METHOD FOR PREPARING A THERMOPLASTIC POLYURETHANE IN A MELTED MEDIUM

Abstract

The present invention relates to a process for preparing a thermoplastic polyurethane (TPU) in a molten medium, with a high bio-based content, particularly from bio-based aromatic diisocyanates. The present invention also relates to bio-based aromatic diisocyanates, their preparation process, and their uses. (no figure)

Description

Title of the invention: METHOD FOR PREPARING A THERMOPLASTIC POLYURETHANE IN A MELTED MEDIUM

[0001] The present invention relates to a process for preparing a thermoplastic polyurethane (TPU) in a molten medium, with a high bio-based content, particularly from bio-based aromatic diisocyanates. The present invention also relates to bio-based aromatic diisocyanates, their preparation process, and their uses.

[0002] Thermoplastic polyurethanes (TPUs) are flexible, non-crosslinked polymers used in various sectors, including automotive (seat upholstery), sports (shoe soles), and medicine (drainage tubing). Like crosslinked polyurethanes (PUs), they are obtained from petroleum-based isocyanates and polyols, which have a significant environmental and health impact due to the use of phosgene (a highly toxic gas) in the isocyanate synthesis process.

[0003] Increasing the proportion of bio-based materials in polyurethanes represents a promising step forward in reducing their environmental impact while meeting the performance requirements of various industrial applications. To achieve this, it is necessary to have bio-based precursors that are equivalent to petroleum-based precursors and less harmful than those currently used. Today, the introduction of bio-based materials into commercial PUs is limited to the incorporation of a small fraction of polyols (for example, derived from soy). However, there are no commercially available bio-based aromatic diisocyanates that can effectively replace current diisocyanates, such as diphenylmethylene 4,4'-diisocyanate (4,4'-MDI) and its derivatives, or toluene diisocyanate (TDI).

[0004] And the introduction of bio-based material into PUs generally takes place during syntheses using organic solvents, which is not desirable from an industrial point of view, nor from an ecological and environmental point of view.

[0005] One objective of the invention is thus to make available bio-based thermoplastic polyurethanes (i.e. with a high bio-based content), from aromatic diisocyanates which are themselves bio-based, and of generation > 2 (i.e. not competing with the agri-food sector).

[0006] Another objective of the invention is to provide these thermoplastic polyurethanes using a solvent-free process, from diisocyanates allowing their use in a melt synthesis, while exhibiting a chemical reactivity identical to that of petroleum-based commercial references such as 4,4'-MDI.

[0007] Another objective of the invention is to provide these aromatic diisocyanates using a phosgene-free synthetic route, from bio-based aromatic molecules.

[0008] By “bio-based”, we mean in particular derived from renewable organic matter, of microbial, plant, fungal or animal origin, in particular plant.

[0009] Thus, the invention relates to a process for preparing a thermoplastic polyurethane (TPU) in a molten medium, comprising the following steps: i. A step of bringing at least one diisocyanate (A) and at least one diol (B) into contact; ii. A step of bringing the composition obtained in the previous step into contact with at least one catalyst (C) and at least one chain-extending compound (D);

[0010] the diisocyanate (A) having the following formula (Io): P' OCN X^NCO (Ar V j 'LX-. .-X. H w■ R2 R a

[0011] in which:

[0012] Ar and Ar' are independently chosen from among the aryls, in particular being a phenyl or a naphthyl, in particular a phenyl;

[0013] Ri, R' i, R2 and R'2 are independently selected from hydrogen and linear, branched or cyclic O-(Ci-C8)-alkyl groups, in particular a methoxyl group (OMe);

[0014] L is a linear, branched or cyclic diyl (C3-C20)-alkane.

[0015] According to a particular embodiment, Ar and Ar' are identical, in particular being a phenyl or a naphthyl.

[0016] According to a particular embodiment, the diisocyanate (A) has the following formula (I): r R' OCN. ^,«1 Vx „NCO y 4O-L-O4 H r2 R'2

[0017] According to a particular embodiment, the diisocyanate (A) has the following formula (I-1): OCN R'i 1 ) ' 'OL-CT X' R2 RC

[0018] According to a particular embodiment: - Ri and R' i are identical, and / or - R2 and R'2 are identical.

[0019] According to a particular embodiment, Rb R' b R2 and R'2 represent OME.

