Production of thermosetting resinous polyepoxides

In one aspect, thermosetting liquid resinous polyepoxides are upgraded or advanced in molecular weight by a process including (A) providing a catalyst-free mixture of a dihydric phenol, preferably bisphenol-A and a liquid resinous polyepoxide containing 1,2-epoxy groups, preferably a low molecular weight epoxy resin consisting essentially of the diglycidyl ether of bisphenol-A, at a temperature above about a minimum reaction temperature for a catalytic liquid upgrade reaction between the dihydric phenol and the polyepoxide; and (B) subsequently introducing the catlyst, preferably an organic phosphine and most preferably triphenylphosphine, into the mixture of the dihydric phenol and polyepoxide at reaction temperature and maintaining the mixture containing the catalyst at reaction temperature for a time sufficient to produce the upgraded version of the thermosetting resinous polyepoxide. In another aspect, multiple catalyst additions are featured wherein, for example, after a first catalytic amount of a catalyst is introduced into the mixture of dihydric phenol and polyepoxide and the reaction has been maintained for a first period of time, a second catalytic amount of the catalyst is introduced into the mixture while at reaction temperature to upgrade further the polyepoxide. In yet another aspect of the disclosure, thermosetting resinous polyepoxides of improved molecular weight distribution are obtained by a process, preferably a continuous process, which involves (A) providing a catalyst-free mixture of bisphenol-A and a liquid resinous polyepoxide consisting essentially of an aromatic polyepoxide of the structural formula: ##STR1## to a temperature between 120.degree. C. and about 200.degree. C.; and (B) subsequently introducing triphenylphosphine into the mixture of the dihydric phenol and aromatic polyepoxide at a reaction temperature above 120.degree. C. and maintaining the mixture containing the catalyst at reaction temperature for a time between about 5 and about 30 minutes.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to improvements in the production of thermosetting 
resinous polyepoxides, including processes and products resulting 
therefrom. 
2. Summary of the Prior Art 
Since their discovery, thermosetting resinous polyepoxides, i.e., epoxy 
resins, have in industries and scientific disciplines found application in 
many forms, principally as surface-coating materials combining toughness, 
flexibility, adhesion and chemical resistance to a nearly unparalleled 
degree. 
The epoxy resins are fundamentally polyethers, but retain their epoxy 
nomenclature on the basis of their starting material and the presence of 
epoxide groups in the polymer before crosslinking or curing. The most 
common types of resinous polyepoxides are produced by reaction of 
monomeric epoxy compounds, chiefly epichlorohydrin, with dihydric phenols, 
chiefly bisphenol-A, to give diglycidyl ethers. 
Depending upon molecular weight, the resinous polyepoxide may vary from a 
viscous liquid to a high melting solid. The higher molecular weight 
resinous polyepoxides can be made by a process known as "upgrading" or 
"advancement". In such an upgrading or advancement process, an initial 
liquid resinous polyepoxide is reacted with a dihydric phenol in the 
presence of a catalyst until enough of the dihydric phenol is incorporated 
into the epoxy polymer chain to increase molecular weight to the desired 
level. 
Such upgrading processes have in the past been conducted both on a batch 
basis and on a continuous basis. See, for example, U.S. Pat. Nos. 
3,547,881 and 3,919,169. In such known batch and continuous upgrading 
processes, the dihydric phenols and liquid polyepoxide together with a 
catalyst are admixed or otherwise contacted at a relatively low 
temperature and then heated up to the reaction temperature and held at 
reaction temperature for a time sufficient to produce the resinous 
polyepoxide of higher molecular weight. 
In such known batch and continuous upgrading processes, however, cycle 
times are typically relatively lengthy. For example, batch reactions 
involving bisphenol-A and a liquid polyepoxide consisting essentially of 
the diglycidyl ether of bisphenol-A can take from about 10 to about 20 
hours for the reaction to be completed. The continuous process described 
in U.S. Pat. No. 3,919,169 involves a shorter time on the order of about 2 
hours, but in a continuous process it would be highly advantageous if the 
reaction time could be shortened significantly below this level. 
In addition to economies of time, such long cycle or reaction times can 
lead to a relatively wide molecular weight distribution which may in turn 
lead to end use disadvantages. For example, surface coating imperfections 
or "orange peel" has been observed when molecular weight distribution and 
concomitant viscosity characteristics are not properly controlled. 
SUMMARY OF THE INVENTION 
Accordingly, a primary object of the present invention is to provide 
improvements in the production of thermosetting resinous polyepoxides, 
which improvements significantly alleviate or do not incur the problems 
and disadvantages discussed above. Other and more particular objects of 
the present invention will become apparent to one skilled in the art from 
the following summary of the invention and description of the preferred 
embodiments: 
In accordance with one aspect of the present invention, a process is 
provided for upgrading or advancing the molecular weight of thermosetting 
resinous polyepoxides, which process involves: 
(A) providing a catalyst-free mixture of a dihydric phenol and a resinous 
polyepoxide containing 1,2-epoxy groups at a temperature above about a 
minimum reaction temperature for a catalytic liquid upgrade reaction 
between the dihydric phenol and the polyepoxide; and 
(B) subsequently introducing the catalyst into the mixture of the dihydric 
phenol and polyepoxide at reaction temperature and maintaining the mixture 
containing the catalyst at reaction temperature for a time sufficient to 
produce an upgraded thermosetting resinous polyepoxide. 
