WO2014069506A1 - Optically reflective film, infrared-shielding film, and infrared shield - Google Patents

Abstract

The purpose of the present invention is to provide: an optically reflective film having favorable coating properties and low haze properties (excellent film-surface uniformity); an infrared-shielding film; and an infrared shield equipped with the infrared-shielding film. This optically reflective film is an optically reflective film having a substrate and a reflective layer which at least reflects infrared light, wherein: the reflective layer has a plurality of layered refractive-index layers; one or more of the refractive-index layers have a different refractive index than that of the refractive-index layers adjacent thereto; one or more of the refractive-index layers which configure the reflective layer contain metal-oxide fine particles, a water-soluble zirconium compound, carboxylic acid, and a polyvinyl-alcohol-based resin; and the mixing ratio of the water-soluble zirconium compound and the carboxylic acid therein is 2-16:1 (water-soluble zirconium compound (solid content converted to zirconia): solid content of carboxylic acid (mass ratio)).

Description

Optical reflection film, infrared shielding film, and infrared shielding body

The present invention relates to an optical reflection 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.

As an infrared shielding film, a laminated film in which a high refractive index layer and a low refractive index layer are alternately laminated using a wet coating method has been proposed. However, when a high refractive index layer and a low refractive index layer are formed by a wet coating method, there is a problem that coating unevenness easily occurs and haze is high.

Among the above problems, a method for adding a metal oxide and a specific inorganic polymer to a high refractive index layer or a low refractive index layer has been reported in order to solve the problem of an increase in haze (see, for example, Patent Document 1). . The near-infrared reflective film obtained by the method disclosed in Patent Document 1 has excellent durability that does not change color even when exposed to light for a long period of time and does not increase haze.

JP 2012-27288 A

However, even with the method disclosed in Patent Document 1, sufficient haze reduction is not achieved, and further reduction of haze is required. Further, in the method disclosed in Patent Document 1, coating unevenness is likely to occur when the high refractive index layer and the low refractive index layer are formed, and the coating property cannot be said to be sufficient.

Accordingly, the present invention has been made in view of the above problems, and provides an optical reflecting film having good coatability and low haze, an infrared shielding film, and an infrared shielding body provided with the infrared shielding film. The purpose is to do.

The present inventor has intensively studied in view of the above problems. As a result, metal oxide fine particles, water-soluble zirconium compound, carboxylic acid and polyvinyl alcohol resin are used in at least one of the refractive index layers, and the mixing ratio of the water-soluble zirconium compound and carboxylic acid in that case is within a specific range. As a result, the present inventors have found that the above problem can be solved, and have completed the present invention.

That is, in order to achieve at least one of the above objects, an optical reflective film reflecting one aspect of the present invention is an optical reflective film having a base material and a reflective layer that reflects at least infrared light. 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 that of an adjacent refractive index layer, and the refractive index constituting the reflective layer Among the layers, at least one of the refractive index layers contains metal oxide fine particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol-based resin, and a mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble). Zirconium compound (solid content in terms of zirconia): carboxylic acid solid content (mass ratio)) is 2 to 16: 1.

In order to achieve at least one of the above objects, an infrared shielding film reflecting another aspect of the present invention is an infrared shielding film having a base material and a reflective layer that reflects at least infrared light. 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 that of an adjacent refractive index layer, and the refractive layer constituting the reflective layer. Among the refractive index layers, at least one of the refractive index layers contains metal oxide fine particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol-based resin, and a mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble). Zirconium compound (solid content in terms of zirconia): carboxylic acid solid content (mass ratio)) is 2 to 16: 1.

The present invention is an optical reflective film having a base material and a reflective layer that reflects at least infrared light, wherein the reflective layer has a plurality of laminated refractive index layers, At least one has a refractive index different from that of the adjacent refractive index layer, and among the refractive index layers constituting the reflective layer, at least one of the refractive index layers is composed of metal oxide fine particles, water-soluble zirconium compound, carbon An acid and a polyvinyl alcohol-based resin, and a mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble zirconium compound (solid content in terms of zirconia): carboxylic acid solid content (mass ratio)) is 2 to An optical reflective film is provided that is 16: 1. The present invention is characterized by adding a water-soluble zirconium compound and a carboxylic acid at a specific mixing ratio to at least one of the refractive index layers. The optical reflective film having such a configuration has good coatability and lowers haze. 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, by mixing a water-soluble zirconium compound in a liquid for forming a refractive index layer mainly composed of metal oxide fine particles and polyvinyl alcohol resin, the hydroxyl groups of the metal oxide fine particles and the hydroxyl groups of the polyvinyl alcohol resin are cross-linked. Therefore, it is considered that the film surface is leveled, coating unevenness is reduced, and haze is reduced. On the other hand, if the water-soluble zirconium compound is simply mixed with the liquid containing the metal oxide fine particles and the polyvinyl alcohol-based resin, the crosslinking reaction continues to proceed, conversely, the stability of the liquid is lowered and the haze reduction effect is reduced. The problem of hindering arises. For this reason, in this invention, a liquid is stabilized by adding carboxylic acid which acts as a chelating agent of a water-soluble zirconium compound so that it may become a specific mixing ratio, and a crosslinking reaction is preferentially performed when drying. Therefore, by adding the water-soluble zirconium compound and the carboxylic acid, the coatability is improved, and the haze of the obtained optical reflection film can be reduced. The above effect is particularly effectively exhibited when the low refractive index layer contains metal oxide fine particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol resin. Therefore, according to the present invention, an optical reflection film having low haze (excellent film surface uniformity), an infrared shielding film, and an infrared shielding body provided with the infrared shielding film can be provided. Moreover, the optical reflective film and infrared shielding film of this invention have the favorable applicability | paintability at the time of the manufacture, and can suppress and prevent generation | occurrence | production of a coating nonuniformity.

