Material for deaerating coating systems

An aqueous composition for coating substrates which contains polymeric organic film formers containing a deaerating effective amount of a linear polymer having at least five side groups, each of which contains a silicon atom which is linked by way of a divalent hydrocarbon group to the polymer, each silicon atom carrying at least one R.sup.1 group of formula EQU O--[C.sub.n H.sub.2n O--].sub.x Q in which n is 2 to 8, x is 1 to 10 and Q is an alkyl radical with 1 to 10 carbon atoms, an aryl radical, an alkaryl radical, or an acyl radical with 2 to 18 carbon atoms, and the sum of the carbon and oxygen atoms of R.sup.1 is not less than 5, as well as the linear polymers themselves. Methods for preparation of such materials are also disclosed as well as their use.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a material for deaerating coating systems which 
are applied from an aqueous phase onto surfaces and which contain 
polymeric organic film formers. 
2. Description of the Prior Art 
On applying water-dilutable coating systems onto a substrate and during or 
after the evaporation of the water from the aqueous dispersion, very small 
gas bubbles, finely dispersed in the coherent coating film being formed, 
frequently develop as the film is drying. These bubbles are sometimes 
referred to in the art as a microfoam. A portion of these bubbles float to 
the surface of the film where they burst and cause no defects, provided 
that the film is still sufficiently flowable for levelling the surface 
defects. Another portion of the bubbles rises to the surface. However, 
these bubbles do not burst. Rather, as the vehicle film cures, these 
bubbles form a very thin surface skin which can easily be damaged 
mechanically. Other bubbles remain dispersed in the film. Such defects in 
a paint film are described as "pin holes". 
The phenomenon of this so-called microfoam is not to be compared with the 
behavior and appearance of a conventional, more or less finely dispersed, 
polyhedral foam. Known defoamers or antifoaming agents destroy the 
lamellae of such a foam, that is, the walls separating the individual foam 
bubbles, or prevent the formation of stable foam bubbles. In a microfoam, 
the individual, mostly spherical gas bubbles in water-dilutable coating 
systems are generally separated so far apart from each other, that no 
lamellae are formed between individual foam spheres. For this reason, 
known antifoaming agents generally fail to eliminate and remove the 
microfoam. The process of eliminating such microfoams is often referred to 
as deaerating. Further references to the differences in the behavior of 
spherical foam and polyhedral foam are given in "Ullmanns Encyclopadie der 
technischen Chemie" (Ullmann's Encyclopedia of Chemical Engineering), Vol. 
20, pages 441 ff. 
It is known that air bubbles, enclosed in hydraulic oils, lubricating oils 
or pickling fluids may be removed by additives. Such additives are 
described in German Auslegeschrift 23 05 257. These additives, however, 
fail to remove the microfoam from aqueous preparations. 
It is presumed that processes at the gas/liquid interface affect the 
deaeration. The deaeration is possibly affected by changes in the 
viscosity of the coating system at the interface with the gas bubbles. In 
any case, because of the different physical and/or chemical influences on 
the interfaces between liquid and gas, those skilled in the art cannot 
draw conclusions from the effectiveness of antifoaming agents which might 
be applicable to the effectiveness of deaerating agents. 
SUMMARY OF THE INVENTION 
We have discovered a material and method for use thereof which is highly 
effective in deaerating microfoams in aqueous coating films. The bubbles 
of the microfoam become highly mobile and easily float to the surface, 
burst, and level out in a quantitative manner. The materials of the 
present invention are particularly suitable for deaerating coating systems 
which are applied from an aqueous phase to surfaces and contain organic 
film formers. Generally, such coating systems are aqueous preparations of 
film-forming organic substances, which optionally may contain soluble or 
insoluble pigments. The inventive materials are therefore intended 
especially for primers, paints, finishes and similar coating materials. 
More particularly, we have discovered that such coating systems can be 
deaerated in a highly effective manner by addition of a composition which 
contains a linear polymer having at least five side groups, each of which 
contains a silicon atom which is linked by way of a divalent hydrocarbon 
group to the polymer, wherein each silicon atom carries at least one 
R.sup.1 group having the formula O--[C.sub.n H.sub.2n O--].sub.x Q, in 
which n=2 to 8, x=1 to 10 and Q is an alkyl radical with 1 to 18 carbon 
atoms, an aryl radical, an alkaryl radical, or an acyl radical with 2 to 
18 carbon atoms and wherein the sum of the carbon and oxygen atoms of 
R.sup.1 are not less than 5. 
