Transparent cover layer for transparent glass or plastic substrate

A condensation-inhibiting transparent cover layer of soft elastic polyurethane for viewing windows or other transparent glass or plastic substrates. The reaction mixture for production of the cover layer contains, in addition to a trifunctional polyisocyanate and a trifunctional polyol, a difunctional sulfonated polyether polyol, i.e. one containing sulfonate groups, and a non-ionic tenside in the form of an ethoxylated fatty alcohol and/or an ethoxylated fatty amine.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention pertains to a transparent cover layer of soft elastic 
polyurethane for viewing windows or other transparent glass or plastic 
substrates, with a condensation-inhibiting effect. 
2. Background of the Prior Art 
Transparent soft elastic cover layers with a condensation-inhibiting effect 
are the object of the German patent application P 37 04 294. On the one 
hand, they have the property of undergoing plastic deformation, which 
returns to the original state after a short period of time, under the 
usual type of stress, which would result in surface deformations and 
scratches in harder plastics. On the other hand, they have the advantage 
of demonstrating a marked condensation-inhibiting effect. The 
condensation-inhibiting effect is based on a synergistic effect of 
sulfonated polyether polyol, i.e. polyether polyol containing sulfonate 
groups, and a non-ionic polyether polysiloxane which as present as the 
same time, to which the reaction mixture which forms polyurethane is 
added. 
The condensation-inhibiting effect of these known cover layers is 
absolutely satisfactory at average temperatures. At temperatures below +10 
degrees Celsius and after extended contact with water, however, the 
condensation-inhibiting effect is not completely satisfactory at higher 
requirements. 
SUMMARY OF THE INVENTION 
The invention further improves the condensation-inhibiting effect of the 
known cover layers, so that they demonstrate the desired effect 
essentially without reduction also at temperatures below +10 degrees 
Celsius and after extended contact with water. 
In accordance with the invention, this task is accomplished in that the 
reaction mixture for formation of the cover layer contains the following 
components: 
(a) a trifunctional aliphatic polyisocyanate of 1,6-hexamethylene 
diisocyanate with a biuret or isocyanurate structure with a content of NCO 
groups of 12.6 to 28% by weight, corresponding to an average molecular 
weight of approximately 1000 to approximately 450 g/mol; 
(b) a trifunctional polyol prepared from trimethylolpropane and propylene 
oxide with a content of OH groups of 5.1 to 12.8% by weight, corresponding 
to an average molecular weight of approximately 1000 to approximately 400 
g/mol, or a trifunctional polycaprolactone with a content of OH groups of 
5.1 to 17% by weight, corresponding to an average molecular weight of 1000 
to 300 g/mol; 
(c) a difunctional sulfonated polyoxyalkylene ether, i.e. one containing 
sulfonate groups, of 1,2- or 1,3-diolene with a content of OH groups of 
0.5 to 13.2% by weight, corresponding to an average molecular weight of 
approximately 6500 to approximately 250 g/mol, with the formula 
EQU R-CH.sub.2 I--(C.sub.2 H.sub.4 O--).sub.n -(C.sub.3 H.sub.6 O--).sub.m 
-CH.sub.2 CH.sub.2 CH.sub.2 --SO.sub.3 X 
where 
##STR1## 
X=H-, sodium or ammonium ion, 
n=0 to 100, 
m=0 to 30, 
n+m.gtoreq.1; 
(d) non-ionic copolymer of dimethyl polysiloxane (dimethyl 
siloxane/monomethyl polyether siloxane copolymer) modified with 
polyoxyalkylene in the side chain, with an average molecular weight of 
approximately 500-2000 g/mol, with the general formula 
##STR2## 
where the ratio x/y=5/1 to 1/1, 
a=80-100% by weight, and 
b=20-0% by weight, and 
(e) at least one non-ionic tenside in the form of an ethoxylated fatty 
alcohol and/or an ethoxylated fatty amine. 
