Matrix resin for producing fiber composites

Abstract

The invention relates to compositions comprising - at least one aldehyde (A), - at least one phenolic compound (B) and - at least one amine (C) which carries at least two amino groups selected from primary and secondary amino groups, wherein at least one of these compounds carries at least one (meth)acrylate group; to fiber-reinforced compositions comprising these compositions; to methods for curing these compositions; and to fiber composites / thermosets obtainable by these methods.

Description

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

[0002] Glass or carbon fiber reinforced fiber composites used in higher-quality applications are primarily produced based on thermosetting resin systems. Unsaturated polyester resins hold the largest market share, followed by epoxy and vinyl ester resins. Epoxy-based fiber composites generally exhibit the best mechanical properties, while unsaturated polyester-based components exhibit the worst. However, unsaturated polyester resins are cheaper and easier to use than epoxy resins because they are cross-linked with peroxides. Vinyl ester resins offer a trade-off in terms of properties, ease of use, and cost.

[0003] These thermosetting resin systems are all based on oil-based raw materials; polyester resins and vinyl ester resins also contain a relatively large amount of styrene (a substance that is not important in occupational health).

[0004] Therefore, there has long been a search for bio-based matrix resins that are easy to use, possess good mechanical properties, and are cost-effective. However, the resin systems available to date have not met these requirements, see, for example, polyfurfuryl alcohol (PFAL). PFAL crosslinks when water is removed and becomes highly viscous very quickly. Low-viscosity PFAL resins available for potting typically contain a large amount of water. Curing of this resin results in the formation of bubbles. Furthermore, this thermosetting / fiber composite is highly porous.

[0005] Bio-based reactive materials have long been known in the fields of epoxide chemistry (e.g., epoxidized soybean oil or epoxidized cashew nut shell oil) and polyester chemistry (e.g., cashew nut shell oil, rosin resin, or unsaturated oleic acid). These are typically used only as formulation ingredients because, in their pure form, they result in polymers with poor mechanical properties.

[0006] Currently, vanillin is produced industrially on a large scale and at a very cost-effective pace from lignin (a waste product of the paper industry). In 2014, this totaled over 17,000 tons. Vanillin is well known to be used as an aromatizing chemical in the food industry and is therefore non-toxic. Methacrylated vanillin (vanillin methacrylate) is also known. Its production and its uses in composite materials or 3D printing are described, for example, by Stanzione III et al. Vanillin-based resin for use in composite applications", Green Chem., 2012, 14, 2346–2352 Or Bassett et al. "Vanillin-Based Resin for Additive Manufacturing", ACS Sustainable Chem. Eng. 2020, 8, 5626-5635 .

[0007] However, the use of methacrylated vanillin in the field of fiber composites has encountered two problems. First, methacrylated vanillin cannot be simply used in typical fiber composite operations because it is a solid. Although methacrylated vanillin is dissolved in this acrylate monomer, such as 1,6-hexanediol diacrylate (HDDA), which is usually used as a reactive diluent, mixing this solution with the required hardeners and accelerators causes the methacrylated vanillin to recrystallize, making further use impossible. Furthermore, cured methacrylated vanillin is very brittle and therefore unsuitable as a matrix resin for fiber composites.

[0008] The prior art also discloses mixtures of methacrylated vanillin with acrylated and epoxidized soybean oil, such as those from Zhang, C. et al. "Biorenewable Polymers based on acrylated epoxidized soybean oil and methacrylated vanillin", Materials Today Communications 5 (2015) 18–22 The existing technology. However, the mechanical properties of the cured mixture are insufficient for producing fiber composite parts.

[0009] Experiments conducted by the inventors have shown that, as previously mentioned, the mixture of methacrylated vanillin and cashew phenol, which is frequently used in the field of polyester chemistry, is unstable during storage. Methacrylated vanillin also crystallizes out.

[0010] Experiments conducted by the inventors further demonstrate that a mixture of methacrylated vanillin, cashew phenol, and acrylate monomers (e.g., HDDA) as reactive diluents does indeed exhibit better storage stability, but when mixed with hardeners and accelerators, it again leads to spontaneous crystallization, thus making its use impossible.

[0011] Therefore, the problem solved by the present invention is to overcome at least one of the above-mentioned disadvantages.

[0012] It has now been discovered, surprisingly, that this problem is solved by a composition containing...

[0013] - At least one aldehyde (A),

[0014] - At least one phenolic compound (B) and

[0015] - At least one amine (C) having at least two amino groups selected from primary and secondary amino groups,

[0016] At least one of these compounds contains at least one (meth)acrylate group.

[0017] The composition is preferably a resin, also known as a resin system, which can be cured to provide thermosetting materials (so-called thermosetting resin systems), wherein the resin exhibits very favorable properties for the production of composite materials, particularly fiber composites. The resin is storage stable, has low viscosity, and can be readily mixed with commonly used hardeners and accelerators and used further with them. After the addition of hardeners and accelerators, the resin has a sufficiently long pot life (use time) of about 4 hours, which is particularly important in practice. The resin can be pre-cured at moderate temperatures from 40°C to 100°C (e.g., 60°C). After post-curing at temperatures >100°C to 200°C (e.g., 140°C), the resin exhibits very good mechanical properties and is not brittle. Therefore, it is particularly suitable for the production of thermosetting materials and fiber composites.

