Method for Partially Coating a Surface of an Object

Abstract

The invention relates to a method for partially coating a surface of an object, comprising the following steps: (a) optional hydrophobization of the surface of the object; (b) partial application of (b1) a liquid and subsequent application of a powderous or granular substance or (b2) a solution or suspension of said powderous or granular substance in a liquid; (c) drying the surface to form spatially-delimited salt or powder crusts; (d) coating the surface with at least one layer of a metal or a metal compound; and (e) removing the salt or powder crusts that have been produced. The invention also relates to products that have been produced according to the claimed method.

Claims

1. A process for partially coating a surface of an object, comprising the following steps: (a) optionally hydrophobizing the surface of the object; (b) partially applying (b1) a liquid followed by applying a powdery or granular substance; or (b2) a solution or suspension of the powdery or granular substance in a liquid; (c) drying the surface to form spatially delimited salt or powder crusts; (d) coating the surface with at least one layer of a metal or metal compound; (e) removing the salt or powder crusts that have been produced.

2. The process according to claim 1, characterized in that said object is a decorative element made of glass or ceramic.

3. The process according to claim 2, characterized in that said decorative element is preferably a polished facetted glass element.

4. The process according to at least one of the preceding claims, characterized in that said liquid is selected from water, alcohols and oils, or any mixture thereof.

5. The process according to at least one of the preceding claims, characterized in that said powdery or granular substance has a grain size of 0.01-1.0 mm.

6. The process according to at least one of the preceding claims, characterized in that said powdery or granular substance is selected from common salt, polyvinyl alcohol granules, sugar, flour, gypsum, icing sugar.

7. The process according to at least one of the preceding claims, characterized in that said applying (b) of the liquid or solution is effected through one or more spraying nozzles.

8. The process according to at least one of the preceding claims, characterized in that said drying (c) of the surface is effected at temperatures above 40 C.

9. The process according to at least one of the preceding claims, characterized in that said coating of the surface (d) is effected by physical vapor deposition.

10. The process according to at least one of the preceding claims, characterized in that said removing of the salt or powder crusts that have been produced (e) is effected by washing with water.

11. A product obtainable by a process according to at least one of claims 1 to 10.

1. A process for partially coating a surface of an object, comprising the following steps: (a) optionally hydrophobizing the surface of the object; (b) partially applying (b1) a liquid followed by applying a powdery or granular substance; or (b2) a solution or suspension of the powdery or granular substance in a liquid; (c) drying the surface to form spatially delimited salt or powder crusts; (d) coating the surface with at least one layer of a metal or metal compound; (e) removing the salt or powder crusts that have been produced.

2. The process according to claim 1, characterized in that said object is a decorative element made of glass or ceramic.

3. The process according to claim 2, characterized in that said decorative element is a polished facetted glass element.

4. The process according to claim 1, characterized in that said liquid is selected from water, alcohols and oils, or any mixture thereof.

5. The process according to claim 1, characterized in that said powdery or granular substance has a grain size of 0.01-1.0 mm.

6. The process according to claim 1, characterized in that said powdery or granular substance is selected from common salt, polyvinyl alcohol granules, sugar, flour, gypsum, icing sugar.

7. The process according to preceding claim 1, characterized in that said applying (b) of the liquid or solution is effected through one or more spraying nozzles.

8. The process according to claim 1, characterized in that said drying (c) of the surface is effected at temperatures above 40 C.

9. The process according to claim 1, characterized in that said coating of the surface (d) is effected by physical vapor deposition.

10. The process according to claim 1, characterized in that said removing of the salt or powder crusts that have been produced (e) is effected by washing with water.

11. A product obtainable by a process according to at claim 1.

Description

EXAMPLES

[0038] Preliminary Experiments

Example 1

NaCl

[0039] Facetted glass chatons were wetted with H.sub.2O mist (0.5 mm nozzle) and subsequently scattered with NaCl granules. The thus obtained partially masked substrate was vapor-deposited with Cr. The masking showed good adhesion even on the facets.

[0040] Even in vacuum coating processes with a higher temperature evolution, neither evaporation nor decomposition of the NaCl could be observed. The optical appearance of the masking could be controlled and adapted by the amount of the H.sub.2O mist and by the particle size of the salt granules (grain sizes of about 0.2 to 0.5 mm can be employed well).

Example 2

BN Suspension in H.SUB.2.O/CH.SUB.3.COOH/propanol

[0041] The suspension was sprayed through a 0.75 mm nozzle onto facetted chatons. Al/SiO.sub.2 and Cr/SiO.sub.2/Zr/ZrN/Fe.sub.2O.sub.3 were used as coatings. The masking showed a very good adhesion to the facets and could be removed very well with lukewarm water; very uniform distribution of the droplets; uniform optical appearance on the facets.

Example 3

Mowiol Granules, Fine

[0042] Facetted glass chatons were wetted with H.sub.2O mist (0.5 mm nozzle) and subsequently scattered with Mowiol granules (fine). Al/SiO.sub.2 was used as the coating. The masking showed excellent adhesion to the lateral facets. However, in order to remove, i.e., washing off, the masking, the partially coated substrates had to be soaked in water for an extended period of time, which is disadvantageous for industrial applications.

