Manufacturing method for laminated glass for vehicle windows

Abstract

To provide a method for manufacturing a laminated glass for a vehicle window which facilitates a design of a joint condition of a laminate and prevents occurrence of wrinkles in a functional film.SOLUTION: A method for manufacturing a laminated glass for a vehicle window in which first and second glass plates whose main surfaces have curved surfaces are bonded to each other through an intermediate film includes a first lamination step of arranging a functional film including a resin film between first and second molds having curved shapes, and forming a first laminate, a molding step of heating the functional film at a first temperature T1, and forming a curved functional film, a second lamination step of arranging the intermediate film and the curved functional film between the first and second glass plates, and forming a second laminate, and a first pressure-bonding step of pressure-bonding the second laminate at a second temperature T2 at which the second laminate is heated and pressure-bonded, and when a highest temperature in a step following the molding step is represented by Tmax, the first temperature T1 is higher than the highest temperature Tmax.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for producing laminated glass for vehicle windows. [Background technology]

[0002] In recent years, a technique for encapsulating a functional film such as a light control film in laminated glass used in vehicles and the like has become known (see, for example, Patent Document 1 and Patent Document 2). The laminated glass of Patent Document 1 has a first glass plate, a first interlayer film, a light control film, a second interlayer film, and a second glass plate laminated in this order. In this laminated glass, the first glass plate and the second glass plate are formed into a three-dimensional curved surface.

[0003] When manufacturing laminated glass having a functional film between such curved glass plates, wrinkles are likely to occur, for example, at the periphery of the functional film, etc. Patent Document 1 discloses a method in which a liquid crystal film is heated to a temperature equal to or higher than the glass transition point of a substrate layer of the liquid crystal film to form the three-dimensional curved surface shape of the laminated glass, and then the laminate in which the liquid crystal film is sandwiched between two glass plates is heated at a temperature below the glass transition point of the substrate layer and pressed at a predetermined pressure to bond them. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 088261 [Patent Document 2] International Publication No. 2014 / 122704 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, laminated glass is often manufactured through a preliminary pressure bonding step in which the laminate is held at a temperature in the range of about 70°C to 120°C, and a main pressure bonding step in which the laminate is further held at a temperature in the range of about 100°C to 150°C in some cases. For example, in Patent Document 2, the laminate is pre-pressed at 110°C using a vacuum bag, and then pressurized and heated at 135°C using an autoclave. If the temperature of these steps is changed, various problems such as poor degassing, poor adhesion, foaming, and glass cracking may occur, so the various conditions must be carefully redesigned. On the other hand, when the laminate is heated at a temperature below the glass transition point of the substrate layer and pressed at a predetermined pressure to be bonded, the substrate layer usable as a functional film is limited to, for example, a type having a relatively high glass transition point.

[0006] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a method for producing laminated glass for vehicle windows in which the bonding conditions of the laminate can be easily designed and wrinkles are less likely to occur in the functional film. [Means for solving the problem]

[0007] A method for producing a laminated glass for a vehicle window according to one embodiment of the present disclosure is a method for producing a laminated glass for a vehicle window in which first and second glass plates, each having a curved main surface, are bonded together via an interlayer film, The intermediate film is a thermoplastic resin, The method includes a first lamination step of arranging a functional film including a resin film between first and second molds having a curved shape to form a first laminate, a molding step of heating the functional film to a first temperature T1 to form a curved functional film, a second lamination step of arranging an intermediate film and a curved functional film between first and second glass plates to form a second laminate, and a first compression step of heating and compressing the second laminate at a second temperature T2, and the maximum temperature in the step after the molding step is T max Then, the first temperature T1 is the maximum temperature T max Higher. Effect of the Invention

[0008] According to one embodiment of the disclosure, it is possible to provide a method for producing laminated glass for vehicle windows, which allows easy design of bonding conditions for a laminate and reduces the occurrence of wrinkles in a functional film. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a laminated glass for vehicle windows according to an embodiment of the present invention. [Diagram 2] 1 is a perspective view illustrating a laminated glass for a vehicle window according to an embodiment of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating a method for bending a functional film. [Figure 4] FIG. 2 is a diagram illustrating a method for producing a laminated glass for a vehicle window according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiment of the present invention will be described with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicated explanations may be omitted. In each drawing, the size and shape may be partially exaggerated to make the contents of the present invention easier to understand.

[0011] The vehicle is typically an automobile, but also refers to any moving body having laminated glass for vehicle windows, including trains, ships, aircraft, etc.

[0012] In addition, the term "planar view" refers to a specified area of ​​the laminated glass for vehicle windows viewed from the normal direction of the surface facing the exterior side of the laminated glass for vehicle windows, and the term "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 facing the exterior side of the laminated glass for vehicle windows.

[0013] [Laminated glass for vehicle windows] Fig. 1 is a diagram illustrating a laminated glass for a vehicle window according to the present embodiment, and Fig. 1(a) is a schematic diagram of the laminated glass for a vehicle window in a plan view. Fig. 1(b) is a cross-sectional view taken along line AA in Fig. 1(a). Fig. 2 is a perspective view illustrating the laminated glass for a vehicle window according to the present embodiment.

[0014] As shown in Fig. 1 and Fig. 2, the laminated glass for vehicle windows 10 includes 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.

[0015] Here, in a plan view of the laminated glass for vehicle windows 10, of the two line segments connecting the midpoints of two pairs of opposing sides, the direction of the shorter line segment is defined as the first direction, and the direction of the longer line segment is defined as 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 AA) is the second direction. In the example shown in FIG. 1(a), the first direction and the second direction are perpendicular to each other. When the lengths of the two line segments connecting the midpoints of the opposing sides are the same, either one may be defined as 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 defined as the first direction, and the other may be defined as the second direction.

[0016] 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 any one direction. The curved shape may include a single curved shape and a complex curved shape. A surface of a curved shape is also called a curved surface.

[0017] The laminated glass for vehicle windows 10 is preferably curved so as to be convex toward the vehicle exterior (second side). In Fig. 1(a), the laminated glass for vehicle windows 10 is rectangular in plan view, but the laminated glass for vehicle windows 10 is not limited to a rectangular shape and may be any shape including a trapezoidal shape.

