SK77095A3 - Coating matter for glass surfaces and its use - Google Patents

Abstract

A coating material (I) for covering abrasion marks on glass surfaces contains, as the film-forming component, mono- or di-carboxylic acid esters with a total of up to 40 C atoms (II). Also claimed is a process for covering scratches on glass, esp. returnable glass containers, by coating with (I) at 0-50 degrees C.

Description

Coating compound for glass surfaces and its use

Technical field

The invention relates to a coating material for glass surfaces to cover traces of wear, such as scratches and scratches on the glass surface, in particular reusable container glass.

BACKGROUND OF THE INVENTION

Glass containers filled with, for example, beverages such as milk, beer, fruit juice, mineral water or lemonade are largely returnable containers. After collection, they are returned to the manufacturer after use and refilled. Bottles are damaged during shipping and filling by touching the bottles or touching metal surfaces. These wear marks should be overlapped. To this end, several requirements must be met:

- good coverage of scratched areas

- Water resistance after only a short time

- Applicability also for wet bottles

- non-sticky coating with pleasant feel

- no impact on labels, inks and label adhesives

- perfect film washability and desirable behavior in an alkaline washing bath

- toxicological safety.

Films must have good hiding power for traces of wear while being water resistant. Since glass containers are often stored in refrigerators and refrigerated counters, the coatings must be resistant to condensation water. The film coating must also function on wet and cold bottles. The film must not be sticky because stickyness would be unacceptable to the customer and, moreover, the coating would become contaminated by the application of dust. The thermal curing of the film is not feasible due to the high filling speed, and the filling material may be affected. Ensure that the film can be washed with an alkaline water bath.

Although methods have already been proposed for covering traces of wear which are not removable by an alkaline washing bath. However, they are not advantageous because the glass containers are refilled, transported, emptied, collected and washed repeatedly. The permanent film thereby easily damages itself and then exhibits unwanted traces of wear. During the washing process, the quality of the coating deteriorates, so that it becomes, for example, opaque in the milk. In addition, layer thicknesses of up to 50 µm are desirable in such a case; in terms of the cost of covering traces of wear is unacceptable.

The literature already describes in detail the current state of solution of this problem. U.S. Patent 4,237,334 discloses a formulation consisting of a high molecular weight polysiloxane resin having methyl, phenyl and alkoxy groups on silicon atoms, dissolved in hydrocarbon solvents such as toluene and xylene. This method is inconclusive with regard to hygienic and toxicological considerations.

The use of low molecular weight, and thus ethanol-soluble, polyorganosiloxanes is described in U.S. Pat. No. 3,574,673. The adhesion to the glass surface is improved by the introduction of monofunctional groups. A disadvantage of this method is the use of flammable solvents. Due to the use of aminofunctional groups, a marked yellow coloration is observed upon storage of the treated bottles.

The use of modified polyorganoxiloxanes containing functional groups such as amino, mercapto and / or trialkoxysilyl groups to improve adherence to glass surfaces is described in U.S. Pat. No. 4,222,554.

- 3 loxanes cure using a tin-based catalyst which is toxicologically doubtful.

U.S. Patent 4,662,221 discloses polysiloxanes in combination with cationic and nonionic surfactants. A process based on polysiloxanes that can be applied in volatile polysiloxanes as solvents to the surface of bottles is disclosed in EP-A-395077.

EP-A-464779 discloses triglyceride emulsions which can be prepared using nonionic emulsifiers and additional paraffin and silicone oil components.

In all of these methods known in the art, considerable amounts of polysiloxanes are generally used. However, these substances are degraded to the volatile, circular siloxane monomers D3, D4 and D5 under the washing bath conditions. However, this phenomenon is undesirable in filling plants and especially in breweries as foam stability problems may occur. The use of polysiloxanes is therefore critical for the practical use of coating agents in fillers and is therefore difficult to maintain or avoid.

DE-C-33 41 121 describes paraffin oil emulsions and waxes, fatty acid esters being used as emulsifiers. Sodium polyacrylate and morpholine fatty acid salts are added to improve the coating and processability characteristics. However, paraffins, as short-chain oils, show only a low water resistance and impart a sticky effect to the film. On the other hand, higher-melting waxes with long chain cover imperfectly and form in the wash bath by dissolving the film particles an undesirable foam which is deposited on the surface of the glass containers and interferes with the washing process.

It is therefore an object of the present invention to provide a coating material. which meets all the requirements and does not have the above-described shortcomings of the prior art.

SUMMARY OF THE INVENTION

Coating material for covering the traces of glass wear. . According to the invention, it comprises a monocarboxylic or dicarboxylic acid ester having a total of up to 40 carbon atoms per molecule as the film-forming component. Preferred according to the invention are ester oils having a total carbon number of 10 to 32, in particular 12 to 24, and having a melting point lower than the working temperature.

Examples of the film-forming component are ester oils such as ethylhexylethyl hexanoate, isopropyl myristate, butyl stearate, butyl laurate, diethylhexyl adipate or ethylhexyl palmitate.

The oils may additionally contain up to 10%, preferably 5%, alkyl-modified siloxanes of the general formula

'CH3 I ΌΗ3 1 1 You are about - 1 1 You are about - 1 1 CH3 m 1 3 ²

where it means

R 2 and R 2 are methyl groups or C 8 -C 24 alkyl groups and at least two R or R groups in the molecule are long chain alkyl, m 1 to 200 and n 0 to 50,

Non-ionic emulsifiers, known per se, such as, for example, fatty alcohol ethoxylates, fatty acid sorbitan ethoxylate, polyglycerol fatty acid ester, fatty acid methyl glucoside ethoxylate, fatty acid glycerol ethoxylate glyceride or alkyl polyether glucoside (alkylpolyglucose glucoside) are used to disperse the film-forming component. oil / water bases.

