U.S. patent application number 10/811349 was filed with the patent office on 2004-09-16 for anti-skinning agents having a mixture of organic compounds and coating compositions containing them.
Invention is credited to Manshausen, Peter, Steinert, Andreas.
Application Number | 20040177787 10/811349 |
Document ID | / |
Family ID | 7691415 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040177787 |
Kind Code |
A1 |
Steinert, Andreas ; et
al. |
September 16, 2004 |
Anti-skinning agents having a mixture of organic compounds and
coating compositions containing them
Abstract
The invention relates to anti-skinning agents containing
mixtures of organic compounds (combinations of additives), whereby
the organic compounds are selected from the groups of organic
hydroxylamines, and .beta.-dicarbonyl compounds and/or selected
derivatives of formic acid and also relates to compositions
containing them, especially oxidatively drying paints or coating
compositions.
Inventors: |
Steinert, Andreas;
(Langenfeld, DE) ; Manshausen, Peter; (Koln,
DE) |
Correspondence
Address: |
LANXESS CORPORATION
PATENT DEPARTMENT/ BLDG 14
100 BAYER ROAD
PITTSBURGH
PA
15205-9741
US
|
Family ID: |
7691415 |
Appl. No.: |
10/811349 |
Filed: |
March 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10811349 |
Mar 26, 2004 |
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10191382 |
Jul 8, 2002 |
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6730157 |
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Current U.S.
Class: |
106/263 ;
523/160 |
Current CPC
Class: |
C08K 5/07 20130101; C08K
5/17 20130101; C09D 7/46 20180101; C09D 11/03 20130101 |
Class at
Publication: |
106/263 ;
523/160 |
International
Class: |
C03C 017/00; C09D
101/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2001 |
DE |
10133727.2 |
Claims
What is claimed is:
1. An anti-skinning agent comprising a) an organic compound of
formula (I) 4where R.sup.1 and R.sup.2 mutually independently
represent hydrogen, a linear or branched, saturated or unsaturated
C.sub.1-C.sub.20 aliphatic radical, which can optionally be mono-
or polysubstituted, or a C.sub.6-C.sub.12 aryl radical, a
C.sub.7-C.sub.14 araliphatic radical or a C.sub.5-C.sub.7
cycloaliphatic radical, and either or both of b) an organic
compound of formula (II) 5where R.sup.3 represents hydrogen, a
hydroxyl radical, a saturated or unsaturated C.sub.1-C.sub.19
aliphatic radical, a C.sub.1-C.sub.7 alkoxy radical, or an amine
radical --NR.sup.7R.sup.8, R.sup.4 represents hydrogen, hydroxyl
radical, a saturated or unsaturated C.sub.1-C.sub.19 aliphatic
radical, a C.sub.1-C.sub.7 alkoxy radical, or an amine radical
--NR.sup.9R.sup.10, R.sup.7 and R.sup.8 mutually independently
represent hydrogen or a C.sub.1-C.sub.6 aliphatic radical, R.sup.9
and R.sup.10 mutually independently hydrogen or a C.sub.1-C.sub.6
aliphatic radical, and c) an organic compound of formula (III)
6where R.sup.5 represents hydrogen, a hydroxyl radical or a
C.sub.1-C.sub.7 alkoxy radical and R.sup.6 represents hydrogen or
an amine radical --NR.sup.11R.sup.12, R.sup.11 and R.sup.12
mutually independently represent hydrogen, C.sub.1-C.sub.6
aliphatic radical, or C.sub.5-C.sub.7 cycloaliphatic radical, or
amine radical --NR.sup.1R.sup.2 with the proviso that R.sup.5 and
R.sup.6 are not simultaneously hydrogen.
2. The anti-skinning agent of claim 1 further comprising water
and/or an organic solvent.
3. The anti-skinning agent of claim 1 wherein R.sup.3 represents a
substituted C.sub.1-C.sub.19 aliphatic radical, a substituted
C.sub.1-C.sub.7 alkoxy radical, or a substituted amine radical
--NR.sup.7R.sup.8, and R.sup.4 represents , a substituted
C.sub.1-C.sub.19 aliphatic radical, a substituted C.sub.1-C.sub.7
alkoxy radical, or a substituted amine radical --NR.sup.9R.sup.10,
R.sup.11 and R.sup.12 mutually independently represent a
substituted C.sub.1-C.sub.6 aliphatic radical, or a substituted
C.sub.5-C.sub.7 cycloaliphatic radical, or a substituted amine
radical --NR.sup.1R.sup.2.
