Process for the preparation of cationic resins, aqueous, dispersions, thereof, and electrodeposition using the aqueous dispersions

An improved process for the preparation of cationic resins derived from polyepoxides is disclosed. Typically, the process comprises contacting the polyepoxide with particular polyether polyols and heating the two together to form a resin which may then be reacted with a cationic base group former such as an amine and acid. Aqueous dispersions of the cationic resins prepared by the improved process are useful for coating applications, particularly cationic electrodeposition. They exhibit good low temperature cure response and the cured coatings have good physical properties such as resistance to water, detergent and salt spray corrosion.

BACKGROUND OF THE INVENTION 
Field of the Invention: The present invention relates to a process for 
preparing cationic resins, to aqueous dispersions of the cationic resins, 
and to the use of these dispersions in cationic electrodeposition. 
Brief Description of the Prior Art: Cationic electrodeposition resins are 
well known in the art. For example, U.S. Pat. No. 4,104,147 to Jerabek et 
al discloses cationic electrodepositable resins which are formed from 
reacting a polyepoxide with a primary or secondary amine and solubilizing 
the polyepoxide-amine adduct in aqueous medium with the aid of acid. The 
polyepoxide is contacted and heated with a polymeric polyol, for example, 
a polyester polyol such as a polycaprolactone diol or a polyether polyol 
such as polyoxytetramethylene glycol before reaction with the primary or 
secondary amine. 
U.S. Pat. No. 3,839,252 discloses quaternary ammonium salt group-containing 
resins which are formed from reacting a polyepoxide with a tertiary amine 
salt. The polyepoxides are optionally contacted and heated with a 
polyether polyol such as polyoxypropylene glycol or polyoxyethylene glycol 
before reaction with the tertiary amine salt. 
U.S. Pat. No. 4,260,720 discloses cationic electrodepositable resins which 
are derived from a polymercapto-chain extended polyepoxide. Among the 
polyepoxides which may be used are polyglycidyl ethers of cyclic polyols 
such as bisphenol A and 1,2-bis(hydroxymethyl)cyclohexane. These 
polyepoxides can be produced by etherification of the cyclic polyol with 
epichlorohydrin in the presence of alkali. Besides bisphenol A and 
1,2-bis(hydroxymethyl)cyclohexane, oxyalkylated adducts of these cyclic 
polyols such as ethylene oxide and propylene oxide adducts can be used. 
SUMMARY OF THE INVENTION 
The present invention relates to an improved process for preparing a resin 
which contains cationic base groups comprising reacting a polyepoxide 
resin with a cationic base group former. The improvement of the invention 
comprises contacting a polyepoxide with a polyether polyol and heating the 
two together to form the polyepoxide resin. The polyether polyol is formed 
from reacting: 
(A) a cyclic polyol with 
(B) ethylene oxide or a mixture of ethylene oxide and an alkylene oxide 
having 3 to 8 carbon atoms in the alkylene chain. 
The equivalent ratio of (B) to (A) is within the range of 3 to 20:1. 
The invention also relates to aqueous dispersions containing the cationic 
resins prepared by the improved process, to a method of cationic 
electrodeposition using such aqueous dispersions, and to the coated 
articles derived therefrom. Cured electrodeposited coatings have better 
water, detergent and salt spray corrosion resistance, particularly when 
the coatings are cured at low temperature, than comparable coatings of the 
prior art. 
DETAILED DESCRIPTION 
The cationic resins of the present invention are non-gelled reaction 
products formed from contacting and heating together a polyepoxide with a 
polyether polyol, described in detail below, followed by reaction with a 
cationic base group former. 
The cationic resins of the invention have high rupture voltages and 
throwpower and deposit as films with improved flexibility. When compared 
with cationic products using polyester polyols such as described in U.S. 
Pat. No. 4,104,147, the products of the invention have improved salt spray 
corrosion resistance, particularly products which are cured at low 
temperature (300.degree.-325.degree. F. [149.degree.-163.degree. C.]). 
When compared with cationic products using polyalkylene ether polyols such 
as polypropylene glycol, polyoxyethylene glycol and polyoxytetramethylene 
glycol, as disclosed in U.S. Pat. Nos. 3,839,252 and 4,104,147, the 
products of the invention show improvement in alkali, water and salt spray 
corrosion resistance. 
The polyepoxides which are used in the practice of the invention are 
polymers having a 1,2-epoxy equivalency greater than one and preferably 
about two, that is, polyepoxides which have on an average basis two epoxy 
groups per molecule. The preferred polyepoxides are polyglycidyl ethers of 
cyclic polyols. Particularly preferred are polyglycidyl ethers of 
polyhydric phenols such as bisphenol A. These polyepoxides can be produced 
by etherification of polyhydric phenols with epihalohydrin or dihalohydrin 
such as epichlorohydrin or dichlorohydrin in the presence of alkali. 
Examples of polyhydric phenols are 2,2-bis(4-hydroxyphenyl)propane, 
1,1-bis(4-hydroxyphenyl)ethane, 2-methyl-1,1-bis-(4-hydroxyphenyl)propane, 
2,2-bis-(4-hydroxy-3-tertiarybutylphenyl)propane, 
bis-(2-hydroxynaphthyl)methane, 1,5-dihydroxy-3-naphthalene or the like. 
Besides polyhydric phenols, other cyclic polyols can be used in preparing 
the polyglycidyl ethers of cyclic polyol derivatives. Examples of other 
cyclic polyols would be alicyclic polyols, particularly cycloaliphatic 
polyols, such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 
1,2-bis(hydroxymethyl)cyclohexane, 1,3-bis(hydroxymethyl)cyclohexane and 
hydrogenated bisphenol A. 
Examples of other polyepoxides are polyglycidyl ethers of polyhydric 
alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, 
1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 
1,5-pentanediol and the like. 
The polyepoxides have molecular weights of at least 200 and preferably 
within the range of 200 to 2000, and more preferably about 340 to 2000. 
The polyether polyol which is contacted and heated with the polyepoxide is 
formed from reacting a cyclic polyol with ethylene oxide or optionally 
with a mixture of ethylene oxide and an alkylene oxide having 3 to 4 
carbon atoms in the alkylene chain. 
