Method for producing copolymer foams containing polyamide blocks and polyether blocks

Abstract

The present invention provides a method for producing a copolymer foam containing polyamide blocks and polyether blocks, which enables the production of a high-quality, extremely low-density foam that is also recyclable. [Solution] The present invention relates to a method for producing a copolymer foam containing polyamide blocks and polyether blocks, comprising the steps of: - mixing a foaming agent with a copolymer in a molten state; and - foaming the mixture of the copolymer and the foaming agent, wherein the foaming agent comprises a mixture of dinitrogen and carbon dioxide. The present invention also relates to a copolymer foam containing polyamide blocks and polyether blocks that can be obtained by such a production method.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a copolymer foam containing a polyamide block and a polyether block. [Background technology]

[0002] Various polymer foams are used in the field of sports equipment, such as shoe soles or sole components, gloves, rackets or golf balls, and especially in personal protective items for sports (jackets, helmet linings, covers, etc.). For example, copolymer foams (or PEBA foams) containing polyamide blocks and polyether blocks are particularly suitable for these applications.

[0003] Such applications require a set of specific physical properties to ensure resilience, low compressive strain, and the ability to withstand repeated impacts without deformation and to recover to their original shape.

[0004] Reference FR 3047245 describes a PEBA foam obtained by injection molding using dinitrogen as a foaming agent. Such a foam can have a relatively low density. However, in some applications, it may be desirable to obtain a foam with an even lower density.

[0005] References EP 0405227 and EP 0402883 describe the use of foams and shoe soles made from various polymers.

[0006] Reference EP 1650255 describes a crosslinked foam obtained from a copolymer containing polyamide blocks and polyether blocks.

[0007] Cross-linked foams have the disadvantage of being highly constrained from a manufacturing method standpoint: manufacturing time is generally long, manufacturing is generally only possible in batch mode, and undesirable chemical products must be handled.

[0008] In addition, cross-linked foams are difficult to recycle after use.

[0009] Reference WO 2013 / 148841 describes a two-layer extrusion method using various polymers, including copolymers containing polyamide blocks and polyether blocks.

[0010] Reference WO 2015 / 052265 describes a method for producing foamed thermoplastic resin particles using any elastomeric thermoplastic polymer.

[0011] Reference US 2015 / 0174808 describes a method for producing foamed polymer pellets, particularly polyurethane pellets.

[0012] Kin Lin's paper, "Development of high strength microcellular foams using polyether block amide," published in 2010 in the Department of Mechanical & Industrial Engineering at the University of Toronto, describes PEBA foam or PEBA mixed foam obtained by a batch method using carbon dioxide.

[0013] Reference GB 2296014 relates to a golf ball having a core made of a thermoplastic polymer foam, such as a polyamide or polyether polyamide copolymer.

[0014] Reference US 2005 / 0049545 describes a method for manufacturing a medical device in which a second polymeric material is overmolded onto a first polymeric material, and the second polymeric material is converted into a foam.

[0015] Reference JP 2005350574 describes a foam of thermoplastic polymer manufactured using an inert gas (carbon dioxide or dinitrogen).

[0016] Furthermore, Zotefoams markets a cross-linked foam made from a copolymer containing polyamide blocks and polyether blocks under the name Zotek® PEBA. The drawbacks of cross-linking were recalled above. Furthermore, the durability of the product is not ideal.

[0017] Dinitrogen or carbon dioxide has been conventionally used during the production of polymer foams, particularly in the injection molding process. However, in the case of PEBA foams, these blowing agents have certain drawbacks.

[0018] There is a genuine need to provide a method for producing a copolymer foam containing polyamide blocks and polyether blocks that enables the production of a very low density foam of good quality that is also recyclable. Summary of the Invention

[0019] The present invention first provides a method for producing a copolymer foam containing polyamide blocks and polyether blocks, the method comprising the following steps: - mixing a blowing agent with a copolymer in a molten state; - foaming the mixture of the copolymer and the blowing agent wherein the blowing agent comprises a mixture of dinitrogen and carbon dioxide. The present invention relates to such a method.

[0020] According to an embodiment, the present invention provides a method for producing a copolymer foam containing polyamide blocks and polyether blocks, the method comprising the following steps: - mixing a blowing agent with a copolymer in a molten state; - foaming the mixture of the copolymer and the blowing agent wherein the blowing agent comprises a mixture of dinitrogen and carbon dioxide, and the method is an injection molding method. The present invention relates to such a method.

