MATRIX RESIN FOR THE PRODUCTION OF FIBER COMPOSITE MATERIALS

Description

[0001] The present invention relates to matrix resins for the production of fiber composite materials.

[0002] Glass or carbon fiber-reinforced composites for high-performance applications are primarily manufactured using thermosetting resin systems. Unsaturated polyester resins account for the largest market share, followed by epoxy resins and vinyl ester resins. Fiber composites based on epoxy resins generally exhibit the best mechanical properties, while components based on unsaturated polyester resins exhibit the poorest. However, unsaturated polyester resins are less expensive than epoxy resins and easier to process because they are crosslinked with peroxides. Vinyl ester resins represent a compromise in terms of performance, processability, and cost.

[0003] These thermosetting resin systems are all based on oil-based raw materials; polyester resins and vinyl ester resins also contain large amounts of styrene, a substance that poses a risk to occupational hygiene.

[0004] For a long time, there has been a search for bio-based matrix resins that are easy to process, exhibit good mechanical properties, and are reasonably priced. However, the resin systems currently available do not meet these requirements – polyfurfuryl alcohol is one example. Polyfurfuryl alcohol crosslinks by releasing water and quickly becomes highly viscous. A low-viscosity polyfurfuryl alcohol resin that can be processed by infusion typically contains a large amount of water. Bubbles form when this resin cures. In addition, corresponding thermosets and fiber composites are very porous.

[0005] Bio-based reactive materials have long been known, both in the field of epoxy chemistry (e.g., epoxidized soybean oils or epoxidized cashew shell oil) and in the field of polyester chemistry (e.g., cardanol derived from cashew shell oil, rosin resins, or unsaturated oleic acids). These are often used only as formulation components, as in pure form they lead to polymers with poor mechanical properties.

[0006] Vanillin is now produced on an industrial scale and very inexpensively from lignin, a waste product of the paper industry. In 2014, the production already exceeded 17,000 tons. Vanillin is known to be used as a flavoring agent in the food industry and is therefore non-toxic. Methacrylated vanillin (vanillin methacrylate) is also well known. Both its production and its use in composites or 3D printing have been previously described, for example, in Stanzione III et al., "Vanillin-based resin for use in composite applications," Green Chem., 2012, 14, 2346-2352, and Bassett et al., "Vanillin-Based Resin for Additive Manufacturing," ACS Sustainable Chem. Eng. 2020, 8, 5626-5635.

[0007] However, in the field of fiber composites, two problems have arisen with the use of methacrylated vanillin. Firstly, methacrylated vanillin cannot be readily processed in typical fiber composite operations because it is a solid. Although methacrylated vanillin can be dissolved in acrylate monomers frequently used as reactive diluents, such as 1,6-hexanediol diacrylate (HDDA), as soon as this solution is mixed with the hardener and accelerator required for processing, the methacrylated vanillin recrystallizes, making further processing impossible. Secondly, cured methacrylated vanillin is very brittle and therefore unsuitable as a matrix resin for fiber composites.

[0008] Mixtures of methacrylated vanillin with acrylated, epoxidized soybean oil are also known from the state of the art, for example, from Zhang, C. et al., "Biorenewable Polymers based on acrylated epoxidized soybean oil and methacrylated vanillin," Materials Today Communications 5 (2015) 18-22 . However, the mechanical properties of the cured mixtures are not sufficient for the production of fiber composite components.

[0009] Experiments conducted by the inventors have shown that mixtures of methacrylated vanillin and cardanol, which, as already mentioned, is frequently used in polyester chemistry, are not storage-stable. The methacrylated vanillin also crystallizes.

[0010] Experiments by the inventors have further shown that mixtures of methacrylated vanillin, cardanol, and acrylate monomers, such as HDDA, appear to exhibit better storage stability as reactive diluents. However, when mixed with hardener and accelerator, spontaneous crystallization also occurs, making processing impossible. JS 4 990 591 A discloses a composition containing an aldehyde, a phenolic compound, and aminoethylpiperazine as a diamine, as well as acrylic acid. US 4 990 591 A refers to storage-stable resins (column 10, line 59 to column 11, line 27).

[0011] The object of the present invention was therefore to overcome at least one of the aforementioned disadvantages.

[0012] Surprisingly, it has now been found that a composition containing at least one aldehyde (A), at least one phenolic compound (B) and at least one amine (C) carrying at least two amino groups selected from the group consisting of primary and secondary amino groups, wherein at least one of these compounds carries at least one (meth)acrylate group, solves this problem.

[0013] This composition is preferably a resin, also called a resin system, that can be cured to form a thermoset (a so-called thermosetting resin system). This resin exhibits a very favorable property profile for the production of composite materials, in particular fiber composites. The resin is storage-stable, has a low viscosity and can be easily mixed and further processed with common hardeners and accelerators. After the addition of hardeners and accelerators, the resin has a sufficiently long pot life (processing time) of approximately 4 hours, which is extremely important in practice. The resin can be pre-cured at moderate temperatures of 40 °C to 100 °C, e.g. 60 °C. After post-curing at a temperature of >100 °C to 200 °C, e.g. 140 °C, the resin exhibits very good mechanical properties and is not brittle.It is therefore ideally suited for the production of thermosets and fiber composites.

