Flat glass panel and method and system for the production thereof

Abstract

The non-tempered and enameled annealed flat glass panel comprises: - a non-tempered annealed glass panel having a first and a second main side (2a, 2b), - a sintered enamel arranged on the first main side (2a) in a predetermined pattern.

Description

Flat glass panel, its manufacturing process and system [1] FIELD OF THE INVENTION [2] The present invention relates to flat glass panels, their manufacturing methods and systems. [3] TECHNOLOGICAL BACKGROUND [4] More specifically, the invention relates to a method of manufacturing an enamelled flat glass panel. [5] More specifically, the invention relates to flat glass panels, such as for example used in construction, interior decoration and / or furnishing. [6] WO 2012 / 172,269 describes, for example, a process in which an enamel paste is deposited by screen printing on an initial glass panel (with the interposition of a pigment). Then, the system comprising the enamel glass panel and the enamel paste is heated to 655 °C. This heating step is part of tempering the glass. This produces enamelled tempered glass. This is the current state of the art. [7] This process is very suitable for manufacturing enamelled tempered glass of standard dimensions in large series. [8] There is an increasing demand in the market for small series. The small series requested are increasingly varied in size, numerous, and limited in quantity. There is therefore an industrial challenge in responding effectively to such demand. In addition, not all glass processors or other glass consumers (such as shower screen manufacturers, for example) are necessarily equipped with screen printing capabilities, whereas they may, on the contrary, be equipped with cutting, shaping and / or tempering capabilities. [9] Therefore, to manufacture a small series, or even to manufacture an individual panel of custom dimensions with the above process, it is necessary to cut the initial panel to the required dimensions before screen printing. In addition, the industrial screen printing stage is not always suitable for processing individual panels of variable shapes. Also, such a process presents a logistical challenge to ship each of the manufactured products to its final recipient. In the end, the production time is long, because it is necessary to transmit the dimensions of the desired product to the manufacturer upstream of production, and there is necessarily a delay in putting the product into production. As a result, it is difficult for manufacturers to cope with this increased demand for small series with custom dimensions. [9a] Document US 2021 / 309,564 is placed in the field of manufacturing ophthalmic lenses, which is a field distant from the present invention.

[0010] The invention thus aims to industrialize the production of enameled flat glass panels for small series or the need for diffuse sales.

[0011] SUMMARY OF THE INVENTION

[0012] Thus, the invention relates to a method of manufacturing an enamelled flat glass panel for use in construction, interior decoration and / or furnishing, comprising: - an initial annealed, non-tempered flat glass panel is provided comprising first and second parallel main faces, the initial flat glass panel being made of a glass material characterized by a glass transition temperature, - an enamel paste is applied in a predetermined pattern to the first parallel main face, the enamel paste being made of an enamel material, - global heating is applied to a temperature lower than the glass transition temperature, then localized, to the enamel paste, while maintaining the initial flat glass panel at a temperature lower than the glass transition temperature.

[0013] Thanks to these provisions, the annealed (non-tempered) and enamelled flat glass panel at the end of the process remains cuttable. It is therefore possible to transport a large quantity of standard annealed and enamelled flat glass panels to an end user, who can then use them for cutting and shaping on site to the desired dimensions.

[0014] Depending on different aspects, it is possible to provide one and / or the other of the provisions below.

[0015] According to one embodiment, said localized heating is applied with a LASER transmitter emitting a LASER beam directed towards and focused on the predetermined pattern.

[0016] According to one embodiment, said overall heating is applied inside a tempering furnace configured to maintain the initial glass panel at a temperature below the transition temperature of the glass.

[0017] According to one embodiment, the previous steps are repeated to enamel the second main face.

[0018] According to one embodiment, after applying global and localized heating, the initial glass panel is cooled, then cut and / or drilled.

[0019] According to one embodiment, after applying global and localized heating, the initial glass panel is cooled and, if necessary, after cutting and / or drilling, tempered.

[0020] According to another aspect, the invention relates to a non-tempered and enameled annealed flat glass panel comprising: - a non-tempered annealed flat glass panel comprising a first and a second parallel main face, - a sintered enamel arranged on the first parallel main face according to a predetermined pattern.

