Benzoxazine mixture based on cannabinoids, polymers thereof, and process for preparing a corresponding benzoxazine mixture

Abstract

The present invention relates to: a benzoxazine mixture which is prepared or can be prepared from a mixture of cannabinoids; a polymer or oligomer which is prepared or can be prepared from a benzoxazine mixture according to the invention; a fiber composite material comprising fibers and a polymer according to the invention; the use of an extract of hemp plants for preparing a benzoxazine mixture according to the invention; the use of the benzoxazine mixture according to the invention for preparing a polymer; a process for preparing a benzoxazine mixture according to the invention; and a process for preparing a polymer or a fiber composite material.

Description

[0001] Fraunhofer Society for the Promotion of

[0002] applied research registered association

[0003] Hansastrasse 27c, 80686 Munich

[0004] Benzoxazine mixture based on cannabinoids, polymers thereof, and methods for producing a corresponding benzoxazine mixture

[0005] The present invention relates to a benzoxazine mixture produced from, or produced from, a mixture of cannabinoids, a polymer or oligomer produced from or producible from a benzoxazine mixture according to the invention, a fiber composite material comprising fibers and a polymer according to the invention, the use of an extract from hemp plants (Cannabis sativa L., subspecies indica Lam., subspecies ruderalis Janisch., and hybrids) for the production of a benzoxazine mixture according to the invention, the use of the benzoxazine mixture according to the invention for the production of a polymer, a method for producing a benzoxazine mixture according to the invention, and a method for producing a polymer or a fiber composite material.

[0006] There is a constant need for materials that can be produced using renewable raw materials.

[0007] Polymers based on benzoxazine monomers are generally known. However, there is a need to develop renewable sources of these monomers while simultaneously providing the basis for polymers with suitable property windows. Ensuring the availability of these renewable sources and the appropriate processability of currently developed bio-based benzoxazines still pose significant challenges and hinder their scaled-up industrial application.

[0008] Against this background, the object of the present invention was to specify the basic materials for polymers, wherein the basic materials are readily available, preferably obtainable from plant sources, and form the basis for polymers with a favorable property window. It is preferred that the resulting polymers have a favorable glass transition temperature, that the monomers and / or the polymers derived therefrom possess good thermal stability, particularly in the polymerization temperature range, and / or that polymers with the lowest possible porosity are formed during polymerization. It is particularly preferred that a favorable property window can be achieved from several or preferably all of these properties.

[0009] This problem is solved according to the invention by a benzoxazine mixture, produced or producible from a mixture of cannabinoids.

[0010] A benzoxazine mixture within the meaning of this text exists if at least two benzoxazines are contained in the mixture, wherein the main component may constitute a maximum of 99.55 wt.%, preferably a maximum of 99.5 wt.%, based on the total weight of all benzoxazines contained in the mixture.

[0011] Such a benzoxazine mixture can be readily obtained by converting cannabinoids from the hemp plant, thus providing a natural source for a starting material of the benzoxazine mixture according to the invention, and these starting materials are also easily accessible.

[0012] Accordingly, it is preferred that for the benzoxazine mixture according to the invention at least some of the cannabinoids are a cannabinoid or several cannabinoids in the form of carboxylic acid or carboxylic acids from the biosynthesis of the hemp plant.

[0013] Cannabinoids, as described here, are a group of biogenic or (semi-)synthetic chemical compounds that have the chemical structure of terpenophenols or terpenoids benzopyran. They can exist as carboxylic acids as well as in decarboxylated form (neutral form).

[0014] The hemp plant, particularly in its flowering stage, contains up to 125 different cannabinoids as biophenols, some of which can constitute more than 40% of its dry mass. These cannabinoids can be extracted using simple and cost-effective methods and are already available on the market in pure form and larger quantities, although some are still subject to narcotics legislation. With the current changes in the political and legal landscape, even greater availability is expected in the future. The cannabinoids can be used, for example, with cannabidiol (CBD) as a phenolic component for the synthesis of benzoxazine monomers. Due to the large number of cannabinoids and the resulting high structural variability, benzoxazines could, if possible, be designed using a modular approach to meet various requirements.The innovation lies not only in the synthesis and use of polybenzoxazines from cannabinoids as structural materials, but also in the simplification of the production process and the local availability of biophenols in Europe for this purpose. The variability of the resin mixture for adjusting the properties could be advantageous, as could the complete utilization of all biogenic components, offering both economic and ecological benefits.