[0014] A first subject of the invention is therefore a composition containing at least one aldehyde (A), at least one phenolic compound (B) and at least one amine (C) carrying at least two amino groups selected from the group consisting of primary and secondary amino groups, wherein at least one of these compounds carries at least one (meth)acrylate group.

[0015] Another object of the invention is a fiber-reinforced composition containing at least one fiber material, preferably made from one or more renewable raw materials, and the composition according to the invention.

[0016] Yet another object of the invention is a process for curing the composition according to the invention or the fiber-reinforced composition according to the invention, characterized in that the curing takes place via a radical and a non-radical curing mechanism, and preferably comprises the following steps: (i) thermal pre-curing at a temperature of 40°C to 100°C, in particular over a period of 1 h to 8 h, and / or photochemical pre-curing by actinic radiation, in particular UV light; (ii) thermal post-curing at a temperature of >100°C to 200°C, in particular over a period of 1 h to 8 h.

[0017] Yet another object of the invention is a fiber composite material or thermoset obtainable by the process according to the invention.

[0018] Advantageous embodiments of the invention are specified in the dependent claims, the examples, and the description. Furthermore, it is expressly pointed out that the disclosure of the subject matter of the present invention includes all combinations of individual features of the present or subsequent description of the invention and the patent claims. In particular, embodiments of a subject matter according to the invention mutatis mutandis also for the embodiments of the other objects according to the invention.

[0019] The subject matter of the invention and its preferred embodiments are described below by way of example, without intending to limit the invention to these exemplary embodiments. If ranges, general formulas, or classes of compounds are specified below, these are intended to encompass not only the corresponding ranges or groups of compounds explicitly mentioned, but also all subranges and subgroups of compounds that can be obtained by removing individual values (ranges) or compounds. If documents are cited within the scope of this description, their entire content is intended to be part of the disclosure of the present invention.

[0020] Unless otherwise stated, any measured values, parameters, or material properties specified below that are determined by measurement are measured at 25 °C and preferably at atmospheric pressure. At atmospheric pressure is defined as a pressure of 101325 Pa.

[0021] The word component "(meth)acryl" stands for "methacrylic" and / or "acrylic." Accordingly, the term "(meth)acrylate group" stands for a methacrylate group and / or an acrylate group. A methacrylate group is understood to be a methacrylic acid ester group, and an acrylate group is understood to be an acrylic acid ester group.

[0022] As already explained above, the composition according to the invention contains at least one aldehyde (A), at least one phenolic compound (B) and at least one amine (C) carrying at least two amino groups selected from the group consisting of primary and secondary amino groups, wherein at least one of these compounds carries at least one (meth)acrylate group.

[0023] The (meth)acrylate group is required for the radical curing mechanism. The aldehyde (A), the phenolic compound (B), and the amine (C) are also required for the non-radical curing mechanism, which, without being bound by any theory, proceeds via a Betti / Mannich reaction.

[0024] It is preferred that at least one of the compounds (A), (C), and (B) is produced from renewable raw materials or is a renewable raw material. It is particularly preferred that at least one aldehyde (A) and one phenolic compound (B) are produced from renewable raw materials and / or are renewable raw materials. Depending on the composition of the mixture, a mass fraction of bio-based raw materials of between 75 and 96%, based on the total mass of the composition, can be achieved.

[0025] It is preferred that at least one or all aldehydes (A) carry at least one (meth)acrylate group. It is further preferred that at least one or all aldehydes (A) are aromatic. It is therefore likewise preferred that at least one or all aldehydes (A) are aromatic and carry at least one (meth)acrylate group. It is further preferred that at least one aldehyde (A) is (meth)acrylated vanillin (vanillin (meth)acrylate). It is particularly preferred that exclusively (meth)acrylated vanillin (vanillin (meth)acrylate) is used as aldehyde (A). The terms "(meth)acrylated vanillin" and "vanillin (meth)acrylate" are used synonymously in the context of the present invention. "(meth)acrylated vanillin" or "vanillin (meth)acrylate" is 4-(meth)acryloxy-3-methoxybenzaldehyde, the (meth)acrylic acid ester of 4-hydroxy-3-methoxybenzaldehyde (vanillin).Methacrylated vanillin (vanillin methacrylate, 4-methacryloxy-3-methoxybenzaldehyde) has a structure according to the formula (I): . Acrylated vanillin (vanillin acrylate, 4-acryloxy-3-methoxybenzaldehyde) has a structure as shown in formula (II):

[0026] It is particularly preferred that the at least one aldehyde (A) is or comprises methacrylated vanillin (vanillin methacrylate, 4-methacryloxy-3-methoxybenzaldehyde). This compound is available, for example, under the name Visiomer® VALMA from Evonik.

[0027] The composition according to the invention further contains at least one phenolic compound (B). A phenolic compound is understood here to be a compound that bears one or more hydroxyl groups on one or more aromatic systems, also referred to as aromatic ring systems. These hydroxyl groups are thus each bonded to a carbon atom, which in turn is part of an aromatic system. The simplest example of a phenolic compound is phenol (hydroxybenzene).

