A vehicle window and a method for manufacturing a vehicle window

Abstract

The invention relates to a method for manufacturing a vehicle window comprising the steps of supplying a polyvinyl butyral (PVB) film, cutting the supplied film to a predetermined length and thickness, and laminating it at an angle between an outer glass layer and an inner glass layer. The method for manufacturing a vehicle window further comprising a step where the transverse cross-section of the supplied flat PVB film extends at an angle and is plastically shaped over a conical drum.

Description

[0001] A VEHICLE WINDOW AND A METHOD FOR MANUFACTURING A VEHICLE WINDOW

[0002] TECHNICAL FIELD

[0003] The present invention relates to an interlayer film for laminated glass used to obtain laminated glass. Moreover, the present invention relates to vehicle glass prepared with an interlayer film for laminated glass.

[0004] BACKGROUND OF THE ART

[0005] Laminated glass, known for its excellent safety characteristics, generally produces only a small amount of scattered glass fragments even when broken due to external impacts. For this reason, laminated glass is widely used in automobiles, railway vehicles, aircraft, ships, buildings, etc. Laminated glass is produced by placing a pair of glass sheets with an interlayer film between them.

[0006] Additionally, laminated glass used in automobiles may incorporate a technology known as a head-up display (HUD). In a HUD, it is possible to display measured information such as speed, temperature, and RPM on the windshield of a vehicle, allowing the driver to perceive the display as being in front of the windshield. The placement of the interlayer films in laminated glass becomes crucial since it affects the driver's field of vision.

[0007] EP3604251A1 relates to an interlayer film for laminated glass used to significantly suppress double images in laminated glass. The EP3604251A1 publication describes an interlayer film for laminated glass that has a thicker structure at one end and a thinner structure at the other end, corresponding to a display region of a head-up display. When calculating the first partial wedge angles 01 in the first partial regions of 80 mm, each centered at selected points in the connecting direction, and the second partial wedge angles 02 in the second partial regions of 40 mm, each centered at selected points in the connecting direction, the maximum value of 101 -021 among all values of |01-02| is 0.2 mrad or less, and the interlayer film generally has a wedge angle of 0.1 mrad or more. BRIEF DESCRIPTION OF THE INVENTION

[0008] The objective of the invention is to provide a polyvinyl butyral (PVB) film with high structural strength placed between laminated glass used in vehicles.

[0009] In order to achieve the above objective, the invention relates to a vehicle window manufacturing method that comprising the steps of supplying a polyvinyl butyral (PVB) film, cutting the supplied film to a predetermined length and thickness, and laminating it at an angle between an outer glass layer and an inner glass layer. The method for manufacturing a vehicle window includes a step where the transverse cross-section of the supplied flat PVB film extends at an angle and is plastically shaped over a conical drum. As a result, the PVB film moves between drawing rollers and wraps around the heated cone, where the temperature of the cone softens the PVB, creating a high tensile rate, causing the regions of the PVB following the larger diameter of the cone to stretch and thin out, while the regions following the smaller diameter do not stretch and maintain their original thickness.

[0010] In a preferred embodiment of the invention, the drum is heated to a temperature between 40 and 80 degrees Celsius duringthe shaping of the film. In this way, the shaping of the film on the drum is facilitated.

[0011] In a preferred embodiment of the invention, the heated film is cooled at the drum's exit by a cooling device. In this way, the film is cooled, and the appropriate shaping process is applied.

[0012] In a preferred embodiment of the invention, the film is stretched between an entry drum and an exit drum duringthe conical plastic shapingof the film. Thus, a PVB film resistant to tensile forces is applied within the laminated glass structure.

[0013] In a preferred embodiment of the invention, the initial thickness of the PVB film is supplied to be a maximum of 1 ,52 mm. In this way, the thickness of the applied PVB film enhances the mechanical strength of the glass.

[0014] In a preferred embodiment of the invention, only one edge of the PVB film is thinned by plastic shaping, so that the resulting thickness is at least 0,65 mm. Thus, it is ensured that the film is placed at an angle within the laminated glass, and the process time is reduced. In a preferred embodiment of the invention, the PVB film is stretched by a stretching apparatus formed by a plurality of consecutively positioned crosswise drums. Thus, any deformation of the film is prevented.

[0015] In a preferred embodiment of the invention, the PVB film is wound onto a roll from one end to form a feed roll. In this way, the PVB film is preserved until the step where it is applied to the glass during the production process.

