JP2012230179A - Infrared shielding film, manufacturing method of infrared shielding film, and infrared shield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an infrared shielding film which reduces interlayer diffusion of metal oxide particles by using metal oxide particles and a water-soluble binder, maintains a high infrared reflectance, and has an excellent adhesiveness to glass or the like; a manufacturing method of it; and an infrared shield provided with the infrared shielding film.SOLUTION: An infrared shielding film comprises, on a substrate, at least one unit constituted by a high refractive index layer containing a first water-soluble polymer and first metal oxide particles, a low refractive index layer containing a second water-soluble polymer and second metal oxide particles, and an intermediate layer disposed in between the high refractive index layer and the low refractive index layer. The difference of refractive indexes of the high refractive index layer and the low refractive index layer is 0.1 or larger, and the elastic modulus of the intermediate layer is 2 to 100 times higher than the higher one of the elastic modulus of the high refractive index layer and the elastic modulus of the low refractive index layer.

Description

  The present invention relates to an infrared shielding film, a method for producing an infrared shielding film, and an infrared shielding body.

  In recent years, interest in energy conservation measures has increased, and from the viewpoint of reducing the load on cooling equipment, there has been an increasing demand for infrared shielding films that can be attached to window glass of buildings and vehicles to block the transmission of solar heat rays. It is coming.

  As a method for forming an infrared shielding film, a dry film forming method such as a vapor deposition method or a sputtering method is mainly used for a laminated film having a structure in which a high refractive index layer and a low refractive index layer are alternately laminated. A method of forming the above has been proposed. However, the dry film forming method has problems such as a large vacuum apparatus used for forming, high manufacturing cost, difficult to enlarge, and limited to a heat-resistant material as a base material. Yes.

  A method of forming an infrared shielding film using a wet coating method instead of the dry film forming method having the above-described problems is known.

  For example, only a low refractive index of a coating solution for a high refractive index layer in which a thermosetting silicone resin containing metal oxide or metal compound fine particles or an ultraviolet curable acrylic resin is dispersed in an organic solvent, and a resin to which no metal oxide particles are added. A method of applying a coating solution for a rate layer on a substrate by a wet coating method using a bar coater to form a transparent laminate (see, for example, Patent Document 1), titanium oxide, an ultraviolet curable binder, and an organic solvent A method for forming a transparent laminate by applying a composition for forming a high refractive index coating film composed of a low refractive index layer coating solution of hydroxyethyl cellulose on a substrate by a wet coating method using a spin coater ( For example, see Patent Document 2).

  On the other hand, a method of alternately laminating methanol dispersion slurry of spherical rutile-type titanium oxide particles and methanol silica sol (see, for example, Patent Document 3) is also disclosed.

JP-A-8-110401 JP 2009-86659 A Japanese Patent Laid-Open No. 2003-266577

  However, in the techniques described in Patent Documents 1 to 3, the formed film is too hard or the adhesion between the layers is insufficient, and when the film is strongly bent, delamination occurs. There was a problem that the adhesion of the shielding film to glass was insufficient.

  In order to solve these problems, a method of mixing metal oxide particles with a water-soluble binder and alternately laminating a high refractive index layer and a low refractive index layer is conceivable. Since the interlayer aggregation of the compound particles occurs, the unevenness at the interface between the high refractive index layer and the low refractive index layer and the film surface becomes large. As a result, as described above, there was a problem that delamination between the high refractive index layer and the low refractive index layer was likely to occur, and the adhesiveness of the infrared shielding film to glass was insufficient.

  In order to reduce the aggregation between particles, it is conceivable to reduce the amount of metal oxide particles or metal compound particles added. However, interlayer adhesion and adhesion to glass are still insufficient, and metal oxide particles are not sufficient. Due to the interlayer diffusion, a difference in refractive index between the high refractive index layer and the low refractive index layer is reduced, resulting in a problem that the infrared reflectance of the film is lowered.

  This invention is made | formed in view of the said subject, The objective is to reduce the interlayer spreading | diffusion of a metal oxide particle using a metal oxide particle and a water-soluble binder, and to maintain a high infrared reflectance. It is possible to provide an infrared shielding film excellent in adhesiveness with glass or the like, a method for producing the same, and an infrared shielding body provided with the infrared shielding film.

  The present inventors have conducted intensive studies in view of the above problems. As a result, surprisingly, an infrared shielding film having a high refractive index layer, a low refractive index layer, and an intermediate layer located between the high refractive index layer and the low refractive index layer, the amount of binder It is possible to maintain high infrared reflectivity by suppressing interlayer diffusion of metal oxide particles even if the amount is reduced, and delamination between the high refractive index layer and the low refractive index layer hardly occurs, and adhesion to glass or the like The present inventors have found that an infrared shielding film having excellent properties can be realized, and have completed the present invention.

  That is, the above object of the present invention is achieved by the following configuration.

  1. A high refractive index layer containing a first water-soluble polymer and first metal oxide particles on a substrate, and a low refractive index layer containing a second water-soluble polymer and second metal oxide particles, And at least one unit consisting of an intermediate layer located between the high refractive index layer and the low refractive index layer, and the refractive index difference between the high refractive index layer and the low refractive index layer is 0 Infrared shielding, wherein the elastic modulus of the intermediate layer is 2 to 100 times the higher one of the elastic modulus of the high refractive index layer and the elastic modulus of the low refractive index layer the film.

  2. The intermediate layer includes a gel formed of a polyvalent metal compound and a thickening polysaccharide. An infrared shielding film according to 1.

  3. The intermediate layer includes a gel formed from two different thickening polysaccharides. An infrared shielding film according to 1.

  4). A coating solution for a high refractive index layer containing the first water-soluble polymer, the first metal oxide particles, and the first compound, the second water-soluble polymer, the second metal oxide particles, and the first An infrared shielding film comprising a step of applying a coating solution for a low refractive index layer containing a compound of 2, wherein the first compound and the second compound react with each other to form a gel Manufacturing method.

  5). Above 1. ~ 3. 3. The infrared shielding film according to any one of 4) or 4 above. The infrared shielding body which provided the infrared shielding film obtained by the manufacturing method as described in 1 on the at least one surface of the base | substrate.

  According to the present invention, metal oxide particles and a water-soluble binder are used to reduce interlayer diffusion of metal oxide particles, and to reduce unevenness at the interface between the high refractive index layer and the low refractive index layer and the film surface. Infrared shielding film having high adhesion to glass and the like, and its manufacturing method, and infrared provided with the infrared shielding film A shield may be provided.

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

  Conventionally, as a method of forming an infrared shielding film by a wet coating method, for a high refractive index layer in which a thermosetting silicone resin containing a metal oxide or metal compound fine particles or an ultraviolet curable acrylic resin is dispersed in an organic solvent. A method for forming a transparent laminate by applying a coating solution onto a substrate by a wet coating method using a bar coater; a composition for forming a high refractive index coating film comprising titanium oxide, an ultraviolet curable binder and an organic solvent A method of forming a transparent laminate by applying a product onto a substrate by a wet coating method using a spin coater; a method of alternately laminating methanol dispersion slurry of spherical rutile type titanium oxide particles and methanol silica sol, etc. was there.

  However, in the manufacturing method described above, the formed film is too hard or the adhesion between the layers is insufficient, and when it is strongly bent, delamination occurs. There was a problem that the adhesiveness of the resin became insufficient.

  In order to solve these problems, a method of mixing metal oxide particles with a water-soluble binder and alternately laminating a high refractive index layer and a low refractive index layer is conceivable. Interfacial aggregation of compound particles occurs, resulting in large irregularities at the interface between the high refractive index layer and the low refractive index layer and the film surface. As a result, delamination occurs between the high refractive index layer and the low refractive index layer, resulting in red There were problems such as insufficient adhesion of the outer shielding film to the glass.

  In order to reduce the aggregation between particles, it is conceivable to reduce the amount of metal oxide particles or metal compound particles added. However, interlayer adhesion and adhesion to glass are still insufficient, and metal oxide particles are not sufficient. The interlayer diffusion of the film increases, and the difference in refractive index between the high-refractive index layer and the low-refractive index layer decreases, resulting in a problem that the infrared reflectance of the film decreases.

