CH672494A5 - - Google Patents

Description

DESCRIPTION The invention relates to storage-stable, heat-curable material mixtures which contain certain difunctional and polyfunctional epoxy resins, phenolic hardeners, accelerators and certain thermoplastics, and their use for the production of shaped articles, in particular prepregs for fiber-reinforced composites and adhesive films.

A variety of curable epoxy resin mixtures, which include also contain phenolic hardeners is known. For example, JP-OS 76/129 498 substance mixtures containing polyfunctional epoxy resins, phenolic hardeners and accelerators and 5 their use for the production of prepregs for special electrical insulating materials. No. 4,322,456 discloses mixtures of epoxy resins, phenolic hardeners and accelerators, the functionality of the epoxy resins and / or the hardeners preferably being greater than 2, which are suitable for the production of i-curable coatings, particularly as powder coatings. No. 4,288,565 describes mixtures of epoxy resins with high and low epoxy equivalent weight and phenolic hardeners, which are at least 30% compounds with 3 or more hydroxyl groups per molecule.

i5 The present invention relates to storage-stable, heat-curable substance mixtures according to claim 1.

The mixtures according to the invention are suitable for the production of shaped articles, prepregs and adhesive films, and the cured products are distinguished by excellent thermal and mechanical properties, in particular by high heat resistance, excellent fracture toughness, bending and impact resistance and very high ductility out.

The mixtures also have excellent processing properties, such as e.g. a high degree of homogeneity, a long pot life (“pot life”) and a favorable stickiness (“tack”), which is retained even after long storage at room temperature.

After curing, the mixtures of substances according to the invention result in crosslinked polymers with thermoplastic-like properties (high ductility, fracture and impact strength) without having to accept the difficulties encountered when processing high-molecular thermoplastics because of their very high viscosity. The 35 mixtures according to the invention have a relatively low viscosity and can be processed without problems at low temperatures (120 to 200 ° C.).

Suitable epoxy resins (a) and (b) for the present mixtures are all those which have a functionality of 40 at least 3 or 2-2.5 and which are cured with diphenols (c) in the presence of accelerators (d) can be.

Epoxy resins with a functionality of 3, for example, are understood to mean those resins which have an average of 3 epoxy 45 groups per molecule.

Suitable as epoxy resins (a) and (b) are e.g. Di- or poly-glycidyl ethers of cycloaliphatic polyols, such as 2,2-bis (4'-hydroxycyclohexyl) propane, di- or polyglycidyl ethers of polyhydric phenols, such as resorcinol, bis (4'-hydroxyphenyl) methane, so (bisphenol F), 2 , 2-bis (4'-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4'-hydroxy-3 ', 5'-dibromophenyl) propane, 1,1,2,2-tetra-kis (4'-hydroxyphenyl) ethane, or condensation products of phenols with formaldehyde, such as phenol novolaks and cresol novolaks; further di- or poly (ß-methylglycidyl) ether of the above 55 polyalcohols and polyphenols;

Polyglycidyl esters and poly (β-methylglycidyl) esters of polyvalent carboxylic acids, such as phthalic acid, terephthalic acid, tetra-hydrophthalic acid and hexahydrophthalic acid;

Glycidyl derivatives of aminophenols, e.g. Triglycidyl-60 p-aminophenol;

N-glycidyl derivatives of amines, amides and heterocyclic nitrogen bases, such as N, N-diglycidylaniline, N, N-diglycidyl-toluidine, N, N, N ', N'-tetraglycidyl-bis (4-aminophenyl) methane, triglycidyl isocyanurate, N, N-diglyridyl-N, N'-ethylene urea, 65 N, N'-diglycidyl-5,5-dimethylhydantoin, N, N'-diglycidyl-5-iso-propylhydantoin, N, N'-diglycidyl-5,5-dimethyl -6-isopropyl-5,6-dihydrouracil;

Multifunctional epoxy resins, such as those in EP 205 409

and EP 204 659 described 2,6-disubstituted 4-epoxypropylphenyl glycidyl ether and their adducts;

Bisphenols substituted with two glycidyloxy and 2,3-epoxypropyl groups, e.g. the 2,2-bis (3'-epoxypropyl-4'-epoxypropylphenyl) propane described in GB 828 364;

Glycidyl derivatives of tetramethylol-substituted cyclohexanols, cyclohexanones, cyclopentanols and cyclopentanones, such as the compounds described in US Pat. No. 4,549,008;

Glycidyloxy-substituted benzophenones and glycidyloxydi-ketones, such as the compounds described in US 4,649,181.