[0020] According to a particular embodiment: - Ri and R' i represent OME, and / or - R2 and R'2 represent H.

[0021] According to a particular embodiment, Rb R' b R2 and R'2 represent H.

[0022] According to a particular embodiment, the diisocyanate (A) has the formula (1-2) next: NCO NCO XA " ■ G" ' G , o "

[0023] According to a particular embodiment, the diisocyanate (A) has the following formula (1-3): (1-3). '■f' • >—i — C> ' <■' HCO

[0024] According to a particular embodiment, L is a linear, branched or cyclic diyl (C3-C8)-alkane or a linear, branched or cyclic diyl (C3-Ci2)-alkane.

[0025] According to a particular embodiment, L is a linear (C3-C5)-diyl alkane.

[0026] According to a particular embodiment, Rb R' b R2 and R'2 represent OME, and L is a linear, branched or cyclic diyl (C3-C8)-alkane, in particular a linear diyl (C3-C5)-alkane.

[0027] According to a particular embodiment: - Ri and R' i represent OME, and / or - R2 and R'2 represent H,

[0028] and L is a linear, branched or cyclic diyl (C3-C8)-alkane, in particular a linear diyl (C3-C5)-alkane.

[0029] According to a particular embodiment, Rb R' b R2 and R'2 represent H, and L is a linear, branched or cyclic diyl (C3-C8)-alkane, in particular a linear diyl (C3-C5)-alkane.

[0030] According to a particular embodiment, the diol (B) is chosen from polyether polyols, in particular polyether polyols with a molar mass of 100 to 2000 g / mol.

[0031] According to a particular embodiment, the diol (B) is chosen from polyether polyols, in particular bio-based polyether polyols with a molar mass of 100 to 2000 g / mol.

[0032] These polyether polyols are typically derived from propanediol (PDO). Examples include polyether polyols marketed under the name Velvetol®, particularly under the references H250, H500 and H1000.

[0033] The catalyst is a catalyst for the (coupling) reaction between a hydroxyl group and an isocyanate group, as is well known to those skilled in the art.

[0034] By way of example, such catalysts may be tertiary amines, tin chloride, organometallic compounds such as metal acetonyl acetates, tin organometallic compounds, calcium hexanoate, calcium 2-ethylhexanoate, calcium octanoate and calcium linoleate, dibutyltin dilaurate (DBTDL, CAS: 75-58-7), bismuth tris(2-ethylhexanoate) and zinc bis(2-ethylhexanoate), sulfonimides, such as bis(trifluoromethane)sulfonimide (TFMI, CAS: 82113-65-3), sulfonic acids, such as trifluoromethanesulfonic acid (triflic acid), p-toluenesulfonic acid (PTSA, CAS: 104-15-4) and acid methanesulfonic acid (MSA, CAS: 75-75-2), phosphate derivatives, such as diphenyl phosphate (DPP, CAS: 838-85-7).

[0035] For example, the catalyst is chosen from dibutyltin dilaurate (DBTDL), bis(trifluoromethane), triflic acid, p-toluene sulfonic acid (PTSA), methanesulfonic acid (MSA) and diphenyl phosphate (DPP).

[0036] According to a particular embodiment, the catalyst is dibutyltin dilaurate (DBTDL).

[0037] According to a particular embodiment, the catalyst (C) is selected from among the tertiary amines, in particular from the group consisting of triethylamine, tributylamine, N,N-dimethylcyclohexylamine, dimethylbenzylamine, N,N'-dimethylpiperazine, N,N,N,N-tetramethylpropane-1,3-diamine, bis(2-dimethylaminoethyl)ether, 2-dimethylaminoethyl-3-dimethylaminopropyl ether, N-methylmorpholine, N-ethylmorpholine, N-methoxyethylmorpholine, 2,2'-dimorpholinodiethyl ether (DMDEE), bis(2,6-dimethylmorpholinoethyl)ether, bis(3,5-dimethylmorpholinoethyl)ether, N,N-dimethylphenylamine, N,N, N,N-tetramethylbutane-1,3-diamine, N,N,N,N-tetramethylpropane-1,3-diamine, N,N,N,N-tetramethylhexane-1,6-diamine, 1-methyl imidazole, 2-methyl-1-vinyl imidazole, 1-allyl imidazole, 1-phenyl imidazole, 1,2,4,5-tetramethyl imidazole, pyrimidazole, 4-dimethylaminopyridine, 4-pyrrolidinopyridine,of 4-morpholinopyridine, 4-methylpyridine, N-decyl-2-methyl imidazole, N-dodecyl-2-methyl imidazole, tris(dimethylaminopropyl) hexahydrotriazine, tetramethylguanidine, l,8-diazabicyclo[5.4.0]-7-undecene, (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), quinuclidine, bis-dimethylaminomethyl phenol, 2-(2-dimethylaminoethoxy)-ethanol, quinuclidinol, hydroxymethyl quinuclidinol, and mixtures thereof.

