WO2016010049A1 - Laminated film and method for producing same - Google Patents

Abstract

　The present invention pertains to a laminated film: comprising a substrate, and an infrared light absorbing layer that is disposed on one surface of the substrate and contains an infrared light absorbing agent and a resin; and having a total concentration of iron, copper and chromium contained in the infrared light absorbing layer of 1 to 500 ppm. The present invention enables a laminated film having a layer containing an infrared absorbing agent to be provided, wherein there is little cracking even after long-term exposure to sunlight.

Description

Laminated film and method for producing the same

The present invention relates to a laminated film and a method for producing the same.

In general, a laminated film in which a high refractive index layer and a low refractive index layer are alternately laminated by adjusting the respective optical film thicknesses is theoretically supported by selectively reflecting light of a specific wavelength, It is used as a laminated film that transmits visible light and selectively reflects near infrared rays. Such a laminated film is used as a reflective film for heat ray shielding used for windows of buildings, members for vehicles, and the like.

However, in the infrared (heat ray) shielding film in which such a heat ray reflective film is formed on the film, it may be difficult to sufficiently shield the infrared region with only the laminated film in consideration of productivity and optical characteristics. . With respect to such problems, it is possible to correct transmitted light by providing a layer mixed with an infrared absorbent having infrared absorbing ability in the film. As a technique as described above, for example, in Japanese translations of PCT publication No. 2008-528313 (corresponding to US Patent Application Publication No. 2006/154049), a red film in which a first polymer layer and a second polymer layer are alternately laminated is disclosed. An infrared reflective multilayer film comprising an outer reflective layer and an infrared light absorbing nanoparticle layer laminated adjacently on the infrared reflective layer is proposed. Here, the infrared light absorbing nanoparticle layer is an antimony-doped tin oxide (also referred to as antimony-doped tin oxide; hereinafter referred to as ATO) or indium tin oxide (also referred to as indium-doped tin oxide) which is an infrared absorber. ) Etc.

A multilayer film having a high effect of shielding infrared rays by providing an infrared light-absorbing nanoparticle layer containing an infrared absorber as disclosed in JP-T-2008-528313 (corresponding to US Patent Application Publication No. 2006/154049) Is provided.

However, as described in Japanese Patent Application Publication No. 2008-528313 (corresponding to US Patent Application Publication No. 2006/154049), the present inventors have been able to apply an infrared light absorbing nanoparticle layer containing an infrared absorber to sunlight for a long time. It has been found that when exposed, discoloration and cracking (cracking) occur and haze deteriorates.

Accordingly, an object of the present invention is made in view of the above circumstances, and in a laminated film having a layer containing an infrared absorber, even if it is exposed to sunlight for a long period of time, it is a laminated film with less occurrence of cracks. To provide a film. Another object of the present invention is to provide a laminated film that has a layer containing an infrared absorber and that does not easily discolor even when exposed to sunlight for a long period of time. Still another object of the present invention is to provide a laminated film having a layer containing an infrared absorber and capable of reducing haze even when exposed to sunlight for a long period of time.

As a result of intensive studies to solve the above problems, the present inventors have found that the object of the present invention can be achieved by adopting the following configuration.

That is, the above-mentioned problem of the present invention is solved by the following means.

1. A base material, and an infrared absorption layer containing an infrared absorber and a resin, disposed on one surface of the base material,
A laminated film in which the total concentration of iron, copper and chromium contained in the infrared absorbing layer is 1 to 500 ppm;
2. In the infrared absorbing layer, the total concentration of the iron, copper and chromium with respect to the infrared absorbing agent is 100 to 26000 ppm. A laminated film according to claim 1;
3. The infrared absorption layer further includes a surfactant, and the total concentration of the iron, copper, and chromium with respect to the surfactant in the infrared absorption layer is more than 0.3% by mass and less than 160% by mass. 1. Or 2. A laminated film according to claim 1;
4). The infrared absorber is antimony-doped tin oxide, indium-doped tin oxide, cesium-doped tungsten oxide, lanthanum hexaboride, antimony-doped zinc oxide, indium-doped zinc oxide, conductive polymer, conductive carbon material 1. At least one selected from the group consisting of ~ 3. A laminated film according to any one of the above;
5. Further comprising a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately laminated,
1. The low refractive index layer or the high refractive index layer contains metal oxide particles. ~ 4. A laminated film according to any one of the above;
6). A method for producing a laminated film having an infrared absorbing layer containing an infrared absorbent and a resin on one surface of a substrate,
A method for producing a laminated film, comprising a step of preparing a coating solution so that a total concentration of iron, copper and chromium contained in the infrared absorbing layer is 1 to 500 ppm.

Hereinafter, embodiments of the present invention will be described.

According to a first aspect of the present invention, the base material and an infrared absorption layer containing an infrared absorber and a resin disposed on one surface of the base material, the infrared absorption layer A laminated film having a total concentration of iron, copper and chromium contained in 1 to 500 ppm is provided.

The laminated film according to the present invention has an infrared absorption layer containing an infrared absorber and a resin. Here, as described above, a laminated film having an infrared absorption layer containing an infrared absorber, as in the technique of JP-T-2008-528313 (corresponding to US Patent Application Publication No. 2006/154049), It has been found that when the laminated film is exposed to sunlight for a long period of time, discoloration and cracking occur and a haze problem occurs.

Therefore, the present inventors have studied as follows for the purpose of solving the above-mentioned problems of the laminated film.

First, the inventors examined the suppression of cracks in the laminated film. When the amount of the specific metal contained in the infrared absorption layer is large, the total concentration of the specific metal is particularly 500 ppm. It has been found that the tendency to become prominent is exceeded.

The crack in the infrared absorbing layer is explained by the following mechanism. First, in the configuration in which the specific metal and the resin coexist in the infrared absorption layer, the thermal conductivity of the metal and the resin is greatly different, so the degree of thermal expansion and contraction of the metal and the degree of thermal expansion and contraction of the resin Are very different. As a result, the infrared absorbing agent absorbs infrared rays and the infrared absorbing layer generates heat. If it does so, the interface of a metal and resin will become the starting point of the crack in the infrared rays absorption layer containing these by a temperature difference, and it will be thought that it becomes easy to generate | occur | produce a crack as a result. Therefore, from such a difference in the degree of thermal expansion and contraction, when there are many parts that are the starting points of cracks (that is, the concentration of the metal), particularly when the total concentration of the specific metal exceeds 500 ppm, It is assumed that cracks are likely to occur. On the other hand, in the laminated film according to the present invention, since the total concentration of the specific metal contained in the infrared absorption layer is 500 ppm or less, the starting point of the crack as described above hardly occurs. Therefore, according to the present invention, in a laminated film having a layer containing an infrared absorber, a laminated film with less occurrence of cracks even when exposed to sunlight for a long period of time is provided.

In addition, the specific metal promotes the photo-oxidation of the resin by sunlight, heat, and water, so that the haze of the film is deteriorated. Accordingly, when the total concentration of the specific metals exceeds 500 ppm, haze deterioration becomes a problem, but by setting it to 500 ppm or less, haze deterioration is effectively suppressed. Furthermore, if the total concentration of the specific metals is more than 500 ppm, the resin is salted out by the metals, so that the film is likely to be clouded. Therefore, also for the purpose of suppressing such salting out, the total concentration of the specific metal is preferably 500 ppm or less.

Furthermore, when the present inventors examined suppression of discoloration in a laminated film, surprisingly, iron, copper and chromium (also referred to as “specific metal” in this specification) contained in the infrared absorption layer are surprisingly found. It has been found that discoloration of the infrared absorption layer is suppressed by setting the total concentration to a certain value (specifically, 1 ppm) or more. The reason is not clear, but it is thought as follows.

It is presumed that the infrared absorbing agent contained in the infrared absorbing layer is exposed to sunlight for a long period of time, and as a result, the light absorption region is changed as a result of the change of the electronic state, and the infrared absorbing layer is colored. On the other hand, when a certain amount or more of the specific metal is contained in the infrared absorption layer, the specific metal interacts with the infrared absorber, and the infrared absorber is oxidized or reduced, whereby the infrared absorber. Can be maintained in a neutral state (state without charge). Therefore, if the above-mentioned specific metal is contained in the infrared absorbing layer in a predetermined amount or more, the electronic state of the infrared absorbing agent can be kept in the initial state, so that the infrared absorbing layer can be effectively colored. It is thought that it can be suppressed.

Therefore, from the above, by making the total concentration of the specific metal in the infrared absorbing layer in the above range (1 to 500 ppm), the occurrence of cracks is suppressed, and discoloration of the infrared absorbing layer is also suppressed. It is considered that haze deterioration is also effectively reduced. Note that the mechanism for exerting the action effect by the configuration of the present invention described above is speculation, and the present invention is not limited by the above speculation.

Hereinafter, components of the laminated film of the present invention will be described in detail. Hereinafter, when the low refractive index layer and the high refractive index layer are not distinguished, the concept including both is referred to as a “refractive index layer”.

In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%.

[Laminated film]
The laminated film which concerns on this invention has a base material and the infrared rays absorption layer arrange | positioned on the one surface of the said base material. The infrared absorbing layer may be disposed adjacent to the substrate, or another layer (functional layer) may be interposed between the substrate and the infrared absorbing layer. Moreover, it is preferable that an infrared absorption layer is arrange | positioned in the surface into which light injects from viewpoints, such as durability of the other layer contained in a laminated film.

One feature of the laminated film of the present invention is that it has an infrared absorption layer, and the total concentration of iron, copper and chromium contained in the infrared absorption layer is 1 to 500 ppm. Below, an infrared absorption layer is explained in full detail first. In the present specification, “ppm” refers to a concentration based on mass (mass ppm).

[Infrared absorbing layer]
Since the laminated film according to the present invention has an infrared absorption layer, an infrared shielding effect is imparted, and the infrared shielding effect can be improved. The infrared absorbing layer is a layer having the ability to absorb light in the near infrared region having a wavelength of 800 to 2500 nm, and includes an infrared absorbing agent, a resin, and specific metals (iron, copper, and chromium). The infrared absorbing layer may contain other additives in order to impart other functions or improve various properties.