[0018] Therefore, the present invention first provides a composition comprising

[0019] - At least one aldehyde (A),

[0020] - At least one phenolic compound (B) and

[0021] - At least one amine (C) having at least two amino groups selected from primary and secondary amino groups,

[0022] At least one of these compounds contains at least one (meth)acrylate group.

[0023] The present invention further provides a fiber-reinforced composition comprising

[0024] - At least one fiber material, preferably composed of one or more renewable raw materials, and

[0025] - The composition according to the invention.

[0026] The present invention further provides a method for curing the composition according to the invention or the fiber-reinforced composition according to the invention, characterized in that the curing is carried out via a free radical and non-free radical curing mechanism, and preferably includes the following steps:

[0027] (i) thermal pre-curing at temperatures between 40°C and 100°C, particularly over a period of 1 hour to 8 hours, and / or photochemical pre-curing via photochemical radiation, particularly UV light;

[0028] (ii) Post-curing at temperatures >100°C to 200°C, particularly over a period of 1 to 8 hours.

[0029] The present invention further provides fiber composite materials / thermosetting materials that can be obtained by the method according to the present invention.

[0030] Advantageous configurations of the invention are specified in the dependent claims, embodiments, and description. Furthermore, it is explicitly stated that the disclosure of the subject matter of the invention includes all combinations of the various features described in the present or subsequent description of the invention and claims. More specifically, embodiments of one subject matter of the invention, with necessary modifications, are also applicable to embodiments of other subject matters of the invention.

[0031] The subject matter of the invention and its preferred embodiments are described below by way of example, but it is not intended to limit the invention to these illustrative embodiments. Where scopes, formulas, or compound classes are specified below, these are intended to include not only the respective scopes or groups of compounds explicitly mentioned, but also all subscopes and subgroups of compounds that can be obtained by removing individual values ​​(scopes) or compounds. Where references are made in the context of this specification, their entire contents are intended to form part of the disclosure of this invention.

[0032] Where measurements, parameters, or material properties determined by measurement are reported below, unless otherwise stated, these measurements, parameters, or material properties are measured at 25°C and preferably at standard pressure. Standard pressure should be understood to mean a pressure of 101,325 Pa.

[0033] The expression "(meth)acrylic acid" represents "methacrylic acid" and / or "acrylic acid". Therefore, the term "(meth)acrylate group" represents a methacrylate group and / or an acrylate group. The term "methacrylate group" should be understood to mean a methacrylic acid ester group, and the term "acrylate group" should be understood to mean an acrylic acid ester group.

[0034] As described above, the composition according to the invention comprises

[0035] - At least one aldehyde (A),

[0036] - At least one phenolic compound (B) and

[0037] - At least one amine (C) having at least two amino groups selected from primary and secondary amino groups,

[0038] At least one of these compounds contains at least one (meth)acrylate group.

[0039] (Meth)acrylate groups are essential for free radical curing mechanisms. Aldehydes (A), phenols (B), and amines (C) are also necessary for non-free radical curing mechanisms that do not wish to be bound to a specific theory and proceed via the Betti / Mannich reaction.

[0040] Preferably, at least one of compounds (A), (C), and (B) is produced from renewable raw materials or is made from renewable raw materials. Particularly preferred is when at least one aldehyde (A) and one phenolic compound (B) are produced from renewable raw materials and / or are made from renewable raw materials. Depending on the composition of the mixture, a bio-based raw material mass fraction of, for example, between 75% and 96% based on the total mass of the composition can be achieved.

[0041] Preferably, when at least one or all of the aldehydes (A) have at least one (meth)acrylate group. Also preferably, when at least one or all of the aldehydes (A) are aromatic. Therefore, it is equally preferred when at least one or all of the aldehydes (A) are aromatic and have at least one (meth)acrylate group. Further preferably, when at least one aldehyde (A) is (meth)acrylated vanillin (vanillin (meth)acrylate). Particularly preferred is when only (meth)acrylated vanillin (vanillin (meth)acrylate) is used as the aldehyde (A). In the context of this invention, the terms "(meth)acrylated vanillin" and "vanillin (meth)acrylate" are used synonymously. "(meth)acrylated vanillin" or "vanillin (meth)acrylate" is a (meth)acrylate of 4-(meth)acryloyloxy-3-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde (vanillin). methacrylated vanillin (vanillin methacrylate, 4-methacryloyloxy-3-methoxybenzaldehyde) has a structure according to formula (I):

[0042]

[0043] Formula (I).

[0044] Acrylate-esterified vanillin (vanillin acrylate, 4-acryloyloxy-3-methoxybenzaldehyde) accordingly has the structure shown in formula (II):

[0045]

[0046] Equation (II).