In accordance with another more particular aspect of the present invention, 
a process is provided for upgrading thermosetting liquid resinous 
polyepoxides, which process consists essentially of the sequential steps 
of: 
(A) heating under agitation a catalyst-free mixture of bisphenol-A and a 
liquid resinous polyepoxide consisting essentially of a polyepoxide of the 
structural formula: 
##STR2## 
PG,6 to a reaction temperature above 120.degree. C and for a time 
sufficient to obtain a substantially homogenous solution wherein the 
bisphenol-A is substantially completely dissolved; and 
(B) admixing the solution at a reaction temperature above 120.degree. C 
with a catalytic amount of triphenylphosphine and maintaining the 
admixture at reaction temperature for a time sufficient to produce an 
upgraded thermosetting resinous polyepoxide consisting essentially of a 
polyepoxide of the structural formula: 
##STR3## 
wherein n has an average value between about 4 and about 6. 
A central feature of the above-noted aspects of the present invention is 
the discovery that if a catalyst such as triphenylphosphine is withheld or 
not introduced into the reaction mixture of resinous polyepoxide and a 
dihydric phenol such as bisphenol-A until the reaction mixture has been 
raised to reaction temperature, the reaction will occur at a significantly 
greater rate and therefore may be completed to the desired extent in a 
significantly shorter reaction time than if the same amount of catalyst is 
preheated with the reactants. While not wishing to be bound by any theory 
underlying the present invention, it is presently believed that heretofore 
catalysts have been deactivated to a certain degree whenever they have 
been admixed with the reactants, either singularly or together, at a 
temperature lower than the minimum temperature needed for initiation of 
the reaction. This is indeed surprising for U.S. Pat. No. 3,919,169, for 
example, teaches that preheating of a mixture of the catalyst and the 
reactants below the reaction temperature is allegedly highly desirable. 
In another aspect of the present invention, such advancement or upgrade 
reactions are subjected to multiple catalyst addition. For example, after 
a first catalytic amount of the catalyst is introduced into the mixture of 
the dihydric phenol and the liquid resinous aromatic polyepoxide and the 
reaction has been maintained for a first period of time, a second 
catalytic amount of the catalyst is introduced into the mixture while at 
reaction temperature to upgrade further the polyepoxide. Similarly, third, 
fourth and yet additional catalyst additions may be made. Such multiple 
catalyst additions have been found to increase not only the rate of 
reaction, but also the extent of reaction between the dihydric phenol and 
the initial or starting resinous polyepoxide. 
In yet another aspect of the present invention, a process is provided for 
upgrading thermosetting liquid resinous polyepoxides, the process 
including: 
(A) providing a catalyst-free mixture of bisphenol-A and a liquid resinous 
polyepoxide consisting essentially of a polyepoxide of the structural 
formula: 
##STR4## 
at a reaction temperature above about 160.degree. C, and 
(B) thereafter admixing triphenylphosphine with the mixture of bisphenol-A 
and the polyepoxide and maintaining the mixture containing the catalyst at 
reaction temperature above 160.degree. C for a time between about 5 and 30 
minutes and sufficient to produce an upgraded thermosetting resinous 
polyepoxide consisting essentially of an aromatic polyepoxide of the 
structural formula: 
##STR5## 
wherein n has an average value between about 4 and about 6, and wherein 
the resinous polyepoxide has a weight per epoxide value of between about 
600 and about 1000 and a molecular weight distribution value between about 
1.6 and about 1.9. 
In yet another aspect of the present invention, a continuous process is 
provided for upgrading thermosetting liquid resinous polyepoxides, which 
process consists essentially of: 
(A) passing catalyst-free bisphenol-A through a first zone to heat the 
bisphenol-A to a temperature between about 160.degree. C and 180.degree. 
C, the bisphenol-A being in a molten state upon emerging from the first 
zone; 
(B) passing catalyst-free liquid resinous polyepoxide consisting 
essentially of a polyepoxide of the structural formula: 
##STR6## 
through a second zone to heat the liquid resinous polyepoxide to a 
temperature between 120.degree. C and about 180.degree. C; 
(C) in a third zone downstream of the first and second zones, admixing the 
bisphenol-A and the liquid resinous polyepoxide to provide a catalyst-free 
mixture of bisphenol-A and the polyepoxide at a temperature between 
120.degree. C and about 200.degree. C 
(D) in a fourth zone downstream of the third zone, admixing the solution at 
a reaction temperature between about 120.degree. C and 200.degree. C with 
a catalytic amount of triphenylphosphine and maintaining the admixture at 
a reaction temperature between 120.degree. C and about 250.degree. C, 
preferably between about 160.degree. C and 240.degree. C, for a time 
between about 5 and about 30 minutes and sufficient to produce an upgraded 
thermosetting resinous polyepoxide consisting essentially of a polyepoxide 
of the structural formula 
##STR7## 
wherein n has an average value between about 4 and about 6, and wherein 
the upgraded resinous polyepoxide has a weight per epoxide value of from 
about 600 to about 1000 and a molecular weight distribution value between 
about 1.6 and about 1.9. 
