Branched rigid copolymer and soft block copolymer

Abstract

The present invention relates to branched hard copolymers and soft block copolymers, wherein the branching is provided by polyol residues of the copolymer attached to the hard blocks, the polyol containing at least three hydroxyl groups, the copolymer having a weight-average molar mass Mw of 80,000 g / mol or more, and the ratio of the weight-average molar mass Mw of the copolymer to the number-average molar mass Mn of the copolymer is 2.2 or more. The present invention also relates to methods for producing such copolymers and foams of such copolymers, to methods for producing such foams, and to articles produced from such foams.

Description

Technical Field

[0001] The present invention relates to a copolymer containing rigid blocks and flexible blocks and a foam formed from this copolymer.

Background Art

[0002] Various polymer foams are used especially in the field of sports equipment, for example, shoe soles or shoe sole components, gloves, rackets or golf balls, particularly personal protective items (jackets, inner parts of helmets, covers, etc.) when performing sports.

[0003] For such applications, a series of specific physical properties are required to ensure resilience, low compression strain, and the ability to withstand repeated shocks without deforming and recover to the initial shape.

[0004] In document CN 107325280, a polyether / polyamide elastomer obtained by copolymerization of polyamide, polyether, and a branching agent and capable of being used for the preparation of foams is described.

[0005] In document WO 2018 / 087501, a composition comprising a copolymer containing flexible blocks and rigid blocks and a polyol having more than two functional groups, and their use in an extrusion process, particularly for the production of moisture-permeable waterproof films, are described.

[0006] There is a need to provide a polymer that enables the formation of a foam having one or more advantageous properties from among low density; low compression strain; high fatigue strength during compression; and good elasticity.

Summary of the Invention

[0007] The present invention firstly provides a branched copolymer containing rigid blocks and flexible blocks, wherein the branches are made by polyol residues that bond the rigid blocks of the copolymer, The polyol is a polyol containing at least three hydroxyl groups, The copolymer relates to a branched copolymer containing a rigid block and a flexible block, which has a weight average molecular weight Mw of 80,000 g / mol or more, and the ratio of the weight average molecular weight Mw of the copolymer to the number average molecular weight Mn of the copolymer is 2.2 or more.

[0008] According to a specific embodiment, the copolymer has a weight average molecular weight Mw in the range of 80,000 to 300,000 g / mol, preferably 85,000 to 200,000 g / mol, more preferably 90,000 to 175,000 g / mol.

[0009] According to a specific embodiment, the ratio of the weight average molecular weight Mw of the copolymer to the number average molecular weight Mn of the copolymer is 2.4 or more.

[0010] According to a specific embodiment, the ratio of the z-average molar mass Mz of the copolymer to the weight average molecular weight Mw of the copolymer is 1.8 or more, preferably 2 or more.

[0011] According to a specific embodiment, the rigid block is selected from a polyamide block, a polyester block, a polyurethane block, and combinations thereof.

[0012] According to a specific embodiment, the flexible block is selected from a polyether block, a polyester block, and combinations thereof.

[0013] According to a specific embodiment, the copolymer is a copolymer containing a polyamide block and a polyether block.

[0014] According to certain embodiments, the polyamide block is a block of polyamide 6, polyamide 11, polyamide 12, polyamide 5.4, polyamide 5.9, polyamide 5.10, polyamide 5.12, polyamide 5.13, polyamide 5.14, polyamide 5.16, polyamide 5.18, polyamide 5.36, polyamide 6.4, polyamide 6.9, polyamide 6.10, polyamide 6.12, polyamide 6.13, polyamide 6.14, polyamide 6.16, polyamide 6.18, polyamide 6.36, polyamide 10.4, polyamide 10.9, polyamide 10.10, polyamide 10.12, polyamide 10.13, polyamide 10.14, polyamide 10.16, polyamide 10.18, polyamide 10.36, polyamide 10.T, polyamide 12.4, polyamide 12.9, polyamide 12.10, polyamide 12.12, polyamide 12.13, polyamide 12.14, polyamide 12.16, polyamide 12.18, polyamide 12.36, polyamide 12.T or a mixture thereof, or a copolymer thereof, preferably a block of polyamide 11, polyamide 12, polyamide 6 or polyamide 6.10.

[0015] According to certain embodiments, the polyether block is a block of polyethylene glycol, propylene glycol, polytetramethylene glycol, polytetrahydrofuran, or a mixture thereof, or a copolymer thereof, preferably a block of polyethylene glycol or polytetrahydrofuran.

[0016] According to certain embodiments: - The rigid block of the copolymer has a number average molecular weight of 400 to 20,000 g / mol, preferably 500 to 10,000 g / mol; and / or - The flexible block of the copolymer has a number average molecular weight of 100 to 6000 g / mol, preferably 200 to 3000 g / mol.

[0017] According to certain embodiments, the mass ratio of the rigid block to the flexible block of the copolymer is from 0.1 to 20, preferably from 0.3 to 3, and even more preferably from 0.3 to 0.9.

[0018] According to certain embodiments, the polyol has a weight average molecular weight in the range of 3000 g / mol or less, preferably 2000 g / mol or less, and more preferably from 50 to 1000 g / mol.

[0019] According to certain embodiments, the polyol is selected from pentaerythritol, trimethylolpropane, trimethylolethane, hexanetriol, diglycerol, methyl glucoside, tetraethanol, sorbitol, dipentaerythritol, cyclodextrin, polyether polyols containing at least 3 hydroxyl groups, and mixtures thereof.

[0020] The present invention also relates to a foam of a copolymer containing the above-mentioned rigid block and flexible block.

[0021] According to certain embodiments, the foam has a density of 800 kg / m 3 or less, preferably 600 kg / m 3 or less, more preferably 400 kg / m 3 or less, and even more preferably 300 kg / m 3 or less.

