Urea derivatives and their use as hardeners and hardener accelerators for resin systems - Patents.com

Abstract

Bis-orthohydroxy aromatic urones and their use as curing agents and cure accelerators in resin systems, particularly epoxy resin systems, provide formulations with good longevity, low cure temperatures, and desirable glass transition temperatures after cure, and are particularly useful in prepregs used in the manufacture of parts for the aerospace and wind turbine industries.

Description

[Technical Field]

[0001] The present invention relates to novel derivatives of urea, their use as curing agents or curing accelerators for resin systems, especially epoxy resins, epoxy resin formulations containing the urea derivatives, and prepregs and molded articles using such epoxy resin formulations. Thus, the present invention provides novel urea-based compounds, curing agent systems, resin formulations, cured resins, uses, composites, and molding materials. [Background technology]

[0002] Adipic dihydrazide and isophthalic dihydrazide are known as curing agents for epoxy resin formulations. As disclosed in U.S. Patents 4,404,356 and 4,507,445, it has been suggested that they can be used with accelerators such as urea-based materials. However, there remains a need for curing agents that combine shelf stability of the resin formulation prior to curing, low-temperature cure to produce a cured resin with a high glass transition temperature (Tg), and rapid cure, and further retain such Tg for a period of time, especially when exposed to moisture at elevated temperatures. Accordingly, one object of the present invention is to provide a curable epoxy resin composition that has enhanced cure properties, including excellent shelf stability, low temperature cure, and faster cure, and provides a cured product with excellent mechanical properties.

[0003] A hardener is a compound suitable for initiating or promoting the polymerization reaction of a polymerizable resin. An accelerator is a compound that promotes the polymerization reaction (or "cure") caused by the hardener.

[0004] Curing epoxy resins is typically an exothermic reaction, and controlling the reaction to avoid excessive temperatures that can degrade the epoxy material and cause stresses and distortions, such as cracking, in articles and parts made from epoxy-containing formulations is crucial. However, there is a continuing need to increase the Tg of cured epoxy resins to provide sufficient strength to articles and parts, especially when fibers are used in resin-impregnated fiber reinforcements, sometimes known as prepregs. These prepregs are used to produce increasingly larger articles, particularly those with increasing thickness formed from stacks of prepregs, such as stacks of more than 40 prepregs, and sometimes even more than 60 and even 80 prepregs, particularly in the production of parts for the aerospace and wind turbine industries. Prepregs contain fiber reinforcements impregnated with a curable resin that is immediately cured in a mold or vacuum bag. To date, higher Tg has been achieved by using higher cure temperatures and / or longer cure cycles, as well as by employing curing agents such as dicyandiamide, which require higher cure temperatures. However, this increases the risk of resin degradation at high temperatures.

[0005] It has been proposed that the use of urone as a curing agent allows for the use of lower cure temperatures and shorter cure cycles to obtain higher Tg's.

[0006] Derivatives of urea are known to have use as curing agents for epoxy resins, and such derivatives are sometimes known as urones. U.S. Patent No. 4,404,356 relates to hydroxyphenylureas of the following formula and their use as accelerators for the thermal cure of epoxy resins, and as primary curing agents for epoxy resins: [ka]

[0007] US Patent No. 9,663,609 relates to the use of di- or polyfunctional N,N'-(dimethyl)urones and methods for curing epoxy resin compositions using such urones. The use of these materials is said to provide a method for controlled curing of epoxy resins, particularly for solid parts having a large layer thickness of epoxy resin to avoid internal stress or other thermal damage in moldings or parts made from epoxy resins. The di- or polyfunctional N,N'-(dimethyl)urones have the general formula: R-(NH-CO-N(CH3)2) n where R is a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20. Summary of the Invention [Problem to be solved by the invention]

[0008] However, U.S. Patent No. 9,663,609 does not contemplate that when R is an aromatic group, it may be hydroxy-substituted. The use of di- or polyfunctional orthohydroxy aromatic urones according to the present invention as curing agents or curing accelerators further improves the control of the cure of epoxy resins, particularly in prepregs. [Means for solving the problem]

[0009] Here, we have prepared difunctional orthohydroxy aromatic urones and have found that when used as curing agents for epoxy resins, curing the resins at lower temperatures, such as external application temperatures of 80°C to 150°C, can produce cured epoxy resins with higher Tg when fully cured. Such cured epoxy resins have higher Tg than cured epoxy resins made from non-hydroxy-substituted aromatic difunctional urones, such as those described in U.S. Pat. No. 9,663,609, and hydroxylphenyl ureas, such as those described in U.S. Pat. No. 4,404,356. The urones of the present invention can also be used as accelerators for other epoxy curing agents when the curing temperature can be higher, for example, up to 180°C.

[0010] Thus, in one embodiment, the present invention provides di- and polyfunctional orthohydroxy aromatic urones, their use as curing agents for epoxy resins, their use as accelerators for other curing agents for epoxy resins, epoxy resin formulations comprising di- and polyfunctional orthohydroxy urones, and the use of such formulations as resin matrices for reinforcing fibers, particularly in prepregs and fiber-reinforced materials made therefrom.