The optical reflection film and infrared shielding film of the present invention exhibit high visible light transmittance and excellent infrared shielding properties. Furthermore, the optical reflection film and 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 constituent elements of the optical reflection film of the present invention and the modes for carrying out the present invention 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 reflection film]
The optical reflective 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 laminated refractive index layers, and at least one of the refractive index layers has a refractive index different from that of the adjacent refractive index layer. 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 reflective film is focused on two adjacent refractive index layers. All forms other than those having a refractive index are included. And the reflection of visible light and near-infrared light is controlled by controlling the refractive index and film thickness of each layer. That is, the refractive index of each layer, the film thickness of each layer, and the way of laminating each layer can increase the reflectance in a specific wavelength region, and by changing the specific wavelength region that increases the reflectance, a visible light reflecting film Or a near-infrared reflective film. That is, if the specific wavelength region for increasing the reflectance is set to the visible light region, the visible light reflecting film is obtained, and if the specific wavelength region is set to the near infrared region, the near infrared reflecting film is obtained. Moreover, if the specific wavelength area | region which raises a reflectance is set to an ultraviolet light area | region, it will become an ultraviolet reflective film. When the optical reflective film of the present invention is used for a heat shield film, a (near) infrared reflective (shield) film may be used. That is, according to a preferred aspect of the present invention, there is provided 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. And at least one of the refractive index layers has a refractive index different from that of an adjacent refractive index layer, and among the refractive index layers constituting the reflective layer, at least one of the refractive index layers is a metal oxide fine particle. , A water-soluble zirconium compound, a carboxylic acid and a polyvinyl alcohol resin, and a mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble zirconium compound (solid content in terms of zirconia)): carboxylic acid solid content (mass An infrared shielding film with a ratio)) of 2 to 16: 1 is provided. Hereinafter, these may be referred to as “optical reflection film” or “infrared shielding film”.

In the present invention, the optical reflective 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).

In general, in an optical reflecting 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 units composed of the low refractive index layer and the high refractive index layer, the refractive index difference between the adjacent low refractive index layer and the high refractive index layer is preferably 0.1 or more. More preferably, it is 0.3 or more, More preferably, it is 0.35 or more, Especially preferably, it is 0.4 or more. When the optical reflective film has a plurality of high refractive index layer and low refractive index layer units, the refractive index difference between the high refractive index layer and the low refractive index layer in all the units may be within the preferred range. preferable. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used. In the optical reflective 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 reflection film of this embodiment, the transmittance in the visible light region shown in JIS R3106 (1998) is preferably 50% or more, preferably 75% or more, more preferably 85% or more. In addition, it is preferable that the region having a wavelength of 900 nm to 1400 nm has a region with a reflectance exceeding 50%.

The optical reflective film of the present embodiment may be one having a configuration including at least one unit composed of a high refractive index layer and a low refractive index layer on a substrate. 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 optical reflective 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 high refractive index layers or low refractive index layers. However, from the viewpoint of adhesion to the substrate, it is preferable that the low refractive index layer is located closest to the substrate of the reflective layer. The optical reflective film of the present invention preferably has 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.

The total thickness of the optical reflective 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 layer of the low refractive index layer other than the layer located closest to the substrate side 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.

The optical reflective 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, abrasion resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorbing layer, infrared absorbing layer, printed layer, fluorescent light emitting layer, hologram layer , Peeling layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer) other than the high refractive index layer and low refractive index layer of the present invention, a colored layer (visible light absorbing layer), and laminated glass One or more functional layers such as an intermediate film layer may be included.

[Water-soluble zirconium compound and carboxylic acid]
In the optical reflective film of the present invention, at least one of the refractive index layers constituting the reflective layer contains a water-soluble zirconium compound and a carboxylic acid in addition to the metal oxide fine particles and the polyvinyl alcohol resin. It is characterized by that. Here, the water-soluble zirconium compound and the carboxylic acid may be contained in any refractive index layer, but are preferably contained in the low refractive index layer. That is, the reflective layer has at least one laminate in which low refractive index layers and high refractive index layers having different refractive indexes are alternately laminated, and the low refractive index layer includes metal oxide fine particles, water-soluble It is preferable to contain a zirconium compound, a carboxylic acid, and a polyvinyl alcohol resin. When the low refractive index layer has the above configuration, the film surface can be leveled to reduce coating unevenness (improve coatability) and further reduce haze.

Here, the water-soluble zirconium compound is not particularly limited. Specifically, zirconium oxychloride (ZrOCl ₂ ), zirconium sulfate (ZrOSO ₄ ), zirconium oxynitrate (ZrO (NO ₃ ) ₂ ), zirconium ammonium carbonate ((NH ₄ ) ₂ Zr (OH) ₂ (CO ₃ ) ₂ ), potassium zirconium carbonate (K ₂ Zr (OH) ₂ (CO ₃ ) ₂ ), zirconium acetate (ZrO (C ₂ H ₃ O ₂ ) ₂ ), zirconium phosphate (Zr (O ₃ POH) ₂ ), etc. Can be mentioned. Among these, from the viewpoint of liquid stability between the metal oxide fine particles and the polyvinyl alcohol resin, zirconium acetate, ammonium zirconium carbonate, zirconium zirconium carbonate, and zirconium oxynitrate are preferable, and ammonium zirconium carbonate and potassium zirconium carbonate are more preferable.

