Method for preparing laminated window glass

Abstract

This invention relates to a method. Specifically, it relates to a method for preparing laminated window glass and laminated window glass prepared therefrom, and its uses, comprising providing a first glass sheet formed into a desired shape having a first thickness by a first step, and providing a second glass sheet formed into a desired shape having a second thickness by a second step, having an interlayer between the first and second glass sheets, and pressing the first and second glass sheets and the interlayer together at a temperature and pressure sufficient to bond the interlayer material to the glass sheets, wherein the method further comprises, during lamination, applying a mold of substantially the same shape as the first glass sheet to the second glass sheet to bond the interlayer material to the two glass sheets, such that after lamination, the shape of the second glass sheet is substantially the same as the shape of the first glass sheet.

Description

[0001] This application is a divisional application of Chinese patent application 201880008204.6, filed on January 25, 2018, entitled "A Method".

[0002] This invention relates to a method for manufacturing laminated window glass, and to the use of such laminated window glass in vehicles. More specifically, this invention relates to a method for manufacturing lightweight laminated window glass, and to the use of such lightweight laminated window glass in vehicles, particularly as windshields.

[0003] As is well known, laminated window glass for vehicle windshields typically comprises two shaped panes of glass joined by at least one adhesive layer (such as polyvinyl butyral (PVB)). In the art, each pane of glass is conventionally referred to as a “layer.” Typically, the adhesive layer itself is also referred to as a “layer,” i.e., the PVB layer. The pane of glass configured to face the interior of the vehicle in which the laminated window glass is mounted is typically referred to as the “inner layer,” while the pane of glass configured to face the exterior of the vehicle in which the laminated window glass is mounted is typically referred to as the “outer layer.” Both panes of glass are typically composed of soda-lime silicate glass.

[0004] Each pane of glass used in a vehicle's laminated window is typically shaped or bent in one or two mutually perpendicular directions, making the laminated window glass curved. Many methods are known for bending originally flat panes of glass to the desired curvature to form a windshield.

[0005] For example, one known method is to simultaneously bend a pair of originally flat glass sheets, one on top of the other, separated by a suitable "separating powder" such as calcium carbonate. The inner and outer glass sheets are heated in this manner until they are stretchable and bendable, thus forming them simultaneously by a gravity-induced bending method.

[0006] An alternative method for bending glass sheets used in windshields is to heat and bend the inner and outer layers at different times (usually one after the other), thus forming the inner and outer layers individually. For example, one such method for individually bending flat glass sheets involves passing heated flat glass sheets between a pair of complementary forming members and bending each sheet separately. The glass sheets can then be cooled and assembled and laminated together using a suitable adhesive interlayer such as PVB.

[0007] For example, EP 0398759 describes how to heat a first and a second glass sheet that are combined together to form a single laminated window glass sheet in a heating furnace, so that the temperature of the first and second glass sheets at the outlet of the heating furnace is substantially equal.

[0008] WO 2004 / 085324 A1 describes how glass sheets for producing asymmetrical pairs of laminated window glass are preheated in a preheating furnace and then subjected to a bending process in a bending apparatus. Temperature measurement points are set at the outlet of the bending apparatus to ensure that the glass sheets exhibit uniform bending properties, thereby guaranteeing the same restoring force during cooling.

[0009] US 4,260,408 describes how to form a glass sheet by a bending method, wherein the glass is first formed into a curved longitudinal component by gravity-felling onto a shape die, and then bending a solid lower forming die to complete the bending, which includes complex curved transverse components. Specific speed cycles are provided for raising and lowering the lower forming die to minimize the duration of the forming cycle and to minimize the possibility of misalignment of the glass relative to the shape die during the transfer of the glass from the shape die to the lower forming die and its return to the shape die.

[0010] Damaged glass in a window can also be replaced. For example, GB 2221424 describes a method for increasing the penetration resistance through an opening in a window, characterized in that the glass is removed from the opening in the window and replaced with a laminated window made of the removed glass or a window with substantially the same geometry, the laminated window being bonded together by means of at least one thermoplastic interlayer, with a thinner glass sheet that has been chemically tempered and cut to a size substantially equal to that of the original window.

[0011] However, as the requirements for optical quality of laminated window glass, especially in automotive applications, become increasingly stringent, even slight deformations of the glass surface that cause increased optical distortion in transmission have become increasingly unacceptable, especially when laminated window glass is installed in a vehicle as a windshield (when viewed through glass tilted at an angle to the line of sight).

[0012] For example, WO 2015 / 092385 describes a laminated window glass comprising a first window glass material and a second window glass material connected by at least one adhesive interlayer material. The first window glass material comprises a glass sheet having a first composition, and the second window glass material comprises a glass sheet having a second composition different from the first composition. The laminated window glass has a peripheral region extending at the periphery of the laminated window glass and surface compressive stress in the peripheral region. Edge compression also exists, wherein the magnitude of the edge compression is greater than the magnitude of the surface compressive stress in the peripheral region. Although this document teaches how to achieve lightweight windshields, it does not consider the optical parameters required for lightweight windshields.

[0013] WO 2015 / 031594 discloses a sandwich structure having a first glass layer, a second glass layer, and at least one polymer interlayer between the first and second glass layers. In some embodiments, the first glass layer may consist of tempered glass having first and second surfaces, the second surface being adjacent to the interlayer and chemically polished, and the second glass layer may consist of tempered glass having third and fourth surfaces. The fourth surface is opposite to the interlayer and chemically polished, and the third surface is adjacent to the interlayer and has a substantially transparent coating thereon. In another embodiment, the first glass layer is curved, and the second glass layer is substantially planar and cold-formed onto the first glass layer to provide a difference in surface compressive stress on the surface of the second glass layer. However, the optical properties of the sandwich structure described in this document and prepared using standard lamination processes are not suitable for lighter-weight laminated window glass.

[0014] As is well known, in order to obtain good transmission optics, i.e. low optical power, in a sandwich windshield consisting of two glass plates and an intermediate layer, the surfaces of the two glass plates that are far from the intermediate layer (usually referred to as surfaces 1 and 4) should have as close as possible to the same curvature.

[0015] Furthermore, as described in "Glass Processing Days, 2003, pp. 502-504," the mounting angle of a vehicle windshield affects optical performance. For example, the amplification of light power varies with the mounting angle. Therefore, as the mounting angle increases, better optical quality is required because any defects present in the windshield will be magnified to a greater extent. One way to overcome this problem is to improve the optical quality of the glass used to manufacture laminated windshields; however, it is not always possible to produce glass with improved optical quality at an acceptable commercial cost and yield.

