Laminate

Abstract

To provide a laminate having both of thermal barrier capability and good design.SOLUTION: A laminate comprises at least a glass plate or polycarbonate plate with a thickness of less than 10 mm, a reflective light control layer, and an absorptive light control layer. The laminate has a solar heat gain Tts of 30% or less and also has, in the range of 400-750 nm in wavelength, a band with a width of 100 nm or more such that an absolute value RA of difference in average reflectance (%) between the front and rear sides becomes 20 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate having both heat insulation properties and design properties, and the laminate is mainly used as a light control window in transportation facilities and buildings. [Background technology]

[0002] Dimming windows in transportation and buildings are required to have heat-shielding properties in order to improve air-conditioning efficiency and achieve energy savings while allowing outside light, particularly sunlight, to enter the room and ensure visibility. In particular, dimming windows used in sunroofs and rear windows of vehicles such as automobiles tend to be located close to the bodies of passengers, so they tend to require higher heat-shielding properties. To improve the heat-shielding properties of dimming windows, it has been disclosed that, for example, colored glass (Patent Document 1) or glass with a metal sputtering treatment applied to the surface (Patent Document 2) can be used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2007 / 049766 Pamphlet [Patent Document 2] Japanese Patent Application Publication No. 9-323374 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in both of the technologies of Patent Documents 1 and 2, a portion of the incident light is absorbed by the glass, which converts the light into thermal energy and turns it into radiant heat, resulting in insufficient heat-shielding properties. Furthermore, if a thicker metal sputtering treatment is applied to improve heat-shielding properties, the resulting laminate may have a dazzling, mirror-like appearance or may have uneven color depending on the viewing angle, impairing the design and making it unsuitable for applications where design is important. Therefore, an object of the present invention is to provide a laminate that combines heat-shielding properties and design properties. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention has the following configuration: A laminate comprising a glass plate or a polycarbonate plate having a thickness of at least 10 mm or less, a reflective photochromic layer, and an absorptive photochromic layer, wherein the solar heat gain coefficient T ts is 30% or less, and the absolute value of the difference in the average reflectance (%) of the front and back surfaces in the wavelength range of 400 to 750 nm, R A The laminate is characterized by having a band with a width of 100 nm or more, in which the value of the saturation is 20 or more. [Effects of the Invention]

[0006] According to the present invention, a laminate having both heat-shielding properties and design properties can be obtained, and the laminate can be suitably used mainly as a light-control window in transportation facilities and buildings. DETAILED DESCRIPTION OF THE INVENTION

[0007] The laminate of the present invention will be described in detail below. The laminate of the present invention comprises a glass plate or polycarbonate plate having a thickness of at least less than 10 mm, a reflective photochromic layer, and an absorptive photochromic layer. It is important that the thickness of the glass plate or polycarbonate plate is 10 mm or less. If the thickness of the glass plate or polycarbonate plate exceeds 10 mm, it becomes difficult to control the path of light in the thickness direction of the glass plate or polycarbonate plate, and the effect of the present invention of combining heat insulation and design properties may not be achieved. There is also the problem of unnecessary weight increase when used in photochromic windows for transportation or buildings. On the other hand, the lower limit of the thickness of the glass plate or polycarbonate plate is 0.1 mm from the viewpoint of ensuring strength when used in photochromic windows for transportation or buildings. Examples of glass that can be used include general float glass, tempered glass, and colored glass. Note that a glass plate refers to a plate-shaped member in which glass accounts for 90% to 100% by mass of all components, and this can be interpreted similarly for a polycarbonate plate.

[0008] A reflective photochromic layer is a layer that has the property of reflecting and bouncing back light incident on the layer. Here, the term "reflective photochromic layer" refers specifically to a layer in which a continuous section of 100 nm or more exists in which the reflectance is 10% or more in the wavelength range of 400 to 750 nm. (In determining whether or not a layer corresponds to a reflective photochromic layer, if the above requirements are met when light is irradiated from at least one side, it can be considered a reflective photochromic layer. This also applies to determining whether or not an absorptive photochromic layer, which will be described later, is included.) The presence or absence of this band is determined using reflectance measured every 1 nm using a spectrophotometer; details of the spectrophotometer measurement are given in the Examples. Note that components that can be suitably used as a reflective photochromic layer will be described later.

[0009] The absorptive photochromic layer is a layer that has the property of absorbing incident light and not transmitting it. In this context, it is particularly a layer that does not satisfy the properties of a reflective photochromic layer, and Visible light transmittance is less than 50% The layer having this band is called an absorptive photochromic layer. The presence or absence of this band is determined using the transmittance measured at 1 nm intervals using a spectrophotometer, and details of the measurement using the spectrophotometer are shown in the Examples. Note that members that can be suitably used as the absorptive photochromic layer will be described later.

[0010] From the viewpoint of improving the heat shielding property, the laminate of the present invention has a solar heat gain coefficient T ts It is important that the solar heat gain coefficient T is 30% or less. ts The solar heat gain coefficient T can be calculated using the method specified in ISO13837:2008 based on the transmittance and reflectance data obtained by measuring with a spectrophotometer, and details will be described later. ts When the solar radiation heat gain coefficient T ts is preferably T ts It is difficult to completely block the penetration of heat such as radiant heat, so T ts The lower limit is effectively 5%.

[0011] Solar heat gain rate T tsThe method for making the visible light reflectance of the reflective photochromic layer or the visible light absorbance of the absorptive photochromic layer may be 30% or less, but is not particularly limited thereto. Examples of such a method include a method in which both the reflective photochromic layer and the absorptive photochromic layer are provided, and a method in which the visible light reflectance of the reflective photochromic layer or the visible light absorbance of the absorptive photochromic layer is increased.

