Branched polyamide for the production of a foam

Abstract

The invention relates to a specific branched polyamide that can be used to produce an article, in particular a foamed article. The invention also relates to a foam made from said branched polyamide and to the methods for preparing same.

Description

[0001] DESCRIPTION

[0002] Title: Polyamide for the manufacture of foam

[0003] Scope of the invention

[0004] The present invention relates to a particular branched polyamide (also called "branched polyamide"), which can be used for the manufacture of an article, in particular a foamed article.

[0005] The invention also relates to a foam made from said branched polyamide and its preparation processes.

[0006] Technical background

[0007] Polymer foams are used in sporting goods such as sports shoe soles and surfboards, particularly to reduce the weight of the items to provide comfort to users.

[0008] To obtain a low-density foam with good mechanical properties, it is preferable to have a maximum number of closed cells in the foam's cellular structure. During the foaming process, in the cell enlargement stage, the polymer to be foamed undergoes significant elongation between cells. Melt strength (strain hardening) is necessary to prevent the cell walls from breaking down and thus avoid the formation of open cells. By preventing cell wall rupture, the gas used for foam expansion can be retained within the cells, thereby enabling the achievement of low foam densities.

[0009] It is known that one way to obtain strength in the melt state is by introducing branches into the polymer chains.

[0010] However, the solution proposed today involves branching via a compounding process in which a chain extender is used to react with the amine or carboxylic acid chain ends of polyamides. Reference can be made to EP 3688079, which uses a chain extender comprising an epoxy chain extender and a polypropylene wax grafted with maleic anhydride. However, when a chain extender is used to branch polyamides, the molten viscosity becomes very high, making it difficult to process. In such cases, the reaction medium must be heated further, which carries a risk of degradation. There is a continuous need to offer foams with increasingly lower densities while maintaining satisfactory mechanical properties, such as high compressive strength, in order to meet the ever-increasing demands of users.

[0011] The present invention therefore aims to provide a particular branched polyamide, enabling the preparation of low density foams and providing a preparation process that is easier to implement, in particular by avoiding the creation of excessively high molar masses during preparation, and thus avoiding difficulties in transforming the molten polymer.

[0012] Summary of the invention

[0013] According to a first aspect, the invention relates to a branched polyamide, suitable for the preparation of a foam, in which the polyamide comprises branching points provided by a motif from a monomer T comprising x function(s) A and y function(s) B,

[0014] A being a carboxylic acid function,

[0015] B being an amine function, x representing the number of A functions, y representing the number of B functions, x and y being integers greater than or equal to 0 and x+y >=3, the branched polyamide having a weight average molar mass (Mw) greater than or equal to 60,000 g / mol, and the ratio of the z average molar mass (Mz) to the weight average molar mass (Mw) is greater than 1.80.

[0016] According to one embodiment, the average weight molar mass (Mw) of the branched polyamide is from 60,000 to 300,000 g / mol, preferably from 60,000 to 250,000 g / mol.

[0017] According to one embodiment, the ratio of the average molar mass in z (Mz) to the average molar mass by weight (Mw) of the branched polyamide (“Iz”) is greater than or equal to 1.80, for example greater than or equal to 1.90, preferably greater than or equal to 2.00, for example greater than or equal to 2.10.

[0018] According to one embodiment, the ratio of the average molar mass in z (Mz) to the average molar mass by weight (Mw) of the branched polyamide (“Iz”) is less than 8, for example less than 5. According to another embodiment, the ratio of the average molar mass by weight (Mw) of the polyamide to the average molar mass by number (Mn) of the polyamide (“Ip”) is greater than 2.20, for example greater than or equal to 2.30, preferably greater than or equal to 2.40, for example greater than or equal to 2.50, even more preferably greater than or equal to 2.60, for example greater than or equal to 2.80.

[0019] According to one embodiment, the ratio of the average molar mass by weight (Mw) of the polyamide to the average molar mass by number (Mn) of the polyamide (“Ip”) is less than 13, for example less than 8.

[0020] It has been observed in the context of the present invention that branched polyamide, as defined above, makes it possible to increase the closed cell ratio of a foam prepared from branched polyamide and / or to guarantee a low density of the foam, or even a decrease in the density of the foam.

[0021] The polyamide that may be used in the context of the invention may in particular be chosen from a homopolyamide PA 11, PA12, PA 610, PA 612, PA 614, PA 618, PA 910, PA 912, PA 106, PA 1010, PA 1011 PA 1012, PA 1014, PA 1018, and / or PA1036 or a copolyamide of these.

[0022] According to one embodiment, x the number of function A or y the number of function B of monomer T is an integer greater than or equal to 0, preferably x or y is an integer equal to 0.

[0023] For example, monomer T may include 3 A functions and 0 B functions, or 0 A functions and 3 B functions, or 1 A function and 2 B functions, or 2 A functions and 1 B function.

[0024] According to one embodiment, the monomer T is chosen from a polyacid, a polyamine and a compound containing at least one amine function and at least one carboxylic acid function.

