Method for producing laminated glass, functional film, and laminated glass

Abstract

To provide a method for producing laminated glass that is suitable for protecting a functional layer from degradation factors.SOLUTION: A method for producing laminated glass includes the preparation of: a functional film comprising a substrate, a protective layer, a functional layer and an adhesive layer, laminated sequentially; and a glass plate α and a glass plate β. This method then includes: bringing the adhesive layer into contact with the glass plate α to bond the functional film to the glass plate α; removing the substrate from the functional film to expose the protective layer; providing a resin interlayer so as to cover the protective layer; and bonding the glass plate β with the resin interlayer to produce the laminated glass.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for producing laminated glass, a functional film, and laminated glass. [Background technology]

[0002] In recent years, there has been an increase in the development of automobiles that are equipped with a head-up display (hereinafter referred to as HUD). HUD is a technology that projects images onto a transparent plate such as the windshield or combiner of an automobile, and allows the driver to recognize a virtual image formed on the plate, allowing the driver to obtain information about the automobile without moving their eyes much while driving. Currently, there are two main types: a type that uses a wedge-shaped transparent plate, and a type that projects polarized images onto a transparent plate. The latter type often has a functional layer inside the transparent plate that controls the behavior of polarized light.

[0003] Patent Document 1 describes an optical film that includes (A) an optical functional layer and (B) a blocking layer as an optical film that can be used as a functional layer. The (B) blocking layer is a cured product of a resin composition that includes (B-1) a thermoplastic resin and (B-2) an ultraviolet curable resin. It is said that by providing the (B) blocking layer, the retardation element provided as the (A) optical functional layer can be protected from degradation factors.

[0004] Furthermore, in order to provide an automobile windshield with a heat ray reflecting function, Patent Documents 2 and 3 disclose a method in which a functional film such as a heat ray reflecting film is sandwiched between two interlayer films and then sandwiched in a laminated glass. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 039394 [Patent Document 2] Patent Publication No. 2009-035439 [Patent Document 3] Patent Publication No. 2009-035440 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the optical film 10 is sandwiched between two interlayer films 201, and the deterioration factor is the plasticizer contained in the interlayer film for laminated glass. Therefore, in order to protect the optical functional layer from the deterioration factor, it was necessary to protect both sides of the optical functional layer by providing a blocking layer on both sides of the optical functional layer, or by having a blocking layer 102 on one side and the other side serving as a supporting substrate.

[0007] Furthermore, in Patent Documents 2 and 3, there was also the possibility that the heat ray reflective film would deteriorate due to the plasticizer in the interlayer.

[0008] The present disclosure has been made to address the above problems, and has an object to provide a method for manufacturing laminated glass suitable for protecting a functional layer from deterioration factors. [Means for solving the problem]

[0009] As a result of extensive research, the inventors have discovered that, rather than providing an interlayer film on both sides of the functional layer, the functional layer can be protected by attaching one side of the functional layer to glass, so that the contact surface between the functional layer and the interlayer film is only the side opposite the glass attachment surface, and by providing a protective film thereon. This discovery has led to the completion of the present disclosure.

[0010] The present disclosure is as follows.

[0011] The present disclosure (1) is a method for producing laminated glass, comprising the steps of preparing a functional film having a substrate, a protective layer, a functional layer, and an adhesive layer laminated in this order, glass plate α, and glass plate β, bringing the adhesive layer into contact with the glass plate α to bond the functional film to the glass plate α, removing the substrate from the functional film to expose the protective layer, providing a resin interlayer so as to cover the protective layer, and bonding the glass plate β with the resin interlayer to produce laminated glass.

[0012] The present disclosure (2) is the method for producing a laminated glass according to (1), wherein the functional layer is a retardation layer, a polarizing reflective layer, an infrared reflective layer, an infrared absorbing layer, or a visible light absorbing layer.

[0013] The present disclosure (3) is the method for producing a laminated glass according to (1) or (2), wherein the functional layer is an optical functional layer containing a liquid crystal material.

[0014] The present disclosure (4) is a method for producing laminated glass according to (3), wherein the liquid crystal material is a nematic liquid crystal.

[0015] The present disclosure (5) is the method for producing laminated glass according to any one of (1) to (4), wherein the protective layer is a curable resin layer, a thermoplastic resin layer, or an inorganic material layer.

[0016] The present disclosure (6) is the method for producing laminated glass according to (5), wherein the curable resin layer is at least one selected from the group consisting of an epoxy resin, a urethane resin, and a polyene polythiol resin.

[0017] The present disclosure (7) is the method for producing laminated glass according to (5) or (6), wherein the thermoplastic resin layer is at least one selected from the group consisting of a (meth)acrylic resin, polyethylene terephthalate, and triacetyl cellulose.

[0018] The present disclosure (8) is the method for producing a laminated glass according to any one of (1) to (7), wherein the total thickness of the protective layer, the functional layer and the adhesive layer is 35 μm or less.

[0019] The present disclosure (9) is the method for producing laminated glass according to any one of (1) to (8), in which the functional film is attached to only a part of the surface of the glass plate α.

[0020] The present disclosure (10) is the method for producing a laminated glass according to any one of (1) to (9), wherein the adhesive layer has a thickness of 100 μm or less.

[0021] The present disclosure (11) is the method for producing laminated glass according to any one of (1) to (10), in which the adhesive layer does not contain a plasticizer.

[0022] The present disclosure (12) is a method for producing a laminated glass according to any one of (1) to (11), in which the resin interlayer film contains 20% by weight or more of a plasticizer.

[0023] The present disclosure (13) relates to the method for producing a laminated glass according to any one of (1) to (12), in which the glass plate α and the glass plate β are curved.

[0024] The present disclosure (14) is a functional film in which a substrate, a protective layer, and a functional layer are laminated in this order.

[0025] The present disclosure (15) is the functional film according to (14), further comprising an adhesive layer provided on the functional layer.

[0026] The present disclosure (16) is the functional film according to (15), in which the adhesive layer does not contain a plasticizer.

[0027] The present disclosure (17) is a laminated glass comprising a glass plate α, a glass plate β, a functional film attached to a surface of the glass plate α facing the glass plate β, and a resin interlayer between the glass plate α and the glass plate β, wherein the functional film is formed by laminating an adhesive layer, a functional layer, and a protective layer in this order, the adhesive layer is attached to the glass plate α, and a main surface of the protective layer is covered with the resin interlayer.

