Composition of butadiene/polar comonomer copolymer, aromatic reactive end group-containing prepolymer and epoxy resin

The invention relates to compositions containing A) a liquid copolymer based on butadiene and at least one polar, ethylenically unsaturated comonomer, and B) a polyether prepolymer capped with hydroxyarylcarboxylic or hydroxyaralkylcarboxylic acids, or a capped polyester, polythioester or polyamide containing polyether segments. The phenolic hydroxyl group in component B) can also be etherified with epichlorohydrin and this product can be converted to an episulfide, if desired, or the phenolic hydroxyl group can be reacted with cyanogen halide to form a cyanate group. The stock compositions can be used in combination with epoxy resins to manufacture structural adhesives or sealing compounds.

The present invention relates to novel flexibilizer combinations for epoxy 
resins, to compositions containing these combinations and epoxy resins, to 
novel components of the said combinations, to the cured products of the 
modified epoxy resins and to the use of the said combinations for 
flexibilizing epoxy resins. 
It is known from U.S. Pat. No. 3,944,594 that esters of sterically hindered 
phenols with oligomeric glycols or thioglycols can be used for stabilizing 
organic polymers, inter alia polydienes, against oxidative degradation. As 
stabilizers, these compounds are normally used only in small amounts. 
It is also known that epoxy resins can be modified by the addition of 
copolymers based on butadiene and acrylonitrile or by the addition of 
adducts of such copolymers and epoxy resins. 
It is known from DE-A-3,331,903 that polyphenols with an elasticizing 
action, such as the esterification product of a higher-molecular diol with 
a hydroxyphenylcarboxylic acid, can be used for the preparation of 
water-dispersible binders for cationic electrophoretic enamels. 
The effect of such additives is generally to increase the impact strength 
and flexibility of the cured product. The peel strength, however, 
generally leaves something to be desired. The incorporation of such 
polymers normally reduces the lap shear strength and lowers the glass 
transition temperature. 
Combinations of impact strength modifiers have now been found which, when 
mixed with epoxy resins, effect a significant increase in the peel 
strength, have a reduced tendency towards crack propagation and permit 
high peel strengths without loss of lap shear strength. 
Furthermore, depending on the resin formulation, these modifiers make it 
possible to produce elastic products of high peel strength and low glass 
transition temperature or high-strength products of high glass transition 
temperature and high peel strength; the high-strength products are 
distinguished by high fracture toughness and the crack propagation, even 
under very high shock-like impact stress, is markedly reduced. 
The impact strength modifiers of the invention can be used with epoxy 
resins to prepare low-viscosity formulations, which is advantageous at the 
processing stage. 
The cured epoxy resins are also distinguished by a good temperature 
resistance. 
The present invention relates to compositions comprising 
A) a liquid copolymer based on butadiene and at least one polar, 
ethylenically unsaturated comonomer, and 
B) a compound of formula I: 
##STR1## 
wherein m is 1 or 2, n is 2 to 6, X is --O--, --S-- or --NR.sup.3 --, Y is 
a radical selected from the group comprising --OH, --NHR.sup.3, --OCN, 
##STR2## 
R.sup.1 is a radical of a polyether prepolymer with hydroxyl, mercapto or 
amino end groups or of a segmented polyester, polythioester or polyamide 
prepolymer with hydroxyl, mercapto or amino end groups, containing at 
least 30 mol%, based on the said segmented prepolymer, of polyether 
segments after removal of the terminal functional groups, R.sup.2 is a 
carbocyclic aromatic or araliphatic radical of valency m+1 with groups Y 
bonded direct to the aromatic ring, R.sup.3 is hydrogen, C.sub.1 -C.sub.6 
-alkyl or phenyl and R.sup.4 is methyl or, in particular, hydrogen. 
Component A) is a selected liquid elastomeric copolymer based on butadiene 
and preferably contains end groups which react with epoxy resins. 
The molecular weight of these copolymers is preferably 500-5000, in 
particular 1000-3000. 
This component can be used as such or as an adduct with an epoxy resin, 
preferably with a diglycidyl ether based on a bisphenol. 
The term "liquid copolymer" will be understood in the context of the 
present description as meaning a compound which is free-flowing at 
temperatures below 80.degree. C. and can easily be mixed with an epoxy 
resin. 
Examples of polar, ethylenically unsaturated comonomers for the preparation 
of component A) are (meth)acrylic acid, (meth)acrylic acid esters, for 
example the methyl or ethyl esters, (meth)acrylamide, fumaric acid, 
itaconic acid, maleic acid or esters or half-esters thereof, for example 
the monomethyl or dimethyl esters, maleic or itaconic anhydride, vinyl 
esters, for example vinyl acetate, polar styrenes, for example 
ring-chlorinated or ring-brominated styrenes, or, in particular, 
acrylonitrile or methacrylonitrile. 
In addition to polar, ethylenically unsaturated comonomers, component A) 
can also contain non-polar, ethylenically unsaturated comonomers, examples 
being ethylene, propylene or, in particular, styrene or substituted 
styrenes such as vinyltoluene. 
Component A) can be a random copolymer, block copolymer or graft copolymer. 
The proportion of comonomers in component A) can vary within wide limits. 
This component is chosen so that an elastomeric phase is formed in 
combination with component B) and, if appropriate, an epoxy resin C). An 
elastomeric phase of this type is normally characterized by a glass 
transition temperature below 0.degree. C. The system in question can be 
homogeneous or heterogeneous. 
An elastomeric phase may already be present in component A); alternatively 
the elastomeric phase may only be formed by selecting suitable components 
A), B) and, if appropriate, C). 