[0012] From the viewpoint of achieving both heat-shielding properties and designability, the laminate of the present invention has an absolute value R of the difference in average reflectance (%) between the front and back surfaces in the wavelength range of 400 to 750 nm. A It is important that the band has a width of 100 nm or more, where R is 20 or more. The presence or absence of the band is determined using the reflectance measured at 1 nm intervals using a spectrophotometer, and the detailed method is shown in the Examples. A If the film does not have a band width of 100 nm or more where R is 20 or more, the effect of the present invention, which is to control the reflection characteristics of visible light by optimizing the balance between reflection and absorption and to provide both heat insulation and design properties, may not be obtained. A is more preferably 30 or more, and even more preferably 40 or more. A Although there is no particular upper limit, in consideration of the theoretical reflection limit and absorption limit of the reflective photochromic layer and the absorptive photochromic layer, the upper limit is substantially 90. Visible light refers to light in the range of 400 to 750 nm, and will be interpreted similarly hereinafter unless otherwise specified.

[0013] The absolute value R of the difference in average reflectance (%) between the front and back surfaces in the wavelength range of 400 to 750 nm ATo achieve a band of 100 nm or more in which the ratio is 20 or more, the laminate of the present invention preferably comprises an absorptive photochromic layer and a reflective photochromic layer, and uses a film (hereinafter referred to as a multilayer film) composed of a total of 50 or more layers of two thermoplastic resins with different optical properties stacked alternately as the reflective photochromic layer. "Different optical properties" here refers to a difference in refractive index of 0.01 or more in two arbitrarily selected orthogonal directions within the plane of the layer and in the direction perpendicular to the plane. "Alternately stacked" refers to layers of different resins stacked in a regular arrangement in the thickness direction. For example, if each layer of two thermoplastic resins with different optical properties is represented as layer A and layer B, the layers are stacked as A(BA)n (n is a natural number). By alternately stacking resins with different optical properties in this way, and controlling the relationship between the difference in refractive index of each layer and the layer thickness, reflection based on the principle of interference reflection can be achieved in the wavelength range of 400 to 750 nm. Sufficient reflective performance can be easily achieved by stacking a total of 50 or more layers. On the other hand, the more layers there are, the easier it is to control the reflective performance and the reflected band, but at the same time, manufacturing costs increase, so the practical range is up to a total of 10,000 layers.

[0014] In the laminate of the present invention, it is preferable that the absorptive photochromic layer be a layer made of a colored acrylic resin, silicone resin, or polyvinyl butyral resin (hereinafter sometimes referred to as a colored adhesive layer) from the viewpoint of achieving both heat-shielding properties and designability of the laminate. Using these resins in the absorptive photochromic layer improves the dispersibility of the coloring component and adhesion to adjacent layers, even when the layer contains a large amount of coloring component that results in a visible light transmittance of less than 50%, making it easier to control the design. Known dyes and pigments can be used alone or in any combination as coloring components. Specific examples include quinone-based, cationic, cyanine-based, phthalocyanine-based, quinacridone-based, diaryl / triarylmethane-based, fulgide-based, azo-based, squarylium-based, oxonol-based, benzylidene-based, nitro-based, nitroso-based, thiazole-based, and indigoid-based dyes, as well as carbon black and inorganic white pigments (e.g., titanium oxide and zinc oxide). It is preferable to disperse these materials more uniformly in the layer from the viewpoint of reducing unevenness in transmitted light.

[0015] In the laminate of the present invention, it is preferable that a glass plate or a polycarbonate plate is placed on one side of the reflective dimming layer made of the multilayer structure film, and an absorptive dimming layer colored with any of the resins is placed on the opposite side, in order to achieve both heat insulation and design. In this case, it does not matter whether another layer exists between the glass plate or the polycarbonate plate and the reflective dimming layer, or between the reflective dimming layer and the absorptive dimming layer.

[0016] The thickness of the laminate of the present invention is preferably 30 mm or less, more preferably 20 mm or less. When the thickness of the laminate is 30 mm or less, it becomes easy to control the path of light in the thickness direction of the laminate, and the effect of the present invention of combining heat-shielding properties and design properties is improved.

[0017] The laminate of the present invention is formed by measuring the average reflectance of each band of 100 nm width for each of the front and back surfaces while moving the band in 1 nm increments in the wavelength range of 400 to 750 nm, and comparing the maximum values ​​of the average reflectance of the front and back surfaces. When the surface with the larger value is designated as surface A, the maximum value R of the average reflectance of surface A is calculated. MAX and the minimum average reflectance R MIN Difference R MAX -R MIN is preferably 10% or less. In this case, when determining surface A, the "100 nm wide band" may be different on both sides, and a 100 nm wide band where the average reflectance is maximum can be selected for each side. For example, if the 100 nm wide band where the average reflectance is maximum on one side is the 400 to 499 nm range, and the 100 nm wide band where the average reflectance is maximum on the other side is the 450 to 549 nm range, surface A can be determined by comparing the average reflectance in each band. Note that the measurements required to determine surface A can be performed using a spectrophotometer capable of measuring reflectance in 1 nm increments, and details are shown in the Examples. Note that if the maximum values ​​are the same on both sides, R MAX -R MIN Calculate the value and choose the surface A with the larger value.

[0018] R MAX -R MIN By keeping R at 10% or less, the phenomenon in which the color of surface A is observed to change depending on the viewing angle when light incident on surface A is viewed from the same side as the incident side (hereinafter, this phenomenon may be referred to as "color unevenness") is suppressed, and deterioration of the design can be reduced. MAX -R MIN is more preferably 8% or less, and even more preferably 5% or less. MAX -R MIN From the above viewpoint, the smaller the value, the more preferable it is, and there is no particular lower limit, but the lower limit is theoretically 0%.

[0019] R on surface A MAX -R MINThe means for achieving this to be 10% or less or within the above-mentioned preferred range include a method of using a multilayer film as a reflective photochromic layer, a method of melt extruding the multilayer film by controlling the temperature so that the melt viscosities of the two thermoplastic resins constituting the film are close to each other when forming the film, and a method of suppressing the degree of shear heat generation, which causes the resin temperature inside the extruder to be higher than the set temperature of the extruder, within a certain range, and the like, and these methods can be combined as appropriate.

