Process for preparing a crosslinked polyester of glycerol and a dicarboxylic acid using a cyclic carboxylic polyanhydride in the presence of a catalyst

Abstract

The present invention relates to a process for preparing a crosslinked glycerol polyester and a dicarboxylic acid monomer, comprising a step of crosslinking a glycerol polyester and a dicarboxylic acid monomer with a cyclic polycarboxylic anhydride A in the presence of a sulfonic acid compound, the cyclic polycarboxylic anhydride A comprising at least two cyclic carboxylic anhydride groups, the cyclic polycarboxylic anhydride A not comprising any linear carboxylic anhydride functions. The present invention also relates to a crosslinking composition useful for carrying out the process of the invention.

Description

Title of the invention: Process for preparing a crosslinked polyester of glycerol and a dicarboxylic acid using a cyclic polycarboxylic anhydride in the presence of a catalyst. FIELD OF THE INVENTION

[0001] The present invention relates to crosslinked polyesters of glycerol and a dicarboxylic acid monomer. The present invention also relates to a process for their preparation and a crosslinking composition useful for the preparation of said crosslinked polyesters. STATE OF THE ART

[0002] Biodegradable and / or bio-based polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), poly(glycerol sebacate) (PGS) and their copolymers, are now ubiquitous in the preparation of biomaterials useful both as medical biomaterials and for surface coatings for various fields of application.

[0003] Conventionally, these polyesters are prepared by melt polycondensation of glycerol and a diacid at high temperature, with fairly long reaction times. These reaction times are further extended to modify the mechanical properties of the polyester via crosslinking.

[0004] There is therefore a need for processes for preparing crosslinked polyesters with shorter crosslinking times and / or lower reaction temperatures - therefore compatible with a greater number of additives and in particular active ingredients to be encapsulated in said crosslinked polyesters - while maintaining or even improving mechanical properties suitable for the intended uses. Description of the invention

[0005] The inventors have demonstrated that the use of a crosslinking agent of the cyclic carboxylic polyanhydride type in the presence of a sulfonic acid compound made it possible to overcome the problems of the prior art.

[0006] Thus, the present invention relates to a process for preparing a crosslinked glycerol polyester and a dicarboxylic acid monomer, comprising a crosslinking step of a glycerol polyester and a dicarboxylic acid monomer with a cyclic carboxylic polyanhydride A in the presence of a sulfonic acid compound, the cyclic carboxylic polyanhydride A comprising at least two cyclic carboxylic anhydride groups, the cyclic carboxylic polyanhydride A not comprising a linear carboxylic anhydride group.

[0007] The process of the invention thus makes it possible to achieve shorter crosslinking times.

[0008] Advantageously, the dicarboxylic acid monomer has the formula [HOOC-(CH2) p-COOH], in which p is a number from 1 to 30, preferably a number from 1 to 10, advantageously sebacic acid (p=8).

[0009] Advantageously, the polyester of glycerol and a dicarboxylic acid monomer has a number-average molar mass Mn less than or equal to 10,000 g / mol.

[0010] Advantageously, the crosslinked polyester of glycerol and a dicarboxylic acid monomer is a poly(glycerol-sebacate) having a number molar mass Mn less than or equal to 10,000 g / mol.

[0011] Advantageously, the cyclic carboxylic anhydride groups of the cyclic carboxylic polyanhydride A are independently selected from ortho phthalic, succinic, maleic, homo phthalic and isatoic groups.

[0012] Advantageously, the cyclic carboxylic anhydride groups of the cyclic carboxylic polyanhydride A are joined, linked together by at least one covalent bond or linked by a spacer group L.

[0013] L representing -O- ; -S- ; -S(O)- ; -S(O)2- ; -C(O)- ; -NRnRn- with Rn and Rn independently chosen from H or a Ci-C6 alkyl group, or a multivalent hydrocarbon group comprising 1 to 40 carbon atoms, cyclic or acyclic, saturated, unsaturated or aromatic, and which may contain one or more heteroatoms of O, S, Cl, Br, F, N, P or Si,

[0014] L being devoid of linear anhydride groups.

[0015] Advantageously, the cyclic carboxylic polyanhydride A comprises or is a compound of formula (I) or (II): 0 p (I) or Y ' 1 X'O to Ji .J odx 'Z{ A 'Zf "'O • y PL OO (II) xAd-VA s « > » î

[0016] in which • Li represents a bond; -O-; -S-; -S(O)-; -S(O)2-; -NRnRn- with Rn and Rn independently chosen from H or a Ci-C6 alkyl group; -C(O)-; or an aliphatic chain of 1 to 30 carbon atoms, in which 1 to 6 methylene units are optionally replaced by an arylene group, a heteroarylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-, -NRm- with Rm selected from H or a C6-alkyl group, -P-, -P(O)-, -SiRaRb- with Ra and Rb independently representing an -OH, C6-alkyl or C6-alkoxy group,

[0017] said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two C6-alkyl, C6-alkoxy, hydroxyl, nitro, cyano, halogen, or C6-haloalkyl groups. • Zi is absent or represents a -CH2- (methylene) or -NH- group, • Z2 is absent or represents a -CH2- (methylene) or -NH- group, • X independently represents an alkyl group in the form of Ci-C6, a hydroxyl group, an alkoxy group in the form of CrC6, a nitro group, a cyano group, or a halogen atom, • n represents an integer from 0 to 3, preferably from 0 to 2, • Y independently represents an alkyl group in CrC 6, a hydroxyl, alkoxy (Ci-C6), nitro, cyano, or halogen atom, • m represents an integer from 0 to 3, preferably from 0 to 2, • Ai represents:

[0018] - A C-C bond or a C=C bond linking the four carbon atoms of the two carboxylic anhydride functions,

[0019] - a saturated, unsaturated or aromatic carbohydrate, optionally bridged, said carbocycle comprising 4 to 30 carbon atoms, or

[0020] - a saturated, unsaturated or aromatic heterocycle, optionally bridged,

[0021] said heterocycle comprising from 4 to 30 carbon atoms, and

[0022] said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents selected from a Ci-C6 alkyl group, a hydroxyl, a Ci-C6 alkoxy, nitro, cyano, or halogen atom.

[0023] Typically, the crosslinking step comprises the following steps: a. contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid, with 0.1 to 200 parts by weight of at least one cyclic polycarboxylic anhydride as defined above, to obtain a mixture of crosslinking precursors, in the presence of 0.0001% by mass (0.1 ppm) to 1% by mass (1000 ppm), relative to the mass of polyester of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound, b. pressurizing the mixture obtained in the crosslinking precursor step of step a) to a target temperature Tc between 60°C and 175°C, and for a heating time under pressure sufficient to obtain a cross-linked polyester, c. cooling and recovery of the crosslinked polyester.

[0024] Advantageously, step a) comprises contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid with 10 to 100 parts by weight of at least one cyclic carboxylic polyanhydride as defined.

[0025] Advantageously, step a) includes the use of 0.05 wt% (500ppm) to 1 wt% (1000ppm) relative to the polyester mass of glycerol and a dicarboxylic acid monomer of a sulfonic acid compound.

[0026] Another object of the invention relates to a crosslinking composition, comprising: • 100 parts by weight of at least one polyester, glycerol, and a monomer dicarboxylic acid, • from 0.1 to 200 parts by weight of at least one cyclic carboxylic polyanhydride, • from 0.0001% mass (0.1 ppm) to 1% mass (1000 ppm) relative to the mass of polyester of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound.

[0027] Advantageously, the dicarboxylic acid monomer has the formula [HOOC-(CH 2)P-COOH], in which p is a number from 1 to 30, preferably a number from 1 to 10, advantageously sebacic acid (p=8).

[0028] Advantageously, the polyester of glycerol and a dicarboxylic acid monomer has a number molar mass Mn less than or equal to 10,000 g / mol.

[0029] Advantageously, at least one cyclic carboxylic polyanhydride comprises a compound of formula (I) or (II): OO (H) To Al J: .......

