FR3124761A1 - method for assembling laminated glazing and calender for implementing the method - Google Patents

Abstract

The device (7) comprises one or more radiation sources (UV1; UV2) to heat a thermoplastic sheet (T) and make it adhesive within a stack (E) in which it is arranged between two glass sheets (V1 , V2). These radiation sources are arranged in one and/or the other of two rollers (R1, R2) which press between them the stack (E) which passes between them to cause the thermoplastic sheet (T) to adhere to the one and/or the other sheet of glass (V1, V2). The circumferential wall of the rollers (R1, R2) allows the radiation from the corresponding radiation sources (UV1, UV2) to pass at least partially so as to reach the stack (E) which passes between them. It is thus possible to take full advantage of a skin effect of the heating of the thermoplastic sheet (T) by choosing an appropriate radiation which is little absorbed by the glass sheet(s) (V1, V2). Figure for abstract: Fig. 13

Description

method for assembling laminated glazing and calender for implementing the method

The present invention relates to the field of the manufacture of laminated glazing comprising two sheets of glass and an interlayer thermoplastic sheet. More particularly, it relates to the deaeration step implemented after stacking the two sheets of glass and the interlayer thermoplastic sheet and before its treatment in an autoclave.

Laminated glazing is commonly used in the automotive, aeronautical and building sectors. They generally consist of two sheets of glass between which is placed a thermoplastic sheet – typically polyvinyl butyral (PVB) – which ensures their adhesion between them. Good quality laminated glazing should be transparent and free of bubbles.

Traditionally, the manufacture of such laminated glazing mainly comprises three successive steps, namely the stacking of the two sheets of glass with the interposition of the thermoplastic sheet, deaeration and treatment in an autoclave.

The purpose of the deaeration step is to cause the two glass sheets to adhere to the thermoplastic sheet after heating, while eliminating most of the air present between the thermoplastic sheet and each of the glass sheets. It consists of continuously scrolling the stack through a radiant oven to heat it, then between the pressing rollers of a calender arranged at the exit of the oven where the thermoplastic sheet is still at a sufficient temperature to make it adhere. with sheets of glass. At the end of this step, the adhesion between the thermoplastic sheet and the glass sheets is sufficient to preserve their assembly during subsequent handling while waiting for its treatment in the autoclave which will give it final adhesion.

More specifically, after the de-aeration step, the laminated glazing units are raised and placed offline in an inclined position close to the vertical on trestles in the form of a batch of several laminated glazing units. The trestles loaded with their laminated glazing are brought into an autoclave in which, when it is filled, the laminated glazing is subjected to a cycle of pressure (of the order of 10 bars) and temperature (of the order of 140° C) which lasts several hours. The treatment in the autoclave ensures the definitive adhesion between the thermoplastic sheet and the glass sheets and serves to confer the desired transparency to the glass sheets, as well as to dissolve in the thermoplastic sheet the air which remained between the sheets of glass and the thermoplastic sheet after the deaeration step.

The radiative furnace technology usually used during the deaeration step is based on infrared lamps whose blackbody spectrum corresponds to filament temperatures between 900 and 1200°C. Such an oven has the disadvantage of requiring a lot of energy and typically uses heating by infrared lamps over a distance of 4 to 10 m. This is explained by the fact that, on the one hand, the glass sheet first absorbs a large part of the incident flux, typically 50% to 80% for filament temperatures of infrared lamps between 500°C and 1000° C and for a glass thickness of 2mm. Thus, the first sheet of glass encountered by the incident infrared radiation prevents the interlayer thermoplastic sheet of the laminated glazing - in particular the PVB - from directly absorbing a major part of the incident flux. On the other hand, at a given wavelength, the proportion of energy of the incident infrared radiation absorbed by the glass increases exponentially with its thickness which can exceed 10 mm, which further limits the proportion of the energy of the infrared radiation which reaches the interlayer thermoplastic sheet directly. As a result, the stack is heated throughout its thickness with a significant contribution of heat conduction from the glass to the thermoplastic sheet to heat the latter. And the more the laminated glazing comprises thick sheets of glass, the longer and/or more powerful the heating must be. In addition, there is a risk of adhesive bonding between the thermoplastic sheet and the glass sheets at the rear of the stack relative to the direction in which it travels under the combined effect of heating at the rear and pressing by grille in a more forward region, which may prevent adequate ventilation from being achieved.

Finally, in the case of glass sheets coated with a thin layer of solar control or low-emissivity type, the majority of infrared radiation is reflected and the heating process becomes highly inefficient.

Another approach has been proposed in WO 2007/081541 for assembling laminated glazing without resorting to autoclave treatment. To this end, this document teaches to place the stack consisting of the two sheets of glass and the interlayer thermoplastic sheet, preferably PVB, in a sealed chamber placed under vacuum between 1kPa and 20kPa or approximately 30kPa and to carry out a heating the thermoplastic sheet and pressing to adhesively bond the glass sheets to the thermoplastic sheet. The pressing can be carried out by means of successive rolls and the heating is done by radiation sources arranged between the successive rolls, the stack of the glass sheets and the thermoplastic sheet being moved in an oscillating manner under the successive rolls. The radiation source is chosen in the microwave or infrared range with a frequency selected so as to favor the heating of the thermoplastic sheet. The energy density of the radiation is chosen so as to obtain a heating rate between approximately 0.5°C/s and 5°C/s, it being specified that faster heating would have the disadvantage of having to resort to autoclave treatment. .

This approach nevertheless has the disadvantage of having to resort to a vacuum chamber, which is not very suitable in the case of large-sized glazing that may have several square meters. Furthermore, the heating process remains relatively slow, which limits production yield.

According to another approach aimed at improving the heating technology used during the deaeration step while continuing to use a subsequent treatment in an autoclave, the applicant proposed in WO 2020/099800 to expose upstream of the pressing calender to the at least one side, preferably both sides, of the stack formed by the glass sheets and the intermediate thermoplastic sheet to radiation at wavelengths between 340 and 400 nm, and/or between 1.6 and 2.9 μm, having a spectral width of at most 100 nm, so as to heat the interlayer thermoplastic sheet through the glass sheets, to a temperature sufficient to adhere to the glass sheets during its subsequent passage through the pressing calender.

This document explains that the interlayer thermoplastic sheet such as PVB absorbs much more radiation at these wavelengths than glass. He specifies that a major interest thus lies in the efficiency of the heating by radiation in these particular wavelengths of a thin thickness of the interlayer thermoplastic sheet at its interface with the glass sheet, independently of the glass thickness. of the latter to pass through, and that this efficiency remains for significant thicknesses of the glass sheets, unlike heating with the infrared lamps of the prior art.