[0011] Thus, the present invention provides di- and polyfunctional orthohydroxy aromatic urons of formula selected from the following: [ka] During the ceremony, R1 is S, SO2, SO, P, PX, N, NH, NX, P=O (OX or OH), C=O, a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20. X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group. R2 and R3 are, in each case independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms (preferably chlorine atoms) or by hydroxyl or cyano groups, with the proviso that R may alternatively represent a hydrogen atom, or R2 and R3 together with the indicated bonding nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and, optionally, one oxygen atom. R4, in each occurrence, independently of one another, is selected from H, NH2, NO2, nitrile, halogen, a straight-chain or branched-chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group; and Y is 1 to 3. [Brief explanation of the drawings]

[0012] [Figure 1] The graph in Figure 1 demonstrates that in Example 5, the lifetime performance is similar to that of both the standard difunctional uron and the monofunctional OHFU. [Figure 2] The graph in Figure 2 demonstrates that in Example 6, the life performance for the product of the invention is similar to that of the standard difunctional uron and slightly better than the monofunctional OHFU. [Figure 3] FIG. 3, a graph, demonstrates that in Example 6, the PBOHFU of the present invention exhibits better latency performance at 80° C. than the monofunctional OHFU and approaches that of the standard bifunctional urons UR500 and U52. [Figure 4] The graph in Figure 4 demonstrates that in Example 7, the FBOHFU and PBOHFU of the present invention exhibit consistent latency performance at 100°C at both 1% and 0.50% loadings compared to formulations without an accelerator. DETAILED DESCRIPTION OF THE INVENTION

[0013] The compounds of the present invention can be used as curing agents or accelerators for other curing agents, or can perform both of these functions, particularly with epoxy resins, and the present invention also provides epoxy resin formulations comprising one or more of the compounds of the present invention, optionally together with one or more other curing agents.

[0014] When the urea derivative of the present invention is used as the primary or sole curing agent for a resin, it is preferred to use 2 to 20% by weight, more preferably 5 to 15% by weight, of the urea derivative based on the weight of the resin.

[0015] The use of the urea derivatives of the present invention as the primary or sole curing agent in a thermosetting resin system results in a material that can be stored for several weeks (known as the system's shelf life) without significant curing and that produces a cured resin with a desirable Tg for applications such as prepregs used to make parts for the aerospace and wind energy industries, especially when each part is thick and formed from a stack of multiple layers of prepreg. Such stacks typically contain at least 40 layers, and in some cases 60 layers or more. The use of a curing agent also allows for improved control of the heat generated during the curing reaction, avoiding the risk of a runaway reaction that could cause resin degradation and damage to the cured article.

[0016] The compounds of the present invention can also be used as accelerators for other curing agents for epoxy resins. Examples of curing agents whose performance can be enhanced by the compounds of the present invention include primary or secondary amines. These amines may be aliphatic, alicyclic, aromatic, or aromatic structures with one or more amino moieties.

[0017] Examples of amine curing agents include ethylenediamine, diethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, tetraethylenepentamine, hexaethyleneheptamine, hexamethylenediamine, cyanoguanidine, 2-methyl-1,5-pentamethylenediamine, 4,7,10-trioxatridecane-1,13-diamine, aminoethylpiperazine, etc. Exemplary curing agents include dicyanopolyamides, most preferably (DICY), 4,4'-diaminodiphenylsulfone (4,4'-DDS), or 3,3'-diaminodiphenylsulfone (3,3'-DDS). These are advantageously used as latent amine curing agents, and mixtures of DICY and DDS are also suitable. Dihydrazides (eg, ADH, IDH), polyamines (eg, Ancamine 2441), and BF3-MEA complexes (eg, Anchor 1040 (manufactured by Air Products)) are also suitable as latent curing agents.

[0018] In some embodiments, the amine curing agent is a polyetheramine having one or more amine moieties, including polyetheramines that can be derived from polypropylene oxide or polyethylene oxide. Commercially available polyetheramines include polyetherpolyamine (available from Huntsman Corporation under the trade name "JEFFAMINE") and 4,7,10-trioxatridencane-1,13-diamine (TTD) (available from BASF). A preferred latent amine curing agent is Dyhard 100E from AlzChem.

[0019] Other preferred curing agents are aminosulfones, such as 4,4-diaminodiphenyl sulfone (sometimes known as 4,4-DDS) and 3,3-diaminodiphenyl sulfone (sometimes known as 3,3-DDS), which are typically used as curing agents in resin formulations used in the manufacture of aerospace parts.

[0020] When the compounds of the present invention are used as accelerators for other curing agents, they can be used in lower amounts, based on the weight of the epoxy resin, than when the compounds are the primary or sole curing agent. For this application, it is preferred to use 0.1 to 1.5 wt. %, more preferably 0.2 to 1 wt. %, based on the weight of the epoxy resin.

[0021] In a further embodiment of the present invention, there is provided a resin formulation comprising a bis(orthohydroxy)aromatic urone in combination with at least one resin component such as an epoxy, polyisocyanate, and phenolic resin, especially an epoxy resin. The resin formulation is preferably in the form of a one-component resin formulation, which does not require further mixing of the components prior to use.

[0022] In a further embodiment, there are provided resin formulations comprising curable resins such as epoxy, polyisocyanate and phenolic resins containing a curing agent other than a bis-orthohydroxy aromatic urone of the present invention together with a bis-orthohydroxy aromatic urone of the present invention which acts as an accelerator for the curing agent.

[0023] In a further embodiment, the present invention provides the use of the resin formulation of the present invention as a matrix in a fiber reinforced composite material, which may be a prepreg or may be obtained by resin infusion of dry fiber material laid up in a mold with the resin formulation. The present invention further provides a fiber reinforced composite material obtained by heat curing of such a resin matrix, which heat curing may be carried out in a press or in a vacuum bag.

[0024] The cure Tg of the resin is measured according to ASTM D7028 ("Glass Transition Temperature (DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA)").

[0025] The heat released during the curing reaction is related to the total heat required for complete cure and can be measured using a digital scanning calorimeter as follows: A reference resin sample is heated from 10°C to 350°C at a rate of 10°C / min until it is fully cured (100%), and the heat generated, ΔHi, is recorded. A specific resin sample with the same composition as the reference resin sample can then be cured by heating the sample under these conditions to a desired temperature, at a desired rate, and for a desired time, and the heat generated in the curing reaction, ΔHe, can be measured to determine the degree of cure of that specific resin sample. This degree of cure (% cure) is defined as follows: Curing % = [(ΔHi-ΔHe) / ΔHi]×100[%] where ΔHi is the heat generated by uncured resin heated from 10°C to 350°C until fully cured, and ΔHe is the heat generated by a resin cured to a particular degree being heated at a desired rate to the desired temperature.

