Water-dilutable lacquer binders based upon alkyd and acrylate resins

This invention is directed to water-dilutable alkyd and acrylate resins. More particularly, this invention is directed to a method for the preparation of water-dilutable resin preparations based upon alkyd and acrylate resins which comprises the steps of: PA1 (a) preparing an aqueous alkyd resin dispersion, wherein the alkyd resin has an acid number of from about 5 to 40 and a hydroxyl number of from about 150 to 300 and the dispersion has a solids content of from about 30 to 90 percent by weight; and PA1 (b) polymerizing monomers of acrylic acid derivatives or methacrylic acid derivatives in the dispersion from step (a), optionally in the presence of additional water, to obtain a total solids content of from about 30 to 80 percent by weight, the weight ratio of alkyd resin to acrylate resin being from about 1:4 to 9:1. This invention is also directed to the use of these binders in water-dilutable lacquer systems.

FIELD OF THE INVENTION 
This invention is directed to water-dilutable alkyd and acrylate resins. 
More particularly, this invention is directed to water-dilutable alkyd and 
acrylate resins, to ecologically acceptable water lacquers prepared 
therefrom, and to the preparation of said resins and lacquers. 
BACKGROUND OF THE INVENTION 
In the field of stove-drying lacquers, environmental considerations have 
attained great importance. Thus, it is desirable to formulate products 
which during stoving release no or a minimum of volatile, 
atmosphere-polluting substances, such as solvents. One way of doing this 
is to use what are known as water lacquers, which are water-dilutable 
resin preparations based upon neutralized binder resins. To formulate a 
resin as a water lacquer, it is generally necessary to use adjuvants, such 
as, for example, solvents, volatile amines, or emulsifiers. Naturally, the 
type and quantity of adjuvants used depends upon the chemical nature of 
the resin. There has been no lack of efforts to find systems wherein these 
adjuvants are either dispensed with entirely or at least in part or can be 
replaced by ecologically acceptable substances. 
With regard to alkyd resin-based binders, these efforts have led to systems 
which even under stoving conditions do not release volatile, 
atmosphere-polluting components. Moreover, emulsifiers are known which 
lose their hydrophilic properties in the stoving process, thus ensuring 
the desired water stability of the lacquer coatings. Systems of this kind 
are described, for example, in German published applications (DE-OS) Nos. 
27 10 992, 27 10 993, 27 10 994, 27 11 000, 27 11 001, 27 11 002, 27 54 
092, 27 54 093, 27 54 140, and 27 54 141. 
For lacquers with acrylate-based binders, it is, however, extremely 
difficult technically to dispense with auxiliary solvents and common 
emulsifiers which do not lose their hydrophilic properties during stoving. 
(The terminology "acrylate resins" is understood to encompass copolymers 
of acrylic and/or methacrylic acid and their esters as well as styrene and 
other common comonomers, such as acrylonitrile.) The content in such 
resins of components which interfere either in processing (solvents) or in 
such finished lacquers (emulsifiers) is due to the method of production. 
They are normally produced either by polymerization in solution or by 
emulsion polymerization. In both cases, due to the resinous consistency of 
the products--which is desirable in itself--it is extremely difficult to 
separate adjuvants. Another product method, namely, polymerization of the 
monomers en masse, can be handled on an industrial scale only in very 
expensive equipment because of the high exothermicity and rapidly 
increasing viscosity. 
Acrylate lacquers have a number of desirable technical properties, such as, 
for instance, high chemical resistance, mechanical stability, and good 
polishability. For solvent lacquers, their use in combination with other 
resins, for instance alkyd resins, is known. This is taught, for example, 
in European Patent Application No. 6,517. There was a need, therefore, to 
also provide water lacquers which combine the favorable properties of 
ecologically acceptable alkyd resin binders with the favorable technical 
properties of acrylate resins. In the prior art only acrylate preparations 
were available for this which contained residual solvents, volatile 
amines, or those emulsifiers which do not lose their hydrophilic 
properties under stoving conditions. At best products purified by 
expensive methods or polymerized en masse could have been used. 
