Vitrimmer with a wide processing window

Abstract

The present invention relates to a method for synthesizing a single ester-containing benzoxazine monomer, comprising the steps of (i) reacting a phenolic carboxylic acid with a phenol compound containing at least one hydroxyl group at a temperature of 25°C to 200°C for 1 to 72 hours in the presence of a Brønsted acid-type catalyst to obtain a phenol-terminated oligomer or molecule, and (ii) reacting the phenol-terminated oligomer or molecule with a mixture of an amino alcohol, a formula primary amine, and paraformaldehyde at a temperature in the range of 50°C to 150°C for 1 to 10 hours with stirring to obtain a single ester-containing benzoxazine monomer. [Case 1] JPEG2026521571000028.jpg4192

Description

[Technical Field]

[0001] This invention relates to the field of benzoxazine derivative vitrimers with a wide processing window, methods for producing the same, and the use of the vitrimers in various applications. [Background technology]

[0002] Vitrimers are polymeric materials that, due to the dynamic properties of their covalent network structure resulting from reversible chemical bonding, allow materials to be repaired, recycled, and reprocessed like thermoplastics. These exchange reactions are triggered by external stimuli, most frequently temperature. The viscosity of vitrimers gradually decreases upon heating, giving the network structure malleability while relieving internal stresses. The integrity of the network structure across the entire range of applications ensures mechanical and solvent resistance.

[0003] Dynamic transesterification reactions have attracted considerable interest over the past decade, following a prototype vitrimer developed by Leibler et al. in 2011 (D. Montarnal, M. Capelot, F. Tournilhac, and L. Leibler, Science, 2011, pp. 334, 965-968). These chemical exchanges, induced between ester bonds and hydroxyl groups at high temperatures, are responsible for topological rearrangement. Transesterification mechanisms have been implemented in crosslinked network structures to design self-healing, recyclable, and reworkable materials with tunable properties.

[0004] Demongeot et al. (A. Demongeot, R. Groote, H. Goossens, T. Hoeks, F. Tournilhac, and L. Leibler, Macromolecules, 2017, 50(16), pp. 6117-6127) adapted the concept of vitrimers to commercially available thermoplastics. Crosslinked polybutylene terephthalate (PBT) vitrimers based on transesterification were successfully prepared by reactive extrusion. In addition to improving the manufacturing techniques and the range of possible network structures, the global environmental protection situation is calling on the scientific community to promote sustainable polymers derived from naturally occurring raw materials. Altuna et al. (FI Altuna, V. Pettarin, and R. Williams, Green Chem., 2013, 15, pp. 3360-3366) attempted to produce a completely bio-based polyester exhibiting properties reminiscent of vitrimers, starting from epoxidized soybean oil and an aqueous citric acid solution. Furthermore, Legrand et al. (A. Legrand and C. Soulie-Ziakovic, Macromolecules, 2016, 49, pp. 5893-5902) have expanded the scalability of the application of vitrimer reticular structures by developing silica-reinforced epoxy vitrimer nanocomposites with enhanced properties.

[0005] Polybenzoxazines are a novel type of thermosetting resin with outstanding mechanical and thermal properties. Like many other thermosetting resins, they cannot be remolded, reprocessed, or recycled. A few examples showing a reasonable level of repairability have been reported (L. Zhang, Z. Zhao, Z. Dai, L. Xu, F. Fu, T. Endo, X. Liu, ACS Macro. Lett. 2019, 8, 5, pp. 506-511 and Arslan M., Kiskan B., Y. Yagci, Sci. Rep. 2017, 7, 5207).

[0006] The applicant has shown that several different chemical structures of polybenzoxazine type vitrimers exhibit, in particular, self-healing, reformability, reworkability, high strength, and low melt viscosity due to the benzoxazine portion of the starting monomer used to produce the corresponding vitrimer by polymerization. WO 2021 / 180562 A1 relates to vitrimers obtained by polymerization of disulfide-containing benzoxazine monomers. WO 2022 / 122735 A1, WO 2021 / 250024, and WO 2023 / 057568 A1 relate to vitrimers obtained by polymerization of diester-containing benzoxazine monomers.

[0007] Benzooxazine monomers, particularly ester-containing benzooxazine monomers, and especially diester-containing benzooxazine monomers, as starting compounds for the preparation of vitrimer polymers, appear to exhibit excessively high viscosities of over 2000 mPa·s in most cases when polymerization begins (for example, at a temperature of about 140°C). Furthermore, these high viscosity values ​​are also temperature-dependent. These undesirable high viscosities significantly impair their industrial processability, for example, up to 120°C, and the molding method is complicated to perform, for example, when curing the monomer. Reactive diluents may be used to overcome these drawbacks, but this addition lowers the Tg of the final product, the solvent must be removed during the process, and it may introduce certain defects in either the final vitrimer structure or the starting monomer. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2021 / 180562 [Patent Document 2] International Publication No. 2022 / 122735 [Patent Document 3] International Publication No. 2021 / 250024 [Patent Document 4] International Publication No. 2023 / 057568 [Non-patent literature]

[0009] [Non-Patent Document 1] D. Montarnal, M. Capelot, F. Tournilhac and L. Leibler, Science, 2011, 334, pp. 965-968 [Non-Patent Document 2] A. Demongeot, R. Groote, H. Goossens, T. Hoeks, F. Tournilhac and L. Leibler, Macromolecules, 2017, 50(16), pp. 6117-6127 [Non-Patent Document 3] F. I. Altuna, V. Pettarin and R. Williams, Green Chem., 2013, 15, pp. 3360-3366 [Non-Patent Document 4] A. Legrand and C. Soulie-Ziakovic, Macromolecules, 2016, 49, pp. 5893-5902 [Non-Patent Document 5] L. Zhang, Z. Zhao, Z. Dai, L. Xu, F. Fu, T. Endo, X. Liu, ACS Macro Lett. 2019, 8, 5, pp. 506-511 [Non-Patent Document 6] Arslan M., Kiskan B., Yavuz Yagci, Sci. Rep. 2017, 7, p. 5207 [Summary of the Invention] [Means for Solving the Problems]

[0010] The present invention relates to a single ester-containing benzoxazine monomer of formula (I) that eliminates at least one of the above-described drawbacks.