In general, mixtures of two or more epoxy resins can also be used as component (a) and / or as component (b) in the compositions according to the invention.

Particularly suitable as epoxy resins (a) and (b) are compounds which have an epoxy content of 5-11 equivalents / kg and which are glycidyl ethers, glycidyl esters or N-glycidyl derivatives of a cycloaliphatic, an aromatic or heterocyclic compound. Particularly preferred epoxy resins (a) and (b) are epoxynovolaks or glycidyl derivatives of a bisphenol, a hydantoin or a tetramethylolcyclohexane.

Particularly suitable epoxy resin (a) are epoxiphenolno-volatile or glycidyl derivatives of hydantoins or tetramethylolcyclohexanes. They preferably have a functionality of 3 to 4. Epoxy-phenol novolaks or glycidyl derivatives of bisphenol A or bisphenol F are particularly suitable as epoxy resin (b). They preferably have a functionality of 2 to 2.2.

Suitable diphenols (c) are e.g. mononuclear and multinuclear dihydroxyaromatic compounds which may contain condensed benzene rings. Compounds of the formulas I or II are particularly suitable

.Oh

J \ —T — J (T) ^ ^ -R (II),

X / 1 \ X w \ ^ /

/ «Ss * • = ♦ \ is»

H0 0H ta where T is the direct bond, methylene, isopropylidene, O, S, CO or S02 and R is hydrogen or Ci-GrAlkyl, dihydroxynaphthalene or mixtures of these compounds. Preferred compounds of the formula I are those in which the hydroxyl groups are bonded in the 4,4'-position.

Particularly preferred diphenols (c) are bisphenol A, bisphenol F, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 2,6-dihydroxytoluene, 2,6-dihydroxynaphthalene or 2,7-dihydroxynaphthalene.

A mixture of 2,6-dihydroxytoluene and 2,7-dihydroxynaphthalene is particularly suitable as a phenolic hardener. Particularly good results are achieved if equal amounts by weight of these compounds are mixed in the melt at about 1800 ° C., the product obtained after the melt solidifies is ground to a fine powder and this is then used as a hardener.

If appropriate, the substance mixtures according to the invention can, as hardeners, in addition to the diphenols (c) also a certain amount of one or more tri- or polyphenols, such as e.g. 2,4,6-Tris [2 '- (p-hydroxyphenyl) -2'-propyl] benzene (“Tris-TC” from Mitsui Petrochemical). In general, however, at most 30% of the phenolic hydroxyl groups should come from a tri- or polyphenol, and the rest of the hydroxyl groups should belong to a diphenol. Phenol or cresol novolaks are generally not suitable as phenolic hardeners for the mixtures according to the invention. It goes without saying that when both diphenols and tri- or poly-phenols are used, the amount of the total phenolic hardener (c) is chosen such that a total of 0.7-1.2 hydroxyl equivalents of the

672 494

phenols used per epoxy equivalent of the epoxy resins used are contained in the mixture according to the invention.

Suitable accelerators (d) of the curable substance mixtures are all those known to the person skilled in the art for accelerating the crosslinking reaction of epoxy resins with phenolic hardeners, such as, for. B. tertiary amines, their salts or quaternary ammonium compounds such as tetramethylammonium chloride, phosphonium salts, alkali metal alcoholates, such as e.g. Sodium hexanetriolate, Lewis acids e.g. BF3 or SnCl.4, and nitrogen-containing heterocycles such as pyridines, imidazoles and their derivatives. Imidazoles and N-acylimidazoles (imidazolides) are particularly suitable as accelerators (d).

