JP7618922B2 - Manufacturing method for laminated glass for vehicle windows - Google Patents

Description

The present invention relates to a method for manufacturing laminated glass for vehicle windows.

Technology for enclosing a functional film such as a light control film within laminated glass is known. For example, there is laminated glass in which a first glass plate, a first interlayer film, a light control film, a second interlayer film, and a second glass plate are laminated in this order (see, for example, Patent Document 1). In this laminated glass, the first glass plate and the second glass plate are formed into a three-dimensional curved surface.

When manufacturing laminated glass having a functional film between glass sheets with such curved surfaces, wrinkles are likely to occur, for example, at the periphery of the functional film. Patent Document 1 proposes a preparatory process in which a heat forming process is carried out to deform the light control film from a flat state into a shape that matches the three-dimensional curved surface of the laminated glass.

JP 2019-85277 A

However, the thermoforming process is carried out by pressing a solid mold with a surface shape that matches the shape of the light-control film, which requires processing and jig management that are suited to each desired curved shape, making it difficult to flexibly accommodate multiple types of curved shapes.

The present invention was made in consideration of the above points, and aims to provide a manufacturing method for laminated glass for vehicle windows that can accommodate multiple types of curved surface shapes and has excellent quality.

The manufacturing method of laminated glass for vehicle windows according to one embodiment of the disclosure is a manufacturing method of laminated glass for vehicle windows in which first and second glass sheets are bonded via an intermediate film, and includes a lamination process of arranging a functional film including a resin film between first and second curved plate-like bodies to form a laminate, a molding process of heating the functional film to a temperature equal to or higher than the softening point and lower than the melting point of the resin film to form a curved functional film, and a first compression process of arranging the intermediate film and the curved functional film between the first and second glass sheets and compressing them, in which the area of the main surface of the first curved plate-like body is larger than the area of the first main surface of the functional film that faces the main surface of the first curved plate-like body, and the area of the main surface of the second curved plate-like body is larger than the area of the second main surface of the functional film that faces the main surface of the second curved plate-like body.

According to one embodiment of the disclosure, a manufacturing method for laminated glass for vehicle windows that is compatible with multiple types of curved surface shapes and has excellent quality can be provided.

FIG. 1 is a diagram illustrating a laminated glass for vehicle windows according to an embodiment of the present invention. 1 is a perspective view illustrating a laminated glass for a vehicle window according to an embodiment of the present invention. 1A to 1C are diagrams illustrating a bending method for a functional film. FIG. 2 is a diagram illustrating a method for producing a laminated glass for a vehicle window according to the present embodiment.

Below, the mode for carrying out the invention will be explained with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted. Also, in each drawing, some sizes and shapes may be exaggerated to make the contents of the present invention easier to understand.

Note that a vehicle is typically an automobile, but also refers to any moving object having laminated glass for vehicle windows, including trains, ships, aircraft, etc.

In addition, a plan view refers to a specified area of the laminated glass for vehicle windows viewed from the normal direction of the surface of the laminated glass for vehicle windows facing the vehicle exterior, and a planar shape refers to the shape of a specified area of the laminated glass for vehicle windows viewed from the normal direction of the surface of the laminated glass for vehicle windows facing the vehicle exterior.

[Laminated glass for vehicle windows]
Fig. 1 is a diagram illustrating a laminated glass for vehicle windows according to this embodiment, and Fig. 1(a) is a schematic diagram illustrating a state in which the laminated glass for vehicle windows is attached to a vehicle and is visually confirmed from outside the vehicle interior. Fig. 1(b) is a cross-sectional view taken along line A-A in Fig. 1(a). Fig. 2 is a perspective view illustrating the laminated glass for vehicle windows according to this embodiment.

As shown in Figures 1 and 2, the laminated glass for vehicle windows 10 has a glass plate 11, a glass plate 12, an intermediate film 13, a shielding layer 14, and a curved functional film 15. The glass plates 11 and 12 are bonded together via the intermediate film 13. The glass plate 11 is disposed on a first side (negative side of the Z axis) that faces the inside of the vehicle when the laminated glass for vehicle windows 10 is installed in a vehicle, and the glass plate 12 is disposed on a second side (positive side of the Z axis) that faces the outside of the vehicle when the laminated glass for vehicle windows 10 is installed in a vehicle. The shielding layer 14 is provided as necessary.

Here, in a plan view of the laminated glass for vehicle windows 10, of the two line segments connecting the midpoints of the two pairs of opposing sides, the direction of the shorter line segment is the first direction, and the direction of the longer line segment is the second direction. In the example of FIG. 1(a), the Y-axis direction is the first direction, and the X-axis direction (direction of line A-A) is the second direction. In the example shown in FIG. 1 and FIG. 2, the first direction and the second direction are perpendicular to each other. Note that when the lengths of the two line segments connecting the midpoints of the opposing sides are the same, either one may be the first direction and the second direction, but the direction of the line segment that intersects with the shortest side of the laminated glass for vehicle windows 10 may be the first direction, and the other may be the second direction.

The laminated glass 10 for vehicle windows has, for example, a complex curved shape curved in both a first direction and a second direction. However, the complex curved shape is not limited to a shape curved in two directions, the first direction and the second direction, but includes a shape curved in two or more different directions. Alternatively, the laminated glass 10 for vehicle windows may have a single curved shape curved in only the first direction or only the second direction. Note that the single curved shape is not limited to a shape curved in only the first direction or only the second direction, but includes a shape curved in only one direction.

The laminated glass 10 for vehicle windows is preferably curved so as to be convex toward the outside of the vehicle (the second side). In Figs. 1 and 2, the laminated glass 10 for vehicle windows is rectangular in plan view, but the laminated glass 10 for vehicle windows is not limited to a rectangular shape and may be any shape including a trapezoidal shape.

The laminated glass 10 for vehicle windows can be used, for example, in vehicle windshields, rear windows, roof windows, front side windows, rear side windows, front bench windows, rear quarter windows, extra windows, etc.

Glass plate 11 is an interior glass plate that becomes the interior side (first side) of the vehicle when laminated glass for vehicle windows 10 is installed in a vehicle. Glass plate 12 is an exterior glass plate that becomes the exterior side (second side) of the vehicle when laminated glass for vehicle windows 10 is installed in a vehicle. Glass plate 11 is a representative example of a first glass plate according to the present invention, and glass plate 12 is a representative example of a second glass plate according to the present invention.

In the laminated glass 10 for vehicle windows, the minimum value of the radius of curvature is preferably 500 mm or more and 100,000 mm or less. The radii of curvature of the glass plates 11 and 12 may be the same or different. When the radii of curvature of the glass plates 11 and 12 are different, the radius of curvature of the glass plate 11 is smaller than the radius of curvature of the glass plate 12.

The glass plates 11 and 12 are a pair of glass plates facing each other, and the intermediate film 13 and the curved function film 15 are located between the pair of glass plates. The glass plates 11 and 12 are fixed together with the intermediate film 13 and the curved function film 15 sandwiched between them.

