Composition based on a polyamide homopolymer or copolymer and a thermoplastic elastomer

Abstract

The invention relates to an adhesive composition comprising a polymer matrix which comprises 40% to 60% by weight of at least one polyamide 6 homopolymer or copolymer (A) and 40% to 60% by weight of at least one thermoplastic elastomer (B) comprising at least one flexible polyether block and at least one rigid polyamide block, wherein the at least one rigid polyamide block of the at least one thermoplastic elastomer (B) is a polyamide 11 homopolymer or copolymer.

Description

[0001] COMPOSITION BASED ON A HOMOPOLYMER OR COPOLYMER BASED ON A POLYAMIDE AND A THERMOPLASTIC ELASTOMER

[0002] The field of the present invention is that of adhesion compositions enabling the assembly of at least two layers, in particular layers intended for use in a non-pneumatic bandage.

[0003] A non-pneumatic tire typically comprises a base (mounting band), designed, for example, for mounting on a rigid rim; a crown reinforcement (or shear band), which connects to a tread; and a deformable structure, such as spokes, ribs, or dimples, positioned between the base and the crown. Non-pneumatic tires are described, for example, in documents WO 03 / 018332A1 and FR2898077A1.

[0004] In the manufacture of a non-pneumatic tire, for example, the various constituent elements of the tire, in particular the tread, the crown reinforcement, the spokes (or rib or cells) and the mounting strip, are assembled together.

[0005] The assembly of the constituent elements of a non-pneumatic bandage can be carried out by overinjection, by gluing, by riveting or by welding.

[0006] Although riveting allows for the mechanical assembly of the component parts, it has the disadvantage of being difficult to implement industrially, and also increases the weight of the non-pneumatic tire, which is detrimental to the fuel consumption of vehicles equipped with such tires. Furthermore, riveting has the disadvantage of concentrating mechanical stress at the rivets, which can potentially initiate cracking at these points.

[0007] The same applies to welding, which has the disadvantage of being difficult to implement industrially.

[0008] Thus, assemblies made by overinjection or by gluing remain preferred.

[0009] Furthermore, each component of a non-pneumatic tire performs a specific function. The tread, for example, which is designed to make contact with the ground as the tire rolls, must possess very specific properties, including good grip on both dry and wet surfaces, low rolling resistance, and good wear resistance. The shear strip, on the other hand, must be deformable and allow for even pressure distribution across the tire. The spokes are responsible for supporting the vehicle's load. As for the mounting strip, it must ensure a secure attachment of the wheel to the hub and allow for the transfer of driving forces to the vehicle or braking forces to the vehicle. Thus, each of these components comprises very specific materials, generally different from one another, and meeting the aforementioned requirements.

[0010] These differences in composition can lead to a decrease in the adhesion properties between the different constituent elements of the bandage.

[0011] Therefore, it remains important to develop compositions with good adhesion properties towards the adjacent layers to be assembled, especially when the compositions of the adjacent layers are of a different nature.

[0012] Thus, a first object of the invention is a composition comprising a polymer matrix which includes:

[0013] - between 40% and 60% by mass of at least one homopolymer or copolymer (A) of polyamide 6 and

[0014] - between 40% and 60% by mass of at least one thermoplastic elastomer (B) comprising at least one flexible polyether block and at least one rigid polyamide block, wherein the at least one rigid polyamide block of the at least one thermoplastic elastomer (B) is a homopolymer or copolymer of polyamide 11.

[0015] The present invention also relates to a laminate comprising at least a first layer of polymeric composition whose polymer matrix comprises more than 50% by mass of at least one homopolymer or copolymer (C) of polyamide 6 or polyamide 11 disposed in contact with a second layer made up of a composition according to the invention.

[0016] The present invention also relates to an article, in particular a non-pneumatic bandage, comprising a composition according to the invention or a laminate according to the invention.

[0017] I- DEFINITIONS

[0018] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0019] Unless otherwise stated, the rates of units resulting from the insertion of a monomer into a copolymer are expressed as a mole percentage relative to the total monomer units of the copolymer.

[0020] In this document, unless expressly stated otherwise, all percentages (%) shown are percentages (%) by mass.

[0021] The term "polymer matrix" refers to all the thermoplastic polymers and thermoplastic elastomers present in a given composition. Various additives, such as plasticizers (liquids or resins) and fillers, which may be present in a given composition, are not included and do not form part of the polymer matrix of that composition.