In the laminated film according to the present invention, specific metals (iron, copper and chromium) contained in the infrared absorbing layer have a total concentration of 1 to 500 ppm. That is, the infrared absorbing layer contains 1 to 500 ppm of these specific metals with respect to the total mass of the total solid content of the infrared absorbing layer. In the present specification, the concentration of the specific metal refers to a value measured using an ICP-AES (inductively coupled plasma emission spectrometer), and a specific measurement method is the method described in the examples. Shall be followed.

In the present invention, the total concentration of iron, copper and chromium may be in the above range, and the infrared absorbing layer may contain only one kind of these metals, or two or more kinds thereof. The aspect which an infrared rays absorption layer contains may be sufficient. That is, in the present invention, the infrared absorption layer contains at least one metal selected from the group consisting of iron, copper and chromium, and the total concentration range of the metal is 1 to 500 ppm. Therefore, for example, the infrared absorption layer may contain only iron and copper, and may contain only chromium, or may contain no iron and contain copper and chromium. Moreover, when 2 or more types of metals are included, the ratio (mass ratio) is not specifically limited.

Here, from the viewpoint of suppressing discoloration, the infrared absorption layer preferably contains Fe among the above-mentioned specific metals. Fe is particularly easy to interact with an infrared absorber in terms of energy, and has a high effect of suppressing coloring. In addition, since Fe has a thermal conductivity close to that of resin (resin contained in the infrared absorption layer) compared to other metals, cracking due to thermal expansion and contraction is suppressed while suppressing coloring of the infrared absorption layer. Can be suppressed.

In order to obtain all the effects of suppressing discoloration and cracking and reducing haze in a well-balanced manner, the specific concentration of the specific metals (iron, copper and chromium) contained in the infrared absorption layer is preferably 50 to 500 ppm. 60 to 450 ppm, more preferably 70 to 400 ppm, even more preferably 80 to 350 ppm, and particularly preferably 100 to 300 ppm.

The thickness of the infrared absorbing layer is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 1 μm to 20 μm, still more preferably 3 to 15 μm, and particularly preferably 3 to 10 μm. If it is 0.1 μm or more, the infrared absorption ability tends to be improved. On the other hand, if it is 20 μm or less, more preferably 15 μm or less, and further preferably 10 μm or less, the crack resistance of the coating film is improved. Further, by setting the thickness to 0.1 μm to 20 μm, more preferably 0.1 to 10 μm, a haze reduction effect can be obtained, and the discoloration suppression effect can be further improved while suppressing the occurrence of cracks. Can do.

In addition, although the formation method of an infrared rays absorption layer is explained in full detail below, an infrared rays absorption layer is a coating liquid (usually containing the infrared absorber and resin which are explained in full detail below with a specific metal (iron, copper, and chromium). Any of a coating film coated with an aqueous solvent such as water), a coating film coated with a coating solution containing an organic solvent-soluble resin (usually including an organic solvent), and a coating film of a solventless resin composition But you can.

(Infrared absorber)
In the present invention, the infrared absorption layer contains an infrared absorber. Here, the “infrared absorber” is not particularly limited as long as it is more excellent in infrared absorbing ability than the resin material constituting the laminated film, and is generally used by adding to a transparent resin. Can be used. Here, as an infrared absorber, a light transmittance of a wavelength of 550 nm is obtained in a part or all of a near infrared wavelength region of 800 to 2500 nm in a solution in which 1 part by mass of a compound is dissolved / dispersed in 100 parts by mass of a good solvent. Compounds that are 50% or less, more preferably 30% or less, are preferred.

When the infrared absorbing layer contains an infrared absorbing agent, the infrared absorbing layer absorbs infrared rays. At this time, since the infrared absorbing agent absorbs infrared rays and generates heat (heat storage), the infrared absorbing layer is particularly likely to have a high temperature. . Therefore, when metals other than infrared absorbers (especially iron, copper and chromium) are contained in the infrared absorbing layer, the influence of the difference in the degree of thermal expansion and contraction between these metals and the resin constituting the infrared absorbing layer. Is particularly large, and cracks are likely to occur. However, according to the present invention, the occurrence of such cracks can be effectively suppressed by setting the total concentration of the specific metals (iron, copper and chromium) to 1 to 500 ppm.

In addition, infrared absorbers are exposed to excessive energy when exposed to sunlight for a long period of time. As a result, the electronic state changes, the light absorption characteristics change, and the film is colored. It becomes. However, when 1 ppm or more of the specific metals (iron, copper, and chromium) is contained, these metals contribute to the redox of the infrared absorber, and the electronic state of the infrared absorber is easily maintained in the initial state. Therefore, coloring is also suppressed.

The infrared absorbent contained in the infrared absorbing layer is not particularly limited, and may be an inorganic infrared absorbent or an organic infrared absorbent.

Examples of inorganic infrared absorbers that can be contained in the infrared absorbing layer include tin oxide, antimony-doped tin oxide (ATO), indium-doped tin oxide (ITO), cesium-doped tungsten oxide (CWO), and lanthanum hexaboride (LaB). ₆ ), zinc oxide, antimony-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide, and nickel complex compounds.

In addition, specific names of these products include zinc oxide-based, Celnax series (manufactured by Nissan Chemical Industries), and passette series (manufactured by Hakusuitec); tin oxide-based, ATO dispersion (SR35M Advanced Nano Products) Co., Ltd.), ITO dispersion (Mitsubishi Materials Electronics Kasei Co., Ltd.), KH series (Sumitomo Metal Mining); CWO dispersion as cesium doped tungsten oxide (YMF-02A, Sumitomo Metal Mining); Examples of lanthanum include LaB ₆ dispersion (KHF-7AH, manufactured by Sumitomo Metal Mining Co., Ltd.). In addition, as an inorganic infrared absorber, in order to control easily the density | concentration (content) of iron, copper, and chromium in an infrared rays absorption layer, what does not contain these specific metals is preferable.

Further, as an inorganic infrared _{absorber, Cd / Se, GaN, Y} 2 O 3, Au, may also be used those made of Ag.

The average particle size of the inorganic infrared absorber is preferably 5 to 150 nm, more preferably 10 to 120 nm. By setting it to 5 nm or more, the dispersibility in the resin and the infrared absorptivity are satisfactorily maintained, and by setting the thickness to 150 nm or less, a decrease in visible light transmittance can be suppressed. In addition, the measurement of an average particle diameter is image | photographed with a transmission electron microscope, extracts 50 particle | grains at random, measures this particle diameter, and averages this. Moreover, when the shape of particle | grains is not spherical, it defines as what was calculated by measuring a major axis.

Organic infrared absorbers that can be contained in the infrared absorbing layer include conductive polymers such as polyacetylene compounds, polyparaphenylene compounds, polyphenylene vinylene compounds, polypyrrole, polythiophene compounds, PEDOT-PSS; imonium compounds; phthalocyanine compounds (however, the center Metals other than iron, copper, and chromium are preferred); and conductive carbon materials such as carbon nanotubes, acetylene black, ketjen black (registered trademark), and carbon black.

Specific product names of these include Denatoron P-502S, P-502RG, Denattron PT-432, NIR-IM1, NIR-AM1 (manufactured by Nagase ChemteX Corporation), Clevios CPP 105D, CPP 134.18D, CPP141D, CPG130.6 (manufactured by Heraeus), SEPLEGYDA series (manufactured by Shin-Etsu Polymer), Lumogen series (manufactured by BASF) and the like.

Among the above, from the viewpoint of dispersibility in the infrared absorbing layer, infrared absorbing ability, and the like, the infrared absorbing agent is antimony-doped tin oxide, indium-doped tin oxide, cesium-doped tungsten oxide, hexaboronated lanthanum, antimony-doped. It is preferable that it is 1 type, or 2 or more types selected from the group which consists of zinc trioxide, indium dope zinc oxide, a conductive polymer, and a conductive carbon material.

In addition, the said infrared absorber can be used individually or in combination of 2 or more types.

Here, among the various conductive polymers described above, a polythiophene compound and PEDOT-PSS are preferable from the viewpoint of high visible light transmittance.

The content of the infrared absorbent in the infrared absorbing layer is not particularly limited, but from the viewpoint of adjusting the physical properties such as film strength and film elastic modulus and optical properties such as transmittance to the desired value, the total mass of the infrared absorbing layer (In terms of solid content when the total mass of the infrared absorbing layer is 100% by mass), preferably 0.1 to 80% by mass, more preferably 1 to 80% by mass, It is especially preferable that it is 70 mass%. If the content is 0.1% or more, a sufficient infrared absorption effect can be obtained, and if it is 80% by mass or less, a sufficient amount of visible light can be transmitted.

In addition, as described above, in the present invention, when the specific metal (iron, copper, and chromium) contained in the infrared absorption layer interacts with the infrared absorber, the coloring suppression effect is exhibited. Guessed. Therefore, the coloring suppression effect can be further improved by appropriately adjusting the content of the infrared absorbing agent in the infrared absorbing layer and the content of the specific metal. At this time, the content of the infrared absorbing agent in the infrared absorbing layer and the content of the specific metal are preferably in the following relationship. That is, the total concentration of iron, copper and chromium with respect to the infrared absorber in the infrared absorbing layer is preferably 100 to 26000 ppm. If it is 100 ppm or more, it is preferable because the coloration suppressing effect can be improved, and if it is 26000 ppm or less, it is preferable in terms of suppressing discoloration.

In order to further improve the above effects, the total concentration is more preferably 200 to 10000 ppm, and particularly preferably 200 to 1000 ppm.

(resin)
In this invention, an infrared rays absorption layer contains resin with the said infrared absorber. As the resin, either a water-soluble resin or an organic solvent-soluble resin can be used.

From the viewpoint of reducing environmental load and process load, it is preferable to contain a water-soluble resin. The water-soluble resin is not particularly limited, and examples thereof include polyvinyl alcohol resins, gelatin, celluloses, thickening polysaccharides, and polymers having reactive functional groups. In this specification, “water-soluble” means a G2 glass filter (maximum pores 40 to 50 μm) when dissolved in water so as to have a concentration of 0.5% by mass at the temperature at which the substance is most dissolved. This means that the mass of insoluble matter to be filtered out is within 50% by mass of the added polymer.

On the other hand, it is preferable to contain an organic solvent-soluble resin from the viewpoint that the influence of humidity fluctuation of the film is reduced. The organic solvent-soluble resin is not particularly limited, but acrylic resin, urethane-modified acrylic resin, polyurethane resin, polyester resin, melamine resin, polyvinyl acetate, cellulose acetate, polycarbonate, polyacetal, polybutyral, polyamide (nylon) resin, polystyrene Examples thereof include resins, polyimide resins, ABS resins, polyvinylidene fluoride, and ultraviolet curable resins.

