JP2013125076A - Near-infrared shielding film and near-infrared shielding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near-infrared shielding film eliminating glare due to reflection, having high visible light transmittance, excellent near infrared shielding property, and a low production cost, capable of enlarging an area, and having excellent film flexibility or excellent durability, and to provide a near infrared shielding body including the near infrared shielding film.SOLUTION: The near-infrared shielding film comprises: a base material; and a laminated body formed by laminating, on the base material, a high refractive index layer including a first water-soluble binder resin and first metal oxide particles, a low refractive index layer including a second water-soluble binder resin and second metal oxide particles, and a partition layer interposed between the high refractive index layer and the low refractive index layer. A difference in the refractive indices between the high refractive index layer and the low refractive index layer is 0.1 or more.

Description

  The present invention relates to a near infrared shielding film and a near infrared shielding body.

  In recent years, as part of energy-saving measures, from the viewpoint of reducing the load on cooling equipment, to a near-infrared shielding film that is attached to the window glass of buildings and vehicles and shields the transmission of solar heat rays (also called near-infrared rays) The demand for is increasing.

  The near-infrared shielding film is a laminated body having a configuration in which high refractive index layers and low refractive index layers are alternately laminated, and is realized based on the characteristics of light. Further, in the near-infrared shielding film, the reflectance in a specific wavelength region is determined by the refractive index difference between these two adjacent layers and the number of layers, and the larger the refractive index difference, the better the reflectance with a smaller number of layers. .

  In recent years, many near-infrared shielding films that shield near-infrared rays and transmit visible light as described above have been developed and manufactured. As a method for forming such a near-infrared shielding film, a laminate unit composed of a structure in which high-refractive index layers and low-refractive index layers are alternately stacked is mainly used for vacuum deposition, sputtering, etc. It is known to form using a dry film forming method or a wet coating method. However, when the near-infrared shielding film is designed by the conventional technique (dry film forming method) so that infrared rays are reflected, since the high-order reflection is shown in the visible light range, the appearance of the film exhibits a rainbow color, Patent Document 1 reports that the problem of glare occurs.

  Further, this Patent Document 1 solves the problem that a dry film forming method such as a vacuum deposition method or a sputtering method requires a large vacuum apparatus or the like for formation, which increases the manufacturing cost and makes it difficult to increase the area. A multilayer optical film is disclosed that includes repeating units of m-layers (m is an integer of 4 or more) laminated from three different polymer materials.

  Furthermore, in Patent Document 1, the film of Patent Document 1 uses a plurality of types of layers, and by laminating a plurality of these layers, high-order reflection of visible light can be suppressed, and the appearance of the film Discloses that it was possible to prevent the appearance of rainbow colors, and it is also disclosed that a large apparatus is not required.

JP-A-4-313704

  In the case of producing a film by a dry film forming method, the film of Patent Document 1 has a layer made of three different types of polymers, so that glare caused by visible light may be suppressed to some extent, but the wet type In the near-infrared shielding film when metal oxide particles are used for the high refractive index layer or the low refractive index layer by the coating method, simply increasing the number of layers containing metal oxide particles having different refractive indexes can reduce glare. Insufficient to suppress.

  Because, in the wet coating method in which the metal oxide particles are mixed with the water-soluble binder resin and the high refractive index layer and the low refractive index layer are alternately laminated, interlayer mixing between the coating liquids occurs between two adjacent layers, Furthermore, since the interlayer aggregation or interlayer diffusion of the metal oxide particles occurs, the unevenness of the interface between the high refractive index layer and the low refractive index layer inside the film and the interlayer interface on the film surface cannot be suppressed.

  As a result, there has been a problem that the glare derived from the unevenness of the interlayer interface particularly in the film occurs despite the multilayer structure of different types of layers.

  Therefore, the present invention has been made in view of the above-mentioned problems, and its purpose is to suppress the interlayer diffusion of metal oxide particles, to prevent glare due to reflection, and to maintain high visible light transmittance. An object of the present invention is to provide a near-infrared shielding film that can achieve a near-infrared shielding rate.

  The above object of the present invention is achieved by the following configurations.

  (1) A substrate, a high refractive index layer containing a first water-soluble binder resin and first metal oxide particles, a low refractive index layer containing a second water-soluble binder resin and second metal oxide particles And a laminate formed on the base material with a partition layer interposed between the high refractive index layer and the low refractive index layer, and the high refractive index layer and the low refractive index layer, The near-infrared shielding film has a refractive index difference of 0.1 or more.

  (2) The near-infrared shielding film according to (1), wherein a refractive index of the partition layer is equal to or lower than a refractive index of the high refractive index layer and equal to or higher than a refractive index of the low refractive index layer.

  (3) The (1) layered from the base material in the order of one of the low refractive index layer or the high refractive index layer, the partition layer, and the other of the low refractive index layer or the high refractive index layer. Or the near-infrared shielding film as described in (2).

  (4) The near-infrared shielding film according to any one of (1) to (3), wherein the partition layer includes a resin component including only a third water-soluble binder resin.

  (5) The near-infrared shielding film according to (4), wherein the third water-soluble binder resin does not have a reactive functional group that reacts with the first or second water-soluble binder resin.

  (6) The near-infrared shielding film according to (4) or (5), wherein the third water-soluble binder resin is a polyethylene oxide resin.

  (7) The near-infrared shielding film according to any one of (1) to (6), wherein the partition layer has a thickness of 1 nm to 50 nm.

  (8) In any one of (1) to (7), the first metal oxide particles are rutile-type titanium oxide particles, and the second metal oxide particles are silica particles. The near-infrared shielding film as described.

  (9) A near-infrared shielding body comprising the near-infrared shielding film according to any one of (1) to (8) provided on at least one surface of a substrate.

  According to the present invention, an aqueous refractive index forming coating solution is used, without causing interlayer diffusion of metal oxide particles, no glare due to reflection, high visible light transmittance, and excellent near-infrared shielding, Moreover, the near-infrared shielding film excellent in durability and the near-infrared shielding body provided with the near-infrared shielding film can be provided.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

  The first aspect of the present invention includes a base material, a high refractive index layer including a first water-soluble binder resin and first metal oxide particles, a second water-soluble binder resin and second metal oxide particles. A low-refractive-index layer, and a laminate formed on the substrate with a partition layer interposed between the high-refractive-index layer and the low-refractive-index layer, and the high-refractive-index layer and the low-refractive-index layer The near-infrared shielding film has a refractive index difference of 0.1 or more with respect to the refractive index layer.

