Composite glass plate and method for manufacturing composite glass plate

Abstract

The present invention relates to a method for manufacturing a composite glass plate (1), wherein: (a) a layer sequence is provided, comprising the following order: - a first protective layer (11), - a functional layer (6) disposed on the first protective layer (11), - an inner thermoplastic composite film (5) disposed on the functional layer (6), - and a second protective layer (12) disposed on the inner thermoplastic composite film (5), (b) the first protective layer (11) is removed from the functional layer (6), (c) an outer thermoplastic composite film (4) is applied to the functional layer (6), (d) the second protective layer (12) is removed from the inner thermoplastic composite film (5) while ionized air (13) is supplied, and an outer glass plate (2) is disposed on the outer thermoplastic composite film (4) and an inner glass plate (3) is disposed on the inner thermoplastic composite film (5) to form a stacked body, and (e) the stacked body obtained by method step (d) is laminated to form a composite glass plate (1).

Description

[0001] This invention relates to a method for manufacturing composite glass panels. This invention also relates to composite glass panels and their uses.

[0002] Head-up displays (HUDs) are currently widely used in vehicles and aircraft. The working principle of a HUD involves using an imaging unit that projects an image using optical modules and a projection surface. This image is perceived as a virtual image by the driver. If this image is reflected, for example, by a windshield panel serving as the projection surface, it can display important information to the user, significantly improving traffic safety.

[0003] A windshield panel consists of two glass panes bonded together by a thermoplastic layer. If the windshield panel is required to have special functions, such as absorbing infrared light, reflecting polarized or infrared light, being conductive, or for aesthetic purposes, it is advantageous to use a functional interlayer or functional element. Composite glass using multiple layers is known from WO 2018 / 010865 A1, WO 2018 / 082920 A1, and WO2020 / 094422A1.

[0004] The thermoplastic layer used can be composed of polyvinyl butyral (PVB) and applied to the functional interlayer in varying thicknesses. To avoid compromising the optical quality of the composite glass, the thermoplastic layer used must be thinner than the thermoplastic layer in the composite glass used according to the standard. The composite glass used according to the standard has a thermoplastic layer thickness of 0.38 mm or 0.76 mm.

[0005] WO 2020 / 017502 A1 discloses a composite glass panel with an intermediate layer between an outer glass panel and an inner glass panel, bonded by a thermoplastic layer, preferably PVB. Since an excessively thick thermoplastic layer at the intermediate layer interferes with the HUD image, the adhesive layer needs to be applied as thinly as possible. However, if the adhesive layer is applied too thinly, it may result in insufficient venting, leading to a deterioration in the quality of the composite glass. To address this issue, an adhesive layer with a suitable thickness of 0.2 μm to 70 μm is disclosed, which both reduces interference with the HUD image and improves venting during the manufacturing process of the laminated composite glass panel.

[0006] The object of this invention is to provide laminated composite glass sheets with high optical quality. A further object of this invention is to provide a method for manufacturing such sheets and their uses.

[0007] According to the present invention, the object of the invention is achieved by a method for manufacturing a composite glass plate according to the present invention. Preferred embodiments will be derived from further description.

[0008] This invention relates to a method for manufacturing a composite glass plate. The method is divided into several steps. In a first step, a layer sequence is provided. This layer sequence includes, in the following order: 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 step, the first protective layer is removed from the functional layer. In a third step, an outer thermoplastic composite film is applied to the functional layer. In a fourth step, the second protective layer is removed from the inner thermoplastic composite film, wherein the removal of the second protective layer is performed with ionized air supplied. After the removal of the second protective layer, an outer glass plate is disposed on the outer thermoplastic composite film and an inner glass plate is disposed on the inner thermoplastic composite film to form a laminate. In a fifth step, the laminate obtained in the fourth step is laminated to form a composite glass plate.

[0009] The layer sequence provided in the first method step preferably consists of layers that are firmly bonded to each other; in particular, the functional layer and the inner thermoplastic composite film have been pre-laminated. The first and second protective layers are bonded to the other layers of the layer sequence by an adhesive layer, preferably an adhesive. Alternatively, the provided layer sequence may also be loosely bonded to each other, so that the individual layers can be loosely stacked on top of each other.

[0010] In the fourth step, the second protective layer can be peeled off from the inner thermoplastic composite film by mechanical or manual operation with the supply of ionized air. The second protective layer is preferably peeled off in a time frame of less than 60.0 seconds, more preferably less than 5.0 seconds, and particularly less than 3.0 seconds. After peeling off the second protective layer, a laminate is formed by arranging the outer glass plate on the outer thermoplastic composite film and the inner glass plate on the inner thermoplastic composite film. The arrangement of the laminate is preferably carried out within less than 10 minutes, particularly preferably less than 5 minutes, and especially less than 1 minute.