OBJECTS OF THE INVENTION 
It is an object of this invention to provide modified alkyd and acrylate 
resins. 
It is also an object of this invention to provide lacquer systems based 
upon alkyd and acrylate resins which are suitable as binders for 
water-dilutable, preferably stove-drying, lacquer systems, which do not 
contain emulsifiers that have an effectiveness that survives stoving or 
that adversely affect water stability of the lacquer systems, and which do 
not release any volatile amines or solvents. 
It is a further object of this invention to provide a lacquer system having 
typical favorable characteristics of acrylate resin systems, namely, high 
mechanical load capacity, good polishing capacity, and resistance to 
chemical attack, as well as typical favorable characteristics of alkyd 
resin systems, namely, good brilliance, luster, and body, while avoiding 
disadvantages of acrylate resin systems, such as the tendency of such 
systems to be irregular during spreading. 
It is a yet further object of this invention to provide a method of 
preparing a lacquer system wherein, in a first stage, a water-dilutable 
alkyd resin dispersion is prepared which has an acid number of from about 
5 to 40 and a hydroxyl number of from about 150 to 300 as well as a solids 
content of from about 30 to 90 percent by weight and, in a second stage, 
monomers of acrylic acid and/or methacrylic acid derivatives are 
polymerized, optionally after addition of water, in the alkyd resin 
dispersion, to obtain a total solids content of from about 30 to 80 
percent by weight, the weight ratio of alkyd resin to acrylate resin being 
from about 1:4 to 9:1. 
These and other objects of the invention will become more apparent in the 
discussion below. 
DETAILED DESCRIPTION OF THE INVENTION 
According to the invention, suitable lacquers based upon alkyd and acrylate 
resins are provided by polymerization of monomers which are normally used 
for the production of acrylate resins, in aqueous alkyd resin dispersions 
without volatile adjuvants and without non-stovable emulsifiers. The alkyd 
resin dispersions prepared according to the invention are finely divided 
microemulsions with particle sizes of from about 0.01 to 0.5 .mu. or 
colloidal resin solutions, respectively. Such preparations are described, 
for instance, in U.S. Pat. No. 4,271,051, incorporated herein by 
reference. The preparations appear clear or slightly opaque and 
homogeneous. When they are diluted with water, at least to a solids 
content of 50 percent by weight, the appearance does not change. It has 
now been surprisingly found that these alkyd resin dispersions constitute 
a suitable medium for the polymerization of acrylate monomers, the alkyd 
resin dispersions functioning in the same manner as an organic solvent 
mixture. 
Alkyd resin dispersions suitable as polymerization media are characterized 
primarily by the specific adjuvants used. As to the resins themselves, 
short-oil and medium-oil alkyd resins with acid numbers of from about 5 to 
40, preferably from about 20 to 30, can be used. For example, alkyd resins 
with acid numbers of from about 5 to 30 and with OH numbers larger than 
200, are known. These resins are generally formulated with the specific 
emulsifiers which lose their hydrophilic properties during stoving. 
However, suitable alkyd resins with acid numbers around 40 are also known 
which generally have a very much lower OH number, that is, from about 150 
to 300. Because of their higher acid numbers, such resins can usually be 
formulated without the aid of emulsifiers. Naturally, mixtures and 
transitions between these two resin types are also known and suitable. 
Further suitable are oil-free polyesters that can be formulated to water 
lacquers, such as, in particular, those resins for the preparation of 
which non-terminal or terminal olefin oxides with more than 8 carbon atoms 
have been used and acid group-containing alkyd resins which have been 
modified with other resins, for example, epoxy resins, phenolic resins, 
silicone resins, or reaction products of isocyanates. The only 
prerequisite for the above-mentioned resins is that they can be formulated 
with the mentioned adjuvants to form aqueous resin preparations which have 
a solids content greater than 60 percent by weight, preferably greater 
than 40 percent by weight, and which are so homogeneous that they appear 
essentially clear to the eye. 