[0021] ​​According to one embodiment, the blowing agent comprises 20% to 95% by weight, preferably 40% to 95% by weight, of dinitrogen and 5% to 80% by weight, preferably 5% to 60% by weight, of carbon dioxide.

[0022] According to the embodiment, the polyamide block of the copolymer has a number-average molecular weight of 400 to 20,000 g / mol, preferably 500 to 10,000 g / mol.

[0023] According to the embodiment, the polyether block of the copolymer has a number-average molecular weight of 100 to 6000 g / mol, preferably 200 to 3000 g / mol.

[0024] According to the embodiment, the mass ratio of the copolymer polyamide block to the polyether block is 0.1 to 20, preferably 0.3 to 3, and more preferably 0.3 to 0.9.

[0025] According to the embodiment, the copolymer polyamide block is made up 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, and polyamide 10.10. The polyamides are blocks or mixtures thereof of 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 copolymers thereof, preferably blocks of polyamide 11, polyamide 12, polyamide 6, or polyamide 6.10.

[0026] According to the embodiment, the polyether block is a block of polyethylene glycol, propylene glycol, polytrimethylene glycol, polytetrahydrofuran, or a mixture or copolymer thereof, preferably a block of polyethylene glycol or polytetrahydrofuran.

[0027] According to the embodiment, the foam is 0.8 g / cm³ 3 The following densities, preferably 0.05 to 0.8 g / cm³ 3 More preferably 0.08~0.5g / cm³ 3 And, even more preferentially, 0.08~0.3g / cm³ 3 It has a density of .

[0028] According to the embodiment, the foam is non-crosslinked.

[0029] According to embodiments, the method of the present invention includes the step of injecting a mixture of copolymer and foaming agent into a mold, and foaming of the mixture is performed by opening the mold.

[0030] According to the embodiment, the blowing agent is present in the mixture of the copolymer and the blowing agent in an amount of 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.2% to 1.5%, relative to the total weight of the blowing agent and the copolymer containing the polyamide block and the polyether block.

[0031] According to embodiments, the method of the present invention comprises mixing a molten copolymer with one or more additives, preferably selected from ethylene and vinyl acetate copolymers, ethylene and acrylate copolymers, and ethylene and alkyl (meth)acrylate copolymers, and a foaming agent.

[0032] The present invention also relates to a copolymer foam containing a polyamide block and a polyether block, which can be obtained by the above-described manufacturing method.

[0033] According to the embodiment, the foam is 0.8 g / cm³ 3 The following densities, preferably 0.05 to 0.8 g / cm³ 3 More preferably 0.08~0.5g / cm³ 3 And, even more preferentially, 0.08~0.3g / cm³ 3 It has a density of .

[0034] According to the embodiment, the foam has an expansion rate in the range of 2 to 25, preferably 3 to 20, and more preferably 4 to 15.

[0035] The present invention satisfies the needs specified above. More specifically, the present invention provides a method for producing a copolymer foam containing a polyamide block and a polyether block, which enables obtaining a foam that is simultaneously recyclable, low-density or even extremely low-density, and has good mechanical properties, such as good strength.

[0036] This is achieved by using a specific blowing agent containing a mixture of dinitrogen and carbon dioxide to induce foaming of the copolymer.

[0037] In fact, using dinitrogen or carbon dioxide alone in the production of PEBA foam has certain drawbacks.

[0038] Therefore, the presence of dinitrogen causes weak expansion, making it impossible to achieve the extremely low density value of the foam.

[0039] Using carbon dioxide as a blowing agent leads to the creation of a vacuum inside the PEBA foam due to the very rapid diffusion of carbon dioxide to the outside of the foam. This causes the foam to collapse on its own and become unusable. [Brief explanation of the drawing]

