Reflective film, method for manufacturing laminated glass, and laminated glass

Abstract

Provided is a reflective film, a method for manufacturing a laminated glass, and a laminated glass, which can suppress wrinkles at the end of the reflective film and have less change in the reflective wavelength range when two glass plates sandwich the reflective film to manufacture the laminated glass. The reflective film has wavelength-selective reflectivity, a heat shrinkage rate of more than 0.5% and less than 2.0% when held at 140°C for 30 minutes, and a notch portion at an edge portion of the reflective film.

Description

Technical Field

[0001] This invention relates to a reflective film that can be used as a combiner for a head-up display system, a method for manufacturing laminated glass having the reflective film, and the laminated glass itself. Background Technology

[0002] Currently, there is a so-called head-up display or head-up display system that projects images onto the windshield of a vehicle or other object to provide drivers or other users with various information such as maps, speed, and vehicle status.

[0003] A head-up display system can be constructed by using laminated glass, which consists of two glass plates sandwiching a semi-reflective film (reflective film), as a windshield.

[0004] Windshields of vehicles and other vehicles are curved into a three-dimensional shape. Therefore, laminated glass used as windshields is manufactured by placing a reflective film between two glass plates curved into a three-dimensional shape and then heating and pressing the two glass plates together. However, since the glass plates are three-dimensional while the reflective film is planar, there is a problem that the reflective film cannot follow the curved shape of the glass plates, resulting in wrinkles within the reflective film.

[0005] In contrast, a scheme was proposed to suppress wrinkle formation by keeping the thermal shrinkage rate of the reflective film within a specified range.

[0006] For example, Patent Document 1 describes a laminated glass in which a resin film is sandwiched between a first glass substrate and a second glass substrate via an adhesive layer, and has a generally annular hidden portion near the outer periphery. The thermal shrinkage rate of the resin film in the direction in which the thermal shrinkage rate is greatest exceeds 1% and is less than 2%, and the thermal shrinkage rate in the direction orthogonal to the direction exceeds 1% and is less than 2%. When the laminated glass is viewed from the front, the cut end of the resin film is disposed within a range of 10 mm in both the cut end direction of the laminated glass and the direction opposite to that direction relative to the inner periphery of the hidden portion.

[0007] Previous technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-086987 Summary of the Invention

[0010] The technical problem to be solved by the invention

[0011] In recent years, the performance requirements for laminated glass have been continuously increasing, demanding further suppression of wrinkles at the ends of the reflective film. However, according to the inventors' research, simply keeping the thermal shrinkage rate of the reflective film within a specified range is insufficient to adequately suppress wrinkle formation at its ends. In particular, when the glass sheet is significantly bent, simply keeping the thermal shrinkage rate of the reflective film within a specified range is insufficient to adequately suppress wrinkle formation.

[0012] Increasing the thermal shrinkage rate of the reflective film makes it easier to suppress wrinkles at its ends. However, when using a wavelength-selective reflective film that reflects light within a specific wavelength range and transmits light within other wavelength ranges, excessively increasing the thermal shrinkage rate will change the film's thickness, leading to a change in the reflected wavelength range. This will result in a decrease in reflectivity or a change in hue at the specified wavelength.

[0013] The objective of this invention is to solve this problem and to provide a reflective film, a method for manufacturing laminated glass, and a laminated glass that can suppress wrinkles at the ends of the reflective film and minimize changes in the range of reflected wavelengths when laminated glass is made by sandwiching a reflective film between two glass plates.

[0014] means for solving technical problems

[0015] [1] A reflective film having wavelength-selective reflectivity,

[0016] The average heat shrinkage rate when held at 140°C for 30 minutes is greater than 0.5% and less than 2.5%.

[0017] The reflective film has a cut at its edge.

[0018] [2] The reflective film according to [1] has a plurality of cuts.

[0019] [3] According to the reflective film described in [1] or [2], the cut portion has a curved portion.

[0020] The minimum radius of curvature of the curved section is 100 mm or more and 1700 mm or less.

[0021] [4] According to the reflective film described in [3], wherein,

[0022] The minimum radius of curvature of the curved portion is 100 mm or more and 900 mm or less.

[0023] [5] According to the reflective film described in [3] or [4], wherein,

[0024] The minimum radius of curvature of the curved portion is 100 mm or more and 700 mm or less.

[0025] [6] The reflective film according to any one of [3] to [5], wherein,

[0026] The minimum radius of curvature of the curved portion is 100 mm or more and 500 mm or less.

[0027] [7] The reflective film according to any one of [3] to [6], wherein,

[0028] The minimum radius of curvature of the curved portion is 100 mm or more and 300 mm or less.

[0029] [8] The reflective film according to any one of [1] to [7], wherein the depth D1 of the cut portion is 10 mm to 250 mm.

[0030] [9] The reflective film according to any one of [1] to [8] has a substrate and a reflective layer disposed on a main surface side of the substrate.

[0031]

[10] According to the reflective film described in [9], the reflective layer is a cholesterol-type liquid crystal layer.

[0032]

[11] According to the reflective film of [9] or

[10] , wherein the selective reflective center wavelength of the reflective layer is within the wavelength range of visible to infrared light.

[0033]

[12] A method for manufacturing laminated glass, wherein the laminated glass is manufactured by placing a reflective film as described in any one of [1] to

[11] between two glass plates and subjecting the two glass plates to a heat-pressing process.

[0034]

[13] According to the method for manufacturing laminated glass described in

[12] , a reflective film is disposed within 100 mm from the end edge of the glass plate to perform heat pressing treatment.

[0035]

[14] The method for manufacturing laminated glass according to

[12] or

[13] , wherein the maximum bending depth of the two glass plates is 15 mm or more.

[0036]

[15] A laminated glass having two glass plates and a reflective film disposed between the two glass plates,

[0037] The reflective film has wavelength-selective reflectivity.

[0038] The reflective film has cutouts at its edges.

[0039]

[16] According to the laminated glass described in

[15] , the maximum bending depth of the two glass plates is more than 15 mm.

[0040] Invention Effects

[0041] According to the present invention, a method for manufacturing laminated glass is provided, which can suppress wrinkles at the ends of the reflective film and minimize changes in the range of reflected wavelengths when laminated glass is made by sandwiching a reflective film between two glass plates. Attached Figure Description

[0042] Figure 1 This is a top view schematically illustrating an example of the reflective film of the present invention.

[0043] Figure 2 This is a cross-sectional view schematically illustrating an example of the reflective film of the present invention.

[0044] Figure 3 This is a top view schematically illustrating another example of the reflective film of the present invention.

[0045] Figure 4 This is a magnified view showing an example of another shape of the cut.

[0046] Figure 5 This is a magnified view showing an example of another shape of the cut.

[0047] Figure 6 This is a diagram showing an example of other shapes of the cut.

[0048] Figure 7 It is a magnified view used to illustrate the shape of the cut.

[0049] Figure 8 This is a conceptual diagram illustrating the manufacturing method of the laminated glass of the present invention.

[0050] Figure 9 This is a conceptual diagram illustrating the manufacturing method of the laminated glass of the present invention.

[0051] Figure 10 This is a top view schematically showing an example of laminated glass manufactured by the method of manufacturing laminated glass according to the present invention.

[0052] Figure 11 This is a schematic diagram illustrating the wrinkles that occur when using conventional reflective films.

[0053] Figure 12 This is a schematic diagram illustrating the wrinkles that occur when using conventional reflective films.

[0054] Figure 13 This is a schematic diagram illustrating the wrinkles that occur when using conventional reflective films.

[0055] Figure 14 This is a schematic diagram illustrating the change in thickness caused by the thermal shrinkage of the reflective film.

[0056] Figure 15 This is a top view schematically illustrating another example of the laminated glass of the present invention.

[0057] Figure 16 This is a diagram that conceptually illustrates an example of a head-up display using the laminated glass of the present invention.

[0058] Figure 17 This is a conceptual diagram illustrating the cutout portion of the reflective film in the embodiment.

[0059] Figure 18 This is a conceptual diagram illustrating the cutout portion of the reflective film in the embodiment.

[0060] Figure 19 This is a conceptual diagram illustrating the evaluation method in the embodiments. Detailed Implementation

[0061] Hereinafter, the reflective film, the method for manufacturing laminated glass, and the laminated glass of the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.

[0062] Furthermore, the figures described below are for illustrating examples of the present invention, and the present invention is not limited to the figures shown below.

[0063] Additionally, the "~" sign indicating a range of values ​​includes the values ​​on either side. For example, ε1 being α1 to β1 means that the range of ε1 includes both α1 and β1. In mathematical notation, this would be α1 ≤ ε1 ≤ β1.

[0064] Unless otherwise specified, "angles expressed in specific numerical values", "parallel", "perpendicular" and "orthogonal" angles include the error range that is generally allowed in the corresponding technical field.

[0065] Furthermore, "same" includes the error range that is usually allowed in the corresponding technical field, and "the entire surface" also includes the error range that is usually allowed in the corresponding technical field.

[0066] When referred to as "light," unless otherwise specified, it refers to visible light and natural light (unpolarized light). Visible light is the electromagnetic wave with wavelengths observable by the human eye, typically representing light in the wavelength range of 380–780 nm. Invisible light is light with wavelengths less than 380 nm or greater than 780 nm.

[0067] Furthermore, although not limited to this, the wavelength region of visible light in the 420–490 nm range is blue (B) light, the wavelength region of 495–570 nm range is green (G) light, and the wavelength region of 620–750 nm range is red (R) light.

[0068] "Visible light transmittance" refers to the visible light transmittance of light source A as specified in JIS (Japanese Industrial Standard) R 3212:2015 (Test Method for Safety Glass for Automobiles). Specifically, it is the transmittance calculated as follows: using light source A, the transmittance at each wavelength within the range of 380–780 nm is measured by a spectrophotometer. The transmittance at each wavelength is then multiplied by a weighted average based on the wavelength distribution and wavelength intervals of the visibility according to the CIE (International Commission on Illumination) light adaptability standard, and this weighted average is applied.

[0069] When referred to simply as "reflected light" or "transmitted light," it is used to include both scattered and diffracted light.

[0070] A "projection image" refers to an image projected based on light from the projector used, rather than an image based on the surrounding scenery such as what's in front of you. When viewed from the observer's perspective, a projection image can be observed as a virtual image floating in front of the reflective film on the windshield.

[0071] "Screen image" refers to an image displayed on a projector's drawing device or an image drawn on an intermediate image screen, etc., by a drawing device. As opposed to a virtual image, a screen image is a real image.

[0072] Images and projected images can be monochrome, multi-color (two or more colors), or full-color.

[0073] [Reflective film]

[0074] The reflective film of the present invention is a wavelength-selective reflective film.

[0075] The average heat shrinkage rate when held at 140°C for 30 minutes is greater than 0.5% and less than 2.5%.

[0076] The reflective film has a cutout at its edge.

[0077] Figure 1 The image shows a front view schematically illustrating an example of the reflective film of the present invention. Figure 1 The reflective film 10 shown has four cutouts 11 at its edge. Figure 1 The reflective film 10 shown is assembled into laminated glass used as a windshield, and therefore has a generally trapezoidal shape with its bottom edge curved outwards to form a convex shape, depending on the shape of the windshield, and has a cutout 11 that cuts through the edge of this generally trapezoidal shape. In the example shown, the reflective film 10 has cutouts 11 on each of its four sides. Furthermore, the cutouts 11 have a shape that is curved inwards to form a convex shape towards the inside of the reflective film 10. The cutouts 11 are respectively disposed approximately at the center of each side.

[0078] Here, the average thermal shrinkage rate of the reflective film 10 when held at 140°C for 30 minutes is greater than 0.5% and less than 2.5%.

[0079] Furthermore, the reflective film 10 has wavelength-selective reflectivity. For example, such as... Figure 2 As shown, the reflective film 10 has a reflective layer 12 composed of a cholesterol-type liquid crystal layer with wavelength selective reflectivity and a support 14 supporting the reflective layer 12.

[0080] The reflective film of the present invention is configured such that the average thermal shrinkage rate is within the above-mentioned range and has a notch at the edge. When laminated glass is made by placing the reflective film between two glass plates bent into a three-dimensional shape and heating and pressing the two glass plates together, wrinkles can be suppressed at the ends of the reflective film, and changes in the reflection wavelength range can be suppressed by suppressing changes in the thickness of the reflective film.