It teaches in particular that a UV source positioned before the calender makes it possible to quickly increase the temperature of the interface between the PVB and the glass and that it is possible, with the pressure applied by the calender, to deaerate immediately. the sample, it being specified that the UV energy is above all absorbed by the PVB. This method thus offers a gain in energy and makes it possible to overcome the typical inertia of infrared ovens.

As an example of implementation, this document mentions a 2 mm Planiclear® glass (SG Glass) - PVB Saflex® RB41 0.76 mm (Eastman Chemical Company) - 2 mm Planiclear® glass which is insulated with a single side with a UV LED lamp emitting a maximum power flux-density of 9 W/ ^cm2 at a wavelength of 365 nm (at least 90% of the total light energy is emitted in the spectral band 345-385 nm) . The sample moved at 0.4 m/min under the lamp and in a calender. The lamp was 5 cm before the calender at a distance of 3 mm from the sample, which was irradiated over its entire width, and over the length of the irradiation zone, which was 20 mm. After deaeration, the sample showed a level of haze and a level of clarity comparable to those obtained by the usual deaeration processes and after the autoclave, the sample being perfectly transparent and without bubbles.

The object of the present invention is to further improve the prior art. In particular, one objective is to further improve the energy performance and/or the production rate during the deaeration step or more generally during an assembly step of laminated glazing during which sheets of glass and an interlayer thermoplastic sheet made adhesive by heating are pressed together by calendering to adhesively bond the glass sheets to the thermoplastic sheet.

To this end, the invention proposes, according to a first aspect, a device for adhesively bonding two sheets of glass to a thermoplastic sheet which becomes adhesive by heating, which sheets are arranged beforehand in the form of a stack in which the thermoplastic sheet is interposed. between the two sheets of glass in direct contact with them. The device comprises at least a first radiation source for heating the thermoplastic sheet within the stack so as to make it adhesive, and a first roller and a second roller which are rotatably mounted to press the stack together as and as it passes between them so as to cause the thermoplastic sheet rendered adhesive by the first radiation source to adhere to at least one of the glass sheets. The first radiation source is arranged inside the first roller, and the circumferential wall of the first roller is adapted to allow the radiation from the first radiation source to pass at least partially so as to reach the stack during its passage between both rolls.

The fact that at least one source of radiation - preferably UV, but others are possible - is placed in the first roll and preferably also in the second roll which together form a pressing calender advantageously makes it possible to heat the thermoplastic sheet in the pressing area itself or in the immediate vicinity of it. This makes it possible to take full advantage of the skin effect of the heating of the thermoplastic sheet by UV or other radiation when the latter is little absorbed by the sheet of glass through which the radiation passes.

Indeed, the inventors have discovered that the solution of WO 2020/099800 A1 consisting in placing the source of radiation used to heat the thermoplastic sheet before the calender does not in reality make it possible to take full advantage of the heating skin effect, c that is to say the fact that a thin thickness of the interlayer thermoplastic sheet at its interface with the glass sheet can be heated quickly. This is due to the fact that the calendering does not intervene immediately as soon as a thin thickness of the thermoplastic sheet reaches a sufficient temperature to make it adhesive. Indeed, the stack formed by the glass sheets and the interlayer thermoplastic sheet must cover the distance separating the source of radiation from the pressing zone of the calender. Although this distance is quite low, the time required to cover it nevertheless allows a significant cooling of the thin thickness of thermoplastic sheet at its interface with the glass sheet by the effect of the conduction-diffusion of heat in the rest of the thermoplastic sheet and in the glass sheet. In the example given in this document where the radiation source was located 5 cm before the calender, it took 7.5 seconds for the stack to reach the center of the pressing zone of the calender, having regard to the speed of scrolling of 0.4 m/min. Consequently, the radiation source must provide a quantity of heat to the thermoplastic sheet much greater than that which is sufficient to make adhesive a thin surface thickness of material of the thermoplastic sheet, this in order to ensure that the surface temperature of the sheet thermoplastic is still sufficient to be adhesive on the surface when the stack is pressed by the calender. In addition, this example corresponds to experimental test conditions that are very different from an industrial implementation. Indeed, the 5 cm proximity of the lamp to the grille was only possible due to a very small diameter of the pressing rollers of the grille, namely a diameter of about 3 cm, which were additionally devoid of soft coating. This unusually small diameter does not correspond to the industrial reality where the diameter of the pressing rolls is generally more than 10 times larger, or even much more, and is covered with a soft coating for a soft contact in a pressing zone having a length of a few centimeters in the direction of travel of the stacks, for example of the order of 5 cm. As a result, even a space-saving LED-based UV radiation source cannot actually be placed so close to the pressing area of the stack, let alone the centerline of the pressing area. . In other words, the actual industrial situation is even more unfavorable than that of these experimental tests.

On the contrary, in the invention, the fact of placing the source of radiation in a calender roll allowing the radiation to pass at least partially makes it possible to locally bring the surface temperature of the thermoplastic sheet to the level required to make it adhesive on the surface at a when this part of the thermoplastic sheet is in the pressing zone of the rollers of the calender or at least at a very short distance from the latter. In this way, the cooling effect of the surface layer of material of the thermoplastic sheet by heat conduction in the rest of the thermoplastic sheet and in the adjacent glass sheet essentially occurs after pressing. Therefore, it is possible to take maximum advantage of the heating skin effect of the thermoplastic sheet, which avoids the need to supply excess heating energy.

In addition, it is possible to very quickly reach the desired surface temperature to make the thermoplastic sheet adhesive at the interface with the glass sheet. In fact, flash heating can be applied to it, making it possible to reach the desired temperature by resorting to a high heating radiation intensity. The surface temperature to be reached is generally between 50°C and 80°C depending on the material of the thermoplastic sheet, in particular in the case of PVB. As we will see later, it can be reached in much less than a second. In practice, it can be reached easily in less than 0.5 seconds, or even in less than 0.2 seconds. It suffices for this to resort to a high radiation intensity since a major part of the radiation passes through the glass sheet and reaches the thermoplastic sheet. A UV source in particular in the form of one or more LED strips is quite suitable for this purpose in the case of conventional glass sheets which are particularly transparent to UV. Today, they can easily provide an intensity greater than 10 W/cm ² , or even more than 50 W/cm ² . It is thus possible to resort to travel speeds of the stacks through the pressing calender which can be clearly greater than 1 m/min: it can thus be greater than 5 m/min, or even greater than 9 m/min. Other types of radiation sources can of course be envisaged for the same purposes depending on the transmission characteristics of the glass sheets concerned. In particular, use may be made of the range between 1.6 and 2.9 μm as taught by WO 2020/099800 A1.