Examples of suitable imidazoles are compounds of the formula III

• SS «

"O (III),

h wherein R1, R2 and R3 independently of one another are hydrogen, Q-Ci2-alkyl, C5-Cio-cycloalkyl or Cö-Cio-aryl. In particular, 2-methyl, 2-ethyl, 2-phenyl and 2-ethyl-4-methyl-imidazole are preferred.

Suitable N-acylimidazoles (imidazolides) are e.g. the compounds described in US 4,436,892, US 4,587,311 and JP-OS 74/7599. Compounds of the formula IV are particularly suitable

? —Îj / \ (IV),

r7 / - \ 8 \ S h wherein R1 to R3 have the meaning given above and R4 to R8 are independently hydrogen, Ci-Ci2-alkyl, halogen, nitro or trifluoromethyl. Examples of suitable imidazolides are 1- (2 ', 4', 6'-trimethylbenzene) -2-ethylimidazole, 1- (2 ', 6'-dichlorobenzoyl) -2-methylimidazole, 1 - (2', 4 ', 6' -Trimethyl-benzene) -2-methylimidazole and 1- (2 ', 4', 6'-trimethylbenzene) -2-phenylimidazole.

As thermoplastics (e), all those known polymers can be used in the curable material mixtures according to the invention which have a sufficiently high glass transition temperature, i.e. Have> 180 ° C and are miscible with the epoxy resin hardener system according to the invention. On the basis of their properties, polyimides, polyetherimides, polyamideimides, polysulfones or polyether sulfones are particularly suitable as thermoplastics. Thermoplastics with a glass transition temperature of 180 to 350, in particular of 190 to 250 ° C. are particularly preferred.

If a polysulfone is used as the thermoplastic (s), e.g. Connections with the repeating unit of the formula

-A-S02-

wherein A is a divalent aromatic group which is optionally interrupted by ether oxygen atoms and / or divalent aliphatic groups.

The polysulfones to be used can be e.g. can be obtained by either (a) a sulfonyl halide of the formula IHLA4SO2X or (b) a mixture of a disulfonyl halide of the formula XS02AiS02X with a sulfo

3rd

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

672 494

4th

nyl halide-free compound of the formula HA2H, in which Ai and A2 are identical or different and each represent a divalent aromatic group which may be interrupted by ether oxygen atoms and / or divalent aliphatic groups and X represents a chlorine or bromine atom, in an inert solvent in the presence of a Lewis acid -Catalyst heated. The polysulfones produced by process (a) contain the repeating unit in which A3 and A4 are divalent alylene groups, in particular phenyl groups, which can be substituted by chlorine or C 1 -C 4 -alkyl, for example methyl groups. Such polysulfones are obtained in a manner known per se by reaction of a dialkali metal salt of a dihydric phenol of the formula HOA3OH with a bis (monochloraiyl) sulfone of the formula ClAtSC ^ AtCl in dimethyl sulfoxide. More preferred polysulfone resins are those with a repeating unit of the formula

-AI-S02-,

10th

-OAj-Y-AsOAe-SOz-Ae-

whereas the polysulfones produced by process (b) are the repeating unit

—Ai — SO 2 — A.2 — SO 2—

exhibit.

Polysulfone resins which are preferably used in the compositions according to the invention are those which have ether groups in the repeating unit but are free from side-stable hydroxyl groups. These are especially polysulfones with a recurring unit of the formula

—OA3OA4SO2A4—,

wherein A5 and A6 each have a chlorine or C 1 -C 4 alkyl group, e.g. Methyl groups, substituted phenylene group and Y is a carbon-carbon bond, the 15 -SO2 or an aliphatic hydrocarbon group, especially one with no more than four carbon atoms such as e.g. those of the formula

? H3

-CH2- or

20th

mean.

Thermoplastic polysulfone resins with repeating units of the formula V are particularly preferred

<() • • 2 «« SS *

(V),

Jn where n preferably has an average value of 50-120.