The content of the water-soluble zirconium compound (solid content in terms of zirconia (ZrO ₂ )) is not particularly limited, but film surface leveling (reduction of coating unevenness) by crosslinking of hydroxyl groups of metal oxide fine particles and hydroxyl groups of polyvinyl alcohol resin ) And a decrease in haze, the amount is preferably 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass of the metal oxide fine particles. With such an amount, the cross-linking reaction between the hydroxyl group of the metal oxide fine particles and the hydroxyl group of the polyvinyl alcohol resin proceeds to level the film surface, reduce coating unevenness, and reduce haze.

The carboxylic acid is not particularly limited as long as it can be used as a chelating agent for a water-soluble zirconium compound, and is an organic acid (formula: R—COOH) having at least one carboxyl group (—COOH). Specifically, monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, caproic acid, lauric acid, stearic acid, salicylic acid, lactic acid, benzoic acid; oxalic acid, malonic acid, tartaric acid, malic acid, phthalic acid, isophthalic acid Examples thereof include polyvalent carboxylic acids having two or more carboxyl groups such as acid, maleic acid, terephthalic acid, citric acid, adipic acid, sebacic acid, succinic acid and trimellitic acid. Among these, in view of improvement in coating property due to the action of the water-soluble zirconium compound as a chelating agent and reduction in haze, it is preferably a polyvalent carboxylic acid, and preferably has at least two carboxyl groups (—COOH) and at least 1 A hydroxy acid having two hydroxyl groups (—OH) is more preferable, and malic acid, citric acid, and tartaric acid are particularly preferable.

The content of the carboxylic acid is not particularly limited, but considering the improvement in applicability and the reduction in haze due to the action of the water-soluble zirconium compound as a chelating agent, it is 0.005 with respect to 100 parts by mass of the metal oxide fine particles. The amount is preferably 0.5 to 0.5 parts by mass, and more preferably 0.01 to 0.2 parts by mass. With such an amount, the carboxylic acid can effectively act as a chelating agent for the water-soluble zirconium compound, stabilizes the liquid for forming the refractive index layer, and applies a crosslinking reaction preferentially when drying. Can improve the haze.

In the present invention, when the refractive index layer contains metal oxide fine particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol resin, the mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble zirconium compound (as zirconia conversion) Solid content): carboxylic acid solid content (mass ratio) is 2 to 16: 1. Here, the amount of the water-soluble zirconium compound is a solid content in terms of zirconia (ZrO ₂ ), the amount of carboxylic acid is the carboxylic acid solid content, and the above mixing ratio is a mass ratio thereof. With such a mixing ratio, the water-soluble zirconium compound appropriately proceeds with the crosslinking reaction between the hydroxyl groups of the metal oxide fine particles and the hydroxyl groups of the polyvinyl alcohol resin to level the film surface and reduce coating unevenness. , Haze can be reduced. On the other hand, when the mixing ratio (mass ratio) of the water-soluble zirconium compound is less than twice that of the carboxylic acid, the effect of improving the coating property cannot be achieved. Further, when the mixing ratio (mass ratio) of the water-soluble zirconium compound exceeds 16 times that of the carboxylic acid, there is a problem that the coating liquid becomes unstable (liquid stability is reduced). Preferably, the mixing ratio of the water-soluble zirconium compound and carboxylic acid is 3 to 15: 1, more preferably 4 to 14: 1.

Next, the basic configuration outline of the high refractive index layer and the low refractive index layer other than the water-soluble zirconium compound and carboxylic acid in the optical reflection film of the present invention will be described.

[Low refractive index layer]
In the present invention, the low refractive index layer preferably contains the first metal oxide particles or polyvinyl alcohol-based resin, and more preferably contains the first metal oxide particles and polyvinyl alcohol-based resin. In the present invention, the low refractive index layer may further contain a protective agent, a curing agent, an emulsion resin, and various other additives.

[First metal oxide particles]
The low refractive index layer of the present invention preferably contains 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.

[Polyvinyl alcohol resin]
In the optical reflective film according to the present invention, the low refractive index layer preferably contains a polyvinyl alcohol-based resin. Here, the polyvinyl alcohol-based resin acts as a binder resin. 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 low refractive index layer of the present invention, the use of a polyvinyl alcohol resin is preferable because the liquid stability of the coating solution for the low refractive index layer is excellent, and as a result, the coating property is excellent. In this specification, “water-soluble polyvinyl alcohol-based resin (water-soluble binder resin)” means a temperature at which the water-soluble polymer compound is most dissolved and is dissolved in water having a concentration of 0.5% by mass. , A water-soluble polymer compound in which the mass of insoluble matter that is filtered off when filtered through a G2 glass filter (maximum pores 40 to 50 μm) is within 50 mass% of the added water-soluble polymer compound. When there are a plurality of low refractive index layers, the polyvinyl alcohol resins used in each low refractive index layer may be the same or different.

The polyvinyl alcohol resin preferably used in the present invention includes, in addition to a normal polyvinyl alcohol resin (unmodified polyvinyl alcohol) obtained by hydrolyzing polyvinyl acetate, cation-modified polyvinyl alcohol (cation-modified polyvinyl alcohol). Alcohol), anion-modified polyvinyl alcohol having an anionic group, and non-modified polyvinyl alcohol having a nonionic group are also included.

The polyvinyl alcohol resin (unmodified polyvinyl alcohol) obtained by hydrolysis of vinyl acetate preferably has an average degree of polymerization of 500 or more, more preferably 1,000 or more, and 1,500 or more. Even more preferred is 2,000 or more. The upper limit of the average degree of polymerization of the polyvinyl alcohol resin (unmodified polyvinyl alcohol) is not particularly limited, but is preferably 6,000 or less, and more preferably 5,000 or less. This is because the strength of the coating film is good when it is 1,500 or more, and the coating solution is stable when it is 6,000 or less. Furthermore, when the average degree of polymerization is 2000 or more, there is no crack in the coating film, and the haze is good, which is preferable. The degree of saponification is preferably 70 to 100 mol%, particularly preferably 80 to 99.5 mol%. 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.) 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 in 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.

