Resins of epoxy/aromatic diol copolymer and block copolymer of epoxy/aromatic diol copolymer and a epoxy-capped polybutadiene (co)polymer

The present invention provides a resin which is a mixture of (a) the product of a diol and one or more diepoxides and (b) an A-B-A block copolymer wherein A represents blocks of an epoxy/diol copolymer which is the reaction product of a diol and a diepoxide, and B represents blocks of an epoxy-capped, carboxyl-terminated polybutadiene or polybutadiene/acrylonitrile copolymer. Amine resins, produced by reaction of this resin with an amine are useful as the principal resin in electrocoating formulations which produce deposited films having excellent corrosion resistance and improved impact and chip resistance.

TECHNICAL FIELD 
The present invention relates to resins comprising mixtures of the reaction 
product of a diol and one or more diepoxides and A-B-A block copolymer 
resins which comprises blocks of oligomeric adducts of diols and 
diepoxides and blocks of epoxy-capped, carboxyl terminated polybutadiene 
or polybutadiene/acrylonitrile, to the amine resins thereof, and to 
compositions which can be used in electro-deposition baths to produce the 
corresponding hardened resins. 
BACKGROUND ART 
Cathodic electrodeposition of a film composed of an amine resin, 
crosslinker, pigment and other resinous components onto an electrically 
conductive article is an important industrial process. It constitutes the 
usual manner in which automobile, truck, and bus bodies as well as other 
large metallic surfaces are primed with paint. In addition to providing a 
painted surface, the resin systems employed protect the underlying metal 
surface from corrosion, impact damage and other detrimental exposure to 
environmental conditions. 
In performing the electrodeposition, the conductive article forms one 
electrode of a direct current circuit and is immersed in a coating ba made 
from an aqueous dispersion of the film-forming resin and other components. 
A direct electrical current is passed between the article and a 
counter-electrode contained in the electrodeposition bath. An electrical 
charge on the article causes the deposition of the resins and other 
components of the bath on the article so as to produce an electrodeposited 
film. The deposited film is then baked or otherwise hardened to yield a 
coating of substantially uniform thickness and protective characteristics. 
Generally, protection from the environment and other adverse conditions is 
accomplished by designing into the coating resins such chemical 
characteristics as adhesion, flexibility, strength, hardness, and 
inertness toward reaction with environmental chemicals. Each of the 
characteristics manifests itself in the protective properties of the 
hardened coating. 
A number of advances in the protective properties of electrodeposition 
systems have been described in the patent literature. For example U.S. 
Pat. Nos. 4,486,571; 4,513,125; 4,565,852; 4,617,348; 4,639,493; 
4,657,979; and 4,720,523, the disclosures of which are incorporated herein 
by reference, describe various dienemodified epoxy resins or cross-linking 
agents designed for the improvement of the properties of electrodeposition 
systems. 
One particular problem of electrodeposited films relates to impact and chip 
resistance. The electrodeposited film provides a first line of defense 
against corrosion of the underlying metal substrate, while simultaneously 
withstanding impact damage which results in chipping of the overlying 
decorative layers of coatings as well as delamination of the 
electrodeposited film from the underlying metal surface. The difficulty 
lies in chemically designing an electrocoat composition which maximizes 
both desired effects. Electrodeposited films which possess the requisite 
flexibility to withstand the shock of impact generally do not, at the same 
time, possess the required corrosion resistance nor adhere well to 
overlying layers of decorative coating and are thus more susceptible to 
chipping. Conversely, electrodeposited films which possess the desired 
adherence to other coating layers often are hard and do not respond well 
under impact. 
It is therefore an objective of the present invention to provide a 
principal resin system for use in electrodeposition coating which 
possesses both high corrosion resistance while simultaneously providing 
improved impact strength and excellent adherence to the substrate and 
conventional top coating films. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a resin which 
is a mixture of (a) the reaction product of a diol and one or more 
diepoxides, and (b) an A-B-A block copolymer wherein A represents blocks 
of an epoxy/diol copolymer which is the reaction product of a diol and one 
or more diepoxides; and B represents blocks of an epoxy-capped, 
carboxyl-terminated polybutadiene or polybutadiene/acrylonitrile 
copolymer. 
The resin has a weight per epoxide (WPE) of between about 1000 and 3000, 
and comprises from about 5% to about 25% by weight B block content, based 
on total resin. When reacted with an amine to produce an amine resin, the 
resins of this invention are useful as principal resins in aqueous 
electrocoat formulations and result in deposited electrocoat films having 
excellent corrosion resistance and improved impact and chip resistance. 
DETAILED DESCRIPTION AND BEST MODE FOR CARRYING OUT THE INVENTION 
The electrocoat compositions of the present invention comprise a principal 
resin emulsion; a grind resin formulation comprising a grind resin, one or 
more pigmenting agents; and one or more cross-linking agents. 
Principal Resin 
The principal resins of the present invention comprises a mixture of (a) 
the reaction product of a diol and one or more diepoxides, and (b) an 
A-B-A block copolymer in which A represents blocks of an epoxy/diol 
copolymer and B represents blocks of an expoxy-capped, carboxyl-terminated 
polybutadiene or polybutadiene/acrylonitrile copolymer. 
The A blocks of the principal resin comprise a copolymers of diol and 
diepoxide. The diepoxide is selected from diepoxide E.sup.1, diepoxide 
E.sup.2, and mixtures of diepoxides E.sup.1 and E.sup.2 wherein the amount 
of diepoxide E.sup.1 in the mixture ranges from 0% to 100%. 
The principal resins possess an equivalent weight per epoxide (WPE) of 
between about 1000 and about 3000, preferably between about 1200 and about 
1600. To optimize impact resistance and intercoat adhesion of the final 
principal resin, the percentage polybutadiene or 
polybutadiene/acrylonitrile B blocks in the resins lies between about 5 
weight percent and 25 weight percent, preferably about 15 weight percent 
of the total resin. The B blocks may be blocks of epoxy-capped, 
carboxyl-terminated butadiene homopolymer, or may be blocks of 
epoxy-capped, carboxyl-terminated butadiene/acrylonitrile copolymer. In 
the latter instance, the amount of acrylonitrile present in the 
butadiene/acrylonitrile copolymer blocks may range up to about 40%, 
preferably about 10-20%. 
The principal resins of this invention are prepared generally by reacting 
the following ingredients: 
(a) a diol 
(b) an epoxide-capped polybutadiene or polybutadiene/acrylonitrile 
copolymer 
(c) one or more diepoxides 
so as to achieve the desired WPE of about 1000 to about 3000, preferably 
about 1200 to about 1600 and a B block content of the total resin from 
about 5 weight percent to about 25 weight percent, preferably about 15 
weight percent. 
The formation of the resin proceeds by reaction of the terminal epoxy 
groups of the epoxy-capped, carboxyl terminated polybutadiene or 
polybutadiene/acrylonitrile starting material with the diol and diepoxide 
in the mixture to form the A-B-A block copolymer. Simultaneously, a 
separate reaction occurs between the diol and diepoxide to form a 
diol/epoxide polymer. The final resin is thus a mixture of the diol/epoxy 
polymers and the A-B-A block copolymers. 