[0028] It is preferred that at least one or all of the phenolic compounds (B) are ethylenically unsaturated compounds. An ethylenically unsaturated compound is understood here to be a compound that contains at least one C=C double bond that is not part of an aromatic system. It is therefore preferred that the phenolic compound (B) contains at least one C=C double bond that is not part of an aromatic system. Without being bound to any theory, it is suspected that the C=C double bonds are at least partially involved in the radical curing mechanism.

[0029] It is particularly preferred that at least one or all of the phenolic compounds (B) are cardanols. Cardanols are phenolic compounds obtained by decarboxylation of anacardic acids. Anacardic acids, in turn, are the main component of cashew shell liquid or cashew shell oil, which in turn is a by-product of cashew processing. For the purposes of the present invention, anacardic acids are understood to mean compounds of formula (III) and cardanols are understood to mean compounds of formula (IV). where R is each independently a saturated or unsaturated hydrocarbon radical.

[0030] The anacardic acids in cashew shell oil and the cardanols derived from them generally have a hydrocarbon residue R with 15 carbon atoms, although the degree of saturation can vary. The cardanol obtained from cashew shell oil contains approximately 41% triunsaturated cardanol, approximately 34% monounsaturated cardanol, approximately 22% diunsaturated cardanol, and approximately 2% saturated cardanol, each expressed as a percentage by mass based on the total mass of the cardanols.

[0031] It is therefore preferred that the radical R in formula (III) or (IV) is a hydrocarbon radical having 15 carbon atoms. It is further preferred that the radical R in formula (III) or (IV) has zero, one, two, or three C=C double bonds.

[0032] It is therefore particularly preferred that the radical R in formula (III) and (IV) is each independently a radical having 15 carbon atoms and has no, one, two or three C=C double bonds.

[0033] Since the C=C double bonds can undergo radical polymerization, it is further preferred that the radical R is each independently a radical with at least one C=C double bond.

[0034] It is therefore preferred that the radical R is each independently a radical having at least one C=C double bond and / or having 15 carbon atoms, in particular a radical having at least one C=C double bond and having 15 carbon atoms.

[0035] Anarcadaic acid, which gives its name to the group of anarcardic acids and is the main component of anacardic acids in cashew nut shell oil, for example, has a radical R of the formula (V). where the dashed line represents the covalent bond to the benzene ring. R in formulas (III) and (IV) is therefore preferably a radical of formula (V). Also preferred are those R radicals that are derived from a radical of formula (V) (formally) by hydrogenation / saturation of one, two, or all three C=C double bonds.

[0036] Cardanols are commercially available. Particular preference is given to Cardanol NX-2026 (Cardolite), a diunsaturated cardanol of formula (VI) where R = -C 7 H 14 -CH=CH-CH 2 -CH=CH-C 3 H 7 . Preferably, R in formulas (III) and (IV) is R = -C 7 H 14 -CH=CH-CH 2 -CH=CH-C 3 H 7 .

[0037] The composition according to the invention further contains at least one amine (C) bearing at least two amino groups selected from the group consisting of primary and secondary amino groups. Primary or secondary amino groups are necessary for a Mannich reaction or a Betti reaction. Tertiary amino groups, however, cannot be reacted in a Mannich reaction or a Betti reaction.

[0038] The composition according to the invention preferably contains at least one amine (C) which carries at least two primary amino groups.

[0039] It is further preferred that the amine (C) is aromatic. Aromatic amines are amines that carry one or more amino groups, each bonded to a carbon atom, which in turn is part of an aromatic system. The simplest example of an aromatic amine is aniline (phenylamine, aminobenzene).

[0040] It is further preferred that the amine (C) is a dianiline. A dianiline is understood to be a compound that bears two aminophenyl radicals, in particular two 4-aminophenyl radicals. According to the invention, the amino groups are selected from the group of primary and secondary amino groups. Therefore, the amine (C) is particularly preferably a dianiline with primary amino groups.

[0041] It is further preferred that at least one amine (C) is selected from the group consisting of substituted or unsubstituted 4,4'-isopropylidenedianilines and substituted or unsubstituted 4,4'-methylenedianilines and substituted or unsubstituted 4,4'-sulfonyldianilines, preferably from the group consisting of 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2,6-diisopropylaniline), and 4,4'-diaminodiphenylsulfone. At least one amine (C) is particularly preferred as 4,4'-diaminodiphenylsulfone.

[0042] Dianilines are commercially available. For example, 4,4'-methylenebis(2,6-diethylaniline) is available under the name Lonzacure®< M-DEA (Lonza), 4,4'-methylenebis(2,6-diisopropylaniline) under the name Lonzacure®< M-DIPA (Lonza), and 4,4'-diaminodiphenylsulfone under the name Aradur®< 976-1 (Huntsman).

