JPWO2015104981A1 - Infrared reflective film, method for producing infrared reflective film, and method for producing laminated glass - Google Patents

Abstract

An object of the present invention is to provide an infrared reflective film having high visible light transmittance and excellent heat insulation effect against solar radiation, electromagnetic wave permeability, and excellent curved surface followability, color unevenness resistance, and elongation at break, and an infrared reflective film. It is providing the manufacturing method and the manufacturing method of a laminated glass using the same. The infrared reflective film of the present invention is an infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin, wherein both surfaces of the infrared reflective layer unit each have a polyvinyl acetal resin film. To do.

Description

  The present invention relates to an infrared reflective film, a method for producing an infrared reflective film, and a method for producing a laminated glass using the same, and more specifically, visible light transmittance, heat insulating effect, electromagnetic wave permeability, curved surface followability, color unevenness resistance, In addition, the present invention relates to an infrared reflective film excellent in elongation at break and a method for producing the same, and a method for producing a laminated glass including the infrared reflective film.

  In recent years, heat-insulating glass with high heat insulation or heat insulation has been widely distributed in the market with the aim of blocking the heat generated by sunlight entering from the car windows, reducing the operating rate of the air conditioner in the car, and promoting energy conservation. doing.

  For example, Japanese Patent Application Laid-Open No. 2008-24538 discloses an inner glass / first resin layer / infrared reflective film containing a conductor such as ITO (indium tin oxide) as an infrared absorbing material / second resin layer / A laminated glass in which an outer glass is laminated is disclosed. Japanese Unexamined Patent Application Publication No. 2010-222233 discloses a laminated glass in which a functional plastic film having an infrared reflection layer and an infrared absorption layer is sandwiched between two glass substrates with a thermoplastic resin adhesive. . Japanese Patent Laid-Open No. 2007-148330 discloses that a near-infrared reflective film having a dielectric multilayer film is formed on a polymer resin sheet, and the near-infrared reflective film is sandwiched between two plate glasses through an intermediate film. A near-infrared reflective laminated glass having the above structure is disclosed.

  However, the conventional laminated glass still has various problems.

  For example, in laminated glass using a thermal barrier film composed only of a conductor such as ITO, which is an infrared absorber, heat rays absorbed by the infrared absorbing layer are converted into thermal energy, and the generated thermal energy is transferred to the inside of the vehicle. Due to the diffusion movement, there is a problem that the heat shielding effect is low.

  On the other hand, a metal layer (silver / gold layer) formed by vapor deposition, a layer containing titanium oxide particles, and an ITO layer are laminated on both sides of a transparent substrate of 125 μm or less, and the thermal contraction rate of these constituent layers is specified. A functional film (heat ray reflective film) is disclosed (for example, see Patent Document 1). Further, Patent Document 1 describes a method of producing a laminated glass by sandwiching a polyvinyl acetal resin film as an intermediate film with safety glass for this functional film.

  In addition, laminated glass is produced by laminating a surface layer composed of a polyvinyl acetal resin on both sides of an intermediate substrate composed of a thermoplastic film having a functional layer such as a metal oxide layer formed by vapor deposition. Is disclosed (for example, see Patent Document 2).

  However, the methods disclosed in Patent Document 1 and Patent Document 2 are both formed by forming a metal layer or a metal oxide layer using a sputtering method or a chemical vapor deposition method (CVD method). In this method, an infrared reflection type heat shielding effect is exhibited on the laminated glass. However, these methods certainly exhibit a certain degree of effect in terms of reflecting heat rays, but at the same time, the radio waves are also reflected and electromagnetic waves are reflected. Since it does not have transparency, there is a problem in that the communication of electronic devices such as ETC and mobile phones mounted in the vehicle is troubled.

  In addition, functional layers such as a metal layer and a metal oxide layer are mainly formed by a vapor deposition method, but the formed functional layer itself is a layer having relatively fragile characteristics and has poor curved surface followability. As a result, when mounted on a curved surface such as a windshield of a car, the functional layer is prone to film breakage such as cracks and is inferior in breaking elongation. In addition, since a functional layer is formed by a vapor deposition method, a large-scale vacuum facility or the like is required, which places a burden on production cost and production efficiency.

  On the other hand, an infrared reflective layer is formed by a wet coating method using an aqueous binder, for example, polyvinyl alcohol, and a laminated glass provided with this is known, but polyvinyl alcohol having high water absorption is used for the binder. Therefore, when a laminated glass is produced using this, the film thickness of each polyvinyl alcohol layer will fluctuate due to the difference in moisture content unless the moisture content in the plurality of infrared reflective layers is adjusted within a certain range. As a result, there has been a problem that color unevenness variation is likely to occur.

  Therefore, it is desired to develop an infrared reflective film that has both a sufficient heat shielding effect and electromagnetic wave permeability, and has high transparency, curved surface followability (fragility resistance), color unevenness resistance, and high elongation at break. .

JP-A-60-225747 JP 2004-168646 A

  The present invention has been made in view of the above problems, and its purpose is to have high visible light transmittance and excellent heat insulation effect against solar radiation, electromagnetic wave permeability, curved surface followability, color unevenness resistance, and breakage. An object of the present invention is to provide an infrared reflective film excellent in elongation, a method for producing the same, and a method for producing a laminated glass including the infrared reflective film.

  As a result of intensive studies in view of the above problems, the present inventor has an infrared reflection layer unit containing at least a water-soluble binder resin and metal oxide particles, and each of the infrared reflection layer units has a polyvinyl acetal type on both sides. Infrared reflective film characterized by having a resin film, high visible light transmittance, excellent heat insulation effect against solar radiation, electromagnetic wave permeability, curved surface followability, color unevenness resistance, and elongation at break The present inventors have found that an infrared reflective film excellent in thickness can be obtained, and have reached the present invention.

  That is, the said subject of this invention is solved by the following means.

1. An infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles,
An infrared reflective film comprising a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit, respectively.

  2. The infrared reflective film according to item 1, wherein the polyvinyl acetal resin film is a polyvinyl butyral film.

  3. Item 1 or 2, wherein the infrared reflective layer in contact with the polyvinyl acetal resin film constituting the infrared reflective layer unit contains silicon dioxide in the range of 10 to 60% by mass as the metal oxide particles. The infrared reflective film according to Item 2.

  4). The infrared reflective layer unit has a high refractive index infrared reflective layer containing a first water-soluble binder resin and first metal oxide particles on at least one surface side on a transparent substrate, and a second water-soluble layer. 1 to 3 characterized by having an infrared reflective layer group in which an adhesive binder resin and a low refractive index infrared reflective layer containing second metal oxide particles are alternately laminated. The infrared reflective film as described in any one of.

  5. The infrared reflective film according to claim 4, wherein the infrared reflective layer unit has the alternately laminated infrared reflective layer group on both surfaces of a transparent substrate.

6). A method for producing an infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles,
A method for producing an infrared reflective film, comprising producing a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit.

  7). The method for producing an infrared reflective film according to item 6, wherein the polyvinyl acetal resin film is a polyvinyl butyral film.

  8). The infrared reflective film according to Item 6 or 7, wherein a polyvinyl acetal resin film is bonded to both surfaces of the infrared reflective layer unit at a pressure within a range of 1 to 50 MPa. Production method.

  9. The infrared reflecting layer in contact with the polyvinyl acetal resin film constituting the infrared reflecting layer unit is formed by containing silicon dioxide in the range of 10 to 60% by mass as the metal oxide particles. The method for producing an infrared reflective film according to any one of Items 6 to 8.

  10. The infrared reflective layer unit has a high refractive index infrared reflective layer containing a first water-soluble binder resin and first metal oxide particles on at least one surface side on a transparent substrate, and a second water-soluble layer. Item 9 to Item 9, wherein an infrared reflective layer group is produced by alternately laminating a low refractive index infrared reflective layer containing a conductive binder resin and second metal oxide particles. The manufacturing method of the infrared reflective film as described in any one of the above.

  11. The method for producing an infrared reflective film according to item 10, wherein the infrared reflective layer unit is produced by forming the alternately laminated infrared reflective layer group on both surfaces of the transparent substrate.

  12 A method for producing a laminated glass, wherein the infrared reflective film according to any one of items 1 to 5 is sandwiched and produced between two glass substrates.

  By the above means of the present invention, an infrared reflective film and an infrared reflective film having high visible light transmittance and excellent heat insulation effect against solar radiation, electromagnetic wave transmittance, and excellent curved surface followability, color unevenness resistance, and elongation at break The manufacturing method of this and the manufacturing method of a laminated glass using the same can be provided.

  The expression mechanism / action mechanism that has achieved the above-described objective effect of the present invention is not fully clarified, but is presumed as follows.

  In the conventional method of forming a transparent conductor, the method of forming an infrared reflective layer by vapor deposition using a metal oxide can reduce the film thickness, but it is formed of inorganic metal oxide particles alone. The deposited layer becomes a hard and brittle layer, its resistance to curved bending such as bending is weak, and a hard and brittle film is easily broken when subjected to stress, and has a low degree of stretching relative to the degree of stretching of the transparent substrate. Become. In the present invention, in order to impart flexibility to the infrared reflecting layer in consideration of the above problems, the curved flexibility and elongation can be deteriorated compared with the case of a transparent substrate alone by adding a water-soluble binder to the metal oxide layer. Less is. In addition, the water-soluble binder has a characteristic of being weak against moisture, but the water-resistant binder has a water-resistant property by sandwiching the infrared reflective layer containing the water-soluble binder having water absorption between the polyvinyl acetal resin films. Was able to clear the problem.

Schematic sectional view showing an example of the configuration of the infrared reflective film of the present invention Schematic sectional view showing another example of the configuration of the infrared reflective film of the present invention

The infrared reflective film of the present invention is an infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles,
Each of the infrared reflective layer units has a polyvinyl acetal resin film on each side. This feature is a technical feature common to the inventions according to claims 1 to 12.

  As an embodiment of the present invention, the polyvinyl acetal resin film is a polyvinyl butyral film from the viewpoint of more manifesting the intended effect of the present invention. It is preferable from the viewpoint that an appropriate breaking elongation can be imparted to the infrared reflective film.

  Further, the outermost infrared reflective layer in contact with the polyvinyl acetal resin film constituting the infrared reflective layer unit contains silicon dioxide as metal oxide particles in a range of 10 to 60% by mass, In addition to preventing clouding of the infrared reflective layer due to moisture entering from the outside, when the polyvinyl acetal resin film is bonded thereon, the silicon dioxide particles contained in the outermost infrared reflective layer are polyvinyl acetal based It is preferable from the viewpoint that the adhesiveness between the infrared reflective layer unit and the polyvinyl acetal resin film can be improved by biting into the resin film and expressing the anchor effect.

  In addition, the infrared reflective layer unit has a high refractive index infrared reflective layer containing a first water-soluble binder resin and first metal oxide particles on at least one surface side on the transparent substrate, and a second It is the structure which has the infrared reflective layer group which laminated | stacked alternately the low-refractive-index infrared reflective layer containing water-soluble binder resin and 2nd metal oxide particle, Furthermore, an infrared reflective layer unit is alternately It is preferable to have the laminated infrared reflective layer group on both surfaces of the transparent substrate from the viewpoint of exhibiting a more excellent heat insulating effect and electromagnetic wave permeability.

  Moreover, in the manufacturing method of the infrared reflective film of this invention, it is a manufacturing method of the infrared reflective film which has an infrared reflective layer unit containing at least water-soluble binder resin, Comprising: On both surfaces of the said infrared reflective layer unit, respectively, It is characterized by being manufactured by bonding an acetal resin film.

  Furthermore, the adhesiveness between the infrared reflective layer unit and the polyvinyl acetal resin film can be produced by bonding a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit at a pressure within the range of 1 to 50 MPa. It is preferable from the viewpoint that can be improved.

  Hereinafter, the component of the infrared reflective film of this invention and the form and aspect for implementing this invention are demonstrated in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

《Basic structure of infrared reflective film》
The infrared reflective film of the present invention has an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles, and has a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit. It is characterized by.

  The infrared reflective layer unit constituting the infrared reflective film of the present invention refers to a structural unit having an infrared reflective layer containing at least one water-soluble binder resin and metal oxide particles on a transparent substrate, preferably, A high refractive index infrared reflective layer (hereinafter also simply referred to as a high refractive index layer) containing a first water-soluble binder resin and first metal oxide particles on a transparent substrate, and a second water-soluble layer A preferred embodiment is a configuration having an infrared reflective layer group in which low-refractive-index infrared reflective layers (hereinafter also simply referred to as low-refractive index layers) containing a binder resin and second metal oxide particles are alternately laminated. It is.

  Moreover, in the infrared reflective layer unit according to the present invention, it is one of preferred embodiments that the infrared reflective layer group is formed on both surfaces of the transparent substrate.

  Hereafter, the typical structure of the infrared reflective film of this invention is demonstrated using figures. However, the structure of the infrared reflective film described here is an example, and is not limited thereto. In the following description of the figures, the numbers in parentheses described after each constituent element indicate the reference numerals in the figures.

  FIG. 1 is a schematic cross-sectional view showing a configuration including an infrared reflective layer unit having an infrared reflective layer group on one surface side of a transparent substrate in the configuration of the infrared reflective film of the present invention.

In FIG. 1, the infrared reflective film (1) of the present invention is constituted by bonding an infrared reflective layer unit (U) and polyvinyl acetal resin films (3A and 3B) on both surfaces thereof. Furthermore, the infrared reflective layer unit (U), as an example, on the transparent substrate (2), a high refractive index infrared reflective layer containing the first water-soluble binder resin and the first metal oxide particles, It has the infrared reflective layer group (ML) which laminated | stacked alternately the 2nd water-soluble binder resin and the low-refractive-index infrared reflective layer containing a 2nd metal oxide particle. The infrared reflective layer group (ML) is composed of n layers of infrared reflective layers (T _{1 to} T _n ), and refracts T ₁ , T ₃ , T ₅ , (omitted), T _n−2 , and T _n, for example. It is composed of a low refractive index layer having a refractive index in the range of 1.10 to 1.60, and T ₂ , T ₄ , T ₆ , (omitted), and T _n-1 have a refractive index of 1.80 to 2.50. An example of the configuration is a high refractive index layer in the range of. The refractive index as used in the field of this invention is the value measured in the environment of 25 degreeC.

In the present invention, the infrared reflective layer in contact with the polyvinyl acetal resin film (3A) constituting the infrared reflective layer unit _(U) (T n) is, as the metal oxide particles of silicon dioxide of 10 to 60 wt% Containing within the range prevents whitening of the infrared reflecting layer due to moisture entering from the outside, and the infrared reflecting layer (T _n ) is contained when the polyvinyl acetal resin film (3A) is bonded. It is preferable from the viewpoint of improving the adhesion between the infrared reflective layer unit (U) and the polyvinyl acetal resin film (3A) by the silicon dioxide particles that bite into the polyvinyl acetal resin film and exhibit an anchor effect.