[0030] in which • Li represents a bond; -O-; -S-; -S(O)-; -S(O)2-; -NRnRn- with Rn and Rn independently chosen from H or a Ci-C6 alkyl group; -C(O)-; or an aliphatic chain of 1 to 30 carbon atoms, in which 1 to 6 methylene unit(s) is / are optionally replaced by a group arylene, a heteroarylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-, -NRm- with Rm selected from H or a Ci-C6 alkyl group, ; -P-, -P(O)-, -SiRaRb- with Ra and Rb independently representing a -OH, Ci-C6 alkyl or Ci-C6 alkoxy group,

[0031] said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two Ci-C6 alkyl, Ci-C6 alkoxy, hydroxyl, nitro, cyano, halogen, or Ci-C6 haloalkyl groups, • Zi is absent or represents a -CH2- (methylene) or -NH- group, • Z2 is absent or represents a -CH2- (methylene) or -NH- group, • X independently represents an alkyl group in the form of Ci-C6, a hydroxyl group, an alkoxy group in the form of CrC6, a nitro group, a cyano group, or a halogen atom, • n represents an integer from 0 to 3, preferably from 0 to 2, • Y independently represents an alkyl group in CrC 6, a hydroxyl, alkoxy (Ci-C6), nitro, cyano, or halogen atom, • m represents an integer from 0 to 3, preferably from 0 to 2. • Ai represents:

[0032] - a C-C bond or a C=C bond linking the four carbon atoms of the two carboxylic anhydride functions,

[0033] - a saturated, unsaturated or aromatic carbohydrate, optionally bridged, said carbocycle comprising 4 to 30 carbon atoms, or

[0034] - a saturated, unsaturated or aromatic heterocycle, optionally bridged,

[0035] said heterocycle comprising from 4 to 30 carbon atoms, and

[0036] said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents selected from a Ci-C6 alkyl group, a hydroxyl, a Ci-C6 alkoxy, nitro, cyano, or halogen atom.

[0037] Advantageously, Li represents an aliphatic bond or chain of 1 to 6 carbon atoms, in which one or two methylene unit(s) is / are optionally replaced by an arylene, -C(O)-, -O-, -S-, -S(O)-, -S(O)2- group,

[0038] said aliphatic chain being substituted or unsubstituted by a group preferably selected from a CrC6 alkyl, Ci-C6 alkoxy, or Ci-C6 haloalkyl.

[0039] Advantageously, the sulfonic acid compound is chosen from para-toluenesulfonic acid, para-dodecylbenzenesulfonic acid, methyl sulfonic acid or ethyl sulfonic acid.

[0040] Advantageously, the sulfonic acid compound is para-toluene sulfonic acid. DETAILED DESCRIPTION OF THE INVENTION DEFINITIONS

[0041] For the purposes of the present invention, the term “a” or “an” means “one or more” or “at least one”.

[0042] For the purposes of the present invention, a range of values ​​designated by the expression "between a and b" represents the range of values ​​from greater than strictly a, to less than strictly b (that is to say excluding the bounds a and b), while any range of values ​​designated by the expression "from a to b" represents the range of values ​​from a to b, that is to say including the strict bounds a and b.

[0043] In this description, "approximately" means that the value in question may be 10% lower or higher, in particular 5%, and especially 1% higher, than the value indicated.

[0044] By "ppm", one commonly means "parts per million". In the context of the invention, ppm refers to the mass of polyester, glycerol, and a dicarboxylic acid monomer.

[0045] The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of already used materials, that is to say, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, monomers, specifically glycerol, dicarboxylic acid monomers, and cyclic polycarboxylic anhydride.

[0046] Glycerol is a triol with the following formula: HO^X^OH

[0047] In the present invention, a "cyclic polycarboxylic anhydride" means an organic compound comprising at least two cyclic carboxylic anhydride functional groups. Each functional group is selected from either a carboxylic anhydride or a nitrogen anhydride functional group. A "cyclic carboxylic anhydride (nitrogen or non-nitrogen) functional group" is bonded to two carbons of the rest of the molecule, whether adjacent or not, so as to form a ring comprising a carboxylic anhydride or a nitrogen anhydride functional group. In contrast, a "linear anhydride (nitrogen or non-nitrogen) functional group" means a divalent carboxylic anhydride functional group (nitrogen or non-nitrogen) that is bonded to two carbons of the rest of the molecule but is not part of a ring.

[0048] In the present invention, a "carboxylic anhydride function" corresponds to the formula -C(=O)-OC(=O)-. This function is divalent.

[0049] In the present invention, a "nitrogenous carboxylic anhydride function" corresponds to the formula -C(=O)-OC(=O)-NH. This function is divalent.

[0050] In the present invention, a "cyclic carboxylic anhydride group" means a group comprising a cyclic carboxylic anhydride function (nitrogenous or non-nitrogenous) and further comprising from 3 to 40 carbon atoms. The cyclic anhydride group may be multivalent or monovalent. When the cyclic anhydride group is an isatotic group, then the cyclic anhydride group comprises a nitrogenous anhydride function.

[0051] When the group is further substituted, it comprises from 1 to 4, preferably from 1 to 2, substituents. The substituent(s) is / are, independently, preferably a Ci-C6 alkyl group, a Ci-C6 alkoxy group, a hydroxyl, nitro, cyano, halogen atom, or a Ci-C6 haloalkyl group.

[0052] A "linear anhydride group" is understood in the context of the invention to be a group comprising a linear carboxylic anhydride function (nitrogenous or non-nitrogenous). Unlike a cyclic anhydride group, in a linear carboxylic anhydride group, the divalent carboxylic anhydride function (nitrogenous or non-nitrogenous) is bonded to two carbons of the rest of the molecule, but is not contained within a ring.

[0053] In the present invention, a "monovalent hydrocarbon group" means a monovalent hydrocarbon chain that is saturated (i.e., containing no unsaturation or multiple bonds), unsaturated (i.e., containing at least one double or triple bond, without being aromatic), or aromatic, cyclic or acyclic (linear or branched) and has from 1 to 40 carbon atoms. A monovalent hydrocarbon group includes, in particular, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, or cycloalkynyl groups, substituted or unsubstituted, in the form C1-C40. Preferably, a monovalent hydrocarbon group is an alkyl, cycloalkyl, alkenyl, or cycloalkenyl group, substituted or unsubstituted, in the form C1-C40.

[0054] As used herein, a "divalent hydrocarbon group" means a saturated, unsaturated, or aromatic, cyclic or acyclic (linear or branched) divalent hydrocarbon chain comprising from 1 to 40 carbon atoms. A divalent hydrocarbon group includes, in particular, substituted or unsubstituted, linear or branched, C1-C40 alkanediyl, alkenediyl, or alkynediyl groups. A divalent hydrocarbon group also includes substituted or unsubstituted, C1-C40 cycloalkanediyl, cycloalkenediyl, or cycloalkynediyl groups. A divalent hydrocarbon group also includes a substituted or unsubstituted divalent aromatic group. Preferably, a hydrocarbon group monovalent is an alkanediyl (linear or branched), alkenediyl (linear or branched), cycloalkanediyl, cycloalkenediyl, substituted or unsubstituted, Ci-C40 group.

[0055] In the present invention, a "multivalent hydrocarbon group" means a hydrocarbon chain with a valence of four or more, saturated, unsaturated (i.e. comprising at least one double or possibly one triple C-C bond, but non-aromatic) or aromatic, cyclic or acyclic (linear or branched), comprising from 1 to 40 carbon atoms.

[0056] By "aliphatic" is meant a linear, branched and / or cyclic hydrocarbon group, whether saturated or unsaturated but non-aromatic.

[0057] For the purposes of this invention, the term "alkyl group" means a monovalent, saturated, linear or branched hydrocarbon chain comprising from 1 to 40 carbon atoms, preferably comprising from 1 to 10 carbon atoms. Examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl groups.

[0058] For the purposes of this invention, the term "cycloalkyl group" refers to a monovalent cyclic saturated hydrocarbon chain comprising 3 to 40 cyclic carbon atoms. A cycloalkyl group may be monocyclic, bicyclic, or polycyclic. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl groups. Adamantyl is an example of a polycyclic cycloalkyl group.

[0059] For the purposes of this invention, the term "alkenyl group" refers to a monovalent, linear or branched hydrocarbon chain comprising at least one double bond and from 2 to 40 carbon atoms. Examples include ethenyl, propenyl, allyl, butenyl, pentenyl, and hexenyl groups.