According to the invention, the preparation of the alkyd/acrylates is 
affected by adding monomers to the aqueous alkyd resin preparations, 
either singly or in mixture, batchwise or continuously, under such 
conditions that radical polymerization can take place. Suitable monomers 
include amine salts of polymerizable acids, such as acrylic acid, 
methacrylic acid, and itaconic acid; esters of said polymerizable acids 
with aliphatic alcohols, such as lower alkyl acrylates and methacrylates, 
for example, butyl acrylate and butyl methacrylate; and lower alkylol 
esters of said polymerizable acids, such as lower alkylol acrylates and 
methacrylates, for example, 2-hydroxyethyl methacrylate. Methyl 
methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate, and butyl 
acrylate are particularly useful. Small amounts of the polymerizable 
acids, such as acrylic acid or methacrylic acid, may be present in the 
comonomer mixtures. Further suitable monomers include acrylonitrile and 
acrylamide. The use of monomers containing carboxyl groups or hydroxyl 
groups is particularly advantageous if cross-linking or hardening agents, 
such as hexamethylol melamine or similar preliminary condensates of 
melamine-formaldehyde, are used in the production of the lacquer system. 
According to another aspect of the invention, a portion of the monomeric 
acrylic acid or methacrylic acid derivatives can be replaced by radically 
polymerizable unsaturated hydrocarbons, such as styrene, 
.alpha.-methyl-styrene, or butadiene. Preferably up to 60 percent by 
weight, more preferably, from about 5 to 40 percent by weight, of the 
monomer mixture charged may consist of styrene. 
It is known that the hardness and flexibility of acrylate lacquers 
primarily depends upon the monomers used. Thus, an increased proportion of 
methyl methacrylate and/or styrene brings about rather hard coatings, 
while a larger proportion of butyl acrylate or ethyl acrylate gives soft 
flexible coatings. Further, to obtain a lower molecular weight and hence a 
lower viscosity of the lacquer, the addition of so-called regulators is 
known. Compounds with free mercapto groups, such as thioglycolic acid, are 
commonly used as regulators. 
If hexamethylol melamine ethers or similar melamine formaldehyde 
condensates are used for hardening the lacquers, it is advisable to use an 
amount of monomers with hydroxyl groups or of amine salts of polymerizable 
acids sufficient for the condensation. Those skilled in the art can 
determine the proper amount by a few preliminary tests. Thus, for example, 
an acrylate which is composed so that it has a hydroxyl number of 80 and 
an acid number of 20, can be regarded as suitable. 
The alkyd resins thus produced can be neutralized with condensable amines 
which have a high boiling point. Preferably adducts of glycidol are used 
for this purpose. Such amines containing suitable hydroxyl groups for 
neutralization include, for example, the adducts of glycidol onto 
butylamine, ethanolamine, as well as 2-amino-2-methyl-propanol, as are 
disclosed in U.S. Pat. No. 4,259,219, incorporated herein by reference. 
The amines are not volatile under stoving conditions and are incorporated 
into the lacquer through existing hydroxyl groups. 
To initiate the polymerization in the aqueous alkyd resin preparations, 
common initiators can be used. However, to avoid having inorganic salts, 
which are not desired in lacquers, remain in the preparations, organic 
initiators from the group consisting of azo compounds and organic 
peroxides are preferred. One skilled in the art would be familiar with a 
plurality of such compounds with a broad area of application with respect 
to the polymerization temperature. Examples of such compounds include 
azoisobutyric nitrile, benzoyl peroxide, and lauryl peroxide, as well as 
the other radical-supplying peroxide systems such as ammonium 
peroxodisulfate or potassium peroxodisulfate, optionally together with a 
reducing agent such as sodium sulfite or sodium dithionite. 
