JP5729144B2 - Infrared shielding film and infrared shielding body - Google Patents

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.

  The light emitted from the sun has a wide spectrum from the ultraviolet region to the infrared light region. Visible light has a wavelength range of 380 to 780 nm ranging from purple to yellow to red light, and occupies about 45% of sunlight. As for infrared light, those close to visible light are called near-infrared rays (wavelength 780 to 2500 nm), and more than that are called mid-infrared rays and occupy about 50% of sunlight. The intensity of light energy in this region is as small as about one-tenth or less compared with ultraviolet light, but the thermal effect is large, and when absorbed by a substance, it is released as heat, resulting in an increase in temperature. For this reason, it is also called a heat ray, and by blocking these rays, the temperature rise in the room can be suppressed. Further, it is possible to suppress the heat of the winter in the cold region from being dissipated outside.

  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.

  Then, it replaces with the dry film forming method which has the above subjects, and the method of forming an infrared shielding film using a wet coating method is known.

  For example, a refractive index layer coating solution in which a thermosetting silicone resin or ultraviolet curable acrylic resin containing metal oxide or metal compound fine particles is dispersed in an organic solvent is applied onto a substrate by a wet coating method using a bar coater. A method for forming a transparent laminate by coating (for example, see Patent Document 1) and a method for alternately laminating methanol dispersion slurry of titanium oxide particles and methanol silica sol (for example, see Patent Document 2) are disclosed. Yes.

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

  However, in a film forming method using a thermosetting silicone resin or an ultraviolet curable acrylic resin or a method of forming a film using a sol, the formed film is too hard, so that the flexibility is low. The coating film is disturbed by repeated temperature and humidity changes over time until it is applied to the window glass of the vehicle, causing problems such as a decrease in infrared reflectance and a decrease in visible light transmittance, and application to windows due to a decrease in flexibility. It has been found that there is a problem that the surface of the coating film is cracked by handling such as during transportation and the desired performance cannot be obtained sufficiently.

  The present invention has been made in view of the above problems, and its purpose is to be inexpensive and capable of increasing the area, to maintain flexibility even after temperature and humidity changes, and to have high visible light transmittance and high infrared reflectance. An object is to provide an infrared shielding film and an infrared shielding body having an infrared shielding film provided on at least one surface.

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

1. On the substrate
It has at least one unit composed of a high refractive index layer and a low refractive index layer containing a binder resin and metal oxide particles, and the refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more And at least one of the high refractive index layer or the low refractive index layer is, as the binder resin , (1) unmodified polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less, or cationic modification, anion modification or nonion modification. Copolymer obtained by copolymerizing the modified polyvinyl alcohol with (2) one or more polymerizable vinyl monomers selected from the group consisting of unsaturated carboxylic acids and salts and esters thereof An infrared shielding film comprising :
2. The copolymer is (1) one or more polymerizable vinyls selected from the group consisting of polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less, and (2) unsaturated carboxylic acid and salts and esters thereof. 1. A copolymer obtained by copolymerizing a monomer with a mass ratio of 0.5: 9.5 to 9.5: 0.5. An infrared shielding film according to claim 1;
3. The polymerizable vinyl polymer is acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid and salts thereof, and the following general formula (I):

In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 4 carbon atoms,
2. One or more selected from the group consisting of unsaturated carboxylic acid esters represented by the above 2. An infrared shielding film according to claim 1;
4). 2. The polymerizable vinyl monomer is acrylic acid or a salt thereof and / or methyl methacrylate. An infrared shielding film according to claim 1;
5. The polymerizable vinyl monomer is a mixture of acrylic acid or a salt thereof and methyl methacrylate, and a weight ratio of acrylic acid or a salt thereof to methyl methacrylate is from 3: 7 to 0.5: 9.5 (acrylic acid). Or a salt thereof: methyl methacrylate). An infrared shielding film according to claim 1;
6). The content ratio of the modified polyvinyl alcohol is 5 to 45% by mass with respect to the binder resin. To 5. An infrared shielding film according to any one of
7). 1. At least one of the high refractive index layer or the low refractive index layer contains boric acid and a salt thereof and / or borax. To 6. An infrared shielding film according to any one of
8). 1. The high refractive index layer comprises rutile type titania. To 7. An infrared shielding film according to any one of
9. Above 1. To 8. The infrared shielding body which provided the infrared shielding film as described in any one of these on the at least one surface of the base | substrate.

  According to the present invention, an infrared shielding film that can be manufactured at low cost, can have a large area, has high infrared reflectance and visible light transmittance, and can maintain flexibility even after temperature and humidity changes, and the same are used. An infrared shield is provided.

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

  According to one aspect of the present invention, an infrared shielding film having at least one unit comprising a high refractive index layer and a low refractive index layer containing a binder resin and metal oxide particles is provided on a substrate. At this time, the refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more. And at least 1 layer of the said high refractive index layer or the said low refractive index layer has the characteristics in the point containing modified polyvinyl alcohol as said binder resin.

  With such a configuration, the mechanism by which the above-described operational effects can be obtained is not yet clear, but the mechanism of the operational effects by the configuration of the present invention is presumed as follows.