[0028] The present disclosure (18) is a method for producing laminated glass, comprising the steps of preparing a functional film having a substrate, a functional layer, and an adhesive layer laminated in this order, glass plate α, and glass plate β, bringing the adhesive layer into contact with the glass plate α to attach the functional film to the glass plate α, removing the substrate from the functional film to expose the functional layer, forming a protective layer on the functional layer, providing a resin interlayer so as to cover the protective layer, and bonding the glass plate β with the resin interlayer to produce laminated glass. Effect of the Invention

[0029] The present disclosure can provide a method for producing laminated glass suitable for protecting a functional layer from deterioration factors. [Brief description of the drawings]

[0030] [Figure 1] 1A, 1B, 1C, 1D, and 1E are process diagrams that typically show one example of the steps of the method for producing laminated glass according to the present disclosure. [Diagram 2] FIG. 2 is a graph showing the relationship between the total thickness of the protective layer, the functional layer, and the adhesive layer and the perspective distortion. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates a schematic example of the configuration of a head-up display device including the laminated glass of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic configuration of another example of a head-up display device including the laminated glass of the present disclosure. [Diagram 5] 5A, 5B, 5C, 5D, and 5E are process diagrams that typically show one example of the steps of the method for producing laminated glass according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] A manufacturing method for laminated glass, a functional film, and laminated glass according to an embodiment of the present disclosure will be described with reference to the drawings. A head-up display device using the above laminated glass will also be described with reference to the drawings.

[0032] [First embodiment of the method for producing laminated glass according to the present disclosure] Two embodiments of the method for producing the laminated glass of the present disclosure are described herein. A first aspect of the method for producing laminated glass according to the present disclosure is a method for producing laminated glass, comprising the steps of preparing a functional film having a substrate, a protective layer, a functional layer, and an adhesive layer laminated in this order, a glass plate α, and a glass plate β, bringing the adhesive layer into contact with the glass plate α to attach the functional film to the glass plate α, removing the substrate from the functional film to expose the protective layer, providing a resin interlayer so as to cover the protective layer, and bonding the glass plate β with the resin interlayer to produce laminated glass. Hereinafter, a first embodiment of the method for producing laminated glass according to the present disclosure will be described. In the following description, when the method for producing laminated glass according to the present disclosure is simply mentioned, it means the first embodiment of the method for producing laminated glass according to the present disclosure.

[0033] 1A, 1B, 1C, 1D, and 1E are process diagrams that typically show one example of the steps of the method for producing laminated glass according to the present disclosure.

[0034] The functional film used in the method for producing laminated glass according to the present disclosure will now be described. An example of a procedure for preparing a functional film is shown in Figures 1A and 1B. Figure 1A shows a functional film 1a in which a substrate 90, a protective layer 60, and a functional layer 50 are laminated, and Figure 1B shows a functional film 1b in which an adhesive layer 40 is formed on the functional layer 50 of the functional film 1a.

[0035] In the method for producing laminated glass of the present disclosure, a functional film (functional film 1b shown in FIG. 1B) is prepared in which a substrate, a protective layer, a functional layer, and an adhesive layer are laminated in this order.

[0036] Examples of the substrate include (meth)acrylic resin (PMMA), polyethylene (PE), polypropylene (PP), triacetyl cellulose (TAC), polycarbonate, polyarylate, polyethersulfone, cycloolefin polymer, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). The substrate may be a transparent sheet or a non-transparent sheet.

[0037] The substrate preferably has a certain thickness to stabilize the workability of attaching the functional film to the glass plate, and the thickness of the substrate is more preferably 40 μm or more, and further preferably 60 μm or more, whereas the thickness of the substrate may be 200 μm or less. When a functional film is provided on a part of the laminated glass, the total thickness of the substrate, protective layer, functional layer, and adhesive layer becomes large, and therefore, if the laminated glass is produced with the substrate left, the perspective distortion at the contour of the functional film becomes large. In particular, when the substrate has a thickness of 40 μm or more, it is preferable to remove the substrate before producing the laminated glass, as in the first embodiment of the method for producing the laminated glass of the present disclosure.

[0038] The protective layer has a role of protecting the functional layer from the plasticizer in the interlayer, and is a layer that is difficult for the plasticizer to permeate. The protective layer may be a curable resin layer, a thermoplastic resin layer, or an inorganic material layer. When the protective layer is a curable resin layer, examples of the resin include silicone resin, acrylic resin, fluororesin, epoxy resin, urethane resin, and polyene polythiol resin, and it is preferable that the resin is at least one selected from the group consisting of epoxy resin, urethane resin, and polyene polythiol resin. The curability of the curable resin layer may be UV curability, heat curability, moisture curability, etc. The curable resin may have a plurality of these curability properties. When the protective layer is a thermoplastic resin layer, it is preferable that the thermoplastic resin layer is at least one selected from the group consisting of (meth)acrylic resin (PMMA), polyethylene (PE), polypropylene (PP), triacetyl cellulose (TAC), polycarbonate, polyarylate, polyethersulfone, cycloolefin polymer, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). The protective layer made of these resin materials can be formed by applying a resin solution containing the resin material to the substrate and curing it as necessary.

[0039] When the protective layer is a resin layer, it is preferable that the resin layer has a high crosslink density. If the crosslink density of the resin layer serving as the protective layer is high, the plasticizer contained in the interlayer film is less likely to permeate the protective layer, and the effect of providing the protective layer is more effectively exhibited. The crosslink density of the resin layer is 5.00×10 -4 [mol / cm 3 ] or more, and 2.00 × 10 -3 [mol / cm 3 ] or more is more preferable. -1 [mol / cm 3 ] or less.

[0040] When the protective layer is a resin layer, the resin preferably has a high glass transition temperature. The glass transition temperature of the resin is preferably 20° C. or higher, more preferably 90° C. or higher. Alternatively, the glass transition temperature may be 200° C. or lower.

[0041] When the protective layer is an inorganic material layer, examples of the protective layer include films of metals, metal oxides, metal nitrides, etc. Examples of metals include ZnAl, Ti, NiCr, Nb, stainless steel, etc. Examples of metal oxides include silica, alumina, titania, zinc oxide, indium tin oxide, etc. Examples of metal nitrides include silicon nitride, aluminum nitride, titanium nitride, etc. Protective layers made of these inorganic material layers can be formed by methods such as sputtering and wet coating.

[0042] The protective layer may be a film or sheet, and may be formed by laminating the protective layer on the substrate, or may be a film in which the substrate and the protective layer are integrated. The material of the film or sheet may be the curable resin or thermoplastic resin listed as the material of the protective layer, or the resin listed as the material of the substrate. In addition, since the refractive index of acrylic resin is close to that of glass, and epoxy resin has high protective performance, it is preferable to use a film having a laminated structure of acrylic resin and epoxy resin.

[0043] The thickness of the protective layer is preferably 2 to 30 μm, and more preferably 3 to 20 μm. If the thickness of the protective layer is 2 μm or more, the permeation of the plasticizer can be sufficiently prevented. On the other hand, even if the protective layer is made too thick, the ability to prevent the permeation of the plasticizer is not improved and it may cause light distortion, so the thickness of the protective layer is preferably 30 μm or less.

[0044] In addition, a release layer may be provided between the substrate and the protective layer so that the substrate can be easily peeled off when the substrate is removed. For example, the surface of the substrate may be treated with a silicone resin, a fluororesin, an acrylic resin, a cellulose resin, or the like.