The polyether polyol is prepared by techniques known in the art. Typical 
reaction conditions are as follows: The cyclic polyol is charged to a 
reactor capable of maintaining pressure. If the cyclic polyol is a liquid 
or low melting solid, for example, cyclohexanedimethanol, it can be added 
to the reactor neat. If the cyclic polyol is a solid or a high viscosity 
liquid, it is preferably dissolved in a suitable solvent. For example, 
bisphenol A can be dissolved as a 50 percent solution in methyl isobutyl 
ketone. Resorcinol can be dissolved in water. A catalyst such as a 
tertiary amine, for example, N,N'-dimethylcyclohexylamine, or an alkali 
metal hydroxide, for example, sodium hydroxide or potassium hydroxide, is 
usually added to the reaction mixture in an amount of about 0.5 to 2 
percent by weight based on total weight of the reaction mixture. The 
cyclic polyol is heated to about 180.degree.-220.degree. F. 
(82.degree.-104.degree. C.) and the reactor pressured with nitrogen to 
about 40-60 pounds per square inch (psi). 
Ethylene oxide also under pressure, usually at about 80-100 psi, is fed 
into the reactor slowly in an incremental manner with cooling to remove 
the exothermic heat obtained when the ethylene oxide reacts with the 
cyclic polyol. Throughout the addition which lasts about 3 to 4 hours, the 
temperature of the reaction vessel is kept at about 
180.degree.-250.degree. F. (82.degree.-121.degree. C.). At the completion 
of the ethylene oxide addition, the reaction mixture is held for about 1 
to 2 hours at about 200.degree.-250.degree. F. (93.degree.-121.degree. C.) 
to complete the reaction. If solvent was present, it is stripped off and 
if sodium hydroxide or potassium hydroxide catalyst were used, they can be 
neutralized with acid, for example, phosphoric acid, and the salt filtered 
off. 
If a mixture of ethylene oxide and higher alkylene oxide is used, the 
reaction preferably proceeds first with the higher alkylene oxide and then 
with the ethylene oxide. 
Examples of the cyclic polyols which can be used are polyhydric phenols and 
cycloaliphatic polyols such as those mentioned above in connection with 
the preparation of the polyepoxides. Also, cyclic polyols such as the 
aromatic diols, resorcinol, the aryl-alkyl diols such as the various 
isomeric xylene diols and heterocyclic diols such as 1,4-piperizine 
diethanol can be used. 
As mentioned above, besides ethylene oxide, mixtures of ethylene oxide and 
an alkylene oxide containing from 3 to 6, preferably 3 to 4 carbon atoms 
in the alkylene chain can be used. Examples of such alkylene oxides are 
1-2-propylene oxide, 1-methyl-1,2-propylene oxide, 1,2-butylene oxide, 
butadiene monoepoxide, epichlorohydrin, glycidol, cyclohexane oxide and 
styrene oxide, with 1,2-propylene oxide being preferred. 
The cyclic polyol-alkylene oxide condensate is preferably difunctional or 
trifunctional, that is, it contains an average of 2 to 3 hydroxyl groups 
per molecule. Higher functional polyethers can be employed, although their 
use is not preferred because of gelation problems. An example of a higher 
functionality polyether would be the reaction product of a cyclic polyol 
such as sucrose with ethylene oxide. 
The equivalent ratio of cyclic polyol to alkylene oxide should be within 
the range of 1:3 to 20, preferably 1:3 to 15. When the ratio is less than 
1:3, the resultant coating has insufficient flexibility. When the ratio is 
greater than 1:20, the electrical resistivity of the film will be 
adversely affected resulting in lower rupture voltages and throwpower, and 
the cured films will have poorer salt spray corrosion resistance. 
The preferred cyclic polyol-alkylene oxide condensates used in the present 
invention are believed to have the following structural formula: 
EQU R--(OX).sub.m (OC.sub.2 H.sub.4).sub.n --OH].sub.Z 
where R is a cyclic radical, m is equal to 0 to 18, n is equal to 1 to 15, 
n plus m is equal to 1 to 20, X is an alkylene radical of 3 to 8 carbon 
atoms and Z is equal to 2 to 3. 
The polyepoxide and the polyether polyol can be contacted by simply mixing 
the two together optionally in the presence of solvent such as aromatic 
hydrocarbons, for example, toluene, xylene and ketones, for example, 
methyl ethyl ketone and methyl isobutyl ketone. The polyepoxide and the 
polyether polyol are heated together, preferably at a temperature of at 
least 75.degree. C., more preferably at least 90.degree. C. and most 
preferably about 100.degree. to 180.degree. C., usually in the presence of 
a catalyst such as 0.05 to 2 percent by weight tertiary amines or 
quaternary ammonium bases. The time the polyepoxide and polyether polyol 
are heated together will vary depending on the amounts contacted, how they 
are contacted, the degree of agitation, temperature, and the presence of 
catalyst. In general, when the polyepoxide and polyether polyol are 
contacted in an agitated reactor, they are heated for a time sufficient to 
increase the epoxy equivalency of the reaction mixture. Preferably, the 
epoxy equivalency should be increased at least 25, more preferably at 
least 50, and most preferably from about 75-150 percent over its original 
value; the epoxide equivalent being determined according to ASTM D-1652 
(gram of resin solids containing 1-gram-equivalent of epoxide). 
Preferably, the ratio of equivalents of active hydrogen, e.g., hydroxyl, in 
the polyether polyol to equivalents of 1,2-epoxy in the polyepoxide should 
be about less than 1, more preferably about 0.1 to about 0.8:1, most 
preferably 0.3 to 0.6:1. 
The polyepoxide and the polyether polyol are contacted and heated together 
to form a resinous reaction product or resin. Although the nature of the 
resinous reaction product is not completely understood, it is believed it 
is a mixture of about 15 to 45 percent by weight of a chain-extended 
polyepoxide, that is, polyepoxide molecules linked together with polyether 
polyol molecules and about 55 to 85 percent by weight of unreacted 
polyether polyol and unreacted polyepoxide or polyepoxide reacted with 
itself. 
The resinous reaction product is then reacted with a cationic group former, 
for example, an amine and acid. The amine can be a primary, secondary or 
tertiary amine and mixtures thereof. 
