Thermosetting resinous binder compositions and their use as coating materials

A thermosetting resinous binder composition, heat-curable in combination with a transesterification-promoting metal compound as a catalyst to provide an insoluble infusible coating, comprising a mixture of: PA1 (1) a non-acidic resinous compound essentially free of ethylenical unsaturation, having a molecular weight of at least 900 and a hydroxyl content of at least 0.2 equivalent per 100 g, and PA1 (2) as cross-linking agent a non-acidic polyester of a polycarboxylic acid having more than one beta-hydroxyl ester group molecule, at least one of components (1) and (2) having a hydroxyl or beta-hydroxyl ester functionality, respectively, of more than 2, characterized in that the beta-hydroxyl ester group is substituted in the gamma-position by a hydroxyl, amino and/or transferable ester group derived from a polycarboxylic

FIELD OF THE INVENTION 
The invention relates to novel thermosetting resinous binder compositions 
which can be cured by a transesterification mechanism. The invention 
further relates to the use of coatings, in particular in water-borne 
paints, such as for cathodic electrodeposition paints. 
BACKGROUND OF THE INVENTION 
Thermosetting coating compositions usually contain a hydroxyl or 
epoxy-containing component and a cross-linking component; curing catalysts 
are often added to reduce curing time and/or temperature. Curing times of 
up to 1/2 hour and curing temperatures of up to 200.degree. C. are for 
many purposes acceptable in the thermosetting coating field. 
The cross-linking component reacts during stoving with hydroxyl and/or 
epoxy groups of the main binder component, and the cross-linking provides 
a coating which is insoluble and infusible, and therefore resistant to 
solvents and elevated temperatures. 
Another type of coating materials contains an air-drying binder, which can 
cross-link through carbon-carbon double bonds, in contact with oxygen; 
drying accelerators are here some metal compounds, such as Co- and 
Mn-naphthenate. 
U.S. Pat. No. 4,332,711, issued June 1, 1982 discloses a thermosetting 
binder composition comprising: 
(I) a mixture or precondensate of 
(1) a non-acidic resinous compound essentially free of ethylenical 
unsaturation, having a molecular weight of at least 900 and a hydroxyl 
content of at least 0.2 equivalents per 100 g, and 
(2) as cross-linking agent a non-acidic polyester of a polycarboxylic acid, 
having more than one beta-hydroxyl ester group per molecule, at least one 
of components (1) and (2) having a hydroxyl functionality of more than 2, 
and 
(II) as curing catalyst a transesterification-promoting metal salt or metal 
complex which is soluble in liquid hydro carbons. 
U.S. patent application Ser. No. 255,196, filed Apr. 20, 1981, now U.S. 
Pat. No. 4,362,847, issued Dec. 7, 1982, describes similar compositions, 
in which the transesterification-promoting metal compound (II) is 
insoluble in liquid hydrocarbons. 
Such curing systems operate by transesterification of the ester groups of 
the cross-linking agent with hydroxyl groups of the resinous compound, 
with elimination of a glycol. 
According to the prior applications, the glycol part of component (I) (2) 
may have substituents such as alkyl-, ether- or stable ester groups, such 
as those derived from branched mono-carboxylic acids. It has been 
demonstrated that this ester group does not generally react. 
SUMMARY OF THE INVENTION 
The present invention provides an improvement of prior art compositions in 
that the cross-linking component has further active groups with respect to 
the ester group in the gamma-position, such as hydroxyl, amino and/or 
transferable ester groups derived from polycarboxylic acids. Incorporation 
of such groups may provide various advantages in the curing step, such as 
better cure at lower temperature, removal of amino nitrogen, reduced 
weight loss, and better appearance. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention can therefore be defined as a thermosetting resinous 
binder composition, heat-curable in combination with a 
transesterification-promotion metal compound as a catalyst to provide an 
insoluble infusible coating, comprising a mixture of: 
(1) a non-acidic resinous compound essentially free of ethylenical 
unsaturation, having a molecular weight of at least 900 and a hydroxyl 
content of at least 0.2 equivalent per 100 g, and 
(2) as cross-linking agent a non-acidic polyester of a polycarboxylic acid 
having more than one beta-hydroxyl ester group per molecule, at least one 
of components (1) and (2) having a hydroxyl or beta-hydroxyl ester 
functionality, respectively, of more than 2, 
characterized in that the beta-hydroxyl ester group is substituted in the 
gamma-position by a hydroxyl, amino and/or transferable ester group 
derived from a polycarboxylic acid. 
In this context some general expressions are defined and explained as 
follows: 
Non-acidic means that the material has an acid value of not more than 0.18 
meq/g (acid number not more than 10). This will allow a residual acid 
content which in some cases is inevitable in praxis due to the method of 
preparation. Preferably, the acid content is not more than 0.1 meq/g, and 
for systems intended for cathodic electrodeposition the acid content is 
preferably not more than 0.02 meq/g; all values are based on solid 
material. 
Hydroxyl means aliphatic or cycloaliphatic hydroxyl, not phenolic hydroxyl. 
Beta-hydroxyl ester in the definition of component (2) means that the 
carbon atom adjacent to the esterified hydroxyl group has a free hydroxyl 
group. According to the invention the component (2) has now further 
reactive groups in the gamma-position. 
Component (1) has a hydroxyl content of at least 0.2 equivalent, and 
preferably not more than 0.8 equivalent per 100 g. Component (1) should be 
a soluble, fusible compound. Component (1) may be chosen from several 
classes of hydroxyl-containing materials, such as alkyd resins, epoxy 
resins, including the linear polymeric type derivatives of bisphenol A and 
epichlorohydrin, esters of epoxy resins, amine adducts of epoxy resins, 
and polymers prepared by the polymerization or copolymerization of 
ethylenically unsaturated monomers. 