4. The anti-skinning agent of claim 1 wherein the compounds of
formula (I) to (III) are in the form of aqueous dispersions or
emulsions.
5. A composition of matter comprising the anti-skinning agent of
claim 1.
6. The composition of matter of claim 5 wherein the amount of
anti-skinning agent is between 0.001 and 2.0 wt. % based on the
composition.
7. The composition of matter of claim 5 wherein the amount of
anti-skinning agent is between 0.01 to 0.5 wt. %, based on the
composition.
8. The composition of matter of claim 5 further comprising a
pigment.
9. The composition of matter of claim 5 wherein the composition is
a colorless or pigmented paint, a coating, a printing ink based on
oxidatively drying binders, an oxidatively drying paint system, or
a spraying agent in a printing ink.
Description
FIELD OF THE INVENTION
[0001] The invention relates to anti-skinning agents containing
mixtures of organic compounds (combinations of additives) and
coating compositions containing them. The organic compounds are
selected from the groups of organic hydroxylamines, and
.beta.-dicarbonyl compounds and/or selected derivatives of formic
acid. The invention further relates to compositions containing
these anti-skinning agents, like coating compositions such as
oxidatively drying paints.
BACKGROUND OF THE INVENTION
[0002] Colorless and pigmented oxidatively drying paints and
coatings based on oxidatively drying oils, alkyd resins, epoxy
esters and other oxidatively drying refined oils are known. These
oils and binders crosslink oxidatively under the influence of
oxygen (preferably atmospheric oxygen) by means of the addition of
driers, such as metal carboxylates of transition metals. If this
crosslinking takes place before the product is actually used, they
can form a solid binder film, a skin, on the surface when stored in
open or closed containers. This is highly undesirable and should
therefore be avoided since it makes the paint more difficult to
work with, and commonly interferes with the uniform distribution of
the driers. The accumulation of the driers in the paint skin that
forms can lead to considerable delays in the drying of the paint
when it is applied.
[0003] Skinning in the paint film after application is also
disadvantageous. Excessively rapid drying of the surface of the
paint prevents the lower film layers from drying evenly because
they are shielded from oxygen, which is prevented from sufficiently
penetrating into and dispersing within the paint film. This can
lead among other things to flow problems in the paint film,
adhesion problems, or insufficiently hard films.
[0004] It is known to add organic substances to the paint that
inhibit the reaction of the drier metal with (atmospheric) oxygen
by binding the oxygen or by complexing of the drier metal.
Formulations of known compounds that are suitable for this purpose
can be found e.g. in H. Kittel "Lehrbuch der Lacke und
Beschichtungen", Colomb Verlag 1976; J. Bieleman "Lackadditive"
Wiley VCH 1998 or Rompp Lexikon "Lacke und Druckfarben", Thieme
Verlag 1998.
[0005] Furthermore, DE-A 3 418 988 describes the use of aliphatic
.alpha.-hydroxy ketones as anti-skinning agents, and DE-A 1 519 103
discloses N,N-dialkylated hydroxylamines for this purpose. Because
of their low volatility, however, these agents can lead to severe
delays in drying and often also to reduced film hardness values, so
that their possible applications are limited. They have not been
able to gain acceptance as anti-skinning agents.
[0006] EP-A 0 903 380 describes the use of
.alpha.-keto-functionalised carboxylic acids and dicarboxylic acids
and of derivatives thereof, optionally in combination with diketo
compounds, as anti-skinning agents. A disadvantageous property of
such products lies in their limited stability and hence restricted
storage life.
[0007] Finally, pyrazole or imidazole derivatives, optionally in
combination with aliphatic diketones, in particular acetylacetone,
are recommended for this purpose in WO 00/11090. However, the cited
aromatic amines can cause severe discoloration in the coating
composition and also in the applied paint film and likewise give
rise to severe delays in drying.
[0008] Oximes (in particular butanone oxime) or suitable phenolic
compounds are mostly used today as anti-skinning agents in
industry. The phenolic anti-skinning agents display a significant
delay in surface drying, however, such that alone they are only
suitable for certain coating compositions. Oximes such as e.g.
methyl ethyl ketoxime or butyraldoxime, on the other hand, display
only slight delays in surface drying due to their volatility. The
most significant disadvantage of the oximes, which are widely used
today, lies in their toxicity. In long-term inhalation studies on
rats and mice, for example, an increased occurrence of liver tumors
was observed after exposure to butanone oxime, as a result of which
the German MAK committee has classified the substance as a category
III A 2 carcinogen (MAK list 1997) [MAK=maximum allowable
concentration in the workplace]. As a consequence of this, users
have to observe elaborate personal protection precautions when
working with paints containing oximes as anti-skinning agents.