The preferred amines are monoamines, particularly hydroxyl-containing 
amines. Although monoamines are preferred, polyamines such as ethylene 
diamine, diethylene triamine, triethylene tetraamine, 
N-(2-aminoethyl)ethanolamine and piperizine can be used but their use in 
large amounts is not preferred because they are multifunctional and have a 
greater tendency to gel the reaction mixture than monoamines. 
Tertiary and secondary amines are preferred to primary amines because the 
primary amines are polyfunctional with regard to reaction to epoxy groups 
and have a greater tendency to gel the reaction mixture. When using 
polyamines or primary amines, special precautions should be taken to avoid 
gelation. For example, excess amine can be used and the excess can be 
vacuum stripped at the completion of the reaction. Also, the polyepoxide 
resin can be added to the amine to insure that excess amine will be 
present. 
Examples of hydroxyl-containing amines are alkanolamines, dialkanolamines, 
trialkanolamines, alkylalkanolamines, arylalkanolamines and 
arylalkylalkanolamines containing from 2 to 18 carbon atoms in the 
alkanol, alkyl and aryl chains. Specific examples include ethanolamine, 
N-methyl-ethanolamine, diethanolamine, N-phenylethanolamine, 
N,N-dimethylethanolamine, N-methyldiethanolamine and triethanolamine. 
Amines which do not contain hydroxyl groups such as mono, di and tri-alkyl 
amines and mixed alkyl-aryl amines and substituted amines in which the 
substituents are other than hydroxyl and in which the substituents do not 
detrimentally affect the epoxy-amine reaction can also be used. Specific 
examples of these amines are ethylamine, propylamine, methylethylamine, 
diethylamine, N,N-dimethylcyclohexylamine, triethylamine, 
N-benzyldimethylamine, dimethylcocoamine and dimethyltallowamine. Also, 
amines such as hydrazine and propylene imine can be used. Ammonia can also 
be used and is considered for the purposes of this application to be an 
amine. 
Mixtures of the various amines described above can be used. The reaction of 
the primary and/or secondary amine with the polyepoxide resin takes place 
upon mixing the amine with the product. The reaction can be conducted 
neat, or optionally in the presnce of suitable solvent. Reaction may be 
exothermic and cooling may be desired. However, heating to a moderate 
temperature, that is, within the range of 50.degree. to 150.degree. C., 
may be used to hasten the reaction. 
The reaction product of the primary or secondary amine with the polyepoxide 
resin attains its cationic character by at least partial neutralization 
with acid. Examples of suitable acids include organic and inorganic acids 
such as formic acid, acetic acid, lactic acid, phosphoric acid and 
carbonic acid. The extent of neutralization will depend upon the 
particular product involved. It is only necessary that sufficient acid be 
used to disperse the product in water. Typically, the amount of acid used 
will be sufficient to provide at least 30 percent of the total theoretical 
neutralization. Excess acid beyond that required for 100 percent total 
theoretical neutralization can also be used. 
In the reaction of the tertiary amine with the polyepoxide resin, the 
tertiary amine can be prereacted with the acid such as those mentioned 
above to form the amine salt and the salt reacted with the polyepoxide to 
form the quaternary ammonium salt group-containing resin. The reaction is 
conducted by mixing the amine salt and the polyepoxide resin together in 
the presence of water. Typically, the water is employed on the basis of 
about 1.75 to about 20 percent by weight based on total reaction mixture 
solids. 
Alternately, the tertiary amine can be reacted with the polyepoxide resin 
in the presence of water to form a quaternary ammonium hydroxide 
group-containing polymer which, if desired, may be subsequently acidified. 
The quaternary ammonium hydroxide-containing polymers can also be used 
without acid, although their use is not preferred. 
In forming the quaternary ammonium base group-containing polymers, the 
reaction temperature can be varied between the lowest temperature at which 
reaction reasonably proceeds, for example, room temperature, or in the 
usual case, slightly above room temperature, to a maximum temperature of 
100.degree. C. (at atmospheric pressure). At greater than atmospheric 
pressure, higher reaction temperatures can be used. Preferably, the 
reaction temperature ranges between about 60.degree. to 100.degree. C. 
Solvent for the reaction is usually not necessary, although a solvent such 
as a sterically hindered ester, ether or sterically hindered ketone may be 
used if desired. 
In addition to the primary, secondary and tertiary amines disclosed above, 
a portion of the amine which is reacted with the polyepoxidepolyether 
polyol product can be the ketimine of a polyamine. This is described in 
U.S. Pat. No. 4,104,147 in column 6, line 23, to column 7, line 23, the 
portions of which are hereby incorporated by reference. The ketimine 
groups will decompose upon dispersing the amine-epoxy reaction product in 
water resulting in free primary amine groups which would be reactive with 
curing agents which are described in more detail below. 
Besides resins containing amine salts and quaternary ammonium base groups, 
resins containing other cationic groups can be used in the practice of 
this invention. Examples of other cationic resins are quaternary 
phosphonium resins and ternary sulfonium resins as described in U.S. Pat. 
No. 3,894,922 and U.S. Pat. No. 3,959,106, both to Wismer and Bosso. 
However, resins containing amine salt groups and quaternary ammonium base 
groups are preferred and the amine salt group-containing resins are the 
most preferred. 
The extent of cationic group formation of the resin should be selected that 
when the resin is mixed with aqueous medium, a stable dispersion will 
form. A stable dispersion is one which does not settle or is one which is 
easily redispersible if some sedimentation occurs. In addition, the 
dispersion should be of sufficient cationic character that the dispersed 
resin particles will migrate towards the cathode when an electrical 
potential is impressed between an anode and a cathode immersed in the 
aqueous dispersion. 
In general, most of the cationic resins prepared by the process of the 
invention contain from about 0.1 to 3.0, preferably from about 0.3 to 1.0 
milliequivalents of cationic group per gram of resin solids. 
