Note: Descriptions are shown in the official language in which they were submitted.
2151175
FIELD OF lNv~.llON
The invention relates to a coating material for maæking
traces of wear, such as scratches, furrows, etc. on glass
surfaces, especially on reusable container glass.
r~ ROUND lN~ ~TION AND PRIOR ART
Glass cont~; nerS, which are filled, for example, with
beverages, such as milk, beer, fruit juice, mineral water or
lemonade, are largely reusable articles. After use, they are
supplied to the bottler by way of a collection system and filled
once again. During transport, as well as during the filling
process, the bottles su~er damage, which is caused mostly by
contact of the bottles with one another or by contact with
metallic surfaces. In order for these traces of wear to be
covered, the following conditions must be fulfilled by a coating
material:
- Good coverage of the scratched areas;
- Water resistance after a short period;
- Applicability even on moist bottles;
- Tack-free coating with a pleasant handle;
- No e~ect on labels, printing inks and label glues;
- Films completely removable by washing and non-critical
beha~ior irl the al~aline washing liq~or; and
- Toxicological safety.
N~-36092 1 2
2151175
The films must make it possible to cover the traces of
wear well and, at the same time, be resistant to water, because
the glass cont~;ners are frequently kept in refr.gerators and
refrigerated counters, so that resistance to con~enRation water
must be guaranteed. The application of film must function
satisfactorily on moist and cold bottles. The film must not be
tacky, since this is not accepted by the customer and it would
furthermore become contaminated by deposited dust. Thermal
curing of the ~lm is not realizable because of the high filling
speed; moreover, it could also a~ect the contenLs. It should be
possible to wash o~ the ~lm completely in an alkaline washing
solution.
Admittedly, methods for masking traces of wear have
been proposed, the marking material of which cannot be washed o~
by means of alkaline washing solution. However, these methods
are not advantageous, since the glass containers repeatedly are
filled, transported, emptied, collected and washed. A permanent
film would itself be damaged easily during these processes and
then show undesirable traces of wear. Moreover, in the course of
the washing process, the quality of this coating deteriorates and
finally becomes whitish-opaque, for example. Moreover, film
layers of up to 50~m are required here; for reasons of costs,
this is unacceptable for covering traces of wear.
NY2-36092.1
21~117~
In the literature, the state of the art that is
concerned with this problem has already been described
extensively. In US patent 4,273,834, a formulation is described,
which consists of a high-molecular weight polysiloxane resin,
which has methyl, phenyl and alkoxy groups on the silicon atoms
and is dissolved in hydrocarbon-containing solvents. From
hygienic and toxicological considerations, this method is not
convincing.
The use of low molecular weight and, therefore,
ethanol-soluble polyorganosiloxanes is described in US patent
3,547,673. The adhesion to the glass surface is improved by the
incorporation of amino-functional groups. The disadvantage of
this method, however, lies in the use of ~r~hle solvents. Due
to the use of the amino-functional groups, the coating of bottles
so treated shows clear indications of yellowing.
The use of modi~ed polyorganosiloxanes, which contain
functional groups, such as amino, mercapto and/or trialkoxysilyl
groups for improving the adhesion to the glass surface, is
described in the US patent 4,228,054. For this method, the
cross-linkable polyorganosiloxane is cured using a tin catalyst,
which is toxicologically questiona~le.
In US patent 4,656,221, the use of polysiloxanes in
combination with cationic and nonionic surfactants is described.
NY2-36092 . 1
2151175
A method based on polysilo~nes, which can be applied
in volatile polysiloxanes as solvent on the bottle surface, is
named in the EP-A-395 077.
In the EP-A-464 779, triglyceride emulsions are
described, which are produced using nonionic emulsi~ers and
additional par~n oil and silicone oil components.
The use of appreciable amounts of polysiloxanes is a
co~o~ feature of all the methods described in this state of the
art. Under washing condition with alkaline solutions, these
substances, however, are decomposed to volatile, ring-shaped
siloxane monomers D3, D4 and DS. In bottling operations, and
particularly in beer breweries, this effect is undesirable since
it can lead to foam stability problems. The use of polysiloxanes
is therefore critical in the practical application of masking
agents in bottling operations and should therefore be kept low or
avoided.
In DE-C-33 41 121, par~ffin oil emulsions and waxes are
described, fatty acid esters being used as emulsifiers. In order
to improve the coating properties and the processability, sodium
polyacrylate and morpholine fatty acid salt are added.
Paraffins, however, as short-chain oils, exhibit only a slight
water resistance and, moreover, give the film a tacky appearance.
The long-chain, higher melting waxes, on the other hand, cover
NY2-36092 . 1
21~1175
only inadequately and, due to the detachment of film particles,
cause an undesirable foam in the washing solution, which deposits
on the glass surface of the container and interferes with the
washing process.
The present invention makes available a coating
material, which fulfills all the requirements named above and
avoids the disadvantages of the methods known from the state of
the art.
Ob~ect of the Invention
An object of the present invention is a coating
material for glass surfaces for application on the worn parts of
a hollow glass container having traces of wear. The coating
material, moreover, can be used to increase the smoothness and to
cover traces of wear on flat glass products.