  In contrast, in the infrared shielding film of the present invention, between the high refractive index layer and the low refractive index layer, either the elastic modulus of the high refractive index layer or the elastic modulus of the low refractive index layer, whichever is higher, It has an intermediate layer having an elastic modulus of 100 times. As a result, even if the binder amount of the high refractive index layer and the low refractive index layer is reduced, that is, the amount of the metal oxide particles in the high refractive index layer and the low refractive index layer is increased, the interlayer diffusion of the metal oxide particles Can be suppressed, and a high infrared reflectance can be maintained. Moreover, the unevenness | corrugation in the interface of a high refractive index layer and a low-refractive-index layer and a film surface can be reduced, delamination between a high-refractive-index layer and a low-refractive-index layer does not occur easily, it is excellent in haze, and glass etc. An infrared shielding film having excellent adhesion can be obtained.

  Hereinafter, the components of the infrared shielding film of the present invention will be described in detail.

[Base material]
The substrate used in the infrared shielding film of the present invention is preferably a film support. The film support may be transparent or opaque, and various resin films can be used. Specific examples thereof include polyolefin films (polyethylene, polypropylene, etc.), polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose triacetate, etc., preferably polyester films. Although it does not specifically limit as a polyester film (henceforth polyester), It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components. The main constituent dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples thereof include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like. Among the polyesters having these as main constituent components, from the viewpoint of transparency, mechanical strength, dimensional stability, etc., dicarboxylic acid components such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components such as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Of these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymer polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

  The thickness of the substrate according to the present invention is preferably 10 to 300 μm, more preferably 20 to 150 μm. Two or more substrates may be stacked, and in this case, the types of the substrates may be the same or different.

[High refractive index layer]
The high refractive index layer according to the present invention includes a first water-soluble polymer and first metal oxide particles.

<First water-soluble polymer>
Examples of the first water-soluble polymer include, for example, a polymer containing a reactive functional group, gelatin, or thickening polysaccharide. These first water-soluble polymers may be used alone or in combination of two or more. The first water-soluble polymer may be a synthetic product or a commercially available product. Hereinafter, the first water-soluble polymer will be described in detail.

(Polymer having reactive functional group)
Examples of the polymer having a reactive functional group used in the present invention include polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate. -Acrylic resin such as acrylic acid ester copolymer or acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer Styrene-acrylate resins such as styrene-α-methylstyrene-acrylic acid copolymer, or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer, styrene- 2-hydroxyethyla Chryrate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene- Mention may be made of maleic acid copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-based copolymers such as vinyl acetate-acrylic acid copolymers, and salts thereof. Among these, polyvinyl alcohols, polyvinyl pyrrolidones, and copolymers thereof are preferable.

  The polyvinyl alcohol preferably used in the present invention includes, in addition to normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, cation-modified polyvinyl alcohol having a cation-modified terminal and anion-modified polyvinyl alcohol having an anionic group. Modified polyvinyl alcohol is also included.

  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%, more preferably 80 to 99.5%.

  As the cation-modified polyvinyl alcohol, for example, polyvinyl having a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain as described in JP-A-61-110483 Examples include alcohols, which can be 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 cationic group-containing ethylenically unsaturated monomer in the cation-modified polyvinyl alcohol is preferably 0.1 to 10 mol%, more preferably 0.2 to 5 mol% with respect to vinyl acetate.

  Anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681 and JP-A-63-330779. Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, or 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. Examples thereof include a block copolymer of a vinyl compound having a hydrophobic group as described and vinyl alcohol. Polyvinyl alcohol can be used in combination of two or more kinds having different degrees of polymerization and modification.

  The form of the copolymer when the polymer having the reactive functional group is a copolymer may be any of a block copolymer, a random copolymer, a graft copolymer, and an alternating copolymer. Good.

(gelatin)
Examples of gelatin used in the present invention include various types of gelatin that have been widely used in the field of silver halide photographic materials. For example, in addition to acid-treated gelatin and alkali-treated gelatin, enzyme-treated gelatin and gelatin derivatives that undergo enzyme treatment in the gelatin production process, that is, amino, imino, hydroxyl, or carboxyl groups as functional groups in the molecule It may be modified by treating with a reagent having a group obtained by reacting with it. The general method for producing gelatin is well known and is described, for example, in T.W. H. James: The Theory of Photographic Process 4th. ed. Reference can be made to the descriptions of 1977 (Machillan), p. 55, Science Photo Handbook (above), p. 72-75 (Maruzen), Fundamentals of Photographic Engineering-Silver Salt Photography, p. 119-124 (Corona). Also, Research Disclosure Magazine Vol. 176, No. The gelatin described in IX page of 17643 (December, 1978) can be mentioned.

(Thickening polysaccharide)
The thickening polysaccharide 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. For details of these thickening polysaccharides, reference can be made to “Biochemical Dictionary (2nd edition)” (Tokyo Kagaku Dojin), “Food Industry”, Vol. 31 (1988), p.

  The thickening polysaccharide is a polymer of saccharides and has a large number of hydrogen bonding groups in the molecule. Due to the difference in hydrogen bonding strength between molecules depending on the temperature, the viscosity at low temperature and the viscosity at high temperature are different. It is a polysaccharide with the characteristic that the difference is large, and when metal oxide particles or polyvalent metal compounds are added, the metal oxide particles or polyvalent metals react with the metal oxide particles or polyvalent metal compounds at low temperatures. It forms a hydrogen bond or ionic bond with the compound, causing an increase in viscosity or gelation. The increase in viscosity is preferably 1.0 mPa · s or more at 15 ° C. compared to the viscosity at 15 ° C. before the addition of the metal oxide particles or the polyvalent metal compound. The viscosity increase width is more preferably 5.0 mPa · s or more, and further preferably 10.0 mPa · s or more. In this specification, a value measured with a Brookfield viscometer is adopted as the viscosity.

  More specific examples of thickening polysaccharides applicable to the present invention include, for example, pectin, galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum, guaran, etc.), xyloglucan, etc. (Eg, tamarind gum, tamarind seed gum, etc.), glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabinogalactoglycan ( For example, soybean-derived glycans, microbial-derived glycans, etc.), glucoraminoglycans (eg, gellan gum), glycosaminoglycans (eg, hyaluronic acid, keratan sulfate, etc.), alginic acid and alginate, agar, κ-carrageenan, λ -Carrageenan, ι Carrageenan, natural polymer polysaccharides derived from red algae such as furcelleran, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose such as methyl cellulose. From the viewpoint of not lowering the dispersion stability of the metal oxide particles coexisting in the coating solution, it is preferable that the structural unit does not have a carboxylic acid group or a 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.

  Among the first water-soluble polymers described above, polyvinyl alcohol, gelatin, pectin are used from the viewpoint of easy protection of metal oxide particles and metal compound particles, and an intermediate layer having a high elastic modulus, and coating stability. At least one selected from the group consisting of locust bean gum, xanthan gum, carrageenan, gellan gum, alginic acid, and carboxymethylcellulose.

  The weight average molecular weight of the first water-soluble polymer is preferably 1,000 to 200,000, and more preferably 3,000 to 40,000. In the present specification, a value measured by gel permeation chromatography (GPC) is adopted as the weight average molecular weight.

  The content of the first water-soluble polymer in the high refractive index layer is preferably 3.0 to 60.0 mass% with respect to the total mass of the high refractive index layer, and is 8.0 to 35.0 mass%. % Is more preferable.

(Curing agent)
In the present invention, a curing agent can be used to cure the water-soluble polymer which is a binder.

  The curing agent applicable to the present invention is not particularly limited as long as it causes a curing reaction with a water-soluble polymer. However, when the water-soluble polymer is polyvinyl alcohol, boric acid and a salt thereof are preferable. Other known compounds can also be used, and are generally compounds having groups capable of reacting with water-soluble polymers, or compounds that promote the reaction between different groups of water-soluble polymers. It is appropriately selected according to the type of polymer. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-dibutanediol diglycidyl ether, 1,6-diglycidyl cyclohexane. N, N-diglycidyl-4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde-based curing agents (formaldehyde, glyoxal, etc.), active halogen-based curing Agents (2,4-dichloro-4-hydroxy-1,3,5-S-triazine, etc.), active vinyl compounds (1.3.5-tris-acryloyl-hexahydro-S-triazine, bisvinylsulfonylmethyl ester) -Tell etc.), aluminum alum and the like.