As indicated above, cationic resins of the present invention contain active 
hydrogens such as those derived from hydroxyl, primary and secondary amino 
which make them reactive at elevated temperatures with a curing agent. The 
curing agent which is used should be one which is stable in the presence 
of the cationic resin at room temperature but reactive with the active 
hydrogens at elevated temperatures, that is, from about 90.degree. to 
260.degree. C. to form a crosslinked product. Examples of suitable curing 
agents are aminoplast resins, capped isocyanates and phenolic resins such 
as phenol-formaldehyde condensates including allyl ether derivatives 
thereof. 
The preferred curing agents are the capped isocyanates and these are 
described in U.S. Pat. No. 4,104,147, column 7, line 36, continuing to 
column 8, line 37, the portions of which are hereby incorporated by 
reference. 
Sufficient capped polyisocyanate is present in the coating system such that 
the equivalent ratio of latent isocyanate groups to active hydrogens is at 
least 0.1:1 and preferably about 0.3 to 1:1. 
Besides the blocked or capped isocyanates, aminoplast resins can also be 
employed as curing agents in the practice of the present invention. 
Suitable aminoplasts for use with the reaction products are described in 
U.S. Pat. No. 3,937,679 to Bosso and Wismer in column 16, line 3, 
continuing to column 17, line 47, the portions of which are hereby 
incorporated by reference. As disclosed in the aforementioned portions of 
the '679 patent, the aminoplast can be used in combination with methylol 
phenol ethers. The aminoplast curing agents usually constitute from about 
1 to 60 and preferably 5 to 40 percent by weight of the resinous 
composition based on total weight of aminoplast and the reaction product 
of a polyepoxide and amine. Also, mixed curing agents such as mixtures of 
capped isocyanates and aminoplast resins can be used. 
The resins of the present invention are nongelled and are employed in the 
form of aqueous dispersions. The term "dispersion" as used within the 
context of the present invention is believed to be a two-phase, 
transparent, translucent or opaque aqueous resinous system in which the 
resin is the dispersed phase and water is the continuous phase. Average 
particle size diameter of the resinous phase is generally less than 10 and 
preferably less than 5 microns. The concentration of the resinous phase in 
the aqueous medium depends upon the particular end use of the dispersion 
and in general is not critical. For example, the aqueous dispersion 
preferably contains at least 0.5 and usually from about 0.5 to 50 percent 
by weight resin solids. By non-gelled is meant the reaction products are 
substantially free of crosslinking and have an intrinsic viscosity when 
dissolved in a suitable solvent. The intrinsic viscosity of the reaction 
product is an indication of its molecular weight. A gelled reaction 
product, on the other hand, since it has essentially infinitely high 
molecular weight, will have an intrinsic viscosity too high to measure. 
Besides water, the aqueous medium may contain a coalescing solvent. Useful 
coalescing solvents include hydrocarbons, alcohols, esters, ethers and 
ketones. The preferred coalescing solvents include alcohols, polyols and 
ketones. Specific coalescing solvents include isopropanol, butanol, 
2-ethylhexnol, isophorone, 4-methoxy-2-pentanone, ethylene and propylene 
glycol, and the monoethyl, monobutyl and monohexyl ethers of ethylene 
glycol. The amount of coalescing solvent is not unduly critical and is 
generally between about 0.01 and 40 percent by weight, preferably about 
0.05 to about 25 percent by weight based on total weight of the aqueous 
medium. 
In some instances, a pigment composition and, if desired, various additives 
such as plasticizers, surfactants or wetting agents are included in the 
dispersion. The pigment composition may be any of the conventional types, 
comprising, for example, iron oxides, lead oxides, strontium chromate, 
carbon black, coal dust, titanium dioxide, talc, barium sulfate, as well 
as color pigments such as cadmium yellow, cadmium red, chromium yellow and 
the like. The pigment content of the dispersion is usually expressed as 
pigment-to-resin ratio. In the practice of the invention, the 
pigment-to-resin ratio is usually within the range of 0.02 to 1:1. The 
other additives mentioned above are usually in the dispersion in amounts 
of 0.01 to 10 percent by weight based on total weight of resin solids. 
Also, soluble lead such as lead acetate may be added to the dispersion. 
See, for example, U.S. Pat. No. 4,115,226 to Zwack and Jerabek. 
When the aqueous dispersions as described above are employed for use in 
electrodeposition, the aqueous dispersion is placed in contact with an 
electrically conductive anode and an electrically conductive cathode with 
the surface to be coated being the cathode. Following contact with the 
aqueous dispersion, an adherent film of the coating composition is 
deposited on the cathode when a sufficient voltage is impressed between 
the electrodes. The conditions under which the electrodeposition is 
carried out are, in general, similar to those used in electrodeposition of 
other types of coatings. The applied voltage may be varied and can be, for 
example, as low as one volt to as high as several thousand volts, but 
typically between 50 and 500 volts. The current density is usually between 
0.5 ampere and 15 amperes per square foot and tends to decrease during 
electrodeposition indicating the formation of an insulating film. 
The aqueous resinous dispersions of the present invention can also be used 
in other conventional coating applications such as flow, dip, spray and 
roll coating applications. For electrodeposition and the other 
conventional coating applications, the coating compositions can be applied 
to a variety of electroconductive substrates especially metal such as 
steel, aluminum, copper, magnesium and the like, but also including 
metallized plastic and conductive carbon-coated materials. For the other 
conventional coating applications, the compositions can be applied to the 
non-metallic substrates such as glass, wood and plastic. 
After the coating has been applied by electrocoating or other conventional 
coating applications, it is cured usually by baking at elevated 
temperatures such as 90.degree. to 260.degree. C. for about 1 to 30 
minutes. 
Illustrating the invention are the following examples, which, however, are 
not to be construed as limiting the invention to their details. All parts 
and percentages in the examples as well as throughout the specification 
are by weight unless otherwise indicated.