[0026] In another embodiment of the present invention, a molding material is provided that includes the thermosetting resin formulation of the present invention in combination with a fiber reinforcement material. The fiber reinforcement material may be provided as a woven or multiaxial fabric to form a prepreg, as individual fiber tows to be impregnated with a resin composition to form a towpreg, or as chopped fibers, staple fibers, or filaments to form a molding compound. Preferred fiber materials are selected from carbon fiber, glass fiber, aramid, and mixtures thereof. The molding material may be composed of a cast resin film containing the resin formulation and combined with a fiber reinforcement layer. Impregnation of the resin film into the fiber reinforcement is preferred, which can be achieved by pressing a layer of resin onto the fiber material or by injecting the resin into the fiber material in a mold.

[0027] In a further embodiment of the present invention, there is provided an adhesive comprising the resin formulation of the present invention in combination with at least one filler.

[0028] The compositions of the present invention are shelf stable at ambient temperatures before cure and can be rapidly cured at relatively low temperatures, such as 80°C to 150°C, while the Tg, retained Tg, and mechanical properties of the cured resin enable the use of the cured resin formulation as a fiber reinforced material useful in industrial structural applications, particularly automotive and aerospace structural components as well as sporting goods and wind turbine components.

[0029] When the resin is an epoxy resin, it may be monofunctional or polyfunctional, preferably at least difunctional. In one embodiment, the epoxy resin component (A) may be selected from a variety of polyepoxy compounds known in the art.Examples thereof include aromatic glycidyl ether compounds, such as bis(4-hydroxyphenyl)propane diglycidyl ether, bis(4-hydroxy-3,5-dibromophenyl)propane diglycidyl ether, bis(4-hydroxyphenyl)ethane diglycidyl ether, bis(4-hydroxyphenyl)methane diglycidyl ether, resorcinol diglycidyl ether, phloroglucinol triglycidyl ether, trihydroxybiphenyl triglycidyl ether, and tetraglycidyl benzophenone. , bisresorcinol tetraglycidyl ether, tetramethyl bisphenol A diglycidyl ether, bisphenol C diglycidyl ether, bisphenol hexafluoropropane diglycidyl ether, 1,3-bis[1-(2,3-epoxypropoxy)-1-trifluoromethyl-2,2,2-trifluoroethyl]benzene, 1,4-bis[1-(2,3-epoxypropoxy)-1-trifluoromethyl-2,2,2-trifluoromethyl]benzene, 4,4'-bis(2,3-epoxypropoxy) ) octafluorobiphenyl, and phenol novolac type bisepoxy compounds; alicyclic polyepoxy compounds, such as alicyclic diepoxy acetals, alicyclic diepoxy adipates, alicyclic diepoxy carboxylates, and vinylcyclohexene dioxide; glycidyl ester compounds, such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, dimethylglycidyl phthalate, dimethylglycidyl hexahydrophthalate, diglycidyl p-oxybenzoate, diglycidyl glycidyl cyclopentane-1,3-dicarboxylate, and dimer acid glycidyl ester; glycidyl amine compounds such as diglycidyl aniline, diglycidyl toluidine, triglycidyl aminophenol, tetraglycidyl diaminodiphenylmethane, and diglycidyl tribromoaniline; heterocyclic epoxy compounds such as diglycidyl hydantoin, glycidyl glycidoxyalkylhydantoin, and triglycidyl isocyanurate; and oligomeric compounds thereof.

[0030] Examples of liquid epoxy resins include polyalkylene ether-type epoxy compounds, such as (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether; glycidyl ester-type epoxy compounds, such as dimer acid diglycidyl ester, phthalic acid diglycidyl ester, and tetrahydrophthalic acid diglycidyl ester; and homopolymers of glycidyl (meth)acrylate, allyl glycidyl ether, etc., or copolymers of these monomers with other soft unsaturated monomers. Here, "soft unsaturated monomers" refers to monomers including homopolymers with a glass transition temperature of less than 60°C. Examples of soft unsaturated monomers include methyl acrylate, ethyl acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl methacrylate.

[0031] The curable liquid epoxy resin composition of the present invention is particularly useful as a one-component liquid epoxy resin prepreg matrix resin formulation that provides a cured product having both excellent storage stability and curing properties, and excellent properties, particularly organic solvent resistance.

[0032] When the epoxy resin composition of the present invention is used as a prepreg resin formulation, known additives such as fillers, viscosity modifiers, toughening agents, pigments, thixotropic agents, and flame retardants can optionally be mixed into the formulation to enhance its mechanical performance and flow behavior during curing.

[0033] The compositions of the present invention may contain other typical additives used in thermosetting resin formulations such as impact modifiers, fillers, antioxidants, etc.

[0034] A preferred uron of the present invention is N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea. When used as the primary or sole curing agent for the resin, the uron of the present invention is preferably present in the epoxy resin composition of the present invention in an amount of 2 to 20 wt. %, more preferably 3 to 12 wt. %, and most preferably 4 to 8 wt. %, based on the total weight of the composition.

[0035] The difunctional orthohydroxy aromatic urone of the present invention can be prepared from a precursor obtained by reaction of 2,2-bis(3-amino-4-hydroxyphenyl)propane with 1,1′-carbonyldiimidazole to produce a bisbenzoxazolinone precursor of the following formula:

[0036] [ka]

[0037] This precursor can be reacted with dimethylamine to produce N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea of ​​the following formula:

[0038] [ka] Hereafter, this will be referred to as PBOHFU.

[0039] The di- or polyfunctional orthohydroxy aromatic urone of the present invention has a structure represented by the following formula:

[0040] [ka] In the formula, R1 is S, SO2, SO, P, PX, N, NH, NX, P=O (OX or OH), C=O, a straight-chain or branched-chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20. wherein X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group.

[0041] R2 and R3 are selected at each position independently from one another from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms (preferably chlorine atoms) or hydroxyl or cyano groups, with the proviso that R2 can alternatively represent a hydrogen atom, or R2 and R3 together with the indicated bonding nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring.

