MX2014007819A - Blends for composites. - Google Patents

Abstract

The present invention relates to a blend containing an epoxy resin, a cyclic carbonate and a hardener containing a polyalkoxypolyamine, an additional amine and a catalyst, a process for producing this blend, the use of the blend according to the invention for producing cured epoxy resin and an epoxy resin which has been cured by means of the blend according to the invention, in particular fibre-reinforced cured epoxy resins for use in rotor blades for wind turbines.

Description

MIXES FOR COMPOSITE MATERIALS DESCRIPTION The object of the present invention relates to a mixture comprising an epoxy resin, a cyclic carbonate, and a hardener comprising a polyalkoxypolyamine, another amine, and a catalyst, to a process for producing said mixture, to the use of the mixture of the invention for the production of cured epoxy resin, and also an epoxy resin cured with the mixture of the invention, and in particular cured epoxy resins reinforced with fiber for use in rotor blades for wind turbines.

Mixtures made of curable epoxy compositions and use thereof for the production of composite materials are known and described in numerous patent publications and other literature, for example, in "Handbook of Epoxy Resins", McGraw-Hill 1967, of H Lee and K. Neville. If the components and the quantitative proportions of these are selected properly with respect to each other in mixtures comprising epoxy resins and curing agents (hardeners), these can be reacted to give, after hardening of the mixtures, materials known as resins Cured epoxies having very good mechanical properties, as described in EP-A 2307358.

Traditional hardeners for epoxy resins are amines. The use of amines to cure epoxy resins is found, among other things, in what is known as infusion technologies, particularly in VARTM processes. Here, the di and polyepoxy resins are mixed with amines immediately before the loading process to give the mixture, the mixture is sucked or pumped at temperatures of 20 ° C to 50 ° C in a mold, and then reacted at mold temperatures of 55 ° C to 90 ° C, with the hardening of the resulting mixture. The speed of the entire process in the present depends on the duration of the loading stage, the actual infusion, and the duration of the hardening process.

An important application area specific for cured epoxy resins is the use for the production of components made of fiber-reinforced plastic where the mechanical reinforcement is supplied by glass fibers, or by carbon or other fibers. Fiber-reinforced plastics are used as materials for motor vehicles, for aircraft, ships and boats, and for sporting goods and rotor blades of wind turbines.

In recent years, the dimensions of rotor blades of wind turbines have increased, and this has also led to more stringent requirements, in particular in relation to the mechanical properties of the mixtures that, after a complete cure, produce the rotor blades, and have to meet the strictest technical requirements. The industrial production of rotor blades for wind turbines in general, uses the process of vacuum infusion or "vacuum assisted resin transfer molding" process (VARTM.). An increase in the level of mechanical properties of The mixtures can be achieved by using the cyclic carbonates described in "Technical Bulletin JEFFSOL ® CARBONATES IN EPOXY FORMULATIONS", Huntsman, 2005.

In the production of lightweight composite workpieces such as rotor blades of wind turbines, for example, it is common to have light construction materials such as balsa wood or, in particular, PVC foam in a structure of layers with reinforcing fibers and curable epoxy resin compositions. After curing the epoxy resin composition, the PVC foam can then react, depending on the epoxy resin composition used, with discoloration. Such color changes in PVC have been described (H. Wechsler, Journal of Polymer Science, 11 (1953), 233).

WO2010 / 0100 describes mixtures of a resin component and a hardening component comprising not only amine hardeners comprising polyether polyamine and are used in a less than stoichiometric amount, but also a catalytic hardener based on guanidine, especially for use in large composite components.

The cyclic carbonates described in US 3,305,527 are good reactive diluents for epoxy resins. The blends described in US 3,305,527, which comprise liquid amines as hardeners at temperatures of 20 ° C to 50 ° C, increase the reactivity of the epoxy resin. However, an essential factor for the production of large parts, such as wind turbines, is that the viscosity of the mixture does not increase quickly enough to be a cause of improper wetting of the fibers or failure to achieve a Complete filling of the mold with the mixture before the cure has proceeded through the mixture to a point that prevents processing. The relevant mixtures described in US 3, 305, .527 can not, therefore, be used in large components produced by means of the V7ARTM technology, due to excessive reactivity and therefore excessively fast hardening.

The "Technical Bulletin JEFFSOL ® CARBONATES IN EPOXY FORMULATIONS", Huntsman, 2005, likewise says that cyclic carbonates are known to reduce the thermal stability of mixtures. Thermal stability is described by means of heat deformation temperature (HDT), which is required by Germanischer Lloyd to be above 70 ° C for a cured mixture. Germanischer Lloyd is responsible for the certification procedures that are a requirement for the construction of wind turbines. Said heat deflection temperatures for the relevant mixtures described in US 3,305,527 are below 65 ° C. JP 2002-187936 also describes mixtures, which comprise three components, namely an epoxide, an amine, and a tertiary amine, wherein the ratio of active hydroquinone atoms to epoxy groups is intended to be in the range of 0.3. at 0.8 and the weight ratio of tertiary amines to epoxy resin is intended to be in the range of 0.001 to 0.1. JP 2002-1 87936 does not disclose mixtures also comprising cyclic carbonates, together with the epoxide.

WO-A1 2011/112405 discloses a process for reducing exothermicity, wherein cyclic carbonates, in particular, propylene carbonate, and a hardener, are used in conjunction with epoxides. The hardener is preferably one selected from the group of a cyclic aliphatic amine, such as IPDA, and a polyalkoxypolyamine. There is no description of a combination, within the mixture, of at least three compounds bearing nitrogen atoms and which can also be used in a lower than stoichiometric ratio in relation to the all of cyclic carbonate and epoxy groups, wherein the mixture, however, has the desired mechanical properties after curing.