The mentioned monomers are partly quite soluble in water but also partly 
soluble only in organic solvents. It was therefore surprising and in no 
way predictable that the mentioned aqueous alkyd resin dispersions could 
be mixed with the required monomer quantities without a phase separation 
occurring. Instead, the systems also remain homogeneous during the 
polymerization, that is, the systems comprise clear 
solutions/microemulsions or also finely divided sedimentation-stable 
dispersions without coagulate content. 
Nothing is known about the structure of the acrylate resins formed by 
polymerization in aqueous alkyd dispersions, particularly with regard to 
the extent chemical bonds to alkyd resin molecules form. It is presumed, 
however, that statistically macromolecules of the acrylate resin are 
formed and that these macromolecules are present in intimate mixture with 
the alkyd resin molecules. In any event, desegregation processes were not 
observed during either heating or cooling of the preparations. 
According to a preferred embodiment of the invention, microemulsions known 
from U.S. Pat. No. 4,271,051 are used as polymerization medium. This is a 
system which contains alkyd resin of relatively low molecular weight with 
an acid number of from about 5 to 30 and a hydroxyl number greater than 
200 in the presence of a non-volatile neutralization agent and an 
emulsifier which does not lose its effectiveness during stoving. 
Such alkyd resins are produced by reacting known raw materials, for 
example, mixtures of natural fatty acids or dicarboxylic or tricarboxylic 
acids, such as phthalic acid, trimellitic acid, adipic acid, sebacic acid, 
terephthalic acid, or the like, with polyhydric alcohols, such as 
glycerol, neopentyl glycol, diethylene glycol, or trimethylolpropane, 
under esterification conditions. The procedure is to first condense to an 
acid number of from 30 to 180 and then, in a second stage, to esterify to 
a residual acid number below 30 by addition of glycidol. In this manner 
the resins obtain their high hydroxyl functionality. 
Examples of suitable non-volatile amines for neutralization are disclosed 
in U.S. Pat. No. 4,259,219. The glyceryl amines described there are 
characterized by high OH functionality. On stoving they become a lacquer 
component, as is also the case with the emulsifiers used. Advantageously 
nonionic emulsifiers are used. Emulsifiers which are formed by the 
addition of glycidol to nonylphenol or longer-chained monoamines or fatty 
alcohols are preferred. 
Instead of these emulsifiers, other emulsifiers with reactive groups in the 
molecule may be added which upon stoving lose their hydrophilic 
properties, for example, long-chain amino oxides. Since the reactive 
groups are chemically incorporated into the resulting film, their presence 
does not result in water-susceptibility of the finished lacquer film. 
According to a further preferred embodiment of the invention, water 
lacquers based on resins with an acid number of about 40 and a hydroxyl 
number of about 150 are used. Because of their high acid numbers, such 
resins generally do not require emulsifiers. 
For the production of the alkyd acrylates, first the aqueous alkyd resin 
dispersions are adjusted with water to a solids content of from about 30 
to 90 percent by weight, preferably from about 60 to 85 percent by weight, 
dependent upon viscosity. For a specific application, preliminary testing 
can be used to determine how much water must be added to obtain a suitable 
starting viscosity still conductive to polymerization. An expedient way to 
do this is to go by the viscosity at the polymerization temperature. 
Dependent upon the initiator used, the polymerization temperature is from 
about 40.degree. C. to the boiling point of the polymerization mixture. If 
especially high molecular weights are desired and if suitable initiators 
are used, polymerization is possible at room temperature or below. 