  In the near-infrared shielding film of the present invention, an interlayer between the first metal oxide particles and the second metal oxide particles by interposing a partition layer between the high refractive index layer and the low refractive index layer. Aggregation or interlayer diffusion is suppressed / prevented, and is considered to be a film in which interlayer mixing between the high refractive index layer and the low refractive index layer is reduced. Therefore, the interfacial unevenness is reduced by inter-layer mixing, and internal glare (“glare” in this specification is a phenomenon that becomes a rainbow color by reflection) due to irregular reflection of light of the unevenness is suppressed. .

  The mechanism for exerting the main effects by the above-described configuration of the present invention is assumed as follows.

  That is, the near-infrared shielding film targeted by the present invention usually uses respective coating liquids that can form a high refractive index layer and a low refractive index layer, and a unit composed of each coating liquid has a sequential multilayer structure. Thus, it is manufactured with high productivity. And when using an aqueous coating solution unit, ensure the refractive index designed for each layer by preventing the coating solution components of the high refractive index layer and low refractive index layer from mixing together as much as possible. There is a need to. For that purpose, it is important to suppress interlayer mixing due to diffusion of metal oxide particles between the coating liquid units.

  However, in the aqueous coating solution unit, the coating solution of each layer is in liquid contact during coating and drying, so that mixing occurs at the interface, so that the refractive index difference between the layers is reduced. Further, when rapid drying is performed to obtain a refractive index difference, the film surface is glazed.

  In contrast, in the near-infrared shielding film according to the present invention, mixing at the coating liquid interface is suppressed by having a partition layer between the high refractive index layer and the low refractive index layer, and the low refractive index layer. By the fact that the second metal oxide particles and the first metal oxide particles of the high refractive index layer are not substantially mixed, there is no microscopic refractive index disturbance or unevenness at the interface. It is considered that the visual reflection glare generated on the film surface disappeared.

  In addition, since the near-infrared shielding film according to the present invention can be manufactured using a water-based coating solution for forming a refractive index, the manufacturing cost is low, the area can be increased, and the film flexibility is excellent. Have.

  Hereinafter, the component of the near-infrared shielding film of this invention, the form for implementing this invention, etc. are demonstrated in detail.

{Near-infrared shielding film}
In the near-infrared shielding film of the present invention, a base material, a high refractive index layer, a low refractive index layer, and a partition layer interposed between the high refractive index layer and the low refractive index layer are formed on the base material. And a laminated body.

  The near-infrared shielding film of the present invention is formed by laminating a high refractive index layer, a low refractive index layer, and a partition layer interposed between the high refractive index layer and the low refractive index layer on a substrate. As long as the total number of layers of the high refractive index layer, the low refractive index layer and the partition layer is preferable, from the viewpoint of productivity, the number of layers is preferably 50 layers or less, 10 layers or more. Preferably they are 30 layers or less and 10 layers or more, More preferably, they are 20 layers or less and 10 layers or more.

  The laminate according to the present invention is formed by laminating at least one high refractive index layer, low refractive index layer, and partition layer. A laminate in which a partition layer is interposed between all high refractive index layers and all low refractive index layers is preferred, and all high refractive index layers and all low refractive index layers are alternately laminated, and A laminate in which partition layers are interposed between all the layers is more preferable. The thickness of the laminate itself of the present invention is preferably 41 nm to 1650 nm, and more preferably 101 nm to 710 nm.

  The near-infrared shielding film of the present invention includes the low refractive index layer or the low refractive index layer, the partition layer, and the low refractive index layer or the other one of the high refractive index layer in this order. It is preferable to be laminated. Furthermore, it is more preferable to laminate | stack from the said base material in order of the said low refractive index layer, the said partition layer, and the said high refractive index layer. The near-infrared shielding film of the present invention is used for the purpose of further function addition, for example, to improve adhesion between the base material and the low refractive index layer or the high refractive index layer which is the lowermost layer of the laminate. A known sheet or layer may be inserted.

  In general, in the near-infrared shielding film, it is possible to design a large difference in refractive index between the high refractive index layer and the low refractive index layer from the viewpoint that the near infrared reflectance can be increased with a small number of layers. preferable. In the present invention, the difference in refractive index between the high refractive index layer and the low refractive index layer is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.35 or more, and particularly preferably 0. .4 or more. The refractive index of the partition layer of the present invention is preferably not less than the refractive index of the high refractive index layer and not more than the low refractive index layer.

  When the near-infrared shielding film is formed by alternately laminating a high refractive index layer and a low refractive index layer, it is preferable that the refractive index difference between the high refractive index layer and the low refractive index layer is within the above preferable range. . However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used.

  In general, the reflectance in a specific wavelength region is determined by the difference in refractive index between two adjacent layers (high refractive index layer and low refractive index layer) and the number of layers. The larger the difference in refractive index, the smaller the number of layers. You can get a rate. The present invention also relates to the difference in refractive index between the partition layer and the adjacent high refractive index layer, or the difference in refractive index between the partition layer and the adjacent low refractive index layer. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain a near-infrared reflectance of 90% or more, if the difference in refractive index is smaller than 0.1, it is necessary to laminate 200 layers or more, which not only reduces productivity, but also at the lamination interface. Scattering increases, transparency decreases, 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 near-infrared shielding film of the present invention, the transmittance in the visible light region shown in JIS R3106-1998 is 50% or more, preferably 75% or more, more preferably 85% or more. It is. Moreover, it is preferable to have the area | region exceeding a reflectance of 50% in the area | region of wavelength 900nm-1400nm.

  The total thickness of the near-infrared shielding film of the present invention is preferably 12 μm to 315 μm, more preferably 15 μm to 200 μm, and still more preferably 20 μm to 100 μm.

  Next, components included in each element will be described in detail with respect to the high refractive index layer, the low refractive index layer, the partition layer, and the base material, which are constituent elements of the near-infrared shielding film of the present invention.

<High refractive index layer>
The high refractive index layer according to the present invention contains the first water-soluble binder resin and the first metal oxide particles as essential components, and if necessary, a curing agent, a surface coating component, a binder resin, a surfactant, and various types It may further include at least one selected from the group consisting of additives.