[0022] According to certain embodiments, the foam has a compression strain after 30 minutes of 35% or less, preferably 30% or less.

[0023] The present invention also relates to the following steps: - Mixing a precursor of the rigid block and a polyol; - Synthesizing the rigid block; - Adding the flexible block; - Condensing the rigid block and the flexible block, and relates to a method for producing a copolymer containing the above-mentioned rigid block and flexible block.

[0024] According to certain embodiments, the polyol is mixed in an amount in the range of 0.01 wt% to 10 wt%, preferably 0.01 wt% to 5 wt%, more preferably 0.05 wt% to 0.5 wt%, based on the total weight of the polyol, the precursor of the rigid block, and the flexible block.

[0025] The present invention also relates to the following steps: - mixing the copolymer in the molten state, optionally with one or more additives and a blowing agent; and - foaming the mixture of the copolymer and the blowing agent, and relates to a method for producing the above foam.

[0026] The present invention also relates to an article made of the above foam.

[0027] The present invention also relates to an article comprising at least one element made of the above foam.

[0028] According to certain embodiments, the article is selected from the sole of a sports shoe, a large or small ball, a glove, personal protective gear, a rail tie pad, automotive parts, construction parts, and electrical and electronic equipment parts.

[0029] The present invention makes it possible to meet the needs specified above. More specifically, the present invention provides a copolymer containing a rigid block and a flexible block, which has improved foamability and enables the formation of a polymer foam with uniform regularity, wherein the foam is of low density and has one or more advantageous properties among a high ability to recover elastic energy under low stress loading; low compression strain (thus improved durability); high fatigue strength during compression; and excellent elasticity. According to certain specific embodiments, the foam according to the present invention is also recyclable.

[0030] This is achieved using a copolymer containing rigid blocks and flexible blocks having a specific weight average molecular weight and a specific polydispersity, the copolymer being branched by specific polyol residues that bind to the rigid blocks of the copolymer.

Mode for Carrying Out the Invention

[0031] Next, the present invention will be described in more detail and non - limitatively in the following description.

[0032] Unless otherwise indicated, all percentages are by mass.

[0033] The present invention relates to rigid blocks and flexible blocks. These copolymers are thermoplastic elastomer (TPE) polymers containing blocks that are rigid (or hard and rather have the behavior of a thermoplastic resin) and blocks that are flexible (or soft and rather have an elastomeric behavior).

[0034] The "rigid block" is understood to mean a block having a melting point. The presence of a melting point can be determined by differential scanning calorimetry in accordance with ISO standard 11357 - 3:2011 Plastics - Differential scanning calorimetry (DSC) - Part 3.

[0035] The "soft block" is understood to mean a block having a glass transition temperature (Tg) of 0 °C or lower. The glass transition temperature can be determined by differential scanning calorimetry in accordance with ISO standard 11357 - 2:2011 Plastics - Differential scanning calorimetry (DSC) - Part 2.

[0036] The rigid blocks of the copolymers according to the present invention are preferably selected from polyamide blocks, polyester blocks, polyurethane blocks and combinations thereof. Such blocks are described, for example, in French patent application FR 2936803 A1.

[0037] Preferably, the rigid block is a polyamide block.

[0038] Three types of polyamide blocks can be advantageously used.

[0039] According to the first type, the polyamide block is derived from the condensation of a dicarboxylic acid, in particular one containing 4 to 20 carbon atoms, preferably one containing 6 to 18 carbon atoms, and an aliphatic or aromatic diamine, in particular one containing 2 to 20 carbon atoms, preferably one containing 6 to 14 carbon atoms.

[0040] Examples of dicarboxylic acids include 1,4-cyclohexanedicarboxylic acid, butanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, terephthalic acid and isophthalic acid, and dimerized fatty acids.

[0041] Examples of diamines include tetramethylenediamine, hexamethylenediamine, 1,10-decamethylenediamine, 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), para-aminodicyclohexylmethane (PACM), isophoronediamine (IPDA), 2,6-bis(aminomethyl)norbornane (BAMN) and piperazine (Pip).

[0042] Advantageously, polyamide blocks, PA 4.12, PA 4.14, PA 4.18, PA 6.10, PA 6.12, PA 6.14, PA 6.18, PA 9.12, PA 10.10, PA 10.12, PA 10.14 and PA 10.18, are used. In the notation PA X.Y, as usual, X represents the number of carbon atoms derived from the diamine residue and Y represents the number of carbon atoms derived from the diacid residue.

[0043] According to the second type, the polyamide block is produced from the condensation of one or more α,ω-aminocarboxylic acids and / or one or more lactams containing 6 to 12 carbon atoms in the presence of a dicarboxylic acid or a diamine containing 4 to 12 carbon atoms. Examples of lactams include caprolactam, enantholactam, and lauryllactam. Examples of α,ω-aminocarboxylic acids include aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0044] Advantageously, the polyamide block of the second type is each block of PA 11 (polyundecanamide), PA 12 (polydodecanamide), or PA 6 (polycaprolactam). In the notation PA X, X represents the number of carbon atoms derived from the amino acid residue.

[0045] According to the third type, the polyamide block is produced from the condensation of at least one α,ω-aminocarboxylic acid (or lactam), at least one diamine, and at least one dicarboxylic acid.

[0046] In this case, the polyamide PA block is: - of a linear aliphatic or aromatic diamine containing X carbon atoms; - of a dicarboxylic acid containing Y carbon atoms; and - of a lactam and α,ω-aminocarboxylic acid containing Z carbon atoms and at least one diamine containing X1 carbon atoms and at least one dicarboxylic acid containing Y1 carbon atoms, where (X1, Y1) is an equimolar mixture different from (X, Y), of the comonomer {Z}, is a polycondensation; - the comonomer {Z} is introduced in a weight ratio in the range of advantageously up to 50%, preferably up to 20%, and even more preferably up to 10% with respect to the total amount of the polyamide precursor monomers; - in the presence of a chain limiter selected from dicarboxylic acids, It is prepared by polycondensation.