  FIG. 2 is a schematic sectional view showing another example of the configuration of the infrared reflective film of the present invention, in which an infrared reflective layer unit having an infrared reflective layer group is provided on both surfaces of a transparent substrate.

  In contrast to the configuration shown in FIG. 1, the configuration shown in FIG. 2 is that the transparent substrate (2) is provided with an infrared reflective layer group (MLa) on one side (upper side of the paper) and on the other side (under the page). Infrared reflective layer group (MLb) is provided on the side) to form an infrared reflective layer unit (U), and polyvinyl acetal resin films (3A and 3B) are bonded to the outermost surfaces of the infrared reflective film. (1) is formed.

In the configuration shown in FIG. 2 as well, the low refractive index layer and the high refractive index layer are alternately laminated to form the infrared reflective layer group (MLa and MLb), and in addition, on the polyvinyl acetal resin film (3A and 3B) It is preferable that the infrared reflective layer (Ta _n and Tb _n ) in contact contains silicon dioxide as metal oxide particles in a range of 10 to 60% by mass.

  As shown in FIGS. 1 and 2, the infrared reflective film of the present invention has an infrared reflective layer unit containing at least a water-soluble binder resin, and both surfaces of the infrared reflective layer unit are respectively polyvinyl acetal resin films. Furthermore, the infrared reflective layer unit has a structure having an infrared reflective layer containing at least one water-soluble binder resin on the transparent substrate, and preferably, on the transparent substrate, A high refractive index layer containing 1 water-soluble binder resin and first metal oxide particles, and a low refractive index layer containing second water-soluble binder resin and second metal oxide particles are alternately laminated. The infrared reflective layer group is configured.

  As an infrared reflective film of this invention, you may provide an infrared rays absorption layer, a heat insulation layer, a hard-coat layer, an adhesion layer etc. other than said each structural layer as needed.

  The total thickness of the infrared reflective film of the present invention is not particularly limited, but is in the range of 250 to 1500 μm, preferably in the range of 400 to 1200 μm, more preferably in the range of 600 to 1000 μm, Especially preferably, it exists in the range of 750-900 micrometers.

  As an optical characteristic of the infrared reflective film of the present invention, the visible light transmittance measured by JIS R 3106: 1998 is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more. It is. Moreover, it is preferable to have the area | region where a reflectance exceeds 50% in the area | region of wavelength 900-1400 nm.

<Each component of infrared reflective film>
[Transparent substrate]
The transparent substrate applicable to the present invention is not particularly limited as long as it is transparent, and examples thereof include glass, quartz, and a transparent resin film. From the viewpoint of imparting flexibility and suitability for production (manufacturing process suitability). Is preferably a transparent resin film.

  The thickness of the transparent substrate according to the present invention is preferably in the range of 30 to 200 μm, more preferably in the range of 30 to 100 μm, and still more preferably in the range of 35 to 70 μm. If the thickness of the transparent resin film is 30 μm or more, wrinkles or the like are less likely to occur during handling, and if the thickness is 200 μm or less, when the laminated glass is produced, to the curved glass surface when the glass substrate is laminated. The follow-up performance is improved and wrinkles are less likely to occur.

  The transparent substrate according to the present invention is preferably a biaxially oriented polyester film, but a polyester film that has not been stretched or at least one of which has been stretched can also be used. From the viewpoint of strength improvement and thermal expansion suppression, a stretched film is preferable. In particular, when the laminated glass provided with the infrared reflective film of the present invention is used as a windshield of an automobile, the transparent substrate is more preferably a stretched film.

  The transparent substrate according to the present invention has a thermal shrinkage within a range of 0.1 to 3.0% at a temperature of 150 ° C. from the viewpoint of preventing generation of wrinkles of the infrared reflective film and cracking of the infrared reflective layer. It is preferable that it is in the range of 1.5 to 3.0%, more preferably in the range of 1.9 to 2.7%.

  The transparent substrate applicable to the infrared reflective film of the present invention is not particularly limited as long as it is transparent, but various resin films are preferably used. For example, polyolefin films (for example, polyethylene, polypropylene, etc.) Polyester film (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, triacetyl cellulose film and the like can be used, and polyester film and triacetyl cellulose film are preferable.

  Although it does not specifically limit as a polyester film (henceforth only polyester), It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components. Examples of the dicarboxylic acid component that is one of the main components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, and diphenyl ether dicarboxylic acid. , Diphenylethane dicarboxylic acid, cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, phenylindane dicarboxylic acid, and the like. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, Examples thereof include bis (4-hydroxyphenyl) sulfone, bisphenol full orange hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, and cyclohexanediol. Among the polyesters having these as main constituent components, from the viewpoint of transparency, mechanical strength, dimensional stability, etc., dicarboxylic acid components such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components such as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

  From the viewpoint of facilitating handling, the transparent resin film that is the transparent substrate according to the present invention may contain various particles within a range that does not impair the transparency. Examples of the particles applicable in the present invention include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, and cross-linking. Organic particles such as polymer particles and calcium oxalate can be mentioned. Examples of the method of adding these particles include a method of adding particles in the polyester as a raw material, a method of adding them directly by an extruder, and the like. You may employ | adopt and may use two methods together. In the present invention, additives may be added in addition to the above particles as necessary. Examples of such additives include stabilizers, lubricants, cross-linking agents, anti-blocking agents, antioxidants, dyes, pigments, and ultraviolet absorbers.

  The transparent resin film which is a transparent substrate can be produced by a conventionally known general method. For example, an unstretched transparent resin film that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it into a film shape with an annular die or a T-die and quenching it. it can. The unstretched transparent resin film is uniaxially stretched, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular simultaneous biaxial stretching, and other known methods such as transparent resin film flow (vertical axis) direction. Alternatively, a stretched transparent resin film can be produced by stretching in the direction perpendicular to the flow direction of the transparent resin film (horizontal axis). Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of the transparent resin film, it is preferably 2 to 10 times in the vertical axis direction and the horizontal axis direction.

  In addition, the transparent resin film may be subjected to relaxation treatment or off-line heat treatment in terms of dimensional stability. It is preferable that the relaxation treatment is performed in a process from the heat setting in the stretching process of the polyester film to the winding in the transversely stretched tenter or after exiting the tenter. The relaxation treatment is preferably performed at a treatment temperature in the range of 80 to 200 ° C, and more preferably at a treatment temperature in the range of 100 to 180 ° C. Moreover, it is preferable that the relaxation rate is within a range of 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is within a range of 2 to 6%. The relaxation-treated transparent resin film is improved in heat resistance by performing off-line heat treatment, and further has good dimensional stability.

In the transparent resin film, it is preferable to form an undercoat layer by applying an undercoat layer coating solution inline on one side or both sides in the film forming process. Examples of resins used in the undercoat layer coating solution useful in the present invention include polyester resins, acrylic-modified polyester resins, polyurethane resins, acrylic resins, vinyl resins, vinylidene chloride resins, polyethyleneimine vinylidene resins, polyethyleneimine resins, and polyvinyl resins. Alcohol resin, modified polyvinyl alcohol resin, gelatin and the like can be mentioned, and any of them can be preferably used. A conventionally well-known additive can also be added to these undercoat layers. The undercoat layer can be formed by applying a known method such as a roller coating method, a gravure coating method, a knife coating method, a dip coating method, or a spray coating method. The coating amount of the undercoat layer is preferably about 0.01 to 2.0 g / m ² (dry state).

[Infrared reflective layer group]
The infrared reflective layer group according to the present invention (ML shown in FIG. 1, MLa, MLb shown in FIG. 2) may have at least one infrared reflective layer, which is the object effect of the present invention. From the viewpoint of exhibiting excellent heat insulation effect, heat shielding effect and electromagnetic wave permeability against solar radiation, it is preferably formed in a form in which a plurality of infrared reflection layer groups are laminated, more preferably the first water-soluble binder. Infrared having a structure in which a high refractive index layer containing a resin and first metal oxide particles, and a low refractive index layer containing a second water-soluble binder resin and second metal oxide particles are alternately laminated. It is a reflective layer group.

  In the infrared reflective layer group according to the present invention, the layer thickness per layer of the high refractive index layer is preferably in the range of 20 to 800 nm, and more preferably in the range of 50 to 350 nm. Similarly, the layer thickness per layer of the low refractive index layer is preferably in the range of 20 to 800 nm, and more preferably in the range of 50 to 350 nm.

  Here, when measuring the layer thickness of each layer per layer, the high refractive index layer and the low refractive index layer may have a clear interface between them or may change gradually. When the interface is gradually changing, the maximum refractive index-minimum refractive index = Δn in the region where the layers are mixed and the refractive index continuously changes, the minimum refractive index between two layers + Δn The point of / 2 is regarded as the layer interface.

  In the present invention, the metal oxide concentration profile of the infrared reflective layer group formed by alternately laminating the high refractive index layer and the low refractive index layer is etched from the surface to the depth direction using a sputtering method, Using an XPS surface analyzer, the atomic composition ratio can be measured by sputtering at a rate of 0.5 nm / min with the outermost surface being 0 nm. It is also possible to obtain the cut surface by cutting the infrared reflective layer group and measuring the atomic composition ratio with an XPS surface analyzer. In the mixed region, when the concentration of the metal oxide changes discontinuously, the boundary can be confirmed by a tomographic photograph taken with an electron microscope (TEM).

  The XPS surface analyzer is not particularly limited and any model can be used. For example, ESCALAB-200R manufactured by VG Scientific, Inc. can be used. Mg is used for the X-ray anode, and measurement is performed at an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA).

  From the viewpoint of productivity, the infrared reflective layer group according to the present invention is preferably in the range of 6 to 100 layers, more preferably in the range of 6 to 100 layers, as the range of the total number of high refractive index layers and low refractive index layers. It is within the range of 40 layers, more preferably within the range of 9 to 30 layers.

  In the infrared reflective layer group according to the present invention, it is preferable to design a large difference in refractive index between the high refractive index layer and the low refractive index layer from the viewpoint that the infrared reflectance can be increased with a small number of layers. . In the present invention, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is preferably 0.10 or more, more preferably 0.30 or more, and further preferably 0.35 or more. Especially preferably, it is 0.40 or more. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used.

  Further, the reflectance in the specific wavelength region is determined by the refractive index difference between two adjacent layers and the number of stacked layers, and the same reflectance can be obtained with a smaller number of layers as the difference in refractive index increases. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain a near-infrared reflectance of 90% or more, if the difference in refractive index is less than 0.1, it is necessary to laminate 200 layers or more, which not only decreases productivity but also scattering at the interface of the layers. Becomes larger, the transparency is lowered, and it becomes very difficult to manufacture without failure. From the standpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but practically about 1.4 is the limit.

  In the infrared reflective layer according to the present invention, a layer configuration in which the lowermost layer adjacent to the transparent resin film is a low refractive index layer is preferable from the viewpoint of adhesion to the transparent resin film. The layer adjacent to the polyvinyl acetal resin film is also preferably a low refractive index layer containing silicon dioxide in the range of 10 to 60% by mass as metal oxide particles.

  In the present invention, the first water-soluble binder resin contained in the high refractive index layer and the second water-soluble binder resin contained in the low refractive index layer are each preferably polyvinyl alcohol. Moreover, it is preferable that the saponification degree of the polyvinyl alcohol contained in the high refractive index layer is different from the saponification degree of the polyvinyl alcohol contained in the low refractive index layer. Furthermore, the first metal oxide particles contained in the high refractive index layer are preferably titanium oxide particles, and more preferably titanium oxide particles surface-treated with a silicon-containing hydrated oxide. .

(High refractive index layer)
The high refractive index layer according to the present invention contains a first water-soluble binder resin and first metal oxide particles, and if necessary, a curing agent, other binder resin, a surfactant, and various additives. Etc. may be included.

  The refractive index of the high refractive index layer according to the present invention is preferably 1.80 to 2.50, more preferably 1.90 to 2.20.

(First water-soluble binder resin)
When the first water-soluble binder resin according to the present invention is dissolved in water at a concentration of 0.5% by mass at the temperature at which the water-soluble binder resin is most dissolved, the G2 glass filter (maximum pores 40 to 50 μm) is used. The mass of the insoluble matter that is filtered off when filtered in ()) is within 50 mass% of the added water-soluble binder resin.

  It is preferable that the weight average molecular weight of the 1st water-soluble binder resin which concerns on this invention exists in the range of 1000-200000. Furthermore, the inside of the range of 3000-40000 is more preferable.

  The weight average molecular weight referred to in the present invention can be measured by a known method, for example, static light scattering, gel permeation chromatography (GPC), time-of-flight mass spectrometry (TOF-MASS), or the like. In the present invention, it is measured by a gel permeation chromatography method which is a generally known method.

  The content of the first water-soluble binder resin in the high refractive index layer is preferably in the range of 5 to 50% by mass with respect to 100% by mass of the solid content of the high refractive index layer, and is 10 to 40% by mass. It is more preferable to be within the range.

  The first water-soluble binder resin applied to the high refractive index layer is preferably polyvinyl alcohol. Moreover, it is preferable that the 2nd water-soluble binder resin applied to the low refractive index layer mentioned later is also polyvinyl alcohol. Therefore, in the following, polyvinyl alcohol contained in the high refractive index layer and the low refractive index layer will be described together.

<Polyvinyl alcohol>
In the present invention, it is preferable to apply two or more types of polyvinyl alcohol having different saponification degrees to the high refractive index layer and the low refractive index layer. In the following description, in order to distinguish each, polyvinyl alcohol as a water-soluble binder resin used in the high refractive index layer is polyvinyl alcohol (A), and polyvinyl alcohol as the water-soluble binder resin used in the low refractive index layer is It is called polyvinyl alcohol (B). In addition, when each refractive index layer contains a plurality of polyvinyl alcohols having different saponification degrees and polymerization degrees, the polyvinyl alcohol having the highest content in each refractive index layer is changed to polyvinyl alcohol (A ) And polyvinyl alcohol (B) in the low refractive index layer.

  The “degree of saponification” as used in the present invention is the ratio of hydroxy groups to the total number of acetyloxy groups (derived from the starting vinyl acetate) and hydroxy groups in polyvinyl alcohol.