[0009] It is an object of the present invention to develop organic
compounds which prevent skinning in paints and coating compositions
over an extended period and display only a slight delay in surface
drying. Furthermore, the film hardness values obtained in the
resulting films or coatings should not be negatively influenced and
no discoloration should be caused. The products should display no
disadvantageous toxicological properties.
[0010] It is another object of the invention that the organic
compounds can be incorporated into many different oxidatively
drying paints and coatings and by virtue of their physical
properties can be used straight-forwardly and for many purposes in
corresponding coating compositions.
[0011] Surprisingly it was found that these requirements could be
achieved by the use of mixtures containing the organic compounds
described below. In particular, the above-mentioned disadvantages
of the specified hydroxylamines as anti-skinning agents could also
be avoided by combining such substances with the additional
compounds described below, and hence products that better satisfy
requirements as anti-skinning agents are obtained.
[0012] In air-drying paints the mixtures according to the invention
are suitable for preventing undesirable skinning, for improving the
complete drying of paint films after application and for reducing
the tendency of the applied paint film to discolor.
SUMMARY OF THE INVENTION
[0013] The invention relates to an anti-skinning agent
containing
[0014] a) an organic compound of formula (I) 1
[0015] where
[0016] R.sup.1 and R.sup.2 mutually independently represent
hydrogen, a linear or branched, saturated or unsaturated
C.sub.1-C.sub.20 aliphatic radical, which can optionally be mono-
or polysubstituted, or a C.sub.6-C.sub.12 aryl radical, a
C.sub.7-C.sub.14 araliphatic radical or a C.sub.5-C.sub.7
cycloaliphatic radical, and either or both of
[0017] b) an organic compound of formula (II) 2
[0018] where
[0019] R.sup.3 represents hydrogen, a hydroxyl radical, a
substituted or unsubstituted, saturated or unsaturated
C.sub.1-C.sub.19 aliphatic radical, a C.sub.1-C.sub.7 alkoxy
radical, or an amine radical --NR.sup.7R.sup.8,
[0020] R.sup.4 represents hydrogen, hydroxyl radical, a substituted
or unsubstituted, saturated or unsaturated C.sub.1-C.sub.19
aliphatic radical, a C.sub.1-C.sub.7 alkoxy radical, or an amine
radical --NR.sup.9R.sup.10,
[0021] R.sup.7 and R.sup.8 mutually independently represent
hydrogen or a C.sub.1-C.sub.6 aliphatic radical,
[0022] R.sup.9 and R.sup.10 mutually independently hydrogen or a
C.sub.1-C.sub.6 aliphatic radical, and
[0023] c) an organic compound of formula (III) 3
[0024] where
[0025] R.sup.5 represents hydrogen, a hydroxyl radical or a
C.sub.1-C.sub.7 alkoxy radical and
[0026] R.sup.6 represents hydrogen or an amine radical
--NR.sup.11R.sup.12,
[0027] R.sup.11 and R.sup.12 mutually independently represent
hydrogen, substituted or unsubstituted C.sub.1-C.sub.6 aliphatic
radical, or substituted or unsubstituted C.sub.5-C.sub.7
cycloaliphatic radical, or amine radical --NR.sup.1R.sup.2
[0028] with the proviso that R.sup.5 and R.sup.6 are not
simultaneously hydrogen.
[0029] The invention also relates to compositions of matter
containing these anti-skinning agents.
DETAILED DESCRIPTION OF THE INVENTION
[0030] For the purposes of the invention mixtures of organic
compounds of formulae (I) to (III) are used alone or as solutions
or dispersions or emulsions in water and/or organic solvents.
Suitable organic solvents include all conventional solvents, such
as aromatics, white spirits, ketones, alcohols, ethers and fatty
acid esters.
