WO2024188831A1 - Method and system for manufacturing a coated laminated glass panel - Google Patents

Abstract

A method for manufacturing a coated laminated glass panel comprises: - providing a laminated glass panel to be coated, which comprises two glass sheets (11a, 11b) joined by means of a polymeric interlayer material (12); - providing a flowable decorative material; - forming a decorative coating layer (13) by applying the decorative material to the top face (11a1) of the laminated glass panel to be coated; - drying the decorative coating layer (13) by heating by means of a drying device, of which a setpoint temperature at the level of the polymeric interlayer material (12) is greater than or equal to 60°C and less than 100°C, the drying device (112) comprising a laser heating device (108) suitable for emitting a beam in the direction of the decorative coating layer (13).

Description

Method and system for manufacturing a coated laminated glass panel

FIELD OF THE INVENTION

The present invention relates to a method and system for manufacturing a laminated glass panel coated with a decorative layer.

More specifically, the invention relates to a method of manufacturing a laminated glass panel coated with a decorative layer such as a reflective layer or a lacquer.

TECHNOLOGICAL BACKGROUND

In the field of decorative coated glass, two types of decorative layers are particularly appreciated: light-reflecting layers so that the glass has a mirror-like appearance and "lacquer" type decorative layers, formed from a resin-rich paint and having a so-called taut appearance.

Thus, a mirror classically consists of a monolithic glass with a thickness typically between 2 and 8 mm covered with a layer of silver which gives it its reflective power. The thickness of the silver layer is typically of the order of a few tens of nanometers and its surface mass is generally at least 700 mg/m ²

To improve the chemical and mechanical resistance of the silver layer, it can be covered with a protective varnish, most often with a thickness of the order of several micrometers.

Lacquered glass, for its part, classically consists of monolithic glass, with a thickness typically between 2 and 12 mm, covered with a layer of decorative paint of the “lacquer” type - most often with a thickness of the order of several micrometers - which gives it the desired aesthetic appearance and which has satisfactory chemical and mechanical resistance characteristics.

These processes for coating monolithic glass, although satisfactory from an aesthetic point of view, do not provide sufficient mechanical resistance properties for certain applications, particularly in the construction sector.

The safety of coated monolithic glass obtained by conventional processes can be improved by means of an anti-shatter adhesive film placed on the back of the glass, which retains the pieces of glass in the event of breakage, the mechanical performance of such a structure remaining limited since the risk of breakage is not or is little modified by the presence of the anti-shatter film.

In the field of glass, it is also known to temper glass to improve its mechanical properties. Tempered glass cannot be re-cut after tempering. If we were to consider a decorative coating of tempered glass, we would therefore be limited by the shape of the tempered glass piece before coating. It is understandable that this choice is very limiting for applications in the building such as cupboard doors, tables, wall surfaces, which are often made to measure.

In the field of glass, it is still known to laminate glass to improve its mechanical properties. Laminated glass is an assembly of glass sheets and plastic interlayers, particularly in the form of FDM, generally made of polyvinyl butyral (PVB) or ethylene vinyl acetate (EVA). The presence of the interlayer material increases the mechanical resistance to breakage and prevents the formation of splinters.

Various processes have been described which make it possible to obtain laminated glass mirrors or lacquered laminated glass, the decorative layer being intercalated, or equivalently placed in a sandwich, between two sheets of glass.

In particular, document GB2248160 describes a method for obtaining a laminated glass mirror in which: a reflective coating is deposited on a first sheet of glass, then a second sheet of glass is glued to the first sheet using an adhesive such as polyvinyl butyral (PVB), the reflective coating being interposed between the two sheets of glass.

Based on such a process, it is not possible to simply reverse the order of the components to position the reflective coating on an external face of the final product. Indeed, on the one hand, the reflective coating (or any other decorative coating) thus positioned would then be mechanically damaged by the calendering or transport rollers used to assemble the two sheets, and on the other hand, the autoclaving phase on an industrial scale presents a risk of deterioration of the coatings of the layers of a given panel and of bonding of the glass panels to each other.

In addition, the optical defects of the mirror formed by the method of GB2248160 are determined by those of the glass layer on which the reflective coating is deposited.

Similarly, W02009/081077 describes a lacquered laminated glass in which a layer of lacquer is sandwiched between two sheets of glass, the whole being subjected to a heat treatment under pressure to ensure the bond between the sheets of glass. Such a process requires the use of a lacquer that is resistant to heat treatment under pressure, which limits the choice of colours. In addition, the good adhesion of the PVB can be affected, particularly in the case of varnishes with aqueous solvents. This presents future risks of delamination of the product.

Document FR 3 106 526 describes a method for manufacturing a coated laminated glass panel. After application, the lacquer is baked and dried by raising the ambient temperature to 120°C in a maximum of 6 minutes, then lowered to ambient temperature in less than two minutes.

The invention thus aims to propose a method of coating a laminated glass panel with a decorative layer making it possible to obtain an energy-efficient glass panel coated laminate having impact and/or perforation resistance and chip retention properties at least as good as those obtained by the methods of the prior art and improved optical and decorative properties compared to the methods of the prior art.

SUMMARY OF THE INVENTION

Thus, the invention relates to a method of manufacturing a coated laminated glass panel comprising:

- a laminated glass panel to be coated is provided comprising at least two glass sheets and in which at least two successive glass sheets are assembled by means of a polymer interlayer material forming after assembly an interlayer, the laminated glass panel to be coated having at least one upper face to be coated;

- a flowing decorative material is provided;

- at least one decorative coating layer is formed by applying the decorative material in a fluid state to the upper face of the laminated glass panel to be coated;

- the decorative coating layer is dried by heating the laminated glass panel thus covered using a drying device whose set temperature at the polymer interlayer material is greater than or equal to 60°C and less than 100°C, the drying device comprising at least one LASER heating device adapted to emit a beam in the direction of the decorative coating layer.