The compositions are added to the coating system in quantities such that a 
deaerating effective amount of the polymer will be present in the coating 
system. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The polymers which are effective as deaerating agents, have a structure 
which may be described as having a comb structure. At least 5 groups are 
attached laterally to the linear back of the comb. The effectiveness of 
the compounds is presumably attributable to this structure of the 
polymeric molecule. 
Thus, by suitably selecting and constructing the linear polymer carrying 
the side groups, that is, the back of the comb, those skilled in the art 
have at their disposal a method for matching the material to the structure 
of the substrate, which is to be deaerated. 
The groups, linked laterally to the linear polymer, in each case have a 
silicon atom which is linked by way of a divalent hydrocarbon group to the 
linear polymer. The silicon atom of each side chain carries at least one 
R.sup.1 group, which corresponds to the formula O--[C.sub.n H.sub.2n 
O--].sub.x Q. Q is an alkyl radical with 1 to 18 carbon atoms, an aryl 
radical, an alkaryl radical or an acyl radical with 2 to 18 carbon atoms. 
The sum of the oxygen and carbon atoms of the O--[C.sub.n H.sub.2n 
O--].sub.x Q is not less than 5. Examples of Q radicals are the methyl, 
ethyl, propyl, isopropyl, butyl, isobutyl, decyl, dodecyl, oleyl, 
hexadecyl, phenyl, octylphenyl, nonylphenyl, dodecylphenyl, acetyl, or 
isobutyl radicals. 
The subscript n has a value of 2 to 8, the subscript x a value of from 1 to 
10. 
Especially preferred examples of R.sup.1 groups having the O--[C.sub.n 
H.sub.2n O--].sub.x Q formula are the radicals O--[C.sub.3 H.sub.6 
O--].sub.4 C.sub.6 H.sub.5 ; --OC.sub.2 H.sub.4 OC.sub.2 H.sub.5 ; 
--OC.sub.4 H.sub.8 OCH.sub.3 ; 
##STR1## 
Especially preferred are materials which contain a linear polymer to which 
lateral structural units of the formula 
##STR2## 
are linked. For these units, R.sup.1 has the meaning given above. R.sup.2 
and R.sup.3 may be the same or different and represent a CH.sub.3 -- or 
C.sub.2 H.sub.5 -radical, a lower alkoxy radical with 1 to 6 carbon atoms 
or the R.sup.1 radical. If R.sup.2 and/or R.sup.3 represents a lower 
alkoxy radical, attention must be paid to ensuring that the alkoxy radical 
does not hydrolyze in the aqueous coating system. If the coating systems 
have a neutral reaction in water, alkoxy radicals, with a low number of 
carbon atoms in the alkoxy radical, can be used without reservations. If, 
however, the coating system has an acidic reaction in the aqueous phase, 
the use of alkoxy radicals with 4 or more carbon atoms is recommended. 
R.sup.4 is a hydrogen or a methyl radical. Preferably, R.sup.4 is a 
hydrogen radical. 
In much the same way as the structure of the linear polymer can be adapted 
to the structure of the organic film former, it is advisable to adapt the 
lateral groups, and especially the O--[C.sub.n H.sub.2n O--].sub.x Q group 
to the coating system, and moreover, especially to the solvent, which 
ensures the film formation of the organic film former. If, for example, 
phenyl glycol is used as solvent, it is advisable to use a structure such 
as --O--[C.sub.3 H.sub.6 O--].sub.4 C.sub.6 H.sub.5 as the O--[C.sub.n 
H.sub.2n O--].sub.x Q group. If methoxybutanol is used as the film-forming 
solvent, the methoxybutoxy group proves to be particularly suitable as the 
R.sup.1 group. 
Especially preferred polymers, which are contained as active substances in 
the deaerating agents, can be characterized by the following formulas. 
For example, a polymer of formula 
##STR3## 
is particularly suitable for deaerating coating systems, which are based 
on acrylate resins. In the formula, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 
have the meanings already given. Z are terminal groups which hardly have 
any influence on the effectiveness of the polymers and are determined by 
the nature of the polymerization process. Examples of such groups are the 
hydrogen, C.sub.1 to C.sub.5 alkyl or alkenyl, or the phenyl radical. The 
two Z groups may be the same or different. 