[0016] WO 2016030678 describes a solution to this problem and another way to reduce optical distortion in laminated window glass when installed in a vehicle. In this patent application, the laminated window glass has first and second panes of window glass material, each pane formed between a pair of forming members and then laminated together. The position for bending the first pane of window glass material may be intentionally offset from the position for bending the second pane of window glass material. During the lamination step, the first pane of window glass material may be displaced relative to the second pane of window glass material by lateral and / or longitudinal positional displacement. The first and / or second panes of window glass material may have been cut such that, after lamination, at least a portion of their peripheral edges are aligned.

[0017] However, in WO 2016030678, the inventors started from the position of improving the optical distortion of windshields installed in vehicles, in which each glass piece was produced by the same method and therefore had essentially the same shape and curvature.

[0018] In the automotive industry, the demand for laminated window glass is increasing as the total weight of window glass units decreases.

[0019] One way to achieve such lightweight window glass units is to use asymmetrical glass panes. That is, the individual glass panes that make up the windshield differ in one or more characteristics such as thickness, color, or emissivity. For example, WO 2012 / 073030 describes a laminated window glass comprising a first glass layer with a thickness ranging from 1.9 mm to 2.4 mm for providing mechanical strength, a polymer interlayer, and a much thinner second glass layer ranging from 0.8 mm to 1.4 mm, thereby reducing the overall weight of the window glass.

[0020] Glass sheets for lightweight window glass units of varying thicknesses can be produced simultaneously using methods such as gravity bending. Alternatively, different methods can be used to produce each asymmetric glass sheet for a lightweight window glass unit separately, thus taking advantage of the benefits offered by each method. For example, it has been shown to be advantageous to use separate glass bending operations to prepare the outer glass layer for a lightweight window glass unit in order to ensure good shape control and stress level control. However, it is currently not possible to shape the thin glass layers for a lightweight window glass unit to the same quality level using this method. Therefore, as described in WO 2015 / 098385, the preparation of the inner layer of a lightweight window glass unit using both gravity bending and chemical tempering methods has been proposed. Unfortunately, this method often results in laminated windshields that do not always meet the stringent optical requirements of today's modern laminated windshield glass.

[0021] Therefore, there is a need for a method that can produce asymmetrical and lightweight laminated window glass, such as windshields, using an inner glass layer and an outer glass layer, wherein the inner and outer glass layers are prepared using different forming methods or tools, or the glass layers are produced at different times in the method.

[0022] That is, there is a need for a method of using asymmetric glass layers to manufacture laminated window glass units such as vehicle windshields, which reduces optical distortion when the laminated window glass is installed in a vehicle. Specifically, the interior region of the windshield exhibits improved transmission optics.

[0023] According to a first embodiment of a first aspect of the present invention, a method for preparing laminated window glass is provided, comprising the following steps:

[0024] i) A first glass sheet is provided through a first process, the first glass sheet being formed into a desired shape having a first thickness;

[0025] ii) A second glass sheet is provided by a second process, the second glass sheet being formed into a desired shape having a second thickness;

[0026] iii) Provide an intermediate layer located between the first and second glass sheets; and

[0027] iv) Laminate the first and second glass sheets and the intermediate layer together at temperatures and pressures sufficient to bond the interlayer material to the glass sheets;

[0028] The method is characterized by further comprising the following steps:

[0029] v) During lamination, a mold with a shape substantially the same as that of the first glass sheet is applied to the second glass sheet to bond the interlayer material to the two glass sheets, such that after lamination, the shape of the second glass sheet is substantially the same as that of the first glass sheet.

[0030] In an alternative embodiment of the first aspect of the present invention, a method for preparing laminated window glass is provided, comprising the following steps:

[0031] i) A first glass sheet is provided through a first process, the first glass sheet being formed into a desired shape having a first thickness;

[0032] ii) A second glass sheet is provided by a second process, the second glass sheet being formed into a desired shape having a second thickness; and

[0033] iii) Provide an intermediate layer located between the first and second glass sheets;

[0034] Its features are:

[0035] iv) The first and second glass sheets and the intermediate layer are laminated together at a temperature ranging from 90°C to 132°C and a pressure ranging from 8 bar to 16 bar to bond the intermediate layer material to the two glass sheets; wherein, after lamination, the shape of the second glass sheet is substantially the same as that of the first glass sheet.

[0036] According to the present invention, the thickness of the first glass sheet may be different from the thickness of the second glass sheet. Alternatively, the thickness of the first glass sheet may be the same as the thickness of the second glass sheet. However, when laminating glass sheets of different thicknesses, i.e., preferably when the thickness of the first glass sheet is different from the thickness of the second glass sheet, the method of the present invention is preferably applied.

[0037] Regarding this invention, the inventors have discovered that the lamination of the first and second glass sheets preferably occurs at a temperature in the range of 90°C to 132°C and a pressure in the range of 8 bar to 16 bar. Alternatively, the lamination of the first and second glass sheets preferably occurs at a temperature in the range of 95°C to 130°C and a pressure in the range of 8 bar to 16 bar. More preferably, the lamination of the first and second glass sheets occurs at a temperature in the range of 100°C to 130°C. Even more preferably, the lamination of the first and second glass sheets occurs at a temperature in the range of 100°C to 125°C, 100°C to 120°C, or 95°C to 110°C. However, most preferably, the lamination of the first and second glass sheets occurs at a temperature in the range of 100°C to 110°C. All of the above temperature ranges are preferably used in conjunction with a pressure in the range of 8 bar to 16 bar.

[0038] The lamination step iv) can be carried out in a pressure vessel using a vacuum bag and / or ring. This step can then be performed at a temperature within the range of 80°C.

[0039] However, it should be understood that a range of suitable interlayer materials can be used, with polyvinyl butyral being the preferred interlayer material.

[0040] Regarding the first aspect of the invention, it is preferable to bend the first glass sheet into the desired shape. That is, for the method according to the first aspect of the invention, the first step for forming the first glass sheet into the desired shape includes bending. Furthermore, regarding the method according to the first aspect of the invention, the second step for forming the second glass sheet into the desired shape includes gravity-induced bending.

[0041] The thickness of the second glass sheet is preferably in the range of 0.2 mm to 1.4 mm. More preferably, the thickness of the second glass sheet is in the range of 0.5 mm to 1.0 mm or 0.5 mm to 0.95 mm. The thickness of the second glass sheet may also be in the range of 0.5 mm to 1.2 mm.