[0047] Advantageously, a dicarboxylic acid containing Y carbon atoms is used as a chain limiter, which is introduced in excess with respect to the stoichiometry of the diamine.

[0048] According to this third type of variant form, the polyamide block is produced from the condensation of at least two α,ω - aminocarboxylic acids, or from the condensation of at least two lactams containing 6 to 12 carbon atoms, or from the condensation of one lactam and one aminocarboxylic acid having the same number of carbon atoms, optionally in the presence of a chain limiter. Examples of aliphatic α,ω - aminocarboxylic acids include aminocaproic acid, 7 - aminoheptanoic acid, 11 - aminoundecanoic acid, and 12 - aminododecanoic acid. Examples of lactams include caprolactam, enantholactam, and lauryllactam. Examples of aliphatic diamines include hexamethylenediamine, dodecamethylenediamine, and trimethylhexamethylenediamine. Examples of alicyclic diacids include 1,4 - cyclohexanedicarboxylic acid. Examples of aliphatic diacids include butanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, and dimerized fatty acids. These dimerized fatty acids preferably have a dimer content of at least 98%; are preferably hydrogenated; are products sold, for example, under the brand name Pripol by Croda, or under the brand name Empol by BASF, or under the brand name Radiacid by Oleon, and are polyoxyalkylene α,ω - diacids. Examples of aromatic diacids include terephthalic acid (T) and isophthalic acid (I). Examples of alicyclic diamines include 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), as well as para - aminodicyclohexylmethane (PACM). Other diamines commonly used can be isophoronediamine (IPDA), 2,6 - bis(aminomethyl)norbornane (BAMN), and piperazine.

[0049] Examples of the third type of polyamide block include the following: - PA 6.6 / 6, where 6.6 represents the hexamethylenediamine units condensed with adipic acid and 6 represents the units produced from the condensation of caprolactam; - PA 6.6 / 6.10 / 11 / 12, where 6.6 represents hexamethylenediamine condensed with adipic acid, 6.10 represents hexamethylenediamine condensed with sebacic acid, 11 represents the units produced from the condensation of aminoundecanoic acid, and 12 represents the units produced from the condensation of lauryllactam.

[0050] The notations PA X / Y, PA X / Y / Z, etc. relate to copolyamides where X, Y, Z, etc. represent the above-mentioned homopolyamide units.

[0051] Advantageously, the polyamide blocks of the copolymer used in the present invention include blocks of polyamide PA 6, PA 11, PA 12, PA 5.4, PA 5.9, PA 5.10, PA 5.12, PA 5.13, PA 5.14, PA 5.16, PA 5.18, PA 5.36, PA 6.4, PA 6.9, PA 6.10, PA 6.12, PA 6.13, PA 6.14, PA 6.16, PA 6.18, PA 6.36, PA 10.4, PA 10.9, PA 10.10, PA 10.12, PA 10.13, PA 10.14, PA 10.16, PA 10.18, PA 10.36, PA 10.T, PA 12.4, PA 12.9, PA 12.10, PA 12.12, PA 12.13, PA 12.14, PA 12.16, PA 12.18, PA 12.36 or PA 12.T, or mixtures or copolymers thereof; preferably, blocks of polyamide, PA 6, PA 11, PA 12, PA 6.10, PA 10.10 or PA 10.12, or mixtures or copolymers thereof.

[0052] The flexible blocks of the copolymer according to the invention can in particular be selected from polyether blocks, polyester blocks, polysiloxane blocks such as polydimethylsiloxane (or PDMS) blocks, polyolefin blocks, polycarbonate blocks, and mixtures thereof.

[0053] Possible flexible blocks are described, for example, in French patent application FR 2941700 A1, pages 32, line 3 to page 33, line 15, page 34, line 16 to page 37, line 13, and page 38, line 6 to line 23.

[0054] Preferably, the flexible blocks are selected from polyether blocks, polyester blocks, and combinations thereof.

[0055] Particularly advantageously, the flexible block is a polyether block.

[0056] The polyether block is formed from alkylene oxide units.

[0057] The polyether block can in particular be a PEG (polyethylene glycol) block, i.e., a block formed from ethylene oxide units, and / or a PPG (propylene glycol) block, i.e., a block formed from propylene oxide units, and / or a PO3G (polytrimethylene glycol) block, i.e., a block formed from polytrimethylene glycol ether units, and / or a PTMG (polytetramethylene glycol) block, i.e., a block formed from tetramethylene glycol units also known as polytetrahydrofuran. The copolymer can contain several types of polyethers in its chains, and the copolyether can be in block form or in statistical form.

[0058] It is also possible to use blocks obtained by oxyethylation of bisphenols, for example bisphenol A. The latter products are described inter alia in EP 613 919.

[0059] The polyether block can also be formed from ethoxylated primary amines. Examples of ethoxylated primary amines are products of the formula: TIFF0007708665000001.tif37170 [where m and n are integers between 1 and 20 and x is an integer between 8 and 18]. These products are commercially available, for example, under the brand name Noramox® from CECA and under the brand name Genamin® from Clariant.

[0060] The flexible polyether block can include a polyoxyalkylene block having an NH2 chain end, and such a block can be obtained by cyanoacetylation of an α,ω-dihydroxylated aliphatic polyoxyalkylene block called a polyether diol. More specifically, commercially available products Jeffamine or Elastamine can be used (for example, Jeffamine® D400, D2000, ED 2003, XTJ 542, which are commercially available products of Huntsman Corporation, and are also described in JP 2004 / 346274, JP 2004 / 352794 and EP 1482011).