The amounts of the components forming the isocyanate component of the 
reaction mixture and the components forming the polyol component are to be 
selected in such a way that the ratio of NCO groups to OH groups is 1.0 to 
2.5. Preferably, the stated components of the reaction mixture are used in 
the following proportional amounts: trifunctional isocyanate 36 to 50% by 
weight, trifunctional polyol 42.5 to 18.7% by weight, difunctional 
sulfonated polyoxyalkylene ether, i.e. containing sulfonate groups, 4.8 to 
5.5% by weight, and non-ionic copolymer 3.8 to 4.8% by weight. 
DETAILED DESCRIPTION OF THE INVENTION 
It has been shown that with the composition of the reaction mixture 
according to the invention that in particular, the aging resistance of the 
cover layer is increased. It was particularly observed that the 
condensation-inhibiting effect is maintained for a longer period of time 
after the cover layer has been stored in water. Even if the 
condensation-inhibiting effect has been temporarily reduced after extended 
storage of the cover layer in water, at temperatures below +10 degrees C., 
the cover layer regenerates completely if it is stored at room temperature 
for some time, so that the original condensation-inhibiting effect is 
completely developed again. Even in the nonaged state, the cover layer 
according to the invention offers advantages as compared with the cover 
layer mentioned initially, in that it is less sensitive to deviations in 
the composition of the reaction mixture and in the polymerization 
conditions. 
As non-ionic tensides in the form of ethoxylated fatty alcohols, with a 
content of OH groups of 2.4 to 4.9% by weight, corresponding to an average 
molecular weight of 700 to 350 g/mol, with the formula 
EQU CH.sub.3 -(CH.sub.2).sub.n --O-(C.sub.2 H.sub.4 O).sub.m --H 
are particularly good possibilities, where n=10 to 16 and m=4 to 10. 
Especially good results are achieved with an ethoxylated fatty alcohol of 
this composition with an average molecular weight of approximately 480 
g/mol, corresponding to a content of OH groups of about 3.5% by weight; in 
this case, n=13 and m=6 in the chemical formula stated. 
As non-ionic tensides in the form of ethoxylated fatty amines, with a 
content of OH groups of 2.2 to 6.5% by weight, corresponding to an average 
molecular eight of 1600 to 520 g/mol, those of the formula 
##STR3## 
are particularly good possibilities, where n=10 to 16 and m=4 to 5. An 
ethoxylated fatty amine of this composition with an average molecular 
weight of approximately 1000 g/mol, corresponding to a content of OH 
groups of about 3.4% by weight, is preferred; in this case, n=13 and m=9. 
The proportion of the non-ionic tenside in the reaction mixture is 
preferably between 8.3 and 15.5% by weight in the case of the ethoxylated 
fatty alcohol and preferably between 11.0 and 18.5% by weight in the case 
of the ethoxylated fatty amine. 
Possible difunctional sulfonated polyether polyols, i.e. those containing 
sulfonate groups, are preferably polyether-1,3-diols with an average 
molecular weight of approximately 1300 g/mol. Such polyether polyols and 
methods for their production are described in greater detail in DE-PS 34 
07 563. 
In order to improve the mechanical properties of the soft elastic 
polyurethane cover layers, one can add a difunctional isocyanate urea 
adduct on the basis of isophorondiisocyanate to the reaction mixture, in 
addition, specifically in the amount of 4.0 to 18.7% by weight relative to 
the reaction mixture. 
In the same way, in order to improve the mechanical properties, a 
difunctional polyester polyol with a content of OH groups of 2 to 5% by 
weight, corresponding to an average molecular weight of 1700 to 680 g/mol 
can be added, to the reaction mixture, in the amount of 2.8 to 8.0% by 
weight relative to the reaction mixture, possibly in addition to the 
difunctional isocyanate urea adduct. 
