Hydroxyl terminated polyfunctional epoxy curing agents

A polyglycidyl derivative of an aromatic diamine, aminophenol, or polyphenol and a diglycidyl ether of a bisphenol are reacted with a bisphenol, in the presence of a catalyst at elevated temperature, to yield a reaction product wherein each glycidyl group is effectively endcapped with a moiety containing a free hydroxyl group. The ratio of equivalents of polyglycidyl compound to diglycidyl compound is 1 to 4 to 1 to 1, and of bisphenol to total glycidyl compounds is 1.8 to 1 to 2.4 to 1. Said product is useful for curing solid epoxy resins. The epoxy resins cured by said product have a dense crosslinked network resulting in concomitant superior coating properties especially chemical resistance while maintaining good flexibility.

BACKGROUND OF THE INVENTION 
The instant invention pertains to polyfunctional phenolic hydroxyl 
terminated hardener products and to curable solid epoxy resin compositions 
containing said hardeners. 
The reaction of epoxy resins with phenolic hydroxy-containing compounds in 
the presence of a catalyst is well known in the art. This reaction is 
typified by the reaction of bisphenol A (=BPA or 
4,4'-isopropylidenediphenol) with liquid BPA epoxy resins to form solid 
high molecular weight products. 
U.S. Pat. No. 3,931,109 teaches the termination of basic liquid BPA epoxy 
resins as well as epoxy novolac resins with bisphenol A to give phenolic 
hydroxyl terminated hardeners. 
U.S. Pat. No. 3,931,109 also teaches curable compositions of liquid epoxy 
resins containing a dispersion of a solid phenolic hydroxyl terminated 
hardener therein. 
The instant polyfunctional phenolic hydroxyl terminated hardener products 
are superior to the hardeners described in U.S. Pat. No. 3,931,109 in 
respect to curing solid epoxy resins to cured products with outstanding 
properties particularly in regards to chemical resistance. This is 
especially of value in the field of coatings. 
The products of this invention are useful as curing agents for epoxy 
resins. When these items are combined with di- and polyepoxide resins and 
cured at elevated temperatures (e.g. 180.degree. C.) a dense crosslinked 
network is established which produces superior protective coatings. These 
coatings, when applied by electrostatic techniques and properly cured to 
produce thin films, excel in chemical resistance while maintaining 
flexibility. 
The reason these multifunctional hardeners produce their extremely good 
chemical resistance is through formation of a dense crosslinked reticulum 
in the final cured coating. The difunctional BPA terminated hardeners form 
linear extensions, while the multifunctional BPA terminated curing agents 
produce a web-like structure. This three dimensional network provides the 
tight barrier by which the cured final coating strongly resists any 
chemical attack. 
The reaction of hydroxyl groups with liquid epoxy resins to form higher 
molecular weight epoxy resins is described by H. Lee and K. Neville, 
"Handbook of Epoxy Resins", McGraw Hill, 1967, New York, pp. 2-6 , 2-9. 
Chapter 2 of Lee and Neville's "Handbook of Epoxy Resins" is devoted to 
the "Synthesis of Glycidyl-Type Epoxy Resins". This chapter describes the 
synthesis of high molecular weight epoxy resins based on many types of 
alcohols. 
U.S. Pat. No. 4,322,456 discloses powder coating compositions consisting of 
an epoxy resin, a phenolic hardener and a catalyst for effecting reaction 
between said resin and said hardener. 
The instant polyfunctional phenolic hydroxyl terminated hardener products 
are superior to the hardeners described in U.S. Pat. No. 4,322,456 in 
respect to curing solid epoxy resins to cured products with outstanding 
properties particularly in respect to chemical resistance while 
maintaining flexibility. 
U.S. Pat. No. 4,288,565 pertains to epoxy molding compositions wherein 
triphenols such as 1,1,3-tris(4-hydroxyphenyl)propane are used as the 
phenolic hardener component. While both the instant hardeners and those of 
this reference have three or more phenolic groups per molecule, the 
remainder of the respective hardener molecules differ widely. The prior 
art hardener is a relatively small molecule with the terminal phenolic 
hydroxy groups attached to the backbone trimethylene-(=propane) chain at 
very close intervals. While this does not interfere with the hardening 
efficacy of the molecule, the cured epoxy resin is a relatively rigid and 
inflexible structure due to the high crosslink density (nearness together 
of the original phenolic hydroxyl groups). 
By contrast the instant hardeners, wherein the terminal phenolic hydroxyl 
groups are relatively far removed from one another with a relatively bulky 
linking group therebetween, permit good curing since the efficacy of the 
phenolic hydroxyl groups is undiminished. However, a lower crosslink 
density is obtained leading to a concomitant increase in flexibility 
without loss of chemical resistance. 
The preponderance of hydroxyl groups present in the instant hardeners also 
allows for improved adhesion of epxoy resin cured thereby. 
OBJECTS OF THE INSTANT INVENTION 
One object of the instant invention is a polyfunctional phenolic hydroxyl 
terminated product useful as hardener in the curing of solid epoxy resins. 