The polyvinyl alcohol-based resin may be used alone or in combination of two or more such as average polymerization degree and different types of modification.

In the present invention, the polyvinyl alcohol-based resin is preferably contained in the range of 5 to 50% by mass, more preferably 10 to 40% by mass, with respect to 100% by mass of the total solid content of the low refractive index layer. More preferred is 35% by mass. If the amount of the polyvinyl alcohol-based resin is 5% by mass or more, the film surface is prevented from being disturbed during drying after the application of the refractive index layer, and the tendency to increase transparency is increased. On the other hand, if the content is 50% by mass or less, the relative content of the metal oxide becomes appropriate, and it becomes easy to increase the difference in refractive index between the high refractive index layer and the low refractive index layer.

[Silanol-modified polyvinyl alcohol]
In the present invention, the low refractive index layer may contain silanol-modified polyvinyl alcohol in addition to the polyvinyl alcohol-based resin. Here, there is no restriction | limiting in particular as silanol modified polyvinyl alcohol, The thing synthesize | combined by the well-known method may be sufficient, and a commercial item may be sufficient. The average degree of polymerization of the silanol-modified polyvinyl alcohol is usually 300 to 2,500, preferably 500 to 1,700. When the average degree of polymerization is 300 or more, the strength of the coating layer is high, and when it is 2,500 or less, the viscosity of the coating solution does not become too high, and the process suitability is preferable. 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. Among these, silanol-modified polyvinyl alcohol having a saponification degree of preferably 95 mol% or more, more preferably 95.0 to 99.5 mol% is preferable from the viewpoint of scratch resistance and gloss marks.

The content of the silanol-modified polyvinyl alcohol is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, with respect to 100% by mass of the total solid content of the low refractive index layer. It is particularly preferable that the content is% by mass. If it is 3% by mass or more, the setability is improved, so that the film is hardly disturbed and the haze is good, and if it is 40% by mass or less, the stability of the liquid is good.

[Protective agent]
In one embodiment of the present invention, the low refractive index layer preferably contains at least two water-soluble resins. At this time, it is preferable that at least one type covers (also referred to as protection) the first metal oxide particles, and the other type functions as a binder resin. Below, the water-soluble resin which coat | covers (protects) the 1st metal oxide particle is demonstrated. The water-soluble resin has a role for facilitating dispersion of the metal oxide particles in a solvent, and is hereinafter referred to as a “protecting agent”.

The protective agent is preferably a water-soluble resin having an average degree of polymerization of preferably 100 to 700, more preferably 200 to 500, from the viewpoint of stabilizing the metal oxide fine particles. Further, polyvinyl alcohol is preferable from the viewpoint of adsorptivity, but modified polyvinyl alcohol is more preferable from the viewpoint of transparency and stabilization. Furthermore, when the saponification degree of polyvinyl alcohol is preferably 95% mol or more, more preferably 98 to 99.5 mol%, the adsorptivity to particles is strong and preferable. About polyvinyl alcohol, since it described with the polyvinyl alcohol-type resin, it abbreviate | omits.

In the present invention, the protective agent is preferably contained in the range of 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, with respect to 100% by mass of the metal oxide particles. More preferred is mass%. Including the protective agent in the above range is preferable because the liquid stability of the coating solution for the low refractive index layer is excellent and the coating property is stabilized.

[Curing agent]
The low refractive index layer of the present invention may contain a curing agent. In the case where a polyvinyl alcohol resin is used as the binder resin, the effect can be exhibited particularly.

In the present invention, the curing agent that can be used with the polyvinyl alcohol resin is not particularly limited as long as it causes a curing reaction with polyvinyl alcohol, but is selected from the group consisting of boric acid, borate, and borax. It is preferred that Known compounds other than boric acid, borate, and borax can be used, and generally compounds having a group capable of reacting with polyvinyl alcohol or compounds that promote the reaction between different groups possessed by polyvinyl alcohol These 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 as 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, 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 preferably 1 to 600 mg per gram of polyvinyl alcohol resin (or the total amount of polyvinyl alcohol resin and silanol modified polyvinyl alcohol when silanol modified polyvinyl alcohol is also used). ˜500 mg is more preferred.

[Other additives]
In addition, the low refractive index layer includes, for example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, Discoloration inhibitors, anions, cations, and nonions described in JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091 and JP-A-3-13376, etc. Or various amphoteric surfactants described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771 and JP-A-4-219266. Fluorescent brighteners, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents, diethyleneglycol A lubricant such as Le, preservatives, antistatic agents, may contain various known additives such as a matting agent.

[High refractive index layer]
In the present invention, the high refractive index layer preferably contains the second metal oxide particles or the polyvinyl alcohol resin, and more preferably contains the second metal oxide particles and the polyvinyl alcohol resin. In the present invention, the high refractive index layer may further contain a protective agent, a curing agent, an emulsion resin, and various other additives.

[Second metal oxide particles]
The high refractive index layer of the present invention preferably contains second metal oxide particles. The second metal oxide particles that can be included in the high refractive index layer are preferably metal oxide particles different from the 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, zirconium oxide, 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 content of the metal oxide particles in the high refractive index layer is preferably 15 to 85% by mass, and preferably 20 to 80% by mass with respect to 100% by mass of the total solid content of the high refractive index layer. More preferred is 30 to 75% by mass. By setting it as the said range, it can be set as the favorable infrared shielding property.

As the titanium oxide particles of the present invention, those obtained by modifying the surface of an aqueous titanium oxide sol so as to be dispersible in an organic solvent or the like are preferably used.