If it is desired to have heterogeneous systems, the components are normally 
chosen so that the difference between the solubility parameters of A) 
and/or B) and those of C) is between 0.2 and 1.0, preferably between 0.2 
and 0.6. These selection criteria are described for example by C. B. 
Bucknall in "Toughened Plastics", chapter 2, Applied Science Publishers 
Ltd., London 1977. 
Especially preferred components A) are liquid butadiene/acrylonitrile 
copolymers. 
Other most preferred components A) are liquid butadiene/acrylonitrile 
copolymers containing functional groups which react with epoxy resins, for 
example carboxyl, hydroxyl or amino groups. 
Examples of such copolymers are acrylonitrile/butadiene rubbers containing 
carboxyl, hydroxyl or amino groups, for example compounds of the 
Hycar.RTM. type from Goodrich. 
Preferred types of such rubbers contain the structural units of the 
following formulae IIa to IId and the end groups G: 
##STR3## 
wherein R.sup.a is hydrogen or methyl, R.sup.b is --COOH, --COOR.sup.c 
--COOR.sup.c or --CONH.sub.2, R.sup.c is an aliphatic radical, preferably 
methyl, and G is selected from the group comprising --R--COOH, --R--OH, 
##STR4## 
wherein R is an alkylene radical; the proportion of radicals IIa, IIb and 
IIc is preferably 5-50% by weight and the proportion of radical IId is 
preferably 0-30% by weight or, in the case of radicals having free 
carboxyl groups, preferably 0-10% by weight, the amounts being based on 
the total amount of radicals IIa, IIb, IIc and, if appropriate, IId. 
Component A) is preferably used as the adduct of a butadiene/acrylonitrile 
copolymer containing functional groups which react with epoxy resins, and 
an epoxy resin. Such adducts are prepared in a manner known per se by 
heating the reactive butadiene/acrylonitrile rubber and the epoxy resin, 
if necessary with a catalyst, to form a fusible but still curable 
precondensation product. Examples of catalysts used are 
triphenylphosphine, tertiary amines, quaternary ammonium or phosphonium 
salts or chromium acetylacetonate. 
Component B) is derived from polyether or polyester, polythioester or 
polyamide prepolymers with hydroxyl, mercapto or amino end groups and 
containing a minimum proportion, as defined above, of polyether segments, 
the end groups of which are modified as described below. Such prepolymers 
are known per se. 
The molecular weight of such prepolymers is normally in the range from 500 
to 20,000 (number-average), preferably in the range from 500 to 3000. 
The average functionality of these prepolymers is at least 2, preferably 2 
to 3. 
It is especially preferred to use polyether or segmented polyester, 
polythioester or polyamide prepolymers which yield water-insoluble 
compounds of formula I. These are understood in the context of the present 
description as meaning compounds which are soluble in water to the extent 
of less than 5% by weight, preferably less than 1% by weight, and which, 
when stored in water, only take up a small amount of water, preferably 
less than 5% by weight, or exhibit only slight swelling. 
The polyether or segmented polyester, polythioester or polyamide 
prepolymers can in some cases contain grafter 1-olefins, it being possible 
for the said 1-olefins to contain polar groups, such as nitrile, ester or 
amide groups, in addition to non-polar groups. 
R.sup.1 is preferably a polyalkylene glycol radical, in particular a 
polypropylene glycol or polybutylene glycol radical, with hydroxy, 
mercapto or amino end groups, after removal of the functional groups. 
Polyalkylene glycols with hydroxyl end groups can be obtained for example 
by the anionic polymerization, copolymerization or block copolymerization 
of alkylene oxides, such as ethylene oxide, propylene oxide or butylene 
oxide, with difunctional or polyfunctional alcohols, such as 
butane-1,4-diol, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, 
hexane-1,2,6-triol, glycerol, pentaerythritol or sorbitol, or with amines, 
such as methylamine, ethylenediamine or 1,6-hexylenediamine, as starter 
components, or by the cationic polymerization or copolymerization of 
cyclic ethers, such as tetrahydrofuran, propylene oxide or ethylene oxide, 
with acid catalysts, such as BF.sub.3 etherate, or by the polycondensation 
of glycols which can undergo polycondensation with the elimination of 
water, such as hexane-1,6-diol, in the presence of acid etherification 
catalysts, such as p-toluenesulfonic acid. 
It is also possible to use alkoxylation products of phosphoric acid or 
phosphorous acid with ethylene oxide, propylene oxide, butylene oxide or 
styrene oxide. 
Polyalkylene glycols with amino end groups are derived for example from the 
polyalkylene glycols with hydroxyl end groups described above, such 
compounds containing primary hydroxyl groups, for example polybutylene 
glycol, being reacted with acrylonitrile and the products then being 
hydrogenated, or such compounds containing secondary hydroxyl groups being 
reacted with ammonia. Suitable polypropylene glycols with amino end groups 
are the compounds commercially available from Texaco under the name 
"Jeffamines.RTM.". 
Polyalkylene glycols with mercapto end groups can be prepared in a manner 
known per se from the corresponding polyalkylene glycols with hydroxyl or 
amino end groups, for example by the addition of mercaptocarboxylic acids 
or esters thereof, such as mercaptoacetic acid (esters), onto polyalkylene 
glycols with hydroxyl or amino end groups, or by the addition of 
episulfides onto polyalkylene glycols with hydroxyl or amino end groups. 
The preferred radicals R.sup.1 derived from the polyalkylene glycol 
derivatives listed above include the structural units of formulae IIIa, 
IIIb, IIIc, IIId and IIIe: 
##STR5## 
wherein y is 5 to 90, in particular 10 to 90, Z is 10 to 40, R.sup.5 is a 
radical of an aliphatic diol after removal of the two OH groups, and 
R.sup.6 is a radical of an aliphatic triol after removal of the three OH 
groups. 