[0081] The function of the reflective film will be described in detail later.

[0082] Here, the average thermal shrinkage rate of the reflective film after being kept at 140°C for 30 minutes was measured as follows.

[0083] Strip-shaped test pieces are cut from the reflective film along any first direction and in directions at 45°, 90°, and 135° relative to the first direction. For example, the test piece is 150 mm long and 20 mm wide. A pair of reference lines are marked on the test piece at approximately 100 mm intervals along its length, and the length L between these reference lines is measured. The length L before heating is designated as L1.

[0084] Next, the test piece was vertically suspended in a hot air circulating oven, heated to 140°C and held for 30 minutes, then naturally cooled to room temperature and held for 60 minutes before re-measuring the length L. The heated length L was designated as L2. Based on the obtained lengths L1 and L2, the heat shrinkage rate was calculated using the following formula.

[0085] Heat shrinkage rate = ((L1-L2) / L1) × 100 [%)

[0086] The above-mentioned heat shrinkage rate was determined by using test pieces cut along the first direction and in directions at 45°, 90° and 135° relative to the first direction, and then averaged to obtain the average heat shrinkage rate of the reflective film.

[0087] From the viewpoint of being able to appropriately suppress the formation of wrinkles, the average thermal shrinkage rate of the reflective film is preferably 0.55% or more, more preferably 0.6% or more, and even more preferably 0.7% or more.

[0088] On the other hand, from the viewpoint of suppressing changes in the range of reflection wavelengths, the average thermal shrinkage rate of the reflective film is preferably 2.45% or less, more preferably 2.0% or less, and even more preferably 1.5% or less.

[0089] Furthermore, in Figure 1 In the example shown, the reflective film 10 is configured to have cutouts 11 on each of its four sides, but it is not limited to this; the reflective film only needs to have at least one cutout. For example, as Figure 3 As shown, it can also be configured such that each of the two opposite sides has a cutout portion 11. Furthermore, it is also possible to have two or more cutout portions on one side.

[0090] Furthermore, in Figure 1 In the example shown, the cutout 11 is an arc shape with a constant radius of curvature, but it is not limited to this. For example, as... Figure 4 As shown in the example, the shape of the cut-out portion 11 can also be a shape in which the radius of curvature changes depending on the position. Figure 4 In the example shown, the cutout 11 is approximately rectangular in shape, and the edge on the center side of the reflective film is curved into a convex shape towards the center. Furthermore, in this invention, the straight edge is considered to have an infinite radius of curvature. And, as... Figure 5 As shown, the shape of the cut portion 11 can also be a shape formed by combining multiple arc-shaped cuts. Figure 5 In the example shown, the cut portion 11 has a shape with a radius of curvature smaller than that of the cut portion, which is provided approximately at the center of the cut portion with a specified radius of curvature.

[0091] And, as Figure 6 As shown in the example, the cutout 11 can also be provided on the entire edge.

[0092] Minimum radius of curvature R of cut section 11 (reference) Figure 7 The minimum radius of curvature R of the cutout portion 11 is preferably 100 mm or more, more preferably 150 mm or more, and even more preferably 200 mm or more. Furthermore, the minimum radius of curvature R of the cutout portion 11 is preferably 1700 mm or less, more preferably 1200 mm or less, and even more preferably 1000 mm or less, particularly preferred in the order of 900 mm or less, 700 mm or less, 500 mm or less, and 300 mm or less. If the minimum radius of curvature of the cutout portion 11 is too small, the deflection of the film will concentrate in this part, potentially causing wrinkles. Therefore, the minimum radius of curvature R of the cutout portion 11 is preferably 100 mm or more. On the other hand, if the minimum radius of curvature of the cutout portion 11 is too large, the ratio of the area of ​​the reflective film to the area of ​​the laminated glass will decrease when assembled into the laminated glass. Furthermore, the boundary portion of the reflective film will be easily visually identifiable, potentially damaging the appearance. Therefore, the minimum radius of curvature R of the cutout portion 11 is preferably 1700 mm or less.

[0093] Here, as Figure 7 As shown, if the depth of the cut portion 11 is set as D1, the depth D1 of the cut portion is preferably 10mm to 250mm, more preferably 30mm to 230mm, and even more preferably 50mm to 200mm.

[0094] By keeping the depth D1 of the cut within the aforementioned range, it is possible to more appropriately suppress the formation of wrinkles while ensuring the area of ​​the reflective film.

[0095] In addition, the depth D1 of the cut is the maximum value of the distance between the line and the cut in a direction orthogonal to the line connecting the edge on which the cut is disposed and the two contact points of the cut.

[0096] The reflective wavelength range of the reflective film is not particularly limited, but it is preferably a portion of at least one of the visible and infrared light ranges. That is, the selected reflective center wavelength of the reflective film is preferably within the wavelength range of visible to infrared light. For example, in a reflective film having such... Figure 2 In the case of the reflective layer 12 shown, which is composed of a cholesterol-type liquid crystal layer, the selective reflection center wavelength of the cholesterol-type liquid crystal layer preferably exists in the wavelength range of visible light to infrared light. Furthermore, when the reflective film is assembled into a head-up display system, the reflective film preferably has reflective properties for visible light emitted from the projector.

[0097] Here, the reflective film has such Figure 2 In the case of the structure shown, which consists of a reflective layer 12 made of a cholesterol-type liquid crystal layer and a support 14, a stretched film is typically used as the support 14. The stretched film has residual stress, and therefore thermal shrinkage occurs due to the residual stress of the support 14. Therefore, by adjusting the residual stress of the support 14, the thermal shrinkage rate can be adjusted within the aforementioned range.

[0098] Furthermore, dielectric multilayer films can be used as reflective films with wavelength selective reflectivity. It is well known that dielectric multilayer films have a structure in which transparent films with high refractive index and transparent films with low refractive index are alternately stacked, and by adjusting the layer structure, light in the desired wavelength region can be reflected while light in other wavelength regions can be transmitted. When the reflective film is a dielectric multilayer film, a support body supporting the dielectric multilayer film can also be included. In this case, the thermal shrinkage rate can be adjusted within the aforementioned range by adjusting the residual stress of the support body. Furthermore, when each layer of the dielectric multilayer film is composed of a polymer, the thermal shrinkage rate can also be adjusted by the residual stress of the dielectric multilayer film itself.

[0099] <Support>

[0100] The support is a component that supports the reflective layer. The support is preferably transparent in the visible light region.

[0101] There are no restrictions on the material of the support. Examples of supports include polyesters such as polyethylene terephthalate (PET), polycarbonate, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cellulose derivatives, and silicone plastic films.

[0102] The thickness of the support body can be approximately 5.0 to 1000 μm, preferably 10 to 250 μm, and more preferably 15 to 90 μm.

[0103] <Reflective Layer>

[0104] There are no particular limitations on the reflective layer that has wavelength selective reflectivity; known reflective layers such as cholesterol-type liquid crystal layers and dielectric multilayer films can be used.

[0105] <<Cholesterol-type liquid crystal layer>>

[0106] Cholesterol-type liquid crystal layers are layers formed by fixing the helical orientation structure (helical structure) of liquid crystal compounds, indicating layers formed by fixing cholesterol-type liquid crystal phases.

[0107] Cholesterol-type liquid crystal layers can be layers that maintain the orientation of liquid crystal compounds that are cholesterol-type liquid crystal phases. Typically, a cholesterol-type liquid crystal layer can be a layer formed by polymerizing and curing a polymerizable liquid crystal compound into a cholesterol-type liquid crystal phase after it has been oriented to that state, through ultraviolet irradiation and heating, to create a non-flowing layer that also becomes oriented in a state unaffected by external fields or forces. Furthermore, in cholesterol-type liquid crystal layers, it is sufficient to maintain the optical properties of the cholesterol-type liquid crystal phase within the layer; the liquid crystal compound itself may no longer exhibit liquid crystal properties. For example, the polymerizable liquid crystal compound can be molecularized through a curing reaction, thereby losing its liquid crystal properties.

[0108] The selective reflection center wavelength λ of a cholesterol-type liquid crystal layer depends on the pitch P (=helical period) of the helical structure (helical orientation structure) in the cholesterol-type liquid crystal phase, and follows the relationship between the average refractive index n of the cholesterol-type liquid crystal layer and λ=n×P. From this equation, it can be seen that the selective reflection center wavelength can be adjusted by adjusting the value of n and / or the value of P.

[0109] In other words, the pitch P (one helical pitch) of a helical structure refers to the length of one turn of the helix along the helical axis, that is, the length along the helical axis when the directional vector (or the major axis direction if it is a rod-shaped liquid crystal) of the liquid crystal compound constituting the cholesterol-type liquid crystal phase rotates 360°. Typically, the helical axis of a cholesterol-type liquid crystal layer is aligned with the thickness direction of the cholesterol-type liquid crystal layer.

[0110] As an example, the selective reflection center wavelength and half-width of a cholesterol-type liquid crystal layer can be determined as follows.

[0111] When measuring the reflectance spectrum of a cholesterol-type liquid crystal layer from the normal direction using a spectrophotometer (JASCO Corporation, V-670), a transmittance reduction peak can be observed in the selected reflectance band. Let λ be the wavelength of the shorter wavelength side of the two wavelengths representing the minimum transmittance and the intermediate (average) transmittance before the reduction. l (nm), where the wavelength value on the longer wavelength side is set to λ. h If the reflection center wavelength λ and half-width Δλ are (nm), then the selection of the reflection center wavelength λ and half-width Δλ can be expressed by the following formula.

[0112] λ=(λ l +λ h ) / 2

[0113] Δλ=(λ h -λ l )

[0114] The wavelength of the selected reflection center, as determined above, is approximately the same as the wavelength located at the centroid of the reflection peak of the circularly polarized light reflection spectrum measured from the normal direction of the cholesterol-type liquid crystal layer.

[0115] The helical pitch of a cholesterol-type liquid crystal phase depends on the type and concentration of the chiral reagent used with the polymerizable liquid crystal compound; therefore, the desired pitch can be obtained by adjusting these factors. Furthermore, methods for determining the helix direction and pitch can be found in "Introduction to Liquid Crystal Chemistry Experiments" (compiled by the Japan Liquid Crystal Society, published by Sigma Publishing in 2007, p. 46) and "Liquid Crystal Handbook" (Liquid Crystal Handbook Editorial Committee, Maruzen Junkudo Bookstores Co., Ltd., p. 196).

[0116] (Method for fabricating cholesterol-type liquid crystal layers)

[0117] The following describes the materials and manufacturing methods for cholesterol-type liquid crystal layers.

[0118] Examples of materials used to form the aforementioned cholesterol-type liquid crystal layer include liquid crystal compositions containing polymerizable liquid crystal compounds and chiral reagents (optically active compounds). Depending on the requirements, the aforementioned liquid crystal composition, which is further mixed with surfactants and polymerization initiators and dissolved in a solvent, can be coated onto a support, an alignment layer, or a cholesterol-type liquid crystal layer serving as the bottom layer. After cholesterol-type alignment curing, the liquid crystal composition is cured to fix the layer, thereby forming a cholesterol-type liquid crystal layer.

[0119] (polymeric liquid crystal compound)

[0120] Polymerizable liquid crystal compounds can be rod-shaped or disc-shaped.

[0121] Examples of rod-shaped polymerizable liquid crystal compounds that form cholesterol-type liquid crystal layers include rod-shaped nematic liquid crystal compounds. Among these rod-shaped nematic liquid crystal compounds, azobenzene compounds, azo oxide compounds, cyanobiphenyl compounds, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane compounds, cyano-substituted phenylpyrimidine compounds, alkoxy-substituted phenylpyrimidine compounds, phenyl dioxane compounds, diphenylacetylene compounds, and alkenylcyclohexylbenzylnitrile compounds are preferred. Not only low-molecular-weight liquid crystal compounds but also high-molecular-weight liquid crystal compounds can be used.