[0040] [Figure 1] This is a scanning electron microscope (SEM) image of the alveolar structure of foam No. 1, obtained according to the method described in Example 1, using a mixture of 75% by weight of dinitrogen and 25% by weight of carbon dioxide as a blowing agent introduced in an amount of 1% by weight. [Figure 2] This is an SEM image of the alveolar structure of foam No. 2, obtained according to the method described in Example 1, using a mixture of 75% by weight of dinitrogen and 25% by weight of carbon dioxide as a blowing agent, introduced in an amount of 1.2% by weight. [Figure 3] This is an SEM image of the alveolar structure of foam No. 3, obtained according to the method described in Example 1, using dinitrogen introduced in an amount of 0.6 wt% as a foaming agent. [Figure 4] This is an SEM image of the alveolar structure of foam No. 4, obtained according to the method described in Example 1, using dinitrogen introduced in an amount of 0.8 wt% as a foaming agent. [Figure 5] This is an image of foam No. 2 obtained according to the method described in Example 1, using a mixture of 75% by weight of dinitrogen and 25% by weight of carbon dioxide as a blowing agent, introduced in an amount of 1.2% by weight. [Figure 6] This is an image of foam No. 3, obtained according to the method described in Example 1, using dinitrogen introduced in an amount of 0.6% by weight as a blowing agent. [Figure 7] This is an image of foam No. 5, obtained using carbon dioxide as a blowing agent introduced in an amount of 6-8% by weight, according to the method described in Example 1. [Modes for carrying out the invention]

[0041] Next, the present invention will be described in more detail and non-limiting terms in the following description.

[0042] Unless otherwise specified, all percentages are mass percentages.

[0043] The present invention relates to a method for producing a copolymer foam containing a polyamide block and a polyether block (or PEBA).

[0044] PEBA is derived from the polycondensation of a polyamide block with a polyether block with a reactive end, for example, in particular: 1) Polyoxyalkylene blocks with dicarboxyl chain ends and polyamide blocks with diamine chain ends; 2) Polyamide blocks having dicarboxyl chain ends and polyoxyalkylene blocks having diamine chain ends, for example, obtained by cyanoethylation and hydrogenation of α,ω-dihydroxylated aliphatic polyoxyalkylene blocks known as polyetherdiols; 3) The product obtained is, in that particular case, a polyether ester amide, a polyamide block having a dicarboxyl chain end with a polyether diol, It is produced by polycondensation.

[0045] Polyamide blocks with dicarboxyl chain ends are derived, for example, from the condensation of polyamide precursors in the presence of chain-restricting dicarboxylic acids. Polyamide blocks with diamine chain ends are derived, for example, from the condensation of polyamide precursors in the presence of chain-restricting diamines.

[0046] Three types of polyamide blocks can be used advantageously.

[0047] According to the first type, the polyamide block is derived from the condensation of a dicarboxylic acid, particularly one containing 4 to 20 carbon atoms, preferably one containing 6 to 18 carbon atoms, and an aliphatic or aromatic diamine, particularly one containing 2 to 20 carbon atoms, preferably one containing 6 to 14 carbon atoms.

[0048] Examples of dicarboxylic acids include 1,4-cyclohexanedicarboxylic acid, butanediic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, terephthalic acid and isophthalic acid, and dimerized fatty acids.

[0049] 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-aminodicyclohexylmethane (PACM), isophoronediamine (IPDA), 2,6-bis(aminomethyl)norbornane (BAMN), and piperazine (Pip).

[0050] 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 PA XY notation, 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.

[0051] 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 diamine containing 4 to 12 carbon atoms. Examples of lactams include caprolactam, oenantractam, and lauryllactam. Examples of α,ω-aminocarboxylic acids include aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0052] Advantageously, the second type of polyamide block is PA 11 (polyundecaneamide), PA 12 (polydodecaneamide), or PA 6 (polycaprolactam). In the notation PA X, X represents the number of carbon atoms derived from an amino acid residue.

[0053] 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.

[0054] In this case, the polyamide PA block is: - A linear aliphatic or aromatic diamine containing X carbon atoms; - Dicarboxylic acids containing Y carbon atoms; and - Comonomer {Z} selected from lactams and α,ω-aminocarboxylic acids containing Z carbon atoms, and an equimolar mixture of at least one diamine containing X1 carbon atoms and at least one dicarboxylic acid containing Y1 carbon atoms, where (X1, Y1) is different from (X, Y). It is a polycondensation, - The comonomer {Z} is introduced in a weight proportion of up to 50%, preferably up to 20%, and more preferably up to 10%, relative to the total amount of the polyamide precursor monomer; - In the presence of a chain limiting agent selected from dicarboxylic acids, It is prepared by polycondensation.

[0055] Advantageously, a dicarboxylic acid containing Y carbon atoms is used as a chain limiting agent, which is introduced in excess of the diamine's stoichiometry.