Other preferred polyalkylene glycol prepolymers with hydroxyl, mercapto or 
amino end groups contain grafter 1-olefins, in particular styrene or 
acrylic acid derivatives such as acrylic acid esters or acrylonitrile. 
The polyesters, polythioesters or polyamides with hydroxyl, mercapto or 
amino end groups and segmented with polyether radicals are normally 
derived from polyesters based on aliphatic, cycloaliphatic or aromatic 
polycarboxylic acids, in particular dicarboxylic acids, and on aliphatic 
or cycloaliphatic polyols or thioalcohols, in particular diols or triols, 
or on alilphatic or cycloaliphatic polyamines, in particular diamines or 
triamines; alternatively they are derived from lactones or lactams into 
which at least 30 mol% , based on the prepolymer component, of polyether 
segments has been introduced by condensation. 
Examples of aliphatic polycarboxylic acids are oxalic acid, succinic acid, 
glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 
sebacic acid or dimerized or trimerized linoleic acid, examples of 
cycloaliphatic polycarboxylic acids are tetrahydrophthalic acid, 
4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 
4-methylhexahydrophthalic acid; examples of aromatic polycarboxylic acids 
are phthalic acid, isophthalic acid or terephthalic acid. 
Examples of polyols are ethylene-1,2-diol, propane-1,2-diol, 
propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 
octane-1,8-diol, decane-1,10-diol or dodecane-1,12-diol, di-, tri- and 
tetra-ethylene glycol, di-, tri- and tetra-propylene glycol, di-, tri- and 
tetra-butylene glycol, 2,2-dimethylpropane-1,3-diol, 
1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, 
hexane-1,2,6-triol, pentaerythritol, sorbitol, 1,3- or 
1,4-dihydroxycyclohexane, cyclohexane-1,4-dimethanol, 
bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-hydroxy-cyclohexyl)propane or 
1,1-bis(hydroxymethyl)cyclohex-3-ene. 
Examples of thioalcohols are 1,2-dimercaptoethane or 1,3-dimercaptopropane. 
Examples of polyamines are 1,2-diaminoethane, 1,3-diaminopropane, 
1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, di-, tri- and 
tetra-1,2-diaminoethane, di-, tri- and tetra-1,3-diaminopropane, di-, tri- 
and tetra-1,4-diaminobutane, piperazine, 2,5-dimethylpiperazine, 
1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1,4-diaminocyclohexane, 
1,4-bis(aminomethylene)cyclohexane and bis(4-aminocyclohexyl)-methane. 
An example of a lactone is .epsilon.-caprolactone; an example of a lactam 
is .epsilon.-caprolactam. 
The polyether segments which have to be present in the polyester, 
polythioester or polyamide prepolymers can be present either as the only 
alcohol or amine component in the prepolymers or in combinations with 
other alcohol or amine components in the prepolymer. Thus the prepolymers 
can be prepared by the condensation of polycarboxylic acids, polylactones 
or polylactams with polyether blocks containing hydroxyl, mercapto or 
amino end groups, or by the condensation of polycarboxylic acids and 
polyols or polyamines in combination with polyether blocks containing 
hydroxyl, mercapto or amino end groups. 
Preferred polyether blocks are the polyalkylene glycols with hydroxyl, 
mercapto or amino end groups listed above. 
The subscript n is preferably 2 or 3 and the subscript m is preferably 1. 
X is preferably --O--, --S-- or --NH--. 
Y is preferably --OH, --HN.sub.2, --OCN, 
##STR6## 
in particular --OH, --OCN, 
##STR7## 
R.sup.2 as a carbocyclic aromatic or araliphatic radical or valency m+1 
with groups Y bonded direct to the aromatic ring is normally a mononuclear 
or polynuclear aromatic radical which can be unsubstituted or substituted 
by inert radicals. Polynuclear radicals can be fused or the rings can be 
linked to one another via direct C--C bonds or via bridging groups. 
R.sup.2 is preferably a divalent mononuclear or dinuclear aromatic radical 
or a divalent mononuclear araliphatic radical, in particular a radical of 
a hydroxybenzoic acid. 
Examples of inert substituents are alkyl, alkenyl, alkynyl, alkoxy or 
halogen. 
R.sup.2 is preferably a radical of formula IVa, IVb or IVc: 
##STR8## 
wherein R.sup.7 is C.sub.1 -C.sub.6 -alkyl, C.sub.2 -C.sub.6 -alkenyl, 
C.sub.2 -C.sub.6 -alkynyl, C.sub.1 -C.sub.6 -alkoxy, halogen, in 
particular chlorine or bromine, or phenyl, p is an integer from 0 to 3, in 
particular 0 or 1, q is 1,2 or 3, in particular 1 or 2, and Q is a direct 
bond, --C.sub.q H.sub.2q --, in particular --CH.sub.2 -- or 
--C(CH.sub.3).sub.2 --, or --O--, --S--, --SO.sub.2 --, --CO-- or 
--C(CF.sub.3).sub.2 --. 
In preferred compounds of formula I, m is 1, n is 2 or 3, R.sup.1 is a 
radical of a polyalkylene glycol with hydroxyl, mercapto or amino end 
groups after removal of the functional groups, and R.sup.2 is a radical of 
formula IVd, IVe, IVf or IVg: 
##STR9## 
R.sup.3 is preferably methyl or, in particular, hydrogen. 