[0025] In one embodiment, monomer T is present in the branched polyamide in an amount greater than 0.05%, preferably greater than 0.1%, or 0.15%, or 0.2%, or 0.25%, or 0.3%, or 0.35%, or 0.4%, or 0.45%, or 0.5%, and less than 3%, preferably less than 2.5%, or 2%, or 1.5%, or 1%, relative to the total number of moles of monomer T and the monomers of the polyamide. In another embodiment, monomer T is present in the branched polyamide in an amount of 0.05 to 3% by mole, preferably 0.1 to 2%, more preferably 0.2 to 1% by mole, relative to the total number of moles of monomer T and the monomers of the polyamide.

[0026] According to one embodiment, the branched polymer may comprise two or more different T monomers.

[0027] According to one embodiment, branched polyamide has a difference in absolute value between its total acidity and its total basicity of less than 0.070 mEq / g.

[0028] According to one embodiment, the branched polyamide as defined above comprising motifs from a bifunctional co-monomer selected from a diamine or a diacid, which may be selected from a dicarboxylic acid, in particular those having 4 to 36 carbon atoms, or a diamine, preferably an aliphatic, cycloaliphatic or aromatic diamine, in particular those having 2 to 20 carbon atoms.

[0029] According to one embodiment, a bifunctional co-monomer, preferably a diamine or a diacid, is present in the branched polyamide with monomer T, preferably in an amount that allows a polyamide to have an absolute difference between its total acidity and its total basicity of less than 0.070 mEq / g.

[0030] According to one embodiment, the branched polyamide contains more than 0.05%, preferably more than 0.5%, or 0.9%, or 1%, or 1.5% and less than 5%, preferably less than 3%, or 2.5%, or 2%, of all monomer(s) T and where applicable co-monomer(s) described above, relative to the total number of moles of monomer(s) T, where applicable co-monomer(s) and monomer(s) of the polyamide.

[0031] In one embodiment, the branched polyamide contains from 0.05 to 5%, preferably from 0.5 to 3%, and even more preferably from 0.5 to 2.5%, preferably from 0.5 to 2%, and even more preferably from 1 to 2% by mole, of all the monomer(s) T and, where applicable, co-monomer(s) described above, relative to the total number of moles of monomer(s) T, where applicable, co-monomer(s), and monomers of the polyamide. In one embodiment, the branched polyamide has a melt strength coefficient (strain hardening resistance) greater than 1.0, preferably greater than 1.3.

[0032] According to one embodiment, the branched polyamide has a melt strength coefficient (resistant to "strain hardening") greater than 2.0, preferably greater than 3.0.

[0033] The present invention also relates to a process for preparing a branched polyamide as defined above, comprising at least one step of mixing the monomer T with monomers of a polyamide and a step of synthesizing the branched polyamide by polycondensation, preferably, the monomer T being mixed in an amount of 0.05 to 3% by mole, preferably 0.1 to 2%, more preferably 0.2 to 1% by mole, relative to the total number of moles of monomer T and the monomers of the polyamide.

[0034] According to one embodiment, a bifunctional co-monomer, preferably a diamine or a diacid, is mixed together with the monomer T, with the polyamide monomers, preferably, in an amount enabling the polyamide to have an absolute difference between its total acidity and its total basicity of less than 0.070 mEq / g.

[0035] According to one aspect, the invention relates to a composition comprising branched polyamide as described above and one or more additive polymers, one or more additives, fillers and / or reinforcing fibers.

[0036] The present invention provides a branched polyamide and a composition containing said branched polyamide having improved foamability and enabling the formation of a foam having a high closed cell ratio and / or exhibiting a very low density.

[0037] According to another aspect, the invention relates to an article made of branched polyamide as defined above or made of a composition comprising branched polyamide as defined above.

[0038] The article may advantageously be a foam. Thus, the present invention also relates to a foam made of a branched polyamide as defined above or made of a composition comprising a branched polyamide as described above.

[0039] According to one embodiment, the foam has a density less than or equal to 800 kg / m³ 3 , preferably less than or equal to 600 kg / m 3 , more preferably less than or equal to 400 kg / m 3 , even more preferably less than or equal to 300 kg / m 3 , preferably less than or equal to 150 kg / m 3 .

[0040] The article, preferably foam, as described above may be chosen from sports shoe soles, balls or balloons, gloves, surfboards, personal protective equipment, rail soles, automotive parts, construction parts and electrical and electronic equipment parts.

[0041] According to another aspect, the present invention relates to a method for manufacturing a foam as defined above, comprising the following steps:

[0042] - the mixture of branched polyamide, possibly with one or more additives, and with a blowing agent; and

[0043] - the foaming of the mixture of branched polyamide, possibly with one or more additives and expanding agent.

[0044] The invention is now described in detail and in a non-limiting manner in the following description.

[0045] Description of the invention

[0046] Definition

[0047] In this description, it is specified that when reference is made to intervals, expressions of the type "between... and..." or "from... to..." include the bounds of the interval.

