Note: Descriptions are shown in the official language in which they were submitted.
1 337088
~ 1 --
K-17179/+
Curable epoxy resin mixture
The invention relates to a curable mixture containing at least one
tetraglycidyl compound of a dinuclear diamine, preferably of diamino-
diphenylmethane, bis(3,5-diethyl-4-aminophenyl)methane, preferably
together with another alkyl- or halogen-substituted dinuclear diamine or
with a particular disecondary diamine, as hardener, and also a thermo-
plastic with a glass transition temperature of at least 150C, and to its
use, especially as matrix resin for prepregs.
Substituted dinuclear diamines, for example bis(4-amino-3,5-dialkyl-
phenyl)methanes or bis(4-amino-3-chloro-5-ethylphenyl)methane, are known
as epoxy resin hardeners, for example from British patent 935 606, German
Offenlegungsschrift 23 39 237 or European patent document A-O 171 588.
The curable mixtures known hitherto have a low storage stability and are
only of limited suitability for the manufacture of prepregs, since these
rapidly lose the tackiness desired for more manageable processing.
It is further known that the properties of epoxy resin mixtures can bemodified by the addition of particular thermoplastics. For example,
European patent document A-O 108 476 discloses that, when added to
curable epoxy mixtures, polyetherimides have an advantageous effect on
the viscosity properties of the mixtures. German Offenlegungs-
schrift 26 50 019 discloses that moulded materials of greater flexibility
are obtained when polyetheramideimide resins are added to curable epoxy
resins.
It has now been found that when bis(3,5-diethyl-4-aminophenyl)methane is
used as hardener for tetraglycidyl compounds of divalent diamines, mixed
with a thermoplastic, moulded materials are obtained which have a
surprisingly high elongation and fracture toughness and a high glas
transition temperature (Tg). -
1 337088
_ - 2 -
When a mixed hardener is used, the mixtures of the invention not only
have better processing properties but also have the advantage that the
hardener does not crystallize out in the curable mixture, with the result
that the tackiness of the prepregs manufactured with the mixtures of the
invention is preserved for long periods. The mixtures of the invention
can also be used to manufacture good thin films (< 0.1 mm).
The present invention thus relates to a curable epoxy resin mixture
comprising
(a) as epoxy resin component, 50 to 100 ~0 by weight of a tetraglycidyl
compound of formula I: -
R\ /R2
(C~2~CH-CHz~-N~ --X--~ ~--N-~CH2-C~-~H2) (I)
R3/ \R4
wherein Rl, R2, R3 and R4 are each independently of the other a hydrogen
atom, a halogen atom or Cl-C4alkyl and X is a direct bond, methylene,
isopropylidene, O, CO, S or SO2, and O to 50 % by weight, based on the
tetraglycidyl compound of formula I, of a diepoxy compound or of a
polyepoxy compound differing from the compound of formula I, (b) as
hardener for the epoxy resin component, the diamine of formula II:
C~Hs /C2Hs
HzN ~ - - CHz - ~ /- - NH2 (II)
C2Hs CzH5
in an amount such that there are 0.2 to 1.1 amine hydrogen equivalents
per epoxy equivalent of epoxy resin component (a), a diamine of
formula III:
~ / Rll R7
HzN - ~ ~- - CH2 - ~ ~- - NH2 (III),
R6 / \Rl o Rl 2/ \R8
_ _ 3 _ 1 337088
wherein Rs, R6, R7 and R8 are each independently of the other C1-C4alkyl,
no more than two of the substituents Rs to R8 being ethyl, and R9, R10,
R11 and R12 are each independently of the other a hydrogen or halogen
atom, in an amount such that there is 0.0 to 0.8 amine hydrogen equi-
valent per epoxy equivalent, and a disecondary diamine of formula IV:
H~ y ~H (IV),
13 14
wherein Y is a polymethylene radical which is unsubstituted or substi-
tuted by C1-C4alkyls and contains at least 4 C atoms in the linear
polymethylene chain, and R13 and R14 are each a saturated carbocyclic
ring which is unsubstituted or substituted by C1-C4alkyls, or a ring
system containing at least 5 ring carbon atoms, in an amount such that
there is 0.0 to 0.2 amine hydrogen equivalent per epoxy equivalent, the
sum of the amine hydrogen equivalents of the diamines of formulae II,
III and IV being not greater than 1.2,
(c) 10 to 60 % by weight, based on epoxy resin component (a), of a
thermoplastic with a glass transition temperature of at least 150C, and
(d) 0 to 20 % by weight, based on epoxy resin component (a), of an amine-
or carboxyl-terminated rubber based on butadiene or butadiene-acrylo-
nitrile.