A preferred type of alkyd resin is an alkyd resin prepared from a 
polycarboxylic acid or anhydride thereof, a polyhydric alcohol, and 
glycidyl esters of branched monocarboxylic acids. 
Another preferred component (1) is an epoxy resin or derivative thereof. 
Preferred epoxy resins are glycidyl ethers of 
2,2-bis(4-hydroxyphenyl)propane having the general formula: 
##STR1## 
wherein R is the group: 
##STR2## 
and r is a number which for epoxy resins of different molecular weight can 
differ. For making soluble derivatives preference is given to liquid or 
semi-liquid epoxy resins (wherein r has a value of from 0 to 1) or to the 
lower solid epoxy resins wherein r has a value of up to 4; epoxy resins 
which are suitable without modification have a molecular weight of more 
than 1400, and r has a value of more than 4. In the solid resins of the 
latter type a great part of the terminal glycidyl groups is usually 
present in hydrolyzed form as glyceryl groups, due to the methods of 
preparation. 
Suitable epoxy resins of this type have molecular weights from 2000 to 
4000, epoxy equivalent weights of the same order, and have from 0.35 to 
0.40 hydroxyl equivalents per 100 g; the epoxy content is too low to 
effect sufficient cross-linking without a cross-linking agent. 
Another suitable polyether of the latter type is a high-molecular weight 
linear polyhydroxyl ether, having a molecular weight of more than 20,000 
and containing 0.35 hydroxyl equivalents per 100 g. Molecular weights 
herein are average molecular weights (Mn) as usual in polymeric compounds. 
Suitable derivatives of epoxy resins are hydroxyl-containing esters, such 
as esters obtained by esterification of one or both epoxy groups of the 
lower epoxy resins (wherein r in the above formula has a value of from 0 
to 4) with a monocarboxylic acid, preferably a hydroxyalkane 
monocarboxylic acid, such a glycolic acid, lactic acid or preferably 
dimethylol propionic acid. Such esterifications are preferably carried out 
at temperatures below 150.degree. C. to avoid esterification of hydroxyl 
groups, in the presence of catalysts known to accelerate epoxycarboxyl 
addition reactions, such as tertiary amines, quaternary ammonium salts, 
quaternary phosphonium salts or stannous octoate. 
Other suitable epoxy resin derivatives are soluble adducts with primary or 
secondary amines, in particular amines having one or more hydroxyalkyl 
groups, such as diethanolamine. The epoxy resin here is preferably one of 
the above formula, wherein r is from 3 to 4. 
Other suitable epoxy resin/amine adducts, in particular suitable for 
cathodic electrodeposition, will be described hereinafter. 
Further suitable compounds to act as component (1) are polymeric reaction 
products of caprolactone with polyhydric alcohols, and resinous polyols 
prepared by copolymerization of styrene with allyl alcohol. 
Still further suitable compounds to act as component (1) are copolymers of 
hydroxyalkyl acrylates and methacrylates with other copolymerizable 
ethylenically unsaturated compounds, such as styrene, methyl methacrylate, 
butyl acrylate, and vinyl esters, in particular vinyl esters of branched 
monocarboxylic acids. Copolymers containing the residues of the latter 
component can be made according to the process described in British Pat. 
No. 1,418,372. 
The compounds outlined above are in particular suitable for thermosetting 
compositions to be applied as solutions in organic solvents. Compounds 
which are solid at room temperature and have softening points above 
70.degree. C. can also be used in thermosetting powder compositions. 
For water-borne paints, in particular suitable for cathodic 
electrodeposition, a further group of compounds has been found very useful 
as component (1). 
Cathodic electrodeposition for applying a resinous coating to metals is 
known in the art. The binder is usually prepared by reacting a diglycidyl 
ether of a dihydric phenol, such as 2,2-bis(4-hydroxyphenyl)propane with 
secondary and/or primary amines; the amine adduct can be protonized with 
an acid, to make it water-soluble, and to provide the electrical charge 
for transport to the cathode. Suitable primary amines are 
monoalkanolamines, for example, monoethanolamine and 
mono-isopropanolamine. Very suitable is 3-(N,N-dimethylamino)propylamine. 
Suitable mono-secondary amines are dialkanolamines, for example, 
diethanolamine, and di-isopropanolamine. A very suitable di-secondary 
amine is an addition product of 1 mole of 1,6-diaminohexane with 2 moles 
of glycidyl esters of branched monocarboxylic acids. The reaction of the 
amines with the diglycidyl ethers can be carried out in one or more steps; 
thus a mono-secondary amine may be reacted first with the diglycidyl 
ether, and a primary amine and/or a di-secondary amine can then be added. 
Component (2) has more than one beta-hydroxyl ester group per molecule for 
sufficient cross-linking at acceptable curing temperature within 
acceptable time, for example at temperatures up to 200.degree. C. and 
curing times of up to 30 minutes. 
According to the invention the beta-hydroxyl ester group is substituted in 
the gamma-position by a hydroxyl, amino and/or transferable ester group 
derived from polycarboxylic acid. Transferable in this connection means 
that such an ester group may be transesterified under curing conditions. 
Although the invention relates to such esters of polycarboxylic acids in 
general, it is of particular advantage for esters of dicarboxylic acids, 
as compared with the beta-hydroxyalkyl esters which do not have such a 
gamma-substituent and are similarly derived from a dicarboxylic acid. 