[0047] Particularly preferred is when the at least one aldehyde (A) is or contains methacrylated vanillin (vanillin methacrylate, 4-methacryloyloxy-3-methoxybenzaldehyde). This compound is available, for example, from Evonik under the name Visiomer® VALMA.

[0048] The compositions according to the invention further comprise at least one phenolic compound (B). A phenolic compound should be understood to mean a compound having one or more hydroxyl groups on one or more aromatic systems, also known as aromatic ring systems. Thus, in each case, these hydroxyl groups are bonded to a carbon atom, which is itself part of an aromatic system. The simplest example of a phenolic compound is phenol (hydroxybenzene).

[0049] Preferably, at least one or all of the phenolic compounds (B) are olefinically unsaturated compounds. Olefinically unsaturated compounds should be understood to mean compounds containing at least one C=C double bond that is not part of an aromatic system. Therefore, it is preferred that the phenolic compound (B) contains at least one C=C double bond that is not part of an aromatic system. Without wishing to be bound by a particular theory, it is assumed that the C=C double bond participates at least partially in the radical curing mechanism.

[0050] Particularly preferred is when at least one or all of the phenolic compounds (B) are cashew nut shells. Cashew nut shells are phenolic compounds obtained by the decarboxylation of cashew acid. Cashew acid, in turn, is the main component of cashew nut shell liquid / oil, which in turn is a byproduct of cashew processing. In the context of this invention, cashew acid should be understood to refer to compounds of formula (III) and cashew nut shells to compounds of formula (IV).

[0051]

[0052] Equation (III),

[0053]

[0054] Formula (IV),

[0055] R is either a saturated or unsaturated hydrocarbon group each time it appears.

[0056] Cashew nut shell oil contains cashew acid, and the cashew phenols obtained therefrom typically contain a hydrocarbon group R with 15 carbon atoms, where the degree of saturation can vary. The cashew phenols obtained from cashew nut shell oil contain approximately 41% triunsaturated cashew phenols, approximately 34% monounsaturated cashew phenols, approximately 22% diunsaturated cashew phenols, and approximately 2% saturated cashew phenols, reported in each case as a percentage of mass based on the total mass of cashew phenols.

[0057] Therefore, it is preferred that the group R in formula (III) / (IV) is a hydrocarbon group having 15 carbon atoms. It is even more preferred that the group R in formula (III) / (IV) does not have, has one, two or three C=C double bonds.

[0058] Therefore, it is particularly preferred that the group R in formulas (III) and (IV) is independently a group having 15 carbon atoms each time it appears and has one, two or three C=C double bonds.

[0059] Since C=C double bonds are free radical polymerizable, it is further preferred that group R is a group having at least one C=C double bond each time it appears.

[0060] Therefore, it is preferred that the group R is independently a group having at least one C=C double bond and / or having 15 carbon atoms each time it appears, especially a group having at least one C=C double bond and having 15 carbon atoms.

[0061] Cashew acid contains a group R, such as formula (V), which gives it its name to the cashew acid group and is the main component of cashew acid in cashew shell oil.

[0062]

[0063] Equation (V),

[0064] The dashed lines represent covalent bonds with the benzene ring. Therefore, it is preferred when R in formulas (III) and (IV) is a group of formula (V). Also preferred are groups R that are hydrogenated / saturated derivatives of formula (V) (form) through one, two, or all three C=C double bonds.

[0065] Cashew nut oil is commercially available. Cardanol NX-2026 (Cardolite), a diunsaturated cashew nut oil of formula (VI), wherein R = -C7H, is particularly preferred. 14 -CH=CH-CH2-CH=CH-C3H7.

[0066] Preferably, when R in equations (III) and (IV) is R = -C7H 14 When -CH=CH-CH2-CH=CH-C3H7.

[0067] The composition according to the invention further comprises at least one amine (C) having at least two amino groups selected from primary and secondary amino groups. Primary or secondary amino groups are required for the Mannich / Bette reaction. In contrast, tertiary amino groups cannot react in the Mannich / Bette reaction.

[0068] The composition according to the invention preferably contains at least one amine (C) having at least two primary amino groups.

[0069] Further preferred is when the amine (C) is aromatic. An aromatic amine is an amine containing one or more amino groups, each amino group bonded to a carbon atom, which in turn is part of an aromatic system. The simplest example of an aromatic amine is aniline (aniline, aminobenzene).

[0070] Further preferred is when the amine (C) is dianilin. Dianilin should be understood to mean a compound having two aminophenyl groups, particularly two 4-aminophenyl groups. According to the invention, the amino group is selected from primary and secondary amino groups. Therefore, the amine (C) is particularly preferred to be dianilin having a primary amino group.