[0011] In another preferred embodiment, the ionized air is generated in the fourth method step by a comb-type or sawtooth-type ionizer. The comb-type or sawtooth-type ionizer generates oxygen ions by means of high voltage. For example, these ions can be generated by ionizing radiation or so-called corona discharge.

[0012] In another preferred embodiment, the ionized air is generated by a comb-type or sawtooth-type ionizer in the fourth method step. The air ionized in this manner is supplied in the fourth method step via a blowing device. This blowing device preferably comprises a blower.

[0013] The composite glass panel is preferably used as a window glass panel, suitable for and configured to separate an interior space from the external environment. In the context of this invention, the inner glass panel refers to the glass panel of the composite glass panel facing the interior space (especially the interior space of a vehicle). The outer glass panel refers to the glass panel facing the external environment.

[0014] The outer glass panel and the inner glass panel each have an outer surface and an inner space side surface, and a surrounding side edge extending therebetween. In the context of this invention, the outer surface refers to the main surface provided for facing the external environment in the installation position. In the context of this invention, the inner space side surface refers to the main surface provided for facing the inner space in the installation position. The inner space side surface of the outer glass panel and the outer surface of the inner glass panel face each other and are bonded together in the composite glass panel by a thermoplastic interlayer. The outer thermoplastic composite film, the functional layer, and the inner thermoplastic composite film are arranged in this order and are referred to as the thermoplastic interlayer in the upper and lower parts of this invention.

[0015] The functional layer has an outer first surface and an inner space-side second surface, and a surrounding side edge extending therebetween. In the context of this invention, the first surface of the functional layer refers to the surface configured to face the external environment in the installation position. In the context of this invention, the second surface of the functional layer refers to the surface configured to face the inner space in the installation position. The first surface of the functional layer is bonded to the outer thermoplastic composite film, and the second surface of the functional layer is bonded to the inner thermoplastic composite film.

[0016] Composite glass panels are described as having the inner space side surface of an outer glass panel and the outer side surface of an inner glass panel facing each other and bonded together by a thermoplastic interlayer.

[0017] It has been shown that, without the use of ionized air, the attraction of environmental particles due to the removal of the protective layer can lead to contamination of the laminated stack. The use of ionized air in the fourth method step prevents electrostatic loading of the layer sequence, thereby reducing the attraction of environmental particles to the inner thermoplastic composite membrane. By using ionized air while removing the second protective layer, users can eliminate the need for a cleanroom with a lower ISO class, which translates to an economic advantage.

[0018] The composite glass sheet according to the invention is manufactured by lamination. Lamination can be performed by methods known per se. An outer glass sheet, an inner glass sheet, and a thermoplastic interlayer therebetween are laminated together, for example by autoclave method, vacuum bag method, vacuum ring method, calendering method, vacuum laminator, or a combination thereof. The bonding of the outer and inner glass sheets is generally carried out under the action of heat, vacuum, and / or pressure.

[0019] In a preferred embodiment, lamination is performed under a negative pressure of 0.1 bar to 2 bar, preferably 0.5 bar to 1 bar. Very good results are obtained within this pressure range.

[0020] In another preferred embodiment, lamination is carried out by autoclave method at an overpressure of 800 to 15 bar, preferably 10 to 13 bar, and particularly about 12 bar. This pressure range has proven particularly useful in autoclave method.

[0021] In another particularly preferred embodiment, lamination is carried out at a temperature of 120°C to 150°C. This temperature is very suitable for lamination because it is above the glass transition temperature for many thermoplastic materials.

[0022] In a preferred embodiment, the outer and inner thermoplastic composite films independently comprise at least PVB, ethylene vinyl acetate (EVA), polyurethane (PU), or mixtures, copolymers, or block polymers thereof, preferably PVB. These materials have proven useful for use as thermoplastic interlayers in composite glass sheets and for establishing adhesive bonding with the glass. This ensures good bonding between the outer and inner glass sheets and the thermoplastic functional layers.

[0023] In a preferred embodiment, the outer thermoplastic composite film and / or the inner thermoplastic composite film contain no or substantially no plasticizer. In the context of this invention, "substantially no plasticizer" means that the outer thermoplastic composite film and / or the inner thermoplastic composite film contain less than 1% plasticizer. This has the advantage of allowing for the manufacture of stiffer thermoplastic composite films, particularly thinner extrusions. In a preferred embodiment, the thermoplastic composite film thus contains as little plasticizer as possible to enable it to be manufactured as thin as possible.