Thanks to these provisions, it is possible to industrially manufacture coated laminated glass panels without bubbling or yellowing of the interlayer material from already assembled laminated glass panels. In addition, the energy requirement is reduced by the implementation of localized LASER heating.

The coating process also makes it possible to manufacture a mirror-type glass panel and a lacquered glass panel with a reduced carbon footprint over the product's lifetime. Indeed, laminated glass is around five times stronger and around a hundred times more rigid than monolithic glass. It can therefore be expected that the renewal of mirrors/lacquered glass in laminated glass will be less frequent than that of the prior art lacquered mirrors/glass.

According to one embodiment of the method for manufacturing a coated laminated glass panel, the polymer interlayer material is selected from polyvinyl butyral, ethylene vinyl acetate, an ionoplast polymer, thermoplastic polyurethane and a casting resin.

These different polymer interlayer materials have different characteristics in terms of refractive index, mechanical resistance and hydrophobicity, which makes it possible to modulate the optical and/or mechanical properties and/or humidity resistance of the coated laminated glass panel depending on its future use.

According to one embodiment of the method of coating a laminated glass panel, at least one decorative coating layer consists of either a layer of material reflective and one or more layers of protective varnish or one or more layers of lacquer and optionally one or more layers of protective varnish.

This arrangement makes it possible, from the same generic process, to form mirror-type laminated glass panels and colored laminated glass panels using a lacquer, these two types of laminated glass panels not having the same uses.

According to one embodiment of the method for coating a laminated glass panel, a chemical hardener or a crosslinking catalyst is incorporated into the fluid decorative material in a ratio P cata between the mass of chemical hardener or crosslinking catalyst and the mass of decorative material in the determined fluid state; the ratio P cata of the mass of chemical hardener or crosslinking catalyst and the mass of decorative material in the fluid state is greater than 0.1%.

Such a proportion of chemical hardener makes it possible to limit the maximum surface temperature reached by the glass panel, so that the interlayer polymer material does not bubble or yellow and that the crosslinking of the decorative coating layer is satisfactory with a drying time at this maximum surface temperature which is limited and particularly acceptable in an industrial process.

According to one embodiment of the method for coating a laminated glass panel, the chemical hardener or the crosslinking catalyst is chosen from acid catalysts and optionally from hydrofluoric acid, phosphoric acid and paratoluenesulfonic acid.

These chemical hardeners and crosslinking catalysts have the advantage of allowing a sufficient lowering of the crosslinking temperature to avoid bubbling problems. According to one embodiment, the drying device further comprises at least one heating device adapted to carry out convective and radiative heating.

In one embodiment, a conveyor system moves the coated laminated glass panel into the drying device between an inlet and an outlet defining a length of the furnace, and the LASER heating device is adapted to emit the beam toward a beam interception location with the decorative coating layer offset from the inlet by at least one tenth, in particular at least one fifth, of the length of the furnace.

According to one embodiment, said heating device adapted to carry out convective and radiative heating is arranged upstream of the LASER heating device.

According to one embodiment, said set temperature (Tint) is less than 80°C.

According to one embodiment, the heating system is configured to generate at the decorative coating layer a surface energy of between 400 and 1500 kJ/m ² of panel, in particular between 450 and 850 kJ/m ² , in particular between 500 and 800 kJ/m ² , between 550 and 750 kJ/m ² , or even between 600 and 700 kJ/m ² . This range makes it possible to exceed, at the decorative coating layer, an average temperature threshold allowing the crosslinking of the decorative coating layer, without burning effect and without adverse effect on the underlying layer of polymer interlayer material.

According to one embodiment, an emitter of the LASER heating device emits a LASER beam at a power of less than 100 W, in particular less than 50 W, less than 40 W, less than 35 W, or even less than 30 W. This power range can make it possible to obtain the desired heating effect, without a burning effect, for limited energy consumption.

According to one embodiment, the LASER heating device is configured to have an inter-line gap of between 10 microns and 100 microns, in particular between 25 and 85 microns, or even between 35 and 75 microns. This range of inter-line gaps can make it possible to provide heat in a sufficiently homogeneous manner at the decorative coating layer. According to one embodiment, the LASER heating device is configured to have a defocus at the decorative coating layer of between 5 mm and 50 mm, in particular between 10 mm and 40 mm, or even between 15 mm and 30 mm. This defocus range makes it possible to distribute heat in a sufficiently homogeneous manner at the decorative coating layer.

According to one embodiment, the LASER heating device is configured to move the LASER beam at the decorative coating layer at a speed of between 0.2 m/s and 10 m/s, in particular between 1 m/s and 5 m/s, or even between 2 m/s and 3 m/s. This speed range makes it possible to distribute the heat sufficiently homogeneously at the decorative coating layer.

According to one embodiment, the LASER heating device is configured to generate a number of passes of the LASER beam at each point of the decorative coating layer between 1 and 200, in particular between 2 and 50, between 5 and 20, or even between 10 and 15. This range of numbers of passes makes it possible to maintain the local temperature level above a threshold value for a time greater than a predetermined threshold duration.

According to one embodiment, the LASER heating device comprises a plurality of LASER diodes, in particular between 100 and 2000 LASER diodes.

According to one embodiment, a laminated glass panel to be coated is provided comprising at least one layer of silver having said upper face to be coated.

According to one embodiment, said LASER heating device is adapted to emit said beam in the near infrared towards the decorative coating layer. Indeed, the glass panel is transparent to such radiation, which makes it possible to reduce the heating of the glass panel itself.