The structure units which are important for the purpose of the present 
invention, are those which have the subscript u. In accordance with the 
definition, u is not less than 5. 
The linear polymer can additionally have chain forming M units. These M 
units are specified by the value of v, v being given by the quotient 
u/v.gtoreq.4. The quotient u/v preferably has a value of not less than 8. 
This means that preferred linear polymers are those in which the structure 
units described by the subscript u, are contained in predominant numbers. 
In the case of a copolymerization, the different units are distributed 
statistically, corresponding to their reactivities. Examples of M units 
are 
##STR4## 
Compounds of the aforementioned formula can be synthesized by known 
procedures by first of all synthesizing copolymers having the formula 
##STR5## 
Such polymers can be synthesized by known procedures by polymerizing, for 
example, 1,3-butadiene with organometallic catalysts which contain metals, 
such as, for example, Li, Na, Co, Mo, Ti, V or Al individually, or in 
admixture. Suitable processes are described, for example, in German 
Offenlegungsschrift No. 29 33 609 and in Markromol, Chem. 16, page 213, 
1955. 
Hydrogenchlorosilanes, for example, CH.sub.3 HSiCl.sub.2 or HSiCl.sub.3 or 
(CH.sub.3).sub.2 HSiCl, are then added to the copolymers by a 
hydrosilation reaction. At the end, the chlorine can be esterified with 
the HO[C.sub.n H.sub.2n O].sub.x Q compounds by themselves or in admixture 
with low molecular weight alcohols having 1 to 6 carbon atoms, the 
inventive substances which are suitable as deaerators, then being formed. 
Especially suitable are products based on polybutadiene with a high 
content of vinyl groups, that is, 
##STR6## 
groups. 
Other linear polymers, which are also very suitable, can be represented by 
the formula 
##STR7## 
The substituents R.sup.1, R.sup.2 and R.sup.3 and the subscripts u and v 
have the already-given meaning or the aforementioned values. The R.sup.5 
and R.sup.6 substituents are alkyl radicals, such as, for example, methyl, 
ethyl, hexyl or octadecyl radicals. They may be phenyl radicals or also 
represent the hydrogen radical. In this case, however, not more than 10 
mole percent of all silicon atoms contained in the polymeric molecule, can 
have a hydrogen radical and R.sup.5 and R.sup.6 cannot both be hydrogen. 
R.sup.5 and R.sup.6 methyl radicals are preferred. The Z radicals once 
again are terminal groups and, generally, are trimethylsilyl radicals. The 
aforementioned compounds can be synthesized by known procedures by 
synthesizing siloxanes having the formula: 
##STR8## 
by equilibrating suitable building blocks. In the preceding formula, Z 
preferably is (CH.sub.3).sub.3 Si-- and R.sup.5 and R.sup.6 preferably are 
CH.sub.3. Vinyl silanes, for example 
##STR9## 
are then added to this siloxane in a hydrosilylating reaction. 
Finally, the Si-Cl groups are esterified, as already explained just above, 
in order to obtain the products, which are to be used according to the 
invention. 
Like polymeric organosilicon compounds in general, these compounds lower 
the interfacial tension in a special manner. They are suitable for 
deaerating organocarbon as well as organosilicon coating systems. 
A further group of effective compounds is represented by the formula 
##STR10## 
The substituents R.sup.1, R.sup.2 and R.sup.3 and the subscripts u and v 
have the meaning or value already given. R.sup.7 is a hydrogen radical or 
an alkyl radical with 1 to 18 carbon atoms, preferably, the methyl 
radical. R.sup.7 can also represent the --CH.sub.2 OCH.sub.2 
CH.dbd.CH.sub.2 or the --CH.sub.2 OR.sup.8, R.sup.8 being an alkyl radical 
with 1 to 18 carbon atoms or a phenyl radical. Z once again represents 
terminal groups, preferably, lower alkyl groups with 1 to 4 carbon atoms, 
or trimethylsilyl groups. The compounds can be synthesized by known 
methods from the corresponding alkylene oxides. Usually alkylene oxides of 
the formula 
##STR11## 
are copolymerized with allyl glycidyl ether, using acidic or alkaline 
catalysts. Products of the following formula are formed 
##STR12## 
The Z group results from the starting molecule used, it is H, when a glycol 
of the formula below is used as the starter. 