[0015] Most cannabinoids contain double bonds in addition to phenolic groups. These double bonds in the molecule allow for:

[0016] New cross-connections are created, leading to improved material properties.

[0017] or they are used for UV curing (partial cross-linking to dimensionally stable, but still reactive polymers).

[0018] or they are used for epoxidation (the phenol component contains a benzoxazine and an epoxide ring).

[0019] A benzoxazine mixture according to the invention is preferred, wherein at least some of the cannabinoids are a cannabinoid or several cannabinoids from the biosynthesis of the hemp plant in neutral, decarboxylated form.

[0020] In neutral, decarboxylated form, cannabinoids can be used in a particularly advantageous way for the synthesis of benzoxazines.

[0021] Accordingly, it may be preferred that the benzoxazine mixture according to the invention is produced or can be produced from full-spectrum oil from the hemp plant by reactions of at least two of the cannabinoids contained therein with one or more amines.

[0022] In the context of this text, "full-spectrum oil" refers to an extract from the hemp plant consisting of the entire spectrum of secondary plant compounds, i.e., biogenic chemical compounds, contained in the plant parts. These are primarily cannabinoids, but also terpenes, terpenoids, and flavonoids (Vigil et al., 2020, https: / / doi.org / 10.3390 / life10050069). Extraction is preferably carried out using hot presses, ethanol, or microwave extraction.

[0023] A benzoxazine mixture according to the invention is also preferred, wherein the mixture of benzoxazines comprises or consists of at least 3, more preferably at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 15, at least 20, at least 40, at least 60, at least 80 and particularly preferably at least 100 cannabinoids.

[0024] These benzoxazine mixtures are particularly easy to access, as they can be obtained, for example, from full-spectrum oil from the hemp plant.

[0025] According to the invention, it may be preferable to extract only certain parts of the hemp plant, in particular the above-ground plant material, especially from the female hemp plant, and most preferably the flowers as a basis for cannabinoid extraction.

[0026] The flowers of the female hemp plant, with their characteristic trichomes (resin glands), contain the highest concentrations of cannabinoids and terpenes (approximately 30–60% of dry weight). The unfertilized inflorescences with trichomes are preferable for extracting the resinous cannabinoid-terpene mixture. However, the other parts of the hemp plant (Cannabis sativa L., subspecies indica Lam., subspecies ruderalis Janisch., and hybrids) in both male and female plants also contain smaller amounts of cannabinoids, with decreasing concentrations as follows: sugar leaves near the inflorescences and other leaves (approximately 0.05% of dry weight), the epidermis of the stem and the stem itself (approximately 0.02% of dry weight), and only traces of cannabinoids in the roots. The seeds contain no cannabinoids or terpenes. (Glivar et al., 2020, https: / / doi.Org / 10.1016 / i.indcrop.2019.112082)

[0027] A benzoxazine mixture according to the invention is preferred, wherein at least 20 wt.%, preferably at least 30 wt.%, further preferably at least 40 wt.%.-% from one of the cannabinoids and their homologs selected from the group consisting of cannabinoids and their homologs selected from the group consisting of CBDA (cannabidiolic acid), CBDVA (cannabidivarinic acid), CBNA (cannabinolic acid), CBGA (cannabigerolic acid), CBCA (cannabichromenic acid), CBLA (cannabicyclolic acid), THC (tetrahydrocannabinol), Δ9-THC (delta-9-tetrahydrocannabinol), Δ8-THC (delta-8-tetrahydrocannabinol), CBD (cannabidiol), CBG (cannabigerol), CBN (cannabinol), CBC (cannabichromene), THCV (tetrahydrocannabivarin), CBDV (cannabidivarin), CBL (cannabicyclol), CBE (cannabielsoin), CBT (cannabitriol), Isocannabinoids, CBCN (cannabichromene varen), THCA (tetrahydrocannabinolic acid) C4 isomer and THCA C3 isomer, wherein the aforementioned weight fraction is more preferably derived from only two, or more preferably from only one of the aforementioned cannabinoids.

[0028] The stated percentages by weight refer to the total amount of benzoxazines contained in the benzoxazine mixture.