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

  The thickness per layer of the high refractive index layer according to the present invention is preferably 20 nm to 800 nm, and more preferably 50 nm to 350 nm.

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

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

  The weight average molecular weight of the first water-soluble binder resin according to the present invention is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 40,000 or less are more preferable.

  The weight average molecular weight in the present invention can be measured by a known method, for example, it can be measured by static light scattering, gel permeation chromatography (GPC), TOF-MASS, etc. It is measured by a gel permeation chromatograph method (GPC method) which is a publicly known method.

  The first water-soluble binder resin according to the present invention particularly preferably contains polyvinyl alcohol. Below, polyvinyl alcohol is demonstrated.

  The polyvinyl alcohol preferably used in the present invention includes various modified polyvinyl alcohols in addition to normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. Examples thereof include polyvinyl alcohol having a terminal cation modified, an anion modified polyvinyl alcohol having an anionic group, and the like.

  The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The degree of saponification is preferably 70 to 100%, particularly preferably 80 to 99.5%.

  Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups, as described in JP-A No. 61-10383, in the main chain or side chain of the polyvinyl alcohol. It 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, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

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

  Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. The block copolymer of the vinyl compound and vinyl alcohol which have the described hydrophobic group is mentioned. Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.

  In the present invention, the first water-soluble binder resin is preferably contained in a range of 5.0% by mass to 50% by mass with respect to 100% by mass of the solid content of the high refractive index layer, It is more preferable to make it contain in 10 mass% or more and 40 mass% or less. However, when using together with water-soluble binder resin, for example, emulsion resin, it should just contain 3.0 mass% or more. If the amount of water-soluble polymer is small, the film surface is disturbed and the transparency tends to deteriorate during drying after coating the refractive index layer. 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.

  Moreover, in this invention, you may contain the hardening | curing agent demonstrated below. For example, in the case where the above-described polyvinyl alcohol is used as the first water-soluble binder resin, boric acid and salts thereof, borax, an epoxy curing agent, and the like are preferable as the curing agent. The curing agent will be described in detail later.

"First metal oxide particles"
The first metal oxide particles according to the present invention are preferably metal oxide particles having a refractive index of 2.0 or more and 3.0 or less. More specifically, for example, titanium dioxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, second oxide Examples include iron, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Also, composite oxide particles composed of a plurality of metals, core-shell particles whose metal structure changes into a core-shell shape, and the like can be used.

  In order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer of the present invention includes metal oxide fine particles having a high refractive index such as titanium and zirconia, that is, titanium oxide fine particles and zirconia oxide. It is preferable to contain fine particles, but they can be used in combination. Among these, titanium oxide is preferable from the viewpoint of the stability of the coating liquid for forming the high refractive index layer. Among titanium oxides, the rutile type (tetragonal type) has a lower catalytic activity than the anatase type, and the weather resistance of the high refractive index layer and adjacent layers is higher, and the refractive index is higher. Is more preferable. In the case of using core-shell particles as the first metal oxide particles in the high refractive index layer of the present invention, due to the interaction between the silicon-containing hydrated oxide of the shell layer and the first water-soluble binder resin, From the effect of suppressing interlayer mixing between the high refractive index layer and the adjacent layer, core-shell particles in which titanium oxide particles are coated with a silicon-containing hydrated oxide are more preferable.

  In the present invention, the volume average particle size of the first metal oxide particles is preferably 100 nm or less, more preferably 1 nm to 50 nm, and even more preferably 1 nm to 20 nm. A volume average particle diameter of 1 nm or more and 10 nm or less is preferable from the viewpoint of low haze and excellent visible light transmittance.

  The volume average particle size here refers to a method of observing the particle itself using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, or a particle image appearing on the cross section or surface of the refractive index layer. The particle diameters of 1,000 arbitrary particles are measured by the method of observing the above, and particles having particle diameters of d1, d2,. The average particle size weighted by the volume represented by the following formula 1 when the volume per particle in a group of nk particulate metal oxides is vi.

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

  The first metal oxide particles according to the present invention are preferably surface-coated with a surface coating component. When the surface of the first metal oxide particles is coated with a surface coating component, it is considered that the compatibility and dispersibility with the first water-soluble resin are improved.

  As the surface coating component, aminocarboxylic acids such as picolinic acid, aminopolycarboxylic acids, pyridine derivatives and collagen peptides, low molecular gelatin and the like are preferable. Of these, a pyridine derivative, a low molecular weight gelatin having an average molecular weight of 30,000 or less, or a collagen peptide is most preferable. In order to reduce shock when adding low molecular gelatin or the like, a particulate first metal is previously used. It is possible to coat the oxide particles with two or more types such as coating the surface of the oxide particles with polyaluminum chloride or the like.

  In the present invention, the aqueous high-refractive index layer coating liquid used in producing the infrared shielding film has a pH of 1.0 to 3.0 as the titanium oxide particles used in the core of the core-shell particles. In addition, it is preferable to use a surface of an aqueous titanium oxide sol in which the zeta potential of titanium particles is positive so that the surface can be dispersed in an organic solvent.

  The rutile titanium oxide used in the present invention may be a synthetic product or a commercial product. Examples of a method for preparing an aqueous titanium oxide sol that can be used in the present invention include JP-A 63-17221, JP-A 7-819, JP-A 9-165218, and JP-A 11-43327. Reference can be made to the matters described in Japanese Patent Laid-Open Nos. 63-17221, 7-819, 9-165218, 11-43327, and the like.

  In addition, as for other production methods of titanium oxide particles used in the present invention, for example, “Titanium oxide—physical properties and applied technology” Manabu Seino p255-258 (2000) Gihodo Publishing Co., Ltd. or WO2007 / 039953 The method of the step (2) described in paragraph Nos. 0011 to 0023 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. In the present invention, an aqueous sol of titanium oxide having a pH adjusted to 1.0 to 3.0 with the inorganic acid obtained in the step (2) can be used.

  It is preferable that content of the 1st metal oxide particle in the high refractive index layer which concerns on this invention is 15-70 mass% with respect to solid content of 100 mass% of a high refractive index layer, 20-65 mass. % Is more preferable, and 30 to 60% by mass is even more preferable.