A second object of the instant invention is a curable composition 
comprising a solid epoxy resin and a polyfunctional phenolic hydroxyl 
terminated hardener of this invention. 
Still another object of this invention is a cured composition having 
superior properties prepared by curing a composition comprising a solid 
epoxy resin and a polyfunctional phenolic hydroxyl terminated hardener of 
this invention. 
DETAILED DISCLOSURE 
The instant invention pertains to a polyfunctional phenolic hydroxyl 
terminated hardener product, useful in the curing of epoxy resins, which 
is the reaction product of 
(a) a polyglycidyl compound of the formula I, II, III or IV. 
##STR1## 
wherein 
T.sub.1 is 1,2-phenylene, 1,3-phenylene, 1,4-phenylene or 
##STR2## 
where Q is alkylene of 1 to 6 carbon atoms, alkylidene of 2 to 6 carbon 
atoms, --SO.sub.2 --, --SO--, --S--, --S--S--, --O-- or --CO--, 
T.sub.2 is 1,2-phenylene, 1,3-phenylene or 1,4-phenylene, 
T.sub.3 is 1,2,3-benzenetriyl, 1,2,4-benzenetriyl, 1,3,5-benzenetriyl or 
##STR3## 
T.sub.4 is 
##STR4## 
where G.sub.1 and G.sub.2 are independently alkyl of 1 to 6 carbon atoms 
or are together alkylene of 4 to 5 carbon atoms, and 
(b) a diglycidyl compound of the formula 
EQU glycidyl--O--E--O--glycidyl 
where 
E is 1,2-phenylene, 1,3-phenylene, 1,4-phenylene or L 
where L is a direct bond, alkylene of 1 to 6 carbon atoms or alkylidene of 
2 to 6 carbon atoms, 
wherein the ratio of equivalents of polyglycidyl compound (a) to diglycidyl 
compound (b) is from 1 to 4 to 1 to 1, with 
(c) a bisphenol of the formula 
EQU HO--E.sub.1 --OH 
where E.sub.1 has the same definitions as E, but is independent of E, 
wherein the ratio of equivalents of bisphenol component (c) to the total 
equivalents of glycidyl compounds (a) plus (b) is from 1.8 to 1 to 2.4 to 
1, and where each glycidyl group is effectively endcapped with a moiety 
containing a free phenolic hydroxyl group by reaction of components (a) 
and (b) with (c) in the presence of an effective amount of a catalyst for 
promoting said reaction at a temperature between 120.degree. and 
300.degree. C. 
Another aspect of the instant invention relates to curable compositions 
comprising 
(A) a solid epoxy resin having more than one 1,2-epoxy group, 
(B) a polyfunctional phenolic hydroxyl terminated epoxy hardener product of 
the instant invention or mixtures thereof, and 
(C) a catalytic amount of a catalyst effective in causing reaction between 
the epoxy groups of (A) and the phenolic hydroxyl groups of (B), 
wherein the epoxy resin (a) and the hydroxyl terminated hardener (b) are 
employed in such quantities as to provide a final cured product exhibiting 
both flexibility and chemical resistance. 
These curable compositions have an equivalent ratio of epoxy groups of the 
epoxy resin of component (A) to phenolic hydroxyl groups of the hardener 
product of component (B) in the range of 1:0.4 to 1:1.2; preferably of 
1:0.5 to 1:0.8; and most preferably of 1:0.65 to 1:0.75. 
A further aspect of the instant invention pertains to cured epoxy resin 
compositions prepared from the curable compositions of the instant 
invention. Such cured compositions find utility in a host of end-use 
applications including moldings and electrical uses, but it is 
particularly in the field of coatings that the instant cured compositions 
find their most important use. The properties of such cured coatings are 
excellent, especially in regards to chemical resistance, flexibility and 
adhesion. 
The polyfunctional phenolic hydroxyl terminated hardeners of the instant 
invention are prepared by reaction of a polyglycidylated aromatic diamine, 
aminophenol, polyphenol with functionality more than 2 or heterocyclic 
nitrogen compound and a diglycidyl ether of a bisphenol with a bisphenol 
in such amounts that about two equivalents of bisphenol are reacted with 
each equivalent of glycidyl moiety leading to the instant compounds 
containing phenolic end groups on each original glycidyl moiety. 
These polyglycidylated compounds (a) are in many cases items of commerce or 
may be prepared in a conventional glycidylation reaction with 
epichlorohydrin and the commercially available aromatic diamines, 
aminophenols, polyphenols or heterocyclic nitrogen compounds. 
T.sub.1 is derived from aromatic diamines such as o-, m- or 
p-phenylenediamine or the diamines of the formula 
##STR5## 
where Q is alkylene of 1 to 6 carbon atoms, alkylidene of 1 to 6 carbon 
atoms, --SO.sub.2 --, --SO--, --S--, --S--S--, --O-- or --CO--. 