[0042] The thickness of the first glass sheet is preferably in the range of 1.4 mm to 2.5 mm. More preferably, the thickness of the first glass sheet is in the range of 1.6 mm to 2.3 mm. The thickness of the first glass sheet may also be in the range of 1.6 mm to 2.1 mm.

[0043] According to a first embodiment of the first aspect of the present invention, the method preferably further includes the following steps:

[0044] v) During lamination, a mold is applied to a second glass sheet, wherein the shape of the mold is substantially the same as that of the first glass sheet.

[0045] The mold can be made of glass, ceramic, or metal. However, it is most preferably made of glass. That is, in a preferred embodiment of the method of the present invention, the mold preferably includes a third glass sheet with a shape substantially the same as the first glass sheet.

[0046] Preferably, the third glass sheet is formed into the desired shape by bending before lamination of the first and second glass sheets.

[0047] The thickness of the third glass sheet is preferably in the range of 1.4 mm to 2.5 mm. More preferably, the thickness of the third glass sheet is in the range of 1.6 mm to 2.3 mm. The thickness of the third glass sheet may also be in the range of 1.6 mm to 2.1 mm.

[0048] Furthermore, it is preferable to prepare the first and third glass sheets in separate bending batches. Therefore, the first and third glass sheets have substantially the same thickness.

[0049] The method according to a first embodiment of the first aspect of the present invention preferably further includes the following steps:

[0050] vi) A foil layer is provided between the second glass sheet and the mold, the mold having a shape substantially the same as the first glass sheet.

[0051] That is, the first embodiment of the first aspect of the present invention preferably further includes the following step: vi) providing a foil layer between a second glass sheet and a third glass sheet, the third glass sheet having a shape substantially the same as the first glass sheet.

[0052] The preferred thickness of the foil layer is 0.05 mm to 0.2 mm. Furthermore, the foil layer preferably includes a non-adhesive film. A suitable non-adhesive film ensures easy separation of the foil layer, the second glass sheet, and the third glass sheet after the lamination process. Preferred non-adhesive foil layer film materials include polyester.

[0053] Therefore, still relating to the first aspect of the invention, after lamination is completed, a third glass sheet and a foil layer are removed from the laminated first and second glass sheets. Even more preferably, after lamination, the foil layer and a mold (preferably in the form of a third glass sheet) with a substantially identical shape to the first glass sheet are removed from the laminated first and second glass sheets in a separate step.

[0054] Therefore, according to a first aspect of the invention, it is preferable to provide a laminated window glass, wherein:

[0055] The first glass sheet includes an outer surface and an inner surface; and

[0056] The second glass sheet includes an outer surface of the second glass sheet and an inner surface of the second glass sheet; and wherein...

[0057] The inner surfaces of the first and second glass sheets are located closest to the intermediate layer; and wherein...

[0058] For a given point on the laminated window glass, the difference between the curvature of the first glass pane and the curvature of the second glass pane at that given point on the laminated window glass produced by the method of the first aspect of the invention has a significantly low value, providing an acceptablely low value for the light power in transmission. That is, the driver of a vehicle in which the laminated window glass is installed sees a low level of distortion.

[0059] That is, preferably, the laminated window glass prepared by the method according to the first aspect of the invention exhibits light power in a transmission value that is no more than 130% of the value recorded for laminated window glass prepared by laminating two identical glass sheets.

[0060] In this case, the light power transmitted through the laminated window glass is measured using an apparatus described in accordance with the ECE R43 standard, or using an apparatus prepared by ISRA Vision AG, or in accordance with appropriate VDA recommendations (such as VDA 312 recommendation (March 2015), which relates to “requirements for test equipment for checking visual distortion at a window in transmission”).

[0061] According to a second aspect of the invention, there is provided a laminated window glass suitable for use in a vehicle, which is prepared according to any of the above-described features associated with the first or alternative embodiments of the invention, said features being present individually or in combination.

[0062] Furthermore, according to a second aspect of the invention, a laminated window glass suitable for use in a vehicle is provided, which is prepared according to any of the above-described features associated with a first embodiment of the invention, wherein the window glass has a 37% improvement in light power compared to a laminated window glass prepared by a lamination method in which a mold of substantially the same shape as the first glass sheet is applied to a second glass sheet during the lamination process.

[0063] According to a third aspect of the invention, the use of laminated window glass prepared according to any combination of the features of the first or second aspect of the invention in vehicles is provided.

[0064] According to the first, second, or third aspect of the invention, the laminated window glass can be any glass product used in a vehicle. However, it is preferred that the laminated window glass according to the first, second, or third aspect of the invention is a vehicle windshield or a vehicle rear window.

[0065] Embodiments of the invention will now be described by way of example only with reference to the following examples and accompanying drawings, wherein:

[0066] Figure 1 This is a simplified cross-sectional view of the laminated window glass prepared according to the present invention.

[0067] Figure 2This is a schematic diagram of a first embodiment of a method for preparing a sandwich windshield according to a first aspect of the present invention.

[0068] Figure 3 This is a schematic diagram of an alternative embodiment of the method for preparing a sandwich windshield according to the first aspect of the present invention.

[0069] Figure 4 This is an illustration of an example of curvature measurement recorded for a laminated windshield.

[0070] Figure 5 This is an illustration comparing examples of curvature measurements recorded on the inner and outer panes of a windshield glass prepared according to the present invention.

[0071] Figure 6 It is an image of a typical prior art lightweight sandwich windshield made using inner and outer glass sheets prepared by conventional methods.

[0072] Figure 7 This is an image of a sandwich lightweight windshield prepared according to the method of the present invention.

[0073] Figure 8 This is a summary flowchart of the first and second embodiments of the method for preparing laminated windshield glass according to the present invention.

[0074] Regarding the present invention, the inventors have discovered that in the preparation of laminated window glass, such as vehicle windshields having two curved glass sheets or layers (where one glass sheet is thinner than the second glass sheet and wherein the glass sheets have been formed into curved structures using different techniques), the thinner glass sheet can be successfully shaped into the curvature and shape of the thicker and more rigid glass sheet using improved glass processing techniques that will be further described herein.

[0075] The inventors also discovered that the coordination of the curved shapes of the two glass panes in a sandwich windshield can be achieved using the process described in the method according to the invention. The following is a comparison with... Figure 2 and 3 Related and such Figure 2 and 3 The illustrated examples further describe the method according to the invention.

[0076] Laminated window glass prepared by each of the following methods can preferably be bent in two directions, each bending direction being orthogonal to the other. The radius of curvature in one or both directions can preferably be between 300 mm and 8000 mm.