For an evaluation of the mechanical/physical properties of the soft elastic 
polyurethane cover layers, the modulus of elasticity, the abrasion 
resistance and the microsclerometric hardness were determined as 
characteristic properties; in total, these permit a statement as to 
whether or not the cover layer demonstrates the necessary self-healing 
properties and the necessary behavior for use. The modulus of elasticity 
is determined as described in DIN 53.457. To determine the abrasion 
resistance, the method described in the ECE standard R-43 is used, by 
having two friction rollers with an abrasive effect act on the rotating 
sample for 100 revolutions, with a stress of 500 g. To evaluate the 
abrasion caused by this stress, the increase in cloudiness is then 
measured in comparison with the original cloudiness before treatment, 
indicated in %, also using the method described in the ECE standard R-43. 
The micro-sclerometric hardness is determined according to the Erichsen 
method, in which a test set-up is used as described in DIN 53.799, with 
the exception that the cone-shaped cutting diamond used has a cone angle 
of 50 degrees and a rounding radius of 15 micrometers at the cone tip. To 
evaluate the microsclerometric hardness, the highest load weight of the 
cutting diamond at which no permanently visible damage to the surface is 
evident yet is indicated. 
From experience, it is known that self-healing transparent polyurethane 
cover layers can be used as shatter protection layers if the modulus of 
elasticity of these layers is between 2 and 20 N/mm.sup.2, the increase in 
cloudiness due to abrasion is less than 4% according to ECE R-43, and the 
microsclerometric hardness according to Erichsen is above 10 p. Even 
hydrophilic cover layers are therefore only useful for practical 
continuous use if the properties stated lie within these limits. 
To evaluate the wetability of the cover layer and thereby the 
condensation-inhibiting effect, the wetting angle of water drops applied 
to the surface of the cover layer is measured using a goniometer 
microscope. For the stated cover layers of soft elastic polyurethane which 
have no condensation-inhibiting effect, the size of the wetting angle is 
70 to 80 degrees. For cover layers which do have a condensation-inhibiting 
effect, however, the size of the wetting angle is only a few degrees and 
can even be reduced to zero degrees. 
In the following, several embodiments are described within the scope of the 
claimed compositions, and the mechanical and condensation-inhibiting 
properties measured for these cover layers in each case are reproduced; 
here, Example 1 concerns a cover layer not in accordance with the 
invention and merely serves for comparison. 
In all embodiments, films are produced from the reaction mixtures, by 
pouring the reaction mixture, after homogenization, onto glass plates 
heated to about 60 degrees Celsius, in a layer thickness of 0.5 mm. The 
poured layer is allowed to cure for 30 minutes at a temperature of 90 
degrees Celsius. Subsequently, the films are pulled away from the casting 
surface. The films are then conditioned for 48 hours at a temperature of 
20 degrees Celsius and a relative humidity of 50%. 
The mechanical properties, that is the modulus of elasticity, the increase 
in cloudiness due to abrasion and the microsclerometric hardness, are 
determined at room temperature. 
The wetting angle as a measure of the wetting behavior is determined on two 
surfaces of the film in each case; the surface which was in contact with 
the glass surface is designated as Side A in the following, while the 
surface which was exposed to the surrounding air during the pouring and 
curing process is designated as Side B in the following examples The 
wetting angle is measured after three different pre-treatments of the film 
in some of the embodiments The first measurement (Measurement I) takes 
place after conditioning of the film, parallel to determination of the 
mechanical properties, at a temperature of 20 degrees Celsius. The second 
measurement (Measurement II) is carried out immediately after the first, 
at a temperature of +10 degrees Celsius. The third measurement 
(Measurement III) is also carried out at a temperature of +10 degrees 
Celsius, after the film has been placed in water at +10 degrees Celsius 
for 2 hours and subsequently dried for 16 hours at 20 degrees Celsius and 
50% relative humidity. For those embodiments which only contain one value 
for wetting behavior, the measurement was taken after conditioning of the 
film, at a temperature of 20 degrees Celsius.