[0045] After forming a protective layer on the substrate, a functional layer is formed on the protective layer. The functional layer is preferably a layer having at least one of the following functions (A) to (D). (A) Changing the phase or vibration direction of light (B) Transmit and / or reflect light with a specific vibration or rotation direction contained in the light (C) Absorb, transmit and / or reflect infrared rays contained in light (D) Absorb or reflect visible light contained in light

[0046] When the functional layer has the function of changing the phase or vibration direction of the light (A), the functional layer is, for example, a retardation layer (1 / 2λ layer, 1 / 4λ layer, etc.), and the functional film is a retardation film. A liquid crystal layer containing a liquid crystal material can be used as the retardation layer. A retardation layer can be formed by applying a liquid crystal material to a substrate film such as a transparent plastic sheet of orientation-treated polyethylene terephthalate (PET) or triacetyl cellulose (TAC), and then fixing the liquid crystal orientation by heat treatment or light treatment. The alignment film formed on the substrate for alignment treatment can be formed by applying and drying polyimide or polyvinyl alcohol, and then rubbing in one direction with a nylon cloth (rubbing), or by applying and drying a photo-alignment material, and then irradiating it with polarized light. As a method of alignment without using an alignment film, the substrate surface can be directly rubbed, or the aligned liquid crystal can be irradiated with polarized light. A protective layer formed on the substrate can also be rubbed or the like to be used as an alignment film for the liquid crystal material. Examples of liquid crystal materials include main-chain liquid crystal polymers such as polyester, polyamide, and polyesterimide, side-chain liquid crystal polymers such as polyacrylate, polymethacrylate, polymalonate, and polyether, and polymerizable liquid crystals. Polymerizable liquid crystals are liquid crystal materials that have a polymerizable group in the molecule. As the retardation layer, a retardation film obtained by uniaxially or biaxially stretching a plastic film such as polycarbonate, polyarylate, polyethersulfone, or cycloolefin polymer can also be used.

[0047] When the functional layer has the function of transmitting and / or reflecting light of a specific vibration direction or rotation direction contained in the light (B), the functional layer is, for example, a polarizing layer, a polarizing reflective layer, etc., and the functional film is a polarizing film or a polarizing reflective film. The polarizing layer can be a PVA (polyvinyl alcohol) layer containing iodine compound molecules. The polarizing layer can be made by adsorbing iodine compound molecules to PVA (polyvinyl alcohol) and stretching it so that the iodine compound molecules are oriented in one direction. The above PVA layer is laminated on a base film to form a polarizing film. The polarizing reflective layer may be a liquid crystal layer containing cholesteric liquid crystal. Furthermore, liquid crystal layers containing liquid crystal materials may be provided before and after the liquid crystal layer as 1 / 4 λ layers. The polarizing reflective film may be a substrate film having cholesteric liquid crystal fixed on its surface.

[0048] When the functional layer has the function of absorbing, transmitting and / or reflecting the infrared rays contained in the light (C), the functional layer is, for example, an infrared absorbing layer or an infrared reflective layer, and the functional film is an infrared absorbing / reflective film. The infrared absorbing layer or the infrared reflective layer may be a resin layer containing a dye or pigment that absorbs and / or reflects infrared rays. The infrared absorbing / reflective film may be a film obtained by mixing the above-mentioned dye or pigment with a resin material, applying the mixture to a substrate film, and drying the mixture. Examples of the infrared reflective layer include a multilayer film formed by laminating two or more types of resin or dielectric thin films having different refractive indices, a laminate film of a liquid crystal layer having polarizing properties, and a metal film or a laminate film of metal films.

[0049] When the functional layer has a function of absorbing visible light contained in the light (D), the functional layer is, for example, a visible light absorbing layer, and the functional film is a visible light absorbing film. As the visible light absorbing layer, a resin layer containing a material that absorbs visible light, such as a dye, a pigment, or carbon black, can be used. As the visible light absorbing film, a film in which a material that absorbs visible light is mixed with a resin material constituting the functional layer, applied to a base film, and dried can be used. When the functional layer has a function of reflecting visible light contained in the light (D), the functional layer is, for example, a reflection-enhancing layer, and the functional film is a visible light reflecting film. The reflection-enhancing layer can be a resin layer containing a material that reflects visible light. The visible light reflective film can be made by mixing a material that reflects visible light with the resin material that constitutes the functional layer, and forming a thin film of a metal or metal compound on a base film. In addition, the reflection-enhancing layer can be a layer in which several hundred resin layers with different refractive indices (such as PET and PMMA) are alternately stacked, which reflects light due to the difference in refractive index between the resins.

[0050] Moreover, instead of the layer having at least one of the functions (A) to (D) above, an optical thin film having a light interference effect can be used as the functional layer. Furthermore, when the functional layer has a function other than that affecting light, such a function may include attenuation or amplification of sound or vibration (sound insulation / vibration control), light control by external stimuli (dimming), conductivity, low dielectric constant, fluorescence, hologram, design, etc.

[0051] The functional layer included in the functional film used in the manufacturing method for laminated glass according to the present disclosure is preferably a retardation layer, a polarizing reflective layer, an infrared reflective layer, an infrared absorbing layer, or a visible light absorbing layer. The functional layer may be an optical functional layer containing a liquid crystal material, or may be a layer not containing a liquid crystal material. Among these, a layer containing a liquid crystal material is preferable, and the liquid crystal material is not particularly limited to nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, discotic liquid crystal, etc., but is preferably nematic liquid crystal. Since nematic liquid crystal as a liquid crystal material is easily deteriorated by the plasticizer contained in the resin interlayer, it is particularly effective to protect the functional layer.

[0052] The thickness of the functional layer may be 7 μm or less, 6 μm or less, 5 μm or less, or 3 μm or less, and may be 0.5 μm or more, 1 μm or more, 3 μm or more, or 4 μm or more.

[0053] The adhesive layer is not particularly limited as long as it is adhered to a glass plate. For example, the adhesive layer is preferably a thermoplastic resin layer, a thermosetting resin layer, a UV-curable resin layer, a visible light-curable resin layer, or a moisture-curable resin layer. The adhesive layer may also be a pressure-sensitive adhesive layer.

[0054] When the adhesive layer is a thermoplastic resin layer, examples of the thermoplastic resin include polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), acrylic resin (PMMA), urethane resin, cycloolefin polymer (COP), etc. When the adhesive layer is a UV-curable resin layer or a visible light-curable resin layer, examples of the UV-curable resin or visible light-curable resin include acrylic resin, epoxy resin, etc. When the adhesive layer is a thermosetting resin layer, examples of the thermosetting resin include epoxy resin, melamine resin, polyurethane resin, phenolic resin, etc. When the adhesive layer is a moisture-curable resin layer, examples of the moisture-curable resin include silicone resin, urethane resin, epoxy resin, vinyl chloride resin, and vinyl acetate resin. Of these, polyvinyl butyral, which is a thermoplastic resin, is preferred.