[0077] like Figure 1As illustrated, in the laminated window glass 10 prepared according to the method of the present invention, a first layer (or glass sheet) 12 having a concave surface 14 and an opposing convex surface 16 is preferably provided. A second layer (or glass sheet) 20 having a convex surface 24 and an opposing concave surface 22 is also provided. The concave surface 14 of the first layer 12 contacts the intermediate layer 25, and the convex surface 24 of the second layer 20 also contacts the intermediate layer 25.

[0078] Using conventional nomenclature, the convex surface 16 of the first layer 12 is referred to as "surface 1" (or S1) of the laminated window glass 10. The concave surface 14 of the first layer 12 is referred to as "surface 2" (or S2) of the laminated window glass 10. The convex surface 24 of the second layer 20 is referred to as "surface 3" (or S3) of the laminated window glass 10, and the concave surface 22 of the second layer 20 is referred to as "surface 4" (or S4) of the laminated window glass 10.

[0079] Regarding the present invention, the laminated window glass 10 can be a vehicle window glass such as a vehicle windshield (front or rear), vehicle sunroof, vehicle side window, or vehicle rear window. The laminated window glass 10 can also be a building window glass.

[0080] Method 1.

[0081] exist Figure 2 The diagram 180 illustrates an embodiment of a first method for preparing laminated window glass, such as a vehicle windshield, according to a first aspect of the present invention.

[0082] In the first step of this method, a first glass sheet 120 is formed into a desired shape, such as that of a windshield. This can be achieved by using flat glass, such as soda-lime silicate glass, and cutting the glass sheet into a shape with the required edge profile. The glass sheet is then heated to a malleable state and typically shaped by, for example, bending.

[0083] In press bending, this method uses a pair of complementary forming dies; an upper forming die and a lower complementary forming die. Press bending typically involves using at least one heated forming die. The press bending method is used to shape a sheet of glass into, for example, the desired shape of a windshield, which has a radius of curvature between 300 mm and 8000 mm in one or more directions.

[0084] Next, in the first method for preparing laminated window glass according to the invention, a second, thinner sheet 160, such as soda-lime silicate glass, is cut into a shape having the desired edge profile. The second glass sheet is also shaped using, for example, gravity or drooping bending methods to achieve a bending shape equal to or smaller than that of the desired windshield glass. That is, the desired shape of the second glass sheet is achieved by a forming method different from that used for forming the first glass sheet for the windshield glass.

[0085] In the gravity-induced sag bending method, a properly sized flat glass sheet or layer is placed on top of a bending ring and heated to a temperature at which the glass becomes malleable and allows it to sag freely under gravity. The sag continues until the glass's malleability decreases by lowering the temperature. In the present invention's method for bending thin glass layers, the final desired shape of the second glass sheet for laminated window glass is not fully achieved at this stage by the gravity-induced sag bending method.

[0086] Similar to the first glass sheet, the second glass sheet is shaped in one or more directions to have a radius of curvature between 300 mm and 8000 mm. However, the second glass sheet is much thinner than the first glass sheet. The second glass sheet can be 65% thinner than the first glass sheet. For example, the thickness of the first glass sheet can be in the range of 1.4 mm to 2.5 mm; or in the range of 1.6 mm to 2.3 mm. However, the thickness of the second glass sheet can be in the range of 0.2 mm to 1.4 mm; or in the range of 0.5 mm to 1.0 mm. The thickness of the first glass sheet can also be in the range of 1.6 mm to 2.1 mm.

[0087] The first and second preformed glass sheets are then combined and bonded together via an adhesive interlayer 140. The adhesive interlayer may have a thickness ranging from 0.3 mm to 1.8 mm, or from 0.5 mm to 1.0 mm. However, the adhesive interlayer material is typically preferably 0.76 mm thick. Suitable adhesive interlayers that can be used in the methods of the present invention include, but are not limited to, for example, polyvinyl chloride (PVC), polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) (also known as poly(ethylene vinyl acetate) (PEVA)), ethyl methacrylate (EMA), and polyurethane. However, the preferred interlayer for use in the methods of the present invention is polyvinyl butyral (PVB).

[0088] Then, during the "pre-compression" process, the first and second pre-formed glass sheets 120, 160 are joined together with the adhesive interlayer 140. The "pre-compression" process includes removing trapped air between the glass sheets 120, 160 and the adhesive interlayer 140. Air can be removed by applying a vacuum to the combination of the glass sheets and the adhesive interlayer. Alternatively, trapped air can be removed by compression, in which case air is expelled from between the glass sheets and the adhesive interlayer.

[0089] In the final step of the method, glass sheets 120 and 160 are joined together with an adhesive interlayer in a pressurized autoclave process, which laminates the glass sheets and the interlayer into the desired shape for the laminated window glass. That is, the lamination of the glass sheets and the adhesive interlayer is completed using a pressurized autoclave. In the pressurized autoclave, the typical pressure range for the lamination process according to the first method of the invention is between 10 and 16 bar, lasting from 30 to 120 minutes.

[0090] The typical temperature range of the lamination process according to the first method of the present invention is between 100°C and 130°C, lasting for 30 to 120 minutes. That is, the temperature range of the pressure vessel used for the lamination process is lower than the temperature range typically used for window glass lamination.

[0091] Choosing appropriate temperature and pressure parameters allows the intermediate layer, such as polyvinyl butyral (PVB), to form a suitable adhesive bond between the glass sheets. Furthermore, it is preferable to select temperature and pressure parameters in a manner that minimizes slippage within the layered structure, thereby forcing the thinner glass sheet or layer to conform to the shape of the thicker glass sheet or layer.

[0092] The laminated window glass 10 prepared according to the method of the present invention can be bent in one or more directions. The radius of curvature in one or more directions can be, for example, between 300 mm and 8000 mm. When the laminated window glass is bent in two directions, each bending direction is appropriately orthogonal to the other bending direction.

[0093] Once the lamination stage of this method is completed, the laminated window glass 180, such as a vehicle windshield, is removed from the autoclave, cleaned, and packaged for use.

[0094] The inventors have discovered that by using the above method, it is possible to achieve laminated window glass in which the curvature of the outer surface 190 (S4) of the thinner second layer 160 (the inner surface when located in a vehicle) differs from the curvature of the outer surface 195 of the first thicker layer 120 less than the curvature difference of the same layer surfaces in laminated window glass prepared using standard methods and parameters.

[0095] The increased curvature of the surface 190 (S4) of the thinner second layer 160 and the outer surface 195 of the thicker first layer 120 results in a significant reduction in noticeable optical distortion when viewed through the sandwich windshield, as well as in optical power measurements (as described above).