Components (2) having a gamma-hydroxyl group can be prepared by 
esterification of a polycarboxylic acid with glycidol or glycerol. Such 
cross-linking components provide in general a better cure at lower 
temperature. Suitable dicarboxylic acids are, for example, adipic acid, 
azelaic acid, terephthalic acid, isophthalic acid, and dimerized 
unsaturated fatty acids. Glycidol may be reacted in a molar ratio of 2:1 
or slightly more, at moderate temperatures, for example 
110.degree.-150.degree. C., to form essentially monomeric 
beta-gamma-dihydroxy-propyl esters. 
Glycerol may be reacted with dicarboxylic acids at higher temperatures, for 
example 180.degree.-250.degree. C., with elimination of the water formed 
until essentially all acidity is eliminated. The product is in general a 
polyester having the general formula: 
##STR3## 
wherein n may have an average value of from 0 to 30, depending on the 
molar ratio glycerol/dicarboxylic acid, and R is the hydrocarbon residue 
of the dicarboxylic acid. Such polyesters, with n being 1 or higher, have 
in the main chain one or more transferable beta-hydroxy alkyl ester groups 
derived from a polycarboxylic acid, and have in general two terminal 
beta-gamma-dihydroxy alkyl groups. The formation is attributed to the 
greater reactivity of the primary hydroxyl group. 
For preparing an ester wherein n=0, a large excess of glycerol has to be 
used, and if such a polyester is required, it can better be prepared by 
reaction of the dicarboxylic acid with glycidol, as described 
hereinbefore. For the esterification with glycerol, the reaction time can 
sometimes be reduced considerably by addition, at a certain acid value, of 
the calculated amount of a mono- or diepoxide, such as glycidol or a 
diglycidyl ester. As the reaction of carboxyl with epoxide is faster than 
the normal esterification reaction, the saving of time may be 
considerable. 
In reacting the dicarboxylic acid with glycidol or glycerol, catalysts may 
be added, such as dibutyl tin compounds or organic chromium compounds. 
Components (2) having transferable beta-hydroxyalkyl ester groups in the 
main chain can also be prepared by reacting a dicarboxylic acid with 
diglycidyl ester of a dicarboxylic acid, preferably in a glycidyl/carboxyl 
ratio of at least 1:1. Terminal groups in the polyester so produced will 
be glycidyl groups or beta-gamma-dihydroxyalkyl groups, the latter when 
part of the glycidyl groups has been hydrolyzed, for example due to the 
method of preparation of the glycidyl ester. Reaction of glycidyl ester 
and carboxylic acid can be performed at temperatures from 100.degree. to 
180.degree. C., preferably in the presence of a catalyst, for example a 
tertiary amine. Dicarboxylic acid and glycidyl compound or glycerol are 
reacted until an acid content of not more than 0.18 meq/g solids indicates 
that esterification is essentially complete. This is usually accomplished 
with 10 hours. When the acidity remains more than 0.25 meq/g the reaction 
may be completed by further addition of glycidyl compound in a small 
amount. 
The compounds having transferable ester groups in the main chain have two 
ester groups available for transesterification per mol of triol (glycerol) 
which evaporates and this may reduce the weight loss on cure considerably. 
A further advantage of such polyesters is that they have a higher 
viscosity than monomeric diester. This may contribute to a higher throwing 
power and a better appearance, such as less cratering and less pinholing. 
Further, a reduced sensitivity to hydrolysis may contribute to a better 
stability of aqueous paints. 
The beta-hydroxyalkyl ester groups of component (2) may further be 
substituted in the gamma-position by an amino group, preferably a 
dialkylamino group, such as a dimethyl- or diethylamino group. Such 
cross-linkers are of particular interest for cathodic electrodeposition, 
in particular when the gamma-substituent is a dialkylamino group. 
Cathodic electrodeposition requires sufficient protonization of amino 
groups by at least partial neutralization with an acid, and this 
protonization is promoted by the basic strength of the amino groups. To 
this end, strongly basic amino groups, such as dimethyl- or diethylamino 
groups are sometimes built into component (1), for example by reacting a 
polyepoxide with an amine mixture, which contains 
3-(N,N-dimethylamino)propylamine. Such strongly basic amino groups remain 
in the cured coating, and may reduce desirable properties such as salt 
spray resistance. 
According to one aspect of the invention such lower dialkylaminio groups 
are incorporated in component (2), in gamma-position with regard to the 
ester groups, for example by reaction of dimethylamine or diethylamine 
with a polyglycidyl ester of a polycarboxylic acid produced is easy to 
protonize for cathodic electrodeposition, and upon cure the gamma-amino 
alkane diol produced by transesterification evaporates. The remaining 
cured coating does not contain those strongly basic amino groups, and has 
an improved resistance to chemicals such as salt spray. 
The transesterification-promoting metal compound is preferably a metal salt 
or complex that is soluble in liquid hydrocarbons, such as white spirit or 
xylene. A commercially available concentrated solution in such a solvent 
can then easily be homogeneously diluted with a part of one of the other 
binder components, to provide a master batch containing the accelerator. 
In view of the small amounts of accelerator needed in the final binder 
composition this technique is recommendable. Suitable salts meeting that 
requirement are in general 2-ethyl hexoates (octoates) and naphthenates. 
Further, when these metal salts or complexes are insoluble or 
substantially insoluble in water, potential adverse effects by leaching 
out of accelerator into the aqueous phase of the aqueous suspensions are 
avoided. 