[0029] A benzoxazine mixture according to the invention is preferred, wherein the cannabinoids have been reacted with at least one amine selected from the group consisting of aromatic and non-aromatic amines, which may each be mono-, di- or multifunctional, as well as mixtures of the corresponding amines, preferably selected from the group consisting of aniline, diaminodiphenylmethane, hexamethylenediamine, polyetheramines, furfurylamine, 2,5-furandimethanamine, wherein it is preferred that the cannabinoids have been reacted with only one amine compound.

[0030] Benzoxazine monomers and, consequently, polymers with very favorable properties, especially in the sense of the preferred properties described above in the task description, can be produced using these amines.

[0031] Depending on the desired properties of the resulting polymers, the expert will select an amine component suitable for the cannabinoids used.

[0032] According to the invention, it is preferred that the benzoxazine mixture according to the invention is produced with an aldehyde component, preferably selected from the group consisting of formaldehyde, paraformaldehyde, benzaldehyde and furfural.

[0033] The production of the benzoxazine mixture according to the invention has proven to be particularly advantageous using these substances.

[0034] A benzoxazine mixture according to the invention is preferred, wherein the benzoxazines at least partially comprise at least one functional group selected from the group consisting of amine, thiol, thioether, alkene, epoxide, phenol, ether, and furan. These functional groups for the benzoxazine mixture (monomer mixture) according to the invention can serve to impart special properties to the polymer resulting from the subsequent polymerization reaction. The person skilled in the art has various options for incorporating the corresponding groups; for example, the selection of appropriate cannabinoids with free functional groups, as well as appropriate amines or aldehydes, could be mentioned.

[0035] Surprisingly, it has turned out that the benzoxazine mixtures according to the invention, in particular the preferred ones as described above, already possess very good properties.

[0036] It is surprising that the monomer mixtures of benzoxazine monomers sometimes even exhibit better properties than the pure benzoxazines contained in the mixture. Stability is particularly noteworthy here, especially in the temperature ranges where polymerization occurs. Furthermore, it is surprising that the benzoxazine mixtures used according to the invention also possess superior material properties compared to commercially available benzoxazines (see also examples). The same applies to the resulting polymers. It should be emphasized that a mixture of the underlying cannabinoids that closely resembles the ratios naturally occurring in the hemp plant often performs better than other mixtures.This offers not only a significant improvement in properties but also considerable advantages in terms of process simplification in the production of the benzoxazine mixture described herein, preferably bio-based, from the extraction of raw materials to its synthesis and polymerization. Accordingly, as mentioned above, full-spectrum oils from the hemp plant, preferably from the flowers, are preferred starting materials for the mixtures according to the invention.

[0037] Part of the invention also includes a polymer or oligomer produced or producible from a benzoxazine mixture according to the invention.

[0038] The production process generally follows the scheme below, whereby the specific compounds shown are not limiting: General description of the production of the cannabinoids polyben-zoxazines according to the invention

[0039]

[0040] Cannabinoids Amine Aldehyde Monomer Oligomer / Polymer

[0041] Amines can be mono, di, or multifunctional.

[0042] These polymers possess similar or even superior properties to polymers made from benzoxazine monomers used in their pure form. In other words, it is not only surprising that the benzoxazine mixtures used according to the invention exhibit comparable properties to unmixed monomers during polymerization, but in some cases, even superior properties can be achieved. Reference is made to the examples provided.

[0043] Part of the invention also includes a fiber composite material comprising fibers and a polymer according to the invention.

[0044] Fibers and semi-finished products, preferably made from hemp fibers, cellulose fibers, or natural fibers in general, are used as reinforcing fibers. Synthetic fibers made from plastics, ceramics / glass, carbon, or metallic fibers can also be used. The reinforcing fibers can be used in the form of individual fibers of varying lengths, as well as in random fiber semi-finished products (e.g., felts, nonwovens), woven fabrics, non-wovens, or rovings. The production of fiber-reinforced composites with a benzoxazine matrix can be carried out using various manufacturing processes, either in one-step or two-step procedures.

[0045] In the two-step process, the reinforcing fibers are first preferably impregnated with the matrix system in liquid, uncured form to create prepregs. This is done, for example, by vacuum infusion, calender rolling, hot melt process, or other methods for prepreg production. Alternatively, the composite material can also be manufactured in a single-step process such as resin transfer molding or vacuum infusion followed directly by curing. The curing of the matrix system is achieved by varying the parameters of temperature, time, and pressure (press pressure or atmospheric pressure), with the pressure being the primary factor influencing the composite material quality in terms of fiber volume fraction, surface finish, porosity, and the quality of the fiber-matrix bond. Suitable manufacturing processes for this include hand lay-up, compression molding, or autoclave curing.