[0122] Polymerizable liquid crystal compounds are obtained by incorporating polymeric groups into a liquid crystal compound. Examples of polymeric groups include unsaturated polymeric groups, epoxy groups, and aziridinyl groups, with unsaturated polymeric groups being preferred, and olefinic unsaturated polymeric groups being particularly preferred. Polymeric groups can be incorporated into the molecule of the liquid crystal compound by various methods. The number of polymeric groups in a polymerizable liquid crystal compound is preferably 1 to 6 per molecule, more preferably 1 to 3.

[0123] Examples of polymerizable liquid crystal compounds include those described in Makromol. Chem., Vol. 190, pp. 2255 (1989), Advanced Materials, Vol. 5, pp. 107 (1993), U.S. Patent No. 4,683,327, U.S. Patent No. 5,622,648, U.S. Patent No. 5,770,107, WO95 / 22586, WO95 / 24455, WO97 / 00600, WO98 / 23580, WO98 / 52905, Japanese Patent Application Publication No. 1-272,551, Japanese Patent Application Publication No. 6-16616, Japanese Patent Application Publication No. 7-110,469, Japanese Patent Application Publication No. 11-80081, and Japanese Patent Application Publication No. 2001-328,973. Two or more polymerizable liquid crystal compounds can be used simultaneously. Using two or more polymerizable liquid crystal compounds simultaneously can lower the alignment temperature.

[0124] Furthermore, the amount of polymerizable liquid crystal compound added to the liquid crystal composition is preferably 80 to 99.9% by mass relative to the mass of the solid components of the liquid crystal composition (excluding the mass of the solvent), more preferably 85 to 99.5% by mass, and particularly preferably 90 to 99% by mass.

[0125] (Chiral reagents: optically active compounds)

[0126] Chiral reagents have the function of inducing helical structures in cholesterol-type liquid crystal phases. The helix direction or helical pitch induced varies depending on the compound, thus the chiral compound can be selected according to the purpose.

[0127] There are no particular restrictions on the use of chiral reagents; known compounds can be used. Examples of chiral reagents include compounds described in various publications such as the Liquid Crystal Device Handbook (Chapter 3, Item 4-3, TN and STN using chiral reagents, page 199, compiled by Committee 142 of the Japanese Society for the Promotion of Science, 1989), Japanese Patent Application Publication No. 2003-287623, Japanese Patent Application Publication No. 2002-302487, Japanese Patent Application Publication No. 2002-80478, Japanese Patent Application Publication No. 2002-80851, Japanese Patent Application Publication No. 2010-181852, and Japanese Patent Application Publication No. 2014-034581.

[0128] Chiral reagents generally contain asymmetric carbon atoms, but axially asymmetric or surface-asymmetric compounds that do not contain asymmetric carbon atoms can also be used as chiral reagents. Examples of axially asymmetric or surface-asymmetric compounds include binaphthyl, helicene, p-cycloaranes, and their derivatives.

[0129] Chiral reagents can have polymerizable groups. When both the chiral reagent and the liquid crystal compound have polymerizable groups, a polymer having repeating units derived from the polymerizable liquid crystal compound and repeating units derived from the chiral reagent can be formed through a polymerization reaction of the chiral reagent and the polymerizable liquid crystal compound. In this manner, the polymerizable groups possessed by the chiral reagent are preferably of the same type as those possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable groups of the chiral reagent are preferably unsaturated polymerizable groups, epoxy groups, or aziridinyl groups, more preferably unsaturated polymerizable groups, and particularly preferably olefinic unsaturated polymerizable groups.

[0130] Furthermore, the chiral reagent can be a liquid crystal compound.

[0131] As chiral reagents, isosorbide derivatives, isomannitol derivatives, and binaphthyl derivatives are preferred. For isosorbide derivatives, commercially available products such as BASF's LC756 can be used.

[0132] The content of the chiral reagent in the liquid crystal composition is preferably 0.01 to 200 mol% of the amount of the polymerizable liquid crystal compound, more preferably 1 to 30 mol%. Furthermore, the content of the chiral reagent in the liquid crystal composition indicates the concentration (mass %) of the chiral reagent relative to the total solid components in the composition.

[0133] (Polymerization initiator)

[0134] The liquid crystal composition preferably contains a polymerization initiator. In the case of polymerization reaction carried out by ultraviolet irradiation, the polymerization initiator used is preferably a photopolymerization initiator capable of initiating polymerization reaction by ultraviolet irradiation.

[0135] Examples of photopolymerization initiators include α-carbonyl compounds (described in US Patent Nos. 2,367,661 and 2,367,670), azobin ethers (described in US Patent No. 2,448,828), α-hydrocarbon-substituted aromatic azobin compounds (described in US Patent No. 2,722,512), polynuclear quinone compounds (described in US Patent Nos. 3,046,127 and 2,951,758), combinations of triarylimidazolium dimers and p-aminophenyl ketones (described in US Patent No. 3,549,367), acridine and phenazine compounds (described in Japanese Patent Application Publication No. 60-105,667 and US Patent No. 4,239,850), and acylphosphine oxide compounds (described in Japanese Patent Application Publication No. 63-40,799). Japanese Patent Application Publication No. 5-29234, Japanese Patent Application Publication No. 10-95788, Japanese Patent Application Publication No. 10-29997, Japanese Patent Application Publication No. 2001-233842, Japanese Patent Application Publication No. 2000-80068, Japanese Patent Application Publication No. 2006-342166, Japanese Patent Application Publication No. 2013-114249, Japanese Patent Application Publication No. 2014-137466, Japanese Patent Publication No. 4223071, Japanese Patent Application Publication No. 2010-262028, Japanese Patent No. 2014-500852, etc., oxime compounds (described in Japanese Patent Application Publication No. 2000-66385, Japanese Patent No. 4454067), and oxadiazole compounds (described in US Patent No. 4212970). For example, one can also refer to paragraphs 0500 to 0547 of Japanese Patent Application Publication No. 2012-208494.

[0136] Acylphosphine oxide compounds or oxime compounds are preferred as polymerization initiators.

[0137] As an acylphosphine oxide compound, commercially available products such as IRGACURE 810 (compound name: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) manufactured by BASF JAPAN LTD. can be used. As an oxime compound, commercially available products such as IRGACUREOXE01 (manufactured by BASF), IRGACURE OXE02 (manufactured by BASF), TR-PBG-304 (manufactured by Changzhou Qiangli Electronic New Materials Co., Ltd.), ADEKA ARKLS NCI-831, ADEKA ARKLS NCI-930 (manufactured by ADEKA CORPORATION), and ADEKA ARKLS NCI-831 (manufactured by ADEKA CORPORATION) can be used.

[0138] Polymerization initiators can be used in single or multiple ways.

[0139] The content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1 to 20% by mass relative to the content of the polymerizable liquid crystal compound, more preferably 0.5 to 5% by mass.

[0140] (Cross-linking agent)

[0141] To improve the strength and durability of the cured film, the liquid crystal composition may contain a crosslinking agent. Preferably, a crosslinking agent that cures using ultraviolet light, heat, or moisture is used.

[0142] There are no particular limitations on the crosslinking agent; it can be selected appropriately according to the purpose. Examples of crosslinking agents include: polyfunctional acrylate compounds such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; epoxy compounds such as glycidyl methacrylate and ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-dimethylolbutanol-tris[3-(1-aziridinyl)propionate] and 4,4-bis(ethyleneiminocarbonylamino)diphenylmethane; isocyanate compounds such as hexamethylene diisocyanate and biuret-type isocyanate; polyoxazoline compounds with oxazoline groups on the side chain; and alkoxysilane compounds such as vinyltrimethoxysilane and N-(2-aminoethyl)3-aminopropyltrimethoxysilane. Furthermore, known catalysts can be used depending on the reactivity of the crosslinking agent, which can improve film strength and durability, as well as productivity. These can be used individually or in combination.

[0143] The content of the crosslinking agent is preferably 3 to 20% by mass, more preferably 5 to 15% by mass. By making the content of the crosslinking agent 3% by mass or more, the effect of increasing the crosslinking density can be obtained, and by making the content of the crosslinking agent 20% by mass or less, the stability of the cholesterol-type liquid crystal layer can be prevented from decreasing.

[0144] In addition, "(meth)acrylate" is used to mean "either or both of acrylate and methacrylate".

[0145] (Orientation control agent)

[0146] Orientation control agents that help stabilize or rapidly form planar orientations in liquid crystal compositions can be added. Examples of orientation control agents include fluoro(meth)acrylate polymers described in paragraphs

[0018] to

[0043] of Japanese Patent Application Publication No. 2007-272185, compounds represented by formulas (I) to (IV) described in paragraphs

[0031] to

[0034] of Japanese Patent Application Publication No. 2012-203237, compounds described in paragraphs

[0073] to

[0096] of Japanese Patent Application Publication No. 2013-076052, compounds described in paragraphs

[0011] to

[0031] of Japanese Patent Application Publication No. 2013-047204, and compounds described in Japanese Patent Application Publication No. 2013-113913.

[0147] In addition, as an orientation control agent, it can be used alone or two or more at the same time.

[0148] The amount of the orientation control agent added to the liquid crystal composition is preferably 0.01 to 10% by mass relative to the total mass of the polymerizable liquid crystal compound, more preferably 0.01 to 5% by mass, and particularly preferably 0.02 to 1% by mass.

[0149] (Other additives)

[0150] Furthermore, the liquid crystal composition may contain at least one additive selected from various additives such as surfactants and polymerizable monomers used to adjust the surface tension of the coating to achieve uniform thickness. Additionally, polymerization inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, colorants, and metal oxide particles may be further added to the liquid crystal composition as needed, without degrading optical performance.

[0151] Cholesterol-type liquid crystal layers can be formed by coating a liquid crystal composition, which is prepared by dissolving a polymerizable liquid crystal compound, a polymerization initiator, and chiral reagents and surfactants added as needed, in a solvent onto a support or alignment layer, drying it to obtain a coating film, and then irradiating the coating film with activation light to polymerize the cholesterol-type liquid crystal composition, thereby forming a cholesterol-type liquid crystal layer with fixed cholesterol regularity.

[0152] (solvent)

[0153] There are no particular restrictions on the solvents used to prepare liquid crystal compositions, and they can be selected appropriately according to the purpose, but organic solvents are preferred.

[0154] There are no particular limitations on organic solvents; they can be selected appropriately depending on the purpose. Examples include ketones, haloalkanes, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, and ethers. One or more of these can be used simultaneously. Among them, ketones are particularly preferred when considering environmental impact.

[0155] (Coating, Orientation, Polymerization)

[0156] There are no particular limitations on the coating method for the liquid crystal composition on the support and alignment layer, etc., and it can be appropriately selected according to the purpose. Examples of coating methods include wire rod coating, curtain coating, extrusion coating, direct gravure coating, reverse gravure coating, mold coating, spin coating, dip coating, spray coating, and slide coating. Furthermore, it can also be carried out by transferring the liquid crystal composition separately coated on the support.

[0157] The liquid crystal molecules are oriented by heating the coated liquid crystal composition. The heating temperature is preferably below 200°C, more preferably below 130°C. This orientation process yields an optical thin film in which the polymerizable liquid crystal compound is twisted and oriented in a direction substantially perpendicular to the film surface, having a helical axis.

[0158] The liquid crystal composition can be cured by further polymerizing the oriented liquid crystal compound. Polymerization can be either thermal polymerization or photopolymerization using light irradiation, but photopolymerization is preferred. Ultraviolet light is preferably used for light irradiation. The irradiation energy is preferably 20 mJ / cm². 2 ~50J / cm 2 More preferably, it is 100–1500 mJ / cm 2 .

[0159] To promote photopolymerization, light irradiation can be performed under heating conditions or in a nitrogen atmosphere. The wavelength of the irradiated ultraviolet light is preferably 350–430 nm. From a stability point of view, a higher polymerization rate is preferred, preferably 70% or more, and more preferably 80% or more. The polymerization rate can be determined by measuring the proportion of polymerizable functional groups consumed by infrared absorption spectroscopy.

[0160] (Orientation layer)

[0161] When the reflective layer is a cholesterol-type liquid crystal layer, the reflective film may include an alignment layer for orienting the liquid crystal compound as the bottom layer for coating the liquid crystal composition when forming the cholesterol-type liquid crystal layer.