[0022] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (that is, excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (that is, including the strict bounds a and b). In this context, when an interval of values ​​is designated by the expression "from a to b," it also and preferentially designates the interval represented by the expression "between a and b."

[0023] The compounds mentioned in the description can be of fossil origin or bio-based. In the latter case, they may be partially or entirely derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of previously used materials; that is, they may be partially or entirely produced through a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, fillers, etc.

[0024] Unless otherwise indicated, all glass transition temperature (Tg) and melting temperature (Tf) values ​​described herein are measured using a known method by Differential Scanning Calorimetry (DSC) according to ASTM D3418 (1999). II- DESCRIPTION OF THE INVENTION

[0025] As previously stated, the present invention relates to a composition comprising a polymer matrix which includes:

[0026] - between 40% and 60% by mass of at least one homopolymer or copolymer (A) of polyamide 6 (PA6) and

[0027] - between 40% and 60% by mass of at least one thermoplastic elastomer (B) comprising at least one flexible polyether-type block and at least one rigid polyamide-type block, in which the at least one rigid polyamide-type block of the at least one thermoplastic elastomer (B) is a homopolymer or copolymer of polyamide 11 (PAI 1).

[0028] The mass percentages of at least one homopolymer or copolymer (A) and at least one thermoplastic elastomer (B) are, of course, as indicated, mass percentages relative to the mass of the elastomer matrix.

[0029] A "homopolymer of a polyamide" is defined as a homopolymer consisting of the monomer units of said polyamide. A "copolymer of a polyamide" is defined as a copolymer comprising units of the monomer units of said polyamide and monomer units other than those of said polyamide.

[0030] The monomer unit (or repeating unit) of a polymer is, in a manner known to those skilled in the art, the smallest constituent unit whose repetition describes the polymer. For example, the monomer unit of PA6 is -[(CH2)s-CONH]- and that of PAI 1 is -[(CH2)IO-CO-NH]-.

[0031] The at least homopolymer or copolymer (A) of PA6 can thus be a homopolymer (A) of PA6, that is to say a PA6 or a mixture of PA6, for example of different molecular masses.

[0032] The at least homopolymer or copolymer (A) of PA6 can also be a copolymer of PA6, that is to say a polymer comprising monomer units of PA6 and monomer units other than those of PA6.

[0033] The at least homopolymer or copolymer (A) of PA6 may also be a mixture of at least one homopolymer (A) of PA6 and at least one copolymer (A) of PA6.

[0034] In the PA6 copolymer (A), the PA6 monomer units advantageously represent 20% to 80% by mass of the copolymer, preferably 30% to 70% by mass. The PA6 copolymer (A) may, for example, be a copolymer comprising at least one PA6 block and at least one block of a polymer other than PA6, for example, but not limited to, a PA66, PAIO, or PA12 block.

[0035] Most advantageously, at least one homopolymer or copolymer (A) of PA6 is a PA6 or a mixture of several PA6s.

[0036] Advantageously, the number-average molecular weight (Mn) of the at least homopolymer or copolymer (A) of PA6 is in the range of 5,000 to 200,000 g / mol, preferably 7,000 to 100,000 g / mol, preferably 10,000 to 30,000 g / mol.

[0037] The number-average molecular weight (Mn) of thermoplastic polymers is determined using a known method, by size-exclusion chromatography (SEC). For example, in the case of polyamides, the sample is first solubilized in 2-hexafluoropropanol with the addition of 0.02 M sodium trifluoroacetate at a concentration of approximately 2 g / L. The equipment used is a WATERS Alliance chromatographic system. The elution solvent is 2-hexafluoropropanol with the addition of 0.02 M sodium trifluoroacetate, the flow rate is 0.5 mL / min, and the system temperature is 35°C. A set of three Phenomenex columns in series, commercially known as "Phenogel" (10 µm x 10⁻³), is used.5 ", "lOpm lO 4 " And

[0038] "10pm 10 3 The injected volume of the polymer sample solution is 100 µL. The detector is a WATERS 2410 differential refractometer, and its associated chromatographic data processing software is the WATERS MILLENIUM system. The calculated average molar masses are relative to a calibration curve established with PMMA standards. The conditions are adaptable by a person skilled in the art.