[0048] Unless otherwise stated, percentages are expressed as mass percentages. Unless otherwise stated, the parameters referred to are measured at atmospheric pressure and ambient temperature (23°C).

[0049] The "weight average molar mass (Mw)", the "number average molar mass (Mn)" and the "Z average molar mass (Mz)" in the present invention are expressed in PMMA equivalents (used as a calibration standard) and are measured by size exclusion chromatography (SEC) according to ISO 16014-1:2012, the copolymer being solubilized in hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate for 24 h at room temperature at a concentration of 1 g / L before being passed through the columns, for example at a flow rate of 1 mL / min, the molar mass being measured by the refractive index.

[0050] Size exclusion chromatography can be carried out using modified silica columns, for example on a set of two columns and a pre-column of modified silica (such as the PGF columns and pre-columns from Polymer Standards Service) comprising a 1000 Å column, dimensions 300 x 8 mm and particle size 7 pm, a 100 Å column, dimensions 300 x 8 mm and particle size 7 pm and a pre-column dimensions 50 x 8 mm, for example at a temperature of 40°C.

[0051] The "total acidity" of the polyamide in the present invention is measured according to the following method: 1 g of polyamide is dissolved in 80 mL of hot 2-tert-butylphenol. The sample is then cooled. It is then titrated potentiometrically using a Metrohm titrator (888 or 716) with a combined pH electrode, with a 0.02 N tetrabutylammonium hydroxide solution. The potential-volume curve shows a jump at an equivalent volume from which the total acidity is calculated using the following formula:

[0052] [Math 1]

[0053] Veq X [TB AO H] Total acidity (mEq / o') = - m in which Veq designates the equivalent volume obtained by potentiometric titration, [TBAOH] designates the concentration of the tetrabutylammonium hydroxide solution, i.e. 0.02 N, m designates the mass of the sample, i.e. 1g.

[0054] The "total basicity" of the polyamide in the present invention is measured according to the following method. 1 g of polyamide is dissolved in 80 mL of hot metacresol. The sample is then cooled. It is then titrated potentiometrically using a Metrohm titrator (888 or 716) with a combined pH electrode, with a 0.02 N perchloric acid solution in acetic acid. The potential-volume curve shows a jump at an equivalent volume from which the total basicity is calculated using the following formula:

[0055] [Math 2]

[0056] Veq X [HCIO4]

[0057] Total basicity (mEq / o') = - m in which Veq designates the equivalent volume obtained by potentiometric titration, [HCIO4] designates the concentration of the perchloric acid solution, i.e. 0.02 N, m designates the mass of the sample, i.e. 1g.

[0058] The "melting temperature (Tf)" in the present invention is measured by Differential scanning calorimetry (DSC) according to ISO 11357-3:2018. The melting temperature corresponds to the maximum intensity of the signal of the melting peak in the first heating with a temperature ramp of 20°C / min.

[0059] The "melting end temperature" corresponds to the temperature after the melting peak, where the melting curve measured by DSC and the baseline overlap. The baseline designates the portion of the recorded thermogram without any transitions, specifically in this case, without any first-order transitions such as melting or crystallization. At a transition zone, a virtual baseline can be determined: this is an imaginary line drawn across the transition zone, assuming that the heat due to the transition is zero.

[0060] The "molten strength coefficient", also called the "strain hardening coefficient", is calculated from rheology measurements: a first measurement of the oscillating viscosity as a function of time is carried out at the melting end temperature on an ARES G2 equipped with parallel plane geometry of 25mm diameter, rotation speed 0.01 s-1, under nitrogen sweep.

[0061] A second measurement of extensional viscosity as a function of time is performed at the melting point on ARES G2 equipped with the EVF (Extensional Viscosity Fixture) module, rotation speed 1 s -1 under nitrogen scanning on samples 750pm thick and 10mm long.

[0062] The coefficient of resistance in the molten state is calculated using the following formula:

[0063] [Math 3] Molten strength coefficient where max ( / i ei) is the maximum value of the elongational viscosity curve as a function of time and [i osc is the value of the oscillating viscosity measured at the same time as the max value ( / i ei ).

[0064] Monomer T

[0065] The monomer T used to create the branch points in the polyamide comprises x function(s) A and y function(s) B, A being a carboxylic acid function,

[0066] Given that B is an amine function, x represents the number of functions A, y represents the number of functions B, x and y are integers greater than or equal to 0 and x+y >=3,

[0067] According to one embodiment, the monomer T is chosen from a compound containing at least one amine function and at least one carboxylic acid function, polyacids, polyamines, for example triacids, triamines.

[0068] For example, monomer T can be a compound containing one amine function and two carboxylic acid groups, or a compound containing two amine groups and one carboxylic acid function.