[0056] According to one variant of this third type, polyamide blocks are produced from the condensation of at least two α,ω-aminocarboxylic acids containing 6 to 12 carbon atoms, or from the condensation of at least two lactams, or from the condensation of one lactam and one aminocarboxylic acid having less than the same number of carbon atoms, in the presence of a chain limiting agent as needed. 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, oenantractam, and lauryllactam. Examples of aliphatic diamines include hexamethylenediamine, dodecamethylenediamine, and trimethylhexamethylenediamine. An example of an alicyclic diacid is 1,4-cyclohexanedicarboxylic acid. Examples of aliphatic diacids include butanediic 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%; they are preferably hydrogenated; they are products marketed, for example, by Croda under the brand name Pripol, by BASF under the brand name Empol, or by Oleon under the brand name Radiacid, 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 may include isophoronediamine (IPDA), 2,6-bis(aminomethyl)norbornane (BAMN), and piperazine.

[0057] Examples of the third type of polyamide block include: - PA 6.6 / 6, where 6.6 represents the hexamethylenediamine unit condensed with adipic acid, and 6 represents the unit 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 sebaciic acid, 11 represents the unit produced from the condensation of aminoundecanoic acid, and 12 represents the unit produced from the condensation of lauryl lactam.

[0058] The notations PA X / Y, PA X / Y / Z, etc., relate to copolyamides, where X, Y, Z, etc., represent the homopolyamide units mentioned above.

[0059] Advantageously, the polyamide blocks of copolymers used in this invention include polyamides PA6, PA11, PA12, PA5.4, PA5.9, PA5.10, PA5.12, PA5.13, PA5.14, PA5.16, PA5.18, PA5.36, PA6.4, PA6.9, PA6.10, PA6.12, PA6.13, PA6.14, PA6.16, PA6.18, PA6.36, PA10.4, PA10.9, PA10.10, PA10.12, PA10.13, PA10.14, PA10.16, PA10.18, PA10.36, PA10.T, PA12.4, PA12.9, PA It comprises blocks of 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, it comprises blocks of polyamide PA 6, PA 11, PA 12, PA 6.10, PA 10.10, or PA 10.12, or mixtures or copolymers thereof.

[0060] Polyether blocks are formed from alkylene oxide units.

[0061] Polyether blocks can be, in particular, PEG (polyethylene glycol) blocks, i.e., blocks formed from ethylene oxide units, and / or PPG (propylene glycol) blocks, i.e., blocks formed from propylene oxide units, and / or PO3G (polytrimethylene glycol) blocks, i.e., blocks formed from polytrimethylene glycol ether units, and / or PTMG blocks, i.e., blocks formed from tetramethylene glycol units, also known as polytetrahydrofuran. PEBA copolymers can contain several types of polyethers in their chains, and the copolyethers may be in block form or statistical form.

[0062] Blocks obtained by oxyethylation of bisphenols, such as bisphenol A, can also be used. The latter product is described in particular in reference EP 613 919.

[0063] Polyether blocks can also be formed from ethoxylated primary amines. An example of an ethoxylated primary amine is given by formula: Examples of products include those listed in TIFF2026053369000002.tif38170 [wherein m and n are integers between 1 and 20, and x is an integer between 8 and 18]. These products are marketed, for example, by CECA under the brand name Noramox® and by Clariant under the brand name Genamin®.

[0064] Flexible polyether blocks may include polyoxyalkylene blocks having NH2 chain ends, which can be obtained by cyanoacetylation of α,ω-dihydroxylated aliphatic polyoxyalkylene blocks, referred to as polyetherdiols. More specifically, commercially available products Jeffamine or Elastamine can be used (e.g., the commercially available products Jeffamine® D400, D2000, ED 2003, XTJ 542 from Huntsman, also described in JP 2004 / 346274, JP 2004 / 352794 and EP 1482011).

[0065] Polyetherdiol blocks are used in their unmodified form and are either copolymerized with polyamide blocks having carboxyl-terminated groups, or aminated to polyetherdiamines and then condensed with polyamide blocks having carboxyl-terminated groups. A general two-step method for preparing PEBA copolymers containing an ester bond between the PA and PE blocks is known, for example, described in reference FR 2846332. A general method for preparing PEBA copolymers having an amide bond between the PA and PE blocks is also known, for example, described in reference EP 1482011. Polyether blocks can also be mixed with polyamide precursors and chain-limiting diacitors to prepare polymers containing polyamide and polyether blocks with randomly distributed units (one-step method).