[0060] For the purposes of this invention, the term "cycloalkenyl group" refers to a monovalent cyclic hydrocarbon chain comprising 3 to 40 cyclic carbon atoms and at least one cyclic double bond. A cycloalkenyl may be monocyclic, bicyclic, or polycyclic. Examples include cyclobutenyl, cyclopentenyl, cyclohexenyl, and cycloheptenyl. A polycyclic cycloalkenyl is bicyclo[2.2.2]oct-7-ene.

[0061] For the purposes of this invention, the term "aie y ny le" refers to a monovalent hydrocarbon chain, linear or branched, comprising at least one triple bond and consisting of 2 to 40 carbon atoms. Examples include ethynyl, propynyl, butynyl, pentynyl, and hexynyl groups.

[0062] For the purposes of this invention, a "cycloalkynyl" group is defined as a monovalent cyclic hydrocarbon chain comprising 5 to 40, preferably 7 to 40, cyclic carbon atoms and at least one triple bond cyclic. A cycloalkynyl group can be monocyclic, bicyclic, or polycyclic. The cycloheptynyl group is an example.

[0063] For the purposes of this invention, the term "aromatic group" means an aromatic hydrocarbon group, preferably comprising 6 to 40 carbon atoms, and including one or more fused rings. Examples of monovalent aromatic groups include phenyl, naphthyl, or pyrene, advantageously phenyl. Examples of divalent aromatic groups include phenylene, naphthylene, or pyrenylene, advantageously pyrenylene.

[0064] By "alkanediyl" group, for the purposes of the present invention, means a divalent acyclic hydrocarbon chain, linear or branched, comprising from 1 to 40 carbon atoms, such as, for example, a methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, or hexanediyl group.

[0065] By "cycloalkanediyl" group, in the context of the present invention, we mean a saturated divalent cyclic hydrocarbon group, comprising from 3 to 40 cyclic carbon atoms, such as, for example, a cyclobutylene, cyclohexylene or cyclopentylene group.

[0066] By "alkenediyl" group, for the purposes of the present invention, means a divalent acyclic hydrocarbon chain, linear or branched, comprising from 2 to 40 carbon atoms and at least one double bond, such as, for example, a vinylene (ethenylene) or propenylene group.

[0067] By "cycloalkenidiyl" group, for the purposes of the present invention, is understood to mean a cyclic, linear or branched, divalent hydrocarbon chain comprising from 3 to 40 atoms, preferably from 4 to 40 or even from 5 to 40 carbon atoms and at least one double bond, such as, for example, a cyclopentenylene group.

[0068] By "alkynediyl" group, for the purposes of the present invention, is understood to be a divalent, linear or branched, acyclic hydrocarbon chain comprising from 2 to 40 carbon atoms and at least one triple bond.

[0069] For the purposes of this invention, a "cycloalkyndiyl" group is defined as a monovalent cyclic hydrocarbon chain comprising 5 to 40, preferably 7 to 40 or even 8 to 40, cyclic carbon atoms and at least one cyclic triple bond. A cycloalkyndiyl group may be monocyclic, bicyclic, or polycyclic.

[0070] For the purposes of this invention, the term "C1-C6 alkoxy group" refers to a C1-C6 alkyl group, as defined above, linked to the rest of the molecule via an oxygen atom. Examples include methoxy, ethoxy, n-propoxy, ao-propoxy, n-butoxy, sec-butoxy, t-butoxy, n-pentoxy, and n-hexoxy.

[0071] By "halogen atom" or "halogen", for the purposes of the present invention, means the atoms of fluorine, chlorine, bromine and iodine, preferably the atoms of fluorine and chlorine.

[0072] For the purposes of this invention, the term “Ci-C6 haloalkyl group” means a Ci-C6 alkyl group, as defined above, in which one or more hydrogen atoms are replaced by a halogen atom, in particular a chlorine, bromine, iodine, or fluorine atom, preferably a fluorine atom. The trifluoromethyl (-CF3) group is an example.

[0073] The hydroxy group is the -OH group. The cyano group is the -CN group. The nitro group is the -NO2 group.

[0074] A "carbocycle comprising from 4 to 30 carbon atoms" means a cyclic (monovalent) hydrocarbon group comprising from 4 to 30 carbon atoms. A carbocycle may be monocyclic or polycyclic, optionally bridged (including bridged and / or fused rings). When the carbocycle is polycyclic, it comprises at least 2, advantageously 2 or 3, fused or bridged rings. The carbocycle may be saturated (i.e., containing no unsaturation or multiple bonds), unsaturated (i.e., containing at least one double bond or possibly one triple bond, without being aromatic), or aromatic. When the carbocycle is aromatic, it is referred to as an "aryl" group.

[0075] For the purposes of this invention, "heterocycle comprising 4 to 30 carbon atoms" means a (monovalent) ring of 4 to 30 carbon atoms, saturated, unsaturated, or aromatic, monocyclic or polycyclic, optionally bridged (including bridged and / or bonded rings), of which one or more, advantageously 1 to 4, more advantageously 1 or 2, atom(s) of the ring is / are a heteroatom, such as, for example, sulfur, nitrogen, or oxygen atoms, the other cyclic atoms being carbon atoms. Examples of saturated or unsaturated heterocycles are: pyrrolidine, piperidine, piperazine, morpholine, pyrazolidinyl, imidazolidine, azepane, thiazolidine, isothiazolidine, oxazocane, thiazepane, and benzimidazolone.

[0076] An “aromatic heterocycle”, also called a heteroaryl (monovalent) group, comprises 5 to 10 ring atoms, one or more of which are heteroatoms, advantageously 1 to 4 and even more advantageously 1 or 2, such as, for example, sulfur, nitrogen, or oxygen atoms, the other ring atoms being carbon atoms. Examples of heteroaryl groups are furan, thiophene, pyrrole, pyridine, imidazole, triazolyl, tetrazole, oxazole, isoxazole, thiazole, isothiazole, pyrazole, oxadiazole, thiadiazole, pyridazine, pyrimidine, pyrazine, triazine, quinole, isoquinole, quinoxal, or indole.

[0077] An "arylene group" is understood to mean a divalent aromatic hydrocarbon group, preferably comprising 6 to 10 carbon atoms, and comprising one or more fused rings, such as, for example, a phenyl or naphthyl group. Advantageously, this refers to phenylene.

[0078] A "heteroarylene group" is understood to mean a divalent aromatic heterocycle, comprising from 5 to 10 ring atoms, one or more of which are heteroatoms, advantageously 1 to 4 and even more advantageously 1 or 2, such as, for example, sulfur, nitrogen or oxygen atoms, the other ring atoms being carbon atoms. Pyridinylene may be cited as an example.

[0079] According to the invention, an "orthophthalic group" is understood to be a group of formula: O, preferably of formula: p, this group bb being linked to the rest of the polyanhydride molecule by the -X bond, or of a divalent group of formula: p, this group being linked to the rest of the molecule J p '"AJ b of polyanhydride by the p- bond on one side, and by the -p bond on the other. The orthophthalic group can be substituted or unsubstituted.

[0080] In the present invention, a "succinic group" means a monovalent group of formula: p, this group being linked to the rest of the molecule ! T bb of polyanhydride via the A bond, and which may be substituted or unsubstituted, or of a divalent group of formula: p, this grouping being linked to the rest of the b polyanhydride molecule via the .L bond on one side, and via the • y bond on the other part. A succinic group is distinct from an orthophthalic group, so that in general, a divalent succinic group is not attached to a phenyl group.

[0081] In the present invention, a "maleic group" means a monovalent group of formula: p, this group being linked to the rest of the molecule O of polyanhydride by bonding and which may be substituted or unsubstituted, or of a divalent group of formula: p - ÿ, this grouping then being connected to the rest of D3 b the polyanhydride molecule by the bond on one side, and by the -p bond on the other part. A maleic group is distinct from an orthophthalic group, so that in general, a cyclic anhydride group of divalent maleic nature is not attached to a phenyl group.

[0082] In the present invention, a "homo-phthalic group" means a group of formula: O, preferably of formula: O, this WULJ 1 -O" XO 'SQ group being linked to the rest of the polyanhydride molecule by the p bond, or a divalent group with the formula: O, this grouping being linked to the rest of the polyanhydride molecule by the .-1- bond on the one hand, and by the bond ■ -on the other hand. The homophthalic group can be substituted or unsubstituted.

