, the PEBA preferably comprises, relative to the total polyether blocks, at least 80 to 100%, in particular 90 to 100% and especially 95 to 100% by weight of polyether blocks with at least 3, in particular at least 4 carbon atoms per ether oxygen, preferably PTMG blocks. A PEBA comprising PA11 and PTMG blocks or PA12 and PTMG blocks is particularly preferred.

[0154] According to one embodiment, the polyamide and / or PEBA may comprise 0 to 60% by weight of additives or fillers, in particular chosen from those described above for the composition of the sole.

[0155] In addition to their good performance and excellent comfort, the shoes of the invention have the advantage of a long lifespan.

[0156] D. Shoe manufacturing process

[0157] The sole thus manufactured can then be assembled with other components such as an upper to form a shoe.

[0158] Also, according to a fifth aspect, the invention relates to a method for manufacturing a shoe as described above, comprising the steps of:

[0159] (I) Assembly of a sole according to the invention with a shoe upper, in particular by stitching, gluing, heat-bonding, or overmolding. In a preferred embodiment, the outsole can be assembled with the midsole without the use of glue. In another embodiment, the outsole is then used as an insert and the midsole is overmolded by injection.

[0160] Advantageously, the midsole is made of a composition comprising 50% to 100%, in particular 60% to 100% and advantageously 70% to 100% by weight of PEBA or aliphatic TPU, preferably PEBA. The PEBA and TPU may be selected from those described above for the sole.

[0161] Preferably, the midsole comprises or is made of the composition in foam form. In this case, it is preferable that the foaming be carried out using a supercritical fluid.

[0162] E. Shoe recycling process

[0163] The shoes thus obtained have, in addition to the advantages mentioned, also the advantage of being easily recyclable.

[0164] Finally, according to a sixth aspect, the invention relates to a recycling process for such a shoe, comprising the steps of:

[0165] (a) Separation of the sole from the upper, if applicable;

[0166] (b) Grinding of the sole to obtain a mulch;

[0167] (c) Heating the ground material obtained in step (a) until melted to obtain a molten mass; and

[0168] (d) Extrusion of the molten mass obtained in step (b) to obtain granules.

[0169] The invention will be explained in more detail in the examples that follow.

[0170] [Examples]

[0171] To evaluate properties of interest for sole manufacturing, the following thermoplastic elastomer compositions were prepared and tested. Number molar masses were determined by size exclusion chromatography according to ISO 16014-1:2019.

[0172] PEBA 1: PAU (600 g / mol) and PTMG (1000 g / mol) block copolymer with 62.5% PTMG, with a number molar mass of 60,000 g / mol.

[0173] PEBA 2: Block copolymer PA12 (850 g / mol) and PTMG (2000 g / mol) with 70.2% PTMG, number molar mass of 61000g / mol.

[0174] PEBA 3: Block copolymer PA12 (600 g / mol) and PTMG (2000 g / mol) with 76.9% PTMG, number molar mass 66,000 g / mol.

[0175] PEBA 4: PAU (6000 g / mol) and PTMG (650 g / mol) block copolymer with 9.8% PTMG, with a number molar mass of 46,000 g / mol. PEBA 5: PA6 (Mn=1500 g / mol) and PEG (1500 g / mol) block copolymer with 50% PEG, number molar mass of 55,000 g / mol.

[0176] PEBA 6: PAU (Mn=1000 g / mol) and PTMG (1000 g / mol) block copolymer with 50% PTMG, number molar mass of 45,000 g / mol.

[0177] PEBA 7: Block copolymer PA12 (850 g / mol) and PTMG (2000 g / mol) with 70.2% PTMG, number molar mass of 5000 g / mol.

[0178] PEBA 8: Block copolymer PA12 (850 g / mol) and PTMG (2000 g / mol) with 70.2% PTMG, number molar mass of 800000g / mol.

[0179] TPU1: Elastollan 1185A thermoplastic aromatic polyether-urethane commercially available from BASF.

[0180] PB: Europrene® NEOCIS BR 60 polybutadiene sold by Eni Versalis.

[0181] Compositions EI3 and E 14 were manufactured by molten-state mixing (compounding) in a twin-screw extruder.

[0182] [Table 1]: Compositions of thermoplastic elastomers for soles (in % by weight)

[0183] For the purpose of evaluating the different compositions, plates of 100mm x 100mm x 100mm and 100mm x 100mm x 2mm, blocks of a diameter of 16mm and a thickness of 6mm, and type IA pull-up dumbbells were prepared by injection using a Battenfeld BA800 CDC press with unpolished molds.