The amounts of each starting material employed to achieve these desired 
results depends upon a number of interrelated factors and may be arrived 
at in each instance by resorting to the following steps of calculation: 
Step 1--Decide upon the weight of principal resin (G) to be produced. 
Step 2--Decide upon the weight of epoxy-capped, carboxyl-terminated 
polybutadiene or polybutadiene/acrylonitrile copolymer (P) to be used. 
(This figure reflects the weight percent of the total finished resin which 
is contributed by the B block and will depend upon both the percent B 
block desired in the final principal resin and the percent polybutadiene 
or polybutadiene/acrylonitrile in the starting material employed.) 
Step 3--Determine by conventional chemical means (such as titration) the 
WPE of the epoxy-capped, carboxyl-terminated polybutadiene or 
polybutadiene/acrylonitrile copolymer (W). 
Step 4--Determine by conventional chemical means (such as titration) the 
WPE of the diepoxide (D). If a mixture of two diepoxides E.sup.1 and 
E.sup.2 is used, a weighted average of the two WPE values is used. 
Step 5--Determine the equivalent weight of the diol (F). 
Step 6--Decide upon the desired final WPE for the principal resin (H). 
Step 7--Calculate the excess of equivalents of epoxide group over diol in 
the mixture (I): I=G/H 
Step 8--Calculate the number of equivalents (J) of epoxy-capped, 
carboxyl-terminated polybutadiene or polybutadiene/acrylonitrile 
copolymer: J=P/W. 
Step 9--Calculate the weight of diol plus diepoxides to be used in the 
reaction mixture (K): 
EQU K=G-P. 
Step 10--Calculate the number of equivalents of diepoxide (L) in the 
reaction mixture: 
EQU L=F+D. 
Step 11--Calculate the weight of diepoxide to be used in the reaction 
mixture (C) 
##EQU1## 
Step 12--Calculate the weight of diol (E) to be used in the reaction 
mixture: E=G-P-C 
The following example is merely illustrative of the use of the 
computational method detailed above in the preparation of a principal 
resin in accordance with this invention. In this illustrative example, the 
following assumption are made: 
Step 1--A batch of 1000 g of principal resin is to be made. G=1000 g. 
Step 2--The desired polybutadiene/acrylonitrile content of the final 
polymer is to be 15 weight percent. The starting material selected is 
Wilmington Chemical Company WC-8006 which contains 40 weight percent 
polybutadiene/acrylonitrile copolymer and 60% diglycidyl ether of 
bisphenol A as reactant/diluent. 
##EQU2## 
Step 3--The WPE of the epoxy-capped, carboxyl-terminated polybutadiene or 
polybutadiene/acrylonitrile copolymer is determined experimentally to be 
350: W=350. 
Step 4--For this example, a 50%/50% mixture of diepoxide E.sup.1 having a 
WPE of 125 and diepoxide E.sup.2 having a WPE of 350 is selected. The WPE 
for the mixture is taken to be the average of the two, 237.5. Thus D=237.5 
and 
EQU L=F+D=55+237.5=292.5 
Step 5--For this example, the diol chosen is hydroquinone, equivalent 
weight=55: F=55. 
Step 6--The desired WPE of the final resin is 1200: H=1200. 
Step 7--I=G/H=1000/1200=0.833 
Step 8--J=P/W=375/350=1. 071 
Step 9--K=G-P=1000-375=625 
Step 10--L=F+D=55+237.5=292.5 
##EQU3## 
The reaction mixture for the example illustrated above would thus initially 
contain 375 g of WC-8006 (of which 225 g comprises the diglycidyl ether of 
bisphenol A and 150 g comprises epoxy-capped, carboxyl-terminated 
polybutadiene/acrylonitrile copolymer); ob 496.9 g of a mixture of 
diepoxide E.sup.1 and diepoxide E.sup.2 and 128.1 g of hydroquinone. The 
resulting resin will comprise about 15 weight percent B block 
polybutadiene/acrylonitrile copolymer. 
General Synthetic Method for Preparing the Principal Resin 
The reaction is carried out generally by charging the reaction vessel with 
the epoxy-capped, carboxyl-terminated polybutadiene or 
polybutadiene/acrylonitrile prepolymer, the diepoxide or mixture of 
diepoxides, the diol, and a non-polar, aprotic solvent such as toluene. 
The reaction mixture is slowly heated with mechanical stirring to a 
temperature of about 120.degree. C. under a flow of nitrogen gas. When a 
temperature of about 120.degree. C. is reached, about 0.05 weight percent 
of triphenylphosphine catalyst is added to the reaction vessel contents to 
catalyze the reaction. At this point, the reaction mixture generally 
undergoes an exothermic reaction and the temperature is maintained at or 
below about 160.degree. C. When the initial exothermic reaction has 
subsided, the mixture is again heated to maintain the temperature at about 
150.degree. C. Samples are withdrawn periodically from the reaction 
mixture and the WPE of the mixture is determined. When the desired WPE 
value has been reached, typically after about three hours reaction time, 
the temperature of the mixture is reduced to about 90.degree. C. 
The desired end-capping amine of the principal resin is then added to the 
reaction vessel contents, and the temperature of the resulting exothermic 
reaction is kept below about 15.degree. C. with cooling. When the 
exothermic reaction has subsided, the mixture is heated for an additional 
one hour at a temperature of about 100.degree.-110.degree. C. At the end 
of this time, the mixture is cooled and an appropriate solvent such as 
methyl iso-butyl ketone is added and the product is removed from the 
reaction vessel and allowed to cool to room temperature. 
Starting Materials-Diol 
The epoxy/diol copolymer blocks are formed by reacting one or more 
diepoxides with a diol. Diols which are useful for this purpose are 
generally selected from phenolic alcohols. By the term phenolic alcohols 
as used throughout this specification and appended claims is meant any 
compound in which the hydroxyl functional group is directly attached to an 
aromatic carbocyclic ring or a substituted aromatic carbocyclic ring. 
Compounds which may be employed in the formulation of the epoxy/diol 
copolymer blocks of the principal resin are selected from bis-(hydroxy 
aryl) alcohols, and monoaryl diols. 
Examples of bis-(hydroxy aryl) alcohols include those compounds in which 
two hydroxyl groups are attached to Ar.sup.1, where Ar.sup.1 is defined as 
two or more aromatic carbocyclic rings which are fused, are connected by a 
valence bond, or are connected by a branched or unbranched divalent 
alkylene group containing from 1 to 3 carbon atoms or carbonyl. The group 
Ar.sup.1 may be optionally further substituted with alkyl of from one to 
four carbon atoms, alkoxy of from one to four carbon atoms, phenyl, 
alkylphenyl in which the alkyl group contains from one to four carbon 
atoms, or halogen. 
Representative compounds include 1,5-, 1,6-, 1,7-, 1,8-, 2,5-, 2,6-, 2,7-, 
and 2,8-dihydroxyanthracene; 1,5-, 1,6-, 1,7-, 1,8-, 2,5-, 2,6-, 2,7-, and 
2,8-dihydroxy-naphthalene, 2,2'-, 2,3'-, 2,4'-, 3,3'-, 3,4'-, and 
4,4'-dihydroxybiphenyl; and 2,2"-, 2,3"-, 2,4"-, 3,3"-, 3,4"-, and 
4,4"-dihydroxyterphenyl, bis-(hydroxyphenyl)methane, 
bis-(hydroxyphenyl)ethane, bis-(hydroxyphenyl)propane, bisphenol A, 
p,p'-dihydroxy-benzophenone, or any of the foregoing substituted by 
methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, 
tert-butyl, methoxyl, ethoxyl, n-propoxyl, iso-propoxyl, n-butoxyl, 
iso-butoxyl, sec-butoxyl, tert-butoxyl, or halogen. 