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

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

"Binder resin"
In the high refractive index layer according to the present invention, as the binder resin other than the first water-soluble binder resin, if the high refractive index layer containing the first metal oxide particles can form a coating film, any method can be used. Anything can be used without limitation. However, in view of environmental problems and flexibility of the coating film, water-soluble polymers (particularly gelatin, thickening polysaccharides, polymers having reactive functional groups) are preferable. These water-soluble polymers may be used alone or in combination of two or more.

  In the high refractive index layer, the content of other binder resin used together with polyvinyl alcohol preferably used as the first water-soluble binder is 0 to 10% by mass with respect to 100% by mass of the solid content of the high refractive index layer. Can also be used.

  In the near-infrared shielding film of the present invention, the high refractive index layer and the low refractive index layer may further contain water-soluble polymers such as celluloses, thickening polysaccharides, and polymers having reactive functional groups. it can. Hereinafter, each water-soluble polymer will be described.

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

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

  The thickening polysaccharide referred to in the present invention is a polymer of saccharides and has many hydrogen bonding groups in the molecule, and the viscosity at low temperature and the viscosity at high temperature due to the difference in hydrogen bonding force between molecules depending on the temperature. It is a polysaccharide with a large difference in characteristics, and when adding metal oxide fine particles, it causes a viscosity increase that seems to be due to hydrogen bonding with the metal oxide fine particles at a low temperature. When added, it is a polysaccharide that increases its viscosity at 15 ° C. by 1.0 mPa · s or more, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more. Polysaccharides.

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

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

(Polymers having reactive functional groups)
Examples of the water-soluble polymer applicable to the present invention include polymers having reactive functional groups, such as polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile. Acrylic resin such as copolymer, vinyl acetate-acrylic acid ester copolymer, or acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid -Styrene acrylic resin such as acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, or styrene-α-methylstyrene-acrylic acid-acrylic ester copolymer, styrene-styrenesulfonic acid Sodium copolymer, styrene-2-hydroxyethyl Acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene -Vinyl acetate copolymers such as maleic acid copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, and salts thereof. Among these, particularly preferred examples include polyvinylpyrrolidones and copolymers containing the same.

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

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

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

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

  In the present invention, it is preferable to use boric acid and a salt thereof and / or borax in order to obtain the effects of the present invention. When boric acid and its salt and / or borax are used, metal oxide particles and water-soluble binder resin polyvinyl alcohol OH group and hydrogen bond network are more easily formed, and as a result, a high refractive index layer Alternatively, it is considered that interlayer mixing between the low refractive index layer and its adjacent layer is suppressed, and preferable near-infrared shielding characteristics 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.

  When the polyvinyl alcohol is used as the first water-soluble binder resin, the total amount of the curing agent used is preferably 1 to 600 mg per 1 g of polyvinyl alcohol, and more preferably 100 to 600 mg per 1 g of polyvinyl alcohol.

"Additive"
Various additives can be used in the high refractive index layer according to the present invention and the low refractive index layer described later, if necessary. Moreover, it is preferable that content of the additive in a high refractive index layer is 0-20 mass% with respect to 100 mass% of solid content of a high refractive index layer. Examples of such additives are described below.

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

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

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

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

  The isoelectric point of an amino acid means this pH value because an amino acid balances positive and negative charges in a molecule at a specific pH, and the overall charge becomes zero. The isoelectric point of each amino acid can be determined by isoelectric focusing at a low ionic strength.

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

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

  The polymer dispersant containing a hydroxyl group is a polymer dispersant having a weight average molecular weight of 10,000 or more, and has a hydroxyl group substituted at the side chain or terminal. For example, an acrylic polymer such as sodium polyacrylate or polyacrylamide is used. Examples of such a polymer include those obtained by copolymerization of 2-ethylhexyl acrylate, polyethers such as polyethylene glycol and polypropylene glycol, and polyvinyl alcohol. Polyvinyl alcohol is particularly preferable.

  Polyvinyl alcohol used as a polymer dispersant is an anion-modified polyvinyl alcohol having an anionic group such as a cation-modified polyvinyl alcohol or a carboxyl group in addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate. Further, modified polyvinyl alcohol such as silyl-modified polyvinyl alcohol having a silyl group is also included. Polyvinyl alcohol has a higher effect of suppressing the occurrence of cracks when forming the ink absorbing layer when the average degree of polymerization is higher, but when the average degree of polymerization is within 5000, the viscosity of the emulsion resin is not high, and at the time of production Easy to handle. Accordingly, the average degree of polymerization is preferably 300 to 5000, more preferably 1500 to 5000, and particularly preferably 3000 to 4500. The saponification degree of polyvinyl alcohol is preferably 70 to 100 mol%, more preferably 80 to 99.5 mol%.

  Examples of the resin that is emulsion-polymerized with the above polymer dispersant include homopolymers or copolymers of ethylene monomers such as acrylic acid esters, methacrylic acid esters, vinyl compounds, and styrene compounds, and diene compounds such as butadiene and isoprene. Examples of the polymer include acrylic resins, styrene-butadiene resins, and ethylene-vinyl acetate resins.

  In addition, the high refractive index layer according to the present invention or the low refractive index layer described later includes, for example, an ultraviolet ray described in JP-A-57-74193, 57-87988 and 62-261476. Absorbents, described in JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091 and JP-A-3-13376 Anti-fading agents, various anionic, cationic or nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871, and JP-A Fluorescent whitening agent, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, carbonate pH adjusting agents such as um, antifoaming agents, lubricants such as diethylene glycol, preservatives, antistatic agents, may contain various known additives such as a matting agent.

<Low refractive index layer>
The low refractive index layer according to the present invention contains the second water-soluble binder resin and the second metal oxide particles as essential components, and optionally comprises a curing agent, a binder resin, a surfactant, and various additives. It may contain at least one selected from

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

  The thickness per layer of the low refractive index layer according to the present invention is preferably 20 to 800 nm, and more preferably 50 to 350 nm.

"Second water-soluble binder resin"
Specific examples, preferable weight average molecular weights, and the like of the second water-soluble binder resin according to the present invention are the same as the contents described in the column of the first water-soluble binder resin, and thus the description thereof is omitted here.

  The content of the second water-soluble binder resin in the low refractive index layer is preferably 1 to 99.9% by mass and 1 to 50% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably.

"Second metal oxide particles"
As the second metal oxide particles according to the present invention, metal oxide particles having a refractive index of 1.0 or more and 1.7 or less are preferable. For example, silica (silicon dioxide) is preferably used. Specific examples include synthetic amorphous silica and colloidal silica. Of these, acidic colloidal silica sol is more preferably used, and colloidal silica sol dispersed in an organic solvent is more preferably used.