The intermediate film 13 is a film that bonds the glass plate 11 and the glass plate 12. The intermediate film 13 has, for example, a first intermediate film 131 that bonds to the glass plate 11 and a second intermediate film 132 that bonds to the glass plate 12. In addition to the first intermediate film 131 and the second intermediate film 132, a frame-shaped intermediate film that is located between the first intermediate film 131 and the second intermediate film 132 and surrounds the outer peripheral side surface of the curved functional film 15 may be provided. When there is no need to particularly distinguish between the first intermediate film 131 and the second intermediate film 132, they are simply referred to as intermediate film 13.

The outermost contour of the object in a plan view is referred to as the periphery, and the area with a width that includes the periphery is referred to as the peripheral portion. In addition, the surface that includes the periphery and connects one main surface of the object to the other main surface is referred to as the outer periphery side surface.

It is preferable that the outer peripheral side of the interlayer 13 is edge-treated. In other words, it is preferable that the outer peripheral side of the interlayer 13 is treated so that it does not protrude significantly from the outer peripheral side of the glass sheets 11 and 12. If the outer peripheral side of the interlayer 13 protrudes from the outer peripheral side of the glass sheets 11 and 12 by an amount of 150 μm or less, it is preferable in terms of not impairing the appearance. However, when the laminated glass 10 for vehicle windows is a side glass, the lower edge is hidden by the door panel, so edge treatment of the lower edge of the interlayer 13 is not essential. Details of the glass sheets 11, 12, and the interlayer 13 will be described later.

The shielding layer 14 is an opaque layer, and can be provided, for example, in a strip shape along the periphery of the laminated glass 10 for vehicle windows. The shielding layer 14 is, for example, an opaque colored ceramic layer, and may be any color, but dark colors such as black, brown, gray, and dark blue are preferred, and black is more preferred. The shielding layer 14 may be a colored intermediate film or film with light-shielding properties, a combination of a colored intermediate film and a colored ceramic layer, or a layer with a light-adjusting function. The colored film may be integrated with an infrared reflective film, etc.

The width of the shielding layer 14 in plan view is, for example, about 10 mm to 250 mm, preferably 20 mm to 220 mm, and more preferably 30 mm to 200 mm. The presence of the opaque shielding layer 14 in the laminated glass for vehicle windows 10 can prevent the adhesive made of a resin such as urethane that holds the peripheral portion of the laminated glass for vehicle windows 10 to the vehicle body from deteriorating due to ultraviolet rays. In addition, when a power supply member such as a bus bar or an electrode is electrically connected to the peripheral portion of the curved functional film 15, the power supply member electrically connected to the curved functional film 15 can be concealed so as to be difficult to see from the outside and/or inside of the vehicle.

In the example of Figures 1 and 2, the shielding layer 14 is provided on the peripheral portion of the interior surface of the glass plate 12, but the shielding layer 14 may be provided on the peripheral portion of the interior surface of the glass plate 11 as necessary, or on both the peripheral portion of the interior surface of the glass plate 11 and the peripheral portion of the interior surface of the glass plate 12. Alternatively, the shielding layer 14 may not be provided.

The curved functional film 15 is enclosed in the intermediate film 13. The curved functional film is a functional film that is originally flat and then curved, and refers to the film after hardening. The surface of the curved functional film 15 facing the glass plate 11 is covered with a first intermediate film 131, and the surface of the curved functional film 15 facing the glass plate 12 is covered with a second intermediate film 132. The curved functional film 15 may be disposed over almost the entire laminated glass 10 for vehicle windows, or may be disposed over only a portion of the laminated glass 10. The peripheral portion of the curved functional film 15 and the peripheral portions of the glass plates 11 and 12 do not necessarily need to be parallel. The peripheral portion of the curved functional film 15 may overlap the shielding layer 14 in a plan view.

The planar shape of the curved function film 15 is, for example, a rectangle smaller than the planar shape of the laminated glass 10 for vehicle windows, but is not limited to a rectangle. The thickness of the curved function film 15 is, for example, 0.1 mm or more and 3 mm or less. When the laminated glass 10 for vehicle windows is applied to a windshield, the curved function film 15 is disposed in a position that does not interfere with the driver's driving.

The curved functional film 15 has a resin film. The curved functional film 15 may have a laminated structure of multiple layers, in which case it may have two or more layers of resin film. However, the curved functional film 15 is a film different from the intermediate film 13. The curved functional film 15 may include at least one of, for example, a light control film, an electric heating film, a transparent display, a film equipped with a light emitting element, and an infrared cut film. In other words, the curved functional film 15 has functional layers such as a layer having a light control function, a layer having a heat generation function, a layer having a light emitting function, and a layer that reflects/absorbs infrared rays provided on a resin film.

The light-emitting element may be, for example, an LED (Light Emitting Diode), an organic EL (Organic Electro-Luminescence), or an inorganic EL (Inorganic Electro-Luminescence). The LED here also includes a micro LED. If the curved functional film 15 is an electrically driven member, such as a light control film, an electric heating film, a transparent display, or a film equipped with light-emitting elements, a power supply member such as a bus bar or an electrode is electrically connected to the periphery of the curved functional film 15.

[Method of manufacturing laminated glass for vehicle windows]
The manufacturing method of the laminated glass 10 for vehicle windows includes a step of bending a functional film and a step of producing a laminated glass. In the step of bending a functional film, first, as shown in Fig. 3(a), curved plate-like bodies 101 and 102 that serve as molds used to mold the functional film are prepared. The curved plate-like body 101 has a main surface 101a, and the curved plate-like body 102 has a main surface 102a. Here, the curved plate-like body 101 serves as a lower mold, and the curved plate-like body 102 serves as an upper mold.

The curved plate-like bodies 101 and 102 can be formed from, for example, metals such as iron, titanium, copper, and aluminum, alloys containing these metals such as stainless steel, glasses such as soda lime glass, aluminosilicate glass, and borosilicate glass, and resins such as nylon resin and polycarbonate resin. Among these, the curved plate-like bodies 101 and 102 are preferably formed from metals that are difficult to break and have excellent durability, such as stainless steel. The curved plate-like bodies 101 and 102 may be coated with a release agent in liquid or powder form. The curved plate-like body 101 is a representative example of a first curved plate-like body according to the present invention, and the curved plate-like body 102 is a representative example of a second curved plate-like body according to the present invention.

The curved plate-like bodies 101 and 102 have a curved shape that corresponds to the final laminated glass 10 for vehicle windows. For example, if the final laminated glass 10 for vehicle windows is complex-curved, the curved plate-like bodies 101 and 102 will also have a complex-curved shape, and if the final laminated glass 10 for vehicle windows is single-curved, the curved plate-like bodies 101 and 102 will also have a single-curved shape.

However, the curved plate-like bodies 101 and 102 do not have to be entirely curved. For example, the curved plate-like bodies 101 and 102 only need to have a curved main surface facing the curved functional film 15, and the main surface opposite the curved functional film 15 does not have to correspond to the shape of the vehicle window laminated glass 10. Below, an example in which the curved plate-like bodies 101 and 102 are entirely curved is described, but this may also be applied to the main surfaces of the curved plate-like bodies 101 and 102 facing the curved functional film 15.