[0039] Examples of commercially available PA6 homopolymers include "Akulon F223-D" from Envalior NV or the PA6 present in "UDea™ Akulon® K20HG60" from DSM, which is composed of PA6 and reinforced with 60% by mass of glass fiber.

[0040] Examples of commercially available PA6 copolymers include "Ultramid® C3" from BASF, which is a copolymer of PA6 and PA66; "Grilon® TS V0" from EMS-GRIVORY, which is a PA6 / PA66 copolymer with flame retardant; "Vestamid® L1930" from Evonik, which is a copolymer of PA6 and PA12; and "Rilsan® PA6-10" from Arkema, which is a copolymer of PA6 and PAIO.

[0041] In this document, "at least one thermoplastic elastomer (B)" refers to "at least one thermoplastic elastomer (B) comprising at least one flexible polyether-type block and at least one rigid polyamide-type block, the at least one rigid polyamide-type block of the at least one thermoplastic elastomer (B) being a homopolymer or copolymer of P Al 1".

[0042] In general, thermoplastic elastomers (abbreviated "TPE") have a structure intermediate between thermoplastic polymers and elastomers. They are block copolymers, made up of rigid, thermoplastic blocks linked by flexible, elastomer blocks.

[0043] In what follows, references to a polyether-type block preferably refer to an elastomeric block composed of more than 50% by mass (preferably more than 80%, preferably more than 90%, preferably 100%) of a polymer resulting from the polymerization of an ether-type monomer. References to a polyamide-type block preferably refer to a block composed of more than 50% by mass (preferably more than 80%, preferably more than 90%, preferably 100%) of a polymer resulting from the polymerization of a polyamide monomer.

[0044] Preferably, the melting temperature (Tf) of the thermoplastic elastomer (B) is in the range of 120°C to 200°C. Advantageously, the Tf of the thermoplastic elastomer is in the range of 140°C to 195°C, preferably from 160°C to 190°C. It may be noted that the Tf of the thermoplastic elastomer corresponds to the Tf of the thermoplastic blocks of the thermoplastic elastomer.

[0045] The number-average molecular weight (Mn) of the thermoplastic elastomer (B) is preferably between 30,000 and 500,000 g / mol, more preferably between 45,000 and 350,000 g / mol. Even more preferably, the Mn of the thermoplastic elastomer is in the range of 50,000 to 300,000 g / mol, and better still, from 60,000 to 150,000 g / mol.

[0046] The molecular weight (Mn) of thermoplastic elastomers is determined using a known method, by size exclusion chromatography (SEC), in the same way as described above for thermoplastic polymers. Thermoplastic elastomers (B) can be linear. For example, a thermoplastic elastomer is a diblock copolymer: a polyether block / a polyamide block. A thermoplastic elastomer can also be a triblock copolymer: a polyether block / a polyamide block / a polyether block, that is, a central elastomer block and two terminal thermoplastic blocks, one at each end of the elastomer block. Similarly, a multiblock thermoplastic elastomer can be a linear sequence of polyether blocks followed by polyamide blocks.

[0047] The thermoplastic elastomer (B) useful for the purposes of the invention may also be in a star shape with at least three points. For example, the thermoplastic elastomer (B) may then consist of a star-shaped polyether block with at least three points and a thermoplastic polyamide block located at the end of each of the points of the polyether block. The number of points of the central elastomer may vary, for example, from 3 to 12, and preferably from 3 to 6.

[0048] Thermoplastic elastomer (B) can also be in branched or dendrimer form. Thermoplastic elastomer (B) can then consist of a branched polyether or dendrimer block and a polyamide block located at the ends of the branches of the polyether dendrimer block.

[0049] Preferably, the thermoplastic elastomer (B) is in linear and multiblock form.

[0050] The elastomer blocks of the thermoplastic elastomer (B) for the purposes of the invention, can be any polyether type elastomers known to those skilled in the art.

[0051] These polyether type elastomer blocks preferably have a Tg below -20°C, preferably with a Tg in a range from -110°C to -35°C, preferably from -90°C to -40°C.