[0043] It is preferred that the composition according to the invention additionally contains at least one (meth)acrylate (D). A (meth)acrylate is understood here to be a compound that carries one or more (meth)acrylate group(s), i.e. one or more methacrylic acid ester group(s) and / or acrylic acid ester group(s). The (meth)acrylate (D) serves as a reactive diluent and / or crosslinker. As a reactive diluent, the (meth)acrylate (D) can have one or more (meth)acrylate group(s). As a crosslinker, the (meth)acrylate (D) must carry at least two (meth)acrylate groups. If the (meth)acrylate (D) is to be used both as a reactive diluent and as a crosslinker, it is therefore necessary for the (meth)acrylate (D) to have at least two (meth)acrylate groups. It is therefore preferred that at least one or all (meth)acrylates (D) carry at least two (meth)acrylate groups.It is further preferred that at least one or all (meth)acrylates (D) carry two to six (meth)acrylate groups. The (meth)acrylate (D) preferably consists only of the elements carbon, hydrogen, oxygen, and nitrogen, in particular only of the elements carbon, hydrogen, and oxygen. Suitable (meth)acrylates (D) are described in . European Coatings Tech Files, Patrick Glöckner et al., "Radiation Curing: Coatings and Printing Inks," 2008, Vincentz Network, Hanover, Germany.

[0044] Preferably, at least one (meth)acrylate (D) is selected from the group consisting of trimethylolpropane triacrylate (TMPTA), tripropylene glycol diacrylate (TPGDA), dipropylene glycol diacrylate (DPGDA), isobornyl acrylate (IBOA), lauryl acrylate, dodecyl acrylate, 1,6-hexanediol diacrylate (HDDA), tridecyl acrylate, pentaerythritol triacrylate, polyethylene glycol diacrylate and their ethoxylated and / or propoxylated derivatives.

[0045] It is also preferred that at least one (meth)acrylate (D) is selected from the group consisting of the (meth)acrylic acid esters of vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol), guaiacol, and creosol, as described, for example, by Holmberg, AL et al. in "Softwood Lignin-Based Methacrylate Polymers with Tunable Thermal and Viscoelastic Properties", Macromolecules 2016, 49, 1286-1295. These compounds, like (meth)acrylated vanillin, are compounds produced from lignin as a renewable raw material.

[0046] Suitable (meth)acrylates (D) are commercially available under the designation Ebecryl ®< TMPTA (Allnex SA, Germany), Ebecryl ®< OTA480 (a propoxylated glyceryl triacrylate, Allnex SA, Germany), Ebecryl ®< TPGDA (Allnex SA, Germany), Ebecryl ®< DPGDA (Allnex SA, Germany), Ebecryl ®< 892 (Allnex SA, Germany), Ebecryl ®< 11 (a polyethylene glycol diacrylate, Allnex SA, Germany), Ebecryl ®< 45 (Allnex SA, Germany), PETIA (a mixture of pentaerythritol tri- and tetraacrylate, Allnex SA, Germany), Ebecryl ®< 150 (a diacrylate based on bisphenol A, Allnex SA, Germany), Ebecryl ®< 605 (a mixture of 80% bisphenol A diepoxyacrylate and 20% TPGDA, Allnex SA, Germany), Ebecryl ®< 40 (an ethoxylated and propoxylated pentaerythritol tetraacrylate, Allnex SA, Germany), Laromer ®< TMPTA (BASF, Germany), Miramer ®< M200 (HDDA, Rahn AG, Germany), Miramer ®< M220 (TPGDA, Rahn AG, Germany),Miramer ®< 3130 (an ethoxylated trimethylolpropane triacrylate, Rahn AG, Germany), SR 415 (an ethoxylated trimethylolpropane triacrylate, Sartomer, France), SR 489 (tridecyl acrylate, Sartomer, France) and Sarbio ®< 5101 (dodecyl acrylate, Arkema, France).

[0047] Suitable (meth)acrylates (D) are also commercially available from Evonik Operations GmbH (Germany) under the VISIOMER ®< product line. Preferred compounds are glycerol formal methacrylate (VISIOMER ®< GLYFOMA), diurethane dimethacrylate (VISIOMER ®< HEMA TMDI), butyl diglycol methacrylate (VISIOMER ®< BDGMA), polyethylene glycol 200 dimethacrylate (VISIOMER ®< PEG200DMA), trimethylolpropane methacrylate (VISIOMER ®< TMPTMA), tetrahydrofurfuryl methacrylate (VISIOMER ®< THFMA), isobornyl methacrylate (VISIOMER ®< Terra IBOMA), isobornyl acrylate (VISIOMER ®< IBOA), a methacrylic acid ester of fatty alcohols with an average of 13.0 carbon atoms (VISIOMER ®< Terra C13-MA) or with an average of 17.4 carbon atoms (VISIOMER ®< Terra C17.4-MA).

[0048] Particularly preferably, the composition contains at least one (meth)acrylate (D) selected from the group of diol- and triol-based di- and trifunctional acrylates, in particular 1,6-hexanediol diacrylate (HDDA).

[0049] It is preferred that the composition according to the invention further contains at least one initiator (E).

[0050] The initiator (E) of the composition according to the invention is a compound that forms radicals when exposed to an external trigger. This trigger can be actinic radiation, preferably UV light and / or visible light, or heat. Accordingly, the initiators (E) can be initiators for photochemical radical curing or polymerization (photoinitiators) and / or initiators for thermal radical curing or polymerization (thermal initiators).