[0096] Table 1 provides a summary of process parameters for, for example, preparing laminated window glass in a pressurized autoclave, according to the first method of the present invention.

[0097] Table 1

[0098]

[0099]

[0100] By using the method described above within the parameter range set in Table 1, the inventors were able to achieve high-quality laminated window glass by taking advantage of the fact that a thinner inner glass sheet is more flexible compared to a thicker outer glass sheet. Using the preferred parameter range also allows the autoclave process to be performed while allowing the interlayer (preferably in the form of PVB) to bond to the glass sheet and providing good lamination performance, while maintaining the rigidity of the PVB. This is an important characteristic of laminated window glass, and a particularly important one for laminated window glass used in vehicles.

[0101] More specifically, it can be seen that by using the method of the present invention, under the normal pressure of a pressurized vessel at 10 bar to 13 bar, by reducing the temperature of the pressurized vessel to a temperature lower than the normal pressurized vessel temperature of 135°C to 140°C, to 90°C to 132°C or even 100°C to 130°C, lamination of two glass sheets with an intermediate layer can be achieved.

[0102] However, most specifically, it has been found that by carefully selecting the parameters required for the autoclave process in the method of the present invention, lamination of the two glass sheets and the intermediate layer for forming a lightweight windshield can be achieved in such a way that the transmitted light power (or visible light distortion) recorded for such laminated window glass is significantly reduced compared to the same value recorded for laminated window glass prepared using standard autoclave conditions.

[0103] Preferably, the optical power recorded by the sandwich windshield prepared using the method of the present invention does not exceed 50% of the value recorded by a standard windshield having a glass layer with a thickness of 2.1 mm.

[0104] The light power recorded by the lightweight laminated window glass prepared by the method of the present invention is also significantly improved compared with the light power recorded by lightweight laminated window glass prepared by conventional means (which typically exceeds 80% to 110% of the light power recorded for a standard windshield).

[0105] Method 2.

[0106] exist Figure 3 The diagram 200 illustrates a second method for preparing laminated window glass, such as a vehicle windshield, according to a first aspect of the present invention.

[0107] In method 2, the first glass sheet 220, such as soda-lime silicate glass (which may be flat), is formed into the desired shape of the windshield as described in method 1 above by means of, for example, bending.

[0108] Next, a second, thinner, flat glass sheet 260 (such as soda-lime silicate glass) is cut into a shape having the desired edge profile. Then, the second glass sheet is shaped into a curved shape that is the same as or smaller than the desired windshield glass using, for example, the gravity or drooping bending method described above, also related to method 1. That is, the desired shape of the second glass sheet is achieved again by a forming method different from that used for forming the first glass sheet for the windshield glass.

[0109] Similar to Method 1, the glass sheet can be shaped to have a radius of curvature between, for example, 300 mm and 8000 mm in one or more directions. The second glass sheet is much thinner than the first glass sheet, and the two glass sheets are formed using different techniques. For example, the thickness of the first glass sheet can be in the range of 1.4 mm to 2.5 mm; or in the range of 1.6 mm to 2.3 mm. However, the thickness of the second glass sheet can be in the range of 0.2 mm to 1.4 mm; or in the range of 0.5 mm to 1.0 mm.

[0110] The first and second shaped glass sheets are then combined and joined together by an adhesive interlayer 240. The adhesive interlayer can again be as described above with respect to method 1, and is preferably polyvinyl butyral (PVB) with a thickness preferably of 0.76 mm. Additional adhesive interlayers that can be used in the methods of the present invention include, but are not limited to, for example, polyvinyl chloride (PVC), ethylene vinyl acetate (EVA) (also known as poly(ethylene vinyl acetate) (PEVA)), ethyl methacrylate (EMA), and polyurethane.

[0111] However, compared with Method 1 above, Method 2 employs a modification such that air is eliminated between the two formed glass sheets and the adhesive interlayer before the "pre-pressing" stage. In Method 2, a thin foil layer 280 is applied between the outer surface (S4) 290 of the second glass sheet that does not contact the adhesive interlayer and the forming mold 285.

[0112] The thin foil layer 280 is preferably a non-adhesive film, which is placed between the second glass sheet 260 and the mold 285 to prevent scratches. For example, suitable thin foils may include, but are not limited to: and Polyester film with trademarks obtained from HostophanFilms or Mitsubishi Polyester Film GmbH.

[0113] The forming mold 285 preferably has dimensions and shape that match the profile of the first glass layer 220. The mold can be made of a suitable material such as plastic, glass, or ceramic.

[0114] However, it is more preferable that the mold is prepared by the same batch process used to prepare the outer glass sheet 220 and thus formed into a glass sheet with substantially the same shape as the first glass sheet. This mold is referred to herein as a slave mold or slave glass.

[0115] Then, it can be like Figure 3 In the arrangement 300 illustrated, the first and second pre-formed glass sheets 220 and 260 are combined with the adhesive interlayer 240 during the "pre-pressing" process, and combined with the thin foil 280 and the subordinate mold or glass 285. That is, the first glass sheet 220 has a face 295 and the subordinate mold or glass 285 with two outer surfaces forming the "pre-pressing" structure, and a second thinner glass sheet 260 is separated from the first glass sheet 220 and the outer glass sheet 285 by the interlayer material 240 on the first glass sheet side and the thin foil layer 280 on the subordinate glass 285 side.

[0116] Then, using, for example, vacuum degassing techniques or pressure roller methods, the air trapped between the glass sheets 220, 260 and the adhesive intermediate layer 240 is removed, as in Method 1.

[0117] Then, a pressure vessel is used to complete the lamination of the glass sheet and the adhesive interlayer. In the second method of the invention, the pressure range for lamination in the pressure vessel is typically between 10 and 13 bar, lasting 30 to 60 minutes. The temperature range for lamination according to the second method is typically between 90°C and 132°C, or even between 100°C and 110°C, lasting 30 to 60 minutes. In a preferred embodiment of the second method according to the invention, the temperature for the lamination process can be in the range of 105°C, and the pressure can be about 10 bar, lasting about 45 minutes.

[0118] In Method 2, the selection of suitable temperature and pressure parameters enables the intermediate layer, such as polyvinyl butyral (PVB), to form a suitable adhesive bond between the glass sheets. That is, the temperature and pressure parameters are preferably selected in such a way that slippage within the layered structure is minimized, thereby forcing the thinner glass sheet or layer to follow the shape of the thicker glass sheet or layer and the shape of the subordinate glass. Furthermore, if a vacuum ring or vacuum bag is used to hold the subordinate glass in place during the "pre-compression" process, it can also be used during the pressurization process.