[0083] In the present invention, an "isatotic grouping" means a group formula: Preferably, the following formula: O or N' "OH N" 'OH O this group being linked to the rest of the polyanhydride molecule by the bond, or of a divalent group of formula: O, this rU H the group being linked to the rest of the polyanhydride molecule by the A bond on one side, and by the ■' bond on the other. The isato group can be substituted or unsubstituted.

[0084] By "room temperature" is meant here a temperature generally between 15°C and 40°C, preferably between 20°C and 30°C, in particular about 25°C. Process for preparing a crosslinked polyester

[0085] The invention relates to a process for preparing a crosslinked polyester of glycerol and a dicarboxylic acid, comprising a step of crosslinking a polyester of glycerol and a dicarboxylic acid with a cyclic polycarboxylic anhydride A in the presence of a sulfonic acid compound, the cyclic polycarboxylic anhydride A comprising at least two cyclic carboxylic anhydride groups, the cyclic polycarboxylic anhydride A not comprising linear carboxylic anhydride functions.

[0086] Polyester of glycerol and a starting dicarboxylic acid monomer (i.e., before crosslinking)

[0087] The dicarboxylic acid monomer can be aliphatic, aromatic, or aliphatic / aromatic. An aliphatic / aromatic dicarboxylic acid monomer comprises an aliphatic portion and an aromatic portion. The dicarboxylic acid monomer preferably comprises from 4 to 36 carbon atoms.

[0088] According to preferred embodiments of the invention, the dicarboxylic acid monomer is aliphatic, in particular saturated, especially linear or branched, preferably a (C3-C2o)alkanediyldiacid carboxylic acid, more preferably a (C8-Ci5)alkanediyldiacid carboxylic acid. A (Cx-Cy)alkanediyl group is a divalent, saturated, linear or branched hydrocarbon group comprising x to y carbon atoms.

[0089] Advantageously, the dicarboxylic acid monomer comprises or consists of a diacid of general formula [HOOC-(CH2)P-COOH] in which p is a number from 1 to 30, preferably a number from 5 to 10.

[0090] In particular, the dicarboxylic acid monomer can be selected from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, hexadecanedioic acid, octadecanedioic acid and a mixture of two or more of these dicarboxylic acids.

[0091] Preferably, the dicarboxylic acid monomer can be chosen from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and a mixture of two or more of these dicarboxylic acids.

[0092] According to variants of the invention, the dicarboxylic acid monomer can be a mixture of at least two dicarboxylic acids. Preferably, the dicarboxylic acid monomer comprises sebacic acid.

[0093] Preferably, the dicarboxylic acid monomer comprises or consists of sebacic acid.

[0094] According to preferred embodiments of the invention, the dicarboxylic acid monomer and glycerol are the only monomers during polycondensation. Most preferably, the sebacic acid monomer and glycerol are the only monomers constituting the glycerol polyester and a dicarboxylic acid monomer.

[0095] Advantageously, the molar ratio of glycerol / dicarboxylic acid monomer varies from 1 to 10 / 1, in particular from 1 / 1 to 5 / 1, preferably from 1 / 1 to 2 / 1.

[0096] Glycerol polyester and a dicarboxylic acid monomer (hereinafter referred to as non-crosslinked polyester) advantageously has one or more of the following characteristics:

[0097] - an average number-average molar mass (Mn) of the non-crosslinked polyester greater than or equal to 800 g / mol, preferably greater than or equal to 900 g / mol;

[0098] - an average number-average molar mass (Mn) of the non-crosslinked polyester lower or equal to 10,000 g / mol, preferably less than or equal to 7,000 g / mol, preferably less than or equal to 5,000 g / mol;

[0099] - a polydispersity index Ip (Mw / Mn) of the uncrosslinked polyester of less than 10, preferably less than or equal to 8;

[0100] - a residual monomer content less than or equal to 5% by weight of the weight of non-crosslinked polyester;

[0101] - a level of (1,2,3-triacylglyceride) units less than or equal to 20 mol%, in particular less than or equal to 15 mol%, relative to all units of the non-crosslinked polyester;

[0102] - a molar ratio of the unit (1,3-diacylglyceride) to the unit (1,2-diacylglyceride) greater than 1 of non-crosslinked polyester.

[0103] The polyester of glycerol and a dicarboxylic acid monomer can be obtained in particular by implementing the processes described in EP3149067 and EP1448656.

[0104] The number-average molar mass (Mn), the mass-average molar mass (Mw), and the polydispersity index (also called polydispersity and denoted D, which is the ratio Mw / Mn), can be measured in a known manner by size-exclusion chromatography (SEC) analysis, in particular as described below.

[0105] The residual monomer content and the (1,2,3-triacylglyceride) unit content is measured in a known manner by 'H NMR, where appropriate combined with 2D HSQC / HMBC and 13C NMR experiments. cyclic carboxylic polyanhydride

[0106] Preferably, the cyclic carboxylic polyanhydride comprises two cyclic carboxylic anhydride functions, that is to say, it is a cyclic bis-carboxylic anhydride.

[0107] In the present invention, the cyclic carboxylic anhydride groups of the cyclic carboxylic polyanhydride A are preferably independently selected from orthophthalic, succinic, maleic, homophthalic and isatoic groups.

[0108] The cyclic carboxylic polyanhydride may comprise identical or different cyclic carboxylic anhydride groups. Preferably, the cyclic carboxylic anhydride groups of the cyclic carboxylic polyanhydride are identical.

[0109] Advantageously, the cyclic carboxylic anhydride groups are independent of the orthophthalic, succinic or maleic groups.

[0110] Advantageously, the cyclic carboxylic anhydride groups of the cyclic polycarboxylic anhydride A are joined or linked to each other by at least one covalent bond or linked by a spacer group L,

[0111] L representing -O- ; -S- ; -S(O)- ; -S(O)2- ; -NRn- with Rn selected from H or a Ci-C6 alkyl group; -C(O)- ; or a multivalent hydrocarbon group comprising 1 to 40 carbon atoms, cyclic or acyclic, saturated, unsaturated or aromatic, and which may contain one or more heteroatoms of O, S, Cl, Br, F, N, P or Si, and

[0112] L being devoid of linear anhydride groups.

[0113] Chemically stable ballast. Thus, an oxygen atom cannot be bonded to another oxygen atom and a nitrogen atom cannot be bonded to another nitrogen atom. Therefore, L is preferably devoid of peroxide (-OO-) or hydrazine (-NH-NH- or -NH-N(Ci-C6 alkyl)- or -N(Ci-C6 alkyl)-N(Cr-C6 alkyl) groups. Similarly, an ester (C(O)O) function cannot be bonded to another ester function. Furthermore, L is advantageously devoid of readily hydrolyzable groups. In particular, L is devoid of linear anhydride groups, especially linear (divalent) carboxylic anhydride groups of the formula -OC(=O)-O-. Advantageously, L is also devoid of ester (-OC(=O)-) or amide (-OC(=O)-NR-) functions, with R representing H or a substituent such as a hydrocarbon chain.

[0114] The valence of the L group is even (since L carries cyclic carboxylic anhydride groups, which are divalent), and generally of 4 or 6, preferably of 4.

[0115] Advantageously, L represents a multivalent hydrocarbon group comprising 1 to 40 carbon atoms, cyclic or acyclic, saturated, unsaturated or aromatic, and able to contain one or more heteroatoms of O, S, Cl, Br, F, N, P or Si, which means that L then represents a cyclic or acyclic, saturated, unsaturated or aromatic multivalent hydrocarbon group, comprising 1 to 40 carbon atoms, in which one or more carbon atoms can be replaced by one or more heteroatoms of O, S, Cl, Br, F, N, P or Si or by a -C(O)- group.

[0116] Phosphorus (P), sulfur (S), nitrogen (N) and silicon (Si) atoms can be in oxidized form (in particular P(O), SO, SO2), and / or substituted - in particular by an alkyl group in Ci-C6 - depending on the valence of the atom.