Very suitable in view of their generally high activity are, for example, 
salts (octoates or naphthenates) of lead, zinc, calcium, barium and 
iron(III). A suitable example of a metal complex is titanium acetyl 
acetonate. Other suitable salts, although in general less active than 
those mentioned above, are salts of tin(II), manganese, cobalt and 
dibutyltin, for example dibutyltin dilaurate. Further, metal salts that 
can be mentioned in general are octoates and naphthenates of the alkali 
and earth alkali metals, of the lanthanides, and of zirconium, cadmium, 
chromium, and acetyl acetonate complexes of lead, zinc, cadmium, cerium, 
thorium and copper. 
Mixtures of such salts and/or complexes can also be used. Some of the salts 
or complexes mentioned above are known as esterification and 
transesterification catalysts for the preparation of alkyd resins, epoxy 
resin esters, and linear polyesters for fibers, in general for the 
preparation of fusible polyesters which are soluble in organic solvents. 
However, the temperatures used there are generally far above 200.degree. 
C., the reaction times at least some hours, and the amount of catalyst is 
usually very low, below 0.1% by weight of the polyester. None of these 
uses indicated that these salts could be used as cross-linking 
accelerators in coatings, i.e. for the formation of insoluble, infusible 
polyester-like coatings, as in the present binder compositions. 
In the present compositions these accelerating salts or complexes can be 
used in amounts of 0.1-6, preferably 1-6 percent of the combined weights 
of components (1) and (2). In view of the varying metal content of 
available metal salts or complexes or solutions thereof the amount of 
catalyst is more conveniently indicated by the metal content in the 
compositions; metal contents of 0.3 to 2.0 percent by weight are suitable 
in general, and metal contents of 0.5-1.8 percent by weight are preferred. 
Other transesterification-promoting metal compounds that can be used in the 
present compositions are certain metal salts and oxides that are insoluble 
in liquid hydrocarbons, but may be soluble in other solvents such as 
water, alcohols, ethers, ketones, and esters, or mixtures thereof. 
Insoluble in liquid hydrocarbons can be defined more precisely in that the 
solubility in toluene at 20.degree. C. should not be more then 0.02 
percent by weight. These metal compounds are usually solids at room 
temperature, and may be used in finely divided form and/or in solution. 
Examples are the pigments lead silicate, red lead (Pb.sub.3 O.sub.4), lead 
oxide (PbO), zinc chromate, zinc tetraoxydichromate, and lead silico 
chromate, the oxide antomony trioxide, and the acetates, formiates and 
carbonates of Pb, Zn, Fe, Li, Cd and Bi. The quantity of the pigments 
needed is sometimes such as to exclude their use when the pigmentation 
they will provide (e.g., white, yellow or red) is not desired. On the 
other hand, such pigments may be desirable for improvement of corrosion 
resistance, for example in primers. These pigments may sometimes provide 
the desired transesterification activity in pigment/binder weight ratios 
from 0.02:1 upwards, more preferably from 0.1;1 upwards. Water-soluble 
salts, sometimes in the form of hydrates or aqueous solutions, may be 
desirable in aqueous coating compositions. Metal salts as mentioned above 
may be used in amounts of 1-8, preferably 3-8 percent by weight of the 
binder. Complex-forming agents may be added to improve the activity of 
some of these metal compounds, in particular those of zinc, upon cure, 
and/or to improve surface properties of a cured coating. Examples are 
acetyl acetic esters, acetyl acetone, 8-hydroxy quinoline. For example, 
zinc oxide (inactive in the gelation test) may show slight activity in an 
electrodeposition test; activity and surface appearance may then be 
improved by addition of a complex-forming agent. 
Mixtures of metal compounds that are soluble and insoluble in liquid 
hydrocarbons can also be used. 
Determination of the gelation time on a hot plate at 180.degree. C. is a 
very useful rapid test using simple equipment for a first indication of 
activity. Components (1) and (2) are mixed, for example, in a 80/20 weight 
ratio, with the metal compound to be tested, and the mixture is subjected 
to the gelation test. A mixture without accelerator will have a gelation 
time of 600 seconds or more, whereas satisfactory cure can be expected at 
gelation times of 400 seconds and below. The gelation test can be used to 
obtain a general indication of suitability of a metal compound or mixture, 
and for further selection of suitable components and their weight ratio. 
Only small samples will suffice (about 0.5 g of solids for each test), the 
compounding is very easy, and the result is available immediately after 
the test. 
The weight ratio of components (1) and (2) may vary between wide limits, in 
dependence of the reactivity of the components, the desired cure schedule, 
and the desired properties of the cured coating; the optimum ratio can be 
determined as usual; as a general guide line that weight ratio can be 
chosen from 90:10 to 50:50, and more particular from 80:20 to 60:40. 
The components can be mixed simultaneously or in any order that would be 
more convenient. The components and/or the compositions may be diluted 
with suitable volatile organic solvents, for example to regulate the 
viscosity or the solids content of the final paint or lacquer. 
Conventional paint additives may be incorporated, such as pigments, 
fillers, dispersants, stabilizers, flow control agents, and the like. 
The lacquers or paints can be applied by usual methods, such as by brush, 
roller, by spraying, dipping, and the like onto a variety of materials, 
preferably metals, such as bare steel, phosphated steel, zinc, tin plate 
(as a can lacquer), as the case may be as the sole coating layer or as a 
primer or top coat. For use as electrodeposition primers the component or 
components having amine groups is/are protonized by neutralizing 20 to 
100% of the amino functions with an acid, preferably an organic carboxylic 
acid, such as formic acid, acetic acid, citric acid or preferably lactic 
acid. These protonized binders may be used in 2-20% by weight in aqueous 
dilutions, solutions or dispersions in cathodic electrodeposition baths. 