[0042] R4 is, at each occurrence, independently selected from H, NH2, NO2, nitrile, halogen, a straight-chain or branched-chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group; and Y is 1 to 3.

[0043] The functionality is determined solely by the number of urea substituents or groups, which in turn are groups or substituents according to the formula -(NH-CO-N(R)2).

[0044] The group R1 in the compound of formula (i) is a bridging unit selected from S, SO2, SO, P, PX, N, NH, NX, P=O (OX or OH), C=O, a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group, where X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group.

[0045] According to the present invention, n in formula (i) can represent a number from 2 to 20. That is, compounds having 2 to 20 urea groups can be used according to the present invention. Preferably, n is an integer from 2 to 10, more preferably n is an integer from 2 to 8, and even more preferably n is 2 or 3. Therefore, according to the present invention, in particular diurons, triurons, or oligourons of general formula (i) having 2, 3, or up to 20 dimethylurea groups, or mixtures thereof, can be used. Diurons with n=2 and triurons with n=3 are particularly preferred. Furthermore, n can be a number from 4 to 20, and oligorons with n=4 to 20 are also preferred. It should be emphasized that the choice of the basic structure is not very critical.

[0046] In another embodiment of the present invention represented by compounds of formulas (ii) and (iii), the difunctional ortho hydroxy aromatic urone may comprise a single aromatic moiety to which are attached two urea substituents bearing hydroxyl groups in the ortho positions relative to the urea substituents.

[0047] In particular, it has been found in accordance with the present invention that urone of the above general formula can be used as the sole curing agent in epoxy resin compositions, and thus, in this embodiment, these epoxy resin compositions do not need to contain additional curing agents, co-curing agents (curing coagents), curing accelerators and / or catalysts for the curing of the epoxy resin.

[0048] The amount of the compound of the present invention used in a resin formulation depends on the desired function of the compound and whether it is used as the primary or sole curing agent, or as an accelerator for another curing agent. The amount can range from 0.01 to 20 parts of the uron of the present invention or a mixture thereof per 100 parts of resin, preferably from 0.1 to 15 parts, more preferably from 1 to 15 parts, and most preferably from 2 to 15 parts per 100 parts of resin. Also preferably, the uron of the present invention is used in an amount of 1 to 12 parts, especially from 2 to 12 parts, more preferably from 3 to 12 parts, particularly preferably from 4 to 12 parts, and most particularly preferably from 5 to 12 parts per 100 parts of resin.

[0049] According to the present invention, by using these amounts, it is possible to generate a maximum heat flow of 0.05 to 0.99 W / g (based on the mass of the epoxy resin) in the epoxy resin composition so that the epoxy resin composition is completely cured at a temperature of 60 to 180°C.

[0050] The present inventors have found that when the compounds of the present invention are used as the primary curing agent for epoxy resin compositions, they can be cured at temperatures of 60 to 190°C, particularly 60 to 180°C, and especially 60 to 160°C, and most preferably 60 to 150°C, and that the curing reaction is controlled so that the epoxy resin composition is fully cured without the generation of excessive heat that could damage the resin and articles made therefrom. When the compounds are used as accelerators for other curing agents, the curing temperature may be at the upper end of the range, such as 150 to 190°C, especially 60 to 180°C.

[0051] An epoxy resin composition is considered to be fully cured when the epoxy resin composition is cured to an extent of ≧80%, preferably ≧90%, more preferably ≧95%, even more preferably ≧98%, particularly ≧99%, and most preferably 100%. Thus, the epoxy groups in the cured epoxy resin composition have reacted to an extent of ≧80%, preferably ≧90%, more preferably ≧95%, even more preferably ≧98%, particularly ≧99%, and most preferably 100%.

[0052] The compositions of the present invention may contain other ingredients conventionally used in epoxy resin formulations, such as impact modifiers and fillers, as described below.

[0053] Impact modifier The composition may also include an impact modifier. Impact modifiers are widely used to improve the impact strength of cured resin compositions, compensating for their inherent brittleness and crack propagation. Impact modifiers can include rubber particles such as CTBN rubber (carboxyl-terminated butadiene-acrylonitrile) or core-shell particles containing rubber or other elastomeric compounds encased in a polymer shell. The advantages of core-shell particles over rubber particles are that they have a controlled particle size of the rubber core for effective toughening, and the grafted polymer shell ensures adhesion and compatibility with the epoxy resin composition. Examples of such core-shell rubbers are disclosed in EP 0985692 and WO 2014 / 062531.

[0054] Alternative impact modifiers may include methyl acrylate-based polymers, polyamides, acrylics, polyacrylates, acrylate copolymers, phenoxy-based polymers, and polyethersulfones.

[0055] Filler Additionally, the composition may contain one or more fillers to enhance the flow properties of the composition. Suitable fillers may include talc, microballoons, floc, glass beads, silica, fumed silica, carbon black, fibers, filaments and recycled derivatives, and titanium dioxide.

[0056] The resin blend for the prepreg of the present invention can be prepared by uniformly mixing the curing agent of the present invention, the resin, and other additives using a pot mill, ball mill, bead mill, roll mill, homogenizer, super mill, homodisper, universal mixer, Banbury mixer, kneader, or the like.

[0057] The resin formulation of the prepreg of the present invention can be a one-component type having both high storage stability and excellent thermosetting properties, and therefore can be suitably used in applications requiring long-term storage or storage in unconditioned equipment at room temperature.