[0052] The polyether-type elastomer blocks of thermoplastic elastomer (B) may be composed of monomers selected from cyclic alcohols or ethers, preferably aliphatic cyclic alcohols or ethers, such as, for example, ethanol or tetrahydrofuran. Preferably, at least one flexible polyether-type block of thermoplastic elastomer (B) is selected from the group consisting of polytetramethylene glycols (PTMG), polyethylene glycols (PEG), polypropylene ether glycols (PPG), polyhexamethylene ether glycols, polytrimethylene ether glycols (PO3G), poly(3-alkyltetrahydrofurans), and mixtures thereof. Preferably, the thermoplastic telastomer polyether block(s) are chosen from the group consisting of polytetramethylene glycol (PTMG), polyethylene glycol (PEG) and their mixtures.

[0053] Advantageously, the poly ether type elastomer blocks of the thermoplastic elastomer have a total Mn ranging from 25,000 g / mol to 350,000 g / mol, preferably from 35,000 g / mol to 250,000 g / mol so as to give the thermoplastic telastomer good elastomeric properties and sufficient mechanical strength compatible with use in the article according to the invention.

[0054] Thermoplastic blocks (rigid polyamide type blocks) of thermoplastic telastomer (B) are homopolymer or copolymer blocks of PAU.

[0055] The at least homopolymer or copolymer of PAU of Thermoplastic Telatomer (B) can thus be a homopolymer block of PAU.

[0056] The at least homopolymer or copolymer of PAU of Thermoplastic Telatomer (B) can also be a copolymer block of PAI 1.

[0057] Preferably, at least one rigid polyamide block of at least one thermoplastic elastomer (B) is a homopolymer or copolymer comprising 30% to 80% by mass, preferably 50% to 70% by mass, of monomer units of PAU.

[0058] The mass fraction of flexible polyether-type thermoplastic telastomer (B) blocks may be in the range of 1% to 70%, preferably 10% to 65%, preferably 20% to 60%. Furthermore, the mass fraction of rigid polyamide-type thermoplastic telastomer (B) blocks may be in the range of 30% to 99%, preferably 35% to 90%, preferably 40% to 80%.

[0059] Specific thermoplastic elastomers in which the thermoplastic blocks are polyamides are usually denoted TPE-A or TPA (thermoplastic copolyamide) or PEBA (block amide copolyether), and they are particularly preferred for the purposes of the invention. Advantageously, thermoplastic telastomer (B) is chosen from the group consisting of polyether-polyamide block copolymers (PEBA), said polyamide blocks preferably being a homopolymer or copolymer of PAU. According to the invention, the thermoplastic blocks of the thermoplastic elastomer (B) have, in total, an average number molecular mass ("Mn") ranging from 5,000 g / mol to 150,000 g / mol, preferably from 10,000 to 100,000 g / mol, so as to give the thermoplastic elastomer good elastomeric properties and sufficient mechanical strength compatible with use in the article according to the invention.

[0060] As an example of commercially available thermoplastic elastomer (B), we can cite for example the "Pebax® Rnew® 55R53 SP 01" from the company Arkema which is a TPE based on PAI 1.

[0061] In the composition according to the invention, the proportion of homopolymer or copolymer (A) is preferably in the range of 41% to 59% by mass, preferably 45% to 55% by mass, relative to the mass of the polymer matrix, and the proportion of thermoplastic elastomer (B) is in the range of 41% to 59% by mass, preferably 45% to 55% by mass, relative to the mass of the polymer matrix.

[0062] Advantageously, the polymer matrix does not comprise any polymer other than at least one homopolymer or copolymer (A) of PA6 and at least one thermoplastic elastomer (B), or comprises less than 20% by mass, preferably less than 10% by mass, preferably less than 5% by mass. Even more preferably, the polymer matrix does not comprise any polymer other than at least one homopolymer or copolymer (A) of PA6 and at least one thermoplastic elastomer (B), i.e., at least one homopolymer or copolymer (A) of PA6 and at least one thermoplastic elastomer (B) constitute 100% by mass of the polymer matrix.

[0063] The composition according to the invention may comprise compounds other than at least one homopolymer or copolymer (A) of PA6 and at least one thermoplastic elastomer (B). These may be additives, known to those skilled in the art, for use with thermoplastics or thermoplastic elastomers. Examples of additives include plasticizers, fillers, processing aids, pigments, and protective agents such as UV stabilizers, ozone inhibitors, antioxidants, and anti-fatigue agents. Of course, reinforcing elements such as metal or textile cables, inorganic fibers (e.g., glass fibers), etc., which may potentially be embedded in a composition, are not additives and are therefore not part of the composition under consideration.The rate of additives in the composition according to the invention can represent from 0% to 20% by mass, for example from 1% to 10% by mass, relative to the mass of the composition according to the invention.

