CN115151416A

CN115151416A - Composite glass sheet and method of manufacturing a composite glass sheet

Info

Publication number: CN115151416A
Application number: CN202280000708.XA
Authority: CN
Inventors: A·帕尔芒捷; V·舒尔茨
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2021-01-29
Filing date: 2022-01-19
Publication date: 2022-10-04
Also published as: WO2022161821A1

Abstract

The invention relates to a method for producing a composite glass pane (1), wherein: (a) providing a layer sequence comprising the following order: -a first protective layer (11), -a functional layer (6) arranged on the first protective layer (11), -an inner thermoplastic composite film (5) arranged on the functional layer (6), -and a second protective layer (12) arranged on the inner thermoplastic composite film (5), (b) removing the first protective layer (11) from the functional layer (6), (c) applying the outer thermoplastic composite film (4) onto the functional layer (6), (d) removing the second protective layer (12) from the inner thermoplastic composite film (5) with supply of ionized air (13), and arranging an outer glass pane (2) on the outer thermoplastic composite film (4) and an inner glass pane (3) on the inner thermoplastic composite film (5) in a stack to form a layer, and (e) laminating the layer stack obtained from method step (d) to form a composite glass pane (1).

Description

Composite glass pane and method for producing a composite glass pane

The present invention relates to a method of manufacturing a composite glass sheet. The invention also relates to a composite glass pane and to the use thereof.

Head-up displays (HUDs) are currently frequently used in vehicles and aircraft. The operating principle of the HUD is implemented here by using an imaging unit which projects an image using an optical module and a projection surface, which image is perceived by the driver as a virtual image. If this image is reflected, for example, by a windscreen panel as projection surface, important information can be displayed for the user, which significantly improves the traffic safety.

The windscreen panel consists of two glass sheets joined to each other by a thermoplastic layer. If the windscreen panel shall be equipped with a special function, which is for example absorbing infrared light, reflecting polarized or infrared light, conducting or for aesthetic purposes, it is advantageous to use a functional interlayer or functional element. Composite glasses using multilayer composite layers are known from WO 2018/010865 A1, WO 2018/082920 A1 and WO 2020/094422 A1.

The thermoplastic layers used may consist of polyvinyl butyral (PVB) and be applied to the functional interlayer in different thicknesses. In order not to impair the optical quality of the composite glass pane, the thermoplastic layer used must be thinner than in the composite glasses used according to the standards. The composite glass used according to the standard has a thermoplastic layer thickness of 0.38 mm or 0.76 mm.

WO 2020/017502 A1 discloses a composite glass sheet having an interlayer between an outer glass sheet and an inner glass sheet, which are joined by a thermoplastic layer, preferably PVB. Since a too thick thermoplastic layer at the intermediate layer leads to interference with the HUD image, it is desirable to apply the adhesive layer as thin as possible. However, if the adhesive layer is applied too thinly, insufficient embossing required for venting may result. This can result in poor quality composite glass. To solve this problem, an adhesive layer having a suitable thickness of 0.2 to 70 μm is disclosed, which both reduces the interference of HUD images and improves the exhaust gas in the manufacturing process of the laminated composite glass panel.

It is an object of the present invention to provide a laminated composite glass sheet having high optical quality. The invention also aims to provide a manufacturing method and application thereof.

According to the invention, the object of the invention is achieved by a method for manufacturing a composite glass sheet according to independent claim 1. The object is further achieved by the independent claims 13 and 15. Preferred embodiments follow from the dependent claims.

The present invention relates to a method of manufacturing a composite glass sheet. The method is divided into a plurality of method steps. In a first method step, a layer sequence is provided. The layer sequence comprises in the following order: the protective layer includes a first protective layer, a functional layer disposed on the first protective layer, an inner thermoplastic composite film disposed on the functional layer, and a second protective layer disposed on the inner thermoplastic composite film. In a second method step, the first protective layer is removed from the functional layer. In a third method step, an outer thermoplastic composite film is applied to the functional layer. In a fourth method step, the second protective layer is removed from the inner thermoplastic composite film, wherein the removal of the second protective layer is carried out with the supply of ionized air. After removing the second protective layer, the outer glass plate is disposed on the outer thermoplastic composite film and the inner glass plate is disposed on the inner thermoplastic composite film to form a layer stack. In a fifth method step, the layer stack obtained from the fourth method step is laminated to form a composite glass sheet.

The layer sequence provided in the first method step preferably consists of layers firmly joined to one another, in particular the functional layer and the inner thermoplastic composite film having been pre-laminated. The first and second protective layers are joined to the other layers of the layer sequence by means of adhesive layers, preferably adhesives. Alternatively, the layer sequences provided may also be loosely joined to one another, so that the individual layers can lie loosely on top of one another.