EXAMPLE 1 (COMISON EXAMPLE) 
A cover layer is produced as described in the German patent application P 
37 04 294. To produce the reaction mixture, 50 g of an essentially 
trifunctional polyisocyanate containing biuret groups, on the basis of 
1,6-hexamethylene diisocyanate, with a content of free NCO groups of 23% 
by weight, corresponding to an average molecular weight of approximately 
550 g/mol, 42.5 g of a trifunctional polyol on the basis of 
trimethylolpropane with an OH content of 11% by weight, corresponding to 
an average molecular weight of approximately 500 g/mol, as well as 8.5 g 
of a difunctional polyether-1,3-diol containing sulfonate groups, with a 
content of OH groups of 2.6% by weight, corresponding to an average 
molecular weight of approximately 1300 g/mol, with the formula stated 
initially, are used, in which 
##STR4## 
X=sodium ion, 
n=20 and 
m=3. 
Furthermore, the reaction mixture contains 5 g of a non-ionic polyether 
polysiloxane (dimethyl siloxane/monomethyl polyether siloxane copolymer) 
with the formula stated initially, with an average molecular weight of 
approximately 700 g/mol, where the ratio is 
EQU x/y=1/1, 
a=100% by weight, and 
b=0% by weight. 
0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of a sterically 
inhibited amine as protection against the effects of light are added to 
the polyol. 
For the mechanical properties and the wetting behavior, the following 
values were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
8.1 .+-. 0.2 N/mm.sup.2 
increase in cloudiness due 
3.1% 
to abrasion 
microsclerometric hardness 
28 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 13 degrees 40 degrees 
Side B 5 degrees 20 degrees 42 degrees 
______________________________________ 
It is obvious that the wetting behavior under the conditions under which 
Measurements II and III were carried out is not satisfactory. 
EXAMPLE 1 
To produce a cover layer according to the invention, a reaction mixture is 
used, to which a difunctional polyether polyol containing sulfonate 
groups, as well as a non-ionic polyether polysiloxane, as well as in 
addition, an ethoxylated fatty alcohol as a non-ionic tenside, are added. 
For this purpose, 50 g of an essentially trifunctional polyisocyanate 
containing biuret groups, on the basis of 1,6hexamethylene diisocyanate, 
with a content of free NCO groups of 23% by weight, corresponding to an 
average molecular weight of approximately 550 g/mol, 25 g of a 
trifunctional polyol on the basis of trimethylolpropane with an OH content 
of 11% by weight, corresponding to an average molecular weight of 
approximately 500 g/mol, 8 g of a difunctional polyether-1,3-diol 
containing sulfonate groups, with a content of OH groups of 2.6% by 
weight, corresponding to an average molecular weight of approximately 1300 
g/mol, with the formula stated initially, are used, in which 
##STR5## 
X=sodium ion, 
n=20 and 
m=3, 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1, as well as 8 g of an ethoxylated fatty alcohol with the 
formula stated initially, with an average molecular weight of 
approximately 350 g/mol, corresponding to a content of OH groups of 4.9%, 
where n=10 and m=4 in the chemical formula, are mixed together As 
additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of a 
sterically inhibited amine as protection against the effects of light are 
added to the polyol. 