In the mixtures of the invention, epoxy resin component (a) preferablyconsists to the extent of up to 100 % by weight of a compound of
formula I. Of the compounds of formula I, the tetraglycidyl compound of
4,4'-diaminodiphenylmethane is preferred.
The compounds of formula I are known and some of them are commerciallyavailable.
The following epoxy compounds are examples of possible diepoxy or
poly-epoxy compounds which can be present to the extent of up to 50 % by
weight in the curable epoxy resin mixtures of the invention:
Polyglycidyl and poly(~-methylglycidyl) esters obtainable by reacting
compounds containing two or more carboxylic acid groups per molecule with
epichlorohydrin, glycerol dichlorohydrin or ~-methylepichlorohydrin in
1 337088
-- 4 --
the presence of alkali. Such polyglycidyl esters can be derived from
aliphatic polycarboxylic acids, e.g. oxalic acid, succinic acid, glutaric
acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid
and dimerized ~r trimerized linoleic acid, from cycloaliphatic poly-
carboxylic acids such as tetrahydrophthalic acid, 4-methyltetrahydro-
phthalic acid, hexahydrophthalic acid and 4-methylhexa-hydrophthalic
acid, or from aromatic polycarboxylic acids such as phthalic acid,
isophthalic acid and terephthalic acid.
Further examples are polyglycidyl and poly(~-methylglycidyl) ethers
obtainable by reacting compounds containing at least two free alcoholic
hydroxyl groups and/or phenolic hydroxyl groups per molecu-le with
suitable epichlorohydrins under alkaline conditions or in the presence of
acid catalysts, followed by treatment with alkali. Such ethers can be
derived from acyclic alcohols such as ethylene glycol, diethylene glycol
and higher poly(oxyethylene) glycols, propane-1,2-diol and poly(oxy-
propylene) glycols, propane-1,3-diol, butane-1,4-diol, poly(oxytetra-
methylene) glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-
triol, glycerol, 1,1,1-trimethylolpropane, pentaerythritol, sorbitol and
polyepichlorohydrins, from cycloaliphatic alcohols such as cyclo-
hexane-1,3- and -1,4-diol, bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-
hydroxycyclohexyl)propane and l,l-bis(hydroxymethyl)cyclohex-3-ene, or
from alcohols containing aromatic rings, such as N,N-bis(2-hydroxyethyl)-
aniline and p,p'-bis(2-hydroxyethylamino)diphenylmethane. They can also
be derived from mononuclear phenols such as resorcinol and hydroquinone,
and from polynuclear phenols such as bis(4-hydroxyphenyl)methane,
4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)sulfone, 1,1,2,2-tetrakis(4-
hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-di-
bromo-4-hydroxyphenyl)propane and novolaks which are in turn derived from
aldehydes such as formaldehyde, acetaldehyde, chloral and furfuraldehyde,
and from phenols such as unsubstituted phenol and phenols substituted in
the ring by chlorine atoms or alkyl groups containing up to 9 C atoms,
such as 4-chlorophenol, 2-methylphenol and 4-tert-butylphenol.
Examples of poly(N-glycidyl) compounds are compounds obtained by the
dehydrochlorination of reaction products of epichlorohydrin and amines
containing at least two amine hydrogen atoms, such as aniline, n-butyl-
~ 5 _ 1 33708~
amine and m-xylylenediamine; triglycidyl isocyanurate and N,N'-diglycidyl
derivatives of cyclic alkyleneureas such as ethyleneurea, 1,3-propylene-
urea and hydantoins like 5,5-dimethylhydantoin.
Examples of poly(S-glycidyl) compounds are the S-glycidyl derivatives of
dithiols such as ethane-1,2-dithiol and bis(4-mercaptomethylphenyl)
ether.
It is also possible to use epoxy resins in which the 1,2-epoxy groups are
bonded to different heteroatoms, e.g. the N,N,O-triglycidyl derivative of
4-aminophenol, the glycidyl ether glycidyl ester of salicylic acid,
N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethyl-hydantoin~and
2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3-yl)propane.