[0038] In particular, the tertiary amines are selected from 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 2,2'-dimorpholinodiethyl ether (DMDÉE), 1,4-diazabicyclo[2.2.2]octane (DABCO), and mixtures thereof.

[0039] Preferably the catalyst (C) is 1,4-diazabicyclo[2.2.2]octane (DABCO).

[0040] According to a particular embodiment, the chain-extending compound (D) comprises two hydroxyl groups, having a molar mass of less than 200 g / mol.

[0041] According to a particular embodiment, the chain-extending compound (D) is a butanediol, in particular 1,4-butanediol, or a propanediol, in particular 1,2-propanediol.

[0042] According to a particular embodiment, at least one diisocyanate (A) is used in the absence of other diisocyanates.

[0043] According to a particular embodiment, at least one diisocyanate (A) is used in the presence of at least one other diisocyanate.

[0044] Said at least one other diisocyanate may be chosen from among the diisocyanates well known to the person skilled in the art, in particular from among the commercial diisocyanates.

[0045] This may, for example, be diphenylmethylene 4,4'-diisocyanate (4,4'-MDI) and toluene diisocyanate (TDI).

[0046] According to a particular embodiment, at least one diisocyanate (A) is used in the presence of at least one other diisocyanate, at a level of approximately 5 to 50% by mass relative to the total mass of diisocyanate, for example from approximately 10, 15 or 20 to 50%.

[0047] According to a particular embodiment, at least one diisocyanate (A) and / or at least one diol (B) are bio-based.

[0048] According to a particular embodiment, step (i) and / or step (ii) are carried out in the absence of solvent.

[0049] According to a particular embodiment, the process of the invention is carried out in the absence of solvent.

[0050] According to a particular embodiment, the process of the invention is carried out under agitation.

[0051] According to a particular embodiment, step (i) is carried out in particular under agitation: - at a temperature of 50 to 150°C, in particular from about 80 to about 100°C; - at a pressure ranging from 0.1 mbar to 1 bar, for example at approximately 200 mbar; and / or - for a period of 10 to 120 minutes, for example for about 45 minutes.

[0052] According to a particular embodiment, step (i) is carried out under an inert atmosphere, for example under nitrogen or argon.

[0053] According to a particular embodiment, the molar ratio diisocyanate (A) / diol (B) is between 1 and 5, in particular between 2 and 3.

[0054] According to a particular embodiment, the amount of compound (C) is from 10 to 500 molar % of the amount of diol (B), in particular about 500 molar % of the amount of diol (B).

[0055] According to a particular embodiment, the quantity of compound (D) is from 0.001 to 5 molar % of the complete formula, in particular from 0.01 to 1%, more particularly from about 0.06%.

[0056] This quantity can be easily adapted according to the nature of the compound (D), as is well known to those skilled in the art.

[0057] By "complete formula" is meant in particular the assembly consisting of at least one diisocyanate (A), at least one diol (B), at least one catalyst (C) and at least one chain-extending compound (D).

[0058] According to a particular embodiment, step (ii) comprises: - A substep (iii) of mixing the compounds as defined above; - A substep (ii2) of heating the mixture obtained in the previous step.

[0059] According to a particular embodiment, step (ii) or (ii2) is carried out under stirring.

[0060] According to a particular embodiment, step (ii) or (ii2) is carried out in particular under hustle : - at a temperature between 50 and 150 °C, in particular from about 80 to about 100 °C; - at a pressure between 0.1 mbar and 1 bar, for example at approximately 200 mbar; and / or - for a period of 5 seconds to 5 minutes, in particular from about 30 to about 60 seconds.

[0061] The reagents mentioned above, in particular the diol (B) and the chain extender (D), can be dried prior to their use, as is well known to those skilled in the art, for example at 100 °C overnight.

[0062] According to another aspect, the invention also relates to a thermoplastic polyurethane that can be obtained by a process as defined above.

