Glass recycling process

Abstract

TITLE: Glazing Recycling Method The present invention relates to a glazing recycling method (1) comprising components made of non-glass material. The method comprises a glazing breaking step, followed by a sorting step of the glazing fragments (100) (1) to separate the glazing fragments (100) (1) associated with a substantial amount of the non-glass material from the glazing fragments not associated with a substantial amount of the non-glass material. According to the invention, the method includes a preliminary step, prior to the glazing breaking step (1), of bonding at least one unbreakable component (31, 32) to a portion of the glazing surface (1), in the areas of the glazing associated with the components made of non-glass material. The sorting step is carried out by removing the unbreakable component(s) (31, 32) from the glazing fragments (100) (1), along with the glazing fragments (100) (1) bonded to them.Abbreviated figure: Figure 4.

Description

Title of the invention: Process for recycling glazing Field of invention

[0001] The present invention relates to the recycling of flat glass panes.

[0002] In particular, the invention relates to the recycling of glazing composed of a glass substrate on which a component made of non-glass material is assembled. Prior art

[0003] Glass is generally manufactured by melting raw materials containing silica. It is also possible to produce it by melting pieces of recycled glass. This process using recycled glass requires less energy to produce the same quantity of glass than the process requiring the melting of raw materials and their transformation to form the desired glass composition. Manufacturing glass from recycled glass is therefore particularly advantageous and has a lower CO2 impact.

[0004] To manufacture glass from recycled glass, it is necessary to have recycled glass with the desired chemical composition for the glass to be manufactured. A particular difficulty arises when recycling objects composed of both glass and components made of a non-glass material. If these components are infusible, they may float on the molten glass and must be removed. If, on the other hand, these components are fusible at the melting temperature of glass, they risk melting along with the recycled glass and mixing with it, altering its chemical composition, or even chemically interacting with the molten glass or the tin bath. It is therefore generally not desirable to recycle such objects composed of both glass and fusible non-glass components.

[0005] Such a difficulty can arise, in particular, for the recycling of automotive glazing, and especially vehicle rear windows. Vehicle rear windows most often include a defrosting element made up of electrically conductive tracks deposited on one side of the rear window's glass substrate. These tracks are often formed from an electrically conductive silver paste, which is screen-printed onto the glass substrate and solidified by high-temperature curing. When the vehicle is in use, an electric current can pass through these tracks to heat them up and enable the rear window to be demisted or defrosted.Typically, on a rear window, the defrosting resistor consists of thin tracks offering high electrical resistance, allowing the rear window to be defrosted or defogged, and thick tracks, offering less electrical resistance, which ensure the connection. electric fine tracks.

[0006] Such defrosting resistors can also be provided on vehicle windscreens or, in certain cases, on vehicle side windows.

[0007] Recycling such vehicle glazing poses a problem, as the metallic material contained in the defrosting element is likely to melt with the recycled glass, altering its composition in an unacceptable way or impairing the properties of the tin bath.

[0008] To enable the recycling of glass substrates from vehicle rear windows, documents such as US20200165697A1, WO2009087908A1, US2022228235, and WO2020240126 are known, describing chemical processes for dissociating a metallic component from the glass to which it is bonded. However, subjecting an entire rear window to such a separation process is not very efficient.

[0009] It is also known to sort pieces of glass according to whether or not they are associated with components made of non-glass material. Such sorting is, however, complicated and expensive.

[0010] The present invention aims to overcome these drawbacks of the prior art.

[0011] In particular, the invention aims to provide a glass recycling process enabling optimized recycling of flat glass panes composed of a glass substrate onto which a non-glass component is assembled.

[0012] A particular objective of the invention is to enable the optimized recycling of automotive glazing, and in particular of the rear windows of motor vehicles equipped with defrosting resistors comprising metallic materials.

[0013] Yet another objective of the invention is to propose such a recycling process which allows the production of recycled glass, which has chemical characteristics as close as possible to those desired.