[0184] After drying the granules in a desiccator at 70°C for a minimum of 4 hours, they were injected under the following conditions (for examples EI5, EC1 and EC2):

[0185] Barrel temperature: 220-240°C Nozzle temperature: 240°C

[0186] Mold temperature: 30°C Cycle time: 60 seconds.

[0187] The injection was performed under slightly different conditions for examples Eli to EI4 and EC3 to EC4:

[0188] Sheath temperature: 180-200°C

[0189] Nozzle temperature: 200°C

[0190] Mold temperature: 30°C

[0191] Cycle time 60 seconds.

[0192] Regarding the comparative example EC5, it was manufactured using an ENGEL 160T Victory Injection Machine, with a Trexel Series II type physical blowing agent injection system. The mold used is equipped with coreback technology, which generates foam expansion through the recoil of the mold core. The operating parameters are as follows:

[0193] Sheath temperature: 210-230°C

[0194] Holding time before mold opening: 0.2 s

[0195] Mold temperature: 15°C

[0196] Injection flow rate: 120 cm 3 / s

[0197] Mold opening length: up to 15 mm

[0198] Mold: 15 mm thick plate mold

[0199] Dosing volume adjusted to achieve a density of 0.3 on the finished part

[0200] Gas injection pressure (MPP): 250 bar.

[0201] The blowing agent used is dinitrogen introduced at a rate of 0.7% by mass.

[0202] The composition of example EC4 proved difficult to inject; the resulting incomplete specimens did not allow for the evaluation of elongation at break. The molar mass of PEBA is therefore advantageously suited to ensure the composition has sufficient fluidity to allow the injection of thin parts over a long injection length.

[0203] The test specimens obtained with the other compositions were then evaluated in terms of hardness, density, elongation at break, water absorption, abrasion resistance and slip resistance as explained below.

[0204] (a) Hardness

[0205] Shore A hardness is measured according to ISO 48-4:2008 using a durometer at 23°C. The results are summarized in Table 2 below.

[0206] (b) Density The density of an injected part is measured according to ISO 1183-1 by vertical push in water at 23°C using a Sartorius AC 210P hydrostatic balance equipped with a YDK 01 density kit. The results are summarized in Table 2 below.

[0207] (c) Elongation at break in tension

[0208] The elongation at break was measured by tensile testing according to ISO 527 on IA dumbbell-type specimens at a test speed of 50 mm / min after conditioning the specimens for 14 days at 23°C and in an atmosphere with a relative humidity of 50%. The results are summarized in Table 2 below.

[0209] (d) Water absorption

[0210] The measurement is performed on a 100 x 00 x mm plate according to ISO 62:2008 (<5%) after immersion in water at 23°C until equilibrium is reached. Absorption is expressed as a percentage of the difference in mass before and after exposure to water relative to the initial mass. The results are summarized in Table 2 below.

[0211] (e) Slip resistance

[0212] The dynamic friction coefficient was measured on 100mm x 00mm x 2mm plates according to the SATRA TM144 evaluation method on a wet STM 603AC quarry tile standard coating at 23°C, using SATRA STM 603 measuring equipment. Slip resistance is expressed as a coefficient of friction. The higher this coefficient, the greater the slip resistance. The results are summarized in Table 2 below.

[0213] (f) Abrasion resistance

[0214] The abrasion resistance of the compositions is measured according to DIN ISO 4649:2017 (method B with rotating specimen holder) on injection-molded pads with a diameter of 16 mm and a thickness of 6 mm. Abrasion resistance is expressed as the volume change before and after the test. A composition is considered satisfactory when the volume change is less than 100 mm 3 The results are summarized in Table 2 below.

[0215] [Table 2]: Properties of the thermoplastic elastomer compositions studied

[0216] * Injection impossible

[0217] The results highlight that the compositions of the soles of the invention present an excellent compromise of properties in terms of resistance to slipping and abrasion, combined with good mechanical properties, in particular elongation at break, low water absorption and moderate hardness.

[0218] The sole compositions of the invention thus exhibit better slip resistance compared to compositions comprising PEBA with a low content of polyether blocks containing 3 or more carbon atoms per oxygen atom (comparative example EC1). They exhibit lower water absorption and therefore better dimensional and density stability compared to PEBA with PEG polyether blocks (comparative example EC2). Furthermore, the molar mass is appropriate to ensure good mechanical properties, for example, elongation at break (comparative example EC3), while limiting viscosity to allow the injection of thin parts (comparative example EC4). Finally, the density of the composition is important to ensure good abrasion resistance (comparative example EC5).