  When gelatin is used as the water-soluble polymer, examples of the hardener include vinyl sulfone compounds, urea-formalin condensates, melanin-formalin condensates, epoxy compounds, aziridine compounds, active olefins, isocyanates. It is preferable to use organic hardeners such as organic compounds, inorganic polyvalent metal salts such as chromium, aluminum and zirconium.

<First metal oxide particles>
As the first metal oxide particles contained in the high refractive index layer, metal oxide particles having a refractive index of 2.0 or more are preferable. More specifically, examples include zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), and zinc oxide (ZnO). Among these, titanium oxide (TiO ₂ ) is more preferable from the viewpoint of the stability of the coating liquid for forming the high refractive index layer. Of TiO ₂ , rutile type is more preferable than anatase type because the high refractive index layer and the adjacent layer have high weather resistance due to low catalytic activity, and the refractive index becomes higher.

  The average particle diameter of the first metal oxide particles is preferably 2 to 100 nm, more preferably 3 to 90 nm, and further preferably 4 to 80 nm.

  The average particle diameter of the first metal oxide particles was 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, measuring the particle diameter of 1,000 arbitrary particles, It is 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.

  Hereinafter, particularly preferable rutile type titanium oxide will be described in detail as the first metal oxide particles.

(Rutile titanium oxide)
In general, titanium oxide particles are often used in a surface-treated state for the purpose of suppressing photocatalytic activity on the particle surface and improving dispersibility in a solvent or the like. For example, titanium oxide particles Known are those in which the surface is covered with a coating layer made of silica and the particle surface is negatively charged, and in which the coating layer made of aluminum oxide is formed and the surface is positively charged at pH 8-10. .

  In the present invention, the metal oxide particles are preferably rutile (tetragonal) titanium oxide particles having a volume average particle diameter of 2 to 100 nm. The volume average particle diameter is more preferably 3 to 90 nm, and further preferably 4 to 80 nm. When the volume average particle size is 2 to 100 nm, the haze is low and the visible light transmittance is excellent.

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

More specifically, the volume average particle size of rutile-type titanium oxide 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, the _{d 1, d 2 ··· d i} ··· d each particle _n 1 having a particle size of _{k, n 2 ··· n i ···} n k pieces existing metal oxide particles respectively In the group, when the surface area per particle is a _i and the volume is v _i , the average particle diameter is obtained by weighting with the volume represented by the following formula 1.

  Furthermore, the rutile titanium oxide particles are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula 2 is 40% or less. More preferably, it is 30% or less, More preferably, it is 0.1 to 20%.

  In the present invention, the aqueous high-refractive index layer coating liquid used for producing the infrared shielding film has a pH of 1.0 to 3.0 as rutile titanium oxide, and zeta of titanium particles. It is preferable to include an aqueous titanium oxide sol having a positive potential.

  In general, titanium oxide particles are often used in a state in which surface treatment is performed for the purpose of suppressing photocatalytic activity on the particle surface or improving dispersibility in a solvent or the like. It is known that the particle surface is covered with a coating layer made of silica and the surface of the particle is negatively charged, or the surface of the particle is positively charged at pH 8 to 10 where the coating layer made of aluminum oxide is formed. In the present invention, it is preferable to use an aqueous sol of titanium oxide which has a pH of 1.0 to 3.0 and has a positive zeta potential and is not subjected to such surface treatment.

  As the rutile titanium oxide, a synthetic product or a commercially available product may be used. Examples of the method for producing rutile type titanium oxide include, for example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, JP-A-63-3. Reference can be made to the methods described in JP-A-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, and the like.

  As for other production methods of rutile type titanium oxide, for example, “Titanium oxide—physical properties and applied technology”, Manabu Seino, p. 255-258 (2000), Gihodo Publishing Co., Ltd. The method of the step (2) described in the paragraph numbers “0011” to “0023” of FIG.

  The content of the first metal oxide particles in the high refractive index layer is preferably 40 to 97% by mass and more preferably 60 to 90% by mass with respect to the total mass of the high refractive index layer.

  The thickness per layer of the high refractive index layer (thickness after drying) is preferably 20 to 1000 nm, and more preferably 50 to 500 nm.

  The refractive index of the high refractive index layer is preferably 1.70 to 2.50, more preferably 1.80 to 2.20.

  In addition, the refractive index of a high refractive index layer and the low refractive index layer mentioned later can be calculated | required by the method as described in the below-mentioned Example.

[Low refractive index layer]
The low refractive index layer according to the present invention includes a second water-soluble polymer and second metal oxide particles.

<Second water-soluble polymer>
Specific examples of the second water-soluble polymer, preferred weight average molecular weight, and curing agent of the second water-soluble polymer are the same as those described in the column of the first water-soluble polymer, The description is omitted here.

  However, it is important to select a combination of the first water-soluble polymer and the second water-soluble polymer from the viewpoint of efficiently forming an intermediate layer described later. This will be described in detail later.

  The content of the second water-soluble polymer in the low refractive index layer is preferably 3 to 60% by mass and more preferably 10 to 45% by mass with respect to the total mass of the low refractive index layer. .

<Second metal oxide particles>
Specific examples of the second metal oxide particles include synthetic amorphous silica and colloidal silica.

  The second metal oxide particles preferably have an average particle size of 2 to 100 nm, more preferably 3 to 50 nm, and still more preferably 4 to 30 nm.

  The average particle size of the second metal oxide 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, measuring the particle size of 1,000 arbitrary particles, It is 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.

  Particularly preferably used colloidal silica 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 JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142, In JP-A-7-179029, JP-A-7-137431, and WO94 / 26530 pamphlet, etc. Are those mounting.

  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 preferred average particle size of colloidal silica is usually 3 to 50 nm, but an average particle size of 4 to 30 nm is particularly preferable.

  The content of the second metal oxide particles in the low refractive index layer is preferably 40 to 97% by mass and more preferably 60 to 90% by mass with respect to the total mass of the low refractive index layer. .

  The thickness per layer of the low refractive index layer (thickness after drying) is preferably 20 to 800 nm, and more preferably 50 to 350 nm.

  The refractive index of the low refractive index layer is preferably 1.10 to 1.60, more preferably 1.30 to 1.55.

[Refractive index difference]
In general, in an infrared shielding film, it is preferable to design a large difference in refractive index between a high refractive index layer and a low refractive index layer from the viewpoint of increasing the infrared reflectance with a small number of layers. In the present invention, the refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more, preferably 0.3 or more, more preferably 0.4 or more.

  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 refractive index difference, the higher the reflectance with a smaller number of layers. It is done. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain an infrared reflectance of 90% or more, if the refractive index difference is smaller than 0.1, it is necessary to laminate more than 100 layers, which not only lowers productivity but also scatters at the lamination interface. Increases and transparency decreases. From the viewpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but the limit is substantially about 1.40.

[Additive]
Various additives can be added to the high refractive index layer and the low refractive index layer according to the present invention as necessary. Hereinafter, the additive will be described.

<Amino acids with an isoelectric point of 6.5 or less>
In the present invention, the high refractive index layer or the low refractive index layer may further 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.

  Here, the amino acid means 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-, γ-, but has an isoelectric point of 6.5 or less. It is preferable that they are amino acids. 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 the amino acids according to the present invention, reference can be made to the description on pages 268 to 270 of the Chemical Dictionary 1 Reprint (Kyoritsu Shuppan; issued in 1960).

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

  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. In the present invention, it is preferable to use an amino acid having an isoelectric point of 6.5 or less. The isoelectric point of each amino acid can be determined by isoelectric focusing at a low ionic strength.

<Emulsion resin>
In the present invention, the high refractive index layer or the low refractive index layer 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.

  Here, the emulsion resin is a resin (preferably resin fine particles) obtained by emulsion-polymerizing an oil-soluble monomer in an aqueous solution containing a dispersant and using a polymerization initiator.

