WO2014073379A1

WO2014073379A1 - Optical multilayer film, infrared shielding film, and infrared shielding body

Info

Publication number: WO2014073379A1
Application number: PCT/JP2013/078732
Authority: WO
Inventors: 友香子高
Original assignee: コニカミノルタ株式会社
Priority date: 2012-11-08
Filing date: 2013-10-23
Publication date: 2014-05-15
Also published as: JPWO2014073379A1; JP6225916B2

Abstract

The purpose of the present invention is to provide: an optical multilayer film which has excellent interlayer adhesion; an infrared shielding film; and an infrared shielding body which is provided with the infrared shielding film. An optical multilayer film of the present invention comprises a base and a reflective layer that reflects at least light. The reflective layer has a plurality of laminated refractive index layers, and at least one refractive index layer has a refractive index that is different from that of at least one of the refractive index layers adjacent to the one refractive index layer. The refractive index layers contain a polyvinyl alcohol resin. The average polymerization degree of the polyvinyl alcohol resin contained in one refractive index layer is different from the average polymerization degree of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer; or alternatively, the polymerization degree of the maximum amount of the polyvinyl alcohol resin contained in one refractive index layer is different from the polymerization degree of the maximum amount of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer.

Description

Optical laminated film, infrared shielding film and infrared shielding body

The present invention relates to an optical laminated film, an infrared shielding film, and an infrared shielding body.

In recent years, due to increased interest in energy conservation, there has been an increasing demand for infrared shielding films that can be attached to window glass of buildings and vehicles to block the transmission of solar heat rays in order to reduce the load on cooling equipment. Yes.

Conventionally, as an infrared shielding film, it has been proposed to produce a laminated film in which a high refractive index layer and a low refractive index layer are alternately laminated by a dry film forming method such as vapor deposition or sputtering. It is also known that the optical film thickness of the laminated film laminated alternately can be adjusted so as to reflect visible light instead of infrared light.

However, the dry film forming method has problems such as a large vacuum apparatus used for forming, high manufacturing cost, difficulty in increasing the area, and further, the base material is limited to a heat-resistant material.

Recently, a method for forming a near-infrared reflective film using a wet coating method instead of the dry film forming method having the above-described problems has been reported (for example, see Patent Document 1).

International Publication No. 2012/014607 (equivalent to US 2013/0107355 A1)

However, the near-infrared reflective film disclosed in Patent Document 1 has a problem that interlayer adhesion is not sufficient.

Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide an optical laminated film having good interlayer adhesion, an infrared shielding film, and an infrared shielding body provided with the infrared shielding film. And

The present inventor has intensively studied in view of the above problems. As a result, it has been found that the interlayer adhesion of each refractive index layer is improved by changing the polymerization degree of the polyvinyl alcohol resin contained in the adjacent refractive index layer, and the present invention has been completed.

That is, in order to realize at least one of the above objects, an optical laminated film reflecting one aspect of the present invention is an optical laminated film having a base material and at least a reflective layer that reflects light, The reflective layer has a plurality of laminated refractive index layers, at least one of the refractive index layers has a refractive index different from at least one of the adjacent refractive index layers, and the refractive index layer is polyvinyl alcohol. The average polymerization degree of the polyvinyl alcohol resin contained in one refractive index layer is different from the average polymerization degree of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer, Alternatively, the degree of polymerization of the maximum amount of the polyvinyl alcohol-based resin contained in one refractive index layer is the maximum amount of the polymer contained in at least one of the refractive index layers adjacent to the refractive index layer. Different from the degree of polymerization of the vinyl alcohol-based resin.

The above object of the present invention is also an infrared shielding film having a base material and a reflective layer that reflects at least infrared light, the reflective layer having a plurality of laminated refractive index layers, At least one of the refractive index layers has a refractive index different from that of at least one of the adjacent refractive index layers, and the refractive index layer contains a polyvinyl alcohol-based resin, and is included in one refractive index layer. The average degree of polymerization of the resin is different from the average degree of polymerization of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer, or the maximum amount of polyvinyl alcohol resin contained in one of the refractive index layers. Is achieved by an infrared shielding film having a degree of polymerization different from that of the maximum amount of polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer. .

The present invention is an optical laminated film having a base material and at least a reflective layer that reflects light, wherein the reflective layer has a plurality of laminated refractive index layers, and at least one of the refractive index layers. One has a refractive index different from at least one of the adjacent refractive index layers, the refractive index layer contains a polyvinyl alcohol resin, and the average degree of polymerization of the polyvinyl alcohol resin contained in one refractive index layer is The average degree of polymerization of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer, or the degree of polymerization of the maximum amount of polyvinyl alcohol resin contained in one refractive index layer is the refractive index. Provided is an optical laminated film having a polymerization degree different from that of the maximum amount of the polyvinyl alcohol-based resin contained in at least one of the refractive index layers adjacent to the layer.

The present invention is characterized in that the average polymerization degree of the polyvinyl alcohol resin contained in the two adjacent refractive index layers or the polymerization degree of the maximum amount of polyvinyl alcohol resin is different. The optical laminated film having such a configuration is excellent in interlayer adhesion. Here, the mechanism for exerting the above-described effects by the configuration of the present invention is presumed as follows. The present invention is not limited to the following. That is, in the refractive index layer containing the metal oxide fine particles and the polyvinyl alcohol-based resin, the hydroxyl groups of the polyvinyl alcohol-based resin and the hydroxyl groups of the metal oxide fine particles (for example, —OH included in the silicon dioxide particles) are loosened by hydrogen bonding. Form a network. Therefore, the reactivity of the metal oxide particles (for example, —OH reactivity of the silicon dioxide particles) is suppressed, and the interaction between the metal oxide particles and the metal oxide particles contained in the adjacent refractive index layer. Is inhibited. As a result, it becomes difficult for the metal oxide particles contained in the adjacent refractive index layers to be mixed (mixing between refractive index layers (interlayer mixing) is suppressed), and light reflectance, particularly infrared reflectance (infrared shielding ratio). ) Can be improved. For this reason, when light reflectivity (especially infrared shielding) is considered, it is preferable that the polymerization degree of the polyvinyl alcohol-type resin in a refractive index layer is large. On the other hand, a refractive index layer containing a polyvinyl alcohol-based resin having a high degree of polymerization forms a strong network and thus becomes hard. Therefore, when a refractive index layer containing a polyvinyl alcohol resin having the same degree of polymerization is laminated, a hard film having the same strength is laminated, resulting in poor interlayer adhesion. Therefore, by interposing a film having a lower polymerization degree between films having a higher degree of polymerization, interlayer mixing can be suppressed (light reflectivity, particularly infrared shielding properties can be ensured) and interlayer adhesion can be improved. . Therefore, according to the present invention, an optical laminated film having excellent interlayer adhesion, an infrared shielding film, and an infrared shielding body provided with the infrared shielding film can be provided.

In particular, the above effect (interlayer adhesion) can be further improved by setting the average polymerization degree difference or the polymerization degree difference of polyvinyl alcohol resins in adjacent refractive index layers to 300 or more. Moreover, light reflectivity, especially infrared shielding property can be improved more by providing the said polymerization degree difference. Specifically, a layer containing a polyvinyl alcohol resin having a high degree of polymerization (hereinafter also referred to as “first polyvinyl alcohol resin”) (hereinafter also referred to as “high degree of polymerization resin layer”) has a higher degree of polymerization. Compared with a layer containing a polyvinyl alcohol resin having a low degree of polymerization (hereinafter also referred to as “second polyvinyl alcohol resin”) (hereinafter also referred to as “low polymerization degree resin layer”), ) Form a network structure. Therefore, the high polymerization degree resin layer A becomes difficult to mix with other adjacent layers (hereinafter referred to as “adjacent layers”). On the other hand, when the high polymerization degree resin layer B in which the adjacent layer also forms a strong network structure, at the interface between the high polymerization degree resin layer A and the high polymerization degree resin layer B (adjacent layer of the high polymerization degree resin layer A). Disturbance (unevenness) may occur, and as a result, the infrared reflectance may be lowered. However, the degree of polymerization of the second polyvinyl alcohol-based resin contained in the adjacent layer of the layer containing the first polyvinyl alcohol-based resin has a polymerization degree difference of 300 or more from the degree of polymerization of the first polyvinyl alcohol-based resin. Thereby, disorder (unevenness | corrugation) of an interface is suppressed and a light reflectance, especially infrared reflectance (infrared shielding factor) can be made higher. In particular, by making the polymerization degree of the polyvinyl alcohol resin contained in the low refractive index layer 300 or more higher than the polymerization degree of the polyvinyl alcohol resin contained in the high refractive index layer, the above effects (interlayer adhesion, light reflectance, particularly (Infrared shielding) can be exhibited more.

In particular, by increasing the thickness of the refractive index layer (lowermost layer) located closest to the base material of the reflective layer, the adhesion with the base material can be further improved, and better coating properties can be achieved.

In addition, particularly when the refractive index layer contains a modified polyvinyl alcohol, it is possible to more effectively suppress fluctuations in haze during storage under high humidity conditions.

Furthermore, the refractive index layer includes a high refractive index layer containing titanium oxide as metal oxide particles, and a low refractive index layer, and the high refractive index layer does not contain gelatin and thickening polysaccharides. Haze fluctuations during storage under high humidity conditions can be more effectively suppressed.

As described above, the optical laminated film of the present invention has excellent interlayer adhesion, high visible light transmittance, and excellent infrared shielding properties. Furthermore, the infrared shielding film of the present invention can be manufactured using a water-based coating solution for refractive index, and can be manufactured in a large area at a low cost.

Hereinafter, the components of the optical laminated film of the present invention, the form for carrying out the present invention, and the like will be described in detail.

In the present specification, “X to Y” indicating a range means “X or more and Y or less”, “weight” and “mass”, “weight%” and “mass%”, “part by weight” and “weight part”. “Part by mass” is treated as a synonym. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%.

[Optical laminated film]
The optical laminated film of this embodiment includes a base material and a reflective layer that reflects at least infrared light. Here, the reflective layer has a plurality of stacked refractive index layers, and at least one of the refractive index layers has a refractive index different from at least one of the adjacent refractive index layers, preferably adjacent refractive index layers. Refractive index different from both. In general, the refractive index layer includes at least one laminate (unit) composed of a low refractive index layer and a high refractive index layer, and the low refractive index layer and the high refractive index layer are alternately laminated. It is preferable to have the form of an alternating laminate. In the present specification, a refractive index layer having a higher refractive index than the other is referred to as a high refractive index layer, and a refractive index layer having a lower refractive index than the other is referred to as a low refractive index layer. In this specification, the terms “high refractive index layer” and “low refractive index layer” refer to a refractive index layer having a higher refractive index when comparing the refractive index difference between two adjacent layers. It means that the lower refractive index layer is a low refractive index layer. Therefore, the terms “high refractive index layer” and “low refractive index layer” are the same when each refractive index layer constituting the optical laminated film is focused on two adjacent refractive index layers. All forms other than those having a refractive index are included. The optical laminated film has a reflective layer that reflects light including ultraviolet light and infrared light, and is preferably an infrared shielding film having a reflective layer that mainly reflects at least infrared light. That is, according to a preferred embodiment of the present invention, the infrared shielding film has a base material and at least a reflective layer that reflects light, and the reflective layer has a plurality of laminated refractive index layers, At least one of the refractive index layers has a refractive index different from that of at least one of the adjacent refractive index layers, and the refractive index layer contains a polyvinyl alcohol-based resin, and is included in one refractive index layer. The average degree of polymerization of the resin is different from the average degree of polymerization of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer, or the maximum amount of polyvinyl alcohol resin contained in one of the refractive index layers. An infrared shielding film having a polymerization degree different from that of the maximum amount of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer. It is. For this reason, below, these may be called an "optical laminated | multilayer film" or an "infrared shielding film."