[0162] Orientation layers can be formed by methods such as: triboelectric treatment of organic compounds (resins such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamide-imide, polyether-imide, polyamide, and modified polyamide), tilted evaporation of inorganic compounds, formation of layers with microgrooves, and accumulation of organic compounds (e.g., ω-trisanoic acid, dioctadecylmethylammonium chloride, and methyl stearate) using the Langmuir-Blodgett process (LB film). Furthermore, layers that acquire orientation functions by applying an electric field, a magnetic field, or irradiating light can also be used as orientation layers.

[0163] For example, the alignment layer made of polymer is preferably coated with a liquid crystal composition after a rubbing treatment. The rubbing treatment can be carried out by wiping the surface of the polymer layer along a predetermined direction using paper or cloth.

[0164] Alternatively, the liquid crystal composition can be coated onto the surface of the support or the surface of the support after rubbing treatment, without setting an alignment layer. When a temporary support is used to form the liquid crystal layer, the alignment layer can be peeled off together with the temporary support and does not become a layer constituting the reflective element.

[0165] The thickness of the orientation layer is preferably 0.01 to 5.0 μm, and more preferably 0.05 to 2.0 μm.

[0166] <<Dielectric Multilayer Film>>

[0167] Dielectric multilayer films are known to be composed of multiple dielectric films stacked together, consisting of materials such as aluminum oxide, magnesium fluoride, zirconium oxide, and silicon oxide. Dielectric multilayer films have a structure that alternately stacks high-refractive-index and low-refractive-index dielectric films. By adjusting the layer structure of the dielectric films, they can reflect light in a desired wavelength range and transmit light in other wavelength ranges.

[0168] As a dielectric multilayer film, commercially available products can be used, such as H256 manufactured by SHIBUYAOPTICALCO.,LTD.

[0169] In addition to the aforementioned support and reflective layer, the reflective film may also have various layers found in reflective films used in laminated glass. For example, it may have a phase retardation layer, a polarization conversion layer, a heat-sealing layer (adhesive layer), etc.

[0170] [Manufacturing methods for laminated glass]

[0171] The method for manufacturing laminated glass according to the present invention is as follows:

[0172] The aforementioned reflective film is disposed between two glass plates, and the two glass plates are then subjected to a heat-pressing process. In this invention, in addition to using the aforementioned reflective film, known laminated glass manufacturing methods can also be used in the method for manufacturing laminated glass.

[0173] It can usually be manufactured by the following method: after sandwiching laminated glass between two glass plates with an interlayer film and a reflective film, repeat the heat treatment and pressure treatment several times (using rubber rollers, etc.), and finally use an autoclave or the like to carry out heat treatment under pressure.

[0174] The method for manufacturing the laminated glass of the present invention will now be described using the accompanying drawings.

[0175] like Figure 8 As shown, a reflective film 10 and an interlayer film 36 are disposed between the curved first glass plate 28 and the second glass plate 30, and a heat-pressing process is performed. Thus, as... Figure 9 As shown, a curved laminated glass is fabricated by sequentially stacking a first glass plate 28, an intermediate film 36, a reflective film 10, and a second glass plate 30. Figure 10 As shown, the reflective film 10 of the laminated glass has a notch 11 at the edge.

[0176] Furthermore, in the manufacturing method of laminated glass, laminated glass can also be manufactured as follows: after preheating and pressing the reflective film 10 and the intermediate film 36 to form a laminate, the laminate is placed between the first glass plate 28 and the second glass plate 30, and a heat pressing process is performed.

[0177] Here, as mentioned above, if a reflective film is placed between two glass plates bent into a three-dimensional shape, and the two glass plates are then heated and pressed together, the following problem arises: the glass plates are three-dimensional, but the reflective film is planar; therefore, as... Figure 11 As shown, the reflective film 100 will have excess material relative to the glass plates (28, 30), causing the reflective film 100 to be unable to follow the curved shape of the glass plate, such as... Figure 12 As shown, the excess portion of the reflective film 100 exhibits wrinkles. (As...) Figure 13 As shown, such wrinkles tend to form at the ends of the reflective film 100.

[0178] To address these wrinkles, increasing the thermal shrinkage rate of the reflective film will cause it to shrink in the planar direction, thus suppressing the formation of excess portions and wrinkles. However, when using a wavelength-selective reflective film that reflects light within a specific wavelength range while transmitting light within other wavelength ranges, excessively increasing the thermal shrinkage rate will alter the film's thickness, causing a change in the reflected wavelength range. Consequently, this results in a decrease in reflectivity or a change in hue at the specified wavelengths.

[0179] For example, in the case where the reflective film 100 has a reflective layer 112 composed of a cholesterol-type liquid crystal layer and a support 114, such as Figure 14 As shown, the support 114 contracts in the planar direction, therefore the reflective layer 112 also contracts in the planar direction, resulting in elongation in the thickness direction. As mentioned above, the selective reflection wavelength of the cholesterol-type liquid crystal layer depends on the pitch of the helical structure of the cholesterol-type liquid crystal phase, but if the thickness of the cholesterol-type liquid crystal layer is elongated, the pitch of the helical structure also becomes longer. Therefore, the selective reflection wavelength will change.

[0180] Furthermore, in a dielectric multilayer film, the phase difference of reflected light at the interfaces of each layer is enhanced at certain wavelengths due to the difference in optical path length caused by the thickness of the high-refractive-index layer and the low-refractive-index layer, and weakened at other wavelengths by canceling each other out. This results in the reflection of certain wavelengths of light and the transmission of other wavelengths. In other words, the selective reflection wavelength of a dielectric multilayer film depends on the thickness of each layer. Therefore, when the reflective film (reflective layer) is a dielectric multilayer film, if the thickness of the dielectric multilayer film increases, the thickness of each layer also increases, leading to a change in the selective reflection wavelength.

[0181] In contrast, the method for manufacturing laminated glass according to the present invention uses a reflective film with an average thermal shrinkage rate exceeding 0.5% and less than 2.5% and having a notch at the edge. By making the thermal shrinkage rate of the reflective film exceed 0.5%, the film can shrink in the surface direction, thus suppressing the formation of excess portions. Furthermore, having a notch at the edge also suppresses wrinkling at the ends of the reflective film by preventing wrinkles from forming on the excess portions. Moreover, by making the thermal shrinkage rate of the reflective film less than 2.5%, changes in the reflective wavelength range caused by variations in the thickness of the reflective film can be suppressed. Therefore, a decrease in reflectivity at a specified wavelength can be suppressed, and changes in hue can be suppressed.

[0182] Here, the temperature and pressure used for heating and pressing the two glass plates are the same as those used in conventional laminated glass manufacturing methods. The heating temperature is preferably 130°C to 150°C, more preferably 135°C to 145°C, and even more preferably 140°C to 145°C.

[0183] In the manufacturing method of laminated glass using the reflective film of the present invention, the generation of wrinkles can be more appropriately suppressed. Therefore, it can also be appropriately applied to cases where the maximum bending depth of the glass plate used in laminated glass is large, such as 15 mm or more, 20 mm or more, or 30 mm or more.

[0184] The maximum bending depth, also known as the lateral bending amount, is an indicator of the degree of bending. A larger value indicates a greater degree of bending and a greater likelihood of wrinkles forming near the outer periphery. According to the present invention, wrinkles near the outer periphery can be effectively suppressed, particularly for reflective films with a large degree of bending. Here, the maximum bending depth (lateral bending amount) is the length, expressed in mm, of the perpendicular line drawn from the deepest point at the bottom of the bend to the straight line when the laminated glass is arranged with its convex side facing down and a straight line is drawn connecting the midpoints of a pair of opposing long sides of the laminated glass.

[0185] Furthermore, the method for manufacturing laminated glass using the reflective film of the present invention can also be suitably applied to cases where a portion of the reflective film is disposed within 100 mm of the end edge of the glass plate for heat pressing. The closer to the end edge of the glass plate, the more prone the reflective film is to wrinkling. In contrast, according to the present invention, even when a portion of the reflective film is disposed within 100 mm of the end edge of the glass plate, edge wrinkling can be effectively suppressed.

[0186] Furthermore, the method for manufacturing laminated glass using the reflective film of the present invention can also be suitably applied to the shortest distance L1 (refer to) from the end edge of the glass plate on each side to the reflective film. Figure 15 This applies to cases where the reflective film, with a size within 100 mm, undergoes heat pressing. In other words, the method for manufacturing laminated glass using the reflective film of the present invention can also be suitably applied to cases where the area of ​​the reflective film, assuming no notches, is close to the area of ​​the glass plate. The closer the size of the reflective film (i.e., the area of ​​the reflective film assuming no notches) is to the glass plate, the more prone the reflective film is to wrinkling. In contrast, according to the present invention, even when the size of the reflective film is close to the size of the glass plate, wrinkling at the edges can be effectively suppressed.

[0187] Furthermore, in Figure 9 In the example shown, as a preferred embodiment, an interlayer film 36 is disposed between the first glass plate 28 and the reflective film 10 for heat pressing, but this is not a limitation. For example, an interlayer film may also be disposed between the second glass plate 30 and the reflective film 10. Furthermore, an adhesive layer may be provided between the glass plate and the reflective film.

[0188] There are no particular restrictions on the thickness of the glass plate, as long as it is around 0.5 to 5.0 mm, preferably 1.0 to 3.0 mm, and more preferably 2.0 to 2.3 mm. The materials or thicknesses of the first and second glass plates can be the same or different.

[0189] Furthermore, as mentioned above, the maximum bending depth of the glass plate is preferably 15 mm or more.

[0190] (Intermediate membrane)

[0191] As the interlayer (interlayer sheet), any known interlayer used as an interlayer (intermediate layer) in laminated glass can be used. For example, a resin film containing a resin selected from the group consisting of polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer, and chlorinated resins can be used. The aforementioned resin is preferably the main component of the interlayer. Furthermore, the main component refers to a component that accounts for 50% or more by mass of the interlayer.

[0192] Of the above-mentioned resins, polyvinyl butyral and ethylene-vinyl acetate copolymers are preferred, and polyvinyl butyral is more preferred. The resin is preferably a synthetic resin.

[0193] Polyvinyl butyral can be obtained by acetalizing polyvinyl alcohol using butyral. The preferred lower limit for the degree of acetalization of the aforementioned polyvinyl butyral is 40%, the preferred upper limit is 85%, the more preferred lower limit is 60%, and the more preferred upper limit is 75%.

[0194] Polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate, typically using polyvinyl alcohol with a saponification degree of 80 to 99.8 mol%.

[0195] Furthermore, the preferred lower limit for the degree of polymerization of polyvinyl alcohol is 200, and the preferred upper limit is 3000. If the degree of polymerization of polyvinyl alcohol is 200 or higher, the penetration resistance of the resulting laminated glass is not easily reduced; if it is below 3000, the resin film has good formability, and the rigidity of the resin film does not become too large, thus resulting in good processability. A more preferred lower limit is 500, and a more preferred upper limit is 2000.

[0196] (Including the intermediate film of the reflective film)

[0197] Interlayers for laminated glass, including reflective films, can be formed by laminating the reflective film onto the surface of the aforementioned interlayers. Alternatively, they can be formed by sandwiching the reflective film between two aforementioned interlayers. The two interlayers can be identical or different, but are preferably identical.

[0198] When laminating the reflective film and the interlayer, known lamination methods can be used, but a lamination process is preferred. The lamination process is preferably carried out under certain heating and pressure conditions to prevent the laminate and the interlayer from peeling off after processing.

[0199] For stable lamination, the surface temperature of the interlayer on the bonding side is preferably 50–130°C, more preferably 70–100°C.

[0200] During lamination, pressure is preferably applied. There are no restrictions on the pressure conditions, but it is preferred to be less than 2.0 kg / cm³. 2(less than 196 kPa), more preferably 0.5–1.8 kg / cm². 2 (49–176 kPa), more preferably 0.5–1.5 kg / cm². 2 (49~147kPa).

[0201] Furthermore, when the reflective film has a support and the reflective film itself undergoes thermal shrinkage, the support can be peeled off during lamination, immediately after lamination, or just before lamination. That is, the reflective film attached to the intermediate film obtained after lamination may not have a support.