[0031] For the use according to the invention the organic compounds
of formulae (I) to (III) can be used in a broad range of mixtures
with one another. They are preferably used in the ratio (I):(II) or
(III)=0.1:10 to 10:0.1 parts. In a mixture consisting of all three
components, each of the components can mutually independently
preferably be used in the ratio 0.1 to 10 to each of the other
components used. They can be used in pure form or in aqueous
solution or aqueous dispersion or emulsion or in the form of
solutions in organic solvents, whereby aqueous in this context is
intended to mean that water is either the sole solvent or is added
in a quantity of over 50 wt. % relative to the solvent blend
together with conventional organic solvents (e.g. alcohols).
[0032] The amount of anti-skinning agents primarily depends on the
content of binder and drier used in the particular coating
composition. As a general rule between 0.001 and 2.0 wt. % of
mixtures of compounds according to formulae (I) to (III) should be
added. Preferred amounts to be used are 0.01 to 0.5 wt. %, relative
in each case to the overall recipe of the coating composition. The
amounts can also depend on the type of binder and the pigments
used. Thus in special systems the relative amount of additive to be
used can also be greater than 2.0 wt. % (relative to the overall
recipe).
[0033] It is an advantage of the anti-skinning agent of the present
invention that it reliably prevent skinning in a wide range of
binders and when used with various driers but does not unfavorably
influence other drying properties of the paint.
[0034] The invention is further illustrated but is not intended to
be limited by the following examples in which all parts and
percentages are by weight unless otherwise specified.
EXAMPLES
[0035] The following embodiments of the mixtures of organic
compounds of formulae (I) to (III) that are suitable for use
according to the invention as anti-skinning agents are cited by way
of example:
[0036] a) 19% diethyl hydroxylamine, 22% diethyl formamide, 59%
water;
[0037] b) 19% diethyl hydroxylamine, 22% diethyl formamide, 59%
ethanol;
[0038] c) 15% diethyl hydroxylamine, 9% 2,4-pentane dione, 60%
ethanol, 16% water;
[0039] d) 19% diethyl hydroxylamine, 17.5% N-methyl acetoacetamide,
63.5% ethanol;
[0040] e) 10% diethyl hydroxylamine, 9% hydrazine ethyl
carboxylate, 79.5% ethanol, 1.5% water;
[0041] f) 25% dibenzyl hydroxylamine, 15% N-methyl acetoacetamide,
10% ethanol, 50% acetone;
[0042] g) 23% dibenzyl hydroxylamine, 10% diethyl formamide, 10%
ethanol, 57% acetone;
[0043] h) 10% diethyl hydroxylamine, 9% malonic acid, 10% diethyl
formamide, 60% ethanol, 11% water;
[0044] i) 10% diethyl hydroxylamine, 9% ethyl formiate, 50%
ethanol, 31% water;
[0045] j) 10% diethyl hydroxylamine, 10% ethyl acetoacetate, 78%
water;
[0046] k) 10% diethyl hydroxylamine, 9% dimethyl malonate, 60%
ethanol, 21% water;
[0047] l) 10% diethyl hydroxylamine, 9% malonic acid, 50% ethanol,
31% water;
[0048] m) 20% hydroxylamine, 15% N-methyl acetoacetamide, 30%
ethanol, 35% water;
[0049] n) 24% hydroxylamine, 11% hydrazine ethyl carboxylate, 25%
ethanol, 40% water.
[0050] Examples of the Use of Anti-Skinning Agents According to the
Invention
[0051] 1. 0.15 g of a cobalt-containing drier (trade name
Octa-Soligen Cobalt 6 from Borchers GmbH, contains 6 wt. % Co),
0.33 g of a zirconium-containing drier (trade name Octa-Soligen
Zirkon 18 from Borchers GmbH, contains 18 wt. % Zr) and 0.18 g of a
calcium-containing drier (trade name Octa-Soligen Calcium 4 from
Borchers GmbH, contains 4 wt. % calcium) were added to a coating
composition consisting of 25.0 g of a long-oil, high-gloss white
alkyd resin topcoat (binder solids content 68 wt. %). 0.018 g of
the mixture listed under a) was added to the formulation and the
time taken for a skin to form on the surface of a closed 125 ml PE
beaker filled to approx. 1/4 was established. Skinning was
prevented for 33 days in this case. By way of comparison, the
skinning time for a sample without anti-skinning additive
determined under identical conditions was 5 days, that for a sample
containing a conventional, suitable amount of butanone oxime (0.12
g) was 18 days. The color co-ordinate b* of a corresponding paint
film with a 100 .mu.m wet film thickness (according to CIELAB,
corresponding to DIN 6174) determined after a storage period of 1
week resulted in a value when the mixture according to the
invention was used that was 0.7463 points lower than the
tristimulus value of the sample containing butanone oxime,
determined under identical conditions, as a result of which a
reduced yellowing of the film was indicated.