[0011] [Chemical Formula] In the formula, R1’ and R1’’ are independently

[0012] [ka] And, R2' and R2'' are independent of each other.

[0013] [ka] And, R is independently selected from the group consisting of -linear or branched C1-C6 alkyl or alkoxy groups, linear or branched C2-C6 alkenyl or alkylene oxy groups, substituted or unsubstituted linear or branched C2-C6 alkynyl groups, and -C-linear or branched C1-C6 alkyl or C2-C6 alkenyl substituted or unsubstituted phenyl groups; R * H, OH and O-linear or branched C1-C6 alkyl groups, linear or branched C1-C 15 Alkyl alkyl groups, C2-C 15 Alkenyl group, C2~C 15 Alkynyl group or

[0014] [ka] Selected from the group consisting of; R'' and R ** These are independently: a linear or branched C1-C6 alkyl or alkoxy group; a linear or branched C2-C6 alkenyl or alkylene oxy group; a substituted or unsubstituted linear or branched C2-C6 alkynyl group; at least one linear or branched C1-C6 alkyl or C2-C6 alkenyl-substituted or unsubstituted o-, m-, p-phenyl group, cyclo(C3-C6 alkyl) group or heterocyclo(C3-C6 alkyl) group (where the heteroatom is selected from N, S, and O); (CH2) n 3-phenyl group (where n3 is an integer from 1 to 6), -(CH2) n1 -O-(CH2) n2 -(CH3) base (where n1 and n2 are independent integers from 1 to 10),

[0015]

Chem.

[0016]

Chem.

[0017] Preferably, R’’ and R ** are independently a straight-chain or branched C1 - C4 alkyl or alkoxy group; a straight-chain or branched C2 - C4 alkenyl or alkyleneoxy group; a substituted or unsubstituted straight-chain or branched C2 - C4 alkynyl group; at least one straight-chain or branched C1 - C6 alkyl or C2 - C6 alkenyl substituted or unsubstituted o-, m-, p-phenyl group, cyclo(C3 - C6 alkyl) group or heterocyclo(C3 - C6 alkyl) group (where the heteroatom is selected from N, S, and O), (CH2) n3 -phenyl group, especially -(CH2)[[ID=​​​​​​​​​​​​​​​​​​​​​ A selection can be made from the group consisting of the following:

[0020] Preferably, R can be selected from the group consisting of linear or branched C1-C4 alkyl or alkoxy groups, linear or branched C2-C4 alkenyl or alkyleneoxy groups, substituted or unsubstituted linear or branched C2-C4 alkynyl groups, and -C-linear or branched C1-C4 alkyl or C2-C4 alkenyl substituted or unsubstituted phenyl groups; Independently, R * H, OH, O-linear or branched C1-C4 alkyl groups, linear or branched C1-C 10 Alkyl alkyl group or C2-C 10 Alkenyl groups, more preferably linear or branched C1-C6 alkyl groups, C2-C6 alkenyl groups, or C2-C6 alkynyl groups

[0021] [ka] A selection can be made from the group consisting of the following:

[0022] The applicant has found that, surprisingly, one of the main advantages of the single ester-containing benzoxazine monomer of formula (I) is that, especially compared to diester-containing benzoxazine monomers known in the art, the monomer exhibits a constant low viscosity, for example, about 50 mPa·s to 1000 mPa·s, and more preferably about 100 mPa·s to 1000 mPa·s, preferably in a temperature range of about 80°C to 140°C, which significantly improves its processability and operability, thereby facilitating the polymerization / curing process for producing vitrimers based on the monomer. As an example, the controlled low viscosity in the aforementioned temperature range allows for molding methods under heat, such as 3D printing procedures. According to one embodiment, the viscosity can be reduced by 50% to 100% in the aforementioned temperature range.

[0023] The single ester-containing benzoxazine monomer of the present invention is advantageously suitable for obtaining polybenzoxazine derivative vitrimers by polymerization, including ring-opening and self-polymerization under heating of benzoxazine, which results in the formation of polybenzoxazine derivative vitrimers. Thanks to the specific monomer starting materials, the vitrimers of the present invention exhibit self-repairing, reshaping, reworkable, and recyclable properties. For the remainder of this document, a benzoxazine vitrimer always refers to the polymerized form of an ester-linked benzoxazine monomer.

[0024] Furthermore, the single ester-containing benzoxazine monomer of the present invention may be used in combination with or mixed with another benzoxazine monomer selected from the group consisting of, for example, a monofunctional amine crosslinked with a diphenol compound, a monophenol compound crosslinked with a diamine, a diamine crosslinked with a diphenol compound, or a mixture thereof, in order to improve the processability of the single ester-containing benzoxazine monomer during polymerization to obtain its vitrimer (improvement of the viscosity of the resulting mixture: monomer 1 of the present invention and the other monomer (monomer 2)). The properties of the polybenzoxazine derivative vitrimer are closely linked to the properties of the ester-containing benzoxazine monomer. The mixture of both monomers 1 and 2 may have a monomer 1:monomer 2 ratio of 1% to 90% by weight.

[0025] As can be seen from formula (I), the monomer includes a benzoxazine ring moiety that enables crosslinking of the monomer upon heating and facilitates the reprocessing of the resulting benzoxazine vitrimer thanks to the interchangeable ester bonds formed upon crosslinking. The benzoxazine produces thermosetting properties, such as high temperature and flammability, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage.

[0026] The presence of moieties in ester bonds and free aliphatic hydroxyl groups in benzoxazine monomers is essential for forming a dynamic and reversible network structure of benzoxazine derivative vitrimers, which allows the material to be recycled, reshaped, and reworked. Various groups in R1 and R2 (R * , R ** Since R'') is used to provide support for the OH group and the ester moiety, its inclusion, even if required, does not impair the effects of the present invention. Therefore, the essential features of the monomer of the present invention rely on the benzoxazine-containing moiety, the ester bond, and the free aliphatic hydroxyl group. The Tg of such polybenzoxazine vitrimers can be -50° to 150°C.

