PROCESS FOR OBTAINING A DECORATIVE MIRROR

Abstract

A process for obtaining a decorative mirror includes reflective regions forming a pattern and non-reflective regions, the process including providing a sheet of soda-lime-silica glass coated with a reflective coating on the entirety of one of the faces thereof, then applying a composition including a phosphate salt to the reflective coating, solely in application regions, the application regions being intended to become the non-reflective regions, then tempering the glass sheet, in which the glass sheet is subjected to a temperature of at least 550° C., causing the reflective coating to dissolve in the application regions so as to form the non-reflective regions in which the glass sheet is not coated.

Claims

1. A process for obtaining a decorative mirror comprising reflective regions forming a pattern and non-reflective regions, said process comprising: providing a sheet of soda-lime-silica glass coated with a reflective coating on the entirety of one of the faces thereof, then applying a composition comprising a phosphate salt to said reflective coating, solely in application regions, said application regions being intended to become the non-reflective regions, then tempering said glass sheet, in which said glass sheet is subjected to a temperature of at least 550° C., causing the reflective coating to dissolve in the application regions so as to form said non-reflective regions in which the glass sheet is not coated.

2. The process as claimed in claim 1, wherein the reflective coating comprises at least one functional layer that is a metal layer or a layer of a metal nitride.

3. The process as claimed in claim 2, wherein the metal layer is based on chromium or niobium.

4. The process as claimed in claim 2, wherein the layer of a metal nitride is a layer of niobium nitride.

5. The process as claimed in claim 2, wherein the reflective coating is a stack of thin layers, in which stack the or each functional layer is flanked by two protective layers made of oxides, nitrides or oxynitrides.

6. The process as claimed in claim 1, wherein the reflective coating is an alternating stack of thin high-refractive-index dielectric layers and of thin low-refractive-index dielectric layers.

7. The process as claimed in claim 1, wherein the reflective coating is deposited by cathode sputtering.

8. The process as claimed in claim 1, wherein the phosphate salt is an ammonium phosphate or an alkali-metal phosphate.

9. The process as claimed in claim 1, wherein the composition comprising the phosphate salt comprises a solvent and a resin.

10. The process as claimed in claim 1, wherein the applying is carried out by screen-printing.

11. The process as claimed in claim 1, furthermore comprising, after the tempering, a cleaning step.

12. A decorative mirror comprising reflective regions forming a pattern and non-reflective regions, said mirror being obtained using the process as claimed in claim 1, said mirror comprising a sheet of soda-lime-silica glass that is not coated in said non-reflective regions and that is coated with a reflective coating in said reflective regions.

13. The decorative mirror as claimed in claim 12, wherein a light reflectance of the reflective regions, on the side of the reflective coating, is at least 25%.

14. The decorative mirror as claimed in claim 13, wherein the light reflectance in the reflective regions, on the side of the reflective coating, is at least 40%.

15. A partition, interior door, shower screen, bath screen, store fixture or fitting, salon fixture or fitting, room fixture or fitting, showroom fixture or fitting, facade cladding or part of an electrical appliance, especially an oven door, comprising a decorative mirror as claimed in claim 12.

16. An intermediate product intended to form a decorative mirror comprising reflective regions forming a pattern and non-reflective regions, said intermediate product comprising a sheet of soda-lime-silica glass coated on the entirety of one of the faces thereof with a reflective coating, said reflective coating being coated in certain regions with a composition comprising a phosphate salt.

17. The process as claimed in claim 5, wherein the two protective layers are made of oxides, nitrides or oxynitrides of silicon or aluminum.

18. The process as claimed in claim 8, wherein the phosphate salt is a sodium phosphate.

19. The process as claimed in claim 9, wherein the solvent is an organic solvent.

20. The decorative mirror as claimed in claim 14, wherein the light reflectance in the reflective regions, on the side of the reflective coating, is at least 50%.

Description

EXAMPLE 1

[0041] A sheet of clear soda-lime-silica glass was obtained by cutting a glass substrate coated beforehand by cathode sputtering with a reflective stack, sold under the reference SGG Mirastar.

[0042] The reflective stack used consisted in a succession, starting from the glass, of a first layer of silicon nitride, of a layer of chromium, then of a second layer of silicon nitride.

[0043] To this coated glass sheet was applied, by screen-printing, a composition comprising sodium phosphate and a resin, in decorative geometric patterns. The application allowed a temporary layer having a wet thickness (before drying) of about 25 μm to be obtained.

[0044] The glass sheet thus coated was then subjected to a thermal tempering treatment involving heating to 650-680° C. for 180 seconds in a tempering furnace.

[0045] After tempering, the regions of application of the phosphate salt were covered with a gel that could be removed by simply wiping with a damp cloth. In these regions, the reflective coating completely disappeared, causing bare, and therefore transparent, glass to appear. In the adjacent regions in contrast, which were not covered with the phosphate salt, the reflective coating remained present.

[0046] The obtained mirror therefore comprised reflective regions and non-reflective regions forming patterns, the separation between the regions furthermore being very clear. The light reflectance coating-side of the reflective regions was 60%, and the light transmittance 3%.

[0047] EXAMPLE 2

[0048] Example 2 differs from Example 1 only in the nature of the reflective stack, here the stack sold by the Applicant under the reference SGG Cool-Lite ST108. This stack consists of a succession, starting from a clear glass substrate, of a first layer of silicon nitride, of a layer of niobium, then of a second layer of silicon nitride.

[0049] Results of the same nature as those of Example 1 were obtained. The light reflectance coating-side of the reflective regions was 44%, and the light transmittance 9%.

EXAMPLE 3

[0050] Example 3 also differs from Example 1 in the nature of the reflective stack, in the present case the stack sold by the Applicant under the reference Cool-Lite ST Bright Silver.

[0051] In this example, the reflective coating is an alternating stack of thin high-refractive-index dielectric layers and of thin low-refractive-index dielectric layers. More precisely, this stack comprises a layer of titanium oxide (high index), then a layer of silica (low index) and lastly a layer based on titanium oxide (high index).

[0052] Results of the same nature as those of Example 1 were obtained. The light reflectance coating-side of the reflective regions was 31%, and the light transmittance 67%.