[0069] Examples of polyacids include trimesic acid, [2,2',6',2"- Terpyridine]-4,4',4"-tricarboxylic acid, 1,2-Diaminopropane-N,N,N',N'-tetraacetic acid, Biphenyl-3,3',5,5'-tetracarboxylic acid, and fatty acid trimers; among polyamines, melamines, tri(aminoalkyl)amines, tris(2-aminoethyl)amine, polyalkylenetriamine, dialkylenetriamine, diethylenetriamine, polyethertriamine (for example marketed under the name Jeffamine®T403) among compounds containing at least one amine function and at least one carboxylic acid function, α, co-amino acids (for example, aspartic acid, lysine, glutamic acid) and / or aniline dicarboxylate (for example, 2-aminoterephthalic acid, 5-aminoisophthalic acid etc)

[0070] trendy polyamide

[0071] Typically, branched polyamide has a weight average molar mass (Mw) greater than or equal to 60,000 g / mol, preferably greater than or equal to 65,000 g / mol, even more preferably greater than or equal to 70,000 g / mol, preferably even greater than or equal to 80,000 g / mol.

[0072] According to one embodiment, the average weight molar mass (Mw) of branched polyamide is from 60,000 to 300,000 g / mol.

[0073] In one embodiment, the weight-average molar mass (Mw) of the branched polyamide is from 70,000 to 250,000 g / mol, preferably from 80,000 to 200,000 g / mol, and more preferably from 80,000 to 150,000 g / mol. In another embodiment, the branched polyamide has a weight-average molar mass (Mz) greater than or equal to 110,000 g / mol, preferably greater than or equal to 120,000 g / mol, and even more preferably greater than or equal to 150,000 g / mol.

[0074] According to one embodiment, the average Z-molar mass (Mz) of branched polyamide is from 110,000 to 500,000 g / mol.

[0075] According to one embodiment, the average Z-molar mass (Mz) of the branched polyamide is 120,000 to 250,000 g / mol, preferably 150,000 to 250,000 g / mol.

[0076] The polyamide on which the branching is obtained can be a homopolyamide or a copolyamide or a mixture of these.

[0077] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", particularly on page 3 (tables 1 and 2) and is well known to those skilled in the art.

[0078] Homopolyamide in the sense of the invention means the polymerization products of aminocarboxylic acid monomers, lactams or diacids with diamines.

[0079] According to a first type, polyamides are derived from the condensation of a dicarboxylic acid, in particular those having 4 to 36 carbon atoms, preferably those having 4 to 20 carbon atoms, more preferably 6 to 18 carbon atoms, and an aliphatic, cycloaliphatic or aromatic diamine, in particular those having 2 to 20 carbon atoms, preferably those having 6 to 14 carbon atoms, possibly in the presence of a chain limiter.

[0080] Examples of dicarboxylic acids include 1,4-cyclohexyldicarboxylic acid, butanedioic, adipic, azelaic, suberic, sebacic, dodecanedicarboxylic, octadecanedicarboxylic acids and terephthalic and isophthalic acids, as well as dimerized fatty acids.

[0081] Examples of diamines include tetramethylenediamine, hexamethylenediamine, 1,10-decamethylenediamine, dodecamethylenediamine, trimethylhexamethylenediamine, isomers of bis-(4-aminocyclohexyl)methane (BACM), bis-(3-methyl-4-aminocyclohexyl)methane (BMACM), and 2-2-bis-(3-methyl-4-aminocyclohexyl)propane (BMACP), para-amino-di-cyclohexylmethane (PACM), isophoronediamine (IPDA), 2,6-bis-(aminomethyl)norbornane (BAMN) and piperazine (Pip).

[0082] Advantageously, polyamides PA 412, PA 414, PA 418, PA 610, PA 612, PA 614, PA 618, PA 910, PA 912, PA 106, PA 1010, PA 1011, PA 1012, PA 1014, PA 1018, and / or PA1036 are used.

[0083] In the notation "PA XY", X represents the number of carbon atoms from diamine, and Y represents the number of carbon atoms from diacid, in a conventional way.

[0084] According to a second type, polyamides result from the condensation of one or more α,co-aminocarboxylic acids and / or one or more lactams having 6 to 12 carbon atoms, possibly in the presence of a chain limiter.

[0085] Examples of lactams include caprolactam, oenantholactam and lauryllactam.

[0086] Examples of α,co-amino carboxylic acids include aminocaproic, 7-aminoheptanoic, 10-aminodecanoic, 11-aminoundecanoic and 12-aminododecanoic acids.

[0087] Advantageously, the second type polyamides are PA 10 (polydecanamide), PA 11 (polyundecanamide), PA 12 (polydodecanamide) or PA 6 (polycaprolactam).

[0088] In the notation "PA Z", Z represents the number of carbon atoms derived from amino acid or lactam.

[0089] According to a third type, polyamides result from the condensation of at least one α,co-aminocarboxylic acid (or a lactam), at least one diamine and at least one dicarboxylic acid.

[0090] In this case, polyamide PA is prepared by polycondensation: of linear or cycloaliphatic or aromatic aliphatic diamine(s) having X carbon atoms, X being between 2 and 20;

[0091] - of the dicarboxylic acid(s) having Y carbon atoms, Y being between 4 and 36; and

[0092] - of the comonomer(s) {Z}, chosen from lactams and o,co-aminocarboxylic acids having Z carbon atoms, Z being between 6 and 12 and equimolar mixtures of at least one diamine having X1 carbon atoms and at least one dicarboxylic acid having Y1 carbon atoms, X1 being between 2 and 20, Y1 being between 4 and 36 and (X1 , Y1 ) being different from (X, Y), in the possible presence of a chain limiter.