[0066] Needless to say, the term PEBA in this description of the present invention is not limited to Pebax® products sold by Arkema, Vestamid® products sold by Evonik®, and Grilamid® products sold by EMS, but also includes Pelestat® type PEBA products sold by Sanyo and any other PEBA from other suppliers.

[0067] While the block copolymers described above generally comprise at least one polyamide block and at least one polyether block, the present invention also covers all copolymer alloys comprising two, three, four (or more) different blocks selected from those described herein, provided that these blocks comprise at least one polyamide block and one polyether block.

[0068] For example, the copolymer alloy according to the present invention may include a segmented block copolymer (or "triblock" copolymer) comprising three different types of blocks, which is produced from the condensation of some of the above blocks. The triblock copolymer is preferably selected from copolyether ester amides and copolyether amide urethanes.

[0069] In the context of the present invention, a particularly preferred PEBA copolymer is a copolymer comprising blocks from 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.

[0070] The number-average molecular weight of the polyamide blocks in the PEBA copolymer is preferably 400 to 20,000 g / mol, more preferably 500 to 10,000 g / mol. In certain embodiments, the number-average molecular weight of the polyamide blocks in the PEBA copolymer is 400 to 500 g / mol, or 500 to 600 g / mol, or 600 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. 0.1000 g / mol, or 8000-9000 g / mol, or 9000-10,000 g / mol, or 10,000-11,000 g / mol, or 11,000-12,000 g / mol, or 12,000-13,000 g / mol, or 13,000-14,000 g / mol, or 14,000-15,000 g / mol, or 15,000-16,000 g / mol, or 16,000-17,000 g / mol, or 17,000-18,000 g / mol, or 18,000-19,000 g / mol, or 19,000-20,000 g / mol.

[0071] The number-average molecular weight of the polyether 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 polyether 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.

[0072] The number average molecular weight is set by the content of the chain terminator. This is according to the equation: M n =n monomer ×MW repeating unit / n chain limiter +MW chain limiter and can be calculated according to

[0073] In this formula, n monomer represents the number of moles of the monomer, n chain limiter represents the number of moles of the excess diacid terminator, MW repeating unit represents the molar mass of the repeating unit, MW chain limiter represents the molar mass of the excess diacid.

[0074] The number average molecular weights of the polyamide block and the polyether block can be measured by gel permeation chromatography (GPC) in accordance with ISO standard 16014-1:2012 before the copolymerization of both blocks.

[0075] Advantageously, the mass ratio of the copolymer polyamide block to the polyether block is 0.1 to 20, preferably 0.3 to 3, and more preferably 0.3 to 0.9. This weight ratio can be calculated by dividing the number-average molecular weight of the polyamide block by the number-average molecular weight of the polyether block. Specifically, the mass ratio of the copolymer polyamide block to the polyether block is 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, and so on. Alternatively, it can be 4.5-5, or 5-5.5, or 5.5-6, or 6-6.5, or 6.5-7, or 7-7.5, or 7.5-8, or 8-8.5, or 8.5-9, or 9-9.5, or 9.5-10, or 10-11, or 11-12, or 12-13, or 13-14, or 14-15, or 15-16, or 16-17, or 17-18, or 18-19, or 19-20.

[0076] Preferably, the copolymer used in the present invention has an instantaneous hardness of 40 Shore D or less, more preferably 35 Shore D or less. Hardness measurement can be performed in accordance with ISO standard 868:2003.

[0077] Copolymers containing polyamide blocks and polyether blocks are used to form a foam, preferably without a crosslinking step. The foam is formed by mixing a foaming agent (also called a foaming agent) with a molten copolymer, followed by a foaming step.

[0078] The blowing agent contains a mixture of dinitrogen and carbon dioxide. Preferably, the blowing agent is essentially composed of or consists of a mixture of dinitrogen and carbon dioxide.

[0079] Dinitrogen has high nucleation ability but low expansion ability. Carbon dioxide has high expansion ability but low nucleation ability. Combining dinitrogen and carbon dioxide creates a synergistic effect, making it possible to obtain a blowing agent that exhibits both high nucleation ability and high expansion ability.

