Resin composition for forming infrared absorbing layer, infrared absorbing filter, and method for producing resin composition for forming infrared absorbing layer

Abstract

The present invention provides: a resin composition for forming an infrared absorbing layer; an infrared absorbing filter; and the like.　The present invention specifically provides a resin composition for forming an infrared absorbing layer, the resin composition containing, at a specific ratio, (A) nanoparticles which are derived from a transparent conductive oxide and serve as an infrared absorbent, (B) a resin component which serves as a dispersion medium for the infrared absorbent, (C) a solvent for the resin component, and (D) a dispersion assistant. The present invention also specifically provides: a method for producing the resin composition for forming an infrared absorbing layer; and an infrared absorbing filter that has an infrared absorbing layer, which is derived from the resin composition for forming an infrared absorbing layer, on a base material, and that has a maximum absorption wavelength within the range of 800-15,000 nm and a light transmittance of 65% or more in the visible light wavelength region of 380-780 nm.

Description

Resin composition for forming infrared absorbing layer, infrared absorbing filter, and method for producing resin composition for forming infrared absorbing layer

[0001] The present invention relates to a resin composition for forming an infrared absorbing layer, an infrared absorbing filter, and a method for producing a resin composition for forming an infrared absorbing layer.

[0002] BACKGROUND ART In the past, resin compositions for forming various infrared absorbing layers and paints using the same have been proposed for the purpose of imparting infrared heat shielding properties or the like.

[0003] For example, nano-tin-containing metal oxide particles and dispersions thereof have been proposed in relation to composite materials for glass that are highly transparent, low radiative, and energy-saving. For example, Patent Document 1 discloses nano-tin-containing metal oxide particles that contain tin and one metal element other than tin, have a particle size distribution defined by a dispersity index of less than 5 and a steepness ratio of less than 2, and have an average primary particle size of 2 to 50 nm.

[0004] Also proposed is a solvent-free transparent conductive paint that forms a transparent conductive coating for antistatic treatment on the surface of plastic products and is used for flooring and wall materials in clean rooms, packaging materials for semiconductors, display components for meters, etc. For example, Patent Document 2 discloses a transparent conductive paint characterized by antimony-doped tin oxide fine particles with a particle size of 10 to 100 angstroms dispersed in a binder resin without containing a solvent.

[0005] Special Publication No. 2015-511575 Publication JP-A No. 8-27405

[0006] However, the nano-tin-containing metal oxide particles disclosed in Patent Document 1 are unclear in terms of the configuration and technical significance of the invention, and there is room for further improvement in terms of infrared absorption.

[0007] Furthermore, in the transparent conductive paint disclosed in Patent Document 2, antimony-doped tin oxide microparticles of a predetermined particle size dispersed in a binder resin tend to aggregate strongly, resulting in reduced dispersion stability or poor transparency, etc.

[0008] Therefore, an object of the present invention is to provide a resin composition for forming an infrared absorbing layer, which contains an infrared absorbent that is excellent in infrared absorbency, transparency, dispersibility, durability, and printing characteristics; an infrared absorbing filter using the same; and a method for producing a resin composition for forming an infrared absorbing layer.

[0009] In view of the above circumstances, the present inventors have made extensive efforts and have found that by using nanoparticles derived from transparent conductive oxides as an infrared absorber and by using a predetermined dispersing aid or the like, a resin composition for forming an infrared absorbing layer that is excellent in dispersion stability and transparency, as well as durability and printing properties, can be obtained, and have thus completed the present invention.

[0010] That is, the present invention provides a resin composition for forming an infrared-absorbing layer, comprising: (A) component (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbent; (B) component (B) resin component as a dispersion medium for the infrared absorbent; (C) component (C) solvent for the resin component; and (D) component (D) carboxyl group-containing compound as a dispersion aid for the infrared absorbent. Here, the blending amount of component (B) is set to a value within a range of 5,000 to 15,000 parts by weight, the blending amount of component (C) is set to a value within a range of 22,000 to 80,000 parts by weight, and the blending amount of component (D) is set to a value within a range of 20 to 2,000 parts by weight, relative to 100 parts by weight of component (A). This resin composition for forming an infrared-absorbing layer can solve the above-mentioned problems.

[0011] Furthermore, in constructing the infrared-absorbing layer-forming resin composition of the present invention, it is preferable that component (A) is ITO nanoparticles having at least one polar group selected from amino groups, hydroxyl groups, epoxy groups, and carboxyl groups at least on the surface and an average particle size within the range of 0.1 to 100 nm. By configuring in this manner, when such ITO nanoparticles are dispersed in various solvents, the transparency can be more easily maintained, and the surface state can be further modified by reacting various dispersing aids with the polar groups on the surface of nanoparticles derived from transparent conductive oxides, etc.

[0012] In addition, when forming the resin composition for forming an infrared absorbing layer of the present invention, the component (B) is 50 mJ / m ２It is preferable that the thermoplastic resin has the following surface free energy: By configuring in this way, it is possible to provide a resin composition for forming an infrared absorbing layer that is even more excellent in transparency, dispersibility, printing properties, etc., even when mixed and dispersed in a thermoplastic resin having a predetermined surface free energy, for example.

[0013] In addition, when forming the infrared-absorbing layer-forming resin composition of the present invention, it is preferable that the component (C) contains at least one ketone-based solvent. This configuration makes it easier for various thermoplastic resins to dissolve in the specified component (C). Therefore, when specified ITO nanoparticles are dispersed in the resin solution, a resin composition for forming an infrared-absorbing layer having superior transparency, dispersibility, printing properties, and the like can be provided.

[0014] Furthermore, in forming the infrared-absorbing layer-forming resin composition of the present invention, it is preferable that the component (D) contains at least one of an aromatic carboxylic acid, an alkyl carboxylate (the alkyl group has 1 to 28 carbon atoms), and an alkyl carboxylate ester (the alkyl group has 1 to 28 carbon atoms). By configuring in this manner, even in cases where, for example, nanoparticles derived from a transparent conductive oxide are blended as a predetermined infrared absorbent into a thermoplastic resin having low surface free energy, such as a non-polar resin, the predetermined infrared absorbent is uniformly mixed and dispersed via the predetermined component (D), and thus it is possible to provide a resin composition for forming an infrared-absorbing layer that is even more excellent in transparency, dispersibility, printing properties, and the like.

[0015] Another aspect of the present invention is an infrared absorbing filter comprising, on a substrate, an infrared absorbing layer derived from a resin composition for forming an infrared absorbing layer, the resin composition including (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbent, (B) a resin component as a dispersion medium for the infrared absorbent, (C) a solvent for the resin component, and (D) a carboxyl group-containing compound as a dispersion aid for the infrared absorbent, wherein the infrared absorbing layer has a maximum absorption wavelength in the range of 800 to 15,000 nm and a light transmittance of 65% or more in the visible light region having a wavelength of 380 to 780 nm.

[0016] By configuring an infrared absorbing filter in this manner, nanoparticles derived from a predetermined transparent conductive oxide are used, and a dispersion aid or the like for a predetermined infrared absorber is also used, whereby an infrared absorbing resin composition excellent in transparency, dispersibility, printing properties, and the like can be obtained, and an infrared absorbing filter can be easily obtained.

[0017] In the resin composition for forming an infrared-absorbing layer, it is preferable that the blending amount of the (B) component is set to a value within a range of 5,000 to 15,000 parts by weight, the blending amount of the (C) component is set to a value within a range of 22,000 to 80,000 parts by weight, and the blending amount of the (D) component is set to a value within a range of 20 to 2,000 parts by weight, relative to 100 parts by weight of the (A) component.

[0018] In addition, it is preferable that the infrared absorbing resin composition layer is disposed on the substrate so as to have a predetermined pattern.