  That is, the infrared shielding film targeted by the present invention usually uses a coating solution for each of the high refractive index layer and the low refractive index layer, and the units composed of each coating solution have a sequential multilayer structure. It is manufactured with high productivity. And when using an aqueous coating solution unit, ensure the refractive index designed for each layer by preventing the coating solution components of the high refractive index layer and low refractive index layer from mixing together as much as possible. There is a need to. For that purpose, it is important to suppress interlayer mixing due to diffusion of metal oxide particles between the coating liquid units. On the other hand, in order to control the refractive index, it is necessary to increase the content of metal oxide particles in each of the high refractive index layer and the low refractive index layer. However, a coating film with a high metal oxide content is inferior in flexibility, and when the temperature and humidity change, the coating film cracks, and the infrared shielding performance, which is the original function, is greatly reduced.

  On the other hand, the infrared shielding film according to the present invention is characterized in that at least one of the high refractive index layer and the low refractive index layer contains a modified polyvinyl alcohol as a binder resin. Due to such a configuration, the metal oxide particles contained in the refractive index layer interact with the modified polyvinyl alcohol, and intermixing between the high refractive index layer and the low refractive index layer is suppressed, which is preferable red. Outer shielding properties are achieved. And as a result of providing flexibility to the refractive index layer by the interaction, an infrared shielding film excellent in durability with little occurrence of cracking or the like can be provided even when the temperature and humidity conditions are changed. it is conceivable that.

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

[Infrared shielding film]
The infrared shielding film of this embodiment includes a base material and at least one of units composed of a high refractive index layer and a low refractive index layer.

  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 that the infrared reflectance can be increased with a small number of layers. In this embodiment, in at least one of the units composed of the high refractive index layer and the low refractive index layer, the refractive index difference between the adjacent high refractive index layer and the low refractive index layer is preferably 0.1 or more. More preferably, it is 0.3 or more, More preferably, it is 0.35 or more, Especially preferably, it is 0.4 or more. When the infrared shielding film has a plurality of units of a high refractive index layer and a low refractive index layer, the refractive index difference between the high refractive index layer and the low refractive index layer in all the units is within the preferred range. Is preferred. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used. Moreover, in the infrared shielding film of this form, the preferable refractive index of a high refractive index layer is 1.80-2.50, More preferably, it is 1.90-2.20. Moreover, the preferable refractive index of a low refractive index layer is 1.10-1.60, More preferably, it is 1.30-1.50.

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

  Furthermore, as an optical characteristic of the infrared shielding film of this embodiment, the transmittance in the visible light region shown in JIS R3106-1998 is 50% or more, preferably 75% or more, more preferably 85% or more. In addition, it is preferable that the region having a wavelength of 900 nm to 1400 nm has a region where the reflectance exceeds 50%.

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

  The infrared shielding film of this form should just have the structure which contains at least 1 unit comprised from a high refractive index layer and a low refractive index layer on a base material. As the number of layers of the high refractive index layer and the low refractive index layer, from the above viewpoint, the range of the total number of layers is 100 layers or less, that is, 50 units or less, more preferably 40 layers (20 units) or less. More preferably, it is 20 layers (10 units) or less.

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

〔Base material〕
As a base material used for the infrared shielding film which concerns on this form, if it is formed with the transparent organic material, it will not specifically limit.

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

  As for the thickness of a base material, about 5-200 micrometers is preferable, More preferably, it is 15-150 micrometers.

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

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

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

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

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

[Metal oxide particles]
Examples of the metal oxide particles that can be used in the infrared shielding film according to the present embodiment include titanium dioxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, and lead oxide. , Yellow lead, zinc yellow, chromium oxide, ferric oxide, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, tin oxide, etc. Can be mentioned.

  In order to form a transparent high refractive index layer having a higher refractive index, the high refractive index layer may contain high refractive index metal oxide fine particles such as titanium and zirconia, that is, fine titanium oxide particles and fine zirconia oxide particles. preferable. In particular, it is preferable to contain rutile (tetragonal) titanium oxide particles having a volume average particle diameter of 100 nm or less.

  The volume average particle diameter of the titanium oxide particles or zirconia oxide particles used in the present invention is preferably 100 nm or less, more preferably 4 to 50 nm, and even more preferably 4 to 40 nm. A volume average particle diameter of 100 nm or less is preferable from the viewpoint of low haze and excellent visible light transmittance.

  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.

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

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

  The titanium oxide particles used in the present invention can be dispersed in an organic solvent by hydrophobizing the surface of an aqueous titanium oxide sol having a pH of 1.0 to 3.0 and a positive zeta potential of the titanium particles. It is preferable to use what was made.

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

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

  In the production method according to the above step (2), titanium dioxide hydrate is treated with at least one basic compound selected from the group consisting of alkali metal hydroxides or alkaline earth metal hydroxides. After the step (1), the titanium dioxide dispersion obtained comprises a step (2) of treating with a carboxylic acid group-containing compound and an inorganic acid. In the present invention, an aqueous sol of titanium oxide having a pH adjusted to 1.0 to 3.0 with the inorganic acid obtained in the step (2) can be used.

  The content of metal oxide particles (preferably titanium oxide particles) in the high refractive index layer is preferably 15 to 70% by mass with respect to 100% by mass of the solid content of the high refractive index layer, and is preferably 20 to 65%. It is more preferable that it is mass%, and it is further more preferable that it is 30-60 mass%.

  On the other hand, the metal oxide particles contained in the low refractive index layer are preferably silicon dioxide, and examples thereof include synthetic amorphous silica and colloidal silica. Of these, acidic colloidal silica sol is more preferably used, and colloidal silica sol dispersed in an organic solvent is more preferably used. In order to further reduce the refractive index, it is particularly preferable to use hollow fine particles having pores inside the particles as metal oxide fine particles, and hollow fine particles of silicon dioxide (silica) are most preferred.