Monoaryl diol alcohols which may be employed in the synthesis of the 
epoxy/diol copolymer blocks of the principal resins of the present 
invention comprise compounds in which two hydroxyl groups are attached to 
Ar.sup.2 where Ar.sup.2, is defined as a phenylene group or phenylene 
group substituted with alkyl, alkoxyl of from one to four carbon atoms, 
phenyl, alkylphenyl in which the alkyl group contains from one to four 
carbon atoms, or halogen. Representative compounds of this class include 
resorcinol, hydroquinone, and catechol, as well as substituted forms 
thereof. Preferred diols are hydroquinone and bisphenol A. 
Starting Materials--Diepoxide 
The diepoxide compounds useful for formulating the epoxy/diol copolymer 
blocks of the principal resins of this invention are selected from either 
of two general classes or mixtures thereof. One class of diepoxide, 
E.sup.1, comprises compounds having the structure 
##STR1## 
wherein Ar.sup.3 is selected from the group selected from Ar.sup.1 and 
Ar.sup.2 as defined above. Preferred diepoxides of class E.sup.1 are the 
diglycidyl ether of bisphenol A and the diglycidyl ether of hydroquinone. 
The second class of diepoxide, E.sup.2, comprises compounds having the 
structure 
##STR2## 
wherein Ar.sup.3 is as defined above and R is alkyl of from one to six 
carbon atoms or alkoxyalkyl of from two to twelve carbon atoms. A 
preferred diepoxides of class E.sup.2 useful in the practice of this 
invention is 2,2-bis-[p-(3-butoxy-2-glycidyloxypropyloxy)phenyl]propane. 
This corresponds to compound E.sup.2 in which Ar.sup.3 is 
2,2-diphenylpropane and R is n-butyl. 
The synthesis of the diepoxide compounds of class E.sup.1 follow procedures 
generally known in the art. Epihalohydrins such as epichlorohydrin, 
epibromohydrin, or epiiodohydrin are reacted with the desired diol 
precursor to form the bis-glycidyl ether. The reaction is generally 
carried out in a polar, aprotic solvent in the presence of an acid 
scavenger such as aqueous sodium hydroxide or similar hydroxide base under 
about stoichiometric proportions and at a temperature of from about 
0.degree. C. to about 100.degree. C., preferably at about ambient 
temperature. 
Diepoxide compounds of class E.sup.2 are prepared by methods detailed in 
U.S. Pat. No. 4,284,574, the disclosure of which is incorporated herein by 
reference. The process involves first reacting two moles of an alcohol or 
alkoxy alcohol with one mole of the desired diglycidyl ether of formula 
E.sup.1 above This step is carried out in the presence of a basic catalyst 
such as a tertiary amine, a quaternary ammonium salt, or an alkali metal 
hydroxide, generally at temperatures between about 80.degree. C. and 
180.degree. C. in the absence of a solvent. 
The product of this reaction is then further reacted with about 1.8 to 2.2 
moles of epichlorohydrin in the presence of a Lewis acid catalyst such as 
stannic chloride, or boron trifluoride or a complex thereof. This reaction 
results in a bis-chlorohydrin which is then reacted with sodium hydroxide 
in the usual manner to form the diepoxides of formula E.sup.2 above. 
Starting Materials--Epoxy-Capped, Carboxyl-Terminated Polybutadiene or 
Polybutadiene/Acrylonitrile Prepolymers 
In the principal resin of this invention, the B blocks comprise 
epoxy-capped, carboxyl-terminated polybutadiene or carboxyl-terminated 
polybutadiene/acrylonitrile copolymer having a number average molecular 
weight in the range of about 3000-4000 and in which the carboxyl groups 
have been further reacted with the diglycidyl ether of bisphenol A. These 
prepolymers are prepared by reacting carboxyl-terminated polybutadiene or 
carboxyl-terminated polybutadiene/acrylonitrile copolymers with an excess 
of the diglycidyl ether of bisphenol A so that no free carboxyl groups 
remain at the end of the reaction. The resulting material is thus a 
mixture of the epoxy end-capped prepolymer and free bisphenol A as a 
diluent/reactant. 
The carboxyl-terminated polybutadiene and polybutadiene/acrylonitrile 
copolymers useful as starting materials in the preparation of the B block 
prepolymers are commercially available as Hycar.RTM. resins from B.F. 
Goodrich Specialty Polymers & Chemicals Division, 6100 Oak Tree Blvd , 
Cleveland, Ohio. These carboxyl-terminated Hycar.RTM. resins comprise 
butadiene and acrylonitrile which are copolymerized to form a copolymer in 
which the weight percentage acrylonitrile, based on total polymer weight, 
ranges from 0% to 26% and has a number average molecular weights in the 
range of from about 3200 to about 4200. Hycar.RTM. resins useful in the 
practice of this invention are listed in Table 1. 
TABLE 1 
______________________________________ 
Number Average 
Molecular Weight 
Acrylonitrile Content 
Hycar .RTM. Resin 
Mn (Percent) 
______________________________________ 
CTB 2000X165 
3,800 0 
CTB 2000X162 
4,200 0 
CTBN 1300X31 
3,800 10 
CTBN 1300X8 
3,600 18 
CTBN 1300X13 
3,200 26 
CTBN 1300X9 
3,600 18 
______________________________________ 
The preferred starting material for preparing the expoxy-capped, B 
copolymer blocks of the principal resins of this invention are 
carboxyl-terminated polybutadiene/acrylonitrile copolymers having from 
about 15% to about 25% acrylonitrile content. A particularly preferred 
material is Hycar.RTM. CTBN 1300X8, having an acrylonitrile content of 
about 18%. 
As stated above, the carboxyl-terminated polybutadiene or 
carboxyl-terminated polybutadiene/acrylonitrile copolymers listed above 
are end-capped by reaction with an excess of diepoxide such as the 
diglycidyl ether of bisphenol A. The resulting prepolymers are 
commercially available from Wilmington Chemical Corporation, P.O. Box 66, 
Wilmington, Del. 19899, and contain varying amounts of excess diglycidyl 
ether of bisphenol A is a diluent/reactant. Preferred resins of this type 
useful in the practice of this invention are listed in Table 2. 
TABLE 2 
______________________________________ 
Wilmington Percent DGEBA in 
Resin Hycar .RTM. Resin 
Mixture 
______________________________________ 
WC-8005 CTBN 1300X13 
60 
WC-8006 CTBN 1300X8 60 
______________________________________ 
Starting Materials--End-Capping Amines 
Amines useful for end-capping the resins of this invention, leading to the 
formation of amine resins, include ammonia, and mono- and poly- primary, 
secondary, and tertiary amines as well as mono- and polyamines which 
contain mixtures of primary, secondary, and tertiary amine groups. 