In the present invention, the optical laminated film includes at least one unit composed of two layers having different refractive indexes, that is, a high refractive index layer and a low refractive index layer. The rate layer is considered as follows. For example, when each of the high refractive index layer and the low refractive index layer contains metal oxide particles, metal oxide particles contained in the low refractive index layer (hereinafter, also referred to as “first metal oxide particles”), Metal oxide particles (hereinafter also referred to as “second metal oxide particles”) contained in the high refractive index layer are mixed at the interface between the two layers, and the first metal oxide particles and the second metal are mixed. A layer containing oxide particles may be formed. In that case, it is regarded as a low refractive index layer or a high refractive index layer depending on the abundance ratio of the first metal oxide particles and the second metal oxide particles. Specifically, the low refractive index layer means that the first metal oxide particles are 50 to 100% by mass with respect to the total mass of the first metal oxide particles and the second metal oxide particles. Means the layers involved. The high refractive index layer means that the second metal oxide particles are more than 50% by mass and less than 100% by mass with respect to the total mass of the first metal oxide particles and the second metal oxide particles. Means the layers involved. The type and amount of metal oxide particles contained in the refractive index layer can be analyzed by energy dispersive X-ray spectroscopy (EDX). Alternatively, the metal oxide concentration profile in the film thickness direction of the laminated film can be measured, and can be regarded as a high refractive index layer or a low refractive index layer depending on the composition. The metal oxide concentration profile of the laminated film is sputtered from the surface in the depth direction using a sputtering method, and is sputtered at a rate of 0.5 nm / min using the XPS surface analyzer with the outermost surface being 0 nm. It can be observed by measuring the atomic composition ratio. Similarly, in a laminate in which metal oxide particles are not contained in a low refractive index component or a high refractive index component and formed only from an organic binder, an organic binder concentration profile is used, for example, a film. By measuring the carbon concentration in the thickness direction, it is confirmed that the mixed region exists, and further, the composition is measured by EDX, so that each layer etched by sputtering is either a high refractive index layer or a low refractive index layer. Can be considered a layer. The XPS surface analyzer is not particularly limited, and any model can be used. However, in this specification, ESCALAB-200R manufactured by VG Scientific Fix Co. was 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).

Generally, in an infrared shielding film, it is preferable to design a large difference in refractive index between a low refractive index layer and a high refractive index layer from the viewpoint that the infrared reflectance can be increased with a small number of layers. In this embodiment, in at least one of the laminates (units) composed of the low refractive index layer and the high refractive index layer, the difference in refractive index between the adjacent low refractive index layer and high refractive index layer is 0.1 or more. Preferably, it is 0.3 or more, more preferably 0.35 or more, and particularly preferably 0.4 or more. When the infrared shielding film has a plurality of laminates (units) of a high refractive index layer and a low refractive index layer, the refractive index difference between the high refractive index layer and the low refractive index layer in all the laminates (units) is It is preferable that it exists in the said suitable range. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used. In the infrared shielding film of this embodiment, the preferred refractive index of the low refractive index layer is 1.10 to 1.60, more preferably 1.30 to 1.50. The preferable refractive index of the high refractive index layer is 1.80 to 2.50, more preferably 1.90 to 2.20.

The reflectance in a specific wavelength region is determined by the difference in refractive index between two adjacent layers and the number of layers, and the larger the difference in refractive index, the same reflectance can be obtained with a smaller number of layers. 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 an 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.

Furthermore, as an optical characteristic of the optical laminated film of this embodiment (infrared shielding film; hereinafter the same), the transmittance in the visible light region shown in JIS R3106-1998 is 50% or more, preferably 75% or more, more preferably. Is preferably 85% or more, and it is preferable that the region having a wavelength of 900 nm to 1400 nm has a region with a reflectance exceeding 50%.

The infrared shielding film of the present embodiment may have any structure including at least one laminate (unit) composed of a high refractive index layer and a low refractive index layer on a base material. As the number of layers of the high refractive index layer and the low refractive index layer, from the above viewpoint, the range of the total number of layers is 100 layers or less, that is, 50 units or less, more preferably 40 layers (20 units) or less. More preferably, it is 30 layers (15 units) or less. In addition, the infrared shielding film of the present invention may have a configuration in which at least one of the above units is laminated, for example, a laminated film in which both the outermost layer and the lowermost layer of the laminated film are a high refractive index layer or a low refractive index layer. Although it may be a film, it is preferable that the low refractive index layer is located closest to the substrate side of the reflective layer from the viewpoint of adhesion to the substrate. As the infrared shielding film of the present invention, a layer structure in which the lowermost layer located on the most substrate side (preferably adjacent to the substrate) is a low refractive index layer and the outermost layer is also a low refractive index layer is more preferable. .

The total thickness of the infrared shielding film of this embodiment is preferably 12 μm to 315 μm, more preferably 15 μm to 200 μm, and still more preferably 20 μm to 100 μm. Further, the thickness per one layer of the low refractive index layers other than the layer located closest to the substrate is preferably 20 to 800 nm, and more preferably 50 to 350 nm. On the other hand, the thickness per layer of the high refractive index layer other than the layer located closest to the substrate is preferably 20 to 800 nm, and more preferably 50 nm to 350 nm.

In the infrared shielding film of this embodiment, at least one of the plurality of high refractive index layers is different in thickness from the other layers (all the high refractive index layers are not the same thickness) or a plurality of low refractive indexes. It is preferable that at least one of the refractive index layers has a different thickness (not all low refractive index layers have the same thickness). With this configuration, it is possible to further improve the adhesion and coating properties with the substrate, and to easily widen or narrow the reflected wavelength range.

Here, among the refractive index layers constituting the reflective layer, the refractive index layer located closest to the base material side of the reflective layer (in this specification, simply referred to as “lowermost layer”) is a refractive index other than the lowermost layer. The film thickness is preferably 5 times or more thicker than the layer (other refractive index layers), more preferably 9 times or more thicker. Thus, by making the lowest layer thick, adhesiveness with a base material can be improved and favorable applicability | paintability can be achieved. Here, the ratio of the thickness of the lowermost layer to the thickness (average thickness: total thickness / number of layers) of the other refractive index layers [= (thickness of the lowermost layer (nm)) / (of other refractive index layers (Thickness (nm))] is preferably 5 times or more, more preferably 9 times or more, still more preferably 10 to 20 times, and particularly preferably 10 to 13 times. . With this configuration, it is possible to further improve the adhesion to the substrate and the applicability. Moreover, generation | occurrence | production of a coating stripe etc. can be suppressed, while a lowermost layer has fixed intensity | strength. As a result, the problem of sticking the infrared shielding film to the substrate and the generation of cracks can be prevented, and the visible light transmittance and infrared shielding property of the infrared shielding film can be suppressed from decreasing. The “other refractive index layer” means all refractive index layers other than the lowest layer located on the side where the refractive index layer (lowermost layer) located closest to the substrate is provided. Therefore, when the refractive index layer is formed on the side opposite to the side on which the lowermost layer is provided (when the refractive index layer is formed on both surfaces of the base material), the opposite refractive index layer is “other refractive index. It is not included in the “layer”. Since the thickness (film thickness) of the lowermost layer is compared with the average thickness (average film thickness) of other refractive index layers constituting the reflective layer, some of the other refractive index layers are thicker than the lowermost layer. May contain layers. Further, the lowermost layer is located on the most substrate side of the reflective layer. For this reason, for example, when a functional layer as described in detail below is provided as an intermediate layer between the base material and the lowermost layer, the lowermost layer is in contact with the functional layer, not the base material, The adhesion between the lowermost layer and the functional layer can be improved.

In this embodiment, it is preferable that the lowermost layer contains an emulsion resin because the above effect can be achieved more effectively. Here, the emulsion resin is usually a resin formed by fusing a polymer dispersed in an aqueous solvent at the time of forming the lowermost layer in the manufacturing process of the infrared shielding film. An emulsion as a raw material for the emulsion resin is obtained by emulsion polymerization of an oil-soluble monomer using a polymer dispersant or the like.

Oil-soluble monomers that can be used are not particularly limited, but ethylene, propylene, butadiene, vinyl acetate and its partial hydrolyzate, vinyl ether, acrylic acid and its esters, methacrylic acid and its esters, acrylamide and its derivatives, Examples thereof include methacrylamide and derivatives thereof, styrene, divinylbenzene, vinyl chloride, vinylidene chloride, maleic acid, vinyl pyrrolidone and the like. Of these, acrylic acid, its esters, and vinyl acetate are preferably used from the viewpoint of transparency and particle size.

As acrylic acid and / or its esters and vinyl acetate emulsion, commercially available ones may be used. For example, Acryt UW-309, UW-319SX, UW-520 (manufactured by Taisei Fine Chemical Co., Ltd.), and Mobile vinyl (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and the like.

Further, the dispersant that can be used is not particularly limited, but in addition to a low-molecular dispersant such as alkyl sulfonate, alkyl benzene sulfonate, diethylamine, ethylenediamine, quaternary ammonium salt, polyoxyethylene nonylphenyl ether. , Polymer dispersing agents such as polyoxyethylene lauryl ether, hydroxyethyl cellulose, and polyvinylpyrrolidone. The emulsion described above preferably has a glass transition temperature (Tg) of 20 ° C. or lower, more preferably −30 to 10 ° C., from the viewpoint of enhancing flexibility.

The content of the emulsion resin in the lowermost layer is preferably 0.5 to 20% by mass, and more preferably 1 to 10% by mass with respect to the total mass of the lowermost layer. Further, regarding the relationship with the water-soluble resin contained in the lowermost layer, the water-soluble resin is preferably contained in a mass 1 to 10 times that of the emulsion. When the film forming step is obtained and dried, the structure of the water-soluble resin is maintained. Therefore, it is preferable that the water-soluble resin is contained in an amount equal to or greater than that of the emulsion resin because the film-forming property during production is excellent.

The infrared shielding film is a conductive layer, an antistatic layer, a gas barrier layer, an easy adhesion layer (adhesion layer) for the purpose of adding further functions under the base material or on the outermost surface layer opposite to the base material. , Antifouling layer, deodorant layer, droplet layer, slippery layer, hard coat layer, wear resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorbing layer, infrared absorbing layer, printed layer, fluorescent light emitting layer, hologram Layer, release layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer), colored layer (visible light absorbing layer), laminated glass other than the high refractive index layer and low refractive index layer of the present invention One or more functional layers such as an intermediate film layer may be included.

Next, the basic configuration outline of the low refractive index layer and the high refractive index layer in the infrared shielding film of the present invention will be described.

[Low refractive index layer and high refractive index layer]
The low refractive index layer and the high refractive index layer of the present invention preferably contain a polyvinyl alcohol resin and further contain metal oxide particles. Here, the polyvinyl alcohol-based resin acts as a binder resin in the low refractive index layer and the high refractive index layer. The low refractive index layer and the high refractive index layer more preferably include metal oxide particles and a polyvinyl alcohol resin.