[0027] The present invention also relates to a method for synthesizing a single ester-containing benzoxazine monomer of formula (I), the method being: a) At least one R on the phenol ring * Phenolic carboxylic acids of formula (II) containing the group (Rac)z-COOH (II) (In the formula, Rac is a phenol ring with at least one R * A phenol containing the group R-at least one substituted or unsubstituted, wherein at least one R of the phenolic acid derivative * When R is in the ortho position relative to the -OH group, * (is H) a phenol compound containing at least one hydroxyl group of formula (III) Ral-OH (III) (In the formula, Ral is at least one R on the phenol ring) * A phenol containing the group R-at least one substituted or unsubstituted, wherein at least one R of the phenolic acid derivative * When R is in the ortho position relative to the -OH group, * A step of reacting (where H is) with a Brønsted acid-type catalyst at a temperature of 25°C to 200°C for 1 to 72 hours to produce a phenol-terminated oligomer or molecule (compound (IV)), b) Compound (IV), - Amino alcohol of formula (V):

[0028] [ka] - Primary amine of formula (VI) R ** -NH2(VI) and - Paraformaldehyde of formula (VII)

[0029] [ka] The process includes reacting a mixture of with under stirring at a temperature range of 50°C to 150°C for 1 to 10 hours to obtain a compound of formula (I), wherein in the monomer of formula (I), R, R * , R ** x', x'', y', and y'' are as defined above, where x', x'', y', and y'' represent the ratio between benzoxazine groups when prepared from an amino alcohol and another amine, i.e., a primary amine, and z is an integer from 1 to 3.

[0030] At that time, the definitions of x', x'', y', and y'' are:

[0031]

number

[0032]

number

[0033]

number

[0034]

number

[0035] The applicant has shown that a specific starting reactant yields a single ester-containing benzoxazine monomer, which then polymerizes to produce a polybenzoxazine derivative vitrimer containing benzoxazine.

[0036] When polymerization of the monomer to obtain the vitrimer is carried out, neither reactive diluents nor solvents are required, and it becomes possible to control / maintain the high Tg value of the vitrimer, from -50°C to 150°C, which is not altered by the presence of any solvent or reactive diluent. Another advantage of the obtained monomer is the aforementioned constant low viscosity of approximately 50 mPa·s to 1000 mPa·s in the temperature range of approximately 80°C to 140°C. These properties are important for the easier production of vitrimers based on the monomer.

[0037] The presence of moieties in the ester bond and free aliphatic hydroxyl groups is essential for forming a dynamic and reversible network structure of benzoxazine derivative vitrimers, which allows the material to be recycled, reshaped, and reprocessed. The amines at the hydroxyl group terminus enable cyclization and transesterification of the oxazine ring. Therefore, the essential features of the monomers of the present invention rely on the benzoxazine-containing moiety, ester bond, and free aliphatic hydroxyl group. Consequently, this method requires the use of two different amine compounds, one of which must have a hydroxyl group.

[0038] The benzoxazine rings obtained from the reaction of certain compounds ((II)-(VII)) that allow the material to be crosslinked (processed) upon heating also facilitate reprocessing thanks to interchangeable and reversible ester bonds and free aliphatic hydroxyl groups. Furthermore, the benzoxazine ring portion provides thermosetting properties such as high temperature and flammability, high strength, thermal stability, low water absorption, chemical resistance, low melt viscosity, and near-zero shrinkage.

[0039] Step b) enables the formation of R1', R1'', R2', and R2''.

[0040] Rac has R-at least one substituted or unsubstituted phenol, meaning that there may be one, two, or three substituted or unsubstituted phenol groups.

[0041] In some embodiments, a primary amine, i.e., the compound of formula (VI), may be omitted when y'+y''=0. An amino alcohol, i.e., the compound of formula (V), is used instead.

[0042] Brønsted acid catalysts are commonly used in Fischer esterifications and include p-toluenesulfonic acid (p-TSA), hydrochloric anhydride (HCl), phosphoric acid (H3PO4), methaneic acid (CH3-CO2H), sulfuric acid, tosylic acid, and Lewis acids, such as scandium(III) triflate. The catalyst content is typically 0.5% to 2% by weight.

[0043] Step a) can be advantageously carried out at a temperature in the range of 80°C to 150°C, most preferably 100°C to 140°C for the best synthesis yield higher than 95%, and the temperature selected depends on the properties of the reactants, i.e., the melting temperature of the reactant medium.

[0044] Advantageously, step a) is carried out for 12 to 24 hours for the highest yield of at least 95%, and the duration is based on the reaction rate.

[0045] In step a), the stoichiometric ratio of each of the starting reactants, phenolic carboxylic acid:at least one hydroxyl-containing phenol compound, is preferably 1.50 to 0.50 equivalents:0.50 to 1.50 equivalents, and a 1.0 equivalent oligomer or molecule of the phenol terminus (compound (IV)) is produced. In some embodiments, the stoichiometry is more preferably 1.0:1.0, or in some embodiments, 0.50:1.50 to 1.50:0.50.

[0046] The second step of the method, step b), corresponds to an optional Mannich condensation reaction in the presence of a catalyst between the phenol-terminated oligomer or molecule ((IV)) of step a) and an amino alcohol (formula (V)), a primary amine of formula (VI), and paraformaldehyde (formula (VII)). Thus, since step b) does not require the use of an external catalyst, step b) can be carried out in a simpler manner.

[0047] At that time, step b) enables the formation of R1', R1'', R2', and R2''.

[0048] Advantageously, the amino alcohol in formula (V) is R *It is a linear amino alcohol containing a group and having a primary amine moiety and an aliphatic hydroxyl moiety to obtain an oxazine ring in the highest yield and under the best reaction conditions.

[0049] The amino alcohol of formula (V) may more preferably be selected from the group consisting of 2-aminoethanol, 2-amino-2-methylpropanol, 5-aminopentan-1-ol, heptaminol, 2-(2-aminoethoxy)ethanol, and diglycolamine, or mixtures thereof.

[0050] Primary amines are R as defined above ** Includes the base.

[0051] The primary amine may be further selected from the group consisting of allylamine, methylamine, ethylamine, propylamine, butylamine, isopropylamine, hexylamine, cyclohexylamine, stearylamine, 2-aminofluorene, aminophenylacetylene, propargyl etheraniline, 4-aminobenzonitrile, furfurylamine, and aniline, or mixtures thereof.