According to preferred embodiments, the device of the invention comprises one or more of the following characteristics:

• the device comprises at least one second radiation source for heating the thermoplastic sheet within the stack so as to make it adhesive, in which the second radiation source is arranged inside the second roller, and the peripheral wall of the second roller is adapted to allow the radiation from the second radiation source to pass at least partially so as to reach the stack as it passes between the two rollers;
• at least a part of the circumferential wall of the first and/or of the second roller has a transparency allowing the radiation from the corresponding radiation source to pass at least partially through the roller in question, said part preferably extending continuously over the entire circumference of the roller considered;
• the rate of transmission of said circumferential wall part is at least 50% and more preferably at least 70% for a given wavelength or a given range of wavelengths included in the radiation from the source of corresponding radiation;
• the peripheral wall of the first and/or of the second roller has openings distributed circumferentially to let the radiation from the corresponding radiation source pass, the peripheral wall being preferentially opaque to the radiation from the corresponding radiation source outside the openings;
• reflecting surfaces are arranged on the circumferential wall of the inner side of the roller between successive openings in the circumferential direction to reflect the radiation from the corresponding radiation source towards an adjacent opening;
• at least a part of the openings is made in the form of slots;
• the openings of the circumferential wall pass through so that the radiation from the corresponding radiation source can follow a path free of material as far as the stack, it being specified that free of material means the absence of solid material passed through by radiation, and not the absence of air or, where appropriate, of another surrounding gaseous material;
• the circumferential wall comprises a first thickness of material that is opaque to the radiation from the corresponding radiation source, and a second thickness of material having a transparency allowing the radiation from the corresponding radiation source to pass at least partially, the openings passing through only the first thickness of material and are covered by the second thickness of material;
• the device comprises a circuit for controlling the first and/or the second radiation source to activate it when an opening of the circumferential wall of the corresponding roller is located in the radiation path of the radiation source and to deactivate it when an opaque portion of the circumferential wall of the corresponding roller is located in the radiation path of the radiation source;
• the first and/or the second radiation source is arranged inside the corresponding roller independently of the rotation of the roller, the first and/or the second radiation source preferably being of directional radiation and arranged inside the corresponding roller so that, in use, the radiation from the radiation source reaches the stack in a fixed direction as it passes between the first and second rollers;
• with reference to the direction in which the stack passes between the first roller and the second roller, the zone of impact of the radiation from the first and/or the second radiation source on the stack during its passage between the first and second rollers is at least partially included in the zone of contact of the corresponding roller with the stack and, more preferentially, at least 10%, more preferentially still at least 20% of the radiation impact zone of the first and/or or of the second source of radiation on the stack is included in the contact zone of the corresponding roller with reference to the direction in which the stack passes between the rollers;
• with reference to the direction of passage of the stack between the first roller and the second roller, the fictitious plane defined by the axes of rotation of the first and second rollers intersects the zone of impact of the radiation of the first and/or the second source of radiation on the stack as it passes between the first and second rollers, the fictitious plane preferentially intersecting the impact zone in its middle;
• the first and/or the second radiation source is a UV source with wavelengths between 340 and 450 nm, and more preferably between 340 and 400 nm, or else an infrared radiation source with wavelengths between 1 6 and 2.9 μm, more preferably between 2.2 and 2.7 μm, and with a spectral width of at most 500 nm, more preferably of at most 250 nm, and even more preferably of at most 100 nm;
• the device is provided to exert a level of pressure on the stack as it passes between them which is high enough to eliminate a major part of the air present between the thermoplastic sheet and the glass sheets;
• the device is provided that the first roller and the second roller apply to the stack a pressure of between 0.1 and 1 MPa, limits included;

According to another aspect, the invention proposes a process for manufacturing laminated glazing from two sheets of glass and a thermoplastic sheet which becomes adhesive by heating, comprising the steps consisting in:

• providing the two sheets of glass and the thermoplastic sheet in the form of a stack in which the thermoplastic sheet is interposed between the two sheets of glass in direct contact with them, and
• scroll the stack between the first roll and the second roll of a device according to the first aspect of the invention which has just been described, to press the stack between them as it passes between them,

in which :

• the first and/or the second radiation source of the device are activated at least during the passage of the stack between the first and second rollers to heat the thermoplastic sheet within the stack so as to make it adhesive, and
• the first roller and the second roller of the device press together the stack as it passes between them to cause the thermoplastic sheet rendered adhesive by the first and/or second radiation source to adhere to one and/or the other sheets of glass.

According to preferred embodiments, the method of the invention comprises one or more of the following characteristics:

• the first and/or the second radiation source are selected so that: the glass sheet arranged on the side of the first roller, respectively on the side of the second roller, has a transmission rate of at least 50%, more preferably of at least 75%, and even more preferably at least 85% with respect to the part of the radiation from the radiation source considered which reaches the stack, and the thermoplastic sheet has an absorption rate of at least 50%, more preferably at least 75%, and even more preferably at least 85% with respect to the part of the radiation from the radiation source under consideration which reaches the thermoplastic sheet after passing through the sheet of glass on the side of the first roll, respectively on the side of the second roll;
• the first roller and the second roller exert a level of pressure on the stack as it passes between them which is high enough to eliminate a major part of the air present between the thermoplastic sheet and the glass sheets;
• the pressure applied by the first roller and the second roller on the stack is between 0.1 and 1 MPa, limits included;
• the running speed of the stack between the first and second rollers is selected so that the stack is locally subjected to radiation from the first and/or from the second radiation source for an exposure time of less than 2 seconds, preferably less than 1 second, more preferably less than 0.5 second and even more preferably less than 0.25 second, or even less than 0.2 second, the intensity of the radiation from the first and/or the second radiation source being chosen to locally heat the thermoplastic sheet at its interface with the glass sheet located on the side corresponding to the radiation source considered during the exposure time to the point of making the thermoplastic sheet adhesive locally at this interface and allowing the pressing of the stacking by the rollers to locally adhere the thermoplastic sheet to this sheet of glass;
• the method further comprises a step of treating the stack in an autoclave after passing the stack between the first and the second roll.