[Polyvinyl alcohol resin]
In the present invention, the average degree of polymerization of polyvinyl alcohol resin contained in adjacent refractive index layers (low refractive index layer and high refractive index layer) having different refractive indexes (hereinafter simply referred to as “average degree of polymerization of polyvinyl alcohol resin”). Alternatively, the degree of polymerization of the maximum amount of polyvinyl alcohol resin is different. Here, the average degree of polymerization of the polyvinyl alcohol resin or the degree of polymerization of the maximum amount of the polyvinyl alcohol resin may be different between any adjacent refractive index layers (low refractive index layer and high refractive index layer). Therefore, when two refractive index layers B and C are adjacent to one refractive index layer A, the refractive index layer A and at least one of the refractive index layers B or C are between. Therefore, the above relationship may be satisfied. Preferably, the above relationship is satisfied between the refractive index layer A and the refractive index layers B and C adjacent to the refractive index layer A. That is, the present invention is characterized in that the refractive index layer contains a polyvinyl alcohol resin, and the degree of polymerization of the polyvinyl alcohol resin is different from that of at least one adjacent refractive index layer having a different refractive index. It is preferable that the polymerization degree of polyvinyl alcohol resin differs between both adjacent refractive index layers containing alcohol resin and having different refractive indexes. In the present specification, the “average degree of polymerization” of a polyvinyl alcohol resin when the same refractive index layer contains two or more types of polyvinyl alcohol resins is an average value of the degree of polymerization of each polyvinyl alcohol resin. Specifically, it means the sum of contents obtained by multiplying the polymerization degree of each polyvinyl alcohol-based resin when the total amount of polyvinyl alcohol-based resin contained in one refractive index layer is 100% by mass. For example, when the refractive index layer is composed of PVA220 (degree of polymerization = 2200): 25% by mass, PVA235 (degree of polymerization = 3500): 20% by mass and PVA245 (degree of polymerization = 4500): 55% by mass The average degree of polymerization of the resin mixture is 3675 (= 2200 × 0.25 + 3500 × 0.2 + 4500 × 0.55). The “maximum amount of polyvinyl alcohol-based resin contained in the refractive index layer” when the same refractive index layer contains two or more types of polyvinyl alcohol-based resins refers to the polyvinyl alcohol-based resin having the highest content in the same refractive index layer. It means resin. Specifically, in the above case, since the maximum amount of polyvinyl alcohol-based resin contained in the refractive index layer is PVA245, the degree of polymerization of the refractive index layer is 4500.

In the present invention, the average polymerization degree of the polyvinyl alcohol resin contained in the adjacent refractive index layers (low refractive index layer and high refractive index layer) or the polymerization degree of the maximum amount of polyvinyl alcohol resin is different. The difference in the degree of polymerization is not particularly limited, but is preferably 300 or more. That is, the average degree of polymerization or the difference in degree of polymerization between one refractive index layer and at least one of the adjacent refractive index layers is preferably 300 or more. More preferably, the average degree of polymerization or the difference in degree of polymerization between one refractive index layer and at least one of the adjacent refractive index layers is more preferably 400 or more, and even more preferably 1000 or more. , 2000 or more is particularly preferable. The upper limit of the average polymerization degree or the difference in polymerization degree between one refractive index layer and at least one of the adjacent refractive index layers is not particularly limited, but is preferably 4000 or less and preferably 3100 or less. Is more preferable. If there is such a difference, interlayer adhesion can be further improved. In addition, by providing such a polymerization degree difference between adjacent layers, interface disturbance (unevenness) can be suppressed, and the infrared reflectance (infrared shielding rate) can be further increased. Further, the bending resistance of the coating film and the stabilization of the coating solution (coating property) can be improved.

In the present invention, if the average degree of polymerization of the polyvinyl alcohol resin contained in the adjacent refractive index layers (low refractive index layer and high refractive index layer) or the degree of polymerization of the maximum amount of polyvinyl alcohol resin is different, the adjacent refractive index The average degree of polymerization or the degree of polymerization of the layer is not particularly limited. Preferably, the degree of polymerization of the polyvinyl alcohol resin contained in the low refractive index layer is higher than the degree of polymerization of the polyvinyl alcohol resin contained in the high refractive index layer. Thereby, interlayer adhesion can be exhibited more effectively. Moreover, the disorder (unevenness | corrugation) of an interface is suppressed and an infrared reflectance (infrared shielding factor) can be made higher. Furthermore, the flexibility and bending resistance of the coating film and the stabilization (coating property) of the coating solution can be improved.

The polymerization degree of the polyvinyl alcohol-based resin contained in the low refractive index layer and the high refractive index layer is not particularly limited, and the same polymerization degree as that of the binder resin usually used for the refractive index layer can be adopted. Preferably, the polymerization degree of the polyvinyl alcohol-based resin contained in the low refractive index layer and / or the high refractive index layer is 6000 or less, more preferably 5000 or less. That is, the polymerization degree of the polymerization degree of the polyvinyl alcohol resin (unmodified polyvinyl alcohol) contained in one refractive index layer is 6000 or less, more preferably 5000 or less. The degree of polymerization of the polyvinyl alcohol resin (unmodified polyvinyl alcohol) contained in the low refractive index layer and / or the high refractive index layer is more preferably 4500 or less. The lower limit of the degree of polymerization of the polyvinyl alcohol resin contained in the low refractive index layer and / or the high refractive index layer is not particularly limited, but is preferably 500 or more, more preferably 1000 or more, and 1500. More preferably, it is more preferably 2000 or more. When the degree of polymerization is 500 or more, the crack resistance of the coating film is improved and the haze is improved. On the other hand, when it is 6000 or less, the coating solution is stable and the coating property is improved. The degree of polymerization of the polyvinyl alcohol-based resin contained in at least one of the low refractive index layer and the high refractive index layer is preferably included in the above range, but the polyvinyl alcohol contained in both the low refractive index layer and the high refractive index layer. It is preferable that the polymerization degree of the resin is included in the above range.

Here, the degree of polymerization refers to the viscosity average degree of polymerization, and is measured according to JIS-K6726 (1994). After the PVA is completely re-saponified and purified, the intrinsic viscosity [η] measured in water at 30 ° C. It can be obtained from (dl / g) by the following equation.

As a method for comparing the difference in the degree of polymerization in each refractive index layer, when each refractive index layer includes a plurality of polyvinyl alcohol resins having different polymerization degrees, the polyvinyl alcohol resin contained in the refractive index layer A value obtained by averaging the degree of polymerization is adopted as the “degree of polymerization”. For example, when the refractive index layer contains 85% by weight of a polyvinyl alcohol resin having a polymerization degree of 6000 and 15% by weight of a polyvinyl alcohol resin having a polymerization degree of 3500, the polymerization of the polyvinyl alcohol resin contained in the refractive index layer. The degree is “(6000 × 0.85) + (3500 × 0.15) = 5625”. The modified polyvinyl alcohol resin is included in the calculation of the degree of polymerization.

In the infrared shielding film of the present invention, the saponification degree of the polyvinyl alcohol-based resin used for the high refractive index layer and the low refractive index layer may be substantially the same or different. The refractive index layer and the low refractive index layer preferably contain polyvinyl alcohol resins having different saponification degrees. By containing polyvinyl alcohol resins having different saponification degrees in the high refractive index layer and the low refractive index layer, mixing at the interface is suppressed, the infrared reflectance (infrared shielding ratio) is improved, and the haze is increased. Since it becomes low, it is preferable. Either the high refractive index layer or the low refractive index layer may have a higher saponification degree, but the polyvinyl alcohol contained in the high refractive index layer has a higher saponification degree than the polyvinyl alcohol contained in the low refractive index layer. Is more preferable. This is because the metal oxide particles contained in the high refractive index layer can be protected by polyvinyl alcohol having a high degree of saponification.

Further, the difference in absolute value of the saponification degree between the polyvinyl alcohol resin contained in the low refractive index layer and the polyvinyl alcohol resin contained in the high refractive index layer is preferably 3 mol% or more. More preferably, it is 5 mol% or more. If it is such a range, the interlayer mixed state of a high refractive index layer and a low refractive index layer can be made into a favorable state. The upper limit of the difference in the degree of saponification between the polyvinyl alcohol-based resin contained in the low refractive index layer and the polyvinyl alcohol-based resin contained in the high refractive index layer is not particularly limited, but the farther away is the better. Specifically, from the viewpoint of the solubility of polyvinyl alcohol in water, the difference in the saponification degree between the polyvinyl alcohol resin contained in the low refractive index layer and the polyvinyl alcohol resin contained in the high refractive index layer is 20 mol. % Or less is preferable.

Here, the degree of saponification is the ratio of hydroxyl groups to the total number of acetyloxy groups (derived from the starting vinyl acetate) and hydroxyl groups in the polyvinyl alcohol resin.

The polyvinyl alcohol resin for which the difference in the saponification degree in each refractive index layer is compared. When each refractive index layer contains a plurality of polyvinyl alcohol resins (different saponification degrees), the content is the highest in the refractive index layer. It is a high polyvinyl alcohol resin. Here, when the term “polyvinyl alcohol resin having the highest content in the refractive index layer” is used, it is assumed that polyvinyl alcohol resins having a difference in saponification degree of less than 3 mol% are the same polyvinyl alcohol resin. Is calculated. However, a low polymerization degree polyvinyl alcohol resin having a polymerization degree of 1000 or less is a different polyvinyl alcohol resin (if the difference in saponification degree is less than 3 mol%, the same polyvinyl alcohol resin is different. do not do). Specifically, when polyvinyl alcohol resins having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% are respectively contained in the same layer by 10 mass%, 40 mass%, and 50 mass%, These three polyvinyl alcohol resins are the same polyvinyl alcohol resin, and these three mixtures are polyvinyl alcohol resins contained in the low refractive index layer or the high refractive index layer. In addition, the above-mentioned “polyvinyl alcohol resin having a difference in saponification degree of less than 3 mol%” is sufficient if it is less than 3 mol% when attention is paid to any polyvinyl alcohol resin, for example, 90, 91, 92, 94 mol. % Vinyl alcohol-based resin, when paying attention to 91 mol% vinyl alcohol-based resin, since all the polyvinyl alcohol-based resins are less than 3 mol%, the same polyvinyl alcohol-based resin is obtained.

When a polyvinyl alcohol resin 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 alcohol resins, and the saponification degree is 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 is a mixture of PVA 217 to 245 (the difference in the degree of saponification of PVA 217 to 245 is less than 3 mol%, which is the same polyvinyl alcohol resin), and this mixture is contained in the low refractive index layer or the high refractive index layer. The resulting polyvinyl alcohol resin. In the mixture of PVA 217 to 245 (polyvinyl alcohol resin contained in the low refractive index layer or the high refractive index layer), the saponification degree is 88 mol%. Further, the modified polyvinyl alcohol resin is included in the calculation of the saponification degree.

The saponification degree of the polyvinyl alcohol resin contained in the low refractive index layer and the polyvinyl alcohol resin contained in the high refractive index layer is preferably 75 mol% or more from the viewpoint of solubility in water, and is preferably 75 to 99. It is more preferably 5 mol%, and further preferably 80 to 99 mol%. Further, when the saponification degree of the polyvinyl alcohol resin contained in the low refractive index layer and the high refractive index layer is different, the polyvinyl alcohol resin contained in the low refractive index layer and the polyvinyl alcohol resin contained in the low refractive index layer. When one of them has a saponification degree of 90 mol% or more and the other is 90 mol% or less, the intermixed state of the high refractive index layer and the low refractive index layer can be made good. It is more preferable that one of the polyvinyl alcohol resin contained in the low refractive index layer and the polyvinyl alcohol resin contained in the high refractive index layer has a saponification degree of 95 mol% or more and the other is 90 mol% or less. The saponification degree of the polyvinyl alcohol resin contained in the low refractive index layer is more preferably 90 mol% or less, and the saponification degree of the polyvinyl alcohol resin contained in the high refractive index layer is more preferably 95 mol% or more. The upper limit of the saponification degree of the polyvinyl alcohol-based resin is not particularly limited, but is usually less than 100 mol% and about 99.9 mol% or less.