[0052] The temperature range for step b) is preferably 80°C to 95°C, which can enable obtaining the highest conversion yield of at least 75%.

[0053] Advantageously, step b) is carried out for 1 to 8 hours, preferably 1 to 5 hours, for the highest yield of at least 75%.

[0054] In step b), the stoichiometric ratios of the starting reactants, phenol-terminated oligomers or molecules (IV):amino alcohol (V):primary amine (VI):paraformaldehyde (VII), are preferably 1.0 equivalent:z(x'+x'');z(y'+y''):2.0z, yielding 1.0 equivalent of a single ester-containing benzoxazine monomer, where x', x'', y', and y'' are independently between 0 and 1, and y'=1-x';y'' =1-x'', where both x' and x'' values ​​are not 0; x'+x''=1-(y'+y''), 0≦y'+y''<1; and z is as defined above.

[0055] Furthermore, it is assumed that the higher x' and x'' are independently, the more efficient ROP becomes.

[0056] The specific stoichiometric range depends on the equivalent proportions of the amino alcohol and primary amine. It should be noted that there is a minimum amount required for the reaction to occur. For example, the relative molar percentages of the amino alcohol to the relative molar percentages of the primary amine derivative are 10 mol% to 90 mol%, respectively. This also means that the primary amine may be omitted (0 mol%), and instead, only the amino alcohol may be used (100 mol%). Furthermore, the selected stoichiometric range for both the amino alcohol / amine and paraformaldehyde is preferable to avoid the formation of linear and / or aliphatic byproducts of the reaction, such as oxazolidines, triaza derivatives, or condensed derivatives.

[0057] The synthesis of single ester benzoxazine monomers can, most preferably, be solvent-free, even if a solvent may be added to dissolve the starting reactants. The method involves a one-step synthesis, which is one of the advantages of the present invention.

[0058] Advantageously, the total synthesis may generally not require further monomer purification for the present invention to be carried out. However, if necessary, monomer purification may be performed by some known technique (vacuum, distillation, etc.).

[0059] The reaction mixtures in both steps a) and b) are stirred using a classical mechanical stirrer or any non-limiting means.

[0060] The method can be carried out on a laboratory or industrial scale using a suitable container and by any known means familiar to those skilled in the art.

[0061] The present invention also relates to a method for preparing a polybenzoxazine derivative vitrimer, comprising a polymerization step of 1 to 24 hours at a temperature in the range of 100°C to 250°C for a single ester-containing benzoxazine monomer (formula (I)) that can be obtained by the present invention or the method described above, for obtaining a polybenzoxazine derivative vitrimer.

[0062] In the present invention, "derivative" means that the resulting vitrimer is obtained by polymerization of the benzoxazine monomer of the present invention and is derived therefrom. Therefore, "polybenzoxazine derivative vitrimer" and "polybenzoxazine vitrimer" have the same meaning.

[0063] As mentioned above, since a viscosity of approximately 50 mPa·s to 1000 mPa·s is maintained constant within a specific temperature range of approximately 80°C to 140°C, no reactive diluent or solvent is required when polymerization of the monomer is carried out to obtain a vitrimer. Due to the reduced viscosity, the aforementioned manufacturing method (obtaining the vitrimer) can be controlled more easily and carried out faster compared to known vitrimer manufacturing methods.

[0064] According to the method for preparing the vitrimer of the present invention, the polymerization step, which is a curing step, allows the benzoxazine ring to open and react with itself to form a 3D network structure. Once cooled, the shape of the material is maintained for several months, typically 2 to 4 months. Reheating to at least 100°C for several minutes allows the ester bonds to be exchanged with aliphatic hydroxyl groups, enabling the material to be reshaped, recycled, or reworked; while maintaining structural integrity and the number of covalent bonds. Considering that the Mannich condensation reaction is quantitative, approximately two hydroxyl groups can react with each ester bond by transesterification (even after curing). The vitrimer behavior is also considered to be the vitrimer freeze topology transition temperature (T), which is the temperature at which the transesterification reaction significantly increases. v It strongly depends on ). The vitrimer behavior has been verified by several experiments. After the curing process, the vitrimer is T vBy heating to higher temperatures, the initial shape of the vitrimer can be designed to change to another original shape. For example, the vitrimer may be ground into a powder and reshaped or reprocessed at 150°C for several minutes. However, its shape remains stable at room temperature.

[0065] The polymerization duration depends on the curing temperature and / or the properties of the single-ester-containing benzoxazine monomer. The polymerization temperature is selected to be higher than the temperature required to synthesize a given monomer. Generally, the higher the polymerization temperature, the shorter the curing duration. For example, at a polymerization temperature of 250°C, the curing duration may be at least 1 hour, while at a polymerization temperature of 100°C, the curing duration may be 24 hours or less. Preferably, the curing temperature may be 140°C to 200°C, more preferably 140°C to 180°C, with the latter range resulting in a curing duration of 1.5 to 3 hours, preferably 1.5 to 2.5 hours. Polymerization can be carried out by any known heating means, such as laser beams and infrared beams.

[0066] The method may also include a post-polymerization step, which may preferably be a heating step carried out at a higher temperature than the polymerization heating step.

[0067] The present invention also relates to polybenzoxazine derivative vitrimers obtained by the above method and capable of exhibiting at least one of the following features: (i) 100°C to 250°C; preferably 130°C to 220°C, more preferably 130°C to 190°C v (Topological freeze transition temperature) value, and (ii) 100°C to 300°C, preferably 130°C to 200°C, more preferably 130°C to 180°C, ≥ T v The relaxation temperature value is a numerical value.

[0068] Vitrimmer T v The value generally depends on the properties and content of the catalyst in step b), if present.

[0069] The relaxation temperature typically corresponds to the relaxation temperature of the vitrimer after applying physical deformation such as strain, e.g., torsion, and without any signs of vitrimer degradation.