Therefore, the object of the present invention is to provide a mixture that retains sufficient flow capacity so that the VARTM process allows the production of large fiber-reinforced molding parts, in particular rotor blades for wind turbines, but which achieves second complete hardening within a short period of time and also meets or exceeds the rigorous mechanical demands required for the use of large fiber-reinforced molding parts, for example greater tensile strength, deformation by stress at breaking and resistance to bending, and also thermal stability. There is sufficient flow capacity especially when the initial viscosity of the mixture (at 25 ° C, for example) is comparatively low and the viscosity of the mixture rises slowly at elevated temperature (at 40 ° C, for example). It is also desirable that the discoloration of the PVC foam, as far as possible, be avoided when the mixture is cured, in the case of composite molded bodies comprising PVC foam. An additional desire is that the cured mix moldings not only have good static mechanical properties, but also good dynamic stability.

Said object is achieved through a mixture comprising a) an epoxy resin component comprising a) from 75 to 97 parts by weight, based on the epoxy resin component a), of one or more epoxy resins selected from the group of aromatic epoxy resins and / or cycloaliphatic epoxy resins , Y a2) from 3 to 18 parts by weight, based on epoxy resin component a), of one or more cyclic carbonates selected from the group of cyclic carbonates having from 1 to 10 carbon atoms, and a3) from 0 to 15 parts by weight, based on the epoxy resin component a), of one or more reactive diluents, where the parts by weight of the components a) to a3) always give a total of 100, and b) a hardener comprising bl) from 10 to 79 parts by weight, based on hardener b), of one or more polyalkoxypolyamines, and b2) from 20 to 89 parts by weight, based on hardener b), of one or more amines selected from the group consisting of aromatic, arylaliphatic, cycloaliphatic, heterocyclic and aliphatic polyamines having at least 3 carbon atoms and at least 4 functions NH reactive in primary and / or secondary amino groups, and b3) from 0.5 to 30 parts by weight, based on hardener b), of one or more catalysts selected from the group of tertiary amines, imidazoles, guanidines, imidazolines having less than 3 carbon atoms and / or less than 4 NH reactive functions on amino groups, secondary amines having less than 4 reactive NH functions, urea compounds and ketimines, where the parts by weight of components b1) to b3) always give a total of 100, where the ratio of amino equivalents of the hardener b) the equivalent of the total epoxy resin, reactive diluent and cyclic carbonate in the component of epoxy resin a) used is in the range of 0.3 to 0.9, where the reactive diluents a3) are those selected from the group of ether 1, -butanediol bisglycidyl, 1, 6-hexanediol bisg] icidyl, neodecanoate glycidyl, glycidyl versatate, 2-ethylhexyl glycidyl ether, Cs-Cio alkyl glycidyl ether, C12-C14 alkyl glycidyl ether, C13-C15 alkyl glycidyl ether, p-tert-butyl glycidyl ether, butyl ether glycidyl, nonylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether, polyoxypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether (TMP), triglycidyl glyceryl ether, paraaminophenol triglycol cidyl (TGPAP), divinyl benzyl dioxide and dicyclopentadiene diepoxide.

For the purposes of the present invention, NH functionality means the number of reactive hydrogen atoms in the amino groups of a compound. Accordingly, for example, a primary monoamine has an NH functionality of 2, a primary diamine an NH functionality of 4, and an amine having 3 secondary amino groups an NH functionality of 3. In an advantageous embodiment of the mixture of the invention , the epoxy resins a) are those selected from the group of bisphenol A, bisglycidyl ether and / or bisphenol F bisglycidyl ether.

In an advantageous embodiment of the mixture of the invention, the cyclic carbonates a2) are propylene carbonate and / or ethylene carbonate and / or butylene carbonate.

In an advantageous embodiment of the mixture of the invention, the reactive diluents a3) are those selected from the group of 1,4-butanediol bisglycidyl ether, ether 1, β-hexanediol bisglycidyl, C12-C14 glycidyl alkyl ether, C13-C15 alkyl glycidyl ether and trimethylolpropane triglycidyl ether (TMP).

In an advantageous embodiment of the mixture of the invention, the reactive diluents a3) are those selected from the group of ether 1, -butanediol bisglycidyl, ether 1,6-hexanediol bisglycidyl, alkyl ether of C 12 -C 14 -alkyl ether, ether of C 13 -C 15 alkyl glycidyl.

In an advantageous embodiment of the mixture of the invention, the polyalkoxypolyamine bl) is one selected from the group of Polyetheramines D230 (D230), Polyetheramines D400, Polyetheramine T 403, Polyetheramines T 5000 and Jeffamine ® XT J-568 (XT 568 J). In an advantageous embodiment of the mixture of the invention, the other amine b2) is isophoronediamine (IPDA) and / or a mixture of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine (MDACH).

In an advantageous embodiment of the mixture of the invention, the catalyst of b3) is one selected from the group of tetramethylguanidine (TMG), 2,4,6-tris (dimethylaminomethyl) phenol (DMP), 1,4-diazabicyclo [2.2.2] octane (DABCO), and a mixture thereof.

In an advantageous embodiment of the mixture of the invention, the viscosity of the mixture of the invention at 25 ° C is less than 350 mPas. If this viscosity is too high for a mixture, then the flowability of the mixture is no longer sufficient for the production of large molded parts of composite material, by means of VARTM processes, for example.

In an advantageous embodiment of the mixture of the invention, the viscosity increase at 40 ° C requires more than 90 minutes to reach 1000 mPas. If this time period is too low for a mixture, then the flow capacity of the mixture is no longer sufficient for the production of large molded pieces of composite material, by means of VARTM processes, for example.

In an advantageous embodiment of the mixture of the invention, the mixture of the invention also comprises reinforcing fibers. The invention further provides a process for the production of the mixture of the invention, wherein the epoxy resin component a) and the hardener b) are mixed at temperatures below the initial curing temperature. The invention provides the use of the mixture of the invention for the production of cured epoxy resins.