[0058] The resin formulations of the present invention are particularly useful as curable matrices for the production of fiber reinforced articles, such as in prepregs used in the production of wind turbine components and aerospace components such as aircraft wings and fuselages. The formulations can also be used in the production of automotive parts and parts used in shipping (transportation), and in the production of sporting goods such as skis. [Example]

[0059] The invention is illustrated by the following examples in which the following materials were used:

[0060] 2,2-Bis(3-amino-4-hydroxyphenyl)propane and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane were purchased from Tokyo Chemical Industry Co., Ltd. 3,3-Diamino-4,4-dihydroxydiphenyl sulfone (4,4-DDS) was prepared as described in the literature. 1,1-Carbonyldiimidazole was provided by Apollo Scientific. Dyhard UR500 (3,3'-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea) was purchased from Alzchem (see U.S. Pat. No. 9,663,609). U52 (4,4'-methylenediphenylenebis(N,N-dimethylurea) was obtained from Emerald Performance Materials Company. Orthohydroxyfenuron (OHFU) and N-(2-hydroxy-5-nitrophenyl)-N,N'-dimethylurea (5-NOHFU) were prepared as described in US4404356A. MY721, tetraglycidyldiaminodiphenylmethane epoxy resin, LY3581, bisphenol F epoxy resin, MY0610, triglycidyl-m-aminophenol-based epoxy resin, and 4,4'-diphenyldiaminosulfone were obtained from Huntsman Advanced Materials. Bisphenol A epoxy, Epikote 828, was obtained from Brenntag. LY1556, Araldite epoxy resin, was obtained from Huntsman. 5003P, a polyethersulfone thermoplastic resin, was supplied by Sumitomo. The polyamide particles were supplied by Arkema. All other reagents and solvents were supplied by Sigma-Aldrich.

[0061] The following test methods were used on the materials in the examples.

[0062] Dynamic differential scanning calorimetry (DSC) was performed using a TA Q100 instrument from -50 to 350 °C at a heating rate of 10 °C / min to measure the uncured Tg of the resin as well as the onset and peak temperatures. Dynamic DSC was also used to measure the residual enthalpy of the cured formulations for determination of % cure.

[0063] Isothermal differential scanning calorimetry (DSC) was performed using a Mettler Toledo instrument, DSC 1, to measure the time taken to reach peak temperature during curing at various externally applied temperatures.

[0064] Dynamic mechanical analysis (DMA) was performed on the cured resins using a Q800 instrument at a heating rate of 5°C / min, a frequency of 1 Hz, and an amplitude of 30 μm to measure the glass transition temperature.

[0065] Thermogravimetric analysis (TGA-DSC) was performed using a Mettler Toledo TGA / DSC 1 in air from 25 to 350 °C at a heating rate of 10 °C / min to measure the melting point / decomposition temperature.

[0066] Dynamic and isothermal rheology was tested using an Anton Paar MCR92. Dynamic rheology was tested at a heating rate of 2°C / min.

[0067] Outlife was measured by monitoring the uncured Tg of the mixture over time. The mixture was stored in a temperature-controlled incubator set at 23°C.

[0068] The following abbreviations are used: PBOHFU - N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea FPBOHFU - N,N'-[hexafluoropropylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea SBOHFU - N,N'-[sulfonyl(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea DOHFU - 3,3'-(4,6-dihydroxy-1,3-phenylene)bis(1,1-dimethylurea) OHFU - Orthohydroxyfenuron 5-NOHFU - N-(2-hydroxy-5-nitrophenyl)-N,N'-dimethylurea 4,4-DDS - 4,4-Diaminodiphenyl sulfone The results of the tests employed in the examples are shown in Figures 1 to 4 attached hereto.

[0069] Example 1 Preparation of N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, PBOHFU [ka]

[0070] The bisbenzoxazolinone precursor of this formula was first prepared as follows: 25.2 g of 2,2-bis(3-amino-4-hydroxyphenyl)propane and 300 ml of dimethylacetamide were added to a 500 ml round-bottom flask. 57.0 g of 1,1-carbonyldiimidazole was added in portions over 1 hour. The solution was heated to 60°C and stirred at this temperature for 6 hours, after which it was cooled to room temperature. The solution was then poured into 1 liter of deionized water to precipitate the product. 4 M hydrochloric acid was added to the mixture until the solution was slightly acidic. The precipitate was collected by vacuum filtration, washed with deionized water, and then dried overnight in a vacuum oven at 60°C to give 29.7 g of a white powder with a melting point of 278°C in 98.0% yield.

[0071] The product was identified as follows:

number

[0072] PBOHFU of the formula below was prepared as follows: [ka] To a 250 ml round-bottom flask were added 29.7 g of 2,2-bis(3H-1,3-benzoxazol-2-one)propane precursor and 85 ml of 40 wt % aqueous dimethylamine solution. The mixture was heated to 50 °C and stirred at this temperature for a total of 15 hours, then cooled to room temperature. During this time, 80 ml of deionized water was added to dilute the solids and aid in stirring. The mixture was then transferred to a single-neck round-bottom flask, and excess dimethylamine was removed on a rotary evaporator. The mixture was then slightly acidified using 4 M hydrochloric acid. The precipitate was collected by filtration, washed with deionized water, and dried overnight in a vacuum oven at 60 °C to yield 36.1 g of a white powder. The yield was 94.3%, with a melting point of 189 °C (decomposition).

[0073] This formula was confirmed by the following:

number

[0074] Example 2 Preparation of N,N-[hexafluoropropylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, FPBOHFU [ka]

[0075] The above benzoxazolinone precursor was first prepared as follows: 25.0 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 175 ml of dimethylacetamide, and 36.2 g of 1,1-carbonyldiimidazole were used for a reaction time of 2.5 hours, following the same procedure as described in Example 1 to obtain 26.2 g of a white powder with a yield of 91.8% and a melting point of 322°C.

[0076] The product was identified as follows:

number

[0077] Using 26.2 g of 2,2-bis(3H-1,3-benzoxazol-2-one)hexafluoropropane and 50 ml of 40 wt % aqueous dimethylamine solution, uron was prepared by the same procedure as in Example 1, with a reaction time of 2.5 hours, to obtain 17.7 g of a white powder. The yield was 55.6%, and the melting point was 202°C (decomposition). This gave the product of the following formula: [ka]

[0078] This formula was confirmed by the following:

number

[0079] Example 3 Preparation of N,N'-[sulfonyl(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, SBOHFU

[0080] [ka] The benzoxazolinone precursor was first prepared using 5.6 g of 3,3-diamino-4,4-dihydroxydiphenyl sulfone, 50 ml of dimethylacetamide, and 10.3 g of 1,1-carbonyldiimidazole with a reaction time of 4 hours, following the same procedure as in Example 1, to give 6.2 g of a white powder with a yield of 91.2% and a melting point of >350°C.