[0071] Further preferably, when at least one amine (C) is selected from substituted or unsubstituted 4,4'-isopropylbenzene diphenylamine and substituted or unsubstituted 4,4'-methylenediphenylamine and substituted or unsubstituted 4,4'-sulfonylbenzene diphenylamine, preferably selected from 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2,6-diisopropylaniline) and 4,4'-diaminodiphenyl sulfone. Particularly preferred is when at least one amine (C) is 4,4'-diaminodiphenyl sulfone.

[0072] Diphenylamine is commercially available. Thus, for example, 4,4'-methylenebis(2,6-diethylaniline) is commercially available under the name Lonzacure® M-DEA (Lonza), 4,4'-methylenebis(2,6-diisopropylaniline) is commercially available under the name Lonzacure® M-DIPA (Lonza), and 4,4'-diaminodiphenyl sulfone is commercially available under the name Aradur® 976-1 (Huntsman).

[0073] Preferably, the composition according to the invention further comprises at least one (meth)acrylate (D). (Meth)acrylate should be understood to mean a compound having one or more (meth)acrylate groups, i.e., one or more methacrylate groups and / or acrylate groups. (Meth)acrylate (D) serves as a reactive diluent and / or a crosslinking agent. As a reactive diluent, (meth)acrylate (D) may contain one or more (meth)acrylate groups. As a crosslinking agent, (meth)acrylate (D) must have at least two (meth)acrylate groups. If (meth)acrylate (D) is used both as a reactive diluent and as a crosslinking agent, then (meth)acrylate (D) must therefore contain at least two (meth)acrylate groups. Therefore, it is preferred when at least one or all of the (meth)acrylate (D) has at least two (meth)acrylate groups. More preferably, it is preferred when at least one or all of the (meth)acrylate (D) has two to six (meth)acrylate groups. Preferably, (meth)acrylate (D) is composed only of the elements carbon, hydrogen, oxygen, and nitrogen, particularly only of the elements carbon, hydrogen, and oxygen. Suitable (meth)acrylate (D) is described in European Coatings Tech Files, Patrick Glöckner waiting for "Strahlenhärtung: Beschichtungen und Druckfarben”, 2008, Vincentz Network, Hannover, Germany .

[0074] Preferably, at least one (meth)acrylate (D) is selected from 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.

[0075] Also preferably, when at least one (meth)acrylate (D) is selected from vanillin (4-hydroxy-3-methoxybenzyl alcohol), guaiacol, or (meth)acrylates of methoxycresol, such as those derived from, for example... Holmberg, AL Waiting for someone "Softwood Lignin-Based Methacrylate Polymers with Tunable Thermal and Viscoelastic Properties”, Macromolecules 2016, 49, 1286-1295 As described in [reference needed]. Similar to (meth)acrylated vanillin, these compounds are produced from the renewable raw material lignin.

[0076] Suitable (meth)acrylates (D) can be named Ebecryl® TMPTA (Allnex SA, Germany), Ebecryl® OTA480 (propoxylated glycerol triacrylate, Allnex SA, Germany), Ebecryl® TPGDA (Allnex SA, Germany), Ebecryl® DPGDA (Allnex SA, Germany), Ebecryl® 892 (Allnex SA, Germany), Ebecryl® 11 (polyethylene glycol diacrylate, Allnex SA, Germany), Ebecryl® 45 (Allnex SA, Germany), PETIA (a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate, Allnex SA, Germany), Ebecryl® 150 (bisphenol A-based diacrylate, Allnex SA, Germany), Ebecryl® 605 (A mixture of 80% bisphenol A diepoxy acrylate and 20% TPGDA, Allnex SA, Germany), Ebecryl® 40 (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 (ethoxylated trimethylolpropane triacrylate, Rahn AG, Germany), SR 415 (ethoxylated trimethylolpropane triacrylate, Sartomer, France), SR 489 (tridecyl acrylate, Sartomer, France), and Sarbio® 5101 (dodecyl acrylate, Arkema, France) were commercially available.

[0077] Suitable (meth)acrylates (D) are also commercially available from Evonik Operations GmbH (Germany) under the VISIOMER® product line. Preferred compounds are glycerol formaldehyde methacrylate (VISIOMER® Glyfoma), diurea dimethacrylate (VISIOMER® HEMA TMDI), butyl diethylene glycol 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), methacrylates of fatty alcohols with an average of 13.0 carbon atoms (VISIOMER® Terra C13-MA), or methacrylates of fatty alcohols with an average of 17.4 carbon atoms (VISIOMER® Terra C17.4-MA).

[0078] Particularly preferred is when the composition contains at least one (meth)acrylate (D) selected from difunctional and trifunctional acrylates based on diols and triols, particularly 1,6-hexanediol diacrylate (HDDA).

[0079] Preferably, when the composition according to the invention further comprises at least one initiator (E).

[0080] The initiator (E) in the composition according to the invention is a compound that forms free radicals when exposed to external stimuli. This initiator can be photochemical radiation, preferably UV light and / or visible light, or heat. Therefore, the initiator (E) can be an initiator for photochemical free radical curing / polymerization (photoinitiator) and / or an initiator for thermal free radical curing or polymerization (thermal initiator).