In a fourth method step, the second protective layer can be stripped from the inner thermoplastic composite film by mechanical or manual operation with supply of ionized air. The second protective layer is preferably stripped in a time range of less than 60.0 seconds, preferably less than 5.0 seconds, in particular less than 3.0 seconds. After peeling off the second protective layer, a stacked body is formed by disposing an outer glass plate on the outer thermoplastic composite film and an inner glass plate on the inner thermoplastic composite film. The arrangement of the stack of layers preferably takes place in less than 10 minutes, particularly preferably in less than 5 minutes, in particular in less than 1 minute.

In a further preferred embodiment, the ionized air is generated in the fourth process step by a comb-or saw-tooth ionizer. The comb-type or saw-tooth type ionizer generates oxygen ions by means of high voltage. These ions may be generated, for example, by ionizing radiation or by so-called corona discharge.

In a further preferred embodiment, the ionized air is generated in the fourth process step by a comb-or saw-tooth ionizer. The air ionized in this way is supplied in a fourth method step by a blowing device. The blowing means preferably comprises a blower.

The composite glass pane is preferably used as a window pane, which is suitable and provided for separating an interior space from an external environment. In the context of the present invention, inner glass sheet refers to the glass sheet of the composite glass sheet facing the interior space, in particular the vehicle interior space. The outer glass sheet refers to the glass sheet facing the outside environment.

The outer and inner glass panes have an outer and an inner space-side surface, respectively, and a peripheral side edge extending therebetween. In the context of the present invention, an outside surface refers to a main surface which is arranged to face the outside environment in the mounted position. In the context of the present invention, the surface of the interior space side refers to the main surface which is provided for facing the interior space in the mounted position. The surface of the inner space side of the outer glass pane and the outer side surface of the inner glass pane face each other and are joined to each other in the composite glass pane by means of a thermoplastic interlayer. The arrangement of the outer thermoplastic composite film, the functional layer, and the inner thermoplastic composite film in this order is referred to as a thermoplastic intermediate layer in the upper and lower aspects of the present invention.

The functional layer has an outer first surface and an inner second surface and a circumferential side edge extending between them. In the context of the present invention, the first surface of the functional layer refers to the surface which is provided for facing the external environment in the mounted position. In the context of the present invention, the second surface of the functional layer refers to a surface which is provided for facing the interior space in the mounted position. A first surface of the functional layer is bonded to the outer thermoplastic composite film and a second surface of the functional layer is bonded to the inner thermoplastic composite film.

The composite glass sheet is described such that the surface on the inner space side of the outer glass sheet and the outer side surface of the inner glass sheet face each other and they are bonded to each other through the thermoplastic interlayer.

It has been shown that without the use of ionized air, the attraction of environmental particles due to stripping of the protective layer can result in contamination of the layer stack. The use of ionized air in the fourth process step prevents electrostatic loading of the layer sequence, thereby reducing the attraction of environmental particles to the inner thermoplastic composite film. By using ionized air with the second protective layer removed, the user is enabled to dispense with the use of smaller ISO class clean rooms, which equates to an economic advantage.

The composite glass sheet according to the invention is manufactured by lamination. The lamination can be carried out by methods known per se. The outer glass sheet, the inner glass sheet, and the thermoplastic interlayer disposed therebetween are laminated to one another, such as by autoclave, vacuum bagging, vacuum ring, calendering, vacuum laminator, or combinations thereof. The joining of the outer glass pane and the inner glass pane is usually carried out here under the influence of heat, vacuum and/or pressure.

In a preferred embodiment variant, the lamination is carried out under a negative pressure of 0.1 bar to 2 bar, preferably 0.5 bar to 1 bar. Very good results were obtained in this pressure range.

In a further preferred embodiment variant, the lamination is carried out by means of an autoclave process at an overpressure of 800 to 15 bar, preferably 10 to 13 bar, in particular about 12 bar. This pressure range has proven to be particularly useful in autoclave processes.

In a further particularly preferred embodiment variant, the lamination is carried out at a temperature of from 120 ℃ to 150 ℃. This temperature is very well suited for lamination, since it is above its glass transition temperature for many thermoplastics.

In a preferred embodiment, the outer thermoplastic composite film and the inner thermoplastic composite film independently of each other comprise at least PVB, ethylene Vinyl Acetate (EVA), polyurethane (PU) or mixtures or copolymers or block polymers thereof, preferably PVB. These materials have proven useful for thermoplastic interlayers in composite glass panels and establish adhesive bonding with glass. Thus, good bonding of the outer and inner glass panes to the thermoplastic functional layer is ensured.

In a preferred embodiment, the outer thermoplastic composite film and/or the inner thermoplastic composite film is free or substantially free of plasticizers. In the context of the present invention, "substantially free of plasticizer" means that the outer thermoplastic composite film and/or the inner thermoplastic composite film contains less than 1% plasticizer. This has the advantage that stiffer thermoplastic composite films can be produced, in particular extruded thinner. In a preferred embodiment, the thermoplastic composite film therefore has as little amount of plasticizer as possible in order to be able to be made as thin as possible.