[0020] In the laminate of the present invention, the standard deviation of reflectance in the wavelength range of 400 to 750 nm on surface A is preferably 10% or less. A standard deviation of 10% or less suppresses color unevenness and the phenomenon in which rainbow-colored rings are observed on surface A depending on the viewing angle when light incident on surface A is viewed from the same side as the incident side (hereinafter, this phenomenon may be referred to as "rainbow unevenness"). This reduces deterioration of design. From the above perspective, the standard deviation is more preferably 8% or less, and even more preferably 5% or less. The smaller the standard deviation, the better, so there are no particular restrictions, but from the perspective of feasibility, the lower limit is 1%. The standard deviation can be calculated from the reflectance measured with a spectrophotometer, and details are provided in the Examples.

[0021] The means for achieving a standard deviation of reflectance in the wavelength range of 400 to 750 nm on surface A of 10% or less or the above-mentioned preferred range is to MAX -R MIN The same methods as those for achieving the target of 10% or less can be used.

[0022] The laminate of the present invention has a relative average reflectance (%) in the visible light region of surface A of R r , the absolute average reflectance (%) in the visible light region at an angle of 20° is R a20 In this case, 100×R a20 / R r It is preferable that 100×R is 80 or less. a20 / R rBy keeping R at 80 or less, when light incident on surface A is viewed from the same side as the incident side, the phenomenon whereby surface A glare like a mirror or metal depending on the viewing angle (hereinafter, this phenomenon may be referred to as "glare") is suppressed, and deterioration of the design is mitigated. a20 / R r is more preferably 70 or less, and even more preferably 60 or less. The smaller this value is, the better, but from the viewpoint of feasibility, the lower limit is 30. a20 or R r can be measured using a spectrophotometer, the details of which are shown in the Examples.

[0023] 100×R a20 / R r In order to achieve a value of 80 or less, when a multilayer film is used as a reflective photochromic layer, the method of adding organic particles or inorganic particles that serve as a light-scattering component to at least one of the resins that make up the multilayer may be used, or a method of providing a layer with light-scattering properties between the reflective photochromic layer and the absorptive photochromic layer may be used in combination as appropriate.

[0024] The laminate of the present invention preferably has a visible light transmittance of 10% or less from the viewpoint of improving heat-shielding properties and design. From the above viewpoints, it is more preferably 5% or less, and even more preferably 2% or less. A visible light transmittance of 10% or less prevents light energy from entering the interior, thereby improving heat-shielding properties. Furthermore, the reduced amount of transmitted light reduces color unevenness of the laminate when sunlight is viewed through the laminate, improving design properties. There are no particular restrictions on the lower limit of visible light transmittance, but when used in light-control windows in transportation or buildings, the lower limit is 0.2% from the viewpoint of viewing sunlight through the laminate. Visible light transmittance can be measured using a spectrophotometer, and details are provided in the Examples.

[0025] Methods for making the visible light transmittance of the laminate 10% or less or within the above-mentioned preferred range include using a reflective photochromic layer with a higher visible light reflectance, or increasing the dispersibility or concentration of the coloring component contained in the absorptive photochromic layer.

[0026] In the laminate of the present invention, it is preferable that the visible light reflectance of the reflective photochromic layer is 30% or more, more preferably 50% or more, and the visible light transmittance of the absorptive photochromic layer is less than 50%, more preferably 40% or less, from the viewpoint of achieving both heat-shielding and design properties. By making the visible light reflectance of the reflective photochromic layer 30% or more, the reflective photochromic layer reflects more visible light, preventing light energy from penetrating inside, thereby improving heat-shielding properties. Furthermore, by making the visible light transmittance of the absorptive photochromic layer less than 50%, the absorptive photochromic layer absorbs visible light, reducing glare and improving design properties. For example, when the reflective photochromic layer is made of a multilayer film, a method for making the visible light reflectance of the reflective photochromic layer 30% or more or within the above-mentioned preferred range can be achieved by increasing the refractive index difference between the layers. A method for making the visible light transmittance of the absorptive photochromic layer less than 50% or within the above-mentioned preferred range can be achieved by increasing the dispersibility or concentration of the coloring component contained in the absorptive photochromic layer.

[0027] From the viewpoint of improving heat-shielding properties, the laminate of the present invention preferably has an average transmittance of 70% or less in the wavelength range of 850 to 1150 nm. More preferably, the average transmittance is 50% or less, and even more preferably 30% or less. Light in the wavelength range of 850 to 1150 nm includes so-called near-infrared light and has high energy. Therefore, by reducing the average transmittance in this range, the heat-shielding properties are improved. The average transmittance in the wavelength range of 850 to 1150 nm can be measured using a spectrophotometer, and details are shown in the Examples.

[0028] The means for achieving an average transmittance of 70% or less in the wavelength range of 850 to 1150 nm of the laminate include a method of expanding the reflection band so that the multilayer film reflects the wavelength range of 850 to 1150 nm when using the multilayer film as a reflective dimming layer, a method of laminating a multilayer film having a reflection band in the wavelength range of 850 to 1150 nm separately in addition to the reflective dimming layer, a method of incorporating a near-infrared absorbing component that absorbs near-infrared rays in the wavelength range of 850 to 1150 nm in addition to a coloring component into the absorptive dimming layer, etc. These methods can be used in combination as appropriate.

[0029] In the laminate of the present invention, the visible light absorptance of the reflective photochromic layer is preferably less than 5% from the viewpoint of achieving both heat-shielding properties and designability, and more preferably 3% or less. The visible light absorptance can be calculated by subtracting the visible light transmittance and visible light reflectance (details are described in the Examples) measured with a spectrophotometer from 100%. One way to achieve a visible light absorptance of the reflective photochromic layer of less than 5% is to use a multilayer film as the reflective photochromic layer, in which 50 or more layers of two types of thermoplastic resins with different optical properties are alternately laminated. These methods can also be used in combination as appropriate.