[0051] Organic peroxides are preferably used as thermal initiators, such as 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (e.g. LUPEROX 101 ®< ), dilauroyl peroxide (e.g. LUPEROX LP ®< ), dibenzoyl peroxide (e.g. LUPEROX A98 ®< ) and bis(tert-butyldioxyisopropyl)benzene (e.g. VulCUP R ®< ) from Arkema (France) or Peroxan BP powder 50 W from Pergan GmbH (Germany), a powder containing approx. 40-50 wt.% dibenzoyl peroxide and approx. 40-50 wt.% dicyclohexyl phthalate. Preferred thermal initiators are furthermore ketone peroxides such as methyl ethyl ketone peroxide, diacyl peroxides such as benzoyl peroxide, hydroperoxides such as cumene hydroperoxide as well as peroxyketals, dialkyl peroxides, peroxydicarbonates and peroxyesters, as well as inorganic peroxides such as peroxydisulfates, including sodium persulfate (Na 2 S 2 O 8 ), potassium persulfate (K 2 S 2 O 8 ), and ammonium persulfate ((NH 4 ) 2 S 2 O 8 ), and furthermore also azobisisobutyronitrile (AIBN).

[0052] Suitable photoinitiators include all photoinitiators known to the person skilled in the art, including Norrish type I and Norrish type II photoinitiators. This includes the commonly used UV photoinitiators, such as acetophenones (e.g. diethoxyacetophenone) and phosphine oxides (e.g. diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, phenyl-bis-(2,4,6-trimethylbenzoyl)phosphine oxide (PPO) and bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide). Particular preference is given to Norrish type 1 photoinitiators, such as benzophenone, benzoin, α-hydroxyalkylphenone, acylphosphine oxide or derivatives thereof. Suitable photoinitiators are described, for example, in " A Compilation of Photoinitiators Commercially available for UV today" (K. Dietliker, SITA Technology Ltd., London 2002).

[0053] It is preferred that the composition according to the invention further contains at least one accelerator (F).

[0054] If the composition contains a thermal initiator, it is preferred that it contain an accelerator (F) that accelerates this radical thermal curing. Examples include organic acid metal salts, such as cobalt naphthenate, and tertiary aromatic amines, preferably tertiary aromatic amines such as N,N-dimethylaniline, N,N-diethylaniline, and N,N-dimethylparatoluidine.

[0055] If the composition contains a photoinitiator, it is preferred that it contain an accelerator (F) that accelerates this photochemical radical curing. Such an accelerator is also referred to as a photosensitizer. Examples include amines such as n-butylamine, triethylamine, N-methyldiethanolamine, piperidine, N,N-dimethylaniline, and triethylenetetramine; sulfur compounds such as S-benzylisothiuronium p-toluenesulfinate, N,N-dimethyl-p-aminobenzonitrile; and phosphorus compounds such as sodium diethylthiophosphate.

[0056] It is particularly preferred that the composition according to the invention contains at least one tertiary amine, preferably at least one tertiary aromatic amine, in particular N,N-diethylaniline, as accelerator (F). N,N-Diethylaniline is commercially available, for example, in solution under the name PERGAQUICK A3X from Pergan GmbH (Germany). The solution contains approximately 5-10 wt.% N,N-diethylaniline and approximately 80-90 wt.% 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate.

[0057] It is preferred that the composition according to the invention further contains at least one further additive (G). The additive (G) is preferably a substance with which the properties of the uncured or cured composition can be specifically adjusted. These can be, for example, dyes, pigments, rheology agents, and impact modifiers, but also nanoscale fillers that can be processed using infusion and injection methods. Examples of these are acrylate-functional acrylonitrile-butadiene copolymers such as Hypro®< VTBNX 1300x43 from Huntsman, Tegomer®< M-Si 2650 from Evonik Operations, nanosilica, and nanoaluminates.

[0058] It is preferred that the composition according to the invention contains or consists of the following components, based on the total mass of the composition: one or more aldehyde(s) (A) in a total mass fraction of 60% to 90%, preferably 65% to 85%, in particular 70% to 80%; one or more phenolic compound(s) (B) in a total mass fraction of 1% to 25%, preferably 3% to 20%, in particular 5% to 15%; one or more amine(s) (C) in a total mass fraction of 1% to 20%, preferably 2% to 10%, in particular 3% to 5%; one or more (meth)acrylate(s) (D) in a total mass fraction of 1% to 25%, preferably 3% to 20%, in particular 5% to 15%; one or more initiator(s) (E) in a total mass fraction of 0.1% to 5%, preferably 0.2% to 4%, in particular 0.3% to 1%; one or more accelerators (F) in a total mass fraction of 0% to 10%, preferably 0.01% to 5%, in particular 0.02% to 2%; one or more additive(s) (G) in a total mass fraction of 0% to 10%, preferably 0.01% to 5%, in particular 0.02% to 2%.

[0059] The mandatory and optional components of the composition according to the invention, i.e., aldehydes (A), phenolic compounds (B), amines (C), (meth)acrylates (D), initiators (E), accelerators (F), and additives (G), are all different from one another. In the event that a compound can be assigned in principle to two or more of the aforementioned groups (A), (B), (C), (D), (E), (F), and (G), this compound should be assigned to the relevant group that is mentioned first in the order given above, unless explicitly deviated from this rule. Therefore, if a compound can be assigned, for example, to one of the groups (B), (D), and (G), it should be assigned to the first of the relevant groups, in this example, (B). A compound is therefore not assigned to more than one of the groups (A), (B), (C), (D), (E), (F), and (G).