In a preferred embodiment, the thickness of the outer thermoplastic composite film is from 20 to 2000 μm, preferably from 300 to 1000 μm, particularly preferably from 380 to 900 μm, in particular from 510 to 840 μm. The effect of the intermediate layer in the range described is to facilitate the engagement and the weight.

The outer thermoplastic composite film may be a functional composite film. By "functional composite film" is meant herein an outer thermoplastic composite film having at least one specific function, in particular an acoustic damping function, a coloring function, a solar function or a combination of these functions. In the context of the present invention, "thermoplastic composite film having solar function" means that the thermoplastic composite film absorbs or reflects infrared radiation and/or UV radiation. In the context of the present invention, a functional composite film having solar functionality means that solar radiation is absorbed by the functional composite film. In the context of the present invention, a functional composite film having a coloring function means that the functional composite film has coloring.

The acoustically damped composite membrane is usually characterized by a so-called mechanical impedance measurement (MIM, mechanical impedance measurement). This is a standardized method according to ISO 16940, from which damping can be calculated by measuring the natural frequency. According to today's standards, the acoustic damping composite film to be examined is laminated between two glass plates of thickness 2.1 mm to enable corresponding comparisons with different glass thicknesses. Thus, the skilled person is enabled to select a suitable intermediate layer by means of well known standardized measurement methods.

Mechanical impedance measurements were taken at the earliest one month after the manufacture of the composite glass sheet. Furthermore, the acoustic damping compound film itself was laminated with two glass plates having a thickness of 2.1 mm to form a composite glass plate at the earliest one month after its manufacture. Thereby ensuring that a steady state has been established at the moment of measurement.

It has proven to be particularly advantageous if the outer thermoplastic composite film joining the functional layer to the outer glass pane is designed as an acoustically damped composite film. This results in advantageous acoustic damping properties of the composite glass pane.

In another preferred embodiment of the invention, the thickness of the inner thermoplastic composite film is between 35 μm and 250 μm, preferably between 35 μm and 150 μm, particularly preferably between 35 μm and 100 μm, in particular between 35 μm and 50 μm.

By selecting the thickness of the inner thermoplastic composite film to be greater than 35 μm, optical defects due to the embedding of particles between the thermoplastic interlayer and the inner glass sheet can be minimized. The higher thickness absorbs particles 25 μm or less in diameter during the manufacturing of the composite glass sheet, whereby no spot areas appear when laminating the layer stack to form the composite glass sheet. The dotted areas represent optical defects in the composite glass sheet that occur as visible dots that are distinguishable from the rest of the composite glass sheet. The complete absorption of the one or more particles by the thermoplastic interlayer results in an improved optical quality of the composite glass sheet.

Clean rooms are used when very clean ambient air is advantageous. This may be the case in the medical, production or research fields. Clean rooms are closed chambers in which temperature, humidity and air pressure can be precisely controlled. Furthermore, contamination due to airborne and surface particles can be reduced. The causes of such contamination include, inter alia, the human user and the instruments and processes used. The grading of individual cleanrooms is performed according to the number and size of particles per cubic meter of air. Cleanrooms are classified according to the classification system of EN ISO 14644 (EN-european standard, ISO-international organization for standardization) into different classes from 1 to 9 according to the contamination situation. For example, an ISO class 8 clean room allows, for example, 3520000 particles of 0.5 μm diameter, 832000 particles of 1.0 μm diameter, and 29300 particles of 5.0 μm diameter per cubic meter of air. In order to also approximate the number of larger particles, the following formula has proved useful:

parameter(s)C _n Denotes the maximum permissible concentration of particles per cubic meter of air, greater than or equal to the particle size under consideration, rounded to the nearest whole number. Parameter(s)NIs a classification number of ISO class. N is not allowed to be greater than 9 and values between ISO classes may be shown as the smallest possible increment by 0.1. Parameter(s)DIs the particle size considered in microns.

It has been found that when using an inside thermoplastic composite film having a thickness of < 35 μm, a class ISO 5 clean room is necessary to minimize the occurrence of domains of spot-like areas on the composite glass sheet.

In a preferred embodiment, an inside thermoplastic composite film having a thickness of 35 to 250 μm is used in manufacturing composite glass panels in an ISO class 8 clean room. It has been shown that for statistical observations about 1000 particles with a diameter < 25 μm and 2 particles with a diameter < 500 μm are present per cubic meter of air in a clean room class ISO 8. It also shows that for statistical observations only 1 particle with a diameter of < 25 μm is present per cubic meter of air in a class ISO 5 cleanroom. By using an inside thermoplastic composite film having a thickness of 35 to 250 μm, the manufacture of the composite glass sheet may be performed in a class ISO 8 clean room, wherein particularly good results are obtained.

In a preferred method variant, the composite glass sheet is manufactured using a

class ISO

5, 6, 7 or 8 cleanroom, preferably a class ISO 8 cleanroom. The use of clean rooms with larger ISO grades in the manufacture of composite glass sheets represents an economic advantage because of the lower requirements placed on ambient air cleanliness. The manner of handling can also be facilitated, since human users need to be more careful when using clean rooms with smaller ISO grades.