In the last two of the above-noted aspects of the present invention, a 
central feature is that the increased rate of reaction and concomitant 
relatively short reaction or cycle time leads to the production of a 
resinous polyepoxide of a relatively narrow molecular weight distribution. 
This molecular weight distribution in turn may provide enhanced utility 
for many applications. For example, the improved molecular weight 
distribution typically leads to better flow characteristics and 
elimination of any "orange peel" effects in the coating surface. 
Other aspects and advantages of the present invention will become apparent 
to one skilled in the art in view of the above and the following 
description of the preferred embodiments when read in conjunction with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As indicated above, a dihydric phenol is reacted with a thermosetting 
resinous polyepoxide to produce the upgraded or advanced resinous 
polyepoxide of higher molecular weight than the initial resinous 
polyepoxide. 
In general, any dihydric phenol may be used. For example, suitable dihydric 
phenols may be represented by the structural formulas 
##STR8## 
wherein R.sub.1 may independently be selected from the group consisting of 
hydrogen, lower alkyl, chlorine and bromine, and wherein R.sub.2 may be 
selected from the group consisting of a divalent bond, a divalent 
hydrocarbon radical of from 1 to 10 carbon atoms, 
##STR9## 
--S--, --S--S-- and --O--. 
Non-limiting examples of such dihydric phenols include bisphenol-A, 
bisphenol-ACP, bisphenol-L, bisphenol-V, dichlorobisphenol-A, 
tetrachlorobisphenol-A, tetrabromobisphenol-A, resorcinol, hydroquinone, 
2,2-bis(4-hydroxyphenyl) pentane, 2,2-bis(4-hydroxyphenyl) pentanoic acid, 
2,2-bis(4-hydroxyphenyl)sulfone, 2,2-bis(4-hydroxyphenyl)methane, 
bis(3-allyl-4-hydroxyphenyl)propane, 
2,2-bis(3-isobutyl-4-hydroxyphenyl)pentane, as well as 
##STR10## 
Bisphenol-A is the most preferred dihydric phenol because of its ready 
reactivity, polyaromatic nucleus structure, and its wide availability. 
In general, any thermosetting resinous polyepoxide containing at least two 
1,2-epoxy groups may be upgraded or advanced in molecular weight by 
reaction with at least one of the above-noted dihydric phenols. Such 
resinous polyepoxides may be of the structural formula 
##STR11## 
wherein R.sub.3 is a divalent aliphatic, cycloaliphatic, heterocyclic or 
aromatic radical. Generally, such resinous polyepoxides are characterized 
by weight per epoxide equivalent values which may range up to about 2,000, 
and more typically is between about 100 and about 1,000. 
Non-limiting examples of such resinous polyepoxides may be found in "New 
Linear Polymers", Lee, Stoffey and Neville (1967 McGraw-Hill); "Handbook 
of Epoxy Resins", Lee and Neville (McGraw-Hill 1967); and U.S. Pat. Nos. 
2,615,007; 2,615,008; 3,325,452; 3,334,068 and 3,352,825, all of which are 
incorporated herein by reference for purposes of brevity and clarity. 
More preferably, the starting thermosetting resinous polyepoxides consist 
essentially of polyepoxides of the structural formula 
##STR12## 
wherein R.sub.1 and R.sub.2 may independently be selected from their 
respective groups given earlier above and where n varies between zero and 
a small number less than about 10. When R.sub.1 is H, R.sub.2 is 
##STR13## 
and n is essentially zero, the resin is a very fluid light colored 
material which is essentially the diglycidyl ether of bisphenol-A. 
As indicated above, these polyepoxides may also be characterized by weight 
per epoxide equivalent values. Weight per epoxide equivalent or "WPE" is 
defined and used herein to indicate the grams of resinous polyepoxide 
containing one gram equivalent of epoxy groups. Weight per epoxide 
equivalent is determined hereby by the procedures described in "Epoxy 
Resins", pp. 133-135, Burge, Jr. and Geyer, Analytical Chemistry of 
Polymers, Part I, Kline, Ed. (Interscience 1959), except that potassium 
acid phthalate was employed to standardize the acid solution, and except 
that chlorobenzene/chloroform 8/5, V/V, was used as the resin solvent 
(this procedure is incorporated hereby by reference for purposes of 
brevity). 
As the molecular weight and weight per epoxide equivalent value increase so 
generally does the viscosity of these resinous polyepoxides. Accordingly, 
particularly preferred liquid resinous polyepoxides generally possess an n 
value averaging less than about 1, i.e., a liquid resinous polyepoxide 
consisting essentially of the diglycidyl ether of bisphenol-A having the 
structural formula 
##STR14## 
Such a polyepoxide may have a weight per epoxide equivalent value between 
about 180 and about 240. The term "liquid" means that the initial 
polyepoxide is in the liquid state at ambient conditions, i.e., 25.degree. 
C and 760 mmHg. 