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

  The average particle size of the metal oxide fine particles used in the low refractive index layer is determined by observing the particles themselves or the particles appearing on the cross section or surface of the refractive index layer with an electron microscope, and determining the particle size of 1,000 arbitrary particles. Measured and obtained as a simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

  The colloidal silica used in the present invention is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A-57-14091, JP-A-60-219083, JP-A-60-219084, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 No. 5, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142. , JP-A-7-179029, JP-A-7-137431, and WO94 / 26530 pamphlet. Those which are.

  Such colloidal silica may be a synthetic product or a commercially available product.

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

  The hollow fine particles used in the present invention preferably have an average particle pore size of 3 to 70 nm, more preferably 5 to 50 nm, and even more preferably 5 to 45 nm. The average particle pore size of the hollow fine particles is an average value of the inner diameters of the hollow fine particles. In the present invention, when the average particle pore diameter of the hollow fine particles is within the above range, the refractive index of the low refractive index layer is sufficiently lowered. The average particle diameter is 50 or more at random, which can be observed as an ellipse in a circular, elliptical or substantially circular shape by electron microscope observation, and obtains the pore diameter of each particle. Is obtained. In the present specification, as the average particle pore diameter, the minimum distance among the distances between the outer edges of the pore diameter that can be observed as a circle, an ellipse, a substantially circle or an ellipse, between two parallel lines Means.

  The hollow fine particles used in the present invention preferably have an outer shell thickness of 10 nm or less, more preferably 1 to 7 nm, and even more preferably 1 to 5 nm. In addition, in this specification, the outer side part of the void | hole in a hollow microparticle is called outline. A thickness of the outer shell of 10 nm or less is preferable because the haze is small and the light transmittance of the infrared shielding film is excellent. If the thickness of the outer shell is 1 nm or more, the mechanical strength of the particles is increased and the shape can be maintained in the low refractive index layer, so that formation of pores is facilitated. The average thickness of the outer shell is observed by electron microscope observation, and the average thickness of the outer shell of the pores that can be observed as a circle, ellipse, or substantially circular as an ellipse is randomly observed, and 50 or more of the outer shell of each particle is observed. The average thickness is obtained, and the number average value is obtained.

  Such hollow fine particles may be a synthetic product or a commercially available product. Here, as hollow fine particles of silicon dioxide (silica), for example, an organic silicon compound (for example, alkoxysilane such as tetraethoxysilane) is added to a calcium carbonate aqueous dispersion under alkaline conditions (for example, addition of ammonia). , Stir. Thereafter, the mixture is heated to 50 to 80 ° C. and stirred to obtain a silica-coated calcium carbonate dispersion. The silica-coated calcium carbonate dispersion is decomposed under acidic conditions (for example, acetic acid is added) to decompose calcium carbonate and generate carbon dioxide to elute calcium carbonate. After adding distilled water to the obtained dispersion, ultrafiltration is performed on the dispersion until the same amount of distilled water as that added is discharged. By performing the ultrafiltration 1 to 5 times, a dispersion containing silica hollow fine particles can be obtained.

  The content of the metal oxide particles in the low refractive index layer is preferably 0.1 to 50% by mass and 0.5 to 45% by mass with respect to 100% by mass of the solid content of the low refractive index layer. It is more preferable, it is more preferable that it is 1-40 mass%, and it is especially preferable that it is 5-30 mass%.

[Binder resin]
In the infrared shielding film according to this embodiment, the high refractive index layer and the low refractive index layer each contain a binder resin. And at least 1 layer of a high refractive index layer and a low-refractive-index layer contains modified polyvinyl alcohol as binder resin. In the following, first, the modified polyvinyl alcohol used as a binder resin in at least one of the high refractive index layer or the low refractive index layer in the infrared shielding film according to this embodiment will be described.

(Modified polyvinyl alcohol)
In this invention, there is no restriction | limiting in particular about the specific form of modified polyvinyl alcohol used as binder resin, The conventionally well-known material which performed various modification | denaturation processes can be used suitably.

  The polyvinyl alcohol used as the raw material for the modified polyvinyl alcohol used in the present invention has an average degree of polymerization of about 200 to 2400, preferably an average degree of polymerization of about 900 to 2400, and more preferably an average degree of polymerization of about 1300 to 1700. Moreover, the saponification degree of polyvinyl alcohol is preferably about 60 to 100 mol%, more preferably 78 to 96 mol%. Such a saponified polyvinyl alcohol can be produced by radical polymerization of vinyl acetate and appropriately saponifying the obtained vinyl acetate. In order to produce the desired polyvinyl alcohol, the degree of polymerization is appropriately selected. This is achieved by controlling the degree of saponification in a manner known per se.

  In addition, as such a partially saponified polyvinyl alcohol, it is also possible to use a commercially available product. Examples of preferable commercially available polyvinyl alcohol include Gohsenol EG05, EG25 (manufactured by Nippon Synthetic Chemical), PVA203 (manufactured by Kuraray Co., Ltd.), PVA204 (manufactured by Kuraray Co., Ltd.), PVA205 (manufactured by Kuraray Co., Ltd.), JP-04 (manufactured by Nihon Vinegar / Poval), JP-05 (manufactured by Nihon Vinegar / Povar), and the like are included. In addition, not only a single type of polyvinyl alcohol is used alone as a raw material for the modified polyvinyl alcohol, but also two or more types of polyvinyl alcohols having different degrees of polymerization and saponification can be used in combination as appropriate. For example, polyvinyl alcohol having an average polymerization degree of 300 and polyvinyl alcohol having an average polymerization degree of 1500 can be mixed and used.