The compositions may first be diluted with a water-soluble organic solvent 
such as a glycol ether, for example to simplify the neutralization or the 
dilution with water. The aqueous electrodeposition baths may also contain 
conventional additives, such as pigments, fillers, dispersants, 
stabilizers, flow control agents, and the like. The baths can be used for 
applying coatings to steel that has or has not been phosphated. 
The invention is illustrated by the following illustrative examples. Parts 
therein are parts by weight, unless otherwise stated or apparent from the 
context. Analytical data (amino, epoxy, hydroxyl) are based on 
non-volatile matter. 
Polyether D is a commercial solid glycidyl polyether of 
2,2-bis(4-hydroxyphenyl)propane having an epoxy molar mass of 472, a 
hydroxyl content of 0.29 equivalent per 100 g, and a molecular weight (Mn) 
of about 900. 
Glycidyl ester ClOE is a commercial glycidyl ester of saturated aliphatic 
monocarboxylic acids, wherein the carboxyl group is attached to a tertiary 
or quaternary carbon atom and which monocarboxylic acids have an average 
10 carbon atoms per molecule; the glycidyl ester has an epoxy equivalent 
weight of 250. 
Impact resistance or impact strength (IS) is the reversed impact strength, 
determined according to the British Standard Falling Ball Test, but 
recorded in cm.kg; &gt;90 cm.kg indicates very good cure. Salt spray 
resistance was according to ASTM-B 117-64 and recorded as mm.loss of 
adhesion from scratch after the number of days indicated. MEK rubs is the 
number of rubs to be given to cured coating with a cloth wetted with 
methyl ethylketone (MEK). MEK rubs 50 is an indication for good cure.

EXAMPLE I 
Hydroxyl-Containing Resinous Compounds, Used for Further Examples 
(a) Adduct of Polyether D, monoethanolamine, and diethanolamine. Polyether 
D (1888 parts, 4 epoxy equivalents) was melted and reacted with a mixture 
of monoethanolamine (61 parts, 1 mol.) and diethanolamine (210 parts, 2 
mol.) at 140.degree.-145.degree. C. during 3 hours. The hot liquid adduct 
was poured onto aluminum foil and allowed to cool. The solid brittle 
product had a residual epoxy content below 0.01 eq./100 g; the calculated 
molar weight 2160. 
(b) Linear polyether/amine adduct in solution. To a solution of Polyether D 
(2832 parts, 6 epoxy equivalents) in ethylene glycol monobutyl ether (1610 
parts) were added diethanolamine (210 parts, 1 mol.), 
3-(N,N-dimethylamino)propylamine (102) parts, 1 mol.) and an adduct of 
1,6-diamino hexane and glycidyl ester ClOE (616 parts, 1 mol. adduct). 
This adduct had been prepared by reacting 1,6-diamino hexane (1160 parts, 
10 mol.) with glycidyl ester ClOE (5000 parts, 20 mol.) at 80.degree. C. 
for 3 hours. The mixture of the Polyether and the amines was reacted by 
heating first at 85.degree.-90.degree. C. for 2 hours with stirring, and 
then at 120.degree. C. for 1 hour. The residual epoxy content was zero, 
N-content: 1.60 meq./g, OH-content: 0.56 eq./100 g, solids content: 70% w. 
The calculated molecular weight was 3760. 
(c) Linear polyether/amine adduct in solution. Prepared as in Example I (b) 
from the following ingredients: Polyether D (2832 parts, 6 epoxy 
equivalents), ethylene glycol monobutyl ether (1594 parts), 
diethanolamine (210 parts, 2 mol.), monoethanolamine (61 parts, 1 mol.), 
adduct of 1,6-hexane diamine and glycidyl ester ClOE (616 parts, 1 mol. 
adduct). 
The resulting adduct had a residual epoxy content of zero, an N-content of 
1.34 meq/g and an OH-content of 0.57 eq./100 g; solids content 70% w. The 
calculated molecular weight was 3720. 
(d) Resinous polyol RJ-100 was a commercial copolymer of styrene and allyl 
alcohol having a molecular weight of about 1150 and a hydroxyl content of 
0.45 eq./100 g. 
EXAMPLE II 
(a) Bis(2,3-dihydroxy propyl)azelate 
Azelaic acid 94 parts, 0.5 mol.) was heated to 120.degree. C. A catalyst, 
AMC-2 (commercial chromium salt, 0.8 g) was added. Glycidol (81.5 g, 1.1 
mol.) was added dropwise with stirring during 1 hour while keeping the 
temperature within 115.degree. and 125.degree. C. To complete the 
reaction, heating at 120.degree. C. was continued for another hour. The 
product was a viscous liquid which crystallized very slowly to a waxy 
solid. It had residual acid and epoxy contents of 0.03 and 0.07 meq./g, 
respectively, and a purity of about 95%; 2,3-dihydroxypropyl groups per 
molecule: 2; molecular weight; 336. 
(b) Oligomeric ester from terephthalic acid and glycerol, molar ratio 1:2 
Terephthalic acid (166 parts, 1 mol.), glycerol (184 parts, 2 mol.) and 
dibutyl tin oxide (1.75 parts) were heated at 210.degree.-245.degree. C. 
with stirring under a nitrogen blanket. Volatiles passed a steam-heated 
condenser and water was collected in a Dean & Stark trap. After 6 hours 36 
parts of water had been collected and the residual acid content was 0.10 
meq./g (degree of esterification &gt;98%). The resulting ester was a clear 
viscous mass, having two 2,3-hydroxypropyl ester groups per molecule. 