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 WO 2007/039953 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 so 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 metallic tin, while maintaining a molar ratio of H ₂ O ₂ / Sn of 2 to 3, simultaneously or alternately, such as a titanium salt (for example, titanium tetrachloride), etc. 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 100 parts by mass in terms of metal oxide TiO ₂ , and the obtained composite aqueous sol containing silicon dioxide is 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); Including) Titanium oxide hydrosol obtained by peptizing titanium hydroxide, organoalkoxysilane (R ¹ nSiX _4-n ) as a stabilizer or a compound selected from hydrogen peroxide and aliphatic or aromatic hydroxycarboxylic acid 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.

[Polyvinyl alcohol resin]
In the optical reflective film according to the present invention, the high refractive index layer preferably contains a polyvinyl alcohol-based resin. Here, the polyvinyl alcohol-based resin acts as a binder resin. 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 high refractive index layer of the present invention, the use of a polyvinyl alcohol-based resin is preferable because the liquid stability of the coating solution for the high refractive index layer is excellent, and as a result, the coating property is excellent. When there are a plurality of high refractive index layers, the polyvinyl alcohol resins used in each high refractive index layer may be the same or different. Further, the polyvinyl alcohol resins used in the high refractive index layer and the low refractive index layer may be the same or different.

The polyvinyl alcohol resin used in the high refractive index layer is omitted here because the same resin as the low refractive index layer can be applied.

The content of the polyvinyl alcohol resin in the high refractive index layer is preferably 3 to 70% by mass, more preferably 5 to 60% by mass, and still more preferably 10% with respect to 100% by mass of the total solid content of the high refractive index layer. -50% by mass, particularly preferably 15-45% by mass.

[Protective agent]
In one embodiment of the present invention, the high refractive index layer preferably contains at least two water-soluble resins (polyvinyl alcohol resin). At this time, it is preferable that at least one type covers (also referred to as protection) the second metal oxide particles, and the other type functions as a binder resin. The water-soluble resin that coats the second metal oxide particles is referred to as a “protecting agent”.

As the protective agent, the same ones as described in the low refractive index layer can be used.

In the present invention, the protective agent is preferably contained in the range of 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, with respect to 100% by mass of the metal oxide particles. More preferred is mass%. Including the protective agent in the above range is preferable because the liquid stability of the coating solution for the high refractive index layer is excellent and the coating property is stable.

[Curing agent]
The high refractive index layer of the present invention may contain a curing agent. This is because, when a polyvinyl alcohol-based resin is used, the curing agent can react with polyvinyl alcohol to form a hydrogen bond network. In addition, about the hardening | curing agent used with a high refractive index layer, since the thing similar to a low refractive index layer may be applied, it abbreviate | omits here.

The total amount of the curing agent used in the high refractive index layer is preferably 1 to 600 mg, more preferably 100 to 600 mg, per 1 g of polyvinyl alcohol resin.

[Base material]
The substrate used for the optical reflection 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%). It is 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. Yes, 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.

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).

[Method for producing optical reflection film]
There is no restriction | limiting in particular about the manufacturing method of the optical reflection 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 optical reflective film of the present invention, a unit composed of a high refractive index layer and a low refractive index layer is laminated on a substrate, for example, a coating liquid for a high refractive index layer and a low refractive index. A layered coating solution is alternately applied and dried to form a laminate. That is, a coating liquid for a low refractive index layer containing a desired component (for example, metal oxide particles, polyvinyl alcohol resin, water-soluble zirconium compound, carboxylic acid and solvent), and a desired component (for example, metal oxide particles) A coating solution for a high refractive index layer including a polyvinyl alcohol resin and a solvent), and a step of drying the substrate coated with the coating solution. Obtained by the manufacturing method. In the above, the water-soluble zirconium compound and the carboxylic acid are used only for the coating solution for the low refractive index layer, but the high refractive index is used instead of or in addition to the coating solution for the low refractive index layer. It goes without saying that a water-soluble zirconium compound and a carboxylic acid may also be added to the coating solution for the rate layer.

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 and forming an optical reflective 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 of forming a high refractive index layer by applying a coating solution for a high refractive index layer and drying to form an optical reflective film; (3) a coating solution for a high refractive index layer and a low refractive index layer on a substrate; A method of forming an optical reflective film including a high refractive index layer and a low refractive index layer by alternately applying successive coating layers for coating and then drying; (4) coating for a high refractive index layer on a substrate; A liquid and a coating solution for a low refractive index layer are simultaneously applied and dried to form an optical reflective film including a high refractive index layer and a low refractive index layer; Etc., and the like. Among these, the method (4), which is a simpler manufacturing process, is preferable.

(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. In the following, a preferred embodiment in which the water-soluble zirconium compound and carboxylic acid are used only in the coating solution for the low refractive index layer will be described. However, the present invention is not limited to the above embodiment, and instead of the coating solution for the low refractive index layer. Alternatively, in addition to the coating solution for the low refractive index layer, a water-soluble zirconium compound and a carboxylic acid may be added to the coating solution for the high refractive index layer.

The method for preparing the coating solution for the low refractive index layer is not particularly limited. For example, metal oxide particles, polyvinyl alcohol resin, water-soluble zirconium compound, carboxylic acid and solvent, and other additives added as necessary. And stirring and mixing. The method for preparing the coating solution for the high refractive index layer is not particularly limited. For example, a method in which metal oxide particles, polyvinyl alcohol resin and a solvent, and other additives added as necessary are added and stirred and mixed. Is 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. Moreover, the addition amount of each said component is although it does not restrict | limit in particular, It is preferable to add each component so that it may become each above content and mixing ratio.