[0018] The laminated glass 10 for vehicle windows can be used, for example, as a front glass, rear glass, roof glass, front side glass, rear side glass, front bench glass, rear quarter glass, extra window, etc. of a vehicle.

[0019] The glass plate 11 is an interior glass plate that becomes the interior side (first side) of the vehicle when the laminated glass for vehicle windows 10 is installed in a vehicle. The glass plate 12 is an exterior glass plate that becomes the exterior side (second side) of the vehicle when the laminated glass for vehicle windows 10 is installed in a vehicle. The glass plate 11 is a typical example of the first glass plate according to the present invention, and the glass plate 12 is a typical example of the second glass plate according to the present invention.

[0020] 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.

[0021] The glass plate 11 and the glass plate 12 are a pair of glass plates facing each other, and the intermediate film 13 and the bending function film 15 are located between the pair of glass plates. The glass plate 11 and the glass plate 12 are fixed together with the intermediate film 13 and the bending function film 15 sandwiched therebetween.

[0022] The interlayer film 13 is a film that bonds the glass plate 11 and the glass plate 12. The interlayer film 13 has, for example, a first interlayer film 131 that bonds to the glass plate 11 and a second interlayer film 132 that bonds to the glass plate 12. In addition to the first interlayer film 131 and the second interlayer film 132, a frame-shaped interlayer film that is located between the first interlayer film 131 and the second interlayer 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 interlayer film 131 and the second interlayer film 132, they are simply referred to as the interlayer film 13.

[0023] In addition, the outermost contour portion of the object in a plan view is referred to as the periphery, and the area having a width including the periphery is referred to as the peripheral portion. Also, the surface including the periphery and connecting one main surface of the object to the other main surface is referred to as the outer periphery side surface.

[0024] The outer peripheral side surface of the interlayer 13 is preferably edge-treated. In other words, the outer peripheral side surface of the interlayer 13 is preferably treated so as not to protrude significantly from the outer peripheral side surfaces of the glass sheets 11 and 12. If the amount of protrusion of the outer peripheral side surface of the interlayer 13 from the outer peripheral side surfaces of the glass sheets 11 and 12 is 150 μm or less, this 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 sheet 11, the glass sheet 12, and the interlayer 13 will be described later.

[0025] 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 of any color, but is preferably a dark color such as black, brown, gray, or dark blue, or white, and more preferably black. The shielding layer 14 may be a colored intermediate film or colored film having light-shielding properties, a combination of a colored intermediate film and a colored ceramic layer, or a layer having a light-adjusting function. The colored film may be integrated with an infrared reflective film, etc.

[0026] 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 suppress deterioration of an 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, caused by 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.

[0027] 1 and 2, the shielding layer 14 is provided on the peripheral portion of the vehicle interior surface of the glass plate 12. However, the shielding layer 14 may be provided on the peripheral portion of the vehicle interior surface of the glass plate 11, or on both the peripheral portion of the vehicle interior surface of the glass plate 11 and the peripheral portion of the vehicle interior surface of the glass plate 12, as necessary. Alternatively, the shielding layer 14 need not be provided.

[0028] 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 is formed and 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 on almost the entire laminated glass 10 for vehicle windows, or may be disposed on only a part of it. 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 with the shielding layer 14 in a plan view.

[0029] 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 at a position that does not interfere with the driver's driving.

[0030] 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, an infrared cut film, a radio wave control film, a polarizing film, and a visible light scattering film. That is, the curved functional film 15 has a functional layer such as a layer having a light control function, a layer having a heat generation function, a layer having a light emitting function, a layer that reflects / absorbs infrared rays, and a layer that selectively transmits / reflects / absorbs radio waves of a predetermined wavelength on a resin film. Alternatively, the curved functional film 15 may be a resin film in which the entirety of a polarizing film, a visible light scattering film, etc. acts as a functional layer.

[0031] The resin film preferably contains at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate, polyamide, polyether, polysulfone, polyethersulfone, polycarbonate, polystyrene, cyclic polyolefin, polyarylate, polyetherimide, polyetheretherketone, polyimide, aramid, polybutylene terephthalate, triacetyl cellulose, polyurethane, and cycloolefin polymer. The resin film more preferably contains at least one selected from the group consisting of polyethylene terephthalate (PET), cycloolefin polymer, polycarbonate, and polystyrene.

[0032] The glass transition temperature Tg of the resin film may be, for example, 50° C. to 180° C. The glass transition temperature Tg of the resin film may be 55° C. or higher, 60° C. or higher, 65° C. or higher, or 70° C. or higher. The glass transition temperature Tg of the resin film may be 150° C. or lower, 120° C. or lower, 90° C. or lower, or 80° C. or lower.

[0033] 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. The transparent display is a transparent member that includes a plurality of light-emitting elements and is capable of displaying images. The light control film is a film that can switch the visible light transmittance, haze, etc., between a plurality of states. The switching mechanism is not particularly limited, and for example, oriented particles or liquid crystals can be used.

[0034] In addition, when the curved functional film 15 is an electrically driven component, for example, a light control film, an electric heating film, a transparent display, or a film equipped with a light emitting element, a power supply component such as a bus bar or an electrode is electrically connected to the peripheral portion of the curved functional film 15.

[0035] A radio wave control film is a layer that selectively transmits, reflects, or absorbs radio waves of a specific wavelength. The specific wavelength is, for example, a wavelength of 1 mm or more. Radio waves of a specific wavelength include, for example, at least one of submillimeter waves, millimeter waves, microwaves, ultra-high frequency waves, ultra-high frequency waves, short waves, and medium waves.

[0036] [Method of manufacturing laminated glass for vehicle windows] The manufacturing method of the laminated glass 10 for vehicle windows will be described with reference to FIG. 3. The manufacturing method includes a forming step of curving the functional film and a step of producing laminated glass. The forming step of curving the functional film is also called a pre-bending step. In the manufacturing process of the laminated glass 10 for vehicle windows, the first temperature T1 in the pre-bending step is higher than the maximum temperature T2 in the step after the pre-bending step (when heating the second laminate, which will be described later). max This makes it easy to design the bonding conditions for the laminate and provides a laminated glass for vehicle windows in which wrinkles are less likely to occur in the functional film. max More details will be provided later.