Heterocyclic amines and physical mixtures or chemical mixtures of these 
amines may also be used. Optionally, these amines may contain other 
chemical functional groups such as hydroxyl, amide, carboxylic acid, 
ether, thiol, thioether, or alkoxyl groups. The amine preferably contains 
from one to five amine groups. When tertiary amine groups are present, it 
is preferable that primary or secondary amine groups are also present. 
The organic radicals substituting the mono- or poly-primary, secondary or 
tertiary amines may be aliphatic, unsaturated, alicyclic, aromatic 
carbocyclic, aliphatic-substituted aromatic, aromatic-substituted 
aliphatic, or heterocyclic in nature. Generally, the aliphatic or 
unsaturated radicals are of from one to ten carbon atoms. Aromatic 
radicals include mono- or polyphenylene groups or naphthalene groups, any 
of which may be optionally substituted with one or more lower alkyl or 
lower alkoxy groups. 
When polyamines are employed, amine groups may both terminate the amine 
compound and may be present within the chain structure of the amine 
compound. Exemplary of suitable aliphatic and alicyclic diamines useful 
for forming amine resins of the present invention include 1,2-ethylene 
diamine; 1,2-propylene diamine; 1,8-menthane diamine; isophorone diamine; 
propane-2,2-cyclohexyl amine; and triethylene tetramine. 
Mixed amines in which the radicals are of different types may also be 
employed as, for example, with mixed aromatic and aliphatic radicals. 
Other functional groups, such as alkyl, alkoxy, hydroxyl, halo-, or 
nitroso may also optionally be attached to the organic radicals. 
Aromatic diamines such as phenylene diamines and toluene diamines can be 
employed as, for example, p-phenylene diamine, p-toluenediamine. N-alkyl 
and N-aryl derivatives of the above types of amines may also be employed 
as, for example, N,N-dimethyl-o-phenylene diamine, 
N,N-di-p-tolyl-m-phenylene diamine and p-aminodiphenylamine. 
Polynuclear aromatic diamines may also be employed in which the aromatic 
rings are attached by means of a valence bonds as, for example in 
4,4'-biphenyl diamine, methylene dianiline, and monochloromethylene 
dianiline. 
Besides the amines mentioned above, hydrazines, hydrazides, aminoalcohols, 
mercapto-terminated derivatives of amine, and amino acids may also be 
employed. Examples of the foregoing include monoethanolamine, 
p-aminobenzoic acid, aminopropionic acid, N-(hydroxyethyl)ethylene 
diamine, anthranilic acid, p-aminophenol, aminostearic acid, and 
.beta.-aminobutyric acid. When amino acids are used as the amine to form 
amino resins of this invention, the conditions should be adjusted to 
release reactive amine groups from Zwitterionic complexes. 
Further amines which can be used to prepare amino resins of this invention 
include dialkylmonoamines of from 1 to 6 carbon atoms in each alkyl group; 
hydroxyalkyl alkyl amines and dihydroxyalkyl amines having from 1 to 6 
carbon atoms in each alkyl or hydroxyalkyl group; di-, tri-, tetra-, and 
pentaamines optionally substituted with alkyl groups of from 1 to 6 carbon 
atoms; aralkyl amines such as benzyl amine; alkyl-substituted aralkyl 
amines such as methylbenzyl amine; alkyl-substituted aromatic amines such 
as alkyl-substituted anilines in which the alkyl group contains from 1 to 
6 carbon atoms; and nitrogen heterocyclic compounds such as pyridine, 
morphline, quinoline, and the like. 
The syntheses of the amine resins by addition of the amine group containing 
compound to the polybutadiene/acrylonitrile modified epoxy resins of this 
invention follow any of three general synthetic process known in the art. 
These include the conventional "stoichiometric amine" addition procedure, 
the "excess amine" procedure and the "diketimine" procedure. 
In the conventional stoichiometric procedure, approximately stoichiometric 
amounts of the desired amine compound or compounds and the epoxide are 
combined in an inert, water-miscible organic solvent or an organic solvent 
mixture such as alcohol, methyl iso-butyl ketone, xylene, toluene, or 
glycol ethers, and gently heated to produce amine addition to the terminal 
epoxy groups of the epoxide compound. This procedure is well known in the 
art; see, for example, U.S. Pat. Nos. 3,984,299 and 4,031,050, the 
disclosures of which are incorporated herein by reference. 
In the so-called excess amine procedure, approximately and 8- to 10-fold 
excess (on a molar basis) of the desired amine is combined with the 
epoxide compound in an aprotic, non-polar solvent and gently heated to 
effect addition of the amine to the terminal epoxy groups of the epoxide 
compound. In this procedure, the presence of excess amine promotes the 
addition of primary amines and suppresses the self-addition of the 
resulting amine resin to as yet unreacted epoxide compound. Upon 
completion of the reaction, the excess amine is removed by convention 
vacuum distillation or similar technique. This procedure is known in the 
art; see, for example, U.S. Pat. Nos. 4,093,594; 4,116,900; 4,134,864; and 
4,137,140, the disclosures of which are incorporated herein by reference. 
In the diketimine procedure, a polyamine is typically used where primary 
and secondary amine groups are protected as ketimine groups by prior 
reaction with a ketone. The secondary amine groups of the diketimine with 
the terminal epoxy groups of the epoxide compound. In this procedure, an 
amount of diketimine is used which is approximately stoichiometrically 
equivalent to the epoxy groups in the epoxide. The mixture is gently 
heated to effect the reaction, after which the remaining primary ketimine 
groups are removed by acid hydrolysis upon standing in aqueous acid. This 
procedure is known in the art; see, for example, U.S. Pat. No. 3,947,339, 
the disclosure of which is incorporated herein by reference. 
Preparation of Principal Resin Emulsions 
The principal resin emulsions of the present invention comprise a mixture 
of the foregoing amine resins, one or more cross-linking agents, and a 
solubilizing portion of aqueous acid. The preferred weight ratio of amine 
resins to cross-linking agents in the principal resin emulsions are from 
about 2:3 to about 5 1. The amount of water added to this combination of 
amine resins and cross-linking agents is an amount sufficient to provide a 
solids content of from about 10% to about 65% by weight. 
Cross-Linking Agents 
The cross-linking agents used in the principal emulsions of the present 
invention are blocked organic polyisocyanates or poly(.beta.-hydroxy or 
.beta.-alkoxy)esters or other activated polyester compounds, aminoplast 
resins or phenoplast resins. In the practice of this invention, blocked 
organic polyisocyanates are preferred as the cross-linking agents. 
All of these cross-linking agents are compounds which are stable at room 
temperature but, when heated, decompose into compounds which have 
functional groups which are highly reactive toward hydroxyl groups and 
amine groups. These cross-linking agents contain a multiple number of such 
blocked functional groups and react multiple times, upon heating, with the 
amine resins during curing or hardening so as to cross-link the resins 
into three-dimensional matrices. 
Typical aminoplast and phenoplast resins which can be used as cross-linking 
agents in the practice of this invention are known in the art; see, for 
example U.S. Pat. No. 4,139,510, the disclosure of which is incorporated 
herein by reference. 