[0024] In a preferred embodiment, the thickness of the outer thermoplastic composite film is from 20 μm to 2000 μm, preferably from 300 μm to 1000 μm, particularly preferably from 380 μm to 900 μm, and especially from 510 μm to 840 μm. The intermediate layer within this range is advantageous for bonding and weight reduction.

[0025] The outer thermoplastic composite film can be a functional composite film. "Functional composite film" herein refers to an outer thermoplastic composite film having at least one special function, particularly sound damping, coloring, solar energy function, or a combination of these functions. In the context of this invention, "thermoplastic composite film with solar energy function" means that the thermoplastic composite film absorbs or reflects infrared radiation and / or UV radiation. In the context of this invention, a functional composite film with solar energy function means that solar radiation is absorbed by the functional composite film. In the context of this invention, a functional composite film with coloring function means that the functional composite film is colored.

[0026] Acoustic damping composite membranes are typically characterized by so-called mechanical impedance measurement (MIM). This is a standardized method according to ISO 16940, where damping can be calculated by measuring the natural frequency. According to current standards, the acoustic damping composite membrane to be examined is laminated between two glass plates with a thickness of 2.1 mm to allow for comparisons with different glass thicknesses. This enables those skilled in the art to select a suitable interlayer using well-known standardized measurement methods.

[0027] Mechanical impedance measurements were performed as early as one month after the manufacture of the composite glass plate. Furthermore, the acoustic damping composite membrane itself was laminated with two 2.1 mm thick glass plates to form the composite glass plate as early as one month after its manufacture. This ensured that a stable state was achieved at the time of measurement.

[0028] It has proven particularly advantageous that the outer thermoplastic composite film, which bonds the functional layer to the outer glass panel, is designed as an acoustic damping composite film. This results in favorable acoustic damping properties for the composite glass panel.

[0029] In another preferred embodiment of the invention, the thickness of the inner thermoplastic composite film is 35 μm to 250 μm, preferably 35 μm to 150 μm, particularly preferably 35 μm to 100 μm, and especially 35 μm to 50 μm.

[0030] By selecting a thickness greater than 35 μm for the inner thermoplastic composite film, optical defects caused by the embedding of particles between the thermoplastic interlayer and the inner glass plate can be minimized. During the manufacturing process of the composite glass plate, the higher thickness absorbs particles with a diameter of 25 μm or smaller, thus preventing the appearance of dot-like areas when the layers are laminated to form the composite glass plate. Dot-like areas refer to optical defects that appear as visible dots in the composite glass plate, distinguishable from the rest of the composite glass plate. The improved optical quality of the composite glass plate is achieved through the complete absorption of one or more particles by the thermoplastic interlayer.

[0031] Cleanrooms are used when very clean ambient air is favorable. This may be the case in medical fields, manufacturing plants, or research fields. A cleanroom is a closed room where temperature, humidity, and air pressure are precisely controlled. Furthermore, it reduces contamination caused by particles in the air and on surfaces. The causes of this contamination include, in particular, human users, the equipment used, and the processes employed. Cleanrooms are classified according to the number and size of particles per cubic meter of air. According to the EN ISO 14644 (EN - European Standard, ISO - International Organization for Standardization) classification system, cleanrooms are divided into different classes from 1 to 9 based on their contamination levels. For example, an ISO Class 8 cleanroom allows for, for example, 3,520,000 particles ≥0.5 μm in diameter, 832,000 particles ≥1.0 μm in diameter, and 29,300 particles ≥5.0 μm in diameter per cubic meter of air. The following formula has proven useful for approximating the number of larger particles:

[0032]

[0033] Parameter C n This represents the maximum permissible concentration per cubic meter of air of particles larger than or equal to the considered particle size, rounded to the nearest integer. Parameter N is the ISO class designation number. N is not allowed to exceed 9, and values ​​between ISO classes can be indicated by 0.1 as the smallest possible increment. Parameter D is the considered particle size in micrometers.

[0034] It has been found that when using inner thermoplastic composite films with a thickness of <35μm, an ISO Class 5 cleanroom is necessary to minimize the occurrence of dot-like areas on the composite glass plate.

[0035] In a preferred embodiment, an inner thermoplastic composite film with a thickness of 35 μm to 250 μm is used when manufacturing the composite glass panel in an ISO Class 8 cleanroom. It has been shown that, statistically, there are approximately 1000 particles ≤25 μm in diameter and 2 particles ≤500 μm in diameter per cubic meter of air in an ISO Class 8 cleanroom. It has also been shown that, statistically, there is only 1 particle ≤25 μm in diameter per cubic meter of air in an ISO Class 5 cleanroom. By using an inner thermoplastic composite film with a thickness of 35 μm to 250 μm, the manufacturing of the composite glass panel can be carried out in an ISO Class 8 cleanroom, where particularly good results are obtained.