[0037] In the preliminary bending process, first, as shown in Fig. 3(a), forming dies 101 and 102 to be used for forming the functional film are prepared. Forming die 101 has a main surface 101a, and forming die 102 has a main surface 102a. Here, forming die 101 serves as the lower die, and forming die 102 serves as the upper die.

[0038] The molds 101 and 102 can be made of, 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 molds 101 and 102 are preferably made of metals that are difficult to break and have excellent durability, such as stainless steel. The molds 101 and 102 may be coated with a release agent in liquid or powder form. The mold 101 is a representative example of a first mold according to the present invention, and the mold 102 is a representative example of a second mold according to the present invention.

[0039] The forming dies 101 and 102 have a curved shape corresponding to the final laminated glass 10 for a vehicle window. For example, if the final laminated glass 10 for a vehicle window has a complex curved shape, the forming dies 101 and 102 also have a complex curved shape, and if the final laminated glass 10 for a vehicle window has a single curved shape, the forming dies 101 and 102 also have a single curved shape. The curved shape of the forming dies 101 and 102 is preferably approximately the same as the curved shape of the curved surfaces of the glass sheets 11 and 12.

[0040] However, the forming dies 101 and 102 do not have to be entirely curved. For example, the forming dies 101 and 102 only need to have a curved shape (curved surface) as the main surface facing the curved function film 15, and the main surface opposite the curved function film 15 does not have to correspond to the shape of the laminated glass 10 for vehicle windows. Below, an example in which the forming dies 101 and 102 are entirely curved will be described, but this may also be applied to the main surface of the forming dies 101 and 102 facing the curved function film 15.

[0041] For example, if the radius of curvature of the laminated glass 10 for vehicle windows that is finally produced is 500 mm or more and 100,000 mm or less, the radius of curvature of the shaping molds 101 and 102 is also preferably 500 mm or more and 100,000 mm or less. However, the shapes of the shaping molds 101 and 102 do not have to completely match the shape of the laminated glass 10 for vehicle windows that is finally produced. For example, the minimum value of the radius of curvature of the shaping mold 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 shaping mold 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.

[0042] Even in this case, the curved functional film 15 after forming has a shape that roughly follows the shape of the glass plates 11 and 12. Therefore, in the process of producing the laminated glass 10 for vehicle windows, the curved functional film 15 deforms into a shape that follows the shape of the glass plates 11 and 12, and no visible wrinkles beyond the allowable range are generated in the curved functional film 15. In this way, one type of forming mold 101 and 102 can be used to form functional films to be used for a plurality of types of glass plates 11 and 12 having different curved shapes.

[0043] Furthermore, if the forming dies 101 and 102 are plate-shaped dies as shown in Fig. 3(a), the curved shape can be finely adjusted to match the curved shapes of the glass plates 11 and 12, and a bending forming method for functional films that can accommodate a variety of curved surface shapes can be realized. However, the forming dies 101 and 102 do not necessarily have to be plate-shaped. For example, at least one of the forming dies 101 and 102 may be a non-plate-shaped solid die.

[0044] When the radii of curvature of the mold 101 and the mold 102 are different, for example, the radius of curvature of the mold 101 is smaller than the radius of curvature of the mold 102. When the mold 101 and the mold 102 are plate-shaped, each may be, for example, about 0.3 mm to 10 mm. When the mold 101 and the mold 102 are plate-shaped, each plate thickness is preferably almost constant. Almost constant means that the minimum value of the plate thickness is 0.75 or more relative to the maximum value. 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 thickness of the mold 101 and the mold 102 is preferably 1.1 mm or more, more preferably 1.6 mm or more. Furthermore, the plate thickness of the mold 101 and the mold 102 is preferably 5 mm or less, more preferably 3 mm or less. The plate thickness of the mold 101 and the mold 102 may be the same or different.

[0045] The molding die 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 molding dies 101 and 102. Although the formation of the through hole 102x is not essential, by forming the through hole 102x in the molding die 102, it becomes easier to remove the curved functional film 15 from the molding dies 101 and 102. The through hole for supplying air may be formed only in the molding die 101, may be formed only in the molding die 102, or may be formed in both the molding dies 101 and 102.

[0046] 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. Moreover, if the diameter of the through-hole 102x is 10 mm or less, it is preferable because the bending function film 15 is unlikely to enter the inside of the through-hole 102x, and the diameter of the through-hole 102x is more preferably 5 mm or less.

[0047] 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 the surface of the curved functional film 15 can be easily kept smooth, and more preferably 25 mm or more. In addition, if the pitch of the through holes 102x is 200 mm or less, it is preferable because excellent releasability can be obtained, and more preferably 100 mm or less.

[0048] 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 it approaches the periphery of the molding die 102. Furthermore, the through-holes 102x may be provided in only a part of the molding die 102.

[0049] Next, the step shown in FIG. 3(b) is carried out. The step shown in FIG. 3(b) is a lamination step in which a functional film 15X is disposed between the molds 101 and 102 to form a laminate 100 (first laminate). This lamination step is also called a first lamination step. Specifically, first, a functional film 15X is prepared. The functional film 15X is a flat functional film before being formed into a curved functional film 15. That is, 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. It is preferable that the molds 101 and 102 are larger than the functional film 15X in a planar view.

[0050] The main surface 101a of the mold 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 mold 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 mold 101 may be equal to or larger than the area of ​​the first main surface 15a of the functional film 15X, but is preferably larger than the area of ​​the first main surface 15a of the functional film 15X. The area of ​​the main surface 102a of the mold 102 may be equal to or larger than the area of ​​the second main surface 15b of the functional film 15X, but is preferably larger than the area of ​​the second main surface 15b of the functional film 15X. In this way, the area of ​​the main surface of the molding die 101 is larger than the area of ​​the main surface of the functional film 15X, which prevents pressure from concentrating on the peripheral edge of the functional film 15X and makes 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.