In an advantageous embodiment of the use of the invention, cured epoxy resins are moldings.

In an advantageous embodiment of the use of the invention, the molding comprises reinforcing material.

The present invention further provides a cured epoxy resin obtainable by curing the mixture of the invention, when HDT of the cured epoxy resin is above 70 ° C.

In an advantageous embodiment of the cured epoxy resin of the invention, the cured epoxy resin is a molded part.

The invention further provides a molding that has fiber reinforcement. In an advantageous embodiment of the molding of the invention, which can be obtained through hardening in a mold that has been coated with a fiber-reinforced material, and the introduction of the mixture of the invention by means of VARTM technology in the mold.

In an advantageous embodiment of the molding of the invention, the molding is a reinforced component for the rotor blades of the wind turbines.

The blends of the invention comprise a resin of component a), which comprises at least one epoxy resin a) and a cyclic carbonate a2). The mixture of the invention can use, as epoxy resins a), any of the epoxy resins selected from the group of bisphenol A bisglycidyl ether (DGEBA), bisphenol F bisglycidyl ether, bisglycidyl ether of bisphenol A of hydrogenated ring, ether bisphenol F of bisglycidyl hydrogenated ring, bisphenol A bisglycidyl ether (DGEBS), tetraglycidylmethylenedianiline (TGMDA), epoxy novolaks (the reaction products of epichlorohydrin and phenolic resins (novolac)), epoxy cycloaliphatic resins, such as 3,4-epoxycyclohexanecarboxylate 3, 4-epoxycyclohexylmethyl and diglycidyl hexahydrophthalate. The epoxy resins a) are preferably those selected from the group of bisphenol A bisglycidyl ether, bisphenol F bisglycidyl ether, and mixtures of these two epoxy resins. It is possible to use one or more epoxy resins a) in the mixtures of the invention. It is preferable to use only an epoxy resin al).

The epoxy resin component a) on the other hand, also implies, together with the epoxy resins a), the use of one or more cyclic carbonates a2). The cyclic carbonates a2) in the present are those selected from the group of cyclic carbonates having from 1 to 10 carbon atoms, preferably ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate and glycerol carbonate. One or more cyclic carbonates can be used as cyclic carbonate a2) in epoxy resin component a). It is preferable to use a cyclic carbonate a2). It is particularly preferable to use propylene carbonate as cyclic carbonate a2).

The reactive diluents a3) may also be present together with the epoxy resins a) and the cyclic carbonates a2) in the epoxy resin component a) of the mixture of the invention. Said reactive diluents a3) of the present are those selected from the group of bis-glycidyl 1,2-butanediol ether, 1,6-hexanediol bisglycidyl ether, glycidyl neodecanoate, glycidyl versatate, 2-ethylhexyl glycidyl ether, alkyl glycidyl ether of Cs-Cio, C12-C14 alkyl glycidyl ether, C13-C15 alkyl glycidyl ether, p-tert-butyl glycidyl ether, butyl glycidyl ether, nonylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, Phenyl glycidyl ether, o-cresyl glycidyl ether, polyoxypropylene ether diglycidyl glycol, trimethylolpropane, glycolidilic ether (TMP.), triglycidyl glyceryl ether, triglycidyl-p-aminophenol (TGPAP), divinylbenzyl dioxide and dicyclopentadiene diepoxide The reactive diluents a3) are preferably those selected from the group of ether 1 , Bis-glycidyl 4-butanediol, bis-glycidyl 1,1-hexanediol ether, C12-C1 alkyl glycidyl ether, C 13 -C 15 alkyl glycidyl ether, and mixtures of said compounds. Again in the case of reactive diluents a3), it is possible to use one or more reactive diluents. It is preferable to use a maximum of a reactive diluent.

The respective proportion of the epoxy resins a), the cyclic carbonates a2) and the reactive diluents optionally used a3), in the epoxy resin component, is a characteristic that is very critical for the mixture of the invention in order to achieve , within the resulting cured epoxy resin or the corresponding molding, the physical characteristics required for a cured epoxy resin consisting of a mixture intended for transformation by means of VARTM processes, examples being tensile strength and tensile stress at rupture values.

Accordingly, the proportion of epoxy resin a) for the mixture of the invention is in the range of 75 to 97 parts by weight, preferably in the range of 80 to 95 parts by weight, particularly preferably in the range of 85 to 94 parts by weight, based on epoxy resin component a).

The proportion of the cyclic carbonates a2) for the mixture of the invention is in the range of 3 to 18 parts by weight, preferably in the range of 5 to 15 parts by weight, particularly preferably in the range of 6 to 13 parts by weight , based on epoxy resin component a).

In a particular embodiment of the mixture of the invention, the proportion of the cyclic carbonates a2) is in the range of 6 to 18 parts by weight, and the cyclic carbonate a2) is preferably propylene carbonate. Another characteristic of these mixtures is that the hardened epoxy resins have particularly good dynamic stabilities.

As a measure of dynamic stability, fatigue resistance can be employed. It can be determined in a long-term vibration test of Wóhler. For this purpose, a test element is cyclically loaded, usually under a voltage that is sinusoidal with time. The test is carried out until the test elements are broken, under a constant stress of amplitude in each case. The amplitude of the effort used in each case, with the number of load cycles reached until the break (number of load cycles), produces a characteristic line of the material under test (Wohler line). The dynamic stability is comparatively high when a comparatively high cycle number load is achieved for a defined voltage amplitude, or when a defined number of load cycles with a comparatively high voltage amplitude is achieved.

The proportion of the reactive diluents a3) is also in the range from 0 to 15 parts by weight, preferably from 0 to 10 parts by weight, based on an epoxy resin component a).