  Examples of the dispersant used in the polymerization of the emulsion include polyoxyethylene nonyl phenyl ether, in addition to low molecular weight dispersants such as alkyl sulfonate, alkyl benzene sulfonate, diethylamine, ethylenediamine, and quaternary ammonium salt. Examples thereof include polymer dispersants such as polyethylene ethylene laurate, hydroxyethyl cellulose, and polyvinyl pyrrolidone.

  The emulsion resin used in the present invention is preferably a resin in which fine, for example, resin particles having an average particle diameter of about 0.01 to 2.0 μm are dispersed in an emulsion state in an aqueous medium, and an oil-soluble monomer is used. It can be obtained by emulsion polymerization using a polymer dispersant having a hydroxyl group. There is no fundamental difference in the polymer component of the resulting emulsion resin depending on the type of dispersant used, but when emulsion polymerization is performed using a polymer dispersant having a hydroxyl group, the presence of hydroxyl groups is present on at least the surface of fine particles. It is presumed that the chemical and physical properties of the emulsion differ from the emulsion resin polymerized using other dispersants.

  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.

<Other additives>
Various additives applicable to the high refractive index layer and the low refractive index layer according to the present invention are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, and JP-A-57-87989. , JP-A-60-72785, JP-A-61-14659, JP-A-1-95091, JP-A-3-13376, etc. Nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, and JP-A-4-219266 Fluorescent brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, etc. Agents, lubricants such as diethylene glycol, preservatives, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, thickeners, lubricants, infrared rays Examples include various known additives such as absorbents, dyes, and pigments.

[Middle layer]
In the infrared shielding film of the present invention, between the high refractive index layer and the low refractive index layer, the elastic modulus of the higher refractive index layer or the low refractive index layer, whichever is higher, is 2-100. An intermediate layer having a modulus that is twice as high is provided. By providing such an intermediate layer, even if the binder amount of the high refractive index layer and the low refractive index layer is reduced, that is, the amount of metal oxide particles of the high refractive index layer and the low refractive index layer is increased, Interlayer diffusion of metal oxide particles can be suppressed, and high infrared reflectance can be maintained. In addition, the presence of the intermediate layer makes it possible to obtain an infrared shielding film that is less likely to cause delamination between the high refractive index layer and the low refractive index layer and has excellent haze and excellent adhesion to glass or the like.

  The configuration of the intermediate layer is not particularly limited, but preferably includes a gel formed from a polyvalent metal compound and a thickening polysaccharide, or a gel formed from two different types of thickening polysaccharides. In such a configuration, a compound that forms a gel by reacting with each other between the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is added, and after the completion of these coating solutions, the intermediate is formed in a short time. A layer can be formed, and the infrared shielding film of the present invention can be obtained by a simpler method.

  Here, the intermediate layer according to the present invention refers to the metal oxide based on the higher one of the amount of metal oxide particles contained in the high refractive index layer and the amount of metal oxide particles contained in the low refractive index layer. The amount of the kind of the object and the amount of the standard metal oxide means a region in which 10 to 50% by mass of the material of the standard type is included with respect to the amount of the standard.

  As a method for specifying the amount of metal oxide particles in the film thickness direction of each layer constituting the infrared shielding film of the present invention, for example, a laminated film is cut and the cut surface is energized with a scanning electron microscope (SEM). Etching from the surface of the layer to the film thickness direction using a method incorporating a dispersion X-ray spectroscopic detector (EDX) or sputtering, and 0.5 nm from the surface of the layer using an XPS surface analyzer A method of measuring while sputtering at a rate of / min.

  The EDX analyzer is not particularly limited, and examples thereof include an apparatus in which EDX Apollo 40 manufactured by EDAX is mounted on a scanning electron microscope S-4800 manufactured by Hitachi, Ltd. In addition, the XPS surface analyzer is not particularly limited, and any model can be used. Examples thereof include ESCALAB-200R manufactured by VG Scientific. When this XPS surface analyzer is used, for example, Mg can be used for the X-ray anode and measurement can be performed under conditions of an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA).

  The method for forming the intermediate layer is not particularly limited, but (A) the coating solution for the high refractive index layer contains the polyvalent metal compound, and the coating solution for the low refractive index layer contains the thickening polysaccharide. A method of forming an intermediate layer after applying the coating liquid for coating and the coating liquid for low refractive index layer; (B) the coating liquid for high refractive index layer is a thickening polysaccharide, and the coating liquid for low refractive index layer is a polyvalent metal. A method of forming an intermediate layer after coating each of the compounds and applying a coating solution for a high refractive index layer and a coating solution for a low refractive index layer; (C) a coating solution for a high refractive index layer and a coating solution for a low refractive index layer; And a method of forming an intermediate layer after applying a coating solution for a high refractive index layer and a coating solution for a low refractive index layer, which include two different types of thickening polysaccharides. Details of the method of forming the intermediate layer will be described later.

Examples of the polyvalent metal compound forming the gel contained in the intermediate layer include sulfates, nitrates, acetates, halides such as Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Zr ²⁺ , Ni ²⁺ , or Al ³⁺ , or A hydroxide etc. are mentioned. These polyvalent metal compounds may be used alone or in combination of two or more.

  A specific example of the thickening polysaccharide that reacts with the polyvalent metal compound to form a gel is the same as the thickening polysaccharide described in the column of the high refractive index layer, and thus the description thereof is omitted here. These thickening polysaccharides may be used alone or in combination of two or more. Among these, gellan gum, alginic acid, pectin, or carboxymethylcellulose is more preferable from the viewpoint that a gel with a high elastic modulus can be obtained by reacting with a polyvalent metal.

  A preferred combination of two different thickening polysaccharides forming a gel is a combination of locust bean gum and at least one selected from the group consisting of xanthan gum, carrageenan, and gellan gum.

  The elastic modulus of the intermediate layer is 2 to 100 times higher, preferably 3 to 50 times higher than the higher one of the elastic modulus of the high refractive index layer and the elastic modulus of the low refractive index layer. Within such an elastic modulus range, it is possible to reduce the diffusion of the metal oxide particles of the high refractive index layer and the metal oxide particles of the low refractive index layer from the respective layers, resulting in refraction. The difference in rate increases, and an infrared shielding film having a high infrared reflectance can be obtained even with a small number of layers. Moreover, the unevenness | corrugation in the interface of a high refractive index layer and a low refractive index layer and film surface by aggregation of a metal oxide particle can be reduced, and it becomes an infrared shielding film with high adhesiveness with glass etc. The elastic modulus can be obtained by a conventionally known elastic modulus measuring method. For example, using Vibron DDV-2 manufactured by Orientec Co., Ltd., a method for measuring under a condition in which a constant strain is applied at a constant frequency (Hz), using RSA-II (Rheometrics) as a measuring device From the method of obtaining by changing the applied strain at a constant frequency after forming a layer on the material, or from the load-displacement curve obtained by continuously loading and unloading the indenter with a very small load on the sample It can be measured by a nanoindentation method for obtaining an elastic modulus.

  The thickness per layer of the intermediate layer is preferably 1 to 50 nm, and more preferably 5 to 20 nm. In addition, the thickness of an intermediate | middle layer can be measured with the measuring method as described in the below-mentioned Example.

  In the infrared shielding film of this invention which has such an intermediate | middle layer, content of the metal oxide particle in a high refractive index layer and a low refractive index layer can be made higher than the conventional infrared shielding film. . As a result, the refractive index difference between the high refractive index layer and the low refractive index layer can be increased, and a high infrared reflectance can be obtained with a smaller number of layers. Specifically, the mass ratio between the first metal oxide particles (F: filler) and the first water-soluble polymer (B: binder) in the high refractive index layer is preferably F / B = 1 /. 1 to 20/1, more preferably F / B = 2/1 to 10/1. Similarly, the mass ratio between the second metal oxide particles (F: filler) and the second water-soluble polymer (B: binder) in the low refractive index layer is preferably F / B = 1 / 1˜. 20/1, more preferably F / B = 2/1 to 10/1.

  The infrared shielding film of the present invention has at least one unit composed of a high refractive index layer, a low refractive index layer, and an intermediate layer located between the high refractive index layer and the low refractive index layer. In the case of having two or more units, the intermediate layer may or may not be provided between the units. Preferably, an intermediate layer is provided between the units.