  As the modified polyvinyl alcohol used in the present invention, one obtained by subjecting polyvinyl alcohol as a raw material described above to one or more arbitrary modification treatments can be used. Examples thereof include amine-modified polyvinyl alcohol, ethylene-modified polyvinyl alcohol, carboxylic acid-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, and thiol-modified polyvinyl alcohol. As these modified polyvinyl alcohols, commercially available products may be used, or those produced by methods known in the art can be used.

  In addition, as the modified polyvinyl alcohol of the present invention, modified polyvinyl alcohol such as polyvinyl alcohol having a terminal cation modified, an anion modified polyvinyl alcohol having an anionic group, and nonionic modified polyvinyl alcohol can also be used.

  Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups, as described in JP-A No. 61-10383, in the main chain or side chain of the polyvinyl alcohol. It is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

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

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

  Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. The block copolymer of the vinyl compound and vinyl alcohol which have the described hydrophobic group is mentioned.

  Among them, the modified polyvinyl alcohol used in the present invention is selected from the group consisting of (1) polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less, and (2) unsaturated carboxylic acid, its salt and ester, or It is preferably a copolymer (graft copolymer) obtained by copolymerizing two or more kinds of polymerizable vinyl monomers.

  In the case where the modified polyvinyl alcohol is the above graft copolymer, the above-mentioned various modified polyvinyl alcohols may be used as (1) polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less constituting the graft copolymer. Good.

  Examples of the polymerizable vinyl monomer that is polymerized with the raw material (modified) polyvinyl alcohol include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, and itaconic acid, or salts thereof (for example, alkali metals). Salts, ammonium salts, alkylamine salts), esters thereof (eg, substituted or unsubstituted alkyl esters, cyclic alkyl esters, polyalkylene glycol esters), unsaturated nitriles, unsaturated amides, aromatic vinyls, fats Group vinyls and unsaturated bond-containing heterocycles. Specifically, (a) acrylic acid esters include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, polyethylene glycol acrylate (polyethylene glycol and acrylic acid Ester) and polypropylene glycol acrylate (ester of polypropylene glycol and acrylic acid). (B) Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, and 2-ethylhexyl. Methacrylate, hydroxyethyl methacrylate, polyethylene glycol Tacrate (ester of polyethylene glycol and methacrylic acid), etc. (c) Unsaturated nitriles such as acrylonitrile, methacrylonitrile, etc. (d) Unsaturated amides such as acrylamide, dimethylacrylamide, methacrylamide, etc. (E) aromatic vinyls such as styrene and α-methylstyrene, (f) aliphatic vinyls such as vinyl acetate, and (g) unsaturated bond-containing heterocycles such as N- Examples include vinylpyrrolidone and acryloylmorpholine.

  Among them, the polymerizable vinyl polymer includes acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid and salts thereof, and the following general formula (I):

In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 4 carbon atoms,
It is preferable that it is 1 type, or 2 or more types selected from the group which consists of unsaturated carboxylic acid ester represented by these. These polymerizable vinyl monomers can be copolymerized with polyvinyl alcohol in combination of one or more, but a preferred combination is a combination of acrylic acid and a methacrylic acid ester (for example, methyl methacrylate). The mixture may be copolymerized with polyvinyl alcohol. Here, although there is no restriction | limiting in particular about the content rate of said (1) and said (2) at the time of copolymerizing polyvinyl alcohol and a polymerizable vinyl monomer, The viewpoint of fully exhibiting the effect of this invention. Is preferably 0.5: 9.5 to 9.5: 0.5, more preferably 0.5: 9.5 to 3: 7 in terms of (1) :( 2) (mass ratio). 25: 8.75 is more preferred. In addition, when a mixture of acrylic acid and methyl methacrylate is used as the polymerizable vinyl monomer, there is no particular limitation on the content ratio of acrylic acid and methyl methacrylate in the mixture, but the effect of the present invention is sufficiently achieved. From the viewpoint of exerting, acrylic acid: methyl methacrylate (mass ratio), preferably 3: 7 to 0.5: 9.5, more preferably about 1.25: 8.75. Moreover, a preferable graft copolymer consists of polyvinyl alcohol (average polymerization degree about 200-2400), methyl methacrylate, and acrylic acid, and the content rate of each structural component in the said graft copolymer is polyvinyl alcohol: acrylic acid: methacryl Methyl acid (mass ratio), preferably about 60-90: 7-38: 0.5-12, more preferably about 80: 17.5: 2.5. This mass ratio can be measured by NMR.

The modified polyvinyl alcohol of the present invention can be produced by modifying polyvinyl alcohol or a derivative thereof by a method known per se.
In particular, as a method for producing the graft copolymer as a modified polyvinyl alcohol, radical polymerization, for example, methods known per se such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization can be mentioned, Can be carried out under the usual polymerization conditions. This polymerization reaction is usually performed in the presence of a polymerization initiator, if necessary, as a reducing agent (for example, sodium erythorbate, sodium metabisulfite, ascorbic acid), a chain transfer agent (for example, 2-mercaptoethanol, α-methylstyrene). In the presence of a dimer, 2-ethylhexylthioglycolate, lauryl mercaptan) or a dispersant (for example, a surfactant such as sorbitan ester or lauryl alcohol), water, an organic solvent (for example, methanol, ethanol, cellosolve, carbitol) or the like In a mixture of Moreover, the removal method of an unreacted monomer, drying, a grinding | pulverization method, etc. may be a well-known method, and there is no restriction in particular.