The selection of the proportions of the individual groups of a) to a3) within the epoxy resin component a) must be such that the parts by weight of the groups a) to a3) give a total of 100.

In the preferred combinations, a) is in the range of 75 to 97 parts by weight, a2) is in the range of 3 to 18 parts by weight, and a3) is in the range of 0 to 15 parts by weight, based on each case in the epoxy resin component a). In a particularly preferred embodiment, a) is in the range of 80 to 95 parts by weight, a2) is in the range of 5 to 15 parts by weight and a3) is in the range of 0 to 10 parts by weight, based on each case of epoxy resin component a). In a very modality particularly preferred, a) is in the range of 85 to 94 parts by weight, a2) is in the range of 6 to 13 parts by weight, and a3) is in the range of 0 to 10 parts by weight, based on epoxy resin component a), and all of the groups al) and a2) gives a total of 100.

The mixtures of the invention also comprise, together with the epoxy resin component a), a hardener b). The hardener a) in turn comprises at least one polyalkoxy phenylamine b), at least one other b2 amine, selected from the group of aromatic, arylaliphatic, cycloaliphatic, heterocyclic and aliphatic polyamines having at least 3 carbon atoms and at least 4 NH functions reagents in primary and / or secondary amino groups, and at least one catalyst b3).

The polyalkoxypolyamines a) can be selected here from the group of 3,6-dioxa-l, 8-octanediamine, 4,7, 10-trioxa-1, 13-tridecanediamine, 4,7-dioxa-1, 10-decanediamine, , 9-dioxa-l, 12-docecanediamine, polyetheramines based on triethylene glycol with average molecular weight 148, difunctional, primary polyetheramine produced by amination of an ethylene glycol of propylene-oxidegrafted with average molecular weight 176, difunctional, primary polyetheramine based on oxide of propylene with a molecular weight average 4000, difunctional primary polyetheramine, produced by amination of a glycol of polyethylene-propylene oxide grafted with an average molecular weight 2000, aliphatic polyetheramine based on propylene oxide grafted with polyethylene glycol with an average molecular weight of 900, aliphatic polyetheramine based on polyethylene glycol oxide grafted with propylene of average molecular weight 600, difunctional primary polyetheramine produced by amination of a propylene-grafted diethylene glycol oxide with an average molecular weight of 220, aliphatic polyetheraminine based on a copolymer of poly (tetramethylene glycol ether) and polypropylene glycol with an average molecular weight of 1000, aliphatic polyetheraminine based on a poly (polymer) copolymer tetramethylene glycol ether) and polypropylene glycol with an average molecular weight of 1900, aliphatic polyetheramine based on a copolymer of poly (tetramethylene glycol ether) and polypropylene glycol or with average molecular weight 1400, polyethertriamine based on butylene oxide grafted to the alcohol at least trivalent with a heavy weight average number of 400, aliphatic polyetheramine produced by amination of alcohols grafted with butylene oxide with average molecular weight 219 (Jeffamine® XT J 558 (XT J 568)), polyetheramine based on pentaerythritol and propylene oxide with an average molecular weight of 600 , difunctional, primary polyetheramine based on polypropylene glycol with an average molecular weight of 2000, difunctional polyetheramine, primary based on polypropylene glycol with average molecular weight 230 (D230), difunctional, primary polyetheramine based on polypropylene glycol with an average molecular weight of 400 (D400), trifunctional, primary polyetheramine produced by the reaction of propylene oxide with trimethylolpropane followed by amination of the OH groups terminals with an average molecular weight of 403 (T403), the trifunctional primary polyetheramine, produced by the reaction of propylene oxide with glycerol followed by amination of the terminal OH groups with an average molecular weight of 5000 (T 5000) and a polyetheramine with molecular weight 400 medium produced by polyTHF amination having an average molecular weight of 250. The preferable polyalkoxypolyamines bl) are those selected from the group of polyetheramine D230 (D230), polyetheramine D400, polyetheramine T 403, polyetheramine T 5000, Jeffamine ® XT J 568 ( XT J 568), and mixtures thereof. The hardener b) can use any of them or more than one polyalcoxypolyamine bl). It is preferable to use only one polyalkoxypolyamine as bl). It is very particularly preferable that the polyalkoxypolyamine b) is polyetheramine D230 (D230) and / or Jeffamine ® XT J 568 (XT J 568).

The hardener b) also comprises, together with the polyalkoxypolyamines b1), at least one other amine b2). Polyalcoxypolyamines bl) are not to be included in the group of the other amines b2). The other amines b2) here they may be selected from the group of 1,12-diaminododecane, 1, 10-diaminodecane, 1,2-diaminocyclohexane, 1,2-propanediamine, 1,3-bis (aminomethyl) cyclohexane, 1,3-propanediamine, l- methyl-2, 4-diaminocyclohexane, 2,2'oxybis (ethylamine), 3,3 '-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-methylenedianiline, 4-ethyl-4-methylamino-1-octylamine, diethylenetriamine, ethylenediamine, hexamethylenediamine, isophoronediamine, a mixture of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine (MDACH), mindndiamine, xylylenediamine, N-aminoethylpiperazine, neopentanediamine, norbornanediamine, octanethylenediamine, piperazine, 4,8-diaminotricyclo [5.2.1.0] decane, toluylenediamine, triethylenetetramine, and trimethylhexamethylenediamine. It is preferable that the other amines b2) are those selected from the isophoronediamine group (IPDA), a mixture of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine (MDACH), and mixtures thereof. amines Particular preference is given to the mixture of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1,3-diamine (MDACH) as another amine b2) in the hardener b) of the mixture of the invention.