Said epoxy compounds are known and some of them are commercially
available.
The curable mixtures of the invention preferably contain, as
hardener (b), a mixture of the diamine of formula II and a diamine of
formula III or IV. The hardener (b) can also consist of a mixture of the
diamine of formula II, a diamine of formula III and a diamine of
formula IV, the sum of the amine hydrogen equivalents of the diamines of
formulae II, III and IV being not greater than 1.2.
In particular, the hardener (b) consists of a mixture of the diamine of
formula II and a diamine of formula III, it being preferred to use a
mixing ratio of 1:1 to 3:1.
As mentioned at the outset, the diamines of formulae II and III are
known. In formula III, Rs, R~, R7 and R8 are preferably each independent-
ly of the other methyl, ethyl, propyl or isopropyl, in particular each
independently of the other methyl or isopropyl, and R9, Rl, Rll and Rl2
are each a hydrogen atom.
1 337088
~_ -- 6 --
Examples of suitable compounds of formula III are bis( 3-methyl-4-amino-
5-ethylphenyl)methane, bis( 3-methyl-4-amino-5-isopropylphenyl)methane,
bis(3,5-diisopropyl-4-aminophenyl)methane, bis(2-chloro-3,5-diethyl-4-
aminophenyl)methane, bis( 3-ethyl-4-amino-5-sec-butylphenyl)methane and
bis(2,6-dichloro-3,5-diethyl-4-aminophenyl)methane.
An especially preferred hardener (b) is a mixture of the diamine of
formula II and a diamine of formula IV. The diamines of formula IV and
the processes for their preparation are known from German
patent 17 70 539. As diamines of formula IV, it is preferred to use those
in which Y in said formula is an unsubstituted polymethylene radical
containing 4 to 8 C atoms and R1 3 and R1 4 are each cyclopentyl or
cyclohexyl.
Examples of suitable compounds of formula IV are N,N'-di(cyclopentyl)-
hexamethylenediamine, N,N'-di(cyclohexyl)-2,2,4-trimethylhexamethylene-
diamine, N,N'-di(cyclohexyl)-2,4,4-trimethylhexamethylenediamine and, in
particular, N,N'-di(cyclohexyl)hexamethylenediamine.
Thermoplastics (c) which can be used in the curable mixtures of sub-
stances of the invention are all known polymers which have a sufficiently
high glass transition temperature (Tg), i.e. Tg > 150C, and are miscible
with the epoxy resin hardener system in question. On account of their
properties, polysulfones, polyethersulfones, polyimides or polyether-
imides are particularly suitable as thermoplastics, especially poly-
sulfones and polyetherimides. Thermoplastics with a glass transition
temperature in the range from 180 to 350C, in particular 190 to 250C,
are especially preferred for this purpose. When polyetherimides are used,
polymers with a Tg in the range from 220 to 250C are especially pre-
ferred; when polyimides are used, those with a Tg in the range from
280 to 340C are especially preferred.
Examples of suitable polysulfones used as thermoplastic (c) are compounds
containing the repeat unit of the formula
--A--SO2-- -
1 337088
_ - 7 -
wherein A is a divalent aromatic group which may be interrupted by ether
oxygen atoms and/or divalent aliphatic groups.
The polysulfones to be used can be obtained in known manner, e.g. by
heating either (1) a sulfonyl halide of the formula HAlSO2X or (2) a
mixture of a disulfonyl halide of the formula XSO2A1SO2X with a compound
of the formula HA2H which is free from sulfonyl halide, wherein Al and A2
are identical or different and are each a divalent aromatic group which
may be interrupted by ether oxygen atoms and/or divalent aliphatic
groups, and X is a chlorine or bromine atom, in an inert solvent in the
presence of a Lewis acid catalyst. The polysulfones prepared by
process (1) contain the repeat unit
--Al--SOz--,
whereas the polysulfones prepared by process (2) contain the repeat unit
- Al - SOz - Az - SOz - -
Polysulfone resins which are preferably used in the mixtures of the
invention are those which contain ether groups in the repeat unit, but
which are free from lateral hydroxyl groups. Said polysulfones are in
particular those containing a repeat unit of the formula
- OA30A4SOzA4 - ,
wherein A3 and A4 are divalent arylene groups, especially phenylene
groups, which can be substituted by chlorine or Cl-C4alkyl, for example
methyl groups. Such polysulfones are obtained in a manner known per se by
reacting a dialkali metal salt of a dihydric phenol of the formula HOA30H
with a bis(monochloroaryl) sulfone of the formula ClA4SOzA4Cl in dimethyl
sulfoxide. More preferably, the polysulfone resins used are those
containing a repeat unit of the formula
- OAs - Yl - AsOA6 - SO2 - A6 -
1 337088
21489-7779
-- 8 --
wherein As and A6 are each a phenylene group which is unsubstituted or
substituted by chlorine or C1-C4alkyl groups, e.g. methyl groups, and Y
is a carbon-carbon bond, the -SOz- group or an aliphatic hydrocarbon
group, especially one containing no more than four carbon atoms, e.g. a
hydrocarbon group of the formula
CIH3
- CH2 - or ~
H3
It is especially preferred to use thermoplastic polysulfone resins
containing repeat units of formula V:
_ C~H3 _ _ _
--¢~ SO2~ -~ (V),
.=. .=. .=. .=.