[0019] Yet another aspect of the present invention is a method for producing a resin composition for forming an infrared absorbing layer, comprising: (A) nanoparticles derived from a transparent conductive oxide as an infrared absorber; (B) a resin component as a dispersion medium for the infrared absorber; (C) a solvent for the resin component; and (D) a carboxyl group-containing compound as a dispersion aid for the infrared absorber, the method comprising the following steps (1) to (3): (1) a step of placing at least one transparent conductive oxide precursor and a polar solvent having a boiling point of 250°C or higher into a container; (2) A step of increasing the temperature inside the container to 250 to 350°C, oxidatively decomposing the precursor of the transparent conductive oxide, and producing nanoparticles derived from the transparent conductive oxide as an infrared absorber, which have polar groups at least on their surfaces. (3) A step of taking out the nanoparticles derived from the transparent conductive oxide, mixing and dispersing them in a predetermined ratio of 5,000 to 15,000 parts by weight of the component (B), 22,000 to 80,000 parts by weight of the component (C), and 20 to 2,000 parts by weight of the component (D) relative to 100 parts by weight of the component (A), to obtain a resin composition for forming an infrared absorbing layer.

[0020] By carrying out the method for producing a resin composition for forming an infrared absorbing layer in this manner, it is possible to efficiently produce a resin composition for forming an infrared absorbing layer that is excellent in infrared absorbency, transparency, dispersibility, printing properties, etc. Note that it is also possible to mix and disperse nanoparticles derived from a predetermined transparent conductive oxide in a polar resin as well as a non-polar resin, etc.

[0021] In the present invention, by using nanoparticles derived from a predetermined transparent conductive oxide as the infrared absorbent and by using a predetermined dispersion aid for the infrared absorbent, etc., it is possible to provide a resin composition for forming an infrared absorbing layer that is excellent in infrared absorbency, transparency, dispersibility, durability, printing properties, etc. Also provided are an infrared absorbing filter using this resin composition for forming an infrared absorbing layer, and a method for producing the resin composition for forming an infrared absorbing layer.

[0022] Figures 1(a) to 1(c) are conceptual diagrams illustrating an infrared absorbing layer derived from the resin composition for forming an infrared absorbing layer of the present invention. Figures 2(a) to 2(c) are plan views (photographs) illustrating the surface of an infrared absorbing layer derived from the resin composition for forming an infrared absorbing layer of the present invention. Figure 3(a) is a diagram illustrating the relationship between the tin (Sn) doping amount (wt%) in component (A) and the maximum absorption wavelength (nm) in the infrared region (for nanoparticles with an average particle size of 14 to 16 nm). Figure 3(b) is a diagram illustrating the relationship between the average particle size (nm) of component (A) and the maximum absorption wavelength (nm) in the infrared region (for nanoparticles with a doping amount of 0.01%). Figure 3(c) is a particle size distribution chart illustrating the particle size distribution of the infrared absorbent. Figures 4(a) to 4(d) are example light transmittance charts for infrared absorbing layers derived from different types of infrared absorbents. FIGS. 5(a) to 5(c) are diagrams provided to explain the relationship between the components (B) to (D) and the evaluation (relative value) of dispersion stability, respectively. FIGS. 6(a) to 6(e) are diagrams provided to explain configuration examples of infrared absorbing filters. FIG. 7 is a flow chart for explaining an example of a method for manufacturing an infrared absorbing filter. FIGS. 8(a) to 8(e) are diagrams provided to explain an example of a method for manufacturing a patterned infrared absorbing filter. FIG. 9 is a diagram provided to show the relationship between the blending amount of the infrared absorber (component (A)), the absorption intensity at the absorption maximum wavelength, and the transmittance in the visible light region. FIG. 10 is a diagram provided to show the relationship between the type (types 1 to 4) of the infrared absorber (component (A)) and the absorption maximum wavelength (nm) in the infrared region.

[0023] [First Embodiment] The first embodiment of the present invention is a resin composition for forming an infrared-absorbing layer, comprising: (A) component (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbent; (B) component (B) resin component as a dispersion medium for the infrared absorbent; (C) component (C) solvent for the resin component; and (D) component (D) carboxyl group-containing compound as a dispersion aid for the infrared absorbent. Here, the amount of component (B) is set to a value within a range of 5,000 to 15,000 parts by weight, the amount of component (C) is set to a value within a range of 22,000 to 80,000 parts by weight, and the amount of component (D) is set to a value within a range of 20 to 2,000 parts by weight, relative to 100 parts by weight of component (A).

[0024] Hereinafter, the resin composition for forming an infrared-absorbing layer according to the first embodiment will be specifically described by dividing it into constituent elements and referring to Fig. 1 and Fig. 2. Here, Fig. 1(a) to Fig. 1(c) are conceptual diagrams provided for explaining an infrared-absorbing layer derived from the resin composition for forming an infrared-absorbing layer according to the first embodiment. Also, Fig. 2(a) to Fig. 2(c) are diagrams (photographs) provided for explaining the surface of an infrared-absorbing layer derived from the resin composition for forming an infrared-absorbing layer.

[0025] 1. Component (A) (1) Type The infrared absorber may be any type of nanoparticle derived from a transparent conductive oxide that absorbs infrared rays. For example, nanoparticles derived from a transparent conductive oxide that effectively absorb infrared rays in the wavelength region of 800 to 15,000 nm, particularly in the near-infrared region (e.g., 750 to 1,400 nm), are preferred.

[0026] Examples of such nanoparticles derived from transparent conductive oxides include nanoparticles derived from at least one transparent conductive oxide selected from titanium oxide, zinc oxide, indium oxide, tin oxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), tin-doped zinc oxide (IZO), antimony-doped zinc oxide (AZO), tin-antimony-doped indium oxide (IATO), tin-antimony-doped zinc oxide (ZATO), and zinc sulfide.

[0027] In particular, among the nanoparticles derived from these transparent conductive oxides, tin-doped indium oxide (ITO) is a more suitable transparent conductive oxide because it has excellent moisture resistance and can provide good conductivity even when mixed in a relatively small amount.

[0028] Furthermore, when the transparent conductive oxide-derived nanoparticles are nanoparticles doped with a dopant such as tin or antimony, it is preferable to set the dopant content to a value of 0.001 to 20 wt% relative to the total nanoparticle content (100 wt%). The reason for this is that if the doping content is less than 0.001 wt%, the absorption of short-wavelength infrared light and, ultimately, ultraviolet light may decrease. On the other hand, if the doping content exceeds 20 wt%, the infrared absorption may decrease, and the heat-shielding effect may decrease. Therefore, it is more preferable to set the dopant content to a value of 0.01 to 10 wt%, and even more preferably to a value of 0.1 to 3.5 wt%.

[0029] FIG. 3(a) shows the relationship between the doping amount of the dopant in the infrared absorber and the maximum absorption wavelength (nm) in the infrared region. FIG. 3(a) shows the maximum absorption wavelength versus the doping amount for resin compositions in which only the doping amount of tin (Sn) in the infrared absorber (nanoparticles with an average particle size of 14 to 16 nm) was changed in the resin composition corresponding to Example 1 described below. As is clear from FIG. 3(a), the greater the doping amount of tin in the infrared absorber, the shorter the maximum absorption wavelength (nm) of the infrared absorber in the infrared region tends to be. Therefore, by controlling the doping amount of the dopant in the infrared absorber, the maximum absorption wavelength (nm) of the infrared absorber in the infrared region can also be controlled.