The hardener b) of the mixture of the invention also always has to comprise a catalyst b3) together with polyalkoxypolyamine b) and the other amine b2). The catalyst b3) is selected from the group of tertiary amines, imidazoles, guanidines, imidazolines having less than 3 carbon atoms and / or less than 4 reactive NH functions on amino groups, secondary amines having less than 4 reactive NH functions, urea compounds, and ketimines. The catalyst b3) is preferably selected from the group of tertiary amines, imidazoles, guanidines having less than 3 carbon atoms and / or less than 4 reactive NH functions in amino groups, and urea compounds. More preferably, the catalyst b3) is selected from the group of tertiary amines and guanidines having less than 3 carbon atoms and / or less than 4 reactive NH functions in amino groups.

Tertiary amines are, for example, N, N-dimethylbenzylamine, 2,4,6-tris (dimethylaminomethyl) phenol (DMP 30), 1,4-diazabicyclo [2.2.2] octane (DABCO), 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), S-triazine (Lupragen N 600), bis (2-dimethylaminoethyl) ether (Lupragen N 206), pentamethyldiethylenetriamine (Lupragen N 301), trimethylaminoethylethanolamine (Lupragen N 400), tetramethyl -1,6-hexanediamine (Lupragen N 500), aminoethylmorpholine, aminopropylmorpholine, aminoethylethyleneurea or N-substituted alkyl piperidine derivatives. The imidazoles are imidazole itself and its derivatives such as, for example, 1-methylimidazole, 2-methylimidazole, N-butylimidazole, benzimidazole, C 1-12 alkyl N-alkylimidazoles, N-arylimidazoles, 2,4-ethylmethylimidazole, 2-phenylimidazole, 1- cyanoethylimidazole or N-aminopropylimidazole. The imidazolines are imidazolines as such and their derivatives such as, for example, 2-phenylimidazoline. Guanidines having less than 3 carbon atoms and / or less than 4 NH functions reactive on amino groups are guanidine as such or its derivatives such as, for example, methylguanidine, dimethylguanidine, trimethylguanidine, tetramethylguanidine (TG), methyl isobiguanide, dimethyl isobiguanide, tetramethyl isobiguanide, hexamethyl isobiguanide, heptamethyl isobiguanide or dicyandiamine (DICY). Secondary amines having less than 4 reactive NH functions are, for example, N, N'-diisopropyl isophorone diamine (Jefflink ® XT J-584), N, N'-diisobutyl-4,4'-diaminodicyclohexylmethane (Ciearlink 1000), N - (hydroxyethyl) aniline, di (2-methoxyethyl) amine, piperidine or dialkylamines such as di (2-ethylhexyl) amine, dibutylamine, dipropylamine, ditridecylamine. The urea compounds are the urea itself and its derivatives such as, for example, 3- (-chlorophenyl) -1,1-dimethylurea (monuron), 3-phenyl-1,1-dimethylurea (fenuron), 3- (3 , 4-dichlorophenyl) -1, 1-dimethylurea (diuron), 3- (3-chloro-4-methylphenyl) -1, 1-dimethylurea (chlorotoluron), and tolyl-2,4-bis-N, N-dimethylcarbamide (Amicure UR2T). Ketimines are, for example, Epi-Kure 3502 (a reaction product of ethylenediamine with methyl isobutyl ketone).

It is preferable that the b3) catalyst is one selected from the group of tetramethylguanidine (TMG), 2,4,6-tris (dimethylaminomethyl) phenol (DMP 30) and 1,4-diazabicyclo [2.2.2] octane (DABCO). In a particular embodiment, the catalyst of b3) is TMG and / or DMP 30. In a further preferred embodiment, the catalyst b3) is DABCO.

The respective proportion of the polyalcoxypylamine bl), the other amine b2) and the catalyst b3) is a very critical feature in order to obtain the desired physical properties in the curing mixture of the invention.

The proportion of the polyalkoxypolyamines b1) is in the range of 10 to 79 parts by weight, based on hardener b), preferably in the range of 20 to 70 parts by weight, based on hardener b), particularly preferably on the hardener b). range from 20 to 60 parts by weight, based on hardener b), in particular in the range of 22 to 58 parts by weight, based on hardener b).

The proportion of other amines b2) in the hardener b) in the mixture of the invention is in the range of 20 to 89 parts by weight, preferably in the range of 29 to 79 parts by weight, and particularly preferably in the range of 30. to 60 parts by weight, based on hardener b).

The proportion of the catalyst b3) in the hardener b) of the mixture of the invention is in the range of 0.5 to 30 parts by weight, based on hardener b). The lower limit of this range is preferably 1, more particularly 2, more particularly 4 parts by weight. The upper limit of this range is preferably 20 parts by weight.

In a particular embodiment of the mixture of the invention, the proportion of the catalyst b3) in the hardener b) is in the range of 0.5 to 7 parts by weight, preferably in the range of 1 to 5 parts by weight, based on each case in the hardener b), and the catalyst b3) is preferably of DPM-30 and / or DABCO, more preferably DABCO. Another characteristic of these mixtures is that when they are cured, in the case of PVC containing molded parts of composite material, the discoloration of PVC is avoided to a particularly effective degree.

The selection of the proportions of the individual groups bl) to b3) within the hardener b) must be such that the parts by weight of the groups bl) to b3) give a total of 100.

The preferred constitutions of the groups b1 to b3 within the hardener b) are those having the polyalkoxypolyamines b1) in the range of 1 to 79 parts by weight, the other amines b2) in the range of 20 to 89 parts in weight, and catalysts b3) in the range of 0.5 to 30 parts by weight, based in each case on hardener b). Preference is given to those having constitutions polyalkoxypolyamines b) in the range of 20 to 70 parts by weight, the other amines b2) in the range of 29 to 79 parts b weight, and catalyst b3) in the range of 1 to 20, based in each case on the hardener b).

The mixture of the invention is mixed by mechanical methods known to the person skilled in the art, from the individual constituents, at temperatures below 160 ° C, preferably in the range of 5 to 30 ° C.