In addition, it is preferable to use what was separately prepared in the state of the dispersion liquid before preparing a coating liquid for the 2nd metal oxide particle. 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. 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 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 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 is adjusted by adjusting the concentration of polyvinyl alcohol resin and metal oxide particles, and adding other components such as gelatin, pectin, agar, carrageenan, gellan gum and other known gelling agents. It can be adjusted by doing.

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 the surface of the 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.

It is preferable that the adhesive layer or the adhesive layer that bonds the infrared shielding film and the substrate is disposed on the sunlight (heat ray) incident surface side of the infrared shielding film. 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.

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.

Insulation performance and solar heat shielding performance of an infrared shielding film or infrared shield are generally JIS R 3209 (1998) (multi-layer glass), JIS R 3106 (1998) (transmittance / reflectance of sheet glass, Emissivity and solar heat gain test method), 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) The solar transmittance, solar reflectance, solar absorption rate, and corrected emissivity are calculated according to JIS R 3106 (1998) by calculating the solar transmittance, solar reflectance, solar absorption rate, and vertical emissivity. 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 multilayer 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 determined 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 calculating 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 sodium hydroxide aqueous solution (concentration: 10 mol / L) was added to 10 L (liter) of an aqueous suspension (TiO ₂ concentration: 100 g / L) in which titanium 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% by mass of 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 11 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) 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 11 layers were applied alternately so that the film thickness during drying was 150 nm for each low refractive index layer and 130 nm for each high refractive index layer.

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 setting, hot air of 80 ° C. was blown and dried to prepare a multilayer coating product consisting of 11 layers.

The 11-layer multilayer coating was further applied to the back surface of the 11-layer multilayer coating product to prepare Sample 1 consisting of 22 layers on both sides.

[Example 2]
(Preparation of coating liquid L2 for low refractive index layer)
In Example 1 (Preparation of coating solution L1 for low refractive index layer), except that the amount of 5.0 mass% acetic acid aqueous solution used was changed from 5 parts to 1.67 parts, in the same manner as in Example 1, A coating liquid L2 for low refractive index layer was prepared.

(Preparation of sample 2)
In Example 1, Sample 2 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L2 was used instead of the low refractive index layer coating liquid L1.

[Example 3]
(Preparation of coating liquid L3 for low refractive index layer)
In Example 1 (Preparation of coating solution L1 for low refractive index layer), Example 1 was used except that 4 parts of 5.0% by mass lactic acid aqueous solution was used instead of 5 parts by mass of 5.0% by mass acetic acid aqueous solution. In the same manner as described above, a coating solution L3 for a low refractive index layer was prepared.

(Preparation of sample 3)
In Example 1, Sample 3 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L3 was used instead of the low refractive index layer coating liquid L1.

[Example 4]
(Preparation of coating liquid L4 for low refractive index layer)
In Example 3 (Preparation of coating solution L3 for low refractive index layer), except that the amount of 5.0% by mass lactic acid aqueous solution used was changed from 4 parts to 1.43 parts, in the same manner as in Example 3, A coating solution L4 for a low refractive index layer was prepared.

(Preparation of sample 4)
In Example 3, Sample 4 was produced in the same manner as in Example 3, except that the low refractive index layer coating liquid L4 was used instead of the low refractive index layer coating liquid L3.

[Example 5]
(Preparation of coating liquid L5 for low refractive index layer)
In Example 1 (Preparation of coating solution L1 for low refractive index layer), Example 5 was used except that 5 parts of 5.0% by mass citric acid aqueous solution was used instead of 5 parts by mass of 5.0% by mass acetic acid aqueous solution. In the same manner as in Example 1, a coating solution L5 for a low refractive index layer was prepared.

(Preparation of sample 5)
In Example 1, Sample 5 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L5 was used instead of the low refractive index layer coating liquid L1.

[Example 6]
(Preparation of coating liquid L6 for low refractive index layer)
In Example 5 (Preparation of coating solution L5 for low refractive index layer), except that the amount of 5.0 mass% citric acid aqueous solution used was changed from 5 parts to 1.43 parts, it was the same as Example 5. Then, the coating liquid L6 for low refractive index layer was prepared.

(Preparation of sample 6)
In Example 5, Sample 6 was produced in the same manner as in Example 5 except that the low refractive index layer coating liquid L6 was used instead of the low refractive index layer coating liquid L5.

[Example 7]
(Preparation of coating solution L7 for low refractive index layer)
In Example 1 (Preparation of coating solution L1 for low refractive index layer), Example 5 was used except that 5 parts of 5.0% by weight malic acid aqueous solution was used instead of 5 parts by weight of 5.0% by weight aqueous acetic acid solution. In the same manner as in Example 1, a coating solution L7 for a low refractive index layer was prepared.

(Preparation of sample 7)
In Example 1, Sample 7 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L7 was used instead of the low refractive index layer coating liquid L1.

[Example 8]
(Preparation of coating liquid L8 for low refractive index layer)
In Example 7 (Preparation of coating solution L7 for low refractive index layer), the same procedure as in Example 7 was conducted, except that the amount of the 5.0% by mass malic acid aqueous solution was changed from 5 parts to 1.43 parts. Then, a coating liquid L8 for low refractive index layer was prepared.

(Preparation of sample 8)
In Example 7, Sample 8 was produced in the same manner as in Example 7, except that the low refractive index layer coating liquid L8 was used instead of the low refractive index layer coating liquid L7.

[Example 9]
(Preparation of coating solution L9 for low refractive index layer)
In Example 1 (Preparation of coating solution L1 for low refractive index layer), instead of an aqueous 5.0 mass% zirconium acetate solution (as ZrO ₂ ), zirconium ammonium carbonate (Zircosol AC-20, Daiichi Rare Element Chemical Industry) A low refractive index layer coating solution L9 was prepared in the same manner as in Example 1, except that an aqueous solution of 5.0% by mass (as ZrO ₂ ) was used.