Other aspects, characteristics and advantages of the invention will appear on reading the following description of a preferred embodiment of the invention, given by way of example and with reference to the appended drawing.

represents graphs giving the rate of transmission and the rate of absorption of the radiation by, respectively, a sheet of glass 2 mm thick and a sheet of PVB according to the wavelength.

represents the same graphs as the , but in the case of a 4 mm thick glass sheet, the PVB sheet being the same.

represents the same graphs as the for the same sheet of glass and the same sheet of PVB, but over a larger wavelength range.

represents graphs giving one the rate of transmission of the radiation according to the wavelength for a so-called "low emissivity" layer with which is provided a 4 mm glass sheet identical to that of the , the other graph providing the radiation absorption rate as a function of the wavelength by the same sheet of PVB after transmission by the “low emissivity” layer and this sheet of glass.

represents the temperature curve through a stack formed of two sheets of glass and an interposed PVB sheet when the stack is heated by UV radiation.

represents for the same stack as the temperature curves relating to the PVB sheet as a function of time during heating by UV radiation.

represents the same curve for the same stack as for the , but in the case where the stack is subjected to heating by IR.

represents the same curves for the same stack as for the , but in the case where the stack is subjected to heating by IR.

represents the temperature curve through a stack formed of two sheets of glass and an interposed PVB sheet when the stack is heated by UV radiation, the glass sheets being thicker than in the case of the stack of figures 5 to 8.

represents for the same stack as the temperature curves relating to the PVB sheet as a function of time during heating by UV radiation.

represents the same curve for the same stack as for the , but in the case where the stack is subjected to heating by IR.

represents the same curves for the same stack as for the , but in the case where the stack is subjected to heating by IR.

schematically represents a deaeration station according to a preferred embodiment of the invention.

schematically represents a local enlargement of the contact zone of a pressing roller on the glass sheet of a stack passing between the rollers of the calender of the deaeration station of the .

schematically represents a variant of the deaeration station of the .

schematically shows a top view of a calender roll of the deaeration station of the .

Figures 1 to 4 show the advantage of using a source of UV radiation to heat the thermoplastic sheet in order to make it adhesive and therefore be able to bond it to the adjacent glass sheets by pressing. They represent the transmission spectra of a glass sheet, with and without functional layer, and the absorption spectra of a PVB sheet.

On the graphs of four figures, the abscissa represents the wavelength in microns and the ordinate represents the fraction of light transmitted or absorbed as the case may be.

On the , the dashed-dot line (a) represents the absorption rate of a 0.76 mm thick PVB sheet, marketed by Eastman Chemical Company under the registered trademark Saflex® RB41, and the solid line (b) the rate of transmission of a sheet of glass 2 mm thick sold by Saint-Gobain Glass under the Planiclear® brand. On the , the dashed-dot line (a) represents the absorption rate of the same PVB sheet as on the , but the continuous line (b) this time represents the transmission of a sheet of glass 4 mm thick marketed by Saint-Gobain Glass under the Planiclear® brand.

For UV radiation between 340 and 450 nm, the glass is transparent and the PVB very absorbent, as shown by the two figures 1 and 2. This spectral window is therefore ideal for directly heating the PVB without the radiation being absorbed by the glass. Selective heating makes it possible to reduce the absorption of radiation in areas other than the PVB at the glass-PVB interface and therefore to reduce the energy used, thus making it possible to reduce the costs of the process.

There provides the same curves as the for the same glass sheet and the same thermoplastic sheet, but this time for a wider wavelength interval. It shows that there is a similar interest for the spectral window between 1.6 and 2.9 μm, and more particularly between 2.2 and 2.7 μm.

On the , the dotted line (d) represents the transmission of a so-called “low-e” / “low emissivity” thin layer marketed by Saint-Gobain Glass under the Planitherm® ONE brand, on a 4 mm glass sheet thick. The dashed-dot line (e) represents the part of radiation which is absorbed by the PVB after transmission through the thin film and the glass.

For assemblies of this type comprising thin layers reflecting infrared radiation, the transmission window of the glass is preserved and the efficiency of the process is only slightly affected by the addition of the thin layer on the glass in the field of wavelengths between 340 and 450 nm, but not between 1.6 and 2.9 µm. In this case, the thin layer hardly transmits the wavelengths between 1.6 and 2.9 µm, of which it reflects a large part, whereas radiation with wavelengths between 340 and 450 nm remains very widely transmitted. through this thin layer.

The graphs of Figures 5 to 12 provide the results of a comparative study illustrating the advantage of using a source of UV radiation compared to infrared to heat the interlayer thermoplastic sheet of the stack in order to make it adhesive and to be able to thereby binding it to the adjoining glass sheets by pressing.

The incident intensity is chosen identical for each type of radiation in order to show the intrinsic interest of using UV radiation compared to an IR incandescent lamp. In practice, it will be noticed that UV LEDs are generally more intense, potentially by a rate of 2 to 10.

In this case, the incident intensity of the radiation sources is 60W/cm ² uniformly over a zone 2 cm wide, it being specified that the direction of the width of this zone corresponds in practice to the direction of travel stacking through the grille. In addition, it covers the entire width of the stack formed by the two sheets of glass and the interlayer thermoplastic sheet, it being specified that the width of the stack corresponds in practice to the horizontal direction perpendicular to the running direction of the stacking through the grille.

Radiant heating is performed from one side of the stack only to show the skin effect of UV heating in the thermoplastic sheet. In other words, the radiation source is placed on the side of one of the two main faces of the stack. In practice, radiation heating is preferably applied from both sides of the stack. In this case, the UV source radiates at a wavelength of 365 nm while the IR lamp has a black body spectrum at a temperature of 1200°C.

It was assumed that a satisfactory adhesive bond and good air release are obtained if calender pressing occurs when the glass-PVB interface on the radiation source side reaches a temperature of 80°C. In other words, the radiation from the source is stopped as soon as the temperature of 80° C. is reached by the PVB at this interface. In practice, the adequate temperature level is actually lower, namely between 40°C and 60°C inclusive.

Figures 5 to 8 provide the results for the case of laminated glazing made up of two sheets of glass 2 mm thick each and a PVB interlayer sheet 0.76 mm thick.

More particularly, FIGS. 5 and 6 relate to the case where use is made of the UV radiation source. There shows on the ordinate the temperature level inside the stack as a function of the distance, indicated on the abscissa, which is measured from the outer surface of the glass sheet located on the side of the radiation source.