[0051] The area of ​​the main surface 101a and the area of ​​the main surface 102a are each, for example, 0.01 m 2More than 10m 2 The area of ​​the main surface 101a and the area of ​​the main surface 102a are each 0.02 m 2 More than 0.07m is fine. 2 More than 0.1m is fine. 2 The area of ​​the main surface 101a and the area of ​​the main surface 102a may be 9 m or more. 2 Less than 6m is fine. 2 The area of ​​the main surface 101a and the area of ​​the main surface 102a may be the same or different.

[0052] When a through hole is formed in at least one of the forming dies 101 and 102, the area of ​​the through hole may also be included in the area of ​​the main surface.

[0053] Next, the functional film 15X is placed between the molds 101 and 102 to form the laminate 100 (first laminate). At this time, it is preferable to place 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 place the main surface 102a so that the outer periphery is outside the outer periphery of the second main surface 15b. By placing the molds 101, 102, and the functional film 15X in this manner, 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, 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. Then, the distance between molding die 101 and molding die 102 is narrowed from the state shown in Figure 3(b) so that main surface 101a of molding die 101 contacts first main surface 15a of functional film 15X and main surface 102a of molding die 102 contacts second main surface 15b of functional film 15X.

[0054] Next, the process shown in FIG. 3(c) is carried out. The process shown in FIG. 3(c) is a forming process for forming the curved functional film 15. Specifically, the functional film 15X (shown in FIG. 3(b)) is heated to a first temperature T1. The first temperature T1 is preferably higher than the glass transition temperature Tg of the resin film constituting the functional film 15X. The first temperature T1 may be 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 mold 101 and the mold 102 may be increased. Then, after heating for a predetermined time, the distance between the mold 101 and the mold 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 is cooled to a temperature lower than the transition temperature Tg of the resin film (for example, room temperature). The above completes the forming process (pre-bending process) for bending the functional film, and the curved functional film 15 is formed. In addition, when the functional film 15X has multiple layers of resin films, it is sufficient to heat it to a temperature that is equal to or higher than the glass transition temperature Tg of the resin film with the highest glass transition temperature Tg 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.

[0055] The first temperature T1 may be, for example, higher than 60° C., higher than 80° C., higher than 100° C., higher than 120° C., higher than 140° C., higher than 160° C., or higher than 180° C. The first temperature T1 may be, for example, 250° C. or lower, or 200° C. or lower.

[0056] Here, the "bending depth" will be described as an index representing the curved shape. This may be applied to any of the mold 101, the mold 102, and the laminate 100 including them, but for example, the mold 101 will be used for the description. The mold 101 described here is an example in which the curved shape of the main surface 101a facing the functional film 15X and the curved shape of the main surface opposite the curved functional film 15 are substantially identical. The curved shapes being substantially identical means that the minimum value of the curvature radius of one curved shape may be within a range of ±50% of the minimum value of the curvature radius of the other curved shape, preferably within a range of ±30%, and more preferably within a range of ±20%. The same applies to the maximum value of the curvature radius. Note that even if the curved shapes of both main surfaces are different, the "maximum bending depth" can be measured by, for example, producing a mold in which the curved shapes of both main surfaces are substantially identical using the main surface 101a facing the functional film 15X.

[0057] The bending depth is the length of a perpendicular line drawn from one of the two lines to the deepest point at the bottom of the curved portion when the forming die 101 is placed on a horizontal plane with the convex side facing downward and two lines are drawn connecting the midpoints of two pairs of opposing sides, and is expressed in mm. The larger of the two bending depths is the maximum bending depth. The deepest point at the bottom of the curved portion may be the surface position of the concave side of the forming die 101 that corresponds to the contact point with the horizontal plane when the forming die 101 is placed on the horizontal plane with the convex side facing downward.

[0058] The maximum bending depth of the molding die 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 molding die 101 is preferably 60 mm or less, more preferably 50 mm or less, and even more preferably 40 mm or less.

[0059] In the above definition, the bending depth can also be used as an index representing the curved shape of the laminated glass for vehicle windows 10 by replacing the forming mold 101 with the glass sheet 11, the glass sheet 12, or the laminated glass for vehicle windows 10. The bending depth of the forming mold 101 may be the same as the bending depth of the glass sheet 11.

[0060] In addition, after the first lamination step shown in FIG. 3(b), a depressurization step of holding the laminate 100 at a gauge pressure of −70 kPa or less, or a pressurization step of holding the laminate 100 at an absolute pressure of 0.6 MPa or more may be added. These steps may be performed before the preliminary pressure bonding step described later. By adding one or both of these steps, the functional film 15X can be made to conform to the shape of the glass plates 11 and 12. When both of these steps are added, the order of the depressurization step and the pressurization step is preferable. In addition, the pressurization step of holding the laminate 100 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.

[0061] In FIG. 3(b), the forming dies 101 and 102 are used so that the upper side is convex, but the present invention is not limited to this, and the forming dies 101 and 102 may be used so that the lower side is convex.

[0062] Next, a laminated glass 10 for vehicle windows is produced by the steps shown in FIG. 4(a) and FIG. 4(b). First, glass sheets 11 and 12 are prepared as shown in FIG. 4(a). The glass sheets 11 and 12 are bent into a desired shape determined in advance by design drawings, CAD data, or the like. Therefore, the main surfaces of the glass sheets 11 and 12 have curved surfaces. For bending the glass sheets 11 and 12, for example, a gravity forming method can be used in which the glass sheets are placed on a ring mold and passed through a heating furnace, heated and softened, and bent into a 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 pressed to form.

[0063] If necessary, a shielding layer 14 may be formed on the glass plate 11 and / or the glass plate 12. In the present embodiment, a 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 thereto. The shielding layer 14 may also be formed, for example, by applying an organic ink containing a black or dark color pigment or a white pigment onto the glass plate by screen printing or the like, and then drying the paste.

[0064] Next, a preliminary pressure-bonding step shown in Fig. 4(b) is performed. In the preliminary pressure-bonding step, first, a second lamination step is performed in which a first intermediate film 131, a curved functional film 15 obtained in the step shown in Fig. 3(c), and a second intermediate film 132 are sequentially arranged between the glass plate 11 and the glass plate 12 to form a laminate 120 (second laminate). Next, this laminate 120 (second laminate) is heated and pressure-bonded. For example, this laminate 120 is placed in a rubber bag or a resin bag, or a rubber channel is attached to the periphery, and pressure-bonded by controlling the temperature in the range of about 70°C to 120°C in a vacuum controlled at a gauge pressure of -100 kPa to -65 kPa.