##STR13## 
If a monofunctional alcohol, for example, C.sub.4 H.sub.9 OH, is used as 
starter, Z consists to the extent of 50 mole percent of C.sub.4 H.sub.9 
units and to the extent of 50 mole percent of H. OH groups in the molecule 
are generally blocked by esterification or etherification, for example, 
they can be trimethylsilylated, before the reaction with hydrogen silanes 
is carried out. The polyethers, containing allyl side groups, are 
hydrosilylated with hydrogenchlorosilanes, for example, CH.sub.3 
HSiCl.sub.2, (CH.sub.3).sub.2 HSiCl or HSiCl.sub.3. Finally, the SiCl 
groups are esterified, in order to arrive at the compounds which are to be 
used inventively. 
The inventive materials usually contain the aforementioned active 
substances as a solution in organic solvents. It is possible to produce 
preparations of relatively high concentration. For example, the inventive 
materials for deaerating may contain polymers, which have linear side 
chains, in amounts of 5 to 60 weight percent. The inventive materials may 
contain additional additives, which favor the deaerating effect. For 
instance, it has proven to be particularly advantageous to add to the 
inventive materials, hydrophobized, finely divided silica in amounts of 2 
to 30 weight percent, based on the preparation. The finely divided silica 
should have a BET surface area of at least 50 m.sup.2 /g. The finely 
divided silica is hydrophobized, advisably by siliconizing it, employing 
known procedures. 
The inventive materials are added to the water-dilutable coating systems in 
amounts of 0.05 to 1 weight percent, based on the vehicle. It is obvious 
to those skilled in the art that the solvent used, in which the linear 
polymers are dissolved, must be compatible with the solvents in which the 
coating systems are contained. 
The usual paint properties, such as, hardness, gloss and adhesion to the 
substrate, are not impaired by the inventive deaerating agents.

The synthesis of the active substances contained in the inventive 
materials, the preparation of the inventive deaerating agents and the use 
of these agents are shown in the following examples. 
EXAMPLE 1 
To a reactor, equipped with stirrer, reflux condenser, thermometer and 
dropping funnel, are added 2,000 g of 1,2-polybutadiene dissolved in 6,400 
g of toluene and having an equivalent weight of 60.14 g based on the vinyl 
group content and corresponding to the average formula: 
##STR14## 
This solution is heated with stirring to 60.degree. C., mixed at this 
temperature with 500 mg of hexachloroplatinic acid dissolved in 4 ml of 
tetrahydrofuran (catalyst solution) and heated to 75.degree. C. Then, 
4,208 g of methylhydrogen dichlorosilane (that is, 110% of the amount 
required for addition to the vinyl groups) are allowed to run in slowly. 
The rate of addition is controlled so that the temperature of the contents 
of the flask does not exceed 100.degree. C. After completing the addition 
of the silane, the reactants are kept for 1 hour at 100.degree. C., in 
order to complete the reaction. Subsequently, the excess methylhydrogen 
dichlorosilane and a part of the toluene are distilled off. The 
distillation is ended when the temperature of the vapors coming over 
reaches 110.degree. C. The remaining contents of the flask are cooled down 
and the solids content and the content of hydrolyzable chlorine, expressed 
as milliequivalents per g of solids, are determined on the toluene 
solution of the reaction material. 
The solution of the reaction product has a solids content of 44.1% and an 
acid value of 11.15 milliequivalents/g based on the solvent-free product. 
From these values, the equivalent weight of the solid is calculated to be 
89.69 g. 
In order to synthesize compounds having the formula 
##STR15## 
wherein u=33.31 
w=3.69 
u:w=9.027, 
for use in the present invention, 89.69 g of solids, corresponding to 
203.37 g of the 44.1% solution of the abovedescribed methylhydrogen 
dichlorosilane adduct on 1,2-polybutadiene are added in each case to a 
reactor equipped with stirrer, thermometer, reflux condenser and dropping 
funnel. A 20 weight percent solution of the ROH in toluene is allowed to 
flow in at 70.degree. C. within 1 hour. After the addition is completed, 
the reaction is allowed to continue for a further hour at 70.degree. C. 