Any radicals as C.sub.1 -C.sub.6 -alkyl can be linear or branched radicals, 
linear radicals being preferred. 
Specific examples of alkyl radicals are methyl, ethyl, n-propyl, isopropyl, 
n-butyl, isobutyl, n-pentyl or n-hexyl, methyl being preferred. 
Any radicals as C.sub.1 -C.sub.6 -alkoxy can be linear or branched 
radicals, linear radicals being preferred. 
Specific examples of alkoxy radicals are methoxy, ethoxy, n-propoxy, 
isopropoxy, n-butoxy, isobutoxy, n-pentoxy or n-hexyloxy, methoxy being 
preferred. 
Any radicals as C.sub.2 -C.sub.6 -alkenyl are preferably linear radicals, 
for example vinyl, allyl, prop-1-enyl, but-1-enyl, pent-1-enyl or 
hex-1-enyl, vinyl and allyl being preferred. 
Any radicals as C.sub.2 -C.sub.6 -alkynyl are preferably linear radicals, 
for example ethynyl, propargyl, but-1-ynyl, pent-1-ynyl or hex-1-ynyl, 
propargyl being preferred. 
Any radicals as halogen are preferably chlorine or bromine. 
The compounds of formula I can be obtained in a manner known per se by 
capping the hydroxyl, mercapto or amino end groups of the polyether 
prepolymers or of the segmented polyesters or polyamides with 
hydroxycarboxylic acids HOOC--R.sup.2 --(OH).sub.m or aminocarboxylic 
acids HOOC--R.sup.2 --(NHR.sup.3).sub.m, or ester derivatives thereof, in 
a molar amount essentially corresponding to the proportion of these end 
groups. 
Examples of preferred hydroxybenzoic or aminocarboxylic acids (derivatives) 
are p-hydroxylbenzoic acid, p-aminobenzoic acid, salicylic acid and 
anthranilic acid, as sell as the methyl or ethyl esters thereof. 
The polyester or polyamide resins of formula I can be prepared by general 
procedures applied to the preparation of such resins. Thus the 
esterification can advantageously be carried out by melt condensation of 
the carboxylic acid component(s) and the polyol or polyamine, the 
reactants being heated for example to a temperature of 240.degree. C., 
with stirring. It is possible here to pass an inert gas, for example 
nitrogen, through the reaction mixture in order to remove the water formed 
during the reaction, or the alcohol in cases where an ester has been used 
as the functionalized carboxylic acid derivative. A further possibility is 
to apply a slight vacuum at the end of the esterification reaction, if 
necessary, in order to remove residual low-molecular cleavage products. 
The preferred temperature range for the melt condensation is 
160.degree.-200.degree. C. The polycondensation can be carried out in the 
presence of a catalyst, if necessary, examples of catalysts being Sn(IV) 
compounds such as dibutyl-tin oxide or dibutyl-tin dilaurate. 
However, it is also possible to use other forms of polycondensation, for 
example polycondensation in solution, in suspension or in bulk. 
The anthranilamides can be prepared by reacting polyethers containing amino 
end groups or segmented polyamides containing amino end groups with 
isatoic anhydride. 
The compounds of formula I in which Y is --OCN can be prepared starting 
from the compounds of formula I in which Y is --OH. This is done by 
reacting the polyesters or polyamides containing phenol end groups, of 
formula I, with cyanogen halide, in particular with cyanogen bromide, in 
the presence of a base, for example a tertiary amine such as 
triethylamine, in an inert aprotic solvent. 
Examples of inert aprotic solvents are aromatic hydrocarbons such as 
toluene or xylene, or ketones such as methyl isobutyl ketone. 
The reaction is normally carried out by mixing essentially equivalent 
amounts of compounds of formula I in which Y is --OH and cyanogen halide, 
with cooling, for example at 0.degree. C., and by adding the tertiary 
amine at this temperature. 
The compounds of formula I in which Y is 
##STR10## 
can be prepared starting from the compounds of formula I in which Y is 
--OH. This is done by reacting the polyesters or polyamides containing 
phenol end groups, of formula I, with epichlorohydrin or 
.beta.-methylepichlorophydrin in the presence of a base, for example an 
alkali metal carbonate or alkali metal hydroxide, in an inert solvent. 
Examples of such solvents are listed above. The addition of 
epichlorohydrin or .beta.-methylepichlorohydrin and the subsequent 
dehydrohalogenation can be carried out in one or two stages. 
The reaction is normally carried out at elevated temperature, for example 
in the range from 60.degree. to 120.degree. C. 
The analogous episulfides can be prepared in a manner known per se by 
reacting the epoxides of formula I described above with potassium 
thiocyanate or with thiourea. 
The compounds of formula I normally have a molecular weight 
(number-average) of 600 to 20,000, in particular 800 to 5000. 
The compounds of formula I in which Y is --OCN or 
##STR11## 
are novel and also represent a subject of the invention. 
The compositions of the invention consisting of A) and B) can be processed 
with epoxy resins to give cured products having the advantageous 
properties described above. 
The invention therefore further relates to compositions containing 
components A) and B), as defined above, and C) an epoxy resin with at 
least two 1,2-epoxy groups per molecule, or containing an adduct of 
component A) and an epoxy resin, component B) and, if appropriate, 
component C), or containing component A), an adduct of component B) and an 
epoxy resin, and, if appropriate, component C), or containing an adduct of 
component A) and an epoxy resin, an adduct of component B) and an epoxy 
resin, and, if appropriate, component C). 
Combinations of component A) and an adduct of an epoxy resin C) and a 
compound of formula I in which Y is --OH are especially preferred. Adducts 
of component C) and component B) can be prepared analogously to the 
formation of adducts of reactive components A) and epoxy resins, described 
above. 