[0070] To the advantage, Vitrimer also, A relaxation time of -0.5 seconds to 2 hours, preferably 1 second to 1 hour, more preferably 5 seconds to 50 minutes. Conventionally, the relaxation time is defined as the time it takes for a sample to relax to a value corresponding to 1 / e(0.37) of its original modulus of elasticity. Generally, the higher the temperature, the shorter the relaxation time. For example, the relaxation time is about 150 min to 200 s at a temperature of 120°C to 170°C, and ≤200, preferably 100 s to 20 s, in the temperature range of 150°C to 200°C. In some embodiments, the vitrimer can be deformed by 0.1% to 100% of its initial size; - The activation energy related to the relaxation time may be 50 kJ / mol to 200 kJ / mol, preferably 70 kJ / mol to 170 kJ / mol, more preferably 100 kJ / mol to 160 kJ / mol; and - The processing temperature may be 100°C to 250°C, preferably 130°C to 250°C, more preferably 150°C to 200°C, and most preferably 150°C to 170°C. It may also show at least one feature selected from the group consisting of the following.

[0071] The vitrimer according to the present invention may also, very preferably, behave as a thermosetting resin and / or exhibit insolubility in many solvents such as water, CHCl3, CH2Cl2, DMF, THF, toluene and / or xylene, ketones, alcohols or carboxylic acids, without limitation. Swelling properties are observed to the extent of 0-500% of its initial weight. Swelling experiments may be performed in various solvents, such as acetone, chloroform and water, to evaluate the formation of a crosslinked reticular structure. Of these, chloroform is the solvent in which the vitrimer exhibits the highest swelling ratio of about 100%. In acetone and water, the vitrimer swells by 40-50% and 20-30%, respectively.

[0072] The vitrimer of the present invention exhibits self-healing, reshaping, reworkable, recyclable, and reversible adhesive properties.

[0073] The vitrimer can constitute an intermediate layer between at least two substrates, such as metals, polymers, glass, and ceramic materials. The resulting composite material can be prepared by setting at least one ester-containing benzoxazine monomer between the two considered substrates and then curing it at a temperature that yields a vitrimer without altering the integrity of the substrates. Each substrate may be different from the others.

[0074] The metal substrate is not limited and may be aluminum, iron, steel, etc.

[0075] The polymer substrate may be polycarbonate, acrylic, polyamide, polyethylene, or terephthalate.

[0076] Benzoxazine vitrimers can then be advantageously used in a wide range of fields of science and technology, such as electronics, aerospace, defense, and automotive.

[0077] The present invention also, a) Benzoxazine derivatives containing a single ester of formula (I), and b) Additional compounds of at least one organic molecular type, with or without a benzoxazine moiety. This also relates to composition A, which contains [the specified element].

[0078] Preferably, the organic molecular type may be a polymer containing or not containing a benzoxazine moiety.

[0079] Additional compounds may be used to enhance the properties of the monomer, vitrimer, or both (i.e., viscosity, mechanical, and thermal properties).

[0080] The polymer may be an epoxy resin, bismaleimide resin, phenolic resin or benzoxazine resin, polyurethane, polyamide, polyolefin, polyester, or rubber. The ester-containing benzoxazine derivative of formula I may be used in a weight ratio of 0.1 to 80% of the final composition.

[0081] The compound of formula (I) can be used to impart vitrimer properties (self-healing, reworkability, etc.) to the polymers described above.

[0082] The present invention also, a) A single ester-containing benzoxazine monomer of formula (I), and b) Materials selected from the group consisting of fillers, fibers, pigments, dyes, and plasticizers The same applies to composition B, which contains [the specified substance].

[0083] Additional compounds may be used to enhance the properties of monomers, vitrimers, or both (i.e., viscosity, mechanical, and thermal properties).

[0084] The additional compounds could be carbon fibers, glass fibers, clay, carbon black, silica, carbon nanotubes, graphene, or any means known for thermal or mechanical reinforcement of composites.

[0085] The present invention also relates to the use of the vitrimer according to the present invention as a reversible adhesive, sealant, coating, or encapsulation system for substrates selected from the group consisting of metals, polymers, glass, and ceramic materials. Preferably, the metals and polymers are as defined above.

[0086] The present invention also relates to the use of the Vitrimer according to the present invention in a 3D printing method or additive manufacturing method.

[0087] The following examples, along with the attached figures, provide further details of several embodiments. [Brief explanation of the drawing]

[0088] [Figure 1] Figure 1 shows the synthesis reaction of a monoester and a monofunctional phenolic acid to produce 2-(3-(2-hydroxyethyl)-3,4-dihydro-2H-benzo[e][1,3]oxazine-6-yl)ethyl 3-(2-(2-hydroxyethyl)-3,4-dihydro-2H-benzo[e][1,2]oxazine-6-yl)propanoate (TYR-PA-mea). [Figure 2] Figure 2 shows the NMR spectrum of TYR-PA-mea ester-containing benzoxazine monomers. [Figure 3] Figures 3a and 3b show the DSC and isothermal rheology monitoring (140°C) curves of TYR-PA-mea and TYR-PA-fu ester-containing benzoxazine monomers, respectively, where "fu" represents furfurylamine. [Figure 4] Figures 4(a) and (b) show isothermal rheological monitoring of the viscosity shear rate of TYR-PA-mea / fu ester-containing benzoxazine monomers at various temperatures. [Figure 5] Figure 5 shows the synthesis reaction of the monoester TYR-PA-dga. [Figure 6] Figure 6 shows the NMR spectrum of the TYR-PA-dga ester-containing benzoxazine monomer. [Figure 7] Figure 7 shows the synthesis reaction of the monoester TYR-DPA-dga1.75 / ste0.25. [Figure 8] Figure 8 shows the NMR spectrum of a benzoxazine monomer containing TYR-DPA-dga1.75 / ste0.25 ester. [Figure 9] Figure 9 shows the viscosity evolution of TYR-PA-mea from Example 1 and the conventional diester-containing monomer PEG-DPA-mea at 50°C and 80°C. [Modes for carrying out the invention]

[0089] Example 1: Synthesis of benzoxazine (TYR-PA-mea) containing free aliphatic hydroxyl groups and monoesters using tyrosol, phloretic acid, monoethanolamine, and paraformaldehyde. A TYR-PA-mea monoester benzoxazine containing free aliphatic hydroxyl groups was synthesized in two steps (Figure 1). The first step, step a), corresponds to the Fischer esterification of 2-(4-hydroxyphenyl)ethanol (tyrosol, TYR) (1 equivalent) and 3-(4-hydroxyphenyl)propionic acid (floretic acid, PA) (1 equivalent) in the presence of a catalytic amount (0.5 wt%) of p-toluenesulfonic acid. The reactants were melted together at 130°C and stirred by mechanical stirring for 24 hours to obtain 4-hydroxyphenethyl 3-(4-hydroxyphenyl)propanoate (TYR-PA) (1 equivalent).