[0052] 2. 0.38 g of a cobalt-containing mixed drier (trade name
Octa-Soligen Trockner 203 from Borchers GmbH, contains 1.2 wt. %
Co, 3.2 wt. % zinc and 7.2 wt. % barium) was added to a coating
composition consisting of 25.0 g of a high-gloss white alkyd resin
topcoat (binder solids content 36.9 wt. %). 0.046 g of the mixture
listed under c) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for more
than 27 days in this case. By way of comparison, the skinning time
for a sample without anti-skinning additive determined under
identical conditions was 2 days and that for a sample containing a
conventional, suitable amount of butanone oxime (0.041 g) was 10
days. The gloss of the paint film (according to DIN 67530)
determined after a storage period of 1 week was determined as 85.9
points (measured at 200) and 92.8 points (measured at 60.degree.)
when the mixture according to the invention was used. By way of
comparison, the gloss of the paint film from the sample without
anti-skinning additive determined under identical conditions was
81.6 points (measured at 20.degree.) and 88.5 points (measured at
60.degree.), that of the film from the sample containing butanone
oxime was 82.1 and 89.9 points (at 20.degree. and 60.degree.
respectively). The color co-ordinate b* of a corresponding paint
film with a 100 .mu.m wet film thickness (according to CIELAB,
corresponding to DIN 6174) determined after a storage period of 1
week resulted in a value when the mixture according to the
invention was used that was 0.300 points lower than the tristimulus
value of the sample containing butanone oxime, determined under
identical conditions, as a result of which a reduced yellowing of
the film was indicated.
[0053] 3. 0.10 g of a cobalt-containing drier (trade name
Octa-Soligen Cobalt 6 from Borchers GmbH, contains 6 wt. % Co) and
0.4 g of a calcium-containing drier (trade name Octa-Soligen
Calcium 4 from Borchers GmbH, contains 4 wt. % calcium) were added
to a coating composition consisting of 30.0 g of a long-oil alkyd
resin (trade name Alkydal U 601 from Bayer AG) and 2.2 g white
spirit D 60. 0.005 g of the mixture listed under d) was added to
the formulation and the time taken for a skin to form on the
surface of a closed 125 ml PE beaker filled to approx. 1/4 was
established. Skinning was prevented for more than 50 days in this
case. By way of comparison, the skinning time for a sample without
anti-skinning additive determined under identical conditions was 6
days, the skinning time for a sample containing a conventional,
suitable amount (0.05 g) of butanone oxime was 16 days and that for
a sample containing an identical amount (0.001 g) of diethyl
hydroxylamine in the same solvent was 7 days. The Konig pendulum
hardness (determined according to DIN 53 157, 100 .mu.m wet film
thickness) of a paint film to which the mixture according to the
invention had been added was 97 seconds after a storage period of 1
week. By way of comparison, the pendulum hardness of the paint film
from the sample without anti-skinning additive determined under
identical conditions was 96 seconds, that of the film from the
sample containing butanone oxime was likewise 97 seconds and that
of the film from the sample containing diethyl hydroxylamine was 93
seconds, in each case after a storage period of 1 week.
[0054] 4. 0.40 g of a cobalt-containing mixed drier (trade name
Octa-Soligen Trockner 203 from Borchers GmbH, contains 1.2 wt. %
Co, 3.2 wt. % zinc and 7.2 wt. % barium) was added to a coating
composition consisting of 30.0 g of a high-gloss white alkyd resin
topcoat (binder solids content 36.9 wt. %). 0.005 g of the mixture
listed under b) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for 42 days
in this case. By way of comparison, the skinning time for a sample
without anti-skinning agent determined under identical conditions
was 8 days, the skinning time for a sample containing a
conventional, suitable amount (0.05 g) of butanone oxime was 21
days and that for a sample containing an identical amount (0.001 g)
of diethyl hydroxylamine in the same solvent was likewise 21 days.