[0117] Particularly advantageously, L represents a cyclic or acyclic, saturated, unsaturated or aromatic multivalent hydrocarbon group, comprising 1 to 40 carbon atoms, in which one or more carbon atoms can be replaced by one or more oxygen (O) atoms or a -C(O)- or -S(O)2- group, and optionally by one or more heteroatoms of Cl, Br, F, N, P or Si.

[0118] According to particular embodiments, L represents a multivalent acyclic hydrocarbon group, saturated or unsaturated, comprising 1 to 10 carbon atoms, in which one or more carbon atoms can be replaced by one or more oxygen (O) atoms or a -C(O)-, -S-, -S(O)-, -S(O)2- group, and optionally by one or more heteroatoms of Cl, Br, F, N, P or Si.

[0119] According to other particular embodiments, L represents a saturated, unsaturated, or aromatic cyclic multivalent hydrocarbon group comprising 3 to 40 carbon atoms, wherein one or more carbon atoms may be replaced by one or more oxygen (O) atoms or a -C(O)- group, and optionally by one or more heteroatoms of S, Cl, Br, F, N, P, or Si, preferably a heteroatom of Cl, Br, or F. In these embodiments, the multivalent group may be monocyclic, bicyclic, or polycyclic. When L is bicyclic or polycyclic, it advantageously comprises one or more fused rings.

[0120] In particular embodiments, the cyclic carboxylic polyanhydride comprises or is made up of a compound of formula (I) or preferably of formula (la): OO (the) o "ï o ÿ......''Y 0 (X)„ ' 0

[0121] in which • Li represents a bond; -O-; -S-; -S(O)-; -S(O)2-; -NRnRn- with Rn and Rn- independently chosen from H or a Ci-C6 alkyl group; -C(O)-; or an aliphatic chain of 1 to 30 carbon atoms, in which 1 to 6 methylene unit(s) (preferably non-adjacent) is / are optionally replaced by an arylene group; a heteroarylene group; -C(O)-; -O-; -S-; -S(O)-; -S(O)2-; -NRm- with Rm chosen from H or a CrC6 alkyl group; -P-; -P(O)-; -SiRaRb- with Ra and Rb independently representing a -OH, C6-alkyl or C6-alkoxy group,

[0122] said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two, C6-alkyl, C6-alkoxy, hydroxyl, nitro, cyano, halogen, C6-haloalkyl, group, • Zi is absent or represents a -CH2- (methylene) or -NH- group, • Z2 is absent or represents a -CH2- (methylene) or -NH- group, • X independently represents an alkyl group in the form of Ci-C6, a hydroxyl group, an alkoxy group in the form of CrC6, a nitro group, a cyano group, or a halogen atom, • n represents an integer from 0 to 3, preferably from 0 to 2, • Y independently represents an alkyl group in Ci-C 6, a hydroxyl, alkoxy (Ci-C6), nitro, cyano, or halogen atom, • m represents an integer from 0 to 3, preferably from 0 to 2.

[0123] Preferably, Zi and Z2 are identical. Advantageously, Zi and Z2 both represent a link.

[0124] Preferably, Li represents a bond; -O-; -S-; -S(O)-; -S(O)2-; -C(O)-; or an aliphatic chain of 1 to 30 carbon atoms, wherein 1 to 6 methylene unit(s) (preferably non-adjacent) is / are optionally replaced by an arylene group, a heteroarylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-, -NRm- with Rm selected from H or a Ci-C6 alkyl group, said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two, groups alkyl in Ci-C6, alkoxy in Ci-C6, a hydroxyl, nitro, cyano, a halogen atony, a haloalkyl group in Ci-C6.

[0125] Preferably, Li represents a bond ; -O- ; -S(O)2- ; -C(O)- ; or an aliphatic chain of 1 to 20 carbon atoms, in which 1 to 4 (preferably 1 to 2) methylene unit(s) (preferably non-adjacent) is / are optionally replaced by an arylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-,

[0126] said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two, substituents preferably selected from a Ci-C6 alkyl, Ci-C6 alkoxy, or Ci-C6 haloalkyl. In particular, Li may comprise one or two divalent aromatic groups, such as phenylenes.

[0127] In particular, Li represents a GrG2-G3 radical where Gi and G3 are independently selected from O, -S(O)2, -C(O)- ; G2 is a divalent hydrocarbon group of 4 to 15 carbon atoms which may comprise one or two divalent aromatic groups, such as phenylenes, and which may be substituted by one or more, in particular one or two, preferably selected groups from a Ci-C6 alkyl, Ci-C6 alkoxy, or Ci-C6 haloalkyl.

[0128] Advantageously, Li represents a bond ; -O- ; -S(O)2- ; -C(O) ; or an aliphatic chain of 1 to 10 carbon atoms, in particular of 1 to 6 carbon atoms, in which 1 to 2 methylene unit(s) (preferably non-adjacent) is / are optionally replaced by an arylene, -C(O)-, -O-, -S-, -S(O)-, -S(O)2- group,

[0129] said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two group(s) preferably selected from a Ci-C6 alkyl, Ci-C6 alkoxy, or Ci-C6 haloalkyl.

[0130] Advantageously, Li represents a bond ; -O- ; -S(O)2- ; -C(O) ; or an aliphatic chain of 1 to 10 carbon atoms, in particular of 1 to 6 carbon atoms, wherein 1 to 2 methylene unit(s) (preferably non-adjacent) is / are optionally replaced by an arylene, -C(O)-, -O- group, said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two Ci-C6 alkyl, Ci-C6 alkoxy, hydroxyl, nitro, cyano, halogen atom, Ci-C6 haloalkyl group, typically substituted or unsubstituted by a Ci-C6 alkyl, Ci-C6 alkoxy, halogen atom, or Ci-C6 haloalkyl group.

[0131] In particular, X can independently represent a Ci-C6 alkyl group, a hydroxyl group, or a halogen atom.

[0132] Advantageously, n represents 0 or 1.

[0133] Preferably, Y can independently represent a Ci-C6 alkyl group, a hydroxyl group, or a halogen atom,

[0134] Advantageously, m represents 0 or 1.

[0135] According to particular variants, n and m independently represent 0 or 1, and X and Y independently represent a Ci-C6 alkyl group, a hydroxyl, or a halogen atom.

[0136] In other particular embodiments, the cyclic carboxylic polyanhydride comprises or is made up of a compound of formula (II) or preferably of formula (lia): OO (II) or s To Al > : ....... OO (lia) [ Ai ) p O 'O

[0137] in which

[0138] Zi is absent or represents a -CH2- (methylene) or -NH- group,

[0139] Z2 is absent or represents a -CH2- (methylene) or -NH- group,

[0140] Ai represents: • a C-C bond or a C=C bond linking the four carbon atoms of the two carboxylic anhydride functions, • a saturated, unsaturated or aromatic carbohydrate, said carbohydrate comprising from 4 to 30 carbon atoms, or • a saturated, unsaturated or aromatic heterocycle, said heterocycle comprising from 4 to 30 carbon atoms, and

[0141] said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents, in particular a Ci-C6 alkyl group, a Ci-C6 haloalkyl group, a hydroxyl, a Ci-C6 alkoxy, nitro, cyano, or a halogen atom.

[0142] According to some embodiments, Aire represents a polycyclic carbocycle or heterocycle of 10 to 30 members. In these embodiments, the polycyclic group may include fused rings. Advantageously, Aire represents a polycyclic aromatic carbocycle or heterocycle of 10 to 30 members, comprising two or more fused rings. This may, in particular, be a naphthalene group.

[0143] According to variants, Ai represents an aromatic carbocycle comprising 6 to 10 carbon atoms, such as a phenyl or a naphthalene.

[0144] According to other variants, Ai represents a saturated carbocycle (monocyclic or bicyclic) comprising from 4 to 10, preferably from 4 to 6, carbon atoms. Preferably, it is a saturated monocyclic carbocyclic comprising 4 to 6 carbon atoms.

[0145] According to variants, at least one of at least one cyclic carboxylic polyanhydride comprises or is made up of a compound of formula (III): O o (HD O' o oo

[0146] in which represents a simple or double DC connection

[0147] L2 and L3 taken together with the carbon atoms to which they are bonded represent a saturated, unsaturated or aromatic carbocycle or heterocycle, optionally bridged, said carbocycle or heterocycle comprising from 4 to 30 carbon atoms, and

[0148] said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents selected from a Ci-C6 alkyl group, a hydroxyl, a Ci-C6 alkoxy, nitro, cyano, or halogen atom.