[0119] Although a pressure vessel is preferred in the lamination process according to the invention, those skilled in the art will understand that it is appropriate and that suitable parameters outlined above for the pressure vessel process can be used to evacuate the vacuum from a vacuum ring or vacuum bag instead of a pressure vessel, using an oven equipped with a vacuum port.

[0120] The laminated window glass thus prepared can be bent in one or more directions. The radius of curvature in each of the one or more directions can be between 300 mm and 8000 mm. When the laminated window glass is bent in two directions, each bending direction is appropriately orthogonal to the other bending direction.

[0121] Once the lamination process is complete, the laminated window glass structure, such as a windshield, can be removed from the pressurized autoclave. The dependent mold or glass 285 and film 280 can then be removed from the first and second laminated glass sheets to obtain a laminated window glass 400 ready for use after cleaning.

[0122] Furthermore, the use of a thin foil layer 280 allows for easy separation of the inner glass layer 260 from the subordinate glass mold 285, and also protects the surface 290 of the inner glass layer and the inner surface 284 of the subordinate glass mold 286 from scratches. Once the subordinate glass mold is separated from the laminated glass layer, it can be reused in a secondary repetition of method 2. The subordinate glass mold can be used again as a subordinate mold, or it can be used as the first glass sheet 220. In this way, method 2 provides the following advantages: since the subordinate glass mold can be reused, excessive waste glass is avoided; furthermore, the laminated window glass prepared by this method has improved optical properties.

[0123] The inventors have discovered that by using the above-described method 2, it is possible to achieve laminated window glass in which the curvature of the inner surface 290 (S4) of the second glass sheet 260 and the curvature of the outer surface 295 of the first glass sheet 220 are substantially or nearly identical.

[0124] That is, by using the method of the present invention, the inventors have discovered that a second, thinner glass sheet (or inner glass) can take the shape of a first, thicker glass sheet (or outer glass).

[0125] The inventors have also discovered that the preferred dependent glass or mold 285 used in the method of the present invention is another formed first glass sheet, which has the same shape as the first glass sheet and can be formed, for example, in the same bending batch process as the first glass sheet.

[0126] The laminated window glass prepared in the embodiments of the present invention described above preferably comprises a soda-lime silicate glass sheet having a composition such as that of clear float glass. For example, the glass sheet may also contain iron oxide as a colorant to provide laminated window glass with sunlight control means.

[0127] Typical sodium-calcium silicate glass compositions may contain, by weight, for example: 69-74% SiO2; 10-16% Al2O3; 0-5% Na2O; 0-6% K2O; 5-14% MgO; 0-2% CaO; and 0.005-2% Fe2O3.

[0128] The glass slide may also contain other additives, such as clarifying agents, which are typically present in amounts of 2% or less. Sodium-calcium silicate glass compositions may also contain other colorants such as CO3O4, NiO, and Se to impart the desired color to the glass composition when viewed under transmitted light.

[0129] Furthermore, the sodium-calcium silicate glass composition used for each glass sheet in the method of the present invention may be the same or different.

[0130] Furthermore, one or more glass sheets used in the method of the present invention can be chemically tempered. Chemical tempering or strengthening involves treating the glass sheet with a potassium salt solution, such as potassium nitrate, wherein the glass sheet is immersed in a temperature in the range of 300°C to 460°C, more preferably in the range of 400°C to 460°C, most preferably in the range of 420°C to 460°C, such as at a temperature of about 450°C. Immersing the glass in a potassium salt causes sodium ions on the glass surface to be replaced by potassium ions from the solution, thereby imparting additional impact resistance to the glass sheet during lamination.

[0131] Furthermore, according to the method of the present invention, the outer surface S1 preferably has a residual compressive stress in the range of 10 MPa to 20 MPa in a region extending, for example, around the perimeter of the windshield.

[0132] That is, for example, the surface compressive stress of the convex surface S1 of the first glass pane 120, 220 of the laminated window glass may have an edge region with residual edge stress, while the net tension is less than 11 MPa and the edge compression is greater than 25 MPa.

[0133] exist Figure 8 A summary flowchart of an example method for preparing laminated window glass, such as a windshield, according to the present invention is provided.

[0134] Initially, a first glass sheet, such as soda-lime silicate glass, is provided in step 321. The soda-lime silicate glass may be transparent or colored. Transparent float glass refers to a glass sheet having a composition as defined by reference in BS EN 572-1 and BS EN 572-2 (2004), which are incorporated herein by reference.

[0135] In step 323, the first glass sheet is cut and substantially shaped into the desired form using conventional techniques such as bending. The glass sheet for transparent float glass can have a thickness ranging from, for example, 1.4 mm to 2.5 mm. In step 325, the edges of the glass sheet (also called the preform) are ground or “edge-finished,” and then the glass sheet is cleaned.

[0136] After cleaning, one or both main surfaces of the glass sheet can be printed according to the requirements of the final product. For example, if the final product is a vehicle windshield, a layer of ink that may be optically opaque and / or conductive can be printed around the perimeter of the glass sheet to form a masking band as is common in the art.

[0137] In step 327, the glass sheet is heated to its softening temperature in a suitable furnace. The heated and softened glass can then be bent between a pair of complementary forming members to give the outer sheet the desired curvature. Bending allows for precise control of the glass sheet's shape. Examples of bending devices and operations are described in WO2005 / 033026A1 and EP0677486A2. Once bent, a cut sheet, such as clear float glass, will continue as the first glass sheet for laminated windows, such as windshields.

[0138] To control the stress in the first glass sheet, the upper and / or lower bending forming members can be heated to control the residual edge stress and / or edge compression of the outer sheet. By selecting the required temperature of the upper and / or lower bending forming members, an outer sheet with an edge region having residual edge stress, such as a net tension of less than 11 MPa and an edge compression of more than 25 MPa, can be produced.

[0139] Residual surface stress can also be controlled by introducing cooling air around the periphery of the bent glass sheet shortly after the bending operation is completed and before the bent plate is cooled to room temperature.

[0140] After guiding cooling air to the edge of the glass sheet for a suitable duration to generate the required residual stress in the cooled, bent glass sheet, the bent glass sheet is controlled to room temperature in a suitable annealing furnace in step 329.

[0141] Bending a series of glass sheets can form part of a batch processing, in which many first glass sheets are bent sequentially. In this way, during the autoclave process described below, a glass sheet from that batch can be used as the first glass sheet in a laminated window, while another glass sheet from the same batch can be used as a subordinate glass mold.