VEHICLE RESINS 
Example A 
The following example shows the preparation of a cationic 
electrodepositable resin which was formed by contacting and heating 
together a polyglycidyl ether of bisphenol A with a bisphenol A-ethylene 
oxide adduct (1/10 molar ratio) to form a polyepoxide resin, followed by 
reacting the resin with a mixture of secondary amines. The amine reaction 
product is then combined with a blocked isocyanate crosslinking agent, 
partially neutralized with acid and dispersed in deionized water. The 
cationic electrodepositable resin was prepared from the following mixture 
of ingredients: 
______________________________________ 
Ingredients Parts by Weight 
Solids Equivalents 
______________________________________ 
EPON 829.sup.1 
727.6 702.1 3.735 
Adduct of bisphenol A- 
303.2 303.2 1.000 
ethylene oxide (1/10 
molar ratio) 
Xylene 37.8 
Bisphenol A 197.8 197.8 1.735 
Benzyldimethylamine 
3.6 
Blocked isocyanate 
1016.3 711.4 
crosslinker.sup.2 
Diketimine derivative.sup.3 
73.06 53.1 0.609 
N--methylethanolamine 
65.0 65.0 0.865 
1-phenoxy-2-propanol 
101.6 
______________________________________ 
.sup.1 Epoxy resin solution made from reacting epichlorohydrin and 
bisphenol A having an epoxy equivalent of 188 commercially available from 
Shell Chemical Company. 
.sup.2 Polyurethane crosslinker formed from halfcapping toluene 
diisocyanate (80/20 2,4/2,6-isomer mixture) with 2hexoxyethanol and 
reacting this product with trimethylolpropane in a 3:1 molar ratio. The 
crosslinker is present as a 70 percent solids solution in methyl isobutyl 
ketone and butanol (9:1 weight ratio). 
.sup.3 Diketimine derived from diethylenetriamine and methyl isobutyl 
ketone (73 percent solids in methyl isobutyl ketone). 
The EPON 829, bisphenol A-ethylene oxide adduct and xylene were charged to 
a reaction vessel and heated together with nitrogen sparge to 210.degree. 
C. The reaction was held at 200.degree.-215.degree. C. with refluxing to 
remove any water present. The ingredients were cooled to 150.degree. C. 
and the bisphenol A and 1.6 parts of the benzyldimethylamine (catalyst) 
added. The reaction mixture was heated to 150.degree. C. and held between 
150.degree. and 190.degree. C. for about 1/2 hour and then cooled to 
130.degree. C. The remaining portion of the benzyldimethylamine catalyst 
was added and the reaction mixture held at 130.degree. C. for about 21/2 
hours until a reduced Gardner-Holdt viscosity (50 percent resin solution 
in 2-ethoxyethanol) of H was obtained. Note, the reaction sequence is 
believed to be the EPON 829 reacting first with bisphenol A to form a 
polyepoxide with an epoxide equivalent of about 600, followed by heating 
with the bisphenol A-ethylene oxide adduct to an epoxide equivalent of 
about 990. The polyurethane crosslinker, the diketimine derivative and the 
N-methylethanolamine were then added and the temperature of the reaction 
mixture brought to 110.degree. C. and held at this temperature for one 
hour. The 1-phenoxy-2-propanol was added and then 2200 parts of the 
reaction mixture was dispersed in a mixture of 30.9 grams acetic acid, 
44.3 grams of the surfactant mixture described in Example B, infra, and 
2718 grams of deionized water. The solids content of the aqueous 
dispersion was 35.5 percent. This dispersion was then diluted to 32 
percent solids and the solvent removed by vacuum distillation at 
85.degree.-90.degree. C. The solids of the solvent stripped dispersion was 
about 36 percent. 
Example B 
A cationic electrodepositable resin similar to Example A was prepared with 
the exception that a bisphenol A-ethylene oxide condensate having a molar 
ratio of 1/7 was used. 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
EPON 829 114.0 
Bisphenol A-ethylene oxide adduct (1/7 
38.0 
molar ratio) 
Xylene 5.4 
Bisphenol A 31.0 
Benzyldimethylamine 0.6 
Crosslinker of Example A 
139.6 
Diketimine of Example A 11.9 
N--methylethanolamine 9.3 
1-phenoxy-2-propanol 14.7 
Acetic Acid 5.2 
Surfactant.sup.1 7.2 
Deionized water 408.0 
______________________________________ 
.sup.1 Cationic surfactant prepared by blending 120 parts of alkyl 
imidazoline commercially available from Geigy Industrial Chemicals as 
GEIGY AMINE C, 120 parts by weight of an acetylenic alcohol commercially 
available from Air Products and Chemicals Inc. as SURFYNOL 104, 120 parts 
by weight of 2butoxyethanol and 221 parts by weight of deionized water an 
19 parts of glacial acetic acid. 
The procedure for preparing the resinous composition was as generally 
described in Example A except that the EPON 829, bisphenol A and bisphenol 
A-ethylene oxide adduct were heated together to a reduced Gardner-Holdt 
viscosity of K instead of H. The increase in epoxy equivalent was from 
about 600 to 950. Ninety-seven and one-half (971/2) percent by weight of 
the resin was dispersed in the mixture of acetic acid, surfactant and 
deionized water as described in Example A. The organic solvent was removed 
by vacuum distillation as described in Example A. 
Example C 
The following example shows the preparation of a cationic 
electrodepositable resinous composition similar to Example A with the 
exception that a bisphenol A-propylene oxide-ethylene oxide adduct (1/2/4 
molar ratio) was employed. 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
EPON 828.sup.1 702.2 
Bisphenol A-propylene oxide-ethylene oxide 
243.1 
adduct (1/2/4 molar ratio) (OH value = 230) 
Xylene 60.2 
Bisphenol A 197.8 
Benzyldimethylamine 3.8 
Polyurethane crosslinker of Example A 
991.3 
Diketimine derivative of Example A 
72.5 
N--methylethanolamine 65.0 
1-phenoxy-2-propanol 97.7 
______________________________________ 
.sup.1 Epoxy resin solution made from reacting epichlorohydrin and 
bisphenol A having an epoxy equivalent of about 188, commercially 
available from Shell Chemical Company. 
The procedure for preparing the resinous composition was as generally 
described in Example A with the exception that the EPON 828, bisphenol A 
and bisphenol A-propylene oxide-ethylene oxide adduct were heated together 
to a Gardner-Holdt reduced viscosity of N-O. The increase in epoxy 
equivalent was from about 570 to 1024. The reaction mixture (2100 parts by 
weight) was dispersed in 30.6 parts of acetic acid and 42.2 parts of the 
surfactant mixture of Example B and 2564.6 parts of deionized water. The 
solvent was removed as described in Example A and the final dispersion had 
a solids content of 38.1 percent. 