Suitable aminoplast resins are compounds which are the reaction product of 
ureas and melamines with aldehydes which are further etherified with an 
alcohol. Examples of aminoplast components are urea, ethylene urea, 
thiourea, melamine, benzoguanamine, and acetoguanamine. Aldehydes which 
are useful for reaction with ureas and melamines to form these aminoplast 
resins include formaldehyde, acetaldehyde, and propionaldehyde. The 
reaction of the ureas or melamines with the aldehydes produce methylol 
compounds which can be used as such as cross-linking agents in the present 
invention. However, it is preferred that the methylol compounds be further 
etherified with alcohols prior to use as cross-linking agents. Suitable 
alcohols for etherification of the aminoplast methylols are monoalcohols 
of from 1 to 8 carbon atoms. 
Suitable etherified aminoplast resins useful as cross-linking agents in the 
present invention include such compounds as methylol urea-formaldehyde 
resins, hexamethoxymethyl melamine, methylated polymeric 
melamine-formaldehyde resins, and butylated polymeric 
melamine-formaldehyde resins. 
In general, aminoplast resins and their methods of preparation are 
described in detail in "Encyclopedia of Polymer Science and Technology," 
Vol. 2, pages 1-19, Interscience Publishers, (1965), which is incorporated 
herein by reference. 
Phenoplast resins which are useful as cross-linking agents in the present 
invention include the reaction products of phenols and aldehydes which 
contain reactive methylol groups. The compositions can be monomeric or 
polymeric, depending upon the molar ratio of phenol and aldehyde used in 
the initial condensation reaction. Examples of phenols which can be used 
to make phenoplast cross-linking resins include o-, m-, or p-cresol, 
2,4-xylenol, 3,4-xylenol, 2,5-xylenol, cardanol, p-tertbutylphenol, and 
the like. Aldehydes useful in this reaction are formaldehyde, 
acetaldehyde, and propionaldehyde. Particularly useful as phenoplast 
cross-linking resins are polymethylol phenols where the phenolic group is 
etherified with a lower alkyl group. Phenoplast resins and their methods 
of preparation are described in detail in the "Encyclopedia of Polymer 
Science and Technology," Column 10, pages 1-68, Interscience Publishers 
(1969), which is incorporated herein by reference. 
Sufficient quantities of aminoplast and phenoplast resins are used in 
cathodic electrocoat compositions of the present invention to effect 
sufficient cross-linking of the polybutadiene/acrylonitrile modified 
epoxide resins upon baking or curing. Typically, the amount of aminoplast 
of phenoplast resin used in the practice of this invention is about 15 
weight % to about 40 weight %, preferably between about 20 and 40 weight 
%. 
The preferred cross-linking agents of this invention are organic 
polyisocyanates and, in particular, blocked polyisocyanates. The organic 
polyisocyanates and blocking agents used in the practice of this invention 
are typical of those used in the art; see, for example U.S. Pat. No. 
4,182,831, the disclosure of which is incorporated herein by reference. 
Useful blocked polyisocyanates are those which are stable in the 
electrodeposition compositions and baths of this invention at ambient 
temperature but which unblock and react with the amine resins of this 
invention at elevated temperature. 
In the preparation of blocked polyisocyanates useful as cross-linking 
agents in the practice of this invention, any suitable organic 
polyisocyanate can be used. Representative examples are aliphatic 
polyisocyanates such as trimethylene diisocyanate, tetramethylene 
diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 
1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-diisocyanate, 
and 1,3-butylene diisooyanate, and mixtures thereof; the 
aliphatic-aromatic diisocyanates such as 4,4'-diphenylene methane 
diisocyanate, 2,4- or 2,6-tolylene diisocyanate, and mixtures thereof, 
4,4'-toluidine diisocyanate, and 1,4-xylylene diisocyanate; the 
triisocyanates such as triphenylmethane-4,4',4"-triisocyanate, 
benzene-1,3,5-triisocyanate, and toluene-2,4,6-triisocyanate; and the 
tetraisocyanates such as 4,4'-diphenyldimethyl 
methane-2,2',5,5'-tetraisocyanate; the polymerized dimers and trimers, 
polymethylenepolyphenylene polyisocyanates having --N.dbd.C.dbd.0 
functionalities of 2 and 3 and the like. 
In addition, the organic polyisocyanates can be prepolymers derived from a 
polyol such as glycols (e.g ethylene glycol and propylene glycol), as well 
as other polyols such as glycerol, trimethylolpropane, hexanetriol, 
pentaerythritol, and the like, as well as monoethers, such as diethylene 
glycol, tripropylene glycol and the like and polyethers, i.e. alkylene 
oxides that may be condensed with these polyols to form polyethers are 
ethylene oxide, propylene oxide, styrene oxide and the like. These are 
generally called hydroxyl-terminated polyethers and can be linear or 
branched. Especially useful are those derived by reacting polyols such as 
ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butylene 
glycol, 1,3-butylene glycol, 1,6-hexanediol, and their mixtures, glycerol 
trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, 
sorbitol, methyl glucosides, sucrose and the like with alkylene oxides 
such as ethylene oxide, propylene oxide, their mixtures and the like. 
Preferred polyisocyanates useful as cross-linking agents in the practice of 
this invention include the reaction product of toluene diisocyanate and 
trimethylolpropane and the isocyanurate of hexamethylene diisocyanate. 
Any suitable aliphatic, cycloaliphatic, aromatic, alkyl monoalcohol or 
phenolic compound can be used as the blocking agent in the blocked 
polyisocyanate cross-linking agents. Examples include aliphatic alcohols 
such as methanol, ethanol, chloroethanol, propanol, butanol, pentanol, 
hexanol heptanol, octanol, nonanol, 3,3,5-trimethylhexanol, decanol, and 
lauryl alcohol; aralkyl alcohols such as phenylcarbinol, 
methylphenylcarbinol; ethylene glycol monomethyl ether, ethylene glycol 
monethyl ether, ethyleneglycol monopropyl ether, ethylene glycol monobutyl 
ether, and the like; phenolic compounds such as phenol and substituted 
phenols having substituents such as alkyl, alkoxy, halogen, nitro etc. 
which do not adversely affect the coating operation. Examples include 
cresol, nitrophenol, chlorophenol, and tert-butylphenol. A preferred 
blocking agent is ethylene glycol monopropyl ether. 
Additional blocking agents include tertiary hydroxyl amines such a 
diethylethanolamine, and oximes such as methyl ethyl ketoxime, acetone 
oxime, cyclohexanone oxime, and caprolactam. A preferred oxime is 
methyl-n-amyl ketoxime. 
The blocked polyisocyanates useful as cross-linking agents in the practice 
of this invention are formed by reacting sufficient quantities of blocking 
agent with the desired organic polyisocyanate under reaction conditions 
known in the art to produce a product devoid of free isocyanate groups 
when the reaction has run its course. Blocked polyisocyanates are 
generally known in the art and are described, for example, in U.S. Pat. 
Nos. 3,799,854; 3,984,299; 4,031,050; and 4,605,690, the disclosures of 
which are incorporated herein by reference. The preferred blocked organic 
polyisocyanate cross-linking agents useful in the practice of this 
invention are formed by the combination of an aliphatic polyol such as 
trimethylolpropane or pentaerythritol, a diisocyanate such as toluene 
diisocyanate, and a monoalcohol blocking group such as 2-ethylhexanol or 
ethylene glycol monopropyl ether. Such blocked polyisocyanates typically 
will deblock and react with the amino resins of this invention at 
temperatures of from about 125.degree. C. to about 190.degree. C. 