For example, if the radius of curvature of the final laminated glass 10 for vehicle windows is 500 mm or more and 100,000 mm or less, the radius of curvature of the curved plate-like bodies 101 and 102 is also preferably 500 mm or more and 100,000 mm or less. However, the shapes of the curved plate-like bodies 101 and 102 do not have to completely match the shape of the final laminated glass 10 for vehicle windows. For example, the minimum value of the radius of curvature of the curved plate-like body 101 may be within a range of ±50% of the minimum value of the radius of curvature of the glass plate 11, preferably within a range of ±30%, and more preferably within a range of ±20%. The minimum value of the radius of curvature of the curved plate-like body 102 may be within a range of ±50% of the minimum value of the radius of curvature of the glass plate 12, preferably within a range of ±30%, and more preferably within a range of ±20%. The same applies to the maximum values of the radii of curvature.

Even in this case, the curved functional film 15 after molding will have a shape that roughly follows the shape of the glass plates 11 and 12. Therefore, in the process of manufacturing the laminated glass 10 for vehicle windows, the curved functional film 15 deforms to a shape that follows the shape of the glass plates 11 and 12, and no visible wrinkles that exceed the allowable range are generated in the curved functional film 15. In this way, one type of curved plate-like body 101 and 102 can be used to mold functional films to be used for multiple types of glass plates 11 and 12 with different curved shapes.

Furthermore, unlike conventional solid dies, plate-shaped dies such as the curved plate-shaped bodies 101 and 102 can finely adjust the curved shape to match the curved shape of the glass plates 11 and 12. In other words, by using plate-shaped dies such as the curved plate-shaped bodies 101 and 102, which are different from conventional dies, a bending molding method for functional films that can accommodate multiple curved surface shapes can be realized.

When the radii of curvature of the curved plate-like body 101 and the curved plate-like body 102 are different, for example, the radius of curvature of the curved plate-like body 101 is smaller than the radius of curvature of the curved plate-like body 102. The plate thicknesses of the curved plate-like body 101 and the curved plate-like body 102 are almost constant, for example, about 0.3 mm to 10 mm, respectively. Almost constant means that the minimum value relative to the maximum value of the plate thickness is 0.75 or more. If the plate thickness is 0.3 mm or more, rigidity can be ensured, and if it is within 10 mm, it is easy to flexibly respond to multiple curved surface shapes. The plate thicknesses of the curved plate-like body 101 and the curved plate-like body 102 are preferably 1.1 mm or more, and more preferably 1.6 mm or more. In addition, the plate thicknesses of the curved plate-like body 101 and the curved plate-like body 102 are preferably 5 mm or less, and more preferably 3 mm or less. The thickness of curved plate body 101 and the thickness of curved plate body 102 may be the same or different.

The curved plate-like body 102 may have a through hole 102x. The through hole 102x is a through hole for supplying air to remove the curved functional film 15 from the curved plate-like bodies 101 and 102. Although the formation of the through hole 102x is not essential, forming the through hole 102x in the curved plate-like body 102 makes it easier to remove the curved functional film 15 from the curved plate-like bodies 101 and 102. The through hole for supplying air may be formed only in the curved plate-like body 101, only in the curved plate-like body 102, or both in the curved plate-like bodies 101 and 102.

The diameter of the through-hole 102x is, for example, 1 mm to 10 mm. The diameter of the through-hole 102x is preferably 3 mm or more. In addition, if the diameter of the through-hole 102x is 10 mm or less, it is preferable because the curved functional film 15 is less likely to enter the inside of the through-hole 102x, and 5 mm or less is more preferable.

The pitch of the through holes 102x is, for example, 10 mm to 200 mm. If the pitch of the through holes 102x is 10 mm or more, it is preferable because it is easier to keep the surface of the curved functional film 15 smooth, and 25 mm or more is more preferable. In addition, if the pitch of the through holes 102x is 200 mm or less, it is preferable because it has excellent releasability, and 100 mm or less is more preferable.

The diameter and pitch of the through holes 102x do not have to be uniform. For example, the pitch of the through holes 102x may be narrower as they are closer to the periphery of the curved plate-like body 102. Furthermore, the through holes 102x may be provided in only a portion of the curved plate-like body 102.

Next, the process shown in FIG. 3(b) is carried out. The process shown in FIG. 3(b) is a lamination process in which the functional film 15X is placed between the curved plate-like bodies 101 and 102 to form the laminate 100. Specifically, first, the functional film 15X is prepared. The functional film 15X is a flat functional film before being formed into the curved functional film 15. In other words, the first main surface 15a and the second main surface 15b of the functional film 15X are substantially two-dimensional flat surfaces. For example, the radius of curvature of the functional film 15X is greater than 100,000 mm.

The main surface 101a of the curved plate-like body 101 and the first main surface 15a of the functional film 15X face each other in the process of bending the functional film 15X. The main surface 102a of the curved plate-like body 102 and the second main surface 15b of the functional film 15X face each other in the process of bending the functional film 15X. The area of the main surface 101a of the curved plate-like body 101 is larger than the area of the first main surface 15a of the functional film 15X. The area of the main surface 102a of the curved plate-like body 102 is larger than the area of the second main surface 15b of the functional film 15X. In this way, since the area of the main surface of the curved plate-like body 101 is larger than the area of the main surface of the functional film 15X, pressure concentration on the peripheral portion of the functional film 15X is suppressed, and it becomes easier to apply pressure uniformly to the entire functional film 15X. As a result, it is possible to make it difficult for wrinkles to occur in the functional film 15X.

The area of the main surface 101a and the area of the main surface 102a are, for example, 0.01 ^m2 or more and 10 ^m2 or less. The area of the main surface 101a and the area of the main surface 102a may be 0.02 ^m2 or more, 0.07 ^m2 or more, or 0.1 ^m2 or more. The area of the main surface 101a and the area of the main surface 102a may be 9 ^m2 or less, or 6 ^m2 or less. The area of the main surface 101a and the area of the main surface 102a may be the same or different.

If a through hole is formed in at least one of the curved plate-like bodies 101 and 102, the through hole portion may also be included in the area of the main surface.

Next, the functional film 15X is placed between the curved plate-like bodies 101 and 102 to form the laminate 100. At this time, it is preferable to arrange the main surface 101a so that the outer periphery is outside the outer periphery of the first main surface 15a. It is also preferable to arrange the main surface 102a so that the outer periphery is outside the outer periphery of the second main surface 15b. By arranging the curved plate-like body 101, the curved plate-like body 102, and the functional film 15X in this manner, pressure concentration on the peripheral portion of the functional film 15X is suppressed, making it easier to apply pressure uniformly to the entire functional film 15X. As a result, wrinkles are less likely to occur in the functional film 15X. In addition, by suppressing pressure concentration on the peripheral portion of the functional film 15X, even if the functional film 15X has a power supply member on the peripheral portion, the power supply member is less likely to be damaged. After that, the gap between the curved plate-like body 101 and the curved plate-like body 102 is narrowed from the state shown in FIG. 3(b) so that the main surface 101a of the curved plate-like body 101 contacts the first main surface 15a of the functional film 15X and the main surface 102a of the curved plate-like body 102 contacts the second main surface 15b of the functional film 15X.