In one embodiment of the present invention, the viscosity of the mixture is less than 500 mPas at 25 ° C, preferably less than 400 mPas at 25 ° C, more preferably less than 350 mPas at 25 ° C.

It is preferable that the time required for the mixture of the invention to reach a viscosity of 1000 mPas at 40 ° C, measured in accordance with DIN 16 945, is longer than 50 minutes, preferably greater than 80 min, with particular preference more than 90 minutes.

The heat deformation temperature (HDT (determined according to ISO 75 A)) of the mixture of the invention, after complete hardening, is above 70 ° C.

The complete hardening of the mixture of the invention gives a cured epoxy resin. The tensile strength of the cured epoxy resin (determined in accordance with ISO 527) is greater than or equal to 70 MPa, preferably greater than 74 MPa, particularly preferably greater than 78 MPa.

The tension modulus of the cured epoxy resin of the invention (determined in accordance with ISO 527) is greater than or equal to 3100 MPa, preferably greater than 3200 MPa, particularly preferably greater than 3300 MPa.

The strain strain at the break of the cured epoxy resin of the invention (determined in accordance with ISO 527) is greater than 6.0%, preferably greater than 6.5%, particularly preferably greater than 7%. The flexural strength of the cured epoxy resin of the invention (determined in accordance with ISO 178) is greater than 110 MPa, preferably greater than 115 MPa, more preferably greater than 120 MPa, especially greater than 125 MPa.

The curing modulus of the cured epoxy resin of the invention (determined in accordance with ISO 178) is greater than 3200 MPa, preferably greater than 3300 MPa, particularly preferably greater than 3400 MPa.

The combination of tensile strength, stress strain at break, resistance to bending and, in particular, is comparatively good for the cured epoxy resins comprising the blends of the invention. The mixtures of the invention have the particularity that the cured epoxy resins which can be obtained from the combination of tensile strength figures of at least 70 MPa with the comparatively high strain of the tensile stress values, for example , at least 8.0% and / or with comparatively high flexural strength figures of, for example, at least 120 MPa.

The invention further provides a process for the production of the mixture of the invention, wherein the epoxy resin component a) is mixed with the hardener b) at temperatures below the set cure temperature.

The initial healing temperature is the temperature at which a mixture of a) + b) reacts. This temperature can be determined as TR0E in accordance with DIN 53765 by using a DSC.

When the mixture of the invention is used, the curing speed can be compared with that of known mixtures of the prior art.

The invention further provides the use of the mixture of the invention for the production of cured epoxy resins, preferably in the form of moldings. These cured epoxy resins may comprise reinforcing fibers.

The invention further provides the process for the production of cured epoxy resin in which the mixture of the invention is cured at a temperature greater than or equal to the initial cure temperature, preferably greater than or equal to the initial cure temperature, more of 20 ° C. These cured epoxy resins may comprise reinforcing fibers. The production of moldings of the cured epoxy resin of the invention is additionally provided. In that case, in a preferred embodiment, the mixture of the invention is introduced by means of VARTM technology into the mold, to cure in order to form the molded part.

The present invention further provides the cured epoxy resin, which can be obtained or obtained by curing the mixture of the invention at a temperature greater than or equal to the curing temperature as a whole, preferably greater than or equal to the temperature of healing start plus 20 ° C. For this, the mixtures of the invention are either well charged to specific molds or are applied to the surfaces, and harden through increasing the temperature. The constitution of the mixtures for application to surfaces may also comprise other fillers within the mixture. These charges are those selected from the group of agents with thixotropic effect (pyrolysis silicas for example, hydrophilic and hydrophobic), UV stabilizers (for example, nanoscale oxides, such as titanium dioxide and zinc oxide), flame retardants (eg, polyphosphates and phosphorus), silicates, and carbonates for improve the mechanical properties. Said fillers can be composed, either in epoxy resin component a) or in hardener b), or can be mixed as component c) in the mixture of the invention. The molds used, in which the mixture of the invention is introduced, may contain reinforcing fiber material or else the elements that have to be protected from environmental effects, such as humidity, oxygen, dust or other materials conditions. aggressive or effects.

The curing of the mixtures of the invention for curing epoxy resins that can be produced either within a mold or without restriction, out of any mold. The preferred cured epoxy resins are those hardened in a molding part. These molding pieces are those selected from the group of molding parts for motor vehicles, for aircraft, for ships, for boats, and for sports equipment, and for the blades of wind turbines. Particular preference is given to the molding parts for the rotor blades of the wind turbines.

The design of said molding parts may include, or omit, a reinforcing fiber material, and / or the The mixture of the invention may also comprise reinforcing fiber materials. The reinforcing fiber materials may comprise textile, uni- and multiaxial canvases, non-woven fabric, and short fibers made of the following fiber materials: glass fibers, carbon fibers or aramid fibers, PE fibers (Dyneema), and basalt fibers. Preference is given to uni-and multi-axial textiles and canvases made of glass fibers and carbon fibers. In the case of large components that have fiber reinforcement, it is preferable that the components have been designed with the reinforcement materials of fibers. Particular preference is given to established uni and multiaxial fiberglass canvases. Blade covers for wind turbines are preferably designed with relaxed fiberglass cloths.

The molded parts are preferably produced by the process of the invention, providing an appropriate mold, introducing the mixture of the invention into said mold, and curing the material to completion only after complete filling of the mold. In the process of the invention it is preferable that the mixture of the invention is introduced into the appropriate mold by means of the infusion technology. In the present, vacuum is applied to the molding part. Said vacuum sucks the mixture of the invention in the mold at temperatures below the curing temperature of appearance in such a way that the viscosity remains almost unchanged during the loading process and all regions of the molding part are filled by the mixture before it is hardened. The complete hardening of the mixture is then carried out in the molding. Other sources of heat can be applied externally to achieve complete hardening. Figure 1 shows the Wohler plots (voltage amplitude S in MPa as axis y against the number of load cycles N as axis x, with logarithmic scale) for the cured epoxy resins comprising the mixtures of comparative example 7 (+) and the examples of the invention 2 (·), 3 (A), and 5 (-) · Eg emplos: The examples below are provided to illustrate the present invention, but the examples serve only to illustrate certain aspects of the invention and should certainly be considered not to restrict the scope of the invention.