The catalyst may be any compound or mixture of compounds which will 
catalyze the reaction between the hydroxy group of the bisphenol-A and the 
epoxy group of the initial polyepoxide. Such catalysts may be organic or 
inorganic, or a combination of both. Non-limiting examples of organic 
catalysts include the organic phosphines of the formula 
##STR15## 
wherein R.sub.4 is an organic radical and R.sub.5 and R.sub.6 are 
independently selected from hydrogen and organic radicals. Such organic 
radicals may be hydrocarbon or substituted hydrocarbon radicals of from 
one to about twenty carbon atoms. Non-limiting examples of such phosphines 
include triphenylphosphine, tri-p-tolylphosphine, 
tris-p-chlorophenylphosphine, tri-n-butylphosphine, dibutylallylphosphine, 
trilaurylphosphine, trihexenylphosphine, tridodecylphosphine, 
dicyclohexylphosphine, trinaphthylphosphine, triethoxybutylphosphine, 
tris-p-methoxyphenylphosphine, tris-p-fluorophenylphosphine, and 
##STR16## 
Other catalysts include tertiary amines, e.g., trioctylamine and 
tributylamine; organic ammonium compounds such as benzyl trimethylammonium 
chloride; organic phosphonium compounds such as ethyltriphenyl phosphonium 
iodide and ethyltriphenyl phosphonium acetate acid complex. Inorganic 
catalysts include alkali metal hydroxides, e.g., potassium hydroxide and 
ether complexes thereof, alkali metal iodides, e.g., potassium iodide. 
Mixed catalyst systems may also be used. Others will be evident to one 
skilled in the art from the disclosure herein. 
The catalyst may be present in the reaction mixture in any suitable 
catalytic amount as will be evident to one skilled in the art from the 
present specification. For example, catalyst may be present in an amount 
of from 0.001 to 10%, more typically from about 0.01 to 5%, and preferably 
from about 0.05 to 1%, based on the weight of dihydric phenol and 
polyepoxide reactants. 
The amount of dihydric phenol and initial resinous polyepoxide to be 
employed in the process may vary over a wide range depending upon the type 
of reactants and the type of product to be desired. For example, the 
dihydric phenol and the polyepoxide reactants may be used in equivalency 
ratios of phenolic (Ar--OH) to epoxide groups 
##STR17## 
of from about 0.1:1 up to 1:1, more typically from about 0.2 to 0.95:1, 
and preferably from about 0.5 to 0.90:1. 
As indicated above in the summary of the present invention, the dihydric 
phenol and the initial resinous polyepoxide are heated separately or 
together and provided as a catalyst-free mixture at a temperature above 
about a minimum or initial reaction temperature for a catalytic liquid 
upgrade reaction between the dihydric phenol and the polyepoxide. 
More particularly, the dihydric phenol and the resinous polyepoxide may be 
separately heated to the minimum reaction temperature and then contacted 
or admixed together to form the catalyst-free mixture at a temperature 
above the minimum reaction temperature, or the dihydric phenol and 
resinous polyepoxide may be admixed at a lower temperature, and the 
catalyst-free admixture heated to a temperature of above about that of the 
minimum reaction temperature. 
The minimum or initial reaction temperature is defined herein as that 
minimum or initial temperature at which in the presence of a catalyst the 
dihydric phenol and initial resinous polyepoxide begin to react 
exothermally. Once the exothermic reaction is initiated, in the absence of 
cooling the reaction mixture will rise in temperature. Minimum or initial 
reaction temperatures for various systems of specific dihydric phenols, 
resinous polyepoxides and catalysts are known to those skilled in this 
art. If the minimum or initiating reaction temperature is not known for a 
particular system of dihydric phenol, resinous polyepoxide and catalyst, 
then the minimum or initiating reaction temperature may be conveniently 
determined by mixing small amounts of the dihydric phenol and polyepoxide 
together with the catalyst and then heating the mixture slowly until the 
initial reaction exotherm is detected. 
It may be noted at this point that the term "catalyst-free mixture" means a 
mixture of dihydric phenol and resinous polyepoxide which contains no 
appreciable amounts of catalyst such that the reaction would, in the 
absence of additional catalyst, begin to react exothermically at a 
temperature of above about that of the minimum reaction temperature. 
Once the catalyst-free mixture of dihydric phenol and resinous polyepoxide 
has been provided at the temperature of above about that of the minimum 
reaction temperature, the catalyst may then be introduced into the mixture 
of the dihydric phenol and polyepoxide. If desired, such introduction of 
the catalyst may be substantially instantaneous with the mixing of the 
dihydric phenol and the polyepoxide. As indicated above, however, if the 
catalyst is added to the dihydric phenol and polyepoxide prior to heating 
to reaction temperature, at least some of the catalyst will be deactivated 
and the rate and perhaps extent of reaction will be adversely affected. 
Once the catalyst has been introduced or admixed into the reactant mixture 
of dihydric phenol and polyepoxide, the admixture containing the catalyst 
is then maintained at reaction temperature for a time sufficient to 
produce an upgraded resinous polyepoxide of the desired molecular weight. 
This maintenance or holding time for the reactant mixture will vary 
depending upon the dihydric phenol, polyepoxide and catalyst used, as well 
as the level of reaction temperature chosen. 