The compositions of the invention can be prepared in conventional manner by 
mixing the components with the aid of known mixing units (stirrers, 
rolls). 
In principle, any compound conventionally used in epoxy resin technology, 
including mixtures of several epoxy resins, can be used as component C). 
Examples of epoxy resins are: 
I) Polyglycidyl and poly(.beta.-methylglycidyl) esters which can be 
obtained for example by reacting a compound containing at least two 
carboxyl groups in the molecule with epiclorohydrin, glycerol 
dichlorohydrin or .beta.-methylepichlorohydrin in the presence of bases. 
Examples of compounds with at least two carboxyl groups in the molecule are 
aliphatic polycarboxylic acids, cycloaliphatic polycarboxylic acids or 
aromatic polycarboxylic acids, as already mentioned above as components 
for the formation of polyesters or polyamides. Examples of tricarboxylic 
and higher carboxylic acids are, in particular, aromatic tricarboxylic or 
tetracarboxylic acids, such as trimellitic acid, trimesic acid, 
pyromellitic acid or benzophenonetetracarboxylic acid, and dimerized or 
trimerized fatty acids, for example those commercially available under the 
name Pripol.RTM., or copolymers of (meth)acrylic acid with copolymerizable 
vinyl monomers, for example the 1:1 copolymers of methacrylic acid with 
sytrene or with methyl methacrylate. 
II) Polyglycidyl and poly(.beta.-methylglycidyl) ethers which can be 
obtained for example by reacting a compound containing at least two 
alcoholic hydroxyl groups and/or phenolic hydroxyl groups in the molecule 
with epichlorohydrin, glycerol dichlorohydrin or 
.beta.-methylepichlorohydrin under alkaline conditions or in the presence 
of an acid catalyst, and the treating the product with alkali. 
Examples of compounds with at least two alcoholic hydroxyl groups and/or 
phenolic hydroxyl groups in the molecule are aliphatic or cycloaliphatic 
alcohols, such as those already mentioned above as components for the 
formation of polyesters, or alcohols containing aromatic groups, such as 
N,N-bis(2-hydroxyethyl)aniline or 
p,p'-bis(2-hydroxyethylamino)diphenylmethane, or mononuclear or 
polynuclear phenols, such as resorcinol, hydroquinone, 
bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, brominated 
2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl) ether, 
bis(4-hydroxyphenyl sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane or 
novolaks which can be obtained by condensing aldehydes, such as 
formaldehyde, acetaldehyde, chloral or furfuraldehyde, with unsubstituted, 
alkyl-substituted or halogen-substituted phenols, such as phenol, the 
bisphenols described above, 2- or 4-methylphenol, 4-tert-butylphenol, 
p-nonylphenol or 4-chlorophenol. 
III) Poly(N-glycidyl) compounds which can be prepared for example by 
dehydrochlorinating reaction products of epichlorohydrin with amines which 
contain at least two amino hydrogen atoms. 
Examples of amines on which such epoxy resins are based are aliphatic or 
cycloaliphatic amines, such as those mentioned above as components for the 
formation of polyamides, aromatic amines, such as aniline, p-toluidine, 
bis(4-aminophenyl)methane, bis(4-aminophenyl)sulfone or bis(4-aminophenyl) 
ether, or araliphatic amines, such as m-xylylenediamine. 
However, the poly(N-glycidyl) compounds also include triglycidyl 
isocyanurate, N,N'-diglycidyl derivatives of cycloalkyleneureas such as 
ethyleneurea or 1,3-propyleneurea, and N,N'-diglycidyl derivatives of 
hydantoins such as 5,5-dimethylhydantoin. 
IV) Poly(S-glycidyl) compounds, for example di-S-glycidyl derivatives which 
are derived from dithiols, such as ethane-1,2-dithiol, or from 
bis(4-mercaptomethylphenyl) ether. 
V) Cycloaliphatic epoxy resins or epoxidation products of dienes or 
polyenes, such as cycloaliphatic epoxy resins which can be prepared for 
example by epoxidizing ethylenically unsaturated cycloaliphatic compounds. 
Examples are 1,2-bis(2,3-epoxycyclopentoxy-ethane, 2,3-epoxycyclopentyl 
glycidyl ether, diglycidyl cyclohexane-1,2-dicarboxylate, 
3,4-epoxycyclohexyl glycidyl ether, bis(2,3-epoxycyclopentyl) ether, 
bis(3,4-epoxycyclohexyl) ether, 
5(6)-glycidyl-2-(1,2-epoxyethyl)bicyclo[2.2.1]heptane, dicyclopentadiene 
dioxide, cyclohexa-1,3-diene dioxide, 
3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexanecarboxy 
late or 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate. 
It is also possible, however, to use epoxy resins in which the 1,2-epoxy 
groups are bonded to different heteroatoms or functional groups; such 
compounds include, for example, the N,N,O-triglycidyl derivative of 
4-aminophenol, the glycidyl ether glycidyl ester of salicyclic acid, 
N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin or 
2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3-yl)propane. 
Diglycidyl ethers based on bisphenol, in particular bisphenol A, are 
preferred. 
The compositions of the invention normally contain additional hardeners D) 
known per se to those skilled in the art, if necessary in combination with 
an accelerator E). 