In a preferred embodiment of the invention, the functional layer has properties such as infrared absorption, infrared reflection, polarized light reflection, aesthetic and/or specific coloration, electrical conductivity or combinations thereof. These properties are very advantageous for various applications with optical requirements. The functional layer may also have an anti-fog coating (also known as anti-fog). In the context of the present invention, antifog coating refers to a special surface treatment of the transparent surface which prevents fogging, i.e. condensation, under the action of water vapor. Preferably, the anti-fog coating comprises a wetting agent that reduces the surface tension of water and/or the interfacial tension of water with the coated surface. Preferably, the wetting agent is a surfactant. Alternatively, the anti-fog coating comprises a polymer film in which nanoparticles are embedded. Preferably, the anti-fog coating consists of a polymer film in which nanoparticles are embedded. The nanoparticles are preferably composed of at least 95% silicon oxide.

In another preferred embodiment, the functional layer is an emissivity reducing layer. The emissivity reducing layer is referred to as a thermal radiation reflecting layer. Such layers are also commonly referred to as low-e layers or low-e layers. It has the function of preventing heat from radiating into the inner space (heat radiation from the glass sheet itself) and also from radiating out from the inner space. In the context of the present invention, emissivity is understood to mean the standard emissivity of heat radiation according to standard EN 12898 at 283K. Emissivity reducing layers are known to those skilled in the art. They can be designed, for example, as disclosed in WO2018206236 A1.

In a preferred embodiment of the invention, the functional layer consists of a seamless flat layer based on a PET- (polyethylene terephthalate) polymer layer, having reflective and/or absorptive properties and/or having a specific and/or aesthetic coloration and/or electrical conductivity. The electrical conductivity of the functional layer can preferably be achieved by a metallic, preferably silver and/or copper, coating on the functional layer. This results in improved suitability, for example, in HUD systems.

The area that can be used as a projection surface for the virtual image is called a HUD system. For this purpose, sensors are mounted behind the composite glass pane. The optical module illuminates an image onto the sensor, in the light path of which a composite glass plate is present. The image may be reflected by a reflective functional layer used in the composite glass sheet. A user, such as a driver of a passenger vehicle, may visually perceive the reflected image. Important information can be transmitted to the driver via the image, for example the speed of the vehicle used or a navigation message.

In a particularly preferred embodiment of the invention, the functional layer is a reflective film having reflective properties with respect to p-polarized radiation. The reflective film may be a carrier film with a reflective coating or a reflective polymer film. The reflective coating preferably comprises at least one metal-based layer or a pure dielectric layer sequence with alternating refractive indices. The metal-based layer preferably comprises or consists of silver and/or aluminium. The dielectric layer sequence preferably comprises silicon nitride, silicon oxide and/or zinc oxide. The reflective polymer film preferably comprises or consists of a dielectric polymer layer. The dielectric polymer layer preferably comprises PET. A functional layer of this composition is suitable for reflecting p-polarized light in the visible spectral range impinging on the layer. The functional layer preferably reflects at least 5%, particularly preferably at least 10%, in particular 20%, of the p-polarized light. In this embodiment, the composite glass sheet is preferably used as a windshield in a vehicle having a p-polarized HUD. The composite glass sheet is part of a projection device in which the functional layer is illuminated by a projector. The p-polarized radiation image produced by the projector is reflected on the functional layer. The radiation of the projector preferably strikes the composite glass pane at an angle of incidence of 45 ° to 75 °, in particular 60 ° to 70 °. The image reflected at the functional layer can be perceived as a virtual image by the passenger, in particular the driver. The use of the composite glass pane according to the invention in HUD systems is particularly suitable due to the thinner thickness of the thermoplastic composite film on the side of the interior space compared to the thermoplastic composite film used according to the standard. The thickness of the thermoplastic composite film as used in the thermoplastic composite film used according to the standard may impair the optical quality of the composite glass sheet.

The angle of incidence is the angle between the vector of incidence of the projector radiation and the surface normal in the geometric center of the HUD region. Since the angle of incidence of about 65 ° typical for HUD projection devices is relatively close to the brewster angle of the air-glass-transition (57.2 °, soda-lime glass), the p-polarized radiation proportion of the radiation emitted by the projector is hardly reflected by the glass-plate surface.

The functional layer preferably comprises or consists of a functional element having electrically switchable or electrically adjustable optical properties. For example, the functional element may be a polymer dispersed liquid crystal film (PDLC), an Organic Light Emitting Diode (OLED), or a Liquid Crystal Display (LCD).

In the PDLC functional layer, the active layer contains liquid crystals embedded in a polymer matrix. If no voltage is applied to the planar electrodes of the PDLC functional layer, the liquid crystals orient in a disordered manner, which results in strong scattering of light through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals are aligned toward a common direction, and the transmittance of light passing through the active layer increases. In principle, it is also possible for the liquid crystal to have an ordered state when no voltage is applied to the planar electrodes of the PDLC functional layer and for the liquid crystal to be in a disordered state when a voltage is applied to the planar electrodes of the PDLC functional layer.