There shows the temperature level in the thermoplastic sheet as a function of the time, indicated on the abscissa, during which the UV radiation is applied to the stack. More particularly, the continuous curve (A) is the temperature of the PVB sheet at the interface with the glass sheet located on the side of the UV radiation source, the dashed curve (B) is the maximum temperature reached in the PVB sheet and the dashed-dot curve (C) is the temperature of the PVB sheet at the interface with the glass sheet located on the side away from the UV radiation source.

Figures 7 and 8 are the same graphs as for Figures 5 and 6, but for the case where use is made of the IR radiation source.

Figures 9 to 12 provide the same result graphs as Figures 5 to 8, but for the case of laminated glazing made up of two sheets of glass 10 mm thick each and an interlayer PVB of 0 .76mm thick.

Several lessons emerge from the graphs in Figures 4 to 11.

As regards laminated glazing comprising glass sheets 2 mm thick, the temperature of 80°C is reached at the PVB sheet - glass sheet interface located on the side of the radiation source in 0.135 seconds, this which corresponds in practice to a running speed of the stacks through the pressing calender of 8.9 m/min. On the contrary, it takes 0.88 seconds for this purpose in the case of the IR lamp, which corresponds in practice to a running speed of the stacks through the press calender of 1.4 m/min.

The UV source therefore allows six times faster heating than the IR source at equivalent radiation intensity.

With regard to the laminated glazing comprising the 10 mm thick glass sheets, the temperature of 80°C is reached at the interface PVB sheet - glass sheet located on the side of the radiation source in 0.17 seconds. in the case of the UV source, which corresponds in practice to a running speed of the stacks through the pressing calender of 7 m/min. The de-aeration operation is therefore only 20% slower compared to the case of laminated glazing comprising 2 mm thick glass sheets. On the other hand, it takes 6 seconds to reach this temperature in the case of the IR source, which would correspond to a running speed of the stacks through the pressing calender of only 0.2 m/min. In addition, the IR source leads in this case to extreme temperatures in the glass sheet, namely up to 500°C, which is potentially detrimental for it. In practice, it would be advisable to use a lower intensity of IR radiation, and therefore even slower heating, so as to homogenize the temperature through the glass by thermal conduction as it is heated and thereby avoid reaching damaging high local temperatures.

With regard to the case of the UV source, the graphs in Figures 6 and 10 also show that the temperature at the PVB sheet - glass sheet interface located on the side of the UV source decreases very rapidly after the UV source has been extinguished. Indeed, it goes from 80°C to 40°C in less than 0.9 seconds in both cases. This shows the advantage of involving the pressing of the stack as soon as the temperature at the interface PVB sheet - glass sheet has reached a sufficient level to make the PVB sheet adhesive on the surface or at least very quickly so that the PVB sheet is still adhesive on the surface when the pressing takes place. This is what makes it possible to place the radiation source inside the calender roll, unlike the case where it is placed outside the calender roll as in WO 2020/099800 A1.

A high radiation intensity can therefore be used to quickly reach the desired temperature at the glass sheet – thermoplastic sheet interface in order to be able to increase the speed of travel of the stacks through the pressing calender. However, it is best to keep the radiation intensity reaching the thermoplastic sheet within certain limits because, as shown in Figures 6 and 10, the maximum temperature reached inside the PVB sheet – namely around 110°C in this case - is clearly greater than that reached at the interface with the glass sheet and the latter is all the more important as the intensity of radiation reaching the thermoplastic sheet is high for a fixed heating time. Otherwise, there is the risk of locally damaging the material of the thermoplastic sheet if the temperature becomes locally excessive therein. From this point of view, it is preferable that the maximum temperature reached inside a PVB sheet be less than or equal to 140°C in the case of a PVB sheet.

An example of a laminated glazing assembly line according to the invention is as follows.

In a manner known per se, the assembly line begins with the supply of stacks E each formed by two sheets of glass V1, V2 and an adhesive thermoplastic sheet T interposed so as to be in direct contact with the two sheets of glass V1 , V2. As illustrated by the , the stacks E are transported by a conveyor 2 which brings them successively to a deaeration station 1 according to the invention, preferably in continuous scrolling at constant speed.

It is at the deaeration station 1 that the thermoplastic sheet T is heated by UV or other radiation through the circumferential wall of the rollers R1, R2 of a calender to make it adhesive while the stack E is pressed by these same rollers to bind the glass sheets V1, V2 to the thermoplastic sheet T. The level of pressing is chosen sufficient to deaerate the stack E, in other words to eliminate most of the air present between the thermoplastic sheet T and each of the sheets of glass V. The pressure applied by the rollers R1, R2 of the calender on the stack E is preferably between 0.1 and 1 MPa, limits included.

After leaving the deaeration station 1, the stacks E each forming a laminated glazing can be conventionally subjected to an autoclave treatment. In this case, it suffices that at the end of the deaeration step in station 1, the adhesion between the thermoplastic sheet T and the glass sheets V is sufficient to preserve their assembly during subsequent handling while waiting for the treatment of laminated glazing in the autoclave. The level of adhesion reached at the end of the deaeration stage may therefore be lower, or even much lower, than the final level of adhesion reached after treatment in the autoclave. The autoclave treatment can also serve conventionally to impart the desired transparency to the glass sheets V1, V2 and to dissolve in the thermoplastic sheet T the air which remained between the glass sheets V1, V2 and the thermoplastic sheet T at the from the deaeration stage in station 1.

It will be understood that alternatively, the deaeration technology disclosed can be used without resorting to an autoclave treatment, for example in the case where the deaeration step is designed to obtain the desired final level of adhesion.

As can be seen on the , the deaeration station 1 comprises a calender comprising two opposite pressing rollers R1 and R2 serving to press between them each stack E as it passes between the rollers R1 and R2. The roller conveyor 2 brings the stacks E between the rollers R1 and R2 preferably continuously at constant speed. The rollers R1 and R2 are driven in rotation in a counter-rotating manner at an identical circumferential speed which is preferably equal to the running speed of the roller conveyor 2. Thus, the rollers R1 and R2 in turn drive the stacks E which, after the rollers R1 and R2, arrive again on the roller conveyor 2 or directly on an unloading station. The axes of the rollers R1, R2 are conventionally oriented perpendicular to the direction of travel X of the stacks E on the roller conveyor 2. Preferably, the stacks E scroll conventionally horizontally on the roller conveyor 2 and are placed horizontally on this one.