[0036] In a preferred variation of the process, a cleanroom of ISO 5, 6, 7, or 8, preferably ISO 8, is used to manufacture the composite glass panels. Using a cleanroom with a higher ISO class in the manufacture of composite glass panels offers economic advantages because the requirements for ambient air cleanliness are lower. It also simplifies operation, as human users need to exercise greater care when using cleanrooms with lower ISO classes.

[0037] In a preferred embodiment of the invention, the functional layer has properties such as infrared absorption, infrared reflection, polarized light reflection, aesthetics and / or specific coloring, conductivity, or combinations thereof. These properties are highly advantageous for a variety of applications with optical requirements. The functional layer may also have an anti-fog coating (also referred to as anti-fogging). In the context of the invention, an anti-fog coating refers to a special surface treatment of a transparent surface that prevents fogging, i.e., condensation, under the action of water vapor. Preferably, the anti-fog coating contains a wetting agent that reduces the surface tension of water and / or the interfacial tension between water and 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 preferably consist of at least 95% silicon oxide.

[0038] In another preferred embodiment, the functional layer is an emissivity-reducing layer. An emissivity-reducing layer refers to a heat radiation reflective layer. Such a layer is also commonly referred to as a low-emissivity layer or a low-emissivity layer. It has the function of preventing heat radiation into the interior space (from the heat radiation of the glass itself) and preventing heat radiation out of the interior space. In the context of this invention, emissivity is understood to refer to the standard emissivity of thermal radiation at 283K according to standard EN 12898:2019. Emissivity-reducing layers are known to those skilled in the art. They can be designed, for example, as disclosed in WO2018206236A1.

[0039] In a preferred embodiment of the invention, the functional layer comprises a seamless, flat layer based on a PET (polyethylene terephthalate) polymer layer having reflective and / or absorptive properties and / or specific and / or aesthetic coloring and / or conductivity. The conductivity of the functional layer is preferably achieved by having a metallic, preferably silver and / or copper coating on the functional layer. This results in improved applicability, for example, in HUD systems.

[0040] The area that can be used as a projection surface for virtual images is called a HUD system. For this purpose, sensors are mounted behind a composite glass panel. An optical module projects an image onto the sensor, with the composite glass panel present in its optical path. The image can be reflected by a reflective functional layer used in the composite glass panel. Users, such as drivers of passenger vehicles, can visually perceive the reflected image. Important information, such as the speed of the vehicle or navigation messages, can be transmitted to the driver through this image.

[0041] In a particularly preferred embodiment of the invention, the functional layer is a reflective film having reflective properties against p-polarized radiation. The reflective film can 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 sequence of pure dielectric layers with alternating refractive indices. The metal-based layer preferably comprises silver and / or aluminum or is composed of the same. The dielectric layer sequence preferably comprises silicon nitride, silicon oxide, and / or zinc oxide. The reflective polymer film preferably comprises or is composed of a dielectric polymer layer. The dielectric polymer layer preferably comprises PET. This composition of the functional layer is suitable for reflecting p-polarized light in the visible spectrum onto the layer. The functional layer preferably reflects at least 5% of the p-polarized light, particularly preferably at least 10%, and especially 20%. In this embodiment, the composite glass panel is preferably used as a windshield in a vehicle with a p-polarized HUD. The composite glass panel is part of a projection device, wherein the functional layer is illuminated by a projector. The p-polarized radiation image generated by the projector is reflected onto the functional layer. The projector's radiation is preferably incident on the composite glass panel at an angle of 45° to 75°, particularly 60° to 70°. The image reflected on the functional layer can be perceived as a virtual image by passengers, especially the driver. The composite glass panel according to the invention is particularly suitable for use in HUD systems because it is thinner on the interior space side compared to the thermoplastic composite film used according to standards. The thickness of the thermoplastic composite film used, as in the standard-compliant thermoplastic composite film, can compromise the optical quality of the composite glass panel.

[0042] The angle of incidence is the angle between the incident vector of the projector radiation and the surface normal at the geometric center of the HUD area. Since the typical angle of incidence of about 65° for HUD projection devices is relatively close to the Brewster angle (57.2°, soda-lime glass) of the air-glass transition, the p-polarized radiation proportion of the radiation emitted by the projector is hardly reflected by the glass surface.