Examples of hardeners D) are polyamines with at least two primary and/or 
secondary amino groups, such as aliphatic amines, for example 
propane-1,3-diamine, hexamethylenediamine, diethylenetriamine, 
triethylenetetramine or 2,2,4-trimethylhexane-1,6-diamine; cycloaliphatic 
amines, for example bis(4-aminocyclohexyl)methane or 
3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine); aromatic 
amines, for example bis(4-aminophenyl)methane, aniline/formaldehyde 
resins, bis(4-aminophenyl) sulfone, bis(4-aminophenyl)methane or 
2,2-bis(4-aminophenyl)propane; araliphatic amines, such as 
xylylenediamine; or heterocyclic amines. 
Other examples of hardeners D) are polyaminoamides, for example those 
derived from aliphatic polyamines and dimerized or trimerized fatty acids; 
amides, including substituted ureas, in particular ureas with aromatic 
radicals, such as N-(4-chlorophenyl)-N,N'-dimethylurea, 
N-(3-chloro-4-methylphenyl)-N,N',-dimethylurea (chlortoluron), 
N-(2-hydroxyphenyl)-N,N'-dimethylurea or 2,4-bis(N,N-dimethylureido) 
toluene; polyphenols, such as resorcinol, hydroquinone, 
2,2-bis(4-hydroxyphenyl)-propane (bisphnol A) and novolaks based on 
monophenols or polyphenols, such as phenol or cresols, and aldehydes, such 
as formaldehyde, acetaldehyde or chloral; polythiols, such as the 
polythiols commercially available under the name "Thiokols.RTM."; or 
polycarboxylic acids and in particular the anhydrides thereof, for example 
phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic 
anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, 
pyromellitic anhydride, benzophenone-3,3',4,4'-tetracarboxylic dianhydride 
and the acids of the above-mentioned anhydrides, as well as isophthalic 
acid and terephthalic acid. 
It is also possible to use hardeners having a catalytic action, such as 
tertiary amines, e.g. 2,4,6-tris(dimethylaminomethyl)phenol; Mannich based 
or imidazoles, such as 2-methylimidazole, 2-phenylimidazole, 
2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole or 
1-cyanoethyl-2-methylimidazole; tin salts of alkanoic acids, for example 
tin octoate; or Friedel-Crafts catalysts, for example boron trifluoride 
and boron trichlordie and the complexes and chelates thereof which can be 
obtained by reacting boron trifluoride or boron trichloride with e.g. 
1,3-diketones, amines or ethers. 
Other suitable hardeners are amidines, for example dicyandiamide or 
1-cyano-3-(lower alkyl)guanidines such as the 3-methyl, 3,3-dimethyl or 
3,3-diethyl derivatives. 
Examples of curing accelerators E) are tertiary amines, the salts thereof 
or quaternary ammonium compounds, such as benzyldimethylamine, 
2,4,6-tris(dimethylaminomethyl)phenol, 4-aminopyridine or 
tetramethylammonium chloride; or the above-mentioned imidazoles or 
substituted ureas. 
The properties of the cured end product can be varied according to the 
proportions of components A) and B). 
The following percentages relate in each case to the total weight of 
components A), B) and C). 
If it is desired to have products of high strength, high glass transition 
temperature, high peel strength, high impact strength and high resistance 
to crack propagation (cracking resistance), the proportions of components 
A) and B) should not normally exceed 60% by weight. Such systems are 
normally heterogeneous. The lower limit depends on the desired properties, 
for example the peel strength. Under normal circumstances, components A) 
and B) should account for more than 5% by weight, preferably more than 10% 
by weight. 
If, on the other hand, it is desired to have products with the highest 
possible flexibility, components A) and B) should be present in 
proportions of at least 40% by weight, preferably more than 60% by weight. 
If component A) and/or B) has been modified by the formation of an adduct 
with an epoxy resin, a separate component C) is not absolutely necessary. 
The weight of A) to B) can be varied within wide limits. As regards the 
range of A) to B), 50:1 to 1:50 is preferred, 20:1 to 1:10 is especially 
preferred and 5:1 to 1:5 is most preferred. 
The proportions of epoxy resin C) and of the total amount of A), B) and C) 
can also be varied within wide limits. For cured products of high 
flexibility, smaller amounts of C), for example 10 to 30% by weight, will 
generally by used, it also being possible for component C) to be present 
as an adduct with A), whereas for cured products of high strength, larger 
amounts of C), for example 50 to 95% by weight, preferably 60 to 80% by 
weight, will generally be used. 
The compositions of the invention can be cured at low temperatures, for 
example at room temperature, or with the application of heat. 
The curing temperatures in the case of hot curing are generally between 
80.degree. and 250.degree. C., preferably between 100.degree. and 
180.degree. C. 
If desired, curing can also be carried out in two stages, e.g. by 
interrupting the curing process or, if using a hardener for higher 
temperatures, by allowing the curable mixture to cure partly at lower 
temperatures. The resulting products are precondensation products which 
are still fusible and soluble (so-called "B-stage resins") and are 
suitable e.g. for compression moulding compounds, sintering powders or 
prepregs. 
Preferred systems are hot-curable systems in which components A), B) and C) 
are used in combination with primary and/or secondary aromatic amines or 
with amidines, in particular dicyandiamide, as hardeners D); accelerators, 
in particular urea-based accelerators, can be incorporated if necessary. 
Component B) used in this embodiment is in particular a compound of formula 
I in which Y is --OH, --OCN, 
##STR12## 
or an adduct of an epoxy resin C) and a compound of formula I where 
Y=--OH. 
Compositions containing components A) and B) in which component B) contains 
compounds of formula I with Y=--NHR.sup.3 are preferably used for the 
manufacture of epoxy-based two-component adhesives which cure at room 
temperature. This is done by combining the composition containing 
components A) and B) with epoxy resin C) in a manner known per se, just 
before processing. 