[0030] Furthermore, the amount of the infrared absorbent blended is preferably 0.01 to 1 wt % relative to the total amount (100 wt %) of the resin composition for forming an infrared-absorbing layer. The reason for this is that if the blending amount is less than 0.01 wt %, the amount of infrared absorbent contained will be small, and the heat-shielding effect may be reduced. On the other hand, if the blending amount exceeds 1 wt %, it may be economically disadvantageous or the handling may be reduced. Therefore, the blending amount of the infrared absorbent is more preferably 0.05 to 0.6 wt %, and even more preferably 0.1 to 0.4 wt %.

[0031] (2) Use of Combinations It is also preferable to use a combination of two or more infrared absorbents that differ in average particle size / particle size distribution, maximum absorption wavelength, visible light transmittance, presence or absence of a predetermined polar group, etc.

[0032] For example, it is preferable to prepare a first infrared absorbent having an absorption maximum wavelength of 800 to 1,000 nm and a second infrared absorbent having an absorption maximum wavelength of more than 1,000 nm, and combine them in a weight ratio of, for example, 10 / 90 to 90 / 10. This makes it easy to exhibit infrared absorption in a wider range (for example, 800 to 1,500 nm). More specifically, a combination of ITO and CuS, a combination of AZO and ITO, a combination of GZO and Bi ２ WO ４ Combination with MoO ３－ｘ and W.O. ３－ｘ Examples of suitable combinations include, but are not limited to, the combination of "x" and "x", where "x" is any real number between 0 and 1. It is also preferable to use a combination of two types of ITO or AZO with different doping amounts.

[0033] Furthermore, a first infrared absorbent having an absorption maximum wavelength of 900 to 1,200 nm, a second infrared absorbent having an absorption maximum wavelength of more than 1,200 nm, and a third infrared absorbent having an absorption maximum wavelength of 800 nm or more but less than 900 nm and a UV absorption peak at less than 450 nm can be prepared and combined in, for example, an 80 / 10 / 10 (weight ratio). This not only enhances infrared absorption over a wide range (e.g., 800 to 1,500 nm), but also makes it easier to achieve a predetermined UV absorption. More specifically, a combination of ITO, CuS, and GZO, a combination of AZO, ITO, and CuS, a combination of GZO, Bi ２ WO ４ and FeGa ２ O ３ and MoO ３－ｘ , W.O. ３－ｘ and IZO, but are not limited thereto. It is also preferable to use a combination of three types of ITO or AZO with different doping amounts.

[0034] It is also preferable to use a mixture of two or more types of nanoparticles derived from transparent conductive oxides as an infrared absorbing agent and organic infrared absorbing agents.

[0035] Examples of such organic infrared absorbers include at least one of cyanine compounds, squarylium compounds, thiol nickel complex salt compounds, naphthalocyanine compounds, phthalocyanine compounds, triallylmethane compounds, naphthoquinone compounds, anthraquinone compounds, and further amino compounds such as N,N,N',N'-tetrakis(p-di-n-butylaminophenyl)-p-phenylenediaminium perchlorate, phenylenediaminium chlorine salt, phenylenediaminium hexafluoroantimonate, phenylenediaminium fluoroborate, phenylenediaminium fluoride salt, and phenylenediaminium perchlorate; and phosphate copper compounds obtained by reacting a copper compound with a bisthiourea compound, a phosphorus compound with a copper compound, or a phosphate ester compound with a copper compound.

[0036] Among these, thiol nickel complex salt compounds and phthalocyanine compounds are preferred. In particular, fluorine-containing phthalocyanine compounds have high visible light transmittance and excellent properties such as heat resistance, light resistance, and weather resistance, and are therefore suitable when used in combination with nanoparticles derived from transparent conductive oxides.

[0037] (3) Average Particle Size The average particle size of the nanoparticles derived from the transparent conductive oxide is preferably set to a value within the range of 0.1 to 100 nm. This is because, by limiting the average particle size in this way, when the nanoparticles derived from the transparent conductive oxide are dispersed in various solvents or resins, it becomes easier to stably maintain a transparent state while maintaining a predetermined infrared absorption property. More specifically, when the average particle size of the infrared absorber is less than 0.1 nm, it is prone to aggregation, making handling difficult and making it difficult to adjust the infrared absorptivity and visible light transmittance. On the other hand, when the average particle size of the infrared absorber exceeds 100 nm, it is prone to precipitation in solvents or resin solutions, and it may be difficult to mix and disperse the infrared absorber into a predetermined resin. Therefore, it is more preferable to set the average particle size of the infrared absorber to a value within the range of 1 to 100 nm, and it is also preferable to set the average particle size of the infrared absorber to a value within the range of 2 to 80 nm, and it is even more preferable to set the average particle size of the infrared absorber to a value within the range of 5 to 50 nm.

[0038] The average particle size of the infrared absorber is measured in accordance with JIS Z 8901:2006, and more specifically, it can be calculated as D50 in a particle size distribution chart obtained from an electron microscope photograph using an image analyzer.

[0039] FIG. 3(b) shows the relationship between the average particle size of the infrared absorbent and the maximum absorption wavelength (nm) in the infrared region. FIG. 3(b) shows the maximum absorption wavelength versus the average particle size of the infrared absorbent for resin compositions in which only the average particle size of the infrared absorbent (nanoparticles with a doping amount of 0.01%) was changed in the resin composition corresponding to Example 1 described below. As is clear from FIG. 3(b), the larger the average particle size of the infrared absorbent, the longer the maximum absorption wavelength (nm) of the infrared absorbent in the infrared region tends to be. Therefore, by controlling the average particle size of the infrared absorbent, the maximum absorption wavelength (nm) of the infrared absorbent in the infrared region can also be controlled.

[0040] (4) Particle Size Distribution Next, referring to FIG. 3(c), a particle size distribution chart showing the particle size distribution of the infrared absorber will be described. Such a particle size distribution chart can be measured in accordance with, for example, JIS Z 8825:2013 or the corresponding ISO 13320:2009, but can also be measured in accordance with a particle size analysis-laser diffraction / scattering method. From the obtained particle size distribution chart, D50 can be calculated, and this value can be defined as the average particle size in the particle size distribution.

[0041] (5) Absorption Maximum Wavelength (Maximum Absorption Wavelength) Figures 4(a) to (d) are example light transmittance charts for infrared absorbing layers derived from different types of infrared absorbents (Types 1 to 4). As shown in these charts, it is generally preferable to set the absorption maximum wavelength of the infrared absorbent (or infrared absorbing layer) to a value within the range of 800 to 15,000 nm. This is because limiting the absorption maximum wavelength in this manner makes it easier to reliably maintain a predetermined infrared absorption property while stably maintaining a transparent state, even in a solution state, etc. More specifically, if the absorption maximum wavelength of the infrared absorbent is less than 800 nm, the infrared absorption and heat-shielding effect may decrease. On the other hand, if the absorption maximum wavelength of such an infrared absorbent is greater than 15,000 nm, the absorption of short-wavelength infrared light and, ultimately, ultraviolet light may decrease.

[0042] Therefore, although it depends on the application, it is more preferable to set the absorption maximum wavelength of the infrared absorbent to a value within the range of 830 to 5,000 nm, and even more preferable to set the absorption maximum wavelength of the infrared absorbent to a value within the range of 850 to 1,500 nm. Note that the absorption intensity at the absorption maximum wavelength of the infrared absorbent can be controlled by at least the blending amount of the infrared absorbent, which is component (A), as shown in Figure 9.

[0043] (6) Visible Light Transmittance The visible light transmittance of the infrared absorber (or infrared absorbing layer) is preferably 65% ​​or more in the visible light region of wavelengths 380 to 780 nm. The reason for this is that if the visible light transmittance is less than 65%, transparency decreases and use applications may be limited. On the other hand, if the visible light transmittance is high, the types of resins, solvents, etc. that can be used may be limited, or manufacturing variations may cause a sudden drop in yield. Note that the "light transmittance" referred to here means the average value of visible light transmittance when measured at wavelengths in the 380 to 780 nm wavelength range, changed in 1 nm increments, i.e., the average transmittance.