[0064] Thus, the total proportion of homopolymer or copolymer (A) of PA6 and thermoplastic elastomer (B) in the composition can be from 80% to 100% by mass, for example from 90% to 99% by mass.

[0065] The compositions according to the invention can be manufactured in a manner known to those skilled in the art, for example by mixing the various constituents in a molten state in a suitable mixer or extruder (twin-screw extruders, single-screw extruders, mixers). The compositions can be granulated for subsequent use (simply by remelting) or directly injected into a mold or an extrusion or co-extrusion device.

[0066] The present invention also relates to a laminate comprising at least a first layer of polymeric composition whose polymer matrix comprises more than 50% by mass (preferably more than 80%, preferably more than 90%, preferably 100%) of at least one homopolymer or copolymer (C) of PA6 or PAI 1 disposed in contact with a second layer made up of a composition according to the invention.

[0067] The homopolymer or copolymer (C) of PA6 or PAU can be a homopolymer (C) of PA6 or a homopolymer (C) of P Al 1.

[0068] The homopolymer or copolymer (C) of PA6 or PAU can also be a copolymer (C) of PA6 or PAU, that is to say a polymer comprising monomer units of PA6 or PAI 1 and monomer units other than those of PA6 or PAU.

[0069] The homopolymer or copolymer (C) of PA6 or PAU may also be a mixture of at least one homopolymer (C) of PA6 or PAU and at least one copolymer (C) of PA6 or PAU. Preferably, the at least one homopolymer or copolymer (C) of PA6 or PAI 1 is PA6, PAI 1, or a mixture of several PA6s or a mixture of several PAI 1s.

[0070] The homopolymer or copolymer (C) is a copolymer of PA6 or PAU, the monomer units of PA6 or PA1 advantageously representing from 5% to 95% by mass of the copolymer, for example from 9% to 70% by mass of the copolymer. Advantageously, the Mn of the at least homopolymer or copolymer (C) of PA6 or PAU is in the range of 5,000 to 200,000 g / mol, preferably from 7,000 to 100,000 g / mol, preferably from 10,000 to 30,000 g / mol.

[0071] Advantageously, the polymer matrix of the first layer composition does not comprise any polymer other than at least one homopolymer or copolymer (C) of PA6 or PAI 1, or comprises less than 20% by mass, preferably less than 10% by mass, preferably less than 5% by mass. Even more preferably, the polymer matrix does not comprise any polymer other than at least one homopolymer or copolymer (C) of PA6 or PAU, i.e., at least one homopolymer or copolymer (C) of PA6 or PAU constitutes 100% by mass of the polymer matrix of the first layer composition of the laminate according to the invention.

[0072] The composition of the first layer may include compounds other than at least one homopolymer or copolymer (C) of PA6 or PAU. These may include, in particular, the aforementioned additives for the composition according to the invention.

[0073] The rate of additives in the composition of the first layer can represent from 0% to 20% by mass, for example from 1% to 10% by mass, relative to the mass of the composition according to the invention.

[0074] Therefore, preferably, the total proportion of homopolymer or copolymer (C) of PA6 or PAU in the composition of the first layer can be from 80% to 100% by mass, for example from 90% to 99% by mass.

[0075] The laminate according to the invention may comprise a third layer of polymeric composition whose polymer matrix comprises more than 50% by mass (preferably more than 80%, preferably more than 90%, preferably 100%) of at least one homopolymer or copolymer (D) of PA6 or PAU, the second layer consisting of a composition according to the invention being disposed between and in contact with the first and third layers.

[0076] The homopolymer or copolymer (D) of PA6 or PAU can be a homopolymer (D) of PA6 or a homopolymer (D) of PAU.

[0077] The homopolymer or copolymer (D) of PA6 or PAU may also be a copolymer (D) of PA6 or PAU, that is, a polymer comprising monomer units of PA6 or PAI 1 and monomer units other than those of PA6 or PAU. The homopolymer or copolymer (D) of PA6 or PAU may also be a mixture of at least one homopolymer (D) of PA6 or PAU and at least one copolymer (D) of PA6 or PAU. Preferably, the at least one homopolymer or copolymer (D) of PA6 or PAI 1 is PA6, PAI 1, or a mixture of several PA6s or a mixture of several PAI 1s.