The components of the epoxy resin a) and the hardening components b) for the examples of the invention and the comparative examples were gathered according to the data presented in Tables 1 and 2 The substances used were the following: Bisphenol A bisglycidyl ether (DGEBA, Epilox ® A18-00 from LEUNA-Harze GmbH, PEE = 180), bis-1,4-di-butanediol ether (BDGE, Epilox ® P13-21 from LEUNA-Harze GmbH), ether 1, β- hexanediol bisglycidyl (HDGE, Epilox © P13-20 of LEUNA-Harze GmbH), glycidyl alkyl ether of C12-C14 (AGE C12-C14, Epilox® P13-18 of LEUNA-Harze GmbH), propylene carbonate (PC, from BASF SE), polyetheramine 0230 (D230, Baxxodur CE ® 301 from BASF SE), polyetheramine XT J 568 (XT J568, Jeffamine ® XT J 568 from Huntsman), isophorone diamine (PAI, Baxxodur ® CE 201 from BASF SE), mixed of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1, 3-diamine (DACH, Baxxodur® ECX 210 from BASF SE), tetramethylguanidine (TG, from Lance), 2,4,6-tris (dimethylaminomethyl) phenol (DMP-30, from Sigma-Aldrich), and 1,4-diazabicyclo [2.2.2] octane (DABCO, from Sig-RNA-Aldrich).

The respective epoxy resin components a) and hardener components b) were mixed in a proportion such as to give the ratio indicated in Table 3 for the amine equivalents of hardener b) to equivalents of the total sum of epoxy resin, reactive diluent , and cyclic carbonate of epoxy resin component a).

For the mixtures of these examples, the initial viscosity at 25 ° C and the time necessary to reach a viscosity of 1000 mPa * s at 40 ° C (from compliance with DIN 16 945). The results recorded are shown in table 3.

For example comparative 3 and examples of the invention 3, 5, and 8, the composite work pieces comprising PVC foam (Divinycell H60 from DIAB) and the corresponding mixture were produced and cured at 70 ° C for 15 hours . The discoloration of the PVC foam in the vicinity of the mixture was evaluated visually and evaluated on a scale of 1 (no perceptible discoloration) to 5 (very dark discoloration). The results are collected again in table 3.

The mixtures of the examples were cured at 70 ° C for 15 hours. The heat deformation temperature (HDT), the tensile strength, the tensile modulus, the tensile strain at break, the flexural strength, and the flexural modulus were determined for cured epoxy resins comprising mixtures, in accordance with ISO 75 A, ISO 527, and ISO 178. The results of the measurements are shown in Table 4. For example, comparative 7 and examples of the invention 2, 6, and 8, the Fatigue resistance was determined as a measure of dynamic stability. For this purpose, the test elements with dimensions of 230 mm x 32 mm x 2.5 mm are produced from the respective mixtures, using a biaxial canvas (fiberglass) at 70 ° C with the Cured for 15 hours. The test elements were exposed to a single stage of long-term vibration in a voltage-pressure threshold test (sinusoidal load, R = -1, test frequency: 1.5 to 2 Hz, test direction: +/- 45 °, test temperature 23 ° C, relative humidity: 50%). A measurement was made of the number of load cycles until the test element broke, for predetermined voltage amplitudes. The measurement values and the resulting characteristic lines (ohler curve, voltage amplitude S in MPa as axis y against the number of load cycles N as axis x) are shown in Figure 1. Examples of the invention 2, 6 and 8 show an increase in fatigue resistance significantly compared to comparative example 7.

Table 1: Constitutions in parts by weight of epoxy resin component a) BDGE: Bisgenyldiol 1,4-butanediol ether HDGE: bis-glycididyl 1,6-hexanediol ether, C12-C14 AGE: C 14 -C 12 alkyl glycidyl ether Table 2: Constitutions in parts by weight of hardener component b) Table 3: Mixtures and their properties N-equiv. : amine equivalents, per epoxy / carbonate equivalent: Vise. Viscosity at 25 ° C in mPa * s T (1000 MPa * s): Time in min up to 1000 mPa * s reaches 40 ° C PVC decol. The discoloration of PVC foam in contact with the mixture during hardening: 1: none; 2: very light, 3: light; 4: dark; 5: very dark Table 3 shows that the blends of the invention are comparable in terms of viscosity and reactivity with standard blends that are used in the production of moldings for rotor blades for wind turbines.

Table 4: Cured epoxy resins Tension s: Resistance to tension in MPa; Voltage M: The voltage module in MPa; Stress s. to. b .: Deformation by stress at break in%; Flexion s: Resistance to bending in MPa. Flexural strength m: The modulus of flexion in%; HDT: Heat deflection temperature in ° C Table 4 shows that the cured epoxy resins of the invention show a higher level of mechanical properties and at the same time its HDT is above 70 ° C.