[0081] As a thermal initiator, organic peroxides are preferred, such as 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (e.g., LUPEROX 101®), dilauryl peroxide (e.g., LUPEROX LP®), benzoyl peroxide (e.g., LUPEROX A98®), and bis(tert-butyldioxyisopropyl)benzene (e.g., VulCUP R®) from Arkema (France), or Peroxan BP Pulver 50 W (a powder containing about 40-50% by weight of benzoyl peroxide and about 40-50% by weight of dicyclohexyl phthalate) from Pergan GmbH (Germany). Preferred thermal initiators further include ketone peroxides (such as methyl ethyl ketone peroxide), diacyl peroxides (such as benzoyl peroxide), hydroperoxides (such as cumene hydroperoxide and ketal peroxide), dialkyl peroxides, peroxydicarbonates and peroxy esters, and inorganic peroxides, such as peroxydisulfate, including sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8) and ammonium persulfate ((NH4)2S2O8), and azobisisobutyronitrile (AIBN).

[0082] Suitable photoinitiators include all photoinitiators known to those skilled in the art, including Norrish type I and Norrish type II photoinitiators. This includes commonly used UV photoinitiators such as acetophenone (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). Particularly preferred are Norrish type I photoinitiators, such as benzophenone, benzoin, α-hydroxyalkyl phenyl ketone, acylphosphine oxide, or derivatives thereof. Suitable photoinitiators are described in, for example, "A Compilation of Photoinitiators Commercially available for UV today” (K. Dietliker, SITA Technology Ltd., London 2002) middle.

[0083] Preferably, when the composition according to the invention further comprises at least one accelerator (F).

[0084] When the composition contains a thermal initiator, it is preferable to have an accelerator (F) that accelerates such free radical thermosetting. 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-dimethyl-p-toluidine.

[0085] When the composition contains a photoinitiator, it is preferable that an accelerator (F) promoting such photochemical radical curing is present. Such accelerators are also known as photosensitizers. 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-aminobenzyl nitrile; and phosphorus compounds such as sodium diethylthiophosphate.

[0086] Particularly preferred is when the composition according to the invention contains at least one tertiary amine, preferably at least one aromatic tertiary amine, particularly N,N-diethylaniline as a promoter (F). N,N-diethylaniline is commercially available, for example, under the name PERGAQUICKA3X from Pergan GmbH (Germany) in solution. This solution contains about 5-10% by weight of N,N-diethylaniline and about 80-90% by weight of 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate.

[0087] Preferably, the composition according to the invention further comprises at least one other additive (G). The additive (G) is preferably a substance that can be used to specifically modulate the properties of the uncured or cured composition. These can be, for example, dyes, pigments, rheology modifiers, and impact modifiers, but can also be nanoscale fillers available using potting and injection processes. Examples include acrylate-functionalized acrylonitrile-butadiene copolymers, such as Hypro® VTBNX 1300x43 from Huntsman, Tegomer® M-Si 2650 from Evonik Operations, nano-silica, and nano-aluminates.

[0088] Preferably, the composition according to the invention comprises or consists of the following components based on the total mass of the composition in each case:

[0089] - One or more aldehydes (A), having a total mass fraction of 60% to 90%, preferably 65% ​​to 85%, particularly 70% to 80%;

[0090] - One or more phenolic compounds (B), wherein the total mass fraction is 1% to 25%, preferably 3% to 20%, particularly 5% to 15%;

[0091] - One or more amines (C), wherein the total mass fraction is 1% to 20%, preferably 2% to 10%, particularly 3% to 5%;

[0092] - One or more (meth)acrylates (D), wherein the total mass fraction is 1% to 25%, preferably 3% to 20%, particularly 5% to 15%;

[0093] - One or more initiators (E) having a total mass fraction of 0.1% to 5%, preferably 0.2% to 4%, particularly 0.3% to 1%;

[0094] - One or more accelerators (F) having a total mass fraction of 0% to 10%, preferably 0.01% to 5%, particularly 0.02% to 2%;

[0095] - One or more additives (G) having a total mass fraction of 0% to 10%, preferably 0.01% to 5%, particularly 0.02% to 2%.

[0096] The mandatory / optional components of the compositions according to the invention, namely the aldehyde (A), phenolic compound (B), amine (C), (meth)acrylate (D), initiator (E), accelerator (F), and additive (G), are all distinct from each other. If a compound can in principle be assigned to two or more of the aforementioned groups (A), (B), (C), (D), (E), (F), and (G), then the compound shall be assigned to the first mentioned group among those possible groups in the above sequence, unless explicitly deviating from this rule. For example, if a compound can be assigned to any of groups (B), (D), and (G), then it should be assigned to the first of the possible groups, i.e., (B) in this example. Therefore, a compound is not assigned to more than one of groups (A), (B), (C), (D), (E), (F), and (G).