[0061] The polyether diol block is used in an unmodified form and is either co-polycondensed with a rigid block having a carboxyl end group or aminated to be converted into a polyether diamine and condensed with a rigid block having a carboxyl end group.

[0062] Preferably, the copolymer according to the invention is a copolymer containing a polyester block and a polyether block (also called COPE or copolyether ester), a copolymer containing a polyurethane block and a polyether block (also called TPU or thermoplastic resin polyurethane), or a copolymer containing a polyamide block and a polyether block (referred to as PEBA according to IUPAC or otherwise polyether-block-amide).

[0063] The above block copolymers contain at least one rigid block and at least one flexible block as described above. On the other hand, the present invention also covers copolymers containing three, four (or even more) different blocks selected from the blocks described in this description, provided that these blocks include at least a rigid block and a flexible block.

[0064] For example, the copolymer according to the invention can be a segmented block copolymer (or "triblock" copolymer) containing three different types of blocks, which is formed from the condensation of some of the above blocks. The triblock can be, for example, a copolymer containing a polyamide block, a polyester block and a polyether block, or a copolymer containing a polyamide block and two different polyether blocks, for example, a PEG block and a PTMG block.

[0065] Particularly preferably, the copolymer according to the invention is a copolymer containing a polyamide block and a polyether block (or PEBA).

[0066] PEBA is obtained from the polycondensation of a polyamide block having a reactive end with a polyether block having a reactive end, for example, in particular: 1) of a polyamide block having a diamine chain end with a polyoxyalkylene block having a dicarboxyl chain end; 2) For example, obtained by the cyanoethylation and hydrogenation of an α,ω-dihydroxylated aliphatic polyoxyalkylene block known as a polyether diol, of a polyamide block having a dicarboxyl chain end with a polyoxyalkylene block having a diamine chain end; 3) Wherein the resulting product is, in this particular case, a polyether ester amide, of a polyamide block having a dicarboxyl chain end with a polyether diol, is produced from polycondensation.

[0067] The polyamide block having a dicarboxyl chain end is derived, for example, from the condensation of a polyamide precursor in the presence of a chain-limiting dicarboxylic acid. The polyamide block having a diamine chain end is derived, for example, from the condensation of a polyamide precursor in the presence of a chain-limiting diamine.

[0068] Particularly preferred PEBA copolymers in the context of the present invention are copolymers comprising blocks from among the following: - PA 11 and PEG; - PA 11 and PTMG; - PA 12 and PEG; - PA 12 and PTMG; - PA 6.10 and PEG; - PA 6.10 and PTMG; - PA 6 and PEG; - PA 6 and PTMG.

[0069] The number average molecular weight of the rigid block in the copolymer according to the present invention is preferably 400 to 20,000 g / mol, more preferably 500 to 10,000 g / mol, and even more preferably 600 to 6000 g / mol. In certain embodiments, the number average molecular weight of the rigid block in the PEBA copolymer is 400 to 500 g / mol, or 500 to 1000 g / mol, or 1000 to 1500 g / mol, or 1500 to 2000 g / mol, or 2000 to 2500 g / mol, or 2500 to 3000 g / mol, or 3000 to 3500 g / mol, or 3500 to 4000 g / mol, or 4000 to 5000 g / mol, or 5000 to 6000 g / mol, or 6000 to 7000 g / mol, or 7000 to 8000 g / mol, or 8000 to 9000 g / mol, or 9000 to 10,000 g / mol, or 10,000 to 11,000 g / mol, or 11,000 to 12,000 g / mol, or 12,000 to 13,000 g / mol, or 13,000 to 14,000 g / mol, or 14,000 to 15,000 g / mol, or 15,000 to 16,000 g / mol, or 16,000 to 17,000 g / mol, or 17,000 to 18,000 g / mol, or 18,000 to 19,000 g / mol, or 19,000 to 20,000 g / mol.

[0070] The number average molecular weight of the flexible block is preferably 100 to 6000 g / mol, more preferably 200 to 3000 g / mol. In certain embodiments, the number average molecular weight of the flexible block is 100 to 200 g / mol, or 200 to 500 g / mol, or 500 to 800 g / mol, or 800 to 1000 g / mol, or 1000 to 1500 g / mol, or 1500 to 2000 g / mol, or 2000 to 2500 g / mol, or 2500 to 3000 g / mol, or 3000 to 3500 g / mol, or 3500 to 4000 g / mol, or 4000 to 4500 g / mol, or 4500 to 5000 g / mol, or 5000 to 5500 g / mol, or 5500 to 6000 g / mol.

[0071] The number average molecular weight is set by the content of the chain limiter. This can be calculated according to the following formula: M n =n モノマー ×MW 反復単位 / n 連鎖制限剤 +MW 連鎖制限剤

[0072] In this formula, n モノマー represents the number of moles of the monomer, n 連鎖制限剤 represents the number of moles of the excess diacid limiter, MW 反復単位 represents the molar mass of the repeating unit, MW 連鎖制限剤 represents the molar mass of the excess diacid.

[0073] The number average molecular weights of the rigid block and the flexible block can be measured by gel permeation chromatography (GPC) before the copolymerization of both blocks.