[0063] All embodiments defined previously with respect to polyurethane also apply here, alone or in combination.

[0064] According to another aspect, the invention also relates to the use of a thermoplastic polyurethane as defined above in a field such as the automotive industry, for example for the preparation of seat coverings, sports, for example for the preparation of shoe soles, and medicine, in particular for the preparation of drainage tubes.

[0065] All embodiments defined previously with respect to polyurethane also apply here, alone or in combination.

[0066] According to another aspect, the invention also relates to a compound (A) of the following formula (II): (H), OCN t R V-^NCO QAr)-O”L~o4 X «S

[0067] in which:

[0068] Ar and Ar' are independently chosen from among the aryls, in particular being a phenyl or a naphthyl, in particular a phenyl;

[0069] Ri, R' i, R2 and R'2 are independently selected from hydrogen and linear, branched or cyclic O-(CrC8)-alkyl groups, in particular a methoxyl group (OMe);

[0070] L is a linear, branched or cyclic diyl (C3-C20)-alkane,

[0071] said compound not having the following (1-1) formula: OCN.. ..Rs RV.x ,NCO s-- xA, Ax Y OH-O' Ri «2

[0072] with:

[0073] Ri, R'i being linear, branched or cyclic O-(CrC8)-alkyl groups, in particular a methoxyl group (OMe); and

[0074] R2 and R'2 being chosen from hydrogen and linear, branched or cyclic O-(Ci-C8)-alkyl groups, in particular a methoxyl group (OMe); and

[0075] L being a linear (C3-C5)-diyl alkane.

[0076] All embodiments defined previously with respect to diisocyanate (A) of formula (Io) and following also apply here, alone or in combination.

[0077] According to a particular embodiment, the invention relates to a compound (A) of formula (II) as defined above, in which: - L is a linear, branched or cyclic diyl (C8-C20)-alkane, in particular is a linear, branched or cyclic diyl (C10-C20)- or (Ci2-C2o)-alkane;

[0078] and / or - Rb R' 1, R2 and R'2 represents hydrogen, said compound having in particular the following formula (1-2): (1-2). NCO NCO

[0079] or of the following formula (1-3): OCN^ (H)' NCO

[0080] Compounds of formula (II) have an advantageous melting point.

[0081] For example, a compound of formula (II) according to the invention: - has a melting point of 77 °C, when said compound is of formula (1-1) with Rb R'b R2 and R'2 representing OME and L being a linear diyl (Ci2)-alkane; - is liquid at room temperature, when said compound is of formula (1-3) with L being a linear (C3)-diyl alkane.

[0082] According to another aspect, the invention also relates to a process for preparing a compound (A) as defined above, which comprises the following steps: a. A step of protecting the carboxyl group of compounds Ai by esterification of the following formulas: (HO 4 Ad R, HS

[0083] to obtain the corresponding protected A2 compounds, in particular using methanol, for example in the presence of a strong acid, in particular sulfuric acid; a. A step of contacting the compounds A2 as obtained in the previous step with a compound of formula XL-X' in which X and X' are leaving groups, for example a halogen, in particular Br, and L is as defined previously, to obtain a dimeric compound A3, for example in the presence of potassium carbonate; b. A step of deprotection of the esters, into corresponding carboxylic acids, of the dimer compound A3 obtained in the previous step for to obtain a deprotected A4 compound, in particular with the help of methanol, for example in the presence of a strong base, in particular sodium hydroxide; c. A step of transformation of the carboxyl groups of compound A4 into acyl azides, for example by reaction with triethylamine, ethylchloroformate and sodium azide; d. A step of transformation of the acyl azide groups of compound A5 obtained in the previous step to generate isocyanate groups, in particular by heat treatment, in particular by Curtius rearrangement.

[0084] All embodiments defined previously with respect to polyurethane also apply here, alone or in combination.

[0085] If the compound (A) is symmetric, the process as described above relates to the use of a single compound Ai as defined above. DEFINITIONS

[0086] As understood here, value ranges in the form of "xy" or "from x to y" or "between x and y" include the bounds x and y, the integers between these bounds, and all other real numbers between these bounds. For example, "1-5", or "from 1 to 5", or "between 1 and 5" refers to the integers 1, 2, 3, 4, and 5, as well as all other real numbers between 1 and 5. Preferred embodiments include each individual integer within the value range, as well as any subcombination of these integers and any set of real numbers between these integers. As an example, preferred values ​​for "1-5" may include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, etc.