[0081] The product was identified as follows:

number

[0082] [ka] Using 6.2 g of 2,2-bis(3H-1,3-benzoxazol-2-one) sulfone and 15 ml of 40 wt % aqueous dimethylamine solution, the uron was prepared by the same procedure as in Example 1, with a reaction time of 7 hours, to obtain 6.2 g of a yellow-brown powder in a yield of 79.5% and a melting point of 220°C (decomposition).

[0083] Example 4 Production of 3,3'-(4,6-dihydroxy-1,3-phenylene)bis(1,1-dimethylurea), DOHFU

[0084] [ka] The bisbenzoxazolinone precursor was first prepared. 25.0 g of 4,6-diaminoresorcinol dihydrochloride was added to a 500 ml round-bottom flask and the flask was placed under an inert atmosphere of nitrogen. 300 ml of dimethylacetamide was then added. 16.0 ml of triethylamine was added dropwise to the stirred suspension, followed by 63.4 g of 1,1-carbonyldiimidazole, added in portions over 1 hour. The suspension was heated to 60°C and stirred at this temperature for 2 hours before being cooled to room temperature. The mixture was then poured into 1 L of deionized water to precipitate the product. 4 M hydrochloric acid was added to the mixture until the solution was slightly acidic. The precipitate was collected by vacuum filtration, washed with deionized water, and then dried overnight in a vacuum oven at 60°C, yielding 21.8 g of an off-white powder. The yield was 96.9%, with a melting point of >350°C.

[0085] The product was identified as follows:

number

[0086] [ka] The uron was prepared using 10.1 g of [1,3]-oxazolo[4,5-F][1,3]benzoxazole-2,6-(3H,5H)-dione and 40 ml of 40 wt % aqueous dimethylamine solution, with a reaction time of 2.5 hours, following the same procedure as in Example 1. The product was purified by dissolving in 100 ml of heated dimethylacetamide and filtering. The filtrate was then poured into 250 ml of deionized water. The precipitate was collected by filtration, washed with deionized water, and then dried overnight in a vacuum oven at 60°C, yielding 11.4 g of a burgundy powder. The yield was 77.0%, and the melting point was 233°C (decomposition).

[0087] The product was identified as follows:

number

[0088] Example 5 The products of Examples 1 and 2 were used as curing agents for epoxy resins and compared with standard difunctional urons UR500 and U52, and with the monofunctional orthohydroxyfenurons OHFU and NOHFU. These urons were dispersed in epoxy resin Epikote 828 at an equivalent ratio of uron functional groups to epoxy resin groups of 5.6 mole % uron groups to epoxy groups.

[0089] [Table 1]

[0090] The mixture was cured in a fan oven at 150°C for 1 hour, increasing the temperature at 1°C / min until 150°C was reached. Samples were also post-cured at 180°C for 2 hours to achieve full cure. The results in Table 2 demonstrate that the use of the urons of the present invention exhibits improved ultimate Tg compared to standard urons and monofunctional OHFU.

[0091] [Table 2]

[0092] Reactivity was measured at various cure temperatures by time to peak from isothermal DSC. Table 3 demonstrates that the PBOHFU of the present invention performs comparably, if not slightly better, than the non-hydroxyphenyl difunctional urea U52.

[0093] [Table 3]

[0094] The outlife of the mixtures was followed by monitoring the uncured Tg of the mixtures when held for a given time at 23° C. The graph attached hereto, Figure 1, demonstrates that the outlife performance is similar to that of both the standard difunctional uron and the monofunctional OHFU.

[0095] Furthermore, Table 4 demonstrates that increasing the content of the bis-OHFU of the present invention in the epoxy resin from 5.6 mol % to 10 mol % of uronic groups to epoxy groups significantly improves the Tg compared to using monofunctional OHFU.

[0096] [Table 4]

[0097] As can be seen, PBOHFU exhibits an improved Tg compared to monofunctional OHFU: OHFU only increases the final Tg by 6°C when added at 10 mol% compared to 5.6 mol%, while PBOHFU shows an increase of 11°C at 10 mol% compared to 5.6 mol%.

[0098] Example 6 The product of Example 1 was used as a curing agent for epoxy resins and compared with standard difunctional urons UR500 and U52, and with OHFU as a monofunctional orthohydroxyfenuron. These urons were dispersed in epoxy resin MY721 at an equivalent ratio of uron functional groups to epoxy resin groups of 5.6 mole % uron groups to epoxy groups.

[0099] [Table 5]

[0100] The mixture was cured for 2 hours in a fan oven at 180° C. with a temperature increase of 1° C. / min until 180° C. was reached. The results in Table 6 demonstrate that the use of the urons of the present invention shows improved final Tg post-cure compared to standard urons and monofunctional OHFU.

[0101] [Table 6]

[0102] The outlife of the mixtures in Table 5 was followed by monitoring the uncured Tg of the mixtures when held for a given time at 23° C. The graph, Figure 2 attached hereto, demonstrates that the outlife performance for the products of the present invention is similar to that of the standard difunctional uron and slightly better than the monofunctional OHFU.

[0103] The latency of the mixtures at 80° C. was monitored by isothermal rheology over a 3-hour time frame. The graph in Figure 3 attached hereto demonstrates that the PBOHFU of the present invention exhibits better latency performance at 80° C. than the monofunctional OHFU and approaches that of the standard bifunctional urons UR500 and U52.

[0104] Example 7 The products of Examples 1 and 2 were used as accelerators in 4,4-DDS cure systems and compared to standard bifunctional urons UR200 and U52, and to OHFU as a monofunctional orthohydroxyfenuron, as shown in Table 7.