Preferably T.sub.1 is 1,3-phenylene, 1,4-phenylene or 
##STR6## 
where Q is methylene or --O--. Most prefereably T.sub.1 is 
##STR7## 
where Q is methylene. 
T.sub.2 is derived from o-, m- and p-aminophenols. Preferably T.sub.2 is 
1,4-phenylene. 
T.sub.3 is derived from polyfunctional phenols having a functionality of 3 
or 4. These polyphenols include phloroglucinol, pyrogallol, 
1,2,4-benzenetriol and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane. 
Preferably T.sub.3 is 
##STR8## 
T.sub.4 is derived from nitrogen heterocyclic compounds including 
triglycidyl isocyanurate or triglycidyl bis-hydantoins of the formula 
##STR9## 
where G.sub.1 and G.sub.2 are independently alkyl of 1 to 6 carbon atoms, 
preferably methyl, or G.sub.1 and G.sub.2 are together alkylene of 4 to 5 
carbon atoms. 
Preferably T.sub.4 is derived from triglycidyl isocyanurate. 
The diglycidylated derivatives of bisphenols are also items of commerce or 
may be prepared by the conventional glycidylation reaction with 
epichlorohydrin and commercially available bisphenols. 
The diglycidylated compounds (b) have the formula 
glycidyl--O--E--O--glycidyl and are derived, for example, from catechol, 
resorcinol, hydroquinone, o,o'-biphenol, p,p'-biphenol, 
bis(2-hydroxyphenyl)methane, bis(4-hydroxyphenyl)methane and 
2,2-bis(4-hydroxyphenyl)propane. E is thus 1,2-phenylene, 1,3-phenylene, 
1,4-phenylene or 
##STR10## 
where L is a direct bond, alkylene of 1 to 6 carbon atoms or alkylidene of 
2 to 6 carbon atoms. 
Preferably E is 
##STR11## 
where L is isopropylidene. 
The bisphenols (c) have the formula 
EQU HO--E.sub.1 --OH 
where E.sub.1 has the same definitions as E given above, but E and E.sub.1 
are independent of one another. Examples of suitable bisphenols are 
delineated supra. 
The reaction of the polyglycidylated and diglycidylated compounds with the 
bisphenol to make the instant polyfunctional phenolic hydroxyl terminated 
hardener is carried out in the presence of a catalytic amount of a 
catalyst effecting the reaction between an epoxy or glycidyl group and a 
phenolic hydroxyl group. 
Suitable catalysts which are employed to effect the reaction between the 
glycidyl group and the phenolic hydroxyl groups include the phosphonium 
salts of organic and inorganic acids, imidazoles, imidazolines, quaternary 
ammonium compounds and the like. Any catalyst which will effectively 
promote the reaction between a 1,2-epoxide group and a phenolic hydroxyl 
group can suitably be employed in the present invention. 
The catalysts are generally employed in quantities of from about 0.001% to 
about 10% and preferably from about 0.05% to about 5% by weight based upon 
the combined weight of the reactants, i.e. the weight of 
glycidyl-containing compound plus the weight of the phenolic 
hydroxyl-containing compound. 
The inorganic and organic phosphonium compounds which are employed in the 
process of the present invention, as catalysts, include phosphonium salts 
of an acid, acid ester or ester of an element selected from the group 
consisting of carbon, nitrogen, phosphorus, sulfur, silicon, chlorine, 
bromine, iodine and boron which are represented by the general formula: 
##STR12## 
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently selected 
from the group consisting of hydrogen, aliphatic hydrocarbon radicals 
containing from about 1 to 20 carbon atoms, aromatic hydrocarbon radicals, 
alkyl substituted aromatic hydrocarbon radicals and radicals represented 
by the formula --R.sub.5 --Y wherein R.sub.5 is an aliphatic hydrocarbon 
radical having from about 1 to about 20 carbon atoms and Y is a member 
selected from the group consisting of Cl, Br, I, NO.sub.2, H and OH and 
where X is the anion portion of an acid, ester or acid ester of an element 
selected from carbon, nitrogen, phosphorus, sulfur, silicon, chlorine, 
bromine, iodine and boron and wherein m is the valence of the anion X. 
Particularly suitable catalysts include ethyltriphenyl phosphonium iodide, 
ethyltriphenyl phosphonium chloride, ethyltriphenyl phosphonium 
thiocyanate, ethyltriphenyl phosphonium acetate acetic acid complex, 
tetrabutyl phosphonium iodide, tetrabutyl phosphonium bromide, and 
tetrabutyl phosphonium acetate acetic acid complex. 
These and other phosphonium catalysts are more fully described in U.S. Pat. 
No. 3,477,990 and U.S. Pat. No. 3,341,580. 
Suitable imidazoles which may be employed as catalysts in the present 
invention include, for example, 2-styrylimidazole, 
1-benzyl-2-methylimidazole, 2-methylimidazole, 2-butylimidazole, mixture 
thereof and the like. These and other suitable catalysts are disclosed in 
Lee and Neville, "Handbook of Epoxy Resins", McGraw Hill, 1967, New York, 
pp. 11-14. 