[0093] According to a variant of this third type, polyamides result from the condensation of at least two α,co-aminocarboxylic acids or at least two lactams having 6 to 12 carbon atoms or of a lactam and an aminocarboxylic acid not having the same number of carbon atoms in the possible presence of a chain limiter.

[0094] Examples of third-type polyamide blocks include: PA 11 / 12, PA 10 / 11 / 12.

[0095] The notations "PA X / Y, PA X / Y / Z", etc. refer to copolyamides in which X, Y, Z, etc. represent homopolyamide units as described above.

[0096] Typically, a chain limiter comprises at least one, preferably at least two, functional groups, each independently selected from carboxylic acids and amines. The chain limiter can be a monocarboxylic acid, a dicarboxylic acid, a monoamine, or a diamine. It allows reaction with the amine or carboxylic acid groups of the polyamide.

[0097] Preferably, the polyamide is an aliphatic polyamide.

[0098] Typically, the average molar mass by weight (Mw) as well as the Mz / Mw ratio can be modulated, notably by varying the type of monomer T used and adjusting its quantity.

[0099] Thus, by combining and adjusting these different parameters, a person skilled in the art is able to synthesize branched polyamides meeting the characteristics defined in the claim.

[0100] Composition

[0101] • Additional polymers

[0102] The composition according to one aspect of the invention may include one or more additional polymers, for example, unbranched polyamides, thermoplastic elastomers (for example, TPU, PEBA, COPE), functional polyolefins, ethylene and vinyl acetate copolymers (for example, products marketed under the Evatane brand by SK functional polymer), or ethylene and acrylate copolymers, or ethylene and alkyl(meth)acrylate copolymers (for example, products marketed under the Lotryl brand by SK functional polymer).

[0103] These additional polymers can be used to adjust the hardness of the branched polyamide. They can be present in a content of 0 to 30% by weight, preferably 5 to 30% by weight, relative to the total weight of the branched polyamide in the composition.

[0104] • Additives, Fillers and Fibers

[0105] The composition according to one aspect of the invention may also include one or more additives, such as one or more flame retardants, one or more flame retardant synergists, one or more metal oxides, a catalyst, one or more antioxidants, one or more thermal stabilizers, one or more UV stabilizers, one or more light stabilizers, one or more lubricants, one or more fillers, one or more plasticizers, one or more nucleating agents, one or more colorants, one or more electrically conductive agents, one or more thermally conductive agents, or a mixture thereof.

[0106] The fillers that may be used include mineral fillers, such as those chosen from the group, given as a non-limiting example, including calcium carbonate, barium sulfate and / or silicon dioxide, talc, kaolin, boron nitride, magnesia, slags, silica, carbon black, carbon nanotubes, expanded or unexpanded graphite, titanium oxide which may be used as a nucleating agent (in pure form or in concentrated form, (e.g. CaCOs, ZnO, SiC>2) or combinations thereof).

[0107] Reinforcing fibers are selected from among other fibers, particularly short fibers. These fibers can be synthetic, such as glass or carbon fibers, or natural, typically plant-based, such as flax, reed, bamboo, or hemp fibers. Preferably, reinforcing fibers are glass fibers.

[0108] The composition may include from 0.05 to 10% by weight of one or more additives relative to the total weight of the composition.

[0109] The composition may include from 0.5 to 50% by weight of fillers relative to the total weight of the composition.

[0110] The composition may include from 5 to 75% by weight of reinforcing fibers relative to the total weight of the composition. The composition may include from 0.1 to 80% by weight of fillers, reinforcing fibers, and additives combined relative to the total weight of the composition.

[0111] Process for preparing branched polyamide

[0112] According to one aspect of the invention, the branched polyamide as defined above is prepared by a process comprising at least one step of mixing the monomer T with the monomers of a polyamide and a step of synthesizing the branched polyamide by polycondensation, preferably, the monomer T being mixed in an amount of 0.05 to 3% by mole, preferably 0.2 to 1% by mole, relative to the total number of moles of polyamide monomer.

[0113] This process can, for example, be carried out in an autoclave reactor.

[0114] According to one embodiment, a bifunctional co-monomer is mixed together with monomer T, preferably with the polyamide monomers, to obtain a polyamide having an absolute difference between its total acidity and its total basicity of less than 0.070 mEq / g.

[0115] The bifunctional co-monomer can typically be selected from a diamine or a diacid, for example, selected from a dicarboxylic acid, in particular those having 4 to 36 carbon atoms, preferably those having 4 to 20 carbon atoms, more preferably 6 to 18 carbon atoms, or an aliphatic, cycloaliphatic or aromatic diamine, preferably an aliphatic or cycloaliphatic diamine, in particular those having 2 to 20 carbon atoms, preferably those having 6 to 14 carbon atoms.