[0055] In addition, when the adhesive layer is a thermoplastic resin layer, a thermosetting resin layer, a UV-curable resin layer, a visible light-curable resin layer, or a moisture-curable resin layer, it is preferable that the adhesive layer further contains a silane coupling agent. Examples of the silane coupling agent include a silane coupling agent having an amino group as a functional group (3-(2-aminoethylamino)-propyltrimethoxysilane, etc.), a silane coupling agent having a vinyl group as a functional group (7-octenyltrimethoxysilane, etc.), a silane coupling agent having an epoxy group as a functional group (8-glycidoxyoctyltrimethoxysilane, or X-12-984S manufactured by Shin-Etsu Chemical Co., Ltd., etc.), a silane coupling agent having a mercapto group as a functional group (X-12-1154 manufactured by Shin-Etsu Chemical Co., Ltd., etc.), and a silane coupling agent having an acid anhydride group as a functional group (3-trimethoxysilylpropylsuccinic anhydride, etc.).

[0056] When the adhesive layer is a pressure-sensitive adhesive layer, it is preferably formed by attaching a double-sided pressure-sensitive adhesive sheet or applying a pressure-sensitive adhesive. The double-sided pressure-sensitive adhesive sheet is obtained by sandwiching a pressure-sensitive adhesive between two substrates to form a double-sided pressure-sensitive adhesive sheet, and then peeling off the substrate. The substrate is preferably made of PET (polyethylene terephthalate), acrylic resin, etc. Examples of pressure-sensitive adhesives constituting the pressure-sensitive adhesive layer include acrylic resin, silicon resin, epoxy resin, rubber, etc., and it is particularly preferable to include acrylic resin, which is transparent and has high adhesive strength.

[0057] Furthermore, the resin that exhibits adhesive properties in the adhesive layer may be the same as or a different type from the resin that constitutes the resin interlayer. In other words, whether the adhesive layer is a thermoplastic resin layer, a thermosetting resin layer, a UV-curable resin layer, a visible light-curable resin layer, a moisture-curable resin layer, or a pressure-sensitive adhesive layer, the thermoplastic resin, the thermosetting resin, the UV-curable resin, the visible light-curable resin, or the moisture-curable resin contained in the adhesive layer, or the resin constituting the adhesive resin layer of the pressure-sensitive adhesive layer may be the same type as the resin constituting the resin intermediate film, or may be a different type.

[0058] The thickness of the adhesive layer is not particularly limited, but is preferably 100 μm or less, more preferably 20 μm or less, and may be 5 μm or more. The adhesive layer is a component distinct from the resin interlayer, and the thickness of the adhesive layer is thinner than the thickness of the resin interlayer. The adhesive layer can be formed by applying a resin solution containing an adhesive to the protective layer and drying it.

[0059] The adhesive layer preferably does not contain a plasticizer. If the adhesive layer contains a plasticizer, the content of the plasticizer is preferably 0.1% by weight or less based on the weight of the adhesive layer. Examples of plasticizers that are preferably not contained in the adhesive layer include plasticizers contained in polyvinyl butyral used as a resin intermediate film, such as triethylene glycol di(2-ethylhexanoate), triethylene glycol (2-ethylbutyrate), bis(2-ethylhexyl)adipate, dihexyl adipate, dioctyl adipate, diisononyl adipate, diisodecyl adipate, diisononyl phthalate, and tris(2-ethylhexyl)trimellitate.

[0060] The total thickness of the protective layer, functional layer and adhesive layer is preferably 35 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. However, it may be 5 μm or more. The total thickness of the protective layer, functional layer and adhesive layer affects the perspective distortion, which is a test method specified in JIS R 3212 (2021) "Test method for automotive safety glass." FIG. 2 is a graph showing the relationship between the total thickness of the protective layer, the functional layer, and the adhesive layer and the perspective distortion. The horizontal axis of Fig. 2 shows the total thickness of the protective layer, functional layer, and adhesive layer [total thickness: μm], and the vertical axis shows the perspective distortion [min]. The measurement positions are the boundaries between the protective layer, functional layer, and adhesive layer and the resin interlayer film, that is, the areas around the contours of the protective layer, functional layer, and adhesive layer, surrounded by dotted line S in Fig. 1E. The actual vehicle mounting angle θ was 30°. According to JIS R 3211 (2021) "Automotive safety glass," the maximum allowable value for perspective distortion is 2 minutes, so the area with a total thickness of 35 μm or less where the perspective distortion is 2 minutes or less is defined as the favorable area from the perspective of perspective distortion.

[0061] Next, a manufacturing process of the laminated glass using the above-mentioned functional film will be described. In the manufacture of laminated glass, two glass plates (glass plate α and glass plate β) are prepared. Of the two glass plates, the glass plate to which the functional film is attached is designated as glass plate α. As the material for the glass plate, in addition to soda-lime silicate glass as specified in ISO16293-1, glass having a known glass composition such as aluminosilicate glass, borosilicate glass, and non-alkali glass can be used. The thickness of each of the glass plates may be, for example, 0.4 mm to 3 mm.

[0062] In addition, the glass plate is preferably curved. It is preferable that the convex surface of the curved glass plate is the surface to which the functional film is attached, and that this surface is the inner surface of the laminated glass. The degree of curvature is defined as the depth of curvature in the short side direction of the curved glass, which is defined as "overhang" in JASO M501 (Japanese Automotive Standards Organization standard M501). Overhang is a quantification of the curvature of a glass sheet and is defined as the maximum amount of bending or the maximum distance of the sheet from a corresponding reference line, which is an imaginary line drawn along the center of the top and bottom edges of the sheet. The oval of the glass plate may be 1 mm or more, 3 mm or more, 5 mm or more, or 25 mm or less, 20 mm or less, or 15 mm or less.

[0063] FIG. 1C shows a glass plate α (20) having a third main surface 23 and a fourth main surface 24. The adhesive layer 40 is brought into contact with the glass plate α (20) to attach the functional film 1b to the glass plate α (20). The functional film 1b is attached to the third main surface 23 of the glass plate α (20).

[0064] It is preferable that the functional film is attached only to a part of the surface of the glass plate α. The functional film does not have to be provided over the entire surface of the laminated glass. When the functional film has a function acting on the projection light, the functional film needs to be provided in the area irradiated with the projection light, but does not have to be provided in areas other than the area irradiated with the projection light. Since the materials that make up the functional film are expensive, by not providing the functional film in areas other than the area where the projection light is irradiated, the cost of the laminated glass used in the head-up display device can be reduced.

[0065] Next, as shown in Fig. 1D, the substrate 90 is removed from the functional film 1b to expose the protective layer 60. Fig. 1D shows a functional film 1c in which the adhesive layer 40, the functional layer 50, and the protective layer 60 are laminated. Next, as shown in FIG. 1E, a resin interlayer 30 is provided so as to cover the protective layer 60, and a glass plate β (10) is bonded to the resin interlayer 30 to produce a laminated glass 100. The glass plate β ( 10 ) is a glass plate having a first main surface 11 and a second main surface 12 . The distance between the glass plate β (10) and the glass plate α (20) can be adjusted by the thickness of the resin interlayer, and may be, for example, 0.01 mm to 2.5 mm.