(Preparation of sample 9)
In Example 1, Sample 9 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L9 was used instead of the low refractive index layer coating liquid L1.

[Example 10]
(Preparation of coating liquid L10 for low refractive index layer)
In Example 9 (Preparation of coating solution L9 for low refractive index layer), except that the amount of 5.0 mass% acetic acid aqueous solution used was changed from 5 parts to 1.67 parts, in the same manner as in Example 9, A coating solution L10 for a low refractive index layer was prepared.

(Preparation of sample 10)
In Example 9, Sample 10 was produced in the same manner as in Example 9, except that the low refractive index layer coating liquid L10 was used instead of the low refractive index layer coating liquid L9.

[Example 11]
(Preparation of coating liquid L11 for low refractive index layer)
In Example 9 (Preparation of coating solution L9 for low refractive index layer), Example 9 was used except that 4 parts of 5.0% by mass lactic acid aqueous solution was used instead of 5 parts by mass of 5.0% by mass acetic acid aqueous solution. In the same manner as described above, a coating solution L11 for a low refractive index layer was prepared.

(Preparation of sample 11)
In Example 9, Sample 11 was produced in the same manner as in Example 9, except that the low refractive index layer coating liquid L11 was used instead of the low refractive index layer coating liquid L9.

[Example 12]
(Preparation of coating liquid L12 for low refractive index layer)
In Example 11 (Preparation of coating solution L11 for low refractive index layer), except that the amount of 5.0 mass% lactic acid aqueous solution used was changed from 4 parts to 1.43 parts, in the same manner as in Example 11, A coating liquid L12 for low refractive index layer was prepared.

(Preparation of sample 12)
In Example 11, Sample 12 was produced in the same manner as in Example 11 except that the low refractive index layer coating liquid L12 was used instead of the low refractive index layer coating liquid L11.

[Example 13]
(Preparation of coating liquid L13 for low refractive index layer)
In Example 9 (Preparation of coating solution L9 for low refractive index layer), Example 5 was used except that 5 parts of 5.0% by mass citric acid aqueous solution were used instead of 5 parts by mass of 5.0% by mass acetic acid aqueous solution. In the same manner as in Example 9, a coating solution L13 for a low refractive index layer was prepared.

(Preparation of Sample 13)
In Example 9, a sample 13 was produced in the same manner as in Example 9 except that the low refractive index layer coating liquid L13 was used instead of the low refractive index layer coating liquid L9.

[Example 14]
(Preparation of coating solution L14 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), except that the amount of 5.0 mass% citric acid aqueous solution was changed from 5 parts to 1.43 parts, it was the same as Example 13 Then, a coating solution L14 for a low refractive index layer was prepared.

(Preparation of sample 14)
In Example 13, Sample 14 was produced in the same manner as in Example 13, except that the low refractive index layer coating liquid L14 was used instead of the low refractive index layer coating liquid L13.

[Example 15]
(Preparation of coating liquid L15 for low refractive index layer)
In Example 9 (Preparation of coating solution L9 for low refractive index layer), Example 5 was used except that 5 parts of 5.0% by weight aqueous solution of malic acid was used instead of 5 parts of 5.0% by weight aqueous solution of acetic acid. In the same manner as in Example 9, a coating solution L15 for a low refractive index layer was prepared.

(Preparation of sample 15)
In Example 9, Sample 15 was prepared in the same manner as in Example 9, except that the low refractive index layer coating liquid L15 was used instead of the low refractive index layer coating liquid L9.

[Example 16]
(Preparation of coating liquid L16 for low refractive index layer)
In Example 15 (Preparation of coating solution L15 for low refractive index layer), except that the amount of the 5.0 mass% malic acid aqueous solution used was changed from 5 parts to 1.43 parts, it was the same as Example 15. Then, the coating liquid L16 for low refractive index layer was prepared.

(Preparation of sample 16)
In Example 15, Sample 16 was produced in the same manner as in Example 7, except that the low refractive index layer coating liquid L16 was used instead of the low refractive index layer coating liquid L15.

[Example 17]
(Preparation of coating liquid L17 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), 5.0 mass of polyvinyl alcohol (PVA124, polymerization degree: 2400, saponification degree: 98.0 to 99.0 mol%, manufactured by Kuraray Co., Ltd.) Example 1 was used except that a 5.0 mass% aqueous solution of polyvinyl alcohol (PVA217, polymerization degree: 1700, saponification degree: 87.0 to 89.0 mol%, manufactured by Kuraray Co., Ltd.) was used instead of the aqueous solution. In the same manner as described above, a coating solution L17 for a low refractive index layer was prepared.

(Preparation of sample 17)
In Example 13, Sample 17 was produced in the same manner as in Example 1 except that the low refractive index layer coating liquid L17 was used instead of the low refractive index layer coating liquid L13.

[Example 18]
(Preparation of coating liquid L18 for low refractive index layer)
The following materials were added in the following composition while being heated to 40 ° C. while being stirred in order to prepare a coating solution L18 for a low refractive index layer.

(Preparation of coating liquid H2 for high refractive index layer)
In the same manner as in Example 1 (Preparation of a high refractive index layer coating solution H2), the core with titanium oxide having a rutile-type structure, the coating layer is SiO _2, 20 wt% sol silica modified titanium oxide particles An aqueous dispersion (silica-modified titanium oxide particle aqueous dispersion) was obtained.

Then, the following materials were added while stirring at 40 ° C. with the following composition in order, to prepare a coating solution H2 for a high refractive index layer.

(Preparation of sample 18)
In Example 1, the low refractive index layer coating liquid L18 instead of the low refractive index layer coating liquid L1, and the high refractive index layer coating liquid H2 instead of the high refractive index layer coating liquid H1, Sample 18 was produced in the same manner as in Example 1 except that each was used.