The monomers are added singly or in mixture, entirely or portion by 
portion. With reference to the copolymerization parameters, one skilled in 
the art can calculate which monomers must be added more quickly or more 
slowly to obtain a homogeneous statistical composition of the resin 
molecules, if this is desired. From 9 parts by weight of alkyd resin, per 
part by weight of acrylate resin, up to 4 parts by weight of acrylate 
resin, per part by weight of alkyd resin, can be produced in this way. It 
is, of course, possible also to produce only very small acrylate resin 
quantities in the alkyd resin, if this is desired. A weight ratio of alkyd 
resin to acrylate resin of from about 1:2 to 5:1 has proven particularly 
successful. To prevent an increase in viscosity during the polymerization, 
the product may be rediluted with water. Advantageously enough water is 
added during the polymerization for the total system to reach a solids 
content of from about 40 to 75 percent by weight. 
With the resin combinations producible according to the invention, 
virtually neutral water lacquers with a pH-value of from about 6 to 8 can 
be formulated. In this pH range the resins exhibit particularly good 
resistance to hydrolysis and, thus, good storage stability. The process 
products are suitable as such as binders for stove-drying, water-dilutable 
lacquer systems, but they can also be blended with other water lacquers in 
any desired ratio. 
For the stoving of the lacquers hardening components must be added. 
Melamine resins, which are available in great numbers, are suitable as 
hardening components. Especially suitable are solvent-free, or at least 
low-solvent, melamine resin preparations, particularly the 
water-compatible ones. 
The stoving of the lacquers is effected at temperatures of from about 
120.degree. to 175.degree. C., but preferably from about 135.degree. to 
165.degree. C., for a period of 10 to 40 minutes. Due to the special 
formulation described herein, practically no volatile component passes 
into the atmosphere. In some cases it is advisable to subject the lacquer 
systems produced according to the invention to a preliminary drying phase 
after application. After most of the water has evaporated, the stoving can 
be effected in drying ovens or drying tunnels. 
The lacquer systems according to the invention can be used for coating 
various materials, such as metal, glass, or even wood. Preferably the 
lacquer systems of the invention are applied as coating on steel, iron, 
aluminum, or one of the other materials frequently used in industry. 
The lacquer system according to the invention can also be pigmented in 
known manner.

The following examples are intended to illustrate the invention and should 
not be construed as limiting the invention thereto. 
EXAMPLES 
I. Preparation of Aqueous Alkyd Resin Dispersion 
Example 1 
Condensation was effected in known manner in a heatable glass apparatus 
equipped with agitator, water separator, and nitrogen supply, with the 
addition of xylene (80 ml) until the indicated acid number was reached. 
The reaction mixture consisted of the following: 
______________________________________ 
Mixture of fatty acids (1% myristic acid, 11% 
257.4 gm 
palmitic acid, 5% stearic acid, 23% oleic 
acid, 58% linoleic acid, 1% linolenic acid, 
and 1% arachic acid) 
Glycerol 84.6 gm 
Neopenthyl glycol 254.7 gm 
Phthalic acid anhydride 226.8 gm 
Trimellitic acid anhydride 176.4 gm 
______________________________________ 
The reaction mixture was polycondensed to an acid number of 95.5 at a 
maximum temperature of 190.degree. C. over a period of one and one-half 
hours. Thereafter, 994.4 gm of the condensate were reacted with 73.2 gm of 
glycerol to reach an acid number of 57.8. Then xylene was removed. 
Subsequently, glycidol was added onto this condensate with the acid number 
of 57.8 in a third reaction stage. An amount of 993.0 gm of the alkyd 
resin having an acid number of 57.8 was reacted with 30.0 gm of an amine 
(adduct of 1 mol of glycidol onto 1 mol of diethanolamine) and 48.3 gm of 
glycidol for ten minutes at 120.degree. C. The resulting alkyd resin, 
which had an acid number of 22.5, was then mixed hot with 5.3 gm of an 
adduct of 7.5 mols of glycidol onto 1 mol of nonylphenol as an auxiliary 
emulsifier and 7.4 gm of the adduct of 1 mol of glycidol onto 1 mol of 
diethanolamine, based upon 100 gm of alkyd resin. Subsequently the 
resulting alkyd resin was diluted with water to the desired active 
substance content. 