[0066] There is no particular limitation on the material used for the resin interlayer, so long as it can be bonded to glass sheets. For example, two glass sheets are laminated together by heating at a temperature at which the polymer constituting the resin interlayer softens. Examples of polymers that can be used include polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), acrylic resin (PMMA), urethane resin, polyethylene terephthalate (PET), and cycloolefin polymer (COP). It is also possible to use an adhesive or pressure-sensitive adhesive that hardens when exposed to moisture, ultraviolet light, etc. The resin intermediate film may be composed of a plurality of resin layers.

[0067] When the resin interlayer contains a plasticizer, the effect of the method for producing laminated glass of the present disclosure of protecting the functional layer from deterioration factors is suitably exhibited, so a resin interlayer containing a plasticizer can be used. Examples of the plasticizer include triethylene glycol di(2-ethylhexanoate), triethylene glycol (2-ethylbutyrate), bis(2-ethylhexyl) adipate, dihexyl adipate, dioctyl adipate, diisononyl adipate, diisodecyl adipate, diisononyl phthalate, and tris(2-ethylhexyl) trimellitate. When the resin interlayer film contains a plasticizer, the content of the plasticizer is preferably 20% by weight or more, and more preferably 50% by weight or less, based on the weight of the resin interlayer film. When manufacturing laminated glass, a resin interlayer is sandwiched between two curved pieces of glass and heated to combine them. For this reason, plasticizers are often added to the resin interlayer to increase its flexibility so that it can conform to the curved glass sheets.

[0068] In the manufacturing method of laminated glass according to the present disclosure described above, in the step of providing the resin interlayer, one of the main surfaces of the functional layer is protected by the glass plate α via the adhesive layer and is not exposed. In addition, the other of the main surfaces of the functional layer is protected by a protective layer and is not exposed. Therefore, the resin interlayer is provided in a state in which both sides of the functional layer are protected. Therefore, it is possible to manufacture laminated glass while protecting the functional layer from deterioration factors such as plasticizers contained in the resin interlayer.

[0069] In addition, in a first aspect of the method for producing laminated glass of the present disclosure, a functional film having an adhesive layer is attached to a glass plate. In this case, a process of forming another layer on the functional film in a state where the functional film is attached to the glass plate is not required. Since layer formation in a state where the functional film is attached to a glass plate is difficult in terms of process, the first aspect is advantageous in terms of process compared to the second aspect of the method for producing laminated glass described later. Furthermore, since it is also difficult to form another layer on a functional film attached to curved glass, the first aspect is advantageous in terms of process as a process to be performed on a curved glass plate.

[0070] In addition, when the protective layer is a film in which the substrate and the protective layer are integrated, the film in which the substrate and the protective layer are integrated is exposed by attaching the functional film to a glass plate, so that a resin intermediate film is provided so as to cover the film in which the substrate and the protective layer are integrated, without removing the substrate from the functional film.

[0071] [Functional film of the present disclosure] The functional film of the present disclosure is a functional film in which a substrate, a protective layer, and a functional layer are laminated in this order. This corresponds to the functional film 1a shown in FIG. 1A. Preferred aspects of the substrate, protective layer, and functional layer are the same as those described as the configuration of the functional film used in the manufacturing method for laminated glass of the present disclosure.

[0072] The functional film of the present disclosure may further include an adhesive layer provided on the functional layer, which corresponds to functional film 1b shown in FIG. A preferred embodiment of the adhesive layer is the same as the embodiment described as the configuration of the functional film used in the manufacturing method of laminated glass of the present disclosure.

[0073] The functional film of the present disclosure can be suitably used in the method for producing laminated glass of the present disclosure.

[0074] [Laminated Glass of the Present Disclosure] The laminated glass of the present disclosure is a laminated glass including a glass plate α, a glass plate β, a functional film attached to a surface of the glass plate α facing the glass plate β, and a resin interlayer film between the glass plate α and the glass plate β, wherein the functional film is formed by laminating an adhesive layer, a functional layer, and a protective layer in this order, the adhesive layer is attached to the glass plate α, and a main surface of the protective layer is covered with the resin interlayer film.

[0075] The laminated glass of the present disclosure corresponds to the laminated glass 100 shown in FIG. 1E. The laminated glass 100 shown in FIG. 1E is a laminated glass including a glass plate α (20), a glass plate β (10), a functional film 1c attached to a third main surface 23, which is the surface of the glass plate α (20) facing the glass plate β (10), and a resin interlayer 30 between the glass plates α (20) and β (10). The functional film 1c is formed by laminating an adhesive layer 40, a functional layer 50, and a protective layer 60 in this order, with the adhesive layer 40 attached to the glass plate α (20), and the main surface of the protective layer 60 covered with the resin interlayer 30.

[0076] In this laminated glass 100, one of the main surfaces of the functional layer 50 is protected by the glass plate α (20) via the adhesive layer 40 and is not exposed. The other of the main surfaces of the functional layer 50 is protected by a protective layer 60 and is not exposed. The functional layer 50 is protected from deterioration factors such as the plasticizer contained in the resin interlayer 30, resulting in a laminated glass in which deterioration of the functional layer 50 is prevented.

[0077] In the laminated glass of the present disclosure, when the protective layer is a thin film, the film may be attached to the glass plate α together with the adhesive layer and the functional layer and remain inside the laminated glass without being peeled off.

[0078] In order to improve the adhesion between the functional layer, the protective layer, and the intermediate film, the above-mentioned silane coupling agent may be applied between the protective layer and the intermediate film and / or between the protective layer and the functional layer, or an adhesive layer may be formed. For example, an acrylic or silicone adhesive may be used as the adhesive.

[0079] As an example of use of the laminated glass of the present disclosure, an example of use as laminated glass mounted on a moving body will be described.

[0080] The laminated glass of the present disclosure is a laminated glass to be mounted on a moving body, and it is preferred that a first main surface of the glass plate β is a surface exposed to the outside of the moving body, the first main surface being a convex surface and the second main surface being a concave curved surface, and that a fourth main surface of the glass plate α is a surface exposed to the inside of the moving body, the fourth main surface being a concave surface and the third main surface being a convex curved surface. The laminated glass of the present disclosure is preferably a laminated glass that constitutes a head-up display device.

[0081] Examples of mobile bodies on which the head-up display device is mounted include cars (passenger cars, trucks, buses, etc.), trains, steam trains, ships, airplanes, etc. Among these, passenger cars are preferable. In addition, examples of positions where head-up display devices are mounted in a moving body include the windshield (front glass) and the back window (rear glass) of a passenger vehicle. Hereinafter, a head-up display device used on the windshield of a passenger vehicle will be described as an example.

[0082] 3 is a cross-sectional view showing a schematic example of a configuration of a head-up display device including the laminated glass of the present disclosure. In the drawing of the head-up display device, P-polarized light is indicated by a double arrow symbol, and S-polarized light is indicated by a double circle symbol. When both symbols are attached to one optical path, it means that either P-polarized light or S-polarized light is acceptable.