H3 -n
wherein n preferably has an average value of 50-120.
Examples of particularly advantageous polysulfones are the compounds
obtainable from the Union Carbide Corporation, such as Polysulfone
Udel P1800, which, according to the manufacturer, has a melting point in
the range from 350 to 370C, has a deflection temperature under load
(ASTM specification D648) of 175C and contains an average of
50-80 repeat units of formula V per molecule, it being possible to assume
a molecular weight range of about 22,000-35,000.
Also suitable are a similar substance obtainable from the Union CarbideCorporation under the name "Polysulfone P2300", which, according to the
manufacturer, has a molecular weight range of 30,000-50,000, from which
it can be assumed that the substance contains an average of about
68-113 repeat units of formula v per molecule, and a similar substance
obtainable from the Union Carbide Corporation under the name "Poly-
sulfone P3500", which, according to the manufacturer, has a molecular
weight range between that of Polysulfone Udel P1800 and that of
"Polysulfone P2300", the molecular weight being ca. 35,000.
_
~,:
1 337088
- 9 - 21489-7779
According to the invention, it is also possible to use mixtures of two or
more thermoplastics as component (c).
Particularly suitable as thermoplastics (c) are polyimides such as
- polyimides containing phenylindane units, e.g. those disclosed in US
patent 3 856 752 and in European patent document A 92 524, especially
those with a glass transition temperature of about 305C and an average
molecular weight of ca. 65,000, e.g. Matrimid~ 5218 from Ciba-Geigy,
- homopolyimides and copolyimides of at least one aromatic tetracar-
boxylic acid and at least one aromatic diamine, e.g. those disclosed in
US patent 4 629 777, and
- homopolyimides and copolyimides such as those disclosed -in European
patent documents A 162 017 and A 181 837 and in US patent 4 629 685.
Other preferred thermoplastics (c) are polyetherimides such as the
products commercially available from General Electric under the name
Ultem~ (e.g. Ultem~ 1000). Other preferred thermoplastics are polyether-
sulfones such as Victrex~ PES 100 P from ICI or Udel P 1800 from Union
Carbide.
Examples of suitable polyamide-imides are the compounds disclosed in
US patents 3 894 114, 3 948 835, 3 926 911 and 3 950 408.
The amine- or carboxyl-terminated rubbers based on butadiene or buta-
diene-acrylonitrile, which may be present as component (d) in the curable
mixtures of the invention, are known and are commercially available from
B.F. Goodrich under the name Hycar~, which are reactive liquid polymers.
The amine-terminated (AT) or carboxyl-terminated (CT) reactive liquid
polymers are homopolymers of butadiene (B) or copolymers of butadiene and
acrylonitrile (BN). In some of the products obtainable, additional
reactive groups, for example vinyl or carboxyl groups, are distributed
throughout the polymer chain.
For the carboxyl-terminated butadiene-acrylonitrile rubber (CTBN), for
example, the structure can be represented in simplified form as follows:
-- 10 --
~ ~37088
HOOC ~ CH2-CH=CH-CH2~ CHz-~1l) ] COOH ,
wherein x is a number from 1 to 10, preferably 2-7, y is a number
from 1 to 5, preferably 1-3, and z is a number from 1 to 30, prefer-
ably 5-15.
As component (d), the mixtures of the invention preferably contain an
amine-terminated rubber based on butadiene or butadiene-acrylonitrile,
especially an amine-terminated rubber based on butadiene.