The drying time of a corresponding paint film (100 .mu.m wet film
thickness) from the mixture according to the invention was 12 h
(scratch drying according to test specification 100-94 from
Borchers GmbH). The drying time of a sample without anti-skinning
additive determined under identical conditions was 10 h 30 min.,
that of the sample containing butanone oxime was determined as 10
h. The drying time of the paint film from the sample containing
diethyl hydroxylamine was 14 h. The color co-ordinate b* of a
corresponding paint film with a 100 .mu.m wet film thickness
(according to CIELAB, corresponding to DIN 6174) determined after a
storage period of 1 week was 2.2754 when the mixture according to
the invention was used. The tristimulus values for the samples
without anti-skinning agent and with an identical amount (0.001 g)
of diethyl hydroxylamine in the same solvent determined under
identical conditions were 2.4214 and 2.4434 units respectively, as
a result of which a reduced yellowing of the coating composition
containing the mixture according to the invention was
indicated.
[0055] 5. 0.10 g of a cobalt-containing drier (trade name
Octa-Soligen Cobalt 6 from Borchers GmbH, contains 6 wt. % Co) and
0.4 g of a calcium-containing drier (trade name Octa-Soligen
Calcium 4 from Borchers GmbH, contains 4 wt. % calcium) were added
to a coating composition consisting of 30.0 g of a long-oil alkyd
resin (trade name Alkydal U 601 from Bayer AG) and 2.2 g white
spirit D 60. 0.023 g of the mixture listed under h) was added to
the formulation and the time taken for a skin to form on the
surface of a closed 125 ml PE beaker filled to approx. 1/4 was
established. Skinning was prevented for 22 days in this case. By
way of comparison, the skinning time for a sample without
anti-skinning additive determined under identical conditions was 3
days and that for a sample containing a conventional, suitable
amount of butanone oxime (0.05 g) was 10 days. The Konig pendulum
hardness (determined according to DIN 53 157, 100 .mu.m wet film
thickness) of a paint film to which the mixture according to the
invention had been added was 75 seconds after a storage period of 1
week. By way of comparison, the pendulum hardness of the paint film
from the sample without anti-skinning additive determined under
identical conditions was 73 seconds, that of the film from the
sample containing butanone oxime was 76 seconds.
[0056] 6. 0.18 g of a cobalt-containing drier (trade name Trockner
69 from Borchers GmbH, contains 6 wt. % Co and 9 wt. % zirconium)
and 0.4 g of a calcium-containing drier (trade name Octa-Soligen
Calcium 10 from Borchers GmbH, contains 10 wt. % calcium) were
added to a coating composition consisting of 40.0 g of a long-oil
alkyd resin (trade name Alkydal F 681 from Bayer AG), 4.0 g white
spirit D 60, 4.0 g xylene, 1.0 g n-butanol. 0.04 g of the mixture
listed under e) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for 102 days
in this case. By way of comparison, the skinning time for a sample
without anti-skinning additive determined under identical
conditions was 11 days, the skinning time for a sample containing a
conventional, suitable amount (0.10 g) of butanone oxime was 26
days and that for a sample containing an identical amount (0.004 g)
of diethyl hydroxylamine in the same solvent blend was likewise 26
days. The Konig pendulum hardness (determined according to DIN
53157, 100 .mu.m wet film thickness) of a paint film to which the
mixture according to the invention had been added was 41 seconds
after a storage period of 1 week. By way of comparison, the
pendulum hardness of the paint film from the sample without
anti-skinning additive determined under identical conditions was 29
seconds, that of the film from the sample containing butanone oxime
was 32 seconds and that of the film from the sample containing
diethyl hydroxylamine was 37 seconds, in each case after a storage
period of 1 week.
[0057] 7. 0.38 g of a cobalt-containing mixed drier (trade name
Octa-Soligen Trockner 203 from Borchers GmbH, contains 1.2 wt. %
Co, 3.2 wt. % zinc and 7.2 wt. % barium) was added to a coating
composition consisting of 25.0 g of a high-gloss white alkyd resin
topcoat (binder solids content 36.9 wt. %). 0.069 g of the mixture
listed under i) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for more
than 21 days in this case. By way of comparison, the skinning time
for a sample without anti-skinning additive determined under
identical conditions was 2 days and that for a sample containing a
conventional, suitable amount of butanone oxime (0.041 g) was 10
days. The color co-ordinate b* of a corresponding paint film with a
100 .mu.m wet film thickness (according to CIELAB, corresponding to
DIN 6174) determined after a storage period of 1 week resulted in a
value when the mixture according to the invention was used that was
0.166 points lower than the tristimulus value of the sample
containing butanone oxime, determined under identical conditions.