Example D 
A cationic electrodepositable resinous composition similar to that of 
Example A was prepared with the exception that a resorcinol-ethylene oxide 
condensate (1/6.5 molar ratio) was used. 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
EPON 829 727.6 
Resorcinol-ethylene oxide (1/6.5 molar ratio) 
183.9 
(OH value = 305) 
Xylene 31.5 
Bisphenol A 197.8 
Benzyldimethylamine 3.6 
Polyurethane crosslinker of Example A 
946.8 
Diketimine derivative of Example A 
76.0 
N--methylethanolamine 65.0 
1-phenoxy-2-propanol 93.4 
______________________________________ 
The procedure for preparing the resinous composition was as generally 
described in Example A with the exception that the reaction was held for a 
reduced Gardner-Holdt viscosity of N. The increase in epoxy equivalent was 
from about 540 to 901. The reaction mixture (2000 parts) was dispersed in 
a mixture of 30.5 parts acetic acid, 40.2 parts of the surfactant mixture 
of Example B and 2459 parts of deionized water. The solvent was removed as 
described in Example A. The final dispersion had a solids content of 36.9 
percent. 
Example E 
A cationic electrodepositable resinous composition similar to Example A was 
prepared with the exception that a cyclohexanedimethanolethylene oxide 
adduct (1/6.5 molar ratio) was used. 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
EPON 828 702.2 
Cyclohexanedimethanol-ethylene oxide adduct 
183.9 
(1/6.5 molar ratio) 
Xylene 57.0 
Bisphenol A 197.8 
Benzyldimethylamine 3.6 
Polyurethane crosslinker of Example A 
945.4 
Diketimine derivative of Example A 
73.6 
N--methylethanolamine 65.0 
1-phenoxy-2-propanol 93.2 
______________________________________ 
The procedure for preparing the resinous composition was as generally 
described in Example A with the exception that the reaction was held for 
an R Gardner-Holdt reduced viscosity. The increase in epoxy equivalent was 
from about 540 to 949. The reaction mixture (2000 parts) was dispersed in 
a mixture of 30.5 parts acetic acid, 40.2 parts of the surfactant mixture 
of Example B and 2460 parts of deionized water. Th solvent was removed as 
described in Example A and the final dispersion had a solids content of 
36.9 percent. 
Example F 
A cationic (quaternary ammonium salt group) electrodepositable resinous 
composition was prepared by contacting and heating together a polyepoxide 
and a bisphenol A-ethylene oxide adduct (1/10 molar ratio), combining the 
product with a blocked isocyanate crosslinker, reacting with a tertiary 
amine acid salt and dispersing the reaction product in water. 
______________________________________ 
Parts 
Ingredients Solids Equivalents 
by Weight 
______________________________________ 
EPON 829 541.4 2.85 561.1 
Bisphenol A 176.6 1.54 176.6 
Xylene 4.9 
TEXANOL.sup.1 53.7 
Bisphenol A-ethylene oxide 
182.0 0.60 182.0 
adduct (1/10 molar ratio) 
Benzyldimethylamine 
2.0 2.0 
TEXANOL 26.7 
Lactic acid 3.3 3.8 
INDOPOL L-14.sup.2 
31.8 31.8 
2-phenoxyethanol 166.5 
Polyurethane crosslinker.sup.3 
353.7 525.6 
Lactic acid salt of 
33.5 0.168 44.7 
dimethylethanolamine.sup.4 
Lactic acid salt of 
75.5 0.335 100.6 
dimethylcyclohexylamine.sup.5 
GEIGY AMINE C 7.5 0.027 7.5 
Deionized water 70.0 
______________________________________ 
.sup.1 2,2,4trimethylpentane-1,3-diol monoisobutyrate commercially 
available from Eastman Chemical Company. 
.sup.2 Polybutene commercially available from Amoco Chemical Corp. 
.sup.3 2butoxyethanol fully blocked polymethylene polyphenyl isocyanate a 
a 68 percent solids solution in 2butoxyethanol. 
.sup.4 75 percent solids solution in isopropyl alcohol. 
.sup.5 75 percent solids solution in water. 
The EPON 829, bisphenol A and xylene were charged to a reaction vessel and 
heated under a nitrogen blanket to 150.degree. C. to initiate an exotherm. 
The reaction mixture was permitted to exotherm for about one hour with the 
highest temperature reaching 185.degree. C. The reaction mixture was 
cooled to 169.degree. C. followed by the addition of the bisphenol 
A-ethylene oxide adduct and the first portion of TEXANOL. The 
benzyldimethylamine was added and the reaction mixture was held between 
126.degree. and 134.degree. C. for about 5 hours until the reaction 
mixture had a reduced Gardner-Holdt viscosity (50/50 blend in 
2-ethoxyethanol) of P-Q. The increase in epoxy equivalent was from about 
550 to 1234. At that point, the second portion of TEXANOL, the lactic 
acid, the INDOPOL L-14, the polyurethane crosslinker, the 
2-phenoxyethanol, the dimethylethanolamine and dimethylcyclohexylamine 
lactate salts, the GEIGY AMINE C and the deionized water were added and 
the reaction mixture heated to 80.degree. C. and held for 2 hours. The 
reaction mixture was then thinned with deionized water to a solids content 
of 32 percent. The resinous dispersion contained 0.389 milliequivalents 
per gram solids of quaternary ammonium base groups. 
Example G 
A cationic electrodepositable resin similar to Example F was prepared with 
the exception that an adduct of bisphenol A-ethylene oxide (1/6 molar 
ratio) was used. 