[0116] Examples of dicarboxylic acids include 1,4-cyclohexyldicarboxylic acid, butanedioic, adipic, azelaic, suberic, sebacic, dodecanedicarboxylic, octadecanedicarboxylic acids and terephthalic and isophthalic acids, as well as dimerized fatty acids.

[0117] Examples of diamines include tetramethylenediamine, hexamethylenediamine, 1,10-decamethylenediamine, dodecamethylenediamine, trimethylhexamethylenediamine, isomers of bis-(4-aminocyclohexyl)methane (BACM), bis-(3-methyl-4-aminocyclohexyl)methane (BMACM), and 2-2-bis-(3-methyl-4-aminocyclohexyl)propane (BMACP), para-amino-di-cyclohexylmethane (PACM), isophoronediamine (IPDA), 2,6-bis-(aminomethyl)norbornane (BAMN) and piperazine (Pip). According to another aspect, a branched polyamide according to the invention can be prepared according to a preparation process comprising a step of mixing a polyamide, a monomer T, and optionally a co-monomer, in the molten state and a step of extruding the mixture in the molten state.

[0118] The conditions applied to the mixing step must be chosen to allow for intimate mixing of the compounds in the molten state.

[0119] According to one embodiment, the process can be carried out by reactive extrusion, typically in an extruder.

[0120] To prepare a composition as described above, one or more additional polymers and / or one or more additives may be added during the aforementioned processes.

[0121] Any device for mixing, kneading or extruding molten plastics known to those skilled in the art may be used.

[0122] Foaming process and foam

[0123] The foam of the present invention can be prepared by a manufacturing process comprising:

[0124] - the supply of a mixture comprising branched polyamide as defined above, possibly with one or more additives, and with a blowing agent; and

[0125] - foaming of the mixture, possibly with one or more additives and expanding agent.

[0126] The blowing agent can be a chemical or physical agent, or a mixture of both. Preferably, it is a physical agent, such as nitrogen or carbon dioxide, or water, or a hydrocarbon, chlorofluorocarbon, hydrochlorocarbon, hydrofluorocarbon, or hydrochlorofluorocarbon (saturated or unsaturated). For example, butane or pentane can be used.

[0127] The foam thus formed consists essentially, or even consists, of the composition described above and optionally one or more additives dispersed in the matrix.

[0128] One or more of the additives may be the compounds described above.

[0129] In cases where a chemical blowing agent is used, the foam may include, in addition to the composition described above, the decomposition products of the chemical blowing agent, which are dispersed throughout the matrix. Foaming technologies may include those known to those skilled in the art, for example, batch foaming, injection foaming, extrusion foaming, autoclave foaming, and microwave foaming.

[0130] The step of supplying the mixture occurs either in solid state or in molten state.

[0131] Advantageously, the process according to the invention comprises a step of injecting said mixture into a mold and a step of foaming said mixture. The foaming is produced either during the injection into the mold of a volume of polymer smaller than that of the mold, or by opening the mold. These two techniques, each or in combination, make it possible to directly produce three-dimensional foamed objects with complex geometries.

[0132] Other injection foaming techniques that can be used within the framework of the present invention include injection foaming with a breathing mold, with application of a counter-pressure of gas, under dosing, or with a mold equipped with a Variotherm® system.

[0133] According to one embodiment, the foaming process according to the invention comprises a step of supplying the mixture in a molten state, and a step of extruding said mixture, inducing the foaming of said mixture directly at the outlet of the extrusion die.

[0134] In yet another embodiment, the foaming process comprises a step of impregnating an object made of a composition as described above with a gas, typically an inert gas, at a pressure above atmospheric pressure to force the gas into the object, and a step of reducing the pressure allowing the gas to dissipate and produce the foam. In this case, the object can typically be a particle, a part injected, or extruded from the composition.

[0135] According to yet another embodiment, the foaming process comprises a step of impregnating an object made of a composition as described above with a gas, typically an inert gas, at a pressure above atmospheric pressure to force the gas into the object, and a step of reducing the pressure to recover the unfoamed object. The object is then heated to produce the foam. In this case, the object can typically be a particle, a part injected, or extruded from the composition. The foam according to the invention preferably has a density less than or equal to 800 kg / m³. 3 , more preferably less than or equal to 600 kg / m 3 .

[0136] The foam according to the invention can be used to manufacture sports equipment, such as surfboards, such as soles for sports shoes, ski boots, midsoles, insoles, or functional components of soles, in the form of inserts in different parts of the sole (heel or arch for example), or components of shoe uppers in the form of reinforcements or inserts in the structure of the shoe upper, in the form of protections.

[0137] It can also be used to manufacture balls, sports gloves (e.g. football gloves), golf ball components, rackets, protective equipment (vests, helmet interiors, shells...).

[0138] The foam according to the invention exhibits interesting shock-absorbing, vibration-damping, and noise-reducing properties, combined with haptic properties suitable for capital goods. It can therefore also be used for the manufacture of railway track pads, insulation materials, or various components in the automotive, transportation, electrical and electronic equipment, construction, or manufacturing industries.