[0046] A fiber composite material according to the invention is preferred, wherein the fibers are partly, preferably completely, derived from the hemp plant.

[0047] Such a fiber-reinforced composite material possesses favorable properties that can be readily controlled by selecting the monomers used for polymerization. The preferred variant, in which the fibers are derived from the hemp plant, is considered a particularly sustainable product, as the fibers themselves originate from natural sources. It is therefore even more advantageous if both the benzoxazines used are derived from cannabinoids from the hemp plant and the fibers themselves are derived from the hemp plant, thus enabling the utilization of large portions of the plant for the production of the fiber-reinforced composite materials according to the invention.

[0048] It is of course preferable that the corresponding raw materials come from the same plant fraction, thus making it possible to produce a high-performance lightweight material entirely within a local value chain, from the cultivation of the plant to the manufacturing of the component domestically.

[0049] Part of the invention also includes the use of an extract from hemp plants, preferably from the flowers of hemp plants, for the production of a benzoxazine mixture according to the invention.

[0050] As described above, this allows for the use of a good renewable raw material source for the production of benzoxazine monomers and, subsequently, of course, the corresponding polymers. As already mentioned above, it is preferable to use a full-spectrum oil as the extract.

[0051] Part of the invention also includes the use of a benzoxazine mixture according to the invention for the production of a polymer. Preferred applications of the polymer according to the invention are plastics, preferably as structural plastics, a matrix system for use in composite materials, in particular fiber-reinforced composites, adhesives, preferably as structural adhesives, (functional) coatings, for example, paints, insulators, in particular for thermal, acoustic and electrical insulation and / or plastics for additive manufacturing, in particular in 3D printing.

[0052] Part of the invention also includes a method for producing a benzoxazine mixture according to the invention, comprising the steps

[0053] a) Providing an extract from hemp plants, preferably from the flowers of hemp plants, comprising cannabinoids, preferably as further defined above;

[0054] b) Providing an amine component, preferably as further defined above and

[0055] c) Reacting the components provided under a) and b) preferably with an aldehyde, preferably as defined in more detail above, to form a benzoxazine mixture.

[0056] It may be preferable for the reaction to take place without the use of a solvent, as this can even lead to improved product properties.

[0057] Part of the invention also includes a method for producing a polymer or a fiber composite material according to the invention, comprising the steps

[0058] a) Providing a benzoxazine mixture and

[0059] b) Polymerizing at least some of the benzoxazines contained in the benzoxazine mixture.

[0060] To carry out this process, the person skilled in the art will take appropriate measures, particularly with regard to the desired properties of the polymers to be produced.

[0061] Reference is also made to the application areas of the polymers according to the invention described above. The invention is explained in more detail below using examples.

[0062]

[0063] The NMR experiments were performed using an AVANCE NEO 600 MHz spectrometer (Bruker Corporation, Massachusetts, USA). All spectra were referenced to the residual solvent signal of the respective NMR solvent (DMSO-d6).

[0064]

[0065] Calorimetric analyses (DSC)

[0066] DSC measurements were performed with a heating rate of 10 K / min in the temperature range of -20 to 300 °C. (Discovery DSC TA Instruments, New Castle, Delaware, United States).

[0067]

[0068] Stabilization studies (TGA)

[0069] TGA measurements were performed with a heating rate of 10 K / min in a temperature range of 35 to 800 °C in a nitrogen atmosphere. TGA Q5000 V3.17 Build 265 calorimeter (TA Instruments, New Castle, Delaware, USA).

[0070] The mass loss of the polymer / monomer is determined as a function of temperature in order to ascertain the temperature at which the polymer / monomer degrades, outgasses, or evaporates. Examples of implementation

[0071] Unless otherwise stated, all ratios, including percentages, refer to weight.

[0072] Example 1: Production of benzoxazine monomers

[0073] Ingredients used:

[0074]

[0075] dam = 4,4'diaminodiphenylmethane

[0076]

[0077] DAH = 1,6 Hexamethylenediamine

[0078]

[0079] CBN = Cannabinol

[0080] The cannabinol (CBN) was purchased as an isolate with a purity of CBN-C5- 99.2% (CBN isolate - Lemon Hemp, Hamburg, Germany).