Examples of the ultraviolet curable resin include (meth) acrylate, urethane acrylate, polyester acrylate, epoxy acrylate, epoxy resin, and oxetane resin, and these can also be used as a solvent-free resin composition.

When using the ultraviolet curable resin, it is preferable to add a photopolymerization initiator to accelerate curing.

Photoinitiators include acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoroamine compounds Etc. are used. Specific examples of the photopolymerization initiator include 2,2′-diethoxyacetophenone, 2,4-dimethylacetophenone, p-methylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 1-hydroxydimethylphenyl ketone, 2-methyl-4 Acetophenones such as' -methylthio-2-morpholinopropiophenone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl Benzoins such as ether and benzyldimethylletal, benzophenone, 2,4'-dichlorobenzophenone, benzophenones such as 4,4'-dichlorobenzophenone and p-chlorobenzophenone, 2,4,6-trimethylbenzoyldiph Cycloalkenyl phosphine oxide, anthraquinones, and the like thioxanthones. These photopolymerization initiators may be used alone, in combination of two or more, or in a eutectic mixture. In particular, acetophenones are preferably used from the viewpoints of stability of the curable composition and polymerization reactivity.

Commercially available products may be used as such a photopolymerization initiator, and preferred examples include Irgacure (registered trademark) 819, 184, 907, 651 manufactured by BASF Japan.

Depending on the type of resin constituting the infrared absorbing layer, the infrared absorbing layer can be provided with scratch resistance (hard coat property). Therefore, the infrared absorbing layer also serves as a hard coat layer described later. May be. For example, by using the ultraviolet curable resin, hard coat properties can be imparted to the infrared absorbing layer. Here, the hard coat property means that the pencil hardness according to JIS K 5600-5-4: 1999 is H or more, preferably 2H or more. The hardness of the hard coat is preferably in terms of scratch resistance as long as the layer is not damaged or peeled off when an external stress such as bending is applied.

As described above, in the present invention, the infrared absorbing layer contains the specific metal (iron, copper and chromium), and the total concentration of iron, copper and chromium with respect to the resin is preferably 1 to 1000 ppm. More preferably, it is ˜300 ppm.

(Surfactant)
In addition to the specific metals (iron, copper and chromium), the infrared absorber and the resin, it is preferable to add a surfactant to the infrared absorbing layer for the purpose of exerting a function as a leveling agent or a slipping agent. .

The surfactant is not particularly limited, and examples include zwitterionic surfactants, cationic surfactants, anionic surfactants, nonionic surfactants, fluorosurfactants and silicon surfactants. . Of these, acrylic surfactants, silicon surfactants, or fluorosurfactants are preferred, and fluorosurfactants are particularly preferred from the viewpoint of the uniformity and appearance of the coating film surface. As the surfactant, a surfactant containing a long-chain alkyl group is preferable, and a surfactant having an alkyl group having 6 to 20 carbon atoms is more preferable.

Zwitterionic surfactants include alkylbetaines, alkylamine oxides, cocamidopropyl betaines, lauramidopropyl betaines, palm kernel fatty acid amidopropyl betaines, cocoamphoacetic acid N, lauroamphoacetic acid Na, lauramidopropyl hydroxysultains, lauramide Examples include propylamine oxide, myristamidopropylamine oxide, hydroxyalkyl (C12-14) hydroxyethyl sarcosine.

Examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts.

Examples of the anionic surfactant include alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, alkylbenzene sulfonate, fatty acid salt, polyoxyethylene alkyl ether phosphate, and dipotassium alkenyl succinate.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether (for example, Emulgen manufactured by Kao), polyoxyethylene sorbitan fatty acid ester (for example, Leodol TW series manufactured by Kao), glycerin fatty acid ester, polyoxyethylene fatty acid ester, poly Examples thereof include oxyethylene alkylamine and alkyl alkanolamide.

Fluorosurfactants include Surflon S-211, S-221, S-231, S-241, S-242, S-243, S-420 (manufactured by AGC Seimi Chemical Co., Ltd.), Megafac F-114, Examples thereof include F-410, F-477, F-552, F-553 (manufactured by DIC), FC-430, FC-4430, and FC-4432 (manufactured by 3M).

Examples of silicon-based surfactants include BYK-345, BYK-347, BYK-348, and BYK-349 (manufactured by Big Chemie Japan).

In addition, the said surfactant can be used individually or in combination of 2 or more types.

The content of the surfactant in the infrared absorbing layer is not particularly limited, but for the purpose of sufficiently obtaining the function as a leveling agent or a slipping agent, when the total mass of the infrared absorbing layer coating liquid is 100% by mass, The range is preferably 0.001 to 0.30% by mass, and more preferably 0.005 to 0.10% by mass.

The content of the surfactant is preferably in the range of 0.005 to 5% by mass with respect to the total mass of the infrared absorption layer (when the total mass of the infrared absorption layer is 100% by mass). More preferably, the content is 0.01 to 3% by mass.

In a more preferred embodiment of the present invention, the infrared absorption layer preferably further contains a surfactant. At this time, it is preferable in the infrared absorption layer that the total concentration of iron, copper and chromium with respect to the surfactant is more than 0.3% by mass and less than 160% by mass.

When the concentration exceeds 0.3% by mass, cracks are less likely to occur, and when it is less than 160% by mass, it is preferable from the viewpoint of suppressing discoloration. Further, the concentration is preferably 4% by mass to less than 160% by mass, more preferably 10% by mass to 150% by mass, still more preferably 20% by mass to 145% by mass, and even more preferably 30% by mass to 100% by mass. Is particularly preferred.

(Other additives)
As described above, the infrared absorption layer preferably contains a surfactant in addition to the specific metal (iron, copper and chromium), the infrared absorber and the resin, but unless the effects of the present invention are impaired. Further, other additives may be included.

For example, the infrared absorption layer may contain inorganic nanoparticles as other additives. By including the inorganic nanoparticles, when the infrared absorption layer is disposed adjacent to the substrate, the adhesion to the substrate is improved, and the scratch resistance of the laminated film can be improved. In the present specification, the “inorganic nanoparticles” mean particles made of an inorganic compound (preferably inorganic oxide) having an average particle diameter measured by a dynamic scattering method of 200 nm or less.

There is no particular limitation on the specific composition of the inorganic nanoparticles, _SiO 2 is a metal oxide which can be used in the dielectric multilayer film to be described _{below, Al 2 O 3, ZrO 2} , TiO 2, CeO 2 , etc. Can be used.

The content of the inorganic nanoparticles in the infrared absorbing layer is not particularly limited, but is preferably 10 to 80 mass from the viewpoint of adjusting physical properties such as surface hardness and film elastic modulus and optical properties such as transmittance to desired values. %, More preferably 20 to 65% by mass.

(Method for forming infrared absorbing layer)
The method for forming the infrared absorbing layer is not particularly limited as long as the infrared absorbing layer having a total concentration of iron, copper, and chromium contained in the layer of 1 to 500 ppm can be formed. It is preferable to use a method (wet method) in which an infrared absorbing layer coating solution for forming the infrared absorbing layer is prepared in advance and applied.

Therefore, according to the 2nd form of this invention, it is a manufacturing method of the laminated | multilayer film which has an infrared rays absorption layer containing an infrared absorber and resin on one surface of a base material, Comprising: It is contained in an infrared rays absorption layer There is also provided a method for producing a laminated film including a step of preparing a coating solution so that the total concentration of iron, copper and chromium is 1 to 500 ppm.

Thus, by preparing the infrared absorbing layer coating solution so that the total concentration of the specific metal (iron, copper and chromium) is 1 to 500 ppm with respect to the total solid mass of the infrared absorbing layer, It becomes easy to disperse the specific metals (iron, copper and chromium) contained in the infrared absorbing layer and the infrared absorbing agent uniformly in advance. As a result, the formed infrared absorption layer not only has a high discoloration suppressing effect, but also has a high haze reduction effect.

The method for preparing the infrared absorbing layer coating solution is not particularly limited as long as the total concentration of the specific metal can be 1 to 500 ppm with respect to the total solid content in the coating solution. The infrared absorbing layer coating liquid can be prepared, for example, by adding an infrared absorbent, a resin, and other additives such as a surfactant used as necessary to a solvent, and stirring and mixing. 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.

Here, in order to make the total concentration of the specific metal within the above range, the following steps are preferably performed.

That is, first, an infrared absorption layer coating solution is prepared by mixing a solvent, an infrared absorber, a resin, and various additives that are added as necessary, and then the total solid mass contained in the coating solution It is preferable that the step of measuring the total concentration of the specific metal is performed. And when the total density | concentration of the said specific metal is less than a minimum (that is, less than 1 ppm), the said specific metal is added suitably. On the other hand, when the total concentration of the specific metal exceeds the upper limit (that is, more than 500 ppm), a step of removing the specific metal by a method such as ultrafiltration and / or a solid component such as a resin in the solution It is preferable to further add and to dilute the specific metal concentration. At this time, as a method for removing the specific metal, a method such as ultrafiltration can be used.

In particular, between the preparation of the infrared absorbing layer coating solution and the coating, equipment that contacts the coating solution (for example, piping used to transport the coating solution to a coating device such as a gravure coater, or a container for preparing the coating solution) Etc.) may contain iron, chromium, etc. contained in the SUS due to contact between the coating liquid and SUS. As a result, the total concentration of the specific metals tends to exceed 500 ppm. Therefore, when preparing the infrared absorbing layer coating solution, it is preferable to measure the total concentration of the specific metal immediately before coating.

As described above, when the infrared absorbing layer coating liquid is transported via a pipe containing SUS, the total concentration of the specific metal tends to increase as the transport time (coating liquid circulation time) increases. is there. Therefore, in order to reduce the total concentration of the specific metal, a method of shortening the circulation time of the infrared absorbing layer coating solution, or a method of covering the surface in the pipe with a material not containing the specific metal, etc. The method is taken. At this time, the covering material for covering the surface in the pipe is not particularly limited, and any material can be suitably used as long as the material does not include the specific metal. Specifically, a fluororesin coat such as a glass coat, a silicon coat, and Teflon (registered trademark, hereinafter the same) can be used.