[Comparative Example 1]
(Preparation of coating liquid L19 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), coating solution L19 for low refractive index layer was prepared in the same manner as Example 13 except that citric acid was not used.

(Preparation of Sample 19)
In Example 13, Sample 19 was produced in the same manner as in Example 13, except that the low refractive index layer coating liquid L19 was used instead of the low refractive index layer coating liquid L13.

[Comparative Example 2]
(Preparation of coating liquid L20 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), a coating solution L20 for low refractive index layer was prepared in the same manner as Example 13 except that ammonium zirconium carbonate and citric acid were not used. did.

(Preparation of sample 20)
In Example 13, Sample 20 was produced in the same manner as Example 13 except that the low refractive index layer coating liquid L20 was used instead of the low refractive index layer coating liquid L13.

[Comparative Example 3]
(Preparation of coating liquid L21 for low refractive index layer)
In Example 13 (Preparation of low refractive index layer coating liquid L13), a low refractive index layer coating liquid L21 was prepared in the same manner as in Example 13, except that ammonium zirconium carbonate was not used.

(Preparation of sample 21)
In Example 13, Sample 21 was produced in the same manner as in Example 13, except that the low refractive index layer coating liquid L21 was used instead of the low refractive index layer coating liquid L13.

[Comparative Example 4]
(Preparation of coating liquid L22 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), the amount of citric acid aqueous solution of 5.0% by mass was changed from 5 parts to 20 parts in the same manner as in Example 13 except that A refractive index layer coating solution L22 was prepared.

(Preparation of sample 22)
In Example 13, Sample 22 was produced in the same manner as in Example 13, except that the low refractive index layer coating liquid L22 was used instead of the low refractive index layer coating liquid L13.

[Comparative Example 5]
(Preparation of coating liquid L23 for low refractive index layer)
In Example 13 (Preparation of coating solution L13 for low refractive index layer), except that the amount of 5.0 mass% citric acid aqueous solution used was changed from 5 parts to 1.18 parts, the same as Example 13 Then, a coating solution L23 for a low refractive index layer was prepared.

(Preparation of sample 23)
In Example 13, Sample 23 was produced in the same manner as in Example 13, except that the low refractive index layer coating liquid L23 was used instead of the low refractive index layer coating liquid L13.

<Evaluation of infrared shielding film>
The following performance evaluation was performed about the coating liquid for refractive index layers containing the water-soluble zirconium compound used above, and each infrared shielding film produced above. The results are shown in Table 1 below. In addition, about the comparative examples 2 and 3, the following performance evaluation was performed about the coating liquid for low refractive index layers.

(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 side on the measurement side of each sample is roughened, and then light absorption treatment is performed with a black spray to reflect light on the back side. 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 23 was 0.3 or more.

(Measurement of visible light transmittance and infrared transmittance)
Using a spectrophotometer (using an integrating sphere, manufactured by Hitachi, Ltd., U-4000 type), the visible light transmittance and the infrared transmittance in the region of 300 nm to 2000 nm of each infrared shielding film sample were measured.

(Measurement of haze value)
The haze value was measured as follows by measuring the infrared shielding film samples 1 to 23 with a haze meter (NDH 2000, manufactured by Nippon Denshoku Industries Co., Ltd.). In this example and the comparative example, when the coating solution was applied after being stagnated, the haze tends to be deteriorated.

(Liquid stability)
The coating solution for refractive index layer containing the water-soluble zirconium compound used above was stagnated for 20 hours at 40 ° C., and the state of the liquid after stagnation was observed and evaluated as follows. In Comparative Examples 2 and 3, a coating solution for a low refractive index layer was used.

(Applicability)
The interference unevenness of the coated surface (film surface) of the infrared shielding film sample was placed on black paper, visually observed, and evaluated as follows.

From Table 1 above, it can be seen that the infrared blocking film samples 1 to 18 of the present invention have better coating properties and lower haze than the infrared blocking film samples 19 to 23 of the comparative example.

<Production of infrared shielding body>
[Example 19]
[Fabrication of infrared shields 101 to 118]
A hard coat layer was provided on the infrared shielding films of Samples 1 to 18 produced in Examples 1 to 18 as shown below, and an acrylic adhesive layer was provided on the side opposite to the hard coat layer. Infrared shields 101 to 118 were produced 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 118 of the present invention produced above were able to confirm excellent infrared shielding properties.

Furthermore, this application is based on Japanese Patent Application No. 2012-242596 filed on November 2, 2012, the disclosure of which is incorporated by reference in its entirety.

Claims (6)

An optical reflective film having a base material and a reflective layer that reflects at least infrared 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 that of an adjacent refractive index layer;
Of the refractive index layers constituting the reflective layer, at least one of the refractive index layers contains metal oxide fine particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol-based resin,
An optical reflection film having a mixing ratio of the water-soluble zirconium compound and the carboxylic acid (water-soluble zirconium compound (solid content in terms of zirconia): carboxylic acid solid content (mass ratio)) of 2 to 16: 1. The optical reflective film according to claim 1, wherein the carboxylic acid is a polyvalent carboxylic acid. The optical reflective film according to claim 1 or 2, wherein the average degree of polymerization of the polyvinyl alcohol-based resin is 2000 or more. The reflective layer has at least one laminate in which low refractive index layers and high refractive index layers having different refractive indexes are alternately laminated,
The optical reflective film according to any one of claims 1 to 3, wherein the low refractive index layer contains fine metal oxide particles, a water-soluble zirconium compound, a carboxylic acid, and a polyvinyl alcohol-based resin. The optical reflection film according to any one of claims 1 to 4, which is an infrared shielding film. An infrared shielding body using the optical reflecting film according to claim 5.