(c) Bis-(2-hydroxy-3-diethylaminopropyl)adipate 
Diethylamine (73 parts, 1 mol.) was added to ice-cold diglycidyl adipate 
(129 parts, 0.5 mol.) and the mixture was left in an ice bath for 3 hours. 
After standing at room temperature for 16 hours, the reaction was 
completed by warming to 40.degree. C. for 3 hours. The light-brown liquid 
product had an epoxy content of zero and an N-content of 4.80 meq./g 
(theory: 4.95); 2-hydroxy-3-diethylamino propyl groups per molecule: 2; 
molecular weight: 404 (calculated). 
(d) Bis-(2-hydroxy-3-diethylaminopropyl)terephthalate 
Diglycidyl terephthalate (145 parts, 1.0 epoxy equivalent) was dissolved in 
1,2-dimethoxyethane (145 parts). Diethyl amine (73 parts, 1 mol.) was 
added at room temperature. The mixture was heated at 60.degree. C. for 20 
hours and part of the solvent (75 parts) was stripped off in vacuo. The 
product, a light-brown viscous solution, had a solids content of 4.45 
meq./g theory: 4.59). 2-hydroxy-3-diethylaminiopropyl groups per molecule: 
2; molecular weight: 436 (calculated). 
(e) Tris-(2-hydroxy-3-diethylaminopropyl)trimellitate 
Triglycidyl trimellitate (166 parts, 1.0 epoxy equivalent) was mixed with 
1,2-dimethoxy ethane (102 parts) and diethyl amine (73 parts, 1 mol.). The 
mixture was heated at 50.degree. C. for 16 hours. The product, a brown 
viscous liquid, had a solids content of 70% w, an epoxy content of zero, 
and an N-content of 4.10 meq./g (theory: 4.18); 2-hydroxy-3-diethylamino 
propyl groups per molecule: 3; molecular weight: 717 (calculated). 
(f) Polyester from diglycidyl adipate and azelaic acid 
Diglycidyl adipate (65 g, 0.50 epoxy equivalents) and azelaic acid (47 g, 
0.25 mol.) were melted at 120.degree. C. Benzyl diemthylamine (catalyst, 
0.30 g) was added and the mixture was stirred at 150.degree.-160.degree. 
C. for 3 hours when the epoxy content was zero and the residual acid 
content was 0.23 meq./g. More diglycidyl adipate (3 g, 0.023 epoxy 
equivalent) was added and heating at 160.degree. C. was continued for one 
hour. The resulting polyester was a viscous, light-brown mass having an 
epoxy content of zero and an acid content of 0.08 meq/g. The molecular 
weight, determined by gel permeation chromatography (polystyrene 
calibration) was 10,200 (Mw). 
(g) Polyester from diglycidyl terephthalate and azelaic acid 
Diglycidyl terephthalate (147.5 g; 1.0 epoxy equivalent) and azelaic acid 
(94 g; 0.50 mol) were dissolved in methyl isobutyl ketone (161.5 g) by 
warming to 100.degree. C. Benzyl dimethyl amine (catalyst, 0.7 g) was 
added and the solution was stirred under reflux for 5 hours. The product 
was a viscous solution having a solids content of 60% w and residual epoxy 
and acid contents of 0.05 and 0.08 meq/g, respectively. The molecular 
weight (Mw) was 18,950 according to gel permeation chromatography. 
(h) Polyester from azelaic acid and glycerol 
Azelaic acid (451.2 g; 2.4 mol), glycerol (294.5 g; 3.2 mol) and dibutyl 
tin oxide (catalyst, 3.3 g) were heated at 180.degree.-220.degree. C. with 
stirring under a nitrogen blanket. Volatiles passed a stream-heated 
condenser and water was collected in a Dean & Stark trap. After 7 hours 86 
g (4.8 mol) of water were collected and the residual acid content was 0.18 
meq/g. The resulting polyester was a clear viscous mass with a molecular 
weight (Mw) of 5660 (GPC analysis). 
(i) Diester from dimer fatty acid and glycidol 
Prepared as in Example II(a) from dimer fatty acid (285 g; 1.0 COOH 
equivalent=0.5 mol), glycidol (81.5 g, 1.1 mol) and AMC-2 catalyst (1.8 
g). The liquid product had residual epoxy and COOH contents of 0.05 and 
0.01 meq/g, respectively. Molecular weight: 718; 2,3-dihydroxypropyl 
groups per molecule: 2. 
EXAMPLE III 
Reactivity of Various Polyester Cross-linking Agents in Combination with 
Hydroxyl-containing Resins 
All details and results have been collected in Table I. Hydroxyl-containing 
resins from Example I and cross-linking polyesters from Example II were 
blended in weight ratios as indicated, and thinned with ethylene glycol 
monobutyl ether to a solids content of 60% w. A metal salt catalyst 
(commercial 2-ethyl hexanoate salts of Pb.sup.2+, Zn.sup.2+ and Fe.sup.3+) 
was added to give a metal content of 0.67% w (on solid binder). The 
resulting lacquers were applied by wire rod applicator onto Anphosphated 
steel panels (0.7 mm thick) to obtain a dry-film thickness of 25-30 
micrometers. All coatings were stoved as specified in Table I and the 
degree of cross-linking achieved was assessed by evaluating 
Condition of hot film directly after stoving (liquid=l, or gelled=g), 
MEK rubs, and 
impact strength. 