[0081] The cannabidiol (CBD) was purchased as an isolate and contains cannabidiol CBD-C5 (99.6%) and cannabidivarin CBDV-C3 (0.2%). These are homologs of cannabidiol (CBD), with different methylene bridges (CH2 units) in their side chains (CBD isolate - Lemon Hemp, Hamburg, Germany).

[0082] All chemicals used possess a minimum purity “For synthesis’a.) Monofunctional benzoxazines

[0083] CBD-a

[0084] Solvent-free

[0085] CBD (1.05 g, 3.33 mmol), aniline (0.311 g, 3.33 mmol) and paraformaldehyde (0.221 g, 7.35

[0086] mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0087] In solvent. CBD (1 g, 3.18 mmol) was dissolved in toluene (10 ml) in a round-bottom flask. Paraformaldehyde (0.21 g, 6.99 mmol) and aniline (0.296 g, 3.18 mmol) were dissolved in

[0088] the flask was placed inside, and the temperature was increased to 110 °C for 4 hours.

[0089]

[0090] CBN-a

[0091] CBN (1.007 g, 3.24 mmol), aniline (0.302 g, 3.24 mmol) and paraformaldehyde (0.224 g,

[0092] 7.13 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0093]

[0094] b.) Difunctional benzoxazines

[0095] Dam- 4,4'DiaminodiDhenvlmethane

[0096] CBD-dam

[0097] Solvent-free: CBD (0.998 g, 3.17 mmol), 4,4'Diaminodiphenylmethane (dam) (0.315 g,

[0098] 1.59 mmol) and paraformaldehyde (0.210 g, 6.99 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0099] In solvent: CBD (0.995 g, 3.16 mmol), 4,4'Diaminodiphenylmethane (dam) (0.314 g,

[0100] 1.58 mmol) and paraformaldehyde (0.209 g, 6.96 mmol) were mixed in a round-bottom flask with toluene (10 mL) and stirred at 75 °C for 15 h and then at 1 h

[0101] Heated to 100 °C.

[0102]

[0103] CBN-dam

[0104] Solvent-free: CBN (1.02 g, 3.29 mmol), 4,4'Diaminodiphenylmethane (dam) (0.326 g,

[0105] 1.64 mmol) and paraformaldehyde (0.217 g, 7.23 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0106] In solvent: CBN (1.04 g, 3.35 mmol), 4,4'Diaminodiphenylmethane (dam) (0.332 g,

[0107] 1.68 mmol) and paraformaldehyde (0.221 g, 7.37 mmol) were mixed in a round-bottom flask with toluene (10 mL) and stirred at 75 °C for 15 h and then at 1 h

[0108] Heated to 100 °C.

[0109]

[0110] PAH - Hexamethylenediamine

[0111] CBD-DAH

[0112] In solvent: CBD (1 g, 3.18 mmol) was dissolved in toluene (10 ml) in a round-bottom flask. Paraformaldehyde (0.2 g, 6.76 mmol) and 1,6-hexamethylenediamine (DAH) (0.185 g,

[0113] 1.59 mmol) were added to the flask, and the temperature was maintained for 4 hours.

[0114] Increased to 110 °C.

[0115]

[0116] CBN-DAH

[0117] Solvent-free: CBN (2 g, 6.44 mmol), 1,6-hexamethylenediamine (DAH) (0.37 g,

[0118] 3.22 mmol) and paraformaldehyde (0.406 g, 13.52 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0119] In solvent: In a round-bottom flask, CBN (1 g, 3.22 mmol) was dissolved in toluene (10 ml). Paraformaldehyde (0.2 g, 6.76 mmol) and 1,6-hexamethylenediamine (DAH) (0.19 g,

[0120] 1.61 mmol) were added to the flask, and the temperature was maintained for 4 hours.

[0121] Increased to 110 °C.

[0122]

[0123] c.) Mixtures

[0124] Mixtures of CBD and CBN phenols were used to produce benzoxazine monomers.

[0125] It was found that mixtures with different ratios of CBD also

[0126] react to CBN, e.g. 1 :1 and 1 :0.05, to form benzoxazine monomers.