On the other hand, in order to increase the specific metal concentration, it is preferable to increase the circulation time of the infrared absorbing layer coating solution. In order to set the specific metal concentration to 1 to 500 ppm relative to the mass of the total solid content contained in the infrared absorbing layer coating liquid, for example, when a SUS pipe with no surface coating is used, the circulation time of the coating liquid Is preferably 0.5 to 15 hours, more preferably 1 to 10 hours, and particularly preferably 2 to 10 hours. By setting the circulation time within the above range, the metal concentration in the infrared absorbing layer can be 1 to 500 ppm by applying the infrared absorbing layer coating liquid as it is without further adding / removing the specific metal. It can be. Further, the concentration of the specific metal in the infrared absorbing layer coating solution can be controlled by the flow rate of the coating solution, the piping material, the coating solution concentration, and the like.

Therefore, as described above, the method for producing a laminated film according to the present invention includes a step of measuring the total concentration of iron, copper and chromium with respect to the total solid mass in the infrared absorbing layer coating solution (concentration measuring step). It is preferable that And in the said density | concentration measurement process, when the total density | concentration of the said specific metal is less than predetermined value (1 ppm), at least 1 type of metal selected from the group which consists of iron, copper, and chromium is added (addition process) On the other hand, when it exceeds a predetermined value (500 ppm), it is preferable that a step of removing these specific metals (removal step) is further performed. And the process of apply | coating a coating liquid is performed after the total density | concentration of the said specific metal becomes a preferable range (application | coating process). In addition, when there is a possibility that the specific metal is mixed due to the contact between the equipment used in the coating step and the infrared absorbing layer coating solution, the result obtained in the concentration measurement step is The process of adding or removing a specific metal is performed in consideration of the amount of the metal mixed in.

The solvent used in the infrared absorbing layer coating solution is not particularly limited as long as it can sufficiently disperse the resin and the infrared absorbing agent, and various organic solvents and aqueous solvents can be used.

The organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, n-propanol and i-propanol, esters such as ethyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, diethyl ether and propylene glycol. Examples include ethers such as monomethyl ether, amides such as dimethylformamide, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. These organic solvents may be used alone or in combination of two or more. Among the organic solvents, in view of the dispersibility of the resin and the infrared absorber, it is preferable to use esters, ethers, and ketones, and it is more preferable to use ketones.

The aqueous solvent is not particularly limited, and includes water or a mixed solvent of water and methanol, ethanol, n-propanol, i-propanol, or ethyl acetate. Among the above aqueous solvents, a mixed solvent of water and methanol, ethanol, n-propanol, or i-propanol is particularly preferable in consideration of the dispersibility of the resin and the infrared absorber.

When using a mixed solvent of water and a small amount of an organic solvent, the content of water in the mixed solvent is preferably 10 to 60% by mass, based on 100% by mass of the entire mixed solvent, and 20 to 50% by mass. It is more preferable that

The concentration of the resin in the infrared absorbing layer coating solution (when using a plurality of types of resins, the total concentration) is preferably 0.1 to 80% by mass, more preferably 0.3 to 50% by mass. 0.5 to 30% by mass is particularly preferable. The concentration of the infrared absorber in the infrared absorbing layer coating solution is preferably 0.1 to 50% by mass, and more preferably 0.15 to 30% by mass.

As described above, it is preferable that the infrared absorbing layer contains a surfactant. Accordingly, the surfactant is preferably added to the infrared absorbing layer coating solution, and the concentration of the surfactant in the infrared absorbing layer coating solution is preferably 0.005 to 0.30% by mass.

The infrared absorbing layer can be formed by applying the infrared absorbing layer coating solution prepared as described above. Here, the application method is not particularly limited, and for example, it can be formed by a wet method such as coating with a wire bar, spin coating, or dip coating. Moreover, it is also possible to apply and form a film using a continuous coating apparatus such as a die coater, a gravure coater, or a comma coater.

The application and drying conditions of the infrared absorbing layer are not particularly limited, and an appropriate temperature and drying time can be employed to promote curing and crosslinking. In particular, when an ultraviolet curable resin is used as the resin, the irradiation wavelength, the illuminance, and the light amount of the ultraviolet light are also appropriately adjusted.

[Base material]
The laminated film according to the present invention includes a base material for supporting the infrared absorbing layer and other optionally provided layers (for example, a dielectric multilayer film). As the base material of the laminated film, various resin films can be used. Polyolefin film (polyethylene, polypropylene, etc.), polyester film (polyethylene terephthalate (PET), polyethylene naphthalate, etc.), polyvinyl chloride, cellulose acetate, etc. Can be used, and a polyester film is preferable. 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 components, from the viewpoints 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. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized 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 used in the present invention is preferably 10 to 300 μm, particularly 20 to 150 μm. In addition, two substrates may be stacked, and in this case, the type may be the same or different.

The base material preferably has a visible light region transmittance of 85% or more shown in JIS R3106-1998, and particularly preferably 90% or more. When the base material has the above transmittance or more, it is advantageous in that the transmittance in the visible light region shown in JIS R3106-1998 is 50% or more (upper limit: 100%) when a laminated film is formed. preferable.

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

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

[Dielectric multilayer film]
The laminated film of the present invention reflects and shields at least a part of light when light having a specific wavelength (for example, infrared light) is incident (and thus heat shielding effect in the case of infrared light). ), It is preferable to further include a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately laminated. Here, the dielectric multilayer film may be provided on the opposite side of the infrared absorption layer via the base material, or may be provided on the same side as the infrared absorption layer on the base material.

In this embodiment, whether the refractive index layer constituting the dielectric multilayer film is a low refractive index layer or a high refractive index layer is determined by comparing the refractive index with the adjacent refractive index layer. Specifically, when a refractive index layer is used as a reference layer, if the refractive index layer adjacent to the reference layer has a lower refractive index than the reference layer, the reference layer is a high refractive index layer (the adjacent layer is a low refractive index layer). It is judged to be a rate layer. On the other hand, if the refractive index of the adjacent layer is higher than that of the reference layer, it is determined that the reference layer is a low refractive index layer (the adjacent layer is a high refractive index layer). Therefore, whether the refractive index layer is a high refractive index layer or a low refractive index layer is a relative one determined by the relationship with the refractive index of the adjacent layer. Depending on the relationship, it can be a high refractive index layer or a low refractive index layer.

Although there is no restriction | limiting in particular as a refractive index layer, Preferably it is preferable to use the well-known refractive index layer used in the said technical field. As a known refractive index layer, for example, a refractive index layer formed using a dry film forming method, a refractive index layer formed by extrusion molding of a resin, and a refractive index layer formed using a wet film forming method Is mentioned. Of these, the wet film forming method is preferably used from the viewpoint of production efficiency.

As described above, whether the layer is a low refractive index layer or a high refractive index layer is a relative one that is determined by the relationship with the adjacent refractive index layer. The structure of a typical high refractive index layer and low refractive index layer among refractive index layers that can be formed by a wet film forming method will be described below.

(Refractive index layer formed by wet film formation method)
In the wet film forming method, the refractive index layer can be formed by a method of sequentially applying and drying the coating solution, a method of applying and drying the coating solution in multiple layers, and the like. The refractive index layer of the laminated film according to the present embodiment is preferably formed by this wet film forming method, and more preferably formed by a method of applying and drying a coating solution in multiple layers.

-High refractive index layer-
The high refractive index layer preferably contains metal oxide particles from the viewpoint of easy control of the refractive index, and further contains a water-soluble resin, a curing agent, a surfactant, and other additives as necessary. You may go out. The metal oxide particles and the water-soluble resin contained in the high refractive index layer are hereinafter referred to as “first metal oxide particles” and “first water-soluble resin” for convenience.

(1) First Metal Oxide Particles The first metal oxide particles are not particularly limited, but are preferably metal oxide particles having a refractive index of 2.0 to 3.0. Specifically, titanium oxide, zirconium oxide, zinc oxide, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, ferric oxide, iron black, copper oxide, magnesium oxide, water Examples thereof include magnesium oxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Among these, the first metal oxide particles are preferably titanium oxide or zirconium oxide from the viewpoint of forming a transparent and high refractive index layer having a high refractive index. From the viewpoint of improving weather resistance, the first metal oxide particles are preferably a rutile type (tetragonal type). ) Titanium oxide is more preferable.

Further, the titanium oxide may be in the form of core / shell particles coated with a silicon-containing hydrated oxide. The core / shell particles have a structure in which the surface of the titanium oxide particles is coated with a shell made of a silicon-containing hydrated oxide on titanium oxide serving as a core.

The first metal oxide particles described above may be used alone or in combination of two or more.

The content of the first metal oxide particles is 15 to 85% by mass with respect to 100% by mass of the solid content of the high refractive index layer from the viewpoint of increasing the refractive index difference from the low refractive index layer. It is preferably 20 to 80% by mass, more preferably 30 to 77% by mass.

The first metal oxide particles preferably have a volume average particle size of 1 to 100 nm, and more preferably 3 to 50 nm. A volume average particle size of 100 nm or less is preferred because it has less haze and is excellent in visible light transmittance. In the present specification, the value measured by the following method is adopted as the value of “volume average particle diameter”. Specifically, arbitrary 1000 particles appearing on the cross section or surface of the refractive index layer are observed with an electron microscope to measure the particle size, and particles having particle sizes of d1, d2,. N1, n2,..., Ni, and nk of metal oxide particles, where the volume per particle is vi, the volume average particle diameter mv = {Σ (vi · di)} / The average particle diameter weighted by the volume represented by {Σ (vi)} is calculated.

(2) First water-soluble resin The first water-soluble resin is not particularly limited, but polyvinyl alcohol resins, gelatin, celluloses, thickening polysaccharides, and polymers having reactive functional groups can be used. . Of these, it is preferable to use a polyvinyl alcohol-based resin.

Polyvinyl alcohol resin As the polyvinyl alcohol resin, ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate (unmodified polyvinyl alcohol), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, vinyl alcohol Examples thereof include modified polyvinyl alcohol such as a polymer. The modified polyvinyl alcohol may improve the film adhesion, water resistance, and flexibility.

Gelatin As the gelatin, various gelatins that have been widely used in the field of silver halide photographic light-sensitive materials can be applied. For example, acid-treated gelatin, alkali-treated gelatin, enzyme-treated gelatin that undergoes enzyme treatment in the production process of gelatin, a group having an amino group, imino group, hydroxyl group, carboxyl group as a functional group in the molecule, and a group that can react with it And gelatin derivatives modified by treatment with a reagent having

When gelatin is used, a gelatin hardener can be added as necessary.