TABLE I 
__________________________________________________________________________ 
Coatings as described in Example III 
Cross- 
link- 
Resin/ 
Hydro- 
ing cross- 
Ex- xyl-con- 
poly- 
linker 
per- 
taining 
ester 
weight 
Cata- 
Stoving Impact 
Cross- 
iment 
resin of 
of Ex- 
ratio 
lyst 
30 min. 
Hot 
MEK Strength 
link- 
No. Example 
ample 
(solids) 
type 
at .degree.C. 
film 
rubs 
cm.kg 
ing 
__________________________________________________________________________ 
1 I(a) II(a) 
79:21 
Pb 140 g .about.30 
&lt;5 .+-. 
2 I(a) II(a) 
79:21 
Pb 160 g &gt;50 &gt;90 ++ 
3 I(a) II(a) 
79:21 
Pb 180 g &gt;50 &gt;90 ++ 
4 I(a) II(a) 
79:21 
Zn 160 g &gt;50 &gt;90 ++ 
5 I(a) II(a) 
79:21 
Fe 160 g &gt;50 &gt;90 + + 
6 I(b) II(a) 
85:15 
Pb 140 g .about.50 
40-50 
+ 
7 I(b) II(a) 
85:15 
Pb 160 g &gt;50 &gt;90 ++ 
8 I(b) II(a) 
85:15 
Pb 180 g &gt;50 &gt;90 ++ 
9 I(b) II(a) 
85:15 
Zn 160 g &gt;50 &gt;90 ++ 
10 I(b) II(a) 
63:37 
Pb 160 g .about.25 
&lt;5 .+-. 
11 I(b) II(a) 
63:37 
Pb 180 g &gt;50 .about.20 
++ 
12 I(b) II(b) 
78:22 
Pb 160 g &gt;50 &gt;90 ++ 
13 I(b) II(b) 
78:22 
Pb 180 g &gt;50 &gt;90 ++ 
14 I(b) II(c) 
82:18 
Pb 180 g .about.25 
&lt;5 .+-. 
15 I(b) II(c) 
70:30 
Pb 180 g &gt;50 &gt;90 ++ 
16 I(a) II(d) 
71:29 
Pb 160 g .about.25 
&lt;5 .+-. 
17 I(a) II(d) 
71:29 
Pb 180 g &gt;50 &gt;90 ++ 
18 I(b) II(d) 
81:19 
Pb 160 g .about.50 
20-30 
+ 
19 I(b) II(d) 
81:19 
Pb 180 g &gt;50 &gt;90 ++ 
20 I(b) II(e) 
72:28 
Pb 160 g &gt;50 &gt;90 ++ 
21 I(b) II(e) 
72:28 
Pb 180 g &gt;50 &gt;90 ++ 
22 I(b) II(i) 
72:28 
Pb 160 g &gt;50 &gt;90 ++ 
__________________________________________________________________________ 
Conclusions from these data for the degree of cross-linking were: 
++ very good 
+ good 
.+-. moderate 
- poor. 
From the data in Table I it can be concluded that the reactivity of various 
polyesters is influenced by the substitution in the alkoxy part of the 
ester functions and that in particular esters containing 2,3-dihydroxy 
propyl groups are very active cross-linkers. 
EXAMPLE IV 
Cathodic Electrodeposition Paint 
The epoxy resin/amine adduct of Example I(b) (129.3 g; 90.5 g solids) was 
mixed with the polyester of Example II(i) (34.5 g), lead 2-ethyl hexanoate 
(2.5 g of a commercial product containing 33% Pb). and acetic acid (4.3 
g). Demineralized water (246 g) was added gradually to form a binder 
solution of 30% solids. 
A pigment paste was prepared by dispersing clay ASP-100 (10 g), talc (11.25 
g), carbon black (2.5 g) and lead silicate (1.25 g) with part of the 
binder solution (200 g) in a sand mill during 45 minutes. The pigment 
paste was thinned with the remainder of the above-mentioned binder 
solution (217 g) and finally with demineralized water (558 g) to give a 
black paint with a solids content of 15% w. 
The paint had a pH of 6.2 and a specific conductivity of 980 micro S/cm 
(25.degree. C.). The paint was electrodeposited cathodically onto 
degreased cold-rolled steel panels (0.7 mm thick) at a voltage of 50 V 
(direct current) during 2 minutes. The coated panels were rinsed with 
water and stoved as specified below. Smooth semi-glossy coatings were 
obtained which showed a good degree of cross-linking at stoving 
temperatures as low as 140.degree.-150.degree. C. 
______________________________________ 
Salt Spray 
Coating resistance 
Stoving thickness Impact (mm under- 
conditions 
micro- MEK strength 
rust after 
.degree.C./minutes 
meter rubs cm.kg 20 days) 
______________________________________ 
180/30 15-16 &gt;50 &gt;90 .about.5 
160/30 15-17 &gt;50 &gt;90 3-6 
150/30 15-17 &gt;50 &gt;90 3-5 
140/30 16-18 40-50 &gt;90 3-5 
______________________________________ 
EXAMPLE V 
Cathodic Electrodeposition Paint 
The epoxy resin/amine adduct of Example I(c) (144.6 g; 101.2 g solids) was 
mixed with the polyester of Example II(d) (31.3 g 23.8 g solids), lead 
2-ethyl hexanoate (2.5 g of a commercial product containing 33% Pb), 
polyacrylate flow control agent (0.1 g) and acetic acid (7.2 g). 
Demineralized water (261 g) was added gradually to form a binder solution 
of 28% solids. 