Conveniently, upon addition of the catalyst the reaction mixture is allowed 
to exothermally rise in temperature, and after such an exothermic rise the 
temperature need only be maintained above the minimum or initial reaction 
temperature. 
For example, in the case of bisphenol-A and an initial liquid resinous 
polyepoxide consisting essentially of the diglycidyl ether of bisphenol-A 
and triphenylphosphine as a catalyst, minimum or initial reaction 
temperature is slightly above 120.degree. C, e.g., 125.degree.-130.degree. 
C. Once this reaction is initiated, the temperature of the reaction 
mixture will typically rise over a period of about one to ten minutes to a 
maximum range of about 220.degree. to 250.degree. C, and then the reaction 
temperature may be allowed to fall somewhat, e.g., to between about 
150.degree. C and about 220.degree. C for the remainder of the reaction 
period. 
The reaction may be maintained, i.e., the polyepoxide may be allowed to 
increase in molecular weight and weight per epoxide equivalent, for a 
period of time sufficient to produce the thermosetting polyepoxide 
upgraded or advanced to the desired molecular weight and weight per 
epoxide equivalent. For example, when the final product has the structural 
formula 
##STR18## 
where R.sub.1 and R.sub.2 have the meaning given above, the average value 
of n may be allowed to increase by at least about 2, and preferably by 
about 4 to 6, from its initial value. 
The reaction may be carried out in any convenient stirred or non-stirred 
reactor. Preferably, the reaction is conducted under agitation for at 
least part of the total reaction time to ensure a substantially 
homogeneous reaction mixture or solution. 
As indicated above, another aspect of the present invention involves 
multiple catalyst addition. In other words, after a first catalytic amount 
of the catalyst is introduced into the mixture of dihydric phenol and the 
polyepoxide and the reaction has been maintained for a first period of 
time, further catalytic amounts of the catalyst may be introduced into the 
mixture while at reaction temperature to upgrade further the polyepoxide. 
Such additional increments of catalyst introduced during the reaction have 
been found unexpectedly to both increase the rate of reaction as well as 
the extent of reaction. Ratios of such catalyst increments may vary over a 
wide range, e.g., between about 1:10 to 10:1, more typically between about 
2:1 to about 1:2. 
As indicated above, it may be desired to control or affect molecular weight 
distribution in the resulting epoxy resin product. For the preferred 
starting reactants, bisphenol-A and polyepoxide consisting essentially of 
diglycidyl ether of bisphenol-A, this process typically involves 
(A) providing a catalyst-free mixture of bisphenol-A and a liquid resinous 
polyepoxide consisting essentially of a polyepoxide of the structural 
formula: 
##STR19## 
at a reaction temperature above about 160.degree. C, typically less than 
about 250.degree. C, preferably between 160.degree. and 180.degree. C; and 
(B) thereafter admixing triphenylphosphine with the mixture of bisphenol-A 
and the polyepoxide and maintaining the mixture containing the catalyst at 
a reaction temperature above 160.degree. C for a time between about 5 and 
30 minutes and sufficient to produce an upgraded thermosetting resinous 
polyepoxide consisting essentially of an aromatic polyepoxide of the 
structural formula 
##STR20## 
wherein n has an average value between about 2 and about 8, more typically 
between about 4 and about 6, and wherein the resinous polyepoxide has a 
weight per epoxide value of between about 500 and 2000, more typically 
between 700 and about 1000, and a molecular weight distribution value 
between about 1.6 and about 1.9. 
This particular process takes advantage of the discovery of the increased 
rate of reaction and controls or improves molecular weight distribution 
(MWD) and concomitant viscosity in the resulting thermosetting polyepoxide 
product. More particularly, since molecular weight distribution increases 
with increasing time in the reaction mixture, the increased rate of 
reaction (i.e., increased rate of increase of weight per epoxide 
equivalent) allows a significantly shorter overall reaction time to 
produce a polyepoxide of the desired final weight per epoxide equivalent 
and final MWD value or viscosity value. This can lead to improved coating 
and curing characteristics, including elimination or at least significant 
alleviation of "orange peel" effects. 
Molecular weight distribution or "MWD" values are defined herein as the 
ratio of weight averaged molecular weight to number averaged molecular 
weight. (These molecular weight values may be determined from 
corresponding polystyrene Angstrom equivalents obtained by known gel 
permeation chromotography techniques.) 
The reaction between the dihydric phenol and the initial resinous 
polyepoxide is typically conducted in a melt or molten solution in the 
absence of an added solvent or diluent. If desired, however, a diluent or 
solvent may be added. Preferably, any such diluent or solvent has a normal 
boiling point greater than 110.degree. C. Examples of such solvents or 
diluents include inert organic liquids such as ketones, e.g., 
4-methyl-2-pentanone; aromatic hydrocarbons, e.g., xylenes; aliphatic 
hydrocarbons, e.g., octane; cycloaliphatic hydrocarbons, e.g., decalin; 
ethers, e.g., diphenyl ether and 1,2-bis(2-methoxyethoxy)ethane. 
The processes of the present invention may be conducted on a batch, 
semi-continuous or continuous basis. 