[Infrared shielding film]
The infrared shielding film of the present invention comprises at least one unit comprising a high refractive index layer, a low refractive index layer, and an intermediate layer located between the high refractive index layer and the low refractive index layer on a substrate. One feature is that a difference in refractive index between the high refractive index layer and the low refractive index layer is 0.1 or more. Furthermore, as an optical characteristic of the infrared shielding film of the present invention, the transmittance in the visible light region measured by JIS R3106-1998 is 50% or more, and the reflectance is 50% in the wavelength region of 900 nm to 1400 nm. It is preferable to have a region that exceeds.

  The infrared shielding film of the present invention may have a constitution having at least one unit composed of a high refractive index layer, a low refractive index layer and an intermediate layer on the substrate. The upper limit of the total number of layers is preferably 100 layers or less, that is, 50 units or less, more preferably 40 layers (20 units) or less, and even more preferably 20 layers (10 units) or less.

  The total thickness of the 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. Thus, the infrared shielding film of the present invention can obtain a high infrared reflectance with a thinner film thickness than the conventional infrared shielding film.

  The infrared shielding film of the present invention has a conductive layer, an antistatic layer, a gas barrier layer, an easy-adhesion layer (for the purpose of adding further functions under the base material or on the outermost surface layer opposite to the base material). Adhesive layer), antifouling layer, deodorant layer, droplet layer, slippery layer, hard coat layer, wear-resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorption layer, infrared absorption layer, printing layer, fluorescence emission Layer, hologram layer, release layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer) other than the high refractive index layer and low refractive index layer of the present invention, colored layer (visible light absorbing layer), laminated glass It may have one or more functional layers such as an intermediate film layer used in the above.

[Infrared shielding film manufacturing method]
Although the manufacturing method of the infrared shielding film of this invention is not restrict | limited in particular, For a high refractive index layer containing a 1st water-soluble polymer, a 1st metal oxide particle, and a 1st compound on a base material. A production method including a step of applying a coating solution and a coating solution for a low refractive index layer containing the second water-soluble polymer, the second metal oxide particles, and the second compound is preferable.

  More specifically, for example, (1) a high-refractive-index layer coating solution containing the first water-soluble polymer, the first metal oxide particles, and the first compound is applied onto the substrate and dried. After forming the high refractive index layer, a low refractive index layer coating liquid containing the second water-soluble polymer, the second metal oxide particles, and the second compound is applied and dried. Forming a layer and an intermediate layer to form an infrared shielding film; (2) low refraction comprising a second water-soluble polymer, second metal oxide particles, and a second compound on a substrate; After applying the coating liquid for the refractive index layer and drying to form the low refractive index layer, the coating liquid for the high refractive index layer containing the first water-soluble polymer, the first metal oxide particles, and the first compound. And drying to form an infrared shielding film by forming a high refractive index layer and an intermediate layer; (3) a first water-soluble high content on a substrate; , A coating solution for a high refractive index layer containing the first metal oxide particles and the first compound, and a low refractive index containing the second water-soluble polymer, the second metal oxide particles and the second compound. A method of forming an infrared shielding film including a high refractive index layer, a low refractive index layer, and an intermediate layer; (4) first water-soluble A coating solution for a high refractive index layer containing a polymer, first metal oxide particles, and a first compound, and a second water-soluble polymer, second metal oxide particles, and a second compound And a method of forming an infrared shielding film including a high refractive index layer, a low refractive index layer, and an intermediate layer by simultaneous multilayer coating with a coating solution for a low refractive index layer and drying. Among these, the method (4), which is a simpler manufacturing process, is preferable.

  The first compound and the second compound are compounds that react with each other to form a gel and form an intermediate layer. As the specific form thereof, as described in the section of the intermediate layer, (a) a form in which the first compound is a polyvalent metal compound and the second compound is a thickening polysaccharide; ) A form in which the first compound is a thickening polysaccharide and the second compound is a polyvalent metal compound; (c) two types of thickening in which the first compound and the second compound are different from each other; The form which is a polysaccharide; etc. are mentioned. Among these, from the viewpoint of storage stability of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer, the form (a) or (c) is preferable.

  Furthermore, in the case of the form (c), the thickening polysaccharide used as the first compound can serve as a binder for the high refractive index layer, and is used as the second compound. The thickening polysaccharide can serve as a binder for the low refractive index layer. Therefore, in the case of the form (c), the separate first water-soluble polymer and the separate second water-soluble polymer may or may not be used.

  The coating method is not particularly limited, and for example, roll coating method, rod bar coating method, air knife coating method, spray coating method, slide curtain coating method, or U.S. Pat. No. 2,761,419, U.S. Pat. Examples thereof include a slide hopper coating method and an extrusion coating method described in Japanese Patent No. 2,761,791.

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

<Solvent>
The solvent for preparing the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable.

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

  From the viewpoint of environment and simplicity of operation, the solvent for the coating solution is particularly preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate.

<Concentration of coating solution>
The concentration of the first water-soluble polymer in the coating solution for the high refractive index layer is preferably 1 to 10% by mass. Moreover, it is preferable that the density | concentration of the 1st metal oxide particle in the coating liquid for high refractive index layers is 2-50 mass%.

  The concentration of the first water-soluble polymer in the coating solution for the low refractive index layer is preferably 1 to 10% by mass. Moreover, it is preferable that the density | concentration of the 1st metal oxide particle in the coating liquid for high refractive index layers is 2-50 mass%.

  Further, the mass ratio (F / B) between the metal oxide particles and the water-soluble polymer in the coating solution for the high refractive index layer and the coating solution for the low refractive index layer falls within the numerical range described in the column for the intermediate layer. Thus, it is preferable to add metal oxide particles and a water-soluble polymer to the coating solution.

  The concentration of the first compound contained in the coating solution for the high refractive index layer in the coating solution and the concentration of the second compound contained in the coating solution for the low refractive index layer are the first compound and the second compound. Depending on the type of the compound, it may be appropriately selected. For example, taking the form (a), which is a preferred form among the above (a) to (c), as an example, the concentration of the polyvalent metal compound that is the first compound contained in the coating solution for the high refractive index layer is It is preferable that it is 0.005-0.1 mass%, and the density | concentration of the thickening polysaccharide which is a 2nd compound contained in the coating liquid for low refractive index layers is 0.05-0.5 mass%. Is preferred.

<Method for preparing coating solution>
The method for preparing the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer is not particularly limited. For example, the water-soluble polymer, the metal oxide particles, the first compound, the second compound, and as necessary There may be mentioned a method in which other additives added in accordance with the above are added and mixed by stirring. At this time, the order of addition of the water-soluble polymer, the metal oxide particles, the first compound, the second compound, and other additives used as necessary is not particularly limited, and each component is sequentially added while stirring. It may be added and mixed, or may be added and mixed at a time while stirring. If necessary, it is further adjusted to an appropriate viscosity using a solvent.

<Viscosity of coating liquid>
The viscosity at 40 ° C. of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer when performing simultaneous multilayer coating by the slide hopper coating method is preferably in the range of 5 to 100 mPa · s, and is preferably 10 to 50 mPa · s. A range is more preferred. The viscosity at 40 ° C. of the coating solution for high refractive index layer and the coating solution for low refractive index layer at the time of simultaneous multilayer coating by the slide curtain coating method is preferably in the range of 5 to 1200 mPa · s, and 25 to 500 mPa · s. -The range of s is more preferable.

  Further, the viscosity at 15 ° C. of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, and more preferably 3,000 to 30,000 mPa · s. s is more preferable, and 10,000 to 30,000 mPa · s is particularly preferable.

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

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

  Here, the set refers to increasing the viscosity of the coating composition by reducing the temperature by applying cold air or the like to the coating film, or lowering the fluidity of each layer and the substance in each layer, or first And a second compound are reacted to form a gel, that is, to form an intermediate layer. A state in which the cold air is applied to the coating film from the surface and the finger is pressed against the surface of the coating film is defined as a set completion state.

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

  The set time can be adjusted by adjusting the concentration of water-soluble polymer and metal oxide particles, and adding other components such as gelatin, pectin, agar, carrageenan, gellan gum and other known gelling agents. It can be adjusted by doing.