For the mechanical properties and the wetting behavior of this film, the 
following values were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
6.6 .+-. 0.4 N/mm.sup.2 
increase in cloudiness 
2.6% 
due to abrasion 
microsclerometric hardness 
26 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 5 degrees 5 degrees 
Side B 6 degrees 8 degrees 5 degrees 
______________________________________ 
The mechanical properties of this cover layer are therefore within the 
required limits. The wetting behavior at low temperatures, especially 
after water immersion, are significantly improved as compared with the 
comparison example. 
example 3 
A reaction mixture of the following components is produced: 
50 g of an essentially trifunctional polyisocyanate containing biuret 
groups, on the basis of 1,6-hexamethylene diisocyanate, with a content of 
free NCO groups of 23% by weight, corresponding to an average molecular 
weight of approximately 550 g/mol; 
29 g of a trifunctional polyol on the basis of trimethylolpropane with an 
OH content of 11% by weight, corresponding to an average molecular weight 
of approximately 500 g/mol; 
6 g of a difunctional polyether-1,3-diol containing sulfonate groups, with 
a content of 0H groups of 2.6% by weight, corresponding to an average 
molecular weight of approximately 1300 g/mol; 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1; 
12 g of an ethoxylated fatty alcohol with the formula stated initially, 
with a content of OH groups of 3.5% by weight, corresponding to an average 
molecular weight of approximately 480 g/mol, where 
n=13 and m=6 in the chemical formula. 
As additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of 
a sterically inhibited amine as protection against the effects of light 
are added to the polyol. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
7.4 .+-. 0.4 N/mm.sup.2 
increase in cloudiness 
3.1% 
due to abrasion 
microsclerometric hardness 
26 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 5 degrees 5 degrees 
Side B 5 degrees 9 degrees 7 degrees 
______________________________________ 
The mechanical properties of this cover layer are within the required 
limits. The wetting behavior at low temperatures, and especially after 
water immersion, are clearly improved as compared with the comparison 
example. 
EXAMPLE 4 
A reaction mixture of the following components produced: 
50 g of the trifunctional polyisocyanate stated for the preceding examples, 
with a content of free NCO groups of 23% by weight, corresponding to an 
average molecular weight of approximately 550 g/mol; 
29 g of a trifunctional polyol on the basis of trimethylolpropane with an 
OH content of 11% by weight, corresponding to an average molecular weight 
of approximately 500 g/mol; 
4 g of a difunctional polyether-1,3-diol containing sulfonate groups, with 
a content of OH groups of 2.6% by weight, corresponding to an average 
molecular weight of approximately 1300 g/mol, with the formula stated 
initially, where 
##STR6## 
X=sodium ion, 
n=20 and 
m=3, 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1; 
16 g of an ethoxylated fatty alcohol with the formula stated initially, 
with an average molecular weight of approximately 700 g/mol, corresponding 
to a content of OH groups of 2.4%, where n=16 and m=10 in the chemical 
formula. 
As additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of 
a sterically inhibited amine as protection against the effects of light 
are added to the polyol. For a film produced from this reaction mixture, 
the following values for mechanical properties and the wetting behavior 
are measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
4.5 .+-. 0.4 N/mm.sup.2 
increase in cloudiness 
2.2% 
due to abrasion 
microsclerometric hardness 
27 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 5 degrees 5 degrees 
Side B 5 degrees 7 degrees 5 degrees 
______________________________________ 
In this case again, the mechanical properties are within the required 
limits. The wetting behavior at low temperatures, and especially after 
water immersion, are clearly improved as compared with the comparison 
example. 
EXAMPLE 5 
The reaction mixture demonstrates the following composition: 
50 g of the trifunctional polyisocyanate stated for the preceding examples, 
with a content of free NCO groups of 23% by weight, corresponding to an 
average molecular weight of approximately 550 g/mol; 
20 g of a trifunctional polyol on the basis of trimethylolpropane with an 
OH content of 11% by weight, corresponding to an average molecular weight 
of approximately 500 g/mol; 
5 g of a difunctional polyether-1,3-diol containing sulfonate groups 
mentioned in Example 4, with a content of OH groups of 2.6% by weight, 
corresponding to an average molecular weight of approximately 1300 g/mol; 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1; 
15 g of an ethoxYlated fatty amine with the formula stated initially, with 
an average molecular weight of approximately 520 g/mol, corresponding to a 
content of OH groups of 6 5% by weight, where n=10 and m=4 in the chemical 
formula. 
As additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of 
a sterically inhibited amine as protection against the effects of light 
are added to the polyol. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior are measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
9.5 .+-. 0.8 N/mm.sup.2 
increase in cloudiness 
2.7% 
due to abrasion 
microsclerometric hardness 
33 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 5 degrees 6 degrees 
Side B 7 degrees 10 degrees 10 degrees 
______________________________________ 
This cover layer also demonstrates mechanical properties which are within 
the required limits. The wetting behavior at low temperatures, and 
especially after water immersion, is clearly improved as compared with the 
comparison example. 
EXAMPLE 6 
A reaction mixture of the following components is produced: 
50 g of the trifunctional polyisocyanate described in the preceding 
examples; 
28 g of the trifunctional polyol on the basis of trimethylolpropane 
described in the preceding examples; 
6 g of the difunctional polyether-1,3-diol containing sulfonate groups 
stated in Example 4; 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1; 
11 g of an ethoxylated fatty amine with the formula stated initially, with 
an average molecular weight of approximately 1000 g/mol, corresponding to 
a content of OH groups of 3.4% by weight, where n=13 and m=9. 
As additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of 
a sterically inhibited amine as protection against the effects of light 
are added to the polyol. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior are measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
8.3 .+-. 0.3 N/mm.sup.2 
increase in cloudiness 
1.8% 
due to abrasion 
microsclerometric hardness 
25 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 5 degrees 7 degrees 
Side B 8 degrees 10 degrees 11 degrees 
______________________________________ 
This cover layer again demonstrates properties which are within the 
required limits in terms of mechanical properties and which are clearly 
better with regard to wetting behavior at low temperatures and after water 
immersion, as compared with the cover layer of the comparison example 
EXAMPLE 7 
A reaction mixture of the following components is produced: 
50 g of the trifunctional polyisocyanate described in the preceding 
examples; 
25 g of the trifunctional polyol on the basis of trimethylolpropane 
described in the preceding examples; 
8 g of the difunctional polyether-1,3-diol containing sulfonate groups 
stated in Example 4; 
5 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer stated 
in Example 1; 
20 g of an ethoxylated fatty amine with the formula stated initially, with 
an average molecular weight of approximately 1570 g/mol, corresponding to 
a content of OH groups of 2.2% by weight, where n=16 and m=15. 
As additives, 0.05 g dibutyl stannous dilaureate as a catalyst and 1.0 g of 
a sterically inhibited amine as protection against the effects of light 
are added to the polyol. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior are measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 
6.3 .+-. 0.4 N/mm.sup.2 
increase in cloudiness 
2.7% 
due to abrasion 
microsclerometric hardness 
28 p 
Wetting behavior: 
Measurement I 
Measurement II 
Measurement III 
______________________________________ 
Side A 0 degrees 6 degrees 6 degrees 
Side B 4 degrees 8 degrees 7 degrees 
______________________________________ 
For this cover layer again, the wetting behavior at low temperatures and 
after water immersion are clearly better than for the cover layer of the 
comparison example, while the mechanical properties are also within the 
required limits. 