If conducted on a continuous basis, the process of the present invention 
preferably involves (referring to FIG. 1) passing the catalyst-free 
bisphenol-A from an inlet feed line 2 through a first zone 4 to heat the 
bisphenol-A to a temperature between about 160.degree. and 180.degree. C, 
the bisphenol-A being in a molten or liquid state upon emerging from the 
first zone 4. The first zone may comprise a heated axial feeder 6 
connected to a line 8 and a heated holding tank 10. Heated fluid may be 
supplied through a line 12 to heat or maintain the bisphenol-A at the 
desired temperature by means of a conventional heat exchanger 
relationship. Nitrogen or other inert gas may be supplied through a line 
14 to the interior of the tank 10 so as to maintain an inert atmosphere 
about the molten bisphenol-A. 
Catalyst-free liquid resinous polyepoxide consisting essentially of a 
polyepoxide of the structural formula 
##STR21## 
from inlet feed line 16 may be passed through a second zone 18 to heat the 
liquid resinous polyepoxide to a temperature between 120.degree. C and 
about 200.degree. C, preferably between about 160.degree. and 180.degree. 
C. The second zone 18 may comprise a heat exchanger 20 heated by a fluid 
circulating through lines 22 and 24. 
In a third zone 26 downstream of the first and second zones, bisphenol-A 
from the first zone 4 via line 30 and the liquid resinous polyepoxide from 
the second zone 18 via line 28 are contacted or admixed to provide a 
catalyst-free mixture of bisphenol-A and the polyepoxide at a temperature 
between 120.degree. and 200.degree. C, preferably between about 
160.degree. and 180.degree. C. 
In a fourth zone 32 downstream of the third zone 26, the mixture or 
solution of bisphenol-A and polyepoxide is contacted or admixed at a 
reaction temperature between 120.degree. and 200.degree. C, preferably 
between about 160.degree. and 180.degree. C with a catalytic amount of 
triphenylphosphine. The triphenylphosphine may be provided via an inlet 
line 34 to an agitated tank 36 which may be heated by means of a steam 
line 38 to a temperature of between about 85.degree. and 150.degree. C. 
Nitrogen or other inert gas may be supplied to tank 36 via line 39 to 
maintain a blanket about the heated catalyst. From tank 36 the catalyst 
may be fed via line 40 to the initial contacting or mixing zone 32. In 
zone 32 a tubular reactor 42 equipped with in-line mixers or agitators 44 
may ve provided to maintain the reaction mixture of bisphenol-A, 
polyepoxide and catalyst under agitation at a reaction temperature between 
120.degree. C and about 250.degree. C, preferably between about 
160.degree. and 240.degree. C, for a time between about 5 minutes and 
about 30 minutes, and sufficient to produce an upgraded thermosetting 
resinous polyepoxide product consisting essentially of a polyepoxide of 
the structural formula 
##STR22## 
wherein n has an average value between about 4 and about 6, and wherein 
the upgraded resinous polyepoxide has a weight per epoxide value of from 
about 600 to about 1000 and a molecular weight distribution value between 
about 1.6 and about 1.9. A conventional heating fluid may be provided via 
a line 46 and about the tubular reactor 42 to maintain the desired 
reaction temperature. From tubular reactor 42, the upgraded polyepoxide 
product may be recovered via a line 48, a vacuum evaporator 50, and then 
to a conventional water-chilled belt-cooler 52 for solidification and to a 
grinder 54 for subdividing the solid product into chips or granules of a 
desired size. From the grinder 54 the polyepoxide product may be passed to 
a packaging zone 56. 
The products of the present invention are terminated in 1,2-epoxy groups 
and are thus thermosetting, and can be cured with a wide variety of curing 
systems as known to those skilled in the art. The reactive epoxide and 
also hydroxyl groups are the points of reaction with curing agents and 
modifying resins. Numerous organic nitrogen compounds have been 
investigated for use as epoxy resin curing agents, and the amines, both 
aliphatic and aromatic, are the most useful. See, for example, "Polymers 
and Resins", Golding, pages 355-360 (Van Nostrand 1959); "Textbook of 
Polymer Science", Billmeyer, Jr., pages 478-480 (2nd Ed., 
Wiley-Interscience 1962), and "Handbook of Epoxy Resins", Lee and Neville 
(McGraw-Hill 1967), all of which are herein incorporated by reference for 
purposes of brevity and clarity of the present invention. 
The polyepoxides produced according to the present invention are useful in 
many applications, principally as surface-coating materials which 
typically exhibit toughness, flexibility, adhesion and chemical 
resistance. 
The present invention is further illustrated by the following specific 
examples. All parts ratios and percentages in the examples and in other 
parts of the specification and claims are by weight unless otherwise 
indicated. 
EXAMPLE I 
33.4 parts molten bisphenol-A were combined with 75.8 parts of a liquid 
resinous polyepoxide consisting essentially of the diglycidyl ether of 
bisphenol-A (Epi-Rez 510) having a WPE of 190 and mixed thoroughly while 
the melt temperature was adjusted to 172.degree. C as the initial reaction 
initiation temperature. Then 0.1 part triphenylphosphine was added with 
continued stirring. An immediate exotherm occurred which reached its peak 
value of 244.degree. C in 1.8 min. Stirring was continued an additional 25 
min. when the temperature had smoothly decreased to 207.degree. C. The 
resulting upgraded polyepoxide resin had the properties shown in Table I 
below. 