[0149] Preferably, L2 and L3 taken together with the carbon atoms to which they are bonded represent a saturated, unsaturated or aromatic carbocycle, optionally bridged,

[0150] said carbocycle comprising from 4 to 10 carbon atoms, and

[0151] said carbocycle being substituted or not substituted by one or more (in particular 1 or 2) substituents chosen from a Ci-C6 alkyl group or a halogen atom.

[0152] Advantageously, L2 and L3 taken together with the carbon atoms to which they are bonded represent: • a saturated or unsaturated carbocycle, optionally bridged, comprising 4 to 8 carbon atoms, substituted or unsubstituted by one or more (in particular 1 or 2) substituents selected from a Ci-C6 alkyl group, halogen atom, or • an aromatic carbocycle of 6 to 10 carbon atoms, substituted or unsubstituted by one or more (in particular 1 or 2) substituents chosen from an alkyl group in Ci-C6, halogen atom.

[0153] In particular, L2 and L3 taken together with the carbon atoms to which they are bonded can represent a cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[2.2.2]oct-2-enyl, or a phenyl.

[0154] According to variants, the cyclic carboxylic polyanhydride comprises or is made up of a compound of formula (IV): OO (IV) \S y /

[0155] in which H represents a single or double DC connection.

[0156] According to preferred embodiments, the cyclic carboxylic polyanhydride is chosen from the group consisting of:

[0157] [Tables 1] Benzophenone-3,3',4,4'-tetracarboxylic acid bis-anhydride (BTDA) \ Vf" ----- 4,4'-(4,4'-Isopropylidenediphenoxy) phthalic acid bis-anhydride (BPADA) q A ' APF ï 'T ï 1 r F $ ü 4,4'-Diphthalic acid bis-anhydride (BPDA) 0 ■k Û "f 4,4'-Oxydiphthalic acid bis-anhydride (ODPA) 0 « d [ O 0 ...... k IL. / ° x '-' A 0 4,4'-Hexafluoroisopropyldenediphthalic acid bisanhydride (6FDA) \ i J " 4,4'-Isopropyldenediphthalic acid bisanhydride o ÿ / Y a 3,3',4,4'-Diphenylsulfonetetracarboxylic acid bisanhydride (DSDA) 0 A Ô y 6 OO o J j (j TP b 1,4,5,8-Naphthalenetetracarboxylic acid bisanhydride O P'x o

[0158] and a mixture of these.

[0159] Preferably, the cyclic carboxylic polyanhydride is BDTA, DPADA, BPDA and ODPA, or a mixture of these.

[0160] Cyclic polycarboxylic anhydrides, particularly the cyclic bis-carboxylic anhydrides of the invention, are well known to those skilled in the art (see, in particular, US 7,425,650). They can be obtained by condensation of the corresponding tetracarboxylic acids, and some are commercially available. More specifically, for the synthesis of cyclic polycarboxylic anhydrides comprising groups:

[0161] Homophthalic: the syntheses described in US 6,797,838 may be used or adapted;

[0162] Isotaoic: the syntheses described in "Sonochimie ultrasonique", Volume 14, Number 5, July 2007, pages 497-501, may be used or adapted. The sulfonic acid compound

[0163] The sulfonic acid compound is selected from compounds with the generic formula: R-SO3H

[0164] where: - R is an aliphatic or aromatic group comprising 1 to 18 carbon atoms. • When R is an aliphatic group, it can be an alkyl or cycloalkyl group, linear or branched. Specifically, when R is an aliphatic group, it can be chosen from among the following: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, octyl, nonyl, decyl, dodecyl, lauryl, stearyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclohexenyl, and cycloheptenyl. When R is an aliphatic group, the preferred choice is methyl (methylsulfonic acid) or ethyl (ethylsulfonic acid). • When R is an aromatic group, it can be a phenyl, substituted phenyl-alkyl, naphthyl, or substituted naphthyl-alkyl group. Specifically, when R is an aromatic group, it can be chosen from among the phenyl, ortho-methylphenyl, meta-methylphenyl, para-methylphenyl, para-octylphenyl, para-dodecylphenyl, xylyl, benzyl, 1-naphthyl, or 2-naphthyl groups. When R is an aromatic group, the preferred choice is para-methylphenyl (para-toluenesulfonic acid) or para-dodecylphenyl (para-dodecylbenzenesulfonic acid).

[0165] According to particular embodiments of the invention, the sulfonic acid compound is chosen from para-toluene sulfonic acid, para-dodecyl benzene sulfonic acid, methyl sulfonic acid or ethyl sulfonic acid.

[0166] Preferably, the sulfonic acid compound is para-toluene sulfonic acid or methyl sulfonic acid. Crosslinking

[0167] Advantageously, the crosslinking step comprises the following steps: a. contacting 100 parts by weight of at least one glycerol polyester and a dicarboxylic acid monomer, with 0.1 to 200 parts by weight of at least one cyclic carboxylic polyanhydride as defined herein, to obtain a crosslinking precursor mixture, in the presence of 0.000l mass% (0.1 ppm) to 1000ppm of a sulfonic acid compound relative to the mass of glycerol polyester and a dicarboxylic acid monomer, b. Pressurizing the mixture obtained in the crosslinking precursor step of step a) to a target temperature Tc between 60°C and 175°C, and maintaining it (at temperature Tc under pressure) for a heating time under pressure tch sufficient to obtain a crosslinked polyester, c. cooling and recovery of the crosslinked polyester.

[0168] At least one polyester of glycerol and a dicarboxylic acid and at least one cyclic polycarboxylic anhydride and the sulfonic acid compound are as defined above.

[0169] Typically, step a) includes contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid, with 10 to 100, in particular 15 to 90, parts by weight of at least one cyclic polycarboxylic anhydride.

[0170] Typically, the amount of sulfonic acid compound used in step a) varies in a range from 0.05 wt% (500 ppm) to 1 wt% (1000 ppm), preferably from 0.1 wt% (1000 ppm) to 0.9 wt% (9000 ppm), relative to the mass of polyester of glycerol and a dicarboxylic acid monomer.

[0171] Typically, step a) comprises contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid, with 10 to 100, in particular 15 to 90, parts by weight of at least one cyclic polycarboxylic anhydride in the presence of 0.1% by mass (1000ppm) to 0.9% by mass (9000ppm) of a sulfonic acid compound relative to the mass of polyester of glycerol and a dicarboxylic acid monomer.

[0172] Preferably, step a) of contacting is carried out in the absence of solvent or diluent. Preferably, step a) of contacting is carried out in the absence of any other additive.

[0173] Step a) comprises a mixture of at least one glycerol polyester and a dicarboxylic acid and at least one cyclic polycarboxylic anhydride, preferably at a temperature Ta allowing the melting of the glycerol polyester and a dicarboxylic acid monomer, and preferably a homogeneous dispersion of the cyclic polycarboxylic anhydride. Thus, Ta is typically between 20°C and 100°C, in particular between 30°C and 80°C.

[0174] Step a) includes the use of a sulfonic acid compound as a catalyst. This can be introduced into the mixture directly in solid form.

[0175] To promote homogenization, agitation can be implemented in a known manner. Thus, step a) is typically carried out under agitation.

[0176] According to particular variants of the invention, the contacting is carried out by the introduction of the cyclic carboxylic polyanhydride in solid form and the sulfonic acid compound in solid form.

[0177] Advantageously, in step b), a platen press will be used, the plates of which have been preheated to temperature Tc.

[0178] At step b), the temperature Tc is typically between 60°C and 175°C, preferably between 80°C and 160°C.

[0179] Advantageously, the overpressure applied by the press (relative to atmospheric pressure) in the heating step b) varies from 50 to 500 kPa (equivalent to 0.5 to 5 bar), in particular from 1 to 4 bar.

[0180] The heating time is determined by the duration between the moment the press is closed and the moment it is opened.

[0181] Generally, the heating time tch is between 10 and 2000 min.