[0090] The second step, step b), corresponds to the Mannich condensation of TYR-PA (1 equivalent) with monoethanolamine (mea) (2 equivalents) and paraformaldehyde (PFA) (4 equivalents). All of these reactants are stirred together by mechanical stirring and reacted in a molten state at 70°C for 8 hours to obtain TYR-PA-mea monoester benzoxazine containing free aliphatic hydroxyl groups, and 2-(3-(2-hydroxyethyl)-3,4-dihydro-2H-benzo[e][1,3]oxazin-6-yl)ethyl 3-(2-(2-hydroxyethyl)-3,4-dihydro-2H-benzo[e][1,2]oxazin-6-yl)propanoate.

[0091] In this compound, x'=1, x''=1, and y'=y''=0.

[0092] Figure 2 shows the TYR-PA-mea ester-containing benzoxazine monomer. 1 The 1H NMR spectrum (AVANCE III HD Bruker spectrometer) is shown.

[0093] In Example 1, no primary amine is used at all (y'+y''=0), and monoethanolamine is used (which plays the role of the primary amine).

[0094] Example 2 A compound named TYR-PA-fu ester-containing benzoxazine monomer is obtained in the same manner as in Example 1, except that furfurylamine is used instead of monoethanolamine. This compound is not in accordance with the present invention and is used as a comparative example.

[0095] TYR-PA-fu:2-(3-(furan-2-ylmethyl)-3,4-dihydro-2H-benzo[e][1,3]oxazin-6-yl)ethyl 3-(2-(furan-2-ylmethyl)-3,4-dihydro-2H-benzo[e][1,2]oxazin-6-yl)propanoate.

[0096] Therefore, Figure 3a shows the DSC thermogram of a benzoxazine containing a polyfunctional monoester. The abbreviations "mea" and "fu" correspond to monoethanolamine (with a free hydroxyl group at the end) and furfurylamine (with a furan group at the end), respectively. The DSC thermogram of the TYR-PA-fu furfurylamine-containing benzoxazine monomer shows a first exothermic peak starting at a temperature of 150°C. This peak is associated with the ring-opening of the benzoxazine ring upon heating. Ring-opening of the benzoxazine ring occurred at a much lower temperature in the case of the TYR-PA-mea benzoxazine monomer containing a free alcohol group in the present invention. The first exothermic peak starts at 100°C and is located at a maximum of approximately 170°C. The transesterification reaction between the ester bond and the aliphatic hydroxyl group promotes the thermal ring-opening polymerization of the benzoxazine monomer. The second exothermic peak corresponds to the degradation of the aliphatic ester and was observed in both cases (mea and fu).

[0097] The curing of TYR-PA-mea / fu ester-containing benzoxazine monomers was monitored by rheological measurements in Figure 3b. Rheograms were performed under the following conditions: 1 Hz, linear amplitude of 1-0.1%; on a 25 mm plate. The test was carried out according to a heating lamp at 15°C / min from 80°C to 140°C, followed by isothermal measurements at 140°C. Complex viscosity was recorded as a function of time. The term "gelation time" is defined as the time it takes for the complex viscosity of the softened monomer to suddenly increase and convert to a gel. At 160°C, the gelation times were reached after 410 and 2200 s for TYR-PA-mea and TYR-PA-fu, respectively.

[0098] Figures 4(a) and (b) show isothermal rheological monitoring of the viscosity shear rate of TYR-PA ester-containing benzoxazine monomers, where "fu" represents furfurylamine.

[0099] The rheogram is calculated under the following conditions: shear rate logarithmic slope 100~0.01s -1 The process is performed on a 50 mm plate. The viscosity of the TYR-PA-mea / fu ester-containing benzoxazine monomer was monitored by rheological measurements in Figures 4(a) and (b). The viscosity of the TYR-PA-mea / fu ester-containing benzoxazine monomer is lower than 1000 mPa·s at 75 and 100°C. Compound TYR-PA-fu is not a vitrimer because it lacks free OH groups (x'=x''=0). Compound TYR-PA-fu (not according to the present invention) has a smaller processing window and a longer curing duration than that according to the present invention.

[0100] Example 3: Synthesis of a benzoxazine containing a free aliphatic hydroxyl group and one ester group, according to the present invention, from 2-(4-hydroxyphenyl)ethanol (TYR), 3-(4-hydroxyphenyl)propionic acid (PA) as a phenolic acid derivative, and diethylene glycol (dga) as a primary amine having an aliphatic OH group. The TYR-PA-dga benzoxazine monomer containing a free aliphatic hydroxyl group was synthesized in two steps (Figure 5). The first step, step a), corresponds to the Fischer esterification of 3-(4-hydroxyphenyl)propionic acid (floretic acid, PA) (1 equivalent) and 2-(4-hydroxyphenyl)ethanol (tyrosol, TYR) (1 equivalent) in the presence of a catalytic amount (0.5 wt%) of p-toluenesulfonic acid. The reactants were melted together at 130°C and stirred by mechanical stirring for 24 hours to obtain (TYR-PA) (1 equivalent).

[0101] The second step, step b), corresponds to the Mannich condensation of TYR-PA (1 equivalent) with diethylene glycolamine (dga) (2 equivalents) and paraformaldehyde (PFA) (4 equivalents). All of these reactants were stirred together by mechanical stirring and reacted in a molten state at 70°C for 8 hours (85°C for 2 hours) to obtain TYR-PA-dga benzoxazine containing free aliphatic hydroxyl groups.

[0102] In the above embodiment, the primary amine is removed, and diethylene glycolamine (DGA) is used to yield both parts (primary amine and amino alcohol).

[0103] In this compound, x'=1, x''=1, and y'=y''=0.

[0104] Figure 6 shows the TYR-PA-dga ester-containing benzoxazine monomer. 1 The 1H NMR spectrum (AVANCE III HD Bruker spectrometer) is shown.

[0105] In this example 3, a primary amine is not used (y'+y''=0), and diethylene glycolamine is used (which plays the role of a primary amine).