EXAMPLE II 
Example I was repeated except the initial reaction initiation temperature 
was 130.degree. C. A peak exotherm of 190.degree. C was observed in 10 
min. and the total reaction time was 62 min. Properties of the resulting 
resin are shown in Table I below. Samples were periodically withdrawn 
throughout the run. 
EXAMPLE III 
Example I was repeated except that a second 0.1 part triphenylphosphine was 
added to the reaction 4 minutes after the first addition. The initial peak 
exotherm of 244.degree. C was observed after 1.9 minutes. A second mild 
exotherm of from 227 to 231.degree. C was observed immediately after 
second addition of catalyst. Reaction was stirred 13 minutes after second 
catalyst addition. Properties of the resulting resin are shown in Table I 
below. Samples were periodically withdrawn throughout the run, WPE values 
determined, and plotted as shown in FIG. 2. 
COMATIVE RUN A 
33.4 parts bisphenol-A, 75.8 parts of a liquid resinous polyepoxide 
consisting essentially of the diglycidyl ether of bisphenol-A (Epi-Rez 
510) and 0.1 part triphenylphosphine were charged at room temperature 
(about 25.degree. C). With stirring and heating, the temperature was 
raised to 140.degree. C where a clear solution was obtained in sixteen 
minutes. An exotherm began which reached its peak value of 212.degree. C 
in an additional 5 minutes. Stirring was continued an additional 27 
minutes during which the temperature smoothly decreased to 192.degree. C. 
The resulting resin had the properties shown in Table I below. Samples 
were periodically withdrawn throughout the run, WPE values determined, and 
plotted as shown in FIG. 2. 
COMATIVE RUN B 
All times based on phosphine addition as zero time. 33.4 parts bisphenol-A 
and 75.8 parts of a liquid resinous polyepoxide consisting essentially of 
the diglycidyl ether of bisphenol-A (Epi-Rez 510) were combined at room 
temperature and heated and stirred until a clear melt was obtained with a 
temperature of 111.degree. C. Then 0.1 part triphenylphosphine was charged 
and gentle heating begun such that after 6 minutes the temperature was 
115.degree. C. Heating was continued such that the temperature was 
135.degree. C after 14 minutes. After 19 minutes, temperature 162.degree. 
C, and exotherm was easily detected which maximized at 184.degree. C after 
22 minutes. The temperature was 159.degree. .+-. 3.degree. C from 52 to 68 
min. at which point external heating slowly began to raise the temperature 
such that it was 174.degree. C after 93 minutes and 186.degree. C at 120 
minutes. Properties of the resulting resin were WPE 1040; MWD 2.1; An 
87.7; Aw 189; melt viscosity at 150.degree. C, 115 poise. Samples were 
periodically withdrawn throughout the run. 
COMATIVE RUN C 
Example I was repeated except that the triphenyl phosphine was added to the 
solid bisphenol-A and then the mixture melted over the time of 5 hours (T 
= 160.degree. C) before combination with the liquid resinous polyepoxide 
consisting essentially of the diglycidyl ether of bisphenol-A (Epi-Rez 
510). Initial temperature of mixed reactants was 165.degree. C. A peak 
exotherm of 218.degree. C was reached 3.3 min. after addition. The 
addition was stirred for 21 minutes after peak exotherm during which time 
the temperature decreased to 198.degree. C. Properties are shown in Table 
I below. Samples were periodically withdrawn throughout the run. 
TABLE I 
__________________________________________________________________________ 
Example/Comp. Run 
I II III A B C 
__________________________________________________________________________ 
Initiation Temp. (.degree. C) 
172 130 172 156 160 165 
Total Run Time (Min.) 
27 62 17 32 126 31 
Peak Exotherm 
243 190 244 212 184 225 
Target WPD 1025 1025 1025 1025 1025 1025 
Final WPE 880 1017 892 774 1040 783 
Aw 123 155 128 121 189 106 
An 73.9 81.6 74.6 71.8 87.7 65.6 
MWD (Aw/An) 1.7 1.9 1.7 1.7 2.1 1.6 
Viscosity (poise at 150.degree. C) 
34 63 n.a. 26 115 24 
__________________________________________________________________________ 
EXAMPLE IV 
A continuous apparatus line, similar in design to the schematic shown in 
FIG. 1, was used to conduct continuous runs IV-a through IV-g. In Example 
IV-a, a diglycidyl ether of bisphenol-A (Epi-Rez 510) with an epoxide 
equivalent weight of 192 was fed continuously at an instantaneous rate of 
13.0 gms./min., and combined with a continuous stream of molten 
bisphenol-A metered at 5.8 gms./min. The temperature of the combined 
streams was 159.degree. C. Molten triphenylphoshine catalyst, at 
112.degree. C, was then added to the reactant material stream at a 
continuous rate of 0.0176 gms./min. Immediately following the catalyst 
addition the fluid mixture entered a two section continuous tubular 
reactor with in-line agitators or mixers. The first section consisted of a 
1/4 inch O.D., oil jacketed, Kenics Static Mixer.sup.(R) Module maintained 
at 164.degree. C. The second section consisted of a 9.5 ft. section of 3/8 
inch O.D. mixer modules connected in series and maintained at about 
160.degree. C. In the second section the materials reacted attaining a 
peak temperature of 241.degree. C. The temperature declined to 
174.degree. C at the end of the reactor where the molten polymer was 
quenched to the solid state on a chilled metal collector surface. The 
nominal mean residence time for this run was 9 minutes. Similar procedure 
was used for runs IV-b to IV-g. Other data and results for runs IV-a to 
IV-g on the continuous unit are shown in Table II below. 