Cellulose As the cellulose, 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; carboxylic acid group-containing celluloses such as carboxymethyl cellulose (cellulose carboxymethyl ether) and carboxyethyl cellulose; Examples thereof include cellulose derivatives such as cellulose, cellulose acetate propionate, cellulose acetate, and cellulose sulfate.

Thickening polysaccharides Thickening polysaccharides are saccharide polymers that have many hydrogen bonding groups in the molecule. The thickening polysaccharide has a characteristic that the viscosity difference at low temperature and the viscosity at high temperature are large due to the difference in hydrogen bonding force between molecules depending on temperature. Further, when metal oxide fine particles are added to the thickening polysaccharide, the viscosity is increased due to hydrogen bonding with the metal oxide fine particles at a low temperature. As for the viscosity increase range, the viscosity at 15 ° C. is usually 1.0 mPa · s or more, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more.

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

Polymers having reactive functional groups Examples of polymers having reactive functional groups include polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, and vinyl acetate-acrylic esters. Acrylic resins such as copolymers, acrylic acid-acrylic acid ester copolymers; styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α -Styrene acrylic resins such as methylstyrene-acrylic acid copolymer and styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer; styrene-sodium styrenesulfonate copolymer, styrene-2-hydroxyethyl acrylate Copolymer, styrene -2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, And vinyl acetate-based copolymers such as vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer; and salts thereof. Of these, polyvinylpyrrolidones and copolymers containing the same are preferably used.

The above water-soluble resins may be used alone or in combination of two or more.

The weight average molecular weight of the first water-soluble resin is preferably 1000 to 200000, more preferably 3000 to 40000. In the present specification, the value measured by gel permeation chromatography (GPC) is adopted as the value of “weight average molecular weight”.

The content of the first water-soluble resin is preferably 5 to 50% by mass and more preferably 10 to 40% by mass with respect to 100% by mass of the solid content of the high refractive index layer.

(3) Curing Agent The curing agent has a function of reacting with the first water-soluble resin (preferably polyvinyl alcohol resin) contained in the high refractive index layer to form a hydrogen bond network.

The curing agent is not particularly limited as long as it causes a curing reaction with the first water-soluble resin, but in general, a compound having a group capable of reacting with the water-soluble resin or a different group possessed by the water-soluble resin. The compound which accelerates | stimulates mutual reaction is mentioned.

As a specific example, when polyvinyl alcohol is used as the first water-soluble resin, it is preferable to use boric acid and its salt as a curing agent. Moreover, you may use well-known hardening | curing agents other than boric acid and its salt.

In addition, boric acid and its salt mean oxygen acid and its salt having a boron atom as a central atom. Specific examples include orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octaboric acid, and salts thereof.

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

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

(4) Surfactant The surfactant that can be contained in the high refractive index layer is not particularly limited, but the same ones that can be added to the infrared absorbing layer can be used, and the detailed explanation thereof is as follows. Omitted.

(5) Other additives The high refractive index layer may also contain other additives. Examples of other additives include amino acids, emulsion resins, lithium compounds, and the like. Further, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, JP-A-62-261476; JP-A-57-74192, JP-A-57-87989 Japanese Patent Laid-Open No. 60-72785, Japanese Patent Laid-Open No. 61-146591, Japanese Patent Laid-Open No. 1-95091, Japanese Patent Laid-Open No. 3-13376, etc .; Japanese Patent Laid-Open No. 59-42993 Optical brighteners described in JP-A Nos. 59-52689, 62-280069, 61-242871, and 4-219266; sulfuric acid, phosphoric acid, PH adjusters such as acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate; antifoaming agents; lubricants such as diethylene glycol; antiseptics; antifungal agents; antistatic agents; matting agents; Antioxidant; flame retardants; crystal nucleating agent; inorganic particles; organic particles; viscosity reducers; lubricants; infrared absorber; dyes; known various additives such as a pigment or the like may be used as other additives.

-Low refractive index layer-
The low refractive index layer also preferably contains metal oxide particles from the viewpoint of easy control of the refractive index. In addition, a water-soluble resin, a curing agent, a surfactant, and other additives may be included as necessary. The metal oxide particles and the water-soluble resin contained in the low refractive index layer are hereinafter referred to as “second metal oxide particles” and “second water-soluble resin” for convenience.

(1) Second water-soluble resin As the second water-soluble resin, the same one as the first water-soluble resin can be used.

At this time, when the high refractive index layer and the low refractive index layer both use a polyvinyl alcohol-based resin as the first water-soluble resin and the second water-soluble resin, the polyvinyl alcohol-based resins having different degrees of saponification are used. It is preferable to use a resin. Thereby, mixing of the interface is suppressed, the infrared reflectance (infrared shielding rate) becomes better, and the haze can be lowered. In the present specification, the “degree of saponification” means the ratio of hydroxy groups to the total number of acetyloxy groups (derived from vinyl acetate as a raw material) and hydroxy groups in polyvinyl alcohol.

(2) Second metal oxide particles The second metal oxide particles are not particularly limited, but it is preferable to use silica (silicon dioxide) such as synthetic amorphous silica or colloidal silica, and acidic colloidal silica sol. It is more preferable to use Further, from the viewpoint of further reducing the refractive index, hollow fine particles having pores inside the particles can be used as the second metal oxide particles, and it is particularly preferable to use hollow fine particles of silica (silicon dioxide). .

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

The second metal oxide particles may be surface-coated with a surface coating component.

The second metal oxide particles (preferably silicon dioxide) contained in the low refractive index layer of the present invention preferably have an average particle size (number average; diameter) of 3 to 100 nm, preferably 3 to 50 nm. It is more preferable. In the present specification, the “average particle diameter (number average; diameter)” of the metal oxide fine particles is 1,000 particles observed by an electron microscope on the particles themselves or on the cross section or surface of the refractive index layer. The particle size of any of the particles is measured and determined 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 content of the second metal oxide particles in the low refractive index layer is preferably 0.1 to 85% by mass, and 30 to 80% by mass with respect to 100% by mass of the total solid content of the low refractive index layer. More preferred is 45 to 75% by mass.

The above-described second metal oxide may be used alone or in combination of two or more from the viewpoint of adjusting the refractive index.

(3) Curing Agent, Surfactant, and Other Additives As the curing agent, the surfactant, and other additives, the same materials as those for the high refractive index layer can be used, and thus the description thereof is omitted here.

In the dielectric multilayer film in which the high refractive index layer and the low refractive index layer having the above-described configuration are alternately laminated, at least one of the high refractive index layer and the low refractive index layer uses a wet film forming method. The refractive index layer is preferably formed, and both the high refractive index layer and the low refractive index layer are more preferably refractive index layers formed using a wet film forming method. Furthermore, it is preferable that at least one of the high refractive index layer and the low refractive index layer contains metal oxide particles. That is, the laminated film of the present invention further includes a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately laminated, and the low refractive index layer or the high refractive index layer contains metal oxide particles. It is preferable to include.

Furthermore, it is more preferable that both the high refractive index layer and the low refractive index layer contain metal oxide particles.

In the laminated film according to the present invention, it is preferable to design a large difference in refractive index between the low refractive index layer and the high refractive index layer from the viewpoint that the infrared reflectance can be increased with a small number of layers. In this embodiment, in at least one of the laminates composed of the low refractive index layer and the high refractive index layer, the difference in refractive index between the adjacent low refractive index layer and high refractive index layer may be 0.1 or more. Preferably, it is 0.3 or more. In the case of having a plurality of laminated bodies of high refractive index layers and low refractive index layers, it is preferable that the refractive index difference between the high refractive index layer and the low refractive index layer in all the laminated bodies is within the above-mentioned preferable range. However, even in this case, the refractive index layers constituting the uppermost layer and the lowermost layer of the dielectric multilayer film may have a configuration outside the above preferred range.

As the optical characteristics of the laminated film of this embodiment, the transmittance in the visible light region shown in JIS R3106-1998 is preferably 50% or more, preferably 75% or more, more preferably 85% or more, and the wavelength is 900 nm. It is preferable to have a region where the reflectance exceeds 50% in a region of ˜1400 nm.

The number of refractive index layers of the dielectric multilayer film (total number of high refractive index layers and low refractive index layers) is preferably 6 to 50 layers, and preferably 8 to 40 layers from the above viewpoint. More preferably, it is more preferably 11 to 31 layers, and particularly preferably 9 to 30 layers. It is preferable that the number of refractive index layers of the dielectric multilayer film is in the above range because excellent heat shielding performance and transparency, suppression of film peeling and cracking, and the like can be realized. When the dielectric multilayer film has a plurality of high refractive index layers and / or low refractive index layers, each high refractive index layer and / or each low refractive index layer is the same, but different. It may be a thing.

The thickness per layer of the high refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 500 nm. Further, the thickness per layer of the low refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 500 nm.

Here, when measuring the thickness per layer, the composition may change continuously without having a clear interface at the boundary between the high refractive index layer and the low refractive index layer. In such an interface region where the composition changes continuously, when the maximum refractive index−the minimum refractive index = Δn, the point of the minimum refractive index + Δn / 2 between the two layers is regarded as the layer interface.

When the high refractive index layer and the low refractive index layer contain metal oxide particles, the above composition can be observed from the concentration profile of the metal oxide particles. The metal oxide concentration profile is formed by etching from the surface to the depth direction using a sputtering method, and using an XPS surface analyzer, sputtering is performed at a rate of 0.5 nm / min, with the outermost surface being 0 nm. It can be seen by measuring the ratio. Further, the laminated film may be cut and the cut surface may be confirmed by measuring the atomic composition ratio with an XPS surface analyzer.

The XPS surface analyzer is not particularly limited, and any model can be used. As the XPS surface analyzer, for example, ESCALAB-200R manufactured by VG Scientific, Inc. can be used. Mg is used for the X-ray anode, and measurement is performed at an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA).

[Adhesive layer]
The laminated film according to the present invention may further have an adhesive layer. This pressure-sensitive adhesive layer is usually provided on the surface opposite to the infrared absorption layer via a substrate, and further known release paper (separator) may be further provided. The configuration of the adhesive layer is not particularly limited, and for example, any of a dry laminating agent, a wet laminating agent, an adhesive, a heat seal agent, a hot melt agent, and the like is used. As the adhesive, for example, a polyester resin, a urethane resin, a polyvinyl acetate resin, an acrylic resin, a nitrile rubber, or the like is used.