[0030] The laminate of the present invention preferably has an electromagnetic wave transmission loss of 1 dB or less at a frequency of 28 GHz, so that the laminate does not impair the function of communication devices when used as a light-control window in transportation or a building. The electromagnetic wave transmission loss at a frequency of 28 GHz can be measured in accordance with ASTM D4935.

[0031] One way to achieve an electromagnetic wave transmission loss of 1 dB or less at a frequency of 28 GHz is to use a multilayer film as a reflective photochromic layer, in which two types of thermoplastic resins with different optical properties are alternately laminated in 50 or more layers. Other methods include selecting a component with low electromagnetic wave absorption when a coloring component or near-infrared absorbing component is contained, or lowering the concentration of a component with high radio wave absorption (such as organic carbon particles or particles with a high complex dielectric constant).

[0032] The laminate of the present invention is preferably used as a light control window for transportation or buildings. Transportation refers to means of transportation such as aircraft, ships, automobiles, and railways. Among transportation windows, in automobiles, it is particularly preferable to use it in windows located in positions that are likely to be close to the bodies of passengers, such as sunroofs and rear windows, from the viewpoint of enhancing the heat-shielding effect felt by passengers. In recent years, roof windows called panoramic roofs, which are equipped with large, seamless windows extending from the front window to the roof and rear window, have been increasing, and it is also preferable to incorporate the laminate of the present invention as part of them.

[0033] Hereinafter, an example of a specific embodiment of the laminate of the present invention will be shown, but it should not be construed as being limited to this example.

[0034] First, an example will be described in which a multilayer film is used as the reflective photochromic layer of the present invention, which is composed of 50 or more layers of two types of thermoplastic resins with different optical properties laminated alternately. Each thermoplastic resin preferably comprises a polyester resin as its main component. Here, polyester resin refers to a polycondensate synthesized by dehydration condensation of a dicarboxylic acid and a diol to form an ester bond. "Comprised primarily of polyester resin" means that the total thermoplastic resin contains a polyester resin in a proportion of more than 50% by mass and not more than 100% by mass. The polyester resin constituting the multilayer film preferably comprises a polyester obtained by polymerization of a monomer primarily composed of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol. Note that "comprised primarily of aromatic dicarboxylic acid or aliphatic dicarboxylic acid" means that, when the total dicarboxylic acid units constituting the polyester resin are taken as 100 mol%, aromatic dicarboxylic acid units or aliphatic dicarboxylic acid units account for 80 mol% to 100 mol%.

[0035] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, and 4,4'-diphenylsulfonedicarboxylic acid. Examples of aliphatic dicarboxylic acids include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid, and their ester derivatives. Among these, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are particularly preferred. These acid components may be used alone or in combination.

[0036] Examples of diol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxyphenyl)propane, isosorbate, spiroglycol, etc. These diol components may be used alone or in combination of two or more.

[0037] The multilayer film preferably comprises two polyester resins with different optical properties, with one of the two polyester resins being a crystalline polyester and the other being an amorphous polyester. The term "amorphous polyester" refers to a polyester whose heat of crystalline fusion ΔHm, calculated from the peak area of ​​the melting peak, is 5 J / g or less in a differential scanning calorimetry chart obtained by heating the resin from 25°C to 300°C at a heating rate of 20°C / min (first run), holding the resin at that temperature for 5 minutes, then rapidly cooling it to 25°C or below, and then heating it again from room temperature to 300°C at a heating rate of 20°C / min (second run) according to JIS K 7122 (1999). The term "crystalline polyester" refers to a polyester whose heat of crystalline fusion ΔHm exceeds 5 J / g.

[0038] The crystalline polyester is preferably polyethylene terephthalate or polyethylene naphthalate from the viewpoint of suppressing the occurrence of color unevenness or iridescent unevenness due to resin degradation during production. Furthermore, the amorphous polyester is preferably polyethylene terephthalate or polyethylene naphthalate, and contains at least one of spiroglycol, cyclohexanedicarboxylic acid, and cyclohexanedimethanol as a copolymerization component, more preferably cyclohexanedimethanol. When cyclohexanedimethanol is contained, the copolymerization amount of cyclohexanedimethanol is preferably 15 mol % or more and 60 mol % or less, when the total diol units are taken as 100 mol %.

[0039] By selecting crystalline polyesters and amorphous polyesters in this way and laminating them alternately to form a film, a multilayer film can be obtained that has high reflectivity, has little fluctuation in optical properties that cause color unevenness and rainbow unevenness, and is less susceptible to peeling between layers. Note that the two types of polyester resin layers laminated alternately may be blended with multiple crystalline polyesters or may be blended with an amorphous polyester and a crystalline polyester in order to adjust the reflectivity of each layer.

[0040] The crystalline polyester and the amorphous polyester may contain various additives, such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and doping agents for adjusting the refractive index, within the range that does not impair the heat-shielding properties and design properties of the laminate of the present invention.

[0041] In particular, adding inorganic particles to the interior of a multilayer film is preferred from the perspective of reducing glare and enhancing design. The average particle size of the inorganic particles is preferably 0.05 μm or more and 1.00 μm or less to achieve an effective particle scattering effect. By setting the average particle size to 0.05 μm or more, more preferably 0.10 μm or more, and even more preferably 0.15 μm or more, effective particle scattering can be achieved while preventing aggregation through good dispersibility. Here, the average particle size refers to the number-average particle size. In terms of the overall effects of refractive index, whiteness, optical density, etc., titanium oxide, calcium carbonate, and barium sulfate are preferred as inorganic particle materials. The inorganic particles are preferably surface-treated to enhance light scattering at the interface with the thermoplastic resin. Examples of surface treatment agents that are preferred include silicone, silane coupling agents, aluminum chelating agents, and polyureas, with silane coupling agents being particularly preferred. The inorganic particles are preferably added to the layer containing amorphous polyester among the alternating resin layers of the multilayer film. The amount of addition is preferably 0.1 to 2.0% by mass of the total components constituting the layer to which it is added.