In the case of organic light-emitting diodes (OLEDs), the functional layer contains an electroluminescent material, in particular an organic electroluminescent material, the emission of which is excited by applying a voltage. The electroluminescent functional layer can be produced as a simple light source or as a display with arbitrary display. Such a display may be used, for example, in a windshield to insert information for the driver. For example, the current speed or other status parameters may be displayed. Instead, images from a rearward-directed camera are displayed instead of the rear view mirror. Of course, in the case of a display, simple planar electrodes each having the same potential overall are not sufficient — instead, the individual pixels have to be controlled individually. The measures required for this are known per se to the person skilled in the art and OLED display films are commercially available.

In the case of a Liquid Crystal Display (LCD), the functional layer comprises a liquid crystal active layer that affects the polarization direction of light passing through the functional layer upon application of a particular voltage.

The functional layer preferably has a thickness of 20 μm to 120 μm, particularly preferably of 30 μm to 90 μm, very particularly preferably of 55 μm to 75 μm. These thicknesses of the functional layer have proven to be particularly advantageous.

In a preferred embodiment, the first protective layer and the second protective layer comprise, independently of each other, at least polypropylene (PP) or Polyethylene (PE), copolymers or block polymers thereof. The protective layer serves in particular to protect the functional layer from dirt or scratches. In laminating to form a composite glass sheet, the protective layer must be removed prior to lamination.

In another preferred embodiment, the first and second protective layers comprise at least PP or PE or derivatives thereof independently of each other. In addition, the thermoplastic composite film on the inner space side contains PVB having a thickness of 35 to 50 [ mu ] m. It has been found that electrostatic charging can occur, in particular when removing protective layers comprising PP or comprising PE from thermoplastic PVB composite films, which can lead to attraction of environmental particles. The method according to the invention is particularly effective when the first protective layer and/or the second protective layer comprises or consists of PP or PE.

In a preferred embodiment, the outer glass pane and/or the inner glass pane can comprise or consist of quartz glass, borosilicate glass, soda-lime glass or polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester or polyvinyl chloride. The inner and outer glass plates are preferably made of soda lime glass. The inner and outer glass sheets may be clear or tinted independently of each other.

The outer glass plate and the inner glass plate may be flat glasses (plate glasses). This is particularly suitable for use in the building field. Alternatively, the outer and inner glass plates may also be curved. This is particularly suitable for use in the field of vehicles.

The inner and outer glass sheets may have the same thickness or different thicknesses. Preferably, glass sheets having a thickness of 0.8 mm to 5.0 mm, preferably 1.4 mm to 2.5 mm are used. For example, a standard thickness of 1.6 mm or 2.1 mm is used. However, it is also possible that the outer glass pane and/or the inner glass pane have a thickness of 0.55 mm or 0.7 mm.

The inner and/or outer glass plates may have other suitable coatings known per se, such as a release coating, a tint coating, an anti-reflective coating, a scratch-resistant coating, or a low-e coating (i.e. emissivity reducing coating). An example of coated glass is low emissivity glass (low emissivity glass).

In a preferred embodiment, the inner thermoplastic composite film has a wedge angle (α) of 0.2 mrad to 1 mrad. The thickness of the inner thermoplastic composite film continuously increases from one edge to the other. For example in a vertical run from the lower edge to the upper edge of the windscreen panel. The resulting wedge angle improvement uses composite glass plates for HUD systems. The use of wedge angles in the inner thermoplastic composite film improves image quality in HUD systems.

The invention also relates to a composite glass pane produced or producible by the method according to the invention.

The invention relates to a composite glass panel according to the invention, comprising an outer thermoplastic composite film having a thickness of 300 to 1000 [ mu ] m, preferably 380 to 900 [ mu ] m, particularly preferably 510 to 840 [ mu ] m, a functional layer having a thickness of 55 to 75 [ mu ] m, preferably 55 to 60 [ mu ] m, and an inner thermoplastic composite film having a thickness of 35 to 250 [ mu ] m, preferably 35 to 150 [ mu ] m, particularly preferably 35 to 50 [ mu ] m.

The invention relates to the use of the composite glass pane according to the invention in land, water and air vehicles, in particular in motor vehicles, for example as a windshield pane, rear pane, side pane and/or roof pane, preferably as a windshield pane or as a functional and/or decorative individual part, and as a component in furniture, appliances and buildings.

Embodiments of the invention are illustrated in the drawings and described in more detail below. The figure is simplified and not true to scale.

Shows that:

figure 1 vertical longitudinal section through an edge region of a composite glass sheet according to the prior art before lamination (a) and after lamination (B),

figure 2 vertical longitudinal sections through the edge region of a composite glass sheet according to the invention before lamination (a) and after lamination (B),

fig. 3 shows the method steps for producing a composite glass pane according to the invention in an intermediate stage.