According to another aspect, the invention relates to a system for manufacturing a coated laminated glass panel comprising:

- a laminated glass panel to be coated comprising at least two sheets of glass and in in which at least two successive glass sheets are assembled by means of a polymer interlayer material forming after assembly an interlayer, the laminated glass panel to be coated having at least one upper face to be coated;

- a fluid decorative material;

- an application device adapted to apply decorative material in a fluid state to the upper face of the laminated glass panel to be coated to form at least one decorative coating layer;

- a drying device adapted to dry the decorative coating layer by heating the laminated glass panel thus covered with a set temperature at the polymer interlayer material greater than or equal to 60°C and less than 100°C, the drying device comprising at least one LASER heating device adapted to emit a beam towards the decorative coating layer.

According to one embodiment, the heating system is configured to generate at the decorative coating layer a surface energy of between 400 and 1500 kJ/m ² of panel, in particular between 450 and 850 kJ/m ² , in particular between 500 and 800 kJ/m ² , between 550 and 750 kJ/m ² , or even between 600 and 700 kJ/m ² .

According to one embodiment, an emitter of the LASER heating device is adapted to emit a LASER beam at a power of less than 100 W, in particular less than 50 W, less than 40 W, less than 35 W, or even less than 30 W. This power range can make it possible to obtain the desired heating effect, without a burning effect, for limited energy consumption.

According to one embodiment, the LASER heating device is configured to have an inter-line gap of between 10 microns and 100 microns, in particular between 25 and 85 microns, or even between 35 and 75 microns.

According to one embodiment, the LASER heating device is configured to have a defocusing at the decorative coating layer of between 5 mm and 50 mm, in particular between 10 mm and 40 mm, or even between 15 mm and 30 mm.

According to one embodiment, the LASER heating device is configured to move the LASER beam at the decorative coating layer at a speed of between 0.2 m/s and 10 m/s, in particular between 1 m/s and 5 m/s, or even between 2 m/s and 3 m/s.

According to one embodiment, the LASER heating device is configured to generate a number of passages of the LASER beam at each point of the decorative coating layer of between 1 and 200, in particular between 2 and 50, between 5 and 20, or even between 10 and 15.

According to one embodiment, the LASER heating device comprises a plurality of LASER diodes, in particular between 100 and 2000 LASER diodes.

According to one embodiment, said LASER heating device is adapted to emit said beam in the near infrared towards the decorative coating layer. BRIEF DESCRIPTION OF THE DRAWINGS

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

[Fig. 1] represents a side view of a laminated glass panel coated according to the invention. [Fig. 2] is a schematic side sectional view of an installation according to a first embodiment.

DETAILED DESCRIPTION

The laminated glass panel to be coated comprises at least two glass sheets, among which an upper glass sheet 11a and a lower glass sheet 11b are defined. The terms “lower” and “upper” are used with reference to the orientation of the panel in the furnace, regardless of the previous or subsequent orientation of the panel.

Any type of flat glass (or possibly curved by the bending processes known to those skilled in the art, when it comes to coating curved surfaces) can be used for each of the glass sheets.

Each sheet of glass is by definition monolithic.

In one embodiment, one or more of the at least two glass sheets are produced by the float process to obtain a flat and smooth glass sheet with very good precision, or by drawing or rolling processes.

In one embodiment, at least one or all of the glass sheets are tempered.

In one embodiment, the upper glass sheet 11a, one face of which will ultimately be coated with at least one decorative coating layer 13 at the end of the method according to the invention, is not made of tempered glass. Tempered glass may indeed have microdeformations likely to alter the decorative qualities of the coating, in particular in the case where this coating is obtained or contains a layer obtained by a silvering process.

In the case where none of the glass sheets are tempered, the laminated glass panel has the advantage of being able to be re-cut to the desired dimensions and/or for downgrading the edges if their characteristics are not satisfactory at the end of the process.

There are no limitations on the dimensions of the at least two sheets of glass, apart from those related to the manufacturing process of each of the sheets of glass and the assembly process. In particular, the thickness of a sheet of glass may be between 2 and 12 mm, or even more, depending on the final use of the coated laminated glass panel. For example, a thickness of 2 mm to 6 mm, or even 2 mm to 5 mm or 2 mm to 4 mm or even 2 mm to 3 mm, and in particular equal to 2 mm, 3 mm, 4 mm, 5 mm or 6 mm, for one or more of the at least two sheets of glass may be considered.

The at least two sheets of glass may have two by two identical or different thicknesses and/or compositions. The at least two glass sheets are superimposed on each other in a stacking direction (Z'Z) and assembled two-by-two by means of at least one polymer interlayer material, such that after assembly, at least one interlayer 12 is intercalated (or equivalently sandwiched) between at least two successive glass sheets, as shown in FIG. 1.

Regardless of the number of superimposed glass sheets (two or more), the laminated glass panel to be coated therefore comprises at least: an upper glass sheet l ia whose face external to the assembly is intended to receive the coating and constitutes the so-called upper face l iai of the laminated glass panel to be coated, and a lower glass sheet 11b consisting of the glass sheet furthest from the upper glass sheet l ia in the stacking direction (Z’Z) and whose face external to the assembly constitutes the lower face l lbl of the laminated glass panel to be coated.

The polymeric interlayer material may comprise one or more polymers.

In particular, the polymer interlayer material may be polyvinyl butyral (PVB). PVB has the following advantages, among others:

- PVB has a refractive index close to that of soda-lime-silica glass commonly used for making glazing, so that the interlayer sheet is invisible or almost invisible.

- PVB also absorbs shocks very effectively and retains glass fragments in the event of glass breakage.

It may also be ethylene vinyl acetate (EVA). The hydrophobic properties of LEVA are particularly interesting if the coated glass panel is intended to be installed in a humid environment or outdoors: the risk of delamination over time due to humidity is reduced by the use of LEVA for the interlayer 12 of polymer material.