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

[Infrared shield]
The infrared shielding film of the present invention can be applied to a wide range of fields. For example, as a film for window pasting such as heat ray reflective film that gives heat ray reflection effect, film for agricultural greenhouses, etc. It is mainly used for the purpose of improving weather resistance.

  Especially the infrared shielding film which concerns on this invention is used suitably for the member bonded by base | substrates, such as glass or glass substitute resin, directly or through an adhesive agent.

  That is, this invention also provides the infrared shielding body which provided the infrared shielding film of this invention, or the infrared shielding film obtained by the manufacturing method of this invention in the at least one surface of the base | substrate.

  Specific examples of the substrate include, for example, glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, melamine resin, Examples thereof include phenol resin, diallyl phthalate resin, polyimide resin, urethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, vinyl chloride resin, metal plate, ceramic and the like. The type of resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and two or more of these may be used in combination. The substrate that can be used in the present invention can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding and the like.

  The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

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

  Examples of the adhesive or pressure-sensitive adhesive applicable to the present invention include an adhesive or pressure-sensitive adhesive mainly composed of a photocurable or thermosetting resin.

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

  Moreover, you may use the polyvinyl butyral type resin used as an intermediate | middle layer of a laminated glass, or ethylene-vinyl acetate copolymer type resin as said adhesive agent or adhesive. Specific examples thereof include, for example, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont, manufactured by Takeda Pharmaceutical Company Limited, duramin), and modified ethylene-acetic acid. Vinyl copolymer (manufactured by Tosoh Corporation, Mersen G). In the adhesive layer or the adhesive layer, an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, a colorant, an adhesion (adhesion) adjusting agent, and the like may be appropriately added and blended.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to these Examples at all. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.

<Preparation of coating solution 1 for high refractive index layer>
0.47 g of calcium chloride anhydride (CaCl ₂ ) was added to 475 g of a 5.0% by mass low molecular weight gelatin (weight average molecular weight: 16000) aqueous solution, and the mixture was stirred and mixed to dissolve. 243.4 g of a 20.5 mass% titanium oxide sol (volume average particle size 35 nm, rutile type titanium oxide particles) was gradually added to the obtained solution while stirring and mixed. Next, 0.81 g of 5.0% by mass of 2-DB-500E (manufactured by NOF Corporation) is added as a surfactant, and pure water is added to make the total mass 1000 g, thereby increasing the refractive index. Layer coating solution 1 was prepared.

<Preparation of coating solution 2 for high refractive index layer>
A coating solution 2 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that locust bean gum was used instead of low molecular weight gelatin and CaCl ₂ was not added.

<Preparation of coating solution 3 for high refractive index layer>
A coating solution 3 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer, except that 0.47 g of magnesium hydroxide was used instead of calcium chloride anhydride.

<Preparation of coating solution 4 for high refractive index layer>
A coating solution 4 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer, except that 0.47 g of aluminum chloride was used instead of calcium chloride anhydride.

<Preparation of coating solution 5 for high refractive index layer>
Except that the amount of the 5.0% by mass low molecular weight gelatin aqueous solution was 475 g and the amount of the 20.5% by mass titanium oxide sol was 110.1 g, the same as the coating solution 1 for the high refractive index layer, A coating solution 5 for a high refractive index layer was prepared.

<Preparation of coating solution 6 for high refractive index layer>
Except that the amount of the 5.0% by mass low molecular weight gelatin aqueous solution was 475 g and the amount of the 20.5% by mass titanium oxide sol was 115.9 g, the same as the coating solution 1 for high refractive index layer, A coating solution 6 for a high refractive index layer was prepared.

<Preparation of coating solution 7 for high refractive index layer>
Except that the amount of the 5.0% by mass low molecular weight gelatin aqueous solution was 220 g and the amount of the 20.5% by mass titanium oxide sol was 536.6 g, the same as the coating solution 1 for high refractive index layer, A coating solution 7 for a high refractive index layer was prepared.

<Preparation of coating solution 8 for high refractive index layer>
Except that the amount of the 5.0% by mass low molecular weight gelatin aqueous solution was 220 g and the amount of the 20.5% by mass titanium oxide sol was 590.2 g, the same as the coating solution 1 for high refractive index layer, A coating solution 8 for a high refractive index layer was prepared.

<Preparation of coating solution 9 for high refractive index layer>
Except that the amount of the 5.0% by mass low molecular weight gelatin aqueous solution was 150 g and the amount of the 20.5% by mass titanium oxide sol was 731.7 g, the same as the coating solution 1 for high refractive index layer, A coating solution 9 for a high refractive index layer was prepared.

<Preparation of coating solution 10 for high refractive index layer>
Except for the amount of the 5.0% by weight low molecular weight gelatin aqueous solution being 150 g and the amount of the 20.5% by weight titanium oxide sol being 768.3 g, the same as the coating solution 1 for high refractive index layer, A coating solution 10 for a high refractive index layer was prepared.

<Preparation of coating solution 11 for high refractive index layer>
As a water-soluble polymer, 237.5 g of a 5.0% by mass low molecular weight gelatin aqueous solution and 237.5 g of a 5.0% by mass polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA217) were used (low molecular weight gelatin and A coating solution 11 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the mass ratio with polyvinyl alcohol was 1: 1).

<Preparation of coating liquid 12 for high refractive index layer>
A coating solution 12 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.10 g.

<Preparation of coating liquid 13 for high refractive index layer>
A coating solution 13 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.15 g.

<Preparation of coating solution 14 for high refractive index layer>
A coating solution 14 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.20 g.

<Preparation of coating solution 15 for high refractive index layer>
A coating solution 15 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.55 g.

<Preparation of coating liquid 16 for high refractive index layer>
A coating solution 16 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.70 g.

<Preparation of coating liquid 17 for high refractive index layer>
A coating solution 17 for a high refractive index layer was prepared in the same manner as the coating solution 1 for a high refractive index layer except that the amount of calcium chloride anhydride was 0.05 g.

<Preparation of coating liquid 18 for high refractive index layer>
A high refractive index layer coating solution 18 was prepared in the same manner as the high refractive index layer coating solution 1 except that the amount of calcium chloride anhydride was 0.95 g.

<Preparation of coating solution 19 for high refractive index layer>
A coating liquid 19 for a high refractive index layer was prepared in the same manner as the coating liquid 6 for a high refractive index layer, except that calcium chloride anhydride was not used.

<Preparation of coating solution 20 for high refractive index layer>
A high refractive index layer coating solution 20 was prepared in the same manner as the high refractive index layer coating solution 7 except that calcium chloride anhydride was not used.

<Preparation of coating liquid 21 for high refractive index layer>
After mixing 40 parts by mass of titanium oxide particles (volume average particle size: 15 nm), 2 parts by mass of dioctylsulfosuccinate (surfactant), and 58 parts by mass of toluene, the mixture was dispersed for 48 hours using a ball mill, A titanium oxide sol was prepared. Next, a thermosetting acrylic resin was added to the prepared titanium oxide sol at a mass 1.5 times the mass of the titanium oxide to prepare a coating solution 21 for a high refractive index layer.

<Preparation of coating solution 1 for low refractive index layer>
184 g of an aqueous dispersion of 21.4 mass% colloidal silica (average particle size: 6 nm), 369 g of a 5.0 mass% low molecular weight gelatin (weight average molecular weight: 16000) aqueous solution, and 120 g of a 1.0 mass% gellan gum aqueous solution 120 g While stirring, the mixture was gradually stirred. Next, 0.84 g of 5.0% by mass of 2-DB-500E (manufactured by NOF Corporation) is added as a surfactant, and pure water is added to make the total mass 850 g, thereby reducing the low refractive index. Layer coating solution 1 was prepared.

<Preparation of coating solution 2 for low refractive index layer>
The low refractive index layer coating liquid 2 was prepared in the same manner as the low refractive index layer coating liquid 1 except that a 1.0 mass% alginic acid aqueous solution was used instead of the 1.0 mass% gellan gum aqueous solution. Prepared.

<Preparation of coating solution 3 for low refractive index layer>
The low refractive index layer coating solution 3 was prepared in the same manner as the low refractive index layer coating solution 1 except that a 1.0 mass% pectin aqueous solution was used instead of the 1.0 mass% gellan gum aqueous solution. Prepared.