[0074] Advantageously, the mass ratio of the rigid block to the flexible block of the copolymer is 0.1 to 20, preferably 0.3 to 3, and even more preferably 0.3 to 0.9. In particular, the mass ratio of the rigid block to the flexible block of the copolymer can be 0.1 to 0.2, or 0.2 to 0.3, or 0.3 to 0.4, or 0.4 to 0.5, or 0.5 to 0.6, or 0.6 to 0.7, or 0.7 to 0.8, or 0.8 to 0.9, or 0.9 to 1, or 1 to 1.5, or 1.5 to 2, or 2 to 2.5, or 2.5 to 3, or 3 to 3.5, or 3.5 to 4, or 4 to 4.5, or 4.5 to 5, or 5 to 5.5, or 5.5 to 6, or 6 to 6.5, or 6.5 to 7, or 7 to 7.5, or 7.5 to 8, or 8 to 8.5, or 8.5 to 9, or 9 to 9.5, or 9.5 to 10, or 10 to 11, or 11 to 12, or 12 to 13, or 13 to 14, or 14 to 15, or 15 to 16, or 16 to 17, or 17 to 18, or 18 to 19, or 19 to 20.

[0075] Preferably, the copolymer of the present invention has an instantaneous hardness of 72 Shore D or less, more preferably 68 Shore D or less. The hardness measurement can be carried out in accordance with ISO standard 868:2003.

[0076] The copolymer according to the present invention is a branched copolymer. This is characterized by more than two functional groups and a broad molar mass distribution.

[0077] The branched copolymer containing a rigid block and a flexible block has a weight-average molecular weight Mw of more than 80,000 g / mol. Preferably, the weight-average molecular weight of the copolymer is from 80,000 to 300,000 g / mol, more preferably from 85,000 to 200,000 g / mol, even more preferably from 90,000 to 175,000 g / mol. The weight-average molecular weight is expressed as PMMA equivalent (used as a calibration standard) and can be measured by size exclusion chromatography in accordance with ISO standard 16014-1:2012. The copolymer is dissolved in hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate at a concentration of 1 g / L at room temperature for 24 hours, and then passed through the column, for example, at a flow rate of 1 ml / min, and the molar mass is measured by refractive index. A series of two columns and a pre-column of modified silica, for example, a 1000 Å column having dimensions of 300×8 mm and a particle size of 7 μm, a 100 Å column having dimensions of 300×8 mm and a particle size of 7 μm, and a pre-column having dimensions of 50×8 mm (for example, PGF columns and pre-columns manufactured by Polymer Standards Service), can be used to perform size exclusion chromatography, for example, at a temperature of 40°C. In certain embodiments, the branched copolymer containing a rigid block and a flexible block has a weight-average molecular weight Mw in the range of 80,000 to 90,000 g / mol, or 90,000 to 100,000 g / mol, or 100,000 g / mol to 125,000 g / mol, or 125,000 to 150,000 g / mol, or 150,000 to 175,000 g / mol, or 175,000 to 200,000 g / mol, or 200,000 to 225,000 g / mol, or 225,000 to 250,000 g / mol, or 250,000 to 275,000 g / mol, or 275,000 to 300,000 g / mol.

[0078] The branched copolymer containing rigid blocks and flexible blocks can have a number average molecular weight Mn in the range of 30,000 to 100,000 g / mol, preferably 35,000 to 80,000 g / mol, more preferably 40,000 to 70,000 g / mol. The number average molecular weight is expressed as PMMA equivalent and can be measured in accordance with ISO standard 16014-1 according to the above method. In certain embodiments, the branched copolymer containing rigid blocks and flexible blocks has a number average molecular weight Mn in the range of 30,000 to 35,000 g / mol, or 35,000 to 40,000 g / mol, or 40,000 to 45,000 g / mol, or 45,000 to 50,000 g / mol, or 50,000 to 55,000 g / mol, or 55,000 to 60,000 g / mol, or 60,000 to 70,000 g / mol, or 70,000 to 80,000 g / mol, or 80,000 to 90,000 g / mol, or 90,000 to 100,000 g / mol.

[0079] The branched copolymer containing rigid blocks and flexible blocks has a z-average molar mass Mz in the range of 200,000 to 500,000 g / mol. The z-average molar mass is expressed as PMMA equivalent and can be measured in accordance with ISO standard 16014-1 according to the above method. In certain embodiments, the branched copolymer containing rigid blocks and flexible blocks has a z-average molar mass Mz in the range of 200,000 to 250,000 g / mol, or 250,000 to 300,000 g / mol, or 300,000 to 350,000 g / mol, or 350,000 to 400,000 g / mol, or 400,000 to 450,000 g / mol, or 450,000 to 500,000 g / mol.

[0080] The polydispersity of the copolymer can be defined by the ratio of the weight average molecular weight Mw of the copolymer to the number average molecular weight Mn of the copolymer (Mw / Mn molar ratio) and / or by the ratio of the z-average molar mass Mz of the copolymer to the weight average molecular weight Mw of the copolymer (Mz / Mw molar ratio).

[0081] The copolymer according to the present invention has an Mw / Mn molar mass ratio of 2.2 or more, preferably 2.4 or more. In certain embodiments, the copolymer has an Mw / Mn molar mass ratio of 2.3 or more, or 2.4 or more, or 2.5 or more, or 2.6 or more, or 2.7 or more, or 2.8 or more, or 2.9 or more, or 3 or more.

[0082] The copolymer according to the present invention can have an Mw / Mn molar mass ratio of 7 or less, preferably 6.5 or less, more preferably 6 or less.

[0083] The copolymer according to the present invention can have an Mz / Mw molar mass ratio of 1.8 or more, preferably 2 or more. In certain embodiments, the copolymer has an Mz / Mw molar mass ratio of 1.9 or more, or 2 or more, or 2.1 or more, or 2.2 or more, or 2.3 or more, or 2.4 or more, or 2.5 or more.

[0084] The copolymer according to the present invention can have an Mz / Mw molar mass ratio of 5 or less, preferably 4.5 or less, preferably 4 or less.

[0085] Synthesis of the Copolymer The copolymer according to the present invention is prepared by addition during the synthesis of one or more polyols containing at least 3 hydroxyl groups.