Next, the process shown in FIG. 3(c) is carried out. The process shown in FIG. 3(c) is a molding process for forming the curved functional film 15. Specifically, the functional film 15X is heated to a temperature equal to or higher than the softening point and lower than the melting point of the resin film constituting the functional film 15X. The heating method is not particularly limited, and for example, the temperature of the atmosphere (air) may be increased, or the temperatures of the curved plate-like body 101 and the curved plate-like body 102 may be increased. Then, after heating for a predetermined time, the interval between the curved plate-like body 101 and the curved plate-like body 102 is widened, and the curved functional film 15 in which the functional film 15X is hardened in a curved state is taken out. The curved functional film 15 is taken out in a state where it has been cooled to a temperature lower than the softening point of the resin film (for example, room temperature). This completes the process of bending the functional film, and the curved functional film 15 is formed. In addition, if the functional film 15X has multiple layers of resin films, it is heated to a temperature equal to or higher than the softening point of the resin film with the highest softening point among the multiple resin films, and lower than the melting point of the resin film with the lowest melting point among the multiple resin films.

After extensive research, the inventors discovered conditions under which a high-quality curved functional film 15 can be obtained even when the shapes of the curved plate-like bodies 101 and 102 do not completely match the shape of the laminated glass 10 for vehicle windows that will ultimately be manufactured.

First, the "maximum bending depth" and "depth of the arc" will be described as indicators of the curved shape. These may be applied to any of the curved plate-like body 101, the curved plate-like body 102, and the laminate 100 including them, but for example, the curved plate-like body 101 will be used for the description. The curved plate-like body 101 described here is an example in which the curved shape of the main surface 101a facing the functional film 15X is approximately the same as the curved shape of the main surface opposite the curved functional film 15. Even if the curved shapes of both main surfaces are different, the "maximum bending depth" and "depth of the arc" can be measured by, for example, creating a mold in which the curved shapes of both main surfaces are approximately the same using the main surface 101a facing the functional film 15X.

The maximum bending depth is the length of a perpendicular line drawn from the shorter line segment to the deepest point at the bottom of the curved portion when the curved plate-like body 101 is placed on a horizontal plane with the convex side facing downwards and two lines are drawn connecting the midpoints of two pairs of opposing sides, expressed in mm. The deepest point at the bottom of the curved portion may be the surface position of the concave side of the curved plate-like body 101 that corresponds to the point of contact with the horizontal plane when the curved plate-like body 101 is placed on the horizontal plane with the convex side facing downwards.

The maximum bending depth can strongly reflect the curved shape near the center of the curved functional film 15.

The depth of the arc is the length, expressed in mm, of a perpendicular line drawn from a plane parallel to the horizontal plane, which passes through the highest point of the curved plate body 101, to the deepest point at the bottom of the curved portion when the curved plate body 101 is placed on a horizontal plane with the convex side facing downwards and viewed in a direction parallel to the horizontal plane (e.g., the X-axis direction). The deepest point at the bottom of the curved portion may be the surface position of the concave side of the curved plate body 101 that corresponds to the point of contact with the horizontal plane when the curved plate body 101 is placed on the horizontal plane with the convex side facing downwards.

The depth of the arc can strongly reflect the curved shape of the peripheral portion of the curved functional film 15.

The maximum bending depth of the curved plate-like body 101 is preferably 2 mm or more, more preferably 4 mm or more, and even more preferably 6 mm or more. The maximum bending depth of the curved plate-like body 101 is preferably 60 mm or less, more preferably 50 mm or less, and even more preferably 40 mm or less.

The depth of the arc of the curved plate-like body 101 is preferably 40 mm or more, more preferably 60 mm or more, and even more preferably 80 mm or more. The depth of the arc of the curved plate-like body 101 is preferably 250 mm or less, more preferably 200 mm or less, and even more preferably 180 mm or less.

In addition, the maximum bending depth and the arc depth can also be used as indicators of the curved shape of the laminated glass for vehicle windows 10 by replacing the curved plate-like body 101 with the glass sheet 11, the glass sheet 12, or the laminated glass for vehicle windows 10 in the above definition. The maximum bending depth and the arc depth of the curved plate-like body 101 may be the same as the maximum bending depth and the arc depth of the glass sheet 11, respectively.

Furthermore, the inventors have found that even if the shape of the curved plate-like bodies 101 and 102 does not completely match the shape of the final laminated glass for vehicle windows 10, i.e., even if the maximum bending depth and arc depth of the curved plate-like body 101 are different from the maximum bending depth and arc depth of the glass sheet 11, respectively, a high-quality laminated glass for vehicle windows 10 can be obtained if formula (1) is satisfied in the lamination process or the forming process.

ここで、
Ｌ_１は、ガラス板１２の対向する辺の中点同士を、第１方向に面に沿って結んだ長さ［ｍｍ］、
Ｌ_２は、ガラス板１２の対向する辺の中点同士を、第２方向に面に沿って結んだ長さ［ｍｍ］、
Ｗは、湾曲板状体１０１の最大曲げ深さ［ｍｍ］、
Ｗ'は、ガラス板１１の最大曲げ深さ［ｍｍ］、
Ａは、湾曲板状体１０１の弧の深さ［ｍｍ］、
Ａ'は、ガラス板１１の弧の深さ［ｍｍ］、
である。

Where:
_L1 is the length [mm] between the midpoints of the opposing sides of the glass plate 12 along the surface in the first direction,
_L2 is the length [mm] between the midpoints of the opposing sides of the glass plate 12 along the surface in the second direction,
W is the maximum bending depth of the curved plate-like body 101 [mm],
W' is the maximum bending depth of the glass sheet 11 [mm],
A is the arc depth of the curved plate-like body 101 [mm],
A' is the arc depth of the glass plate 11 [mm],
It is.

The value of the left side of formula (1) is preferably 180 or more, and more preferably 250 or more.

After the lamination process shown in FIG. 3(b), a decompression process in which the laminate 100 is held at a gauge pressure of -70 kPa or less, or a pressurization process in which the laminate 100 is held at an absolute pressure of 0.6 MPa or more may be added. These processes may be performed before the preliminary pressure bonding process described later. By adding one or both of these processes, the functional film 15X can be made to conform to the shape of the glass plates 11 and 12. When both of these processes are added, the order of the decompression process and the pressurization process is preferable. In addition, the pressurization process in which the laminate 100 is held at an absolute pressure of 0.6 MPa or more also has the effect of suppressing the occurrence of orange peel. Here, orange peel is a phenomenon in which fine irregularities that do not exceed the thickness of the curved functional film 15 are formed on the curved functional film 15, causing the outline of the reflected image to appear fluctuating. However, if the curved functional film 15 meets the required specifications without adding these processes, these processes do not need to be added.

In FIG. 3(b), the curved plate-like bodies 101 and 102 are used so that the upper side is convex, but this is not limited thereto, and the curved plate-like bodies 101 and 102 may be used so that the lower side is convex.