[0139] According to one embodiment, the foams according to the invention can be recycled, for example by melting them in an extruder equipped with a degassing outlet (optionally after cutting them into pieces).

[0140] Examples

[0141] The examples below illustrate the present invention without limiting its scope. In the examples, unless otherwise stated, all percentages and parts are expressed by weight.

[0142] Example 1: Preparation of polyamides

[0143] The polyamide designated C1 is PA 11. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0144] The polyamide designated C2 is a PA 11 / TMA (for PA X / Y and the examples below, X represents the type of polyamide, Y represents the type of monomer T and possibly that of the co-monomer). This polyamide is prepared according to the following procedure. After loading 40 g of 11-aminoundecanoic acid, 0.251 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 h. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0145] The polyamide designated C3 is PA 11 / 10TMA. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid, 0.026 g of 1,10-decanediamine, 0.021 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predetermined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0146] The polyamide designated C4 is PA 12. This polyamide is prepared according to the following process. After loading 40 g of 12-aminododecanoic acid and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0147] The polyamide designated C5 is PA 1010. This polyamide is prepared according to the following process. After loading 23.89 g of sebacic acid, 20.36 g of 1,10-decanediamine, and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 260°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0148] The polyamide designated A1 is a PA 11 / 10TMA. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid, 0.103 g of 1,10-decanediamine, 0.084 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predetermined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0149] The polyamide designated A2 is PA 11 / 10TMA. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid, 0.308 g of 1,10-decanediamine, 0.251 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predetermined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0150] The polyamide designated A3 is PA 11 / T40310. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid, 0.121 g of sebacic acid, 0.175 g of Jeffamine T403 (T403), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 250°C while maintaining stirring. The reaction mixture is maintained at 250°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0151] The polyamide designated A4 is PA 11 / T40310. This polyamide is prepared according to the following process. After loading 40 g of 11-aminoundecanoic acid, 0.482 g of sebacic acid, 0.699 g of Jeffamine T403 (T403), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 250°C while maintaining stirring. The reaction mixture is maintained at 250°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predefined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0152] The polyamide designated A5 is a PA 12 / 10TMA. This polyamide is prepared according to the following process. After loading 40 g of 12-aminododecanoic acid, 0.373 g of 1,10-decanediamine, 0.149 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 250°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predetermined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0153] The polyamide designated A6 is PA 1010 / 10TMA. This polyamide is prepared according to the following process. After loading 23.89 g of sebacic acid, 20.83 g of 1,10-decanediamine, 0.189 g of trimesic acid (TMA), and 2 g of water, the autoclave reactor is placed under an inert atmosphere. The reaction mixture is then heated to 270°C while maintaining stirring. The reaction mixture is maintained at 270°C under autogenous pressure for 1 hour. Then, the pressure is reduced to atmospheric pressure while maintaining the temperature at 260°C. The reactor is then subjected to nitrogen purging until the measured stirring torque reaches a predetermined value. The viscosity of the mixture is monitored by measuring the stirring torque. The material is then extruded into granules.

[0154] [Table 1]: Natures and proportions of monomers for the preparation of polyamides [Table 2]: Total basicity and acidity values

[0155] [Table 3]: SEC values ​​and molten strength coefficient (strain hardening coefficient). The molten strength coefficients (strain hardening coefficients) were measured at 215°C, corresponding to the final melting temperature of polyamides (Tf = 190°C). Examples A1 to A6 illustrate branched polyamides according to the invention.

[0156] For examples A1, A2, A5 and A6 the trimesic acid is a triacid, for examples A3 and A4, the Jeffamine T403 used is a polyethertriamine.

[0157] Branched polyamides A1 to A6 exhibit higher melt strength coefficients (strain hardening coefficients) than those of polyamides C1, C2, C3, C4 and C5.

[0158] Autoclave foaming tests with CO2 were performed on polyamides according to the following protocol. Discs injected from polyamides C1, C2, C4, C5, A1, A2, A4, A5, and A6 were placed in a hermetically sealed autoclave. The autoclave chamber was filled with CO2 to a saturation pressure of 250 bar and heated to the saturation temperature specified for each sample in Table 4. After 2 hours of saturation, the temperature was reduced to the foaming pressure specified in Table 4, and then the chamber was rapidly depressurized to quickly reach atmospheric pressure and induce foaming of the polyamide samples. The foamed samples were then collected, and their densities were measured at 23°C according to ASTM D792 using a hydrostatic balance with vertical thrust in water. The results are grouped in Table 4. Polymer foams obtained from branched polyamides A1, A2, A4, A5 to A6 have lower densities (<150 kg / m3) than polymer foams obtained from polyamides C1, C2, C4 and C5.