[0083] 3 shows a head-up display device 130a. The head-up display device 130a is mounted on a moving body, and the laminated glass 100 constitutes a part of the head-up display device 130a.

[0084] The first main surface 11 of the glass plate β (10) of the laminated glass 100 is the surface exposed to the outside room 123 of the movable body, and the first main surface 11 is a convex surface and the second main surface 12 is a concave curved surface, and the fourth main surface 24 of the glass plate α (20) is the surface exposed to the inside room 122 of the movable body, and the fourth main surface 24 is a concave surface and the third main surface 23 is a convex curved surface.

[0085] In the head-up display device 130 a, projection light 137 is emitted from the image unit 131 . Here, a plane including three points, namely, light emitting point 132 of image section 131, reflection point 133 where projection light 137 is reflected by first main surface 11, and viewpoint 134 of viewer 135, is the plane of incidence. When the moving body is a vehicle, it is preferable that the video unit 131 is disposed on the dashboard of the vehicle or the like.

[0086] In the head-up display device 130a, the functional film 1c is provided on the third main surface 23. In addition, the adhesive layer 40 of the functional film 1c is adhered to the third main surface 23.

[0087] When the functional film 1c is provided on the third main surface 23, natural light from the outdoor side 123 of the mobile object reaches the functional film 1c through the resin interlayer 30. Since the resin interlayer 30 can absorb the ultraviolet light contained in the natural light, deterioration of the functional layer 50 due to the ultraviolet light can be prevented. To achieve this effect, it is preferable that the resin interlayer 30 contains an ultraviolet absorbing agent. Furthermore, when the functional film 1c is provided on the third main surface 23, the functional film 1c is adhered to the convex surface. Since the glass plate α (20) is transported on a conveyor with the convex surface facing up and the functional film 1c can be adhered thereto, the workability in the process of manufacturing the laminated glass is excellent.

[0088] The functional film 1c is provided on a part of the third main surface 23, and the part on which the functional film 1c is provided is the part on which the projection light 137 is incident. The functional layer 50 of the functional film 1c has a function of changing the characteristics of the light incident on the laminated glass. When the laminated glass of the present disclosure is used in a head-up display device, the functional layer is preferably a retardation layer, and the functional film is preferably a retardation film.

[0089] A head-up display device in which a retardation layer is provided as a functional layer will be described below.

[0090] When the projection light 137 is P-polarized, it can be used in a sunglasses mode in which a virtual image is observed through polarized sunglasses. First, the P-polarized projection light 137 emitted from the image unit 131 is irradiated onto the fourth main surface 24. The angle at this time is preferably close to Brewster's angle (for example, Brewster's angle -10° or more, Brewster's angle +10° or less, or 46° to 66° if the Brewster's angle is 56°). When the P-polarized light is irradiated onto the fourth main surface 24 at the Brewster angle, no reflection occurs at the fourth main surface 24, and the projection light 137 is incident on the laminated glass 100. When the P-polarized light incident on the laminated glass 100 is incident on the functional layer 50 of the functional film 1c, the vibration direction changes and it becomes S-polarized light. In the head-up display device 130a, it is sufficient that reflection occurs on any surface other than the fourth main surface 24, so it is possible to use a 1 / 2 wavelength film (half wavelength film), a 1 / 4 wavelength film, etc. as the functional film (phase difference film). The vibration direction of light after passing through a retardation film varies depending on the type of retardation film and the direction of the optical axis. For example, when a half-wavelength film is used as the retardation film, the vibration direction of the projection light incident on the projection surface is rotated by 2dθ when the angle between the vibration direction of the projection light and the optical axis of the retardation sheet is dθ. Next, when the projection light 137 reaches the first main surface 11, it is reflected to form a reflected image. At this time, S-polarized light is reflected as the reflected light, and the other light that is not reflected passes through the first main surface 11 and is emitted to the outside of the room. Next, the reflected image formed on the first principal surface 11 passes through the retardation film again and becomes P-polarized light. A viewer 135 views a virtual image 136 on an extension of an optical path 138 based on the reflected image on the first principal surface 11. Since this virtual image 136 is made of P-polarized light, the viewer 135 can view the virtual image 136 even through polarized sunglasses. In this case, the viewer observes a virtual image based on the reflected image formed on the first main surface 11 of the glass plate β (10).

[0091] Since the functional film 1c only needs to be provided in an area of ​​the head-up display device 130a where the projection light 137 is irradiated, the functional film 1c is provided in the area of ​​the head-up display device 130a where the projection light 137 is irradiated. Other areas where the projection light 137 is not irradiated can be areas where the functional film 1c is not formed.

[0092] Although the head-up display device has been described using an example of a P-HUD device that uses P-polarized light as incident light, it may be an S-HUD device that uses S-polarized light as incident light.

[0093] FIG. 4 is a cross-sectional view that illustrates a schematic configuration of another example of a head-up display device including the laminated glass of the present disclosure.

[0094] 4 shows a head-up display device 130b. The head-up display device 130b is mounted on a moving body, and the laminated glass 100 constitutes a part of the head-up display device 130b. A plane including three points, namely, a light emitting point 132 of an image section 131, a reflection point 133 where a projection light 137 is reflected by the fourth main surface 24, and a viewpoint 134 of a viewer 135, is the plane of incidence. When the projection light 137 is S-polarized light, first, the S-polarized projection light 137 emitted from the image unit 131 is irradiated onto the fourth main surface 24. The angle at this time is preferably close to the Brewster angle (for example, Brewster angle -10° or more, Brewster angle +10° or less, 46° to 66° if the Brewster angle is 56°). At this time, the S-polarized light is reflected as reflected light, forming a reflected image. In this case, the viewer observes a virtual image 136 based on the reflected image formed on the fourth main surface 24 of the glass plate α (20). The projection light 137 that has traveled through the laminated glass 100 changes its vibration direction when it is incident on the functional layer 50 of the functional film 1c. In the head-up display device 130b, since it is sufficient that no reflection occurs on any surface other than the fourth main surface 24, it is possible to use a 1 / 2 wavelength film (half wavelength film), a 1 / 4 wavelength film, etc. as the functional film (phase difference film). The vibration direction of light after passing through a retardation film varies depending on the type of retardation film and the direction of the optical axis. For example, when a half-wavelength film is used as the retardation film, the vibration direction of the projection light incident on the projection surface is rotated by 2dθ when the angle between the vibration direction of the projection light and the optical axis of the retardation sheet is dθ. S-polarized light passes through the retardation film and becomes P-polarized light. If P-polarized light is incident on first principal surface 11 at the Brewster angle, it is not reflected by first principal surface 11 and is transmitted toward the outside. This prevents ghost images from occurring due to reflection of projection light 137 incident on laminated glass 100 at first principal surface 11.

[0095] The area where the functional film is provided can be, for example, an area with a vertical dimension of 50 mm to 500 mm and a horizontal dimension of 50 mm to 900 mm. The combined vertical and horizontal dimensions of the area can be 50 mm long x 50 mm wide to 500 mm long x 900 mm wide.