[0065] When the compression temperature of the second laminate in the preliminary compression bonding process is the second temperature T2, the second temperature T2 is lower than the first temperature T1 in the molding process for forming the curved functional film described above. In general, both elements of plastic deformation and elastic deformation occur above the glass transition temperature Tg and below the melting point of the resin, and the higher the temperature, the greater the proportion of plastic deformation. Therefore, the force acting on the curved functional film in the preliminary compression bonding process to return to its original shape is less likely to cause plastic deformation, and the curved shape of the curved functional film is more likely to be maintained in the preliminary compression bonding process. Therefore, by making the second temperature T2 lower than the first temperature T1, wrinkles are less likely to occur in the curved functional film. It is also possible to apply a pressure equivalent to the above-mentioned pressure to the laminate 120 by passing the laminate 120 between nipper rolls without using a vacuum. In this case, the laminate is also heated at the second temperature T2 lower than the first temperature T1.

[0066] The second temperature T2 may be higher than the glass transition temperature Tg of the resin film. Therefore, it is not necessary to adjust the second temperature T2 in consideration of the Tg of the resin film. The second temperature T2 may be 75°C or higher, 80°C or higher, 85°C or higher, or 90°C or higher. In addition, the second temperature T2 may be 115°C or lower, 110°C or lower, 105°C or lower, or 100°C or lower.

[0067] After the preliminary step shown in FIG. 4(b), the main pressure bonding step is performed. Here, for the purpose of explaining the case where the main pressure bonding step is performed, the laminate after pressure bonding by the preliminary pressure bonding step shown in FIG. 4(b) is also referred to as the laminate 120 (second laminate). In the main pressure bonding step, the laminate 120 (second laminate) is subjected to a pressure bonding treatment in which it is heated and pressed under conditions controlled, for example, in the range of an absolute pressure of 0.6 MPa to 1.3 MPa and a temperature of 100° C. to 150° C. As a result, a laminated glass 10 for vehicle windows having excellent durability is obtained. In some cases, the main pressure bonding step may not be performed in consideration of 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 step is performed as necessary.

[0068] When the bonding temperature of the laminate in the main bonding step is the third temperature T3, the third temperature T3 may be equal to or higher than the second temperature T2 and lower than the first temperature T1. Alternatively, the third temperature T3 may be lower than the second temperature T2. Therefore, the curved shape of the curved functional film is easily maintained in the main bonding step, and wrinkles are less likely to occur in the curved functional film. The third temperature T3 can also be said to be the heating temperature of the curved functional film 15.

[0069] The third temperature T3 may also be higher than the glass transition temperature Tg of the resin film. Therefore, it is not necessary to adjust the third temperature T3 in consideration of the Tg of the resin film. The third temperature T3 may be 105°C or higher, 110°C or higher, 115°C or higher, or 120°C or higher. In addition, the third temperature T3 may be 145°C or lower, 140°C or lower, 135°C or lower, or 130°C or lower.

[0070] As described above, the manufacturing method of the laminated glass 10 for vehicle windows according to one embodiment includes, after the preliminary bending step, a first pressure-bonding step of performing pressure-bonding at a second temperature T2 and a second pressure-bonding step of performing pressure-bonding at a third temperature T3 as steps of heating and pressing the second laminate. That is, the manufacturing method includes, after the first pressure-bonding step, a second pressure-bonding step of performing pressure-bonding at an absolute pressure of 0.6 MPa or more and 1.3 MPa or less and at a third temperature T3. The second temperature T2 and the third temperature T3 are both lower than the first temperature T1. That is, the first temperature T1 is equal to or lower than the maximum temperature T max Therefore, in the process after the preliminary bending process, the bending function film 15 is unlikely to be subjected to a plastic deformation force greater than that in the preliminary bending process, and the bending function film 15 is likely to maintain its curved shape. In other words, wrinkles are unlikely to occur in the bending function film 15. In addition, when the first temperature T1 is set to the maximum temperature T max By setting it higher, it becomes easier to design the bonding conditions for the laminate in the steps subsequent to the pre-bending step.

[0071] The first temperature T1 and the maximum temperature T max The difference is preferably 2° C. or more, more preferably 5° C. or more, more preferably 10° C. or more, and even more preferably 15° C. or more. The upper limit of the difference is not particularly limited, and may be, for example, 90° C., 70° C., 50° C., or 30° C.

[0072] In addition, as a process subsequent to the preliminary bending process, for example, the process of heating and pressing the second laminate may be only one (for example, the first pressing process), may be only two (for example, the first pressing process and the second pressing process), or may be three or more. In these cases, the maximum temperature T max may be a second temperature T2, a third temperature T3, or a fourth temperature equal to or higher than the second temperature T2 and the third temperature T3, as long as the second temperature T2 is lower than the first temperature T1.

[0073] Here, the glass plate 11, the glass plate 12, and the interlayer film 13 will be described in detail.

[0074] [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. can be 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.

[0075] The inorganic glass may be either unstrengthened glass or tempered glass. Unstrengthened glass is obtained by forming molten glass into a plate shape and slowly cooling it. Tempered glass is obtained by forming a compressive stress layer on the surface of unstrengthened glass.

[0076] 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 inside of the glass by an operation other than slow cooling, such as rapidly cooling a glass sheet uniformly heated in bending from a temperature near the softening point.

[0077] In the case of chemically strengthened glass, for example, after bending, the glass surface can be strengthened by generating a compressive stress on the glass surface by an ion exchange method or the like. Glass that absorbs ultraviolet or infrared rays may also be used. Furthermore, although transparent glass is preferable, a glass plate that is colored to the extent that transparency is not impaired may also be used.

[0078] 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.

[0079] 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, a roller forming method or the like may be used for bending the glass plates 11 and 12. The forming method of the glass plates 11 and 12 is also not particularly limited, but for example, in the case of inorganic glass, glass plates formed by a float method or the like are preferable.