[0127] CBD-CBN 1:1

[0128] CBD-CBN-dam

[0129] Solvent-free: CBD (0.500 g, 1.59 mmol), CBN (0.494 g, 1.59 mmol), 4,4'Diaminodiphenylmethane (dam) (0.315 g, 1.59 mmol) and paraformaldehyde (0.210 g, 7.00 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0130] In solvent: CBD (0.500 g, 1.59 mmol), CBN (0.494 g, 1.59 mmol), 4,4'-Diaminodiphenylmethane (DAM) (0.315 g, 1.59 mmol) and paraformaldehyde (0.210 g, 7.00 mmol) were mixed in a round-bottom flask with toluene (10 mL) + ethanol (10 mL) and stirred.

[0131] Heated at 100°C for 20 hours. CBD-CBN-DAH

[0132] Solvent-free: CBD / CBN (1 g + 1 g, 6.40 mmol), 1,6-hexamethylenediamine (DAH)

[0133] (0.37 g, 3.2 mmol) and paraformaldehyde (0.4 g, 13.44 mmol) were mixed in a round-bottom flask.

[0134] Heated to 100 °C for 1 hour while stirring.

[0135] In solvent: CBB / CBN (1 g + 1 g, 6.44 mmol), 1,6-hexamethylenediamine (DAH) (0.37 g, 3.2 mmol) and paraformaldehyde (0.4 g, 13.44 mmol) were added to toluene (10 mL) in a round-bottom flask and heated to 110 °C for 4 h with stirring.

[0136] CBD-CBN 1:0.05 (approximate mixture as it naturally occurs in the flower of the hemp plant)

[0137] CBD-CBN-dam

[0138] Solvent-free: CBD (0.949 g, 3.02 mmol), CBN (0.049 g, 0.159 mmol), 4,4'Diaminodiphenylmethane (dam) (0.315 g, 1.59 mmol) and paraformaldehyde (0.210 g, 7.00 mmol) were heated in a round-bottom flask at 100 °C for 1 h with stirring.

[0139] In solvent: CBD (0.949 g, 3.02 mmol), CBN (0.049 g, 0.159 mmol), 4,4'-Diaminodiphenylmethane (DAM) (0.315 g, 1.59 mmol) and paraformaldehyde (0.210 g, 7.00 mmol) were mixed in a round-bottom flask with toluene (10 mL) + ethanol (10 mL) and stirred.

[0140] Heated to 100 °C for 20 hours.

[0141] Reaction equation using the example of CBD-CBN-dam

[0142]

[0143] Theoretically, three different monomers can form: symmetrical ones: CBD-dam-CBD and CBN-dam-CBN, and asymmetrical ones: CBD-dam-CBN.

[0144] d.) Characterization of the monomers

[0145] NMR: The important signals indicative of benzoxazine ring formation were detected using 2D NMR spectroscopic imaging. Furthermore, it was confirmed that the double bonds in the monomer were still present.

[0146] Spectroscopic methods made it possible to identify the respective monomer structures in the mixtures.

[0147] Fig. 1 shows an NMR spectrum using the cannabinoids CBD and CBN with DAH (1,6-hexamethylenediamine) as an example. Example 2

[0148] Polymerization of benzoxazine monomers

[0149] The polymerization of the monomers took place under the following curing conditions:

[0150] hardening program

[0151] Temperature °C Time in hours

[0152] 120 1

[0153] 120-150 0.25

[0154] 150 2

[0155] 150-180 0.25

[0156] 180 4

[0157] This temperature profile was chosen for all monomers to ensure comparability. Individual adjustments can be made for each specific monomer or monomer mixture.

[0158] General structural formula for the polymerization of benzoxazine monomers to polyben-zoxazine.

[0159]

[0160] CBD-a

[0161] 5

[0162]

[0163] CBD-dam

[0164]

[0165] 5 CBN-dam

[0166]

[0167] CBD-DAH

[0168]

[0169] Blends (CBD-dam-CBD: CBN-dam-CBN: CBD-dam-CBN)

[0170]

[0171] Example 3 calorimetric investigations

[0172] Calorimetric investigations before and after polymerization of the monomer mixtures revealed that they polymerize and exhibit constant and / or even higher glass transition temperatures than polymers made from unmixed monomers. DSC analysis of the polymerized monomers CBD / CBN-DAH and the 1:1 mixture is shown in Figures 2 and 3.