The product is then cooled to about 40.degree. C. and the hydrogen 
chloride present in the reaction material is neutralized by the dropwise 
addition of triethylamine to the point of alkaline reaction. After the 
reaction product is cooled to room temperature, the precipitated 
triethylammonium hydrochloride is filtered off and the toluene is removed 
from the filtrate by distillation. The inventive substances remain in the 
residue. A number of polymers, synthesized by this process, are listed in 
the following table. 
TABLE 1 
______________________________________ 
Com- 
pound O[C.sub.2 H.sub.2n O].sub.x Q = 
______________________________________ 
1a O[C.sub.3 H.sub.6 O].sub.4C.sub.6 H.sub.5 
1b O[C.sub.2 H.sub.4 O].sub.1C.sub.6 H.sub.5 
1c 
##STR16## 
1d OC.sub.2 H.sub.4 OC.sub.2 H.sub.5 
1e OC.sub.4 H.sub.8 OCH.sub.3 
______________________________________ 
Polymers 1a to 1e, which are listed in Table 1, are incorporated in a 
concentration of 0.1 weight percent in a white paint, which is prepared 
from a poly(ethyl acrylate) dispersion and has a pigment volume 
concentration of about 18% and a solids content of 48%. In order to make 
the incorporation of the inventive compounds easier, 40 weight percent 
solutions of compounds 1a to 1e in a mixture of equal parts of ethylene 
glycol and solvent naphtha are prepared first and these solutions are 
incorporated into the plant with the help of a dissolver. 24 hours after 
mixing, 100 g of the paint are stirred in a 250 ml beaker for 1 minute 
with a turbine stirrer at 2,000 rpm and the paint is then applied with a 
200 .mu.m spiral blade on a clean, grease-free glass plate. After the 
plates have been allowed to dry in a dust-free room, they are illuminated 
from below with a strong light source and the number of very fine holes, 
described as "pinholes", is counted in a 100 cm.sup.2 area. Advisably, the 
film is examined with a magnifying glass. 
The result is summarized in Table 2. The numbers are the average values of 
three independently applied paint films. 
TABLE 2 
______________________________________ 
Number of Pinholes 
Compound per 100 cm.sup.2 
______________________________________ 
1a 4 
1b 7 
1c 12 
1d 4 
1e 10 
without additive 
several hundred 
______________________________________ 
EXAMPLE 2 
Before being dissolved in the mixture of equal parts of ethylene glycol and 
solvent naphtha, the compounds described in Example 1 are mixed with a 
conventional, commercial, hydrophobized silica, which has a specific 
surface area of 150 m.sup.2 and a primary particle size of approx. 15 nm. 
The mixture consists of 85 parts by weight of the compounds 1a to 1e and 
15 parts by weight of the hydrophobic silica. These mixtures are dissolved 
as described in Example 1 and added to the white paint. Testing is carried 
out by the method described in Example 1. The results are summarized in 
Table 3. 
TABLE 3 
______________________________________ 
Hydrophobic Silica- 
Containing Preparations 
Number of Pinholes 
of Compound per 100 cm.sup.2 
______________________________________ 
1a 0 
1b 2 
1c 4 
1d 0 
1e 0 
without additive several hundred 
______________________________________ 
EXAMPLE 3 
In a reactor, equipped with stirrer, thermometer, reflux condenser and 
dropping funnel, 200 parts by weight of a poly(allyl glycidyl ether) 
having the formula 
##STR17## 
wherein u=28.20 are dissolved in 400 parts by weight of toluene and heated 
with stirring to 60.degree. C. A solution of 400 mg of hexachloroplatinic 
acid in 4 ml of tetrahydrofuran is then added, followed by 212.0 g of 
methyldichlorosilane (that is, 110% of the amount required for addition to 
the allyl group), which is added dropwise. At the same time, the contents 
of the flask are heated to 100.degree. C. Upon completing the addition of 
the silane, the reaction mixture is held for 1 hour at 100.degree. C. in 
order to complete the reaction. The excess methylhydrogendichlorosilane 
and a portion of the toluene are then distilled off. The distillation is 
stopped when the vapors coming over have reached a temperature of 
110.degree. C. The adduct, dissolved in toluene and remaining in the 
reactor, has a solids content of 52.2 weight percent and an acid value of 
8.48 milliequivalents/g. From this, the conversion of allyl groups is 
calculated to be 99.4%. From this value, the average formula is calculated 
to be 
##STR18## 
wherein u=28.03 
w=0.17 
u/w=164.88 
In order to synthesize inventive compounds of formula 
##STR19## 
117.9 parts by weight of the methylhydrogendichlorosilane adduct, prepared 
in the manner described above, or 226.9 parts by weight of the 52.2 weight 
percent solution in toluene, are added to a reactor which is equipped with 
stirrer, thermometer, reflux condenser and dropping funnel, and heated to 
70.degree. C. A solution of 359.0 parts by weight of C.sub.6 H.sub.5 
--[OC.sub.3 H.sub.6 --].sub.4 OH in 500 g of toluene, corresponding to 
110% of the theoretically required amount, is then added dropwise. At the 
end of the addition, the reaction is allowed to continue for 1 hour at 
70.degree. C. The reaction mixture is then cooled to 40.degree. C. and the 
hydrogen chloride remaining in the mixture, is neutralized by the dropwise 
addition of triethylamine until an alkaline reaction is obtained. The 
mixture is then cooled to room temperature, the precipitated 
triethylammonium chloride is filtered off the the filtrate is freed from 
toluene by distillation. 