The polyvinyl alcohol resin is preferably a water-soluble polyvinyl alcohol resin (water-soluble binder resin). This is because a stable coating solution can be produced by using a water-soluble polyvinyl alcohol resin. In the present invention, it is preferable to use a polyvinyl alcohol-based resin because the liquid stability of the coating solution for the refractive index layer is excellent, and as a result, the coating property is excellent. In the present specification, “water-soluble” of the polyvinyl alcohol-based resin is a compound that dissolves 1% by mass or more in an aqueous medium, and preferably 3% by mass or more. When there are a plurality of refractive index layers (low refractive index layer or high refractive index layer), the polyvinyl alcohol resins used in each refractive index layer may be the same or different. . Further, the polyvinyl alcohol resins contained in the low refractive index layer and the high refractive index layer may be the same or different.

The form of the polyvinyl alcohol resin is not particularly limited, and a normal polyvinyl alcohol resin obtained by hydrolyzing polyvinyl acetate (unmodified polyvinyl alcohol), a cation-modified polyvinyl alcohol (cation-modified polyvinyl alcohol), an anion And modified polyvinyl alcohol resins such as anion-modified polyvinyl alcohol having a functional group, nonionic modified polyvinyl alcohol having a nonionic group, and modified polyvinyl alcohol modified with acrylic. Further, vinyl acetate resins (for example, “Exeval” manufactured by Kuraray), polyvinyl acetal resins obtained by reacting polyvinyl alcohol with an aldehyde (for example, “ESREC” manufactured by Sekisui Chemical), silanol-modified polyvinyl alcohol having a silanol group (for example, Kuraray "R-1130"), modified polyvinyl alcohol resin having an acetoacetyl group in the molecule (for example, "Gosefimer (registered trademark) Z / WR series" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), etc. It is included in the polyvinyl alcohol resin according to the present invention.

These polyvinyl alcohol resins can be used alone or in combination of two or more kinds such as the degree of polymerization and the kind of modification. From the viewpoint of moisture resistance, it is preferable to contain a modified polyvinyl alcohol resin. That is, it is preferable that at least one of the refractive index layers contains modified polyvinyl alcohol.

The polyvinyl alcohol resin (unmodified polyvinyl alcohol) may be synthesized or a commercially available product may be used. In the latter case, Kuraray Poval PVA series (manufactured by Kuraray Co., Ltd.), J-Poval J series (manufactured by Nippon Vinegar Poval Co., Ltd.) and the like can be used.

Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups or quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol as described in JP-A-61-110483. Polyvinyl alcohol, which is 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, And 1-dimethyl-3-dimethylaminopropyl) acrylamide. The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative 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 is added to a part of vinyl alcohol as described in JP-A-7-9758, and described in JP-A-8-25795. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol.

In addition, as modified polyvinyl alcohol (vinyl alcohol polymer), Exeval (trade name: manufactured by Kuraray Co., Ltd.), Nichigo G polymer (trade name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Goseifamer (registered trademark) Z / WR series (trade name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

Silanol-modified polyvinyl alcohol is not particularly limited, and may be synthesized by a known method or may be a commercially available product. The modification rate of the silanol-modified polyvinyl alcohol is usually 0.01 to 5 mol%, preferably 0.1 to 1 mol%. If the modification rate is less than 0.01 mol%, the water resistance may deteriorate, and if it exceeds 5 mol%, the solubility in water may deteriorate. The silanol-modified polyvinyl alcohol preferably has a saponification degree of 95 mol% or more, more preferably 95.0 to 99.5 mol%, from the viewpoint of scratch resistance and gloss marks. The degree of polymerization of the silanol-modified polyvinyl alcohol is not particularly limited, but the average degree of polymerization is usually 300 to 2,500, preferably 500 to 1,700. When the degree of polymerization is 300 or more, the strength of the coating layer is high, and when the degree of polymerization is 2,500 or less, the viscosity of the coating solution does not become excessively high and is suitable for process.

In the present invention, the content of the polyvinyl alcohol resin (total polyvinyl alcohol resin) is not particularly limited. For example, in the low refractive index layer, the content of the polyvinyl alcohol resin is preferably 5 to 50% by mass, more preferably 10 to 40% by mass with respect to 100% by mass of the total mass (solid content) of each refractive index layer. %, More preferably 14 to 35% by mass. In the high refractive index layer, the content of the polyvinyl alcohol-based resin is preferably 3 to 70% by mass, more preferably 5 to 60% by mass with respect to 100% by mass of the total solid content of the high refractive index layer. The amount is preferably 10 to 50% by mass, particularly preferably 15 to 45% by mass. With such an amount, the film surface is not disturbed during drying after coating the refractive index layer (the film surface becomes uniform), and the obtained infrared shielding film exhibits excellent transparency. Moreover, since the relative content of the metal oxide in the refractive index layer is appropriate, it is easy to increase the refractive index difference between the high refractive index layer and the low refractive index layer. In the present specification, the “film surface” means the surface of the coating film and may also be referred to as “surface”. The “total polyvinyl alcohol resin” means the total amount of polyvinyl alcohol resin contained in each refractive index layer. For example, a low polymerization degree polyvinyl alcohol resin having a polymerization degree of less than 1000 is also included in the content of the total polyvinyl alcohol resin.

[Resin binder (other water-soluble polymers)]
In the present invention, each refractive index layer may contain other resin binder as a resin binder in addition to the polyvinyl alcohol resin.

The content of the resin binder other than the polyvinyl alcohol resin is not particularly limited, but is preferably 5 to 70% by mass, more preferably 5%, based on the total mass (solid content) of each refractive index layer. ~ 50% by weight.

In the present invention, the binder resin is preferably composed of a water-soluble binder resin. This is because the use of the water-soluble binder resin makes it possible to form a refractive index layer without using an organic solvent, which is environmentally preferable. In the present invention, in addition to the polyvinyl alcohol resin, a water-soluble polymer other than the polyvinyl alcohol resin may be used as the binder resin. Here, the water-soluble polymer other than the polyvinyl alcohol-based resin means a G2 glass filter (maximum pore size) when dissolved in water at a concentration of 0.5% by mass at the temperature at which the water-soluble polymer is most dissolved. 40 to 50 μm) means that the mass of the insoluble matter separated by filtration is within 50 mass% of the added water-soluble polymer. Among such water-soluble polymers, gelatin, celluloses, thickening polysaccharides, and polymers having reactive functional groups are particularly preferable. These water-soluble polymers may be used alone or in combination of two or more. The water-soluble polymer may be a synthetic product or a commercial product. In the present invention, it is preferable that the high refractive index layer does not contain gelatin or thickening polysaccharide. The thickening polysaccharide referred to in the present invention is a polymer of saccharides and has many hydrogen bonding groups in the molecule, and the viscosity at low temperature and the viscosity at high temperature due to the difference in hydrogen bonding force between molecules depending on the temperature. It is a polysaccharide with a large difference in characteristics, and when metal oxide fine particles are added, it causes an increase in viscosity that is thought to be due to hydrogen bonding with the metal oxide fine particles at low temperatures.

Specifically, 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, glucolanoglycan (eg, gellan gum), glycosaminoglycan (eg, hyaluronic acid, keratan) Sulfuric acid, etc.), alginic acid and alginates, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, natural macromolecular polysaccharides derived from red algae such as farseleran, L-arabitose, D-ribose, 2-deoxyribose, D-xy Pentoses such as glucose, D-glucose, D-fructose, D-mannose, D-galactose, tamarind seed gum, guar gum, cationized guar gum, hydroxypropyl guar gum, locust bean gum, tara gum, arabinogalactan, gellan gum .

[Metal oxide particles in the low refractive index layer (first metal oxide particles)]
The low refractive index layer of the present invention preferably contains metal oxide particles (first metal oxide particles). Examples of the first metal oxide particles used in the low refractive index layer of the present invention include zinc oxide, silicon dioxide such as synthetic amorphous silica and colloidal silica, alumina, and colloidal alumina. In the present invention, in order to adjust the refractive index, the first metal oxide may be used alone or in combination of two or more.

In the low refractive index layer according to the present invention, silicon dioxide is preferably used as the first metal oxide particles, and colloidal silica is particularly preferably used.

The average particle diameter (number average; diameter) of the first metal oxide particles (preferably silicon dioxide) contained in the low refractive index layer of the present invention is preferably 3 to 100 nm, and preferably 3 to 50 nm. It is more preferable.

In the present specification, the average particle diameter (number average; diameter) of the metal oxide fine particles 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 1,000 arbitrary The particle diameter of each particle is measured and obtained as a 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.

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-60-218904, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 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 WO94 / 26530 pamphlet. Those which are.

Such colloidal silica may be a synthetic product or a commercially available product. Examples of commercially available products include the Snowtex series (Snowtex OS, OXS, S, OS, 20, 30, 40, O, N, C, etc.) sold by Nissan Chemical Industries.

The surface of the colloidal silica may be cation-modified, or may be treated with Al, Ca, Mg, Ba or the like.

The content of the first metal oxide particles in the low refractive index layer is preferably 20 to 75% by mass, and preferably 30 to 70% by mass with respect to 100% by mass of the total solid content of the low refractive index layer. More preferably, the content is 35 to 69% by mass, still more preferably 40 to 68% by mass. When it is 20% by mass or more, a desired refractive index is obtained, and when it is 75% by mass or less, the coatability is good, which is preferable.

In the low refractive index layer of the present invention, the first metal oxide particles may be contained in at least one of the plurality of low refractive index layers.

[Metal oxide particles in the high refractive index layer (second metal oxide particles)]
The high refractive index layer of the present invention preferably contains metal oxide particles (second metal oxide particles). Moreover, it is preferable that the 2nd metal oxide particle which can be contained in a high refractive index layer is a metal oxide particle different from a low refractive index layer.

Examples of the metal oxide particles used in the high refractive index layer according to the present invention include titanium oxide, zirconia, zinc oxide, alumina, colloidal alumina, niobium oxide, europium oxide, and zircon. In the present invention, in order to adjust the refractive index, the second metal oxide may be used alone or in combination of two or more.

In the present invention, in order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer is formed of metal oxide particles having a high refractive index such as titanium oxide and zirconia, that is, titanium oxide particles and zirconia. It is preferable to contain particles. Moreover, it is more preferable to contain rutile (tetragonal) titanium oxide particles having a volume average particle size of 100 nm or less. A plurality of types of titanium oxide particles may be mixed.

In addition, the first metal oxide particles contained in the low refractive index layer and the second metal oxide particles contained in the high refractive index layer are in a state of having ionicity (that is, the electric charges have the same sign). It is preferable. For example, in the case of simultaneous multilayer coating, if the ionicity is different, it reacts at the interface to form aggregates and haze deteriorates. As means for aligning ionicity, for example, when silicon dioxide (anion) is used for the low refractive index layer and titanium oxide (cation) is used for the high refractive index layer, silicon dioxide is treated with aluminum or the like to be cationized, Alternatively, as described later, titanium oxide can be anionized by treatment with a silicon-containing hydrated oxide.

The average particle diameter (number average) of the second metal oxide particles contained in the high refractive index layer of the present invention is preferably 3 to 100 nm, and more preferably 3 to 50 nm.

The second metal oxide particles contained in the high refractive index layer preferably have a volume average particle size of 50 nm or less, more preferably 1 to 45 nm, and even more preferably 5 to 40 nm. . A volume average particle size of 50 nm or less is preferable from the viewpoint of low visible light transmittance and low haze.

Here, the volume average particle diameter is a volume average particle diameter of primary particles or secondary particles dispersed in a medium, and can be measured by a laser diffraction / scattering method, a dynamic light scattering method, or the like.