[0105] [Table 7]

[0106] The mixtures were cured in a fan oven at 180° C. for 45, 75, and 120 minutes, increasing the temperature by 1° C. / min until 180° C. was reached. The results in Tables 8 and 9 demonstrate that the PBOHFU and FPBOHFU of the present invention exhibit similar cure acceleration effects in terms of % cure, while they exhibit improved Tg over all cure cycle times compared to the standard uron and monofunctional OHFU.

[0107] [Table 8]

[0108] [Table 9]

[0109] The formulations were modified by reducing the uron content to those shown in Table 10. Tables 11 and 12 demonstrate how reducing the content of the bis-OHFU of the present invention in a DDS cure system further improves the Tg and also provides good acceleration across all cure cycle times.

[0110] [Table 10]

[0111] [Table 11]

[0112] [Table 12]

[0113] The latency of the mixtures at 100°C was monitored by isothermal rheology over a 3 hour time frame. As demonstrated by the graph in Figure 4 attached hereto, the FBOHFU and PBOHFU of the present invention show consistent latency performance at 100°C at both 1% and 0.50% loadings compared to formulations without accelerator. Various aspects or embodiments that can be included in the present invention are summarized as follows. [1]. A bis-orthohydroxy aromatic uron of a formula selected from the following: [C1] JPEG0007770389000033.jpg94156 (In the formula, R 1 , S, SO 2 , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R 2 and R 3 are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms (preferably chlorine atoms) or by hydroxyl or cyano groups, with the proviso that R 2 may alternatively represent a hydrogen atom, or R 2 and R 3 together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R 4 are, in each case independently of one another, H, NH 2 , NO 2 , nitrile, halogen, straight or branched chain aliphatic group, or unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and Y is 1 to 3; Bis-orthohydroxy aromatic uron. [2]. N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea. [3]. Use of the bis(orthohydroxy)aromatic urone according to item 1 or 2 above as a curing agent for epoxy resins. [4]. Use of the bis(orthohydroxy)aromatic urone according to item 1 or 2 above as an accelerator for epoxy resins or a curing agent for epoxy resins. [5]. The use according to item 3 or 4 in a prepreg. [6]. A resin formulation comprising the bis-orthohydroxy aromatic urone according to item 1 or 2 above in combination with at least one resin component selected from epoxy, polyisocyanate and phenolic resins. [7]. A molding material comprising the resin formulation according to item 6 above in combination with a fiber reinforcing material. [8]. 8. The molding material according to item 7, wherein the fiber reinforcement material is selected from woven fabrics, multiaxial fabrics, individual fiber tows as chopped fibers, staple fibers and / or filaments, and mixtures thereof. [9]. Item 9. The molding material according to item 8, wherein the fiber material is selected from carbon fiber, glass fiber, and aramid.

[10] . A prepreg comprising a fiber reinforcement and the resin formulation described in item 6 above.

[11] . 11. A stack of prepregs according to item 10.

[12] . 12. The stack according to item 11, comprising at least 40 prepregs.

[13] . A process for producing an article, comprising curing the prepreg according to claim 10 or a stack of prepregs according to item 11 or 12.

[14] . 14. The process according to item 13, wherein the curing is induced by an externally applied temperature of 60°C to 190°C.

[15] . 15. The process according to item 13 or 14, carried out in a vacuum bag.

[16] . 15. The process according to claim 13 or 14, wherein the curing is carried out in a press.

[17] . 17. The process according to any one of the above items 13 to 16 for manufacturing a wind turbine component.

[18] . 17. The process according to any one of the above items 13 to 16 for producing an aerospace part.

[19] . A composition comprising an epoxy resin and 2 to 20% by weight of the bis-orthohydroxy aromatic uron according to item 1 above.

[20] . A composition comprising an epoxy resin, a curing agent other than the bis-orthohydroxy aromatic uron described in item 1 above, and 0.1 to 2% by weight of the bis-orthohydroxy aromatic uron described in item 1 above.

[21] . 21. The composition according to item 20, wherein the curing agent other than the bis-orthohydroxy aromatic uron according to item 1 is a primary amine or a secondary amine.

[22] . 22. The composition according to item 21, wherein the primary or secondary amine is selected from ethylenediamine, diethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, tetraethylenepentamine, hexaethyleneheptamine, hexamethylenediamine, cyanoguanidine, 2-methyl-1,5-pentamethylenediamine, 4,7,10-trioxatridecane-1,13-diamine, aminoethylpiperazine, dicyanopolyamide, 4,4'-diaminodiphenylsulfone or 3,3'-diaminodiphenylsulfone, bisaniline, dihydrazide, polyamine, polyetheramine having one or more amine moieties, and mixtures thereof.

[23] . A wind turbine component formed from the molding material according to any one of items 7 to 9 or the composition according to any one of items 19 to 22.

[24] . An aerospace part formed from the molding material according to any one of items 7 to 9 or the composition according to any one of items 19 to 22.

Claims

1. N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea.

2. Use of a difunctional or trifunctional or higher polyfunctional orthohydroxy aromatic uron as a curing agent for epoxy resins, The difunctional or trifunctional or more polyfunctional orthohydroxyaromatic uron is N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, or A difunctional, trifunctional or higher polyfunctional orthohydroxyaromatic uron (other than N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea) of the formula selected from the following: 【Chemistry 1】 (In the formula, R １ is S, SO ２ , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R ２ and R ３ are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms or by hydroxyl or cyano groups, with the proviso that R ２ may alternatively represent a hydrogen atom, or R ２ and R ３ together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R ４ are, in each case independently of one another, H, NH ２ , NO ２ , a nitrile, a halogen, a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and y is 1 to 3. Use of difunctional or trifunctional or more polyfunctional orthohydroxy aromatic urons.