[0043] The functional layer preferably includes or is composed of functional elements with electrically switchable or electrically adjustable optical properties. For example, the functional elements may be polymer-dispersed liquid crystal films (PDLCs), organic light-emitting diodes (OLEDs), or liquid crystal displays (LCDs).

[0044] In a 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 are oriented randomly, resulting in strong scattering of light passing through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals align in a common direction, and the transmittance of light passing through the active layer increases. It is also theoretically possible that the liquid crystals are in an ordered state when no voltage is applied to the planar electrodes of the PDLC functional layer, and in a disordered state when a voltage is applied to the planar electrodes.

[0045] In the case of organic light-emitting diodes (OLEDs), the functional layer comprises electroluminescent materials, particularly organic electroluminescent materials, whose light emission is excited by the application of a voltage. The electroluminescent functional layer can be used as a simple light source or produced as a display with arbitrary display features. Such a display can be used, for example, in a windshield panel to insert information for the driver. For example, it can display the current speed or other status parameters. Alternatively, it can display an image from a rear-facing camera instead of a rearview mirror. Of course, in the case of a display, simple planar electrodes, each generally having the same potential, are insufficient—instead, each pixel must be individually controlled. The measures required for this are known to those skilled in the art, and OLED display films are commercially available.

[0046] In the case of a liquid crystal display (LCD), the functional layer contains a liquid crystal active layer, which affects the polarization direction of light passing through the functional layer when a specific voltage is applied.

[0047] The functional layer preferably has a thickness of 20 μm to 120 μm, particularly preferably 30 μm to 90 μm, and very particularly preferably 55 μm to 75 μm. These thicknesses of the functional layer have proven to be particularly advantageous.

[0048] In a preferred embodiment, the first and second protective layers independently comprise at least polypropylene (PP) or polyethylene (PE), copolymers thereof, or block polymers. This protective layer is particularly used to protect the functional layers from dirt or scratches. This protective layer must be removed before lamination to form the composite glass sheet.

[0049] In another preferred embodiment, the first and second protective layers independently comprise at least PP or PE or derivatives thereof. Furthermore, the thermoplastic composite film on the interior space side contains PVB with a thickness of 35 μm to 50 μm. It has been found that electrostatic loading can occur, particularly when removing the PP- or PE-containing protective layer from the thermoplastic PVB composite film, leading to the attraction of environmental particles. The method according to the invention is particularly effective when the first and / or second protective layers comprise or are composed of PP or PE.

[0050] In a preferred embodiment, the outer and / or inner glass panes may 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 panes are preferably made of soda-lime glass. The inner and outer glass panes may be clear or tinted independently of each other.

[0051] The outer and inner glass panels can be flat glass (flat glass). This is particularly suitable for use in the building sector. Alternatively, the outer and inner glass panels can also be curved. This is particularly suitable for use in the transportation sector.

[0052] The inner and outer glass panels can have the same thickness or different thicknesses. Preferably, a glass panel with a thickness of 0.8 mm to 5.0 mm, more preferably 1.4 mm to 2.5 mm, is used. For example, a standard thickness of 1.6 mm or 2.1 mm is used. However, it is also possible that the outer and / or inner glass panels have a thickness of 0.55 mm or 0.7 mm.

[0053] The inner and / or outer glass panes may have other suitable coatings known per se, such as anti-stick coatings, tinted coatings, anti-reflective coatings, scratch-resistant coatings, or low-emissivity coatings (i.e., emissivity-reducing coatings). An example of coated glass is low-emissivity glass.

[0054] 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 direction from the lower edge to the upper edge of the windshield. This improved wedge angle allows the composite glass panel to be used in a HUD system. The use of a wedge angle in the inner thermoplastic composite film improves the image quality in the HUD system.

[0055] The present invention also relates to composite glass plates manufactured or manufactured by the method according to the present invention.

[0056] The present invention relates to a composite glass plate according to the present invention, comprising an outer thermoplastic composite film with a thickness of 300 μm to 1000 μm, preferably 380 μm to 900 μm, particularly preferably 510 μm to 840 μm, a functional layer with a thickness of 55 μm to 75 μm, preferably 55 μm to 60 μm, and an inner thermoplastic composite film with a thickness of 35 μm to 250 μm, preferably 35 μm to 150 μm, particularly preferably 35 μm to 50 μm.

[0057] The present invention relates to the use of composite glass panels according to the invention in land, sea and air transportation vehicles, particularly in motor vehicles, for example as windshield panels, rear glass panels, side glass panels and / or glass roofs, preferably as windshield panels or as functional and / or decorative single pieces, as well as as components in furniture, appliances and buildings.