Specifically, the particles themselves or the particles appearing on the cross section or surface of the refractive index layer are observed with an electron microscope, and the particle diameters of 1,000 arbitrary particles are measured, and d1, d2,. .. In a group of metal oxide particles having n1, n2,..., Nk particles each having a particle size of dk, the volume average particle size when the volume per particle is vi The average particle diameter weighted by the volume represented by mv = {Σ (vi · di)} / {Σ (vi)} is calculated.

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

The content of the metal oxide particles in the high refractive index layer is preferably 15 to 90% by mass, and preferably 20 to 85% by mass with respect to 100% by mass of the total solid content of the high refractive index layer. More preferably, it is 30 to 80% by mass. By setting it as the said range, it can be set as the favorable infrared shielding property.

The titanium oxide particles preferably used as the second metal oxide particles of the present invention are preferably water-based using a titanium oxide sol whose surface is modified so as to be dispersible in water or an organic solvent.

Examples of the preparation method of the aqueous titanium oxide sol include, for example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, JP-A-63-3. Reference can be made to the matters described in Japanese Patent No. 17221.

When titanium oxide particles are used as the second metal oxide particles, for example, “Titanium oxide—physical properties and applied technology” Manabu Seino, p. 255-258 (2000) Gihodo Publishing Co., Ltd. Alternatively, the method of step (2) described in paragraph numbers “0011” to “0023” of WO2007 / 039953 can be referred to.

In the production method according to the above step (2), titanium dioxide hydrate is treated with at least one basic compound selected from the group consisting of alkali metal hydroxides or alkaline earth metal hydroxides. After the step (1), the titanium dioxide dispersion obtained comprises a step (2) of treating with a carboxylic acid group-containing compound and an inorganic acid.

The second metal oxide particles of the present invention are preferably in the form of core-shell particles in which titanium oxide particles are coated with a silicon-containing hydrated oxide. As the core-shell particles, the volume average particle diameter of the titanium oxide particles as the core part is preferably more than 1 nm and 50 nm or less, more preferably 4 nm or more and 40 nm or less, and the surface of the titanium oxide particles is the titanium oxide that becomes the core. This is a structure in which a shell made of silicon-containing hydrated oxide is coated such that the coating amount of silicon-containing hydrated oxide is 3 to 30% by mass as SiO _{2 with} respect to 100% by mass. In the present invention, by including the core-shell particles as the second metal oxide particles, the high refractive index layer and the low refractive index layer are obtained by the interaction between the silicon-containing hydrated oxide of the shell layer and the polyvinyl alcohol resin. There is an effect that inter-layer mixing is suppressed.

In the present specification, the silicon-containing hydrated oxide may be either a hydrate of an inorganic silicon compound, a hydrolyzate of an organic silicon compound, and / or a condensate. More preferably. Therefore, in the present invention, the second metal oxide particles are preferably silica-modified (silanol-modified) titanium oxide particles in which the titanium oxide particles are silica-modified.

The coating amount of the silicon-containing hydrated compound of titanium oxide is 3 to 30% by mass, preferably 3 to 10% by mass, more preferably 3 to 8% by mass with respect to 100% by mass of titanium oxide. This is because when the coating amount is 30% by mass or less, a desired refractive index of the high refractive index layer can be obtained, and when the coating amount is 3% by mass or more, particles can be stably formed.

Moreover, as the second metal oxide particles of the present invention, core-shell particles produced by a known method can be used. For example, the following (i) to (iv); (i) an aqueous solution containing titanium oxide particles is heated and hydrolyzed, or an aqueous solution containing titanium oxide particles is neutralized by adding an alkali to obtain an average particle size. After obtaining 1 to 30 nm of titanium oxide, the titanium oxide particles and the mineral acid were mixed so that the molar ratio of titanium oxide particles / mineral acid was in the range of 1 / 0.5 to 1/2. The slurry is heat-treated at a temperature not lower than the boiling point of the slurry and not higher than the boiling point of the slurry, and then a silicon compound (for example, an aqueous sodium silicate solution) is added to the obtained slurry containing the titanium oxide particles. (Ii) Hydrous titanium oxide; (ii) Hydrous titanium oxide; Precipitating silicon hydrated oxide on the surface and then treating the surface, and then removing impurities from the resulting slurry of the surface treated titanium oxide particles (Japanese Patent Laid-Open No. 10-158015); A method of neutralizing by mixing a titanium oxide sol stabilized at a pH in an acidic range obtained by peptizing a monobasic acid or a salt thereof with an alkyl silicate as a dispersion stabilizer by a conventional method ( (Iii) Hydrogen peroxide and tin metal are maintained at a H ₂ O ₂ / Sn molar ratio of 2 to 3 at the same time or alternately, such as a titanium salt (eg, titanium tetrachloride). The mixture is added to the aqueous solution to form a basic salt aqueous solution containing titanium, and the basic salt aqueous solution is kept at a temperature of 50 to 100 ° C. for 0.1 to 100 hours to coagulate the composite colloid containing titanium oxide. Aggregates are formed and the electrolyte in the aggregate slurry is then removed to produce a stable aqueous sol of composite colloidal particles comprising titanium oxide. On the other hand, a stable aqueous sol of composite colloidal particles containing silicon dioxide is produced by preparing an aqueous solution containing silicate (eg, sodium silicate aqueous solution) and removing cations present in the aqueous solution. Is done. The obtained composite aqueous sol containing titanium oxide is converted to 100 parts by mass in terms of metal oxide TiO ₂ , and the obtained composite aqueous sol containing silicon dioxide is converted to 2 to 100 in terms of metal oxide SiO _2. A method of mixing with parts by mass and removing anions, followed by heating and aging at 80 ° C. for 1 hour (Japanese Patent Laid-open No. 2000-063119); (iv) Hydrous titanic acid by adding hydrogen peroxide to hydrous titanic acid gel or sol In the resulting peroxotitanic acid aqueous solution, a silicon compound or the like is added and heated to obtain a dispersion of core particles composed of a complex solid solution oxide having a rutile structure, and then the dispersion of the core particles After adding a silicon compound or the like, a coating layer is formed on the surface of the core particles by heating to obtain a sol in which the composite oxide particles are dispersed, followed by heating (Japanese Patent Laid-Open No. 2000-204301); The hydrous titanium oxide hydrosol titanium oxide obtained by peptization, organoalkoxysilane (R ¹ nSiX _4-n) or hydrogen peroxide and an aliphatic or compounds selected from aromatic hydroxycarboxylic acid as a stabilizer And the core-shell particles produced by the desalting treatment after adjusting the pH of the solution to 3 to less than 9 and aging (Japanese Patent No. 4550753).

The core-shell particle according to the present invention may be one in which the entire surface of the titanium oxide particle as the core is coated with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particle as the core is covered with a silicon-containing water. What coated with the sum oxide may be used.

[Curing agent]
The low refractive index layer and / or the high refractive index layer of the present invention may contain a curing agent. This is because the curing agent can react with the polyvinyl alcohol-based resin to form a hydrogen bond network. In addition, when a polyvinyl alcohol resin or silanol-modified polyvinyl alcohol is used as the binder resin, the effect can be exhibited particularly.

In the present invention, the curing agent that can be used together with the polyvinyl alcohol-based resin (or silanol-modified polyvinyl alcohol) is not particularly limited as long as it causes a curing reaction with the polyvinyl alcohol-based resin, but boric acid, boric acid It is preferably selected from the group consisting of salt and borax. In addition to boric acid, borate, and borax, known materials can be used, and in general, a compound having a group capable of reacting with a polyvinyl alcohol resin or a reaction between different groups of a polyvinyl alcohol resin is promoted. And are appropriately selected and used. 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 or borate refers to oxyacids and salts thereof having a boron atom as a central atom, and specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaborate. Boric acid and their salts.

Borax is a mineral represented by Na ₂ B ₄ O ₅ (OH) ₄ .8H ₂ O (decahydrate of sodium tetraborate Na ₂ B ₄ O ₇ ).

Boric acid having a boron atom, borate, and borax as a curing agent may be used alone or as a mixture of two or more. An aqueous solution of boric acid or a mixed aqueous solution of boric acid and borax is preferred. The aqueous solutions of boric acid and borax can be added only in relatively dilute aqueous solutions, respectively, but by mixing them both can be made into a concentrated aqueous solution 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 preferable to use boric acid and a salt thereof and / or borax in order to obtain the effects of the present invention. When boric acid and its salt and / or borax are used, the metal oxide particles and the OH group of the polyvinyl alcohol resin form a hydrogen bond network, and as a result, the high refractive index layer and the low refractive index layer It is considered that the interlayer mixing is suppressed and preferable infrared shielding properties are achieved. In particular, when a multilayer coating of a high refractive index layer and a low refractive index layer is applied with a coater, the film surface temperature of the coating film is once cooled to about 15 ° C., and then the set surface coating process is used to dry the film surface. Can express an effect more preferably.

The total amount of the curing agent used is 1 to 1 per 1 g of binder resin (the total amount of polyvinyl alcohol resin and silanol modified polyvinyl alcohol when a polyvinyl alcohol resin or silanol modified polyvinyl alcohol is also used). 600 mg is preferable, and 100 to 600 mg is more preferable.

〔Base material〕
The base material used for the infrared shielding film of the present invention is not particularly limited as long as it is formed of a transparent organic material.

Examples of such a substrate include methacrylic acid ester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyarylate, polystyrene (PS), aromatic polyamide, polyether ether ketone, polysulfone. , A film made of a resin such as polyethersulfone, polyimide, or polyetherimide, and a resin film obtained by laminating two or more layers of the resin. From the viewpoint of cost and availability, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC) and the like are preferably used.

The thickness of the substrate is preferably about 5 to 200 μm, more preferably 15 to 150 μm. Two or more substrates may be stacked, and in this case, the types of the substrates may be the same or different.

Further, the substrate preferably has a visible light region transmittance of 85% or more as shown in JIS R3106 (1998), particularly preferably 90% or more (upper limit: 100%). Advantageous in that the transmittance of the visible light region indicated by JIS R3106 (1998) is 50% or more (upper limit: 100%) when the base material is above the above transmittance. It is preferable.

In addition, the base material using the resin or the like may be an unstretched film or a stretched film. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression.

The base material can be manufactured by a conventionally known general method. For example, an unstretched substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the unstretched base material is subjected to a known method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular-type simultaneous biaxial stretching, or the flow direction of the base material (vertical axis), or A stretched substrate can be produced by stretching in the direction perpendicular to the flow direction of the substrate (horizontal axis). The draw ratio in this case can be appropriately selected according to the resin as the raw material of the base material, but is preferably 2 to 10 times in each of the vertical axis direction and the horizontal axis direction.

Also, the base material may be subjected to relaxation treatment or offline heat treatment in terms of dimensional stability. It is preferable that the relaxation treatment is performed in the 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 of 80 to 200 ° C., more preferably a treatment temperature of 100 to 180 ° C. In addition, the relaxation rate is preferably in the range of 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is 2 to 6%. The relaxed base material is subjected to the following off-line heat treatment to improve heat resistance and to improve dimensional stability.

It is preferable that the substrate is coated with the undercoat layer coating solution inline on one side or both sides during the film forming process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating. 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 alcohol resins. , Modified polyvinyl alcohol resin, gelatin and the like, 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 coated by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating. The coating amount of the undercoat layer is preferably about 0.01 to 2 g / m ² (dry state).

[Infrared shielding film manufacturing method]
There is no restriction | limiting in particular about the manufacturing method of the infrared shielding film of this invention, As long as at least 1 unit comprised from a high-refractive-index layer and a low-refractive-index layer can be formed on a base material, what kind of thing The method can also be used.