[0080] Advantageously, the blowing agent contains, or is essentially composed of, 20% to 95% by weight, preferably 40% to 95% by weight, of dinitrogen and 5% to 80% by weight, preferably 5% to 60% by weight, of carbon dioxide. In embodiments, the blowing agent may contain 1% to 5% by weight of dinitrogen and 95% to 99% by weight of carbon dioxide, or 5% to 10% by weight of dinitrogen and 90% to 95% by weight of carbon dioxide, or 10% to 15% by weight of dinitrogen and 85% to 90% by weight of carbon dioxide, or 15% to 20% by weight of dinitrogen and 80% to 85% by weight of carbon dioxide, or 20% to 25% by weight of dinitrogen and 75% to 80% by weight of carbon dioxide, and This is 25% to 30% by weight of dinitrogen and 70% to 75% by weight of carbon dioxide, or 30% to 35% by weight of dinitrogen and 65% to 70% by weight of carbon dioxide, or 35% to 40% by weight of dinitrogen and 60% to 65% by weight of carbon dioxide, or 40% to 45% by weight of dinitrogen and 55% to 60% by weight of carbon dioxide, or 45% to 50% by weight of dinitrogen and 50% to 55% by weight of carbon dioxide, or 50% to 55 A mixture of 1% by weight dinitrogen and 45% to 50% by weight carbon dioxide, or 55% to 60% by weight dinitrogen and 40% to 45% by weight carbon dioxide, or 60% to 65% by weight dinitrogen and 35% to 40% by weight carbon dioxide, or 65% to 70% by weight dinitrogen and 30% to 35% by weight carbon dioxide, or 70% to 75% by weight dinitrogen and 25% to 30% by weight carbon dioxide, or 75% to 80% by weight dinitrogen and It contains, essentially consists of, or comprises 20% to 25% by weight of carbon dioxide, or 80% to 85% by weight of dinitrogen and 15% to 20% by weight of carbon dioxide, or 85% to 90% by weight of dinitrogen and 10% to 15% by weight of carbon dioxide, or 90% to 95% by weight of dinitrogen and 5% to 10% by weight of carbon dioxide, or 95% to 99% by weight of dinitrogen and 1% to 5% by weight of carbon dioxide.

[0081] The foaming agent is mixed with the copolymer in liquid or supercritical form and then converted to a gas phase during the foaming process.

[0082] The blowing agent is preferably present in the mixture in an amount of 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.2% to 1.5% by mass, relative to the total weight of the blowing agent and the copolymer containing the polyamide block and the polyether block. In particular, the blowing agent may be present in an amount of mass of 0.1% to 0.2%, or 0.2% to 0.4%, or 0.4% to 0.6%, or 0.6% to 0.8%, or 0.8% 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 6%, or 6% to 7%, or 7% to 8%, or 8% to 9%, or 9% to 10%, relative to the total weight of the blowing agent and the copolymer containing the polyamide block and the polyether block.

[0083] The foam obtained by the method according to the present invention comprises the above-mentioned PEBA copolymer; preferably, only one such copolymer is used. However, it is possible to use a mixture of two or more of the above-mentioned PEBA copolymers.

[0084] Copolymers containing polyamide blocks and polyether blocks can be combined with various additives, such as copolymers of ethylene and vinyl acetate or EVA (e.g., sold by Arkema under the name Evatane®), or copolymers of ethylene and acrylate, or copolymers of ethylene and alkyl (meth)acrylate, e.g., sold by Arkema under the name Lotryl®. These additives allow for adjustment of the hardness, appearance, and comfort of the foamed components. Additives can be added to the copolymer containing polyamide blocks and polyether blocks in a content of 0 to 50% by mass, preferably 5% to 30% by mass.

[0085] The method for producing the foam according to the present invention is preferably an injection molding method. This technique allows for the direct production of three-dimensional foamed articles with complex shapes. Preferably, foaming is performed by injecting a mixture of copolymer and foaming agent into a mold and opening the mold.

[0086] The method for producing foam according to the present invention is also a relatively simple technique to perform, compared in particular to certain methods for melting foam particles described in the prior art: In detail, filling a mold with foam 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.

[0087] Other foaming techniques that can be used (though less preferably) include, in particular, batch foaming and extrusion foaming.

[0088] According to the embodiment, the foam thus formed is essentially made from or entirely from the copolymer (or, if a mixture of copolymers is used, multiple copolymers) and, if the blowing agent remains present in the pores of the foam, and especially if the foam is a foam having isolated pores.

[0089] The foam produced according to the present invention may contain a mixture of dinitrogen and carbon dioxide, especially if it is an isolated-porous foam.