Particularly advantageous polysulfones are e.g. the compounds available from Union Carbide Corporation, e.g. "Polysulfone Udel PI800", which according to the manufacturer has a melting point in the range of 350-370 0 C, a heat resistance (ASTM specification D648) of 175 ° C and an average of 50-80 recurring units of the formula V per molecule contains, with a molecular weight range of approximately 22,000-35,000 can be assumed.

Also suitable is a similar substance available from Union Carbide Corporation under the name “Polysulfone P2300”; According to the manufacturer, this has a molecular weight range of 30,000-50,000, where it can be assumed that the substance contains on average approximately 68-113 recurring units of the formula V per molecule, and one at Union Carbide Corporation under the name “Polysulfone P3500 »available similar substance; according to the manufacturer, this has a molecular weight range which is between that of "Polysulfone Udel PI 800" and that of Polysulfone P2300 "; the molecular weight is about 35,000.

According to the invention, mixtures of two or more thermoplastics can also be used as component (e).

Particularly suitable as thermoplastics (e) are polyimides, such as

Polyimides with phenylindane units, such as those e.g. are described in US 3,856,752 and EP-A 92 524,

- Homo- and copolyimides from at least one aromatic tetracarboxylic acid and at least one aromatic diamine, such as e.g. in US 4,629,777 and

- Homo- and copolyimides, e.g. in EP-A 162 017, EP-A 181 837 and US 4,629,685.

Preferred thermoplastics (e) are also polyetherimides, e.g. the products from General Electric offered under the name Ultem® (e.g. Ultem® 1000). Other preferred thermoplastics are polyether sulfones, e.g. Victrex PES 35 100 Pder ICI or Udel P 1800 from Union Carbide.

Suitable polyamideimides are, for example, the compounds described in US Pat. Nos. 3,894,114, 3,948,835, 3,926,911 and 3,950,408.

The 40 components (a) to (e) used in the mixtures according to the invention are all known compounds and can be prepared in a known manner.

Particularly preferred curable mixtures according to the invention are those comprising 15 to 50 parts by weight of the epoxy resin (a), 85 to 50 parts by weight of the epoxy resin (b), an amount of the 45 diphenol (c) which are 0.8-1.1, preferably 0.9- 1.0, hydroxyl equivalent of diphenol per epoxy equivalent of resins (a) and (b), 0.1-1% by weight of accelerator (d) based on the amount of (a) and (b) and 20 -110, preferably 30-70, parts by weight of the thermoplastic (e) based on 100 parts by weight of components (a) to (c).

The mixtures according to the invention can be provided by thoroughly mixing or dissolving all of the components together, the individual components being able to be added in a different order. The thermoplastic 55 can e.g. be dissolved in the epoxy resin and in the phenolic hardener while heating, and after cooling the accelerator and, if appropriate, further additives can be added. However, a solution of the thermoplastic in an inert solvent, such as e.g. in methylene chloride, prepare 60 and mix them with the epoxy resin hardener mixture.

The mixtures according to the invention can be used in a variety of ways and are suitable, for example, as casting resins, laminating or impregnating resins, molding compositions, sealing compositions, embedding and insulating compositions for electrical engineering and preferably as adhesives and as matrix resins for composites, in particular for the production of fiber-reinforced materials Plastics.

If desired, in particular when modifiers are also used, the mixtures according to the invention can

5

672 494

see in an organic solvent such as toluene, xylene, methyl ethyl ketone, methylene chloride or a similar solvent or solvent mixture common in the paint industry. Such solutions are particularly suitable as impregnating agents or coating agents.