It is also possible to use a polymer interlayer material called "ionoplast", in particular of the SentryGlass® type, which makes it possible to form laminated glass that does not exhibit any bubbling or yellowing defects even when exposed to high temperatures, up to 80°C, during their implementation.

In another embodiment, the interlayer material may still be thermoplastic polyurethane (also called TPU or “Thermoplastic PolyUrethan”) or a casting resin (or equivalently “CIP” (“Cast In Place”) resin).

The interlayer material can be tinted before assembly, so as to give a particular coloring to the laminated glass panel in association with the decorative coating once the panel is coated. Once the laminated glass panel to be coated is supplied, a decorative material in a fluid state is provided.

The decorative material in the fluid state may in particular be in the liquid state with a more or less significant viscosity, this viscosity being adapted to allow the deposition of a layer of decorative material on the laminated glass panel, for example by means of a roller or a spray gun or even a curtain machine.

The decorative material can be lacquer.

A lacquer is a non-transparent coating, which may be translucent, but is generally opaque, and which comprises, before drying, a solvent in which at least one pigment and at least one polymeric resin are dissolved, as well as optionally mineral fillers.

Pigments function to provide the desired color and opacity.

The polymer resin acts as a binder: it is used to bind the pigments and, where applicable, the mineral fillers after drying.

The binder is preferably based on acrylic resin. The binder can also be based on alkyd resin or a polyurethane binder.

For example, the decorative material can be a lacquer such as Glassolux (produced by Fenzi ®) or equivalent.

The lacquer can be applied, for example, using a curtain machine, a roller or a gun in one or more passes.

The choice of the number of passes for depositing the lacquer, and consequently the number of layers of lacquer, can be determined in particular according to the desired opacity and/or the desired mechanical resistance.

The thickness of the lacquer deposited can be between 10 and 100 micrometers.

The decorative material can also be a reflective material after drying.

The laminated glass panel may for example comprise a decorative material, for example comprising silver, which may among other things be deposited by oxidation-reduction by bringing into contact an ammoniacal silver nitrate solution with a reducing agent solution. Then, the decorative coating layer is applied on the silver layer to improve the chemical and mechanical resistance of the silver layer.

The decorative material is therefore supplied in a fluid state, insofar as it includes in particular one or more solvents.

The fluid decorative material is deposited directly on an external face of the upper glass sheet 11a so as to form a decorative coating layer and this decorative coating layer is dried.

The application of the decorative layer on an external face of the laminated glass already formed is a mandatory step of the process according to the invention, despite its difficulty of implementation because it presents several advantages. Firstly, it allows the appearance of a laminated glass panel manufactured beforehand to be modified, possibly on another production line, and the decorative coating to be chosen subsequently, possibly on a case-by-case basis.

Secondly, the superposition of at least two sheets of glass under the decorative coating layer makes it possible to improve the optical quality of the coated laminated glass, particularly in the case where the aim is to form a laminated glass mirror. Indeed, each sheet of glass has flatness defects with a pitch of the order of a meter and optical defects with a pitch of the order of 1 cm to 10 cm, but which cannot all be superimposed on each other when assembling the two sheets of glass. The optical distortions of the laminated glass coated on its external face are therefore less than if the coating had been inserted between the two sheets of glass.

To overcome the technical problem of obtaining a suitably cross-linked decorative coating layer within an acceptable time for an industrial process (in particular for a continuous manufacturing process, in which the laminated glass panel to be coated is moved at constant speed on a production line), typically of the order of a few minutes or a few tens of minutes, the inventors have therefore considered using chemical hardeners or chemical catalysts.

In particular, it may be envisaged to incorporate into the decorative material in the fluid state a total proportion of one or more crosslinking catalysts and/or chemical hardeners P_cata equal to or greater than 0.1%, or even equal to or greater than 0.5% by mass, 1% by mass, 2% by mass of the decorative material in the fluid state, 2.5% by mass of the decorative material in the fluid state and optionally less than 10% by mass of the decorative material in the fluid state, or even less than 5% by mass of the decorative material in the fluid state.

According to one embodiment, a proportion of infrared radiation absorbers is also incorporated into the decorative material in the fluid state. Such absorbers have a high conversion rate of light at the wavelength to which they are dedicated into heat.

The protective varnish may be chosen, in a non-limiting manner, from: commercial anti-corrosion varnishes from suppliers such as FENZI (for example FENZI One coat LF 3 grey SG, FENZI one coat WBLF 6 varnishes), VALSPAR (for example references SK1420 or SK1440) or EUROCOATINGS (for example eurocoatings glasskin007 varnish).

In the case of a lacquer, this may be, without limitation, commercial lacquers from suppliers such as FENZI (e.g. glassolux NG lacquer), MADER (e.g. madercoat LRY168 and madercoat 572 lacquers) or VALSPAR (e.g. reference SK3875). As for the chemical hardener or crosslinking catalyst, it can be chosen depending on the flowable decorative material.

In particular, an acid catalyst such as hydrofluoric acid, phosphoric acid, paratoluenesulfonic acid, or any other transesterification catalyst can be used. The fluid decorative material in which at least one chemical hardener and/or at least one crosslinking catalyst has been incorporated is then deposited on the upper face 1 lal of the laminated glass panel to be coated so as to form at least one decorative coating layer 13. The deposition of the fluid decorative material can be carried out by means of a device for depositing a fluid material such as a curtain coater, a roller or a gun.

The thickness of the at least one decorative coating layer may be greater than 10 micrometers.

Then the decorative coating layer is dried so as to obtain its cross-linking and at least partial evaporation of the solvents.

The proportion P cata of chemical hardener or crosslinking catalyst must be chosen to allow application of the decorative coating in a fluid state and in particular during an industrial process. In particular, this proportion may be chosen to allow application of the decorative coating by means of a device such as a curtain machine.