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

  In the present invention, the average particle size of the second 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 determining the particle size of 1,000 arbitrary particles. 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-60-219084, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 No. 5, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142. , JP-A-7-179029, JP-A-7-137431, and WO94 / 26530 pamphlet. Those which are.

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

  The content of the second metal oxide particles in the low refractive index layer is preferably 0.1 to 50% by mass, and 0.5 to 45% by mass with respect to 100% by mass of the solid content of the low refractive index layer. % Is more preferable, 1 to 40% by mass is further preferable, and 5 to 30% by mass is particularly preferable.

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

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

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

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

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

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

  Further, since specific examples of the curing agent are the same as those of the above-described high refractive index layer, they are omitted here.

"Additive"
Various additives can be used in the low refractive index layer according to the present invention as needed, and the various additives in the low refractive index layer are the same as the additives used in the high refractive index layer. Is omitted here.

<Partition layer>
A partition layer is interposed between the high refractive index layer and the low refractive index layer of the present invention.

  In this specification, the “partition layer” is a layer that suppresses interlayer mixing between the high refractive index layer and the low refractive index layer according to the present invention, that is, interlayer diffusion of the first and second metal oxide particles. It is a layer which suppresses. Furthermore, the partition layer of the present invention preferably exhibits a refractive index value between the refractive index of the high refractive index layer and the refractive index of the low refractive index layer. Furthermore, it is preferable that the partition layer according to the present invention does not substantially contribute to the reflection characteristics to near infrared rays having a wavelength of 1000 nm or more and less than 1300 nm.

  The refractive index of the partition layer according to the present invention is preferably not more than the refractive index of the high refractive index layer and not less than the refractive index of the low refractive index layer, more preferably less than the refractive index of the high refractive index layer, In addition, the refractive index of the low refractive index layer is exceeded. Specifically, it is preferably 1.4 to 2.5, and more preferably 1.4 to 2.0. Furthermore, when the refractive index of the partition layer of the present invention is not more than the refractive index of the high refractive index layer and not less than the refractive index of the low refractive index layer, two layers having different refractive indices can be used as the near infrared shielding film. It is more than the kind, and the rainbow-colored reflection glare on the film surface can be suppressed.

  The thickness per layer of the partition layer according to the present invention is 1 nm or more and 50 nm or less. Preferably they are 1 nm-30 nm, More preferably, they are 1 nm-10 nm. When the film thickness as the partition layer of the present invention is 50 nm or more, there is a risk of producing a reflection characteristic to near infrared rays.

  The structure of the partition layer according to the present invention is not particularly limited as long as it contains a resin component consisting only of the third water-soluble binder resin as an essential component. The third water-soluble binder resin of the present invention will be described in detail below. The partition layer of the present invention may contain metal oxide particles as long as the effects of the present invention are not impaired. For example, oxide particles such as titanium oxide, silicon oxide, and zirconium oxide can be contained. However, the amount of metal oxide particles that can be contained in the partition layer of the present invention is preferably lower than the concentration of the first oxide particles in the high refractive index layer and the second oxide particles in the low refractive index layer. . Specifically, it is preferable that it is 1-30 mass% with respect to 100 mass% of solid content of a partition layer. If it is this range, it is thought that the oxide particle of an adjacent layer can be suppressed and glare can be suppressed. Moreover, although it changes with the kind or refractive index of the said metal oxide particle, if it is in said range of the allowable refractive index of the partition layer of this invention, it will not restrict | limit in particular. In addition, it is more preferable not to contain metal oxide particles in the partition layer of the present invention from the viewpoint of suppressing interlayer diffusion of metal oxide particles.

"Third water-soluble binder resin"
The third water-soluble binder resin according to the present invention does not have a reactive functional group that reacts with the first or second water-soluble binder resin used in the present invention, and increases the viscosity at a low concentration in an aqueous solution. What can be achieved is preferred. Specifically, examples of the water-soluble binder resin include polyvinyl alcohol resins such as polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and polyvinyl acetal, methyl cellulose, and ethyl cellulose. , Cellulose resins such as hydroxyethyl cellulose, carboxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, resins having an ether bond such as polyethylene oxide, polypropylene oxide, polyethylene glycol, polyvinyl ether, polyacrylamide, polyvinyl pyrrolidone, Polyac Resins, chitins having carbamoyl group such as Le acid Hidoajido, chitosan, starch and the like. Among these, for example, when using a polyvinyl alcohol-based resin, it is preferable to add boric acid as described above in order to suppress diffusion of metal oxide particles. In addition, from the viewpoint of maintaining an appropriate viscosity and a preferable film thickness, a polyethylene oxide resin is preferable as the third water-soluble binder resin of the present invention. Hereinafter, the reason will be described in detail.

  In this specification, the term “appropriate viscosity” refers to a resin having a high effect of suppressing the diffusion of metal oxide particles even when the moisture content is reduced in the course of drying, even if the water content is reduced. Is the nature. On the other hand, if the viscosity is too high, it has a spinnability and may affect the coating property. Since the polyethylene oxide resin has such properties, it can be preferably used as the third water-soluble binder resin of the present invention. The polyethylene oxide resin has a spinnability when the viscosity is too high, and the weight average molecular weight is preferably 500,000 to 3,000,000, preferably 500,000 to 2,500,000, considering the possibility of affecting the coating property. More preferred. On the other hand, in order that the partition layer concerning this invention may maintain the preferable film thickness mentioned below, it is better that there are few additives in the said partition layer. That is, when a polyethylene oxide resin is used, an additive such as boric acid is added unlike the case of a polyvinyl alcohol resin because the diffusion preventing effect of the metal oxide particles of the polyethylene oxide resin is high even when the water content is reduced. Even without the addition, diffusion of oxide particles in the adjacent layer can be suppressed.

  The content of the third water-soluble binder resin in the partition layer is preferably 50 to 100% by mass and more preferably 80 to 100% by mass with respect to 100% by mass of the solid content of the partition layer.

<Base material>
The thickness of the base material that is the support of the infrared shielding film according to the present invention is preferably 5 μm to 200 μm, more preferably 15 μm to 150 μm. Moreover, the base material which concerns on this invention may be what piled up two sheets, and the kind may be the same or different in this case.