[0173] Figure 2 shows the results of the calorimetric investigations of CBD- / CBN-DAH as a pure mixture and as a 1:1 mixture (each after polymerization). Figure 3 shows the results of the calorimetric investigations of CBD- / CBN-DAM and a 1:0.05 mixture (each after polymerization).

[0174] Due to the double bonds or aromatic groups present in the monomer, additional cross-linking sites can form.

[0175] Figure 2 clearly shows that the glass transition temperature of the polymers obtained from the monomeric mixture CBD- / CBN-DAH in a 1:1 ratio is significantly increased.

[0176] Figure 3 also shows the CBD / CBN dam mixture ratio of 1:0.05 as the starting material; this ratio roughly corresponds to the natural ratio found in the hemp plant. Furthermore, the resulting glass transition temperature for the polymer formed from this mixture is higher than that of the 1:00 mixture ratio of the corresponding monomers. This, too, is a surprising and unpredictable effect.

[0177] Example 4: Thermal stability of the mixtures with respect to the individual monomers and polymers thereof

[0178] The thermal stability of the monomers and polymers was analyzed in the uncured and cured states using a TGA.

[0179] As can be seen from the curves of mass loss versus temperature, the cannabinoid polymers all exhibit similar thermal properties (see Fig. 4 and 5).

[0180] Figure 4 shows the mass loss of the polymerized benzoxazines with increasing temperature (10 Calvin per minute) for the polymers made from the respective monomers or monomer mixtures mentioned.

[0181] Figure 5 presents a representation analogous to Figure 4, except that different monomers or monomer mixtures were examined.

[0182] Polymers based on a cannabinoid mixture (CBD + CBN 1:1 or 1:0.05) exhibit the same or even increased thermal stability compared to pure polymers (CBD or CBN only). In comparison with a commercially available bio-based benzoxazine (FB602, furfural as the aldehyde component and cardanol as the phenol component with an effective bio-content of 59%, Bitrez Ltd., Standish, UK), the cannabinoid-based benzoxazines show significantly increased thermal stability, particularly in the ranges of 1% (approx. 107°C increase) and 5% (approx. 30°C to 50°C increase) mass loss (see Fig. 6).

[0183] Figure 6 shows the comparison of the temperatures of the benzoxazines at 1%, 5% and 10% mass loss, determined in the TGA, for the monomers or monomer mixtures mentioned.

[0184] When comparing the thermal analyses (TGAs) of the cannabinoid monomers with each other and with the commercial FB602 monomer, it becomes clear that the cannabinoid monomers only exhibit a significant mass loss above the maximum polymerization temperature (180°C) (see Fig. 7).

[0185] Figure 7 presents the results of the thermal analysis for the mass loss of the cannabinoid monomers compared to the commercial monomer FB602.

[0186] This advantage applies particularly to the monomers that were synthesized without solvents and exhibit significantly improved thermal stability compared to the FB602 monomer.

[0187] This highlights a further advantage of cannabinoid monomers in general, and of the monomers from cannabinoid mixtures in particular, compared to the prior art, as the reduced mass loss during polymerization indicates reduced gas formation and thus reduced polymer porosity. The comparatively high mass loss of the FB602 monomer suggests the onset of the monomer decomposition process during polymerization, which is not observed in the monomers from cannabinoid mixtures. This was also evident in a significant difference in the porosity of the polymers from FB602 and the mixture containing 5% CBN and 95% CBD. No foaming of the polymer was observed during polymerization of the monomers, a phenomenon typically seen in bio-based benzoxazines and a common challenge in the curing of bio-based phenols / benzoxazines.Another aspect is the less step-dependent curve of mass loss during curing compared to the FB602 monomer, which results in further advantages of the cannabinoid monomers for the production of structural and joining components due to their more constant thermal properties and lower curing shrinkage.

[0188] The observations described in the previous paragraph can also be confirmed by examining the polymer surface or sample fracture surface. While the polymer surface of polymers based on the FB602 monomer exhibits significant unevenness, the polymers based on the monomer mixture of cannabinoids (CBD and CBN) show virtually no surface structuring.

[0189] The situation is analogous for sample fracture surfaces. The fracture surface of the polymers based on FB602 is three-dimensionally structured and porous, while that of the polymers based on the monomeric mixture is smooth without any bulges.