Claims (21)

1. - A mixture comprising to. an epoxy resin component comprising a) from 75 to 97 parts by weight, based on the epoxy resin component a), of one or more epoxy resins selected from the group of aromatic epoxy resins and / or cycloaliphatic epoxy resins, and a2) from 3 to 18 parts by weight, based on the epoxy resin component a), of one or more cyclic carbonates selected from the group of cyclic carbonates having from 1 to 10 carbon atoms, and a3) from 0 to 15 parts by weight, based on the epoxy resin component a), of one or more reactive diluents, wherein the parts by weight of components a) to a3) always give a total of 100, and b. a hardener comprising bl) from 10 to 79 parts by weight, based on hardener b), of one or more polyalkoxypolyamines, and b2) from 20 to 89 parts by weight, based on hardener b), of one or more other amines selected from the group of aromatic, arylaliphatic, cycloaliphatic, heterocyclic and aliphatic polyamines having at least 3 carbon atoms and at least 4 Reactive NH functions in primary and / or secondary amino groups, and b3) from 0.5 to 30 parts by weight, based on hardener b), of one or more catalysts selected from the group of tertiary amines, imidazoles, imidazolines, guanidines having less than 3 carbon atoms and / or less than 4 functions Reactive NH in amino groups, secondary amines having less than 4 reactive NH functions, substituted ureas, guanamines and ketimines, where the parts by weight of the components bl) to b3) always give a total of 100, wherein the ratio of amino equivalents of the hardener b) the equivalent of the total epoxy resin and cyclic epoxy carbonate in a resin component used is in the range of 0.3 to 0.9, wherein the reactive diluents a3) are those selected from the group of 1,4-bis-butynediol ether, bis-1,6-hexanediol bisglycidyl ether, glycidyl neodecanoate, glycidyl versatate, 2-ethylhexyl glycidyl ether, glycidyl ether Cs-Cio, C12-C14 alkyl glycidyl ether, C13-C15 alkyl glycidyl ether, p-tert-butyl glycidyl ether, butyl glycidyl ether, nonylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, phenyl ether glycidyl, o-cresyl glycidyl ether, polyoxypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether (TMP), glyceryl triglycidyl ether, triglycidyl paraaminophenol (TGPAP), divinyl benzyl dioxide and dicyclopentadiene diepoxide.

2. - The mixture according to claim 1, wherein the epoxy resins a) are selected from the group of bisphenol A bisglycidyl ether and bisphenol F bisglycidyl ether.

3. - The mixture according to claim 1 or 2, wherein the one or more cyclic carbonates a2) are propylene carbonate and / or ethylene carbonate.

4. - The mixture according to any of claims 1 to 3, wherein one or more reactive diluents a3) are selected from the group of bis-1,4-butanediol bisglycidyl ether, bis-1,6-hexanediol bisglycidyl ether, alkyl glycidyl ether of C12-C14, C13-C15 alkyl glycidyl ether and trimethylolpropane triglycidyl ether.

5. - The mixture according to any of claims 1 to 4, wherein the one or more reactive diluents a3) are those selected from the group of 1,4-butanediol bisglycidyl ether, 1,6-hexanediol bisglycidyl ether, glycidyl ether of C12-C14 alkyl, C13-C15 alkyl glycidyl ether.

6. - The mixture according to any of claims 1 to 5, wherein the one or more polyalkoxypolyamines bl) are those selected from the group of Polyetheramine D230, Polyetheramine D 400, Polyetheramine T 403, Polyetheramine T 5000 and Jeffamine ® XT J-568.

7. The mixture according to any of claims 1 to 6, wherein one or more other amines b2) are isophoronediamine (IPDA) and / or a mixture of 4-methylcyclohexane-1,3-diamine and 2-methylcyclohexane-1, 3. -diamine (MDACH).

8. - The mixture according to any of claims 1 to 7, wherein the mixture also comprises reinforcing fibers.

9. - The mixture according to any of claims 1 to 8, wherein one or more cyclic carbonates a2) comprise from 6 to 18 parts by weight, based on the epoxy resin component a).

10. - The mixture according to any of claims 1 to 9, wherein one or more catalysts b3) are selected from the group of tertiary amines and guanidines having less than 3 carbon atoms and / or less than 4 reactive NH functions in amino groups.

11. - The mixture according to any of claims 1 to 9, wherein one or more catalysts b3) are selected from the group of tertiary amines.

12. - The mixture according to any of claims 1 to 9, wherein one or more catalysts b3) are selected from the group of guanidines having less than 3 carbon atoms and / or less than 4 reactive NH functions on amino groups.

13. - The mixture according to any of claims 1 to 9, wherein one or more catalysts b3) are those selected from the group of tetramethylguanidine (TMG), 2,4,6-tris (dimethylaminomethyl) phenol (DP 30) and 1,4-diazabicyclo [2.2.2} octane (DABCO).

14. - The mixture according to any of claims 1 to 9, wherein one or more catalysts b3) are selected from the group of 2,4,6-tris (dimethylaminomethyl) phenol (DMP 30) and 1,4-diazabicyclo [2.2 0.2] octane (DABCO).

15. - The mixture according to any of claims 1 to 9, wherein the catalyst b3) is tetramethylguanidine (TMG).

16. - The mixture according to any of claims 1 to 13, wherein the one or more catalysts b3) constitute 0.5 to 7 parts by weight, based on hardener b).

17. - The mixture according to any of claims 1 to 9, wherein the one or more catalysts b3) constitute 0.5 to 7 parts by weight, based on hardener b), and are selected from the group of 2,4,6 -tris (dimethylaminomethyl) phenol (DMP 30) and 1,4-diazabicyclo [2.2.2] octane (DABCO).

18. - The mixture according to any of claims 1 to 9, wherein catalyst b3) makes 0.5 to 7 parts by weight, based on hardener b), and is 1, -diazabicyclo [2.2.2] octane (DABCO) ).

19. - A process for producing the mixture according to any of claims 1 to 18, wherein the epoxy resin component a) and the hardener b) are mixed at temperatures below the initial cure temperature.

20. - A process for producing a cured epoxy resin, wherein the mixture according to one of claims 1 to 18 is cured at a temperature greater than or equal to the curing start temperature.

21. - A cured epoxy resin obtainable by curing the mixture according to any of claims 1 to 18 at a temperature greater than or equal to the appearance cure temperature.