[0096] The proportion of the area of ​​the laminated glass where the functional film is provided is preferably 1% or more, and is preferably 50% or less, further preferably 20% or less, and further preferably 10% or less.

[0097] [Second embodiment of the method for producing laminated glass according to the present disclosure] Next, a second embodiment of the method for producing laminated glass according to the present disclosure will be described. A second aspect of the method for producing laminated glass according to the present disclosure is a method for producing laminated glass, which includes preparing a functional film having a substrate, a functional layer, and an adhesive layer laminated in this order, as well as glass plates α and β, bringing the adhesive layer into contact with the glass plate α to attach the functional film to the glass plate α, removing the substrate from the functional film to expose the functional layer, forming a protective layer on the functional layer, providing a resin interlayer so as to cover the protective layer, and bonding the glass plate β with the resin interlayer to produce laminated glass.

[0098] 5A, 5B, 5C, 5D, and 5E are process diagrams that typically show one example of the steps of the method for producing laminated glass according to the present disclosure. An example of a procedure for preparing a functional film is shown in Fig. 5A, which shows a functional film 1d in which a substrate 90, a functional layer 50, and an adhesive layer 40 are laminated. Preferred aspects of the substrate, functional layer, and adhesive layer are the same as those described as the configuration of the functional film used in the first aspect of the method for producing laminated glass of the present disclosure.

[0099] FIG. 5B shows a state in which the adhesive layer 40 is brought into contact with the glass plate α (20) and the functional film 1d is attached to the glass plate α (20). The functional film 1d is attached to the third main surface 23 of the glass plate α (20). A preferred embodiment of the glass plate is the same as the embodiment described as the configuration of the glass plate used in the first embodiment of the method for producing laminated glass of the present disclosure.

[0100] Next, as shown in Fig. 5C, the substrate 90 is removed from the functional film 1d to expose the functional layer 50. Fig. 5C shows a functional film 1e in which the adhesive layer 40 and the functional layer 50 are laminated. Next, as shown in FIG. 5D, a protective layer 60 is formed on the functional layer 50. The protective layer can be formed by applying a resin solution containing the material of the protective layer to the functional layer and curing it as necessary. When the protective layer is a film, it can be formed by laminating it on the functional layer. When the protective layer is an inorganic material layer, it can also be formed by a film formation method such as sputtering. FIG. 5D shows a functional film 1c in which an adhesive layer 40, a functional layer 50, and a protective layer 60 are laminated. The state shown in FIG. 5D is the same as the state shown in FIG. 1D, in which a functional film 1c having an adhesive layer 40, a functional layer 50 and a protective layer 60 laminated thereon is attached to a glass plate α (20). A preferred embodiment of the protective layer is the same as the embodiment described as the configuration of the protective layer used in the first embodiment of the method for producing laminated glass of the present disclosure.

[0101] Next, as shown in FIG. 5E, a resin interlayer 30 is provided so as to cover the protective layer 60, and the glass plate β (10) is bonded to the resin interlayer 30 to produce a laminated glass 100. This step is similar to the step described above as shown in FIG. 1E. A preferred embodiment of the resin interlayer film is the same as the embodiment described as the configuration of the resin interlayer film used in the first embodiment of the method for producing laminated glass of the present disclosure.

[0102] In the second aspect of the manufacturing method for laminated glass of the present disclosure described above, in the step of providing the resin interlayer, one of the main surfaces of the functional layer is protected by the glass plate α via the adhesive layer and is not exposed. In addition, the other of the main surfaces of the functional layer is protected by a protective layer and is not exposed. Therefore, the resin interlayer is provided in a state in which both sides of the functional layer are protected. Therefore, it is possible to manufacture laminated glass by protecting the functional layer from deterioration factors such as plasticizers contained in the resin interlayer.

[0103] In a second aspect of the method for producing laminated glass according to the present disclosure, a functional film is used in which a substrate, a functional layer, and an adhesive layer are laminated in this order. Since such laminated functional films are available as existing products, the process has a high degree of freedom and can be carried out on a variety of functional films. EXAMPLES

[0104] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to such examples. The materials used in the examples and comparative examples are as follows. Silane coupling agent to be contained in the adhesive layer: Silane coupling agent having an amino group as a functional group Thermoplastic resin for adhesive layer: PVB [polymerization degree approx. 3500, acetalization degree 8±2mol%, solvent is IPA / water] + 1wt% silane coupling agent added Thermoplastic resin for the resin intermediate film: PVB [thickness 0.76 mm], containing approximately 40% by weight of triethylene glycol di(2-ethylhexanoate) as a plasticizer UV-curable resin that acts as a protective layer Epoxy resin 1: Tg 99℃, crosslink density 2.10×10 -3 [mol / cm 3 ] Epoxy resin 2: Tg 117.9℃, crosslink density 5.00×10 -3 [mol / cm 3 ] · Urethane resin Polyene polythiol resin: Tg 21.0℃, crosslink density 1.60×10 -3 [mol / cm 3 ]

[0105] Example 1 A functional film was prepared in which a liquid crystal layer (including nematic liquid crystal) with a thickness of 2 μm was provided as a functional layer (retardation layer) on a substrate (TAC film with a thickness of 65 μm), and cut to a size of 50 mm×50 mm. A thermoplastic resin (PVB: composition not including plasticizer) that would become an adhesive layer was applied onto the liquid crystal layer of the functional film to form an adhesive layer with a thickness of 10 μm. A glass plate of 150 mm×150 mm×2 mmt was heated in an oven (135 to 200° C.), and the above-mentioned functional film was adhered with the adhesive layer facing toward a central 50 mm×50 mm area of ​​the heated glass plate. After the glass plate was cooled to about room temperature, the substrate was peeled off, and only the adhesive layer and the retardation layer were transferred onto the glass plate, leaving the retardation layer exposed on the surface. Next, a UV-curable resin (epoxy resin 1) that would become a protective layer was applied to the retardation layer to a thickness of 10 μm. After application, the UV-curable resin was cured using a UV irradiation device. The total thickness of the protective layer, the retardation layer and the adhesive layer is 22 μm.

[0106] A resin interlayer was inserted, and another glass plate (150 mm×150 mm×2 mmt) was placed on top of it, followed by heating and pressing to produce laminated glass.

[0107] Example 2 Except for using a 10 μm-thick UV-curable resin (epoxy resin 2) as the protective layer, a laminated glass was produced in the same manner as in Example 1. The total thickness of the protective layer, retardation layer, and adhesive layer was 22 μm.

[0108] Example 3 Except for using a 13 μm-thick UV-curable resin (urethane resin) as the protective layer, a laminated glass was produced in the same manner as in Example 1. The total thickness of the protective layer, the retardation layer, and the adhesive layer was 25 μm.

[0109] Example 4 Except for using a 5 μm-thick UV-curable resin (polyene polythiol resin) as the protective layer, a laminated glass was produced in the same manner as in Example 1. The total thickness of the protective layer, retardation layer, and adhesive layer was 17 μm.