Next, the laminated glass 10 for vehicle windows is produced by the process shown in FIG. 4(a) and FIG. 4(b). First, glass sheets 11 and 12 are prepared as shown in FIG. 4(a). Glass sheets 11 and 12 are bent into a desired shape that is predetermined by design drawings, CAD data, or the like. For example, the gravity forming method can be used to bend glass sheets 11 and 12, in which the glass sheets are placed on a ring mold and passed through a heating furnace, heated and softened, and bent into the desired shape by gravity. Alternatively, a press forming method can be used in which the glass sheets are sandwiched between a male mold and a female mold and pressurized to form the glass sheets.

If necessary, a shielding layer 14 may be formed on the glass plate 11 and/or the glass plate 12. In this embodiment, the case where the shielding layer 14 is formed on the glass plate 12 is illustrated. The shielding layer 14 can be formed, for example, by applying a ceramic color paste containing a fusible glass frit containing a black pigment onto the glass plate by screen printing or the like, and then firing the paste, but is not limited to this. The shielding layer 14 can also be formed, for example, by applying an organic ink containing a black or dark color pigment onto the glass plate by screen printing or the like, and then drying the paste.

Next, the preliminary pressure-bonding step shown in FIG. 4(b) is carried out. In the preliminary pressure-bonding step, the first intermediate film 131, the curved functional film 15 obtained in the step shown in FIG. 3(c), and the second intermediate film 132 are sequentially arranged between the glass plate 11 and the glass plate 12 to form a laminate 120, and the laminate 120 is pressure-bonded. For example, the laminate 120 is placed in a rubber bag, a rubber channel, a resin bag, or the like, and pressure-bonded at a temperature controlled to a range of about 70°C to 120°C in a vacuum controlled to a gauge pressure of -100 kPa to -65 kPa. Alternatively, the laminate 120 may be passed between nipper rolls to apply a pressure equivalent to this to the laminate 120. Heating conditions, temperature conditions, and lamination methods are appropriately selected.

After the preliminary pressure bonding process shown in FIG. 4(b), the main pressure bonding process is carried out. In the main pressure bonding process, for example, a pressure bonding process is carried out by heating and pressing under controlled conditions of an absolute pressure of 0.6 MPa to 1.3 MPa and a temperature of 100°C to 150°C. This results in a laminated glass 10 for vehicle windows with excellent durability. In some cases, the main pressure bonding process may not be carried out in consideration of the simplification of the process and the characteristics of the material to be filled in the laminated glass 10 for vehicle windows. In other words, the main pressure bonding process is carried out as necessary.

Here, glass plate 11, glass plate 12, and intermediate film 13 will be described in detail.

[Glass plate]
The glass plates 11 and 12 may be inorganic glass or organic glass. As the inorganic glass, for example, soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, etc. are used without any particular limitation. The glass plate 12 located on the outer side of the laminated glass for vehicle windows 10 is preferably inorganic glass from the viewpoint of scratch resistance, and is preferably soda-lime glass from the viewpoint of formability. When the glass plates 11 and 12 are soda-lime glass, clear glass, green glass containing a predetermined amount or more of iron components, and UV-cut green glass can be suitably used.

The inorganic glass may be either untempered glass or tempered glass. Untempered glass is made by forming molten glass into a plate shape and slowly cooling it. Tempered glass is made by forming a compressive stress layer on the surface of untempered glass.

The tempered glass may be either physically tempered glass, such as air-cooled tempered glass, or chemically tempered glass. In the case of physically tempered glass, the glass surface can be tempered by generating a compressive stress layer on the glass surface due to the temperature difference between the glass surface and the interior of the glass through an operation other than slow cooling, such as rapidly cooling a glass sheet that has been uniformly heated during bending from a temperature near its softening point.

In the case of chemically strengthened glass, for example, after bending, the glass surface can be strengthened by generating compressive stress on the glass surface by ion exchange or the like. Glass that absorbs ultraviolet or infrared rays may also be used, and although transparent glass is preferable, a glass plate that is colored to the extent that transparency is not impaired may also be used.

On the other hand, examples of materials for organic glass include transparent resins such as polycarbonate, acrylic resins such as polymethyl methacrylate, polyvinyl chloride, and polystyrene.

The shape of the glass plates 11 and 12 is not particularly limited to a rectangular shape, and may be processed into various shapes and curvatures. In addition to the gravity forming method and press forming method described above, roller forming method and the like may be used to bend the glass plates 11 and 12. There are also no particular limitations on the forming method of the glass plates 11 and 12, but for example, in the case of inorganic glass, glass plates formed by a float method or the like are preferred.

The thickness of the glass plate 12 is preferably 1.1 mm or more and 3 mm or less at the thinnest part. If the thickness of the glass plate 12 is 1.1 mm or more, the strength such as resistance to flying stones is sufficient, and if the thickness is 3 mm or less, the mass of the laminated glass for vehicle windows 10 does not become too large, which is preferable in terms of fuel efficiency of the vehicle. The thickness of the glass plate 12 is more preferably 1.8 mm or more and 2.8 mm or less at the thinnest part, more preferably 1.8 mm or more and 2.6 mm or less, even more preferably 1.8 mm or more and 2.2 mm or less, and even more preferably 1.8 mm or more and 2.0 mm or less.

The thickness of the glass plate 11 is preferably 0.3 mm or more and 2.3 mm or less. If the thickness of the glass plate 11 is 0.3 mm or more, it is easy to handle, and if it is 2.3 mm or less, the mass is not too large.

Furthermore, if the thickness of glass sheet 11 is not appropriate, forming two sheets of glass with particularly deep curves as glass sheets 11 and 12 will result in a mismatch in the shapes of the two sheets, which will have a significant impact on the glass quality, such as residual stress after bonding.

However, by making the thickness of the glass plate 11 0.3 mm or more and 2.3 mm or less, it is possible to maintain the glass quality, such as residual stress. Making the thickness of the glass plate 11 0.3 mm or more and 2.3 mm or less is particularly effective in maintaining the glass quality of glass with a deep curvature. The thickness of the glass plate 11 is more preferably 0.5 mm or more and 2.1 mm or less, and even more preferably 0.7 mm or more and 1.9 mm or less. Within this range, the above-mentioned effects become even more pronounced.

When the laminated glass 10 for vehicle windows is used, for example, in a head-up display (HUD), the glass sheets 11 and/or 12 may not have a constant thickness, but may have a thickness that varies from place to place as necessary. For example, when the laminated glass 10 for vehicle windows is a windshield, one or both of the glass sheets 11 and 12 may have a wedge-shaped cross section whose thickness gradually increases from the bottom edge to the top edge of the windshield when the windshield is attached to the vehicle. In this case, as long as the thickness of the intermediate film 13 is constant, the total wedge angle of the glass sheets 11 and 12 may be changed, for example, in a range of more than 0 mrad to 1.0 mrad or less.

A coating having water repellency and ultraviolet and infrared blocking properties, or a coating having low reflectance and low radiation properties may be provided on the outside of the glass plates 11 and/or 12. In addition, a coating having ultraviolet and infrared blocking properties, low radiation properties, visible light absorption properties, coloring properties, etc. may be provided on the side of the glass plates 11 and/or 12 that contacts the intermediate film 13.