[0014] Yet another objective of the invention is to provide such a recycling process which is easy to implement. Statement of the invention

[0015] These objectives, as well as others that will become clearer later, are achieved using a glazing recycling process comprising a glass substrate and at least one non-glass material component bonded to the glass substrate. This process includes a glass breaking step, followed by a glass fragment separation step, to separate the glass fragments bonded to a substantial amount of the non-glass material from the glass fragments not bonded to a substantial amount of the non-glass material. According to the invention, this process includes a preliminary step, prior to the glass breaking step, of bonding on a part of the surface of the glazing of at least one non-breakable component, at the level of at least one area of ​​the glazing to which at least one of the components in non-glass material is bonded, and the separation step includes the separation of the non-breakable components, with the pieces of glazing that are glued to them, from the other pieces of glazing that are not glued to the non-breakable component.

[0016] Advantageously, the glazing is automotive glazing.

[0017] Advantageously, the glazing is a rear window of a motor vehicle, including a defrosting resistor constituting one of the components made of non-glass material.

[0018] According to an advantageous embodiment, the non-glass material component is a screen-printed component on the glass substrate, to form said glazing.

[0019] Preferably, the non-glass component comprises a metallic alloy screen-printed on the glass substrate.

[0020] According to an advantageous embodiment, the non-breakable component is a flexible adhesive film.

[0021] Preferably, this flexible adhesive film is made of plastic material.

[0022] According to a preferred embodiment, the unbreakable component is glued onto a face of said glass substrate to which the non-glass material component is attached.

[0023] According to another possible embodiment, one of the non-breakable components is glued to each of the two opposite faces of the glass substrate, at the level of at least one of the areas of the glazing on which at least one of the components made of non-glass material is bonded. Description of the figures

[0024] The invention will be better understood upon reading the following description of preferred embodiments, given by way of simple figurative and non-limiting example, and accompanied by the figures, among which: - Fig. 1 represents a window forming a rear window of a motor vehicle. - Fig. 2 represents the glazing of Fig. 1 after it has been broken. - Figure 3 shows the glazing of Figure 1 onto which some have been glued non-breakable adhesive components, according to an embodiment of the process of the invention. - Fig. 4 represents the glazing of Fig. 3, onto which the unbreakable adhesive components were glued, after it had been broken. - Fig. 5 represents the unbreakable adhesive components and the fragments of the glazing from Fig. 4 that adhere to it. - Fig. 6 is a graphic showing the steps of a recycling process according to one embodiment of the invention. Description of the embodiments

[0025] Fig. 1 represents, in front view, a glazing 1 constituting a rear window of a motor vehicle.

[0026] Automotive vehicle glazing, such as windshields or rear windows, may consist of several glass substrates layered one on top of the other, between which layers of non-glass materials, such as plastics, may be intercalated. The term "glazing" used in this description preferably applies to a single glass substrate. However, it may also apply to a composite assembly comprising several superimposed glass substrates.

[0027] The glazing 1 is formed of a glass substrate 10, on which components made of non-glass material are bonded.

[0028] A glass substrate, as defined in this description, is a flat glass plate made of a glass material, that is, a non-crystalline solid material exhibiting the glass transition phenomenon. Preferably, this glass substrate is transparent, meaning that it allows specular transmission of radiation at least in the wavelength ranges useful for the intended application of the element. In this case, glass substrates used as automotive glazing are normally transparent at least in the visible wavelength range. The glass substrate may also be coated with components such as enamels, which may themselves be made of a glass material that does not impede the recycling of the glass substrate.

[0029] Non-glass material components, within the meaning of this description, are components that are not formed mainly or essentially of a glass material, which can be bonded to a glass substrate.

[0030] The glass substrate can, in a known manner, be covered on one or both faces with a thin coating. Such a coating, which may be made of a non-glass material, is generally very thin, and its mass therefore constitutes only a tiny proportion of the total mass of the glazing. The small proportion of non-glass material that such a coating contributes to a glazing unit is generally not considered to be an obstacle to the recycling of that glazing.