In particular, it is not possible to increase the proportion of chemical hardener or crosslinking catalyst in an indiscriminate manner since too high a proportion causes the product to set at too low a temperature and/or too quickly. In such a case, the decorative material does not remain in a fluid state long enough to allow its application to the upper face 1 lal of the laminated glass panel to be coated.

Uncontrolled caking also leads to the obstruction of pipes or transport elements through which the decorative material must circulate.

The catalyst solidification time was assessed by observation with the naked eye in the case where the crosslinking catalyst is paratoluenesulfonic acid incorporated into the fluid decorative material is One Coat LF3 from the Fenzi brand in a proportion P cata expressed as a percentage of the mass of the fluid decorative material.

Tableau 1 : durée de prise en masse en fonction de la proportion P cata de catalyseur de réticulation The results are grouped in Table 1 below: [Table 1]

Table 1: Mass setting time as a function of the proportion P cata of crosslinking catalyst

It is found that an excessive proportion of chemical hardener or crosslinking catalyst leaves little time for further processing steps of the fluid decorative material, in particular for its application to the laminated glass panel to be coated.

It is therefore necessary to find a compromise between the proportion of chemical hardener or crosslinking catalyst, the drying temperature and the drying time.

A proportion P_cata of chemical hardener or crosslinking catalyst less than or equal to 10% by mass of the fluid decorative material, or even 5% by mass of the fluid decorative material, or even 2.5% by mass of the fluid decorative material may be suitable for implementing the method according to the first embodiment of the invention.

Figure 2 schematically represents a drying device 112 comprising an oven 101 for implementing an embodiment of the invention. The oven 101 is a continuous oven comprising an enclosure 102 and a heating system 103 adapted to place the interior of the enclosure 102 according to a given temperature profile. In particular, the heating system 103 is adapted to generate a given temperature profile in a zone of the oven in which the decorative coating layer 13 is located. Typically, the heating system is regulated so that a set temperature in the zone of the oven where the polymer interlayer material is located is between 60°C and 100°C, or even between 60°C and 80°C. The determination of this satisfactory temperature range at the level of the polymer interlayer material can be carried out in several ways. For example, a temperature measurement system is used within the oven, capable of determining the temperature at the level of the polymer interlayer material. Alternatively, a temperature measurement system is used in another location in the furnace, and the temperature at the polymer interlayer material is determined by applying a predetermined rule relating the measured temperature to the temperature at the polymer interlayer material. This predetermined rule is, for example, determined during a prior calibration step. For example, the other location in the furnace where the temperature is measured is on the surface of the laminated glass panel. During the calibration step, thermocouples are affixed to the surface of the laminated glass panel before entering the furnace and, upon exiting the furnace, it is measured or noted whether the decorative coating layer and the polymer interlayer material are in a satisfactory condition. If the polymer interlayer material is in a satisfactory condition, it means that it has not reached the temperature of 100°C or even 80°C. If the decorative coating layer is in a satisfactory condition, it has been sufficiently heated, which implies that the nearby polymer interlayer material has been heated to at least 60°C. Depending on the result of this measurement or observation, and in view of the measurements from the sensors, the temperature of the heating devices is validated, lowered or increased until a satisfactory heating profile is obtained. This gives a rule linking the temperature to the material level polymer interlayer at the measured temperature. During manufacturing, a panel is regularly instrumented to check whether the temperature measured at the thermocouples is similar to that corresponding to the calibration step and, if necessary, the temperature profile is adjusted.

According to one embodiment, the oven is a continuous oven comprising a conveying system

104 adapted to move a laminated glass panel from an entrance 105 to an exit 106. The entrance

105 can be adapted to allow a laminated glass panel to enter the enclosure. The outlet

106 may be adapted to allow a laminated glass panel to exit the enclosure. The conveying system 104 may be adapted to move the laminated glass panel continuously, in particular at a constant speed, between the inlet 105 and the outlet 106. Alternatively, the conveying system 104 may not move the laminated glass panel at a constant speed, but for example move it according to a suitable movement profile, comprising for example one or more localized slowdowns, accelerations or stops. The laminated glass panel is arranged with its lower face 1 lb 1 carried by the conveying device, and the decorative coating layer 13 remote from the conveying device.

The heating system 103 comprises for example one or more heating devices 107 adapted to carry out convective and radiative heating.

The heating system 103 also includes one or more LASER heaters 108. A LASER heater 108 includes an emitter 109 adapted to generate a LASER beam directed toward the decorative coating layer 13. The laminated glass panel is thus placed with the decorative coating layer 13 oriented toward the LASER heater 108. The LASER heater 108 can thus be arranged at the upper part of the enclosure, above the laminated glass panel. The LASER beam intercepts the laminated glass panel at a location that can be linear along a line transverse to the direction of movement of the panel in the furnace. The energy of the beam is then transformed into heat in the coating layer. The linear location can be obtained by scanning a point LASER beam along a transverse line at a predetermined speed. The LASER heating device 108 thus allows localized heating of the decorative coating layer 13 which complements the heating generated by the heating devices 107. A substantial saving of energy is achieved, since the heating is provided locally at the location where it is needed, and not to the entire volume of the laminated glass panel. In addition, the energy required for subsequent cooling of the laminated glass panel is also reduced. The wavelength of the emitted beam can for example be chosen so as to be absorbed by the coating layer. It can be located mainly in the near infrared, more particularly between 800 and 1100 nanometers (nm), for example between 800 and 1000 nanometers (nm). Moreover, the glass panel is, for its part, transparent to such radiation, so that the heat transfer towards the glass panel, and therefore to the interlayer material, is reduced.