When the glass sheets 11 and 12 are curved inorganic glass, the glass sheets 11 and 12 are bent after being shaped by a float method or the like and before being bonded with the interlayer film 13. The bending is performed by softening the glass by heating. The heating temperature of the glass during bending is preferably controlled in the range of approximately 550°C to 700°C.

[Interlayer]
Thermoplastic resins are often used for the intermediate film 13, and examples of such thermoplastic resins include those conventionally used for this type of application, such as plasticized polyvinyl acetal resins, plasticized polyvinyl chloride resins, saturated polyester resins, plasticized saturated polyester resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, cycloolefin polymer resins, ionomer resins, etc. Also suitable for use is a resin composition containing a modified hydrogenated block copolymer described in Japanese Patent No. 6065221.

Among these, plasticized polyvinyl acetal resins are preferably used because they have an excellent balance of properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. These thermoplastic resins may be used alone or in combination of two or more types. In the above plasticized polyvinyl acetal resins, "plasticized" means that the resin has been plasticized by adding a plasticizer. The same applies to other plasticized resins.

However, when a specific object is enclosed in the intermediate film 13, the object may be deteriorated by a specific plasticizer depending on the type of object, and in such a case, it is preferable to use a resin that does not substantially contain the plasticizer. Examples of resins that do not contain plasticizers include ethylene-vinyl acetate copolymer (EVA) resins.

Examples of the polyvinyl acetal resin include polyvinyl formal resin obtained by reacting polyvinyl alcohol (PVA) with formaldehyde, polyvinyl acetal resin in the narrow sense obtained by reacting PVA with acetaldehyde, and polyvinyl butyral (PVB) resin obtained by reacting PVA with n-butylaldehyde. PVB is particularly preferred because it has an excellent balance of various properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. These polyvinyl acetal resins may be used alone or in combination of two or more types.

However, the material forming the intermediate film 13 is not limited to thermoplastic resin. The intermediate film 13 may also contain functional particles such as infrared absorbers, ultraviolet absorbers, and luminescent agents. The intermediate film 13 may also have a colored portion called a shade band. The color pigment used to form the colored portion is one that can be used for plastics, and the amount added may be adjusted so that the visible light transmittance of the colored portion is 40% or less. For example, organic color pigments such as azo, phthalocyanine, quinacridone, perylene, perinone, dioxazine, anthraquinone, and isoindolino, and inorganic color pigments such as oxides, hydroxides, sulfides, chromates, sulfates, carbonates, silicates, phosphates, arsenates, ferrocyanides, carbon, and metal powders may be used. These color pigments may be used alone or in combination of two or more types.

The thickness of the intermediate film 13 is preferably 0.5 mm or more at the thinnest part. When the intermediate film 13 is composed of the first intermediate film 131 and the second intermediate film 132, the thickness of the intermediate film 13 is the sum of the thickness of the first intermediate film 131 and the thickness of the second intermediate film 132. If the thickness of the thinnest part of the intermediate film 13 is 0.5 mm or more, the impact resistance required for laminated glass for vehicle windows is sufficient. In addition, the thickness of the intermediate film 13 is preferably 3 mm or less at the thickest part. If the maximum thickness of the intermediate film 13 is 3 mm or less, the mass of the laminated glass for vehicle windows does not become too large. The maximum thickness of the intermediate film 13 is more preferably 2.8 mm or less, and even more preferably 2.6 mm or less.

When the laminated glass 10 for vehicle windows is used, for example, as a HUD, the intermediate film 13 does not have to have a constant thickness, and the thickness may vary from place to place as necessary. For example, when the laminated glass 10 for vehicle windows is a windshield, the intermediate film 13 may have a wedge-shaped cross section whose thickness gradually increases from the bottom edge to the top edge of the windshield when the windshield is attached to the vehicle. In this case, if the thickness of the glass sheets 11 and 12 is constant, the wedge angle of the intermediate film 13 may be changed, for example, in a range greater than 0 mrad and less than or equal to 1.0 mrad.

The intermediate film 13 may have three or more layers. For example, if the intermediate film is formed of three or more layers and the shear modulus of any layer other than the layers on both sides is made smaller than the shear modulus of the layers on both sides by adjusting the plasticizer or the like, the sound insulation of the laminated glass for vehicle windows 10 can be improved. In this case, the shear modulus of the layers on both sides may be the same or different.

In addition, the first intermediate film 131 and the second intermediate film 132 included in the intermediate film 13 are preferably formed of the same material, but may be formed of different materials. However, from the viewpoint of adhesion to the glass plates 11 and 12, or the functional materials to be inserted into the laminated glass for vehicle windows 10, it is preferable that the above-mentioned materials be used for 50% or more of the film thickness of the intermediate film 13.

To produce the interlayer film 13, for example, the above-mentioned resin material that will become the interlayer film is appropriately selected and extruded in a heated and molten state using an extruder. The extrusion conditions, such as the extrusion speed of the extruder, are set so as to be uniform. The extruded resin film is then stretched as necessary, for example, to give the upper and lower edges a curvature in accordance with the design of the laminated glass for vehicle windows, thereby completing the interlayer film 13.

[Laminated glass for vehicle windows]
The total thickness of the laminated glass for vehicle windows 10 is preferably 2.8 mm or more and 10 mm or less. If the total thickness of the laminated glass for vehicle windows 10 is 2.8 mm or more, sufficient rigidity can be ensured. If the total thickness of the laminated glass for vehicle windows 10 is 10 mm or less, sufficient transmittance can be obtained and haze can be reduced.

On at least one side of the laminated glass 10 for vehicle windows, the plate misalignment between the glass plates 11 and 12 is preferably 1.5 mm or less, and more preferably 1 mm or less. Here, the plate misalignment between the glass plates 11 and 12 refers to the amount of misalignment between the outer peripheral side surface of the glass plate 11 and the outer peripheral side surface of the glass plate 12 in a plan view.

At least one side of the laminated glass 10 for vehicle windows, if the misalignment between the glass sheets 11 and 12 is 1.5 mm or less, this is preferable in terms of not impairing the appearance. At least one side of the laminated glass 10 for vehicle windows, if the misalignment between the glass sheets 11 and 12 is 1.0 mm or less, this is even more preferable in terms of not impairing the appearance.

Examples and Comparative Examples
Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. Examples 1 and 2 are Examples, and Example 3 is a Comparative Example.

[Example 1]
In Example 1, a laminated glass LG1 for evaluation having the same structure as the laminated glass 10 for vehicle windows was produced. First, the functional film 15X was pre-bent to produce a curved functional film 15. Specifically, curved plate-shaped bodies 101 and 102 made of soda lime glass and having a complex curved shape were prepared, and a light control film was placed between the curved plate-shaped bodies 101 and 102 as the functional film 15X, and a laminate A was formed in which the curved plate-shaped body 101, the functional film 15X, and the curved plate-shaped body 102 were laminated. The dimensions of the curved plate-shaped body 101 were 1400 mm long x 1100 mm wide x 1.8 mm thick. The dimensions of the curved plate-shaped body 102 were 1400 mm long x 1100 mm wide x 2.0 mm thick. All of the vertical and horizontal dimensions were measured along the main surface. In addition, the light control film had a PET film on the surface, and an electrode was electrically connected to the peripheral portion. The dimensions of the light-control film before bending, excluding the electrodes, were 1100 mm long x 800 mm wide x 120 μm thick. The maximum bending depth of the laminate A was 40 mm, and the arc depth was 120 mm.