  In addition, when referring to “polyvinyl alcohol having the highest content in the refractive index layer” herein, the degree of polymerization is calculated assuming that the polyvinyl alcohol having a saponification degree difference of 3 mol% or less is the same polyvinyl alcohol. . However, a low polymerization degree polyvinyl alcohol having a polymerization degree of 1000 or less is a different polyvinyl alcohol (even if there is a polyvinyl alcohol having a saponification degree difference of 3 mol% or less, it is not regarded as the same polyvinyl alcohol). Specifically, when polyvinyl alcohol having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% is contained in the same layer by 10 mass%, 40 mass%, and 50 mass%, respectively. These three polyvinyl alcohols are the same polyvinyl alcohol, and the mixture of these three is polyvinyl alcohol (A) or (B). Further, the above-mentioned “polyvinyl alcohol having a saponification degree difference of 3 mol% or less” is sufficient if it is within 3 mol% when attention is paid to any polyvinyl alcohol. For example, the saponification degrees are 90 mol% and 91 mol, respectively. %, 92 mol%, and 94 mol% of polyvinyl alcohol, when paying attention to 91 mol% of polyvinyl alcohol, the difference in the degree of saponification of any polyvinyl alcohol is within 3 mol%, so that the same polyvinyl alcohol is obtained.

  When polyvinyl alcohol having a saponification degree different by 3 mol% or more is contained in the same layer, it is regarded as a mixture of different polyvinyl alcohols, and the polymerization degree and the saponification degree are calculated for each. For example, PVA203: 5% by mass, PVA117: 25% by mass, PVA217: 10% by mass, PVA220: 10% by mass, PVA224: 10% by mass, PVA235: 20% by mass, PVA245: 20% by mass, most contained A large amount of PVA (polyvinyl alcohol) is a mixture of PVA 217 to 245 (the difference in the degree of saponification of PVA 217 to 245 is within 3 mol%, and thus is the same polyvinyl alcohol), and this mixture is polyvinyl alcohol (A) or ( B). Thus, in the mixture of PVA 217 to 245 (polyvinyl alcohol (A) or (B)), the polymerization degree is (1700 × 0.1 + 2000 × 0.1 + 2400 × 0.1 + 3500 × 0.2 + 4500 × 0.7) / 0.7 = 3200, and the degree of saponification is 88 mol%.

  The difference in the absolute value of the degree of saponification between the polyvinyl alcohol (A) and the polyvinyl alcohol (B) is preferably 3 mol% or more, and more preferably 5 mol% or more. If it is such a range, since the interlayer mixing state of a high refractive index layer and a low refractive index layer will become a preferable level, it is preferable. Moreover, although the difference of the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is so preferable that it is separated, it is 20 mol% or less from the viewpoint of the solubility to water of polyvinyl alcohol. It is preferable.

  Moreover, it is preferable that the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is 75 mol% or more from a soluble viewpoint to water. Furthermore, intermixing of the high refractive index layer and the low refractive index layer means that one of the polyvinyl alcohol (A) and the polyvinyl alcohol (B) has a saponification degree of 90 mol% or more and the other is 90 mol% or less. It is preferable to bring the state to a desirable level. It is more preferable that one of the polyvinyl alcohol (A) and the polyvinyl alcohol (B) has a saponification degree of 95 mol% or more and the other is 90 mol% or less. In addition, although the upper limit of the saponification degree of polyvinyl alcohol is not specifically limited, Usually, it is less than 100 mol% and is about 99.9 mol% or less.

  In addition, the polymerization degree of two kinds of polyvinyl alcohols having different saponification degrees is preferably 1000 or more, particularly preferably those having a polymerization degree in the range of 1500 to 5000, and in the range of 2000 to 5000. Those are more preferably used. When the polymerization degree of polyvinyl alcohol is 1000 or more, there is no crack of the coating film, and when it is 5000 or less, it is preferable from the viewpoint of stabilizing the coating solution. The term “coating liquid is stable” as used in the present invention means that the physical properties of the coating liquid (for example, the viscosity of the coating liquid) are stabilized over time. When the degree of polymerization of at least one of polyvinyl alcohol (A) and polyvinyl alcohol (B) is in the range of 2000 to 5000, it is preferable because cracks in the coating film are reduced and the reflectance at a specific wavelength is improved. Since both the polyvinyl alcohol (A) and the polyvinyl alcohol (B) are 2000 to 5000, the above effect can be more remarkably exhibited.

  “Polymerization degree P” as used in the present invention refers to the viscosity average degree of polymerization, measured in accordance with JIS K6726 (1994), and the limit measured in water at 30 ° C. after completely re-saponifying and purifying PVA. From the viscosity [η] (dl / g), it is obtained by the following formula (1).

Formula (1)
P = ([η] × 10 ³ /8.29) ^{(1 / 0.62)}
The polyvinyl alcohol (B) contained in the low refractive index layer preferably has a saponification degree in the range of 75 to 90 mol% and a polymerization degree in the range of 2000 to 5000. When polyvinyl alcohol having such characteristics is contained in the low refractive index layer, it is preferable in that interfacial mixing is further suppressed. This is considered to be because there are few cracks of a coating film and the setability at the time of application | coating improves.

  As the polyvinyl alcohol (A) and (B) used in the present invention, a synthetic product or a commercially available product may be used. As an example of the commercial item used as polyvinyl alcohol (A) and (B), for example, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, PVA -203, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235 (manufactured by Kuraray Co., Ltd.), JC-25, JC-33, JF-03, JF-04 , JF-05, JP-03, JP-04JP-05, JP-45 (above, manufactured by Nihon Vinegar & Poval Co., Ltd.) and the like.

  As long as the first water-soluble binder resin according to the present invention does not impair the effects of the present invention, in addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate, modified polyvinyl alcohol partially modified May be included. When such a modified polyvinyl alcohol is included, the adhesion, water resistance, and flexibility of the film may be improved. Examples of such modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonionic-modified polyvinyl alcohol, and vinyl alcohol polymers.

  Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups as described in JP-A-61-110483, and the main chain or side chain of the polyvinyl alcohol. Polyvinyl alcohol contained therein and obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

  Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is in the range of 0.1 to 10 mol%, preferably in the range of 0.2 to 5 mol% with respect to vinyl acetate.

  Anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681 and JP-A-63-307979. Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.

  Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. Block copolymer of vinyl compound having hydrophobic group and vinyl alcohol, silanol-modified polyvinyl alcohol having silanol group, reactive group modification having reactive group such as acetoacetyl group, carbonyl group and carboxy group Polyvinyl alcohol etc. are mentioned.

  Examples of vinyl alcohol polymers include Exeval (registered trademark, manufactured by Kuraray Co., Ltd.) and Nichigo G polymer (registered trademark, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

  Two or more types of modified polyvinyl alcohol can be used in combination, such as the degree of polymerization and the type of modification.

  Although content of modified polyvinyl alcohol is not specifically limited, Preferably it exists in the range of 1-30 mass% with respect to the total mass (solid content) of each refractive index layer. If it is in such a range, the said effect will be exhibited more.

  In the present invention, it is preferable to use two types of polyvinyl alcohol having different saponification levels between layers having different refractive indexes.

  For example, when polyvinyl alcohol (A) having a low saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a high saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained within a range of 40 to 100% by mass, more preferably within a range of 60 to 95% by mass, based on the total mass of all polyvinyl alcohols in the layer. The polyvinyl alcohol (B) is preferably contained within a range of 40 to 100% by mass, and more preferably within a range of 60 to 95% by mass with respect to the total mass of all polyvinyl alcohols in the low refractive index layer. When polyvinyl alcohol (A) having a high saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a low saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained within a range of 40 to 100% by mass, more preferably within a range of 60 to 95% by mass, based on the total mass of all polyvinyl alcohols in the layer. The polyvinyl alcohol (B) is preferably contained within a range of 40 to 100% by mass, and more preferably within a range of 60 to 95% by mass with respect to the total mass of all polyvinyl alcohols in the low refractive index layer. When each content is 40% by mass or more, interlayer mixing is suppressed, and the effect that the disturbance of the interface is reduced appears significantly. On the other hand, if content is 100 mass% or less, stability of a coating liquid will improve.

(Other binder resins)
In the present invention, in the high refractive index layer, the first water-soluble binder resin other than polyvinyl alcohol is not limited as long as the high refractive index layer containing the first metal oxide particles can form a coating film. But it can be used without restriction. Moreover, also in the low refractive index layer described later, as the second water-soluble binder resin other than the polyvinyl alcohol (B), the low refractive index layer containing the second metal oxide particles is coated as described above. Any device can be used without limitation as long as it can be formed. However, in consideration of environmental problems and flexibility of the coating film, water-soluble polymers, particularly gelatin, celluloses, thickening polysaccharides, polymers having reactive functional groups, and the like can be preferably used. These water-soluble polymers may be used alone or in combination of two or more.

  In the high refractive index layer, the content of other binder resin used together with polyvinyl alcohol preferably used as the water-soluble binder resin is in the range of 5 to 50% by mass with respect to 100% by mass of the solid content of the high refractive index layer. It can also be used within.

  In the present invention, it is preferable from the viewpoint of environmental protection that an organic solvent need not be used. Therefore, the binder resin is preferably formed of a water-soluble polymer. That is, in the present invention, a water-soluble polymer other than polyvinyl alcohol and modified polyvinyl alcohol can be used as the binder resin in addition to the polyvinyl alcohol and modified polyvinyl alcohol as long as the effect is not impaired.

  The water-soluble polymer is the temperature at which the water-soluble polymer is most dissolved, and when it is dissolved in water at a concentration of 0.5% by mass and filtered through a G2 glass filter (maximum pores 40-50 μm). The mass of the insoluble matter filtered out as a residue is within 50% by mass of the added water-soluble polymer. Among such water-soluble polymers, gelatin, celluloses, thickening polysaccharides, or polymers having reactive functional groups are particularly preferable.

  Hereinafter, the details of these various water-soluble polymers will be described.

<gelatin>
As the gelatin applicable to the present invention, various gelatins that have been widely used in the field of silver halide photographic light-sensitive materials can be applied. For example, in addition to acid-processed gelatin and alkali-processed gelatin, production of gelatin is possible. Enzyme-treated gelatin and gelatin derivatives that undergo enzyme treatment in the process, that is, modified by treatment with a reagent that has an amino group, imino group, hydroxy group, carboxy group as a functional group in the molecule and a group that can react with it. You may have done. Well-known methods for producing gelatin are well known. H. James: The Theory of Photographic Process 4th. ed. Reference can be made to descriptions such as 1977 (Macmillan) 55, Science Photo Handbook (above) 72-75 (Maruzen), Fundamentals of Photographic Engineering-Silver Salt Photo Hen 119-124 (Corona). Also, Research Disclosure Magazine Vol. 176, No. And gelatin described in Section IX of 17643 (December, 1978).

  When gelatin is used, a gelatin hardener can be added as necessary.

  As the hardener that can be used, known compounds that are used as hardeners for ordinary photographic gelatin can be used, for example, vinyl sulfone compounds, urea-formalin condensates, melanin-formalin condensates, epoxy-based hardeners. Examples thereof include organic hardeners such as compounds, aziridine compounds, active olefins and isocyanate compounds, and inorganic polyvalent metal salts such as chromium, aluminum and zirconium.

<Cellulose>
As the celluloses that can be used in the present invention, water-soluble cellulose derivatives can be preferably used. For example, water-soluble cellulose derivatives such as carboxymethyl cellulose (cellulose carboxymethyl ether), methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. Examples thereof include cellulose derivatives, carboxymethyl cellulose (cellulose carboxymethyl ether) and carboxyethyl cellulose which are carboxylic acid group-containing celluloses. Other examples include cellulose derivatives such as nitrocellulose, cellulose acetate propionate, cellulose acetate, and cellulose sulfate.

<Thickening polysaccharide>
The thickening polysaccharide that can be used in the present invention is not particularly limited, and examples thereof include generally known natural simple polysaccharides, natural complex polysaccharides, synthetic simple polysaccharides, and synthetic complex polysaccharides. The details of these polysaccharides can be referred to “Biochemical Encyclopedia (2nd edition), Tokyo Chemical Doujinshi”, “Food Industry” Vol. 31 (1988), p.

  The thickening polysaccharide referred to in the present invention is a saccharide polymer having a large number of hydrogen bonding groups in the molecule. Due to the difference in hydrogen bonding strength between molecules depending on the temperature, the viscosity at low temperature and the viscosity at high temperature are It is a polysaccharide with a large difference from viscosity, and when adding metal oxide fine particles, it causes a viscosity increase that seems to be due to hydrogen bonding with the metal oxide fine particles at low temperatures. The width is a polysaccharide which, when added, causes a viscosity at 15 ° C. to increase by 1.0 mPa · s or more, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more. It is a polysaccharide with ability.

  Examples of the thickening polysaccharide applicable to the present invention include galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum, guaran, etc.), xyloglucan (eg, tamarind gum, etc.), Glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabinogalactoglycan (eg, soybean-derived glycan, microorganism-derived glycan, etc.), Red algae such as glucuronoglycan (for example, gellan gum), glycosaminoglycan (for example, hyaluronic acid, keratan sulfate, etc.), alginic acid and alginates, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan Derived from Natural polymeric polysaccharides and the like, from the viewpoint of not lowering the dispersion stability of the metal oxide fine particles coexisting in the coating solution, preferably, those whose structural unit has no carboxyl group or sulfonic acid group. Such polysaccharides include, for example, pentoses such as L-arabitose, D-ribose, 2-deoxyribose and D-xylose, and hexoses such as D-glucose, D-fructose, D-mannose and D-galactose only. It is preferable that it is a polysaccharide. Specifically, tamarind seed gum known as xyloglucan whose main chain is glucose and side chain is glucose, guar gum known as galactomannan whose main chain is mannose and side chain is glucose, cationized guar gum, Hydroxypropyl guar gum, locust bean gum, tara gum, and arabinogalactan whose main chain is galactose and whose side chain is arabinose can be preferably used. In the present invention, tamarinds, guar gum, cationized guar gum, and hydroxypropyl guar gum are particularly preferable.

  In the present invention, two or more thickening polysaccharides can be used in combination.

<Polymers having reactive functional groups>
Examples of water-soluble polymers applicable to the present invention include polymers having reactive functional groups, such as polyvinylpyrrolidones; polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile. Acrylic resins such as copolymers, vinyl acetate-acrylic acid ester copolymers, acrylic acid-acrylic acid ester copolymers; styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid- Styrene acrylic resin such as acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer; styrene-sodium styrenesulfonate copolymer Polymer, styrene-2-hydroxyethyl acrylate Polymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid Examples thereof include vinyl acetate copolymers such as copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers, and salts thereof. Among these, particularly preferred examples include polyvinylpyrrolidones and copolymers containing the same.

(First metal oxide particles)
In the present invention, the first metal oxide particles applicable to the high refractive index layer are preferably metal oxide particles having a refractive index in the range of 2.0 to 3.0. More specifically, for example, titanium oxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, second oxide oxide. Examples thereof include metal oxide particles such as iron, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. In addition, composite oxide particles composed of a plurality of metals, core / shell type metal oxide particles whose metal structure changes into a core / shell shape, and the like can also be used.