[0060] The composition according to the invention can be used in electronics, as a potting compound, or in stereolithography (SLA). However, the composition according to the invention is particularly suitable for the production of fiber-reinforced compositions and the fiber composite materials produced therefrom.

[0061] A further object of the invention is therefore a fiber-reinforced composition containing at least one fiber material, preferably made from one or more renewable raw materials, and the composition according to the invention.

[0062] The fiber materials are preferably single filaments, fiber bundles containing single filaments, threads containing single filaments, or fiber bundles. Furthermore, the fiber materials are preferably products such as non-crimp fabrics and woven fabrics containing single filaments, fiber bundles, or threads. Non-crimp fabrics containing fiber bundles are particularly preferred. In the case of woven fabrics, these are preferably linen weaves. Preferred non-crimp fabrics are constructed from layers, whereby the layers can be aligned in the same direction (uniaxial) or aligned in different directions (multiaxial). The advantage of non-crimp fabrics is that the fibers or fiber bundles of the layers are not bent by the braiding process. This provides a higher force-absorbing capacity. The fiber materials are preferably glass fiber, mineral fiber, natural fiber, and / or polymer fiber materials, preferably natural fiber materials, in particular natural fibers.Even more preferably, the fiber materials are scrims made of glass fiber, mineral fiber, natural fiber, and / or polymer fiber materials; in particular, the fiber materials are scrims made of natural fibers. The fiber materials are preferably manufactured raw products, as purified materials, or already coated; purified fiber materials are preferably used. Cleaning is preferably material-dependent; a preferred cleaning method is thermal treatment, particularly preferably irradiation with an IR radiator. If desired, the thermal treatment can be carried out under protective gas. This cleaning step primarily removes water, which is almost always present in natural fibers and is disruptive during subsequent processing into the fiber composite. It is preferred that the fiber material is selected from the group consisting of flax fibers, hemp fibers, jute fibers, kenaf fibers, ramie fibers, sisal fibers, and wood fibers.The fibers can be specifically modified by ultrasonic processing so that they receive reproducible technical properties through standardized processing processes.

[0063] The composition according to the invention and the fiber-reinforced composition according to the invention can be cured using a special process. These compositions are cured via both a radical and a non-radical curing mechanism.

[0064] A further subject of the invention is therefore a process for curing the composition according to the invention or the fiber-reinforced composition according to the invention, characterized in that the curing takes place via a radical and a non-radical curing mechanism and preferably comprises the following steps: (i) thermal pre-curing at a temperature of 40°C to 100°C, in particular over a period of 1 h to 8 h, and / or photochemical pre-curing by actinic radiation, in particular UV light; (ii) thermal post-curing at a temperature of >100°C to 200°C, in particular over a period of 1 h to 8 h.

[0065] Preferably, the pre-curing takes place via a radical curing mechanism and the post-curing via a non-radical curing mechanism.

[0066] In the radical curing mechanism, radical polymerization of the (meth)acrylate groups and, if applicable, ethylenically unsaturated double bonds occurs. Radical polymerization can be induced thermally or photochemically. Thermal precuring is used particularly in the production of fiber composites, while photochemical precuring is used in stereolithography.

[0067] Without being bound to any theory, it is assumed that the non-radical curing mechanism is a generalized Betti reaction, which can be considered a special case of the Mannich reaction. The Betti reaction is described, for example, in Cardellicchio et al., "The Betti base: the awakening of a sleeping beauty," Tetrahedron: Asymmetry Volume 21, Issue 5, 30 March 2010, Pages 507-517 (see also https: / / en.wikipedia.org / wiki / Betti reaction and https: / / de.wikipedia.org / wiki / Betti-Reaktion). In the present case, it is assumed that the aldehyde (A), the phenolic compound (B), and the amine (C) react via a Betti reaction. This reaction is schematically shown in FIG. 1 shown.

[0068] Particularly preferably, the thermal post-curing (ii) takes place at a temperature of 140 °C to 150 °C.

[0069] The composition according to the invention is preferably a stable, low-viscosity resin that can be processed using common manufacturing processes for fiber composites. Therefore, the process according to the invention is preferably an injection process or an infusion process (e.g., VARI; the vacuum infusion process). These processes are known to those skilled in the art.

[0070] The processes according to the invention can be used to produce thermosets or fiber composite materials with excellent mechanical properties.

[0071] A further object of the invention is therefore a fiber composite material or thermoset obtainable by the process according to the invention.

[0072] The fiber composite materials and thermosets according to the invention are used as components or molded parts (e.g. as pure resin panels, as fiber composite components, etc.) in aircraft construction, rail vehicle construction, automobile construction, shipbuilding, mechanical engineering, plant engineering, construction and in the production of rotor blades for wind turbines.

[0073] Even without further elaboration, it is assumed that a person skilled in the art can utilize the above description to the fullest extent possible. The preferred embodiments and examples are therefore to be considered merely descriptive and not in any way limiting disclosure.

[0074] The subject matter of the present invention is described by FIG. 1 and FIG. 2 explained in more detail, without the subject matter of the present invention being limited thereto.

[0075] FIG. 1shows schematically a condensation reaction (Betti reaction / Mannich reaction) of a phenolic compound (1), an aldehyde (2) and an amine (3) with formation of a Betti base / Mannich base (4) and release of water.