[0031] In the embodiment shown, components made of non-glass material constitute a defrosting resistor 2, formed of electrically conductive tracks deposited on one face of the glass substrate. These tracks are formed by a electrically conductive material, which is deposited for example by screen printing on the glass substrate and solidified and bonded to the glass substrate by high-temperature baking.

[0032] The mass of such a non-glass component remains small compared to the total mass of the glazing. However, it is significant enough to affect the recycling conditions of this glazing. For example, glazing comprising a glass substrate and a non-glass component may be considered to contain a significant amount of non-glass material when the mass of this non-glass component represents more than 200 ppm (parts per million) of the total mass of the glazing. Such a definition is, however, only indicative and may vary, for example, depending on the recycling process used.

[0033] The electrically conductive material used in the defrosting heater 2 can be a partially metallic alloy which, in the illustrated embodiment, comprises a mixture of at least 80% silver and a glass frit, which facilitates its adhesion to the glass substrate. This coating thus has high hardness and cannot be easily removed from the glass substrate.

[0034] Conventionally, the defrosting resistor 2 of the glazing 1 is composed of thin tracks offering high electrical resistance and thick tracks offering lower electrical resistance. The thick tracks form the lateral collectors 21, 22, and 23, located along two lateral edges of the glass substrate. The lateral collector 21, situated along one edge, is connected to the lateral collectors 22 and 23, located along the other edge, by a plurality of thin tracks forming the heating wires 24.

[0035] The lateral collectors 21, 22 and 23 are designed to ensure efficient conduction of the electric current, without offering significant resistance. These collectors therefore have large dimensions, using a relatively large quantity of non-glass material.

[0036] On the contrary, the heating wires 24 are designed to heat up when an electric current passes through them. They must therefore offer high resistance and consequently have a very small cross-section. These heating wires 24 are therefore made up of a very small amount of non-glass material.

[0037] A large part of the non-glass material used to form the defrosting resistance 2 is therefore placed in the collectors 21, 22 and 23. Although the heating wires 24 cover a larger area of ​​the glazing 1, the mass of non-glass material they use is, on the contrary, relatively small.

[0038] To recycle the glazing 1, it is necessary to break it to melt the pieces. Figure 2 thus represents the glazing 1 of Figure 1 broken into 100 pieces. Among these 100 pieces, the vast majority consists solely of glass material, or contains only a very small proportion of non-glass material associated with the glass material. On the contrary, the pieces 100 corresponding to the parts of the glazing 1 including the collectors 21, 22 and 23 have a more significant proportion of non-glass material.

[0039] Treating all the glass fragments 100 to separate the non-glass material from the glass material would be inefficient. Effective glass recycling would require separating the fragments 100 composed exclusively or almost exclusively of glass material, which can be recycled directly, from the fragments 100 containing a significant proportion of non-glass material, which can undergo treatment to separate the glass material from the non-glass material. However, such sorting of the fragments 100 is very complicated and costly.

[0040] To facilitate the separation of the pieces of glass 100 composed exclusively or almost exclusively of glass material from the pieces 100 comprising a significant part of non-glass materials, the invention proposes a particular glass recycling process.

[0041] According to the invention, the glass recycling process comprises, prior to a step 92 of breaking the glass, a preliminary step 91 of bonding unbreakable components to a portion of the glass surface. An unbreakable component, as defined in this description, is a component that can be attached to a glass pane and does not break when the glass is broken. Such an unbreakable component may be a rigid component, for example, metallic, with mechanical properties that prevent it from breaking under the effect of an impact that shatters the glass. It may also be made of a flexible material, such as a plastic film, capable of deforming without breaking under the effect of an impact that shatters the glass.

[0042] According to other possible embodiments of the invention, the bonding of a shatterproof component to a portion of the glazing surface can be achieved by depositing, on a portion of the glazing surface, a liquid component that solidifies after deposition, such as, for example, an organic resin or a plastic coating. This liquid component constitutes a shatterproof component within the meaning of the present invention if, after its solidification and after the glazing breaks, it is capable of retaining the shards of glazing to which it is bonded.