[0058] Embodiments of the present invention are shown in the accompanying drawings and described in more detail below. The drawings are simplified and not to scale.

[0059] It shows:

[0060] Figure 1 Vertical longitudinal sections passing through the edge region of the composite glass sheet according to the prior art before lamination (A) and after lamination (B).

[0061] Figure 2 Vertical longitudinal sections passing through the edge region of the composite glass plate according to the invention before lamination (A) and after lamination (B),

[0062] Figure 3 Method steps for manufacturing the composite glass plate according to the present invention through intermediate stages.

[0063] The invention will now be explained with reference to the accompanying drawings, based on the structure and optional operational modes of the invention as shown.

[0064] Figure 1 Showing partial vertical longitudinal sections through the composite glass plate 1 according to the prior art before lamination (A) and after lamination (B).

[0065] The composite glass plate 1 comprises, in the order shown in Figure A, an outer glass plate 2 having an outer surface I and an inner 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 plate 3 having an outer surface III and an inner space side surface IV. The stacked layers in Figure A are laminated to form the composite glass plate 1 in Figure B.

[0066] The first particle 8 is located between the outer glass plate 2 and the outer thermoplastic composite film 4, and the second particle 9 is located between the inner glass plate 3 and the inner thermoplastic composite film 5. Particles 8 and 9 originate from ambient air pollution. In Figure B, the second particle 9 creates a dotted region 10 in the laminated glass plate 1. The dotted region 10 is an optical defect that appears as a visible dot after the laminated glass plate 1 is completed. Particle 8 does not cause visible dots in the laminated glass plate because the outer thermoplastic composite film 4 is thicker than the thinner inner thermoplastic composite film 5 and is less sensitive to particles.

[0067] The composite glass panel 1 can be used, for example, as a windshield. The outer glass panel 2 and the inner glass panel 3 are, for example, made of soda-lime glass. The outer glass panel 2 has, for example, a thickness of 2.1 mm; the inner glass panel 3 has, for example, a thickness of 1.6 mm. The outer thermoplastic composite film 4 is, for example, a 0.81 mm thick PVB film, which preferably has sound damping properties. The inner thermoplastic composite film 5 is, for example, made of a 20 μm thick PVB film. 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, polarized light reflection, anti-fog coating, aesthetics and / or specific coloring, conductivity, or combinations of these functions. For example, the functional layer 6 has a thickness of 75 μm. Particles 8 and 9 are environmental particles from the air present in an ISO Class 8 cleanroom. In an ISO Class 8 cleanroom according to the EN ISO 14644 classification system, there are 29,300 particles with a diameter ≥ 5.0 μm. For example, particles 8 and 9 have a diameter of 25 μm.

[0068] The outer thermoplastic composite film 4, the functional layer 6, and the inner thermoplastic composite film 5 can be collectively referred to as the thermoplastic interlayer 7. The inner thermoplastic composite film 5, for example, has a thickness of 25 μm, which is an order of magnitude thinner than the outer thermoplastic composite film 4 (8-10 μm). This may result in dotted regions 10 due to particles 9 during subsequent lamination.

[0069] Figure 2 The images show partial vertical longitudinal sections passing through the composite glass plate 1 according to the invention before (A) and after (B) lamination. Figure 2 Shows the Figure 1 The features shown are essentially the same, except that the inner thermoplastic composite film 5 is thicker according to the invention, preferably having a thickness of 50 μm. Due to the increased thickness of the inner thermoplastic composite film 5, the second particle 9 is completely absorbed by the inner thermoplastic composite film 5. Due to the absorption of the second particle 9, the dotted region 10 does not appear as an optical defect after the composite glass plate 1 is completed. Figure 2 It also shows that by according to Figure 3 The composite glass plate 1 manufactured according to the method of the present invention. Compared with the prior art, the optical properties of the composite glass plate 1 according to the present invention can therefore be improved.

[0070] Figure 3 The method steps of manufacturing composite glass plate 1 according to the invention are shown, wherein the initial stage and each intermediate stage are shown by a vertical longitudinal section passing through the edge region.

[0071] In the first and second method steps (a) and (b), a transition from the provided initial stage (a) to the first intermediate stage (b) is shown. The arrangement of the components in the initial stage (a) begins with a protective layer 11 applied to surface V of the functional layer 6. An inner thermoplastic composite film 5, which is again covered by the protective layer 12, is applied to the second surface VI of the functional layer 6. In method step (b), the protective layer 11 is removed, thereby exposing the first surface V of the functional layer 6. Analysis shows that only the second surface VI of the functional layer 6, covered by the inner thermoplastic composite film 5, is prone to optical defects caused by particulate contamination. The optical defects are due to the thinner thickness of the inner thermoplastic composite film 5 compared to the outer thermoplastic composite film 4. Therefore, the protective layer 12 is not removed in this step.