[0042] Multilayer films are manufactured by laminating thermoplastic resins, for example, using the following method. First, two types of thermoplastic resins are prepared in the form of pellets or the like. The pellets are dried in hot air or under vacuum, if necessary, and then fed into separate extruders. The thermoplastic resins are heated and melted in the extruders, and the extrusion rate is uniformed using a gear pump or the like, followed by removal of foreign matter and denatured resins through a filter or the like. Next, the two types of thermoplastic resins are fed into a multilayer lamination device through separate flow paths and alternately laminated. To prevent rainbow unevenness in the resulting laminate, the difference in viscosity between the two types of resins immediately before flowing into the multilayer lamination device is preferably 30 Pa·s or less, more preferably 15 Pa·s or less. Furthermore, to prevent rainbow unevenness in the laminate of the present invention, it is preferable that the deviation between the measured temperatures of the two types of thermoplastic resins immediately before flowing into the multilayer lamination device and the maximum set temperature of each extruder be within 10°C.

[0043] Multi-layer lamination devices such as multi-manifold dies, feed blocks, and static mixers can be used, but it is particularly preferable to use a feed block with 50 or more fine slits. Using such a feed block prevents the device from becoming excessively large, reduces the amount of foreign matter caused by thermal degradation, and enables high-precision lamination even when the number of layers is extremely large. Furthermore, the lamination precision in the width direction is significantly improved compared to other methods. Furthermore, the thickness of each layer can be adjusted by the shape (length and width) of the slits, making it easy to achieve any desired layer thickness.

[0044] The laminated molten resin is then formed into a sheet using a die and extruded onto a cooling body such as a casting drum to be cooled and solidified to obtain a cast film. In this case, it is preferable to use a wire-, tape-, needle-, or knife-shaped electrode to bring the molten resin sheet into close contact with the cooling body such as a casting drum by electrostatic force to rapidly cool and solidify it.

[0045] The cast film thus obtained is preferably biaxially stretched. Here, biaxial stretching refers to stretching in the longitudinal direction and the width direction, where the longitudinal direction refers to the running direction of the film and the width direction refers to the direction perpendicular to the longitudinal direction in the plane of the film. The stretching may be performed in two directions sequentially (sequential biaxial stretching) or in two directions simultaneously (simultaneous biaxial stretching), but sequential biaxial stretching is more preferred from the viewpoint of mass productivity.

[0046] In the case of sequential biaxial stretching, the longitudinal stretching speed is preferably 50 to 300% / sec, more preferably 70 to 200% / sec, from the viewpoint of suppressing iridescent unevenness in the laminate of the present invention. Generally, longitudinal stretching is performed by the difference in peripheral speed of the rolls, and the stretching ratio is preferably 2 to 5 times. From the viewpoint of achieving uniform in-plane stretching, the stretching temperature is preferably the average glass transition temperature of the two resins constituting the casting film to be stretched to the average glass transition temperature of the two resins + 50°C.

[0047] Subsequently, the uniaxially stretched film obtained by longitudinal stretching is preferably stretched in the width direction at a stretching speed of 5 to 40% / sec, more preferably 8 to 30% / sec, from the viewpoint of suppressing iridescent unevenness in the laminate of the present invention. Generally, the width direction stretching is performed using a tenter, conveying the film while holding both ends with clips, and the stretching ratio is preferably 2 to 6.5 times. More preferably, the width direction stretching ratio is 100 to 130% of the longitudinal direction stretching ratio, from the viewpoint of suppressing iridescent unevenness in the laminate of the present invention. From the viewpoint of achieving uniform in-plane stretching, the stretching temperature is preferably the average glass transition temperature of the two resins constituting the uniaxially stretched film to be stretched at a temperature equal to or higher than the average glass transition temperature of the two resins + 50°C.

[0048] The biaxially stretched film is preferably heat-treated in a tenter at a temperature between the width direction stretching temperature +100°C and the width direction stretching temperature +150°C to enhance the film's durability and to homogenize its in-plane physical properties. In this case, it is preferable to perform a relaxation treatment in the width direction at a relaxation rate of 0.01 to 1% / sec in the latter half of the heat treatment in order to control thermal shrinkage when the film is used at high temperatures. The relaxation ratio is preferably 0.9 to 0.99 times the film width immediately before relaxation. The film is then uniformly and gradually cooled to room temperature, after which both edge portions that were held by the tenter clips are cut and wound up.

[0049] Next, a polyvinyl butyral resin (PVB) sheet (colored adhesive layer) containing a coloring component and adjusted to a visible light transmittance of less than 50% and a polyvinyl butyral resin sheet (adhesive layer) containing no coloring component or containing a coloring component but having a visible light transmittance of more than 70% are prepared. The thickness of both the absorbent PVB sheet and the PVB sheet is preferably in the range of 3 μm to 1000 μm from the viewpoint of improving the adhesion of the interfaces of the layers constituting the laminate described below and enhancing the design.

[0050] The absorbent PVB sheet and the PVB sheet may contain various additives, such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and dopants for adjusting the refractive index, as long as the heat-shielding properties and design properties of the laminate of the present invention are not impaired.

[0051] From the viewpoint of achieving both heat insulation and design, the laminate of the present invention is preferably a glass plate or polycarbonate plate having a thickness of less than 10 mm, a reflective dimming layer, and an absorptive dimming layer, laminated in the order glass plate (or polycarbonate plate) / reflective dimming layer / absorptive dimming layer. One actually preferred configuration is a configuration (configuration α) in which the multilayer film described above is used as the reflective dimming layer and the colored adhesive layer described above is used as the absorptive dimming layer, and the laminate is laminated in the order glass plate 1 (or polycarbonate plate 1) / adhesive layer / multilayer film / colored adhesive layer / glass plate 2 (or polycarbonate plate 2). This configuration can increase the strength and durability when used as a dimming window.

[0052] Furthermore, a configuration (configuration β) in which high-strength tempered glass is used as the glass plate 1 and glass plate 2 is replaced with a resin film (such as a polyethylene terephthalate film) is also suitable for weight reduction and is preferably used.