  As a polymerization initiator, what is used in the said field | area can be used. For example, inorganic peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide, organic peroxides such as peracetic acid, tertiary-butyl hydroperoxide and di-n-propyl peroxydicarbonate, or 2,2 ′ -Azo compounds such as azobis (2-amidinopropane) hydrochloride and 2,2'-azobis (2,4-dimethylvaleronitrile).

  The usage-amount of a polymerization initiator is about 0.1-5.0 mass parts normally with respect to 100 mass parts of polymerizable vinyl monomers, and it is more preferable that it is 0.5-3.0 mass parts.

  In the present invention, the refractive index layer (high refractive index layer or low refractive index layer) containing the modified polyvinyl alcohol described above as the binder resin may include a curing agent. As such a curing agent, boric acid and its salts, borax, epoxy curing agents and the like are preferable.

(Other binder resins)
The binder resin other than the modified polyvinyl alcohol that can be used in the present invention is not limited as long as the high refractive index layer and the low refractive index layer containing metal oxide particles can form a coating film. It can be used. However, in view of environmental problems and flexibility of the coating film, water-soluble polymers (particularly gelatin, thickening polysaccharides, polymers having reactive functional groups) are preferable. These water-soluble polymers may be used alone or in combination of two or more.

  In the infrared shielding film of the present invention, the high refractive index layer and the low refractive index layer preferably contain a water-soluble polymer such as celluloses, thickening polysaccharides, and polymers having reactive functional groups. The water-soluble polymer referred to in the present invention is a temperature at which the water-soluble polymer is most dissolved, and is a G2 glass filter (maximum pores 40 to 50 μm) when dissolved in water at a concentration of 0.5% by mass. The mass of the insoluble matter that is filtered off when filtered is within 50 mass% of the added water-soluble polymer.

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

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

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

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

  In the present invention, it is further preferable to use two or more types of thickening polysaccharides in combination.

<Polymers having reactive functional groups>
Examples of water-soluble polymers applicable to the present invention include polymers having reactive functional groups, such as polyvinyl alcohols (unmodified), polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylic. Acrylic resins such as nitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, or acrylic acid-acrylic ester copolymer, styrene-acrylic acid copolymer, styrene -Methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, etc. Styrene acrylate resin, styrene-styrene sulfonic acid Sodium copolymer, styrene-2-hydroxyethyl acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl Vinyl acetate copolymers such as naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, etc. Polymers and their salts are mentioned. Among these, particularly preferred examples include polyvinyl alcohol (unmodified), polyvinyl pyrrolidones, and copolymers containing the same.

  The weight average molecular weight of the water-soluble polymer is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 40,000 or less are more preferable.

  The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The degree of saponification is preferably 70 to 100%, particularly preferably 80 to 99.5%. In addition, as polyvinyl alcohol, 2 or more types, such as a polymerization degree and a different kind of modification | denaturation, can also be used together. Moreover, in this invention, when using the polymer which has a reactive functional group as binder resin, you may use a hardening | curing agent. When the polymer having a reactive functional group is polyvinyl alcohol, boric acid and salts thereof, borax, an epoxy curing agent, and the like are preferable.

(Solvent binder resin)
As the solvent-based binder resin used in the present invention, photocurable, electron beam curable, and thermosetting acrylic, epoxy, silicone, urethane, fluororesin, and the like are preferable.

  In the present invention, the binder resin is contained in each of the high refractive index layer and the low refractive index layer, but the content of the binder resin in each refractive index layer is 100% by mass with respect to the total mass of the refractive index layer. The range is preferably 5.0% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less. When the amount of the binder resin is small, there is a greater tendency for the film surface to be disturbed and the transparency to deteriorate during drying after coating the refractive index layer. On the other hand, if the content is 50% by mass or less, the relative content of the metal oxide becomes appropriate, and it becomes easy to increase the difference in refractive index between the high refractive index layer and the low refractive index layer.

  The content ratio of the modified polyvinyl alcohol in the high refractive index layer and / or the low refractive index layer containing the modified polyvinyl alcohol described above as the binder resin is preferably 5 to 100% by mass with respect to the total mass of the binder resin. It is 45 mass%, More preferably, it is 10-40 mass%, More preferably, it is 25-35 mass%. If this content rate is 5 mass% or more, there exists an advantage that high coating-film intensity | strength is obtained. On the other hand, when the content is 45% by mass or less, there is an advantage that high visible light transmittance can be obtained.

[Other additives]
Various additives can be used in the high refractive index layer and the low refractive index layer as necessary. One example is described below.

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

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

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

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

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

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

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

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

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

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

(Other additives)
In addition, the high refractive index layer or the low refractive index layer is, for example, an ultraviolet absorber described in JP-A-57-74193, JP-A-57-87988, or JP-A-62-261476, -74192, 57-87989, 60-72785, 61-14659, JP-A-1-95091 and 3-13376, etc., Various surfactants of anions, cations or nonions, such as JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771 and JP-A-4-219266 The optical brighteners described, pH adjusters such as sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, Foams, lubricants such as diethylene glycol, preservatives, antistatic agents, may contain various known additives such as a matting agent.