According to one embodiment, the emitter 109 is a continuous emitter. It has an average maximum power of less than 500 Watts (W). According to one embodiment, the emitter 109 of the LASER heating device emits a LASER beam at a power of less than 100 Watts (W). This power range can make it possible to obtain the desired heating effect, without a burning effect, for limited energy consumption. According to one embodiment, the emitter 109 of the LASER heating device emits a LASER beam at a power of less than 50 W, less than 40 W, less than 35 W, or even less than 30 W. According to the embodiments, and if compatible with the embodiments presented above, the emitter 109 emits a LASER beam at a power greater than 25 W, greater than 30 W, greater than 35 W, or even greater than 40 W.

According to one embodiment, the LASER heating device 108 is configured to have an inter-line gap of between 10 microns and 100 microns. This range of inter-line gaps can make it possible to provide heat in a sufficiently homogeneous manner at the decorative coating layer 13. According to the embodiments, the inter-line gap is between 25 and 85 microns, or even between 35 and 75 microns.

According to one embodiment, the LASER heating device 108 is configured to have a defocus at the decorative coating layer 13 of between 5 millimeters (mm) and 100 mm, in particular between 5 mm and 50 mm. The defocus corresponds to the diameter of the focal spot at the decorative coating layer 13. This defocus range makes it possible to distribute the heat in a sufficiently homogeneous manner at the decorative coating layer 13. According to the embodiments, the defocus range is between 5 mm and 70 mm, or even between 10 mm and 40 mm, or even between 15 mm and 30 mm.

According to one embodiment, the LASER heating device 108 is configured to move the LASER beam at the decorative coating layer 13 at a speed, in the transverse direction, of between 0.2 meters per second (m/s) and 10 m/s. This speed range makes it possible to distribute the heat sufficiently homogeneously at the decorative coating layer 13. According to the embodiments, the speed range is between 1 m/s and 5 m/s, or even between 2 m/s and 3 m/s.

According to one embodiment, the LASER heating device 108 is configured to generate a number of passes of the LASER beam at each point of the decorative coating layer 13 between 1 and 200. This range of numbers of passes makes it possible to maintain the local temperature level above a threshold value for a time greater than a predetermined threshold duration. According to the embodiments, the number of passes is between 2 and 50, between 5 and 20, or even between 10 and 15.

According to yet another embodiment, the LASER heating device 108 comprises a plurality of LASER diodes, each LASER diode illuminating a respective portion of the glass panel. laminated coated 1 facing the LASER diode (each light beam being, where appropriate, guided by a respective optical fiber). The plurality of LASER diodes is arranged so as to generate as uniform an illumination as possible of the underlying plane in which the decorative coating layer 13 is arranged. For example, between 100 and 2000 LASER diodes are used. Following a series of tests, it is identified that the heating system 103 can be configured to generate, at the decorative coating layer 13, a surface energy of between 400 and 1500 kiloJoules per square meter (kJ/m ² ) of panel. This range makes it possible to exceed, at the decorative coating layer 13, an average temperature threshold allowing the crosslinking of the decorative coating layer 13, without any burning effect and without any undesirable effect on the underlying layer of polymer interlayer material. According to the embodiments, the heating system 103 is configured to generate, at the level of the decorative coating layer 13, a surface energy of between 450 and 850 kJ/m ² , between 500 and 800 kJ/m ² , between 550 and 750 kJ/m ² , or even between 600 and 700 kJ/m ² .

The parameterization of the LASER heating device may depend in particular on the characteristics of the decorative coating. For example, in the case where the decorative coating comprises a reflective layer, for example a silver layer, it may be necessary to provide a higher surface energy, for example between 850 and 1500 kJ/m ² , even if an opaque layer is arranged between this silver layer and the coating layer to be polymerized. Alternatively or in addition, if the decorative coating comprises several layers of a distinct nature, the thermal characteristics of the layers may differ, which may have an effect on the parameterization of the LASER heating device.

The parameters of the installation, in particular the linear speed of movement of the panel in the oven, the power of the heating devices 107, the average power of the transmitter 109, the interline spacing, the defocusing, the speed of movement of the LASER beam in the transverse direction, the number of passes, as presented above, can be adjusted, in the ranges presented above, to obtain this surface energy.

The location of interception of the LASER beam with the decorative coating layer 13 is for example offset from the inlet 105 by at least one tenth of the length of the oven, in particular by at least one fifth of the length of the oven. Thus, the oven is designed to have a first zone 110, close to the inlet 105, in which both convective heating and radiative heating are implemented to promote the evaporation of the solvents of the decorative coating layer 13, and a second zone 111, downstream, for drying the decorative coating layer 13. The location of interception of the LASER beam with the decorative coating layer 13 is located in the second zone 111, in particular in an upstream zone of this second zone 111. The emitter 109 is for example arranged vertically of this interception location, so as to minimize the optical path of the LASER beam. Alternatively, a second heating device 107 is not provided downstream of the LASER heating device 108.

In the case of a continuous furnace, the above-mentioned set temperature range is determined in a longitudinally central section of the furnace. Indeed, in a furnace inlet zone, if the laminated glass panels come from an exterior of the furnace at room temperature, the initial temperature of the polymer interlayer material can also be at room temperature.

In a particular embodiment, the ratio P_cata is chosen in the range [0.1% - 5%], more particularly in the range [0.5% - 2.5%] or more particularly [0.75% - 1.25%]. In a particular embodiment, the ratio P cata is equal to 1%. For each of the four options for choosing the proportion P cata above, the set temperature in the furnace enclosure T ext can be chosen:

- in the range [120°C; 140°C], the duration t_chauff then being less than or equal to 7.5 minutes and optionally greater than 3 minutes,

- in the range [100°C; 120°C], the duration t_chauff then being greater than or equal to 7.5 minutes; in particular if the upper glass sheet 1 la is made of clear glass and has a thickness of between 2 mm and 6 mm, and if the decorative coating layer has a thickness before drying of between 50 pm and 20 pm.

In a particular embodiment, the at least one decorative coating layer 13 consists of one or more layers of lacquer.