The mixtures of the invention can be prepared by thoroughly mixing all
the components or dissolving them in one another, it being possible for
the individual components to be added in different orders. For example,
the thermoplastic can be dissolved in the epoxy resin, with heating, and
the other ingredients can be added after the solution has cooled. Another
possible method is to prepare a solution of the thermoplastic in an inert
solvent, e.g. in methylene chloride, and to mix this solution with the
mixture of epoxy resin hardeners.
The mixtures of the invention have many possible uses and are suitable
for example as casting resins, laminating or impregnating resins,
moulding compounds, sealing compounds and potting and insulating com-
pounds in electrical engineering, and preferably as adhesives and as
matrix resins for composites, especially for the manufacture of prepregs
for fibre-reinforced plastics.
If desired, especially when modifiers are also used, the mixtures of the
invention can be dissolved in an organic solvent such as toluene, xylene,
methyl ethyl ketone, methylene chloride or a similar solvent or solvent
mixture conventionally used in the paint industry. Such solutions are
particularly suitable as impregnating or coating compositions.
Conventional modifiers, such as extenders, fillers and reinforcing
agents, pigments, dyes, organic solvents, plasticizers, levelling agents,
thixotropic agents, flame retardants or mould release agents, can also be
added to the curable mixtures of the invention, before curing, in any
~_ 11 - 1 337~88
phase. Examples of extenders, reinforcing agents, fillers and pigments
which can be used in the curable mixtures of the invention are: liquid
coumarone-indene resins, textile fibres, glass fibres, asbestos fibres,
boron fibres, carbon fibres, polyethylene powder, polypropylene powder,
quartz powder, mineral silicates such as mica, asbestos powder, ground
shale and kaolin, powdered chalk, antimony trioxide, bentones, litho-
pones, barite, titanium dioxide, carbon black, graphite, oxide pigments
such as iron oxide, or metal powders such as aluminium powder or iron
powder. If the mixtures of the invention are used for the manufacture of
prepregs, it is particularly desirable to add short fibres.
Examples of levelling agents which can be added when the curable mixtures
are used especially for surface protection are silicones, liquid acrylic
resins, cellulose acetobutyrate, polyvinylbutyral, waxes, stearates etc.
(some of which are also used as mould release agents).
Examples of plasticizers which can be used to modify the curable mixtures
are dibutyl, dioctyl and dinonyl phthalate, tricresyl phosphate, tri-
xylenyl phosphate and diphenoxyethylformal.
The mixtures of the invention are preferably cured by being heated to atemperature in the range from 120 to 250C, especially 160 to 220C.
Curing can also be carried out in two or more stages, in known manner,
the first curing stage being carried out at a low temperature and the
postcure at a higher temperature.
If desired, active diluents, e.g. the diglycidyl ether of neopentyl
glycol, butanediol or hexanediol, can be added to the curable mixtures in
order to lower the viscosity.
The present invention further relates to the use of the mixtures of theinvention for the manufacture of cured moulded materials and to their use
for the manufacture of prepregs for fibre-reinforced composites. The
prepregs can be manufactured in a manner known per se, e.g. by the
impregnation process in the presence of one of the above-mentioned
solvents or a halogenated solvent such as methylene chloride, or by the
hot melt process.
_ - 12 ~ 1 337088
The moulded materials of the invention are distinguished in general by
high glass transition temperatures in combination with good mechanical
strength properties, and especially by an excellent fracture toughness
and a very high extensibility.
In the Examples, the following compounds are used as epoxy resin,
thermoplastic or rubber:
Epoxy resin A: N,N,N',N'-Tetraglycidyl derivative of 4,4'-diaminodi-
phenylmethane with an epoxy content of 7.8 equivalents/kg and a viscosity
of 13,500 mPa-s at 50C.
Epoxy resin B: N,N,N',N'-Tetraglycidyl derivative of 4,4'-diaminodi-
phenylmethane with an epoxy content of 9.1 equivalents/kg and a viscosity
of 5000 mPa-s at 50C.
Epoxy resin C: Bisphenol A diglycidyl ether with an epoxy content of
5.2 to 5.4 equivalents/kg and a viscosity of 103-123 MPa-s at 25C.
Epoxy resin D: Bisphenol F diglycidyl ether with an epoxy content of
5.5 to 5.9 equivalents/kg and a viscosity of 3000-10,000 MPa-s at 25C.