[0078] The homopolymer or copolymer (D) is a copolymer of PA6 or PAU, the monomer units of PA6 or PA1 advantageously represent from 5% to 95% by mass of the copolymer, for example from 9% to 70% by mass of the copolymer.

[0079] Advantageously, the Mn of the at least homopolymer or copolymer (D) of PA6 or PAI 1 is in the range of 5,000 to 200,000 g / mol, preferably 7,000 to 100,000 g / mol, preferably 10,000 to 30,000 g / mol.

[0080] Advantageously, the polymer matrix of the third layer composition does not comprise any polymer other than at least one homopolymer or copolymer (D) of PA6 or PAI 1, or comprises less than 20% by mass, preferably less than 10% by mass, preferably less than 5% by mass. Even more preferably, the polymer matrix does not comprise any polymer other than at least one homopolymer or copolymer (D) of PA6 or PAU; that is, at least one homopolymer or copolymer (D) of PA6 or PAU constitutes 100% by mass of the polymer matrix of the third layer composition of the laminate according to the invention.

[0081] The composition of the third layer may include compounds other than at least one homopolymer or copolymer (D) of PA6 or PAU. These may include, in particular, the aforementioned additives for the composition according to the invention.

[0082] The rate of additives in the composition of the third layer can represent from 0% to 20% by mass, for example from 1% to 10% by mass, relative to the mass of the composition according to the invention.

[0083] Thus, preferably, the total proportion of homopolymer or copolymer (D) of PA6 or PAU in the composition of the third layer can be from 80% to 100% by mass, for example from 90% to 99% by mass.

[0084] Advantageously, the polyamide in homopolymer or copolymer (C) is different from the polyamide in homopolymer or copolymer (D). In other words, when homopolymer or copolymer (C) is a homopolymer or copolymer of PA6, homopolymer or copolymer (D) is a homopolymer or copolymer of PAU. When homopolymer or copolymer (C) is a homopolymer or copolymer of PAU, homopolymer or copolymer (D) is a homopolymer or copolymer of PA6.

[0085] Examples of commercially available PAU homopolymers include "Rilsan® - Polyamide 11" from Arkema.

[0086] Examples of commercially available PAI 1 copolymers include "Rilsan® Clear G850" from Arkema.

[0087] The mass percentages of at least one homopolymer or copolymer (C) and (D) are, of course, as indicated, mass percentages relative to the mass of their respective elastomer matrix.

[0088] The laminate according to the invention can be manufactured in a manner known to a person skilled in the art, for example by overinjection using an injection molding machine or by welding assembly.

[0089] The composition according to the invention and the laminate according to the invention can be used in various articles, in particular when the article requires improved adhesion between two compositions of different nature that constitute it.

[0090] Thus, the present invention also relates to an article comprising at least one composition according to the invention or at least one laminate according to the invention.

[0091] This product has applications in a wide range of fields, including food packaging, electronics, automotive, and medical materials. A specific application in the field of non-pneumatic vehicle tires is described below.

[0092] Thus, the article according to the invention can be a non-pneumatic bandage.

[0093] Preferably, the article is a non-pneumatic tire comprising a tread, an annular band, a plurality of spokes extending transversely and radially within the annular band, and a mounting band for connecting the plurality of spokes to a wheel. The tire comprises cushions made of a composition according to the invention, said cushions being arranged between and in contact with the spokes and the radially inner portion of the annular band and / or between and in contact with the spokes and the radially inner portion of the mounting band. Preferably, the radially inner portion of the annular band and / or the radially inner portion of the mounting band is made of a composition of the first layer of the laminate according to the invention, and the spokes in contact with the cushions are made of a composition of the third layer of the laminate according to the invention.

[0094] III- EXAMPLES

[0095] Adhesion tests were performed to determine the quality of the interface between two materials in contact with each other. For this purpose, the following protocol, based on the ASTM DI 002 (2019) standard, was implemented.