[0087] As used in this description, the term "approximately" refers to a range of values ​​within ±10% of a specific value. For example, the expression "approximately 20" includes values ​​within 20 ±10%, that is, values ​​from 18 to 22. FIGURES

[0088] Fig. 1 shows the reaction kinetics of 4,4'-MDI and a bio-based aromatic diisocyanate synthesized from syringic acid and 1,3-dibromopropane, according to Example 1, placed in the presence of propanol and 1%mol of DABCO, measured by 1H NMR spectroscopy at 80 °C (400 MHz, Toluene-d8), according to Example 2.

[0089] Fig. 2 relates to the tensile comparison of the mechanical properties of TPUs with different levels of bio-based isocyanate, according to example 4. EXAMPLES

[0090] Example 1: Synthesis of bio-based aromatic diisocyanates

[0091] The synthesis route for the bio-based aromatic diisocyanates of the invention consists of 5 successive steps:

[0092] Step 1: Protection of the carboxyl groups of a phenolic derivative (e.g. syringic acid, vanillic acid, salicylic acid, anisic acid, 3-hydrobenzoic acid) in methanol in the presence of concentrated sulfuric acid, for 16h under reflux.

[0093] Step 2: Dimerization of the ester obtained using a dibromoalkane of optimized structure, and potassium carbonate, in dimethylformamide at 100°C for 16h.

[0094] Step 3: Deprotection of carboxyl groups in refluxing methanol for one day in the presence of sodium hydroxide.

[0095] Step 4: Transformation of carboxyl groups into acyl azides by reaction with triethylamine, ethylchloroformate and sodium azide in a THF:water (75:25) mixture at 0°C for 8h.

[0096] Step 5: Heat treatment of acyl azide to generate isocyanate groups in an inert atmosphere by Curtius rearrangement in anhydrous toluene at 80°C for 8h.

[0097] The diagram below shows an example of the synthesis of a bio-based diisocyanate from syringic acid, according to the steps above: x*' Aœture itXylé | S ( «0^ * A, y'8**1

[0098] The choice of the initial phenolic derivative, and of a suitable dibromoalkane during step 2, as defined above, makes it possible to significantly modulate the melting temperature of the aromatic diisocyanate obtained at the end of step 5. For example, the use of syringic acid and 1,3-dibromopropane makes it possible to synthesize a diisocyanate having a melting temperature of 102.3 °C, which can be easily used for TPU syntheses in the melt process at 100 °C.

[0099] Example 2: Comparison of the reactivity of bio-based aromatic diisocyanates synthesized without phosgene, according to the invention, with that of conventional petroleum-based 4,4'-MDI

[0100] The reactivity of a bio-based aromatic diisocyanate according to the invention, synthesized according to Example 1, was compared to that of petroleum-based 4,4'-MDI to evaluate its impact on TPU synthesis times. The tests were carried out in deuterated toluene solution in the presence of 1.1 equivalents of propanol and 1 mol% of DABCO catalyst. The reaction kinetics were monitored in situ by NMR at 80 °C for 3 hours. The progress of the reaction was calculated based on the appearance of new peaks corresponding to methanes and the decrease in peaks corresponding to isocyanates. Equivalent reactivities were observed between the petroleum-based isocyanate (reference) and the bio-based one synthesized according to the invention.

[0101] Example 3: Synthesis of bio-based TPUs according to the invention

[0102] The diol (eg H1000) and the chain extender (eg 1,2-propanediol) are dried at 100°C overnight.

[0103] Next, the diol (25 mmol) and the diisocyanate(s) (50 mmol) (bio-based diisocyanate used alone or in a mixture with other bio-based or petroleum-based diisocyanates) are mixed at 200 mbar and under an inert atmosphere in a reactor for 45 min at 100°C.

[0104] The catalyst (DBTDL, 0.0285 mmol) and the chain extender (1,2-propanediol, 25 mmol) are then introduced into the mixture. After 1 minute, the mixture is stopped and post-curing is carried out in an oven at 110°C overnight.

[0105] The tests were carried out with different proportions of bio-based diisocyanate, mixed with 4,4'-MDI (from 0% to 100%). The TPU with 0% bio-based diisocyanate contains 68.24% bio-based material, while the one composed solely of bio-based diisocyanate reaches 99.96%.