  The substrate applied to the infrared shielding film of the present invention is not particularly limited as long as it is transparent, and various resin films can be used. For example, methacrylic acid ester, polyethylene terephthalate (PET), polyethylene Films made of resins such as naphthalate (PEN), polycarbonate (PC), polyarylate, polystyrene (PS), aromatic polyamide, polyetheretherketone, polysulfone, polyethersulfone, polyimide, polyetherimide, and the resin And a resin film obtained by laminating two or more layers. From the viewpoint of cost and availability, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC) and the like are preferably used.

  The substrate preferably has a visible light transmittance of 85% or more as shown in JIS R3106-1998, particularly preferably 90% or more. It is advantageous and preferable in that the transmittance of the visible light region shown in JIS R3106-1998 is 50% or more when the base material is equal to or higher than the above-described transmittance.

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

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

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

It is preferable that the substrate is coated with the undercoat layer coating solution inline on one side or both sides during the film forming process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating. Examples of resins used in the undercoat layer coating solution useful in the present invention include polyester resins, acrylic-modified polyester resins, polyurethane resins, acrylic resins, vinyl resins, vinylidene chloride resins, polyethyleneimine vinylidene resins, polyethyleneimine resins, and polyvinyl alcohol resins. , Modified polyvinyl alcohol resin, gelatin and the like, and any of them can be preferably used. A conventionally well-known additive can also be added to these undercoat layers. The undercoat layer can be coated by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating. The coating amount of the undercoat layer is preferably about 0.01 to ² g / m ² (dry state).

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

{Near-infrared shielding film manufacturing method}
There is no restriction | limiting in particular about the manufacturing method of the near-infrared shielding film of this invention, The partition layer interposed between a high refractive index layer, a low refractive index layer, and a high refractive index layer and a low refractive index layer on a base material Any method can be used as long as it can form at least one laminate composed of the above.

  In the method for producing a near-infrared shielding film of the present invention, a high refractive index layer, a low refractive index layer, and a partition layer interposed between the high refractive index layer and the low refractive index layer are formed on the substrate. It is formed by laminating a laminate. Specifically, one of the low refractive index layer or the high refractive index layer, the partition layer, and the other of the low refractive index layer or the high refractive index layer is applied and dried. It is preferable to form a laminate. More specifically, the following forms may be mentioned: (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 partition layer coating solution is applied and dried. Forming a partition layer, and applying a low refractive index layer coating solution and drying to form a low refractive index layer to form a near infrared shielding film; (2) a low refractive index layer on a substrate; After applying the coating liquid and drying to form the low refractive index layer, coating the partition layer coating liquid and drying to form the partition layer, and applying and drying the high refractive index layer coating liquid to dry the high refractive index (3) A high refractive index layer coating solution, a partition layer coating solution, and a low refractive index layer coating solution were successively applied in layers to a substrate. Post-drying to form a near-infrared shielding film including a high refractive index layer, a low refractive index layer, and a partition layer interposed between the high refractive index layer and the low refractive index layer Method: (4) A high refractive index layer coating solution, a partition layer coating solution, and a low refractive index layer coating solution are simultaneously applied on a substrate, and dried to form a high refractive index layer and a low refractive index layer. And a method of forming a near infrared shielding film including a partition layer interposed between the high refractive index layer and the low refractive index layer. Among these, the method (4), which is a simpler manufacturing process, is preferable.

  Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or US Pat. Nos. 2,761,419 and 2,761,791. A slide bead coating method using an hopper, an extrusion coating method, or the like is preferably used.

  The solvent for preparing the high refractive index layer coating solution, the low refractive index layer coating solution, and the partition layer coating solution 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 water or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and more preferably water.

  The concentration of the first water-soluble binder resin in the high refractive index layer coating solution is preferably 1 to 10% by mass. Moreover, it is preferable that the density | concentration of the 1st metal oxide particle in a high refractive index layer coating liquid is 1-50 mass%.

  The concentration of the second water-soluble binder resin in the low refractive index layer coating solution is preferably 1 to 10% by mass. Moreover, it is preferable that the density | concentration of the 2nd metal oxide particle in a low refractive index layer coating liquid is 1-50 mass%.

  The method for preparing the high refractive index layer coating solution and the low refractive index layer coating solution is not particularly limited. For example, metal oxide particles, a binder resin, and other additives that are added as necessary are added and stirred. The method of mixing 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.

  The method for preparing the partition layer coating solution is not particularly limited as long as the third water-soluble binder resin is added as a resin component, and a small amount of metal oxide particles or other additives added as necessary are added. The method of stirring and mixing 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.

  In the present invention, it is preferable to form a high refractive index layer using an aqueous high refractive index coating solution prepared by adding and dispersing rutile type titanium oxide having a volume average particle size of 100 nm or less. At this time, as the rutile type titanium oxide, it is added to the high refractive index layer coating liquid as an aqueous titanium oxide sol having a pH of 1.0 or more and 3.0 or less and a positive zeta potential of the titanium particles. It is preferable to prepare.

  The viscosity of the high refractive index layer coating solution, the low refractive index layer coating solution, and the partition layer when performing simultaneous multilayer coating is preferably in the range of 5 mPa · s to 100 mPa · s when the slide bead coating method is used. More preferably, it is in the range of 10 mPa · s to 50 mPa · s. Moreover, when using a curtain application | coating system, the range of 5 mPa * s-1200 mPa * s is preferable, More preferably, it is the range of 25 mPa * s-500 mPa * s.

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

  As a coating and drying method, a high refractive index layer coating solution, a low refractive index layer coating solution, and a partition layer are heated to 30 ° C. or more and coated, and then the temperature of the formed coating film is set to 1 to 15. It is preferable that the temperature is once cooled to 10 ° C. and dried at 10 ° C. or higher. More preferably, the drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the formed coating-film uniformity.

{Near-infrared shield}
The second of the present invention is a near infrared shielding body in which the near infrared shielding film according to the present invention is provided on at least one surface of a substrate.
The near-infrared shielding film provided by the present invention can be applied to a wide range of fields. For example, film for window pasting such as near-infrared shielding film that provides near-infrared shielding effect, and pasting to facilities exposed to sunlight for a long time such as outdoor windows of buildings and automobile windows, for agricultural greenhouses It is used mainly for the purpose of improving weather resistance as a film or the like.