[0086] In general and well-known methods, polymers containing rigid blocks and flexible blocks can be prepared according to a two-step preparation method (including a first step of synthesizing the rigid block and then a second step of condensing the rigid block and the flexible block), or by a one-step preparation method. The polyol is added together with the precursor of the rigid block.

[0087] Two-step preparation of a PEBA copolymer having an ester bond between the PA block and the PE block (i.e., the first step of the synthesis of the polyamide block, followed by the second step of the condensation of the polyamide block and the polyether block) is a general method known, for example, from document FR 2846332. A general method for the preparation of a PEBA copolymer having an amide bond between the PA block and the PE block is known, for example, from document EP 1482011. The polyether block can also be mixed with a polyamide precursor and a diacid chain limiter to prepare a polymer containing polyamide blocks and polyether blocks with randomly distributed units (one-step method). Regardless of the method used (two-step or one-step), the polyol is added together with the polyamide precursor.

[0088] Preferably, the copolymer according to the invention is prepared according to a two-step preparation method. Preferably, the copolymer according to the invention is prepared according to a method comprising the following steps: - mixing a precursor of the rigid block and a polyol; - synthesis of the rigid block; - addition of the flexible block; - condensation of the rigid block and the flexible block.

[0089] By adding a polyol having more than two functional groups, preferably by an ester bond, a crosslinking bond is formed that connects the rigid blocks of the copolymer together.

[0090] A polyol containing at least three hydroxyl groups is understood to particularly mean the following: - monomeric polyols, in particular monomeric aliphatic triols such as glycerol, trimethylolpropane, pentaerythritol, and / or - polymeric polyols, in particular triols containing a polyether chain, polycaprolactone triol, mixed polyether-polyester polyols containing at least three hydroxyl groups.

[0091] Advantageously, the polyol is selected from pentaerythritol, trimethylolpropane, trimethylolethane, hexanetriol, diglycerol, methyl glucoside, tetraethanol, sorbitol, dipentaerythritol, cyclodextrin, polyether polyols containing at least three hydroxyl groups, and mixtures thereof.

[0092] The weight average molecular weight of the polyol is preferably at most 3000 g / mol, more preferably at most 2000 g / mol; and generally ranges from 50 to 1000 g / mol, preferably from 50 to 500 g / mol, preferably from 50 to 200 g / mol.

[0093] Advantageously, the polyol is added in an amount of 0.01 wt% to 10 wt%, preferably 0.01 wt% to 5 wt%, more preferably 0.05 wt% to 0.5 wt%, based on the total weight of the polyol, the precursor of the rigid block and the flexible block. The polyol is advantageously added in an amount of 3.5 to 35 μeq / g based on the total weight of the polyol, the precursor of the rigid block and the flexible block.

[0094] Foam The branched copolymer containing the rigid block and the flexible block can preferably be used to form a foam without a crosslinking step. The foam is formed by mixing the copolymer in a molten state with a blowing agent and then performing a subsequent foaming step.

[0095] According to certain embodiments, the foam thus formed consists essentially of, or even consists of, the above copolymer (or, if a mixture of copolymers is used, a plurality of copolymers), optionally together with a blowing agent, especially when the blowing agent remains present in the pores of the foam, especially when the foam has closed pores.

[0096] Copolymers containing rigid blocks and flexible blocks can be combined with various additives, such as copolymers of ethylene and vinyl acetate or EVA (e.g., those sold under the name Evatane® by Arkema), or copolymers of ethylene and acrylate, or copolymers of ethylene and alkyl (meth)acrylate, such as those sold under the name Lotryl® by Arkema. These additives can make it possible to adjust the hardness, appearance, and comfort of the foamed parts. The additives can be added to the copolymer containing rigid blocks and flexible blocks in a content of 0 to 50% by mass, preferably 5% to 30% by mass.

[0097] The blowing agent can be a chemical agent or a physical agent, or can consist of any type of hollow body or any type of foaming microsphere. Preferably, the blowing agent is a physical agent, such as nitrogen or carbon dioxide, or hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, or hydrochlorofluorocarbons (saturated or unsaturated). For example, butane or pentane can be used. Also preferably, the blowing agent can also be a chemical agent, such as a mixture based on azodicarbonamide or citric acid and sodium bicarbonate (NaHCO3) (products within the range of Hydrocerol® manufactured by Clariant).

[0098] The physical blowing agent is mixed with the copolymer in liquid or supercritical form and then converted to the gas phase during the foaming process.

[0099] According to a preferred embodiment, a mixture of the copolymer and the blowing agent is injected into a mold and foamed by opening the mold. This technique makes it possible to directly manufacture three-dimensional foamed articles with complex shapes.

[0100] This is also a technique that is relatively easy to implement, especially when compared to certain methods of melting the foamed particles described in the prior art: Specifically, filling a mold with foamed polymer granules and subsequently melting the particles to ensure the mechanical strength of the part without destroying the structure of the foam is a difficult operation.

[0101] Other foaming techniques that can be used include, in particular, "batch" foaming, extrusion foaming such as uniaxial or biaxial extrusion foaming, autoclave foaming, microwave foaming, and other injection molding foaming techniques (using a vented mold with the application of gas backpressure under metering, or a mold equipped with a Variotherm® system).

[0102] The foam according to the present invention preferably has a density of 800 kg / m 3 Hereinafter, more preferably 600 kg / m 3 Hereinafter, even more preferably 400 kg / m 3 Hereinafter, particularly preferably 300 kg / m 3 or less. The foam according to the present invention can have, for example, a density of 25 to 800 kg / m 3 , more particularly preferably 50 to 600 kg / m 3 . The density can be controlled by adapting the parameters of the manufacturing method.

[0103] Preferably, the foam has a resilience of 50% or more, preferably 55% or more, in accordance with ISO standard 8307:2007.