II. Polymerization in the Alkyd Resin Dispersion 
Example 2 
One hundred grams of a resin solution prepared according to Example 1 
having a solids content of 85 percent by weight, were charged into a 
standard polymerization apparatus (agitator, reflux condensor, nitrogen 
inlet and outlet, and drip funnel), and over a period of 90 minutes at 
temperatures of from about 85.degree. to 100.degree. C., the following 
mixture of monomers, regulator, and initiator was added dropwise: 
______________________________________ 
Methyl methacrylate 24.8 gm 
Butyl acrylate 18.6 gm 
2-Hydroxyethyl methacrylate 
10.5 gm 
Methacrylic acid 5.6 gm 
Thioglycolic acid 2.5 gm 
Azoisobutyronitrile (AIBN) 
0.6 gm 
______________________________________ 
After a post-reaction time of thirty minutes, 23 gm of the adduct of 2 mols 
of glycidol onto 1 mol of 2-amino-2-methylpropanol in 23 gm of water were 
added, and then, for improved stirrability, an additional 35 gm of water 
were added. The resulting resin solution was clear to slightly opaque, was 
infinitely water-dilutable, and had a solids content (including amines) of 
70 percent by weight. The alkyd/acrylate weight ratio was 1:1. 
Example 3 
Example 2 was carried out once more with the same alkyd resin quantity, 
that is, a solids content of 85 percent by weight, and under the same 
conditions, but the monomer quantities were as follows: 
______________________________________ 
Methyl methacrylate 6.5 gm 
Butyl acrylate 5.6 gm 
2-Hydroxyethyl methacrylate 
3.2 gm 
Methacrylic acid 2.7 gm 
Thioglycolic acid 0.8 gm 
AIBN 0.2 gm 
______________________________________ 
After a post-reaction time of thirty minutes, 9.5 gm of the adduct of 2 
mols of glycidol onto 1 mol of 2-amino-2-methylpropanol in 9.5 gm of water 
was added, and then an additional 4.5 gm of water were added for 
adjustment to 80 percent by weight solids. The resulting resin solution 
was clear and infinitely water-dilutable. The alkyd/acrylate weight ratio 
was 3:1, and the acid number of the acrylate component was 120. 
Example 4 
According to a procedure analogous to that of Example 2, a resin was 
prepared from the following: 
______________________________________ 
Methyl methacrylate 8.6 gm 
Butyl acrylate 6.4 gm 
2-Hydroxyethyl methacrylate 
3.6 gm 
Methacrylic acid 2.6 gm 
AIBN 0.2 gm 
______________________________________ 
Amounts of 7.2 gm of the adduct of 2 mols of glycidol onto 
2-amino-2-methylpropanol and 13.4 gm of water were added, the resulting 
solids content being 80 percent by weight. The resin solution was clear 
and infinitely water-dilutable, and the alkyd/acrylate weight ratio was 
3:1. The acid number of the acrylate component was 80. 
Example 5 
According to a procedure analogous to that of Example 2, a resin was 
prepared from the following: 
______________________________________ 
Methyl methacrylate 5.2 gm 
Butyl acrylate 3.8 gm 
2-Hydroxyethyl methacrylate 
2.2 gm 
Methacrylic acid 1.6 gm 
AIBN 0.1 gm 
______________________________________ 
Amounts of 4.3 gm of the adduct of 2 mols of glycidol onto 
2-amino-2-methylpropanol and 10.4 gm of water were added, the resulting 
solids content being 80 percent by weight. The resin solution was clear 
and infinitely water-dilutable, and the alkyd/acrylate weight ratio was 
5:1. 