[0090] The foam produced according to the present invention preferably has a concentration of 0.8 g / cm³. 3 It has the following densities. Preferably, the density of the foam is 0.05 to 0.8 g / cm³. 3 More preferably 0.08~0.5g / cm³ 3 And, even more preferentially, 0.08~0.3g / cm³ 3 According to the embodiment, the foam is 0.05 to 0.08 g / cm³. 3 , or 0.08~0.1 g / cm³ 3, or 0.1~0.12 g / cm³ 3 , or 0.12~0.15 g / cm³ 3 , or 0.15~0.18 g / cm³ 3 , or 0.18~0.2 g / cm³ 3 , or 0.2~0.3 g / cm³ 3 , or 0.3~0.4 g / cm³ 3 , or 0.4~0.5 g / cm³ 3 , or 0.5~0.6 g / cm³ 3 , or 0.6~0.7 g / cm³ 3 , or 0.7~0.8 g / cm³ 3 It has a density of [density]. The density can be controlled by adapting the parameters of the manufacturing method. The density can be measured in accordance with ISO standard 845:2006.

[0091] Advantageously, the foam has an expansion coefficient in the range of 2 to 25, preferably 3 to 20, and more preferably 4 to 15. The expansion coefficient corresponds to the ratio of the volume of the foam to the volume of the polymer, and is particularly expressed by formula: Expansion rate = Polymer density / Foam density It is calculated according to the following. Preferably, the foam has an expansion rate in the range of 2-3, or 3-4, or 4-5, or 5-6, or 6-7, or 7-8, or 8-9, or 9-10, or 10-11, or 11-12, or 12-13, or 13-14, or 14-15, or 15-16, or 16-17, or 17-18, or 18-19, or 19-20, or 20-21, or 21-22, or 22-23, or 23-24, or 24-25.

[0092] Particularly preferable, the foam is not crosslinked.

[0093] Preferably, the foam has a rebound elasticity of 55% or more in accordance with ISO standard 8307:2007.

[0094] Preferably, the foam has a compressive strain of 10% or less, and more preferably 8% or less, in accordance with ISO standard 7214:2012.

[0095] Preferably, the foam also has excellent characteristics in terms of fatigue strength and damping.

[0096] The foam according to the present invention can be used to manufacture sports equipment, for example, components of athletic shoe soles, ski shoes, midsoles, insoles, or functional soles in the form of inserts in various parts of the sole (e.g., heels and arches), or components of the upper part of the shoe in the form of reinforcements, inserts, or protective materials.

[0097] The foam according to the present invention can also be used to manufacture inflatable balls, sports gloves (e.g., soccer gloves), golf ball components, rackets, and protective elements (jackets, helmet inner elements, covers, etc.).

[0098] The foam according to the present invention has advantageous impact resistance, vibration resistance, and noise resistance, combined with tactile properties suitable for equipment. Therefore, the foam according to the present invention can also be used to manufacture railway rail soles, or various components in the automotive industry, transportation, electrical and electronic equipment, construction, or manufacturing industries.

[0099] One advantage of the foam articles according to the present invention is that they can be easily recycled, for example, by melting them in an extruder equipped with a degassing vent (after cutting them into pieces as necessary). [Examples]

[0100] The following examples illustrate the present invention without limiting it.

[0101] Example 1 Two foams are prepared from a PEBA copolymer 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.

[0102] The foam formed from the PEBA copolymer is manufactured using an Arburg Allrounder 270C injection molding machine equipped with a Trexel Series II type physical blowing agent injection system. The operating parameters are as follows: - Sheath temperature: 50-230°C (from feed hopper to injector nozzle); the temperature of the injected mixture can be approximated to the sheath temperature at the injector nozzle; - Injection speed: 80cm 3 / sec; - Holding time before mold opening: 30 seconds; - Maintaining pressure: 150 MPa; - Cooling time: 100 seconds; - Mold temperature: 60℃; - Mold opening speed: 20mm / s; - Mold thickness: 3mm; - Mold opening distance: 12mm.

[0103] The mold opening distance is defined as the maximum distance at which the mold can be opened while obtaining a foam of good quality.

[0104] The blowing agent used is a mixture of 75% by weight of dinitrogen and 25% by weight of carbon dioxide, and is introduced in an amount of 1% by weight (foam number 1) or 1.2% by weight (foam number 2).

[0105] In addition, the three comparative foams are prepared from the same copolymer and according to the same procedure, except that the blowing agent is either dinitrogen introduced in an amount of 0.6% by weight (foam number 3) or 0.8% by weight (foam number 4), or carbon dioxide introduced in an amount of 6-8% by weight (foam number 5).