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

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

  In the method for producing an infrared shielding film of the present invention, a unit composed of a high refractive index layer and a low refractive index layer is laminated on a base material. It is preferable to form a laminate by alternately applying and drying the refractive index layer. Specific examples include the following: (1) A high refractive index layer coating solution is applied onto a substrate and dried to form a high refractive index layer, and then a low refractive index layer coating solution is applied and dried. A method of forming an infrared shielding film by forming a low refractive index layer; (2) applying a low refractive index layer coating solution on a substrate and drying to form a low refractive index layer; A method of applying an index layer coating solution and drying to form a high refractive index layer and forming an infrared shielding film; (3) On a substrate, a high refractive index layer coating solution and a low refractive index layer coating solution; A method of forming an infrared shielding film including a high refractive index layer and a low refractive index layer; (4) a high refractive index layer coating solution and a low And a method of forming an infrared shielding film including a high refractive index layer and a low refractive index layer by simultaneously coating with a refractive index layer coating solution and drying.Among these, the method (4), which is a simpler manufacturing process, is preferable.

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

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

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

  It is preferable that the density | concentration of the resin binder in a high refractive index layer coating liquid is 1-10 mass%. Moreover, it is preferable that the density | concentration of the metal oxide particle in a high refractive index layer coating liquid is 1-50 mass%.

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

  In the present invention, the modified polyvinyl alcohol is contained in the coating liquid for forming at least one of the high refractive index layer or the low refractive index layer, and the preferable addition amount thereof is the finally formed high refractive index layer. Alternatively, the content in the low refractive index layer may be taken into consideration, and the content may be adjusted as appropriate within the above-described resin binder concentration.

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

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

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

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

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

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

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

  That is, according to the further another form of this invention, the infrared shielding body which provided the infrared shielding film which concerns on this invention in the at least one surface of the base | substrate is also provided.

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

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

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

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

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

  Insulation performance and solar heat shielding performance of infrared shielding films or infrared shields are generally obtained from JIS R 3209 (multi-layer glass) and JIS R 3106 (transmittance, reflectance, emissivity, and solar heat of plate glass). Rate test method) and JIS R 3107 (calculation method of thermal resistance of plate glass and heat transmissivity in architecture).

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

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

Example 1
<Production of infrared shielding film>
[Preparation of Infrared Shielding Film Sample 101]
(Preparation of coating liquid L1 for low refractive index layer)
9.18 parts of a 23.5% by weight aqueous solution of polyaluminum chloride (manufactured by Taki Chemical; Takibine # 1500), 340 parts of a 15% by weight aqueous solution of colloidal silica (manufactured by Nissan Chemical Co., Ltd .; Snowtex OUP), and boric acid After mixing 103.4 parts of a 5.5% by weight aqueous solution and 4.75 parts of a 2.1% by weight aqueous lithium hydroxide solution, the mixture was dispersed using a high-pressure homogenizer disperser. After the dispersion, the silicon oxide dispersion L1 was prepared by finishing 1000 parts with pure water.

  Next, the dispersion 1 was heated to 45 ° C., 100 parts of pure water and 400 parts of a 4.0% by weight aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.) were added with stirring, and then a cationic surfactant was used. As a matter of fact, 0.50 parts of a 5 mass% aqueous solution of a quaternary ammonium salt cationic surfactant (Nissan Cation-2-DB-500E manufactured by NOF) was added to prepare a coating solution L1 for a low refractive index layer. .

(Preparation of coating liquid H1 for high refractive index layer)
28.9 parts by mass of a 20.0% by mass titanium oxide sol aqueous dispersion containing rutile type titanium oxide fine particles having a volume average particle size of 35 nm, 5.41 parts by weight of a 14.8% by mass aqueous solution of picolinic acid, and 2.1 parts of lithium hydroxide. After mixing 3.92 parts of a 1% by mass aqueous solution, the mixture was dispersed using a high-pressure homogenizer disperser to prepare a titanium oxide dispersion H1.

  Next, in 10.3 parts of pure water, 130 parts of a 1.0% by weight aqueous solution of thickening polysaccharide tamarind seed gum, 10.3 parts of a 5.0% by weight aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.), 17.3 parts of a 14.8% by weight aqueous solution of picolinic acid and 2.58 parts of a 5.5% by weight aqueous solution of boric acid were sequentially added while mixing, and then 38.2 parts of titanium oxide dispersion H1 was mixed. While adding. Furthermore, 0.050 part of a 5% by mass aqueous solution of a quaternary ammonium salt-based cationic surfactant (Nissan Cation-2-DB-500E manufactured by NOF) was added, and finally it was finished to 223 parts with pure water, resulting in high refraction. A rate layer coating solution H1 was prepared.

(Preparation of sample 101)
Using a slide hopper coating apparatus capable of coating 9 layers, the low refractive index layer coating solution 1 and the high refractive index layer coating solution 1 were heated to 45 ° C. while being heated to 45 ° C. On the polyethylene terephthalate film (Toyobo A4300: double-sided easy-adhesive layer), a total of 9 layers were formed so that the thickness of the dried layer was 150 nm for each low refractive index layer and 150 nm for each high refractive index layer. Simultaneous multi-layer coating of layers was performed.

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

  After completion of the setting, warm air of 80 ° C. was blown and dried to prepare a multi-layer coated product consisting of 9 layers.