A radiation source UV1, respectively UV2, is arranged inside the roller R1, respectively R2. This does not pose a problem because the external diameter of the rollers R1 and R2 is generally sufficient, all the more so since LED-based UV sources are not bulky. Thus, the sources of UV radiation can be arranged in rolls R1 and/or R2 of very different dimensions, for example having an outside diameter of between 200 mm and 3000 mm, more preferably between 350 mm and 2000 mm. They are preferably installed in a fixed position inside the corresponding roller R1, R2. In other words, sources UV1 and UV2 do not rotate with rollers R1 and R2. Sources UV1 and UV2 preferably have directional radiation, that is to say that their radiation is not omnidirectional when looking in the direction of the axis of rotation of the roller, but on the contrary it is generally directed in a same direction.

They are arranged so as to radiate towards the pressing zone of the stacks E between the two rollers R1, R2. Thus, the source UV1 serves to make the thermoplastic sheet T adhesive at the interface with the glass sheet V1 of a stack E located on the side of the roller R1 while the source UV2 serves to make the thermoplastic sheet T adhesive at the interface with the glass sheet V2 of a stack E located on the side of the roller R2.

Each of the sources UV1, UV2 is preferably a strip of UV LEDs. This extends parallel to the axis of the corresponding roller R1, R2. It preferably has a sufficient length to be able to radiate over the entire width of the stacks E which corresponds to the direction perpendicular to the running direction X. Alternatively, several strips of UV LEDs arranged parallel side by side can be provided to provide greater radiation width in the X scroll direction.

The circumferential wall of the rollers R1, R2 has a certain transparency to allow the radiation from the corresponding sources UV1, UV2 to pass at least partially.

To this end, their circumferential wall can be made of glass or a suitable plastic material with an adequate wall thickness to provide the appropriate mechanical resistance. The fact that the material constituting the circumferential wall of the rollers R1, R2 absorbs part of the radiation is admissible insofar as the rollers R1, R2 have time to cool during their rotation.

The complete circumferential wall of the rollers R1, R2 can have this transparency. But as a variant, only part of the circumferential wall of the rollers R1, R2 can have this transparency. For example, with reference to the axial direction of the rolls R1, R2, only a central circumferential strip of the circumferential wall of the rolls R1, R2 which is preferably as wide as the stacks E to be treated, can present this transparency continuously on the entire circumference, while the end portions of the circumferential wall on either side of this circumferential strip may be opaque to the radiation from sources UV1, UV2.

If the material of the circumferential wall of the rollers is too hard to directly contact the glass sheets V1, V2 of the stacks E, the circumferential wall of the rollers R1, R2 can be covered with a suitable polymeric material to provide a soft contact with the glass sheets V1, V2.

A polymeric material with a hardness of about 60 shore A is suitable for this purpose. This polymeric material is chosen to also allow the radiation from the UV1 or UV2 source of the corresponding roller to pass at least partially. In particular, it is possible to use PDMS (Polydimethylsiloxane) about 30 mm thick, knowing that it can have a UV transmission rate of around 75% for this thickness.

Of course, materials other than PDMS or other thicknesses of PDMS can be used.

The use of UV LED strips offers the advantage of better process control since the switching on and off of this type of radiation source is extremely fast and can deliver the maximum power in milliseconds, which does not is not the case with IR lamps. Their heating power can be easily adapted to the type of laminated glazing to be deaerated and the system does not need a long warm-up time.

Moreover, since their activation and deactivation are almost instantaneous, it is possible to select the area of illumination of a given E-stack. In particular, it is possible to seal only the edges of an E-stack. For example, it suffices to activate all the UV LEDs along the length of the UV LED strip in order to heat the entire front edge of the E-stack which is perpendicular to the direction of scrolling X and the same then for its trailing edge. On the contrary, between the leading edge and the trailing edge, only UV LEDs can be activated towards the longitudinal ends of the strip of UV LEDs for the entire length of the stack E which is parallel to the running direction X, which limits the heating only at the side edges of the thermoplastic sheet T of the stack E which are parallel to the running direction X.

There represents an enlarged view in the zone of pressing of the roll R1 on the glass sheet V1 of a stack E during its passage between the rolls R1 and R2, the observation being made in the direction of the axes of rotation of the rolls R1 and R2 as in . As can be seen, the contact zone Zc of roller R1 on glass sheet V1 has a certain length Lc in the running direction X due to the flexibility of the material on the outside of roller R1. In practice, the length Lc is generally of the order of a few centimeters, for example 5 cm, and which depends on the hardness of the coating of the rollers R1, R2, on the pressing force which is applied, as well as on their diameter. . The radiation from the UV1 source reaches the outer surface of the glass sheet V1 in an impact zone Zuv having a length Luv in the running direction X.

It is preferable for the impact zone Zuv to be totally or partially included in the contact zone Zc, which makes it possible to favor the concomitance between the pressing and the fact that the thermoplastic sheet becomes adhesive under the effect of the heating. In particular, it is preferable that at least 10%, more preferably at least 20%, of the impact zone Zuv be included in the contact zone Zc. It is even more preferable that the fictitious plane P defined by the axes of rotation of the first and second rollers R1, R2 – cf. - cuts the Zuv impact zone. More advantageously still, the fictitious plane P intersects the impact zone Zuv in its middle as illustrated by the . It will be understood that the length Luv of the impact zone Zuv may be less than the length Lc of the contact zone Zc as is the case in the . As a variant, the length Luv can be equal to the length Lc, or else the length Luv can be greater than the length Lc.

The radiation intensity of the source UV1, the length of the impact zone Zuv and the running speed of the stacks E between the rollers R1, R2 in the running direction X are chosen so that the thermoplastic sheet T made of PVB or another reaches the desired surface temperature at the interface with the glass sheet V1 to make it adhesive so that the pressing operated by the rollers R1, R2 causes the thermoplastic sheet to adhere to the glass sheet V1. The running speed of the stacks E between the rollers R1, R2 is preferably selected so that a stack E is locally subjected to radiation from the first radiation source UV1 for an exposure time of less than 2 seconds, preferably less than 1 second, more preferably less than 0.5 second and more preferably still less than 0.25 second, or even less than 0.2 second. The intensity of the radiation from the UV1 source is chosen accordingly to locally heat the thermoplastic sheet T at its interface with the glass sheet V1 during the exposure time to the point of making it locally adhesive at this interface and allowing the pressing to the stack E by the rollers R1, R2 to cause the thermoplastic sheet T to adhere locally to the glass sheet V1 .