  In particular, the near-infrared shielding film according to the present invention is suitable for a member that is bonded to a substrate such as glass or a glass substitute resin directly or via an adhesive.

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

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

  As an 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.

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

  The heat insulation performance and solar heat shielding performance of the near-infrared shielding film or near-infrared reflector are generally JIS R 3209 (multi-layer glass), JIS R 3106 (transmittance, reflectance, emissivity, solar radiation of plate glass). Heat acquisition rate test method), and a method based on JIS R 3107 (calculation method of thermal resistance of plate glass and heat transmissivity in architecture).

  The solar transmittance, solar reflectance, emissivity, and visible light transmittance are measured by (1) using a spectrophotometer having a wavelength (300 nm to 2500 nm) to measure the spectral transmittance and spectral reflectance of various single plate glasses. Further, the emissivity is measured using a spectrophotometer having a wavelength of 5.5 μm 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 modified emissivity are calculated according to JIS R 3106 by calculating the solar transmittance, solar reflectance, solar absorption rate, and vertical emissivity. The corrected emissivity is obtained by multiplying the coefficient shown in JIS R 3107 by the vertical emissivity. 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 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 in accordance with JIS R 3107. (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) Solar heat shielding properties are calculated by obtaining the solar heat acquisition rate according to JIS R 3106 and subtracting from 1.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

{Preparation of near-infrared shielding film}
Example 1
<Preparation of near-infrared shielding film samples 102 to 105>
(Preparation of coating liquid L1 for low refractive index layer)
First, 21 parts of a 23.5% by weight aqueous solution of polyaluminum chloride (Takibine # 1500, manufactured by Taki Chemical), 550 parts of a 10% by weight aqueous solution of colloidal silica (Snowtex OXS, manufactured by Nissan Chemical Industries), 3.0 61 parts by weight of a boric acid aqueous solution of 61% and 4.75 parts of a 2.1% by weight aqueous lithium hydroxide solution were mixed and dispersed using a high-pressure homogenizer disperser. Then, pure water was added to prepare 1000 parts of silicon oxide dispersion L1 as a whole.

  Subsequently, the obtained dispersion L1 was heated to 45 ° C., and 100 parts of pure water and 575 parts of a 4.0% by mass aqueous solution of polyvinyl alcohol (PVA235, manufactured by Kuraray Co., Ltd.) were added thereto while stirring. Thereafter, 0.50 part of 5% by mass of a quaternary ammonium salt cationic surfactant (Nissan Cation-2-DB-500E manufactured by NOF Corporation) is added as a surfactant, and the coating liquid L1 for the low refractive index layer is added. Was prepared.

(Preparation of coating liquid H1 for high refractive index layer)
First, 28.9 parts of a titanium oxide sol aqueous dispersion containing 20.0% by mass of rutile-type titanium oxide fine particles (volume average particle diameter: 10 nm), 5.41 parts of a 14.8% by mass aqueous picolinic acid solution, 2 A titanium oxide dispersion H1 was prepared by mixing 3.92 parts of a 1% by mass lithium hydroxide aqueous solution.

  Subsequently, in 10.3 parts of pure water, 130 parts of a 1.0% by weight thickened polysaccharide tamarind seed gum aqueous solution, 5.0% by weight of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.) 10.3 parts, 14.8 17.3 parts of a mass% picolinic acid aqueous solution and 2.58 parts of a 5.5 mass% boric acid aqueous solution were sequentially added with stirring. Into this, 38.2 parts of the titanium oxide dispersion H1 obtained above was added. Thereafter, 0.050 part by weight of a quaternary ammonium salt-based cationic surfactant (Nissan Cation-2-DB-500E manufactured by NOF) was added as a surfactant. Pure water was added to prepare 223 parts of a coating solution H1 for a high refractive index layer as a whole.

(Preparation of partition layer coating solution M1)
150 parts of pure water, 10.3 parts of a 5.0% by weight polyvinyl alcohol (PVA217, manufactured by Kuraray) aqueous solution, 2.58 parts of a 5.5% by weight boric acid aqueous solution, and the silicon oxide dispersion obtained above Three parts of liquid L1 were added. Thereafter, pure water was added to prepare 223 parts of the partition layer coating solution M1 as a whole.

(Preparation of partition layer coating solution M2)
A partition layer coating solution M2 was prepared in the same manner as the partition layer coating solution M1, except that the silicon oxide dispersion L1 was not mixed.

(Preparation of partition layer coating solution M3)
The coating for the partition layer described above except that 10.3 parts of a 5.0% by mass polyethylene oxide (PEO-18, manufactured by Sumitomo Seika Chemical Co., Ltd.) aqueous solution was used instead of polyvinyl alcohol, and boric acid was not used. In the same manner as in the liquid M2, a partition layer coating liquid M3 was prepared.

(Preparation of partition layer coating solution M4)
The coating for the partition layer described above except that 10.3 parts of a 5.0% by mass polyethylene oxide (PEO-8, manufactured by Sumitomo Seika Co., Ltd.) aqueous solution was used instead of polyvinyl alcohol, and boric acid was not used. In the same manner as in the liquid M2, a partition layer coating liquid M3 was prepared.

“Preparation of Sample 102”
Using a stride hopper coating apparatus capable of 13-layer coating, the low refractive index layer coating liquid L1, the high refractive index layer coating liquid H1, and the partition layer coating liquid M1 are kept at 45 ° C. while maintaining the temperature at 45 ° C. On the polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm heated to ℃, the film thickness at the time of drying each of the high refractive index layer and the low refractive index layer is 150 nm. In addition, the lowest layer is a low refractive index layer so that the dry thickness of the partition layer is 35 nm, and the low refractive index layer and the high refractive index are in the order of low refractive index layer / partition layer / high refractive index layer / partition layer. The rate layer was 2 layers each and the partition layer was 3 layers, and a total of 7 layers were simultaneously applied.

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

  After completion of the setting, warm air of 80 ° C. was blown and dried to prepare a multilayer coating product consisting of 7 layers.

  On the 7-layer multi-layer coated product, a 7-layer multi-layer coating was further performed 6 times to prepare a sample 102 having a total of 49 layers.

"Production of sample 103"
A sample 103 was produced in the same manner as the sample 102 except that the partition layer coating solution M2 was used instead of the partition layer coating solution M1.