The residue is tested in the manner described in Example 1. No pinholes can 
be detected in 100 cm.sup.2 of paint film. 
EXAMPLE 4 
A reactor, equipped with stirrer, thermometer, reflux condenser and 
dropping funnel, is charged with 1,000 g of an 
.alpha.,.omega.-trimethylsilylpolymethylhydrogen siloxane having the 
formula 
##STR20## 
dissolved in 2,250 g of toluene and the temperature is raised to 
90.degree. C. Then 200 mg of hexachloroplatinic acid, which is dissolved 
in 4 ml of tetrahydrofuran, is added and 2,448 g of methylvinyl 
dichlorosilane (that is, 110% of the amount required for addition to the 
SiH groups) is allowed to run in during 1 hour. While the silane is being 
added, the temperature rises to 108.degree. C. When all the silane has run 
in, the reaction is allowed to continued for 1 hour at the refluxing 
temperature. The excess methylvinyl dichlorosilane and a portion of the 
toluene are then distilled off, until a total of about 1,700 g of 
distillate has been removed. The adduct, dissolved in the toluene and 
remaining in the reactor, has a solids content of 80.9 weight percent and 
an acid value of 9.77 milliequivalents/g, based on the solvent-free 
product. This corresponds to practically a complete addition of the SiH 
used to the methyldichlorosilane. The compound formed can accordingly be 
assigned the following average formula: 
##STR21## 
From the acid value, an equivalent weight of 102.35 g can be calculated for 
the solid. 
In order to prepare inventive compounds of the general formula 
##STR22## 
156.4 parts by weight of the 80.9% toluene solution of the above-described 
adduct, corresponding to one SiCl equivalent, are reacted in each case 
with compounds having OH groups in the manner described in Example 1. 
A series of polymers, synthesized by this process, are listed in Table 4. 
TABLE 4 
______________________________________ 
Compound OR.sup.1 .dbd. OR.sup.2 
______________________________________ 
4a --O[C.sub.3 H.sub.6 O].sub.4 C.sub.6 H.sub.5 
4b --OC.sub.2 H.sub.4 --OC.sub.2 H.sub.5 
4c --O--C.sub.4 H.sub.8 --OCH.sub.3 
______________________________________ 
The polymers 4a-4c, listed in Table 4, are tested for their deaerating 
effect by the procedure described in Example 1. 
The results are given in Table 5. 
TABLE 5 
______________________________________ 
Number of Pinholes 
Compound per 100 cm.sup.2 
______________________________________ 
4a 2 
4b 6 
4c 4 
without additive 
several hundred 
______________________________________ 
COMISON EXAMPLE (similar to DE-AS 23 05 257) 
The following compounds are introduced at a level of 0.1 weight percent and 
in the form of a 40% solution in a mixture of equal parts of ethylene 
glycol and solvent naphtha into the white paint described in Example 1. 
##STR23## 
The paints were tested in the manner described in Example 1 and compared 
with an additive-free paint film. The number of pinholes per 100 cm.sup.2 
is approximately the same in all three samples. A deaerating effect cannot 
be detected.