[0080] The thickness of the glass plate 12 is preferably 1.1 mm or more and 3 mm or less at the thinnest part. When the thickness of the glass plate 12 is 1.1 mm or more, the strength such as resistance to flying stones is sufficient, and when 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, further preferably 1.8 mm or more and 2.6 mm or less, further preferably 1.8 mm or more and 2.2 mm or less, and further preferably 1.8 mm or more and 2.0 mm or less.

[0081] 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, the glass plate 11 is easy to handle, and if the thickness is 2.3 mm or less, the weight does not become too large.

[0082] Furthermore, if the thickness of the glass plate 11 is not appropriate, when two pieces of glass with particularly deep curves are formed as the glass plates 11 and 12, a mismatch will occur between the shapes of the two pieces, which will have a significant impact on the glass quality, such as residual stress after compression bonding.

[0083] However, by setting the thickness of the glass plate 11 to 0.3 mm or more and 2.3 mm or less, the glass quality such as residual stress can be maintained. Setting the thickness of the glass plate 11 to 0.3 mm or more and 2.3 mm or less is particularly effective in maintaining the glass quality of deeply curved glass. The thickness of the glass plate 11 is more preferably 0.5 mm or more and 2.1 mm or less, and further preferably 0.7 mm or more and 1.9 mm or less. Within this range, the above-mentioned effects become more remarkable.

[0084] When the laminated glass for vehicle windows 10 is used in, for example, 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 for vehicle windows 10 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 lower edge to the upper edge of the windshield when the windshield is attached to a vehicle. In this case, as long as the thickness of the interlayer film 13 is constant, the total wedge angle of the glass sheets 11 and 12 may be changed, for example, in the range of more than 0 mrad to 1.0 mrad or less.

[0085] A coating having water repellency and ultraviolet and infrared blocking properties, or a coating having low reflection and low radiation properties may be provided on the outer side 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 interlayer film 13.

[0086] When the glass sheets 11 and 12 are curved inorganic glass, the glass sheets 11 and 12 are bent after being formed 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 about 550°C to 700°C.

[0087] [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, as described in Japanese Patent No. 6065221.

[0088] Among these, plasticized polyvinyl acetal resins are preferably used because they have 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 thermoplastic resins may be used alone or in combination of two or more. The term "plasticized" in the plasticized polyvinyl acetal resin means that it is plasticized by adding a plasticizer. The same applies to other plasticized resins.

[0089] 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 that 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.

[0090] 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, and the like. In particular, PVB is 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 kinds.

[0091] However, the material forming the intermediate film 13 is not limited to thermoplastic resin. The intermediate film 13 may contain functional particles such as infrared absorbing agents, ultraviolet absorbing agents, and luminescent agents. The intermediate film 13 may 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-based, phthalocyanine-based, quinacridone-based, perylene-based, perinone-based, dioxazine-based, anthraquinone-based, and isoindolino-based pigments, 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.

[0092] The thickness of the interlayer film 13 is preferably 0.5 mm or more at the thinnest part. When the interlayer film 13 is composed of the first interlayer film 131 and the second interlayer film 132, the thickness of the interlayer film 13 is the sum of the thickness of the first interlayer film 131 and the thickness of the second interlayer film 132. When the thickness of the thinnest part of the interlayer film 13 is 0.5 mm or more, the impact resistance required for a laminated glass for a vehicle window is sufficient. In addition, the thickness of the interlayer film 13 is preferably 3 mm or less at the thickest part. When the maximum thickness of the interlayer film 13 is 3 mm or less, the mass of the laminated glass for a vehicle window does not become too large. The maximum thickness of the interlayer film 13 is more preferably 2.8 mm or less, and even more preferably 2.6 mm or less.

[0093] When the laminated glass 10 for vehicle windows is used as, for example, a HUD, the interlayer film 13 does not 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 interlayer film 13 may have a wedge-shaped cross section whose thickness gradually increases from the lower edge to the upper edge of the windshield when the windshield is attached to the vehicle. In this case, as long as the thicknesses of the glass sheets 11 and 12 are constant, the wedge angle of the interlayer film 13 may be changed, for example, in the range of more than 0 mrad to 1.0 mrad or less.

[0094] The interlayer film 13 may have three or more layers. For example, when the interlayer 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.

[0095] Furthermore, the first interlayer film 131 and the second interlayer film 132 included in the interlayer 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 functional materials to be incorporated into the laminated glass 10 for vehicle windows, it is desirable that 50% or more of the thickness of the interlayer film 13 be made of the above-mentioned materials.

[0096] 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 to be uniform. Thereafter, the extruded resin film is stretched as necessary to give curvature to the upper and lower sides in accordance with the design of the laminated glass for vehicle windows, thereby completing the interlayer film 13.

[0097] [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. Also, 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.

[0098] The plate misalignment between the glass plates 11 and 12 is preferably 1.5 mm or less, and more preferably 1 mm or less, on at least one side of the laminated glass for vehicle windows 10. 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.

[0099] It is preferable that the misalignment between the glass plates 11 and 12 is 1.5 mm or less on at least one side of the laminated glass for vehicle windows 10, since the appearance is not impaired. It is even more preferable that the misalignment between the glass plates 11 and 12 is 1.0 mm or less on at least one side of the laminated glass for vehicle windows 10, since the appearance is not impaired.

[0100] Examples and Comparative Examples Examples and comparative examples will be described below, but the present invention is not limited to these examples in any way. Examples 1 and 2 are examples, and Examples 3 to 5 are comparative examples.

[0101] [Example 1] In Example 1, a laminated glass LG1 for evaluation was produced, which had the same structure as the laminated glass 10 for vehicle windows. First, a curved functional film 15 was produced by pre-bending a functional film 15X. Specifically, complex-curved molds 101 and 102 made of soda lime glass were prepared. Then, as a first lamination step, a light control film was placed between the molds 101 and 102 as the functional film 15X, and a laminate A (first laminate) was formed in which the mold 101, the functional film 15X, and the mold 102 were laminated. The dimensions of the molds 101 and 102 were 300 mm long x 300 mm wide x 2.0 mm thick. The vertical and horizontal dimensions were measured along the main surfaces. In addition, the light control film was provided with a transparent conductive layer and a liquid crystal layer having a light control function between two PET films having a glass transition temperature Tg of about 90°C and a thickness of 50 μm. The dimensions of the light-control film before bending were 250 mm length × 250 mm width × 120 μm thickness.