[0096] Various sheets of "Material A" were prepared. Materials MAI and MA3 were prepared by injection molding using a Béwéplast Boy XS injection molding machine in an 80x20x2mm mold. The injection conditions were as follows: material temperature: 280°C, mold temperature during injection: 80°C, injection pressure: 1000 bar. Material MA2 is a strip that was cut to the desired dimensions (80x20x2mm). The Material A materials tested were as follows: MAI: "Akulon® F223-D" from Envalior NV, which is a PA6;

[0097] MA2: “UDea™ Akulon® K20HG60” from the company DSM which is composed of PA6 in which approximately 60% by mass of fiberglass is embedded at least partially;

[0098] MA3: “Rilsan® Clear G850” from the company Arkema which is a copolymer partly based on PAU.

[0099] Various "Material B" blends were prepared by mixing a thermoplastic (TP), a thermoplastic elastomer (TPE), or a blend thereof, using a Krauss Maffei "32D Twin Screw Extruder." The mixing conditions were as follows: rotation speed: 300 rpm, total throughput: 3 kg / h, temperature at the extruder barrel: 220°C. The blend was immediately granulated underwater at the screw outlet using a GALA MAP (Manual Adjustable Pelletizer). The Material Bs tested were as follows:

[0100] MB1: 100% by mass of MAY;

[0101] MB2: mixture of 50% by mass of MAI and 50% by mass of "Arkema Pebax® Rnew® 55R53 SP 01" from the company Arkema which is a TPE whose rigid blocks are in PAI 1;

[0102] MB3: mixture of 30% by mass of MAI and 70% by mass of "Arkema Pebax® Rnew® 55R53 SP 01";

[0103] MB4: 100% by mass of MA3. "Material A+B" test specimens were produced by over-injecting "Material B" into a 20x20 mm area at one end of a "Material A" wafer, which had been previously cleaned with ethanol before being placed in its dedicated cavity in the over-injection mold. The over-injection conditions were as follows: material temperature: 280°C, mold temperature during injection: 80°C, injection pressure: 1000 bar. This resulted in test specimens consisting of two wafers, one of "Material A" and the other of "Material B," both measuring 80x20x2 mm, with a 20x20 mm overlap at the wafer ends.

[0104] Once cooled, the test specimens were placed in a tensile testing machine (Instron 6800 series) by inserting the free ends of the plates into the jaws. The longitudinal force required to break the specimens was measured using the "BlueHill" software associated with Instron tensile testing equipment.

[0105] The adhesion results, expressed in Newtons (N), of different specimens of "Material A" / "Material B" are presented in Table 1 below.

[0106] The higher the adhesion value, the better the adhesion. Since Material B is intended to bond two compositions of Material A of different natures, it is understood that the best Material B will be the one that exhibits the highest minimum adhesion result with respect to two Material A compositions.

[0107] [Table 1] The results presented in Table 1 above show that only the MB2 material according to the invention exhibits results greater than 1000 N with respect to the MAI, MA2 and MA3 materials.

[0108] As expected, the MAI material exhibits stronger adhesion to itself than to other materials (MB2, MB3, MB4). Conversely, and surprisingly, Material MB2 (consisting of a 50% by mass mixture of MAI and 50% by mass of PAI 1-based TPE) adheres better to Material MA3 (consisting of a PAI 1-based copolymer) than Material MB4 (consisting of PAI 1-based TPE) does to Material MA3.

[0109] Similarly, it would have been expected that MA2 (made of PA6) would adhere better to MB1 (made of PA6) than to MB2 (made of a 50% by mass mixture of PA6 and 50% by mass of PAU-based TPE). As previously stated, MA2 is a compound comprising 60% by mass of reinforcing elements (glass fibers) embedded at least partially in a PA6 composition. This implies that some of the glass fibers are exposed on the surface of the MA2 material wafer. Unexpectedly, MB2, according to the invention, exhibits better adhesion to MA2 (and therefore to the glass fibers) than to MB1.

[0110] The various tests carried out by the Applicant showed that this surprising effect is obtained when Material B comprises between 40% and 60% by mass of at least one homopolymer or copolymer based on PA6 and between 40% and 60% by mass of at least one thermoplastic elastomer comprising at least one flexible polyether block and at least one rigid PAU-based block. Beyond these percentages, the aforementioned surprising effect is not observed, as demonstrated by the adhesion tests of material MB3 on materials MAI and MA2.

[0111] The present invention therefore provides very interesting materials for improving the adhesion of two materials of different natures. It finds applications in many fields, for example in that of non-pneumatic bandages.