Example 4

Mowiol Granules, Unsifted

[0043] Facetted glass chatons were wetted with H.sub.2O mist (0.5 mm nozzle) and subsequently scattered with Mowiol granules (unsifted). Al/SiO.sub.2 was used as the coating. As in Example 3, the masking showed excellent adhesion to the lateral facets. However, as in Example 3, the masking could be successfully removed only after soaking in water for an extended period of time.

Example 5

Mowiol Granules, Coarse

[0044] Facetted glass chatons were wetted with H.sub.2O mist (0.5 mm nozzle) and subsequently scattered with Mowiol granules (coarse). Al/SiO.sub.2 was used as the coating. The coarse granules adhered poorly to the facets wetted with spraying mist. As in Examples 3 and 4, the masking could be successfully removed only after soaking in water for an extended period of time.

Example 6

Mowiol Solution in Water

[0045] Facetted glass chatons were sprayed with a solution of 20% by weight Mowiol in water (0.75 mm nozzle). Zr/ZrO.sub.2 was used as the coating. The application of the masking proved simple; however, the distribution of droplets is non-uniform.

Example 7

Chalk Paint Suspension in Water

[0046] Facetted glass chatons were sprayed with a commercially available suspension of chalk paint in water (0.75 mm nozzle). Al/SiO.sub.2 and Zr/ZrN were used as coatings. The application of the masking proved easy, and the masking adhered well to the lateral facets; uniform distribution of the droplets; uniform optical appearance of the patina effect.

Example 8

Moltofill Suspension in Water

[0047] Facetted glass chatons were sprayed with a suspension of 80 g of Moltofill in 100 ml of water (0.75 mm nozzle). Zr/ZrN and Al/SiO.sub.2 were used as coatings. The application of the masking proved simple, and the masking also adhered very well to the lateral facets. The distribution of the droplets was uniform, and a uniform optical appearance of the patina effect was obtained.

Example 9

Chalk Paint

[0048] Facetted glass chatons were wetted with a commercially available chalk paint suspension through a screen (mesh size 710 m; ISO 3310-1) using a brush. Zr/ZrN was used as a coating. The application of the masking was easy; however, the distribution of the droplets was non-uniform, and a non-uniform optical appearance of the patina effect was obtained.

Example 10

Gypsum Suspension in Water

[0049] Facetted glass chatons were wetted with a suspension of 100 g of gypsum in 100 g of water by a spray-on method using a paintbrush. Al/SiO.sub.2 was used as the coating. The application of the masking is simple; however, the masking adheres worse to glass as compared to the other maskings. When the masking is removed (mechanical rubbing), the heavy evolution of dust is disadvantageous. However, the masking can be readily washed off with water.

Example 11

Sugar

[0050] Facetted glass chatons were wetted with a spraying mist of water (0.5 mm nozzle). Subsequently, sugar crystals were applied through a screen. Al/SiO.sub.2 was used as the coating. The application of the masking is simple, and also the masking adheres very well to the lateral facets. However, the masking discolors from caramelization of the sugar during the PVD process. The sugar masking can be washed off readily, and the discoloration also disappears by the washing.

Example 12

Iicing Sugar

[0051] Facetted glass chatons were wetted with a spraying mist of water (0.5 mm nozzle). Subsequently, icing sugar was applied through a screen. Al/SiO.sub.2 was used as the coating. The application of the masking is simple, and also the masking adheres very well to the lateral facets. As in Example 14, the masking discolors from caramelization of the sugar during the PVD process. The sugar masking can be washed off readily after the PVD process; the discoloration is no longer visible after the washing.

Example 13

NaCl Solution in Water

[0052] Facetted glass chatons were wetted with a saturated solution of NaCl in H.sub.2O (concentration about 360 g/l at 25 C.; 0.5 mm nozzle). The thus obtained partially masked substrate was coated with Cr and Zr/ZrO.sub.2. The masking showed good adhesion also to the facets; however, the layer thickness of the masking material was not sufficient.

Example 14

Sugar

[0053] Facetted glass chatons were wetted with a spraying mist of a sugar solution (0.5 mm nozzle). Al/SiO.sub.2 was used as the coating. The application of the masking is simple, and also the masking adheres very well to the lateral facets. As in Examples 11/12, the masking discolors from caramelization of the sugar during the PVD process. The sugar masking can be washed off readily; the discoloration disappears by the washing.

Technical Process

[0054] Because of the preliminary experiments, the method according to Example 1 was selected for a technical fabrication of the glass objects with a patina effect.

[0055] The technical process for masking was performed with the above described masking plant. NaCl was used as the masking material, and differently facetted glass chatons were used as the substrate. A number of different coatings was applied by the above described PVD methods. After the coating process, the maskings were removed with lukewarm water. FIGS. 1-3 show different glass substrates that have been coated by the method according to the invention. The partially masked substrates show a very beautiful patina effect, which cannot be achieved by the usual masking methods. Surprisingly, the partially masked substrates are as stable as completely coated substrates in all tests usual in the jewelry industry (sea water test, sweat test, UV test, perfume test).