[0219] [List of cited documents]

[0220] WO 2021 / 101970 Al

Claims

DEMANDS 1. Shoe sole, in particular outsole, made of a composition comprising, by weight relative to the total weight of the composition: (a) 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs comprising at least 3 carbon atoms per oxygen atom; (b) 0 to 50%, preferably 5 to 40% and in particular 10 to 30% of charges; and (c) 0 to 5%, preferably 0.1 to 4% and in particular 1 to 3% of additives, wherein the composition has a Shore hardness of less than 100A and a density greater than 0.85, and wherein PEBA has a number-average molar mass Mn as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol.

2. Sole according to claim 1, wherein the composition further comprises (d) 0 to 40%, preferably 5 to 30% and in particular 10 to 20% by weight of polymer different from (a).

3. Sole according to claim 1 or 2, wherein the composition further comprises (e) 0 to 20%, preferably 2 to 15% and in particular 5 to 10% by weight of rubber.

4. Sole according to any one of claims 1 to 3, wherein PEBA comprises 50 to 90%, in particular 55 to 85% and especially 60 to 80% by weight of polyether blocks.

5. Sole according to any one of claims 1 to 4, wherein the polyether blocks comprise on average more than 50% by weight of polytetrahydrofuran (PTMG) motifs.

6. Sole according to any one of claims 1 to 5, wherein the PEBA comprises polyamide blocks having 9 or more carbon atoms per amide group, in particular selected from PA10, PAU, PA12, PA513, PA514, PA516, PA518, PA536, PA612, PA613, PA614, PA616, PA618, PA636, PA912, PA104, PA109, PA1010, PA1012, PA1013, PA1014, PA1016, PA1018, PA1036, PA129, PA1210, PA1212, PA1213, PA1214, PA1216, PA1218, PA1236, PA12T, and their copolymers.

7. Sole according to any one of claims 1 to 6, wherein PEBA comprises 10 to 50%, in particular 15 to 45% and especially 20 to 40% by weight of polyamide blocks.

8. Sole according to any one of claims 1 to 7, wherein the PEBA has a ratio between the number-average molar mass of the polyamide blocks and the number-average molar mass of the polyether blocks of 0.1 to 3.0, preferably from 0.2 to 2.0 and in particular from 0.3 to 1.

0.

9. A method for manufacturing a sole according to any one of claims 1 to 8, comprising the steps of: (i) Mix in the molten state, by weight relative to the total weight of the composition: a. 50 to 100% of at least one polyether block amide (PEBA) comprising polyamide blocks and polyether blocks, comprising on average at least 50% polyether blocks, wherein the polyether blocks comprise on average more than 50% ether motifs having at least 3 carbon atoms per oxygen atom; b. 0 to 50% fillers; and c. 0 to 5% additives, wherein the composition has a Shore hardness of less than 100A and a density greater than 0.85, wherein the PEBA has a number-average molar mass (Mn) as measured by size-exclusion chromatography according to ISO 16014-1:2019 of between 10,000 and 70,000 g / mol; and (ii) shape the resulting composition to form a sole.

10. Manufacturing method according to claim 9, wherein step (ii) is carried out by injection.

11. Use of a sole according to any one of claims 1 to 8 for the manufacture of a shoe.

12. Footwear, in particular sports footwear, comprising a sole according to any one of claims 1 to 8.

13. Footwear according to claim 12, characterized in that it is dress footwear, for example sneakers, sandals, boots or ankle boots; sports footwear, in particular walking, hiking, athletic, and running shoes; sports shoes collective, particularly indoor, sports such as football, handball, basketball, or volleyball; tennis shoes, table tennis shoes, badminton shoes, skateboard shoes; ski boots or safety shoes.

14. A method for manufacturing a shoe according to claim 12 or 13, comprising the steps of: (1) Assembly of a sole according to any one of claims 1 to 8 with a shoe upper, in particular by gluing, heat bonding or overmolding.

15. Method for recycling a shoe according to claim 12 or 13, comprising the steps of: (1) separation of the sole from the shoe, if applicable; (2) grinding of the sole to obtain a pulverized material; (3) heating the ground material obtained in step (2) until melted to obtain a molten mass; and (4) extrusion of the molten mass obtained in step (3) to obtain granules.

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