[0053] In both of the structures α and β, it is preferable that the glass plate 1 (or polycarbonate plate 1) be installed so that it faces the side where a light source such as sunlight is incident. Furthermore, both of the structures α and β may include another light-controlling panel layer capable of electrically controlling the visible light transmittance. In this case, it is preferable that the light-controlling panel layer be inserted at a position farther from the side where the light source is incident than the multilayer film layer, in order to avoid impairing the heat-shielding properties and design properties of the laminate of the present invention. Furthermore, the front and back surfaces of the structures α and β may be subjected to surface treatments such as hard coating or water-repellent treatment, as long as the heat-shielding properties and design properties of the laminate of the present invention are not impaired. [Example]

[0054] The laminate of the present invention will be described in more detail below using examples, but the laminate of the present invention is not limited to these examples.

[0055] [Methods for measuring physical properties and evaluating effects] The evaluation methods for the characteristic values ​​and the effects are as follows.

[0056] A. Solar heat gain rate T ts (%) A 5cm x 5cm laminate was prepared as a measurement sample, and a Hitachi spectrophotometer (U-4100 Spectrophotometer) equipped with a 12° specular reflection attachment (P / N134-0104) was attached to measure the transmittance and reflectance at wavelengths of 250 to 2600nm at an incident angle of φ = 12°. The measurement conditions were a slit of 2nm (visible) / automatic control (infrared), a gain of 2, a scanning speed of 600nm / min, and output data was collected every 1nm. Based on the obtained transmittance and reflectance data, T was measured according to the method specified in ISO13837:2008. ts The measurements were carried out with the sample turned over, and T ts The value of the surface with the smaller value is the T of the sample. ts (%).

[0057] B. Absolute value R of the difference in average reflectance (%) between the front and back surfaces in the wavelength range of 400 to 750 nm A A 5 cm x 5 cm laminate was prepared as a measurement sample, and a Hitachi spectrophotometer (U-4100 Spectrophotometer) equipped with a 12° specular reflection attachment (P / N 134-0104) was attached to measure the reflectance at wavelengths of 400 to 750 nm at an incident angle φ of 12°. The measurement conditions were a slit of 2 nm, a gain of 2, and a scanning speed of 600 nm / min, with output data collected every 1 nm. Similar measurements were performed on the front and back of the sample. Next, the data for both the front and back were entered into spreadsheet software "Excel" (registered trademark) 2010 (Microsoft Corporation), and the average reflectance in the range of 400 to 499 nm (bandwidth 100 nm) was calculated for each front and back. The absolute value of the difference in the average reflectances of the front and back, R, was calculated. A was calculated. R A The calculation of R was carried out by shifting the averaging band by 1 nm toward the longer wavelength side until it reached the range of 651 to 750 nm. A The maximum value of the R AIn addition, the R obtained by this method A If the value is 20 or more, the sample has an absolute value R of the difference in the average reflectance (%) of the front and back in the wavelength range of 400 to 750 nm. A The band width was determined to be 100 nm or more, where the value of the band width was 20 or more.

[0058] CR MAX -R MIN In step B, based on the data entered into the spreadsheet software, the average reflectance of each band was calculated while moving a 100 nm wide band in 1 nm increments in the wavelength range of 400 to 750 nm. Similar calculations were performed on both the front and back of the sample. Next, the maximum value of the average reflectance on either the front or back of the sample was defined as r1, and the maximum value of the average reflectance on the other side was defined as r2. Comparing r1 and r2, the side with the larger value was defined as side A. Next, the maximum value of the data group of average reflectance on side A was defined as R MAX (%), minimum value R MIN (%), and the difference R MAX -R MIN (%) was calculated. When r1 = r2, R MAX -R MIN The surface with the largest value is defined as surface A, and the data of that surface is used as the R MAX -R MIN was adopted as.

[0059] D. Standard deviation of reflectance of surface A For surface A defined in C above, the standard deviation (%) was calculated using the STDEV.P function in the spreadsheet software "Excel" (registered trademark) 2010 (Microsoft Corporation) based on the reflectance data measured at 1 nm intervals in the wavelength range of 400 to 750 nm using the same method as in B and C above.

[0060] E.100×R a20 / R r For surface A defined in C above, the average value of the reflectance in the wavelength range of 400 to 750 nm was calculated based on the reflectance data measured at 1 nm intervals in the wavelength range of 400 to 750 nm using the same method as in B and C above, and the average relative reflectance in the visible light region was calculated as R r Next, an 8 cm x 8 cm laminate was prepared as a measurement sample, and an attached variable angle absolute reflectance device (20-60°) P / N134-0115 (revised) was installed in a Hitachi spectrophotometer (U-4100 Spectrophotometer), and absolute reflectance measurements were performed for P-wave and S-wave wavelengths of 400-750 nm at an incident angle of 20° and a reflection angle of 20° for surface A defined in C above. The measurement conditions were a slit of 2 nm, a gain of 2, a scanning speed of 600 nm / min, and output data was collected every 1 nm step. The average value of the P-wave and S-wave data for each wavelength was taken as the absolute reflectance at that wavelength. Next, the average absolute reflectance in the wavelength range of 400-750 nm was calculated, and the average absolute reflectance in the visible light region at an angle of 20° was determined as R a20 Finally, the R obtained above r and R a20 From the value of 100×R a20 / R r The value was calculated.

[0061] F. Visible light transmittance, average transmittance, visible light reflectance, visible light absorptance A 5cm x 5cm measurement sample was prepared, and a Hitachi spectrophotometer (U-4100 Spectrophotometer) equipped with a 12° specular reflection attachment (P / N 134-0104) was attached to measure the transmittance and reflectance at an incident angle of φ = 12° over a wavelength range of 250 to 2600 nm. The measurement conditions were a slit of 2 nm (visible) / automatic control (infrared), a gain of 2, and a scanning speed of 600 nm / min. Output data was collected every 1 nm. Next, the average value for a given wavelength range was calculated from the obtained transmittance or reflectance data, and this was taken as the average transmittance over that wavelength range. Visible light transmittance was defined as the average transmittance over a wavelength range of 400 to 750 nm. Similarly, visible light reflectance was defined as the average reflectance over a wavelength range of 400 to 750 nm. Visible light absorptance (%) was calculated by dividing the visible light transmittance of a sample by Tv (%), visible light reflectance R v (%), 100-T v -R v It was calculated as:

[0062] G. Electromagnetic wave transmission loss In accordance with ASTM D4935, the electromagnetic wave transmission loss (dB) at a frequency of 28 GHz was measured using a coaxial tube type shielding effectiveness measurement system from Keycom Corporation.