The hardenable mixtures according to the invention can furthermore be mixed in any phase with conventional modifiers, such as extenders, fillers and reinforcing agents, pigments, dyes, organic solvents, plasticizers, flow control agents, thixotropic agents, flame retardants or mold release agents, before the hardening. Examples of extenders, reinforcing agents, fillers and pigments which can be used in the curable mixtures according to the invention include called: liquid coumarone indene resins, textile fibers, glass fibers, asbestos fibers, boron fibers, carbon fibers, polyethylene powder, polypropylene powder, quartz powder, mineral silicates such as mica, asbestos powder, slate powder, kaolin, chalk powder, anti-montrioxide, bentone, iithopone, heavy spar , Titanium dioxide, carbon black, graphite, oxide paints, such as iron oxide, or metal powder, such as aluminum powder or iron powder. If the mixtures according to the invention are used for the production of prepregs, addition of short fibers is particularly desirable.

As a leveling agent when using the curable mixtures, especially in surface protection, one can e.g. Add silicones, liquid acyl resins, cellulose acetobutyrate, polyvinyl butyral, waxes, stea rates, etc. (some of which are also used as mold release agents). As plasticizers for the modification of the curable mixtures e.g. Dibutyl, dioctyl and dinonyl phthalate, tricresyl phosphate, trixylenyl phosphate and diphenoxyoxyethyl formal can be used.

The mixtures according to the invention are preferably cured by heating them to a temperature in the range from 120 to 250 ° C., in particular 150 to 200 ° C. You can do that

Epoxy resin bl: An epoxy phenol novolak liquid at room temperature with a functionality of 2.2 with an epoxy content of 5.7 equivalents / kg and a viscosity at 50 ° C of 1.4 Pa-s.

Epoxy resin b2: A bisphenol F diglycidyl ether with an epoxy content of 6.1 equivalents / kg and a viscosity at 25 ° C of 6.0 Pa-s.

and a glass transition temperature of 219 ° C (Ultem® 1000 from General Electric).

Polysulfone 1: Polysulfone Udel PI 800® (Union Carbide Corporation) with a melting point in the range of 350-370 ° C, a heat resistance (according to ASTM D 648) of 175 ° C,

Cure in a known manner also in two or more stages, the first curing stage being carried out at a low temperature and the post-curing at a higher temperature.

If desired, the curable mixtures can be used to reduce the viscosity of active thinners, e.g. Add neopen tylglycol, butanediol or hexanediol diglycidyl ether.

The present invention also relates to the use of the mixtures according to the invention for the production of hardened moldings, and the use for the production of prepregs for fiber-reinforced composites or for the production of adhesive films. The prepregs and the adhesive films can be produced in a manner known per se, e.g. in the impregnation process in the presence of one of the solvents mentioned above, a halogenated solvent, e.g. 15 methylene chloride, or in the so-called "hot melt" process.

The molding materials according to the invention are generally distinguished by high glass transition temperatures with high mechanical strengths, and in particular by excellent fracture toughness, bending and impact resistance, and very high ductility.

The following examples explain the invention in more detail.

Components (a) - (e) used in the following examples are as follows:

Epoxy resin al: An epoxy phenol novolak with a functionality 25 of 3.6 with an epoxy content of 5.6 equivalents / kg and a viscosity at 50 ° C of about 40 Pa • s.

Epoxy resin a2: tetraglycidyl ether of 2,2,6,6-tetramethylol-cyclohexanol (produced according to Example 2 of US Pat. No. 4,549,008) with an epoxy equivalent weight of 129.

30 Epoxy resin a3: A triglycidyl-bis-hydatoin of formula VI with an epoxy content of 5.6 equivalents / kg and a viscosity at 80 ° C of about 13 ÎPa-s

(VI)

Polyimide 1: A polyimide with phenylindane units with a glass transition temperature of 305 ° C. and an average molecular weight of about 65,000 (Matrimid® 5218, Ciba-Geigy).

Polyetherimide 1: A polyetherimide with repeating units of the formula

J n a glass transition temperature of 200 ° C and a molecular weight range of about 22,000-35,000.