In the method for producing an infrared shielding film of the present invention, a laminate (unit) composed of a high refractive index layer and a low refractive index layer is laminated on a substrate, for example, a coating for a high refractive index layer. The laminate and the coating solution for the low refractive index layer are alternately applied and dried to form a laminate. That is, a coating solution for a low refractive index layer containing desired components (for example, metal oxide particles, polyvinyl alcohol-based resin and solvent), and desired components (for example, metal oxide particles, polyvinyl alcohol-based resin and solvent) ) Containing a coating solution for a high refractive index layer, and a step of drying the substrate coated with the coating solution.

Specifically, it is preferable that a high refractive index layer and a low refractive index layer are alternately applied and dried to form a laminate. Specific examples include: (1) A high refractive index layer coating solution is applied on a substrate and dried to form a high refractive index layer, and then a low refractive index layer coating solution is applied. And then drying to form a low refractive index layer to form an infrared shielding film; (2) After applying a low refractive index layer coating solution on a substrate and drying to form a low refractive index layer A method for forming a high refractive index layer by applying a coating solution for a high refractive index layer and drying; and (3) forming an infrared shielding film; and (3) a coating solution for a high refractive index layer and a low refractive index on a substrate. A method of forming an infrared shielding film including a high refractive index layer and a low refractive index layer by alternately applying successive coating layers with the coating liquid for the refractive index layer and then drying; (4) High refractive index on the substrate A method of forming an infrared shielding film including a high refractive index layer and a low refractive index layer by simultaneously applying a multilayer coating solution and a low refractive index layer coating solution, followed by drying; Etc., and the like. Among these, the method (4), which is a simpler manufacturing process, is preferable. In addition, in the case of simultaneous multilayer coating, interfacial mixing is more likely to occur, and therefore the present invention is more effective when manufactured by simultaneous multilayer coating.

(Method for preparing coating solution)
First, a method for preparing a coating solution for a high refractive index layer and a coating solution for a low refractive index layer will be described.

The method for preparing the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer is not particularly limited, and for example, metal oxide particles, polyvinyl alcohol resin, other binder resins, and are added as necessary. A method of adding other additives and stirring and mixing them may be mentioned. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed at one time while stirring. If necessary, it is further adjusted to an appropriate viscosity using a solvent.

The second metal oxide particles contained in the coating solution for the refractive index layer, particularly the coating solution for the high refractive index layer, should be prepared separately in a dispersion state before preparing the coating solution. Is preferred. That is, it is preferable to form the high refractive index layer using an aqueous high refractive index coating solution prepared by adding and dispersing rutile type titanium oxide having a volume average particle size of 100 nm or less. Furthermore, in the present invention, a high refractive index layer is formed using an aqueous high refractive index layer coating solution prepared by adding and dispersing titanium oxide particles coated with a silicon-containing hydrated oxide by the method described above. More preferably, it is formed. In the case of using a dispersion liquid, the dispersion liquid may be appropriately added so as to have an arbitrary concentration in each layer.

The solvent for preparing the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable. In the present invention, an aqueous solvent can be used because a polyvinyl alcohol resin is mainly used as the resin binder. Compared to the case where an organic solvent is used, the aqueous solvent does not require a large-scale production facility, so that it is preferable in terms of productivity and also in terms of environmental conservation.

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, Examples thereof include ethers such as propylene 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. From the viewpoint of environment and simplicity of operation, the solvent of the coating solution is preferably an aqueous solvent, more preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and water is particularly preferable.

In addition, the coating liquid for the low refractive index layer and the coating liquid for the high refractive index layer include a water-soluble resin such as polyvinyl alcohol, water or the It is preferable to use an aqueous coating solution mainly composed of an aqueous solvent containing a water-soluble organic solvent.

The concentration of the binder resin (for example, polyvinyl alcohol resin) in the coating solution for the high refractive index layer is preferably 0.5 to 10% by mass. The concentration of the metal oxide particles in the coating solution for the high refractive index layer is preferably 1 to 50% by mass.

The concentration of the binder resin (for example, polyvinyl alcohol resin) in the coating solution for the low refractive index layer is preferably 0.5 to 10% by mass. The concentration of the metal oxide particles in the coating solution for the low refractive index layer is preferably 1 to 50% by mass.

The viscosity of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer at the time of simultaneous multilayer coating is in the range of 5 to 100 mPa · s when the slide bead coating method is used. Is more preferable, and the range of 10 to 50 mPa · s is more preferable. When the curtain coating method is used, the viscosity at 45 ° C. is preferably in the range of 5 to 1200 mPa · s, more preferably in the range of 25 to 500 mPa · s.

The viscosity of the coating solution at 15 ° C. is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, still more preferably 3,000 to 30,000 mPa · s, and most preferably 10 , 30,000 to 30,000 mPa · s.

As a coating and drying method, the coating solution for high refractive index layer and the coating solution for low refractive index layer are heated to 30 ° C. or more, and after coating, the temperature of the formed coating film is set to 1 to 15 ° C. It is preferably cooled once and dried at 10 ° C. or higher, and more preferably, the drying conditions are wet bulb temperature 5 to 50 ° C. and film surface temperature 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 formed coating-film uniformity.

As the coating method, for example, roll coating method, rod bar coating method, air knife coating method, spray coating method, curtain coating method, US Pat. No. 2,761,419, US Pat. No. 2,761,791 The slide bead coating method using the hopper described in 1), the extrusion coating method and the like are preferably used.

(Coating and drying method)
The conditions for the coating and drying method are not particularly limited. For example, in the case of the sequential coating method, first, one of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer heated to 30 to 60 ° C. One is coated on a substrate and dried to form a layer, and then the other coating liquid is coated on this layer and dried to form a laminated film precursor (unit). Next, the number of units necessary for expressing the desired infrared shielding performance is sequentially applied and dried by the above method to obtain a laminated film precursor. When drying, it is preferable to dry the formed coating film at 30 ° C. or higher. For example, drying is preferably performed in the range of a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 30 to 100 ° C. (preferably 10 to 50 ° C.). For example, hot air of 40 to 60 ° C. is blown for 1 to 5 seconds. dry. As a drying method, warm air drying, infrared drying, and microwave drying are used. Further, drying in a multi-stage process is preferable to drying in a single process, and it is more preferable to set the temperature of the constant rate drying section <the temperature of the decremental drying section. In this case, the temperature range of the constant rate drying section is preferably 30 to 60 ° C., and the temperature range of the decreasing rate drying section is preferably 50 to 100 ° C.

The conditions of the coating and drying method when performing simultaneous multilayer coating are as follows. The coating solution for the high refractive index layer and the coating solution for the low refractive index layer are heated to 30 to 60 ° C., and the high refractive index is applied onto the substrate. After the simultaneous multilayer coating of the layer coating solution and the low refractive index layer coating solution, 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. Is preferred. More preferable drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. For example, it is dried by blowing warm air at 80 ° C. for 1 to 5 seconds. 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.

Here, the set means that the viscosity of the coating composition is increased by means such as lowering the temperature by applying cold air or the like to the coating film, the fluidity of the substances in each layer and in each layer is reduced, or the gel It means the process of converting. 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.

The time (setting time) from the time of application until the setting is completed by applying cold air is preferably within 5 minutes, and more preferably within 2 minutes. Further, the lower limit time is not particularly limited, but it is preferable to take 45 seconds or more. With such a set time, the components in the layer can be sufficiently mixed, the interlayer diffusion of the metal oxide fine particles can be suppressed, and the difference in refractive index between the high refractive index layer and the low refractive index layer can be sufficiently taken. If the intermediate layer between the high-refractive index layer and the low-refractive index layer is highly elastic, the setting step may not be provided.

The set time can be adjusted by adjusting the concentration of polyvinyl alcohol resin (binder resin) and metal oxide particles, various known gelling agents such as gelatin, pectin, agar, carrageenan, gellan gum, etc. It can adjust by adding the component of.

The temperature of the cold air is preferably 0 to 25 ° C, more preferably 5 to 10 ° C. The time for which the coating film is exposed to cold air is preferably 10 to 360 seconds, more preferably 10 to 300 seconds, and further preferably 10 to 120 seconds, although it depends on the transport speed of the coating film.

What is necessary is just to apply | coat so that the coating thickness of the coating liquid for high refractive index layers and the coating liquid for low refractive index layers may become the preferable thickness at the time of drying as shown above.

[Infrared shield]
The infrared shielding film provided by the present invention can be applied to a wide range of fields. For example, pasting to facilities exposed to sunlight for a long time, such as outdoor windows of buildings and automobile windows, films for window pasting such as infrared shielding films that give an infrared shielding effect, films for agricultural greenhouses, etc. As, it is mainly used for the purpose of improving the weather resistance.

Particularly, it is suitable for a member in which the infrared shielding film according to the present invention is bonded to a substrate such as glass or a glass substitute resin directly or via an adhesive.

That is, according to still another embodiment of the present invention, there is also provided an infrared shielding body in which the infrared shielding film according to the present invention is provided on at least one surface of a substrate.

Specific examples of the substrate include, for example, glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, melamine resin, Examples thereof include phenol resin, diallyl phthalate resin, polyimide resin, urethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, vinyl chloride resin, metal plate, ceramic and the like. The type of resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and two or more of these may be used in combination. The substrate that can be used in the present invention can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding and the like. The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

The adhesive layer or adhesive layer that bonds the infrared shielding film and the substrate is preferably provided with the infrared shielding film on the sunlight (heat ray) incident surface side. In addition, it is preferable to sandwich the infrared shielding film according to the present invention between a window glass and a substrate because it can be sealed from surrounding gas such as moisture and has excellent durability. Even if the infrared shielding film according to the present invention is installed outdoors or outside a car (for external application), it is preferable because of environmental durability.

As the adhesive applicable to the present invention, an adhesive mainly composed of a photocurable or thermosetting resin can be used.

The adhesive preferably has durability against ultraviolet rays, and is preferably an acrylic adhesive or a silicone adhesive. Furthermore, an acrylic adhesive is preferable from the viewpoint of adhesive properties and cost. In particular, a solvent system is preferable in the acrylic pressure-sensitive adhesive because the peel strength can be easily controlled. When a solution polymerization polymer is used as the acrylic solvent-based pressure-sensitive adhesive, known monomers can be used as the monomer.

Further, a polyvinyl butyral resin or an ethylene-vinyl acetate copolymer resin used as an intermediate layer of laminated glass may be used. Specifically, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont, Takeda Pharmaceutical Company Limited, duramin), modified ethylene-vinyl acetate copolymer (Mersen G, manufactured by Tosoh Corporation). In addition, you may add and mix | blend an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, coloring, an adhesion adjusting agent etc. suitably in a contact bonding layer.

The heat insulation performance and solar heat shielding performance of infrared shielding films or infrared shields are generally JIS R 3209-1998 (multi-layer glass), JIS R 3106-1998 (transmittance / reflectance / emissivity of sheet glass).・ Test method for solar heat acquisition rate), JIS R 3107-1998 (calculation method of thermal resistance of plate glass and heat transmissivity in architecture).