[0142] The first glass sheet can be bent in one or more directions. The curvature in one or more directions can have a radius of curvature between 300 mm and 8000 mm.

[0143] The second pane of the laminated window glass is manufactured as follows.

[0144] In step 331, a second glass sheet, such as soda-lime silicate glass, is provided. The soda-lime silicate glass may be transparent or colored, or it may be modified. In this example, a transparent float glass sheet is provided in step 331.

[0145] The second glass sheet of soda-lime silicate glass may preferably have a thickness of, for example, 0.7 mm or less, and is cut in step 333 to have the same perimeter as the unbent first glass sheet (or outer blank). The cut second glass sheet of soda-lime silicate glass may also be referred to as the inner blank before bending. The second glass sheet of soda-lime silicate glass may, for example, have a thickness between 0.2 mm and 1.4 mm. Alternatively, the second glass sheet of soda-lime silicate glass may, for example, have a thickness between 0.5 mm and 1 mm.

[0146] In step 335, the second glass sheet is preferably subjected to appropriate edge processing and cleaning before being bent.

[0147] In step 337, the second glass sheet is preferably placed on a suitable annular mold to support it near its periphery. The second glass sheet is then heated to a sufficient temperature to cause the soda-lime silicate glass to soften and sag under gravity. This process is commonly referred to as gravity bending or sag bending. The glass sags or bends to a shape close to that of the first glass sheet. However, at this point, the curvature of the second glass sheet may differ from that of the first glass sheet.

[0148] In step 339, the temperature is reduced to room temperature using controlled cooling to anneal the bent second glass sheet.

[0149] In step 340, the bent second glass sheet of sodium-calcium silicate glass can be chemically strengthened using, for example, an ion exchange process, wherein sodium ions in the second glass sheet are typically chemically exchanged for potassium ions.

[0150] It is also conceivable that the curved second glass sheet of soda-lime silicate glass can be heat-tempered, even if it is difficult to heat-temper glass sheets with a thickness of 1 mm or less.

[0151] In step 341, a first bent glass sheet (after steps 321-329) and a second bent glass sheet (after steps 331-340) are provided.

[0152] In step 342, a pair of curved first and second glass sheets are cleaned. In step 344, an intermediate layer material sheet, such as polyvinyl butyral, with a thickness between 0.3 mm and 1.5 mm, may be placed between the first and second glass sheets.

[0153] In this particular example, although other suitable adhesive interlayer materials may be used, a 0.76 mm thick polyvinyl butyral (PVB) sheet is preferred as the interlayer material.

[0154] Alternatively, in step 345, in addition to placing a suitable intermediate layer between the curved first and second glass sheets, a thin foil layer may be placed on the side of the curved second glass sheet opposite to the intermediate layer. Furthermore, a mold in the form of another curved first glass sheet (or preform) may be placed on the side of the thin foil layer opposite to the curved second glass sheet.

[0155] Then, in step 346, the first and second glass sheets with a PVB sheet between them, with or without an additional foil layer and with a subordinate mold (such as an additional bent first glass sheet), are subjected to autoclaving treatment using the suitable conditions defined above with respect to method 1 or method 2, to connect the first and second glass sheets by means of the PVB sheet used to bond the two glass sheets together.

[0156] Then, in step 347, the foil layer and the slave mold are removed. In step 349, if the slave mold is in the form of another first glass sheet, it can be cleaned and recycled back to step 341, either as a bent first glass sheet for lamination or again as a slave mold.

[0157] The laminated window glass produced in step 348 is cleaned and inspected before being delivered to the customer.

[0158] result

[0159] In order to provide evidence of the beneficial effects proposed by the method according to the first aspect of the invention, deflection measurements using curvature testing were examined of the laminated window glass and individual glass panes.

[0160] As is well known, in the field of optics, the curvature of the two surfaces of a transparent object, especially the difference in curvature, provides the optical power of the transparent object.

[0161] Deflection measurement is a reliable method for measuring the curvature of smooth surfaces. In laminated window glass, if the inner and outer (or first and second) glass panes can have different shapes, measures must be taken when analyzing the window glass to suppress signals from the "back" surface (i.e., the surface not intended for analysis). This can be achieved by using black tape.

[0162] The deflection measurement test method adopts sensor technology based on the principle of measuring phase deflection.

[0163] In deflection measurement methods, a sine-shaped stripe pattern is projected onto a whiteboard to calculate the local slope of a surface. A camera observes the reflection of this pattern through the surface being measured. The local slope of the surface can be directly calculated from the distortion of the observed stripe pattern. This technique has advantages over distance measurement methods because the data only needs to be differencing once for curvature calculation. Therefore, the amplification of high-frequency noise is reduced compared to distance measurement data (which requires differencing twice).

[0164] Therefore, the deflection measurement method used for measuring the laminated window glass prepared according to the method of the present invention is performed using a measurement system obtained from 3D-Shape GmbH. Such a system is also available, for example, from ISRA VISION AG.

[0165] exist Figure 4 The illustration shows an example of a measurement describing the curvature of a single pane or layer of glass in a laminated window, such as a windshield. Figure 4 In the illustration, the vertical axis represents the curvature value (in meters) measured along the vertical line of the windshield as shown in the inset. -1 (In units). The horizontal axis measures the distance from the top to the bottom of the windshield (in mm). The darker line (A) in the figure relates to measurements of the first or outer glass, indicating a unique structure. The lighter line (B) in the figure relates to measurements of the surface of the second or inner glass, which is smooth at the center but has a significant curvature change in the upper part of the glass layer. Discussing the background of these structures is not the purpose of this invention. For the use of the techniques related to this invention, it is sufficient for the glass sheet to have different properties depending on the forming process involved in its formation.

[0166] According to the present invention, two sample sandwich windshields were prepared according to method 2 described above. The windshields were analyzed by visual inspection, and along each sample (e.g. Figure 4 The curvature values ​​were measured on the same line shown in the inset. The outer (or outer) surface of the laminated windshield (i.e., the surface that will be exposed to the outside of the vehicle during installation), surface S1, was measured with the inner surface S4 suppressed. The inner surface of the laminated windshield, surface S4, was also measured with the outer surface S1 suppressed.

[0167] Figure 5 An example of measuring the curvature of two layers of glass is provided. By using optical methods, the curvature of the outer surface S1 of the outer glass and the curvature of the outer surface S4 of the inner glass (both measured in units of 1 / m) are expressed as functions of the vertical position along a vertical line on the glass.