If desired, reactive diluents can be added to the curable mixtures in order 
to reduce the viscosity further, examples of such diluents being styrene 
oxide, butyl glycidyl ether, 2,2,4-trimethylpentyl glycidyl ether, phenyl 
glycidyl ether, cresyl glycidyl ether or glycidyl esters of synthetic, 
highly branched, mainly tertiary aliphatic monocarboxylic acids. 
Other conventional additives which the mixtures of the invention can also 
contain are plasticizers, extenders, fillers and reinforcing agents, for 
example coal tar, bitumen, textile fibres, glass fibres, asbestos fibres, 
boron fibres, carbon fibres, mineral silicates, mica, quartz powder, 
hydrated aluminium oxide, bentonites, wollastonite, kaolin, silicic acid 
aerogel, metal powders, e.g. aluminium powder or iron powder, pigments and 
dyes, such as carbon black, oxide pigments and titanium dioxide, 
flameproofing agents, thixotropic agents, levelling agents (which can also 
be used in some cases as mould release agents), such as silicones, waxes 
and stearates, or adhesive primers, antioxidants and light stabilizers. 
When curing with phenols or aromatic amines, it is preferred to add 
temperature-resistant thermoplasts, in particular aromatic polyethers, 
such as poly(2,6-dimethylphenol), polyether-sulfones, polyether-imides or 
polyether-ketones. 
The mixtures of the invention can be used quite generally for the 
manufacture of cured products and can be used in the formulation 
appropriate to the particular field of application for the manufacture of 
adhesives, self-adhesive films, patches, sealing compounds, varnishes or 
matrix resins. 
The invention further relates to the use of the curable mixtures for the 
above-mentioned purposes and to the use of the compositions of components 
A) and B) as flexibilizers for epoxy resins. 
The cured products are distinguished by the advantageous properties 
described in the introduction. The invention therefore further relates to 
the products obtainable by curing compositions containing A), B) and C) or 
containing adducts of A) and/or B) and epoxy resins.

The following Examples will serve to illustrate the invention. Amounts are 
given in parts by weight unless stated otherwise. 
A) Preparation of the prepolymers 
EXAMPLE 1 
Under nitrogen, 270 g of ethyl p-hydroxybenzoate and 893 g of 
bis(3-aminopropyl)polytetrahydrofuran (Mn=1100) are heated at 220.degree. 
C. for 8 hours in the presence of 4 g of dibutyl-tin oxide, ethanol being 
distilled off. Yield: 1056 g of a viscous resin giving the following 
analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =42,880 mPas; 
phenol content: 1.38 val/kg; 
molecular weight (GPC, in THF): Mn=1680; Mw/Mn=2.2. 
EXAMPLE 2 
Under nitrogen, 33.2 g of ethyl p-hydroxybenzoate and 210 g of 
bis(3-aminopropyl)polytetrahydrofuran (Mn=2100) are heated at 220.degree. 
C. for 8 hours in the presence of 0.5 g of dibutyl-tin oxide, ethanol 
being distilled off. Yield: 226 g of a viscous resin giving the following 
analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =12,000 mPas; 
phenol content: 0.72 val/kg; 
molecular weight (GPC, in THF): Mn=2810; Mw/Mn=2.6. 
EXAMPLE 3 
Under nitrogen, 1000 g of polytetrahydrofuran with two hydroxyl end groups 
(Mn=1000) and 332 g of ethyl p-hydroxybenzoate are heated at 220.degree. 
C. for 10 hours in the presence of 5 g of dibutyl-tin oxide, ethanol being 
distilled off. Yield: 1236 g of a viscous resin giving the following 
analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =6880 mPas; 
phenol content: 1.54 val/kg: 
molecular weight (GPC, in THF): Mn=1560; Mw/Mn=2.3. 
EXAMPLE 4 
Under nitrogen 110 g of bis(3-aminopropyl) polytetrahydrofuran (Mn=1000) 
and 32.6 g of isatoic anhydride are reacted at 120.degree. C. for 6 hours. 
Yield: 127 g of a viscous resin giving the following analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =6320 mPas; 
phenol content: 1.16 val/kg; 
molecular weight (GPC, in THF): Mn=1600; Mw/Mn=2.1 
EXAMPLE 5 
Under nitrogen, 500 g of polypropylene glycol with two amino end groups 
(Mn=2000) and 83 g of ethyl p-hydroxybenzoate are heated at 220.degree. C. 
for 6 hours in the presence of 2 g of dibutyl-tin oxide. Yield: 548 g of a 
viscous resin giving the following analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =2560 mPas; 
phenol content: 0.73 val/kg. 
EXAMPLE 6 
Under nitrogen, 500 g of polypropylene glycol with three amino end groups 
(Mn=5000) and 50 g of ethyl p-hydroxybenzoate are heated at 210.degree. C. 
for 6 hours in the presence of 2 g of dibutyl-tin oxide. Yield: 524 g of a 
viscous resin giving the following analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =3360 mPas; 
phenol content: 0.44 val/kg. 
EXAMPLE 7 
Under nitrogen, 730 g of bisphenol A diglycidyl ether (epoxy content: 5.4 
val/kg), 200 g of acrylonitrile/butadiene copolymer with carboxyl end 
groups (acrylonitrile content: 26%, acid number: 32 mg of KOH/g), 64 g of 
bisphenol A and 5 g of triphenylphosphine are heated at 130.degree. C. for 
3 hours until a viscous resin with an epoxy content of 3.3 val/kg and an 
Epprecht viscosity of 130,000 mPas (40.degree. C.) has formed. 