[0102] 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 evacuated by holding at room temperature for 5 to 10 minutes. After that, the laminate A in the resin bag was removed from the vacuum device, and the laminate A was placed in an oven while still in the resin bag as a molding process, and the pressure in the oven was set to atmospheric pressure and the temperature was about 150°C (T1 = 150°C), and the oven was held for 30 minutes or more. After that, the laminate A was returned to room temperature and removed from the resin bag, and further force was applied to the laminate A to separate the molds 101 and 102, and the functional film 15X (curved functional film 15) was removed. A curved functional film 15 curved roughly along the shape of the molds 101 and 102 was completed.

[0103] Next, the curved functional film 15 taken out of the resin bag was used to prepare a laminated glass LG1 for evaluation. Specifically, a complex curved glass plate 11 that would become an inner plate (glass plate on the inside of the vehicle) when the laminated glass was prepared, a complex curved glass plate 12 that would become an 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 and the glass plate 12 were 300 mm long x 300 mm wide x 2.0 mm thick. The bending depths of the glass plate 11 and the glass plate 12 were both 7.5 mm in the shallow direction and 17.5 mm in the deep direction. The dimensions of the first intermediate film 131 were 300 mm long x 300 mm wide x 0.38 mm thick, and the dimensions of the second intermediate film 132 were 300 mm long x 300 mm wide x 0.76 mm thick. PVB was used for the first intermediate film 131 and the second intermediate film 132.

[0104] Then, in the second lamination step, 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 a laminate B (second laminate). Next, a rubber channel was attached to the periphery of the laminate B. Then, in the first pressure bonding step, the laminate B was placed in an oven while keeping the gauge pressure in the rubber channel at -100 kPa or more and -65 kPa or less with a vacuum pump, and was held at a temperature of about 110°C (T2 = 110°C) for about 40 minutes to bond the laminate B. Next, in the second pressure bonding step, the laminate B was pressurized and heated for 20 minutes or more under conditions of an absolute pressure of 0.6 MPa or more and 1.3 MPa or less and a temperature of about 135°C (T3 = 135°C) to produce a laminated glass LG1 for evaluation. That is, the maximum temperature T in the step after the molding step was max The temperature T3 was 135°C.

[0105] [Example 2] In Example 2, a laminated glass LG2 for evaluation was produced, which had the same structure as the laminated glass 10 for vehicle windows. First, a curved functional film 15 curved approximately along the shape of the forming molds 101 and 102 was obtained in the same manner as in Example 1, except that the temperature inside the oven was set to about 120°C (T1 = 120°C) in the forming process.

[0106] Next, EVA having a length of 300 mm, a width of 300 mm, and a thickness of 0.40 mm was used as the first interlayer 131 and the second interlayer 132. Then, in the second lamination step, the glass plate 11, the glass plate 12, the first interlayer 131, and the second interlayer 132 were laminated together with the curved functional film 15 in the order shown in FIG. 4(b) to produce a laminate C (a second laminate). Next, a rubber channel was attached to the periphery of the laminate C. Then, in the first pressure bonding step, the laminate C was placed in an oven while keeping the gauge pressure in the rubber channel at -100 kPa or more and -65 kPa or less with a vacuum pump, and was held at a temperature of about 110°C (T2=110°C) for about 40 minutes to bond the laminate C, and an evaluation laminated glass LG2 was produced. It should be noted that Example 2 does not include the second pressure bonding step. That is, the maximum temperature T max The temperature T2 was 110°C.

[0107] [Example 3] In Example 3, a laminated glass for evaluation LG3 was produced having the same structure as the laminated glass for vehicle windows 10. The laminated glass for evaluation LG3 was produced in the same manner as in Example 1, except that the temperature inside the oven was set to about 120°C (T1 = 120°C) in the molding process.

[0108] [Example 4] In Example 4, a laminated glass for evaluation LG4 was produced having the same structure as the laminated glass for vehicle windows 10. First, as in Example 1, in the first lamination step, a laminate A was formed in which the forming mold 101, the functional film 15X, and the forming mold 102 were laminated.

[0109] 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 evacuated by holding at room temperature for 5 to 10 minutes. After that, the laminate A in the resin bag was removed from the vacuum device, and as a molding process, the laminate A was supported in a predetermined manner while still in the resin bag and placed in an autoclave, and pressurized and heated at an absolute pressure of 0.6 MPa to 1.3 MPa and a temperature of 135°C (T1 = 135°C) for 20 minutes or more. After that, the laminate A was returned to room temperature and removed from the resin bag, and the functional film 15X was removed from the molding dies 101 and 102. A curved functional film 15 curved approximately along the shape of the molding dies 101 and 102 was completed.

[0110] Next, the bending function film 15 taken out from the resin bag was used to prepare a laminated glass LG4 for evaluation in the same manner as in Example 1. In this case, the same glass plate 11, glass plate 12, first interlayer film 131, and second interlayer film 132 as in Example 1 were used.

[0111] [Example 5] In Example 5, a laminated glass for evaluation LG5 having the same structure as the laminated glass for vehicle windows 10 was produced. In Example 5, the preliminary bending step was not performed, and the laminated glass for evaluation LG5 was produced in the same manner as in Example 1. That is, the functional film 15X was used without being formed into a curved functional film 15.

[0112] [Evaluation of Examples 1 to 5] Next, the laminated glasses for evaluation LG1 to LG5 produced in Examples 1 to 5 were evaluated for the presence or absence of wrinkles in the bending functional film 15, and a comprehensive evaluation was made based on the results.