[0021] According to one embodiment, the panel further comprises at least one of the following characteristics: - the non-tempered annealed glass panel comprises at least part of a shaped edge, - the non-tempered annealed glass panel is drilled and / or machined, - the non-tempered annealed glass panel is enamelled on its two main faces.

[0022] According to another aspect, the invention relates to a system for manufacturing an enameled flat glass panel comprising: - a docking station for an annealed initial glass panel comprising a first and a second main face, the initial glass panel being made of a glass material characterized by a glass transition temperature, the first main face carrying an enamel paste in a predetermined pattern, the enamel paste being made of an enamel material, - a heating device adapted to apply overall heating to a temperature below the glass transition temperature, and localized heating to the enamel paste, while maintaining the initial glass panel at a temperature below the glass transition temperature.

[0023] According to one embodiment, the heating device comprises a tempering furnace configured to maintain the initial glass panel at a temperature below the transition temperature of the glass and a LASER transmitter adapted to emit a LASER beam directed towards and focused on the predetermined pattern.

[0024] According to one embodiment, the LASER emitter is arranged outside the tempering furnace, the manufacturing system comprising a conveying system adapted to move the initial glass panel from a heating section of the tempering furnace to the LASER emitter and then from the LASER emitter to a cooling section of the tempering furnace, in particular in opposite directions.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the invention will be described below with reference to the drawings, briefly described below:

[0027] Figure 1 shows a side view of an initial flat glass panel.

[0028] Figure 2 is a side view of a screen printing installation.

[0029] Figure 3 is a side view of a heating installation.

[0030] Figure 4 is a view similar to Figure 1 for an enameled flat glass panel according to a first embodiment of the invention.

[0031] Figure 5 is a view similar to Figure 1 for an enameled flat glass panel according to a second embodiment of the invention.

[0032] Figure 6 is a view similar to Figure 1 for another enameled flat glass panel according to the invention

[0033] Figure 7 is a photo showing the result of cutting on a prototype.

[0034] In the drawings, like references designate identical or similar objects.

[0035] DETAILED DESCRIPTION

[0036] Figure 1 schematically represents an initial flat glass panel 1. This glass could be, for example, but not limited to, soda-lime glass with a clear or extra-clear tint or else tinted throughout, with or without acid-etched treatment on one of the faces. This initial flat glass panel 1 is said to be "annealed". In this document, "annealed" refers to a material designated by the English technical term "annealed". This material can be "annealed" without having been subjected to several firing steps, contrary to what the term "annealed" might suggest. In particular, the initial glass panel 1 is not tempered. The state of the material can, for example, be visualized by a light polarization test such as, for example, a Babinet test. The material constituting the initial flat glass panel 1 is a glass which has a glass transition temperature.The "transition temperature" of a material is defined as the temperature at which a mechanically elastic behavior changes to a more plastic domain at higher temperatures. Until this transition temperature has been exceeded, the mechanical stresses in the glass remain temporary: they therefore disappear once the glass has returned to room temperature. The initial flat glass panel is translucent. The initial flat glass panel comprises two main faces 2a, 2b, flat, parallel, separated by a small thickness compared to the other dimensions of the initial flat glass panel. The thickness is typically less than a factor of at least 10 than the other dimensions of the initial flat glass panel, typically by a factor of at least 100. The thickness is, for example, 2 to 19 millimeters (mm) or typically 3 to 12 mm. As such, it should be noted that the figures are not necessarily to scale.

[0037] The first main face 2a is likely to receive a decoration by screen printing.

[0038] During a decoration step, as shown in Figure 2, the initial glass panel 1 is placed in a screen printing installation for the application of enamels. Enamels are surface coatings containing minerals and oxides. Among the minerals constituting the enamel, silica may be mentioned. Among the minerals, feldspar and / or kaolin may also be used. Among the oxides, alkali oxides, in particular sodium or potassium, calcium oxide, alumina, or even lead oxides and / or borax may be mentioned. The enamel may also include one or more transition metal oxides used as pigments. For the application of enamels, an enamel paste is used comprising the constituents presented above constituting the enamel, as well as an organic solvent medium conferring viscosity and facilitating its application.In particular, the enamel paste used is standard and does not include a polymer-based binder whose function is to crosslink under the effect of heat to improve the setting of the enamel. The enamel paste 3 is characterized by a sintering temperature, for example greater than 550°C, or even greater than 600°C, at which the enamel vitrifies. An enamel paste 3 is thus applied to the first main flat face 2a. According to one example, the enamel paste 3 is applied directly in contact with the first main flat face 2a, without the interposition of an intermediate layer. At this stage, the enamel paste 3 is opaque but may become slightly translucent once fired.