Thickening agents such as polyacrylates or cellulose ethers (hydroxypropylcellulose) may be added to adjust the desired processing consistency. Preservatives such as, for example, formaldehyde-based commercial agents are preferred to prevent infestation by microorganisms.

The coating compositions according to the invention are used in the form of aqueous suspensions, preferably with the following composition by weight: a / 1.0 to 40.0% of at least one film-forming agent according to the invention, b / 0.5 to 12.0% of a nonionic emulsifier, c / 0 to 5.0% thickener; d / 0 to 2.0% preservative; e / 41.0 to 98.5% water.

In the fillers, various methods can be used to apply to the surface of hollow glass containers. The coating composition according to the invention can be applied using a spray apparatus or even with a cloth, felt or sponge or in the form of a film on a glass surface.

It is preferred that the film-forming ester oil component be in liquid form and that uniform wear coverage is achieved. Preferably, therefore, ester oils are used whose freezing point is below the processing temperature. The glass surface temperature is 0 to 50 ° C.

It is particularly advantageous to apply the coating composition according to the invention to worn hollow glass containers in filling stations by means of injection spraying devices which are used in packaging marking systems. The electronic control of these systems is modified to meet specific requirements to cover worn areas, ideally spraying only on areas where the hollow glass containers are abraded.

The effect of the coating appears both on hollow glass containers which are at room temperature during application and are dry, as well as on wet and cold bottles. The effect does not change during

- a 6-week interval, even when stored in a refrigerator or in a refrigerated counter. Label material, label colors and label size are not adversely affected. The coating material in the bottle washing step is without. · Removes and does not cause any problems in the alkaline washing bath. The film-forming components according to the invention are permissible as emollients in cosmetics and are toxicologically harmless.

The invention is illustrated in more detail by the following non-limiting example.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

The ingredients are mixed with water. Using a homogenizer, a stable master emulsion is prepared with an active ingredient content of 60%. In use, the master emulsion is then diluted to a content of 5 to 10%. This coating material is sprayed onto the bottles. filled with water and sealed with a cork crown cap, which have been stored in the refrigerator for at least 12 hours. The bottles already show significant dew condensation. The coating composition is evaluated by means of coating characteristics relating to wear tracks and to the water resistance after rinsing with water and the feel of the bottles. Six marks are used for the evaluation, which means 1 very good and 6 very bad qualities. 6 bottles are rated for statistical reasons. The test results are shown in Table I.

Table I

Active substance emulsification Opacity Ohmat Water resistance etylhexylizononanoát A 4 2 2-3 etylhexyletylhexanoát B 4 2 2-3 laurate E 3 2 2 isopropyl stearate A 1 2 2

- 7 Table I - continued

Active substance emulsions Gaci coverage feel of Water resistance isopropyl A 1 1 -2 1 -2 izoacetylpalmitát A 1 2 2 palmitate C 2 3 3 cetyl A 1 -2 2 2 Comparison of triglyceride- Ryl / capric acid A 4 3-4 3-4

A = ethoxylated glycerol oleate (e.g. TAGAT ® 0, Th. Goldschmidt AG /

B = aqueous dispersion of alcohol-based alkyl polyglycosides

C = g / C ₁ gglucoside / 0 µg / C ₁ alcohol

Industrial usability

A glass-coating composition comprising, as a film-forming component, a monocarboxylic or dicarboxylic acid ester having up to 40 carbon atoms per molecule and an emulsion f comprising at least one film-forming agent, non-ionic emulsifiers or thickeners, preservatives and water.

Claims (7)

PATENT CLAIMS A coating composition for glass surfaces, characterized in that it contains, as a film-forming component, an ester of a monocarboxylic or dicarboxylic acid having a total of up to 40 carbon atoms per molecule. Glass coating according to claim 1, characterized in that it contains, as a film-forming component, an ester oil having a total number of carbon atoms of 10 to 32, in particular 12 to 24, with a melting point lower than the process temperature. The glass-surface coating composition according to claim 1 or 2, characterized in that the carboxylic acid fraction of the film-forming component contains 3 to 28 carbon atoms and the alcohol fraction contains 4 to 24 carbon atoms. The glass-coating composition according to claims 1 to 3, characterized in that the film-forming component is isopropyl myristate. 5. A coating composition according to claim 1, comprising up to 10% by weight of alkyl modified siloxanes of the formula: ~ CH3 1 CH3 and R1 - 1 You are about - I 1 You are about - T 1 CH3 m 1 R 2 where it means 1 2 R and R are methyl or C 8 -C 24 alkyl and at least two R or R groups in the moiety - 9 lekule means a long chain alkyl group, m 1 to 200 and n 0 to 50. Coating composition in the form of an emulsion, characterized in that it comprises a / 1.0 to 40.0% by weight of at least one film-forming substance according to claims 1 to 5, b / 0.5 to 12% of a non-ionic emulsifier, c / 0 to 5.0% thickener, d / 0-2.0% preservative, e / 41.0-98.5% water. 7. A method of masking wear marks of a glass surface, characterized in that a coating composition is applied to the glass surface at a temperature of from about 50 DEG C. to the outer surface of the hollow reusable glass containers according to claim 1.