Example 1:

a) 15 g of epoxy resin al and 85 g of epoxy resin are bl

H.c f> 0

, ch3

CH-CHz-N ^ ^ N-CHz-CH-CHZ- ^ N-CH2-qi-CH2

6

SH2 ÏH

*

ö

\

: Hz

-K i »n / \

v «» —.n——

\ _ / ^ / \ /

r »SC»

çh3

ch3

s s \ /

/ ^ /

II I •> •

\

• '•

I II

672 494

120 ° C mixed. At this temperature, 17.7 g of 2,6-dihydroxytoluene and 17.7 g of 2,7-dihydroxynaphthalene are added and dissolved with stirring. After the mixture has cooled to 80 ° C., 0.1 g of 2-phenylimidazole is added. After cooling to room temperature, a solution of 81.2 g of polyimide 1 in 82 g of methylene chloride is added to the mixture and the mixture is stirred well until a homogeneous mixture is formed. With the mixture, an Elm of 0.1 mm thickness is poured onto siliconized paper using a doctor blade and the solvent is evaporated at room temperature. Several strips of 30 x 30 mm are stacked on top of each other, pressed to a 1 mm thick molded body at 180 ° C and hardened at 180 ° C for 1 h. The molded body has a Tg (measured by means of thermomechanical analysis) of 142 ° C with secondary conversion at 160 ° C.

b) If repetition of Example la), but using 135.4 g of polyimide 1 as a thermoplastic, a Tg of 153 and 182 ° C. is measured after curing.

Example 2:

If Example la is repeated, but using 44.7 g of polysulfone 1 as the thermoplastic, a Tg of 164 ° C. with pre-softening at 96 ° C. is measured after curing.

Example 3:

a) 35 g of epoxy resin a2 and 65 g of epoxy resin b2 are mixed at 120 ° C. with 20.5 g of 2,6-dihydroxytoluene and 20.5 g of 2,7-dihydroxynaphthalene. 0.1 g of 2-phenylimidazole is added to the mixture, it is cooled to room temperature and then, as described in Example 1, 84.5 g of polyimide 1 in methylene chloride are added and processed. After curing, a Tg of 194 ° C with weak pre-softening is measured at 104 ° C.

b) When using 60.4 g of polyimide 1 and otherwise the same composition and processing as in a), a film-shaped body with a Tg of 210 and 105 0 C is obtained. With part of the film, 2 Al plates are glued together at 180 ° C and post-cured at 200 ° C for 1 h. The cured resin has a fracture toughness (GiC) of 794 J / m 2, measured using the double torsion test according to "Journal of Materials Science, 10, 1334 (1975) and 14.776 (1979)". Two extrudal aluminum sheets 050 AlMgSi 0.5) measuring 200 x 20 x 5 mm, which have been treated with chromosulphuric acid, are glued to the hardenable mixture and the glue is hardened using light pressure. With this measuring method, crack propagation is measured in the bond, i.e. the breaking energy in J / m2 is calculated from the maximum load for crack propagation.

Example 4:

50 g of epoxy resin a3 and 30 g of epoxy resin b2 are mixed and processed with 19 g of 2,6-dihydroxytoluene, 19 g of 2,7-dihydroxynaphthalene, 0.1 g of 2-phenylimidazole and 138 g of polyetherimide 1, as described in Example 15. After curing, a Tg of 188 ° C with a low pre-softening at 100 ° C is measured.

Example 5:

Example 3a is repeated by using 59.2 g of 4,4'-dihydroxydiphenyl ether as the hardener instead of the 2,6-dihydroxytoluene / 2,7-dihydroxynaphthalene mixture used therein. The hardened mixture has a Tg of 192 ° C. with little pre-softening at 80 ° C.

15

Example 6:

a) 35 g epoxy resin a2.65 g epoxy resin b2.22 g 2,6-dihydroxytoluene, 22 g 2,7-dihydroxynaphthalene, 0.1 g l- (2 ', 4', 6'-tri-methylbenzene) -2 -phenylimidazole and 96 g of polyimide 1

20 processed according to Example 3a. After curing for 1 hour at 180 ° C. and 1 hour at 200 ° C., a Tg of 212 ° C. is measured.

b) If the test is repeated using 71 g of polyimide 1, a Tg of 2220 ° C. (slight pre-softening

25 at 100 ° C) and a fracture toughness GiC (double torsion test) of 976 J / m2 measured.