On the above 9-layer multilayer coated product, the 9-layer multilayer coating was further performed twice to prepare a sample 101 having a total of 27 layers.
[Preparation of Infrared Shielding Film Sample 102]
(Preparation of coating liquid L2 for low refractive index layer)
In the preparation of the low refractive index layer coating liquid L1 used for the preparation of the sample 101, 400 parts of a 4.0% by weight aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.) and 4 parts of a polyvinyl alcohol aqueous solution (PVA235, manufactured by Kuraray Co., Ltd.) A coating solution L2 for a low refractive index layer was prepared in the same manner except that it was replaced with 400 parts of a 0.0 mass% aqueous solution.

(Preparation of sample 102)
A sample 102 was prepared in the same manner as in the preparation of the sample 101 except that the low refractive index layer coating liquid L2 was used instead of the low refractive index layer coating liquid L1.
[Preparation of Infrared Shielding Film Sample 103]
(Preparation of modified polyvinyl alcohol HPVA1)
A separable flask equipped with a cooling reflux tube, a dropping funnel, a thermometer, a nitrogen introduction tube and a stirring device was charged with 175.8 g of PVA (polymerization degree 1700, saponification degree 88%) and 582.3 g of ion-exchanged water and dispersed at room temperature. And then completely dissolved at 95 ° C. Next, 5.4 g of acrylic acid and 37.3 g of methyl methacrylate were added, and after raising the temperature to 50 ° C. after substitution with nitrogen, 8.5 g of tertiary butyl hydroperoxide and 8.5 g of sodium erythorbate were added. The reaction was terminated to obtain a modified polyvinyl alcohol HPVA1. The obtained modified polyvinyl alcohol HPVA1 was dried and pulverized to obtain a 4.0% by mass aqueous solution.

(Preparation of coating liquid L3 for low refractive index layer)
In the preparation of the low refractive index layer coating liquid L2 used for the preparation of the sample 101, a polyvinyl alcohol aqueous solution (PVA217, manufactured by Kuraray Co., Ltd.) was used instead of 400 parts of a 4.0% by weight aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.). The coating solution L3 for the low refractive index layer was prepared in the same manner except that 280 parts of 4.0% by weight aqueous solution of) and 120 parts of 4.0% by weight aqueous solution of modified polyvinyl alcohol HPVA1 were used.

(Method for manufacturing sample 103)
A sample 103 was prepared in the same manner as in the preparation of the sample 101 except that the low refractive index layer coating liquid L3 was used instead of the low refractive index layer coating liquid L1.
[Preparation of Infrared Shielding Film Sample 104]
In the preparation of the coating liquid L3 for the low refractive index layer of Sample 103, 4.0 mass of polyvinyl alcohol (PVA235, manufactured by Kuraray Co., Ltd.) instead of 280 parts of a 4.0 mass% aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.). An infrared shielding film sample 104 was produced in the same manner except that 280 parts of a% aqueous solution was used.
[Preparation of Infrared Shielding Film Samples 105 to 106]
As shown in Table 1, infrared shielding film samples 105 to 106 were prepared in the same manner except that the layer to which the coating solution for the low refractive index layer using the modified polyvinyl alcohol aqueous solution was applied was changed. did.
[Preparation of Infrared Shielding Film Samples 107 to 108]
As shown in Table 1, in the preparation of the low refractive index layer coating liquid L3 used for the preparation of the sample 103, 280 parts of a 4.0% by weight aqueous polyvinyl alcohol solution (PVA217, manufactured by Kuraray Co., Ltd.), and modified polyvinyl Instead of 120 parts of 4.0% by weight aqueous solution of alcohol HPVA1, 200 parts of 4.0% by weight aqueous solution of polyvinyl alcohol aqueous solution (PVA217, manufactured by Kuraray Co., Ltd.) and 200 parts of 4.0% by weight aqueous solution of modified polyvinyl alcohol HPVA1 Infrared shielding film samples 107 to 108 were produced in the same manner except that (Sample 107) was replaced with (Sample 108), or 400 parts of a 4.0% by weight aqueous solution of modified polyvinyl alcohol HPVA1 was replaced (Sample 108).
[Preparation of Infrared Shielding Film Samples 109 to 112]
As shown in Table 1, in the synthesis of modified polyvinyl alcohol HPVA1, modified polyvinyl alcohols HPVA2 to HPVA6 were synthesized by changing the polymerization degree of polyvinyl alcohol as a synthesis raw material.

Next, in the preparation of the sample 103, infrared shielding film samples 109 to 112 were prepared in the same manner except that HPVA2 to HPVA6 were used instead of the modified polyvinyl alcohol HPVA1.
[Preparation of Infrared Shielding Film Samples 113 to 114]
As shown in Table 1, in preparation of the sample 103, instead of the 4.0 mass% aqueous solution of the modified polyvinyl alcohol HPVA1 used for the preparation of the coating solution L3 for the low refractive index layer, cationized modified PVA (manufactured by Nippon Synthetic Chemical; Infrared shielding film samples 113 to 114 were prepared in the same manner except that 4.0% by mass aqueous solutions of K-210) and hydrophilic group-modified PVA (manufactured by Nippon Synthetic Chemical; Ecomati WO-320R) were used.

<Evaluation of infrared shielding film>
The following performance evaluation was performed about each infrared shielding film produced above.