Of course, the above considerations concerning the impact zone Zuv with respect to the contact zone Zc, as well as concerning the intensity of the radiation are also applicable with regard to the source UV2 and the roller R2 with respect to the sheet glass V2. These considerations also apply to the variant which will now be described with reference to the and 16.

There represents a variant of the deaeration station 7 of the . The only difference concerns the structure of the roller R1 which is now referenced R1a. It will be understood that the roller R2 can also be replaced by a roller similar to the roller R1a.

The material of the circumferential wall of roller R1a is opaque to radiation from source UV1. But to allow its radiation to pass, the roller R1a is provided with through openings distributed over the circumference of the circumferential wall. In this case, it is slots 12 extending axially as shown in the top view of the . The slots 12 can be interrupted once, as illustrated, or several times in the axial direction in order to confer satisfactory mechanical strength on the roller R1a. In other words, there may each time be a succession of slots in the axial direction.

Source UV1 can still be active. In this case, the opaque segments of roller R1a will periodically block the radiation as roller R1a rotates. In order to at least partially recycle this radiation, the opaque segments of the roller R1a can be provided with an inclined reflective surface so as to reflect the radiation towards the adjacent slot 12 which is located substantially opposite the stack E.

Alternatively, the UV1 source can be activated just when a slot 12 is in its alignment in order to radiate directly towards the stack E passing between the rollers R1a, R2. This is possible, since UV LEDs are very fast sources and can reach maximum power in less than 1ms. In addition, since UV LEDs only age when current passes through them, this flashing mode of operation increases their lifespan and avoids thermal losses.

If necessary, the slots 12 pass through both the first layer of rigid material and the second layer of flexible material which together form the circumferential wall of the roller R1a. As a variant, the slots 12 only pass through the first opaque layer while the second layer covers the first layer as well as the slots 12 formed in the latter. In this case, the material of the second layer is chosen to allow the radiation from the UV1 source to pass at least partially.

Numerous variants are possible concerning the structure of the radiation passage openings which are made in the circumferential wall of the roller R1a. For example, the slots 12 can each extend in a respective radial plane of the roller R1a or even helically in the axial direction. According to another variant, the openings are made in a circular manner, being distributed over the entire surface of the peripheral wall.

Of course, the present invention is not limited to the examples and to the embodiment described and represented, but it is capable of numerous variants accessible to those skilled in the art.

For example, the interlayer thermoplastic adhesive sheet may be different from a PVB sheet. It may in particular be sheets of polyurethane (PU), of ethylene-vinyl acetate (EVA), of ionomer such as partially neutralized poly(acrylic acid), for example marketed under the registered trademark SentryGlas® by the company Kuraray alone or in mixtures of several of them. These polymeric materials can include variable contents of plasticizers, and consist of varieties with sound attenuation / insulation properties.

According to a variant of the embodiment of the , provision may be made for the UV LED strip UV1 to be replaced by a plurality of such strips fixed side by side over the entire circumference of the circumferential wall inside the roller R1, R2 concerned, each strip extending for example along the axial direction. In this case, the UV LED strips rotate with the roller R1, R2 concerned. The appropriate LEDs of each strip are then preferentially activated when it faces the stack E whereas they are all deactivated otherwise as the roller R1, R2 concerned rotates.

According to another variant, the deaeration station 7 can comprise two pairs of successive rollers R1, R2 with a single roller of each pair R1, R2 which is provided with a radiation source and the two rollers provided with a radiation source being arranged on a respective side relative to the stacks E which scroll between the two pairs of rollers R1, R2. Thus, each of the pairs of rollers is dedicated to binding and deaerating the thermoplastic sheet T with respect to a respective one of glass sheets V1, V2.

According to another variant, the UV1 or UV2 radiation sources are not constituted by one or more bands of UV LEDs, but by UV lasers. According to another variant, they are replaced by LEDs or lasers or other appropriate sources emitting in the wavelength band between 1.6 and 2.9 μm and more preferably between 2.2 and 2.7 μm, and with a spectral width of at most 500 nm, more preferably at most 250 nm, and even more preferably at most 100 nm. According to another variant, they are replaced by microwave transmitters, for example between 915 MHz and 2.45 GHz or else radio frequency transmitters, for example between 10 and 40 MHz, this type of source being able, depending on the case, also to be adapted to heat the interlayer thermoplastic sheet. Of course, if necessary, the circumferential wall of the rollers R1, R2 is adapted in particular in terms of material to allow the radiation from the selected sources to pass at least partially.

Claims (18)

Device (7) for adhesively bonding two sheets of glass (V1, V2) to a thermoplastic sheet (T) which becomes adhesive by heating, which sheets are arranged beforehand in the form of a stack (E) in which the thermoplastic sheet is interposed between the two sheets of glass in direct contact with them, the device comprising:

• at least a first radiation source (UV1) to heat the thermoplastic sheet (T) within the stack (E) so as to make it adhesive, and
• a first roller (R1) and a second roller (R2) mounted for rotation to press the stack (E) between them as it passes between them so as to cause the thermoplastic sheet (T) made adhesive by the first radiation source (UV1) to at least one of the glass sheets (V1, V2),

in which :

• the first radiation source (UV1) is arranged inside the first roller (R1), and
• the circumferential wall of the first roller (R1) is adapted to let the radiation from the first radiation source (UV1) pass at least partially so as to reach the stack (E) during its passage between the two rollers (R1, R2 ).

Device according to Claim 1, comprising at least one second source of radiation (UV2) for heating, within the stack (E), the thermoplastic sheet (T) so as to make it adhesive, in which:

• the second radiation source (UV2) is arranged inside the second roller (R2), and
• the peripheral wall of the second roller (R2) is adapted to allow the radiation from the second radiation source (UV2) to pass at least partially so as to reach the stack (E) during its passage between the two rollers (R1, R2 ).