[0076] FIG. 2 shows the results of differential scanning calorimetry (DSC) for the composition according to the invention as described in the examples. Two peaks are visible, one for radical pre-curing and one for non-radical post-curing. Examples General methods: Glass transition temperature / Glass transition temperature (Tg):

[0077] The glass transition temperature (Tg) is determined by dynamic mechanical analysis (DMA) according to ISO 6721-11:2019-06. Elastic modulus (E):

[0078] The elastic modulus (E) is determined by dynamic mechanical analysis (DMA) according to ISO 6721-4:2019-05. Impact resistance:

[0079] Impact strength is determined according to ISO 179-1:2010-11. Viscosity:

[0080] The viscosity is determined according to DIN EN ISO 3219:1994-10. Flexural strength:

[0081] The flexural strength is determined using a three-point bending test according to ISO 178:2019-04. Flexural modulus:

[0082] The flexural modulus is determined using a three-point bending test according to ISO 178:2019-04. Dynamic differential thermal analysis / Differential scanning calorimetry (DSC):

[0083] Dynamic Differential Scanning Analysis (DSC) is carried out according to DIN EN ISO 11357-1:2017-02, DIN EN ISO 11357-2:2020-08 and DIN EN ISO 11357-4:2014-10. Raw materials:

[0084] Designation Manufacturer characterization Visiomer ®< VALMA Evonik Operations GmbH Methacrylated vanillin (vanillin methacrylate) Cardanol NX-2026 Cardolite Cardanol (3-pentadeca-dienyl-phenol) HDDA Allnex Hexanediol diacrylate Aradur ®< 976-1 Huntsman 4,4'-Diaminodiphenylsulfon PEROXAN BP powder 50 W Pergan GmbH Containing powder approx. 40-50% by weight dibenzoyl peroxide approx. 40-50 wt.% Dicyclohexyl phthalate PERGAQUICK A3X Pergan GmbH Solution containing approx. 5-10% by weight of N,N-diethylaniline approx. 80-90% by weight 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate Derakane ®< Momentum 411-200 Ineos (formerly Ashland) Vinyl ester resin based on bisphenol A diglycidyl ether (DGEBA, BADGE) Araldite ®< LY 556 Huntsman Epoxy resin based on bisphenol A diglycidyl ether (DGEBA, BADGE) Albidur ®< HE 600 Evonik Operations GmbH Epoxy resin hardener based on hexahydromethylphthalic anhydride (MHHPA) Ancamine ®< 2167 Evonik Operations GmbH Epoxy resin hardener based on amines ampliTex ®< 5008 Bcomp / Switzerland biaxial flax fiber fabric Resin and fiber composite: a) Production of the resin

[0085] A mixture of 76 parts by weight of Visiomer® VALMA, 10 parts by weight of Cardanol NX-2026, 10 parts by weight of HDDA, and 4 parts by weight of Aradur® 976-1 was first prepared in a speed mixer. This mixture was then annealed for 2 hours at 60 °C. A clear, liquid product with a viscosity of 260 mPas (measured at 25 °C) was obtained. The product was stable in storage. Even after months of storage, the product remained clear and could be easily processed using the infusion process. b) Curing of the resin and mechanical properties

[0086] To 100 parts by weight of product a), 2 parts by weight of Peroxan BP Powder 50W and 0.5 parts by weight of Pergaquick A3X were mixed under inert gas (N 2 ). The pot life (processing time) of this mixture was approximately 4 hours at 60 °C. The mixture was pre-cured for 6 hours at 60 °C and then post-cured for 2 hours at 140 °C. The cured product has a glass transition temperature Tg of approximately 120 °C, a modulus of elasticity of 1.8 GPa, and an impact strength of 1.5 kJ / m 2 . The DSC shows two peaks, one for radical pre-curing and one for non-radical post-curing.

[0087] For comparison, a similarly cured vinyl ester resin typically has a glass transition temperature of approximately 130 °C and a modulus of elasticity of approximately 3 GPa. Vinyl ester resins are also very brittle. A standard epoxy resin such as DGEBA (e.g., Araldite®< LY 556 from Huntsman), cured with an anhydride (e.g., Albidur®< HE 600), has a Tg of 130 °C and a modulus of elasticity of 2.8 GPa. It should be noted that the structure of the cured resin according to the invention is neither similar to that of an epoxy resin nor to that of a vinyl ester resin, particularly because the curing mechanisms differ. Accordingly, different mechanical properties are to be expected. c) Production of a fiber composite material and mechanical properties

[0088] To 100 parts by weight of product a), 2 parts by weight of Peroxan BP Powder 50W and 0.5 parts by weight of Pergaquick A3X were mixed under inert gas (N 2 ). The resulting mixture was then processed using a vacuum infusion process (VARI). Four layers of a biaxial flax fiber fabric with a ±45° structure (ampliTex ®< 5008 from Bcomp / Switzerland) and a basis weight of 350 g / m 2< were used as the fiber material. The resulting fiber-reinforced resin was pre-cured for 4 hours at 60 °C under vacuum and then post-cured for 6 hours at 140 °C in an oven. The mass fraction of renewable raw materials in the resulting fiber composite panel was 93% based on the total mass of the fiber composite material. The fiber composite panel has a glass transition temperature of approximately 120 °C, a flexural strength of 137 MPa and a flexural modulus of 9.8 GPa.