The invention is explained below in terms of construction and optionally also in terms of modes of operation of the invention as shown with reference to the accompanying drawings.

Fig. 1 shows a partial vertical longitudinal section through a composite glass pane 1 according to the prior art before (a) and after (B) lamination.

The composite glass pane 1 comprises, in the order shown in figure a, an outer glass pane 2 having an outer side surface I and an interior space side surface II, an outer thermoplastic composite film 4, a functional layer 6 having a first surface V and a second surface VI, an inner thermoplastic composite film 5 and an inner glass pane 3 having an outer side surface III and an interior space side surface IV. The stack of layers in figure a is laminated to form the composite glass sheet 1 in figure B.

The first particles 8 are located between the outer glass pane 2 and the outer thermoplastic composite film 4 and the second particles 9 are located between the inner glass pane 3 and the inner thermoplastic composite film 5. The

particles

8 and 9 come from pollution of the ambient air. In fig. B, the second particles 9 produce punctiform regions 10 in the laminated composite glass pane 1. The dotted area 10 is an optical defect in the form of a visible dot after completion of the composite glass sheet 1. The particles 8 do not cause visible spots in the laminated composite glass sheet because the outer thermoplastic composite film 4 is thicker and less sensitive to particles than the thinner inner thermoplastic composite film 5.

The composite glass pane 1 can be used, for example, as a windshield pane. The outer glass plate 2 and the inner glass plate 3 are made of soda lime glass, for example. The outer glass plate 2 has, for example, a thickness of 2.1 mm; the inner glass sheet 3 has, for example, a thickness of 1.6 mm. The outer thermoplastic composite film 4 is, for example, a PVB film of 0.81 mm thickness, which preferably has acoustic damping properties. The inner thermoplastic composite film 5 is composed of, for example, a PVB film having a thickness of 20 μm. The functional layer 6 is, for example, a polymer layer based on polyethylene terephthalate (PET) which has various functions such as infrared absorption, infrared reflection, reflection of polarized light, antifog coating, aesthetic and/or specific coloration, electrical conductivity or a combination of these functions. For example, the functional layer 6 has a thickness of 75 μm. The

particles

8, 9 are ambient particles from the air present in a clean room of ISO 8 class. In a grade ISO 8 clean room according to the EN ISO 14644 classification system, 29300 particles of diameter ≧ 5.0 μm are present. For example, the diameter of the

particles

8, 9 is 25 μm.

The outer thermoplastic composite film 4 with the functional layer 6 and the inner thermoplastic composite film 5 may be summarized under the term thermoplastic intermediate layer 7. The thickness of the inner thermoplastic composite film 5, for example, 25 μm, is an order of magnitude thinner than the thickness of the outer thermoplastic composite film 4, which is 810 μm. This may result in punctiform regions 10 due to the particles 9 during later lamination.

Fig. 2 shows a partial vertical longitudinal section through a composite glass sheet 1 according to the invention before lamination (a) and after lamination (B). Fig. 2 shows substantially the same features as shown in fig. 1, except that the inner thermoplastic composite film 5 is here thicker according to the invention, preferably having a thickness of 50 μm. The second particles 9 are completely absorbed by the inner thermoplastic composite film 5 due to the increased thickness of the inner thermoplastic composite film 5. The punctiform regions 10 do not appear as optical defects after the completion of the composite glass pane 1 due to the absorption of the second particles 9. Fig. 2 also shows a composite glass sheet 1 produced by the method according to the invention according to fig. 3. The optical properties of the composite glass pane 1 according to the invention can thus be improved compared to the prior art.

Fig. 3 shows the method steps of the method according to the invention for producing a composite glass pane 1, wherein the initial and the respective intermediate stages are illustrated by vertical longitudinal sections through the edge region.

In the first and second method steps (a) and (b), a transition from the provided initial phase (a) to a first intermediate phase (b) is shown. The arrangement of the individual components of the initial stage (a) starts with a protective layer 11 which is applied to the surface V of the functional layer 6. On the second surface VI of the functional layer 6 an inner thermoplastic composite film 5 is applied, which in turn is covered by a protective layer 12. In method step (b), the protective layer 11 is removed, whereby the first surface V of the functional layer 6 is exposed. Analysis shows that only the second surface VI of the functional layer 6, which is covered by the inner thermoplastic composite film 5, is prone to optical defects caused by particle contamination. The reason for the optical defect is because the thickness of the inner thermoplastic composite film 5 is thinner than that of the outer thermoplastic composite film 4. Therefore, the protective layer 12 is not removed in this step.

The initial stage (a) preferably comprises a functional layer 6 comprising PET and an inner thermoplastic composite film 5 and a first protective layer 11 and a second protective layer 12. The functional layer 6 has a thickness of, for example, 75 μm. The inner thermoplastic composite film 5 is, for example, a PVB film of 50 μm thickness. The first protective layer 11 and the second protective layer 12 are composed of PP or PE compounds, for example.