[0072] The initial stage (a) preferably includes a PET-containing functional layer 6, an inner thermoplastic composite film 5, 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 50 μm thick PVB film. For example, the first protective layer 11 and the second protective layer 12 are made of PP or PE compounds.

[0073] In the third method step (c), the outer thermoplastic composite film 4 is disposed on the first surface V of the functional layer 6. The outer thermoplastic composite film 4 is, for example, a 0.81 mm thick PVB film with acoustic damping properties.

[0074] In the fourth method step (d), the second protective layer 12 is removed, and preferably immediately thereafter the existing intermediate stage is transferred to the outer glass plate 2 and the inner glass plate 3, wherein the outer glass plate 2 is pressed onto the thermoplastic intermediate layer 7 with the inner space side surface II and the inner glass plate 3 with the outer space side surface III. The protective layer 12 is peeled off from the inner thermoplastic composite film 5 while ionized air 13 is supplied to compensate for the electrostatic charge during the removal of the second protective layer 12. Since ionized air 13 is used to remove the second protective layer 12 and the functional layer 6, as well as the outer thermoplastic composite film 4 and the inner thermoplastic composite film 5, are assembled into the inner glass plate 3 and the outer glass plate 2 within 30.0 seconds after removal, contamination from environmental particles is substantially avoided. Ionized air 13 is generated, for example, by corona discharge using a sawtooth ionizer, and is preferably supplied by a blower during the removal of the protective layer 12. The outer glass plate 2 and the inner glass plate 3 are, for example, made of soda-lime glass. The outer glass plate 2 has a thickness of, for example, 2.1 mm; the inner glass plate 3 has a thickness of, for example, 1.6 mm.

[0075] In the fifth method step (e), the resulting stacked body is laminated to form a composite glass plate 1. Figure 3 The composite glass plate 1 is shown according to step (e) of the fifth method. Figure 2The composite glass plate 1 according to the present invention. All method steps (a) to (e) are preferably performed in an ISO Class 8 cleanroom. For example, an ISO Class 8 cleanroom is a room classified according to EN ISO 14644. A cleanroom is a closed room in which temperature, humidity and air pressure can be controlled. In addition, it can reduce contamination caused by particles in the air and on surfaces. In an ISO Class 8 cleanroom, the presence of more than 29,300 particles with a diameter ≥ 5.0 μm per cubic meter of air is not permitted.

[0076] Composite glass plate 1 according to Figure 3 The method according to the present invention produces an inner thermoplastic composite film 5 that is thinner than 50 μm. According to... Figure 3 When manufactured according to the method of the present invention, no optical defects are formed. Example

[0077] Use according to Figure 3 Manufactured according to the method of the present invention Figure 2 The composite glass plate 1 according to the invention. In a first method step (a), an initial stage is first provided, consisting of a first protective layer 11, a functional layer 6, an inner thermoplastic composite film 5, and a second protective layer 12 in the following order. The initial stage is transformed into a first intermediate stage by manually peeling off the first protective layer 11 in method step (b). In a third method step (c), a second intermediate stage is manufactured by arranging an 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 ionized air 13 is supplied to the second intermediate stage simultaneously according to the invention. Also with the ionized air 13 supplied, after removing the second protective layer 12, an outer glass plate 2 is arranged onto the outer thermoplastic composite film 4 and an inner glass plate 3 is arranged onto the inner thermoplastic composite film 5 to form a stacked body. In a fifth method step (e), the stacked body is laminated to form the composite glass plate 1. The composite glass plate 1 is then evaluated for whether it has optical defects in the form of dots. The number of point-like optical defects found was not significant and did not impede the use of composite glass plate 1. Due to the minor optical defects, composite glass plate 1 was classified as "high quality". The results are summarized in Table 1.

[0078] Comparative Example

[0079] The comparative example differs from the embodiment according to the present invention in the configuration of the fourth method step (d). Furthermore, the comparative example is performed in the same manner as the embodiment. In method step (d), ionized air 13 is not supplied to the second intermediate stage, and the layer stack is also arranged to form without the supply of ionized air 13. In addition, the method corresponds to... Figure 1The methods described are summarized in Table 1.