In another embodiment, the decorative coating comprises at least one layer of reflective material, so as to form a mirror.

The thickness of the layer of reflective material may be adapted to obtain a surface mass of silver greater than the standard of 700 mg/m ² . Since the reflective material is subject to oxidation and has little mechanical resistance, a layer of protective varnish may be applied to the layer of reflective material.

According to another embodiment, the heating system 103 does not comprise heating devices 107. In this case, the heating is carried out exclusively by the LASER heating device 108. The LASER heating device 108 can then comprise several emitters 109 arranged along the path of the laminated glass panel and generating distinct LASER beams intercepting the laminated glass panel along its path.

A laminated glass panel is thus obtained comprising at least two sheets of glass and in which at least two successive sheets of glass are assembled by means of a polymer interlayer material, the laminated glass panel having an upper face 1 lal and a lower face 1 Ibl, and the upper face of the laminated glass panel 1 lal is coated with at least one decorative coating layer 13 formed from a fluid decorative material and the polymer interlayer material of which does not have any bubbling defect observable to the naked eye. In one embodiment of the coated laminated glass panel, the interlayer polymer material is tinted. In the case where the laminated glass panel is coated with a reflective material so as to form a mirror, this arrangement makes it possible in particular to obtain a tinted mirror, for example bronze-colored, without having to resort to the usual processes for tinting mirrors, a process of heavy and costly implementation.

In one embodiment of the coated laminated glass panel, heating means are incorporated either in the polymer interlayer material or in at least one of the two glass sheets. For example, heating micro-fabrics may be incorporated in PVB, or one of the two glass sheets or the glass panel may be of the EGLAS® type from Saint Gobain(R). This arrangement makes it possible to obtain a heated coated glass panel, such as a heated mirror, whose mechanical strength is improved compared to the solutions of the prior art.

The invention finally relates to the use of a laminated glass panel:

- in the construction sector, in particular for the creation of decorative partitions or floors that meet the required safety standards,

- or in the field of furniture for the production of furniture comprising walls or decorative wall elements complying with the required safety standards, for example custom-made furniture.

Example 1:

An oven 101 as presented above, equipped with a conveying system at a longitudinal speed of 5 meters per minute (m/min) comprises a LASER heating device 108 emitting a LASER beam of wavelength 1070 nanometers (nm) as the only heating system. The LASER heating device is configured as follows: Power: 40 W,

Beam movement speed: 1.5 m/s,

Line spacing: 20pm,

Defocus: 5 mm,

Number of passages: 80.

A test of the resistance of the coating layer of the coated laminated glass panel is carried out following the heat treatment. The test consists of rubbing an optical paper soaked in acetone along a predetermined trajectory on the coating layer, and visually checking the presence of the coating layer on the optical paper at the end. For products manufactured according to the example above, the optical inspection does not reveal any presence of a coating layer on the optical paper, allowing it to be concluded that the coating layer is well maintained on its substrate.

Example 2: An oven 101 as presented above, provided with a conveying system at a longitudinal speed of 5 meters per minute (m/min) comprises a heating device 107 and a LASER heating device 108 comprising a network of 200 continuous LASER diodes of

100 W each, each emitting a LASER beam of wavelength 976 nanometers (nm), and arranged in a matrix, and a set of optical fibers respectively guiding the LASER beam to a respective location in the furnace. The diameter of the focal spot at the coating layer is 60 millimeters, obtained by divergence of the optical beam at the fiber output.

A test of the resistance of the coating layer of the coated laminated glass panel is carried out following the heat treatment. The test consists of rubbing an optical paper soaked in acetone along a predetermined trajectory on the coating layer, and visually checking the presence of the coating layer on the optical paper at the end. For products manufactured according to the example above, the optical inspection does not reveal any presence of a coating layer on the optical paper, allowing it to be concluded that the coating layer is well maintained on its substrate.