The layer thickness of the adhesive layer is preferably 1 μm to 100 μm, more preferably 3 to 50 μm. If it is 1 micrometer or more, there exists a tendency for adhesiveness to improve and sufficient adhesive force is acquired. Conversely, if it is 100 μm or less, not only the transparency of the laminated film is improved, but also after the laminated film is attached to the window glass, it does not cause cohesive failure between the adhesive layers when peeled off, and the adhesive remains on the glass surface Tend to disappear.

Although it does not restrict | limit especially as a formation method of an adhesion layer, Apart from the base material in which the said infrared absorption layer was formed, the coating liquid for adhesion layers was apply | coated and dried on the release paper (separator), and the adhesion layer was formed. Thereafter, a method in which the adhesive layer and the dielectric multilayer film or the substrate are bonded together is preferable.

[Hard coat layer]
The laminated film of the present invention has a hard coat layer containing a resin curable by heat, ultraviolet rays or the like on the uppermost layer on the side opposite to the side having the adhesive layer as a surface protective layer for enhancing the scratch resistance. You may laminate. In particular, when the infrared absorption layer does not function as a hard coat layer, it is preferable to further have a hard coat layer.

Examples of the curable resin used in the hard coat layer include a thermosetting resin and an ultraviolet curable resin. However, an ultraviolet curable resin is preferable because it is easy to mold, and among them, those having a pencil hardness of at least 2H. More preferred. Such curable resins can be used alone or in combination of two or more.

As such an ultraviolet curable resin, the same ultraviolet curable resin that can be used as the resin described in the above [Infrared absorbing layer] section can be used, and therefore detailed description thereof is omitted. To do.

The thickness of the hard coat layer is preferably from 0.1 μm to 50 μm, more preferably from 1 to 20 μm, from the viewpoints of improving the hard coat properties and improving the transparency of the laminated film.

The method for forming the hard coat layer is not particularly limited. For example, after preparing a coating liquid for hard coat layer containing the above components, the coating liquid is applied with a wire bar or the like, and the coating liquid is cured with heat and / or UV. And a method of forming a hard coat layer.

[Other functional layers]
The laminated film according to the present invention may have a layer (other functional layer) other than the layers described above. For example, an intermediate layer can be provided as the other layer. Here, the “intermediate layer” means a layer between the base material and the infrared absorption layer or a layer between the base material and the dielectric multilayer film.

Examples of the constituent material of the intermediate layer include polyester resin, polyvinyl alcohol resin, polyvinyl acetate resin, polyvinyl acetal resin, acrylic resin, urethane resin, and the like, and those having low compatibility and Tg of additives are preferably used.

[Production method of laminated film]
The production method of the laminated film is not particularly limited, and any method can be used as long as the infrared absorption layer having a total concentration of iron, copper and chromium contained in the infrared absorption layer of 1 to 500 ppm can be formed. Here, since the method for forming the infrared absorbing layer, the dielectric multilayer film, the adhesive layer, and the hard coat layer itself has already been described above, a detailed description of the method for manufacturing each layer (multilayer film) is omitted here.

Examples of a method for producing a laminated film include the following. (1) forming a dielectric multilayer film on one surface of the substrate (the surface opposite to the surface on which the separator and the adhesive layer are disposed), forming an infrared absorption layer on the dielectric multilayer film, Thereafter, if necessary, a method of forming a hard coat layer on the infrared absorbing layer; (2) forming a dielectric multilayer film on one surface of the substrate (surface on which the separator and the adhesive layer are disposed); Thereafter, an infrared absorbing layer is formed on the other surface of the substrate, and a hard coat layer is further formed on the infrared absorbing layer as necessary. In any of the above production methods (1) and (2), it is preferable that the step of forming the hard coat layer can be omitted when the infrared absorption layer also serves as the hard coat layer.

[Application of laminated film]
The laminated film according to 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. Moreover, it can be suitably used as a laminated film for automobiles sandwiched between glass and glass such as laminated glass for automobiles.

The effect of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. In addition, although the display of "part" or "%" may be used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

≪Production of laminated film≫
(Example 1)
-Preparation of infrared absorbing layer coating solution 1-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 1. The solid content was 30% by mass.

Methyl ethyl ketone 438 parts by weight Dianal BR-85 (acrylic resin: manufactured by Mitsubishi Rayon Co., Ltd.) 200 parts by weight Acryt 8UA-239 (urethane-modified acrylic polymer: manufactured by Taisei Fine Chemical Co., Ltd.) 300 parts by weight KCF-22 (carbon black: Sumitomo Metal Mining Co., Ltd.) 61 parts by mass MegaFuck F-552 (fluorine surfactant: manufactured by DIC) 0.1 parts by mass.

-Preparation of adhesive coating solution 1-
The constituent materials described below were sequentially added to prepare an adhesive coating solution 1.

Ethyl acetate 530 parts by weight Coponil N-2147 (acrylic pressure-sensitive adhesive: manufactured by Nippon Synthetic Chemical Industry) 433 parts by weight Tinuvin 928 (benzotriazole-based UV absorber: manufactured by BASF) 10 parts by weight Coronate L-55E (crosslinking agent) : Nippon Polyurethane Industry Co., Ltd.) 22 parts by mass.

-Production of laminated film 1-
On the surface of one easy-adhesion layer of a polyethylene terephthalate (PET) film (with double-sided easy-adhesion layer) made of a polyester resin and having a thickness of 50 μm, the infrared-absorbing coating solution 1 prepared above is liquid for 2 hours using a stainless steel pipe. It was circulated, applied with a gravure coater, and dried at 100 ° C. for 2 minutes to obtain a layer with a dry weight of 3 g / m ² (thickness: 10 μm). Then, the obtained laminated body was wound up in a roll shape so that the coated and dried layer was inside.

Next, the pressure-sensitive adhesive coating solution 1 was applied to a release surface of a separator film (NS-23MA: manufactured by Nakamoto Packs Co., Ltd.) made of polyester resin using a die coater and dried at 90 ° C. for 1 minute. I let you. Then, the said separator film provided with the adhesion layer was laminated | stacked on the surface by which the infrared rays absorption layer is not formed of the laminated body wound up in roll shape, and the laminated film 1 was produced. The thickness of the adhesive layer was 15 μm.

(Example 2)
-Production of laminated film 2-
In the above Example 1 (preparation of laminated film 1), the laminated film was made in the same manner as in Example 1 except that the solution was circulated for 6 hours using a stainless steel pipe before applying the infrared absorbing layer coating liquid 1. 2 was produced.

(Comparative Example 1)
-Production of comparative laminated film 1-
In Example 1 (preparation of laminated film 1), comparative lamination was carried out in the same manner as in Example 1 except that the solution was circulated for 18 hours using a stainless steel pipe before applying the infrared absorbing layer coating liquid 1. Film 1 was produced.

(Comparative Example 2)
-Production of comparative laminated film 2-
In Example 1 (preparation of laminated film 1), the same operation as Example 1 was performed, except that an operation of removing iron, copper and chromium by ultrafiltration was performed before applying the infrared absorbing layer coating solution 1. Thus, a comparative laminated film 2 was produced.

(Example 3)
-Preparation of infrared absorbing layer coating solution 2-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 2. The solid content was 15% by mass.

Water 62 parts by mass Isopropyl alcohol 100 parts by mass Esreck KW-1 (butyral resin: manufactured by Sekisui Chemical Co., Ltd.) 734 parts by mass Denatron P-502S (polythiophene conductive polymer, solid content: 3.0% by mass: manufactured by Nagase ChemteX) 61 parts by mass Megafac F-477 (fluorine surfactant: manufactured by DIC) 2 parts by mass.

-Production of laminated film 3-
In Example 1 (production of the laminated film 1), the infrared absorbing layer coating solution 1 is changed to the infrared absorbing layer coating solution 2 prepared as described above, and before the infrared absorbing layer coating solution 2 is applied, it is made of stainless steel. A laminated film 3 was produced in the same manner as in Example 1 except that the liquid was circulated for 6 hours using piping.

(Comparative Example 3)
-Preparation of infrared absorbing layer coating solution 3-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 3. The solid content was 30% by mass.

Methyl ethyl ketone 490 parts by weight Dianal BR-85 (acrylic resin: manufactured by Mitsubishi Rayon Co., Ltd.) 195 parts by weight Acryt 8UA-239 (urethane-modified acrylic polymer: manufactured by Taisei Fine Chemical Co., Ltd.) 300 parts by weight YKR-2200 (copper phthalocyanine: manufactured by Yamamoto Kasei Co., Ltd.) ) 15 parts by mass Megafac F-552 (fluorine surfactant: manufactured by DIC) 0.1 parts by mass.

-Production of comparative laminated film 3-
In Example 1 (preparation of laminated film 1), the infrared absorbing layer coating solution 1 is changed to the infrared absorbing layer coating solution 3 prepared as described above, and before the infrared absorbing layer coating solution 3 is applied, it is made of stainless steel. A comparative laminated film 3 was produced in the same manner as in Example 1 except that the liquid was circulated for 6 hours using piping.

Example 4
-Preparation of infrared absorbing layer coating solution 4-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 4. The solid content was 30% by mass.

Methyl ethyl ketone 237 parts by mass Dianal BR-85 (acrylic resin: manufactured by Mitsubishi Rayon Co., Ltd.) 66 parts by mass Acryt 8UA-239 (urethane-modified acrylic polymer: manufactured by Taisei Fine Chemical Co., Ltd.) 200 parts by mass SR35M (MITO dispersion of ATO particles, solid content 35.3 mass%, particle concentration 35 mass%, average particle size 80 nm, manufactured by Advanced Nano Products) 497 mass parts Megafac F-552 (fluorine surfactant: manufactured by DIC Corporation) 0.1 mass parts.

-Production of laminated film 4-
In Example 1 above, the infrared absorbing layer coating solution 1 was changed to the infrared absorbing layer coating solution 4 prepared as described above, and the solution was applied for 6 hours using a stainless steel pipe before applying the infrared absorbing layer coating solution 4. A laminated film 4 was produced in the same manner as in Example 1 (production of the laminated film 1) except that it was circulated.