  In order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer is made of metal oxide fine particles having a high refractive index such as titanium and zirconium, that is, titanium oxide fine particles or zirconia oxide fine particles. It is preferable to contain. Among these, titanium oxide is more preferable from the viewpoint of the stability of the coating liquid for forming the high refractive index layer. Among titanium oxides, the rutile type (tetragonal type) has a lower catalytic activity than the anatase type, and the weather resistance of the high refractive index layer and adjacent layers is higher, and the refractive index is higher. Is more preferable.

  When core-shell type metal oxide particles (hereinafter also simply referred to as core-shell particles) are used as the first metal oxide particles in the high refractive index layer, the silicon-containing hydration of the shell layer is used. Due to the effect of suppressing intermixing of the high refractive index layer and the adjacent layer due to the interaction between the oxide and the first water-soluble binder resin, the core / core in which the titanium oxide particles are coated with the silicon-containing hydrated oxide Shell particles are more preferred.

  The aqueous solution containing titanium oxide particles used for the core of the core / shell particle according to the present invention has a pH measured at 25 ° C. in the range of 1.0 to 3.0, and the zeta potential of the titanium particles is positive. It is preferable to use a water-based titanium oxide sol whose surface is made hydrophobic and dispersible in an organic solvent.

  When the content of the first metal oxide particles according to the present invention is in the range of 15 to 80% by mass with respect to the solid content of 100% by mass of the high refractive index layer, the refractive index difference from the low refractive index layer Is preferable from the viewpoint of imparting. Further, it is more preferably in the range of 20 to 77% by mass, and further preferably in the range of 30 to 75% by mass. In addition, content in case metal oxide particles other than the said core-shell particle are contained in a high refractive index layer will not be specifically limited if it is a range which can have the effect of this invention.

  In the present invention, the volume average particle size of the first metal oxide particles applied to the high refractive index layer is preferably 30 nm or less, more preferably in the range of 1 to 30 nm, and 5 to 15 nm. More preferably, it is in the range. A volume average particle size in the range of 1 to 30 nm is preferable from the viewpoint of low haze and excellent visible light transmittance.

  The volume average particle size of the first metal oxide particles according to the present invention refers to a method of observing the particles themselves using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, The particle diameter of 1,000 arbitrary particles is measured by a method of observing a particle image appearing on a cross section or surface with an electron microscope, and each particle has a particle diameter of d1, d2,. N1, n2... Ni... Nk particles of a metal oxide group, where the volume per particle is vi, the volume average particle diameter mv = {Σ (vi. di)} / {Σ (vi)} is the average particle size weighted by the volume.

  Furthermore, the first metal oxide particles according to the present invention are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula (2) is 40% or less. This monodispersity is more preferably 30% or less, and particularly preferably in the range of 0.1 to 20%.

Formula (2)
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 (%)
<Core shell particle>
As the first metal oxide particles applied to the high refractive index layer according to the present invention, “titanium oxide particles surface-treated with a silicon-containing hydrated oxide” is preferably used. The titanium particles may be referred to as “core / shell particles”, “core / shell type metal oxide” or “Si-coated TiO ₂ ”.

In the core / shell particles according to the present invention, the titanium oxide particles are coated with a silicon-containing hydrated oxide, and the average particle size which is preferably a core portion is in the range of 1 to 30 nm, more preferably the average particle size. The surface of the titanium oxide particles having a diameter in the range of 4 to 30 nm is within a range of 3 to 30% by mass of the silicon-containing hydrated oxide as SiO _{2 with} respect to the core titanium oxide. In this way, a shell made of a silicon-containing hydrated oxide is coated.

  That is, in the present invention, by including the core-shell particles, the interaction between the silicon-containing hydrated oxide of the shell layer and the first water-soluble binder resin causes the high refractive index layer and the low refractive index layer to The effect of suppressing the intermixing between the layers and the effect of preventing the deterioration of the binder and choking due to the photocatalytic activity of titanium oxide when titanium oxide is used as the core are exhibited.

In the present invention, the core / shell particles preferably have a silicon-containing hydrated oxide coating amount in the range of 3 to 30% by mass as SiO _{2 with} respect to titanium oxide as a core, more preferably 3 It is in the range of 10 to 10% by mass, and more preferably in the range of 3 to 8% by mass. If the coating amount is 30% by mass or less, a high refractive index layer can be made to have a high refractive index, and if the coating amount is 3% by mass or more, core / shell particle particles can be stably formed. can do.

  Furthermore, in the present invention, the average particle diameter of the core / shell particles is preferably in the range of 1 to 30 nm, more preferably in the range of 5 to 20 nm, and still more preferably in the range of 5 to 15 nm. . If the average particle diameter of the core / shell particles is in the range of 1 to 30 nm, optical properties such as near infrared reflectance, transparency, and haze can be further improved.

  In addition, the average particle diameter as used in the field of this invention means a primary average particle diameter, and can be measured from the electron micrograph by a transmission electron microscope (TEM) etc. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc.

  In addition, when obtaining from an electron microscope, the average particle diameter of primary particles is the particle itself or the particles appearing on the cross section or surface of the refractive index layer is observed with an electron microscope, and the particle diameter of 1000 arbitrary particles is measured. It is obtained as its simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

  As a method for producing core / shell particles applicable to the present invention, a known method can be employed. For example, JP-A-10-158015, JP-A-2000-053421, JP-A-2000-063119. JP, 2000-204301, A patent 4550753 etc. can be referred to.

  In the present invention, the silicon-containing hydrated oxide applied to the core / shell particles may be either a hydrate of an inorganic silicon compound, a hydrolyzate or a condensate of an organosilicon compound. In the present invention, silanol A compound having a group is preferable.

  The high refractive index layer according to the present invention may contain other metal oxide particles in addition to the core / shell particles. When other metal oxide particles are used in combination, various ionic dispersants and protective agents can be used so that the core and shell particles described above do not aggregate in a chargeable manner. Examples of metal oxide particles that can be used in addition to the core / shell particles include titanium dioxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, and yellow lead. Zinc yellow, chromium oxide, ferric oxide, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, tin oxide and the like.

  The core / shell particles according to the present invention may be those in which the entire surface of the titanium oxide particles as the core is coated with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles as the core is silicon-containing. It may be coated with a hydrated oxide.

(Curing agent)
In the present invention, a curing agent can also be used to cure the first water-soluble binder resin applied to the high refractive index layer. The curing agent that can be used together with the first water-soluble binder resin is not particularly limited as long as it causes a curing reaction with the water-soluble binder resin. For example, when polyvinyl alcohol is used as the first water-soluble binder resin, boric acid and its salt are preferable as the curing agent. In addition to boric acid and its salts, known ones can be used, and in general, a compound having a group capable of reacting with polyvinyl alcohol or a compound that promotes the reaction between different groups possessed by polyvinyl alcohol. Select and use. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glioxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5) , -S-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

  Boric acid and salts thereof refer to oxygen acids and salts thereof having a boron atom as a central atom, specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaboron. Examples include acids and their salts.

  Boric acid having a boron atom as a curing agent and a salt thereof may be used as a single aqueous solution or as a mixture of two or more. Particularly preferred is a mixed aqueous solution of boric acid and borax.

  The aqueous solutions of boric acid and borax can be added only in relatively dilute aqueous solutions, respectively, but by mixing both, a concentrated aqueous solution can be obtained and the coating solution can be concentrated. Further, there is an advantage that the pH of the aqueous solution to be added can be controlled relatively freely.

  In the present invention, it is more preferable to use boric acid and a salt thereof, or borax to obtain the effects of the present invention. When boric acid and its salt, or borax are used, metal oxide particles and water-soluble binder resin polyvinyl alcohol OH groups and hydrogen bond network are more easily formed, as a result, high refractive index layer and It is considered that interlayer mixing with the low refractive index layer is suppressed, and preferable near-infrared blocking characteristics are achieved. Especially when a set coating process is used in which a multilayer coating of a high refractive index layer and a low refractive index layer is applied with a wet coater, the film surface temperature of the coating film is once cooled to about 15 ° C., and then the film surface is dried. In this case, the effect can be expressed more preferably.

  The content of the curing agent in the high refractive index layer is preferably in the range of 1 to 10% by mass and in the range of 2 to 6% by mass with respect to 100% by mass of the solid content of the high refractive index layer. It is more preferable.

  In particular, the total amount of the curing agent used when polyvinyl alcohol is used as the first water-soluble binder resin is preferably in the range of 1 to 600 mg per 1 g of polyvinyl alcohol, and in the range of 100 to 600 mg per 1 g of polyvinyl alcohol. More preferred.

(Low refractive index layer)
The low refractive index layer according to the present invention includes a second water-soluble binder resin and second metal oxide particles, and further includes a curing agent, a surface coating component, a particle surface protective agent, a binder resin, a surfactant, Various additives may be included.

  The refractive index of the low refractive index layer according to the present invention is preferably in the range of 1.10 to 1.60, more preferably 1.30 to 1.50.

(Second water-soluble binder resin)
Polyvinyl alcohol is preferably used as the second water-soluble binder resin applied to the low refractive index layer according to the present invention. Furthermore, it is more preferable that polyvinyl alcohol (B) different from the saponification degree of polyvinyl alcohol (A) present in the high refractive index layer is used in the low refractive index layer according to the present invention. In addition, description about polyvinyl alcohol (A) and polyvinyl alcohol (B), such as a preferable weight average molecular weight of 2nd water-soluble binder resin here, is demonstrated by the water-soluble binder resin of the said high refractive index layer. The description is omitted here.

  The content of the second water-soluble binder resin in the low refractive index layer is preferably within the range of 20 to 99.9% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably, it is in the range of mass%.

  As a water-soluble binder resin other than polyvinyl alcohol, which can be applied in the low refractive index layer according to the present invention, any method can be used as long as the low refractive index layer containing the second metal oxide particles can form a coating film. Anything can be used without limitation. However, in consideration of environmental problems and flexibility of the coating film, water-soluble polymers (particularly gelatin, thickening polysaccharides, polymers having reactive functional groups) are preferable. These water-soluble polymers may be used alone or in combination of two or more.

  In the low refractive index layer, the content of other binder resin used in combination with polyvinyl alcohol preferably used as the second water-soluble binder resin is 0 to 10 mass relative to 100 mass% of the solid content of the low refractive index layer. % Can also be used.

  The low refractive index layer of the infrared reflective film of the present invention may contain water-soluble polymers such as celluloses, thickening polysaccharides, and polymers having reactive functional groups. These water-soluble polymers such as celluloses, thickening polysaccharides and polymers having reactive functional groups are the same as the water-soluble polymers described in the high refractive index layer described above. Is omitted.

(Second metal oxide particles)
As the second metal oxide particles applied to the low refractive index layer according to the present invention, silica (silicon dioxide) is preferably used, and specific examples thereof include synthetic amorphous silica and colloidal silica. Of these, acidic colloidal silica sol is more preferably used, and colloidal silica sol dispersed in an organic solvent is more preferably used. Further, in order to further reduce the refractive index, hollow fine particles having pores inside the particles can be used as the second metal oxide particles applied to the low refractive index layer, particularly silica (silicon dioxide). The hollow fine particles are preferred.

  The second metal oxide particles (preferably silicon dioxide) applied to the low refractive index layer preferably have an average particle size in the range of 3 to 100 nm. The average particle diameter of primary particles of silicon dioxide dispersed in a primary particle state (particle diameter in a dispersion state before coating) is more preferably in the range of 3 to 50 nm, and in the range of 3 to 40 nm. Is more preferably 3 to 20 nm, and most preferably within a range of 4 to 10 nm. Moreover, as an average particle diameter of secondary particle | grains, it is preferable from a viewpoint with few hazes and being excellent in visible light permeability that it is 30 nm or less.

  The average particle size of the metal oxide particles applied to the low refractive index layer is determined by observing the particles themselves or the particles appearing on the cross section or surface of the refractive index layer with an electron microscope and measuring the particle size of 1000 arbitrary particles. The simple average value (number average) is obtained. Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

  The colloidal silica used in the present invention is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A-57-14091, JP-A-60-219083, JP-A-60-219084, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 No. 5, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142. , JP-A-7-179029, JP-A-7-137431, and International Publication No. 94/26530 A.

  Such colloidal silica may be a synthetic product or a commercially available product. The surface of the colloidal silica may be cation-modified, or may be treated with Al, Ca, Mg, Ba or the like.

  Hollow particles can also be used as the second metal oxide particles applied to the low refractive index layer. When hollow particles are used, the average particle pore size is preferably in the range of 3 to 70 nm, more preferably in the range of 5 to 50 nm, and still more preferably in the range of 5 to 45 nm. The average particle pore diameter of the hollow particles is the average value of the inner diameters of the hollow particles. In the present invention, when the average particle pore diameter of the hollow particles is in the above range, the refractive index of the low refractive index layer is sufficiently lowered. The average particle diameter is 50 or more at random, which can be observed as an ellipse in a circular, elliptical or substantially circular shape by electron microscope observation. Is obtained. The average particle hole diameter means the minimum distance among the distances between the outer edges of the hole diameter that can be observed as a circle, ellipse, substantially circle or ellipse, between two parallel lines.

  The second metal oxide particles according to the present invention may be surface-coated with a surface coating component. In particular, when using metal oxide particles that are not core / shell as the first metal oxide particles according to the present invention, the surface of the second metal oxide particles is coated with a surface coating component such as polyaluminum chloride. It becomes difficult to aggregate with the first metal oxide particles.

  The content of the second metal oxide particles in the low refractive index layer is preferably in the range of 0.1 to 70% by mass, and 30 to 70% by mass with respect to 100% by mass of the solid content of the low refractive index layer. % Is more preferable, and a range of 45 to 65% by mass is even more preferable.

(Curing agent)
Similarly to the high refractive index layer, the low refractive index layer according to the present invention can further contain a curing agent. There is no particular limitation as long as it causes a curing reaction with the second water-soluble binder resin contained in the low refractive index layer. In particular, boric acid and its salts and / or borax are preferred as the curing agent when polyvinyl alcohol is used as the second water-soluble binder resin applied to the low refractive index layer. In addition to boric acid and its salts, known ones can be used.

  The content of the curing agent in the low refractive index layer is preferably in the range of 1 to 10% by mass and in the range of 2 to 6% by mass with respect to 100% by mass of the solid content of the low refractive index layer. It is more preferable.

  In particular, the total amount of the curing agent used when polyvinyl alcohol is used as the second water-soluble binder resin is preferably in the range of 1 to 600 mg per 1 g of polyvinyl alcohol, and in the range of 100 to 600 mg per 1 g of polyvinyl alcohol. More preferred.

  Moreover, since the specific example of a hardening | curing agent is the same as that of the high refractive index layer mentioned above, description is abbreviate | omitted here.

[Other additives for each refractive index layer]
In the high refractive index layer and the low refractive index layer according to the present invention, various additives can be used as necessary. Moreover, it is preferable that content of the additive in a high refractive index layer exists in the range of 0.01-20 mass% with respect to 100 mass% of solid content of a high refractive index layer. Examples of such additives are described below.