“Preparation of Sample 104”
A sample 104 was produced in the same manner as the sample 102 except that the partition layer coating solution M3 was used instead of the partition layer coating solution M1.

“Production of Sample 105”
A sample 105 was produced in the same manner as the sample 102 except that the partition layer coating solution M4 was used instead of the partition layer coating solution M1.

Comparative Example 1
<Preparation of near-infrared shielding film sample 101 (comparative)>
“Preparation of Sample 101”
Using a slide hopper coating apparatus capable of 13-layer coating, the above-mentioned low refractive index layer coating liquid L1 and high refractive index layer coating liquid H1 are heated to 45 ° C. while being heated to 45 ° C., and have a thickness of 50 μm. On the terephthalate film (Toyobo A4300, double-sided easy-adhesion layer), the bottom layer is the low-refractive index layer so that the thickness of each of the high-refractive index layer and the low-refractive index layer when dried is 150 nm. Then, simultaneous coating of 3 layers of low refractive index layers and 6 layers of 3 layers of high refractive index layers in total was performed.

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

  After completion of the setting, warm air of 80 ° C. was blown and dried to prepare a multilayer coating product consisting of 6 layers.

  On the six-layer multilayer coated product, six-layer multilayer coating was further performed three times to prepare a sample 101 having a total of 24 layers.

{Evaluation of near-infrared shielding film}
The following performance evaluation was performed about each near-infrared shielding film produced above.

<Measurement of single film refractive index of each layer>
Samples in which the target layers (high refractive index layer, low refractive index layer, and partition layer) for measuring the refractive index are coated as single layers on a substrate are prepared, and according to the following method, each high refractive index layer and The refractive index of the low refractive index layer was determined.

  A U-4000 type (manufactured by Hitachi, Ltd.) was used as a spectrophotometer. After roughening the measurement-side back surface of each sample, light absorption treatment is performed with a black spray to prevent reflection of light on the back surface, and the visible light region (400 nm to The refractive index was determined from the measurement result of the reflectance at 700 nm.

  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 was 0.1 or more. Furthermore, it was confirmed that the refractive index of the partition layer is not less than the refractive index of the high refractive index layer and not more than the refractive index of the low refractive index layer.

<Measurement of visible light transmittance and near infrared transmittance>
Using the spectrophotometer (using an integrating sphere, manufactured by Hitachi, Ltd., U-4000 type), the transmittance of the near-infrared shielding film samples 101 to 105 in the region of 300 nm to 2000 nm was measured. The transmittance value at 550 nm was used as the visible light transmittance, and the transmittance value at 1200 nm was used as the near infrared transmittance.

<Reflection glare evaluation>
The near-infrared shielding film samples 101 to 105 obtained above are each cut into a 20 cm square, the distance from the visual front to the film sample surface is kept at 10 cm, the film sample and the line of sight are perpendicular, and are held with both hands . Next, while maintaining the distance between the center of the surface of the film sample and the frontal view, the film sample is tilted by 30 ° in each of the vertical and horizontal directions from the line of sight to observe the reflected light. By this method, the rainbow-colored reflection glare on the surface of the film sample was visually evaluated, and the one with strong glare was set to 5, and a total of five stages of evaluation was performed.

<Temperature and humidity change durability evaluation>
The near-infrared shielding film samples 101 to 105 are placed in a high-temperature and high-humidity environment at a temperature of 40 ° C. and a humidity of 80% for 4 hours, and then changed to an environment of a temperature of 20 ° C. and a humidity of 50% over 2 hours. The temperature and humidity change durability test was conducted for a total of 6 cycles, with 1 cycle being left for 4 hours and then returning to a temperature of 40 ° C. and 80% over 2 hours. Thereafter, the visible light transmittance and the near-infrared transmittance were respectively obtained as the results after the durability evaluation in the same manner as described above. The results are shown in Table 1.

  From the results shown in Table 1, any of the near-infrared shielding film samples 102 to 105 of the present invention has no glare, high visible light transmittance and near-infrared shielding properties when compared with the comparative sample 101, Further, it can be seen that even after repeated temperature and humidity changes, the visible light transmittance is high and the near infrared transmittance is low, that is, the durability is excellent.

Example 2
{Production of near-infrared shield}
<Preparation of near-infrared shields 201-204>
The near-infrared shielding films of Samples 102 to 105 produced in Example 1 were each adhered to a transparent acrylic resin plate having a thickness of 5 mm and 20 cm × 20 cm with an acrylic adhesive, and the near-infrared shielding bodies 201 to 204 were bonded. Was made.

<Evaluation of near-infrared shield>
The near-infrared shields 201 to 204 of the present invention produced above can be easily used, and excellent near-infrared shielding properties are confirmed by using the near-infrared shield film of the present invention. I was able to.

  The present invention is suitable as a near-infrared shield.

Claims (9)

A substrate;
A high refractive index layer containing a first water-soluble binder resin and first metal oxide particles, a low refractive index layer containing a second water-soluble binder resin and second metal oxide particles, and the high refractive index layer And a laminate formed on the substrate with a partition layer interposed between the low refractive index layer and the low refractive index layer,
Have
The refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more.
Near-infrared shielding film.   2. The near-infrared shielding film according to claim 1, wherein a refractive index of the partition layer is equal to or lower than a refractive index of the high refractive index layer and equal to or higher than a refractive index of the low refractive index layer.   It is laminated | stacked from the said base material in order of one side of the said low refractive index layer or the said high refractive index layer, the said partition layer, and the other of the said low refractive index layer or the said high refractive index layer. Near infrared shielding film.   The near-infrared shielding film of any one of Claims 1-3 in which the said partition layer contains the resin component which consists only of 3rd water-soluble binder resin.   The near-infrared shielding film according to claim 4, wherein the third water-soluble binder resin does not have a reactive functional group that reacts with the first or second water-soluble binder resin.   The near-infrared shielding film according to claim 4 or 5, wherein the third water-soluble binder resin is a polyethylene oxide resin.   The near-infrared shielding film according to claim 1, wherein the partition layer has a thickness of 1 nm to 50 nm.   The near-infrared shielding according to any one of claims 1 to 7, wherein the first metal oxide particles are rutile titanium oxide particles, and the second metal oxide particles are silica particles. the film.   The near-infrared shielding body which provides the infrared shielding film of any one of Claims 1-8 in the at least one surface of a base | substrate.