[0097] The compositions according to the invention can be used as encapsulating compounds in electronic devices or in stereolithography (SLA). However, the compositions according to the invention are particularly suitable for producing fiber-reinforced compositions, and consequently for producing fiber composite materials thereof.

[0098] Therefore, the present invention further provides a fiber-reinforced composition comprising

[0099] - At least one fiber material, preferably composed of one or more renewable raw materials, and

[0100] - The composition according to the invention.

[0101] The fiber material is preferably a monofilament, a fiber bundle containing a monofilament, or a yarn containing a monofilament or fiber bundle. The fiber material is further preferably a product, such as a non-crimped fabric or woven fabric containing a monofilament, fiber bundle, or yarn. Non-crimped fabrics containing fiber bundles are particularly preferred. In the case of woven fabrics, these fabrics are preferably plain-weave. Preferred non-crimped fabrics are constructed in layers, which can be oriented in the same direction (for uniaxial construction) or in different directions (for multiaxial construction). The advantage of non-crimped fabrics is that the fibers or fiber bundles in the layers do not bend during the weaving operation. This results in higher force absorption capacity. The fiber material is preferably glass fiber, mineral fiber, natural fiber, and / or polymer fiber material, more preferably natural fiber material, especially natural fiber. The fiber material is more preferably a non-crimped fabric composed of glass fiber, mineral fiber, natural fiber, and / or polymer fiber material, especially a non-crimped fabric composed of natural fiber. The fiber material is preferably a primary product of manufacture, used as a cleaning material or a coated material; clean fiber materials are preferred. Cleaning is preferably material-dependent, and the preferred cleaning process is heat treatment, particularly radiation using an IR emitter. Heat treatment can optionally be performed under a protective gas atmosphere. This cleaning step, in particular, removes water, which is almost always present in natural fibers and is detrimental in their subsequent use, to provide fiber composites. Preferably, this is done when the fiber material is selected from flax, hemp, jute, kenaf, ramie, sisal, and wood fibers. Ultrasonic digestion can specifically modify the fibers, allowing standardized processing operations to impart repeatable technical properties.

[0102] The compositions according to the invention and the fiber-reinforced compositions according to the invention can be cured using specific methods. The curing of these compositions occurs via both free radical curing mechanisms and non-free radical curing mechanisms.

[0103] Therefore, the present invention further provides a method for curing the composition according to the invention or the fiber-reinforced composition according to the invention, characterized in that the curing is carried out via a free radical and non-free radical curing mechanism, and preferably includes the following steps:

[0104] (i) thermal pre-curing at temperatures between 40°C and 100°C, particularly over a period of 1 hour to 8 hours, and / or photochemical pre-curing via photochemical radiation, particularly UV light;

[0105] (ii) Post-curing at temperatures >100°C to 200°C, particularly over a period of 1 to 8 hours.

[0106] Pre-curing is preferably achieved via a free radical curing mechanism, while post-curing is achieved via a non-free radical curing mechanism.

[0107] The free radical curing mechanism influences the free radical polymerization of (meth)acrylate groups and optionally present olefinic unsaturated double bonds. Free radical polymerization can be thermally induced or photochemically induced. Thermal pre-curing is particularly used in the production of fiber composites, while photochemical pre-curing is used in stereolithography for the production of fiber composites.

[0108] Without being bound by a specific theory, the non-radical solidification mechanism is considered a generalized Betty reaction, which can be viewed as a special case of the Mannich reaction. The Betty reaction is described, for example... Cardellicchio waiting for " 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 this application, it is assumed that an aldehyde (A), a phenolic compound (B), and an amine (C) react with each other via the Betti reaction. This reaction is schematically shown... Figure 1 middle.

[0109] Particularly preferred is when post-curing with heat is performed at a temperature of 140°C to 150°C (ii).

[0110] The compositions according to the invention are preferably stable, low-viscosity resins that can be used in common production methods for fiber composites. Therefore, the methods according to the invention are preferably injection or infusion processes (e.g., VARI; vacuum infusion process). These methods are known to those skilled in the art.

[0111] The method according to the present invention enables the production of thermosetting / fiber composite materials with excellent mechanical properties.

[0112] Therefore, the present invention further provides fiber composite materials / thermosetting materials that can be obtained by the method according to the present invention.

[0113] The fiber composite materials and thermosetting materials according to the present invention are used in aircraft structures, rail vehicle structures, automobile manufacturing, shipbuilding, machine structures, equipment structures, building structures, and as components / molded parts in the production of rotor blades for wind power generation equipment (e.g., as pure resin sheets, as fiber composite components, etc.).

[0114] Even without further elaboration, it is assumed that those skilled in the art will be able to utilize the foregoing description to the fullest extent possible. Therefore, the preferred embodiments and examples are to be interpreted as descriptive disclosures only and are in no way intended to be limiting.

[0115] The subject matter of this invention will be referred to Figure 1 and Figure 2 The invention will be described in more detail, but is not intended to limit the subject matter thereto.