[0106] Thus, in this context, the proportion of bio-based material will be between 68 and 100%, regardless of the rate of bio-based diisocyanate incorporated.

[0107] Under these conditions, the synthesized TPU is soluble in conventional organic solvents (e.g. CHC13, THF), and therefore not crosslinked.

[0108] Characterization by 1H NMR spectroscopy clearly shows the formation of TPU with the disappearance of the peaks corresponding to the protons of the aromatic rings of the isocyanate precursors and the appearance of new peaks associated with the protons of the aromatics now linked to the methanes. Example 4#: Characterization of bio-based TPUs

[0109] The mechanical properties of TPUs with different levels of bio-based isocyanate were compared by tensile testing. The tests were carried out on pre-prepared specimens pressed at 120°C for 5 minutes. A decrease in maximum stress is observed as the bio-based isocyanate content increases. This phenomenon can be mitigated, if desired, by using a diol with a lower molar mass, particularly a polyether diol with a molar mass below 1000 g / mol (for example, H500 or H250).

Claims

Demands

1. A process for preparing a thermoplastic polyurethane (TPU) in a molten medium, comprising the following steps: i. A step of contacting at least one diisocyanate (A) and at least one diol (B); ii. A step of contacting the composition obtained in the previous step with at least one catalyst (C) and at least one chain-extending compound (D); the diisocyanate (A) being of the following formula (Io): R' (Io)' OCN 4^NC0 ( Ar in which: Ar and Ar' are independently chosen from among the aryls, in particular a phenyl or a naphthyl, in particular a phenyl; Ri, R'i, R2 and R'2 are independently chosen from among hydrogen and linear, branched or cyclic O-(Ci-C8)-alkyl groups, in particular a methoxyl (OMe) group; L is a linear, branched or cyclic diyl (C3-C20)-alkane.

2. A method according to claim 1, wherein Ar and Ar' are identical, in particular being a phenyl or a naphthyl,

3. A method according to claim 1, wherein L is a linear, branched or cyclic diyl (C3-Ci2)-alkane, in particular a linear diyl (C3-C5)-alkane.

4. A method according to any one of the preceding claims, wherein the diol (B) is selected from polyether polyols, in particular bio-based polyether polyols with a molar mass of 100 to 2000 g / mol.

5. A method according to any one of the preceding claims, wherein the chain-extending compound (D) comprises two hydroxyl groups, having a molar mass of less than 200 g / mol, the chain-extending compound (D) being in particular a butanediol, especially 1,4-butanediol, or a propanediol, especially 1,2-propanediol.

6. A method according to any one of the preceding claims, which is carried out in the absence of solvent.

7. A method according to any one of the preceding claims, wherein step (i) is carried out: - at a temperature of 50 to 150°C; - at a pressure of 0.1 mbar to 1 bar, in particular under vacuum; and / or - for a period of 10 to 120 min.

8. A method according to any one of the preceding claims, wherein step (ii) is carried out: - at a temperature of 50 to 150°C; - at a pressure of 0.1 mbar to 1 bar; and / or - for a duration of 5 s to 5 min.

9. Compound of the following formula (II): { Arj-O-LOi AT) "" pç ““ wherein: Ar and Ar' are independently selected from the aryls, in particular being a phenyl or a naphthyl, in particular a phenyl; Ri, R'i, R2 and R'2 are independently selected from hydrogen and linear, branched or cyclic O-(Ci-C8)-alkyl groups, in particular a methoxyl group (OMe); L is a linear, branched or cyclic (C3-C20)-alkane diyl, said compound not being of the following formula (1-1): (1-1), OCN R'i s NCO R; R'z with: Ri, R'i being linear, branched or cyclic O-(Ci-C8)-alkyl groups, in particular a methoxyl group (OMe); and R2 and R'2 being chosen from hydrogen and linear, branched or cyclic O-(Cr C8)-alkyl groups, in particular a methoxyl (OMe) group; and L being a linear (C3-C5)-diyl alkane.

10. Compound according to claim 9 of formula (II) wherein: - L is a linear, branched or cyclic diyl (C8-C20)-alkane, in particular is a linear, branched or cyclic diyl (Ci0-C20)- or linear, branched or cyclic diyl (Ci2-C20)-alkane; and / or Rb R'i, R2 and R'2 represent hydrogen.

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