Claims

Demands 1. Composition comprising a polymer matrix comprising: between 40% and 60% by mass of at least one homopolymer or copolymer (A) of polyamide 6 and between 40% and 60% by mass of at least one thermoplastic elastomer (B) comprising at least one flexible block of the polyether type and at least one rigid block of the polyamide type, wherein the at least one rigid block of the polyamide type of the at least one thermoplastic elastomer (B) is a homopolymer or copolymer of polyamide 11.

2. Composition according to claim 1, wherein the proportion of homopolymer or copolymer (A) is in the range of 41% to 59% by mass, preferably 45% to 55% by mass, relative to the mass of the polymer matrix, and the proportion of thermoplastic elastomer (B) is in the range of 41% to 59% by mass, preferably 45% to 55% by mass, relative to the mass of the polymer matrix.

3. Composition according to any one of the preceding claims, wherein the polymer matrix does not comprise any polymer other than at least one homopolymer or copolymer (A) of PA6 and at least one thermoplastic elastomer (B) or comprises less than 20% by mass, preferably less than 10% by mass, preferably less than 5% by mass.

4. Composition according to any one of the preceding claims, wherein at least one homopolymer or copolymer (A) is a polyamide 6 or a mixture of polyamides 6.

5. Composition according to any one of claims 1 to 3, wherein, in the PA6 copolymer (A), the PA6 monomer units represent from 20% to 80% by mass of the copolymer, preferably from 30% to 70% by mass of the copolymer.

6. Composition according to any one of the preceding claims, wherein at least one rigid polyamide-type block of at least one thermoplastic elastomer (B) is a homopolymer or copolymer comprising from 30% to 80% by mass, preferably from 50% to 70% by mass, of polyamide monomer units 7. Composition according to any one of the preceding claims, wherein at least one flexible polyether block of the thermoplastic elastomer (B) is selected from the group consisting of polytetramethylene glycol (PTMG), polyethylene glycols (PEG), polypropylene ether glycol (PPG), polyhexamethylene ether glycol, polytrimethylene ether glycol (PO3G), poly(3-alkyltetrahydrofurans), and mixtures thereof, preferably from the group consisting of polytetramethylene glycol (PTMG), polyethylene glycols (PEG) and mixtures thereof.

8. Composition according to any one of the preceding claims, wherein the mass fraction of flexible poly ether-type block of at least one thermoplastic elastomer (B) is in the range of 1% to 70%, preferably 10% to 65%, preferably 20% to 60%, and the mass fraction of rigid polyamide-type block of at least one thermoplastic elastomer (B) is in the range of 30% to 99%, preferably 35% to 90%, preferably 40% to 80%.

9. Composition according to any one of the preceding claims, wherein at least one thermoplastic elastomer (B) is selected from the group consisting of polyether and polyamide block copolymers.

10. Laminate comprising at least a first layer of polymeric composition whose polymer matrix comprises more than 50% by mass of at least one homopolymer or copolymer (C) of polyamide 6 or polyamide 11 disposed in contact with a second layer made up of a composition according to any one of claims 1 to 8.

11. Laminated according to claim 10, wherein at least one homopolymer or copolymer (C) is a polyamide 6, a polyamide 11 or a mixture of several polyamides 6 or a mixture of several polyamides 11.

12. Laminated according to claim 10 or 11, comprising a third layer of polymeric composition having a polymer matrix comprising more than 50% by mass of at least one homopolymer or copolymer (D) of polyamide 6 or polyamide 11, the second layer consisting of a composition according to the invention being disposed between and in contact with the first and third layers.

13. Laminate according to claim 12, wherein at least one homopolymer or copolymer (D) is a polyamide 6, a polyamide 11 or a mixture of several polyamides 6 or a mixture of several polyamides 11.

14. Laminated according to claim 12 or 13, wherein the polyamide of the homopolymer or copolymer (C) is different from the polyamide of the homopolymer or copolymer (D).

15. Article comprising a composition according to any one of claims 1 to 9 or a laminate according to any one of claims 10 to 14, the article being a non-pneumatic tire comprising a tread, an annular band, a plurality of spokes extending transversely and radially within the annular band, a mounting band for connecting the plurality of spokes with a wheel, characterized in that the tire comprises cushions made of a composition according to any one of claims 1 to 9, said cushions being arranged between and in contact with the spokes and the radially inner part of the annular band and / or between and in contact with the spokes and the radially inner part of the mounting band.

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