Example 6 
According to a procedure analogous to that of Example 2, one hundred grams 
of a resin solution prepared according to Example 1, having a solids 
content of 50 percent by weight, were charged onto a standard 
polymerization apparatus as "solvent" for polymerization. The 
polymerization mixture was comprised as follows: 
______________________________________ 
Ethyl acrylate 13.9 gm 
Methyl methacrylate 22.0 gm 
2-Hydroxyethyl methacrylate 
8.2 gm 
Methacrylic acid 6.1 gm 
AIBN 0.5 gm 
______________________________________ 
Prior to addition of the polymerization mixture, 16.83 gm of the adduct of 
2 mols of glycidol onto 1 mol of 2-amino-2-methylpropanol dissolved in 
16.83 gm of water, were added. Fifty grams of water were added during the 
polymerization for better stirrability. 
The product obtained was a stable, white dispersion with a solids content 
of 50 percent by weight and an alkyd/acrylate ratio of 3:4 (in the 
neutralized form including amine). The dispersion was infinitely dilutable 
in water. 
Example 7 (Comparison) 
(a) An acrylate resin in emulsion was produced by known methods as follows: 
In a standard polymerization apparatus, 443 gm of water and 4 gm of lauryl 
alcohol-2-ethylene oxide-sulfate-Na-salt as well as 12 gm of thioglycolic 
acid were charged, and after flushing with nitrogen, the following 
monomers and initator were added dropwise at 90.degree. C. over a period 
of one hour: 
______________________________________ 
Methyl methacrylate 116 gm 
Butyl acrylate 87 gm 
2-Hydroxyethyl methacrylate 
50 gm 
Methacrylic acid 26 gm 
AIBN 3 gm 
______________________________________ 
The dispersion was subjected to a post-reaction for thirty minutes and then 
neutralized with 103 gm of the adduct of 2 mols of glycidol onto 
2-amino-2-methylpropanol in 166 gm of water. A cloudy resin solution with 
40 percent by weight solids content resulted. 
(b) By mixture of the alkyd resin from Example 1 with the acrylate resin 
from step (a), an alkyd acrylate with an alkyd/acrylate weight ratio of 
1:1 and a solids content of 50 percent by weight was produced. The resin 
solution was opaque. 
Example 8 (Comparison) 
According to procedures analogous to those of Example 7, an opaque resin 
solution with an alkyd/acrylate weight ratio of 3:1 and a solids content 
of 50 percent by weight was prepared. 
In Examples 2 to 6 above, the monomers polymerized have comprised various 
alkyl and alkylol acrylates or methacrylates as well as methacrylic acid. 
It should be noted that up to about 60 percent by weight, preferably from 
about 5 to 40 percent by weight, of said monomers could be replaced by 
polymerizable unsaturated hydrocarbons such as styrene or 
.alpha.-methylstyrene. 
III. Preparation of Lacquer Films 
For the production of lacquers, the products prepared according to Examples 
2 to 8 were mixed with hexamethyl ether of hexamethylol melamine (HMMM) as 
a cross-linking agent in amounts of 7 parts by weight of alkyd/acrylate 
product to 3 parts by weight of HMMM. Then the resulting solutions were 
adjusted to solids contents of 45 percent by weight. 
To test the lacquer film properties, the respective coating materials were 
spread on degreased steel plates and stoved at 150.degree. C. for 20 
minutes. The dry film thickness was 50.mu.. All the lacquer films were 
clear, hard, and glossy. While the binders from Examples 2 to 6 resulted 
in coatings which did not present any disorders or irregularities in 
spreading, the plates coated with the comparison products from Examples 7 
and 8 showed strong cratering. 
Pendulum impact hardnesses according to DIN 53 157 were determined for the 
coatings. For Examples 2 to 6, the impact hardnesses were from 125 to 150 
seconds; for Examples 7 and 8, the impact hardnesses were 144 and 106 
seconds, respectively, with a strong dependence upon the measurement 
point. The deep-drawing test according to Erichsen gave values between 7.5 
and 10.0 mm, depending on the pendulum hardness. 
The preceding specific embodiments are illustrative of the practice of the 
invention. It is to be understood, however, that other expedients known to 
those skilled in the art or disclosed herein, may be employed without 
departing from the spirit of the invention or the scope of the appended 
claims.