[0080] Table 1

[0081] A significant number of point-like optical defects? Example no Comparative Example yes

[0082] In contrast to the composite glass plate in the comparative example, the composite glass plate according to the invention in this embodiment has almost no to no optical defects in the form of visible dots. The reason for the high-quality optical difference between the composite glass plates of the two embodiments can be attributed to the electrostatic charge during and after the removal of the second protective layer 12. The electrostatic charge in the second intermediate stage caused by the removal attracts environmental particles, which become embedded between the inner glass plate 3 and the thermoplastic intermediate layer 7. After lamination in the fifth method step (e), visible optical defects occur in the composite glass plate due to these embeddings. In this embodiment, this problem is solved by supplying ionized air 13 according to the invention in the fourth method step (d).

[0083] Therefore, the method according to the invention for manufacturing composite glass plates combines a feasible operating procedure with the high optical quality of the manufactured composite glass plates. This result is unexpected and surprising to those skilled in the art.

[0084] List of reference numerals in the attached diagram:

[0085] 1. Composite glass panel

[0086] 2. Outer glass panel

[0087] 3. Inner glass plate

[0088] 4. Outer thermoplastic composite film

[0089] 5. Inner thermoplastic composite film

[0090] 6. Functional Layer

[0091] 7. Thermoplastic Interlayer

[0092] 8 First particle

[0093] 9 Second particle

[0094] 10 dotted areas

[0095] 11 First protective layer

[0096] 12 Second protective layer

[0097] 13 Ionized air

[0098] A. Composite glass plate before lamination 1

[0099] B-laminated composite glass panel 1

[0100] I. Outer surface of outer glass plate 2

[0101] II. Surface of the inner space side of the outer glass panel 2

[0102] III. Outer surface of inner glass plate 3

[0103] IV. Surface of the inner space side of the inner glass plate 3

[0104] The first surface of V functional layer 6

[0105] The second surface of functional layer 6 of VI

[0106] (a) First method steps

[0107] (b) Second method steps

[0108] (c) Third method steps

[0109] (d) Fourth method steps

[0110] (e) Fifth method steps.

Claims

1. A method for manufacturing a composite glass plate (1), wherein: (a) Provide a layer sequence, which includes the following order - 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) Remove the first protective layer (11) from the functional layer (6). (c) Apply the outer thermoplastic composite film (4) onto the functional layer (6). (d) With ionized air (13) supplied, the second protective layer (12) is removed from the inner thermoplastic composite film (5), and the outer glass plate (2) is arranged on the outer thermoplastic composite film (4) and the inner glass plate (3) is arranged on the inner thermoplastic composite film (5) to form a laminated body, and (e) The stack of layers obtained by method step (d) is laminated to form a composite glass plate (1). The thickness of the inner thermoplastic composite film (5) is 35 μm to 250 μm.

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

3. The method according to any one of claims 1 or 2, wherein the thickness of the outer thermoplastic composite film (4) is 300 μm to 1000 μm.

4. The method according to any one of claims 1 to 2, wherein the thickness of the inner thermoplastic composite film (5) is 35 μm to 150 μm.

5. The method according to claim 4, wherein the thickness of the inner thermoplastic composite film (5) is 35 μm to 50 μm.

6. The method according to any one of claims 1 to 2, wherein the functional layer (6) has infrared absorption, infrared reflection, polarized light reflection, anti-fog coating, aesthetic coloring, conductivity, emissivity reduction layer or a combination thereof.

7. The method according to any one of claims 1 to 2, wherein the functional layer (6) comprises a polymer-dispersed liquid crystal film, an organic light-emitting diode, or a liquid crystal display.

8. The method according to any one of claims 1 to 2, wherein the thickness of the functional layer (6) is 55 μm to 75 μm.

9. The method according to claim 8, wherein the thickness of the functional layer (6) is 55 μm to 60 μm.

10. The method according to any one of claims 1 to 2, wherein the outer and / or inner thermoplastic composite films (4, 5) contain less than 1% plasticizer.

11. The method according to any one of claims 1 to 2, wherein the method of manufacturing the composite glass panel (1) is carried out in an ISO 5, 6, 7 or 8 cleanroom.

12. The method according to any one of claims 1 to 2, wherein at least the outer glass plate (2) and / or the inner glass plate (3) comprises quartz glass, borosilicate glass, soda-lime glass, or polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, or polyvinyl chloride, or is composed of the like.

13. The method according to any one of claims 1 to 2, wherein the lamination is performed under a negative pressure of 0.1 bar to 2 bar.

14. The method according to any one of claims 1 to 2, wherein the first protective layer (11) and the second protective layer (12) independently comprise at least polypropylene or polyethylene or copolymers or block polymers thereof.

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