Measure solar transmittance, solar reflectance, emissivity, and visible light transmittance. (1) Using a spectrophotometer with a wavelength (300 to 2500 nm), measure the spectral transmittance and spectral reflectance of various single glass plates. The emissivity is measured using a spectrophotometer having a wavelength of 5.5 to 50 μm. In addition, a predetermined value is used for the emissivity of float plate glass, polished plate glass, mold plate glass, and heat ray absorbing plate glass. (2) For calculating the solar transmittance, solar reflectance, solar absorption rate, and modified emissivity, the solar transmittance, solar reflectance, solar absorption rate, and vertical emissivity are calculated according to JIS R 3106-1998. The corrected emissivity is obtained by multiplying the vertical emissivity by the coefficient shown in JIS R 3107-1998. The heat insulation and solar heat shielding properties are calculated by (1) calculating the thermal resistance of the multi-layer glass according to JIS R 3209-1998 using the measured thickness value and the corrected emissivity. However, when the hollow layer exceeds 2 mm, the gas thermal conductance of the hollow layer is obtained according to JIS R 3107-1998. (2) The heat insulation is obtained by adding a heat transfer resistance to the heat resistance of the double-glazed glass and calculating the heat flow resistance. (3) The solar heat shielding property is calculated by obtaining the solar heat acquisition rate according to JIS R 3106-1998 and subtracting it from 1.

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 otherwise indicated, "mass part" or "mass%" is represented.

<Production of infrared shielding film>
[Example 1]
(Preparation of coating liquid L1 for low refractive index layer)
The following materials were added in the following composition while being heated to 40 ° C. with stirring in order to prepare a coating solution L1 for a low refractive index layer.

(Preparation of coating liquid H1 for high refractive index layer)
30 L of an aqueous sodium hydroxide solution (concentration: 10 mol / L) was added to 10 L (liter) of an aqueous suspension (TiO ₂ concentration: 100 g / L) in which titanium dioxide hydrate was suspended in water with stirring. The mixture was heated to 90 ° C., aged for 5 hours, neutralized with hydrochloric acid, filtered, and washed with water. In the above reaction (treatment), titanium dioxide hydrate was 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 TiO ₂ concentration was 20 g / L, and 0.4 mol% of citric acid was added to the amount of TiO ₂ with stirring, and the temperature was raised. When the liquid temperature reached 95 ° C., concentrated hydrochloric acid was added to a hydrochloric acid concentration of 30 g / L, and the mixture was stirred for 3 hours while maintaining the liquid temperature.

When the pH and zeta potential of the obtained titanium oxide sol aqueous dispersion were measured, the pH was 1.4 and the zeta potential was +40 mV. Furthermore, when the particle size was measured by Zetasizer Nano manufactured by Malvern, the volume average particle size was 35 nm, and the monodispersity was 16%.

1 kg of pure water was added to 1 kg of a 20.0 mass% titanium oxide sol aqueous dispersion containing rutile type titanium oxide particles having a volume average particle size of 35 nm.

Preparation SiO ₂ concentration of silicate solution to prepare a 2.0 wt% aqueous solution silicate.

-Preparation of silica-modified titanium oxide particles 2 kg of pure water was added to 0.5 kg of the 10.0 mass% titanium oxide sol aqueous dispersion described above, and then heated to 90 ° C. Thereafter, 1.3 kg of a 2.0 mass% aqueous silicic acid solution was gradually added, and then the obtained dispersion was subjected to heat treatment at 175 ° C. for 18 hours in an autoclave, and further concentrated, so that the core was a rutile type. A sol water dispersion (silica-modified titanium oxide particle aqueous dispersion) of 20 mass% silica-modified titanium oxide particles having a structure of titanium oxide and a coating layer of SiO ₂ was obtained.

Then, the following materials were added with the following composition while being heated to 40 ° C. with stirring in order to prepare a coating solution H1 for a high refractive index layer.

(Preparation of sample 1)
Using the slide hopper coating apparatus capable of coating 15 layers in layers after the coating liquids obtained above (the coating liquid L1 for the low refractive index layer and the coating liquid H1 for the high refractive index layer) were stagnated for 10 hours, On the 50 μm thick polyethylene terephthalate film (Toyobo A4300: double-sided easy-adhesion layer, length 200 m × width 210 mm) heated to 40 ° C., and the lowermost layer and the uppermost layer are low refractive index layers, Other than that, a total of 15 layers were simultaneously applied so that the film thickness at the time of drying was 1510 nm, the low refractive index layer was 150 nm, and the high refractive index layer was 150 nm. .

Immediately after application, 5 ° C. cold air was blown to 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 a multi-layer coated product consisting of 15 layers.

Further, a 15-layer coating was applied to the back surface of the 15-layer coating product to prepare Sample 1 consisting of 30 layers on both sides.

[Example 2]
In Example 1, polyvinyl alcohol (PVA224, degree of polymerization: 2400, degree of saponification: 88 mol%, manufactured by Kuraray Co., Ltd.) was used instead of polyvinyl alcohol (JP-33, manufactured by Nippon Vinegar Poval Co., Ltd.). Sample 2 was prepared in the same manner as in Example 1 except that the coating liquid H2 for the high refractive index layer was prepared.

[Example 3]
In Example 2, instead of polyvinyl alcohol (PVA235, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (JP-20, degree of polymerization: 2000, degree of saponification: 88 mol%, manufactured by Nihon Vineyard Poval Co., Ltd.) was used. Then, Sample 3 was produced in the same manner as in Example 2 except that the coating liquid L2 for low refractive index layer was produced.

[Example 4]
In Example 1, instead of polyvinyl alcohol (JP-33, manufactured by Nippon Vinegar Pover Co., Ltd.), polyvinyl alcohol (JP-20, degree of polymerization: 2000, degree of saponification: 88 mol%, Nippon Vinegar Pover ( Sample 4 was produced in the same manner as in Example 1 except that the coating liquid H3 for the high refractive index layer was produced.

[Example 5]
In Example 2, polyvinyl alcohol (JP-45, degree of polymerization: 4500, degree of saponification: 88 mol%, made by Nippon Vineyard Poval Co., Ltd.) was used instead of polyvinyl alcohol (PVA235, manufactured by Kuraray Co., Ltd.). Sample 5 was prepared in the same manner as in Example 2 except that the coating liquid L3 for the low refractive index layer was prepared.

[Example 6]
In Example 5, instead of polyvinyl alcohol (PVA224, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (JP-15, degree of polymerization: 1500, degree of saponification: 88 mol%, manufactured by Nihon Vineyard Poval Co., Ltd.) was used. Sample 6 was prepared in the same manner as in Example 5 except that the coating liquid H4 for the high refractive index layer was prepared.

[Example 7]
In Example 5, instead of polyvinyl alcohol (PVA224, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA205, degree of polymerization: 500, degree of saponification: 88 mol%, manufactured by Kuraray Co., Ltd.) was used. Sample 7 was prepared in the same manner as in Example 5 except that the layer coating solution H5 was prepared.

[Example 8]
In Example 5, except that the simultaneous multilayer coating was performed so that the thickness of the lowermost layer when dried was 150 nm (that is, the thickness of all refractive index layers when dried was 150 nm). Sample 8 was produced in the same manner as in Example 5.

[Example 9]
In Example 5, instead of polyvinyl alcohol (PVA224, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (Gosephemer Z-410, polymerization degree: 2300, saponification degree: 98 mol%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) Sample 9 was prepared in the same manner as in Example 5 except that the coating liquid H6 for the high refractive index layer was prepared using

[Example 10]
In Example 5, instead of polyvinyl alcohol (PVA224, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA124, polymerization degree: 2400, saponification degree: 98.5 mol%, manufactured by Kuraray Co., Ltd.) was used. A sample 10 was produced in the same manner as in Example 5 except that the refractive index layer coating solution H7 was produced.

[Example 11]
(Preparation of coating liquid L4 for low refractive index layer)
In Example 1 (low refractive index layer coating liquid L1), instead of polyvinyl alcohol (PVA235, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (JP-60, polymerization degree: 6000, saponification degree: 88 mol%, Japanese vinegar) A low-refractive-index layer coating solution L4 was produced in the same manner as in Example 1, except that Bi Poval Co., Ltd. was used.

(Preparation of coating liquid H8 for high refractive index layer)
In Example 1 (high refractive index coating solution H1), polyvinyl alcohol (PVA235, polymerization degree: 3500, saponification degree: 88 mol) was used instead of polyvinyl alcohol (JP-33, manufactured by Nippon Bibi-Poval Co., Ltd.). %, Manufactured by Kuraray Co., Ltd.), a high refractive index layer coating solution H8 was prepared in the same manner as in Example 1.

(Preparation of sample 11)
In Example 1, the low refractive index layer coating liquid L4 instead of the low refractive index layer coating liquid L1, and the high refractive index layer coating liquid H8 instead of the high refractive index layer coating liquid H1. Sample 11 was produced in the same manner as in Example 1 except that each was used.

[Example 12]
(Preparation of coating liquid L5 for low refractive index layer)
After adding 10 parts by weight of a 3% by weight boric acid aqueous solution to 45 parts by weight of the following 10% by weight fluorine-containing polymer 1 aqueous solution, the mixture is heated to 45 ° C. and stirred with polyvinyl alcohol (JC-25 (degree of polymerization 2500, saponification). Degree 99.5 mol%, manufactured by Nihon Vinegar & Poval Co., Ltd.) 40 mass parts of 5 mass% aqueous solution, 1 mass part of 1 mass% aqueous solution of surfactant (Lapisol A30, manufactured by NOF Corporation) was added, and 2 mass of pure water. Part was added to prepare a coating solution L5 for a low refractive index layer.

(Preparation of fluoropolymer 1 aqueous solution)
In a 1 L flask equipped with a reflux condenser under a nitrogen atmosphere, 6.4 g of 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate, 26.4 g of methoxypolyethylene glycol # 1000 methacrylate, and 34.9 g of methyl The methacrylate was added to a mixed solvent of 150 ml of isopropanol and 100 ml of pure water. After stirring at room temperature for 1 hour, 1.2 g of ammonium persulfate dissolved in 10 ml of pure water was added, and the mixture was heated and stirred at 65 ° C. for 16 hours. After cooling the obtained reaction mixture, isopropanol was distilled off with a rotary evaporator, and pure water was further added to prepare a 10% by mass aqueous solution containing a fluoropolymer 1. It was 16,000 when molecular weight was measured using GPC.

(Preparation of coating liquid H9 for high refractive index layer)
While 80 parts by mass of a 5% by mass aqueous solution of polyvinyl alcohol (PVA217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.) is heated and stirred at 45 ° C., a surfactant (RAPIDOL A30, NOF Corporation) 1 part by mass of 1% by weight aqueous solution (manufactured) and 19 parts by mass of pure water were added to prepare a coating solution H9 for a high refractive index layer.

(Preparation of sample 12)
In Example 1, the low refractive index layer coating liquid L5 is used instead of the low refractive index layer coating liquid L1, and the high refractive index layer coating liquid H9 is used instead of the high refractive index layer coating liquid H1. Sample 12 was produced in the same manner as in Example 1 except that each was used.

[Example 13]
(Preparation of coating liquid L6 for low refractive index layer)
After adding 10 parts by weight of a 3% by weight boric acid aqueous solution to 45 parts by weight of the 10% by weight fluorine-containing polymer 1 aqueous solution, the mixture was heated to 45 ° C. and stirred while being stirred with polyvinyl alcohol (JC-25 (degree of polymerization 2500, saponification). Degree 99.5 mol%, manufactured by Nihon Acetate Bi-Poval), JM-17 (degree of polymerization 1700, degree of saponification 96.4 mol%, Nihon Acetate-Poval), JP-15 (degree of polymerization 1500, saponification) 40 mass parts of 5 mass% aqueous solution of 86: 5: 9 (solid content mass ratio)) and surfactant (rapizole A30, manufactured by NOF Corporation). 1 parts by weight of a 1% by weight aqueous solution was added, and 2 parts by weight of pure water was added to prepare a coating solution L6 for a low refractive index layer.