The imidazole catalysts are particularly preferred in the preparation of 
the instant hardeners. 
It is noted that the catalysts described above which are useful in the 
preparation of the instant hardeners are the very same catalysts which may 
be used as component (C) in the curable compositions of the instant 
invention. 
These curable compositions comprise 
(A) a solid epoxy resin having more than one 1,2-epoxy group, 
(B) a polyfunctional phenolic hydroxyl terminated epoxy hardener of this 
invention, and 
(C) a catalytic amount of a catalyst effective in causing reaction between 
the epoxy groups of (A) and the phenolic hydroxyl groups of (B). 
Suitable solid epoxy resins which are employed as component (a) in the 
present invention include the aromatic based epoxy resins represented by 
the following general formulae including mixtures thereof. 
##STR13## 
wherein A is a divalent hydrocarbon group having from about 1 to about 6 
carbon atoms, 
##STR14## 
each X is independently hydrogen, chlorine or bromine, and n has an 
average value of from about 1 to about 12 and preferably from about 3 to 
about 7. 
##STR15## 
wherein R is hydrogen or an alkyl group having from about 1 to about 4 
carbon atoms, n has an average value of from about 0 to about 8, and X is 
hydrogen, chlorine, bromine or a lower alkyl group having from 1 to about 
4 carbon atoms. 
The epoxy resins employed in the present invention may be prepared by any 
of the well known methods such as the reaction of a bisphenolic compound 
with an epihalohydrin in the presence of suitable catalysts or by the 
reaction of a liquid polyepoxide with a bisphenol in the presence of such 
compounds as quaternary ammonium compounds, tertiary amines, phosphonium 
compounds and the like. These methods are discussed in Chapter 2 of 
Handbook of Epoxy Resins by Lee and Neville, McGraw Hill Book Co., 1967 
and in U.S. Pat. No. 3,477,990. 
Any solid aromatic based epoxy resin which has more than one 1,2-epoxy 
group is suitable for use in the present invention. 
Suitable hardeners which may be used as component (B) in the instant 
invention are the polyfunctional phenolic hydroxyl terminated hardeners 
described above and being the reaction product of a polyglycidyl compound 
of formula I, II, III or IV, a diglycidylated compound of formula 
glycidyl--O--E--O--glycidyl, and a bisphenol of formula HO--E.sub.1 --OH. 
Preferably, component (B) is a hardener derived from a polyglycidyl 
compound of formula I, II or III where T.sub.1 is 
##STR16## 
T.sub.2 is 1,4-phenylene, T.sub.3 is 
##STR17## 
from a diglycidyl compound and from a bisphenol where E and E.sub.1 are 
respectively both 
##STR18## 
Those skilled in the art will readily recognize the ratio of epoxy compound 
to phenolic hydroxyl-containing compound required to produce a product of 
desired molecular weight or simple experimentation can be employed to 
arrive at the desirable ratio for any desired molecular weight. 
The instant curable compositions may find utility in a host of end-use 
applications including moldings and electrical uses. However, it is in the 
field of powder coatings that these curable compositions find their most 
advantageous use. 
The instant curable compositions may contain, if desired, dyes, pigments, 
flow aids and other suitable additives. The compositions in powder form 
may be used to coat suitable substrates by depositing said powder on the 
substrate followed by subsequent heating of the powder coated substrate to 
effect the catalyzed curing reaction between the solid epoxy resin, 
component (A), and the polyfunctional phenolic hydroxyl terminated 
hardener, component (B), in the presence of the catalyst, component (C). 
The curing reaction is effected by heating the coated substrate to effect 
the reaction between (A) and (B) usually between about 120.degree. to 
about 300.degree. C. and preferably from about 140.degree. C. to about 
300.degree. C. for from about 10 seconds to about 60 minutes and 
preferably from about 10 seconds to about 30 minutes or applying said 
composition to a substrate preheated to a temperature of from about 
120.degree. to about 300.degree. C., preferably from about 140.degree. C. 
to about 300.degree. C., the cure thereby being obtained by the transfer 
of heat from the heated substrate to the coating. 
The substrates which are employed in the process of the present invention 
are metallic substrates such as steel, aluminum, etc. but any substrate 
which will withstand temperatures of at least about 130.degree. C. can be 
employed. 
Pigments, fillers, dyes, flow control agents and other modifier compounds 
may also be employed in the coating compositions employed in the coating 
process or method of the present invention. 
In the present invention, the coated substrates are subjected to 
temperatures which will effect the reaction between the epoxy resin and 
the phenolic hydroxyl containing compound. The time employed is of course, 
dependent upon the temperature, the mass of the coated substrate, etc. For 
example, thin metallic substrates subjected to a temperature of 
300.degree. C. would require only a few seconds to effect and complete the 
reaction whereas automobile bodies subjected to a temperature of 
120.degree. C. would require upwards to 60 minutes to effect and complete 
the reaction between the epoxy resin and the phenolic hydroxyl-containing 
compound. 