[0039] The enamel paste 3 is applied to the main flat face 2a in a predetermined pattern. For the sake of clarity, it is described here that the main face receiving the enamel paste is the main flat face 2a. For example, the initial flat glass panel 1 is held horizontal with the main face 2a facing upwards, and the enamel paste 3 is applied thereon by any technique such as, for example (but not limited to), a screen, a roller in digital printing, a curtain, or by spraying. For example, the initial flat glass panel 1 is shown with the main face 2b supported by a support 4. Referring to this orientation, the main face 2b may be called the "lower face" and the main face 2a the "upper face", but this designation does not predict the subsequent orientation of the panel 1 during the subsequent stages of manufacture and then its use. The deposition of the enamel paste 3 according to the predetermined pattern is implemented by a screen printing step in a screen printing machine 5. This application of enamel paste 3 may include a subsequent drying step, aimed at evaporating the solvents from the enamel paste 3 once it has been applied to the initial flat glass panel 1. The drying may involve a temperature higher than ambient temperature, for example lower than 300°C, in particular lower than 200°C, or even 150°C, or even at 100°C. Alternatively, the enamel paste 3 can be applied by spraying a solvent-free enamel powder.

[0040] At the end of this step, an initial flat glass panel 1 is available bearing, on a main face 2a, an enamel paste 3. The initial flat glass panel 1 is moved towards the subsequent steps of the process using a conveyor system applied against its lower face 2b. Preferably, any contact with the upper face 2a which bears the enamel paste 3 which is still fragile at this stage (despite the summary drying step described above) is then avoided.

[0041] The system comprising the initial flat glass panel 1 and the enamel paste 3 is placed in a heating device 6. The heating device 6 is adapted to place the enamel paste 3 at a higher temperature, while maintaining the initial glass panel 1 at a temperature below its glass transition temperature, for a sufficient time, without inducing permanent stresses therein making subsequent use of the panel difficult or even impossible, and in particular without softening it. For example, the initial glass panel 1 is maintained at a temperature below 485°C, below 480°C, or even below 470°C. According to an exemplary embodiment, the heating device 6 comprises a localized heating device 7. The localized heating device 7 is adapted to apply heating in a localized manner to the enamel paste 3.According to one example, the localized heating device 7 comprises a LASER emitter 8 adapted to emit a LASER beam towards and focused towards the enamel paste 3, and therefore according to the predetermined pattern. The LASER is for example a CO2 LASER. The LASER is for example a near infrared LASER emitting at a wavelength between 800 nanometers (nm) and 1100 nm. The LASER is for example a continuous LASER. Alternatively, a pulsed LASER delivering pulses of 50 to 250 nanoseconds (ns) at a frequency between 10 and 1000 kiloHertz (kHz), typically between 10 and 150 kHz, can be used with scanning of the enameled surface. The localized heating device 7 applies localized heating to the predetermined pattern that is greater than the heating applied to the initial glass panel 1. This makes it possible to apply localized heat to the enamel paste layer 3 at surface temperatures higher than the sintering temperature of the enamel, without causing the glass panel to exceed its transition temperature. During sintering, the constituent oxides of the enamel paste will melt and firmly bond to each other, trapping the mineral grains. According to one embodiment, an overall preheating is applied to the system consisting of the initial flat glass panel and the enamel paste 3 before implementing the localized heating.Just as can be seen in the field of welding, this overall preheating allows a certain thermal level to be reached to initiate the baking process of the enamel paste. but also maintain it. Thus, less LASER energy will be required for baking the enamel, which avoids surface thermal shocks or the initiation of cracking of the glass. In addition, the LASER scanning frequency will better correspond to industrial production rates. Otherwise, too slow a LASER scanning would make the cost of this production not necessarily economically viable. According to an exemplary embodiment, as shown in Figure 3, the initial glass panel 1 carrying the enamel paste 3 is received in a docking station 12. For example, it rests by its main face 2b on a support 9 in the heating device 6, and the main face 2a is arranged upwards. The localized heating device 7 faces the main face 2a, and localized heating can be applied to the enamel paste pattern 3. The heating is carried out in an air atmosphere.