The poly(.beta.-hydroxy) esters or activated poly esters useable as 
cross-linking agents in the practice of this invention are generally known 
as transesterification agents. These materials are polyesters which have 
alkylene glycol, alkylene glycol monoether, alkylene glycol monoester, or 
similar moieties as the esterifying group. Upon heating, the glycol 
portion of the ester is lost and the resulting acid moiety reacts with 
amine or alcohol groups of the amine resin to effect cross-linking. 
Usually the polyester moiety of the .beta.-hydroxy or .beta.-activated 
esters will be a high molecular weight aliphatic polyacid. Examples 
generally are poly(2-hydroxyalkyl) esters of polycarboxylic acids. The 
polycarboxylic acids include, for example, azelaic acid, terephthalic 
acid, succinic acid, and aliphatic di- or tricarboxylic acids of 4 to 12 
carbon atoms. The alcohol portion of the esters include such alcohols as 
ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, and the 
like. These transesterification agents are known in the art; see, for 
example, U.S. Pat. Nos. 4,423,167; 4,423,169; 4,352,842; 4,362,847; 
4,397,990; 4,401,774; 4,405,662; 4,405,703; and 4,489,182, the disclosures 
of which are incorporated herein by reference. 
Pigment Grind Resins 
The pigment grind resin formulations employed in the electrodeposition 
compositions of the invention are typical and generally known in the art. 
The pigment usually comprises carbon black and other pigmenting agents, 
such as titantium dioxide, strontium dioxide, and other pigments necessary 
for the production of the desired color. The grind resins are amine 
derivatives of epoxy resins of appropriate molecular weight which will 
permit the grind resins to function both as surfactant-like compounds to 
wet and incorporate the pigments into the composition and as resinous 
materials which will combine with the cross-linking agents in the final 
deposited film. 
Typical grind resins useful in the practice of this invention include the 
quaternary ammonium salt grind resins generally disclosed in U.S. Pat. 
Nos. 3,925,180; 3,936,405; 3,962,165; 4,071,428; and 4,530,945; and the 
"castor oil" type of grind resins disclosed in U.S. Pat. No. 4,612,338, 
the disclosures of which are incorporated herein by reference. 
The procedures, parameters, and conditions for the preparation of the 
pigment grind resin formulations and the proportions and amounts of 
ingredients necessary are those typically known in the art. As is 
appropriate, dibutyl tin oxide is also incorporated into pigment grind 
resin formulation. This ingredient is important for promotion of the 
cross-linking reaction upon baking or curing. 
Electrodeposition Compositions 
The aqueous electrodeposition compositions are formed from the principal 
emulsions, the pigment grind resin formulations and water to provide a 
solid content of from about 10% to about 65% by weight. The ratio of 
weights of the pigment grind resin formulations and the principal resin 
emulsions are from about 1:10 to about 4:10. The pH of the 
electrodeposition compositions may be from about pH 2 to about pH 8.5, and 
the ratio by weight of the amine resins to cross-linking agents in the 
electrodeposition compositions may be from about 2:3 to about 5:1. 
Likewise, the ratio of the pigment to pigment grind resins is from about 
2:1 to about 6:1. 
Generally, the principal resin emulsions and pigment grind resin 
formulations are combined to form the electrodeposition compositions 
shortly before use in the electrodeposition baths. The electrodeposition 
compositions may be further diluted with water and other components such 
as coalescing agents, anti-cratering agents, film build agents, 
surfactants, anti-pitting agents and the like to produce the 
electrodeposition baths. Sufficient quantities of the principal resin 
emulsions and pigment grind resin formulations are used so that the 
coating produced on the substrate will have sufficient thickness so as to 
provide such desired characteristics as a smooth surface, high film build 
and be effective in a low temperature curing step. In addition, the bath 
proportions of components should enable short coating time at a low 
temperature. 
Electrodeposition Process 
The electrodeposition process typically takes place in an electrically 
insulated tank containing an electrically conductive anode which is 
attached to a direct current source. The size of the tank will depend upon 
the size of the substrate article to be coated. Typically, the tank will 
be constructed of stainless steel or mild steel lined with a dielectric 
coating such as epoxy-impregnated fiberglass or polypropylene. The typical 
size of the electrodeposition tank for such articles as automobile or 
truck bodies will be designed to contain from about 240,000 liters to 
about 500,000 liters of electrodeposition bath. 
Adjustment of the electrodeposition parameters such as voltage, time, bath 
temperature, percent solids content of the electrodeposition bath, pH of 
the bath, and the like will promote the deposition of a film having the 
desired characteristics. Typically, immersion for a period of about 1 to 4 
minutes at a temperature of between about 80.degree.-100.degree. C. and at 
a DC voltage of from about 100 volts to about 500 volts in a bath having a 
solids content of from about 18% to about 30% provides smooth, durable, 
corrosion resistant films on the substrate article of a thickness of about 
1.2 mils (0.0031 cm). Preferred values for these electrodeposition 
parameters are about 2 minutes immersion, 200-350 volts, 90.degree. F. 
(32.degree. C.), and 20% solids content. 
After the film has been deposited in the substrate by the electrodeposition 
process, the film-coated article is removed from the dip tank and the 
excess bath solids are rinsed off. The film-coated substrate article is 
then passed through an oven where the film is cured an hardened. In 
general, the film-coated substrate bodies are heated to a temperature of 
from about 300.degree. F. (149.degree. C.) to about 400.degree. F. 
(204.degree. C.), preferably at from about 325.degree. F. (163.degree. C.) 
to about 350.degree. F. (177.degree. C.), for a period of from about 20 to 
25 minutes to effect the hardening or cross-linking reaction in the film. 
During this process, the film viscosity of the resin systems decreases at 
the oven temperatures and the films of this invention flow so as to 
provide uniform coverage of the substrate body. As the cross-linking 
reaction proceeds, film flow ceases and the film begins to harden to 
produce the final cured film adhering to the substrate body. The hardened 
coating thicknesses produced in accordance with this invention lie in the 
range of from about 16 microns to about 36 microns. 
The following examples are provided to enable one skilled in the art to 
practice the present invention. These examples are merely illustrative of 
the invention and are not to be read as limiting the scope of the 
invention as defined by the appended claims.

EXAMPLE 1 
Principal Resin 
A 3-liter, 3-necked flask was flushed with dry nitrogen and then charged 
with 250 g of a carboxyl-terminated polybutadiene/acrylonitrile random 
copolymer (CTBN) which had been end-capped by prior reaction with the 
diglycidyl ether of bisphenol A (WPE=344; available as WC-8006, Wilmington 
Chemicals). To this material was added 80 g of the diglycidyl ether of 
bisphenol A (WPE=186), 220 g of bisphenol A, and 93 g of toluene. 
The mixture was reacted under conditions detailed above under the heading 
"General Synthetic Method for Preparing the Principal Resin". When the WPE 
of the reaction product had reached 1750, the mixture was cooled to room 
temperature. The final resin had a polybutadiene/acrylonitrile B block 
content of about 10%. 