[0104] Preferably, the foam has a compression set after 30 minutes of 35% or less, more particularly preferably 30% or less, or 25% or less, in accordance with ISO standard 7214:2012.

[0105] Preferably, the foam also has excellent properties in terms of fatigue strength and damping.

[0106] The foam according to the invention can be used to manufacture sports equipment such as components of the soles of sports shoes, ski boots, midsoles, insoles or functional soles in the form of inserts in various parts of the shoe sole (such as the heel and arch), or, alternatively, components of the upper part of the shoe in the form of reinforcements or inserts in the structure of the upper part of the shoe or in the form of protective elements.

[0107] The foam according to the invention can also be used to manufacture inflatable balls, sports gloves (such as soccer gloves), golf ball components, rackets, protective elements (jackets, internal elements of helmets, covers, etc.).

[0108] The foam according to the invention has advantageous shock resistance, vibration resistance and sound insulation properties in combination with tactile properties suitable for capital goods. Therefore, the foam according to the invention can also be used to manufacture various parts in railway rail tie pads or in the automotive industry, in transportation, in electrical and electronic equipment, in construction or in the manufacturing industry.

[0109] According to an advantageous embodiment, the foam articles according to the invention can be easily recycled, for example, by melting them in an extruder equipped with a degassing outlet (after cutting them into pieces if necessary).

Examples

[0110] The following examples illustrate the invention without limiting it.

[0111] Example 1 Four types of PEBA were tested.

[0112] PEBA numbers 1, 2, and 3 are all PEBA copolymers containing a PA 11 block with a number average molecular weight of 600 g / mol and a PTMG block with a number average molecular weight of 1000 g / mol and a hardness of 32 Shore D. PEBA number 4 is a PEBA copolymer containing a PA 11 block with a number average molecular weight of 1500 g / mol, a PTMG block with a number average molecular weight of 2000 g / mol, and a Priplast™ 1838 polyester block with a number average molecular weight of 2000 g / mol.

[0113] PEBA number 1 is a linear PEBA. PEBA numbers 2, 3, and 4 are branched PEBA, and during their synthesis, 0.1 wt% trimethylolpropane (TMP), 0.15 wt% trimethylolpropane, and 0.1 wt% pentaerythritol (PET) are added respectively (relative to the total weight of the polyol and other reactants of the copolymer).

[0114] PEBA is prepared as indicated below.

[0115] PEBA number 1: Charge the autoclave with 13 kg of 11-aminoundecanoic acid, 3.8 kg of adipic acid, and 4 kg of water. Close the reactor, inertize with nitrogen, then stir and heat to 245 °C under spontaneous pressure. Maintain this temperature for 1 hour, with the pressure at 31 bar rel. Depressurize the reactor to atmospheric pressure over 1 hour. The material temperature is 240 °C. Add 26.1 kg of PTMG 1000, then place the reactor under a pressure of less than 15 mbar. Introduce 86 g of Irganox 1010, then 64 g of zirconium tetrabutoxide. Then monitor the thickening of the reaction medium by measuring the stirring torque. Stop the reaction when the torque reaches a predetermined value. Then transfer the reactor to a water tank and granulate.

[0116] PEBA number 2: PEBA number 2 is prepared in the same manner as PEBA number 1, except that 43 g of trimethylolpropane is also added to the loading.

[0117] PEBA 3: PEBA number 3 is prepared in the same manner as PEBA number 1, except that 3.9 kg of adipic acid is used instead of 3.8 kg, and 64 g of trimethylolpropane is also added to the loading.

[0118] PEBA number 4: PEBA number 4 is prepared in the same manner as PEBA number 1, except for the following: - The loading is as follows: 2 kg of adipic acid, 15.6 kg of 11-aminoundecanoic acid, 43 g of pentaerythritol, and 4 kg of water; - In the second step, 4 kg of PTMG 2000 and 21.4 kg of Priplast (trademark) 1838 are loaded; - Finally, 86 g of Irganox 1010 and 64 g of zirconium tetrabutoxide are added.

[0119] PEBA numbers 1 and 4 correspond to counterexamples, and PEBA numbers 2 and 3 are PEBA according to the present invention.

[0120] PEBA has the following properties: TIFF0007708665000002.tif50170

[0121] The weight average molecular weight Mw, number average molecular weight Mn, and z average molar mass Mz of PEBA are expressed as PMMA equivalents and are measured by size exclusion chromatography (or gel permeation chromatography) in accordance with ISO standard 16014-1 according to the above method.

[0122] The intrinsic viscosity is measured using an Ubbelohde tube. The measurement is carried out at 20 °C with 75 mg of the sample at a concentration of 0.5% (m / m) in m-cresol. The intrinsic viscosity is (g / 100g) -1It is represented by and calculated according to the following formula: Intrinsic viscosity = ln(t s / t0) × 1 / C, where C = m / p × 100, In the formula, t s is the flow time of the solution, t0 is the flow time of the solvent, m is the mass of the sample for determining the viscosity, and p is the mass of the solvent. This measurement conforms to ISO standard 307, apart from the fact that the measurement temperature is 20°C instead of 25°C.

[0123] The foams are prepared from PEBA numbers 1, 2, 3, and 4.

[0124] These foams are manufactured using an ENGEL 160T Victory injection molding machine equipped with a Trexel series II type physical foaming agent injection system. The operating parameters are as follows: - Barrel temperature: 190 - 210°C. - Holding time before mold opening: 17 - 28 seconds. - Cooling time: 120 - 180 seconds. - Mold temperature: 35 - 60°C. - Mold opening length: Up to 12 mm. - Mold: Plate mold with dimensions 2 × 100 × 100 mm.

[0125] The blowing agent used is dinitrogen, which is introduced at a ratio of 0.7% by weight.