(Surfactant)
In the present invention, at least one of the high refractive index layer and the low refractive index layer may further contain a surfactant. As the surfactant, any of zwitterionic, cationic, anionic, and nonionic types can be used. More preferably, a betaine zwitterionic surfactant, a quaternary ammonium salt cationic surfactant, a dialkylsulfosuccinate anionic surfactant, an acetylene glycol nonionic surfactant, or a fluorine cationic interface An activator is preferred.

  As the addition amount of the surfactant according to the present invention, when the total mass of the coating solution for forming a high refractive index layer or the coating solution for forming a low refractive index layer is 100% by mass, 0.005 to 0.30% by mass. Is preferably in the range of 0.01 to 0.10% by mass.

(amino acid)
In the present invention, the high refractive index layer or the low refractive index layer may contain an amino acid having an isoelectric point of 6.5 or less. By including an amino acid, the dispersibility of the metal oxide particles in the high refractive index layer or the low refractive index layer can be improved.

  An amino acid here is a compound having an amino group and a carboxyl group in the same molecule, and may be any type of amino acid such as α-, β-, and γ-. Some amino acids have optical isomers, but in the present invention, there is no difference in effect due to optical isomers, and any isomer can be used alone or in racemic form.

  For a detailed explanation of amino acids, reference can be made to the descriptions on pages 268 to 270 of the Chemical Dictionary 1 Reprint (Kyoritsu Shuppan; issued in 1960).

  Specific examples of preferable amino acids include aspartic acid, glutamic acid, glycine, serine, and the like, and glycine and serine are particularly preferable.

  The isoelectric point of an amino acid is that an amino acid balances positive and negative charges in a molecule at a specific pH, and the overall charge is 0. Therefore, this pH value is called an isoelectric point. The isoelectric point of each amino acid can be determined by isoelectric focusing at a low ionic strength.

(Emulsion resin)
The high refractive index layer or the low refractive index layer according to the present invention may further contain an emulsion resin. By including the emulsion resin, the flexibility of the film is increased and the workability such as sticking to glass is improved.

  The emulsion resin is a resin in which fine resin particles having an average particle diameter of about 0.01 to 2.0 μm, for example, are dispersed in an emulsion state in an aqueous medium, and an oil-soluble monomer having a high hydroxyl group. Obtained by emulsion polymerization using a dispersing agent such as a molecular dispersing agent. There is no fundamental difference in the polymer component of the resulting emulsion resin depending on the type of dispersant used. Examples of the dispersant used in the polymerization of the emulsion include polyoxyethylene nonylphenyl ether in addition to low molecular weight dispersants such as alkylsulfonate, alkylbenzenesulfonate, diethylamine, ethylenediamine, and quaternary ammonium salt. , Polymer dispersing agents such as polyoxyethylene lauryl ether, hydroxyethyl cellulose, and polyvinylpyrrolidone. When emulsion polymerization is performed using a polymer dispersant having a hydroxyl group, the presence of a hydroxyl group is estimated on at least the surface of fine particles, and the emulsion resin polymerized using another dispersant is different from the chemical and physical properties of the emulsion. Different.

  The polymer dispersant containing a hydroxyl group is a polymer dispersant having a weight average molecular weight of 10,000 or more, and has a side chain or a terminal substituted with a hydroxyl group, such as polyacrylic acid soda and polyacrylamide. Examples include acrylic polymers in which 2-ethylhexyl acrylate is copolymerized, and polyethers such as polyethylene glycol and polypropylene glycol.

(Lithium compound)
In the present invention, at least one of the high refractive index layer and the low refractive index layer may further contain a lithium compound. The coating liquid for forming a high refractive index layer or the coating liquid for forming a low refractive index layer containing the lithium compound becomes easier to control the viscosity, and as a result, the production stability of the infrared reflective film of the present invention is further improved.

The lithium compound applicable to the present invention is not particularly limited. For example, lithium carbonate, lithium sulfate, lithium nitrate, lithium acetate, lithium orotate, lithium citrate, lithium molybdate, lithium chloride, lithium hydride, water Lithium oxide, lithium bromide, lithium fluoride, lithium iodide, lithium stearate, lithium phosphate, lithium hexafluorophosphate, lithium aluminum hydride, lithium hydride triethylborate, lithium triethoxyaluminum hydride, tantalate Examples thereof include lithium, lithium hypochlorite, lithium oxide, lithium carbide, lithium nitride, lithium niobate, lithium sulfide, lithium borate, LiBF ₄ , LiClO ₄ , LiPF ₄ , LiCF ₃ SO _{3 and the} like. These lithium compounds can be used alone or in combination of two or more.

  Among these, lithium hydroxide is preferable from the viewpoint that the effects of the present invention can be further exhibited.

  The addition amount of the lithium compound is preferably in the range of 0.005 to 0.05 g, more preferably in the range of 0.01 to 0.03 g, per 1 g of metal oxide particles present in each refractive index layer. is there.

(Other additives)
Other additives applicable to the high refractive index layer and the low refractive index layer according to the present invention are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, JP-A-57- No. 878989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, JP-A-3-13376, etc. Fluorescence enhancement described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871, and JP-A-4-219266 Whitening agent, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents, diethylene glycol and other lubricants, preservatives, antifungal agents Various known additives such as antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, thinning agents, lubricants, infrared absorbers, dyes, pigments, etc. Can be mentioned.

[Method of forming infrared reflective layer group]
The method for forming an infrared reflective layer unit according to the present invention is preferably formed by applying a wet coating method. Furthermore, the first water-soluble binder resin and the first metal oxide particles are formed on the transparent substrate. A production method including a step of wet-coating a coating solution for forming a high refractive index layer containing, and a coating solution for forming a low refractive index layer containing a second water-soluble binder resin and second metal oxide particles is preferable.

  The wet coating method is not particularly limited, and for example, roll coating method, rod bar coating method, air knife coating method, spray coating method, slide curtain coating method, or US Pat. No. 2,761,419, US patent. Examples thereof include a slide hopper coating method and an extrusion coating method described in Japanese Patent No. 2,761,791. In addition, as a method of applying a plurality of layers in a multilayer manner, a sequential multilayer application method or a simultaneous multilayer application method may be used.

  Hereinafter, the simultaneous multilayer coating method by the slide hopper coating method, which is a preferred manufacturing method (coating method) of the present invention, will be described in detail.

(solvent)
The solvent that can be applied to prepare the coating solution for forming a high refractive index layer and the coating solution for forming a low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable.

  Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, diethyl ether and propylene. Examples thereof include ethers such as glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone. These organic solvents may be used alone or in combination of two or more.

  In view of environmental aspects and ease of operation, the solvent for each refractive index layer forming coating solution is particularly preferably water alone or a mixed solvent of water and methanol, ethanol or ethyl acetate.

(Concentration of coating solution)
The concentration of the water-soluble binder resin in the coating solution for forming a high refractive index layer and the coating solution for forming a low refractive index layer is preferably in the range of 1 to 10% by mass. Moreover, it is preferable that the density | concentration of the metal oxide particle in the coating liquid for high refractive index layer formation and the coating liquid for low refractive index layer formation exists in the range of 1-50 mass%, respectively.

(Method for preparing coating solution)
The method for preparing the coating solution for forming the high refractive index layer and the coating solution for forming the low refractive index layer is not particularly limited. For example, the water-soluble binder resin, the metal oxide particles, and other additions added as necessary. The method of adding an agent and stirring and mixing is mentioned. At this time, the order of addition of the water-soluble binder resin, metal oxide particles, and other additives used as necessary is not particularly limited, and each component may be added and mixed sequentially while stirring, or stirring. However, they may be added and mixed at once. If necessary, it is further adjusted to an appropriate viscosity using a solvent.

  In the present invention, it is preferable to form a high refractive index layer using an aqueous high refractive index coating solution prepared by adding and dispersing core / shell particles. At this time, the core / shell particles are added to the coating solution for a high refractive index layer as a sol having a pH measured at 25 ° C. in the range of 5.0 to 7.5 and a negative zeta potential of the particles. It is preferable to prepare it.

(Viscosity of coating solution)
The viscosity at 40 to 45 ° C. assuming the coating step of the coating solution for forming the high refractive index layer and the coating solution for forming the low refractive index layer when performing simultaneous multilayer coating by the slide hopper coating method is 5 to 150 mPa · s, respectively. Within the range is preferable, and within the range of 10 to 100 mPa · s is more preferable. Moreover, the viscosity at 40 to 45 ° C. of the coating solution for forming a high refractive index layer and the coating solution for forming a low refractive index layer when performing simultaneous multilayer coating by the slide curtain coating method is within a range of 5 to 1200 mPa · s, respectively. Is preferable, and within the range of 25 to 500 mPa · s is more preferable.

  Further, the viscosity at 15 ° C. assuming the setting step of the coating solution for forming the high refractive index layer and the coating solution for forming the low refractive index layer is preferably 100 mPa · s or more, and more preferably in the range of 100 to 30000 mPa · s. The range of 3000 to 30000 mPa · s is more preferable, and the range of 10000 to 30000 mPa · s is particularly preferable.

(Coating and drying method)
The coating and drying method is not particularly limited, but the coating solution for forming a high refractive index layer and the coating solution for forming a low refractive index layer are heated to 30 ° C. or higher to form a coating solution for forming a high refractive index layer on the substrate. After the simultaneous multilayer coating of the coating solution for forming the low refractive index layer, the temperature of the formed coating film is preferably cooled (set) preferably to 1 to 15 ° C. and then dried at 10 ° C. or higher. More preferable drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the uniformity improvement of the formed coating film.

  The wet film thickness (wet film thickness) at the time of application of the coating solution for forming the high refractive index layer and the coating liquid for forming the low refractive index layer is a preferable dry thickness (dry film thickness) as described above. What is necessary is just to apply | coat.

  “Set” as used herein refers to a step of increasing the viscosity of the coating composition by means such as lowering the temperature by applying it to the coating film on which cold air or the like is formed, and reducing the fluidity of substances in each layer and in each layer. Means that. A state in which the cold air is applied to the coating film from the surface and the finger is pressed against the surface of the coating film is defined as a set completion state.

  After application, the time from application of cold air to completion of setting (setting time) is preferably within 5 minutes, and preferably within 2 minutes. Further, the lower limit time is not particularly limited, but it is preferable to take 45 seconds or more. If the set time is too short, mixing of the components in the layer may be insufficient. On the other hand, if the set time is too long, interlayer diffusion of the metal oxide particles proceeds, and the refractive index difference between the high refractive index layer and the low refractive index layer may be insufficient. In addition, if the high elasticity of the heat ray blocking film unit between the high refractive index layer and the low refractive index layer occurs quickly, the setting step may not be provided.

  The set time is adjusted by adjusting the concentration of the water-soluble binder resin and the metal oxide particles, and adding other components such as various known gelling agents such as gelatin, pectin, agar, carrageenan and gellan gum. Can be adjusted.

  The temperature of the cold air is preferably in the range of 0 to 25 ° C, and more preferably in the range of 5 to 10 ° C. Moreover, although the time for which a coating film is exposed to cold wind is based also on the conveyance speed of a coating film, it is preferable to exist in the range for 10 to 120 seconds.

[Other constituent layers of the infrared reflection layer unit U]
In the infrared reflective layer unit U according to the present invention, in addition to the infrared reflective layer group ML of the high refractive index layer and the low refractive index layer described above on the transparent substrate, for the purpose of adding further functions, for example, Conductive layer, antistatic layer, gas barrier layer, easy adhesion layer (adhesion layer), antifouling layer, deodorant layer, droplet layer, easy slip layer, hard coat layer, wear resistant layer, antireflection layer, electromagnetic wave shield Other than the infrared reflective layer group ML such as a layer, an ultraviolet absorption layer, an infrared absorption layer, a printing layer, a fluorescent light emitting layer, a hologram layer, a release layer, an adhesive layer, an adhesion layer, and a high refractive index layer and a low refractive index layer according to the present invention May have functional layers such as an infrared cut layer (metal layer, liquid crystal layer) and a colored layer (visible light absorbing layer). Hereinafter, an infrared absorption layer and a heat insulation layer which are preferable functional layers will be described.

(Infrared absorbing layer)
The infrared reflection layer unit U according to the present invention may further include an infrared absorption layer. The infrared absorbing layer is laminated at an arbitrary position, but in order to obtain the heat shielding effect of the laminated glass of the present invention more efficiently, it is laminated below the infrared reflecting layer group ML when viewed from the incident light side. It is more preferable that the transparent resin film is laminated on the surface opposite to the surface on which the infrared reflective layer group ML is laminated. Moreover, even if it contains an infrared absorber in another layer, for example, a hard coat layer, it functions as an infrared absorption layer.

  In the present invention, the layer thickness per infrared absorbing layer is preferably in the range of 0.1 to 50 μm, and more preferably in the range of 1 to 20 μm. If the layer thickness is 0.1 μm or more, the infrared absorption ability tends to be improved, while if it is 50 μm or less, the crack resistance of the formed infrared absorption layer is improved.

  Although it does not restrict | limit especially as a material which comprises an infrared rays absorption layer, For example, an ultraviolet curable resin, a photoinitiator, an infrared absorber, etc. are mentioned.

  The ultraviolet curable resin is more excellent in hardness and smoothness than other resins, and is also advantageous from the viewpoint of dispersibility of ITO, antimony-doped tin oxide (ATO), and thermally conductive metal oxide particles. The ultraviolet curable resin can be used without particular limitation as long as it is a resin that forms a transparent layer by curing with ultraviolet rays, and examples thereof include silicone resins, epoxy resins, vinyl ester resins, acrylic resins, and allyl ester resins. More preferred is an acrylic resin from the viewpoint of hardness, smoothness and transparency.

  The acrylic resin is a reactive silica particle in which a photosensitive group having photopolymerization reactivity is introduced on its surface as described in International Publication No. 2008/035669 from the viewpoint of hardness, smoothness, and transparency. (Hereinafter also simply referred to as “reactive silica particles”). Here, examples of the photopolymerizable photosensitive group include a polymerizable unsaturated group represented by a (meth) acryloyloxy group. The ultraviolet curable resin contains a photopolymerizable photosensitive group introduced on the surface of the reactive silica particles and a compound capable of photopolymerization, for example, an organic compound having a polymerizable unsaturated group. There may be. In addition, the polymerizable unsaturated group-modified hydrolyzable silane is chemically bonded to the silica particles by generating a silyloxy group by a hydrolysis reaction of the hydrolyzable silyl group. It can be used as reactive silica particles. Here, the average particle diameter of the reactive silica particles is preferably in the range of 0.001 to 0.1 μm. By setting the average particle diameter in such a range, transparency, smoothness, and hardness can be satisfied in a well-balanced manner.