[0106] Example 4. Synthesis of a benzoxazine containing a free aliphatic hydroxyl group and one ester group from 2-(4-hydroxyphenyl)ethanol (TYR), 4,4-bis(4-hydroxyphenyl)pentanoic acid (DPA) as a phenolic acid derivative, diethylene glycol (dga) as a primary amine having an aliphatic OH group, and stearylamine (ste) as a primary amine. The TYR-DPA-dga1.75 / ste0.25 benzoxazine monomer containing free aliphatic hydroxyl groups was synthesized in two steps (Figure 7). The first step, step a), corresponds to the Fischer esterification of 4,4-bis(4-hydroxyphenyl)pentanoic acid (diphenolic acid, DPA) (1 equivalent) and 2-(4-hydroxyphenyl)ethanol (tyrosol, TYR) (1 equivalent) in the presence of a catalytic amount (0.5 wt%) of p-toluenesulfonic acid. The reactants were melted together at 130°C and stirred by mechanical stirring for 24 hours to obtain (TYR-DPA) (1 equivalent).

[0107] The second step, step b), corresponds to the Mannich condensation of TYR-DPA (1 equivalent) with diethylene glycolamine (dga) (1.75 equivalents), stearylamine (ste) (0.25 equivalents), and paraformaldehyde (PFA) (4 equivalents). All of these reactants were stirred together by mechanical stirring and reacted in a molten state at 70°C for 8 hours to obtain TYR-DPA-dga1.75 / ste0.25 benzoxazine containing free aliphatic hydroxyl groups.

[0108] In the above embodiment, the primary amine is removed, and diethylene glycolamine (DGA) is used to yield both parts (primary amine and amino alcohol).

[0109] In this compound, x'=1, x''=0.75, y'=0, and y''=0.25.

[0110] Figure 8 shows the TYR-PA-mea ester-containing benzoxazine monomer. 1The 1H NMR spectrum (AVANCE III HD Bruker spectrometer) is shown.

[0111] In the above example, a primary amine is not used (y'+y''=0), and diethylene glycolamine is used (which plays the role of a primary amine).

[0112] Example 5: Comparative Example This Example 5 compares the viscosity versus time course of the TYR-PA-mea monoester benzoxazine containing free aliphatic hydroxyl groups from Example 1 and the diester-containing monomer PEG-DPA-mea described in International Publication of the Prior Art 2021 / 250024 (Example 1).

[0113] The results are shown in Figure 9. The viscosity level is considerably lower with the TYR-PA-mea monoester benzoxazine of the present invention compared with the conventional diester-containing monomer PEG-DPA-mea.

[0114] conclusion Single-ester-containing benzoxazine monomers, compared particularly with diester-containing benzoxazine monomers known in the art, exhibit a lower constant viscosity, for example, in the temperature range of about 80°C to 140°C, due to the single-ester portion, as can be inferred, for example, from Example 2.

[0115] The presence of moieties in the ester bond and free aliphatic hydroxyl groups in single-ester-containing benzoxazine monomers is essential for forming a dynamic and reversible network structure of benzoxazine derivative vitrimers, which allows the material to be recycled, reshaped, and reprocessed.

Claims

1. A single ester-containing benzoxazine monomer of formula (I). 【Chemistry 1】 [In the formula, R １ 'and R １ '' is independent, 【Chemistry 2】 And, R ２ 'and R ２ '' is independent, 【Transformation 3】 And, R is independently, a straight-chain or branched C １ ~C ６ alkyl or alkoxy group, straight-chain or branched C ２ ~C ６ alkenyl or alkyleneoxy group, substituted or unsubstituted straight-chain or branched C ２ ~C ６ alkynyl group, and -C-straight-chain or branched C １ ~C ６ alkyl or C ２ ~C ６ is selected from the group consisting of alkenyl-substituted or unsubstituted phenyl groups; R ＊ These are H, OH and O-linear or branched C １ ~C ６ Alkyl, linear, or branched C １ ~C １５ alkyl group, C ２ ~C １５ Alkenyl group, C ２ ~C １５ Alkynyl group or 【Chemistry 4】 Selected from the group consisting of; R'' and R ＊＊ These are independently linear or branched C １ ~C ６ Alkyl or alkoxy group; linear or branched C ２ ~C ６ Alkenyl or alkylene oxy group; substituted or unsubstituted linear or branched carbon atoms. ２ ~C ６ Alkynyl group; at least one linear or branched carbon chain １ ~C ６ Alkyl or C ２ ~C ６ Alkenyl-substituted or unsubstituted o-, m-, p-phenyl groups, cyclo(C) ３ ~C ６ Alkyl group or heterocyclo(C) ３ ~C ６ (alkyl) group (where the heteroatom is selected from N, S, and O); (CH ２ ) ｎ３ - Phenyl group (where n3 is an integer from 1 to 6), - (CH ２ ) ｎ１ -O-(CH ２ ) ｎ２ - (CH ３ ) base (where n1 and n2 are independently integers from 1 to 10), 【Transformation 5】 , and 【Transformation 6】 Selected from the group consisting of; x', x'', y', and y'' are independent of each other, ranging from 0 to 1, and y' = 1 - x'; y'' ＝ 1 - x'', and both the x' and x'' values ​​are not 0; x' + x'' = 2 - (y' + y''), 0 ≤ y' + y'' < 2; However, when x'' ≥ 0, x' > 0, and when x'' > 0, x' ≥ 0.

2. R'' and R ＊＊ However, independently, linear or branched C １ ~C ４ Alkyl or alkoxy group, linear or branched C ２ ~C ４ Alkenyl or alkylene oxy group, substituted or unsubstituted linear or branched carbon. ２ ~C ４ Alkynyl group, at least one linear or branched C １ ~C ６ Alkyl or C ２ ~C ６ Alkenyl-substituted or unsubstituted o-, m-, p-phenyl groups, cyclo(C) ３ ~C ６ Alkyl group or heterocyclo(C) ３ ~C ６ Alkyl group (where the heteroatom is selected from N, S, and O), (CH ２ ) ｎ３ - Phenyl group, especially - (CH ２ ) ｎ３－ Substituted or unsubstituted furan, phenyl (where n3 is an integer from 1 to 4), -(CH ２ ) ｎ１ -O-(CH ２ ) ｎ２ - (CH ３ ) base (where n1 and n2 are independent integers from 1 to 6), 【Transformation 7】 , and 【Transformation 8】 A single ester-containing benzoxazine monomer according to claim 1, selected from the group consisting of the following.