EXAMPLE 2 
Principal Resin 
Using the procedure of Example 1, the following materials were reacted to 
produce a principal resin having a polybutadiene/acrylonitrile B block 
content of about 15% and a final WPE of about 1800: 
375 g of WC-8006 Epoxy-capped, carboxyl-terminated 
polybutadiene/acrylonitrile random copolymer having a WPE of 344; 
420 g of 2,2-bis-[p-(3-Butoxy-2-glycidyloxypropyloxy)phenyl]propane 
(WPE=334); 
205 g of Bisphenol A; 
90 g of toluene. 
EXAMPLE 3 
Principal Resin 
Using the procedure of Example 1, the following materials were reacted to 
produce a principal resin having a polybutadiene/acrylonitrile B block 
content of about 15% and a final WPE of about 1250: 
375 g of WC-8006 Epoxy-capped, carboxyl-terminated 
polybutadiene/acrylonitrile random copolymer having a WPE of 347.5; 
187.5 g of the diglycidyl ether of bisphenol A 
255 g of Bisphenol A; 
87 g of toluene. 
EXAMPLE 4 
Principal Resin 
Using the procedure of Example 1, the following materials were reacted to 
produce a principal resin having a polybutadiene/acrylonitrile B block 
content of about 15% and a final WPE of about 1200: 
375 g of WC-8006 Epoxy-capped, carboxyl-terminated 
polybutadiene/acrylonitrile random copolymer having a WPE of 347.5; 
187.5 g of the diglycidyl ether of resorcinol (WPE=125; available as WC-69 
from Wilmington Chemicals); 
125 g of Hydroquinone; 
85 g of toluene. 
EXAMPLE 5 
Amine Resin 
The principal resin prepared in Example 1 was mixed with 63 g of 
N-methylethanolamine and the temperature of the resulting exothermic 
reaction was kept below about 115.degree. C. with cooling. When the 
exothermic reaction had subsided, the mixture was heated for an additional 
one hour at a temperature of about 100.degree.-110.degree. C. At the end 
of this time, the mixture was cooled and 335 g of methyl iso-butyl ketone 
was added and the product is removed from the reaction vessel and allowed 
to cool to room temperature. 
EXAMPLE 6 
Amine Resin 
Using the procedure of Example 5, the principal resin of Example 2 was 
converted to an amine resin by reaction with 412 g of 
N-methylethanolamine. The final product was taken up in 335 g of methyl 
iso-butyl ketone. 
Example 7 
Amine Resin 
Using the procedure of Example 5, the principal resin of Example 3 was 
converted to an amine resin by reaction with 61 g of N-methylethanolamine. 
The final product was taken up in 300 g of methyl iso-butyl ketone. 
EXAMPLE 8 
Amine Resin 
Using the procedure of Example 5, the principal resin of Example 4 was 
converted to an amine resin by reaction with 63 g of N-methylethanolamine. 
The final product was taken up in 350 g of methyl iso-butyl ketone. 
EXAMPLE 9 
Blocked Diisocyanate Cross-Linking Agent 
The primary cross-linking agent was prepared by slowly charging 870 parts 
of trimethylolpropane into a suitable reactor vessel containing 3387 parts 
of an 80/20 isomer mixture of 2,4- and 2,6-toluene diisocyanate, 1469 
parts of methyl iso-butyl ketone, and 2 parts of dibutyl tin dilaurate 
under agitation with a nitrogen blanket. The reaction mixture was 
maintained at a temperature below about 110.degree. F. (43.degree. C.). 
The charge was held an additional one and one-half hours at 110.degree. F. 
(43.degree. C.) and then heated to 140.degree. F. (60.degree. C.) at which 
time 2026 parts of ethylene glycol monopropyl ether was added. The charge 
was maintained at 210.degree. F. (99.degree. C.) to 220.degree. F. 
(104.degree. C.) for one and one-half hours until analysis by infrared 
spectroscopy indicated the absence of --N.dbd.C.dbd.O functionality. The 
batch was then diluted by the addition of 2116 parts of methyl iso-butyl 
ketone. 
EXAMPLE 10 
Blocked Diisocyanate Cross-Linking Agent 
An 80/20 mixture of 2,4- and 2,6-toluene diisocyanate (2949 parts) was 
charged to a suitable reaction vessel under a dry nitrogen atmosphere. 
2-Ethylhexanol (2209.4 parts) was added to the vessel with agitation at 
such a rate to keep the reaction mixture at a temperature below about 
120.degree. F. (49.degree. C.). After addition was complete, the mixture 
was stirred at this temperature until an isocyanate equivalent weight of 
285-325 was obtained (about thirty minutes). Dibutyl tin dilaurate (0.9 
parts) was added to the reaction vessel contents and the mixture was 
heated to 150.degree. F. (66.degree. C.). Trimethylolpropane (264.7 parts) 
was added at a suitable rate to keep the temperature of the reaction 
mixture below about 250.degree. F. (121.degree. C.). After addition was 
complete, the mixture was heated at 250.degree. F. (121.degree. C.) for an 
additional one and one-half hours. At the end of this time, the mixture 
was cooled and diluted by the addition of 2282.4 parts of methyl iso-butyl 
ketone and 253.6 parts of n-butanol. 
EXAMPLES 11 
Castor Oil Grind Resin 
The pigment grind vehicle was prepared by additing the following components 
to a suitable reactor vessel: 2280 parts of Iris (glycidyl ether) of 
castor oil EpiRez.RTM. 505 (WPE=600), manufactured by Celanese Corp., 
Louisville, Ky., and a mixture of 331 parts of ethylene glycol monobutyl 
ether and 619 parts of polyglycolamine H-163. This mixture was heated at 
77.degree. C. for one and one-half hours. The mixture was heated to 
115.degree. C. for an additional one hour and then cooled to room 
temperature. 
EXAMPLES 12 
Pigment Paste 
A pigment paste was prepared by grinding at ambient temperature 123 parts 
of the pigment grind resin of Example 11, 8 parts of glacial acetic acid, 
252 parts of deionized water, 4 parts of dibutyl tin dioxide, 17 parts of 
carbon black, 56 parts of lead silicate, and 145 parts of clay in a 
suitable mill for about one-half hour until the average particle size was 
determined to be less than about 12 microns. 
EXAMPLE 13 
Grind Vehicle 
A. Ethylene glycol monopropyl ether (52 parts) and toluene diisocyanate (87 
parts) were charged to a reaction vessel under a dry nitrogen blanket and 
stirred at a temperature of below about 100.degree. F. (38.degree. C.) for 
a period of one and one-half hours. 
B. In a suitable reactor vessel, 455 parts of an alkylaryl polyether 
alcohol (Triton.RTM. X-102, manufactured by Rohm & Haas, Philadelphia, 
Pa.) and 51 parts of methyl iso-butyl ketone (previously azeotroped to 
remove water), were added to 109 parts of 2,4-toluene diisocyanate. The 
resulting reaction mixture was maintained at 115.degree. F. (46.degree. 
C.) for two hours. At the end of this time, 56 g of N,N-dimethyl 
ethanolamine were added to the reaction mixture, and the resulting mixture 
was heated at 160.degree. F. (71.degree. C.) for one hour. Finally, 50 
parts of ethylene glycol monobutyl ether, 75 parts of lactic acid, and 89 
parts of deionized water were added, and the reaction mixture held at 
190.degree. F. (88.degree. C.) for one hour. 