The coatings of the present invention can be employed as coatings for such 
articles as automobiles, machinery, appliances, containers and the like. 
The following examples are presented for the purpose of illustration only 
and are not to be construed to limit the nature or scope of the instant 
invention in any manner whatsoever.

PREATION OF THE HYDROXYL TERMINATED CURING AGENTS 
Example 1 
A three-necked round-bottomed flask equipped with a heating mantle, 
mechanical stirrer, thermometer, and nitrogen inlet tube is charged with 
66.5 g (0.627 eq.) of N,N,O-triglycidyl-p-aminophenol, 141.25 g (0.743 
eq.) of 2,2-bis(4-glycidyloxyphenyl)propane (or the diglycidyl ether of 
bisphenol A, equivalent weight is 190), 285 g (2.5 eq.) of bisphenol A, 
and 40 ppm of 2-isopropylimidazole. 
The flask and contents are heated to 100.degree. C. and held at that 
temperature for one hour, after which the temperature is increased to 
125.degree. C. and held for another hour. The 25.degree. C. increments 
with a subsequent hold at temperature for one hour are continued until the 
reaction temperature of 175.degree. C. is reached. The flask and contents 
are held at 175.degree. C. for two hours. The flask is discharged after 
two hours and the reaction product is cooled to room temperature. The 
hydroxyl terminated product is then characterized by a Gardner-Holdt 
viscosity at 25.degree. C. of U-V (ASTM D-445), a melting point of 
102.degree.-103.degree. C., and a theoretical combining weight of 444 g. 
This product is designated AA. 
Example 2 
Using the general procedure of Example 1, 162.1 (1.29 eq.) of 
N,N,N',N'-tetraglycidyl-4,4-diaminodiphenylmethane, 293.6 g (1.54 eq.) of 
2,2-bis(4-glycidyloxyphenyl)propane, 768.6 g (6.74 eq.) of bisphenol A, 
and 40 ppm of 2-isopropylimidazole are reacted. The addition product is 
characterized by an ICl viscosity at 200.degree. C. of 720 cP, a melting 
point of 90.degree. C., and a theoretical combining weight of 308 g. 
This product is designated BB. 
Example 3 
Using the general procedure of Example 1, 112.2 g. (0.60 eq.) of 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane, 152.0 g (0.80 eq.) of 
2,2-bis(4-glycidyloxyphenyl)propane, 364.8 g (3.2 eq.) of bisphenol A, and 
40 ppm of 2-isopropylimidazole are reacted. The addition product is 
characterized by an ICI viscosity at 200.degree. C. of 1027 cP, a melting 
point of 100.degree. C. and a theoretical combining weight of 349 g. 
This addition product is designated CC. 
Example 4 
Using the general procedure of Example 1, 122 g (1 eq.) of cresol novolac 
resin hardener HT 9490 (n=3.1), 228 g (2 eq.) of bisphenol A, 188 g (1 
eq.) of 2,2-bis(4-glycidyloxyphenyl)propane, and 40 ppm of 
2-isopropylimidazole are reacted. The addition product is characterized by 
a Gardner-Holdt viscosity at 25.degree. C. of U, a melting point of 
95.degree.-96.degree. C. and a theoretical combining weight of 269 g. 
This addition product is designated DD. 
PREATION OF CURED EPOXY RESINS USING THE HYDROXYL TERMINATED CURING 
AGENTS 
Example 5 
The product AA, prepared in Example 1, is used as a multifunctional hydroxy 
terminated curing agent in an epoxy resin formulation as is seen below. 
______________________________________ 
Component Material g 
______________________________________ 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
44.1 
AA 88.2 
Flow Aid ("MODAFLOW", Monsanto)* 
2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
*"MODAFLOW" flow control agent or flow aid is a poly(2ethylhexyl acrylate 
sold by Monsanto. 
This formulation is 2-roll milled at 70.degree. C. for 6 minutes. The melt 
mixed formulation is then cooled, ground, sieved through a 140 mesh screen 
(105 microns maximum size), and applied by electrostatic techniques to 
cold rolled steel panels. These coated test panels are then tested for 
their physical characteristics as is seen in Example 14. 
This formulation is designated EE. 
Example 6 
As a control, a difunctional hydroxy terminated curing agent, similar to 
those described in U.S. Pat. No. 3,931,109, is used as a curing agent in 
an epoxy resin formulation. The difunctional curing agent is prepared by 
the reaction of two equivalents of bisphenol A with one equivalent of 
2,2-bis(4-glycidyloxyphenyl)propane and is designated DFCA. 
The epoxy resin control formulation is as follows. 
______________________________________ 
Component Material g 
______________________________________ 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
78.75 
DFCA 55.18 
Flow Aid 1.125 
Red Iron Oxide 15.0 
______________________________________ 
This formulation is processed and applied as in Example 5. The resulting 
coated panels are then used for testing of physical characteristics as 
seen in Examples 14 and 18. 
This formulation is designated FF. 