In a third method step (c), the outer thermoplastic composite film 4 is arranged on the first surface V of the functional layer 6. The outer thermoplastic composite film 4 is, for example, a PVB film having acoustic damping properties with a thickness of 0.81 mm.

In a fourth method step (d), the second protective layer 12 is removed and preferably immediately thereafter the existing intermediate stage is transferred onto the outer glass pane 2 and the inner glass pane 3, wherein the outer glass pane 2 is pressed onto the thermoplastic intermediate layer 7 with the inner space-side surface II and the inner glass pane 3 with the outer space-side surface III. The protective layer 12 is stripped from the inner thermoplastic composite film 5 with the supply of ionized air 13 in order to compensate for the electrostatic load when the second protective layer 12 is removed. Contamination from environmental particles is substantially avoided due to the fact that ionized air 13 is used to remove the second protective layer 12 and the functional layer 6 and the outer and inner thermoplastic

composite films

4, 5 are assembled into the inner and

outer glass plates

3, 2 within 30.0 seconds after removal. The ionized air 13 is generated by corona discharge using a saw-tooth type ionizer, for example, and is preferably supplied by a blower when the protective layer 12 is removed. The outer glass plate 2 and the inner glass plate 3 are made of soda lime glass, for example. The outer glass plate 2 has, for example, a thickness of 2.1 mm; the inner glass sheet 3 has, for example, a thickness of 1.6 mm.

In a fifth method step (e), the resulting layer stack is laminated to form a composite glass sheet 1. Composite glass sheet 1 of fig. 3 shows composite glass sheet 1 according to the invention of fig. 2 according to a fifth method step (e). All process steps (a) to (e) are preferably carried out in a clean room of ISO class 8. For example, an ISO class 8 clean room is a room used for grading according to EN ISO 14644. Clean rooms are closed chambers in which temperature, humidity and air pressure can be controlled. Furthermore, contamination by airborne and surface particles can be reduced. In a clean room of ISO class 8, it is not permissible for more than 29300 particles of diameter ≧ 5.0 μm to be present per cubic meter of air.

A composite glass sheet 1 is manufactured according to the method according to the invention in fig. 3, having an inner thermoplastic composite film 5 thinner than 50 μm. No optical defects are formed when manufacturing according to the method according to the invention in fig. 3.

Examples

The composite glass pane 1 according to the invention according to fig. 2 is produced using the method according to the invention according to fig. 3. In a first method step (a), an initial stage is first provided which consists of the first protective layer 11, the functional layer 6, the inner thermoplastic composite film 5 and the second protective layer 12 in this order. The initial phase is transferred to a first intermediate phase by manually stripping off the first protective layer 11 in method step (b). In a third method step (c), a second intermediate stage is produced by arranging the outer thermoplastic composite film 4 onto the first surface V of the functional layer 6. In a fourth method step (d), the second protective layer 12 is removed from the inner thermoplastic composite film 5, wherein simultaneously ionized air 13 is supplied according to the invention onto the second intermediate stage. Also in the case of supplying the ionized air 13, the outer glass plate 2 is disposed on the outer thermoplastic composite film 4 and the inner glass plate 3 is disposed on the inner thermoplastic composite film 5 to form a stacked body after removing the second protective layer 12. In a fifth method step (e), the layer stack is laminated to form a composite glass sheet 1. The composite glass sheet 1 is then evaluated for the presence of optical defects in the form of dots (dots). The number of optical defects in the form of dots found is not significant and does not prevent the use of the composite glass pane 1. The composite glass sheet 1 is classified as "high quality" due to slight optical defects. The results are summarized in table 1.

Comparative example

The comparative example differs from the example according to the invention in the configuration of the fourth process step (d). Further, comparative examples were conducted in the same manner as in examples. In method step (d), no ionized air 13 is supplied to the second intermediate stage and is likewise arranged without ionized air 13 being supplied to form a layer stack. Otherwise, the method corresponds to the method in fig. 1. The results are summarized in table 1.

TABLE 1

	A significant number of optical defects in the form of dots
		Examples	Whether or not
Comparative example	Is that

In contrast to the composite glass sheet in the comparative example, the composite glass sheet according to the present invention in the examples had little to no optical defects in the form of visible dots. As a cause of the high-quality optical difference between the composite glass plates of the two embodiments, the electrostatic load during and after the stripping of the second protective layer 12 at the second intermediate stage can be mentioned. The electrostatic loading of the second intermediate stage due to stripping results in attracting ambient particles, which are embedded between the inner glass pane 3 and the thermoplastic intermediate layer 7. After lamination in the fifth method step (e), optical defects in the form of visible spots are produced on the composite glass pane as a result of these inserts. In this embodiment, this problem is solved by supplying ionized air 13 according to the invention in a fourth method step (d).

The method according to the invention for producing composite glass panes therefore combines a feasible operating mode with a high optical quality of the produced composite glass panes. This result is unexpected and surprising to those skilled in the art.