A pigment paste was prepared by dispersing clay ASP-100 (10 g), talc (11.25 
g), carbon black (2.5 g) and lead silicate (1.25 g) with part of the 
aqueous binder solution (200 g) during 45 minutes in a sand mill. 
The pigment paste was thinned with the remainder of the aqueous binder 
solution (246 g) and with demineralized water (529 g) to give a black 
paint with a solids content of 15% w. The paint had a pH of 6.4 and a 
specific conductivity of 2200 micro S/cm (25.degree. C.). 
The paint of this Example and the paint of Example IV were electrodeposited 
cathodically onto solvent-degreased cold-rolled steel panels at voltages 
specified in the Table during 2 minutes. The coated panels were rinsed 
with water and stoved at 180.degree. C. during 30 minutes. Smooth, 
semi-gloss panels were obtained which showed the following properties: 
______________________________________ 
Coating Salt Spray 
ED thick- resistance 
Paint volt- ness Impact (mm under- 
of age micro- MEK strength 
rust after 
Example 
pH V meter rubs cm.kg 28 days) 
______________________________________ 
V 6.4 100 16-18 &gt;50 &gt;90 1-2 
IV 6.2 50 14-17 &gt;50 &gt;90 6-10 
______________________________________ 
This Example demonstrates the very good salt spray resistance (28 days) 
obtained with a binder in which the polyester contains gamma(diethylamino) 
groups. 
EXAMPLE VI 
Evidence of Removal of Basic Material From Coatings During Stoving 
The paint of Example V was electrodeposited cathodically onto degreased, 
cold-rolled steel panels (110.times.70.times.0.7 mm) and the coated panels 
were dried in vacuo at 50.degree. C. until constant weight (5 hours). 10 
Panels (total coating weight 3.15 g) were then stoved in a closed glass 
container at 180.degree. C. during 30 minutes. Volatile material condensed 
on the glass walls after cooling was quantitatively recovered with 
methylene chloride. After evaporation of the methylene chloride, a residue 
of 0.41 g (13% of coating weight) was obtained. The IR-spectrum of the 
residue was virtually identical with that of 1-diethylamino-2,3-dihydroxy 
propane (prepared from equimolar amounts of diethylamine and glycidol). 
The amino content of the residue was high, 5.6 meq/g, indicating that a 
substantial amount of amine functionality had been removed from the 
coating during stoving. 
EXAMPLE VII 
Cathodic Electrodeposition Paints 
Epoxy resin/amine adduct of Example I(b), polyesters of Example II(f)-(h), 
lead-2-ethyl hexanoate (a commercial material containing 33% Pb), acetic 
acid and ethylene glycol monobutyl ether were blended in amounts specified 
in Table II. Demineralized water was added as specified to form aqueous 
solutions of 30% solids content. Part of these aqueous solutions (200 g) 
was used to disperse the following pigments in a sand mill during 45 
minutes: clay ASP-100 (10 g), talc (11.25 g), carbon black (2.5 g) and 
lead silicate (1.25 g). The resulting pigment pastes (Hegman fineness of 
grind &lt;10) were thinned with the remainders of the aqueous solutions (217 
g) and with demineralized water (558 g) to give black paints with the 
following characteristics: 
solids content: 15% w 
pigment/binder weight ratio: 0.20 
binder/organic solvent weight ratio: 70:30 
pH values and specific conductivities of these paints are given in Table 
II. The paints were electrodeposited cathodically onto degreased, 
cold-rolled steel panels at voltages of 150-200 V (direct current) during 
2 minutes. The coated panels were rinsed with water and pre-dried at 
50.degree. C./150 mbar until constant weight (5-7 hours). The coating 
weight was determined before and after stoving which took place at 
temperatures/times specified in Table II. Table II shows all coating 
properties evaluated. 
______________________________________ 
Paint No. (1) (2) (3) 
______________________________________ 
Adduct of Example I(b) 
157.1 157.1 157.1 
(solids content), g 
(110) (110) (110) 
Polyester of Example II(f), g 
15 -- -- 
Polyester of Example II(g), g 
-- 25+ -- 
Polyester of Example II(h), g 
-- -- 15 
Adduct/polyester weight ratio 
88:12 88:12 88:12 
Pb-2-ethyl hexanoate, g 
2.5 2.5 2.5 
Acetic acid, g 5.3 5.3 5.3 
Ethylene glycol mono- 
butyl ether, g 6.4 -- 6.4 
Water (30% solids) 
230.5 227 230.5 
Paint properties 
pH 6.0 5.9 6.0 
Specific condictivity 
micro S/cn (25.degree. C.) 
2165 2230 2165 
Coatings stoved at 
180.degree. C./30 min. 
Appearance smooth smooth smooth 
Thickness, micrometer 
19-21 16-18 17-21 
Weight loss, % w 9 10 9 
MEK rubs &gt;50 &gt;90 &gt;50 
Impact strength, cm.kg 
&gt;90 &gt;90 &gt;90 
Salt spray, mm rust creep 
(20 days) 3-5 4-6 4-6 
(20 days) 
Coatings stoved at 
160.degree. C./30 min. 
Appearance smooth smooth smooth 
Thickness, micrometer 
19-24 19-22 21-23 
Weight loss, % w 8 9 9 
MEK rubs &gt;50 &gt;90 &gt;50 
Impact strength, cm.kg 
&gt;90 &gt;90 &gt;90 
Salt spray, mm rust creep 
(20 days) .about.5 6-8 4-6 
______________________________________ 
+solution containing 15 g solids