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

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

As a result of measuring the refractive index of each layer according to the above method, it was confirmed that the refractive index difference between the high refractive index layer and the low refractive index layer was 0.1 or more.
(Measurement of visible light transmittance and near infrared transmittance)
Using the spectrophotometer (using an integrating sphere, manufactured by Hitachi, Ltd., U-4000 type), the transmittance in the region of 300 nm to 2000 nm of the infrared shielding film samples 101 to 114 was measured. The visible light transmittance was a transmittance value at 550 nm, and the infrared transmittance was a transmittance value at 1200 nm.

(Temperature and humidity change durability evaluation)
The infrared shielding film samples 101 to 114 were placed in a high-temperature and high-humidity environment at 40 ° C. and 80% for 4 hours, then changed to an environment at 20 ° C. and 50% over 2 hours, and left in that state for 4 hours. One cycle is to return to the state of 80% at 40 ° C. over time, and after performing the temperature and humidity change durability test for a total of 6 cycles, the visible light transmittance and infrared transmittance are obtained again in the same manner as described above. It was.

  Further, each infrared shielding film sample subjected to the temperature and humidity change durability test was subjected to a bending tester type 1 (made by Imoto Seisakusho, model IMC-AOF2, based on a bending test method based on JIS K5600-5-1. Using a mandrel diameter (φ20 mm), after 30 bending tests, the surface of the infrared shielding film was visually observed, and the coating strength was evaluated according to the following criteria.

5: No folding traces or cracks are observed on the infrared shielding film surface 4: Slight folding traces are observed on the infrared shielding film surface 3: Slight irregularities are observed on the infrared shielding film surface 2: Slight microcracks are observed on the surface of the infrared shielding film 1: Many obvious cracks are generated on the surface of the infrared shielding film Table 2 shows the results.

  From the results shown in Table 2, it can be seen that the infrared shielding film sample of the present invention has high visible light transmittance, low infrared transmittance, and high coating strength even after repeated temperature and humidity changes.

Example 2
<Production of infrared shielding film>
[Preparation of Infrared Shielding Film Samples 201 to 202]
In preparation of the sample 103 of Example 1, instead of 10.3 parts of 5.0% by weight aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.) when preparing the coating liquid H1 for the high refractive index layer, As shown in Table 3, Samples 201 and 202 were produced in the same manner except that 10.3 parts of 5.0 wt% aqueous solutions of modified polyvinyl alcohol HPVA1 and HPVA2 were used.

<Evaluation of infrared shielding film>
Subsequently, the infrared shielding film samples 201 to 202 produced above were evaluated in the same manner as described in Example 1 for visible light transmittance, near infrared transmittance, and durability. As a result, it was confirmed that the same effects as those of the sample 103 described in Example 1 were obtained.

Example 3
<Production of infrared shielding body>
[Production of Infrared Shields 301-306]
The infrared shielding films of Samples 103 to 108 produced in Example 1 were adhered to a transparent acrylic resin plate having a thickness of 5 mm and 20 cm × 20 cm with an acrylic adhesive to produce infrared shielding bodies 301 to 306. did.
<Evaluation of infrared shielding material>
The infrared shields 301 to 306 of the present invention produced above can be easily used even though the size of the infrared shield is large, and by using the infrared shield film of the present invention. Excellent infrared shielding properties could be confirmed.

Claims (9)

On the substrate
Having at least one unit composed of a high refractive index layer and a low refractive index layer containing a binder resin and metal oxide particles,
The refractive index difference between the high refractive index layer and the low refractive index layer is 0.1 or more,
At least one of the high refractive index layer or the low refractive index layer is, as the binder resin , (1) unmodified polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less, or modified by cation modification, anion modification or nonion modification. A copolymer obtained by copolymerizing polyvinyl alcohol and (2) one or more polymerizable vinyl monomers selected from the group consisting of unsaturated carboxylic acids and salts and esters thereof. , Infrared shielding film. The copolymer is (1) one or more polymerizable vinyls selected from the group consisting of polyvinyl alcohol having an average degree of polymerization of 200 or more and 2400 or less, and (2) unsaturated carboxylic acid and salts and esters thereof. The infrared shielding film of Claim 1 which is a copolymer obtained by copolymerizing a monomer with the mass ratio of 0.5: 9.5-9.5: 0.5. The polymerizable vinyl polymer is acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid and salts thereof, and the following general formula (I):
In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 4 carbon atoms,
The infrared shielding film of Claim 2 which is 1 type, or 2 or more types selected from the group which consists of unsaturated carboxylic acid ester represented by these.   The infrared shielding film according to claim 3, wherein the polymerizable vinyl monomer is acrylic acid or a salt thereof and / or methyl methacrylate.   The polymerizable vinyl monomer is a mixture of acrylic acid or a salt thereof and methyl methacrylate, and a weight ratio of acrylic acid or a salt thereof to methyl methacrylate is from 3: 7 to 0.5: 9.5 (acrylic acid). Or the salt thereof: methyl methacrylate).   The infrared shielding film of any one of Claims 1-5 whose content rate of the said modified polyvinyl alcohol is 5-45 mass% with respect to the said binder resin.   The infrared shielding film according to claim 1, wherein at least one of the high refractive index layer or the low refractive index layer contains boric acid and a salt thereof and / or borax.   The infrared shielding film of any one of Claims 1-7 in which the said high refractive index layer contains a rutile type titania.   The infrared shielding body which provided the infrared shielding film of any one of Claims 1-8 in the at least one surface of the base | substrate.