Claims

- 27 - Patent claims 1. Benzoxazine mixture, manufactured or manufactureable from a mixture of cannabinoids.

2. Benzoxazine mixture according to claim 1, wherein at least a part of the cannabinoids is a cannabinoid or several cannabinoids in the form of a carboxylic acid or carboxylic acids from the biosynthesis of the hemp plant.

3. Benzoxazine mixture according to claim 1 or 2, at least a part of the cannabinoids is a cannabinoid or several cannabinoids from the biosynthesis of the hemp plant in neutral, decarboxylated form.

4. Benzoxazine mixture according to any of the preceding claims, wherein the benzoxazine mixture comprises or consists of at least 3, more preferably at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 15, at least 20, at least 40, at least 60, at least 80 and particularly preferably at least 100 cannabinoids.

5. Benzoxazine mixture according to any one of the preceding claims, wherein at least 20 wt.%, preferably at least 30 wt.%, further preferably at least 40 wt.% are jointly selected from the group consisting of CBDA (cannabidiolic acid), CBDVA (cannabidivarinic acid), CBNA (cannabinolic acid), CBGA (cannabigerolic acid), CBCA (cannabichromenic acid), CBLA (cannabicyclolic acid), THC (tetrahydrocannabinol), δ9-THC (delta-9-tetrahydrocannabinol), δ8-THC (delta-8-tetrahydrocannabinol), CBD (cannabidiol), CBG (cannabigerol), CBN (cannabinol), CBC (cannabichromene), THCV (tetrahydrocannabivarin), CBDV (cannabidivarin), CBL (cannabicyclol), CBE (cannabielsoin), CBT (cannabitriol), isocannabinoids, CBCN (cannabichromene varin), THCA (tetrahydrocannabinolic acid) C4 isomer and THCA C3 isomer.

6. Benzoxazine mixture according to one of the preceding claims, wherein at least 20 wt.%, preferably at least 30 wt.%, further preferably at least 40 wt.% are derived from a cannabinoid and its homologs selected from the group consisting of CBDA, CBDVA, CBNA, CBGA, CBCA, CBLA, THC, d9-THC, d8-THC, CBD, CBG, CBN, CBC, THCV, CBDV, CBL, CBE, CBT, isocannabinoids, CBCN, THCA, THCA C4 isomer and THCA C3 isomer, wherein further preferably the said weight fraction is derived from only two, further preferably from only one of the aforementioned cannabinoids.

7. Benzoxazine mixture according to one of the preceding claims, wherein the cannabinoids were reacted with at least one amine selected from the group consisting of aromatic and non-aromatic amines, which may each be mono-, di- or multifunctional, and mixtures of the corresponding amines, preferably selected from the group consisting of aniline, diaminodiphenylmethane, hexamethylenediamine, polyetheramines, furfurylamine, 2,5-furandimethanamine, wherein it is preferred that the cannabinoids were reacted with only one amine compound.

8. Benzoxazine mixture according to any of the preceding claims, wherein the benzoxazines at least partially comprise at least one functional group selected from the group consisting of amine, thiol, thioether, alkene, epoxide, phenol, ether and furan.

9. Polymer or oligomer produced or producible from a benzoxazine mixture according to any one of the preceding claims.

10. Fiber composite material comprising fibers and a polymer according to claim 9.

11. Fiber composite material according to claim 10, wherein the fibers are partly, preferably entirely, derived from the hemp plant.

12. Use of an extract from hemp plants, preferably from the flowers of hemp plants, for the production of a benzoxazine mixture according to any one of claims 1 to 8.

13. Use of a benzoxazine mixture according to any one of claims 1 to 8 for the production of a polymer.

14. A method for producing a benzoxazine mixture according to any one of claims 1 to 8, comprising the steps: a) Providing an extract from hemp plants, preferably from the flowers of hemp plants, comprising cannabinoids, preferably as further defined in any one of claims 2 to 6; b) Providing an amine component, preferably as further defined in claim 7 and c) Reacting the components provided under a) and b) preferably with an aldehyde to form a benzoxazine mixture, 15. A method for producing a polymer according to claim 9 or for producing a fiber composite material according to claim 10 or 11, comprising the steps a.) Providing a benzoxazine mixture according to any one of claims 1 to 8 and b.) Polymerizing at least some of the benzoxazines contained in the benzoxazine mixture.

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