[0044] Therefore, it is more preferable that the visible light transmittance in the visible light region of wavelengths from 380 to 780 nm is set to a value within a range of 70 to 99%, and it is even more preferable that the visible light transmittance in the visible light region of wavelengths from 400 to 750 nm is set to a value within a range of 80 to 98%. The visible light transmittance of the infrared absorber is measured as an infrared absorbing filter in accordance with the conditions described in Example 1, etc., which will be described later, and can also be controlled by the blending amount of at least the infrared absorber, which is component (A), under certain conditions, as shown in Figure 9.

[0045] (7) Polar Group The infrared absorbent preferably has at least one polar group selected from an amino group, a hydroxyl group, an epoxy group, and a carboxyl group at least on its surface. The reason for this is that when the infrared absorbent is mixed and dispersed in a predetermined resin, the predetermined polar group of the infrared absorbent reacts appropriately with the reactive group of the predetermined resin, allowing the infrared absorbent to be firmly and uniformly dispersed in the predetermined resin.

[0046] Furthermore, it is also preferable that at least the surface of the infrared absorber has at least one polar group such as a phosphonic acid group, a catechol group, an acetylene group, a thiol group, or the like, either alone or together with these polar groups. This is because these polar groups also catalytically promote the reaction between an amino group or a hydroxyl group and a reactive group contained in a predetermined resin, or react alone with a reactive group contained in a predetermined resin, thereby enabling the infrared absorber to be firmly and uniformly dispersed in the predetermined resin.

[0047] The method for introducing polar groups into the infrared absorber is not particularly limited, but can be easily introduced, for example, by thermally decomposing the infrared absorber in a dispersion medium having a predetermined polar group. More specifically, as described below, at least one precursor of the infrared absorber is uniformly mixed with a solvent having a boiling point of 250°C or higher and having a predetermined polar group, and then the precursor is thermally decomposed to oxidize and generate the infrared absorber as nanoparticles, whereby a predetermined polarity due to the solvent can be introduced to the surface. Specifically, as shown in Figure 1 (c), a portion of the surface of the nanoparticles reacts with the solvent, thereby introducing the desired polarity to the surface of the nanoparticles.

[0048] (8) Manufacturing Method A suitable manufacturing method for the infrared absorber will be specifically described in the third embodiment. Briefly, the infrared absorber can basically be manufactured by sequentially performing steps (1) and (2), for example. That is, first, in step (1), a container is charged with at least one transparent conductive oxide precursor and a polar solvent having a boiling point of 250°C or higher. Next, in step (2), the temperature inside the container is adjusted to a temperature below the boiling point of the polar solvent, 250 to 350°C, to oxidatively decompose the transparent conductive oxide precursor and convert it into a compound having a polar group at least on its surface. In this way, it is preferable to produce nanoparticles derived from the transparent conductive oxide as the infrared absorber.

[0049] 2. Component (B) (Resin Component) (1) Types When the resin component is primarily a thermoplastic resin, preferred examples include at least one of polystyrene (PS) resin, polyacrylic resin (including methyl methacrylate (PMMA) resin), polyvinyl butyral (PVB) resin, polyvinyl formal (PVH) resin, polyvinyl alcohol (PVA) resin, polyester resin (PES), polycarbonate (PC) resin, etc. This is because such thermoplastic resins are soluble in various solvents, have good usability, have high mechanical properties and heat resistance, and are also excellent in transparency (typically, a visible light transmittance of 90% or more).

[0050] In particular, polystyrene resins are preferred because they dissolve in various ketone-based solvents, are easy to use, have high mechanical properties, and are highly transparent (typically, a visible light transmittance of 93% or more), and are relatively inexpensive. Polyacrylic resins are preferred because they dissolve in ester-based solvents such as ethyl acetate, and are excellent in weather resistance, adhesion, transparency, and the like, and are relatively inexpensive. Polycarbonate resins are preferred because they dissolve in various solvents such as dichloromethane, are easy to use, have high mechanical properties and impact resistance, and are highly transparent (typically, a visible light transmittance of 95% or more). Furthermore, polyacetal resins, such as polyvinyl butyral (PVB) resin and polyvinyl formal (PVH) resin, are preferred because they are soluble not only in organic solvents but also in water and alcohol solvents, are environmentally friendly, and are easily and specifically adhere to glass plates and the like.

[0051] On the other hand, when the resin component is mainly a thermosetting resin, it is preferably, for example, a polycarbonate-based urethane acrylate, a polyester-based urethane acrylate, or a resin made of a polycarbonate-based urethane acrylate and an acrylic polyol.

[0052] Furthermore, when the resin component is primarily a photocurable resin, it is preferably a resin that has an energy quantum capable of crosslinking or polymerizing molecules in, for example, electromagnetic waves or charged particle beams, i.e., a resin that crosslinks or hardens when irradiated with ultraviolet rays or electron beams, etc. Specifically, it is preferable to use an appropriate resin selected from polymerizable monomers, polymerizable oligomers, prepolymers, etc. that have conventionally been used as photocurable resins.

[0053] Such thermosetting resins and photocurable resins are remarkably excellent in infrared absorption mechanical strength, durability, and solvent resistance, and in particular, photocurable resins can be formed in a relatively short time.

[0054] (2) Weight-Average Molecular Weight It is generally preferable to set the weight-average molecular weight (Mw) of the resin component to a value within the range of 5,000 to 800,000. The reason for this is that if the weight-average molecular weight is less than 5,000, the mechanical properties and heat resistance may be reduced, and manufacturing variations may result in a reduced yield. On the other hand, if the weight-average molecular weight exceeds 800,000, the types of resins and solvents that can be used may be limited, or when mixed and dispersed in a predetermined resin, the predetermined polar groups of the infrared absorber may have difficulty reacting appropriately with the reactive groups of the predetermined resin. Therefore, it is more preferable to set the weight-average molecular weight of the resin component to a value within the range of 10,000 to 500,000, and even more preferable to set it to a value within the range of 50,000 to 300,000.

[0055] The weight average molecular weight of the resin component can be measured as an average molecular weight converted into standard polystyrene using a GPC device.

[0056] Furthermore, with regard to the average molecular weight of the resin component, it is preferable to set the molecular weight distribution of weight average molecular weight (Mw) / number average molecular weight (Mn) to a value within the range of 1.1 to 2.5. The reason for this is that if the molecular weight distribution is less than 1.1, usable resin materials may be limited, or the production yield may decrease. On the other hand, if the molecular weight distribution exceeds 2.5, the types of usable resins, solvents, etc. may be limited, or when the infrared absorbent is mixed and dispersed in a predetermined resin, it may become difficult for a predetermined polar group of the infrared absorbent to react appropriately with a reactive group of the predetermined resin.

[0057] Therefore, it is more preferable that the molecular weight distribution of the weight average molecular weight (Mw) / number average molecular weight (Mn) in the resin component is set to a value within the range of 1.2 to 2.3, and even more preferably to a value within the range of 1.3 to 2.0.