Device according to Claim 1 or 2, in which at least a part of the circumferential wall of the first and/or of the second roller (R1, R2) has a transparency allowing the radiation of the corresponding radiation source to pass at least partially through the roller in question, said part preferably extending continuously over the entire circumference of the roller in question, and in which, preferably, the transmission rate of said part of the circumferential wall is at least 50% and more preferably at minus 70% for a given wavelength or range of wavelengths included in the radiation from the corresponding radiation source. Device according to Claim 1 or 2, in which the peripheral wall of the first and/or of the second roller has openings (12) distributed circumferentially to allow the radiation from the corresponding radiation source to pass, the peripheral wall preferably being opaque to the radiation. of the corresponding radiation source outside the openings (12) and at least part of the openings (12) being preferably made in the form of slots. Device according to Claim 4, in which reflecting surfaces are arranged on the circumferential wall of the inner side of the roller between successive openings (12) in the circumferential direction to reflect the radiation from the corresponding radiation source towards an adjacent opening (12). . Device according to Claim 4 or 5, in which the openings (12) of the circumferential wall pass through so that the radiation from the corresponding radiation source can follow a path free of material as far as the stack (E). Device according to one of Claims 4 or 5, in which the circumferential wall comprises:

• a first thickness of material opaque to the radiation of the corresponding radiation source, and
• a second thickness of material having a transparency allowing the radiation from the corresponding radiation source to pass at least partially,

wherein the openings (12) pass only through the first thickness of material and are covered by the second thickness of material. Device according to any one of Claims 5 to 7, comprising a circuit for controlling the first and/or the second radiation source (UV1, UV2) to activate it when an opening (12) in the circumferential wall of the corresponding roller is located in the radiation path of the radiation source and to deactivate it when an opaque portion of the circumferential wall of the corresponding roller is located in the radiation path of the radiation source. Device according to any one of Claims 1 to 8, in which the first and/or the second radiation source (UV1, UV2) is of directional radiation and is arranged inside the corresponding roller (R1; R2) in such a way independent of the rotation of the roller so that, in use, the radiation from the radiation source reaches in a fixed direction the stack (E) during its passage between the first roller (R1) and the second roller (R2). Device according to any one of Claims 1 to 9, in which, with reference to the direction of passage (X) of the stack between the first roller (R1) and the second roller (R2), the impact zone ( Zuv) of the radiation from the first and/or the second radiation source (UV1, UV2) on the stack (E) during its passage between the first and second rollers (R1, R2) is at least partially included in the contact zone (Zc) of the roller (R1; R2) corresponding to the stack (E) and, more preferentially, at least 10%, more preferentially still at least 20% of the impact zone (Zuv) of the radiation of the first and/or the second radiation source (UV1, UV2) on the stack (E) is included in the contact zone (Zc) of the roller (R1, R2) corresponding with reference to the direction of passage (X ) of the stack (E) between the first roller (R1) and the second roller (R2). Device according to any one of Claims 1 to 10, in which, with reference to the direction of passage (X) of the stack between the first roller (R1) and the second roller (R2), the fictitious plane (P) defined by the axes of rotation of the first and second rollers (R1, R2) intersects the impact zone (Zuv) of the radiation from the first and/or the second radiation source (UV1, UV2) on the stack (E ) as it passes between the first roller (R1) and the second roller (R2), the fictitious plane (P) preferentially intersecting the impact zone (Zuv) in its middle. Device according to any one of Claims 1 to 11, in which the first and/or the second radiation source is:

• a UV source of wavelengths between 340 and 450 nm, and more preferably between 340 and 400 nm, or else
• a source of infrared radiation with wavelengths between 1.6 and 2.9 μm, more preferably between 2.2 and 2.7 μm, and with a spectral width of at most 500 nm, more preferably at more than 250 nm, and more preferably still at most 100 nm.

Process for manufacturing laminated glazing from two sheets of glass (V1, V2) and a thermoplastic sheet (T) which becomes adhesive by heating, comprising the steps consisting in:

• providing the two sheets of glass and the thermoplastic sheet in the form of a stack (E) in which the thermoplastic sheet (T) is interposed between the two sheets of glass (V1, V2) in direct contact with them, and
• scroll the stack (E) between the first roller (R1) and the second roller (R2) of a device (7) according to any one of claims 1 to 12 to press between them the stack (E) at the as it passes between them,

in which :

• the first and/or the second radiation source (UV1, UV2) of the device (7) are activated at least during the passage of the stack (E) between the first and second rollers (R1, R2) to heat the thermoplastic sheet (T) within the stack (E) so as to make it adhesive, and
• the first roller (R1) and the second roller (R2) of the device (7) press the stack (E) together as it passes between them to cause the thermoplastic sheet (T) made adhesive by the first and/or second radiation source (UV1, UV2) to one and/or the other of the glass sheets.

Method according to Claim 13, in which the first and/or the second radiation source (UV1, UV2) are selected in such a way that:

• the glass sheet (V1; V2) arranged on the side of the first roller (R1), respectively on the side of the second roller (R2), has a transmission rate of at least 50%, more preferably of at least 75%, and even more preferably by at least 85% with respect to the part of the radiation from the radiation source considered which reaches the stack (E), and
• the thermoplastic sheet (T) has an absorption rate of at least 50%, more preferably at least 75%, and even more preferably at least 85% with respect to the part of the radiation of the considered radiation source which reaches the thermoplastic sheet (T) after having passed through the glass sheet (V1; V2) on the side of the first roller (R1), respectively on the side of the second roller (R2).

Method according to claim 13 or 14, in which the first roller (R1) and the second roller (R2) exert a level of pressure on the stack (E) as it passes between them which is sufficiently high to eliminate a major part of the air present between the thermoplastic sheet and the glass sheets. Process according to any one of Claims 13 to 15, in which the pressure applied by the first roller (R1) and the second roller (R2) on the stack (E) is between 0.1 and 1 MPa, limits included. Method according to any one of Claims 13 to 16, in which the running speed of the stack (E) between the first roll (R1) and the second roll (R2) is selected so that the stack (E) is locally subjected to radiation from the first and/or second radiation source (UV1, UV2) for an exposure time of less than 2 seconds, preferably less than 1 second, more preferably less than 0.5 second and more preferably even less than 0.25 seconds, or even less than 0.2 seconds, the intensity of the radiation from the first and/or the second radiation source (UV1, UV2) being chosen to locally heat the thermoplastic sheet (T) to its interface with the glass sheet (V1; V2) located on the side corresponding to the radiation source considered during the exposure time to the point of making the thermoplastic sheet (T) locally adhesive at this interface and allowing the pressing of the stacking (E) by the first roller (R1) and the second roller (R2) to locally adhere the thermoplastic sheet (T) to this glass sheet (V1; V2) . Method according to any one of claims 13 to 17, further comprising a step of treating the stack (E) in an autoclave after passing the stack (E) between the first roller (R1) and the second roller (R2 ).