Epoxy resin E: Phenolic novolak epoxy resin with an epoxy content of
5.6 to 5.8 equivalents/kg and a melting viscosity of 1100-1700 MPa-s at
50C.
Epoxy resin F: N,N-Diglycidyl-p-aminophenol glycidyl ether (ERLA~ 0510).
Polysulfone I: Polysulfone Udel P1800~ (Union Carbide Corporation) with a
melting point in the range from 350 to 370C, a deflection temperature
under load (according to ASTM D 648) of 175C, a glass transition
temperature of 200C and a molecular weight range of ca. 22,000-23,000.
Polyetherimide I: Polyetherimide Ultem~ 1000 (General Electric) with a
glass transition temperature of 219C and containing the repeat struc-
tural unit of the formula
`~ 1 337088
- 13 - 21489-7779
~ C
~ CH3 / ~ / \ ~-\
Polyethersulfone I: Polyethersulfone Victrex~) P 5003 (ICI) with a deflec-
tion temperature under load (according to IS0 75) of 215C and containing
the repeat structural unit of the formula
~---SO2~
Example 1: 15 g of polysulfone I are dissolved at 150C in 128 g (1 epoxy
equivalent) of epoxy resin A. 71 g (0.9 amine hydrogen equivalent) of
bis(3,5-diethyl-4-aminophenyl)methane are then mixed with the solution
and the mixture is cooled to about 130C. 10 g (0.07 amine hydrogen
equivalent) of N,N'-dicyclohexyl-1,6-diaminohexane are mixed with this
mixture. The resin mixture is viscous at room temperature and still tacky
after storage for 5 weeks at room temperature. The mixture is freed from
included air bubbles and poured into a 4 mm thick aluminium (Anticorodal)
mould. Mouldings having the following properties are obtained after a
curing time of 2 hours at 160C and 2 hours at 180C:
Glass transition temperature (Tg, measured with a Mettler "TMA 3000"
instrument as the peak maximum of the penetration speed) = 198C
Flexural strength (FS) according to IS0 178 at 23C = 131 MPa
Flexural elongation (FE) according to IS0 178 = 11 %.
Example 2: A resin mixture is prepared as in Example 1, this time withthe addition of 77 g (1.0 equivalent) of bis(3,5-diethyl-4-aminophenyl)-
methane and no other diamine. The mixture loses its tackiness after
storage for 6 days at room temperature. The mouldings cured under
identical conditions have the following properties:
- 14 - ~ 8
Tg = 203C
FS = 133 MPa
FE = 13.2 %.
Example 3: 40 g of polyetherimide I are dissolved in 200 g of methylenechloride at room temperature and mixed thoroughly with 128 g (1 equiva-
lent) of epoxy resin A. The solvent is evaporated off with stirring and
heating to 150C. 71 g (0.9 equivalent) of bis(3,5-diethyl-4-amino-
phenyl)methane and 10 g (0.07 equivalent) of N,N'-dicyclohexyl-1,6-di-
aminohexane are added as in Example 1. The curable mixture has a very
high viscosity at room temperature and still exhibits a good tackiness
even after storage for 20 days. In the DSC diagram with a heating rate of
10/min, the curing reaction reaches the ~x; ~ exothermicity (T max) at
235C. The viscosity (~) is 7600 mPa-s at 120C. Mouldings having the
following properties are obtained after a curing time of 2 hours at 160C
and 2 hours at 200C:
Tg = 208C
FS = 142 MPa
FE = 10.1 %.
Example 4: Example 3 is repeated, this time with a mixture of 20 g of
polysulfone I and 20 g of polyetherimide I being used instead of 40 g of
polyetherimide I. The mouldings produced under identical curing condi-
tions have the following properties:
T max (DSC) = 237C
= 4800 mPa-s
Tg = 139 MPa
FE = 9.0 %.
Example 5: Example 3 is repeated and 3 g of the amine-terminated butyl-nitrile rubber Hycar~ ATBN 1300 x 16 (Goodrich) are also added to the
curable mixture. The mouldings produced under identical curing conditions
have the following properties:
T max (DSC) = 234C
(120C) = 7000 mPa-s
~~ - 15 - 1 3 3 7 0 8 8
FS = 141 MPa
FE = 12.9 %.