[0168] Figure 5 The results of the curvature measurement are provided. Figure 5In the diagram, the darker curve (C) represents the curvature value of the outer (S1) surface, while the lighter curve (D) represents the corresponding inner surface S4. From... Figure 5 It is clear that, aside from measurement uncertainties, the two surfaces "fit" together; that is, the curvature of each of surfaces S1 and S4 follows a common shape. In other words, through analysis... Figure 5 The data shown reveals that the average difference in curvature between surfaces S1 and S4 is only 0.0101m. -1 The maximum difference was only 0.026m. -1 Therefore, the data confirms that the curvature of the two surfaces is almost identical.

[0169] Therefore, from Figure 5 It can be seen that the two surfaces exhibit almost identical structures; conversely, Figure 4 An equivalent measurement of a single glass layer is illustrated, where there are significant differences in curvature between the glass layers.

[0170] Due to the curvature matching of the inner S4 and outer S1 surfaces of the windshield, the transmission optics of the sandwich windshield prepared according to the present invention are significantly improved. That is, the curvature value of the outer glass plate S1 is substantially matched with the curvature value recorded for the inner glass plate S4 produced using the method of the present invention, resulting in minimal lens effect, transmission optical distortion, or turbidity appearing on the sandwich windshield.

[0171] From the Figure 6 and Figure 7 Visual comparison with the sandwich windshields described herein shows a clear improvement in transmission optical distortion or turbidity in the sandwich windshields produced by the method of the present invention.

[0172] Figure 7 The image shows a sandwich lightweight windshield prepared according to the present invention, wherein an outer glass sheet (220) is formed using a bending method to form a laminate, while an inner glass sheet (260) is formed using an alternative method (i.e., a gravity-induced bending method), and the two glass sheets are laminated according to the method of the present invention.

[0173] Figure 6 This is an illustration of a lightweight sandwich windshield manufactured using known techniques, in which an outer glass sheet is fully shaped into the desired form through direct, full-surface contact with a mold, and an inner glass sheet is prepared by gravity bending.

[0174] from Figure 6 As can be seen, the windshield has a mottled appearance, with noticeable uneven gray shadows on its surface. These gray shadows are particularly pronounced in the interior area of ​​the windshield. The rapid changes in the gray tint of the windshield indicate rapid changes in light power within the windshield, thus increasing the variety and number of undesirable optical effects.

[0175] In contrast, from the perspective of Figure 7 Visual inspection of the laminated windshield reveals that it exhibits a more uniform coloration, free of mottled gray spots. As a result, the windshield's transmitted optics are improved.

[0176] To evaluate the distortion effect of the sandwich windshield produced by the method of the present invention, the transmitted light through the windshield was also measured using an instrument system capable of measuring the optical performance of the entire windshield in millidiopters (mdpts).

[0177] The instrument system used is capable of measuring optical power. Many instruments on the market can perform this function. These systems operate by projecting light from a single light source through a windshield onto a white screen. A camera then takes a photograph of the windshield (called a "shadow image") and calculates the windshield's optical power in milliphotometers.

[0178] In the evaluation below, only the power causing deflection and distortion in the vertical direction (i.e., the vertical component) was measured. As previously stated, the instrument system was operated according to protocol ECE R43 or by means of a device manufactured by ISRA Vision AG or according to appropriate VDA recommendations (such as VDA 312 recommendation (March 2015), which relates to "Requirements for Test Equipment for Inspection of Visual Distortion at Transmitted Window").

[0179] Therefore, the optical power of the sandwich windshield prepared according to the present invention was measured using a typical mounting angle of 61° to the vertical direction. The range of optical power values ​​measured according to the so-called viewing zone A (as described in ECE R43 or VDA 312) is reported.

[0180] The optical power of a series of interlayer windshields was recorded, and shadow images were captured as described above. The evaluation results are provided in Table 4.

[0181] Table 4.

[0182]

[0183] Therefore, it can be seen that, according to the method of the present invention, lightweight windshields with improved visual appearance and optical parameters can be produced.

Claims

1. A method for preparing laminated window glass, comprising the following steps: i) A first glass sheet is provided through a first process, the first glass sheet being formed into a desired shape having a first thickness; ii) A second glass sheet is provided by a second process, the second glass sheet being formed into a desired shape having a second thickness, wherein the thickness of the first glass sheet is different from the thickness of the second glass sheet; iii) Provide an intermediate layer located between the first and second glass sheets; as well as iv) Laminate the first and second glass sheets and the intermediate layer together at temperatures and pressures sufficient to bond the interlayer material to the glass sheets; v) During lamination, a mold, which has a shape substantially identical to that of the first glass sheet and is prepared in the same batch process as the first glass sheet, is applied to the second glass sheet to bond the interlayer material to the two glass sheets, such that after lamination, the shape of the second glass sheet is substantially identical to that of the first glass sheet, and the mold has the form of a third glass sheet with the same thickness as the first glass sheet; wherein the method further includes the following steps: vi) Prior to lamination, a foil layer is provided between a second glass sheet and a mold that is substantially the same shape as the first glass sheet, wherein the foil layer comprises a non-adhesive film.

2. The method according to claim 1, wherein in step iv), lamination occurs at a temperature in the range of 90°C to 132°C and a pressure in the range of 8 bar to 16 bar.

3. The method according to claim 1 or 2, wherein in step iv), lamination occurs at a temperature in the range of 100°C to 110°C; and The intermediate layer contains polyvinyl butyral (PVB).

4. The method according to claim 1 or 2, wherein the first step of forming the first glass sheet into the desired shape is performed by bending, and / or wherein the thickness of the first glass sheet is in the range of 1.4 mm to 2.5 mm.

5. The method according to claim 1 or 2, wherein the second step of forming the second glass sheet into the desired shape is performed by gravity-induced bending, and / or wherein the thickness of the flat second glass sheet is in the range of 0.2 mm to 1.4 mm.

6. The method according to claim 1 or 2, wherein the mold is a bent glass sheet; and / or wherein the thickness of the third glass sheet is in the range of 1.4 mm to 2.5 mm.

7. The method of claim 6, wherein the first and third glass sheets are prepared in separate bending batch processing.

8. The method according to claim 1 or 2, wherein the thickness of the foil layer is in the range of 0.05 mm to 0.2 mm.

9. The method according to claim 8, wherein the non-adhesive film is a non-adhesive polyester film.

10. The method of claim 6, further comprising the step of: vii) Remove the third glass sheet and the foil layer from the laminated first and second glass sheets.

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