[0042] Sintered enamel can be identified by a marking test. This is because the porosity of the enamel has decreased after sintering. When you apply a marker to a sintered enamel, the porosity is low enough that the marker's ink will not be retained on the surface of the sintered enamel.

[0043] As presented above, the heating device 6 also comprises a global heating device 10 adapted to heat the initial flat glass panel 1. For example, a non-localized heating device is used, making it possible to place a macroscopic zone of the enclosure of the heating device 6 at a given temperature. In particular, the global heating device 10 is adapted to heat the initial glass panel 1 to a temperature lower than the glass transition temperature of the initial glass panel 1, for example between 250°C and 400°C.

[0044] Thus, the heating device 6 makes it possible to place the system comprising the initial glass panel 1 and the enamel paste 3 in a temperature field such that the temperature applied to the initial glass panel 1 is lower than the glass transition temperature and the temperature applied to the enamel paste 3 is high enough for a sufficient time to induce sintering of the enamel paste 3.

[0045] This step also makes it easier to attach the enamel to the initial glass panel 1.

[0046] If necessary, the global heating device 10 is first used, so as to preheat the system comprising the initial glass panel 1 and the enamel paste 3 to a temperature below the glass transition temperature, but close to it, then localized heating is applied to the enamel paste to locally increase the temperature of the enamel paste 3 without significantly heating the initial flat glass panel 1. Maintaining the glass at temperature during the localized heating phase may require Initially overheat the glass panel slightly, typically one or a few tens of degrees above the holding temperature shown above, in order to take into account cooling during subsequent conveyance to the localized heating station and / or during the application of localized heating.

[0047] Then, cooling is applied to the system comprising the initial glass panel and the enamel. Cooling can be achieved simply by leaving the system in the open air, or by implementing active cooling. Since the glass panel has remained in the elastic phase, cooling can be done in a controlled manner, but fairly quickly without fear of inducing damaging permanent stresses in the glass panel.

[0048] According to an exemplary embodiment, a tempering furnace is used as a global heating device 10, configured to apply a temperature lower than the temperature used for tempering the glass. This will also save the need for a dedicated installation. This embodiment is notably shown in Figure 3. A tempering furnace typically comprises a heating section 13 then a cooling section 14 arranged downstream of the heating section 13 in the direction of treatment of the glass panel. Indeed, a tempering furnace can (with some adaptations) preheat the glass to temperatures lower than the transition temperature of the glass and this in a homogeneous manner. In addition, a tempering furnace is provided to cool the glass quickly at industrial rates.According to one embodiment (not shown), the localized heating device 7 is arranged in the heating section 13, or between the heating section 13 and the cooling section 14. Alternatively, as shown, the localized heating device 7 is arranged outside the tempering furnace. This variant makes it possible to use the tempering furnace both for the present invention, and for a conventional glass tempering process, while minimizing modifications to the existing industrial process. In fact, the localized heating device 7 can be arranged after the tempering / cooling sections, which sections will be stopped during the conveying period towards the outlet. According to this embodiment, the initial glass panel 1 carrying the enamel paste 3 is first placed in the heating section 13 for preheating.Then, it is conveyed to the localized heating device 7 through the inactive cooling section 14. Once the enamel has been thus treated, the initial glass panel 1 is moved in the opposite direction in the cooling section 14 to be cooled to a temperature close to room temperature. Then, the panel is moved again in the first direction, towards the outlet, the localized heating device 7 being inactive, for lifting. Cooling. is not necessarily implemented in a cooling tunnel with a very precise temperature profile.

[0049] At the end of this step, a system is obtained comprising a flat annealed (i.e. not tempered) glass panel and a sintered enamel arranged in a predetermined pattern. Since it has been treated at low temperatures, the glass constituting the panel at this stage is indistinguishable from the glass before the process is implemented.

[0050] The system thus obtained can be used as is. We then obtain a panel of annealed (not tempered) and enameled flat glass as shown in Figure 4. The sintered enamel thus obtained has the same characteristics of mechanical strength or adhesion to the glass as in the case of overall tempering in the previous state of the art. It also has a smooth surface condition with a completely acceptable level of roughness.