Example 7:

a) 15 g epoxy resin al, 85 g epoxy resin bl, 17.7 g 2,6-dihy-30-hydroxytoluene, 17.7 g 2,7-dihydroxynaphthalene, and a solution of 0.1 g 2-phenylimidazole and 44.7 g of polysulfone 1 are processed as described in Example 1 and cured at 180 ° C. for 2 hours. The hardened molded body has a Tg of 164 ° C with pre-softening at 96 ° C.

35 b) If the experiment is repeated using 80.4 g of polyimide 1 instead of the polysulfone, the hardened molded body has a Tg of 142 ° C.

Example 8:

40 100 g of a mixture consisting of 35 parts by weight of epoxy resin al, 65 parts by weight of epoxy resin bl, 20.5 parts by weight of 2,6-dihydroxytoluene, 20.5 parts by weight of 2,7-dihydroxynaphthalene, 0.2 parts by weight of l- (2 ', 4', 6'-TrimethylbenzoI) -2-phenylimidazole and 80.4 g of polymide 1 are processed and cured as described in Example 1 45. The hardened molded body has a Tg of 194 ° C with little pre-softening at 101 ° C.

Claims (11)

672 494 PATENT CLAIMS 1. Storage-stable, heat-curable mixture comprising a) 10-60 parts by weight of at least one epoxy resin with a functionality of at least 3, b) 90-40 parts by weight of at least one epoxy resin with a functionality of 2-2.5, c) at least one diphenol, the amount of the diphenol being chosen such that it is 0.7-1.2 hydroxyl equivalents of the diphenol (c) per epoxy equivalent of the epoxy resins (a), d) 0.05-5% by weight, based on the epoxy resins (a) and (b), of an accelerator, and e) 10-120 parts by weight, based on 100 parts by weight of components (a) to (c), at least a thermoplastic with a glass transition temperature of at least 180 ° C. 2. Mixture according to claim 1, wherein the epoxy resins (a) and (b) have an epoxy content of 5-11 equivalents / kg and are glycidyl ethers, glycidyl esters or N-glycidyl derivatives of a cycloaliphatic, an aromatic or a heterocyclic compound. 3. Mixture according to claim 1, wherein the diphenol (c) is a compound of formulas I or II • Sy-. X ./ Vs. (I) (TT) /•.=/ \ =. \ W E (II> 1 H ° 0.1 tn where T is the direct bond, methylene, isopropylidene, O, S, CO or S02 and R is hydrogen or C1-C4-alkyl, a dihydroxynaphthalene or a mixture of these compounds 4. Mixture according to claim 1, wherein the diphenol (c) bisphenol A, bisphenol F, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 2,6-dihydroxytoluene, 2,6-dihydroxynaphthalene or 2.7 -Dihydroxynaphthalene is. 5. A mixture according to claim 1, wherein the accelerator (d) is an imidazole or an N-acylimidazole. 6. A mixture according to claim 1, wherein the thermoplastic (e) is a polyimide, a polyetherimide, a polyamideimide, a polysulfone or a polyethersulfone. 7. Mixture according to claim 1, wherein the thermoplastic (e) has a glass transition temperature of 180 to 350, in particular from 190 to 250 ° chat. 8. Mixture according to claim 1 containing 15 to 50 parts by weight of the epoxy resin (a), 85 to 50 parts by weight of the epoxy resin (b), an amount of the diphenol (c) which is 0.8-1.1, preferably 0.9-1 , 0, hydroxyl equivalents of diphenol per epoxide equivalent of resins (a) and (b) corresponds to, 0.1-1% by weight of accelerator (d) based on the amount of (a) and (b) and 20-110, preferably 30-70 parts by weight of the thermoplastic (e) based on 100 parts by weight of components (a) to (c). 9. Use of the mixture according to claim 1 for the production of hardened moldings. 10. Use of the mixture according to claim 1 for the production of prepregs for fiber-reinforced composites. 11. Use of the mixture according to claim 1 for the production of adhesive films.