3. R is a linear or branched C １ ~C ４ Alkyl or alkoxy group, linear or branched C ２ ~C ４ Alkenyl or alkylene oxy group, substituted or unsubstituted linear or branched carbon. ２ ~C ４ Alkynyl group, and -C- linear or branched C １ ~C ４ Alkyl or C ２ ~C ６ Selected from the group consisting of alkenyl-substituted or unsubstituted phenyl groups; Independently, R ＊ is H, OH, O-linear or branched C １ ~C ４ alkyl group, linear or branched C １ ~C １０ alkyl group or C ２ ~C １０ alkenyl group, more preferably linear or branched C １ ~C ６ alkyl group, C ２ ~C ６ alkenyl group or C ２ ~C ６ alkynyl group or 【Transformation 7】 A single ester-containing benzoxazine monomer according to claim 1 or 2, selected from the group consisting of the following.

4. The single ester-containing benzoxazine monomer according to any one of claims 1 to 3, wherein the monomer exhibits a constant viscosity of 50 mPa·s to 1000 mPa·s in a temperature range of about 80°C to 140°C.

5. A method for synthesizing a single ester-containing benzoxazine monomer of formula (I), a) Phenolic carboxylic acid of formula (II) (Rac)z-COOH (II) (In the formula, Rac is at least one R on the phenol ring) ＊ A phenol containing the group R-at least one substituted or unsubstituted phenol, provided that at least one R of the phenolic acid derivative ＊ When R is in the ortho position relative to the -OH group, ＊ (is H) a phenol compound containing at least one hydroxyl group of formula (III) Ral-OH (III) (wherein, Ral is R - at least one substituted or unsubstituted phenol containing at least one R group on the phenol ring, provided that when at least one R of the phenol acid derivative is in the ortho position with respect to the - OH group, R is H) ＊ group, and is R - at least one substituted or unsubstituted phenol, provided that when at least one R of the phenol acid derivative is in the ortho position with respect to the - OH group, ＊ R is in the ortho position relative to the - OH group, ＊ R is H) The process involves reacting the material at a temperature of 25°C to 200°C for 1 to 72 hours in the presence of a Brønsted acid-type catalyst to produce a phenol-terminated oligomer or molecule (compound (IV)). b) Compound (IV), - Amino alcohol of formula (V): 【Transformation 8】 - Primary amine of formula (VI) R ＊＊ -NH ２ (VI) and - Paraformaldehyde of formula (VII) 【Chemistry 9】 The process involves reacting a mixture of these ingredients with stirring at a temperature range of 50°C to 150°C for 1 to 10 hours to obtain the compound of formula (I). It includes, and in the monomer of formula (I), R, R ＊ , R ＊＊ x', x'', y', and y'' are as defined in any one of claims 1 to 3, In this method, x', x'', y', and y'' represent the ratios between benzoxazine groups when prepared from amino alcohols and other amines, and z is an integer between 1 and 3.

6. The method according to claim 5, wherein step a) can be advantageously carried out at a temperature in the range of 80°C to 150°C, most preferably 100°C to 140°C.

7. The method according to claim 5 or 6, wherein the stoichiometric ratio of the starting reactants in step a) is 1.50 to 0.50 equivalents: 0.50 to 1.50 equivalents of the phenol compound containing at least one hydroxyl group, and a phenol-terminated oligomer or molecule (compound (IV)) of 1.0 equivalent is produced.

8. The amino alcohol in formula (V) is R ＊ The method according to any one of claims 5 to 7, wherein the linear amino alcohol contains a group and has a primary amine moiety and an aliphatic hydroxyl moiety.

9. The method according to any one of claims 5 to 8, wherein the primary amine is selected from the group consisting of allylamine, methylamine, ethylamine, propylamine, butylamine, isopropylamine, hexylamine, cyclohexylamine, stearylamine, 2-aminofluorene, aminophenylacetylene, propargyl etheraniline, 4-aminobenzonitrile, furfurylamine, and aniline, or a mixture thereof.

10. In step b), the stoichiometric ratios of the starting reactants, phenol-terminated oligomers or molecules (IV): amino alcohol (V): primary amine (VI): paraformaldehyde (VII), are 1.0 equivalent: z(x'+x'') equivalent: z(y'+y'') equivalent: 2.0 z equivalent, producing 1.0 equivalent of a single ester-containing benzoxazine monomer, where x', x'', y', and y'' are independently between 0 and 1, and y' = 1 - x'; y'' ＝ The method according to any one of claims 5 to 9, wherein z is 1 - x'', and both the x' and x'' values ​​are not 0; x' + x'' = 1 - (y' + y''), and 0 ≤ y' + y'' < 1; and z is 1, 2, or 3.

11. A method for preparing a polybenzoxazine derivative vitrimer, comprising the step of polymerizing a single ester-containing benzoxazine monomer of formula (I), which can be obtained by any one of claims 1 to 4 or any one of claims 5 to 10, at a temperature in the range of 100°C to 250°C for 1 to 24 hours.

12. The following features: (i) T 100°C to 250°C; preferably 130°C to 220°C, more preferably 130°C to 190°C ｖ Value, and (ii) 100°C to 300°C, preferably 130°C to 200°C, more preferably 130°C to 180°C, ≥ T ｖ The relaxation temperature value is a value. A polybenzoxazine derivative vitrimer exhibiting at least one of the following.

13. Relaxation period of 0.5 seconds to 2 hours, preferably 1 second to 1 hour, more preferably 5 seconds to 50 minutes; Activation energies related to relaxation time, ranging from 50 kJ / mol to 200 kJ / mol, preferably 70 kJ / mol to 170 kJ / mol, more preferably 100 kJ / mol to 160 kJ / mol; and Processing temperature of 100°C to 250°C, preferably 130°C to 250°C, more preferably 150°C to 200°C, and most preferably 150°C to 170°C. The polybenzoxazine derivative vitrimer according to claim 12, which shows the above.

Images