Next, the laminate A was placed in a resin bag and placed in a vacuum device, the pressure in the vacuum device was reduced to a gauge pressure of -70 kPa or less, and the resin bag was held at room temperature for 5 to 10 minutes to create a vacuum. The laminate A in the resin bag was then removed from the vacuum device, and placed in an oven with the laminate A still in the resin bag, and the oven was set to atmospheric pressure and a temperature of 130°C and held for 30 minutes or more. The temperature was then returned to room temperature, and the laminate A was removed from the resin bag. Further, force was applied to the laminate A to separate the curved plate-like bodies 101 and 102, and the functional film 15X was removed. A curved functional film 15 curved roughly along the shape of the curved plate-like bodies 101 and 102 was completed. Note that 130°C is a temperature above the softening point and below the melting point of the PET film of the functional film 15X.

Next, the curved functional film 15 taken out of the resin bag was used to prepare the evaluation laminated glass LG1. Specifically, a complex curved glass plate 11 that would become the inner plate (glass plate on the inside of the vehicle) when the laminated glass was made, a complex curved glass plate 12 that would become the outer plate (glass plate on the outside of the vehicle), a first intermediate film 131, and a second intermediate film 132 were prepared. The dimensions of the glass plate 11 were 1400 mm long x 1100 mm wide x 1.8 mm thick. The dimensions of the glass plate 12 were 1400 mm long x 1100 mm wide x 2 mm thick. The dimensions of the first intermediate film 131 and the second intermediate film 132 were both 1400 mm long x 1100 mm wide x 0.4 mm thick. EVA was used for the first intermediate film 131 and the second intermediate film 132.

Then, the glass plate 11, the glass plate 12, the first intermediate film 131, and the second intermediate film 132 were laminated together with the bending function film 15 in the order shown in FIG. 4(b) to produce a laminate B. Next, the laminate B was placed in a rubber bag and bonded at a temperature of about 70°C to 120°C in a vacuum with a gauge pressure of -100 kPa to -65 kPa to produce an evaluation laminated glass LG1. In the evaluation laminated glass LG1 produced, the minimum radius of curvature was 905 mm, the maximum bending depth was 40 mm, and the arc depth was 120 mm.

[Example 2]
In Example 2, an evaluation laminated glass LG2 having the same structure as the laminated glass 10 for vehicle windows was produced. First, the functional film 15X was pre-bent. Specifically, curved plate-shaped bodies 101 and 102 made of glass were prepared, and a light control film was placed between the curved plate-shaped bodies 101 and 102 as the functional film 15X, and a laminate C in which the curved plate-shaped body 101, the functional film 15X, and the curved plate-shaped body 102 were laminated was formed. The curved plate-shaped bodies 101 and 102 and the functional film 15X used were the same as those in Example 1. The maximum bending depth of the laminate C was 40 mm, and the arc depth was 120 mm.

Next, the laminate C was placed in a resin bag and placed in a vacuum device, the pressure in the vacuum device was reduced to a gauge pressure of -70 kPa or less, and the pressure was maintained at room temperature for 5 to 10 minutes to create a vacuum in the resin bag. The laminate C in the resin bag was then removed from the vacuum device, and the laminate C was supported in a predetermined manner while still in the resin bag and placed in an autoclave, where it was maintained at an absolute pressure of 1.27 MPa and a temperature of 135°C for 20 minutes. The temperature was then returned to room temperature, and the laminate C was removed from the resin bag, and the functional film 15X was removed from the curved plate-like bodies 101 and 102. A curved functional film 15 curved roughly along the shape of the curved plate-like bodies 101 and 102 was completed. Note that 135°C is a temperature above the softening point and below the melting point of the PET film of the functional film 15X.

Next, PVB measuring 1400 mm long x 1100 mm wide x 0.38 mm thick was used as the first interlayer film 131, and PVB measuring 1400 mm long x 1100 mm wide x 0.76 mm thick was used as the second interlayer film 132. The glass plate 11, the glass plate 12, the first interlayer film 131, and the second interlayer film 132 were laminated together with the curved functional film 15 in the order shown in FIG. 4(b) to produce laminate B. Next, laminate B was placed in a rubber bag and bonded at a temperature of about 70°C to 120°C in a vacuum with a gauge pressure of -100 kPa to -65 kPa. Then, pressure and heat were applied under conditions of an absolute pressure of 0.6 MPa to 1.3 MPa and a temperature of about 100°C to 150°C to produce laminated glass LG2 for evaluation. The evaluation laminated glass LG2 produced had a minimum radius of curvature of 905 mm, a maximum bending depth of 40 mm, and an arc depth of 120 mm.

[Example 3]
Except for not performing pre-bending of the functional film 15X, a laminated glass for evaluation LG3 was produced in the same manner as in Example 2. In the produced laminated glass for evaluation LG3, the minimum radius of curvature was 905 mm, the maximum bending depth was 40 mm, and the arc depth was 120 mm.

[Evaluation of Examples 1 to 3]
Next, the laminated glasses LG1 to LG3 for evaluation produced in Examples 1 to 3 were evaluated for the occurrence of wrinkles and orange peel in the curved functional film 15, and a comprehensive evaluation was made based on the results.

＜Wrinkles＞
The laminated glass for evaluation was visually observed for the presence or absence of wrinkles in the functional film at the peripheral portion along the entire outer periphery, and was evaluated according to the following criteria.
A: No visible wrinkles were observed in the functional film within 20 mm from the entire outer periphery of the laminated glass for evaluation (within the acceptable range).
C: Visible wrinkles were observed in at least a part of the functional film within 20 mm from the entire outer periphery of the laminated glass for evaluation (outside the acceptable range).
<Orange Peel>
The laminated glass for evaluation prepared in a dark background was placed on a horizontal plane, and a straight-tube fluorescent lamp (length 630 mm, 30 W, FL30SW manufactured by Mitsubishi Electric Lighting Co., Ltd.) was placed 180 cm above the laminated glass for evaluation so that the length direction was the width direction of the laminated glass for evaluation and turned on. The position of the fluorescent lamp was adjusted so that it was directly above the center of the laminated glass for evaluation, and the presence or absence of fluctuation in the outline of the reflected image of the fluorescent lamp in the center was visually observed. Similarly, the position of the fluorescent lamp was adjusted so that it was directly above the vicinity of the lower side of the laminated glass for evaluation, and the presence or absence of fluctuation in the outline of the reflected image of the fluorescent lamp in the vicinity of the lower side was visually observed. The observation results were evaluated according to the following criteria.
A: No fluctuation is observed in the outline of the fluorescent light reflection image.
C: Fluctuation is observed in at least a part of the outline of the fluorescent light reflection image.