<Preparation of coating solution 4 for low refractive index layer>
A low refractive index layer coating solution 4 was prepared in the same manner as the low refractive index layer coating solution 1 except that 655 g of a 3.0% by weight xanthan gum aqueous solution was used as the water-soluble polymer.

<Preparation of coating solution 5 for low refractive index layer>
Instead of 475 g of 5.0% by weight low molecular weight gelatin aqueous solution, 237.5 g of 5.0% by weight low molecular weight gelatin aqueous solution and 23.75 g of polyvinyl alcohol (Kuraray Co., Ltd., PVA217) were used (low molecular weight). A low refractive index layer coating solution 5 was prepared in the same manner as the low refractive index layer coating solution 1 except that the mass ratio of gelatin to polyvinyl alcohol was 1: 1).

<Preparation of coating solution 6 for low refractive index layer>
To 184 g of 21.4 mass% colloidal silica, 369 g of 5.0 mass% low molecular weight gelatin (weight average molecular weight: 16000) aqueous solution, 120 g of 1.0 mass% gellan gum, and 0.39 g of calcium chloride anhydride were stirred. While stirring, the mixture was gradually stirred. Next, 0.84 g of 5.0% by mass of 2-DB-500E (manufactured by NOF Corporation) is added as a surfactant, and pure water is added to make the total mass 850 g, thereby reducing the low refractive index. A layer coating solution 6 was prepared.

Example 1
<Preparation of infrared shielding film>
Using a slide hopper coating apparatus capable of coating 16 layers, the above-mentioned coating solution 1 for high refractive index layer and coating solution 1 for low refractive index layer are kept at 45 ° C. and heated to 45 ° C. On a polyethylene terephthalate (PET) film (Toyobo Co., Ltd., A4300, double-sided easy-adhesive layer), the film thickness upon drying is 175 nm per layer for the low refractive index layer and 130 nm per layer for the high refractive index layer. In this way, a total of 16 layers were applied simultaneously, 8 layers alternately. Immediately after application, 5 ° C. cold air is blown for 5 minutes, then 80 ° C. hot air is blown to dry, and the total of the high refractive index layer and the low refractive index layer is 16 layers, and the red has 15 intermediate layers. An outer shielding film (Sample 1, total film thickness: 52.4 μm) was produced.

(Example 2)
An infrared shielding film (Sample 2) was produced in the same manner as in Example 1 except that the low refractive index layer coating solution 2 was used instead of the low refractive index layer coating solution 1.

(Example 3)
An infrared shielding film (Sample 3) was produced in the same manner as in Example 1 except that the low refractive index layer coating solution 3 was used instead of the low refractive index layer coating solution 1.

Example 4
Example except that the coating solution 2 for the high refractive index layer 2 was used instead of the coating solution 1 for the high refractive index layer, and the coating solution 4 for the low refractive index layer was used instead of the coating solution 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 4) was produced.

(Example 5)
An infrared shielding film (Sample 5) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 3 was used instead of the high refractive index layer coating solution 1.

(Example 6)
An infrared shielding film (sample 6) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 4 was used instead of the high refractive index layer coating solution 1.

(Example 7)
An infrared shielding film (Sample 7) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 5 was used instead of the high refractive index layer coating solution 1.

(Example 8)
An infrared shielding film (Sample 8) was prepared in the same manner as in Example 1 except that the high refractive index layer coating solution 6 was used instead of the high refractive index layer coating solution 1.

Example 9
An infrared shielding film (sample 9) was prepared in the same manner as in Example 1 except that the high refractive index layer coating solution 7 was used instead of the high refractive index layer coating solution 1.

(Example 10)
An infrared shielding film (sample 10) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 8 was used instead of the high refractive index layer coating solution 1.

(Example 11)
An infrared shielding film (Sample 11) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 9 was used instead of the high refractive index layer coating solution 1.

(Example 12)
An infrared shielding film (sample 12) was produced in the same manner as in Example 1 except that the high refractive index layer coating solution 10 was used instead of the high refractive index layer coating solution 1.

(Example 13)
Example except that the coating liquid 11 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer, and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 13) was produced.

(Example 14)
Example except that the coating solution 12 for the high refractive index layer was used instead of the coating solution 1 for the high refractive index layer, and the coating solution 5 for the low refractive index layer was used instead of the coating solution 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 14) was produced.

(Example 15)
Example except that the coating liquid 13 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 15) was produced.

(Example 16)
Example except that the coating liquid 14 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 16) was produced.

(Example 17)
Example except that the coating liquid 15 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 17) was produced.

(Example 18)
Example except that the coating liquid 16 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 18) was produced.

(Comparative Example 1)
Example except that the coating solution 17 for the high refractive index layer was used instead of the coating solution 1 for the high refractive index layer, and the coating solution 5 for the low refractive index layer was used instead of the coating solution 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 19) was produced.

(Comparative Example 2)
Example except that the coating liquid 18 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer, and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 20) was produced.

(Comparative Example 3)
Example except that the coating liquid 19 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer, and the coating liquid 5 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 21) was produced.

(Comparative Example 4)
Example except that the coating solution 20 for the high refractive index layer was used instead of the coating solution 1 for the high refractive index layer, and the coating solution 5 for the low refractive index layer was used instead of the coating solution 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 22) was produced.

(Comparative Example 5)
Example except that the coating liquid 19 for the high refractive index layer was used instead of the coating liquid 1 for the high refractive index layer, and the coating liquid 6 for the low refractive index layer was used instead of the coating liquid 1 for the low refractive index layer. In the same manner as in Example 1, an infrared shielding film (Sample 23) was produced.

(Comparative Example 6)
On a polyethylene terephthalate film having a thickness of 50 μm, a thermosetting acrylic resin (refractive index layer coating solution 7) having a refractive index of 1.47 is applied so as to have a dry film thickness of 175 nm, and dried and cured to reduce the thickness. A refractive index layer was formed. Thereafter, the coating solution 21 for the high refractive index layer was applied on the low refractive index layer so as to have a dry film thickness of 350 nm, and thermally cured at 90 ° C. for 20 minutes. On the high refractive index layer, three units composed of a low refractive index layer / a high refractive index layer are laminated in the same manner, and four high refractive index layers and four low refractive index layers are provided (a total of eight layers). ) An infrared shielding film (Sample 24, total film thickness: 52.11 μm) was prepared.

(Comparative Example 7)
<Preparation of dispersion A>
109 parts by mass of rutile titanium oxide (Ishihara Sangyo Co., Ltd., TTO-55A, particle size 30 to 50 nm, surface treatment with aluminum hydroxide, refractive index 2.6), 11 parts of polyethyleneimine block polymer as a dispersant 1 part, a solution obtained by mixing 180 parts by mass of polypropylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA, manufactured by Wako Pure Chemical Industries, Ltd.) is dispersed for 24 minutes with a bead mill disperser using zirconia beads having an average diameter of 0.5 mm. After that, the zirconia beads having an average diameter of 0.1 mm were switched, and further dispersed for 147 minutes with a bead mill disperser to obtain dispersion A.

<Preparation of solution A>
50% by mass of 4,4′-bis (β-methacryloyloxyethylthio) diphenylsulfone (refractive index after curing: 1.65) as a binder resin and 2,4,6-trimethylbenzoyldiphenylphosphine as a polymerization initiator A PGMEA solution containing 0.25% by mass of fin oxide was prepared, and this was designated as Solution A.

<Preparation of solution B>
A liquid mixture having a mixing ratio of the dispersion A and the solution A of 1: 7 (mass ratio) was prepared, and this was designated as a solution B.

<Preparation of coating liquid 22 for high refractive index layer>
A liquid mixture having a mixing ratio of the solution B and PGMEA of 1: 2 (mass ratio) was prepared, and this was used as a coating liquid 22 for a high refractive index layer.

<Method for Producing Sample 25>
2 ml of the coating solution 22 for the high refractive index layer prepared above is dropped on a polyethylene terephthalate film (Toyobo Co., Ltd., A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, and spin coater (1000 rpm, 30 seconds) After coating by Mikasa Co., Ltd., 1H-D7), it was heated at 120 ° C. for 10 minutes.