______________________________________ 
Parts 
Ingredients by Weight 
______________________________________ 
EPON 829 561.1 
Bisphenol A 176.6 
Xylene 4.9 
TEXANOL 53.7 
Bisphenol A-ethylene oxide adduct (1/6 molar ratio) 
146.6 
Benzyldimethylamine 2.0 
TEXANOL 26.7 
Lactic acid 3.8 
INDOPOL L-14 31.8 
2-phenoxyethanol 166.5 
Polyurethane crosslinker.sup.1 
605.4 
Dimethylethanolamine lactic acid salt as used 
52.1 
in Example F 
Dimethylcyclohexylamine lactic acid salt as used 
84.1 
in Example F 
GEIGY AMINE C 7.5 
Deionized water 70.0 
______________________________________ 
.sup.1 Polyurethane crosslinker formed from halfcapping toluene 
diisocyanate (80/20 2,4/2,6-isomer mixture) with 2ethoxyethanol and 
reacting this product with trimethylolpropane in a 3:1 molar ratio. The 
polyurethane crosslinker is present as a 70 percent solids solution in 
2ethoxyethanol. 
The procedure for preparing the cationic resinous composition was as 
generally described in Example F. The increase in epoxy equivalent was 
from about 550 to 1220. The resinous mixture had a resin solids content of 
32 percent and contained 0.348 milliequivalents of quaternary ammonium 
base group per gram of resin solids. 
ADDITIVE 
Example H 
The following example shows the preparation of a 
polyepoxidepolyoxyalkylenediamine adduct. The adduct was made as an 
additive for subsequent addition to a cationic electrodeposition bath to 
provide better appearance in the cured coating. 
In preparing the adduct, a polyepoxide intermediate was first prepared from 
condensing EPON 829 and bisphenol A as follows: 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
EPON 829 136.1 
Bisphenol A 39.6 
2-butoxyethanol 
52.3 
______________________________________ 
The EPON 829 and bisphenol A were charged to a reaction vessel under a 
nitrogen blanket and heated to 70.degree. C. to initiate an exotherm. The 
reaction mixture was allowed to exotherm and held at 180.degree. C. for 
1/2 hour. The reaction mixture was cooled to 160.degree. C. and the 
2-butoxyethanol added to give a solids content of 75 percent and an epoxy 
equivalent of 438 (based on solids). 
A polyoxypropylenediamine having a molecular weight of 2000 and 
commercially available from Jefferson Chemical Company as JEFFAMINE D-2000 
was reacted with the polyepoxide intermediate described above as follows: 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
JEFFAMINE D-2000 132.7 
Polyepoxide intermediate 
67.4 
2-butoxyethanol 2.4 
Polyurethane crosslinker.sup.1 
174.5 
Acetic acid 3.9 
Surfactant of Example B 
7.4 
Deionized water 459.0 
______________________________________ 
.sup.1 Polyurethane crosslinker formed from halfcapping toluene 
diisocyanate (80/20 2,4/2,6-isomer mixture) with 2butoxyethanol and 
reacting this product with trimethylolpropane in a 3:1 molar ratio. The 
crosslinker is present as a 70 percent solids solution in methyl isobutyl 
ketone and butanol (9:1 weight ratio). 
The JEFFAMINE D-2000 was charged to a reaction vessel under a nitrogen 
atmosphere and heated to 90.degree. C. The polyepoxide intermediate was 
added over the period of about 1/2 hour. At the completion of the 
addition, the reaction mixture was heated to 130.degree. C., held for 3 
hours, followed by the addition of the 2-butoxyethanol and polyurethane 
crosslinker. The reaction mixture was then solubilized by blending with 
acetic acid, the surfactant and deionized water. The adduct had a solids 
content of 35.5 percent. 
Example I 
The adduct of Example H was combined with epsilon-caprolactam (for improved 
rheology) as follows: 
______________________________________ 
Ingredients Parts by Weight 
______________________________________ 
Adduct of Example H 
800.0 
Epsilon-caprolactam 
140.0 
Deionized water 260.0 
______________________________________ 
The caprolactam was heated to 80.degree. C. to melt it and mixed with the 
adduct. The mixture was then thinned with deionized water. 
PAINTS 
The following Examples (1-6) show the preparation of paints from the 
cationic electrodepositable coating vehicles, pigment pastes and additives 
described above. The paints were made by mixing the ingredients together 
with low shear agitation. The paints were electrodeposited onto various 
steel substrates. 
The wet films were cured at elevated temperatures, the thickness of the 
coatings measured and the cured coatings evaluated for water and salt 
spray corrosion resistance. The results are shown in Table I appearing at 
the end of Example 6. 
Example 1 
A cationic electrodepositable paint was prepared from the cationic resin of 
Example A. The resin was combined with a tin catalyst, pigmented with 
clay, basic lead silicate, carbon black, and strontium chromate, and 
thinned with deionized water. 
The paint in the form of an electrodeposition bath had a solids content of 
20 percent, a pigment-to-vehicle ratio of 0.2/1.0, a pH of 6.6 and a 
rupture voltage of 320 volts at ambient temperature. 
Zinc phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 78.degree. F. (26.degree. C.) for 2 
minutes at 200 volts. 
Example 2 
A cationic electrodepositable paint was prepared by blending 1430 grams of 
the cationic resin of Example A and 261 grams of the additive of Example 
I. The blend was combined with a tin catalyst, pigmented with clay, 
titanium dioxide, basic lead silicate and carbon black, and thinned with 
deionized water. 
The paint in the form of an electrodeposition bath had a solids content of 
20 percent, a pigment-to-binder ratio of 0.2/1.0 and a pH of 6.65. Zinc 
phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 250 volts (zinc phosphate) and 275 volts 
(untreated steel) for 2 minutes at a bath temperature of 78.degree. F. 
(26.degree. C.). 
Example 3 
A cationic electrodepositable paint was prepared by blending 1575 grams of 
the cationic resin of Example B and 174 grams of the additive of Example 
H. The blend was combined with a tin catalyst, pigmented with clay, 
titanium dioxide, basic lead silicate and carbon black, and thinned with 
deionized water. 
The paint in the form of an electrodeposition bath had a resin solids 
content of 20 percent, a pigment-to-binder ratio of 0.2/1.0. 
Zinc phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 225 volts for the zinc phosphate and 175 
volts for the untreated steel for 2 minutes at a bath temperature of 
78.degree. F. (26.degree. C.). 
Example 4 
A cationic electrodepositable paint was prepared by blending 1437 grams of 
the cationic resin of Example C and 174 grams of the additive of Example 
H. The blend was combined with a tin catalyst, pigmented with clay, 
titanium dioxide, basic lead silicate and carbon black, and thinned with 
deionized water. 