[0116] Figure 1 This is a schematic diagram of the condensation reaction (Betti reaction / Mannich reaction) of phenolic compound (1), aldehyde (2) and amine (3) to form Betti base / Mannich base (4) and release water.

[0117] Figure 2 The results of differential scanning calorimetry (DSC) for the compositions according to the invention as described in the examples are shown. Two peaks are evident, one for free radical pre-curing and the other for non-free radical post-curing.

[0118] Example

[0119] General method:

[0120] Glass transition temperature (Tg):

[0121] The glass transition temperature (Tg) was determined by dynamic mechanical analysis (DMA) according to standard ISO 6721-11:2019-06.

[0122] Elastic modulus (E):

[0123] According to standard ISO 6721-4:2019-05, the modulus of elasticity (E) is determined by dynamic mechanical analysis (DMA).

[0124] Impact strength:

[0125] The impact strength is determined according to standard ISO 179-1:2010-11.

[0126] Viscosity:

[0127] Viscosity was determined according to standard DIN EN ISO 3219:1994-10.

[0128] Bending strength:

[0129] Bending strength is determined by a three-point bending test according to standard ISO 178:2019-04.

[0130] Flexural modulus:

[0131] The flexural modulus is determined by a three-point bending test according to standard ISO 178:2019-04.

[0132] Differential scanning calorimetry (DSC):

[0133] Differential scanning calorimetry was performed according to DIN EN ISO 11357-1:2017-02, DIN EN ISO 11357-2:2020-08 and DIN EN ISO11357-4:2014-10.

[0134] Raw materials:

[0135]

[0136] Resin and fiber composite materials:

[0137] a) Resin production

[0138] In the Speedmixer, an initial 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 prepared, followed by heat treatment at 60°C for 2 hours. A clear liquid product with a viscosity of 260 mPas (measured at 25°C) was obtained. This product is stable during storage. Even after several months of storage, the product remains transparent and can be readily used further during the filling process.

[0139] b) Curing and mechanical properties of the resin

[0140] 100 parts by weight of product a) were mixed with 2 parts by weight of Peroxan BP Pulver 50W and 0.5 parts by weight of Pergaquick A3X under an inert gas (N2) atmosphere. The pot life (use time) of this mixture at 60°C was approximately 4 hours. The mixture was pre-cured at 60°C for 6 hours, followed by post-curing at 140°C for 2 hours. The cured product had a glass transition temperature (Tg) of approximately 120°C, an elastic modulus of 1.8 GPa, and an impact strength of 1.5 kJ / m². DSC analysis showed two peaks, one for free radical pre-curing and the other for non-free radical post-curing.

[0141] For comparison: similarly cured vinyl ester resins typically have a glass transition temperature of about 130°C and an elastic modulus of about 3 GPa. Vinyl ester resins are also brittle. Standard epoxy resins cured with acid anhydrides (e.g., Albidur® HE 600), such as DGEBA (e.g., Araldite® LY 556 from Huntsman), have a Tg of 130°C and an elastic modulus of 2.8 GPa. It must be noted here that the structure of the cured resin of the present invention is neither the same as that of epoxy resins nor that of vinyl ester resins, especially because of the different curing mechanisms. Therefore, different mechanical properties can also be expected.

[0142] c) Production and mechanical properties of fiber composite materials

[0143] 100 parts by weight of product a) were mixed with 2 parts by weight of Peroxan BP Pulver 50W and 0.5 parts by weight of Pergaquick A3X under an inert gas (N2) atmosphere. The resulting mixture was then used using a vacuum infusion method (VARI). The fibrous material used was a 4-layer biaxial flax non-crimp fabric with a ±45° construction (ampliTex® 5008 from Bcomp / Switzerland) and 350 g / m². 2 The basis weight was determined. The obtained fiber-reinforced resin was pre-cured under vacuum at 60°C for 4 hours, followed by post-curing in an oven at 140°C for 6 hours. The mass fraction of renewable raw materials in the resulting fiber composite sheet was 93% based on the total mass of the fiber composite material. The fiber composite sheet has a glass transition temperature of approximately 120°C, a flexural strength of 137 MPa, and a flexural modulus of 9.8 GPa.

[0144] For comparison: the fiber composite sheet, with a Tg of 108°C, a flexural strength of 160 MPa, and a flexural modulus of 9.4 GPa, was produced under comparable conditions using the same textile non-crimped fabric (same production batch) with standard epoxy resin (LY 556 from Huntsman) and amine (Ancamine® 2167 from Evonik) and cured at 80°C for 2 hours and at 150°C for 4 hours. For jute-reinforced parts based on unsaturated polyester resin, the literature reports a flexural strength of 80 MPa and a flexural modulus of 4.8 GPa.

[0145] Replace vanillin methacrylate with an equimolar mixture of vanillin and acrylic acid.