[0182] During step c), the crosslinked polyester is typically cooled and recovered at room temperature and atmospheric pressure. II. Crosslinking Composition

[0183] The present invention also relates to a crosslinking composition, comprising: • 100 parts by weight of at least one polyester, glycerol, and a diacid carboxylic, • from 0.1 to 200 parts by weight of at least one cyclic carboxylic polyanhydride as defined above, • from 0.0001% mass (0.1 ppm) to 1% mass (1000 ppm) relative to the mass of polyester of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound.

[0184] Preferably, the composition comprises from 10 to 100, in particular from 15 to 90, parts by weight of at least one cyclic carboxylic polyanhydride.

[0185] Preferably the composition comprises from 0.05% by mass (500 ppm) to 1% by mass (10000 ppm), more preferably from 0.1% by mass (1000 ppm) to 0.9% by mass (9000 ppm), of sulfonic acid compound relative to the mass of glycerol polyester.

[0186] The polyester of glycerol and a dicarboxylic acid, as well as cyclic polycarboxylic anhydride and the sulfonic acid compound, may be as defined above in section 1. EXAMPLES

[0187] The following examples are given for illustrative purposes only, but should in no way be considered as limiting the present invention. 1. Materials and methods

[0188] 1.1. Characteristics of the starting products

[0189] Glycerol and sebacic acid polyester

[0190] [Tables2] Polyester Mn (g.mol Mw (g.mol 1) IP Poly glycerol se bacate 2656 16520 6.2

[0191] Procedure for the synthesis of the starting glycerol and sebacic acid polyester:

[0192] In a 10 L double-walled stainless steel reactor fitted with an instrumented distillation column configured for total reflux and a condenser connected to a distillate recovery vessel, glycerol (1.94 kg, 1 mol equiv.) is mixed with water (0.56 kg) at 40 °C under a nitrogen flow (0.5 L / min). Gentle stirring is applied (20 rpm) for 5 min. After the glycerol has dissolved, sebacic acid (4.25 kg, 1 mol equiv.) is added to the aqueous mixture in the reactor. Finally, the remaining water (0.56 kg) is added to the medium. The reactor vessel is then gradually heated, following a progressive temperature ramp with intermediate plateaus, until a shell temperature of 172°C is reached after 5 hours, corresponding to a surrounding medium temperature of 170°C, measured using a immersion probe. Agitation is increased to 80 rpm when the surrounding medium temperature exceeds 90°C.The medium is left under reflux at the beginning of the test. When the temperature of the vapors at the top of the distillation column reaches... 98°C, and after an equilibration time of 15 min, the column configuration is switched to total withdrawal in order to selectively recover the water produced during the reaction.

[0193] The esterification of the medium is carried out over a total period of 8 hours and 30 minutes, taking as the starting point the moment the distillation begins, approximately 30 minutes after the introduction of the reagents. The water distilled during the test is collected in a dedicated insulated recovery container.

[0194] Next, a vacuum system is connected to the distillation condenser and a pressure lower than atmospheric pressure is applied to the reactor contents. The pressure is reduced slowly and in steps (approximately 10 to 15% per step) over approximately 30 minutes until a target value of less than 30 mbar is reached.

[0195] Once the pressure in the reaction vessel stabilizes at 28 mbar, the medium is left to react at 170 °C for a further 4 hours. During this polycondensation step, the stirring speed is maintained at 80 rpm.

[0196] The PGS produced is transferred from the reactor vessel to a container and allowed to cool to room temperature. The product is then transferred to a freezer for storage, where it is frozen for at least approximately 24 hours before analysis.

[0197] Cyclic carboxylic polyanhydride

[0198] [Tables3] Bis-Anhydride Abbreviation M (g.mol 1) Benzophenone-3,3',4,4'-tetracarboxylic acid bis-anhydride BTDA 322.23 4,4'-(4,4'-Isopropylidenediphenoxy) bis(phthalic anhydride) BPADA 520.49

[0199] 1.2. Measurement methods Measurement of crosslinking kinetics:

[0200] The crosslinking kinetics were conducted using an ANTON PAAR MCR. The measurements consisted of monitoring the evolution of the elastic modulus of the compositions at 140°C with 1% strain and a frequency of 1 Hz. The crosslinking times of the different compositions were measured until the elastic modulus reached the value of IMPa. Macrostructure Analysis#: SEC RI

[0201] The SEC (Size Exclusion Chromatography) technique allows the separation of macromolecules in solution according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the largest being eluted first.

[0202] While not an absolute method, SEC allows for the determination of the molar mass distribution of a polymer. From commercial standard products, the various number-average (Mn) and weight-average (Mw) molar masses can be determined, and the polydispersity index (Ip = Mw / Mn), also called "dispersity," can be calculated.

[0203] The macrostructure of non-crosslinked polyesters is analyzed by size-exclusion chromatography with differential refractometer detection (SEC RI), using low-weight polystyrene (PS) calibration with medium-weight standards. Samples are dissolved at a concentration of approximately 1 g / L in butylated hydroxytoluene (BHT)-free THF, then stirred for two hours before injection. The analysis temperature is 35°C, with a mobile phase flow rate of 1 µL / minute on Agilent 2 Mixed E + 2 Mixed 2 columns. 2. Results

[0204] 2.1. Tested Formulations

[0205] The compositions studied are presented below. The contents are expressed as mass % and in ppm (parts per million) relative to the mass of polyester of glycerol and of a dicarboxylic acid monomer for the sulfonic acid compound.

[0206] The reference mixture T for each comparison is a mixture comprising a high molecular weight poly(glycerol sebacate) polymer and a cyclic carboxylic polyanhydride (i.e., cross-linked in the absence of a sulfonic acid compound). The preparation protocol used is the same as that described in section 2.2, but in the absence of a sulfonic acid compound. • Para-toluene sulfonic acid#

[0207] [Tables4] Tl Al A2 PGS % 83 83 83 BTDA % 17 17 17 Cata ppm 0 2500 5000 Total 100 100 100

[0208] [Tables5] T2 B1 B2 PGS % 71 71 71 BPADA % 29 29 29 Cata ppm 0 2500 5000 Total 100 100 100 • Methylsulfonic acid#

[0209] [Tableauxô] Tl Cl C2 PGS % 83 83 83 BTDA % 17 17 17 Cata ppm 0 2500 5000 Total 100 100 100

[0210] [Tables?] T2 DI D2 PGS % 71 71 71 BPADA % 29 29 29 Cata ppm 0 2500 5000 Total 100 100 100

[0211] 2.2. Protocol for the preparation of crosslinked polyesters Step a)

[0212] Place a 100mL beaker on a hot plate equipped with a PT100 probe to control the temperature.

[0213] Introduce the poly(glycerol sebacate).

[0214] Heat the polymer to 50°C while mixing it with a spatula.

[0215] Add the quantity of bis anhydride.

[0216] In another method of preparation, add the quantity of sulfonic acid compound in the different proportions.

[0217] Mix with a spatula until a homogeneous mixture is obtained.

[0218] Cool to room temperature. Step b)#: crosslinking

[0219] Crosslinking is carried out at 140°C in the MCR rheometer during the measurement of the crosslinking kinetics according to the method described above in point 1.2. Crosslinking within the framework of this test protocol corresponds to obtaining a crosslinked polyester having an elastic modulus of value of IMPa.

[0220] 2.3. Characterization of the crosslinking rates of polyesters • Time to obtain a polyester crosslinked with para-toluene acid sulfonic acid#

[0221] [Tables8] Tl Al A2 Tests t at 140°C (min) 167 80 60

[0222] [Tables 9] Tests T2 B1 B2 t at 140°C (min) 150 120 100

[0223] • Time to obtain a polyester crosslinked with methyl sulfonic acid # [Tables 10] Tests T1 Cl C2 t at 140°C (min) 167 95 120

[0224] [Tables 11] Tests T2 DI D2 t at 140°C (min) 150 125 130 3. Discussion

[0225] A very significant reduction in crosslinking time is observed for all compositions according to the invention in that they comprise the polyanhydride compound with the sulfonic acid compound in the different proportions and natures tested.

Claims

Demands

1. A process for preparing a crosslinked glycerol polyester and a dicarboxylic acid monomer, comprising a step of crosslinking a glycerol polyester and a dicarboxylic acid monomer with a cyclic carboxylic polyanhydride A in the presence of a sulfonic acid compound, the cyclic carboxylic polyanhydride A comprising at least two cyclic carboxylic anhydride groups, the cyclic carboxylic polyanhydride A not comprising a linear carboxylic anhydride group.