[0043] According to the invention, the shatterproof component is bonded only to a portion of the glazing surface, in order to allow for separate recycling of the glazing sections bonded to a shatterproof component and the glazing sections not bonded to a shatterproof component. It is particularly advantageous for the shatterproof component(s) to be bonded to only a portion of the surface of one face of the glazing, less than 50% of the total surface area of ​​that face, and even preferably less than 10% of the total surface area of ​​that face.

[0044] Figure 3 represents the glazing 1 on which such components made of non-material breakable materials have been applied. In this case, these components made of non-breakable material consist of portions of adhesive film 31 and 32, such as adhesive tape, which are glued onto one face of the glazing 1, at the level of the collectors 21, 22 and 23.

[0045] More specifically, a portion of adhesive film 31 is glued to a face of the glazing 1, on an area of ​​this glazing 1 to which the collector 21 is attached, and a portion of adhesive film 32 is placed on a face of the glazing 1, on an area of ​​this glazing 1 to which the collectors 22 and 23 are attached. These portions of adhesive film 31 and 32, constituting unbreakable components, therefore cover the areas of the glazing 1 to which significant quantities of non-glass material are attached.

[0046] In the embodiment shown, it has indeed been chosen to only glue the components made of unbreakable material onto the areas of the glazing 1 to which the collectors 21, 22 and 23 are attached, which concentrate a large part of the non-glass materials of the glazing 1, and not to glue them onto the heating wires 24. It would also be possible, in a variant of this embodiment, to glue components made of unbreakable material onto all the areas of the glazing 1 at which the non-glass components are attached, that is to say on the areas of this glazing 1 to which the collectors 21, 22 and 23 are attached as well as on the areas of this glazing 1 to which the heating wires 24 are attached.

[0047] According to the invention, the shatterproof components can be bonded to one or both faces of the glazing 1, specifically to the portions of this glazing that contain a significant amount of non-glass components. In the preferred embodiment shown, however, the portions of adhesive film 31 and 32 constituting the shatterproof components are bonded to the face of the glazing 1 that contains the non-glass material deposits. Bonding the shatterproof components to this face allows for a more precise definition of the areas of the glazing that contain a significant amount of non-glass components, onto which the shatterproof component can be bonded.

[0048] Following step 91 of bonding non-shatterable components to the glazing 1, the recycling process according to the invention includes a step 92 of breaking the glazing. The glazing 1 can thus be reduced to pieces 100, as shown in [Fig. 4]. This breaking of the glazing does not cause breakage or separation of the non-shatterable components formed by the portions of adhesive film 31 and 32, which remain attached to the pieces of glazing to which they were bonded.

[0049] After this step 92 of breaking the glazing 1, the process according to the invention implements a step 93 of separating the pieces 100 of the glazing 1 associated with the non-breakable components, on the one hand, and the pieces 100 of the glazing 1 which are not associated with the non-breakable components, on the other hand.

[0050] Such a separation can be made very easily. It can, for example, be done by removal of the unbreakable materials, along with the associated pieces of glass 100. It is thus possible, on the broken glazing 1 shown in [Fig. 4], to remove the portions of adhesive film 31 and 32, along with the pieces of glass 100 that are stuck to them.

[0051] According to another possible embodiment, this separation step 93 can also be carried out by sieving the pieces of glass 100. The pieces 100 which are not associated with unbreakable components then pass through the mesh of the sieve, while the unbreakable components, as well as the pieces which are stuck to them, do not pass through these meshes.

[0052] Figure 5 thus shows the portions of adhesive film 31 and 32, constituting unbreakable components, bonded to the pieces 100 of the portion of the glazing 1 to which they were bonded. These pieces 100 are advantageously those which carry the portions of the collectors 21, 22 and 23, comprising a significant proportion of non-glass material.

[0053] These pieces 100 bonded to the non-breakable components can undergo specific recycling during a reuse step 94. For example, they can be melted to form a glass material whose composition may include the non-glass material. Alternatively, they can undergo recycling steps aimed at separating the glass material from the non-glass material, for separate recycling.