[0089] For comparison: A fiber composite panel made of standard epoxy resin (LY 556 from Huntsman) with an amine (Ancamine®< 2167 from Evonik), cured for 2 h at 80 °C and 4 h at 150 °C, produced under comparable conditions using the same textile fabric (same production batch), exhibits a Tg of 108 °C, a flexural strength of 160 MPa, and a flexural modulus of 9.4 GPa. For a jute-reinforced component based on unsaturated polyester resin, a flexural strength of 80 MPa and a flexural modulus of 4.8 GPa have been reported in the literature.

[0090] Replacement of vanillin methacrylate with an equimolar mixture of vanillin and acrylic acid.

[0091] Analogous to the procedure described under a), a mixture of 52 parts by weight of vanillin, 24 parts by weight of acrylic acid, 10 parts by weight of Cardanol NX-2026, 10 parts by weight of HDDA, and 4 parts by weight of Aradur®< 976-1 was first prepared in a speed mixer, and this composition was then heated for 2 hours at 60 °C. The vanillin did not dissolve completely. A clear solution could therefore not be obtained. Rather, the resulting composition was a suspension. This composition, in turn, was not suitable for use in infusion procedures, as the composition could not flow through the tissue without solid components of the composition being retained by the tissue. After 4 hours of storage at room temperature, some of the undissolved vanillin settled at the bottom of the storage vessel.

[0092] Further attempts were made to cure the resulting mixture according to the procedure described under b). Curing at 60 °C was not observed. At 140 °C, heavy fuming occurred, presumably due to the escaping and possibly decomposing acrylic acid. The final product was a completely unusable, charred, crumbly solid.

Claims

1. Composition comprising - at least one aldehyde (A), - at least one phenolic compound (B) and - at least one amine (C) bearing at least two amino groups selected from the group consisting of primary and secondary amino groups, wherein at least one of these compounds bears at least one (meth)acrylate group.

2. Composition according to Claim 1, characterized in that at least one of the compounds (A), (C) and (B) is produced from renewable raw materials or is a renewable raw material.

3. Composition according to Claim 1 or 2, characterized in that at least one aldehyde (A) bears at least one (meth)acrylate group.

4. Composition according to any of Claims 1 to 3, characterized in that at least one aldehyde (A) is aromatic.

5. Composition according to any of Claims 1 to 4, characterized in that at least one aldehyde (A) is methacrylated vanillin.

6. Composition according to any of Claims 1 to 5, characterized in that at least one phenolic compound (B) is an ethylenically unsaturated compound.

7. Composition according to any of Claims 1 to 6, characterized in that at least one phenolic compound (B) is a cardanol.

8. Composition according to any of Claims 1 to 7, characterized in that at least one amine (C) is aromatic, preferably a dianiline, in particular 4,4'-diaminodiphenylsulfone.

9. Composition according to any of Claims 1 to 8, characterized in that it additionally comprises at least one (meth)acrylate (D), preferably having at least two (meth)acrylate groups, in particular 1,6-hexanediol diacrylate.

10. Composition according to any of Claims 1 to 9, characterized in that it further comprises - at least one initiator (E), preferably benzoyl peroxide, and - optionally at least one accelerator (F), preferably N,N-diethylaniline, and - optionally at least one further additive (G).

11. Composition according to any of Claims 1 to 10, characterized in that it contains or consists of the following constituents in each case based on the total mass of the composition: - one or more aldehydes (A) in a mass fraction of altogether 60% to 90%, preferably 65% to 85%, in particular 70% to 80%; - one or more phenolic compounds (B) in a mass fraction of altogether 1% to 25%, preferably 3% to 20%, in particular 5% to 15%; - one or more amines (C) in a mass fraction of altogether 1% to 20%, preferably of 2% to 10%, in particular of 3% to 5%; - one or more (meth)acrylates (D) in a mass fraction of altogether 1% to 25%, preferably 3% to 20%, in particular 5% to 15%; - one or more initiators (E) in a mass fraction of altogether 0.1% to 5%, preferably of 0.2% to 4%, in particular of 0.3% to 1%; - one or more accelerators (F) in a mass fraction of altogether 0% to 10%, preferably of 0.01% to 5%, in particular of 0.02% to 2%; - one or more additives (G) in a mass fraction of altogether 0% to 10%, preferably of 0.01% to 5%, in particular of 0.02% to 2%.

12. Fibre-reinforced composition comprising - at least one fibre material, preferably composed of one or more renewable raw materials, and - a composition according to any of Claims 1 to 11.

13. Process for curing a composition according to any of Claims 1 to 11 or a fibre-reinforced composition according to Claim 12, characterized in that the curing is effected via a radical and a non-radical curing mechanism and preferably comprises the steps of: (i) a thermal pre-curing at a temperature of 40°C to 100°C, in particular over a period of 1 h to 8 h, and / or a photochemical pre-curing via actinic radiation, in particular UV light; (ii) a thermal post-curing at a temperature of >100°C to 200°C, in particular over a period of 1 h to 8 h.

14. Process according to Claim 13, characterized in that it is an injection process or an infusion process.

15. Fibre composite material / thermoset obtainable by a process according to either of Claims 13 and 14.