[0202] An example of a method for manufacturing an intermediate film including a reflective film includes:

[0203] (1) Step 1: The reflective film is laminated onto the surface of the first intermediate film to obtain the first laminate; and

[0204] (2) The second step is to attach the second intermediate film to the side of the reflective film in the first laminate that is opposite to the side of the first intermediate film.

[0205] For example, in the first step, the reflective film and the first intermediate film are bonded together without the support and the first intermediate film facing each other. Next, the support is peeled off from the reflective film. Then, in the second step, the second intermediate film is bonded to the surface after the support has been peeled off. Thus, an intermediate film including a reflective film without a support can be manufactured. Furthermore, using this intermediate film including the reflective film, laminated glass with a reflective film that does not have a support can be easily manufactured.

[0206] In order to stably peel off the support without damaging it, the temperature of the support when peeling it off from the reflective film is preferably 40°C or higher, and more preferably 40 to 60°C.

[0207] Laminated glass

[0208] The laminated glass of the present invention is a laminated glass having two glass plates and a reflective film disposed between the two glass plates.

[0209] The reflective film has wavelength-selective reflectivity.

[0210] The reflective film has cutouts at its edges.

[0211] The laminated glass of the present invention is a laminated glass made using the reflective film of the present invention described above. That is, in the laminated glass of the present invention, the reflective film has wavelength selective reflectivity and has a notch at the edge.

[0212] In laminated glass, a reflective film is disposed between a first glass plate and a second glass plate. Preferably, the laminated glass is configured such that an interlayer film (intermediate film sheet) is provided at least at one location between the first glass plate and the reflective film, and between the reflective film and the second glass plate. Alternatively, an adhesive layer may be provided at least at one location between the first glass plate and the reflective film, and between the reflective film and the second glass plate.

[0213] Furthermore, as described in the above-described method for manufacturing laminated glass, a portion of the reflective film is preferably disposed within 100 mm of the end edge of the glass plate. Moreover, the reflective film is preferably the shortest distance L1 from the end edge of the glass plate to the reflective film on each side of the glass plate (refer to...). Figure 15 The sizes are all within 100mm.

[0214] Furthermore, as described above, the laminated glass of the present invention may also include cases where the maximum bending depth of the two glass plates of the laminated glass is greater than 15 mm, 20 mm, or 30 mm.

[0215] In a laminated glass used as a windshield, for example, a first glass panel is disposed on the side of the HUD opposite to the visual recognition side of the image (outer side of the vehicle), and a second glass panel is disposed on the visual recognition side (inner side of the vehicle). Furthermore, in the laminated glass of the present invention, the terms "first" and "second" in the first and second glass panels are not technically significant, but are provided for ease of distinguishing the two glass panels. Therefore, it is also possible for the first glass panel to be on the inner side of the vehicle, and the second glass panel to be on the outer side of the vehicle.

[0216] The first and second glass plates, etc., can be glass plates commonly used for windshields. For example, glass plates with visible light transmittance of 73% and 76% or less, or even 80% or less, such as high-heat-insulating green glass, can be used. Even when using glass plates with low visible light transmittance, it is possible to produce a windshield with visible light transmittance of 70% or more at the location of the reflective film by using the reflective film of the present invention.

[0217] Furthermore, when the first and second glass panels are curved glass, it is preferable to sequentially stack the reflective film and the first curved glass on the convex surface of the second curved glass on the inner side of the vehicle.

[0218] The following describes a windshield and a head-up display (HUD) using laminated glass with the reflective film of the present invention.

[0219] [windshield]

[0220] By using laminated glass with the reflective film of the present invention, it is possible to provide a windshield with a projection image display function.

[0221] Windshields refer to the ordinary window glass and windproof glass of vehicles such as automobiles and trams, airplanes, ships, two-wheeled vehicles, and amusement equipment. Windshields are preferably used as the front window and windproof glass located at the front of the vehicle in the direction of travel.

[0222] There is no limitation on the visible light transmittance of the windshield, but a higher transmittance is preferred. The visible light transmittance of the windshield is preferably 70% or more, more preferably more than 70%, further preferably 75% or more, and especially preferably 80% or more.

[0223] Preferably, the aforementioned visible light transmittance is satisfied at any location on the windshield, and particularly preferably at the location where the reflective film is present. The reflective film of the present invention has wavelength-selective reflectivity, thus improving the transmittance of visible light outside the selectively reflected wavelength range. Therefore, regardless of which type of glass commonly used for windshields is used, the aforementioned visible light transmittance can be satisfied.

[0224] The shape of the windshield is not limited and can be appropriately determined according to the object on which the windshield is installed. The windshield can be, for example, flat or a three-dimensional shape with curved surfaces such as concave or convex surfaces. In the windshields that are applicable and molded as vehicle windshields, the surfaces that are the upward direction, the observer's side, the driver's side, and the interior side, etc., which are the visual recognition sides during normal use, can be determined.

[0225] In windshields, the reflective film can have a uniform thickness or an uneven thickness. For example, it can have a wedge-shaped cross-section, as described in Japanese Patent Application Publication No. 2011-505330 for vehicle glass, and the reflective film can have an uneven thickness, but it is preferable that the reflective film has a uniform thickness.

[0226] The reflective film of this invention functions as a combiner in a HUD. In a HUD, the combiner refers to an optical component capable of displaying an image projected from a projector in a visually recognizable manner, and simultaneously allowing the observation of information such as scenery located on the opposite side of the incident surface of the projected light when viewing the combiner from the incident surface of the projected image. In other words, the combiner functions as an optical path combiner that overlays and displays both ambient light and the projected image.

[0227] The reflective film can be applied to the entire surface of the windshield, or it can be applied to a portion of the surface of the windshield.

[0228] When the reflective film is installed on part of the windshield, it can be placed at any location on the windshield. However, when used as a HUD, it is preferable to display the virtual image in a position that is easily visible to an observer such as the driver. For example, the position of the reflective film on the windshield can be determined based on the relationship between the position of the driver's seat of the vehicle equipped with the HUD and the position of the projector.

[0229] Furthermore, the cutouts in the reflective film are preferably not positioned in a way that allows for visually identifiable image display when used as a HUD.

[0230] [HUD (Head-Up Display)]

[0231] A windshield can be used as a component of a HUD. A HUD preferably includes a projector.

[0232] Projector

[0233] A projector is a device for projecting light or images, including a device for projecting a depicted image and emitting projected light carrying the image to be displayed.

[0234] In a HUD, the projector only needs to be configured to allow the projected light carrying the image to be displayed to be incident on a reflective film in the windshield.

[0235] In a HUD, the projector includes a drawing device, which preferably reflects and displays a virtual image as an image drawn on a small intermediate image screen via a combiner.

[0236] The projector can utilize a known projector used in HUDs. Furthermore, the projector preferably has a variable imaging distance for the virtual image (i.e., the imaging position of the virtual image).

[0237] Methods for changing the imaging distance of the virtual image in a projector include, for example, moving the image generation surface (screen) (see Japanese Patent Application Publication No. 2017-21302), switching between multiple optical paths with different optical path lengths (see WO2015 / 190157), changing the optical path length by inserting and / or moving a mirror, changing the focal length by using a lens group as an imaging lens, moving the projector 22, switching between multiple projectors with different imaging distances of the virtual image, and using a zoom lens (see WO2010 / 116912), etc.

[0238] In addition, the projector can be a projector that can continuously change the imaging distance of the virtual image, or a projector that can switch the imaging distance of the virtual image between multiple points, such as two or three points.

[0239] Here, in the virtual image of the projected light projected by the projector, it is preferable that the imaging distances of at least two virtual images differ by more than 1 meter. Therefore, when the projector is capable of continuously changing the imaging distance of the virtual images, it is preferable that the imaging distance of the virtual images can be changed by more than 1 meter. By using such a projector, it is preferable that appropriate responses can be made even when the driver's line of sight distance differs greatly, such as when driving at normal speeds on ordinary roads and driving at high speeds on highways.

[0240] (Description equipment)

[0241] A drawing device can be a device that displays an image for itself, or it can be a device that emits light capable of drawing an image.

[0242] In a drawing device, light from a light source can be adjusted using drawing methods such as an optical modulator, a laser brightness modulation mechanism, or a light deflection mechanism for drawing. A drawing device refers to a device that includes a light source and, depending on the drawing method, also includes an optical modulator, a laser brightness modulation mechanism, or a light deflection mechanism for drawing.

[0243] (light source)

[0244] There are no restrictions on the light source; known light sources used in projectors, drawing equipment, and displays, such as LEDs (light-emitting diodes), organic light-emitting diodes (OLEDs), discharge tubes, and laser light sources, can be used.

[0245] LEDs and discharge tubes are suitable light sources for drawing devices that emit linearly polarized light, and therefore LEDs are preferred, and especially preferred. This is because the emission wavelength of an LED is not continuous in the visible light region, and therefore it is suitable for use with a combiner for a linearly polarized light reflective layer that exhibits selective reflectivity in a specific wavelength region.

[0246] (Description method)

[0247] The method of depiction can be chosen based on the light source used, and there are no particular limitations.

[0248] Examples of display methods include fluorescent tubes, LCD (Liquid Crystal Display) and LCOS (Liquid Crystal on Silicon) displays using liquid crystals, DLP (Digital Light Processing) displays, and laser scanning methods. A fluorescent tube display, which integrates the light source with the display, can be used. LCD displays are preferred as a display method.

[0249] In LCD and LCOS modes, light of different colors is modulated and combined by a light modulator and then emitted from the projection lens.

[0250] DLP (Digital Micromirror Device) is a display system that uses a DMD, which is equipped with micromirrors equivalent to the number of pixels to depict images and emits light from a projection lens.

[0251] The scanning method involves scanning light on a screen and creating an image using the afterimages seen by the naked eye. For example, see Japanese Patent Application Publication Nos. 7-270711 and 2013-228674. In laser-based scanning, beams of different colors of laser light (e.g., red, green, and blue light) modulated by brightness are focused into a single beam using a beam-combining optical system or a focusing lens. This beam is then scanned by a light deflection mechanism and projected onto an intermediate image screen, as described later.

[0252] In the scanning method, the brightness modulation of each color laser beam (e.g., red, green, and blue light) can be performed directly as a change in the intensity of the light source, or it can be performed through an external modulator. Examples of light deflection mechanisms include galvanometer mirrors, combinations of galvanometer mirrors and prisms, and MEMS (Micro Electro Mechanical Systems), with MEMS being preferred. Examples of scanning methods include random scanning and grating scanning, with grating scanning being preferred. In grating scanning, for example, the laser beam can be driven at a resonant frequency in the horizontal direction and a sawtooth wave in the vertical direction. The scanning method does not require a projection lens, thus facilitating device miniaturization.

[0253] The light emitted from the drawing device can be either linearly polarized light or natural light (unpolarized light).

[0254] In drawing devices using LCD or LCOS methods, and in drawing devices using laser light sources, the emitted light is essentially linearly polarized light. When the emitted light of a drawing device is linearly polarized and includes light of multiple wavelengths (colors), the polarization directions (transmission axis directions) of the multiple wavelengths are preferably the same. It is known that the polarization directions of red, green, and blue light emitted by commercially available drawing devices are sometimes not uniform within their wavelength ranges (see Japanese Patent Application Laid-Open No. 2000-221449). Specifically, examples are known where the polarization direction of green light is orthogonal to the polarization directions of red and blue light.

[0255] (The middle part resembles a screen)

[0256] As described above, the drawing device can be a device that uses an intermediate image screen. An "intermediate image screen" is a screen on which an image is drawn. That is, when the light emitted from the drawing device is not yet visually recognizable as an image, the drawing device uses that light to form a visually recognizable image on the intermediate image screen. The image drawn on the intermediate image screen can be projected onto the combiner by light transmitted through the intermediate image screen, or it can be reflected from the intermediate image screen and projected onto the combiner.

[0257] Examples of intermediate image screens include scattering films, microlens arrays, and rear projection screens. When plastic materials are used as intermediate image screens, if the intermediate image screen is birefringent, the polarization plane and intensity of the polarized light incident on the intermediate image screen are disturbed, which can easily cause color inhomogeneity in the combiner (reflective film). However, by using a phase difference film with a specified phase difference, this problem of color inhomogeneity can be reduced.