Then, a high refractive index layer is formed by irradiating an ultraviolet ray with an integrated light quantity of 2.8 J / cm ² using an electrodeless mercury lamp (manufactured by Fusion UV Systems) with an output of 184 W / cm, and further forming the high refractive index. The layer was subjected to corona discharge treatment (manufactured by Shinko Electric Instrumentation Co., Ltd., corona discharge surface reformer) for surface modification.

  As a coating solution 8 for the low refractive index layer, 2 ml of an aqueous solution of 1% by mass of hydroxyethyl cellulose (hereinafter referred to as HEC, manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped and left at room temperature for 1 minute, then at 500 rpm for 30 seconds. The coating was performed under spin coating conditions. Immediately after coating, a low refractive index layer was laminated on the high refractive index layer by placing the sample on an 80 ° C. hot plate (HPD-3000, manufactured by As One Co., Ltd.) and heating for 10 minutes.

  Further, a high refractive index layer is formed on the low refractive index layer in the same manner as described above, and an infrared shielding film (sample 25, film having three layers of high refractive index layer / low refractive index layer / high refractive index layer) is formed. The total thickness was 50.5 μm).

(Comparative Example 8)
<Preparation of coating solution 23 for high refractive index layer>
A spherical rutile-type titanium oxide (TTO-51C, manufactured by Ishihara Sangyo Co., Ltd.) having a particle size of 20 nm and methanol as a solvent are dispersed and mixed so that the volume ratio is 1:10. 23 was prepared.

<Preparation of coating solution 9 for low refractive index layer>
A spherical colloidal silica sol (manufactured by Nissan Chemical Industries, Ltd., Snowtex (registered trademark) PS) having a particle size of 10 to 15 nm (average particle size of 12 nm) and methanol as a solvent so as to have a volume ratio of 1:10. By dispersing and mixing, a coating solution 9 for a low refractive index layer was prepared.

Coating solution 23 for high refractive index layer and coating solution for low refractive index layer on polyethylene terephthalate film (made by Teijin DuPont Films, Teijin (registered trademark) Tetron (registered trademark) film, highly transparent grade) having a thickness of 50 μm 9 was used to prepare a laminate having the following seven-layer structure. Base material / high refractive index layer 23 / low refractive index layer 9 / high refractive index layer 23 / low refractive index layer 9 / high refractive index layer 23 / low refractive index layer 9 / high refractive index layer 23
Furthermore, silica sol (manufactured by Nissan Chemical Industries, Ltd., methanol silica sol) having a particle size of 10 to 20 nm (average particle size: 15 nm) and methanol as a solvent are dispersed and mixed so that the volume ratio is 1:20. A top layer coating solution is prepared, and coated on the seven-layered alternating laminated film under the condition that the thickness after drying is 125 nm, dried to form the top layer, and an infrared shielding film (sample 26, film The total thickness was 51.7 μm).

(Evaluation)
<Refractive index>
Samples were prepared by coating each layer (high refractive index layer, low refractive index layer) on which the refractive index was measured on a substrate (PET film), and the refractive index was determined according to the following method. .

  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. In Sample 23, since the gelation of the low refractive index layer was severe and the refractive index could not be measured with a film surface quality that could not withstand evaluation, ND was displayed.

<The elastic modulus of the intermediate layer>
A high refractive index layer coating solution, a low refractive index layer coating solution, and each sample having a dry film thickness of 2 μm were prepared by coating two layers on a glass substrate, and the nanoindentation method (manufactured by Seiko Instruments Inc.) , A scanning probe microscope SPI3800N equipped with a device manufactured by HYSITRON, TriboScope, indenter measured at 90 ° Cube corner tip, maximum load 20 μN), elastic modulus of single layer of high refractive index layer and low refractive index layer The ratio between the higher one and the elastic modulus of the film obtained by coating and drying two layers was determined by the measurement n number n = 3.

<Thickness of intermediate layer>
About each infrared shielding film produced above, cut with a diamond cutter, EDX analysis of the cut surface, and create a particle concentration profile of the metal oxide particles of the high refractive index layer and the metal oxide particles of the low refractive index layer The thickness of the portion having a concentration of 10 to 50% with respect to the maximum particle amount was taken as the thickness of the intermediate layer. In addition, the apparatus used for EDX analysis was an apparatus which mounted EDX Apollo40 by EDAX with respect to Hitachi, Ltd. scanning electron microscope S-4800.

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

<Interlayer adhesion>
About each produced said infrared shielding film, based on the bending test method based on JISK5600-5-1 (1999), the bending tester type 1 (Imoto Seisakusho make, model: IMC-AOF2, mandrel diameter φ20mm) After performing a bending test 1000 times, the infrared shielding film was visually observed, and interlayer adhesion was evaluated according to the criteria shown in Table 1 below.

<Glass adhesiveness>
60 parts by mass of ethyl acetate and 20 parts by mass of toluene were mixed, and 20 g of an acrylic adhesive (Alontack M-300, manufactured by Toagosei Co., Ltd.) was further added to prepare an adhesive layer coating solution. This coating liquid, each infrared shielding film after the bending test in the same manner as the interlayer adhesion test described above, solid content after drying was coated with a 5 g / m ^2, at 80 ° C., 2 It dried for minutes and produced the adhesion layer. After bonding this to a glass plate with a thickness of 1.3 mm (Matsunami Glass Industry Co., Ltd., “slide glass white edge polishing”), on a roll with a diameter of 15.2 cm (6 inches) and a width of 45 mm, A steel roller covered with a rubber having a thickness of 6 mm was used, and the film and the glass were pressure-bonded with the roller so that only the weight of the roller was applied to the infrared shielding film surface. Forty-eight hours after pressure bonding, 90 ° peel adhesive strength (N / 20 mm) was measured. The measurement conditions for 90 ° peel adhesive strength were a peel angle of 90 °, a tensile speed of 300 mm / min, a temperature of 23 ° C., and a relative humidity of 50% RH.

  The structure of the infrared shielding film obtained by each Example and each comparative example is shown to Tables 2-3, and the evaluation result of each infrared shielding film is shown to Tables 4-5, respectively.

  As is clear from the results of Tables 4 to 5 above, an intermediate layer having an elastic modulus 2 to 100 times the higher elastic modulus of the elastic modulus of the high refractive index layer and the elastic modulus of the low refractive index layer is provided The infrared shielding film of the present invention can reduce the diffusion of the metal oxide particles of the high refractive index layer and the metal oxide particles of the low refractive index layer from each layer, and as a result, the refractive index. The difference becomes large, and even a small number of layers can have a high infrared reflectance. Moreover, the unevenness | corrugation in the interface of a high refractive index layer and a low refractive index layer and film surface by aggregation of a metal oxide particle can be reduced, and it becomes an infrared shielding film with high adhesiveness with glass etc. Furthermore, when Sample 9 and Sample 20 are compared, it can be seen that the interlayer adhesion is maintained even when the content of the metal oxide particles is high.

Claims (5)

On the substrate
A high refractive index layer comprising a first water-soluble polymer and first metal oxide particles;
A low refractive index layer comprising a second water-soluble polymer and second metal oxide particles;
An intermediate layer located between the high refractive index layer and the low refractive index layer;
Having at least one unit consisting of
The refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more,
The intermediate layer has an elastic modulus that is 2 to 100 times the higher one of the elastic modulus of the high refractive index layer and the elastic modulus of the low refractive index layer.   The infrared shielding film according to claim 1, wherein the intermediate layer includes a gel formed from a polyvalent metal compound and a thickening polysaccharide.   The infrared shielding film of Claim 1 in which the said intermediate | middle layer contains the gel formed from two types of thickening polysaccharides which are mutually different. A coating solution for a high refractive index layer comprising a first water-soluble polymer, first metal oxide particles, and a first compound;
A coating solution for a low refractive index layer comprising a second water-soluble polymer, second metal oxide particles, and a second compound;
Including the step of applying
The method for producing an infrared shielding film, wherein the first compound and the second compound are compounds that react with each other to form a gel.   The infrared shielding body which provided the infrared shielding film of any one of Claims 1-3, or the infrared shielding film obtained by the manufacturing method of Claim 4 on the at least one surface of the base | substrate. .