  As a photoinitiator, a well-known thing can be used, It can use individually or in combination of 2 or more types.

Inorganic infrared absorbers contained in the infrared absorbing layer include tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and antimony from the viewpoints of visible light transmittance, infrared absorptivity, dispersibility in the resin, and the like. Zinc acid, lanthanum hexaboride (LaB ₆ ), cesium-containing tungsten oxide (Cs _0.33 WO ₃ ) and the like are preferable.

  In the infrared absorption layer, other infrared absorbers such as metal oxide particles other than those described above, organic infrared absorbers, metal complexes and the like may be included within the scope of the effects of the present invention. Specific examples of such other infrared absorbers include diimonium compounds, aluminum compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds, triphenyl compounds. Examples include phenylmethane compounds.

  The method for forming the infrared absorbing layer is not particularly limited. For example, the infrared absorbing layer forming coating solution containing each of the above components is prepared, and then the coating solution is applied using a wire bar and dried. And a wet coating method.

(Insulation layer)
In the present invention, a heat insulating layer having voids (hereinafter also simply referred to as a heat insulating layer) can be formed on either surface side of the transparent substrate. By providing the heat insulating layer, it is possible to reduce the risk of so-called thermal cracking in which the glass is damaged by light irradiation. Furthermore, the heat shielding effect of the laminated glass of the present invention can be further improved.

  The heat insulating layer according to the present invention preferably has a thermal conductivity of 0.001 to 0.2 W / (m · K), more preferably 0.005 to 0.15 W / (m · K). Within range. When the thermal conductivity is 0.001 W / (m · K) or more, slight heat transfer and thermal diffusion occur, and damage such as swelling, peeling, and discoloration of the film hardly occurs. Moreover, if it is 0.2 W / (m * K) or less, a heat transfer and thermal diffusion can be suppressed, the heat conduction to glass can be suppressed effectively, and a glass thermal crack becomes difficult to occur.

  The thermal conductivity can be measured using a hot-wire probe type thermal conductivity measuring device, for example, QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd.

  The porosity of the heat insulation layer according to the present invention is preferably in the range of 30 to 95%, more preferably in the range of 60 to 95%. If the porosity is 30% or more, heat insulating performance is exhibited, and thermal cracking of the glass hardly occurs. Moreover, if the porosity is 95% or less, the layer structure strength can be maintained to such an extent that the structure does not collapse even during handling.

  The material for forming the heat insulating layer is not particularly limited, and examples thereof include a combination of inorganic oxide particles and a resin binder, or a foamed resin.

A known material can be used as the inorganic oxide particles. Specifically, for example, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), zeolite, titanium oxide (TiO ₂ ), barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ). ₃ ), calcium titanate (CaTiO ₃ ), aluminum borate, iron oxide, calcium carbonate, barium carbonate, lead oxide, tin oxide, cerium oxide, calcium oxide, trimanganese tetroxide, magnesium oxide, niobium oxide, tantalum oxide, Tungsten oxide, antimony oxide, aluminum phosphate, calcium silicate, zirconium silicate, ITO, titanium silicate, mesoporous silica (FSM-16, MCM41, etc.), montmorillonite, saponite, vermiculite, hydrotalcite, potassium Examples include orinite, kanemite, isralite, magadiite, and kenyaite. These may be used alone or in combination of two or more. Furthermore, these composite oxides can also be preferably used. Among these, neutral to acidic inorganic oxide particles are preferable from the viewpoint of the strength of the heat insulating layer. Specifically, zirconium oxide, montmorillonite, saponite, vermiculite, hydrotalcite, kaolinite, kanemite, tin oxide, tungsten oxide, titanium oxide, aluminum phosphate, silica, zinc oxide, or alumina are preferable, and more preferable. Are silica particles or alumina particles. This is because silica particles and alumina particles are industrially inexpensive and easily available, and since the surface has a reactive hydroxy group, it is relatively easy to modify the surface with a crosslinkable functional group. .

  The average particle size of the inorganic oxide particles is preferably in the range of 1 to 200 nm. If the average particle size is 1 nm or more, the porosity tends to increase and the heat insulating property tends to be improved, and if the average particle size is 200 nm or less, the film strength of the heat insulating layer tends to improve.

  The inorganic oxide particles contained in the heat insulating layer may be hollow particles from the viewpoint of easily controlling the pore diameter of the voids and the thickness of the outer shell of the heat insulating layer structure. As hollow particles to be used, the template surface is coated with an inorganic oxide using a sol-gel solution such as a metal alkoxide or a silane coupling agent in which a template of inorganic nanoparticles having a predetermined particle size is dispersed, or a reactive resin monomer solution. After that, it can be obtained by a method of dissolving the template inside and making it hollow. The hollow particles may have a structure in which a part of the outer casing is not only closed but also partially open. In addition, as materials used for the outer casing, silica, metal oxides, organic resin materials, etc. can be used without limitation, but in order to ensure the mechanical strength of the heat insulating layer, silica or organic modified silica is formed. It is preferable to use a silane coupling agent.

  The average pore diameter of the hollow particles is preferably 80 nm or less, and more preferably 50 nm or less in order to ensure heat insulation and transparency. The average thickness of the outer casing is preferably in the range of 1 to 7 nm, more preferably in the range of 1 to 5 nm. If the thickness of the outer sheath is 7 nm or less, the transparency of the heat insulating layer tends to be improved, and if it is 1 nm or more, the mechanical strength of the heat insulating layer tends to be increased.

  The average particle diameter of these inorganic oxide particles is the volume average value of the diameter (sphere-converted particle diameter) when each particle is converted to a sphere having the same volume, and this value can be obtained by observation with an electron microscope. That is, from observation of the inorganic oxide particles with an electron microscope, 200 or more inorganic oxide fine particles in a certain visual field were measured, the spherical equivalent particle diameter of each particle was obtained, and the average value was obtained. is there.

  In the present invention, inorganic oxide particles whose surface is modified with a silane coupling agent or the like can also be used. The surface modifying group is not particularly limited, but a crosslinkable functional group capable of crosslinking with a nitrogen-containing aromatic polymer having a crosslinkable functional group at the terminal is preferably used. Here, as the crosslinkable functional group, a group having a carbon-carbon unsaturated bond such as a vinyl group, an acrylic group, a methacryl group or an allyl group, a cyclic ether group such as an epoxy group or an oxetane group, an isocyanate group, a hydroxy group, or a carboxy group. Group and the like.

  Although content in particular of the inorganic oxide particle in a heat insulation layer is not restrict | limited, It is preferable to exist in the range of 10-95 mass% with respect to the total mass of a heat insulation layer, and within the range of 50-90 mass%. More preferably. When the content of the inorganic oxide particles is 10% by mass or more, the porosity is increased and the heat insulating property tends to be improved, and when it is 95% by mass or less, the mechanical strength of the heat insulating layer tends to be improved.

  When the heat insulating layer contains inorganic oxide particles, it is preferable to contain a small amount of a resin binder from the viewpoints of coating film flexibility and void formation.

  Applicable resin binders include thermoplastic resins and polymers having rubber elasticity. Specifically, for example, starch, carboxymethylcellulose, cellulose, diacetylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium alginate Water-soluble resins such as polyacrylic acid, sodium polyacrylate, polyvinylphenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylonitrile, polyacrylamide, polyhydroxy (meth) acrylate, styrene-maleic acid copolymer, poly Vinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene (Meth) acrylic such as rholide-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate, etc. (Meth) acrylic acid ester copolymer containing acid ester, (meth) acrylic acid ester-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer, acrylonitrile -Butadiene copolymer, polybutadiene, neoprene rubber, fluoro rubber, polyethylene oxide, polyester polyurethane resin, polyether polyurethane resin, polycarbonate poly Urethane resins, polyester resins, phenolic resins, emulsion (latex) or suspension such as an epoxy resin. Of these, water-soluble resins are preferable, and polyvinyl alcohol is more preferably used.

  Examples of the foamed resin used as the material for the heat insulating layer include foams such as polyolefins such as polyurethane, polystyrene, polyethylene, and polypropylene, phenol resins, polyvinyl chloride, urea resins, polyimides, and melamine resins. These may be used alone or in combination of two or more. Among these, foamed polystyrene or foamed polyurethane is preferable from the viewpoint of moldability.

  Moreover, you may use a crosslinking agent for a heat insulation layer from a viewpoint of raising film | membrane intensity | strength more. The crosslinking agent is roughly classified into an inorganic type and an organic type. In the present invention, either of them can provide a sufficient effect. These crosslinking agents can be used alone or in combination of two or more.

  In the present invention, the method for forming the heat insulating layer is not particularly limited, but when the heat insulating layer contains inorganic oxide particles and a resin binder, a wet coating method is preferable. Specifically, it can be formed by mixing inorganic oxide particles, a resin binder, and, if necessary, a crosslinking agent with a solvent to prepare a coating solution, and then coating and drying on a substrate.

  As a coating method using a coating liquid, the method is not particularly limited as long as it is a method that can be applied substantially uniformly to a desired thickness. For example, a screen printing method, a bar coating method, a roll coating method, a reverse coating method, a gravure printing method, a doctor blade method, a die coating method, and the like can be given. The coating method can be properly used as necessary, such as continuous coating, intermittent coating, and stripe coating.

[Polyvinyl acetal resin film]
In the infrared reflective film of the present invention, the infrared reflective layer unit described above has a polyvinyl acetal resin film on both surfaces, and the polyvinyl acetal resin film according to the present invention is a polyvinyl butyral film. Is preferred.

  The polyvinyl acetal resin according to the present invention is not particularly limited as long as it is a polyvinyl acetal resin obtained by acetalizing a polyvinyl alcohol (hereinafter abbreviated as PVA) resin with an aldehyde.

  The PVA resin is usually obtained by saponifying a polyvinyl acetate resin, and a PVA resin having a saponification degree of 80 to 99.8 mol% is generally used. In addition, the average molecular weight and molecular weight distribution of the polyvinyl acetal resin used in the present invention are not particularly limited. However, in consideration of moldability (film forming property) and physical properties, the average polymerization as a PVA resin as a raw material It is preferable to use a PVA resin having a degree of 200 to 3000, particularly preferably a PVA resin having an average degree of polymerization of 500 to 2000.

  If the average degree of polymerization of the PVA resin is 200 or more, the strength of the obtained polyvinyl acetal resin film is sufficient, and the laminated glass produced using this polyvinyl acetal resin film has the penetration resistance, impact energy absorption, etc. It will be enough. Moreover, if the average degree of polymerization of the PVA resin is 3000 or less, the moldability (film forming property) of the obtained polyvinyl acetal resin film is improved, and the rigidity of the polyvinyl acetal resin film is within an appropriate range. Good workability at the time.

  As the aldehyde applied to the acetalization, aldehydes having 1 to 10 carbon atoms in the substituent are preferable, and specific examples thereof are not particularly limited. For example, formaldehyde, acetaldehyde, propionaldehyde, n -Butyraldehyde, isobutyraldehyde, n-valeraldehyde, n-hexyl aldehyde, 2-ethyl butyraldehyde, benzaldehyde, n-octyl aldehyde, n-nonyl aldehyde, n-decyl aldehyde, etc., among others, n-butyl Aldehyde, n-valeraldehyde, n-hexylaldehyde and the like are preferably used, and n-butyraldehyde having a substituent having 4 carbon atoms is particularly preferably used. These aldehydes may be appropriately selected according to the performance required for the obtained polyvinyl acetal resin. Moreover, these aldehydes may be used independently and 2 or more types may be used together.

  The polyvinyl acetal resin used in the present invention may be a mixed polyvinyl acetal resin in which two or more kinds of polyvinyl acetal resins are mixed, or a co-polyvinyl acetal using two or more kinds of aldehydes at the time of acetalization. A resin may be used.

  The polyvinyl acetal resin used in the present invention is not particularly limited, but the acetalization degree is preferably in the range of 40 to 85 mol%, more preferably in the range of 60 to 75 mol%. Is within.

  In the infrared reflective film of the present invention, among the polyvinyl acetal resins described above, a polyvinyl butyral (hereinafter also referred to as PVB) resin obtained by butyralizing (acetalizing) a PVA resin with n-butyraldehyde is used. Particularly preferably used.

  A plasticizer is usually added to the polyvinyl acetal resin layer.

  The applicable plasticizer may be a conventionally known plasticizer used for plasticizing a polyvinyl acetal resin, and is not particularly limited. For example, a monobasic organic acid ester plasticizer, Examples thereof include organic acid ester plasticizers such as basic organic acid plasticizers, phosphoric acid plasticizers such as organic phosphoric acid plasticizers, and organic phosphorous acid plasticizers.

  The monobasic organic acid ester plasticizer is not particularly limited, and examples thereof include glycols such as triethylene glycol, tetraethylene glycol, and tripropylene glycol, butyric acid, isobutyric acid, caproic acid, and 2-ethylbutyric acid. , Glycol esters obtained by reaction with monobasic organic acids such as heptylic acid, n-octylic acid, 2-ethylhexylic acid, pelargonic acid (n-nonyl acid), decyl acid, and the like. Suitable monobasic organic acid esters of triethylene glycol such as ethylene glycol dicaproate, triethylene glycol di-2-ethylbutyrate, triethylene glycol di-n-octylate, triethylene glycol di-2-ethylhexyl ester Used for.

  Although it does not specifically limit as a polybasic organic acid ester plasticizer, For example, polybasic, such as a C4-C8 linear or branched alcohol, adipic acid, sebacic acid, azelaic acid Examples thereof include esters obtained by reaction with volatile organic acids, among which dibutyl sebacic acid ester, dioctyl azelaic acid ester, dibutyl carbitol adipic acid ester and the like are preferably used.

  The phosphate plasticizer is not particularly limited, and examples thereof include tributoxyethyl phosphate, isodecylphenyl phosphate, triisopropyl phosphate, and the like.

  In the infrared reflective film of the present invention, among the plasticizers, for example, triethylene glycol dicaproate, triethylene glycol di-2-ethylbutyrate, triethylene glycol di-n-octylate, triethylene glycol diester. 2-ethylhexyl acid ester and the like are particularly preferably used. These plasticizers may be appropriately selected according to the type of the polyvinyl acetal resin in consideration of the compatibility with the polyvinyl acetal resin. Moreover, these plasticizers may be used independently and 2 or more types may be used together.

  The amount of plasticizer added to the polyvinyl acetal resin varies depending on the average degree of polymerization, the degree of acetalization, the amount of residual acetyl groups, etc. of the polyvinyl acetal resin, and is not particularly limited, but 100 parts by mass of the polyvinyl acetal resin. On the other hand, the plasticizer is preferably in the range of 20 to 100 parts by mass, more preferably in the range of 30 to 60 parts by mass.