[0258] As an intermediate image screen, an intermediate image screen with the function of diffusing incident light for its transmission is preferred. This is because it is possible to magnify and display the projected image. For example, a screen composed of a microlens array can be cited as such an intermediate image screen. Microlenses used in HUDs are described, for example, in Japanese Patent Application Publication Nos. 2012-226303, 2010-145745, and 2007-523369.

[0259] Projectors may include reflectors that adjust the light path of the projected light formed by the drawing device.

[0260] For HUDs that use windshields as reflective films, please refer to Japanese Patent Application Publication No. 2-141720, Japanese Patent Application Publication No. 10-96874, Japanese Patent Application Publication No. 2003-98470, US Patent No. 5013134, and Japanese Patent Application Publication No. 2006-512622, etc.

[0261] Windshields are particularly useful for HUDs that combine light sources such as lasers, LEDs, and OLEDs (organic light-emitting diodes) that emit light at discontinuous wavelengths within the visible light region. This is because the center wavelength of selective reflection from the cholesterol-type liquid crystal layer can be adjusted according to each emission wavelength. Furthermore, they can also be used for projection onto displays that show light polarization, such as LCDs (liquid crystal displays).

[0262] The incident light from the projector can enter from any direction on the windshield, such as up, down, left, or right, as long as it corresponds to the direction of visual perception. For example, it can be configured to enter from below at an angled angle during use.

[0263] Furthermore, the reflective film on the windshield only needs to be configured to reflect incident light.

[0264] As mentioned above, a HUD (head-up display) can be a projection system where the position of the virtual image is variable. By making the position of the virtual image variable, the driver can visually identify the virtual image more comfortably and conveniently.

[0265] The virtual image imaging position is the position where the driver of the vehicle can visually identify the virtual image, usually when viewed from the driver's side, for example, at a position more than 1000mm in front of the windshield.

[0266] Next, refer to Figure 16 Let's explain HUD in more detail.

[0267] Figure 16 This is a schematic diagram illustrating an example of a head-up display having a reflective film according to an embodiment of the present invention.

[0268] The HUD20 includes a projector 22 and a laminated glass (hereinafter also referred to as a windshield) 24, which serves as a windshield, and is used, for example, in vehicles such as cars. Furthermore, the constituent elements of the HUD20 are as described above.

[0269] In HUD20, such as Figure 16 As shown in the conceptual diagram, the windshield 24 has a first glass plate 28, a second glass plate 30, a reflective film 10, an interlayer film 36, and an adhesive layer 38.

[0270] Reflective film 10 is Figure 1 The reflective film 10 shown has wavelength-selective reflectivity and has a notch at the edge.

[0271] The vertical direction Y of the windshield 24 corresponds to the vertical direction of the vehicle on which the windshield 24 is installed, and is defined as the lower side (ground side) and the upper side (opposite side). Additionally, when the windshield 24 is installed in a vehicle, it may sometimes be installed at an angle for structural or design reasons. In this case, the vertical direction Y is along the surface 25 of the windshield 24. Surface 25 refers to the outer surface side of the vehicle.

[0272] Projector 22 is as described above. Projector 22 can utilize any known projector for HUDs, as long as it can emit projection light carrying the image to be displayed. Furthermore, the imaging distance of the virtual image (i.e., the imaging position of the virtual image) is preferably variable in projector 22.

[0273] In HUD20, projector 22 projects light onto windshield 24 (second glass panel 30).

[0274] The windshield 24 is a so-called laminated glass, and has an interlayer 36, a reflective film 10 and an adhesive layer 38 between the first glass plate 28 and the second glass plate 30.

[0275] The projected light emitted by the projector 22 is incident from the surface 30a of the second glass plate 30. The reflective film 10 has wavelength selective reflectivity, and the selective reflection wavelength of the reflective film is set to reflect the projected light emitted by the projector 22.

[0276] The reflective film 10 is attached to the first glass plate 28 via the intermediate film 36 and to the second glass plate 30 via the adhesive layer 38, thereby being sandwiched between the first glass plate 28 and the second glass plate 30.

[0277] In this invention, the first glass plate 28 and the second glass plate 30 of the windshield 24 are preferably arranged substantially parallel to each other.

[0278] Both the first glass plate 28 and the second glass plate 30 are known types of glass (glass plates) used for windshields of vehicles, etc. Therefore, the forming materials, thickness, and shape can be the same as those used for known windshields.

[0279] Interlayer 36 is used to prevent glass from entering the vehicle and splattering in the event of an accident, and is further used to bond the reflective film 10 and the first glass panel 28. Interlayer 36 can be any known interlayer (intermediate layer) used for windshields as laminated glass. Examples of materials forming interlayer 36 include polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer, chlorinated resins, and polyurethane.

[0280] Furthermore, there is no limitation on the thickness of the interlayer 36; it can be set to the same thickness as the interlayer of a known windshield, corresponding to the forming material, etc.

[0281] The adhesive layer 38 is, for example, a layer made of a coating adhesive. The reflective film 10 is attached to the second glass plate 30 via the adhesive layer 38. Alternatively, in the windshield of the present invention, the reflective film 10 may be attached to the second glass plate 30 via an interlayer film instead of the adhesive layer 38. Furthermore, if the reflective film 10 is smaller than the interlayer film 36 on which the first glass plate 28 and the reflective film 10 are attached, the reflective film 10 may also be attached to the second glass plate 30 via the interlayer film 36.

[0282] The adhesive layer 38 is not limited; any known adhesive layer composed of a coating-type adhesive can be used as long as the required transparency of the windshield 24 is ensured and the reflective film 10 and the glass can be adhered with the necessary adhesion force. The adhesive layer 38 can use materials such as PVB, the same as the interlayer film 36. Alternatively, the adhesive layer 38 can use acrylic adhesives, etc. Furthermore, as shown below, the adhesive layer 38 can also use the same materials as the aforementioned adhesive layers.

[0283] The adhesive layer 38 may be formed of adhesive in the same way as the adhesive layer described above.

[0284] From the perspective of curing methods, adhesives can be categorized into hot-melt, thermosetting, light-curing, reaction-curing, and pressure-sensitive adhesives that do not require curing. Furthermore, any type of adhesive can use compounds such as acrylates, urethanes, urethane acrylates, epoxy compounds, epoxy acrylates, polyolefins, modified olefins, polypropylenes, ethylene-vinyl alcohol, vinyl chloride, chloroprene rubber, cyanoacrylates, polyamides, polyimides, polystyrene, and polyvinyl butyral as raw materials.

[0285] From the perspective of operability and productivity, light-curing is preferred as the curing method. From the perspective of optical transparency and heat resistance, acrylate-based, urethane acrylate-based, and epoxy acrylate-based raw materials are preferred.

[0286] The adhesive layer 38 can be a layer formed using a high-transparency adhesive transfer tape (OCA tape). As a high-transparency adhesive transfer tape, commercially available products for image display devices can be used, and in particular, commercially available products for the surface of the image display section of an image display device can be used. Examples of commercially available products include adhesive sheets (PD-S1, etc.) manufactured by PANAC Co., Ltd., and adhesive sheets from the MHM series of NICHIEI KAKOH CO.,LTD.

[0287] There is no limitation on the thickness of the adhesive layer 38. Therefore, as long as the thickness is appropriately set according to the forming material of the adhesive layer 38, sufficient adhesion can be obtained.

[0288] If the adhesive layer 38 is too thick, it may be impossible to attach the reflective film 10 to the first glass plate 28 or the second glass plate 30 while ensuring sufficient planarity. With this in mind, the thickness of the adhesive layer 38 is preferably 0.1 to 800 μm, more preferably 0.5 to 400 μm.

[0289] Furthermore, the windshield 24 has an adhesive layer 38 between the reflective film 10 and the second glass plate 30, and the reflective film 10 and the first glass plate 28 are attached through an interlayer film 36, but it is not limited to this. That is, it can also be configured to have an adhesive layer between the reflective film 10 and the first glass plate 28, and an interlayer film between the reflective film 10 and the second glass plate 30.

[0290] Furthermore, the windshield 24 may be configured such that it does not have an interlayer film 36, and the reflective film 10 and the first glass plate 28 and the reflective film 10 and the second glass plate 30 are attached using an adhesive layer 38.

[0291] In HUD20, the windshield 24 has the following structure: a reflective film 10 is provided between the first glass plate 28 and the second glass plate 30, the reflective film 10 is attached to the second glass plate 30 by an adhesive layer 38, and the reflective film 10 is attached to the first glass plate 28 by an interlayer film 36.

[0292] like Figure 16 As shown, in HUD20, the observer of the image, i.e. the driver D, observes the virtual image of the projected image of the projector 22, which is projected by the projector 22 and reflected by the windshield 24.

[0293] The present invention is basically as described above. The reflective film, the manufacturing method of the laminated glass, and the laminated glass of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various improvements or modifications can be made without departing from the spirit of the present invention.

[0294] For example, the reflective film of the present invention can be configured to reflect infrared light, and the reflective film can be assembled into laminated glass as a heat-insulating film. When the reflective film of the present invention is used as a heat-insulating film that shields infrared light, wrinkles at the ends of the reflective film can be suppressed during the manufacture of laminated glass. Furthermore, it is possible to suppress the decrease in heat insulation performance due to changes in the reflective wavelength range of the reflective film.

[0295] Example

[0296] The following examples further illustrate the features of the present invention. The materials, reagents, quantities, proportions, and operations shown in the following examples can be appropriately modified without departing from the spirit of the invention. Therefore, the scope of the present invention is not limited to the following examples.

[0297] [Example 1]

[0298] (Composition for forming phase difference layer)

[0299] A phase difference layer forming composition with the following composition is prepared by mixing the following ingredients.

[0300] Composition for forming phase difference layer

[0301]

[0302] [Chemical Formula 1]

[0303] Mixture 1

[0304]

[0305] The value is a percentage of mass.

[0306] [Chemical Formula 2]

[0307] Orientation control agent 1

[0308]

[0309] [Chemical Formula 3]

[0310] Orientation control agent 2

[0311]

[0312] (Compositions CL1 and CL2 for forming cholesterol-type liquid crystal layers)

[0313] The cholesterol-type liquid crystal layer forming composition CL1, which forms a cholesterol-type liquid crystal layer with a selective reflection center wavelength of 550 nm, and the cholesterol-type liquid crystal layer forming composition CL2, which forms a cholesterol-type liquid crystal layer with a selective reflection center wavelength of 800 nm, are prepared by mixing the following components to obtain the cholesterol-type liquid crystal layer forming composition with the following composition.

[0314] Composition for forming cholesterol-type liquid crystal layers

[0315]

[0316] Using cholesterol-type liquid crystal layer forming compositions CL1 and CL2, a monolayer cholesterol-type liquid crystal layer with a film thickness of 3 μm was formed on a temporary support in the same manner as the fabrication of the reflective film shown below, and the reflective properties of visible light were confirmed.

[0317] As a result, all the cholesterol-type liquid crystal layers produced were right-handed circularly polarized light reflective layers. Regarding the selection of the center wavelength of reflection, the cholesterol-type liquid crystal layer formed by the cholesterol-type liquid crystal layer forming composition CL1 had a wavelength of 550 nm, and the cholesterol-type liquid crystal layer formed by the cholesterol-type liquid crystal layer forming composition CL2 had a wavelength of 800 nm.

[0318] (Composition for forming polarization conversion layer)

[0319] A composition for forming a polarization conversion layer with the following composition is prepared by mixing the following components.

[0320] Composition for forming polarization conversion layer

[0321]

[0322] When a cholesterol-type liquid crystal layer is formed by adjusting the formulation amount of the dextrorotatory chiral reagent LC756 in the above composition, the composition for forming the polarization conversion layer is prepared to achieve the desired selective reflection center wavelength λ. The selective reflection center wavelength λ is determined by fabricating a 3 μm thick monolayer of cholesterol-type liquid crystal layer on a temporary support and measuring it using FTIR (manufactured by PerkinElmer Co., Ltd., Spectrum Two).