2. A process according to claim 1, wherein the dicarboxylic acid monomer has the formula [HOOC-(CH2)P-COOH], in which p is a number from 1 to 30, preferably a number from 1 to 10, advantageously sebacic acid (p=8).

3. A method according to claim 1 or 2, wherein the cyclic carboxylic anhydride groups of the cyclic carboxylic polyanhydride A are independently selected from ortho phthalic, succinic, maleic, homo phthalic and isatoic groups.

4. A method according to any one of the preceding claims, wherein the cyclic carboxylic anhydride groups of the cyclic polycarboxylic anhydride A are joined, linked together by at least one covalent bond or linked by a spacer group L, L representing -O-; -S-; -S(O)-; -S(O)2-; -C(O)-; -NRnRn- with Rn and Rn- independently selected from H or a Ci-C6 alkyl group, or a multivalent hydrocarbon group comprising 1 to 40 carbon atoms, cyclic or acyclic, saturated, unsaturated or aromatic, and able to contain one or more heteroatoms of O, S, Cl, Br, F, N, P or Si, L being devoid of linear anhydride groups.

5. A process according to any one of the preceding claims, wherein the cyclic carboxylic polyanhydride A comprises or is a compound of formula (I) or (II): OO (I) or o O (H) X ..-x Lv A Jl ..---x À 1 11 U i U. XA 1* 1 I ce Y' "XX " o O"'"' Y'' in which Li represents a bond; -O-; -S-; -S(O)-; -S(O)2-; -NRnRn- with Rn and Rn- independently chosen from H or an alkyl group in Ci -C6; -C(O)-; or an aliphatic chain of 1 to 30 carbon atoms, wherein 1 to 6 methylene unit(s) is / are optionally replaced by an arylene group, a heteroarylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-, -NRm- with Rm selected from H or a Ci-C6 alkyl group, -P-, -P(O)-, -SiRaRb- with Ra and Rb independently representing an -OH, Ci-C6 alkyl or Ci-C6 alkoxy group, said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two CrC6 alkyl, Ci-C6 alkoxy, hydroxyl, nitro, cyano, halogen, Ci-C6 haloalkyl, Zi is absent or represents a -CH2- (methylene) or -NH- group, Z2 is absent or represents a -CH2- (methylene) or -NH- group, X independently represents a C6-alkyl group, a C6-hydroxyl, C6-alkoxy, nitro, cyano, or halogen atom, n represents an integer from 0 to 3, preferably from 0 to 2, Y independently represents a C6-alkyl group, a C6-hydroxyl, C6-alkoxy, nitro, cyano, or halogen atom, m represents an integer from 0 to 3, preferably from 0 to 2, Ai represents: - a C-C bond or a C=C bond linking the four carbon atoms of the two carboxylic anhydride functions, - a saturated, unsaturated or aromatic carbocycle, optionally bridged, said carbocycle comprising from 4 to 30 carbon atoms, or - a saturated, unsaturated or aromatic heterocycle, optionally bridged, said heterocycle comprising from 4 to 30 carbon atoms, and said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents selected from a Ci-C6 alkyl group, a Ci-C6 hydroxyl, alkoxy, nitro, cyano, or halogen atom.

6. A process according to any one of the preceding claims wherein the sulfonic acid compound is para-toluenesulfonic acid, benzenesulfonic acid, para-dodecylbenzenesulfonic acid, methylsulfonic acid or ethylsulfonic acid.

7. A process according to any one of the preceding claims, wherein the crosslinking step comprises the following steps: (a) contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid monomer with 0.1 to 200 parts by weight of at least one cyclic polycarboxylic anhydride as defined in any one of claims 3 to 5, in the presence of 0.0001 wt% (0.1 ppm) to 1 wt% (1000 ppm) relative to the mass of the polyester of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound; (b) pressurizing the mixture obtained in the crosslinking precursor step of step a) to a target temperature Tc between 60°C and 175°C, and holding at temperature Tc and under pressure for a heating time Tc sufficient to obtain a polyester crosslinked, (c) cooling and recovery of the crosslinked polyester.

8. A method according to claim 7, wherein step a) comprises contacting 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid, with 10 to 100 parts by weight of at least one cyclic polycarboxylic anhydride.

9. A process according to claim 7 or 8, wherein step a) comprises the use of 0.05 wt% (500ppm) to 1 wt% (1000ppm), preferably from 0.1 wt% (1000ppm) to 0.9 wt% (9000ppm), relative to the polyester mass of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound.

10. A method according to any one of claims 7 to 9, wherein the temperature Tc is between 80°C and 160°C.

11. Crosslinking composition, comprising: - 100 parts by weight of at least one polyester of glycerol and a dicarboxylic acid monomer, - from 0.1 to 200 parts by weight of at least one cyclic carboxylic polyanhydride as defined in any one of claims 3 to 5, - from 0.0001% mass (0.1 ppm) to 1% mass (1000 ppm) relative to the mass of polyester of glycerol and a dicarboxylic acid monomer, of a sulfonic acid compound.

12. Composition according to claim 11, wherein the dicarboxylic acid monomer has the formula [HOOC-(CH2)P-COOH], in which p is a number from 1 to 30, preferably a number from 1 to 10, advantageously sebacic acid (p=8).

13. Composition according to claim 11 or 12, wherein the polyester of glycerol and a dicarboxylic acid monomer has a number-average molar mass Mn less than or equal to 10,000 g / mol.

14. Composition according to any one of claims 11 to 13, wherein the cyclic carboxylic polyanhydride comprises a compound of formula (I) or (II): O 0 (I) or o O (H) A Lf- ..-x X 1. . Jl oyo o' 'y . y '0 YUY,. À À L slk o'" Y" 'Y 'zi ''O a--' "zA---'" <y>(Y :a}rs in which Li represents a bond ; -O- ; -S- ; -S(O)- ; -S(O)2- ; -NRnRn- with Rn and Rn- independently chosen from H or a Ci-C6 alkyl group ; -C(O)- ; or an aliphatic chain of 1 to 30 carbon atoms, in which 1 to 6 methylene unit(s) is / are optionally replaced by an arylene group, a heteroarylene group, -C(O)-, -O-, -S-, -S(O)-, -S(O)2-, -NRm- with Rm chosen from H or a Ci-C6 alkyl group, ;-P-, -P(O)-, -SiRaRb- with Ra and Rb independently representing a -OH, Ci-C6 alkyl or Ci-C6 alkoxy group, said aliphatic chain being substituted or unsubstituted by one or more, in particular one or two CrC6 alkyl, Ci-C6 alkoxy, hydroxyl, nitro, cyano, halogen atom, Ci-C6 haloalkyl group(s), Zi is absent or represents a -CH2- (methylene) or -NH- group, Z2 is absent or represents a -CH2- (methylene) or -NH- group, X independently represents a Ci-C6 alkyl, hydroxyl, Ci-C6 alkoxy, nitro, cyano, or halogen atom; n represents an integer from 0 to 3, preferably from 0 to 2. Y represents, independently of each other, a C6-alkyl group, a C6-hydroxyl, a C6-alkoxy, nitro, cyano, or halogen atom. m represents an integer from 0 to 3, preferably from 0 to 2. Ai represents: - a C-C bond or a C=C bond linking the four carbon atoms of the two carboxylic anhydride functions, - a saturated, unsaturated, or aromatic carbocycle, optionally bridged, said carbocycle comprising from 4 to 30 carbon atoms, or - a saturated, unsaturated, or aromatic heterocycle, optionally bridged, said heterocycle comprising from 4 to 30 carbon atoms, and said carbocycle or heterocycle being substituted or unsubstituted by one or more substituents selected from a C6-alkyl group, a C6-hydroxyl, a C6-alkoxy, nitro, cyano, or halogen atom. Ci-C6, nitro, cyano, or halogen atom.

15. Composition according to any one of claims 11 to 14, wherein the sulfonic acid compound is selected from para-toluenesulfonic acid, benzenesulfonic acid, para-dodecylbenzenesulfonic acid, methylsulfonic acid or ethylsulfonic acid.< / y>