  If the addition amount of the plasticizer with respect to 100 parts by mass of the polyvinyl acetal resin is 20 parts by mass or more, plasticization of the polyvinyl acetal resin is sufficient, and the ease of molding (film formation) is improved. Moreover, if the addition amount of the plasticizer with respect to 100 parts by mass of the polyvinyl acetal resin is 100 parts by mass or less, bleeding out of the plasticizer can be suppressed, and the transparency and adhesiveness of the polyvinyl acetal resin film can be maintained. Occurrence of optical distortion of the laminated glass when bonded to the material can be prevented.

  In the polyvinyl acetal resin according to the present invention, an antioxidant (deterioration inhibitor), a heat stabilizer, a light stabilizer, an ultraviolet absorber, an adhesive force are included as long as the achievement of the object of the present invention is not hindered. Various additives such as a regulator, a moisture-proofing agent, a lubricant, a coloring agent, an infrared reflecting agent, an infrared absorbing agent, an antistatic agent, and a flame retardant may be added.

  Examples of the infrared absorber include the same materials as the infrared absorber applicable to the above-described infrared absorbing layer. For example, organic infrared such as cyanine compound, phthalocyanine compound, and chlorine dioxide of phenylenediaminium. Examples thereof include inorganic conductive near-infrared absorbers such as absorbers, transparent conductive oxides such as ITO (indium tin oxide) and ATO (antimony-doped tin oxide), zinc oxide, indium oxide, and tin oxide.

  The film thickness of the polyvinyl acetal-based resin film according to the present invention is not particularly limited, but practically 100 to 1000 μm is considered in consideration of the minimum penetration resistance and economical efficiency required for laminated glass. In the range of 100 to 750 μm, more preferably in the range of 200 to 500 μm, still more preferably in the range of 300 to 400 μm, and particularly preferably in the range of 350 to 450 μm. Within the range, the infrared reflective film of the present invention has a total of two layers of these polyvinyl acetal resin films on both sides.

[Infrared reflective film manufacturing method]
The manufacturing method of the infrared reflective film of this invention is characterized by bonding and manufacturing a polyvinyl acetal type-resin film | membrane on both surfaces of the infrared reflective layer unit demonstrated above, respectively.

  As a specific manufacturing method, on the transparent resin film 2 which is a transparent substrate, a single layer or a high refractive index layer and a low refractive index layer were alternately laminated as shown in FIGS. The infrared reflection layer group ML (MLa and MLb) is applied by a wet application method to form the infrared reflection layer unit U.

  Next, the polyvinyl acetal resin films 3A and 3B are bonded to both surfaces of the formed infrared reflective layer unit U. As a pasting method, for example, the infrared reflective film 1 formed by pasting the polyvinyl acetal resin films 3A and 3B is used in a range of 1 to 50 MPa using a nip roller or the like constituted by a pair of opposed rollers. It is preferable to manufacture by bonding with the internal pressure. At the time of pasting, you may heat-process simultaneously with pressurization as needed.

  Subsequently, the produced infrared reflective film may be laminated in a roll shape as it is, or may be laminated in a roll shape after further providing a separate film on the polyvinyl acetal resin film.

<Method for producing laminated glass>
The method for producing a laminated glass of the present invention is produced by sandwiching the infrared reflective film 1 in which the polyvinyl acetal resin films 3A and 3B are bonded to both surfaces of the infrared reflective layer unit U between two glass substrates.

  That is, the laminated glass produced by the method for producing laminated glass according to the present invention comprises, from the incident light side, one glass substrate, the infrared reflective layer film 1 (first polyvinyl acetal resin film 3A / infrared reflective layer unit U). (First infrared reflection layer group MLa / transparent substrate 2 / (second infrared reflection group MLb) / second polyvinyl acetal resin film 3B) and the other glass substrate are arranged in this order. The two glass substrates may be the same type of glass substrate or different types of glass substrates.

  The laminated glass according to the present invention may be a flat laminated glass or a laminated glass using a curved glass substrate used for a windshield of a car.

  In particular, when the laminated glass according to the present invention is used as a window glass of a car, the visible light transmittance is preferably 70% or more. The visible light transmittance can be measured by using, for example, a spectrophotometer (U-4000 type, manufactured by Hitachi, Ltd.), JIS R3106 (1998) “Test of transmittance, reflectance, and solar heat acquisition rate of plate glass”. It can be measured according to “Method”.

  The solar heat gain of the laminated glass according to the present invention is preferably 60% or less, and more preferably 55% or less. If it is this range, the heat ray from the outside can be interrupted more effectively. In addition, the solar heat acquisition rate is measured by using, for example, a spectrophotometer (U-4000 type, manufactured by Hitachi, Ltd.) in the same manner as described above, according to JIS R3106 (1998) “Transmissivity / reflectance / irradiation of plate glass”. It can be determined according to “Test method for heat gain”.

(Crow base material)
A commercially available glass material can be used as a glass substrate applied to the laminated glass according to the present invention.

  Although the kind of glass is not specifically limited, Usually, soda-lime silica glass is used suitably. In this case, it may be a colorless transparent glass or a colored transparent glass.

  Moreover, it is preferable that the glass substrate of the outdoor side close | similar to incident light among two glass base materials is a colorless transparent glass. Moreover, it is preferable that the glass substrate of the indoor side far from the incident light side is a green-colored colored transparent glass or dark colored transparent glass. The green colored transparent glass preferably has ultraviolet absorption performance and infrared absorption performance. By using these, the solar radiation energy can be reflected as much as possible on the outdoor side, and the solar radiation transmittance of the laminated glass can be further reduced.

Although the green colored transparent glass is not particularly limited, for example, soda lime silica glass containing iron is preferable. For example, it is soda-lime silica glass containing 0.3 to 1% by mass of total iron in terms of Fe ₂ O _{3 in} a soda-lime silica-based mother glass. Furthermore, since the absorption of light in the near-infrared region is dominated by divalent iron out of the total iron, the mass of FeO (divalent iron) is all in terms of Fe ₂ O _3. It is preferable that it is 20-40 mass% of iron.

In order to impart ultraviolet absorption performance, a method of adding cerium or the like to a soda lime silica base glass can be mentioned. Specifically, it is preferable to use soda lime silica glass having the following composition substantially. SiO _2: 65 to 75 _{wt%, Al} 2 O 3: _{0.1~5 wt%, Na 2 O + K 2} O: 10~18 wt%, CaO: 5 to 15 wt%, MgO: 1 to 6 wt%, Fe ₂ O ₃ converted total iron: 0.3 to 1% by mass, CeO ₂ converted total cerium or TiO ₂ : preferably in the range of 0.5 to 2% by mass Although it does not specifically limit, For example, the soda-lime silica glass which contains iron in high concentration is mentioned suitably.

  When using the laminated glass which concerns on this invention for windows, such as a vehicle, it is preferable that both the thickness of an indoor side glass base material and an outdoor side glass base material is 1.5-3.0 mm. In this case, the indoor side glass base material and the outdoor side glass base material can have the same thickness or different thicknesses. In using laminated glass for an automobile window, for example, both the indoor side glass base material and the outdoor side glass base material may have a thickness of 2.0 mm or a thickness of 2.1 mm. Moreover, when using laminated glass for an automobile window, for example, the total thickness of the laminated glass is reduced by setting the thickness of the indoor glass substrate to less than 2 mm and the thickness of the outdoor glass plate to 2 mm or more. In addition, it can resist external force from the outside of the vehicle. The indoor glass substrate and the outdoor glass substrate may be flat or curved. Since vehicles, particularly automobile windows, are often curved, the shape of the indoor side glass substrate and the outdoor side glass substrate is often curved. In this case, the infrared reflecting layer group is provided on the concave surface side of the outdoor glass substrate. Furthermore, if necessary, three or more glass substrates can be used.

  Although the manufacturing method of the laminated glass of this invention is not restrict | limited in particular, For example, the infrared reflective film which bonded the polyvinyl acetal type resin film to both surfaces of the infrared reflective layer unit which concerns on this invention, respectively is pinched | interposed with two glass base materials Then, after removing the excess part which protruded from the edge part of the glass base material as needed, the method of heating at 100-150 degreeC for 10 to 60 minutes, performing a pressure deaeration process, and performing a combined process is mentioned. It is done.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless there is particular notice, it represents "mass part" or "mass%", respectively.

<Production of infrared reflective film>
[Preparation of Infrared Reflecting Film 1]
[Preparation of coating solution for forming infrared reflective layer]
(Preparation of coating liquid L1 for forming a low refractive index layer)
680 parts of an aqueous solution containing colloidal silica (silicon dioxide, manufactured by Nissan Chemical Industries, Ltd., Snowtex (registered trademark) OXS, average particle size: 4 nm) at a concentration of 10% by mass as the second metal oxide particles; 30 parts by weight of 4.0% by weight polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-103: polymerization degree 300, saponification degree 98.5 mol%) and 150 parts by weight of 3.0% by weight boric acid aqueous solution were mixed. Distributed. After the dispersion, pure water was added to prepare 1000 parts of colloidal silica dispersion L1 as a whole.

  Next, the obtained colloidal silica dispersion L1 was heated to 45 ° C., and 4.0% by mass of the second water-soluble binder resin was polyvinyl alcohol (manufactured by Nihon Acetate / Poval Corporation, JP-45: 760 parts of an aqueous solution were added while stirring with a polymerization degree of 4500 and a saponification degree of 86.5-89.5 mol%. Thereafter, 40 parts of a 1% by weight betaine surfactant (manufactured by Kawaken Fine Chemical Co., Ltd., Sofazoline (registered trademark) LSB-R) aqueous solution was added to prepare a coating solution L1 for forming a low refractive index layer.

(Preparation of coating liquid L2 for forming a low refractive index layer)
In the preparation of the coating liquid L1 for forming the low refractive index layer, the infrared reflective layer group was similarly prepared except that the solid content of silicon dioxide (colloidal silica) as the second metal oxide particles was changed to 50% by mass. A coating solution L2 for forming a low refractive index layer used for forming the outermost layer was prepared.

(Preparation of coating liquid H1 for forming a high refractive index layer)
<Preparation of core / shell particles>
<Preparation of rutile titanium oxide constituting the core>
An aqueous suspension of titanium oxide was prepared such that the titanium oxide hydrate was suspended in water and the concentration when converted to TiO ₂ was 100 g / L. To 10 L aqueous suspension, 30 L sodium hydroxide aqueous solution (concentration 10 mol / L) was added with stirring, then heated to 90 ° C. and aged for 5 hours. Next, the solution was neutralized with hydrochloric acid, filtered, and washed with water.

  In the above reaction, the raw material titanium oxide hydrate is obtained by thermal hydrolysis of an aqueous titanium sulfate solution according to a known method.

The base-treated titanium compound was suspended in pure water so that the concentration when converted to TiO ₂ was 20 g / L. Therein, the 0.4 mol% of citric acid was added with stirring to TiO ₂ weight. After that, when the temperature of the mixed sol solution reaches 95 ° C., concentrated hydrochloric acid is added so that the hydrochloric acid concentration becomes 30 g / L. The mixture is stirred for 3 hours while maintaining the liquid temperature at 95 ° C. A liquid was prepared.

  When the pH and zeta potential of the titanium oxide sol solution obtained above were measured, the pH at 25 ° C. was 1.4 and the zeta potential was +40 mV. Moreover, when the particle size was measured with a Zetasizer Nano manufactured by Malvern, the monodispersity was 16%.

  Further, the titanium oxide sol solution was dried at 105 ° C. for 3 hours to obtain titanium oxide powder fine particles. The powder fine particles were subjected to X-ray diffraction measurement using JDX-3530 type manufactured by JEOL Datum Co., Ltd. and confirmed to be rutile type titanium oxide fine particles. The volume average particle diameter of the fine particles was 10 nm.

  Then, 4 kg of pure water containing 20.0% by mass of a titanium oxide sol aqueous dispersion containing rutile-type titanium oxide fine particles having a volume average particle size of 10 nm prepared above is added to 4 kg of pure water, and 10.0% by mass to become core particles. A titanium oxide sol aqueous dispersion was obtained.

<Preparation of core / shell particles by shell coating>
To 2 kg of pure water, 0.5 kg of 10.0 mass% titanium oxide sol aqueous dispersion as core particles was added and heated to 90 ° C. Next, 1.3 kg of an aqueous silicic acid solution prepared so that the concentration when converted to SiO ₂ is 2.0% by mass is gradually added, followed by heat treatment at 175 ° C. for 18 hours in an autoclave, and further concentrated. Thus, a core-shell particle (average particle size: 10 nm) sol solution (solid content concentration: 20% by mass) having core particles of titanium oxide having a rutile structure and SiO ₂ as a coating layer (shell part) was obtained. .

<Preparation of coating solution for forming a high refractive index layer>
28.9 parts of a sol solution containing core / shell particles as the first metal oxide particles having a solid content concentration of 20.0% by mass obtained above, and 10.5 parts of a 1.92% by mass citric acid aqueous solution. 10 parts by mass of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-103: polymerization degree 300, saponification degree 98.5 mol%) aqueous solution 2.0 parts, and 3% by mass boric acid aqueous solution 9.0 parts. By mixing, a core-shell particle dispersion H1 was prepared.

  Next, while stirring the core-shell particle dispersion H1 prepared above, 16.3 parts of pure water and 5.0% by weight of polyvinyl alcohol as a first water-soluble binder (manufactured by Kuraray Co., Ltd., PVA-124: polymerization) Degree 2400, saponification degree 98-99 mol%) 33.5 parts of aqueous solution was added. Furthermore, 0.5 part of a 1% by weight betaine surfactant (manufactured by Kawaken Fine Chemical Co., Ltd., sofazoline (registered trademark) LSB-R) aqueous solution was added, and a high refractive index of 1000 parts as a whole using pure water. A layer forming coating solution H1 was prepared.

[Formation of infrared reflection layer unit 1]
Using the slide hopper coating apparatus capable of simultaneous multilayer coating, the above prepared low refractive index layer forming coating liquid L1, low refractive index layer forming coating liquid L2 and high refractive index layer forming coating liquid H1 are kept at 45 ° C. On the other side of the transparent substrate (2), a polyethylene terephthalate film having a thickness of 50 μm heated to 45 ° C. (Cosmo Shine A4300, double-sided adhesive bonding treatment, abbreviated as PET film) manufactured by Toyobo Co., Ltd. The high refractive index layer H1 and the low refractive index layers L1 and L2 were applied so that the film thickness at the time of drying was 130 nm to form an infrared reflective layer group (ML).

Specifically, one surface of the PET film (2) is a low refractive index layer L1 (T ₁ ), and a high refractive index layer H1 (T ₂ ) is laminated thereon, and in this configuration, eight layers are alternately arranged. A total of 16 layers are laminated one by one, and a low refractive index layer L2 (T _n ) having a silicon dioxide content of 50% by mass is formed on the 16th high refractive index layer H1, and 17 simultaneous multilayers are formed. Application was performed.