[0063] H. Heat insulation In a dark room at a room temperature of 25°C and a relative humidity of 50%, a solar simulator (SS-156XIL) manufactured by Eiko Seiki was used, with a spectral characteristic of AM1.5 and an illuminance of 100mW / cm. 2 A 20cm square laminate sample, whose surface temperature was kept at 25°C, was placed horizontally 20cm below the lamp light source. The sample was placed so that surface A, specified in C above, faced the lamp light source. Next, 20 minutes after placement, the surface temperature of the laminate opposite surface A was measured with a contact thermometer, and the heat shielding properties were evaluated according to the following criteria. [Heat-shielding performance criteria] A: The surface temperature was below 45°C. B: The surface temperature was 45°C or higher and less than 50°C. C: The surface temperature was 50°C or higher and less than 55°C. D: The surface temperature was 55°C or higher.

[0064] I. Design (color unevenness) Using a solar simulator operated under the same conditions as in H above, a 20 cm square laminate sample was placed 40 cm directly below the lamp light source so that the angle of incidence of the light source on the laminate surface (plane A defined in C above) was 45°. Next, 10 subjects placed their viewpoint at a position (reference point) where they could view the specularly reflected light of the lamp light from the laminate surface directly. They then varied the observation angle from that reference point and performed visual observations, evaluating color unevenness according to the following criteria. When varying the observation angle, the point of incidence of the light from the light source on the laminate surface was used as the axis of rotation, and the subject's viewpoint was varied within the plane connecting the light source, the incident point, and the reference point. The distance between the subject's viewpoint and the incident point was always 1 m. [Design (color unevenness) evaluation criteria] A: When the observation angle was changed by ±30° from the standard position, no subjects noticed a color change on the laminate surface. B: One to four subjects noticed a color change on the surface of the laminate while the observation angle was changed by ±30° from the reference position. C: Five to nine subjects noticed a color change on the surface of the laminate while the observation angle was changed by ±30° from the standard position. D: All 10 subjects noticed a color change on the surface of the laminate while changing the observation angle by ±30° from the reference position.

[0065] J. Design (Rainbow unevenness) A 50 cm square laminate sample was prepared, and sunlight was visually observed through the laminate while wearing polarized sunglasses that block S-polarized light, and the presence or absence of rainbow unevenness (rainbow-colored interference fringes) was judged according to the following criteria. Note that the observation was performed with the sunlight incident surface set to surface A specified in C above, and the angle of incidence and the angle of visual observation were changed in all directions. [Design (rainbow unevenness) evaluation criteria] A: No rainbow unevenness was observed at all.

[0066] B: Rainbow unevenness was observed that could be seen by staring.

[0067] C: Rainbow unevenness was observed, even without staring, depending on the observation angle.

[0068] D: Rainbow unevenness was observed regardless of the observation angle and could be seen without staring.

[0069] K. Design (Glare) A 50 cm square laminate sample was prepared, and sunlight was irradiated onto surface A defined in C above, and the reflected light from surface A was visually observed to determine the degree of glare. The observation was carried out while changing the angle of incidence of sunlight and the angle of visual observation in all directions, and the degree of glare was evaluated relative to the standard of the degree of glare of "LAMIPANE" windshield manufactured by Nippon Sheet Glass Co., Ltd. (hereinafter referred to as "standard glass"), and was determined according to the following criteria. [Design (glare) evaluation criteria] A: Glare was reduced compared to standard glass.

[0070] B: The glare was the same as that of the standard glass, or was slightly increased to the extent that it was noticeable when staring.

[0071] C: Glare increased to the extent that it was noticeable without staring at the glass compared to the standard glass.

[0072] D: Clearly strong glare was observed compared to standard glass.

[0073] [Resins used in the manufacture of multi-layer films and laminates] Resin 1: Polyethylene terephthalate with an intrinsic viscosity of 0.65 and a melting point of 255°C. It is a crystalline polyester. Resin 2: Polyethylene terephthalate with an intrinsic viscosity of 0.75, copolymerized with cyclohexanedimethanol (CHDM) at 32 mol% of the total diol components. An amorphous polyester. Resin 3: Titanium dioxide particle master resin obtained by adding 0.25 parts by mass of a silane coupling agent ("11-100 Additive" manufactured by Toray Dow Corning Co., Ltd.) to 50 parts by mass of titanium dioxide particles (number average particle size 0.25 μm, rutile type), surface treating using a standard method, and then kneading the resulting mixture with 50 parts by mass of Resin 1 in a twin-screw extruder. Glass A: 2mm thick float glass. Glass B: 4mm thick tempered glass. Polycarbonate: 2mm thick polycarbonate (PC) plate. Transparent PVB: 0.76mm thick transparent PVB sheet that does not contain coloring components. Colored PVB (A): Colored PVB sheet with a thickness of 0.76 mm containing coloring components (visible light transmittance: 10%). Colored PVB (B): Colored PVB sheet with a thickness of 0.76 mm (visible light transmittance: 5%) containing coloring components. Colored adhesive: Acrylic colored adhesive containing coloring components (used in a layer thickness of 100 μm, visible light transmittance: 15%).