TABLE II 
__________________________________________________________________________ 
Example IV a b c d e f g 
__________________________________________________________________________ 
Polyepoxide.sup.(1) (gms./min.) 
13.0 13.1 13.2 13.6 13.1 13.1 13.0 
Bisphenol-A (gms./min.) 
5.82 5.25 5.59 5.59 5.95 5.82 5.95 
Triphenylphosphine (gms./min.) 
0.0176 
0.0141 
0.0169 
0.0253 
0.0178 
0.0350 
0.0178 
Initiation Temperature (.degree. C) 
159. 162. 161. 160. 160. 158. 162. 
Peak Exotherm Temperature (.degree. C) 
241. 237. 236. 241. 228. 230. 227. 
Target WPE (gm./gm. equiv.) 
1125. 
895. 950. 878. 1133. 
1097. 
1216. 
Actual WPE (gm./gm. equiv.) 
858. 663. 824. 786. 863. 985. 934. 
Viscosity 47. 9.4 -- 31. 33. 71. 36. 
An 72.5 56.0 68.9 67.4 66.4 82.2 68.0 
Aw 131. 88.8 118. 119. 109. 154. 131. 
MWD 1.8 1.6 1.7 1.8 1.6 1.9 1.9 
Mean Residence Time (minutes) 
8.9 9.1 8.9 8.7 8.7 8.7 8.7 
__________________________________________________________________________ 
.sup.(1) Epi-Rez 510 A liquid diglycidyl ether of bisphenol-A having an 
epoxide equivalent weight of 185-200. 
As may be seen from the above, utilization of the present invention rapidly 
provides well-reacted products of relatively low viscosity. This low 
viscosity is a consequence of the relatively narrow molecular weight 
distribution, e.g., 1.6 - 1.9, which may be achieved by the present 
invention. The magnitude of this viscosity improvement is readily seen by 
comparing Example II with Comparative Run B. The two vary only 2% in WPE 
values but the resin of Comparative Run B has 1.8 times the melt viscosity 
of the resin of Example II. 
Of particular value and novelty is the rapid reaction rate of the present 
invention which can be readily seen in FIG. 2 which shows the WPE values 
versus time curves for Examples I and III and Comparative Run A. 
As shown by Example IV, this rapid rate makes the present invention well 
suited to continuous reaction giving a far shorter residence time than 
that taught by prior art. 
Comparative Run C demonstrates the deactivating effect upon the phosphine 
catalyst of contacting it with bisphenol alone and then adding the 
polyepoxide. Bisphenol-A causes in this run a partial loss of activity. 
Epoxides will cause a total loss of activity if similarly contacted alone 
with the catalyst with subsequent addition of bisphenol-A. Indeed, in a 
test of triphenylphosphine mixed with a liquid diglycidyl ether of 
bisphenol-A at 30 minutes at 150.degree. C, and in the absence of any 
added bisphenol-A, all catalytic activity was lost. 
While triphenylphosphine is a preferred catalyst, as may be seen in the 
following examples, other catalysts well known to the art can be employed. 
EXAMPLES V - VI 
Example II was repeated except that equimolar amounts of the catalysts 
shown in Table III below were employed. Exotherms, times, and properties 
are shown in Table III. 
TABLE III 
______________________________________ 
Example II V VI VII 
______________________________________ 
Catalyst.sup.a TPP TBP TOA KOH 
Parts by Weight .1 .08 .27 .03 
Peak Exotherm (.degree. C) 
190 195 171 198 
Target WPE 1025 1025 1025 1025 
Total Time (min) 
62 22 50 110 
Gross Initial Rate.sup.b 
55 39 21 9 
WPE 1017 1039 1041 1125.sup.c 
Aw 155 162 158 --.sup.c 
An 81.6 83.5 82.7 --.sup.c 
MWD 1.9 1.9 1.9 --.sup.c 
______________________________________ 
.sup.a TPP = triphenylphosphine; TBP = tributylphosphine; TOA = 
trioctylamine; KOH = potassium hydroxide. 
.sup.b Value of least squares straight line slope with correlation 
coefficient &gt;.95 for WPE vs time. 
.sup.c Catalyst incompletely solubilized. A constant WPE value was not 
achieved at the end of 110 minutes. 
The principles, referred embodiments and modes of operation of the present 
invention have been described in the foregoing specification. The 
invention which is intended to be protected herein, however, is not to be 
construed as limited to the particular forms disclosed, since these are to 
be regarded as illustrative rather than restrictive. Variations and 
changes may be made by those skilled in the art without departing from the 
spirit of the present invention.