[0106] The density of various foams will be measured in accordance with ISO standard 845.

[0107] The expansion rate is defined as the ratio of the volume of the foam to the volume of the polymer, and is specifically given by the formula: Expansion rate = Polymer density / Foam density It is calculated according to

[0108] Images of the obtained foam are shown in Figures 1 to 7.

[0109] Foams No. 1 and 2 (manufactured according to the present invention) have a density of approximately 0.14 g / cm³. 3 and has an expansion coefficient of 7.

[0110] Foams No. 3 and 4 (comparative examples) have a density of approximately 0.2 g / cm³. 3 and has an expansion ratio of 5.

[0111] Foam No. 5 (comparative example) disintegrated on its own.

[0112] The rebound elasticity was measured in accordance with ISO standard 8307 (a 16.8g steel ball with a diameter of 16mm was dropped onto a foam sample from a height of 500mm; rebound elasticity then corresponds to the percentage of energy returned to the ball, or the percentage of the initial height the ball reached upon rebound).

[0113] The results are shown in the table below: TIFF2026053369000003.tif49170

Claims

1. The following steps: - Mixing a foaming agent with a copolymer in a molten state; - Foaming a mixture of copolymer and foaming agent A method for producing a copolymer foam containing a polyamide block and a polyether block, The blowing agent contains a mixture of dinitrogen and carbon dioxide. method.

2. The method according to claim 1, wherein the blowing agent comprises 20% to 95% by weight, preferably 40% to 95% by weight, of dinitrogen and 5% to 80% by weight, preferably 5% to 60% by weight, of carbon dioxide.

3. The method according to claim 1 or 2, wherein the polymer polyamide block has a number-average molecular weight of 600 to 5000 g / mol, preferably 600 to 4000 g / mol.

4. The method according to any one of claims 1 to 3, wherein the copolymer polyether block has a number average molecular weight of 250 to 2000 g / mol, preferably 650 to 2000 g / mol.

5. The method according to any one of claims 1 to 4, wherein the mass ratio of the copolymer polyamide block to the polyether block is 0.3 to 10, preferably 0.3 to 3.

6. The copolymer polyamide blocks are 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 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. The method according to any one of claims 1 to 5, wherein the blocks are of T or mixtures thereof, or copolymers thereof, preferably blocks of polyamide 11, polyamide 12, polyamide 6, or polyamide 6.

10.

7. The method according to any one of claims 1 to 6, wherein the polyether block is a block of polyethylene glycol, propylene glycol, polytrimethylene glycol, polytetrahydrofuran, or a mixture or copolymer thereof, preferably a block of polyethylene glycol or polytetrahydrofuran.

8. The foam contains 0.8 g / cm³ of foam. ３ The following densities, preferably 0.05 to 0.8 g / cm³ ３ More preferably 0.08–0.5 g / cm³ ３ And, more preferably, 0.08 to 0.3 g / cm³ ３ The method according to any one of claims 1 to 7, having the density of

9. The method according to any one of claims 1 to 8, wherein the foam is non-crosslinked.

10. The method according to any one of claims 1 to 9, comprising the step of pouring a mixture of copolymer and a foaming agent into a mold, wherein foaming of the mixture is performed by opening the mold.

11. The method according to any one of claims 1 to 10, wherein the blowing agent is present in a mixture of the copolymer and the blowing agent in an amount of 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.2% to 1.5% by mass, relative to the total weight of the blowing agent and the copolymer containing the polyamide block and the polyether block.

12. The method according to any one of claims 1 to 11, comprising mixing a molten copolymer with one or more additives, preferably selected from ethylene and vinyl acetate copolymers, ethylene and acrylate copolymers, and ethylene and alkyl (meth)acrylate copolymers, and a blowing agent.

13. The method according to any one of claims 1 to 12, which is an injection molding method.

14. A copolymer foam containing a polyamide block and a polyether block, which can be obtained by the manufacturing method described in any one of claims 1 to 13.

15. 0.8 g / cm ３ The following densities, preferably 0.05 to 0.8 g / cm³ ３ More preferably 0.08–0.5 g / cm³ ３ And, more preferably, 0.08 to 0.3 g / cm³ ３ The foam according to claim 14, having the density of [a certain value].

16. The foam according to claim 14 or 15, having an expansion rate in the range of 2 to 25, preferably 3 to 20, and more preferably 4 to 15.

Images