At the same time a tristimulus value was obtained that was 0.3117
points lower than the tristimulus value of the sample without
anti-skinning agent determined under identical conditions, as a
result of which a reduced yellowing of the film was indicated. The
gloss of the paint film (according to DIN 67530) determined after a
storage period of 1 week was determined as 87.8 points (measured at
20.degree.) and 95.6 points (measured at 60.degree.) when the
mixture according to the invention was used. By way of comparison,
the gloss of the paint film from the sample without anti-skinning
additive determined under identical conditions was 81.6 points
(measured at 20.degree.) and 88.5 points (measured at 60.degree.),
that of the film from the sample containing butanone oxime was 82.1
and 89.9 points (at 20.degree. and 60.degree. respectively).
[0058] 8. 0.20 g of a cobalt-containing drier (trade name
Octa-Soligen Cobalt 6 from Borchers GmbH, contains 6 wt. % Co),
0.25 g of a zirconium-containing drier (trade name Octa-Soligen
Zirkon 18 from Borchers GmbH, contains 18 wt. % Zr) and 0.46 g of a
calcium-containing drier (trade name Octa-Soligen Calcium 10 from
Borchers GmbH, contains 10 wt. % calcium) were added to a coating
composition consisting of 40.0 g of a high-gloss white alkyd resin
topcoat (binder solids content 38 wt. %). 0.092 g of the mixture
listed under k) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for more
than 28 days in this case. By way of comparison, the skinning time
for a sample without anti-skinning additive determined under
identical conditions was 5 days and that for a sample containing a
conventional, suitable amount of butanone oxime (0.162 g) was 21
days. The Konig pendulum hardness (determined according to DIN
53157, 100 .mu.m wet film thickness) of a paint film to which the
mixture according to the invention had been added was 79 seconds
after a storage period of 1 week. By way of comparison, the
pendulum hardness of the paint film from the sample without
anti-skinning additive and that of the film from the sample
containing butanone oxime, determined under identical conditions,
was in each case 76 seconds after a storage period of 1 week. The
color co-ordinate b* of a corresponding paint film with a 100 .mu.m
wet film thickness (according to CIELAB, corresponding to DIN 6174)
determined after a storage period of 1 week resulted in a value
when the mixture according to the invention was used that was 0.293
points lower than the tristimulus value of the sample containing
butanone oxime, determined under identical conditions, as a result
of which a reduced yellowing of the film is indicated when the
mixture according to the invention is used.
[0059] 9. 0.20 g of a cobalt-containing drier (trade name
Octa-Soligen Cobalt 6 from Borchers GmbH, contains 6 wt. % Co),
0.25 g of a zirconium-containing drier (trade name Octa-Soligen
Zirkon 18 from Borchers GmbH, contains 18 wt. % Zr) and 0.46 g of a
calcium-containing drier (trade name Octa-Soligen Calcium 10 from
Borchers GmbH, contains 10 wt. % calcium) were added to a coating
composition consisting of 40.0 g of a high-gloss white alkyd resin
topcoat (binder solids content 38 wt. %). 0.092 g of the mixture
listed under l) was added to the formulation and the time taken for
a skin to form on the surface of a closed 125 ml PE beaker filled
to approx. 1/4 was established. Skinning was prevented for more
than 28 days in this case. By way of comparison, the skinning time
for a sample without anti-skinning additive determined under
identical conditions was 5 days and that for a sample containing a
conventional, suitable amount of butanone oxime (0.162 g) was 21
days. The Konig pendulum hardness (determined according to DIN
53157, 100 .mu.m wet film thickness) of a paint film to which the
mixture according to the invention had been added was 78 seconds
after a storage period of 1 week. By way of comparison, the
pendulum hardness of the paint film from the sample without
anti-skinning additive and that of the film from the sample
containing butanone oxime, determined under identical conditions,
was in each case 76 seconds after a storage period of 1 week. The
film brightness L of a corresponding paint film with a 100 .mu.m
wet film thickness (according to CIELAB, corresponding to DIN
6174), determined after a storage period of 1 week, resulted in a
value when the mixture according to the invention was used that was
0.318 points higher than the value for the sample containing
butanone oxime, determined under identical conditions, as a result
of which a higher film brightness in the coating containing the
mixture according to the invention was indicated.
[0060] Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may be limited
by the claims.
* * * * *