(Comparative Example 4)
-Production of comparative laminated film 4-
In Example 4 (preparation of laminated film 4), comparative lamination was performed in the same manner as in Example 4 except that liquid circulation was performed for 18 hours using a stainless steel pipe before applying the infrared absorbing layer coating liquid 4. Film 4 was produced.

(Example 5)
-Preparation of UV curable resin layer coating solution-
The constituent materials described below were sequentially added to prepare a UV curable resin layer coating solution.

Aronix M-220 (Tripropylene glycol diacrylate: manufactured by Toagosei Co., Ltd.) 600 parts by mass Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 1229 parts by mass UF-8001G (oligourethane acrylate (molecular weight ~ 4500): manufactured by Kyoeisha Chemical Co., Ltd.) 150 parts by mass Purple light UV-7600B (urethane acrylate UV curable resin: manufactured by Nippon Synthetic Chemical Co., Ltd.) 300 parts by mass Irgacure 184 (photopolymerization initiator: manufactured by BASF) 120 parts by mass F-552 (fluorine surfactant: manufactured by DIC Corporation) 0.9 parts by mass.

-Production of laminated film 5-
On the infrared absorption layer of the laminated film 4 produced in Example 4, the UV curable resin layer coating solution (hard coating layer coating solution) prepared as described above was applied. Next, using an ultraviolet lamp, the illuminance of the irradiated part is 100 mW / cm ² , the irradiation amount is 0.5 J / cm ² , the coating layer is cured, and the hard coat layer (HC layer) is formed so that the dry film thickness is 4 μm. The laminated film 5 was produced.

(Example 6)
-Production of laminated film 6-
In Example 4 (production of the laminated film 4), before applying the infrared absorbing layer coating liquid 4, the liquid was circulated for 18 hours using a stainless steel pipe whose inner surface was processed with Teflon (registered trademark). A laminated film 6 was produced in the same manner as in Example 4.

(Example 7)
-Preparation of Infrared Absorbing Layer Coating Solution 5-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 5. The solid content was 44% by mass.

Methyl isobutyl ketone 86 parts by weight Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 177 parts by weight SR35M (MITO dispersion of ATO particles, solid content 35.3% by weight, particle concentration 35% by weight, Average particle size 80 nm, manufactured by Advanced Nano Products) 729 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF) 7.4 parts by mass MegaFuck F-552 (fluorinated surfactant: manufactured by DIC) 0.1 Parts by mass.

-Production of laminated film 7-
On the surface of one easy-adhesion layer of a 50 μm thick polyethylene terephthalate (PET) film (with double-sided easy-adhesion layer) made of polyester resin, the inner surface of the infrared absorbing layer coating solution 5 prepared above is processed with Teflon (registered trademark). The solution was circulated for 18 hours using a stainless steel pipe, coated with a gravure coater, and dried at 100 ° C. for 2 minutes. Next, an infrared ray absorbing layer (also serving as an HC layer) having a dry film thickness of 4 μm is cured by using an ultraviolet lamp to cure the coating layer with an illuminance of the irradiated portion of 100 mW / cm ² and an irradiation amount of 0.5 J / cm ^2. Formed. Then, the obtained laminated body was wound up in a roll shape so that the coated and dried layer was inside.

Next, the pressure-sensitive adhesive coating solution 1 was applied to a release surface of a separator film (NS-23MA: manufactured by Nakamoto Packs Co., Ltd.) made of polyester resin using a die coater and dried at 90 ° C. for 1 minute. I let you. Then, the said separate film provided with the adhesion layer was laminated on the surface by which the infrared rays absorption layer is not formed of the laminated body wound up by roll shape, and the laminated film 7 was produced. The thickness of the adhesive layer was 15 μm.

(Example 8)
-Preparation of Infrared Absorbing Layer Coating Solution 6-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 6. The solid content was 40% by mass.

Methyl isobutyl ketone 204 parts by mass Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 130 parts by mass Celnax CX-Z400K (ZnSb ₂ O ₆ fine particles (AZO) dispersion, solid content 40% by mass) , Particle concentration 40% by mass, average particle size 100 nm: manufactured by Nissan Chemical Industries, Ltd.) 660 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF Corp.) 5.4 parts by mass Megafac F-552 (fluorine-based surfactant: DIC Corporation) 0.1 parts by mass.

-Production of laminated film 8-
In Example 7 (production of the laminated film 7), the laminated film 8 was prepared in the same manner as in Example 7 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 6 prepared as described above. Produced.

Example 9
-Preparation of infrared absorbing layer coating solution 7-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 7. The solid content was 35% by mass.

Methyl isobutyl ketone 78 parts by weight Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 101 parts by weight ITO dispersion (solid content 30% by weight, particle concentration 17% by weight, average particle diameter 80 nm: Mitsubishi Materials) 817 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF) 4.2 parts by mass MegaFuck F-552 (fluorine-based surfactant: manufactured by DIC) 0.1 part by mass

-Production of laminated film 9-
In Example 7 (production of the laminated film 7), the laminated film 9 was prepared in the same manner as in Example 7 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 7 prepared as described above. Produced.

(Example 10)
-Preparation of infrared absorbing layer coating solution 8-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 8. The solid content was 30% by mass.

Methyl isobutyl ketone 542 parts by mass Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 259 parts by mass KHF-7AH (LaB ₆ , solid content 16% by mass, particle concentration 3.2% by mass, toluene dispersion Body, average particle size 50 nm: manufactured by Sumitomo Metal Mining Co., Ltd.) 187 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF) 10 parts by mass MegaFuck F-552 (fluorinated surfactant: manufactured by DIC) 0.1 Parts by mass.

-Production of laminated film 10-
In Example 7 (production of the laminated film 7), the laminated film 10 was prepared in the same manner as in Example 7 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 8 prepared as described above. Produced.

(Example 11)
-Preparation of Infrared Absorbing Layer Coating Liquid 9-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 9. The solid content was 30% by mass.

Methyl isobutyl ketone 451 parts by mass Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 193 parts by mass YMF-02A (cesium-doped tungsten oxide (Cs _0.33 WO ₃ ), solid content 28.7 Mass%, particle concentration 18.5% by mass, average particle diameter 15 nm, refractive index 1.66: manufactured by Sumitomo Metal Mining Co., Ltd.) 347 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF) 7 parts by mass MegaFuck F- 552 (fluorine-based surfactant: manufactured by DIC) 0.1 parts by mass.

-Production of laminated film 11-
In Example 7 (production of laminated film 7), the laminated film 11 was prepared in the same manner as in Example 7 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 9 prepared as described above. Produced.

(Comparative Example 5)
-Production of comparative laminated film 5-
In Example 8 (production of the laminated film 8), before applying the infrared absorbing layer coating liquid 6, the liquid was circulated for 18 hours using a stainless steel pipe (the inner surface of which was not processed with Teflon (registered trademark)). A comparative laminated film 5 was produced in the same manner as in Example 8 except that.

Example 12
-Preparation of coating solution L1 for low refractive index layer-
The constituent materials described below were sequentially added and stirred at 45 ° C. Finally, it was finished to 1000 parts by mass with pure water to prepare a coating solution L1 for a low refractive index layer.

Water 85 parts by weight Colloidal silica (10% by weight, average particle size 4-6 nm, manufactured by Nissan Chemical Industries, Ltd .; Snowtex OXS) 430 parts by weight Boric acid aqueous solution (3% by weight) 150 parts by weight Polyvinyl alcohol (4% by weight, JP- 45, manufactured by Nihon Vinegar & Poval, polymerization degree 4500, saponification degree 88 mol%) 300 parts by mass Softazoline LSB-R (5% by mass, lauramidopropylhydroxysultain (long-chain alkyl group-containing amphoteric surfactant), Kawaken 3 parts by mass)

The refractive index of the layer formed with the coating liquid L1 for the low refractive index layer was 1.48. In addition, the measuring method of a refractive index is as follows (hereinafter the same).

<Measurement of single-film refractive index of each layer>
In order to measure the refractive index, a sample in which the low refractive index layer coating liquid L1 was applied as a single layer on a base material was prepared, and after cutting this sample into 10 cm × 10 cm, the refractive index was determined according to the following method. . Using Hitachi spectrophotometer U-4100 (solid sample measurement system), the surface opposite to the measurement surface (back surface) of each sample is roughened and then light absorption is performed with a black spray. Then, reflection of light on the back surface was prevented, and the reflectance in the visible light region (400 nm to 700 nm) was measured under the condition of regular reflection at 5 degrees, and the refractive index was obtained from the result.

-Preparation of coating liquid H1 for high refractive index layer-
According to the following procedure, the coating liquid H1 for high refractive index layers was prepared.

<Preparation of aqueous dispersion of titanium oxide sol>
First, a titanium oxide sol dispersion containing rutile-type titanium oxide was prepared as follows.

30 L of an aqueous sodium hydroxide solution (concentration 10 mol / L) was added with stirring to 10 L (liter) of an aqueous suspension (TiO ₂ concentration 100 g / L) in which titanium dioxide hydrate was suspended in water. The mixture was heated to 0 ° C. and aged for 5 hours, then neutralized with hydrochloric acid, filtered and washed with water. In the above reaction (treatment), titanium dioxide hydrate was obtained by thermal hydrolysis of an aqueous titanium sulfate solution according to a known method.

The base-treated titanium compound was suspended in pure water to a TiO ₂ concentration of 20 g / L, and 0.4 mol% of citric acid was added to the amount of TiO ₂ with stirring to raise the temperature. When the liquid temperature reached 95 ° C., concentrated hydrochloric acid was added to a hydrochloric acid concentration of 30 g / L, and the mixture was stirred for 3 hours while maintaining the liquid temperature.

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

1 kg of pure water was added to 1 kg of 20.0 mass% titanium oxide sol aqueous dispersion containing rutile-type titanium oxide particles having a volume average particle size of 35 nm to obtain 10.0 mass% titanium oxide sol aqueous dispersion.

<Preparation of aqueous silicic acid solution>
An aqueous silicic acid solution having a SiO ₂ concentration of 2.0 mass% was prepared.