EXAMPLE 7 
Product AA, prepared in Example 1, is formulated with a commercially 
available solid bisphenol A-based epoxy resin GT 7013. The formulation is 
as follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 50.5 
AA 27.5 
Flow Aid ("MODAFLOW") 
1.5 
2-methylimidazole 0.5 
Red Iron Oxide 15.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Example 
16. 
This formulation is designated GG. 
EXAMPLE 8 
Product DFCA, described in Example 6, is formulated with a commercially 
available solid bisphenol A-based epoxy resin GT 7013. The formulation is 
as follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 57.4 
DFCA 21.1 
Flow Aid ("MODAFLOW") 
1.5 
Red Iron Oxide 15.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Examples 
16, 17 and 19. 
This formulation is designated HH. 
EXAMPLE 9 
Product BB, prepared in Example 2, is formulated in combination with a 
commercially available solid bisphenol A-based epoxy resin GT 7013. The 
formulation is as follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 90.8 
BB 41.7 
Flow Aid ("MODAFLOW") 
2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Examples 
17. 
This formulation is designated II. 
EXAMPLE 10 
Product CC, prepared in Example 3, is formulated in combination with 
commercially available solid epoxy resin 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane. The formulation is as 
follows: 
______________________________________ 
Component Material g 
______________________________________ 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
46.2 
CC 86.25 
Flow Aid ("MODAFLOW") 2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Examples 
18. 
This formulation is designated JJ. 
EXAMPLE 11 
Product DD, prepared in Example 4, is formulated in combination with 
commercially available solid bisphenol A-based epoxy resin GT 7013. The 
formulation is as follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 100.0 
DD 39.0 
Flow Aid ("MODAFLOW") 
2.5 
2-methylimidazole 0.3 
TiO.sub.2 28.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Example 
19. 
This formulation is designated KK. 
EXAMPLE 12 
Product AA, prepared in Example 1, is formulated in combination with 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane and the commercially available 
solid bisphenol A-based epoxy resin GT 7013. The formulation is as 
follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 26.5 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
53.25 
AA 56.6 
Flow Aid ("MODAFLOW") 2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
The formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Example 
15. 
This formulation is designated LL. 
EXAMPLE 13 
A formulation based on the difunctional DFCA curing agent, described in 
Example 6, is formulated with 1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
and solid bisphenol A-based epoxy resin GT 7013. The formulation is as 
follows: 
______________________________________ 
Component Material g 
______________________________________ 
GT 7013 21.75 
1,1,2,2-tetrakis(p-glycidyloxyphenyl)ethane 
43.5 
DFCA 57.2 
Flow Aid ("MODAFLOW") 2.25 
Red Iron Oxide 15.0 
______________________________________ 
This formulation is processed and applied as in Example 5 and the resulting 
coated panels are tested for physical characteristics as seen in Example 
15. 
This formulation is designated MM. 
TESTING OF EPOXY RESINS CURED WITH HYDROXYL TERMINATED CURING AGENTS 
Chemical resistance testing is conducted at both room temperature 
(23.degree. C.) and at elevated temperatures (refluxing temperatures for 
various solvents). Sand blasted cold rolled steel panels and 1.27 cm round 
stock are the substrates for the testing. The films range in thickness 
from 3 to 4 mils (0.076 to 0.102 mm) on the panels and 12 to 16 mils 
(0.305 to 0.406 mm) on the rods. The substrates are powder coated by 
electrostatic spray techniques at room temperature for the thinner films 
and at 200.degree. C. for the thicker films. 
In order to demonstrate the superiority of the products of this invention, 
aggressive solvents and elevated temperatures are used. Some or all of the 
following solvents are employed to demonstrate the utility of the 
invention: 
Acetic acid (10%) 
Methyl ethyl ketone (MEK) 
Ethanol 
Methylene chloride 
Acetone 
Refluxing 10% sulfuric acid 
Refluxing sodium hydroxide solution (pH=13.5) 
Boiling water 
Refluxing MEK 
Failures are evidenced by blister formation, delamination, softening to 
substrate, or total destruction of the coating. 
EXAMPLE 14 
______________________________________ 
PHYSICAL TEST RESULTS 
______________________________________ 
Formulation EE FF (control) 
Contains AA DFCA 
Gel @ 171.degree. C. 
44 sec. 85 sec. 
Cure Schedule 
30 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 3.3 to 3.5 mils 
3.0 to 3.2 mils 
(0.084 to 0.089 mm) 
(0.076 to 0.081 mm) 
Closed Direct Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Mandrel Bend Pass 1/2 inch Pass 1/8 inch 
(12.7 mm) (3.2 mm) 
______________________________________ 
______________________________________ 
CHEMICAL TEST RESULTS 
Thickness 3.0 to 3.3 mils (0.076 to 0.084 mm) 
______________________________________ 
Acetic Acid (10%) 
&gt;35 days &gt;35 days 
Methyl Ethyl Ketone 
&gt;35 days &lt;1 day 
Ethanol &gt;35 days &lt;1 day 
Methylene Chloride 
&gt;35 days &lt;1 day 
Acetone &gt;35 days &lt;1 day 
Refluxing (MEK) 
24 days &lt;5 minutes 
______________________________________ 
EXAMPLE 15 
______________________________________ 
PHYSICAL TEST RESULTS 
______________________________________ 
Formulation LL MM (control) 
Contains AA DFCA 
Gel @ 171.degree. C. 