EXAMPLE 8 
A mixture of 150 g of the prepolymer according to Example 3 and 150 g of 
bisphenol A diglycidyl ether (epoxy content: 5.4 val/kg) is heated at 
140.degree. C. for 2 hours in the presence of 4.5 g of triphenylphosphine 
until a viscous resin giving the following analytical data has formed: 
epoxy content: 1.8 val/kg; 
viscosity (25.degree. C.): 44,800 mPas. 
EXAMPLE 9 
A mixture of 500 g of the polytetrahydrofuran with two 4-hydroxybenzoate 
end groups according to Example 3, 214 g of dimethylformamide, 170 g of 
finely ground potassium carbonate and 275 g of epichlorohydrin is heated 
at 60.degree. C. for 5 hours. The salt is then filtered off, the filtrate 
is concentrated on a rotary evaporator at 80.degree. C. under vacuum, 1.5 
l of diethyl ether are added and the mixture is washed with 500 ml of 
deionized water. After the ether phase has been dried over sodium sulfate, 
the solvent is stripped off under vacuum. Yield: 470 g of a viscous resin 
giving the following analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =4320 mPas; 
epoxy content: 0.95 eq/kg; 
molecular weight (GPC, in THF): Mn=1480; Mw/Mn=3.6. 
EXAMPLE 10 
93.2 g of triethylamine in 500 ml of toluene are added at 0.degree. C., 
over 30 minutes, to a mixture of 500 g of the polytetrahydrofuran with two 
4-hydroxybenzoate end groups according to Example 3 and 66 g of cyanogen 
bromide in 1 l of toluene and the resulting mixture is stirred at 
0.degree. C. for a further 3 hours. It is then filtered and the organic 
phase is washed with 750 ml of water. After drying over sodium sulfate, 
the solvent is removed on a rotary evaporator at 60.degree.-70.degree. C. 
under vacuum. Yield: 440 g of a viscous resin giving the following 
analytical data: 
viscosity (according to Epprecht): .eta..sub.25 =8960 mPas; 
molecular weight (GPC, in THF): Mn=1210; Mw/Mn=9.7. 
EXAMPLE 11 
A mixture of 1 kg of polytetrahydrofuran with two hydroxyl end groups 
(Mn=1000) and 330 g of ethyl p-aminobenzoate is heated at 220.degree. C. 
for 8 hours in the presence of 4 g of dibutyl-tin oxide, ethanol being 
distilled off. 1250 g of a viscous resin giving the following analytical 
data are isolated: 
viscosity (according to Epprecht): .eta..sub.25 =6080 mPas; amine content: 
1.4 eq/kg; 
molecular weight (GPC, in THF): Mn=1500; Mw/Mn=3.6. 
B) Application Examples 
Study of the cured mixtures 
The mixtures described in the Table below are prepared on a three-roll mill 
and used for bonding degreased sandblasted aluminium of thickness 1.5 mm 
(Avional.RTM.). The test pieces, with an overlap of 1.25 cm.sup.2, are 
heated at 180.degree. C. for 60 minutes in order to cure the mixtures 
described above. The lap shear strength (N/mm.sup.2) is determined 
according to DIN 53283. In some cases, the T-peel is also determined on 
0.8 mm degreased steel according to DIN 53282, with a curing time of one 
hour at 180.degree. C. The results are given in the following Table: 
TABLE 
__________________________________________________________________________ 
Composition and test results for the adhesive mixtures studied 
Example no. 
I II III 
IV V VI VII 
VIII 
IX X XI XII 
XIII 
XIV 
__________________________________________________________________________ 
Diglycidyl ether 
35 35 35 35 35 35 35 35 35 35 -- 35 35 35 
based on bisphenol A 
(epoxy content 5.4 val/kg) 
Butanediol diglycidyl ether 
2,5 
2,5 
2,5 
2,5 
2,5 
2,5 
2,5 
10 10 10 -- 2,5 
2,5 
2,5 
(epoxy content 9.2 val/kg) 
Wollastonite Pl 
15 15 15 15 15 15 15 15 -- -- -- 15 15 15 
Pyrogenic silicic acid 
3,5 
3,5 
3,5 
3,5 
3,5 
3,5 
3,5 
3,5 
2 2 2 3,5 
3,5 
3,5 
Dicyandiamide 4,9 
4,9 
4,9 
4,9 
4,9 
4,9 
4,9 
4,9 
4,8 
4,8 
4,8 
4,9 
4,9 
4,9 
Chlortoluron 0,25 
0,25 
0,25 
0,25 
0,25 
0,25 
0,25 
0,25 
1,0 
1,0 
1,0 
0,25 
0,25 
0,25 
Prepolymer of Example 7 
15 15 15 15 15 15 30 7,5 
15 30 30 15 15 15 
Prepolymer of Example no. 
1 2 3 4 5 6 8 3 3 3 3 9 10 11 
(g) 15 15 15 15 15 15 15 7,5 
15 30 30 15 15 15 
lap shear strength on 
39,0 
35,0 
33,7 
33,7 
35,0 
26,7 
38,7 
35,4 
32,4 
25,5 
6,3 
34,8 
33,0 
28,9 
aluminium (N/mm.sup.2) 
lap shear strength on 
29,9 
28,3 
25,1 
27,4 
27,8 
20,3 
27,9 
n.d. 
n.d. 
n.d. 
n.d. 
26,2 
28,0 
27,3 
steel (N/mm.sup.2) 
T peel on steel (N/mm ) 
3,1 
4,0 
5,4 
5,9 
4,7 
3,0 
4,0 
n.d. 
n.d. 
n.d. 
n.d. 
3,7 
5,2 
4,5 
__________________________________________________________________________ 
n.d. not determined