It is preferable that orange peel does not occur, but it is acceptable for laminated glass even if it does occur. In other words, if the evaluation result for wrinkles is A, the overall evaluation for laminated glass is A even if the evaluation result for orange peel is C. On the other hand, if the evaluation result for wrinkles is C, the overall evaluation for laminated glass is C, regardless of the evaluation result for orange peel.

例１～例３の評価結果を機能フィルム１５Ｘの予備曲げの条件と共に表１にまとめた。表１に示す通り、例３のように機能フィルム１５Ｘの予備曲げを行わないと、機能フィルム１５Ｘの外周から７０ｍｍ以上にわたり許容できないしわが生じ、合わせガラスとしての総合評価はＣとなった。これに対して、例１及び例２のように機能フィルム１５Ｘの予備曲げを行って湾曲機能フィルム１５を作製することで、しわは許容範囲となり、合わせガラスとしての総合評価はＡ以上となった。具体的には、例１及び例２では湾曲機能フィルム１５にしわが生じたが、例１のしわの位置は外周から２０ｍｍ以内であり、例２のしわの位置は、外周から１０ｍｍ以内であった。特に、機能フィルム１５Ｘの予備曲げの工程が、例２のように積層体を絶対圧力０．６ＭＰａ以上で保持する加圧工程を含む場合は、オレンジピールがなくなり、合わせガラスとしての総合評価はＡＡとなった。

The evaluation results of Examples 1 to 3 are summarized in Table 1 together with the conditions for pre-bending the functional film 15X. As shown in Table 1, when the functional film 15X was not pre-bended as in Example 3, unacceptable wrinkles were generated over 70 mm or more from the outer periphery of the functional film 15X, and the overall evaluation as a laminated glass was C. In contrast, when the functional film 15X was pre-bended to produce a curved functional film 15 as in Examples 1 and 2, the wrinkles were within the acceptable range, and the overall evaluation as a laminated glass was A or higher. Specifically, wrinkles were generated in the curved functional film 15 in Examples 1 and 2, but the wrinkles in Example 1 were located within 20 mm from the outer periphery, and the wrinkles in Example 2 were located within 10 mm from the outer periphery. In particular, when the pre-bending process of the functional film 15X included a pressurizing process in which the laminate was held at an absolute pressure of 0.6 MPa or more as in Example 2, orange peel disappeared, and the overall evaluation as a laminated glass was AA.

As described above, if the functional film is not pre-bent, wrinkles will occur due to stresses that occur in the functional film as it conforms to the curved shape of the glass sheet during the laminated glass manufacturing process. In contrast, by pre-bending the functional film to produce a curved functional film, the stresses that occur in the curved functional film before the laminated glass manufacturing process are alleviated, making it less likely to develop wrinkles even after the laminated glass manufacturing process.

Although the preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

REFERENCE SIGNS LIST 10 Laminated glass for vehicle windows 11, 12 Glass plate 13 Interlayer film 131 First interlayer film 132 Second interlayer film 14 Shielding layer 15 Curved functional film 15X Functional film 101, 102 Curved plate-like body 100, 120 Laminate

Claims (17)

A method for producing a laminated glass for a vehicle window in which first and second glass sheets are bonded together via an interlayer film, comprising the steps of:
a lamination step of disposing a functional film including a resin film between the first and second curved plate-like bodies to form a laminate;
a molding step of heating the functional film to a temperature equal to or higher than the softening point and lower than the melting point of the resin film to form a curved functional film;
A first pressure-bonding step of disposing and pressure-bonding the intermediate film and the bending function film between the first and second glass plates,
an area of a main surface of the first curved plate-like body is larger than an area of a first main surface of the functional film that faces the main surface of the first curved plate-like body;
A method for manufacturing laminated glass for vehicle windows, wherein an area of a main surface of the second curved plate-like body is larger than an area of a second main surface of the functional film that faces the main surface of the second curved plate-like body. The method for manufacturing laminated glass for vehicle windows according to claim 1, wherein the first pressure bonding step is performed at a gauge pressure of -100 kPa or more and -65 kPa or less and at a temperature of 70°C or more and 120°C or less. The method for manufacturing laminated glass for vehicle windows according to claim 1 or 2, wherein the first and second curved plate-like bodies have a complex curved main surface facing the functional film. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 3, wherein the minimum value of the radius of curvature of the first and second curved plate-like bodies is 500 mm or more and 100,000 mm or less. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 4, further comprising a decompression step of maintaining the laminate at a gauge pressure of -70 kPa or less after the lamination step. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 5, further comprising a pressurizing step of holding the laminate at an absolute pressure of 0.6 MPa or more after the lamination step. The method for producing a laminated glass for a vehicle window according to any one of claims 1 to 6, wherein the areas of the main surfaces of the first and second curved plate-like bodies are 0.01 ^m2 or more and 10 ^m2 or less. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 7, wherein the first or second curved plate-like body has a through hole. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 8, wherein the functional film includes at least one of a light control film, an electric heating film, a transparent display, a film equipped with a light emitting element, and an infrared cut film. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 9, wherein a power supply member is electrically connected to the peripheral portion of the functional film. The manufacturing method of laminated glass for vehicle windows according to any one of claims 1 to 10, wherein the lamination process includes a process of arranging the first curved plate-like body so that the outer periphery of the main surface of the first curved plate-like body and the outer periphery of the main surface of the second curved plate-like body are outside the outer periphery of the first main surface of the functional film and the outer periphery of the second main surface of the functional film, respectively. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 11, further comprising a second crimping step in which the first crimping step is followed by crimping at an absolute pressure of 0.6 MPa to 1.3 MPa and a temperature of 100°C to 150°C. The minimum value of the radius of curvature of the first curved plate-like body is within a range of ±50% of the minimum value of the radius of curvature of the first glass plate,
13. The method for manufacturing a laminated glass for a vehicle window according to claim 1, wherein a minimum value of a radius of curvature of the second curved plate-like body is in a range of ±50% of a minimum value of a radius of curvature of the second glass plate. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 13, wherein the maximum bending depth of the first curved plate-like body is 2 mm or more and 60 mm or less. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 14, wherein the arc depth of the first curved plate-like body is 40 mm or more and 250 mm or less. The method for manufacturing laminated glass for vehicle windows according to any one of claims 1 to 15, wherein the maximum bending depth and arc depth of the first curved plate-like body are equal to the maximum bending depth and arc depth of the first glass plate, respectively. The maximum bending depth and the arc depth of the first curved plate-like body are different from the maximum bending depth and the arc depth of the first glass sheet, respectively;
The method for producing a laminated glass for a vehicle window according to claim 1 , which satisfies the following formula (1):

Where:
In a plan view of the first glass plate, of two line segments connecting midpoints of two pairs of opposing sides, a direction of a shorter line segment is defined as a first direction and a direction of a longer line segment is defined as a second direction;
_L1 is the length [mm] between the midpoints of the opposing sides of the first glass plate along the surface in the first direction;
_L2 is the length [mm] between the midpoints of the opposing sides of the first glass plate along the surface in the second direction;
W is the maximum bending depth of the first curved plate-like body [mm],
W' is the maximum bending depth of the first glass sheet [mm],
A is the arc depth of the first curved plate-like body [mm],
A' is the arc depth of the first glass sheet [mm],
It is.

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