<Preparation of silica-modified titanium oxide particles>
2 kg of pure water was added to 0.5 kg of the 10.0 mass% titanium oxide sol aqueous dispersion (including rutile type titanium oxide particles), and then heated to 90 ° C. Thereafter, 1.3 kg of a 2.0 mass% aqueous silicic acid solution was gradually added, and then the obtained dispersion was subjected to heat treatment at 175 ° C. for 18 hours in an autoclave and further concentrated to obtain a rutile structure. A sol-water dispersion of 20% by mass of silica-modified titanium oxide particles having a coating layer of SiO ₂ and having a titanium oxide layer was obtained.
When the particle size of the obtained silica-modified titanium oxide particle sol aqueous dispersion was measured with Zetasizer Nano manufactured by Malvern, the volume average particle size was 35 nm and the monodispersity was 16%.

<Preparation of coating liquid H1 for high refractive index layer>
Using the sol water dispersion of silica-modified titanium oxide particles obtained by the above procedure, the following constituent materials were sequentially added and stirred at 45 ° C. Finishing with pure water to 1000 parts by mass, a coating solution H1 for a high refractive index layer was prepared.

Sol dispersion of silica-modified titanium oxide particles (20.0% by mass) 320 parts by mass Citric acid aqueous solution (1.92% by mass) 120 parts by mass Polyvinyl alcohol (10% by mass, PVA103, polymerization degree 300, saponification degree 99 mol%) 20 parts by mass Boric acid aqueous solution (3% by mass) 100 parts by mass Polyvinyl alcohol (4% by mass, manufactured by Kuraray Co., Ltd., PVA124, polymerization degree 2400, saponification degree 88 mol%) 350 parts by mass Softazoline LSB-R (5 masses) %, Lauramidopropylhydroxysultain (long-chain alkyl group-containing amphoteric surfactant), manufactured by Kawaken Fine Chemical Co., Ltd. 1 part by mass.

The refractive index of the layer formed with the high refractive index layer coating solution H1 was 1.82.

-Formation of dielectric multilayer film-
Using a slide hopper coating apparatus capable of 10-layer multilayer coating, the thickness obtained by heating the low refractive index layer coating liquid L1 and the high refractive index layer coating liquid H1 obtained above to 45 ° C. while maintaining the temperature at 45 ° C. A polyethylene terephthalate (PET) film having a thickness of 50 μm (Toyobo Co., Ltd. A4300: double-sided easy-adhesive layer, length 200 m × width 210 mm), the lowermost layer and the uppermost layer are low refractive index layers, and the others are alternately dried. A total of nine layers were simultaneously applied so that the low refractive index layer had a thickness of 150 nm and the high refractive index layer had a thickness of 130 nm. In addition, the measurement (confirmation) of the film thickness is performed by cutting the laminated film (laminated film sample) and using the XPS surface analyzer to cut the cut surface with the abundance of the high refractive index material (TiO ₂ ) and the low refractive index material (SiO ₂ ). It was confirmed that the film thickness of each of the above layers was secured by measuring.

Immediately after application, it was set by blowing cold air of 5 ° C. 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 form a dielectric multilayer film consisting of 10 layers.

-Production of laminated film 12-
In the base material having the dielectric multilayer film produced as described above, the infrared absorbing layer coating solution 5 prepared above is applied to the surface on the side where the dielectric multilayer film is not formed (the easy adhesion layer), and the inner surface is coated with Teflon ( (Registered trademark) Liquid was circulated for 18 hours using a processed stainless steel pipe and applied by a gravure coater. Subsequent operations were performed in the same manner as in Example 7 (production of laminated film 7), and laminated film 12 was produced.

(Example 13)
-Production of laminated film 13-
A laminated film 13 was produced in the same manner as in Example 12 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 9 in Example 12 (production of the laminated film 12).

(Example 14)
-Preparation of infrared absorbing layer coating solution 10-
The constituent materials described below were sequentially added to prepare an infrared absorption layer coating solution 10. The solid content was 40% by mass.

Methyl isobutyl ketone 219 parts by mass Beam set 577 (urethane acrylate UV curable resin: manufactured by Arakawa Chemical Industries) 209 parts by mass YMF-02A (cesium-doped tungsten oxide (Cs _0.33 WO ₃ ), solid content 28.7 Mass%, particle concentration 18.5 mass%, average particle diameter 15 nm, refractive index 1.66: manufactured by Sumitomo Metal Mining Co., Ltd. 232 parts by mass SR35M (MITO dispersion of ATO particles, solid content 35.3% by mass, particle concentration 35% by mass, average particle size 80 nm, manufactured by Advanced Nano Products) 331 parts by mass Irgacure 819 (photopolymerization initiator: manufactured by BASF) 9 parts by mass MegaFuck F-552 (fluorinated surfactant: manufactured by DIC) 0 .1 part by mass.

-Production of laminated film 14-
In Example 12 (production of the laminated film 12), the laminated film 14 was prepared in the same manner as in Example 12 except that the infrared absorbing layer coating solution 5 was changed to the infrared absorbing layer coating solution 10 prepared as described above. Produced.

(Comparative Example 6)
-Production of comparative laminated film 6-
In the above Example 12 (production of the laminated film 12), before applying the infrared absorbing layer coating liquid 5, a comparative lamination was performed in the same manner as in Example 12 except that the liquid circulation was performed for 18 hours using a stainless steel pipe. Film 6 was produced.

≪Evaluation≫
[Measurement of metal concentration]
In the above examples and comparative examples, 10 mL of the infrared absorbing layer coating solution immediately before coating was collected, dried, and coated with ICP-AES (inductively coupled plasma emission spectrometer, manufactured by Shimadzu Corporation, ICPS-7500). The contents of iron, copper and chromium in the film were measured, and the total of these was calculated to determine the total concentration. The obtained results are shown as an item of “Concentration of specific metal in infrared absorbing layer” in Tables 1-1 and 1-2. In addition, the said value is the sum total density | concentration of iron, copper, and chromium with respect to the mass of the total solid of an infrared rays absorption layer.

Furthermore, regarding the contents of iron, copper, and chromium, the results of calculating the concentration with respect to the surfactant contained in the infrared absorption layer and the concentration with respect to the infrared absorber contained in the infrared absorption layer are also shown. In the above, the measured value of the content of iron, copper and chromium in the sample obtained by collecting and drying the infrared absorbing layer coating solution immediately before coating is the infrared absorbing layer of the laminated film produced using the coating solution. It was confirmed that the value was the same as the middle value.

[Evaluation of durability]
The laminated films produced in the above examples and comparative examples were each attached to 3 mm thick float glass. Next, using a sunshine weather meter using a carbon arc lamp as an accelerated weathering tester so that light enters from the glass surface, an illuminance of 250 W / cm in an environment of a temperature of 40 ° C. and a humidity of 50% RH. ² for 120 minutes. At this time, water injection was repeatedly performed for 18 minutes. Then, after performing light irradiation for 2000 hours, the following method observed the presence or absence of a crack, the measurement of haze, and color difference evaluation.

(Observation of cracks)
A laminated film sample 15 cm × 5 cm (75 cm ² ) was visually observed, the number of cracks was counted, and evaluated based on the average value of 10 laminated film samples according to the following criteria. The results are shown in Table 1-2.

◎: 0 ◯: 1 to 5 △: 6 to 10 △: 11 to 25 ×: 26 or more In addition, ◎, ○, ○ △, and △ can be used without any problem in practice.

(Measure haze)
For laminated film sample 15cm × 5cm (75cm ^2), using a haze meter (NDH7000 type manufactured by Nippon Denshoku Industries Co., Ltd.) and the haze measured at 5 points, the average value obtained was haze measurements. The results are shown in Table 1-2. In addition, as a haze value of a heat-shielding film, it is preferable in it being 1.5% or less.

(Color difference evaluation)
The color difference (ΔE) of the laminated film sample was evaluated before and after the light irradiation under the above conditions. For the color difference evaluation, a spectrocolorimeter CM-3700d (manufactured by Konica Minolta Co., Ltd.) was used, ΔE was obtained from the CIE Lab value, and evaluated according to the following criteria. The results are shown in Table 1-2.

A: 0.0 ≦ ΔE ≦ 1.0
○: 1.0 <ΔE ≦ 2.0
Δ: 2.0 <ΔE ≦ 3.0
×: 3.0 <ΔE
Note that ◎, ○, and Δ are not markedly discolored and can be used without any practical problems.

According to Table 1-1 and Table 1-2, when the total concentration of iron, copper and chromium in the infrared absorbing layer is in the range of 1 to 500 ppm, it is difficult to discolor, less cracking occurs, and haze It was shown that a laminated film with reduced can be obtained.

Here, in particular, in Examples 5 and 6, when ATO is used as the infrared absorber and the total concentration of the specific metal is in the range of 100 to 300 ppm, the crack suppression and haze reduction effects are enhanced. Became clear.

It has also been clarified that when the laminated film further includes a dielectric multilayer film, discoloration and cracking are suppressed and the haze reduction effect is further improved. This is considered to be due to the fact that, in the durability evaluation, light incident from the side of the dielectric multilayer film provides a shielding effect in the dielectric multilayer film, and thus light incident on the infrared absorption layer is reduced. .

Furthermore, this application is based on Japanese Patent Application No. 2014-146136 filed on July 16, 2014, the disclosure of which is incorporated by reference in its entirety.

Claims (6)

A substrate;
An infrared absorbing layer containing an infrared absorber and a resin, disposed on one surface of the substrate;
A laminated film in which the total concentration of iron, copper and chromium contained in the infrared absorbing layer is 1 to 500 ppm. The laminated film according to claim 1, wherein the total concentration of the iron, copper and chromium with respect to the infrared absorbent is 100 to 26000 ppm in the infrared absorbent layer. The infrared absorption layer further includes a surfactant, and the total concentration of the iron, copper, and chromium with respect to the surfactant in the infrared absorption layer is more than 0.3% by mass and less than 160% by mass. Item 3. The laminated film according to Item 1 or 2. The infrared absorber is antimony-doped tin oxide, indium-doped tin oxide, cesium-doped tungsten oxide, lanthanum hexaboride, antimony-doped zinc oxide, indium-doped zinc oxide, conductive polymer, conductive carbon material The laminated film according to any one of claims 1 to 3, which is at least one selected from the group consisting of: Further comprising a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately laminated,
The laminated film according to any one of claims 1 to 4, wherein the low refractive index layer or the high refractive index layer contains metal oxide particles. A method for producing a laminated film having an infrared absorbing layer containing an infrared absorbent and a resin on one surface of a substrate,
A method for producing a laminated film, comprising a step of preparing a coating solution so that a total concentration of iron, copper and chromium contained in the infrared absorbing layer is 1 to 500 ppm.