[0113] <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 on the functional film of the evaluation laminated glass. (Within the acceptable range) C: Visible wrinkles were observed in at least a part of the functional film of the evaluation laminated glass (outside the acceptable range). [Table 1] The evaluation results of Examples 1 to 5 are summarized in Table 1, along with the conditions for pre-bending functional film 15X. When pre-bending of functional film 15X was not performed as in Example 5 in Table 1, visible wrinkles of approximately 10 mm were generated from each side of the outer periphery of functional film 15X toward the inside of functional film 15X, and the wrinkle evaluation was C. In addition, as in Examples 3 and 4, under the condition that the preliminary bending temperature was equal to or lower than the pressure bonding temperature, visible wrinkles of about 3 mm in Example 3 and about 2.5 mm in Example 4 were generated from each side of the outer periphery of the curved functional film 15 toward the inside of the curved functional film 15, and the wrinkles were evaluated as C. In Examples 3 and 4, the generation of visible wrinkles was not observed in the curved functional film 15 after the preliminary pressure bonding and before the main pressure bonding. In contrast, as in Examples 1 and 2, by pre-bending the functional film 15X under conditions where the pre-bending temperature is higher than the pressure bonding temperature to produce the curved functional film 15, the wrinkles are within the allowable range, and the wrinkle evaluation is A. In Example 1, no visible wrinkles were observed in the curved functional film 15 after the pre-bending and before the main pressure bonding.

[0114] In this way, if the functional film is not pre-bent under the specified conditions, wrinkles will occur due to stress generated in the functional film when the functional film follows the curved shape of the glass sheet during the manufacturing process of the laminated glass. In contrast, by pre-bending the functional film under specified conditions to produce a curved functional film, the stress generated in the curved functional film is alleviated before the manufacturing process of the laminated glass, so that wrinkles are less likely to occur even after the manufacturing process of the laminated glass.

[0115] Although the preferred embodiments have been described in detail above, 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. [Explanation of symbols]

[0116] 10. Laminated glass for vehicle windows 11, 12 Glass plate 13 Interlayer 131 First intermediate film 132 Second intermediate film 14 Shielding layer 15 Curved functional film 15X Functional Film 101, 102 mold 100, 120 laminate

Claims

1. A method for producing a laminated glass for a vehicle window, in which first and second glass plates each having a curved main surface are bonded together via an interlayer film, comprising the steps of: The intermediate film is a thermoplastic resin, a first lamination step of disposing a functional film including a resin film between first and second molding dies having a curved shape to form a first laminate; The functional film is heated to a first temperature T １ a forming step of forming a curved functional film by heating the film to a desired temperature; a second lamination step of disposing the intermediate film and the bending function film between the first and second glass plates to form a second laminate; A second temperature T at which the second laminate is heated and pressed ２ A first crimping step of crimping The maximum temperature in the process after the molding process is T ｍａｘ When the first temperature T １ is the maximum temperature T ｍａｘ Higher, The method for producing a laminated glass for a vehicle window, wherein the second temperature T 2 is higher than a glass transition temperature Tg of the resin film.

2. The first temperature T １ and the maximum temperature T ｍａｘ The method for producing a laminated glass for vehicle windows according to claim 1 , wherein the difference between the temperature and the temperature is 2° C. or more.

3. The first temperature T １ The method for producing a laminated glass for a vehicle window according to claim 1 or 2, wherein the glass transition temperature Tg of the resin film is higher than the glass transition temperature Tg of the resin film.

4. The first temperature T １ The method for producing a laminated glass for a vehicle window according to any one of claims 1 to 3, wherein the temperature is higher than 60°C and not higher than 250°C.

5. The method for producing a laminated glass for vehicle windows according to any one of claims 1 to 4, further comprising a step of cooling the curved functional film to a temperature lower than a glass transition temperature Tg of the resin film between the forming step and the first pressure bonding step.

6. The area of ​​the main surface of the first mold is larger than the area of ​​a first main surface of the functional film that faces the main surface of the first mold, 6. The method for manufacturing a laminated glass for a vehicle window according to claim 1, wherein an area of ​​a main surface of the second mold is larger than an area of ​​a second main surface of the functional film that faces the main surface of the second mold.

7. The second temperature T ２ is 70° C. or more and 120° C. or less, 7. The method for producing a laminated glass for a vehicle window 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.

8. 8. The method for producing a laminated glass for a vehicle window according to claim 1, wherein a minimum value of a radius of curvature of each of the main surfaces of the first and second molding dies is 500 mm or more and 100,000 mm or less.

9. 9. The method for producing a laminated glass for a vehicle window according to claim 1, further comprising, after the first lamination step, a depressurization step of holding the first laminate at a gauge pressure of −70 kPa or less.

10. 10. The method for manufacturing a laminated glass for a vehicle window according to claim 1, 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, an infrared ray blocking film, and a radio wave control film.

11. The method for producing a laminated glass for a vehicle window according to claim 1 , wherein a power supply member is electrically connected to a peripheral edge portion of the functional film.

12. After the first pressure bonding step, the absolute pressure is 0.6 MPa or more and 1.3 MPa or less, and the third temperature T ３ A second crimping step of crimping the The third temperature T ３ is the second temperature T ２ and the first temperature T １ The method for producing a laminated glass for a vehicle window according to claim 1 , wherein the thickness of the laminated glass is less than 1 mm.

13. After the first pressure bonding step, the absolute pressure is 0.6 MPa or more and 1.3 MPa or less, and the third temperature T ３ A second crimping step of crimping the The third temperature T ３ is the second temperature T ２ The method for producing a laminated glass for a vehicle window according to any one of claims 1 to 11, wherein the temperature is lower than 100°C.

14. The third temperature T ３ The method for producing a laminated glass for a vehicle window according to claim 12 or 13, wherein the glass transition temperature Tg of the resin film is higher than the glass transition temperature Tg of the resin film.

15. 15. The method for producing a laminated glass for a vehicle window according to claim 1, wherein a plate misalignment between the first glass plate and the second glass plate is 1.5 mm or less along at least one side of the laminated glass for a vehicle window.

16. 16. The method for producing a laminated glass for a vehicle window according to any one of claims 1 to 15, wherein the interlayer film is one or more of a plasticized polyvinyl acetal resin, a plasticized polyvinyl chloride resin, a saturated polyester resin, a plasticized saturated polyester resin, a polyurethane resin, a plasticized polyurethane resin, an ethylene-vinyl acetate copolymer resin, an ethylene-ethyl acrylate copolymer resin, a cycloolefin polymer resin, and an ionomer resin.

17. 16. The method for producing a laminated glass for a vehicle window according to claim 1, wherein the interlayer film is made of one or two of a plasticized polyvinyl acetal resin and an ethylene-vinyl acetate copolymer resin.

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