[0058] (3) Surface Free Energy (Surface Tension) The surface free energy of the resin component is set to 50 mJ / cm ２ The reason for this is that the surface free energy of the resin component is preferably 50 mJ / cm ２ If the surface free energy of the resin component exceeds 25 to 45 mJ / cm, the types of resin components that can be used may be limited, or when the infrared absorber is mixed and dispersed in a predetermined resin, the predetermined polar group of the infrared absorber may have difficulty in appropriately reacting with the reactive group of the predetermined resin. However, if the surface free energy of the resin component is excessively small, it may be difficult to uniformly disperse and mix the infrared absorber in the predetermined resin. Therefore, it is necessary to set the surface free energy of the resin component to 25 to 45 mJ / cm. ２ More preferably, it is 30 to 42 mJ / cm ２ It is even more preferable to do the following:

[0059] (4) Amount of Blending Furthermore, Figure 5(a) shows the relationship between the blending amount of component (B) and the dispersion stability evaluation (relative value). As is clear from the characteristic curve in Figure 5(a), it is generally preferable to blend the amount of component (B) within the range of 5,000 to 15,000 parts by weight per 100 parts by weight of component (A). The reason for this is that if the blending amount of component (B) is less than 5,000 parts by weight, dispersion stability will decrease, and infrared absorption properties, or mechanical strength, durability, etc., may also decrease. On the other hand, if the blending amount of component (B) is more than 15,000 parts by weight, the blending amount of infrared absorber will be relatively small, which may result in a decrease in infrared absorption properties.

[0060] Therefore, the blending amount of the resin component is preferably set to a value within the range of 6,000 to 13,000 parts by weight, and more preferably a value within the range of 8,000 to 12,000 parts by weight, of component (B) per 100 parts by weight of component (A).

[0061] 3. Component (C) (Solvent for Resin Component) (1) Type The type of solvent for the resin component is not particularly limited as long as it is a good solvent for the resin component, but for example, ketone solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), acetone, etc. are preferred. In order to adjust the solubility and boiling point of the resin component, it is also preferred to use organic solvents such as toluene, chloroform, tetrahydrofuran (THF), dichloromethane, methanol, ethanol, etc. alone or in combination with a ketone solvent.

[0062] (2) Amount of Blending Figure 5(b) also shows an example of the relationship between the amount of blending component (C) and the dispersion stability evaluation (relative value). As is clear from Figure 5(b), it is usually preferable to set the blending amount of the solvent for the resin component to a value within the range of 22,000 to 80,000 parts by weight of the blending amount of component (C) per 100 parts by weight of component (A). The reason for this is that if the blending amount of component (C) is less than 22,000 parts by weight, the dispersion stability and the solubility of the resin component will decrease, and when the infrared absorbent is mixed and dispersed in a predetermined resin, it may become difficult for the predetermined polar group of the infrared absorbent to react appropriately with the reactive group of the predetermined resin. On the other hand, if the amount of component (C) exceeds 80,000 parts by weight, the dispersion stability decreases and the solubility of the resin component improves, but conversely, when the infrared absorbent is mixed and dispersed in a predetermined resin, it may become difficult for the predetermined polar group of the infrared absorbent to react appropriately with the reactive group of the predetermined resin.

[0063] Therefore, the blending amount of the resin component is preferably set to a value within the range of 30,000 to 75,000 parts by weight, and more preferably a value within the range of 40,000 to 70,000 parts by weight, of component (C) per 100 parts by weight of component (A).

[0064] 4. Component (D) (Dispersion Aid for Infrared Absorbent) (1) Type A carboxyl group-containing compound is blended as component (D) as a dispersion aid for component (A). The reason for this is that when a carboxyl group-containing compound is introduced at least onto the surface of the infrared absorbent, the compounds react with each other and can be firmly and uniformly mixed and dispersed in the resin component.

[0065] Component (D) preferably contains at least one of an aromatic carboxylic acid, an alkyl carboxylate (the alkyl group has 1 to 28 carbon atoms), or an alkyl carboxylate ester (the alkyl group has 1 to 28 carbon atoms). More specifically, it is preferably at least one of 3-phenylpropionic acid, monomethyl malonate, monomethyl glutarate, monomethyl adipate, monomethyl azelate, monoethyl malonate, monoethyl glutarate, monoethyl adipate, monoethyl azelate, etc.

[0066] (2) Amount of Ingredient Added: Figure 5(c) shows the relationship between the amount of component (D) added and the dispersion stability evaluation (relative value). As is clear from Figure 5(c), it is generally preferable to set the amount of dispersion aid (component (D)) to a value within the range of 20 to 2,000 parts by weight per 100 parts by weight of component (A). This is because, when the amount of component (D) added is less than 20 parts by weight, dispersion stability decreases and, when the infrared absorbent is mixed and dispersed in a predetermined resin, the predetermined polar groups of the infrared absorbent may not react properly with the reactive groups of the predetermined resin. On the other hand, when the amount of component (D) added is more than 2,000 parts by weight, dispersion stability decreases and the mechanical properties of the formed infrared absorbing layer and its adhesion to a predetermined substrate may decrease.

[0067] Therefore, the amount of the dispersing aid (D) is preferably set to a value within the range of 30 to 1,500 parts by weight, and more preferably to a value within the range of 50 to 1,000 parts by weight.

[0068] 5. Infrared Absorption Maximum Wavelength Figures 4(a) to (d) are example light transmittance charts for infrared absorbing layers derived from different types of infrared absorbents. That is, as can be seen from these example light transmittance charts, it is generally preferable to set the absorption maximum wavelength of the infrared absorbent to a value within the range of 800 to 15,000 nm. The reason for this is that if the absorption maximum wavelength of such an infrared absorbent is less than 800 nm, the types of infrared absorbents that can be used may be limited. On the other hand, if the absorption maximum wavelength of such an infrared absorbent is greater than 15,000 nm, the absorbency of short-wavelength infrared rays, and therefore ultraviolet rays, may decrease.

[0069] Therefore, the maximum absorption wavelength of such an infrared absorbent is preferably set to a value within the range of 820 to 10,000 nm, and more preferably to a value within the range of 850 to 3,000 nm.

[0070] 6. Visible Light Transmittance Furthermore, the visible light transmittance of the infrared absorber is preferably 65% ​​or more in the visible light region of wavelengths from 380 to 780 nm (average transmittance; visible light transmittance is measured in 1 nm increments and the average value is used). The reason for this is that if the light transmittance in the visible light region is less than 65%, the transparency when observed with the naked eye decreases, which may limit applications. However, if the light transmittance in the visible light region exceeds 99%, the types and blending ratios of raw materials that can be used for the infrared absorber may be limited.

[0071] Therefore, the light transmittance in the visible light region is preferably set to a value within the range of 70 to 98%, and more preferably within the range of 80 to 95%.

[0072] 7. Other Compounding Components It is also preferable to add other compounding components to the resin composition for forming an infrared absorbing layer, as long as the other compounding components do not impair the effects of the present invention and can exhibit the desired effects. For example, the other compounding components may be at least one of an ultraviolet absorber, an antioxidant, a varnish, an antiblocking agent, a colorant, a coupling agent, an inorganic filler, an organic filler, etc.

[0073] In particular, when an organic ultraviolet absorber is blended, the desired ultraviolet blocking can be achieved with greater precision. Moreover, when the infrared absorber of the present invention is used in combination with an organic ultraviolet absorber, it has been found that the durability, heat resistance, etc. of the organic ultraviolet absorber are improved, presumably due to the properties of the infrared absorber. When an infrared absorber and an organic ultraviolet absorber are used in combination, the blending ratio is preferably within the range of 100 parts by weight: 0.01 to 80 parts by weight, more preferably within the range of 100 parts by weight: 0.1 to 30 parts by weight, and even more preferably within the range of 100 parts by weight: 0.5 to 10 parts by weight.