[0323] The film thickness *d* of a helical alignment structure can be represented by "the pitch *P* of the helical alignment structure × the number of pitches". As mentioned above, the pitch *P* of the helical alignment structure refers to the length of one pitch of the helical alignment structure, which is one pitch when the helical liquid crystal compound is rotated 360°. Furthermore, in a cholesterol-type liquid crystal layer, the selective reflection center wavelength *λ* coincides with "the length of one pitch *P* × the average in-plane refractive index *n*" (λ = P × *n*). Therefore, the pitch *P* is "the selective reflection center wavelength *λ* / the average in-plane refractive index *n*" (P = λ / n).

[0324] Thus, in the case of forming a cholesterol-type liquid crystal layer, the composition for forming a polarization conversion layer is prepared such that the selective reflection center wavelength λ is 7000 nm.

[0325] <Preparation of cellulose acylated membranes>

[0326] A cellulose acylated film with a thickness of 40 μm was prepared using the method described in Example 20 of International Publication No. 2014 / 112575. Furthermore, the residual stress and thermal shrinkage rate were adjusted by regulating the stretching conditions.

[0327] <Saponification of cellulose acylated membranes>

[0328] The prepared cellulose acylated membrane is passed through a dielectric heating roller at 60°C to raise the surface temperature of the membrane to 40°C. Then, an alkaline solution with the following composition is applied using a bar coater at a coating rate of 14 mL / m. 2 The coating is applied to one side of the film and held for 10 seconds in a steam-type far-infrared heater (manufactured by Noritake Co., Ltd.) heated to 110°C.

[0329] Next, using a bar coater, 3 mL / m of pure water was coated. 2 .

[0330] Next, after repeated washing with water using a spray coating machine and dehydration using an air knife three times, the mixture is dried in a drying zone at 70°C for 5 seconds to produce a saponified cellulose acylated film.

[0331] The in-plane phase difference of the cellulose acylated membrane, as determined by AxoScan, was 1 nm.

[0332] Composition of alkaline solutions

[0333]

[0334]

[0335] <Formation of Orientation Film>

[0336] Using a wire rod coating machine, a coating solution for forming an orientation film with the following composition was applied at a rate of 24 mL / m. 2 The coating is applied to the saponified surface of the saponified cellulose acylate film obtained above, and dried with warm air at 100°C for 120 seconds to obtain an oriented film with a thickness of 0.5 μm.

[0337] Coating solution for oriented film formation

[0338]

[0339] (Modified polyvinyl alcohol)

[0340] [Chemical Formula 4]

[0341]

[0342] (Fabrication of reflective film)

[0343] A cellulose acylated membrane with the fabricated orientation membrane was used as a support. The orientation membrane surface of the support was subjected to a friction treatment (man-made fiber cloth, pressure: 0.1 kgf (0.98 N), rotation speed: 1000 rpm (revolutions per minute), conveying speed: 10 m / min, number of cycles: one reciprocating motion).

[0344] The friction treatment is carried out in such a way that the angle α between the friction direction Sa and the long side direction H of the temporary support S is 50° clockwise with the long side direction H as the reference.

[0345] After the phase difference layer forming composition was applied to the friction-treated surface of the support using a wire rod, it was dried.

[0346] Next, it was placed on a hot plate at 50°C in an environment with an oxygen concentration below 1000ppm, and then tested with an electrodeless lamp, a "D bulb" (60mW / cm²), manufactured by Fusion UV Systems. 2 The liquid crystal phase was fixed by irradiating it with ultraviolet light for 6 seconds. Thus, a phase retardation layer with its thickness adjusted to achieve the desired frontal phase retardation (i.e., the desired frontal delay) was obtained.

[0347] The delay of the formed phase difference layer, as measured by AxoScan, was 142 nm.

[0348] At room temperature, the composition CL1 for forming a cholesterol-type liquid crystal layer is coated onto the surface of the phase reversal layer using a wire rod to form a dry film with a thickness of 0.55 μm after drying, thus obtaining the coating layer.

[0349] After drying the coating layer at room temperature for 30 seconds, it was heated for 2 minutes in an atmosphere of 85°C. Then, under conditions with an oxygen concentration below 1000 ppm, it was tested using a Fusion UV Systems D lamp (90 mW / cm²). 2 A lamp was used to irradiate the liquid crystal phase with ultraviolet light at 60°C and 60% output for 6–12 seconds to fix the cholesterol-type liquid crystal phase, resulting in a cholesterol-type liquid crystal layer with a thickness of 0.55 μm. This cholesterol-type liquid crystal layer is a green reflective cholesterol-type liquid crystal layer that selectively reflects green light.

[0350] Next, the same process was repeated on the surface of the obtained cholesterol-type liquid crystal layer using the cholesterol-type liquid crystal layer forming composition CL2, to stack a layer of cholesterol-type liquid crystal layer forming composition CL2 with a thickness of 0.80 μm. This cholesterol-type liquid crystal layer is a red-reflective cholesterol-type liquid crystal layer that selectively reflects red light.

[0351] Next, a polarization conversion layer forming composition is coated onto the surface of the formed cholesterol-type liquid crystal layer to form a film with a thickness of 1.7 μm, thus forming a polarization conversion layer.

[0352] In addition, a polarization conversion layer was formed in the same manner as the formation of the cholesterol-type liquid crystal layer described above.

[0353] As described above, the polarization conversion layer has a selective reflection center wavelength (reflection center wavelength) of 7000 nm when forming a cholesterol-type liquid crystal layer.

[0354] Thus, a reflective film is obtained by stacking a phase retardation layer, two cholesteric liquid crystal layers, and a polarization conversion layer on a substrate.

[0355] The reflective film is cut into a shape in which the reflective film is disposed 50 mm inside each side of the first and second glass plates used in the laminated glass. That is, the reflective film is cut into a shape in which each side is similar to the first and second glass plates but shorter by about 100 mm.

[0356] Here, the first and second glass panels are made of glass panels with a curved shape similar to that of a vehicle windshield (90% visible light transmittance) and a maximum bending depth of 20 mm.

[0357] Next, when configuring laminated glass as a vehicle windshield, a cutout is formed in the center of the lower edge in the vertical direction of the reflective film (see reference). Figure 17 The lower edge of the reflective film is prone to wrinkling. The width A of the cut is set to 600 mm, and the depth is set to 170 mm upwards in the vertical direction. That is, the cut is a quadrilateral shape. Furthermore, the radius of curvature R1 of the corner of the cut is set to 10 mm. Therefore, the minimum radius of curvature of the cut is 10 mm.

[0358] The reflective film of the present invention is produced by means of the above methods.

[0359] In addition, in the following description, the lower edge of the reflective film in the vertical direction when laminated glass is used as a windshield for a vehicle will be referred to as the lower edge, and the upper edge of the reflective film in the vertical direction will be referred to as the upper edge.

[0360] The average thermal shrinkage rate of the reflective film produced by the above method, when held at 140°C for 30 minutes, was 0.6%.

[0361] [Example 2]

[0362] The stretching conditions of the cellulose acylate membrane were adjusted, and a reflective film was fabricated by lamination and cutting in the same manner as in Example 1.

[0363] Furthermore, the in-plane phase difference of the cellulose acylate film, measured by AxoScan, was 1 nm. Additionally, the average thermal shrinkage rate of the reflective film was 1.2%.

[0364] [Example 3]

[0365] Furthermore, such as Figure 18 As shown, the reflective film is configured to have a cutout formed in the center of the upper edge of the reflective film. Otherwise, the reflective film is manufactured in the same manner as in Example 1. That is, the reflective film of Example 3 has two cutouts.

[0366] The width B of the cut at the center of the upper edge is set to 600 mm, and the depth is set to 170 mm downwards in the vertical direction. Furthermore, the radius of curvature R2 of the corner of the cut is set to 10 mm. Therefore, the minimum radius of curvature of this cut is 10 mm.

[0367] [Example 4]

[0368] The radius of curvature R1 of the corner of the cut portion formed at the center of the lower edge is set to 100 mm, and the radius of curvature R2 of the corner of the cut portion formed at the center of the upper edge is set to 100 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 3. The minimum radius of curvature of the cut portion of the reflective film in Example 4 is 100 mm.

[0369] [Example 5]

[0370] The radius of curvature R1 of the corner of the cut portion formed at the center of the lower edge is set to 300 mm, and the radius of curvature R2 of the corner of the cut portion formed at the center of the upper edge is set to 300 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 3. The minimum radius of curvature of the cut portion of the reflective film in Example 5 is 300 mm.

[0371] [Example 6]

[0372] The heat-sealing layer is formed on the side of the reflective film opposite to the friction-treated surface of the support. Otherwise, the reflective film is manufactured in the same manner as in Example 5.

[0373] The average thermal shrinkage rate of the produced reflective film is 0.6%.

[0374] (Formation of the heat-sealing layer)

[0375] Using a wire bar, the following heat-sealing coating liquid is applied to the side opposite to the friction-treated surface of the support, and then heated at 100°C for 1 minute to form a heat-sealing layer (adhesive layer) with a thickness of 1.0 μm.

[0376] (Coating liquid for heat-sealing layer formation)

[0377] Mix the following components to prepare a coating liquid for heat-sealing layer formation.

[0378] Coating liquid for heat-sealing layer formation

[0379]

[0380] Regarding the 5% MiBK dispersion of inorganic microparticles (AEROSIL RX300, manufactured by NIPPON AEROSIL CO.,LTD., with an average primary particle size of 7 nm), the inorganic microparticles were added to MiBK (methyl isobutyl ketone) and stirred for 30 minutes using a magnetic stirrer to achieve a solid concentration of 5% by mass. Then, the dispersion was prepared by ultrasonic dispersion for 10 minutes using an ultrasonic disperser (manufactured by SMT Co.,Ltd., Ultrasonic Homogenizer UH-600S).

[0381] A portion of the obtained dispersion was collected for the determination of the average secondary particle size, and the average secondary particle size of the silica particles in the dispersion was determined using a Microtrac MT3000 (manufactured by MicrotracBEL Corp.), which showed to be 190 nm.

[0382] [Example 7]

[0383] (Composition for forming thermal insulation layer)

[0384] The following components are mixed to prepare a right-handed circularly polarized light reflective composition for forming a heat insulation layer.

[0385] Right-hand circularly polarized light reflective composition for forming heat insulation layer

[0386]

[0387]

[0388] When a cholesterol-type liquid crystal layer is formed by adjusting the formulation amount of the dextrorotatory chiral reagent LC756 in the above-mentioned dextrorotatory circularly polarized light reflective composition for forming a heat insulation layer, the dextrorotatory circularly polarized light reflective composition for forming a heat insulation layer is prepared such that the selective reflection center wavelength λ is 1000 nm.

[0389] Next, the following components are mixed to prepare a left-handed circularly polarized light reflective composition for forming a heat insulation layer with the following composition.

[0390] Left-handed circularly polarized light reflective composition for forming heat insulation layer

[0391]

[0392] Left-handed reagent (L1)

[0393] [Chemical Formula 5]

[0394]

[0395] When a cholesterol-type liquid crystal layer is formed by adjusting the formulation amount of the left-handed chiral reagent L1 in the left-handed circularly polarized light reflecting composition for forming the above-mentioned heat insulation layer, the left-handed circularly polarized light reflecting composition for forming the heat insulation layer is prepared such that the selective reflection center wavelength λ is 1000 nm.

[0396] Using a right-handed circularly polarized light reflective composition for forming a heat insulation layer, a monolayer cholesteric liquid crystal layer with a film thickness of 3 μm was fabricated on a substrate in the same manner as the fabrication of the reflective film shown below, and the reflective properties were confirmed.

[0397] As a result, the cholesterol-type liquid crystal layer produced is a right-handed circularly polarized light reflector layer, with a selected reflection center wavelength (center wavelength) of 1000 nm.

[0398] The results were similarly confirmed using a heat-insulating layer to form a left-handed circularly polarized light reflective composition. The resulting cholesterol-type liquid crystal layer was a left-handed circularly polarized light reflective layer, with a selected reflection center wavelength (center wavelength) of 1000 nm.

[0399] A right-handed circularly polarized light reflective layer was formed by coating a right-handed circularly polarized light reflective composition with a film thickness of 5 μm on the friction-treated surface of the support using the same method as in Example 1. Furthermore, the right-handed circularly polarized light reflective layer was formed in the same manner as the cholesterol-type liquid crystal layer in Example 1.