[0016] In a preferred embodiment of the invention, the first diameter of the conical drum is at least 300 mm, and the second diameter is at most 2000 mm. In this way, an angled PVB film structure is obtained.

[0017] In a preferred embodiment of the invention, the conical drum is made of a metal material. Thus, the shaping of the PVB film is facilitated.

[0018] In a preferred embodiment of the invention, the conical drum has an entry drum and an exit drum, and the rotation axes of the entry and exit drums are placed at an angle on a rotational plane perpendicular to the rotation axis of the conical drum. In this way, the PVB film is properly held and drawn in a straight direction.

[0019] In a preferred embodiment of the invention, the conical drum comprises a plurality of spaced- apart heating elements. In this way, the shaping of the PVB film through heating is facilitated.

[0020] In a preferred embodiment of the invention, the ratio between the first angle value of the supplied PVB film and the wedge angle of the laminated film is between 0,3 and 0,7.

[0021] In a preferred embodiment of the invention, the temperature difference between the shaping temperature and the cooling temperature is between 15 and 55 degrees Celsius. In this way, a PVB film applied to vehicle glass with high structural strength is obtained.

[0022] BRIEF DESCRIPTION OF THE FIGURES

[0023] Figure 1 shows a schematic representation of the production apparatus forthe vehicle window of the invention. Figure 2 shows a schematic side view of the vehicle window of the invention.

[0024] Figure 3 shows a schematic representation of the geometric form of the interlayer PVBfilm for the vehicle window of the invention.

[0025] DETAILED DESCRIPTION OF THE INVENTION

[0026] In this detailed description, the development subject to the invention is described with reference to examples, without any limitation, and only to provide a better understanding of the subject.

[0027] Figure 1 shows a schematic representation of the production apparatus forthe vehicle window of the invention. A film (2) containing PVB used as an interlayer in the production apparatus for obtaining a vehicle window is provided. The supplied PVB film (2) has an initial thickness of at most 1 ,52 mm, preferably 1 ,14 mm. The PVB film is wrapped from an entry drum (10) onto a conical drum (20). The first diameter of the conical drum (20) is at least 300 mm, and the second diameter is at most 2000 mm. The conical drum (20) is made of metal material and is equipped with both an entry drum (10) and an exit drum (30), where the rotation axes of the entry and exit drums (10, 30) are positioned at an angle in a rotational plane perpendicular to the rotation axis of the conical drum (20). A plurality of heating elements (22) spaced apart on the conical drum (20) are provided. Once the PVBfilm (2) is fully wrapped around the conical drum (20), the heating elements (22) are activated to heat the PVB film (2), enabling its plastic shaping over the conical drum (20). Only one edge of the PVB film (2) is thinned during the angled placement, down to a thickness of 0.65 mm. During the process, the PVB film (2) is heated up to a range of 40 to 80 degrees Celsius. The heated PVB film (2) is removed from the exit drum (30) and transferred to a cooling device (40) where it is cooled to room temperature. The cooled PVB film (2) is stretched in a stretching apparatus (50). The stretching apparatus (50) consists of a plurality of drums (52) positioned crosswise and spaced apart. The PVB film (2) passing through the drums (52) in the stretching apparatus (50) is stretched and wound into a roll (60), making it ready for application onto the vehicle window.

[0028] Figure 2 shows a schematic side view of the vehicle window of the invention. The vehicle window comprises an outer glass layer (3) facing the external environment, an inner glass layer (1 ) facing inward, and an interlayer provided between them. The interlayer is composed of the PVB film (2), which enhances the structural strength of the vehicle window. In the interlayer film for laminated glass, the initial point is taken as a position 4 cm away from one end of the display region, and another point is selected 4 cm away from the opposite end, with points selected at 2 mm intervals. The selection of points starts from one end and continues at 2 mm intervals towards the opposite end. Around each selected point, the first partial wedge angle 01 is calculated in the first partial regions of 80 mm. The first partial regions are defined as (X1 ). In the interlayer film for laminated glass, the second partial wedge angle 02 is calculated in the second partial regions of 40 mm, corresponding to the center of each selected point in the direction connecting the first and second ends. The second partial regions are defined as (X2). A 38 mm overlap is present between two adjacent second partial regions (X2). Subsequently, 101 -021 is calculated for the first partial region (X1 ) and the second partial region (X2), centered at the same point. Specifically, |01 -02| is calculated from the point starting at 0 cm from one end to the other end in the first partial region (X1 ) of 0 cm to 8 cm in the display region and in the second partial region from 2 cm to 6 cm of one end to the other end in the display region. This calculation is performed at all points. Thus, an interlayer structure with high mechanical strength is provided within the vehicle window.