(Preparation of Sample 13)
In Example 1, the low refractive index layer coating liquid L6 is used instead of the low refractive index layer coating liquid L1, and the high refractive index layer coating liquid H9 is used instead of the high refractive index layer coating liquid H1. Sample 13 was prepared in the same manner as in Example 1 except that each was used.

[Example 14]
(Preparation of coating liquid H10 for high refractive index layer)
Instead of a 5% by weight aqueous solution of polyvinyl alcohol (JP-33) in the coating liquid H1 for the high refractive index layer, polyvinyl alcohol (JC-25 (polymerization degree 2500, saponification degree 99.5 mol%, manufactured by Nihon Vineyard-Povar) ), JM-17, polymerization degree 1700, saponification degree 96.4 mol%, manufactured by Nihon Acetate Bi-Poval) and JP-15 (polymerization degree 1500, saponification degree 89.8 mol%, manufactured by Nihon Acetate Bi-Poval) ), JP-33 (polymerization degree 3300, saponification degree 86.7 mol%, manufactured by Nihon Acetate Bipoval), and JE-18E (polymerization degree 1800, saponification degree 83.5 mol%, manufactured by Nihon Acetate Bipoval) ) And JL-25E (polymerization degree 2500, saponification degree 79.5 mol%, manufactured by Nihon Acetate / Poval) 10: 25: 25: 13: 13: 14 (solid content mass ratio)) 5% by weight water soluble Besides using the in the same manner as the high-refractive index layer coating solution H1 was prepared a high refractive index layer coating solution H10.

(Preparation of sample 14)
A sample 14 was produced in the same manner as in Example 1, except that the high refractive index layer coating solution H10 was used instead of the high refractive index layer coating solution H1.

[Example 15]
(Preparation of sample 15)
In Example 3, Sample 15 was prepared in the same manner as in Example 3 except that the lowermost layer was coated so that the film thickness when dried was 2250 nm.

[Example 16] (Preparation of Sample 16)
In Example 3, Sample 16 was prepared in the same manner as in Example 3, except that coating was performed so that the thickness of the lowermost layer when dried was 3000 nm.

[Example 17] (Preparation of Sample 17)
In Example 3, Sample 17 was prepared in the same manner as in Example 3 except that the lowermost layer was coated so that the film thickness when dried was 750 nm.

[Example 18]
(Preparation of coating solution L7 for low refractive index layer)
Instead of a 5% by mass aqueous solution of polyvinyl alcohol (PVA235) in the coating liquid L1 for the low refractive index layer, polyvinyl alcohol Z-410 (degree of polymerization 2300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and polyvinyl alcohol (R-1130) (Mixture ratio 1700, saponification degree 98.5 mol%, manufactured by Kuraray Co., Ltd.) and PVA235, polymerization degree 3500, manufactured by Kuraray Co., Ltd.) The coating liquid L7 for low refractive index layers was prepared in the same manner as the coating liquid L1 for low refractive index layers except that was used.

(Preparation of coating liquid H11 for high refractive index layer)
Instead of a 5 mass% aqueous solution of polyvinyl alcohol (JP-33) in the coating liquid H1 for the high refractive index layer, polyvinyl alcohol (PVA103 (polymerization degree 300, saponification degree 98.5 mol%, manufactured by Kuraray Co., Ltd.), PVA117, polymerization And a degree of saponification of 98.5 mol%, manufactured by Kuraray Co., Ltd.) and Z-410 (polymerization degree of 2300, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 30:60:10 (solid content mass ratio)) A high-refractive-index layer coating solution H11 was prepared in the same manner as the high-refractive-index layer coating solution H1 except that a 5% by mass aqueous solution was used.

(Preparation of sample 18)
In Example 1, the high refractive index layer coating liquid H11 was used instead of the high refractive index layer coating liquid H1, and the low refractive index layer coating liquid L7 was used instead of the low refractive index layer coating liquid L1. Sample 18 was made in the same manner as Example 1 except for the above.

[Example 19]
(Preparation of coating liquid L8 for low refractive index layer)
Instead of the 5 mass% aqueous solution of polyvinyl alcohol (PVA235) in the coating liquid L1 for the low refractive index layer, polyvinyl alcohol (PVA235, polymerization degree 3500, manufactured by Kuraray Co., Ltd.) and polyvinyl alcohol (PVA205 (polymerization degree 500, manufactured by Kuraray Co., Ltd.) A low refractive index layer coating liquid L8 was prepared in the same manner as the low refractive index layer coating liquid L1 except that a 5% by weight aqueous solution of 25:75 (solid content mass ratio) was used.

(Preparation of Sample 19)
In Example 4, Sample 19 was produced in the same manner as in Example 4 except that the low refractive index layer coating liquid L8 was used instead of the low refractive index layer coating liquid L1.

[Comparative Example 1]
In Example 5, instead of polyvinyl alcohol (PVA224, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (JP-45, degree of polymerization: 4500, degree of saponification: 88 mol%, manufactured by Nippon Vineyard Poval Co., Ltd.) was used. A sample 20 was prepared in the same manner as in Example 5 except that the high refractive index layer coating solution H12 was prepared.

The compositions of the samples of Examples 1 to 19 and Comparative Example 1 (infrared shielding film samples 1 to 20) are summarized in Tables 1 and 2 below.

<Evaluation of infrared shielding film>
The following performance evaluation was performed about each infrared shielding film sample produced above. The results are shown in Table 3 below.

(Measurement of single film refractive index of each layer)
Samples are prepared by coating the target layers (high refractive index layer and low refractive index layer) whose refractive index is measured on the base material as single layers, and according to the following method, each of the high refractive index layer and the low refractive index layer The refractive index of was determined.

Using a U-4000 model (manufactured by Hitachi, Ltd.) as a spectrophotometer, the back surface on the measurement side of each sample is roughened, and then light absorption is performed with a black spray to reflect light on the back surface. The refractive index was obtained from the measurement result of the reflectance in the visible light region (400 nm to 700 nm) under the condition of regular reflection at 5 degrees.

As a result of measuring the refractive index of each layer according to the above method, it was confirmed that the refractive index difference between the high refractive index layer and the low refractive index layer of Samples 1 to 20 was 0.3 or more.

(Measurement of visible light transmittance and infrared transmittance)
Using a spectrophotometer (integral sphere, manufactured by Hitachi, Ltd., U-4000 type), visible light transmittance (400 nm to 700 nm) and infrared transmittance (800 nm) in the region of 300 nm to 2000 nm of each infrared shielding film sample. ˜1300 nm) was measured.

(Interlayer adhesion)
Each infrared shielding film sample prepared above was treated (leaved) at 55 ° C. for 7 days, and then evaluated for adhesion. The adhesion was evaluated according to the following criteria by the cross-cut (cross-cut) method in JIS K5600-5-6 (1999).

(Applicability)
The infrared shielding film sample produced above was observed visually, and the presence or absence of streaks and unevenness was evaluated according to the following criteria. The film was cut into 210 mm × 297 mm and evaluated.

(Moisture resistance)
Each infrared shielding film sample produced above is held in an environment of 60 ° C. and 90% humidity for 3 days, and then immediately held in an environment of −20 ° C. and 10% humidity) for 12 hours in the environment as one cycle. After 5 cycles, the change in haze before and after charging was measured for 12 hours in a room temperature (25 ° C.) environment, and the haze difference before and after charging was evaluated.

From Table 3 above, it can be seen that the infrared blocking film samples 1 to 19 of the present invention are superior in interlayer adhesion compared to the infrared blocking film sample 20 of Comparative Example 1.

[Example 20]
[Production of Infrared Shields 101 to 119]
As shown below, a hard coat layer was provided on the infrared shielding films of Samples 1 to 19 produced in Examples 1 to 19, and an acrylic adhesive layer was provided on the side opposite to the hard coat layer. Infrared shields 101 to 119 were prepared by bonding them onto glass plates having a thickness of 5 mm and 20 cm × 20 cm, respectively.

(Hard coat layer)
Hard coat layer coating solution 73 parts pentaerythritol tri / tetraacrylate (NK ester A-TMM-3, Shin-Nakamura Chemical Co., Ltd.), 5 parts Irgacure 184 (Ciba Japan Co., Ltd.), 1 Part of a silicone surfactant (KF-351A, manufactured by Shin-Etsu Chemical Co., Ltd.), 10 parts of propylene glycol monomethyl ether, 70 parts of methyl acetate, and 70 parts of methyl ethyl ketone were obtained. The mixed solution was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution.

Application | coating and drying The said coating liquid for hard-coat layers was apply | coated on said resin adhesive layer using the micro gravure coater, and it dried at the constant rate drying area temperature of 50 degreeC and the decreasing rate drying area temperature of 70 degreeC. At this time, the coating amount was adjusted so that the film thickness during drying was 3 μm.

Ultraviolet irradiation While purging with nitrogen, the coating film obtained using an ultraviolet lamp was cured. The curing conditions were oxygen concentration: 1.0% by volume or less, illuminance: 100 mW / cm ² , and irradiation amount: 0.2 J / cm ² .

<Evaluation of infrared shielding material>
The infrared shielding bodies 101 to 119 of the present invention produced as described above were confirmed to have excellent infrared shielding properties.

Furthermore, this application is based on Japanese Patent Application No. 2012-246462 filed on November 8, 2012, the disclosure content of which is referenced and incorporated as a whole.

Claims

An optical laminated film having a substrate and a reflective layer that reflects at least light,
The reflective layer has a plurality of laminated refractive index layers,
At least one of the refractive index layers has a refractive index different from at least one of the adjacent refractive index layers;
The refractive index layer contains a polyvinyl alcohol-based resin,
The average degree of polymerization of the polyvinyl alcohol resin contained in one refractive index layer is different from the average degree of polymerization of the polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer, or the one refractive index. An optical laminated film in which the polymerization degree of the maximum amount of polyvinyl alcohol resin contained in the layer is different from the polymerization degree of the maximum amount of polyvinyl alcohol resin contained in at least one of the refractive index layers adjacent to the refractive index layer.
The optical laminated film according to claim 1, wherein at least one of the refractive index layers further contains metal oxide particles.
The optical laminated film according to claim 1 or 2, wherein the degree of polymerization of the polyvinyl alcohol-based resin contained in the one refractive index layer is 5000 or less.
The optical laminated film according to any one of claims 1 to 3, wherein an average polymerization degree or a difference in polymerization degree between the one refractive index layer and at least one of the adjacent refractive index layers is 300 or more. .
In the refractive index layer, a high refractive index layer and a low refractive index layer are alternately laminated, and a thickness of at least one of the plurality of high refractive index layers is different, or a plurality of the low refractive indexes is formed. The optical laminated film according to any one of claims 1 to 4, wherein at least one of the layers has a different thickness.
The refractive index layer constituting the reflective layer, wherein the lowermost layer located on the most substrate side of the reflective layer is 9 times or more thicker than the refractive index layer other than the lowermost layer. The optical laminated film according to any one of the above.
The optical laminated film according to any one of claims 1 to 6, wherein at least one of the refractive index layers contains a modified polyvinyl alcohol.
The refractive index layer has a refractive index layer containing titanium oxide as metal oxide particles, and the refractive index layer containing titanium oxide does not contain gelatin or thickening polysaccharide. The optical laminated film according to Item.
The optical laminated film according to any one of claims 1 to 8, which is an infrared shielding film.
An infrared shielding body using the optical laminated film according to claim 9.
A method for producing an optical reflective film according to any one of claims 1 to 9,
A process of forming an optical reflective film including a high refractive index layer and a low refractive index layer by simultaneously applying a high refractive index layer coating liquid and a low refractive index layer coating liquid on a substrate and then drying. A method for producing an optical reflective film.