List of reference numerals:

1. composite glass plate

2. Outer glass plate

3. Inner glass plate

4. Outside thermoplastic composite film

5. Inner thermoplastic composite film

6. Functional layer

7. Thermoplastic interlayer

8. First particles

9. Second granule

10. Dotted region

11. First protective layer

12. Second protective layer

13. Ionized air

Composite glass pane 1 before A lamination

B laminated composite glass plate 1

I outer surface of the outer glass pane 2

II surface of the outer glass plate 2 on the inner space side

III outer side surface of the inner glass plate 3

IV inner glass plate 3 inner space side surface

First surface of V functional layer 6

Second surface of the VI functional layer 6

(a) First method step

(b) Second method step

(c) Third method step

(d) Fourth method step

(e) A fifth method step.

Claims

1. Method for manufacturing a composite glass pane (1), wherein:

(a) Providing a layer sequence comprising the following sequence

-a first protective layer (11),

-a functional layer (6) arranged on the first protective layer (11),

-arranging an inner thermoplastic composite film (5) on a functional layer (6),

-and a second protective layer (12) arranged on the inner thermoplastic composite film (5),

(b) Removing the first protective layer (11) from the functional layer (6),

(c) Applying an outer thermoplastic composite film (4) to the functional layer (6),

(d) Removing the second protective layer (12) from the inner thermoplastic composite film (5) with supply of ionized air (13) and arranging the outer glass pane (2) on the outer thermoplastic composite film (4) and the inner glass pane (3) on the inner thermoplastic composite film (5) to form a stack, and

(e) Laminating the stack of layers obtained from method step (d) to form a composite glass sheet (1).

2. The method according to claim 1, wherein the outer thermoplastic composite film (4) and the inner thermoplastic composite film (5) independently of each other comprise at least polyvinyl butyral, ethylene vinyl acetate, polyurethane or mixtures or copolymers or block polymers thereof, preferably polyvinyl butyral.

3. The method according to any one of claims 1 or 2, wherein the thickness of the outer thermoplastic composite film (4) is between 300 μm and 1000 μm, preferably between 380 μm and 900 μm, particularly preferably between 510 μm and 840 μm.

4. The method according to any one of claims 1 to 3, wherein the thickness of the inner thermoplastic composite membrane (5) is between 35 μm and 250 μm, preferably between 35 μm and 150 μm, particularly preferably between 35 μm and 50 μm.

5. The method according to any one of claims 1 to 4, wherein the functional layer (6) has infrared absorption, infrared reflection, polarized light reflection, anti-fog coating, aesthetic and/or specific coloration, electrical conductivity, emissivity reducing layer or a combination thereof.

6. The method according to any one of claims 1 to 5, wherein the functional layer (6) comprises a polymer dispersed liquid crystal film, an organic light emitting diode or a liquid crystal display.

7. Method according to any one of claims 1 to 6, wherein the functional layer (6) has a thickness of 55 μm to 75 μm, preferably of 55 μm to 60 μm.

8. The method according to any one of claims 1 to 7, wherein the outer and/or inner thermoplastic composite film (4, 5) comprises less than 1% of a plasticizer, preferably no plasticizer.

9. The method according to any one of claims 1 to 8, wherein the method of manufacturing the composite glass sheet (1) is performed in an ISO class 5, 6, 7 or 8 clean room.

10. The method according to any one of claims 1 to 9, wherein at least the outer glass plate (2) and/or the inner glass plate (3) comprises or consists of quartz glass, borosilicate glass, soda lime glass or polyethylene, polypropylene, polycarbonate, polymethylmethacrylate, polystyrene, polyamide, polyester or polyvinyl chloride.

11. The method of any one of claims 1 to 10, wherein the lamination is performed at a sub-pressure of 0.1 bar to 2 bar.

12. The method according to any one of claims 1 to 11, wherein the first protective layer (11) and the second protective layer (12) independently of each other comprise at least polypropylene or polyethylene or copolymers or block polymers thereof.

13. A composite glass sheet (1) manufactured according to the method of any one of claims 1 to 12.

14. The composite glass panel (1) according to claim 13, wherein the thickness of the outer thermoplastic composite membrane (4) is between 300 μm and 1000 μm, preferably between 380 μm and 900 μm, particularly preferably between 510 μm and 840 μm, the thickness of the functional layer (6) is between 55 μm and 75 μm, preferably between 55 μm and 60 μm, and the thickness of the inner thermoplastic composite membrane (5) is between 35 μm and 250 μm, preferably between 35 μm and 150 μm, particularly preferably between 35 μm and 50 μm.

15. Use of a composite glass pane (1) according to claim 13 or 14 in an aeroamphibious vehicle, in particular in a motor vehicle, for example as a windscreen pane, rear glass pane, side glass pane and/or glass roof, preferably as a windscreen pane or as a functional and/or decorative single piece, and as a component in furniture, appliances and buildings.