[0074] 8. Applications There are no particular limitations on the applications of the resin composition for forming an infrared absorbing layer, but suitable embodiments include configurations in which a predetermined level of infrared absorption is desired, such as in infrared shielding films, automobile window films, window films for buildings, films for solar power generation devices, CCD cameras, etc. For example, infrared shielding films and automobile window films typically have a two-layer structure of at least an infrared absorbing layer 20 and a substrate 22, as shown in Figure 6(a) , but as will be described later, this can be appropriately modified depending on the application of the infrared absorbing filter or automobile window film, as shown in Figures 6(b) to 6(e) .

[0075] [Second embodiment] The second embodiment of the present invention is an infrared absorbing filter comprising, on a substrate, an infrared absorbing layer derived from a resin composition for forming an infrared absorbing layer, the resin composition including: (A) component: nanoparticles derived from transparent conductive oxide as an infrared absorbent; (B) component: a resin component as a dispersion medium for the infrared absorbent; (C) component: a solvent for the resin component; and (D) component: a carboxyl group-containing compound as a dispersion aid for the infrared absorbent, wherein the infrared absorbing layer has a maximum absorption wavelength of 800 to 15,000 nm and has a light transmittance of 65% or more in the visible light region of 380 to 780 nm.

[0076] Hereinafter, examples of the configuration of the infrared absorbing filter will be described with reference to FIGS.

[0077] 1. Resin Composition for Forming Infrared-Absorbing Layer The resin composition for forming an infrared-absorbing layer used in the second embodiment can be the same as the resin composition for forming an infrared-absorbing layer used in the first embodiment, and therefore further description will be omitted. It should be noted that, in the resin composition for forming an infrared-absorbing layer used in this embodiment, it is preferable to set the amount of component (B) in the range of 5,000 to 15,000 parts by weight, the amount of component (C) in the range of 22,000 to 80,000 parts by weight, and the amount of component (D) in the range of 20 to 2,000 parts by weight, per 100 parts by weight of component (A). Furthermore, by using an infrared absorber having an absorption maximum wavelength in the range of 800 to 15,000 nm and a light transmittance in the visible light region of 380 to 780 nm of 65% or more, the absorption maximum wavelength and light transmittance of the infrared absorbing layer can be set to those values.

[0078] 6(a) to 6(e), the type of the substrate that constitutes a part of the infrared absorbing filter and on whose surface the infrared absorbing layer is formed directly or indirectly is not particularly limited, and can be appropriately changed depending on the application of the infrared absorbing filter. For example, it is preferable that the substrate is made of at least one general-purpose resin such as polyester resin, acrylic resin, polycarbonate resin, urethane resin, olefin resin, polyvinyl chloride resin, acetal resin, fluororesin, or silicone resin.

[0079] In particular, polyester resins (PET resins, etc.) are suitable substrate resin materials because they are excellent in mechanical strength, durability, smoothness, transparency, etc., and are relatively inexpensive. Also, acrylic resins are suitable substrate resin materials because they are particularly excellent in mechanical strength, weather resistance, etc., and are relatively inexpensive.

[0080] (2) Thickness The thickness of the infrared absorbing filter can be appropriately changed depending on the application, etc., but is usually preferably set to a value within the range of 50 to 500 μm. The reason for this is that by controlling the thickness within this range, the infrared absorbing filter can easily exhibit various properties and can also be easily manufactured.

[0081] Therefore, the thickness of the infrared absorbing filter is more preferably set to a value within the range of 80 to 400 μm, even more preferably set to a value within the range of 100 to 300 μm, and most preferably set to a value within the range of 120 to 250 μm.

[0082] (3) Shape The shape of the infrared absorbing filter is not particularly limited, and may be, for example, a tape, a triangle, a square (rectangle), a polygon, a circle, an ellipse, an irregular shape, or the like.

[0083] (4) Functional Layer It is usually preferable that the infrared absorbing filter has a release sheet on one or both sides as a kind of functional layer. For example, the release sheet can effectively protect the infrared absorbing filter from surrounding dust and dirt during storage and transportation until the infrared absorbing filter is actually used. Therefore, it can be suitably used as an automobile heat shielding film to be attached to the window of a vehicle, etc. Furthermore, if a release sheet is provided on one or both sides, it can also improve handling, alignment, attachment work, etc.

[0084] The other functional layers include at least one of a decorative layer, a decorative layer, an anti-blocking layer, a weather-resistant layer, and the like.

[0085] 3. Configuration Examples The configuration example of the infrared absorbing filter can be appropriately changed depending on various applications, but for example, as shown in Figure 6(a), a typical example is a configuration in which a predetermined infrared absorbing layer is formed on the surface of a predetermined substrate. Furthermore, as shown in Figure 6(b), a configuration in which an adhesive layer is provided on the back surface of the predetermined substrate is also a preferred configuration example, as it provides good adhesion and is easy to use as the above-mentioned automotive heat shielding film, etc. Furthermore, as shown in Figure 6(c), a configuration in which various functional layers are provided on the surface of the predetermined infrared absorbing layer to improve protection function, infrared absorption, etc. is also preferred.

[0086] Furthermore, as shown in Figure 6(d), depending on the application, etc., a multilayer structure of the specified infrared absorbing layer, for example, a structure of 2 to 10 layers or a structure of 3 to 8 layers, is also suitable for improving infrared absorbency or imparting antistatic functionality. Moreover, as shown in Figure 6(e), by patterning the specified infrared absorbing layer and arranging it to have a predetermined pattern, a preferable structure is achieved because it further improves the balance of properties among transparency, infrared absorbency, and economy. This is because even when the amount of the resin composition for forming an infrared absorbing layer is relatively reduced to improve transparency, it may be easier to control the aggregation prevention properties of the resin composition for forming an infrared absorbing layer, or a decrease in infrared absorbency may be more effectively prevented.

[0087] 4. Various Properties (1) Infrared Absorption The maximum absorption wavelength of the infrared absorbing layer in the infrared absorbing filter is measured in accordance with JIS K 0117, and is preferably set to a value usually within the range of 800 to 15,000 nm. The reason for this is that, although it depends on the configuration of the infrared absorbing filter, if the maximum absorption wavelength of the infrared absorbing layer is a value less than 800 nm, infrared absorption may decrease and the heat-shielding effect may decrease. On the other hand, if the maximum absorption wavelength of such an infrared absorbing layer is a value greater than 15,000 nm, the absorbency of short-wavelength infrared and ultraviolet rays may decrease.

[0088] Therefore, it is more preferable that the maximum absorption wavelength of the infrared absorbing layer in the infrared absorbing filter is set to a value within the range of 850 to 10,000 nm, and even more preferably to a value within the range of 880 to 5,000 nm.

[0089] (2) Visible Light Transmittance The visible light transmittance of the infrared absorbing layer in the infrared absorbing filter is preferably 65% ​​or more in the visible light region of wavelengths 380 to 780 nm measured in accordance with JIS A 5759. The reason for this is that if the visible light transmittance is less than 65%, transparency may decrease and applications may be limited. On the other hand, if the visible light transmittance is excessively high, the types of resins, solvents, etc. that can be used may be limited, or production variations may result in a reduced yield.

[0090] Therefore, it is more preferable that the visible light transmittance of the infrared absorbing layer in the infrared absorbing filter is 70% or more, and even more preferable that it is 80% or more.

[0091] (3) Heat Resistance As an index of the heat resistance of an infrared absorbing filter, it is preferable that the melting point of the resin component, measured in accordance with JIS K 7121, is a value of 150°C or higher. The reason for this is that if the resin component has such a melting point, it can usually withstand use of the infrared absorbing filter in a temperature range of about 100°C, and therefore can stably exhibit good infrared absorption properties. However, if the melting point of the resin component is excessively high, it may become difficult to mix and disperse it with an infrared absorbent, the types that can be used may be excessively limited, and further, the cost may increase, which may be economically disadvantageous.