The paint in the form of a cationic electrodeposition bath had a resin 
solids content of 20 percent, a pigment-to-binder ratio of 0.2/1.0, a pH 
of 6.5 and a rupture voltage of 355 volts of 26.degree. C. The resin also 
had a GM throwpower of 111/4 inches measured at 300 volts at 26.degree. C. 
Zinc phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 250 volts at 26.degree. C. for 2 minutes. 
Example 5 
A cationic electrodepositable paint was prepared by blending 1482 grams of 
the cationic resin of Example D and 174 grams of the additive of Example 
H. The blend was combined with a tin catalyst, pigmented with caly, 
titanium dioxide, basic lead silicate and carbon black, and thinned with 
deionized water. 
The paint in the form of a cationic electrodeposition bath had a solids 
content of 20 percent, a pigment-to-binder ratio of 0.2/1.0, a pH of 6.5 
and a rupture voltage of 350 volts at 26.degree. C. Zinc phosphate 
pretreated and untreated steel panels were cathodically electrodeposited 
in the bath at 275 volts for 2 minutes at a bath temperature of 26.degree. 
C. 
Example 6 
A cationic electrodepositable paint was prepared by blending 1482 grams of 
the cationic resin of Example E and 174 grams of the additive of Example 
H. The blend was combined with a tin catalyst, pigmented with clay, 
titanium dioxide, basic lead silicate and carbon black, and thinned with 
deionized water. 
The paint in the form of a cationic electrodeposition bath had a solids 
content of 20 percent, a pigment-to-binder ratio of 0.2/1.0. Zinc 
phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 300 volts for 2 minutes at a bath 
temperature of 26.degree. C. 
TABLE 1 
__________________________________________________________________________ 
Curing Schedules and Evaluation of Cured Coatings of Examples 1-6 
for Salt Spray Corrosion Resistance.sup.1 and Water Resistance.sup.2 
Cure Scribe 
Temperature Time Creepage.sup.1 
Water Soak.sup.2 
Example 
.degree.F. 
(.degree.C.) 
(min.) 
Substrate (inches) 
Top Coat.sup.3 
Primer 
__________________________________________________________________________ 
1 325 
(163) 
20 zinc phosphate pretreated 
1/32 -- -- 
" " " untreated steel 
1/32 -- -- 
2 325 
(163) 
20 zinc phosphate pretreated 
&lt;1/32 9 10 
" " " untreated steel 
&lt;1/32 -- -- 
3 300 
(149) 
20 zinc phosphate pretreated 
&lt;1/32 6 10 
" " " untreated steel 
3/64 4 8 
3 325 
(163) 
20 zinc phosphate pretreated 
&lt;1/32 8 10 
" " " untreated steel 
1/32 8 9 
3 350 
(177) 
20 zinc phosphate pretreated 
&lt;1/32 4.sup.a 
10 
" " " untreated steel 
11/16 
7 9 
4 325 
(163) 
20 zinc phosphate pretreated 
&lt;1/32 8 10 
" " " untreated steel 
&lt;1/32 -- -- 
5 325 
(163) 
20 zinc phosphate pretreated 
&lt;1/32 5 10 
" " " untreated steel 
&lt;1/32 -- -- 
6 325 
(163) 
20 zinc phosphate pretreated 
&lt;1/32 5 10 
" " " untreated steel 
3/32 -- -- 
__________________________________________________________________________ 
.sup.1 Coated panels scribed with an "X" and exposed to a salt spray fog 
as described in ASTM D117. After 14 days, the panels were removed from th 
testing and the scribe mark taped with masking tape, the tape pulled off 
at a 45.degree. angle and the creepage from the scribe line measured. 
Creepage is the area where the coating has lifted from the panel surface. 
.sup.2 Coated panels soaked in water at 120.degree. F. (49.degree. C.) fo 
24 hours, removing the panel from the water, permitting it to stand at 
room temperature for 1 hour, followed by crosshatching the coated surface 
taping the crosshatch area with masking tape and pulling the masking tape 
off at a 45.degree. angle. Ratings were assigned a value of 1 to 10 
depending on how much coating was removed with the masking tape, with 1 
being the worst and 10 the best. 
.sup.3 The top coat was deposited from a nonaqueous dispersion acrylic 
polymer white coating composition available from Cook Paint and Varnish 
Company as WEA 5111. The coating composition as obtained was reduced with 
a 50/50 mixture of xylene and an aromatic blend of solvents having a 
boiling point of 155 to 184 so as to obtain a 17second viscosity measured 
with a No. 4 Ford cup. 
.sup.a Intercoat adhesion failure. 
Example 7 
A cationic electrodepositable paint was prepared by blending 1061.8 grams 
of the cationic resin of Example F with 386 grams of CYMEL 1156 which is 
an etherified melamine-formaldehyde commercially available from American 
Cyanamid Company. The blend was pigmented with carbon black, aluminum 
silicate and titanium dioxide, and thinned with deionized water. 
The paint in the form of an electrodeposition bath had a pigment-to-binder 
ratio of 0.4/1.0, and contained 15 percent by weight solids. Zinc 
phosphate pretreated and untreated steel panels were cathodically 
electrodeposited in the bath at 250 volts at a bath temperature of 
65.degree. F. (18.degree. C.). The wet films were baked at 400.degree. F. 
(204.degree. C.) for 20 minutes. The coated panels were subjected to 
testing for detergent resistance as provided by ASTM D-2248 and after 1150 
hours, the coatings retained good appearance. 
Example 8 
A cationic electrodepositable paint was prepared from the cationic resin of 
Example G. The resin was pigmented with carbon black, aluminum silicate 
and titanium dioxide, and thinned with deionized water. 
The paint in the form of an electrodeposition bath had a pigment-to-binder 
ratio of 0.4/1.0 and contained 15 percent by weight solids. 
Zinc phosphate pretreated steel panels were cathodically electrodeposited 
in the bath at 250 volts for 11/2 minutes at a bath temperature of 
80.degree. F. (27.degree. C.). The wet films were cured at 400.degree. F. 
(204.degree. C.) and subjected to detergent resistance testing as 
described above. After 528 hours, the coatings retained good appearance.