[0146] Similar to the method described in 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 initially produced using a Speedmixer, followed by heat treatment of the composition at 60°C for 2 hours. The vanillin was only partially dissolved. Therefore, a clear solution could not be obtained. Instead, the resulting composition was a suspension. This composition was unsuitable for use in the filling process because it could not flow through the fabric without the solid components being blocked by the fabric. Furthermore, after storage at room temperature for 4 hours, some of the undissolved vanillin precipitated at the bottom of the storage container. Further attempts were made to cure the obtained mixture according to the method described in b). No curing was observed at 60°C. Severe fumes were observed at 140°C, clearly due to the escape and possible decomposition of the acrylic acid. Finally, a completely unusable, charred, and brittle solid was obtained.

Claims

1. A composition comprising, based on the total mass of the composition, - Methacrylated vanillin (A) with a total mass fraction of 60% to 90%, - At least one phenolic compound (B) comprising a total mass fraction of 1% to 25%, wherein the at least one phenolic compound (B) is an olefinically unsaturated compound. - At least one amine (C) comprising a total mass fraction of 1% to 20%, having at least two amino groups selected from primary and secondary amino groups, wherein the at least one amine (C) is aromatic, and - At least one (meth)acrylate (D) in a total mass fraction of 1% to 25%, At least one of these compounds contains at least one (meth)acrylate group.

2. The composition according to claim 1, characterized in that, At least one of the compounds (A), (C) and (B) is produced from or is made from renewable raw materials.

3. The composition according to claim 1, characterized in that, At least one phenolic compound (B) is cashew nut alcohol.

4. The composition according to claim 1, characterized in that, At least one amine (C) is a compound containing two aminophenyl groups.

5. The composition according to claim 1, characterized in that, At least one amine (C) is 4,4'-diaminodiphenyl sulfone.

6. The composition according to claim 1, characterized in that, The at least one (meth)acrylate (D) has at least two (meth)acrylate groups.

7. The composition according to claim 1, characterized in that, The at least one (meth)acrylate (D) is 1,6-hexanediol diacrylate.

8. The composition according to claim 1, characterized in that, The composition further comprises - At least one initiator (E), and - At least one accelerator (F) may be present, and - At least one additional additive (G) may be present.

9. The composition according to claim 8, characterized in that, - The at least one initiator (E) is benzoyl peroxide, and - The at least one accelerator (F) is N,N-diethylaniline.

10. The composition according to claim 8, characterized in that, In each case, based on the total mass of the composition, the composition comprises or consists of the following components: - Methacrylated vanillin (A) with a total mass fraction of 65% to 85%; - One or more phenolic compounds (B) with a total mass fraction of 3% to 20%; - One or more amines (C) with a total mass fraction of 2% to 10%; - One or more (meth)acrylates (D) in a total mass fraction of 3% to 20%; - One or more initiators (E) with a total mass fraction of 0.1% to 5%; - One or more accelerators (F) with a total mass fraction of 0% to 10%; - One or more additives (G) with a total mass fraction of 0% to 10%.

11. The composition according to claim 10, characterized in that, In each case, based on the total mass of the composition, the composition comprises or consists of the following components: - Methacrylated vanillin (A) with a total mass fraction of 70% to 80%; - One or more phenolic compounds (B) with a total mass fraction of 5% to 15%; - One or more amines (C) with a total mass fraction of 3% to 5%; - One or more (meth)acrylates (D) with a total mass fraction of 5% to 15%; - One or more initiators (E) with a total mass fraction of 0.2% to 4%; - One or more accelerators (F) with a total mass fraction of 0.01% to 5%; - One or more additives (G) with a total mass fraction of 0.01% to 5%.

12. The composition according to claim 11, characterized in that, In each case, based on the total mass of the composition, the composition comprises the following components: - One or more initiators (E) with a total mass fraction of 0.3% to 1%; - One or more accelerators (F) with a total mass fraction of 0.02% to 2%; - One or more additives (G) with a total mass fraction of 0.02% to 2%.

13. A fiber-reinforced composition comprising - At least one fibrous material, and - The composition according to any one of claims 1 to 12.

14. The fiber-reinforced composition according to claim 13, wherein... The at least one fiber material is composed of one or more renewable raw materials.

15. A method for curing the composition according to any one of claims 1 to 12 or the fiber-reinforced composition according to claim 13 or 14, characterized in that, The curing is carried out via a free radical and non-free radical curing mechanism and includes the following steps: (i) thermal pre-curing at temperatures between 40°C and 100°C, and / or photochemical pre-curing via photochemical radiation; (ii) Post-curing at temperatures >100°C to 200°C.

16. The method of claim 15, wherein (i) The heat pre-curing step at a temperature of 40°C to 100°C takes 1 hour to 8 hours; (ii) A post-curing heat treatment at a temperature of >100°C to 200°C for 1 to 8 hours.

17. The method of claim 15, wherein the photochemical precuring is a photochemical precuring using UV light.

18. The method according to claim 15, characterized in that, The method is an injection method or an infusion method.

19. A fiber composite / thermosetting material that can be obtained by the method according to any one of claims 15 to 18.

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