[0092] Therefore, it is more preferable that the melting point of the resin component constituting the infrared absorbing filter is set to a value within the range of 160 to 300°C, and even more preferably to a value within the range of 180 to 280°C.

[0093] (4) Flexibility As one of the mechanical properties that serves as an index of the durability of the infrared absorbing filter (corresponding to a thickness of 1 mm), the flexibility of the infrared absorbing layer measured in accordance with JIS K 5600-5-1 (mandrel test) is preferably set to a value of 32 mm or less in diameter. The reason for this is that if the diameter of the cylindrical rod that meets the pass criteria in such a mandrel test exceeds 32 mm, the applications of the infrared absorbing filter may be limited and the durability in actual use, including bending, may be reduced.

[0094] Therefore, it is more preferable that the diameter of the cylindrical rod that meets the pass criteria in such a mandrel test is 25 mm or less, and even more preferable that it is 20 mm or less.

[0095] (5) Tensile Modulus As one of the mechanical strength characteristics of the infrared absorbing filter, the tensile modulus (Young's modulus) of the infrared absorbing layer measured in accordance with JIS K 7161 is preferably set to a value within the range of 1,000 to 10,000 MPa. This is because such a tensile modulus provides appropriate mechanical properties and good durability, and ultimately enables the filter to exhibit good infrared absorption more stably. More specifically, if the tensile modulus is less than 1,000 MPa, the applications of the infrared absorbing filter may be limited, and the durability and mechanical properties in actual use may be reduced. On the other hand, if the tensile modulus exceeds 10,000 MPa, bending or curving may become difficult, limiting the applications of the infrared absorbing filter and limiting the types of resin components that can be used.

[0096] Therefore, the tensile modulus of elasticity of the infrared absorbing layer in the infrared absorbing filter is more preferably set to a value within the range of 2,000 to 8,000 MPa, and even more preferably set to a value within the range of 3,000 to 6,000 MPa.

[0097] (6) Tensile Elongation As one of the mechanical strength properties of the infrared absorbing filter, it is preferable that the tensile elongation of the infrared absorbing layer measured in accordance with JIS K 7113 is set to a value within a range of 25 to 120%. The reason for this is that if the infrared absorbing filter has such a tensile elongation, it will exhibit appropriate mechanical properties, and will be able to be attached to curved glass or the like while conforming to it, and will therefore be able to exhibit good infrared absorption properties more stably.

[0098] Therefore, the tensile elongation of the infrared absorbing layer in the infrared absorbing filter is more preferably set to a value within the range of 30 to 100%, and even more preferably set to a value within the range of 50 to 80%.

[0099] (7) Electrical Characteristics (Surface Resistance) As one of the electrical characteristics of the infrared absorbing filter, it is possible to measure the current flowing through the surface of the test object by pressing a ring electrode (outer electrode) and a main electrode (inner electrode) against the surface of the test object. In addition, by placing a back electrode under the test object, it is possible to confirm that only the current flowing through the surface of the test object is measured. The surface resistance measured in this way, especially the surface resistance of the infrared absorbing layer, is measured as 1×10 ６ ~1 x 10 １３ It is preferable that the surface resistance is set to a value within the range of Ω / □. The reason for this is that if the surface resistance is in this range, the infrared absorbing filter can exhibit good antistatic properties, reduce adhesion of dust and the like, and can easily function as an electrode to which a ground or the like can be connected.

[0100] Therefore, the surface resistance of the infrared absorbing filter (infrared absorbing layer) is set to 1×10 ８ ~1 x 10 １２ It is more preferable that the value is in the range of Ω / □, and 1×10 ９ ~1 x 10 １１ It is more preferable to set the value within the range of Ω / □.

[0101] (8) Pattern characteristics It is preferable that the infrared absorbing filter has an infrared absorbing layer derived from a resin composition for forming an infrared absorbing layer, which comprises nanoparticles derived from transparent conductive oxide as an infrared absorber, a resin component (B) as a dispersion medium for the infrared absorber, a solvent for the resin component (C), and a carboxyl group-containing compound as a dispersion aid for the infrared absorber (D), and the infrared absorbing layer is arranged in a patterned state on a substrate. This is because the infrared absorber contained in the infrared absorbing layer is patterned to effectively prevent aggregation of the infrared absorber, and therefore, even with the use of a relatively small amount, better infrared absorption properties can be easily obtained while maintaining high transparency.

[0102] Here, the patterning of the infrared absorbing layer is typically in the form of letters, figures, symbols, or a combination thereof. More specifically, it is usually preferred that the pattern has at least one planar shape such as a circle, triangle, square, or dot shape such as a pentagon to octagon, a line shape such as a single line, double line, or wavy line, an irregular shape, a ladder shape, a doughnut shape with a hole, a predetermined number, or a predetermined design.

[0103] Furthermore, when patterning the infrared absorbing layer, the formation method is not particularly limited, but it is usually preferable to adopt at least one of various pattern printing methods such as offset printing, inkjet printing, screen printing, and roll printing via a perforated filter corresponding to the pattern.

[0104] Furthermore, in patterning the infrared absorbing layer, it is also preferable to combine a method in which unevenness is provided in advance on the surface of the substrate, and the infrared absorbing agent is embedded into the unevenness by utilizing its specific gravity or shape, as shown in FIGS. 8(a) to 8(e).

[0105] More specifically, as shown in FIG. 8( a), a substrate (release substrate) 30 is first prepared, the surface of which is pre-formed with irregularities. The type of substrate can be varied as needed depending on the application, but is typically at least one of polyethylene resin film, polypropylene resin film, fluororesin film, polyester resin film, and silicone release agent-treated film. The thickness of the substrate is typically preferably within a range of 10 to 1,000 μm, more preferably within a range of 20 to 300 μm, and even more preferably within a range of 25 to 150 μm. This is because, as long as the substrate thickness is within the specified range, it is easy to form irregularities with a maximum depth (t1) of 1 to 200 μm relative to the surface and a spacing (t2) between adjacent irregularities of 20 to 500 μm, and the substrate is easy to handle.

[0106] 8(b), a dispersion liquid containing the infrared absorbent 12 or the infrared absorbent itself is applied to the surface of the substrate having the irregularities. Then, depending on the specific gravity and form of the infrared absorbent, the infrared absorbent applied to the irregularities of the substrate slides down and eventually gathers in the irregularities of the substrate, forming a predetermined pattern corresponding to the irregularities of the substrate.

[0107] Next, as shown in Fig. 8(c), a resin film 34 having a pressure-sensitive adhesive layer 32 is laminated on the surface side of the aggregated infrared absorbent having a predetermined pattern. As a result, it is preferable to form a patterned layer containing the infrared absorbent, as shown in Fig. 8(d) and (e), respectively, when viewed from the side and when viewed from the side with the irregularities.

[0108] 8(c), the adhesive solution for forming the adhesive layer may be applied to the infrared absorbent in a predetermined pattern, and the solvent may be dried and removed to leave only the infrared absorbent. Next, a predetermined resin film may be further laminated on top of the patterned infrared absorbent to form a patterned layer containing the infrared absorbent.