[0029] Figure 3 shows a schematic representation of the geometric form of the interlayer PVBfilm for the vehicle window of the invention. As shown in Figure 3, the PVB film (2) has a wedge-like form. In the interlayer PVB film (2) for laminated glass, to effectively suppress double images, the maximum value among the |01-02| values at 250 points are preferably 0.2 mrad or less, more preferably 0.15 mrad or less, even more preferably 0.1 mrad or less, and most preferably 0.05 mrad or less. The first partial wedge angle (01) is an internal angle at the intersection of the following two lines. The first partial wedge angle (01) can be approximately calculated as follows. The thickness of the interlayer film is measured at both ends of the first partial region (X1). Based on the result (the absolute difference between the thickness at one end of the first partial region (X1 ) and the thickness at the other end of the first partial region (XI ) (pm) 80 (mm)), the first partial wedge angle (01 ) is approximately calculated.

[0030] REFERENCE NUMBERS

[0031] 1 . Inner Glass Layer

[0032] 2. Film

[0033] 3. Outer Glass Layer

[0034] 10. Entry Drum

[0035] 20. Conical Drum 22. Heating Element

[0036] 30. Exit Drum

[0037] 40. Cooling Device

[0038] 50. Stretching Apparatus 52. Drum

[0039] 60. Roll

[0040] 01 . First Partial Wedge Angle

Claims

CLAIMS1 . A method for manufacturing a vehicle window, comprising the steps of supplying a polyvinyl butyral (PVB) film (2), cutting the supplied film (2) to a predetermined length and thickness, and laminating it at an angle between an outer glass layer (3) and an inner glass layer (1 ) comprising the step of the transverse cross-section of the supplied flat PVB film (2) extends at an angle and is plastically shaped over on a conical drum (20).

2. The method for ma nufactu ring a vehicle window according to claim 1 , wherein the conical drum (20) is heated to a temperature between 40 and 80 degrees Celsius during the shaping of the film (2).

3. The method for manufacturing a vehicle window according to any of the preceding claims, wherein the heated film (2) is cooled by a cooling device (40) at the exit of the conical drum (20).

4. The method for manufacturing a vehicle window according to any of the preceding claims, wherein the film (2) is stretched between an entry drum (10) and an exit drum (30) during the conical plastic shaping of the film (2).

5. The method for manufacturing a vehicle window according to any of the preceding claims, wherein the PVB film (2) is supplied with an initial thickness of at most 1 ,52 mm.

6. The method for manufacturing a vehicle window according to claim 5, wherein only one edge of the PVB film (2) is thinned by plastic shaping so that the resulting thickness is at least 0,65 mm.

7. The method for manufacturing a vehicle window according to any of the preceding claims, wherein the PVB film (2) is stretched by a stretching apparatus (50) formed by a plurality of consecutively positioned crosswise drums (52).

8. The method for manufacturing a vehicle window according to any of the preceding claims, wherein the PVB film (2) is wound onto a roll (60) from one end to form a feed roll.

9. The production apparatus used in the method according to any of the preceding claims, wherein the conical drum (20) has a first diameter of at least 300 mm and a second diameter of at most 2000 mm.

10. The production apparatus used in the method according to any of the preceding claims, wherein the conical drum (20) is made of metal material.

11. The production apparatus used in the method according to any of the preceding claims, wherein the conical drum (20) has an entry drum (10) and an exit drum (30), and the rotation axes of the entry and exit drums (10, 30) are placed at an angle on a rotational plane perpendicular to the rotation axis of the conical drum (20).

12. The production apparatus used in the method according to any of the preceding claims, wherein the conical drum (20) comprises a plurality of spaced-apart heating elements (22).

13. The production apparatus used in the method according to any of the preceding claims, wherein the ratio between the first angle value of the supplied PVB film (2) and the wedge angle of the laminated film is between 0,3 and 0,7.

14. The production apparatus used in the method according to any of the preceding claims, wherein the temperature difference between the shaping temperature and the cooling temperature is between 15 and 55 degrees Celsius.

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