[0051] The resulting system therefore does not include any additional coating that covers the enamel.

[0052] If necessary, the enameled glass panel thus obtained (at the end of any of the preceding steps) is treated to enamel the main face 2b. For example, the enameled glass panel is turned over, its main face 2b now facing upwards, and the process described above is applied once again to the other main face. The pattern applied to the second main face 2b may be different from that applied to the first main face 2a. Any contact of the transport system with the vitreous enamel on the first main face does not negatively impact the latter. The heat treatments presented above do not negatively impact the glass panel or the vitreous enamel on the first main face. This produces a flat glass panel annealed (not tempered) and enameled on both faces as shown in Figure 5.

[0053] Alternatively, it is possible to process the system thus obtained (enameled on one or both main faces) by removing material from the initial flat glass panel 1. The initial glass panel 1, which has not been previously tempered, can thus be cut and then shaped in order to resize it as desired. The resulting panel therefore has a shaped edge, at least partially. Alternatively or in addition, one or more localized through-holes or machining operations can be implemented in the initial glass panel 1. This produces an annealed and enamelled flat glass panel as shown in Figure 6 for the first embodiment. Figure 7 is a photo of a prototype. The cutting can be done either through the enamelled pattern (as shown) or not.

[0054] It is therefore possible to produce standard-sized annealed and enameled flat glass panels in large quantities using an industrial process, and to apply dimensional, geometric or mechanical customization as late as possible in the manufacturing process, and therefore as close as possible to the final requirement. Logistics are thus simplified. If necessary, the initial glass panel 1 enameled, in particular on one side only, after having been resized and / or machined or drilled, is tempered. If necessary, the tempering furnace presented above is used, but configured for tempering. This step involves heating the initial glass panel 1 to a temperature above its glass transition temperature, for example above 640°C, or even 670°C, then rapidly cooling it. A tempered and enameled flat glass panel is then obtained as already shown in Figures 4 or 6, respectively.

[0055] The tempered and enamelled flat glass panel thus personalized can be used for example (without limitation) as a shower panel, furniture panel, door panel, window panel or facade panel.

[0056] Example

[0057] Flat glass samples were used. The samples have dimensions of 100x100x2.8 millimeters (mm).

[0058] An enamel paste is applied to a first flat face of the glass samples by screen printing with a 77-thread-per-centimeter mesh screen. Enamels referenced VV 42-43-11-NA and VV 42-43-13-NB from Pemco on the filing date of this patent application are used. The VV 42-43-11-NA enamel is a borosilicate-based enamel comprising inorganic pigments, typically metal oxides. The product sheet indicates a temperature of 640 to 720 °C for the tempering cycle, a temperature of 590 to 620 °C for the annealing cycle, and a coefficient of thermal expansion of 70-80.10' 7 °C' 1 . VV 42-43-13-NB enamel is a bismuth-based enamel comprising inorganic pigments, typically metal oxides. The product sheet indicates a temperature of 640 to 720 °C for the quenching cycle, a temperature of 580 to 620 °C for the annealing cycle, and a coefficient of thermal expansion of 70-80.10' 7 °C' 1.

[0059] The enamel paste is deposited on glass samples, then dried at a temperature below 200 °C to remove the solvents. Enameling is carried out on static samples. Preheating of the flat glass samples carrying the enamel paste between 400 °C and 500 °C was implemented. A CO2 LASER beam is directed towards the enamel paste. The wavelength of the LASER beam is 10.6 pm. The CO2 LASER beam has an average power of 88 to 92 kW, a pulse frequency of 33 kHz at 37 kHz, and a pulse duration of 300 nanoseconds (ns). The pulse energy is 2.7 mJ. The peak power is 9 kW. The beam aperture is 20 mm. The focal length is 300 mm. The LASER beam is emitted with a focal plane 15 millimeters (mm) from the surface to be treated. The resolution is 0.45 lines per millimeter. The scanning speed was chosen between 800 and 1,800 millimeters per second (mm / s), notably between 900 and 1,200 mm / s. The power density is 1.2 to 1.4 kW / cm 2 .

[0060] Notably, the VV 42-43-11-NA coated samples were preheated to 500 °C and were scanned at a speed between 900 and 1200 mm / s.