[0054] On the contrary, the pieces of the glazing 1 which are not glued to these portions of adhesive film 31 and 32 do not include any non-glass material, or include only a small part thereof, corresponding in particular to portions of the heating wires 24. These materials can advantageously be recycled as glass not including any non-glass material, during a reuse step 95.

[0055] Separating the glazing pieces 100, as defined in the present invention, does not necessarily mean that all the glazing pieces bonded to the shatterproof material are associated with non-glass materials, nor that all the glazing pieces not bonded to the shatterproof material are free of non-glass materials. However, it does allow, very easily, the concentration of the glazing pieces associated with the largest quantities of non-glass material.

[0056] Thus, by way of example, the inventors applied a recycling process according to an embodiment of the invention to a rear window of a motor vehicle, which is composed of a glass substrate to which a defrosting element made of a silver alloy is attached. The glass substrate has a mass of approximately 5 kg. The defrosting element is formed of a silver alloy weighing approximately 1.3 g, distributed between the side collectors and the heating wires. The silver alloy therefore represents approximately 0.0265% of the mass of the glazing, or 265 ppm (parts per million).

[0057] Applying the recycling process described in the figures to this rear window, in which components made of unbreakable material are bonded only to the areas of the glazing to which the collectors are attached, makes it easy to separate the pieces of this glazing into a first part, weighing approximately 4,750 g, which contains only about 170 ppm of silver alloy, and a second part, weighing approximately 250 g, which contains 2,000 ppm of silver alloy. These two parts can advantageously be recycled separately.

[0058] Applying to this rear window a variant of the recycling process described in the figures, in which components made of unbreakable material are bonded to all areas of the glazing to which the collectors and conductive wires are attached, makes it easy to separate the pieces of this glazing into a first part, weighing approximately 3,950 g, which contains no silver alloy at all, and a second part, weighing approximately 1,050 g, which contains 1,260 ppm of silver alloy. These two parts can advantageously be recycled separately.

Claims

Claims

1. Method for recycling a glazing unit (1) comprising a glass substrate (10) and at least one component made of non-glass material (2) secured to said glass substrate (10), said method comprising a step (92) of breaking said glazing unit (1), followed by a step (93) of separating the pieces of said glazing unit, to separate the pieces (100) of said glazing unit (1) secured to a substantial quantity of said non-glass material, from the pieces (100) of said glazing unit (1) which are not secured to a substantial quantity of said non-glass material, characterized in that it comprises a preliminary step (91), before the step (92) of breaking said glazing unit (1), of bonding to a portion of the surface of said glazing unit (1) at least one non-breakable component (31, 32), at at least one area of said glazing unit (1) on which at least one of said components made of non-glass material (2) is secured,and in that said separation step (93) comprises separating said non-breakable components (31, 32), with the pieces (100) of said glazing (1) which are bonded thereto, from the other pieces (100) of said glazing (1) which are not bonded to said non-breakable components (31, 32).,

2. Recycling method according to the preceding claim, characterized in that said glazing (1) is automotive glazing.

3. Recycling method according to the preceding claim, characterized in that said glazing (1) is a rear window of a motor vehicle, comprising a defrosting resistor (2) constituting one of said components made of non-glass material.

4. Recycling method according to any one of the preceding claims, characterized in that said non-glass material component (2) is a component screen-printed on said glass substrate (10), to form said glazing (1).

5. Recycling method according to any one of the preceding claims, characterized in that said non-glass component (2) comprises a metal alloy screen-printed on said glass substrate (10).

6. A recycling method according to any one of the preceding claims, characterized in that said non-breakable component (31, 32) is a flexible adhesive film.

7. Recycling method according to claim 6, characterized in that said flexible adhesive film (31, 32) is made of plastic material.

8. Recycling method according to any one of claims 1 to 6, characterized in that said non-breakable component (31, 32) is bonded to a face of said glass substrate (10) on which said component made of non-glass material (2) is secured.

9. Recycling method according to any one of claims 1 to 6, characterized in that one of said non-breakable components (31, 32) is bonded to each of the two opposite faces of said glass substrate (10), at least in one area of said glazing (1) on which at least one of said components made of non-glass material (2) is secured.

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