  Immediately after application, 5 ° C. cold air was blown and set. At this time, even if the surface was touched with a finger, the time until the finger was lost (set time) was 5 minutes.

  After completion of the setting, warm air of 80 ° C. was blown and dried to prepare an infrared reflection layer unit (U) 1 having 17 layers of infrared reflection layers (ML) on one side of the PET film.

  In addition, the code | symbol displayed in the parenthesis after each component represents the code | symbol described in FIG.

[Production of infrared reflective film: bonding of polyvinyl acetal resin film]
A polyvinyl butyral film having a thickness of 380 μm is applied as a polyvinyl acetal resin film to both surfaces (on the low refractive index layer L2 and the back surface side of the PET film) of the infrared reflection layer unit (U) 1 produced as described above. The nip rollers were bonded under the conditions of a bonding pressure of 10 MPa and a bonding temperature of 10 ° C. to produce an infrared reflective film 1 having the configuration shown in FIG.

[Preparation of infrared reflective film 2]
In the production of the infrared reflective film 1, the polyvinyl acetal resin film provided on both surfaces of the infrared reflective layer unit (U) 1 is used as an ATO powder (ultrafine particle Sb-doped SnO (ATO), An infrared reflective film 2 was produced in the same manner except that the polyvinyl butyral film containing 50% by mass of Sumitomo Metal Mining Co., Ltd. was used.

[Preparation of Infrared Reflective Films 3 to 10]
In the production of the infrared reflective film 2, the film thickness of the transparent substrate, the silicon dioxide content of the low refractive index layer L2, which is the outermost layer, the presence or absence of the IR absorber in the polyvinyl butyral film, and the bonding conditions (bonding pressure) Infrared reflective films 3 to 10 were produced in the same manner except that the contents described in Table 1 were changed.

[Preparation of Infrared Reflecting Film 11: Forming Infrared Reflecting Layers on Both Sides of Transparent Base Material]
In the production of the infrared reflective film 1, two infrared reflective layer groups (MLa, MLb, each having 17 layers) having the same configuration as the infrared reflective layer group (ML) are formed on both surfaces of the PET film which is a transparent substrate. Then, the content of silicon dioxide in each outermost layer (Tan, Tbn) was changed to 54% by mass to obtain the configuration shown in FIG. 2, except that the bonding pressure at the time of bonding the polyvinyl butyral film was changed to 50 MPa. Similarly, the infrared reflective film 11 was produced.

[Preparation of Infrared Reflective Film 12]
In the production of the infrared reflective film 11, the polyvinyl acetal resin films (3A and 3B) applied to both surfaces of the infrared reflective layer unit 1 are used as ATO powder (ultrafine particle Sb-doped SnO (ATO) as an IR absorber (infrared absorber). ), Manufactured by Sumitomo Metal Mining Co., Ltd.), an infrared reflective film 12 was produced in the same manner except that the polyvinyl butyral film containing 50% by mass was changed.

[Production of Infrared Reflective Films 13 and 14]
In preparation of the said infrared reflective film 12, except having changed the content rate of IR absorber in a polyvinyl butyral film | membrane (3A and 3B) to 30 mass% and 80 mass%, respectively, infrared reflective film 13 and 14 was carried out. Produced.

[Preparation of Infrared Reflective Films 15-17]
In the production of the infrared reflective film 9, the infrared reflective film 15 was similarly prepared except that the total number of layers of the infrared reflective layer group (ML) and the content of silicon dioxide in the outermost layer were changed to the conditions shown in Table 1. ~ 17 were made.

[Preparation of Infrared Reflecting Film 18]
In the production of the infrared reflective film 12, the infrared reflective film was similarly formed except that the total number of layers of the infrared reflective layer group (MLa, MLb) and the content of silicon dioxide in the outermost layer were changed to the conditions shown in Table 1. The infrared reflective film 18 which has a layer group on both surfaces of a transparent base material was produced.

[Production of Infrared Reflective Films 19 and 20]
In the production of the infrared reflective film 12, the transparent base materials were triacetyl cellulose films (trade name: Konica Minolta TAC KC6UA, thickness: 60 μm, manufactured by Konica Minolta Co., Ltd.), cycloolefin polymer films (trade name: Zeonea (registered) Infrared reflective films 19 and 20 were produced in the same manner except that the thickness was changed to (trademark), thickness: 60 μm, manufactured by Zeon Corporation.

[Preparation of Infrared Reflecting Film 21]
Infrared reflective film 21 was produced according to the method described in Example 1 of JP-A-60-225747.

  As a transparent substrate, a biaxially stretched PET film with a thickness of 100 μm is used. On one surface side, a first layer is a titanium film with a thickness of 1.0 nm by DC magnetron sputtering, and a second layer is DC magnetron sputtering. Thus, a silver-copper alloy layer having a thickness of 12.0 nm, a titanium film having a thickness of 2.0 nm by DC magnetron sputtering as a third layer, and a titanium oxide film having a thickness of 20 μm by a wet coating method were formed as a fourth layer. In addition, a 20 μm titanium oxide film was provided on the back side of the PET film by a wet coating method to produce an infrared reflective layer unit.

  Next, a polyvinyl butyral sheet having a thickness of 380 μm was bonded to both surfaces of the infrared reflective layer unit to produce an infrared reflective film 21.

[Preparation of Infrared Reflective Film 22]
In the production of the infrared reflective film 7, an infrared reflective film 22 was produced in the same manner except that only the infrared reflective layer unit was used and the polyvinyl butyral layer was removed.

  The details of the infrared reflective films 1 to 22 produced as described above are shown in Table 1.

  Details of the components described in Table 1 with abbreviations and the like are as follows.

PET: Polyethylene terephthalate TAC: Triacetyl cellulose COP: Cycloolefin polymer PVA: Polyvinyl alcohol PVB: Polyvinyl butyral << Preparation of laminated glass >>
[Preparation of laminated glass 1A]
As the indoor side glass, a planar green glass having a thickness of 3 mm (visible light transmittance Tv: 81%, solar transmittance Te: 63%), the infrared reflection film 1 produced as described above, and the outdoor side glass having a thickness of 3 mm Flat clear glass (visible light transmittance Tv: 91%, solar radiation transmittance Te: 86%) is laminated in this order, and after removing the excess portion protruding from the edge portion of the glass, it is heated at 135 ° C. for 30 minutes. Then, the laminated glass 1A was produced by performing degassing under pressure and performing a lamination process.

[Production of Laminated Glass 2A-21A]
In the production of the laminated glass 1A, laminated glasses 2A to 21A were produced in the same manner except that the produced infrared reflective films 2A to 21A were used instead of the infrared reflective film 1A.

[Production of laminated glass 22A]
As the indoor glass, a polyvinyl butyral film having a thickness of 380 μm is formed on the adhesive surface of the planar green glass having a thickness of 3 mm (visible light transmittance Tv: 81%, solar transmittance Te: 63%) and the infrared reflective film 22. Pasted. Pasted. Further, a polyvinyl butyral film having a thickness of 380 μm is adhered to the infrared reflective film 22 of a flat clear glass having a thickness of 3 mm (visible light transmittance Tv: 91%, solar transmittance Te: 86%) as the outdoor glass. Was pasted.

  Next, a planar indoor glass having a polyvinyl butyral film, an infrared reflective film 22, and a planar outdoor glass having a polyvinyl butyral film are laminated in a configuration in which the infrared reflective film 22 is sandwiched between the polyvinyl butyral films, After removing the excess part which protruded from the edge part of glass, it heated at 135 degreeC for 30 minute (s), pressure deaerated, and the lamination process was performed, and laminated glass 22A was produced.

[Production of Laminated Glasses 1B-22B]
In the production of the laminated glasses 1A to 22A, laminated glasses 1B to 22B were produced in the same manner except that a glass having a curved shape for vehicles was used instead of the green glass on the plane.

<Evaluation of laminated glass>
About each produced said laminated glass, the following characteristic value measurement and performance evaluation were performed.

[Evaluation of laminated glass immediately after production]
(Measurement of solar heat gain rate (T _TS ))
Using a spectrophotometer (using an integrating sphere, manufactured by Hitachi, Ltd., U-4000 type), transmittance and reflectance were measured every 5 nm in a 300 to 2500 nm region of laminated glass 1A to 22A. Next, according to the method described in JIS R3106 (1998), calculation processing of each measured value of excess rate and reflectance and the solar reflection weight coefficient was performed to obtain the solar heat acquisition rate (T _TS ).

(Evaluation of electromagnetic wave transmission)
A rectangular parallelepiped having a width of 50 cm, a length of 50 cm, and a height of 30 nm was prepared, and a laminated glass 1A to 22A having a width of 50 cm and a length of 50 cm was used as an upper lid material, and a liquid crystal television was set therein. Next, an image was displayed on the liquid crystal television, the display state of the image was visually observed, and electromagnetic wave permeability was evaluated according to the following criteria.

○: The electromagnetic wave is not shielded and the image is not disturbed. Δ: The image is slightly disturbed, but the quality is practically acceptable. ×: The image is greatly disturbed or the image disappears without passing through the radio wave. (Evaluation of curved surface tracking)
About laminated glass 1B-22B produced using curved glass, visual observation and loupe observation were performed about the film surface state of an infrared reflective film, and curved surface followability was evaluated according to the following standard.

◎: Even when sandwiched between curved glass, no change is observed in the film surface state of the infrared reflecting film. ○: When sandwiched between curved glass, fine wrinkles are generated at the edge of the infrared reflecting film, but good film. △: When sandwiched between curved glass, wrinkles are generated in a region where the curved portion of the infrared reflecting film is strong, but it is a quality acceptable for practical use. ×: When sandwiched between curved glass, the entire surface of the infrared reflecting film Wrinkles and cracks occur in the infrared reflective layer, and the quality is unacceptable for practical use (measurement of film breaking elongation)
About the produced infrared reflective films 1-22, the film breaking elongation (%) was measured in accordance with the following method.

  Using an adjustable temperature tensile tester (Shimadzu Autograph AGS-100D, manufactured by Shimadzu Corporation), an infrared reflective film cut to a width of 10 mm was pulled at 23 ° C., a distance between chucks of 50 mm, and a tensile speed of 300 mm / min. The elongation rate (%) until rupture was determined, and this was defined as the film elongation at break (%).

(Evaluation of uneven color tolerance)
About the produced laminated glass 1A-22A, the presence or absence of generation | occurrence | production of a color nonuniformity was observed visually, and color nonuniformity tolerance was evaluated according to the following reference | standard.

◎: No color unevenness is observed at all ○: Very slight color unevenness is generated, but it is almost good characteristics △: Although slight color unevenness is observed, it is a quality acceptable for practical use. Yes ×: Quality that causes strong color unevenness and is a problem in practical use. ××: Peripheral reflections are poor, transparency is low, and the quality is unacceptable for practical use. Evaluation: Evaluation of durability)
Each of the prepared infrared reflective films and each laminated glass was stored for 3 months in an environment of 40 ° C. and 80% RH, and then measured for solar heat gain (T _TS ) and electromagnetic waves in the same manner as described above. Evaluation of permeability, evaluation of curved surface followability, measurement of film elongation at break, and evaluation of color unevenness resistance were performed.

  The results obtained as described above are shown in Table 2.

  As is clear from the results shown in Table 2, the infrared reflective film of the present invention and the laminated glass produced using the same have excellent solar heat gain, electromagnetic wave permeability, and film break elongation relative to the comparative example. It can be seen that it has excellent characteristics of curved surface followability and color unevenness resistance.

  Furthermore, it can be seen that the infrared reflective film of the present invention and the laminated glass produced using the same maintain the above-described excellent characteristics even after being stored for a long period of time in a high-temperature and high-humidity environment.

  The infrared reflective film of the present invention has characteristics excellent in solar heat acquisition rate, electromagnetic wave permeability, film breakage resistance, curved surface followability and color unevenness resistance, and as a laminated glass equipped with the same, a windshield of a vehicle body or a building It can be suitably used for windows.

1 infrared reflective film 2 transparent substrate 3A, 3B polyvinyl acetal resin film ML, MLa, MLb infrared reflecting layer group _{T 1 ~T n, Ta 1 ~Ta} n, Tb 1 ~Tb n infrared reflecting layer U infrared reflective layer unit

Claims (12)

An infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles,
An infrared reflective film comprising a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit.   The infrared reflective film according to claim 1, wherein the polyvinyl acetal resin film is a polyvinyl butyral film.   The infrared reflective layer in contact with the polyvinyl acetal resin film constituting the infrared reflective layer unit contains silicon dioxide in the range of 10 to 60 mass% as the metal oxide particles. The infrared reflective film according to claim 2.   The infrared reflective layer unit has a high refractive index infrared reflective layer containing a first water-soluble binder resin and first metal oxide particles on at least one surface side on a transparent substrate, and a second water-soluble layer. 4. A structure having an infrared reflection layer group in which a low-refractive-index infrared reflection layer containing a conductive binder resin and a second metal oxide particle is alternately laminated. The infrared reflective film as described in any one of.   The infrared reflection film according to claim 4, wherein the infrared reflection layer unit has the alternately laminated infrared reflection layer group on both surfaces of the transparent substrate. A method for producing an infrared reflective film having an infrared reflective layer unit containing at least a water-soluble binder resin and metal oxide particles,
A method for producing an infrared reflective film, comprising producing a polyvinyl acetal resin film on both surfaces of the infrared reflective layer unit.   The method for producing an infrared reflecting film according to claim 6, wherein the polyvinyl acetal resin film is a polyvinyl butyral film.   The infrared reflective film according to claim 6 or 7, wherein a polyvinyl acetal resin film is bonded to both surfaces of the infrared reflective layer unit at a pressure within a range of 1 to 50 MPa. Production method.   The infrared reflective layer in contact with the polyvinyl acetal resin film constituting the infrared reflective layer unit is formed by containing silicon dioxide in the range of 10 to 60 mass% as the metal oxide particles. The manufacturing method of the infrared reflective film as described in any one of Claim 6- Claim 8.   The infrared reflective layer unit has a high refractive index infrared reflective layer containing a first water-soluble binder resin and first metal oxide particles on at least one surface side on a transparent substrate, and a second water-soluble layer. 10. An infrared reflecting layer group in which an adhesive binder resin and an infrared reflecting layer having a low refractive index containing second metal oxide particles are alternately laminated to form an infrared reflecting layer group. The manufacturing method of the infrared reflective film as described in any one of the above.   The method for producing an infrared reflective film according to claim 10, wherein the infrared reflective layer unit is formed by forming the alternately laminated infrared reflective layer group on both surfaces of the transparent substrate.   A method for producing a laminated glass, comprising producing the infrared reflective film according to any one of claims 1 to 5 by sandwiching it between two glass substrates.

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