C. The grinding vehicle was prepared by charging 88 parts of the adduct 
from step A to a reaction vessel containing 206 parts of diepoxy adduct of 
bisphenol A and its bis-glycidyl ether, EPON.RTM. 1002F (WPE=650, 
manufactured by Shell Chemical Co., Houston, Tex.) and 39 parts of methyl 
iso-butyl ketone. The reaction temperature was maintained at 250.degree. 
F. (121.degree. C.) for one hour. Ethylene glycol monobutyl ether (186 
parts) and the adduct from step B (381 parts) were added. The resulting 
mixture was maintained at 180.degree. F. (82.degree. C.) for four hours, 
and then cooled for use. 
EXAMPLE 14 
Pigment Paste 
A pigment paste was prepared by grinding 1081.1 parts of the grind vehicle 
from Example 13, 2,208.5 parts of deionized water, 1,947.4 parts of clay, 
272 parts of carbon black, 341.4 parts of lead silicate, and 77.6 parts of 
dibutyl tin dioxide in a steel ball mill for 15 minutes. Strontium 
chromate (172.4 parts) was blended into the mill and the resulting mixture 
was ground for twenty-four hours, after which time the average particle 
size was determined to be 16 microns. An additional portion of 324.8 parts 
of the grind vehicle from the previous Example was added, together with 
116.8 parts of deionized water and the resulting mixture was ground for an 
additional three hours. 
EXAMPLES 15-18 
Principal Emulsions 
The amine resins of Examples 5-8 were used to make principal emulsions of 
Example 15-18. In each case, the amine resin (550 g non-volatile resin 
content) was mixed with 350 g of the cross-linking agent of Example 9. 
Acetic acid (80 g, 25% aqueous solution) was added and the resulting 
mixture stirred for fifteen minutes. Water (600 g) was slowly added to the 
mixture with vigorous stirring. The resulting mixture is sheared for 60 
minutes and then 800 g of water are added with mild stirring. The final 
emulsions contained about 36% by weight resin solids. These emulsions were 
used to prepare electrocoat bath compositions. 
EXAMPLES 19-22 
Electrocoat Baths 
The principal emulsions prepared as detailed in Examples 15-18 were used to 
make electrocoat bath compositions. In each case emulsion, containing 
577.5 g of non-volatile resin content, was further diluted with 1000 g of 
water and the pigment paste of Example 14 (222.5 g non-volatile solids 
content) was slowly stirred in. The resulting baths were further diluted 
with about 1000 g of water to produce final electrocoat baths having a 
solids content of about 20% by weight. 
EXAMPLES 23-26 
Electrocoating Procedures 
Steel panels of 12 inches (30.5 cm).times.4 inches (10.2 cm) dimensions 
were electrocoated using, separately, each of the coating baths of 
Examples 19-22 under the following conditions: 
______________________________________ 
Bath temperature 80-100.degree. C. 
Current 1 Ampere 
Voltage 300 volts 
Immersion time Minutes 
______________________________________ 
The coated panels were cured at a temperature of 325.degree. F. 
(163.degree. C.) for 25 minutes to produce final film thicknesses on the 
steel panels of about 1.2 mil (0.0031 cm). 
EXAMPLES 27 
Corrosion Tests 
The corrosion resistance of electrocoat films of the present invention were 
compared in two separate tests with those of two prior art electrocoat 
films which did not contain the polybutadiene or 
polybutadiene/acrylonitrile B blocks. Corrosion resistance was measured 
using the General Motors "Scribe Creep" test. In this test, coated steel 
panels are scratched using an awl and then subjected to several cycles of 
immersion in a salt-water bath, exposure to heat, cold, and humidity. The 
surface paint layer which has been loosened from the panel surface by 
corrosion is removed, and the lateral width of the corrosion about the 
scribe por scratch line is measured at several points along the scratch. 
The average width of this "creep" of the corrosion away from the scratch 
line is reported as the "scribe creep" for the particular coating. The 
results of these tests are given in Tables 3 and 4. 
TABLE 3 
______________________________________ 
Corrosion Test 1 
Average Scribe Creep (mm) 
Coating Made From 
Prior Art 
Prior Art 
Resin of Example 
Substrate Coating 1 
Coating 2 
1 2 3 4 
______________________________________ 
Bare, cold-rolled steel 
6.50 -- 4.60 4.17 -- -- 
Phosphated, cold- 
1.54 -- 1.22 13.6 -- -- 
rolled steel 
Phosphated, hot- 
0.82 -- 1.02 0.94 -- -- 
dipped steel 
______________________________________ 
TABLE 4 
______________________________________ 
Corrosion Test 2 
Average Scribe Creep (mm) 
Coating Made from 
Prior Art 
Prior Art 
Resin of Example 
Substrate Coating 1 
Coating 2 
1 2 3 4 
______________________________________ 
Bare, cold-rolled 
8.29 9.40 -- 5.65 6.21 5.88 
steel 
Phosphated, cold- 
6.93 7.04 -- 5.68 5.76 5.62 
rolled steel 
(phosphate coating 
1) 
Phosphated, cold- 
6.88 4.49 -- 5.88 5.28 4.66 
rolled steel 
(phosphate coating 
2) 
Hot-dipped, 2.10 2.83 -- 2.62 1.80 1.79 
galvinized steel 
Phosphated, hot- 
1.62 2/30 -- 1.76 1.89 1.86 
dipped galvanized 
steel 
______________________________________ 
Examination of the data presented in Tables 3 and 4 show that the corrosion 
resistance data for films formed of the compositions of the present 
invention match or exceed that of typical prior art electrocoat films. The 
effects are most pronounced for cold-rolled steel and phosphated 
cold-rolled steel. 
EXAMPLE 28 
Reverse Impact Tests 
Panels coated with two typical prior art electrocoat films and coated with 
films formed in accordance with the teachings of this invention were 
subjected to reverse impact tests using ASTM D-2794-84, "Standard Test 
Method for Resistance of Organic Coatings to the Effects of RApid 
Deformation (Impact)." In this test, a weight is dropped against a rod 
which has a ball-shaped rounded end which rests against a coated steel 
panel. The impact deforms the panel, and the adherence of the film coating 
to the side opposite impact is observed. 
In these tests, the Prior Art Coating 1 failed to adhere at an impact of 
about 40 ft-lb, while Prior Art Coating 2 failed at about 140-150 ft-lb. 
The coatings prepared in accordance with this invention did not fail at 
the limit of the testing device, 160 ft-lb. 
EXAMPLE 29 
Mandrel-Bend Tests 
Panels coated with two typical prior art electrocoat films and coated with 
films formed in accordance with the teachings of this invention were 
subjected to a conical mandrel bend test, ASTM D-522-60, "Elongation of 
Attached Organic Coatings with Conical Mandrel Apparatus." In this test, 
film-coated panels are bent over a conically shaped mandrel so that the 
panel and film are subjected to a sharp radius of bending at one end of 
the mandrel and bending at increasing radii along the mandrel. The damage 
to the film, if any, is greatest at the small radius bend. The length of 
delaminated film from the side of the coated panel having the small radius 
bend is measured. In this test, panels coated with Prior Art Coating 1 had 
an average length of delamination of 5 mm, Prior Art Coating 2, 12 mm, and 
the films made in accordance with the teachings of this invention 
exhibited no delamination.