SummarY of the Invention
As ~lm-forming component, the inventive coating_
material contains monocarboxylic acid esters and dicarboxylic
acid esters with a total of up to 40 carbon atoms in the
molecule. For this purpose, ester oils with a total number of
10-32 carbon atoms and especially 12 to 24 and with a melting
point below the processing temperature, are preferred.
NY2-36092.1 6
215117j
Examples of ~lm-forming components are ester oils,
such as ethylhexyl ethylhe~noate~ isopropyl myristate, butyl
stearate, butyl laurate, diethylhexyl adipate or ethylhexyl
palmitate.
In addition, the oils may contain up to 10% and
preferably up to 5% of long-chain alkyl-modi~ed siloxanes of the
following formula
ICH3 IH3 jH3
Rl- SiO- SiO- Si-Rl
C`H3 l2 CH3
- -m - -n
whereln
Rl and R2 are CH3 or a C8 to C24 alkyl group and at least two R1
or R2 groups in a molecule are long-chain alkyl groups,
m is 1 to 200, and
n is 0 to 50.
For dispersing the ~lm-forming components, known
nonionic emulsifiers, such as fatty alcohol ethoxylates, sorbitol
ethoxylate fatty acid esters, polygycerol fatty acid esters,
methyl glucoside fatty acid esters, methyl glucoside ethoxylate
fatty acid esters, glycerol ethoxylate fatty acid esters or alkyl
polyglucosides (cetyl alcohol and glucosides) are used as self-
emulsifying O/W base.
~2-36092.1
21S117S
To adjust the consiætency to the desired value,
thickeners, such as polyacrylates or cellulose ethers
(hydroxypropyl cellulose) can be added.
To prevent any attack by microorganisms, the use of
preservatives, such as conventional commercial formaldehyde-
releasing materials, is advantageous.
The inventive coating material is used as an aqueous
emulsion, which preferably has the following composition:
) 1 to 40~ by weight of one or several of the film-
forming components as described
herein;
b) 0.5 to 12~ by weight of a nonionic emulsifier;
c) O to S~ by weight of a thickener;
d) O to 2~ by weight of a preservative; and
e) 41 to 98.5~ by weight of water.
In bottling plants, the coating material can be applied
on the surface of hollow glass containers using various methods.
For example, the inventive formulation can be applied by means of
a sprayer or also with the help of a fabric, felt or sponge, etc.
in the form of a ~lm on the glass surface.
~2-36092 1 8
215117S
In this connection, it is advantageous for the film-
forming ester oil to be in liquid form, in order to ensure
uniform coating of the traces of wear. Preferably, therefore,
ester oils are used, the melting points of which are below the
processing temperature.
The temperature of the glass surface for this purpose
is between 0 and 50C.
Particularly advantageous is the application of the
inventive coating materials on worn hollow glass containers in
bottling plants by means of injection spraying equipment, such as
that used in marking systems for packaging. For this purpose,
the electronic control of these systems must be modi~ed, so that
the speci~c requirements for covering wear zones are fulfilled.
Ideally, the spray is applied selectively only in the nom; n~l
rubbing zones of the hollow glass containers.
The covering effect is shown on hollow glass
containers, which are at room temperature and dry during the
application, as well as on wet and cold bottles. The e~ect does
not vary over a period of several weeks, even upon storage in a
refrigerator or a refrigerated counter. The material, color and
glue of the label are also not a~ected. The coating material is
removed completely in the bottle-washing step and causes no
problems in the alkaline washing solution.
NY2-36092.1
2151175
The inventive, film-forming components are approved as
emollients in cosmetic preparations and are toxicologically safe.
The following examples are listed for the purpose of
explaining the invention and not for any limitation.
The components were mixed with water; stable stock
emulsions with an active ingredient content of 60~ were prepared
u~ing a homogenizer. These stock solutions were then diluted to
an active ingredient content of 5 to 10~ before use. This
coating material was then sprayed on worn-out, water-filled
Steinie bottles, which were closed o~ with crown corks and had
previously been kept for at least 12 hours at 2C in the
refrigerator. During this spraying process, the bottles clearly
showed a layer of csn~n~ed water. The coating material was
evaluated on the basis of its covering property with respect to
the traces of wear, on the basis of its water resistance after
being rinsed with water and on the basis of the feel of the
bottles. The evaluation was based on a system of 6 grades, 1
being chosen for very good and 6 for inadequate. For statistical
reasons, six bottles were evaluated in each case and the results
are shown in the Table below.
NY2-36092 . 1
2151175
Active Ingredient Emulsi- Coverage Handle Water
~cation Resistance
Ethylhexyl isonanoate A 4 2 2-3
Ethylhexyl B 4 2 2-3
ethylhexanoate
Hexyl laurate B 3 2 2
Isopropyl stearate A 1 2 2
Isopropyl myristate A 1 1-2 1-2
Isocetyl palmitate A 1 2 2
Butyl stearate C 2 3 3
Cetyl octanoate A 1-2 2 2-3
Comparison:
Capryl~capric
triglyceride A 4 3-4 2-3
A = ethoxylated glycerin oleate (such as TAGAT~ 0, Th.
Goldschmidt AG)
B = aqueous dispersion of alkyl polyglycosides based on C12/C14
alcohols
C = Cl6/Cl8 glucoside / Cl6/C18 alcohol --
~Y2-36092.1 11