[0074] (Reference example 1) Two twin-screw extruders were prepared. Resin 1 was supplied to one twin-screw extruder (extruder A), and a mixture of resins 1 and 2 (49:51 by mass) was supplied to the other twin-screw extruder (extruder B). The melted resins were then passed through five FSS-type leaf disc filters, and then introduced into a feedblock with 801 layers while being metered so that the resin discharged from extruder A and extruder B had a discharge ratio of 1.2:1.0. The extrusion temperature and extrusion rotation speed were adjusted so that the resin viscosity immediately before entering the feedblock was 260 Pa·s on the extruder A side and 240 Pa·s on the extruder B side. The difference between the maximum extrusion temperature setting and the resin temperature immediately before entering the feedblock was 8°C on the extruder A side, and 15°C on the extruder B side. In the feed block, to obtain a film with a reflection band of 100 nm or more in the wavelength range of 400 nm to 750 nm, the thickness of each layer was gradually increased from one surface to the other, and 401 layers of resin extruded from Extruder A and 400 layers of resin extruded from Extruder B were alternately laminated in the thickness direction. The resulting laminate structure (801 layers in total) was fed into a multi-manifold die, and layers of resin 1 fed from a separate single-screw extruder were formed on both surfaces to form a sheet. The sheet was then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25°C by electrostatic application, resulting in a cast sheet consisting of 803 layers. The resulting cast sheet was then heated using a group of rolls set at 80°C and stretched 3.0 times in the longitudinal direction at a stretching speed of 180% / sec while rapidly heating both sides using radiation heaters, and then temporarily cooled. Next, this uniaxially stretched film was introduced into a tenter, preheated with hot air at 100°C, and then stretched 3.3 times in the width direction at a temperature of 110°C and a stretching speed of 30% / sec. The stretched film was then heat-treated in the tenter with hot air at 235°C, and subsequently subjected to a 5% relaxation treatment in the width direction at the same temperature, after which it was slowly cooled to room temperature and wound up. The resulting multilayer film had a thickness of 100 μm and was designated Film A. The composition, extrusion conditions, and layer structure are shown in Table 1.

[0075] (Reference examples 2~8) Multilayer films having a thickness of 100 μm were obtained in the same manner as in Example 1, except that the composition, extrusion conditions, and layer structure were as shown in Table 1. The obtained films were named films B to H in this order.

[0076] (Reference example 9) A single-layer film having a thickness of 100 μm was obtained in the same manner as in Example 1, except that a single-screw extruder was used and the composition, extrusion conditions, and layer structure were as shown in Table 1. Next, one side of the obtained single-layer film was laminate-coated with multiple metal thin film layers, each with a thickness of 5 to 20 nm, using a sputtering method, so that the total thickness was 50 nm.

[0077] (Reference example 10) A metal thin film coated film was obtained in the same manner as in Reference Example 9, except that the thickness of the metal thin film layer was as shown in Table 1. This was designated Film J.

[0078] (Reference example 11) A single layer film was obtained in the same manner as in Reference Example 9, except that no metal thin film layer was provided. This was designated Film K.

[0079] [Table 1]

[0080] Example 1 The laminate was made of glass, transparent PVB, film A, colored PVB (A), and glass in that order, and then held at 90°C for 30 minutes in a vacuum laminator and vacuum pressed to obtain a laminate. The evaluation results are shown in Table 2.

[0081] (Examples 2 to 12, Comparative Examples 1 to 3) A laminate was obtained in the same manner as in Example 1, except that the layer structure and the types of film and colored PVB were as shown in Table 1. The evaluation results are shown in Table 2. In Example 10 and Comparative Example 1, the metal thin film layer of the film was positioned on the transparent PVB sheet side.

[0082] [Table 2]

[0083] The film type "A+H" in the table is a 205 μm thick film formed by laminating Film A and Film H with an acrylic adhesive. The visible light reflectance (%) and visible light absorptance (%) of the film of Example 12 are both values ​​for Film 1, which is in the middle position. [Industrial Applicability]

[0084] The present invention makes it possible to provide a laminate that combines high heat insulation and high designability without compromising design, even in applications where high heat insulation is required due to the proximity to the bodies of passengers, such as sunroofs and rear windows of automobiles. The present invention is mainly used as a light control window in transportation facilities and buildings.

Claims

1. A laminate comprising a glass plate or a polycarbonate plate having a thickness of at least 10 mm or less, a reflective photochromic layer, and an absorptive photochromic layer, wherein the solar heat gain coefficient T ｔｓ is 30% or less, and the absolute value R of the difference between the average reflectance (%) of the front and back surfaces in the wavelength range of 400 to 750 nm Ａ has a width of 100 nm or more, and For each of the front and back surfaces, the average reflectance of each band is determined while moving a 100 nm wide band in 1 nm increments in the wavelength range of 400 to 750 nm, and the maximum values ​​of the average reflectance of the front and back surfaces are compared, and the surface with the larger value is designated as surface A. The difference R MAX -R MIN between the maximum value R MAX of the average reflectance and the minimum value R MIN of the average reflectance of surface A is 10% or less, On surface A, the standard deviation of reflectance in the wavelength range of 400 to 750 nm is 10% or less; When the relative average reflectance (%) of surface A in the visible light region is R r and the absolute average reflectance (%) of surface A in the visible light region at an angle of 20° is R a20 , 100×R a20 / R r is 80 or less, A laminate characterized in that the visible light transmittance of the absorptive photochromic layer is less than 50%.

2. 2. The laminate according to claim 1, wherein the visible light transmittance is 10% or less.

3. 3. The laminate according to claim 1, wherein the reflective photochromic layer has a visible light reflectance of 30% or more.

4. 4. The laminate according to claim 1, wherein the average transmittance in the wavelength range of 850 to 1150 nm is 70% or less.

5. 5. The laminate according to claim 1, wherein the reflective photochromic layer has a visible light absorptance of less than 5%.

6. 6. The laminate according to claim 1, wherein the laminate has an electromagnetic wave transmission loss of 1 dB or less at a frequency of 28 GHz.

7. A vehicle sunroof comprising the laminate according to any one of claims 1 to 6.

8. A vehicle rear window comprising the laminate according to any one of claims 1 to 6.

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