LIST OF REFERENCE SIGNS

1: coated laminated glass panel l ia: top glass sheet

1 lal: upper face of the laminated glass panel to be coated

11b: lower glass sheet

1 Ibl: lower face of the laminated glass panel to be coated

12: interlayer of polymer material

13: decorative coating layer

101: oven

102: enclosure

103: heating system

104: conveyor system

105: entrance

106: exit

107: heating device

108: LASER heating device

109: Transmitter

110: First zone

111: second zone

112: drying device

Claims

1. Method of manufacturing a coated laminated glass panel comprising: - a laminated glass panel to be coated is provided comprising at least two glass sheets (1 la, 11b) and in which at least two successive glass sheets are assembled by means of a polymer interlayer material forming after assembly an interlayer (12), the laminated glass panel to be coated having at least one upper face (1 lal) to be coated; - a flowing decorative material is provided; - at least one decorative coating layer (13) is formed by applying the decorative material in the fluid state to the upper face (1 lal) of the laminated glass panel to be coated; - the decorative coating layer is dried by heating the laminated glass panel thus covered using a drying device, Characterized in that the drying device has a set temperature at the polymer interlayer material (T_int) greater than or equal to 60°C and less than 100°C, and in that the drying device (112) comprises at least one LASER heating device (108) adapted to emit a beam in the direction of the decorative coating layer (13). 2. A method of manufacturing a coated laminated glass panel according to claim 1 in which the polymer interlayer material is selected from polyvinyl butyral, ethylene vinyl acetate, an ionoplast polymer, thermoplastic polyurethane and a casting resin. 3. A method of manufacturing a coated laminated glass panel according to claim 1 or 2, wherein the at least one decorative coating layer consists either of a layer of reflective material and one or more layers of protective varnish or of one or more layers of lacquer and optionally one or more layers of protective varnish. 4. A method of manufacturing a coated laminated glass panel according to one of claims 1 to 3, in which a chemical hardener or a crosslinking catalyst is incorporated into the fluid decorative material in a ratio P_cata between the mass of chemical hardener or crosslinking catalyst and the mass of decorative material in the determined fluid state, and in which the ratio P_cata of the mass of chemical hardener or crosslinking catalyst or crosslinking catalyst and the mass of decorative material in the fluid state is greater than 0.1%. 5. A method of manufacturing a coated laminated glass panel according to claim 4, in which the chemical hardener or the crosslinking catalyst is chosen from acid catalysts and optionally from hydrofluoric acid, phosphoric acid and paratoluenesulfonic acid. 6. A method of manufacturing a coated laminated glass panel according to one of claims 1 to 5, in which the drying device (112) further comprises at least one heating device (107) adapted to carry out convective and radiative heating. 7. A method of manufacturing a coated laminated glass panel according to one of claims 1 to 6, wherein a conveying system (104) moves the coated laminated glass panel (1) in the drying device (112) between an inlet (105) and an outlet (106) defining a length of the furnace, and wherein the LASER heating device (108) is adapted to emit the beam towards a beam interception location with the decorative coating layer (13) offset from the inlet (105) by at least one tenth, in particular at least one fifth, of the length of the furnace. 8. A method of manufacturing a coated laminated glass panel according to claims 6 and 7, wherein said heating device (107) adapted to carry out convective and radiative heating is arranged upstream of the LASER heating device (108). 9. A method of manufacturing a coated laminated glass panel according to one of claims 1 to 8, wherein said set temperature (T_int) is less than 80°C. 10. Method for manufacturing a coated laminated glass panel according to any one of claims 1 to 9, in which at least one of the following characteristics is further implemented: - the heating system (103) is configured to generate at the decorative coating layer (103) a surface energy of between 400 and 1500 kJ/m ² of panel, in particular between 450 and 850 kJ/m ² , 500 and 800 kJ/m ² , between 550 and 750 kJ/m ² , or even between 600 and 700 kJ/m ² ; - an emitter (109) of the LASER heating device emits a LASER beam at a power of less than 100 W, in particular less than 50 W, less than 40 W, less than 35 W, or even less than 30 W; - the LASER heating device (108) is configured to have an inter-line gap of between 10 microns and 100 microns, in particular between 25 and 85 microns, or even between 35 and 75 microns; - the LASER heating device (108) is configured to have a defocusing at the decorative coating layer (13) of between 5 mm and 50 mm, in particular between 10 mm and 40 mm, or even between 15 mm and 30 mm; - the LASER heating device (108) is configured to move the LASER beam at the decorative coating layer (13) at a speed of between 0.2 m/s and 10 m/s, in particular between 1 m/s and 5 m/s, or even between 2 m/s and 3 m/s; - the LASER heating device (108) is configured to generate a number of passages of the LASER beam at each point of the decorative coating layer (13) between 1 and 200, in particular between 2 and 50, between 5 and 20, or even between 10 and 15; - the LASER heating device (108) comprises a plurality of LASER diodes, in particular between 100 and 2000 LASER diodes. 11. Manufacturing method according to any one of claims 1 to 10, in which a laminated glass panel to be coated is provided comprising at least one layer of silver having said upper face (1 lal) to be coated. 12. Manufacturing method according to any one of claims 1 to 11, in which said LASER heating device (108) is adapted to emit said beam in the near infrared towards the decorative coating layer (13). 13. System for manufacturing a coated laminated glass panel comprising: - a laminated glass panel to be coated comprising at least two glass sheets (1 la, 11b) and in which at least two successive glass sheets are assembled by means of a polymer interlayer material forming after assembly an interlayer layer (12), the laminated glass panel to be coated having at least one upper face (1 lal) to be coated; - a fluid decorative material; - an application device adapted to apply decorative material in the fluid state on the upper face (1 lal) of the laminated glass panel to be coated to form at least one decorative coating layer (13); - a drying device (112) adapted to dry the decorative coating layer by heating the laminated glass panel thus covered with a set temperature at the polymer interlayer material (T_int) greater than or equal to 60°C and less than 100°C, the drying device (112) comprising at least one LASER heating device (108) adapted to emit a beam towards the decorative coating layer (13). 14. A system for manufacturing a coated laminated glass panel according to claim 13, further comprising at least one of the following features: - the heating system (103) is configured to generate at the decorative coating layer (103) a surface energy of between 400 and 1500 kJ/m ² of panel, in particular between 450 and 850 kJ/m ² , in particular between 500 and 800 kJ/m ² , between 550 and 750 kJ/m ² , or even between 600 and 700 kJ/m ² ; - an emitter (109) of the LASER heating device is adapted to emit a LASER beam at a power of less than 100 W, in particular less than 50 W, less than 40 W, less than 35 W, or even less than 30 W; - the LASER heating device (108) is configured to have an inter-line gap of between 10 microns and 100 microns, in particular between 25 and 85 microns, or even between 35 and 75 microns; - the LASER heating device (108) is configured to have a defocusing at the decorative coating layer (13) of between 5 mm and 50 mm, in particular between 10 mm and 40 mm, or even between 15 mm and 30 mm; - the LASER heating device (108) is configured to move the LASER beam at the decorative coating layer (13) at a speed of between 0.2 m/s and 10 m/s, in particular between 1 m/s and 5 m/s, or even between 2 m/s and 3 m/s; - the LASER heating device (108) is configured to generate a number of passages of the LASER beam at each point of the decorative coating layer (13) of between 1 and 200, in particular between 2 and 50, between 5 and 20, or even between 10 and 15; - the LASER heating device (108) comprises a plurality of LASER diodes, in particular between 100 and 2000 LASER diodes. 15. System for manufacturing a coated laminated glass panel according to claim 13 or 14, wherein said LASER heating device (108) is adapted to emit said beam in the near infrared towards the decorative coating layer (13).