[0126] Various properties of the obtained foams are evaluated: - Density: Conforms to ISO standard 845; - ΔDensity: Characterizes the uniformity of the foam and corresponds to the difference in density of the foamed part between the point closest to the injection point and the point farthest from the injection point; the lower this value, the more uniform the foam; - Rebound resilience: Conforms to ISO standard 8307 (a 16.8 g steel ball with a diameter of 16 mm is dropped onto the foam sample from a height of 500 mm; the rebound resilience then corresponds to the percentage of energy returned to the ball or the percentage of the initial height reached by the ball during rebound); - Compressive strain (comp. set): The measurement is performed by compressing the sample to a given degree of deformation and for a predetermined time, then releasing the applied stress, and recording the residual deformation after the recovery time; the measurement is compliant with ISO standard 7214 and is carried out 30 minutes later under the conditions of 50% deformation, a holding time of 22 hours, and a temperature of 23 °C.

[0127] The properties of the foams are presented in the following table: TIFF0007708665000003.tif70170

[0128] Various densities for the same PEBA are obtained by changing the parameters of the foam manufacturing method. The densities of foams C and D correspond to the minimum densities achieved with PEBA numbers 1 and 2, respectively.

[0129] It is observed that the foam of PEBA number 2 (foam D) has a lower minimum density than the foam formed from PEBA number 1 (foam C). Furthermore, foam D is more uniform and has a lower compressive strain after 30 minutes than foam C, while having a similar resilience.

[0130] Furthermore, by comparing foam B (of PEBA number 1) and foam F (of PEBA number 3), it is observed that at the same density, foam F has a lower compressive strain after 30 minutes than that of foam B.

[0131] It was not possible to obtain a foam from PEBA number 4.

Claims

1. A foam of a branched copolymer containing a rigid block and a flexible block, wherein the branches are made by polyol residues that link the rigid blocks of the copolymer, said polyol being a polyol containing at least three hydroxyl groups, said copolymer being selected from copolymers containing a polyester block and a polyether block (COPEs), copolymers containing a polyurethane block and a polyether block (TPUs), or copolymers containing a polyamide block and a polyether block (PEBAs), said copolymer having a weight average molecular weight Mw of 80,000 g / mol or more, and the ratio of the weight average molecular weight Mw of the copolymer to the number average molecular weight Mn of the copolymer being 2.2 or more, a foam.

2. The foam according to claim 1, wherein the copolymer has a weight average molecular weight Mw in the range of 80,000 to 300,000 g / mol.

3. The foam according to claim 1 or 2, wherein the ratio of the weight average molecular weight Mw of the copolymer to the number average molecular weight Mn of the copolymer is 2.4 or more.

4. The foam according to any one of claims 1 to 3, wherein the ratio of the z average molar mass Mz of the copolymer to the weight average molecular weight Mw of the copolymer is 1.8 or more.

5. The foam according to any one of claims 1 to 4, wherein the copolymer contains a polyamide block and a polyether block.

6. The polyamide block is a block of polyamide 6, polyamide 11, polyamide 12, polyamide 5.4, polyamide 5.9, polyamide 5.10, polyamide 5.12, polyamide 5.13, polyamide 5.14, polyamide 5.16, polyamide 5.18, polyamide 5.36, polyamide 6.4, polyamide 6.9, polyamide 6.10, polyamide 6.12, polyamide 6.13, polyamide 6.14, polyamide 6.16, polyamide 6.18, polyamide 6.36, polyamide 10.4, polyamide 10.9, polyamide 10.10, polyamide 10.12, polyamide 10.13, polyamide 10.14, polyamide 10.16, polyamide 10.18, polyamide 10.36, polyamide 10.T, polyamide 12.4, polyamide 12.9, polyamide 12.10, polyamide 12.12, polyamide 12.13, polyamide 12.14, polyamide 12.16, polyamide 12.18, polyamide 12.36, polyamide 12.T or a mixture thereof, or a copolymer thereof, the foam according to claim 5.

7. The polyether block is a block of polyethylene glycol, propylene glycol, polytetramethylene glycol, polytetrahydrofuran, or a mixture thereof, or a copolymer thereof, the foam according to claim 5 or 6.

8. - The rigid block of the copolymer has a number average molecular weight of 400 to 20,000 g / mol, and / or - The flexible block of the copolymer has a number average molecular weight of 100 to 6000 g / mol, The foam according to any one of claims 1 to 7.

9. The mass ratio of the rigid block of the copolymer to the flexible block is 0.1 to 20, the foam according to any one of claims 1 to 8.

10. The polyol has a weight average molecular weight of 3000 g / mol or less, the foam according to any one of claims 1 to 9.

11. The polyol is selected from pentaerythritol, trimethylolpropane, trimethylolethane, hexanetriol, diglycerol, methyl glucoside, sorbitol, dipentaerythritol, cyclodextrin, polyether polyols containing at least three hydroxyl groups, and mixtures thereof, the foam according to any one of claims 1 to 10.

12. 800 kg / m ３ The foam according to any one of claims 1 to 11, having the following density.

13. The foam according to any one of claims 1 to 12, having a compression strain after 30 minutes of 35% or less.

14. The following steps: - Optionally mixing the copolymer in a molten state with one or more additives and a blowing agent; and - Foaming the mixture of the copolymer and the blowing agent, The method for producing a foam according to any one of claims 1 to 13, comprising.

15. An article made of the foam according to any one of claims 1 to 13.

16. An article comprising at least one element made of the foam according to any one of claims 1 to 13.

17. The article according to claim 15 or 16, selected from the sole of a sports shoe, a large or small ball, a glove, personal protective equipment, a rail tie pad, automotive parts, construction parts, and electrical and electronic equipment parts.

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