49 sec. 86 sec. 
Cure Schedule 30 min @ 200 .degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 3 mils 3 mils 
(0.076 mm) (0.076 mm) 
Closed Direct Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Mandrel Bend Pass 1/8 inch Pass 1/8 inch 
(3.2 mm) (3.2 mm) 
______________________________________ 
______________________________________ 
CHEMICAL TEST RESULTS 
Thickness 12-16 mils (0.305 to 0.406 mm) 
______________________________________ 
Boiling H.sub.2 O &gt;90 days 16 days 
Refluxing H.sub.2 SO.sub.4 (10%) 
&gt;90 days 42 days 
Refluxing NaOH (pH = 13.5) 
&gt;14 days 5 days 
______________________________________ 
EXAMPLE 16 
______________________________________ 
PHYSICAL AND CHEMICAL TEST RESULTS 
______________________________________ 
Formulation GG HH (control) 
Contains AA DFCA 
Cure Schedule 30 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 2.0-2.2 mils 2.0-2.5 mils 
(0.0508-0.056 mm) 
(0.0508-0.0635 mm) 
Open Reverse Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Mandrel Bend Pass 1/8 inch 
Pass 1/8 inch 
(3.2 mm) (3.2 mm) 
Methyl Ethyl Ketone 
5 min. 5 min. 
Refluxing H.sub.2 SO.sub.4 (10%) 
76 hours 30 min. 
______________________________________ 
EXAMPLE 17 
______________________________________ 
PHYSICAL AND CHEMICAL TEST RESULTS 
______________________________________ 
Formulation II HH (control) 
Contains BB DFCA 
Cure Schedule 
30 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 3.0 mils 2.0-2.5 mils 
(0.076 mm) (0.0508 to 0.0635 mm) 
Open Reverse Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Mandrel Bend Pass 1/8 inch 
Pass 1/8 inch 
(3.2 mm) (3.2 mm) 
Methyl Ethyl Ketone 
6 hours 5 min. 
Refluxing H.sub.2 SO.sub.4 
174 hours 30 min. 
(10%) 
______________________________________ 
EXAMPLE 18 
______________________________________ 
PHYSICAL AND CHEMICAL TEST RESULTS 
______________________________________ 
Formulation JJ FF (control) 
Contains CC DFCA 
Cure Schedule 30 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 3.2-3.5 mils 3.0-3.2 mils 
(0.081-0.089 mm) 
(0.076-0.081 mm) 
Closed Direct Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Mandrel Bend Pass 1/8 inch Pass 1/8 inch 
(3.2 mm) (3.2 mm) 
Methyl Ethyl Ketone 
&gt;14 days &lt;5 min. 
______________________________________ 
EXAMPLE 19 
______________________________________ 
PHYSICAL AND CHEMICAL TEST RESULTS 
______________________________________ 
Formulation KK HH (control) 
Contains DD DFCA 
Cure Schedule 
30 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Appearance Smooth Smooth 
Thickness 2.2 mils 2.0-2.5 mils 
(0.056 mm) (0.0508-0.0635 mm) 
Closed Direct Impact 
&gt;160 inch-lbs. 
&gt;160 inch-lbs. 
(&gt;1.76 Kg m) (&gt;1.76 Kg m) 
Methyl Ethyl Ketone 
1 day 5 min. 
______________________________________ 
EXAMPLE 20 
In order to ascertain the influence of stoichiometry on curing epoxy resins 
with the hydroxyl terminated hardeners of this invention and with the 
objective of delineating the area where flexibility and chemical 
resistance of the cured products would be maximized, a series of runs are 
carried out using the hardener product AA prepared in Example 1 with the 
epoxy resin formulations similar to LL described in Example 12 with the 
equivalent ratio of epoxy groups of the epoxy resin to the phenolic 
hydroxyl groups of the hardener ranging from 1:0.4 to 1:1.2. The results 
of these runs are seen in the table below where the physical properties of 
the films prepared from the cured compositions are delineated. 
These results show that physical properties of the cured products reach a 
maximum in terms of impact strength (toughness) and flexibility when the 
ratio of equivalents of epoxy to hydroxyl is in the region of 1:0.5 to 
1:0.8 and particularly at about 1:0.65 to 1:0.75. 
__________________________________________________________________________ 
Equivalent Ratio 
Hydroxyl/Epoxy 
0.4/1.0 
0.5/1.0 
0.6/1.0 
0.7/1.0 
0.8/1.0 
0.9/1.0 
1.0/1.0 
1.1/1.0 
1.2/1.0 
__________________________________________________________________________ 
Thickness (mils.) 