3. Use of a difunctional or trifunctional or higher polyfunctional orthohydroxyaromatic uron as an accelerator for epoxy resins or a curing agent for epoxy resins, The difunctional or trifunctional or more polyfunctional orthohydroxyaromatic uron is N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, or A difunctional, trifunctional or higher polyfunctional orthohydroxyaromatic uron (other than N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea) of the formula selected from the following: 【Chemistry 2】 (In the formula, R １ is S, SO ２ , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R ２ and R ３ are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms or by hydroxyl or cyano groups, with the proviso that R ２ may alternatively represent a hydrogen atom, or R ２ and R ３ together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R ４ are, in each case independently of one another, H, NH ２ , NO ２ , a nitrile, a halogen, a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and y is 1 to 3. Use of difunctional or trifunctional or more polyfunctional orthohydroxy aromatic urons.

4. 4. Use according to claim 2 or claim 3 in a prepreg.

5. A resin formulation comprising a di- or tri- or higher functional orthohydroxy aromatic uron in combination with at least one resin component selected from epoxy, polyisocyanate and phenolic resins, The difunctional or trifunctional or more polyfunctional orthohydroxyaromatic uron is N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea, or A difunctional, trifunctional or higher polyfunctional orthohydroxyaromatic uron (other than N,N'-[propylene(4-hydroxy-3,1-phenylene)]bis(N,N-dimethyl)urea) of the formula selected from the following: 【Transformation 3】 (In the formula, R １ is S, SO ２ , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R ２ and R ３ are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms or by hydroxyl or cyano groups, with the proviso that R ２ may alternatively represent a hydrogen atom, or R ２ and R ３ together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R ４ are, in each case independently of one another, H, NH ２ , NO ２ , a nitrile, a halogen, a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and y is 1 to 3. Resin formulation.

6. A molding material comprising the resin formulation described in claim 5 in combination with a fiber-reinforced material.

7. 7. The molding material according to claim 6, wherein the fiber reinforcement material is selected from woven fabrics, multiaxial fabrics, individual fiber tows as chopped fibers, staple fibers and / or filaments, and mixtures thereof.

8. 8. The molding material according to claim 7, wherein the fibrous material is selected from carbon fibre, glass fibre and aramid.

9. A prepreg comprising a fiber reinforcement and the resin formulation of claim 5.

10. A stack of prepregs as described in claim 9.

11. 11. The stack of claim 10 comprising at least 40 prepregs.

12. A process for manufacturing an article, comprising curing a prepreg as described in claim 9, or a stack of prepregs as described in claim 10 or claim 11.

13. 13. The process of claim 12, wherein the curing is induced by an externally applied temperature of from 60°C to 190°C.

14. 14. The process of claim 12 or claim 13, carried out in a vacuum bag.

15. 14. The process of claim 12 or claim 13, wherein curing is carried out in a press.

16. A process according to any one of claims 12 to 15 for manufacturing a wind turbine component.

17. A process according to any one of claims 12 to 15 for manufacturing an aerospace part.

18. A composition comprising an epoxy resin and 2 to 20% by weight of a difunctional or trifunctional or higher polyfunctional orthohydroxy aromatic uron, The difunctional or trifunctional or more polyfunctional orthohydroxyaromatic uron is A difunctional, trifunctional or higher polyfunctional orthohydroxy aromatic uron of the formula selected from the following: 【Chemistry 4】 (In the formula, R １ is S, SO ２ , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R ２ and R ３ are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms or by hydroxyl or cyano groups, with the proviso that R ２ may alternatively represent a hydrogen atom, or R ２ and R ３ together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R ４ are, in each case independently of one another, H, NH ２ , NO ２ , a nitrile, a halogen, a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and y is 1 to 3. composition.

19. A composition comprising an epoxy resin, a curing agent other than a di-, tri- or higher functional polyfunctional orthohydroxy aromatic uron, and 0.1 to 2% by weight of a di-, tri- or higher functional polyfunctional orthohydroxy aromatic uron, The difunctional or trifunctional or more polyfunctional orthohydroxyaromatic uron is A difunctional, trifunctional or higher polyfunctional orthohydroxy aromatic uron of the formula selected from the following: 【Transformation 5】 (In the formula, R １ is S, SO ２ , SO, P, PX, N, NH, NX, P═O (OX or OH), C═O, a linear or branched aliphatic group (substituted or unsubstituted), or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and n is a number from 2 to 20; X is a straight or branched chain aliphatic group (substituted or unsubstituted), or an unsubstituted, halo- and / or alkyl-substituted aromatic group; R ２ and R ３ are, in each occurrence independently of one another, selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aralkyl groups, optionally substituted by halogen atoms or by hydroxyl or cyano groups, with the proviso that R ２ may alternatively represent a hydrogen atom, or R ２ and R ３ together with the indicated attached nitrogen atom represent a heterocycle containing 3 to 5 carbon atoms and optionally 1 oxygen atom in the ring; R ４ are, in each case independently of one another, H, NH ２ , NO ２ , a nitrile, a halogen, a straight or branched chain aliphatic group, or an unsubstituted, halo-substituted and / or alkyl-substituted aromatic group, and y is 1 to 3. composition.

20. 20. The composition of claim 19, wherein the curing agent other than a di- or tri- or higher functional orthohydroxy aromatic urone is a primary or secondary amine.

21. 21. The composition of claim 20, wherein the primary or secondary amine is selected from ethylenediamine, diethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, tetraethylenepentamine, hexaethyleneheptamine, hexamethylenediamine, cyanoguanidine, 2-methyl-1,5-pentamethylene-diamine, 4,7,10-trioxatridecane-1,13-diamine, aminoethylpiperazine, dicyanopolyamides, 4,4'-diaminodiphenyl sulfone or 3,3'-diaminodiphenyl sulfone, bisanilines, dihydrazides, polyamines, polyetheramines having one or more amine moieties, and mixtures thereof.

22. A wind turbine component formed from the molding material according to any one of claims 6 to 8 or the composition according to any one of claims 18 to 21.

23. An aerospace part formed from a molding material according to any one of claims 6 to 8 or a composition according to any one of claims 18 to 21.

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