EXAMPLE 8 
A reaction mixture of the following components is produced: 
36.11 g of the trifunctional polyisocyanate described in Example 3; 
4.01 g of a difunctional isocyanate urea adduct on the basis of isophoron 
diisocyanate with a content of OH groups of 28% by weight, corresponding 
to an average molecular weight of 300 g/mol, 
32.78 g of a polycaprolactone with a content of OH groups of 9.5% by 
weight, corresponding to an average molecular weight of 537 g/mol, 
8.02 g of a difunctional polyester polyol with a content of OH groups of 
3.3% by weight, corresponding to an average molecular weight of 1030 
g/mol, 
4.81 g of a difunctional polyester polyol containing sulfonate groups, with 
a content of OH groups of 2.6% by weight, corresponding to an average 
molecular weight of approximately 1300 g/mol; 
10.03 g of an ethoxylated fatty alcohol with the formula stated initially, 
with a content of OH groups of 3.5% by weight, corresponding to an average 
molecular weight of approximately 480 g/mol, where n=13 and m=6, 
3.81 g of the dimethyl siloxane/monomethyl polyether siloxane copolymer 
stated in Example 1; 
0.019 g dibutyl stannous dilaureate, and 
0.39 g of a sterically inhibited amine as protection against the effects of 
light. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior are measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 6.2 N/mm.sup.2 
increase in cloudiness due to abrasion 
2.12 % 
microsclerometric hardness 
38 p 
Wetting behavior: 
Side A 
0 degrees 
Side B 
3 degrees 
______________________________________ 
For this cover layer again, the wetting behavior at low temperatures and 
after water immersion are clearly better than for the cover layer of the 
comparison example, while the mechanical properties are also within the 
required limits. 
EXAMPLE 9 
Of the components stated in Example 8, the following amounts are weighed 
out and the reaction mixture is produced from them: 
40.83 g trifunctional polyisocyanate 
10.21 g difunctional isocyanate urea adduct 
21.84 g polycaprolactone 
5.46 g difunctional polyester polyol 
5.46 g difunctional polyether-1,3-diol containing sulfonate groups 
10.92 g ethoxylated fatty alcohol 
4.75 g dimethyl siloxane/monomethyl polyether siloxane copolymer 
0.024 g dibutyl stannous dilaureate, and 0.50 g sterically inhibited amine. 
The reaction mixture has a ration of NCO/OH of 1.8. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 7.2 N/mm.sup.2 
increase in cloudiness due to abrasion 
2.56% 
microsclerometric hardness 
34 p 
Wetting behavior: 
Side A 
0 degrees 
Side B 
3 degrees 
______________________________________ 
EXAMPLE 10 
Of the components stated in Example 8, the following amounts are weighed 
out and the reaction mixture is produced from them: 
42.80 g trifunctional polyisocyanate 
10.70 g difunctional isocyanate urea adduct 
20.65 g polycaprolactone 
5.16 g difunctional polyester polyol 
5.14 g difunctional polyether-1,3-diol containing sulfonate groups 
10.32 g ethoxylated fatty alcohol 
4.71 g dimethyl siloxane/monomethyl polyether siloxane copolymer 
0.024 g dibutyl stannous dilaureate, and 0.50 g sterically inhibited amine. 
The reaction mixture has a ration of NCO/OH of 2.0. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 7.4 N/mm.sup.2 
increase in cloudiness due to abrasion 
3.74% 
microsclerometric hardness 
33 p 
Wetting behavior: 
Side A 
0 degrees 
Side B 
4 degrees 
______________________________________ 
EXAMPLE 11 
Of the components stated in Example 8, the following amounts are weighed 
out and the reaction mixture is produced from them: 
39.57 g trifunctional polyisocyanate 
18.71 g difunctional isocyanate urea adduct 
18.68 g polycaprolactone 
2.83 g difunctional polyester polyol 
4.97 g difunctional polyether-1,3-diol containing sulfonate groups 
9.89 g ethoxylated fatty alcohol 
4.81 g dimethyl siloxane/monomethyl polyether siloxane copolymer 
0.025 g dibutyl stannous dilaureate, and 0.50 g sterically inhibited amine 
The reaction mixture has a ration of NCO/OH of 2.5. 
For a film produced from this reaction mixture, the following values for 
mechanical properties and the wetting behavior were measured: 
______________________________________ 
Mechanical properties: 
modulus of elasticity 13.6 N/mm.sup.2 
increase in cloudiness due to abrasion 
3.90% 
microsclerometric hardness 
30 p 
Wetting behavior: 
Side A 
0 degrees 
Side B 
24 degrees 
______________________________________ 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.