[0400] Next, a left-handed circularly polarized light reflective layer with a thickness of 5 μm was coated onto the right-handed circularly polarized light reflective layer to form a heat-insulating layer. Furthermore, the left-handed circularly polarized light reflective layer was formed in the same manner as the cholesterol-type liquid crystal layer in Example 1.

[0401] In this way, a reflective film is produced by stacking a right-handed circularly polarized light reflective layer and a left-handed circularly polarized light reflective layer on the support.

[0402] The reflective film was cut into the same shape as in Example 5 to produce a reflective film with slits. The average thermal shrinkage rate of the produced reflective film was 0.6%.

[0403] [Example 8]

[0404] As shown below, an infrared reflective film is formed by alternately stacking nine Nb2O5 layers as high-refractive-index dielectric layers and SiO2 layers as low-refractive-index dielectric layers on a cellulose acylate film prepared in the same manner as in Example 1 using magnetron sputtering.

[0405] Furthermore, each Nb₂O₅ layer was formed as follows: A mixed gas of 5% by volume oxygen mixed with argon was introduced using an NBO target (manufactured by AGC Ceramics Co., Ltd., trade name: NBO), while precipitating at a pressure of 0.1 Pa, a frequency of 20 kHz, and a power density of 5.1 W / cm². 2 Pulse sputtering with a reverse pulse width of 5μsec.

[0406] Furthermore, each SiO2 layer is formed as follows: a mixed gas of 27% by volume oxygen mixed with argon is introduced using a Si target, while an electric field is applied at a pressure of 0.3 Pa, a frequency of 20 kHz, and an electric field density of 3.8 W / cm². 2 Pulse sputtering with a reverse pulse width of 5μsec.

[0407] The thickness of each Nb2O5 layer and SiO2 layer is adjusted by changing the film formation time. From the support side, the layers are Nb2O5 layer (95nm) / SiO2 layer (153nm) / Nb2O5 layer (95nm) / SiO2 layer (153nm) / Nb2O5 layer (95nm) / SiO2 layer (153nm) / Nb2O5 layer (95nm) / SiO2 layer (25nm) / Nb2O5 layer (10nm).

[0408] The infrared reflective film was cut into the same shape as in Example 5 to obtain a reflective film with a slit. The average thermal shrinkage rate of the produced reflective film was 0.6%.

[0409] [Example 9]

[0410] The radius of curvature R1 of the corner of the cut portion formed at the center of the lower edge is set to 90 mm, and the radius of curvature R2 of the corner of the cut portion formed at the center of the upper edge is set to 90 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 3. The minimum radius of curvature of the cut portion of the reflective film in Example 9 is 90 mm.

[0411] [Example 10]

[0412] The cut at the center of the lower edge is rounded. The depth D of the cut is set to 170mm upwards in the vertical direction, and the radius of curvature R of the arc is set to 500mm (reference). Figure 7 Furthermore, the cutout at the center of the upper edge is also rounded. The depth D of the cutout is 170 mm downwards in the vertical direction, and the radius of curvature R of the arc is 500 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 3. The minimum radius of curvature of the cutout in the reflective film of Example 10 is 500 mm.

[0413] [Example 11]

[0414] The radius of curvature R of the arc of the cut portion formed at the center of the lower edge is set to 700 mm, and the radius of curvature R of the arc of the cut portion formed at the center of the upper edge is set to 700 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 10. The minimum radius of curvature of the cut portion of the reflective film in Example 11 is 700 mm.

[0415] [Example 12]

[0416] The radius of curvature R of the arc of the cut portion formed at the center of the lower edge is set to 900 mm, and the radius of curvature R of the arc of the cut portion formed on the upper edge is set to 900 mm. Otherwise, the reflective film is manufactured in the same manner as in Example 10. The minimum radius of curvature of the cut portion of the reflective film in Example 12 is 900 mm.

[0417] [Comparative Example 1]

[0418] The average thermal shrinkage rate of the reflective film was changed by adjusting the stretching conditions of the cellulose acylate film. Otherwise, the reflective film was produced by the same method as in Example 1.

[0419] Furthermore, the in-plane phase difference of the cellulose acylate film, measured by AxoScan, was 1 nm. The average thermal shrinkage rate of the fabricated reflective film was 0.4%.

[0420] [Comparative Example 2]

[0421] The average thermal shrinkage rate of the reflective film was changed by adjusting the stretching conditions of the cellulose acylate film. Otherwise, the reflective film was produced by the same method as in Example 1.

[0422] Furthermore, the in-plane phase difference of the cellulose acylate film, measured by AxoScan, was 1 nm. The average thermal shrinkage rate of the fabricated reflective film was 2.6%.

[0423] [Comparative Example 3]

[0424] The reflective film was fabricated in the same manner as in Example 1, except that no cuts were provided.

[0425] [evaluate]

[0426] As described below, laminated glass was fabricated using the prepared reflective film, and the generation of wrinkles, changes in the color tone of reflected light, and appearance were evaluated.

[0427] (Fabrication of laminated glass)

[0428] Two curved glass sheets, each 900mm long and 1450mm wide, with a maximum bending depth of 20mm, were made using a 2mm thick glass plate (90% visible light transmittance) to serve as a windshield for a vehicle. The dimensions are for the longest portion of the glass.

[0429] A PVB film, cut to the same size and 0.38 mm thick, was placed on the first glass plate as an intermediate film. A reflective film, manufactured to the same dimensions, was then placed on the intermediate film. The reflective film was positioned such that each edge was 50 mm away from each edge of the glass plate.

[0430] A second glass plate was placed on the reflective film.

[0431] After holding the laminate at 90°C and below 100 kPa (1 atmosphere) for one hour, it is heated at 140°C and 1.3 MPa (13 atmospheres) for 30 minutes using an autoclave (manufactured by KURIHARASEISAKUSHO Co., Ltd.) to remove air bubbles and produce laminated glass.

[0432] (Evaluation of wrinkles)

[0433] like Figure 19 Natural light was incident on the laminated glass at an angle θ of 80°, and the presence or absence of wrinkles was observed by visually inspecting the light reflected by the reflective film. The results were evaluated based on the following criteria.

[0434] • A: The formation of wrinkles has been almost unconfirmed.

[0435] • B: Wrinkles appear upon close inspection, but they are not obvious.

[0436] • C: Almost no wrinkles are produced, but wrinkles can be observed in some areas.

[0437] • D: Wrinkles were observed and were quite noticeable in appearance.

[0438] (Evaluation of reflective hue)

[0439] The reflective hue was observed using the same method as that used to generate wrinkles, and the laminated glass pieces were evaluated against the following criteria.

[0440] • A: The color tone is uniform throughout the entire area of ​​the reflective film.

[0441] •B: Some unevenness in tone was observed at the end of the reflective film.

[0442] (Appearance evaluation)

[0443] like Figure 19 Natural light was incident on each of the laminated glass pieces at an angle θ of 60°, and the overall appearance of the laminated glass was observed with the naked eye. The shape of the boundary between the parts with and without the reflective coating was evaluated based on the following criteria.

[0444] • A: It is not easy to visually identify the boundary based on the incision.

[0445] •B: The boundary between the part with the reflective film and the part without the reflective film is wider, making it easy to visually identify based on the cut, but there is no problem in terms of quality.

[0446] The results are shown in Table 1.

[0447] [Table 1]

[0448]

[0449] As shown in Table 1, compared to the comparative examples, the embodiments of the present invention are able to suppress wrinkles while suppressing changes in reflective hue. On the other hand, the average thermal shrinkage rate of the reflective film in Comparative Example 1 is low, thus wrinkles are generated at the ends of the reflective film. Furthermore, the average thermal shrinkage rate of the reflective film in Comparative Example 2 is high, thus wrinkle generation is suppressed, but some unevenness in reflective hue is observed at the ends of the reflective film. This is presumably because the reflective film shrinks significantly, resulting in localized changes in reflective properties. Additionally, Comparative Example 3 lacks a notch, thus wrinkles are generated.

[0450] In Examples 1 and 2, wrinkles were observed at the upper end of the reflective film, but in Examples 3 to 12, wrinkles were not observed at the upper end of the reflective film.

[0451] Furthermore, in Examples 1 to 3 and 9, wrinkles were observed at the corners of the cut portion, but in Examples 4 to 8 and 10 to 12, wrinkles were not observed at the corners because the minimum radius of curvature of the cut portion was larger.

[0452] As can be seen from Example 6, wrinkles can be suppressed even when a heat-sealing layer is present.

[0453] As can be seen from Example 8, wrinkles can be suppressed even when the reflective layer is a dielectric multilayer film.

[0454] In Examples 10-12, because the minimum radius of curvature of the cut is too large, it is easy to visually identify the boundary between the part with the reflective film and the part without the reflective film based on the cut. In contrast, in Examples 1-9, because the minimum radius of curvature of the cut is not large, it is not easy to visually identify the boundary based on the cut.

[0455] Based on the above results, the effects of the present invention are clear.

[0456] Industrial availability

[0457] It can be appropriately used in vehicle head-up display (HUD) systems, etc.

[0458] Symbol Explanation

[0459] 10-Reflective film, 11-Cut-out portion, 12-Reflective layer, 14-Support body, 20-Head-up display system (HUD), 22-Projector, 24-Laminated glass (windshield), 25, 30a-Surface, 28-First glass plate, 30-Second glass plate, 36-Intermediate film, 38-Adhesive layer, D1-Depth, R-Radius of curvature, L1-Distance, D-Driver (user), Y-Up / Down direction.

Claims

1. A reflective film having wavelength-selective reflectivity, The average heat shrinkage rate when held at 140°C for 30 minutes is greater than 0.5% and less than 2.5%. The reflective film has a cutout on one edge, or on each of two opposing edges, or on each of four edges. The cut portion has a curved portion. The minimum radius of curvature of the curved portion is 100 mm or more and 900 mm or less.

2. The reflective film according to claim 1, wherein, The reflective film has a plurality of the cutouts.

3. The reflective film according to claim 1, wherein, The minimum radius of curvature of the curved portion is 100 mm or more and 700 mm or less.

4. The reflective film according to claim 1, wherein, The minimum radius of curvature of the curved portion is 100 mm or more and 500 mm or less.

5. The reflective film according to claim 1, wherein, The minimum radius of curvature of the curved portion is 100 mm or more and 300 mm or less.

6. The reflective film according to claim 1 or 2, wherein, The depth D1 of the cut is 10mm to 250mm.

7. The reflective film according to claim 1, having a substrate and a reflective layer disposed on a main surface side of the substrate.

8. The reflective film according to claim 7, wherein, The reflective layer is a cholesterol-type liquid crystal layer.

9. The reflective film according to claim 7 or 8, wherein, The selected reflection center wavelength of the reflective layer exists within the wavelength range of visible to infrared light.

10. The reflective film according to claim 9, wherein, The selective reflection center wavelength of the reflective layer exists in the visible light spectrum.

11. The reflective film according to claim 7, wherein, The reflective layer is a cholesteric liquid crystal layer consisting of two or more layers with different reflective center wavelengths.

12. A method for manufacturing laminated glass, wherein, A reflective film as described in any one of claims 1 to 11 is disposed between two glass plates, and the two glass plates are subjected to a heat-pressing process to manufacture laminated glass.

13. The method for manufacturing laminated glass according to claim 12, wherein, The reflective film is placed within 100mm of the end edge of the glass plate to perform the heat pressing process.

14. The method for manufacturing laminated glass according to claim 12 or 13, wherein, The maximum bending depth of the two glass plates is 15 mm or more.

15. A laminated glass having two glass plates and a reflective film disposed between the two glass plates, The reflective film has wavelength-selective reflectivity and an average thermal shrinkage rate of more than 0.5% and less than 2.5% when maintained at 140°C for 30 minutes. The reflective film has a cutout on one edge, or on each of two opposing edges, or on each of four edges. The cut portion has a curved portion. The minimum radius of curvature of the curved portion is 100 mm or more and 900 mm or less.

16. The laminated glass according to claim 15, wherein, The maximum bending depth of the two glass plates is 15 mm or more.

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