Example 6: 35 g of polyetherimide I are dissolved in 200 ml of methylene
chloride. 110 g (1 equivalent) of epoxy resin B are then added and the
methylene chloride is distilled off by heating, with stirring. The
mixture is then heated to about 150C and 55 g (0.7 equivalent) of
bis(3,5-diethyl-4-aminophenyl)methane, 24 g (0.3 equivalent) of bis(3-
methyl-4-amino-5-isopropylphenyl)methane and 3 g of Hycar~ ATBN 1300 x 16
are dissolved therein. Mouldings produced from this mixture as in
Example 1 have the following properties:
Tg = 197C
FS = 148 MPa
FE = 11.6 %.
The uncured resin mixture has a viscosity of 2550 mPa-s at 120C and a
viscosity of 52,000 mPa-s at 70C and can easily be processed, for
example from a solution in methylene chloride, to give thin films
(0.1 mm), as used for the manufacture of prepregs. The films exhibit a
good tackiness and are still tacky and transparent even after storage for
several days, i.e. the hardener has not crystallized out in the resin.
Example 7: A curable mixture consisting of 60 g (0.47 equivalent) of
epoxy resin A, 40 g (0.21 equivalent) of epoxy resin C, 31.8 g
(0.41 equivalent) of bis(3,5-diethyl-4-aminophenyl)methane, 15.2 g
(0.24 equivalent) of bis(3-ethyl-5-methyl-4-aminophenyl)methane and 20 g
of polysulfone I is prepared as in Example 1. The mixture can be pro-
cessed by melting to give a film of good tackiness. After storage for
several days, the film shows no signs of recrystallization. The mouldings
cured under such conditions have the following properties:
Tg = 206C
FS = 130 MPa
FE = 11.3 %.
~ - 16 - 1 33708~
Example 8: Another mixture is prepared from 80 g of epoxy resin A, 20 g
of epoxy resin D, 5 g of a carboxyl-terminated rubber based on butadiene
and acrylonitrile (= Hycar~ CTBN 1300 x 13), 43 g of bis(3,5-diethyl-4-
aminophenyl)methane (hardener II), 11.5 g of bis(3-methyl-4-amino-5-iso-
propylphenyl)methane (hardener I), 10 g of polysulfone I and 15 g of
polyetherimide I. Before the thermoplastic and amine are added, the
carboxyl-terminated rubber is prereacted for 1 hour at 150C. The film
obtained shows no signs of recrystallization. The cured moulding has the
following properties:
Tg = 205C
FS = 117 MPa
FE = 5.1 %.
Example 9: Tacky films which also do not crystallize out are obtained
with the following mixtures:
A B
Epoxy resin A 80 g (0.63 equiv.) 80 g (0.63 equiv.)
Epoxy resin E 20 g (0.11 equiv.) 0
Epoxy resin F 0 20 g (0.21 equiv.)
Hardener II 43 g (0.56 equiv.) 43 g (0.56 equiv.)
Hardener I 11.5 g (0.15 equiv.) 0
Hardener III*) 0 14 g (0.15 equiv.)
Polyethersulfone I 20 g 20 g
*) Hardener III = bis(3,5-diethyl-4-amino-6-chlorophenyl)methane
The mouldings cured as in Example 1 have the following properties:
A B
Tg [C] 208 213
FS [MPa] 138 145
FE [%] 8.4 10.2.
Example 10: Production of carbon fibre laminates:
a) With the mixture according to Example 3, a unidirectional prepreg is
produced by melting ("T-300 6K" carbon fibre from TORAY). A unidirec-
tional laminate is produced in an autoclave by the vacuum bag technique
(heating by 3C/min up to 180C, followed by 3 hours at 180C and 7 bar
_ - 17 - 1 3 3 7 0 8 8
pressure). The laminates exhibit an interlaminar shear strength (ILSS
according to DIN 29 971) of 94 MPa at 23C and of 56 MPa at 120C. After
storage in water for 14 days at 70C, the ILSS is 83 MPa at 23C and
44 MPa at 120C.
b) A laminate produced from a mixture according to Example 6 has the
following properties:
Tg = 219C
ILSS at 23C = 81 MPa
ILSS at 120C = 60 MPa
ILSS at 23C = 88 MPa } after storage in water
ILSS at 120C = 51 MPa for 14 days at 70C
FS at 0C = 1870 MPa
FS at 90C = 91 MPa
Water absorption = 0.5 %.