2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 
(mm) 0.0508 
0.076 
0.076 
0.076 
0.076 
0.076 
0.076 
0.076 
0.076 
Impact (in.-lbs.) 
&gt;20 120-140 
140-160 
&gt;160 
60 &lt;20 &lt;20 &lt;20 &lt;20 
(Kg m) &lt;0.22 
1.32-1.54 
1.54-1.76 
&gt;1.76 
0.66 
&lt;0.22 
&lt;0.22 
&lt;0.22 
&lt;0.22 
Mandrel Bend 
Cracks 
Pass Pass Pass 
Cracks 
Cracks 
Cracks 
Cracks 
Cracks 
(1/8 inch) 
(3.2 mm) 
MEK (Immersion - 
&lt;7 hrs. 
NC* NC* NC* NC* NC* 19 hrs. 
&lt;7 hrs. 
&lt;7 hrs. 
Room Temperature) 
softens softens 
softens 
softens 
__________________________________________________________________________ 
*NC-- No change after 8 weeks exposure. 
EXAMPLE 21 
The effect of using an instant multifunctional hydroxy terminated curing 
agent, with relatively large distances between phenolic hydroxyl moieties, 
in contrast to a multifunctional hydroxy terminated curing agent of the 
prior art, with relatively short distances between phenolic hydroxyl 
moieties therein, on the physical properties, such as adhesion, 
flexibility and chemical resistance, of an epoxy resin formulation cured 
thereby is seen by inspection of the data given below. 
An epoxy resin formulation based on 
1,1,2,2-tetrakis-(p-glycidyloxyphenyl)ethane is cured using either the 
instant hardener of Example 1 (the product AA) or the prior art hardener 
having the structure 
##STR19## 
where n is 2 to 4, designated as hardener HT. 
The respective formulations are designated (A) and (B) as given below. Each 
formulation has one equivalent of epoxy to one equivalent of epoxy to one 
equivalent of phenolic hydroxyl. 
______________________________________ 
Formulation A 
Weight Grams 
______________________________________ 
1,1,2,2-tetrakis-(p-glycidyl- 
44.1 
oxyphenyl)ethane 
Product AA 88.2 
Flow Aid ("MODAFLOW") 
2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
______________________________________ 
Formulation B 
______________________________________ 
1,1,2,2-tetrakis-(p-glycidyl- 
87.75 
oxyphenyl)ethane 
Product HT 44.7 
Flow Aid ("MODAFLOW") 
2.25 
2-methylimidazole 0.3 
Red Iron Oxide 15.0 
______________________________________ 
These two formulations are then processed and applied as seen in Example 5 
and the resulting coated panels are tested for chemical resistance as seen 
in Example 14 and for physical characteristics as seen in Example 15. 
These test data are given in the following table. 
______________________________________ 
SOLVENT RESISTANCE AND PHYSICAL TEST RESULTS 
______________________________________ 
Formulation Formulation 
Sample Thickness 
SOLVENT A (Cured) B (Cured) mils mm 
______________________________________ 
MEK 40 days NC 40 days NC 2.0-2.5 
0.0508-0.0635 
(Room 
Temper- 
ature) 
Ethanol 40 days NC 40 days NC 2.0-2.5 
0.0508-0.0635 
Methylene 
40 days NC 40 days NC 2.0-2.5 
0.0508-0.0635 
Chloride 
10% Acetic 
40 days NC 40 days NC 2.0-2.5 
0.0508-0.0635 
Acid 
Acetone 40 days NC 14 days - few 
2.0-2.5 
0.0508-0.0635 
small blisters 
MEK 24 days - few 
120 days NC 
12-14 0.305-0.356 
(Refluxing) 
small blisters 
H.sub.2 O 
120 days NC 
-- 12-14 0.305-0.356 
(Boiling) 
______________________________________ 
TEST A B 
______________________________________ 
Gel @ 171.degree. C. time 
44 sec. 55 sec. 
Mandrel Bend Pass 1/2 inch &gt;1/2 inch 
(12.7 mm) (&gt;12.7 mm) 
Open Reverse Impact 
20 in.-lbs. 2 to 4 inch-lbs 
(0.22 Kg m) (0.022-0.044 Kg m) 
Thickness 2.0-2.5 mils 2.0-2.5 mils 
(0.0508-0.0635 mm) 
(0.0508-0.0635 mm) 
Cure Schedule 
20 min. @ 200.degree. C. 
30 min. @ 200.degree. C. 
Adhesion Excellent Fair-Good 
(% retention) 
(100%) (50-70%) 
______________________________________ 
NC = No change 
MEK = methyl ethyl ketone 
Inspection of the data given on the table shows that the prior art hardener 
(Formulation B) gives a cured epoxy resin product having appreciably less 
flexibility, impact resistance and adhesion than the instant hardener 
(Formulation A). Chemical or solvent resistance is comparable. 
These data show that the instant hardeners provide improved physical 
properties while maintaining good chemical resistance.