[0110] Example 5 A 12.5 μm-thick resin sheet (a laminated film of a first layer of acrylic adhesive, a second layer of acrylic epoxy (an epoxy resin having an acrylate structure) layer, and a third layer of acrylic adhesive) was used as a protective layer, and laminated on the retardation layer in the same manner as in Example 1. A laminated glass was produced in the same manner as in Example 1. The total thickness of the protective layer, the retardation layer, and the adhesive layer was 24.5 μm.

[0111] Comparative Example 1 A laminated glass was produced in the same manner as in Example 1, except that no protective layer was applied.

[0112] Comparative Example 2 The substrate was not peeled off in Comparative Example 1. That is, the adhesive layer, the retardation layer, and the substrate were laminated on the glass, and the total thickness thereof was 77 μm.

[0113] (Measurement of perspective distortion of contour area) In the region of the retardation layer outlined by the dotted line S in FIG. 1E, the perspective distortion was measured by the test method specified in JIS R 3212 (2021) "Test Method for Automotive Safety Glass". The actual vehicle mounting angle θ was 30°. As a result, the perspective distortion was 2 minutes or less in Examples 1 to 5 and Comparative Example 1, but exceeded 2 minutes in Comparative Example 2.

[0114] (Measurement of polarization conversion peak wavelength) The polarization conversion peak wavelength was measured using an ultraviolet-visible-near infrared spectrophotometer. To measure the polarization conversion peak wavelength, the light incident on the sample was passed through a linear polarizer to make it S-polarized, and the same polarizer was placed in front of the integrating sphere so that only S-polarized light was incident on the integrating sphere. In addition, the sample was tilted and light was incident on the sample at an incident angle of 56°, and the transmittance was measured. In this measurement system, S-polarized light incident on the sample is converted to P-polarized light when it passes through the retardation layer. Therefore, the light converted to P-polarized light is blocked by the polarizer placed in front of the integrating sphere so that only S-polarized light passes through. In other words, the transmittance decreases as the wavelength at which the proportion of S-polarized light converted to P-polarized light increases. In this measurement, the wavelength at which the transmittance was the lowest was taken as the polarization conversion peak wavelength.

[0115] (Heat resistance test) In order to confirm the effect of the protective layer in suppressing deterioration of the retardation layer, a heat resistance test was performed. The test conditions were 100°C and 1200h, and the shift amount of the polarization conversion peak wavelength before and after the test was evaluated. If the shift amount was smaller than that of Comparative Example 1, it was determined that the protective layer was effective.

[0116] The shift amounts of the polarization conversion peak wavelengths in the heat resistance tests for the respective examples and comparative examples described up to this point are summarized in Table 1.

[0117] [Table 1]

[0118] As shown in Table 1, in Examples 1 to 5, the shift amount of the polarization conversion peak wavelength was reduced compared to Comparative Example 1, and it was confirmed that the layers functioned as protective layers.

[0119] In addition, Example 5 used a sheet that was a laminate of acrylic resin and acrylic epoxy resin. The protective layer contained acrylic resin, which has a refractive index close to that of glass, and therefore had a good appearance. In addition, the protective layer contained epoxy resin, which reduced the amount of shift in the peak wavelength, and therefore was highly effective as a protective layer. [Explanation of symbols]

[0120] 1a, 1b, 1c, 1d, 1e Functional films 10 Glass plate β 11 First principal surface 12 Second principal surface 20 Glass plate α 23 Third principal surface 24 Fourth principal plane 30 Resin interlayer 40 Adhesive layer 50 Functional Layers 60 protective layer 90 Base material 100 Laminated Glass 122 Indoor side of a moving object 123 Outside the vehicle 130a, 130b Head-up display device 131 Video Section 132 Light Point 133 Reflection point 134 Viewpoints 135 Visionary 136 Virtual Image 137 Projection light 138 Light path

Claims

1. A functional film having a substrate, a protective layer, a functional layer, and an adhesive layer laminated in this order, a glass plate α, and a glass plate β are prepared; The adhesive layer is brought into contact with a glass plate α to attach the functional film to the glass plate α; removing the substrate from the functional film to expose the protective layer; A method for producing laminated glass, comprising providing a resin interlayer so as to cover the protective layer, and laminating a glass plate β with the resin interlayer to produce laminated glass.

2. The method for producing laminated glass according to claim 1 , wherein the functional layer is a retardation layer, a polarizing reflective layer, an infrared reflective layer, an infrared absorbing layer, or a visible light absorbing layer.

3. The method for producing laminated glass according to claim 1 , wherein the functional layer is an optical functional layer containing a liquid crystal material.

4. The method for producing laminated glass according to claim 3, wherein the liquid crystal material is a nematic liquid crystal.

5. The method for producing laminated glass according to claim 1 or 2, wherein the protective layer is a curable resin layer, a thermoplastic resin layer, or an inorganic material layer.

6. The method for producing laminated glass according to claim 5, wherein the curable resin layer is at least one selected from the group consisting of epoxy resins, urethane resins, and polyene polythiol resins.

7. The method for producing laminated glass according to claim 5, wherein the thermoplastic resin layer is at least one selected from the group consisting of a (meth)acrylic resin, polyethylene terephthalate, and triacetyl cellulose.

8. The method for producing laminated glass according to claim 1 or 2, wherein a total thickness of the protective layer, the functional layer and the adhesive layer is 35 µm or less.

9. The method for producing laminated glass according to claim 1 or 2, wherein the functional film is attached to only a part of a surface of the glass plate α.

10. The method for producing laminated glass according to claim 1 or 2, wherein the adhesive layer has a thickness of 100 µm or less.

11. The method for producing laminated glass according to claim 1 or 2, wherein the adhesive layer does not contain a plasticizer.

12. The method for producing laminated glass according to claim 1 or 2, wherein the resin interlayer film contains 20% by weight or more of a plasticizer.

13. The method for producing laminated glass according to claim 1 or 2, wherein the glass plate α and the glass plate β are curved.

14. A functional film in which a substrate, a protective layer, and a functional layer are laminated in this order.

15. The functional film according to claim 14 , further comprising an adhesive layer provided on the functional layer.

16. The functional film according to claim 15 , wherein the adhesive layer does not contain a plasticizer.

17. A laminated glass comprising a glass plate α, a glass plate β, a functional film attached to a surface of the glass plate α facing the glass plate β, and a resin interlayer film between the glass plate α and the glass plate β, the functional film is formed by laminating an adhesive layer, a functional layer, and a protective layer in this order, and the adhesive layer is attached to the glass plate α; A laminated glass, wherein a main surface of the protective layer is covered with the resin interlayer.

18. A functional film having a substrate, a functional layer, and an adhesive layer laminated in this order, a glass plate α, and a glass plate β are prepared; The adhesive layer is brought into contact with a glass plate α to attach the functional film to the glass plate α; removing the substrate from the functional film to expose a functional layer; forming a protective layer on the functional layer; A method for producing laminated glass, comprising providing a resin interlayer so as to cover the protective layer, and laminating a glass plate β with the resin interlayer to produce laminated glass.

Images