Claims

Demands 1. Branched polyamide, suitable for the preparation of a foam, in which the polyamide comprises branching points formed by a motif from a monomer T comprising x function(s) A and y function(s) B, A being a carboxylic acid function, B being an amine function, x representing the number of A functions, y representing the number of B functions, x and y being integers greater than or equal to 0 and x+y >=3, the branched polyamide having a weight average molar mass (Mw) greater than or equal to 60,000 g / mol, and the ratio of the z average molar mass (Mz) to the weight average molar mass (Mw) is greater than 1.

80.

2. Branched polyamide according to claim 1, wherein the weight average molar mass (Mw) of the branched polyamide is from 60,000 to 300,000 g / mol, preferably from 60,000 to 250,000 g / mol.

3. Branched polyamide according to claim 1 or 2, wherein the ratio of the average molar mass in z (Mz) to the average molar mass by weight (Mw) of the branched polyamide (“Iz”) is greater than or equal to 1.80, for example greater than or equal to 1.90, preferably greater than or equal to 2.00, for example greater than or equal to 2.

10.

4. Branched polyamide according to any one of claims 1 to 3, wherein the ratio of the weight average molar mass (Mw) of the polyamide to the number average molar mass (Mn) of the polyamide (“Ip”) is greater than 2.20, for example greater than or equal to 2.30, preferably greater than or equal to 2.40, for example greater than or equal to 2.50, even more preferably greater than or equal to 2.60, for example greater than or equal to 2.

80.

5. Branched polyamide according to any one of claims 1 to 4, wherein the polyamide is selected from a homopolyamide PA 11, 12, PA 610, PA 612, PA 614, PA 618, PA 910, PA 912, PA 106, PA 1010, PA 1011, PA 1012, PA 1014, PA 1018, and / or PA1036 or a copolyamide of these.

6. Branched polyamide according to any one of claims 1 to 5, in which x the number of function A or y the number of function B of monomer T is an integer equal to 0.

7. Branched polyamide according to any one of claims 1 to 6, wherein the monomer T is selected from a polyacid, a polyamine and a compound containing at least one amine function and at least one carboxylic acid function, preferably selected from trimesic acid, [2,2':6',2"-Terpyridine]-4,4',4"-tricarboxylic acid, 1,2-Diaminopropane-N,N,N',N-tetraacetic acid, Biphenyl-3,3',5,5'-tetracarboxylic acid, from polyamines, melamines, tri(aminoalkyl)amines, tris(2-aminoethyl)amine, polyalkylenetriamine, dialkylenetriamine, diethylenetriamine, polyethertriamine, α, co-amino acids and / or aniline dicarboxylate.

8. Branched polyamide according to any one of claims 1 to 7, comprising motifs from a bifunctional co-monomer selected from a diamine or a diacid, which may be selected from a dicarboxylic acid, in particular those having from 4 to 36 carbon atoms, or an aliphatic or cycloaliphatic diamine, in particular those having from 2 to 20 carbon atoms.

9. Branched polyamide according to any one of claims 1 to 8, wherein monomer T is present in the branched polyamide in an amount of 0.05 to 3% by mol, preferably 0.1 to 2%, more preferably 0.2 to 1% by mol, relative to the total number of moles of monomer T and monomers of the polyamide.

10. Branched polyamide according to any one of claims 1 to 9, having a difference in absolute value between its total acidity and its total basicity of less than 0.070 mEq / g.

11. Branched polyamide according to any one of claims 1 to 10, having a melt strength coefficient (strain hardening coefficient) greater than 1.0, preferably greater than 1.

3.

12. A method for preparing a branched polyamide according to any one of the claims 1 to 11, comprising at least one step of mixing monomer T with monomers of a polyamide and a step of synthesizing branched polyamide by polycondensation, preferably monomer T being mixed in an amount of 0.05 to 3 mol%, preferably 0.2 to 1 mol%, relative to the total number of moles of monomer T and polyamide monomers.

13. A process according to claim 12, wherein a bifunctional co-monomer is mixed together with monomer T, to the polyamide monomers.

14. A method according to claim 13, wherein the bifunctional co-monomer is selected from a diamine or a diacid, which may be selected from a dicarboxylic acid, in particular those having from 4 to 36 carbon atoms, or an aliphatic, cycloaliphatic or aromatic diamine, in particular those having from 2 to 20 carbon atoms.

15. Composition comprising a branched polyamide according to any one of claims 1 to 11, and one or more additive polymers, one or more additives, fillers, and / or reinforcing fibers.

16. Article made of a branched polyamide according to any one of claims 1 to 11 or of a composition according to claim 15.

17. Article according to claim 16 being a foam, preferably having a density less than or equal to 800 kg / m³ 3 , preferably less than or equal to 600 kg / m 3 , preferably less than or equal to 150 kg / m 3 .

18. Article according to one of claims 16 or 17, being selected from sports shoe soles, balls or balloons, gloves, personal protective equipment, rail soles, automotive parts, construction parts and electrical and electronic equipment parts.

19. A method for manufacturing a foam according to claim 17, comprising the following steps: - the supply of a mixture comprising branched polyamide, possibly with one or more additives, and with a blowing agent; and - foaming of the mixture, possibly with one or more additives and expanding agent.

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