[0061] These parameters made it possible to obtain sintering speeds of 4 to 5 seconds for the treated samples, i.e. a sintering speed of around 10 minutes per square meter of panel.

[0062] The samples produced were subject to the following observations: - the samples produced have similar characteristics, - no effect of the treatment on the glass panel is observed, - no boundary effect between the area covered by the enamel paste and that not covered by the enamel paste is observed, - samples can be cut like annealed glass, - the adhesion of the enamel to the glass panel is confirmed following a scratch test.

[0063] The parameters implemented can be adapted according to the glass or enamel used.

[0064] Reference 1: Initial flat glass panel 2a, 2b: Main faces 3: enamel paste 4: support 5: screen printing machine 6: heating device 7: localized heating device 8: LASER transmitter 9 support 10: global heating device : docking station : heating section : cooling section

Claims

CLAIMS

1. A method of manufacturing an enamelled flat glass panel for use in construction, interior decoration and / or furnishing, comprising: - an initial non-tempered annealed flat glass panel (1) is provided comprising first and second parallel main faces (2a, 2b), the initial flat glass panel (1) being made of a glass material characterized by a glass transition temperature, - an enamel paste (3) is applied in a predetermined pattern to the first parallel main face (2a), the enamel paste (3) being made of an enamel material, - global heating is applied to a temperature lower than the transition temperature of the glass, then localized, to the enamel paste (3), while maintaining the initial flat glass panel (1) at a temperature lower than the transition temperature of the glass.

2. A method of manufacturing an enamelled flat glass panel according to claim 1, wherein said localized heating is applied with a LASER emitter (8) emitting a LASER beam directed towards and focused on the predetermined pattern.

3. Method of manufacturing an enamelled flat glass panel according to one of claims 1 to 2, in which said overall heating is applied inside a tempering furnace configured to maintain the initial glass panel (1) at a temperature below the transition temperature of the glass.

4. Method of manufacturing an enamelled flat glass panel according to one of claims 1 to 3, in which the preceding steps are repeated to enamel the second main face (2b).

5. Method for manufacturing an enamelled flat glass panel according to one of claims 1 to 4, in which, after having applied global and localized heating, the initial glass panel (1) is cooled, then cut and / or pierced.

6. Method for manufacturing an enamelled flat glass panel according to one of claims 1 to 5, in which, after having applied global and localized heating, the initial glass panel (1) is cooled and, if necessary, after having cut and / or drilled.

7. A non-tempered, enamelled, annealed flat glass panel comprising: - a non-tempered annealed flat glass panel comprising a first and a second main faces (2a, 2b) parallel, - a sintered enamel arranged on the first main face (2a) parallel according to a predetermined pattern.

8. An enameled non-tempered annealed flat glass panel according to claim 7, further comprising at least one of the following features: - the non-tempered annealed glass panel comprises at least part of a shaped edge, - the non-tempered annealed glass panel is drilled and / or machined, - the non-tempered annealed glass panel is enamelled on its two main faces (2a, 2b).

9. System for manufacturing an enamelled flat glass panel comprising: - a docking station for an annealed initial glass panel (1) comprising a first and a second main face (2a, 2b), the initial glass panel being made of a glass material characterized by a glass transition temperature, the first main face (2a) carrying an enamel paste (3) in a predetermined pattern, the enamel paste being made of an enamel material, - a heating device (6) adapted to apply overall heating to a temperature lower than the glass transition temperature, and localized to the enamel paste (3), while maintaining the initial glass panel (1) at a temperature lower than the glass transition temperature.

10. A system for manufacturing an annealed and enameled flat glass panel according to claim 9, wherein the heating device (6) comprises a tempering furnace set to maintain the initial glass panel (1) at a temperature below the transition temperature of the glass and a LASER emitter (8) adapted to emit a LASER beam directed towards and focused on the predetermined pattern.

11. Manufacturing system according to claim 10, wherein the LASER emitter (8) is arranged outside the tempering furnace, the manufacturing system comprising a conveying system adapted to move the initial glass panel (1) from a heating section (13) of the tempering furnace to the LASER emitter (8) and then from the LASER emitter (8) to a cooling section (14) of the tempering furnace, in particular in opposite directions.

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