[0109] [Third Embodiment] The third embodiment of the present invention is a method for producing a resin composition for forming an infrared absorbing layer, the method comprising: (A) component (A) nanoparticles derived from a transparent conductive oxide as an infrared absorber; (B) component (B) resin component as a dispersion medium for the infrared absorber; (C) component (C) solvent for the resin component; and (D) component (D) carboxyl group-containing compound as a dispersion aid for the infrared absorber, the method comprising the following steps (1) to (3): (1) a step of placing at least one raw material (precursor) of the transparent conductive oxide and a polar solvent having a boiling point of 250°C or higher in a container; and (2) a step of setting the temperature inside the container to 250 to 350°C, hydrolyzing and / or oxidizing the raw material of the transparent conductive oxide, and producing nanoparticles derived from the transparent conductive oxide as an infrared absorber, the nanoparticles having polar groups at least on their surfaces. (3) A step of extracting nanoparticles derived from the transparent conductive oxide, mixing and dispersing them in a predetermined ratio of 5,000 to 15,000 parts by weight of component (B), 22,000 to 80,000 parts by weight of component (C), and 20 to 2,000 parts by weight of component (D) relative to 100 parts by weight of component (A) to obtain a resin composition for forming an infrared absorbing layer.

[0110] The following description will be given with reference to the flow chart shown in FIG. 7 for explaining the method for manufacturing an infrared absorbing filter.

[0111] (1) Step of preparing a resin composition for forming an infrared absorbing layer This step is to place a precursor serving as a raw material for a transparent conductive oxide, such as at least one of a metal complex, an organometallic complex, a metal salt, a metal compound, a metal precursor, and the like, and a polar solvent having a boiling point of 250°C or higher, into a container.

[0112] As raw materials for transparent conductive oxides, it is usually preferable to use AcAcIn, AcAcSn, AcAcZn, an In precursor, an Sn precursor, a Zn precursor, etc. Furthermore, as solvents for introducing polar groups, it is preferable to use oleic acid (boiling point: 360°C), oleylamine (boiling point: about 350°C), dodecylamine (boiling point: about 250°C), etc.

[0113] (2) Infrared absorbing agent formation process This is a process in which the temperature inside the reaction vessel (flask, etc.) is set to a temperature lower than the boiling point of the polar solvent, 250 to 350°C, or a lower temperature, to hydrolyze and / or oxidatively decompose the raw material of the transparent conductive oxide, and to produce nanoparticles derived from the transparent conductive oxide as an infrared absorbing agent, which have polar groups at least on their surfaces.

[0114] First, the reaction vessel containing the raw materials is placed under vacuum and preferably heated at 150°C for 2 hours, with one nitrogen purge during the process. Next, the reaction vessel is preferably heated in nitrogen, for example, to 290°C, to carry out the In-oleate reaction and the Sn-oleate reaction. Next, once these oleate reactions are complete, a metal precursor is drawn into the reaction vessel using a syringe and slowly injected into the reaction vessel, thereby producing nanoparticles derived from the transparent conductive oxide. It has been found that the size (average particle size) of the resulting nanoparticles derived from the transparent conductive oxide can be altered by appropriately changing the injection amount and injection rate of the metal precursor.

[0115] (3) Step of forming a resin composition for forming an infrared absorbing layer Next, it is preferable to carry out a step of weighing out (A) nanoparticles as an infrared absorber, (B) a resin component, (C) a solvent for the resin component, and (D) a dispersing aid so as to be in a predetermined ratio, and then adding them to form a resin composition for forming an infrared absorbing layer. Here, it is preferable to take out the nanoparticles derived from the transparent conductive oxide as the infrared absorber (A) from the reaction vessel and appropriately carry out a washing treatment with alcohol or the like.

[0116] First, nanoparticles derived from transparent conductive oxide (A) as an infrared absorber, a resin component (B), a solvent for the resin component (C), and a dispersing aid (D) are weighed and placed in a mixing vessel equipped with a stirrer so as to be in a predetermined ratio. Next, in the mixing vessel equipped with a stirrer, the components (A) to (D) are uniformly mixed while stirring under predetermined conditions to obtain a resin composition for forming an infrared-absorbing layer. It is also preferable to prepare a masterbatch rich in the infrared absorber (A) in advance, and then blend the components (B) to (D) based on this to finally obtain a resin composition for forming an infrared-absorbing layer in a predetermined ratio.

[0117] (4) Lamination step (printing step) of infrared absorbing layer-forming resin composition Next, it is preferable to mix and disperse the infrared absorbing transparent conductive oxide-derived nanoparticles as component (A), component (B), component (C), and component (D) in a predetermined ratio to obtain a predetermined infrared absorbing layer-forming resin composition, and then to carry out a step of laminating the obtained resin composition on a predetermined substrate to form an infrared absorbing layer (coating film) of uniform thickness on the substrate.

[0118] When forming a coating film of uniform thickness, it is preferable to use at least one of letterpress printing, intaglio printing, roll coating, calendar printing, electrostatic coating, brush coating, transfer method, etc. On the other hand, when forming a patterned coating film of uniform thickness (line-like, dot-like, picture-like, letter-like, figure-like, symbol-like, or a combination thereof), a screen printing method, an inkjet method, or a coating method using a perforated pattern is a suitable lamination method because it allows coating to any desired location.

[0119] (5) Inspection Step Depending on the application, it is preferable to appropriately carry out a step of inspecting the infrared absorbing layer formed on a predetermined substrate for thickness, appearance (including dispersibility), infrared absorption, visible light transmittance, ultraviolet light transmittance, glossiness, weather resistance, heat resistance, mechanical properties, electrical properties (electrical insulation), surface hardness, and FT-IR, respectively, with the predetermined substrate included or with the predetermined substrate removed.

[0120] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these descriptions without any particular reason.

[0121] [Example 1] 1. Preparation of infrared-absorbing layer-forming resin composition and infrared-absorbing filter using same (1) Preparation process of infrared-absorbing layer-forming resin composition In a 1-liter stainless steel container, 100 parts by weight of indium (II) acetate as a transparent conductive oxide precursor, 15,600 parts by weight of tin (II) 2-ethylhexanoate, 160 parts by weight of 2-ethylhexanoic acid as a reaction material, 2,530 parts by weight of n-octyl ether as a solvent, and 25 parts by weight of oleylamine (boiling point 348 ° C.) as a polar group introduction solvent were placed in a ratio of. Note that the blending ratio of each raw material was as described above, but each was weighed so that the amount of the obtained infrared-absorbing layer-forming resin composition was 900 g, and each raw material was placed in a stainless steel container.

[0122] (2) Preparation of infrared absorber Next, the inside of the stainless steel container containing the raw materials was stirred under vacuum conditions at 80°C for 30 minutes, and then N ２ The temperature was raised to 150°C under these conditions and maintained at that temperature for 1 hour. ２ The mixture was stirred for 2 hours at 280°C while being maintained under these conditions. After that, it was cooled to room temperature, and 280 parts by weight of oleylamine was added to 100 parts by weight of indium (II) acetate. The raw materials were allowed to react with each other while stirring for 30 minutes. That is, the raw materials of the transparent conductive oxide were hydrolyzed and / or oxidatively decomposed, and nanoparticles derived from transparent conductive oxide (ITO) having polar groups at least on their surfaces were generated. Next, ITO nanoparticles (doped amount 0.01%, average particle size: 10 nm) as an infrared absorber having amino groups, which are polar groups, at least on their surfaces were obtained from the inside of the stainless steel container, removed, and washed with ethanol.

[0123] (3) Preparation of infrared absorbing layer-forming resin composition Next, in a 500 cc glass container, 8,200 parts by weight (solid content equivalent) of polystyrene (weight average molecular weight: 280,000, hereinafter sometimes referred to as polystyrene 1) as component (B), 38,600 parts by weight (solid content equivalent) of solvent (MEK) as component (C), and 70 parts by weight (solid content equivalent) of 3-phenylpropionic acid as a dispersing aid for component (D) were placed in a ratio of 100 parts by weight of the obtained ITO nanoparticles as an infrared absorber. Next, the mixture was mixed and dispersed until uniform, to obtain a resin composition for forming an infrared absorbing layer containing an infrared absorber.

[0124] (4) Film-forming step / printing step Next, the obtained resin composition for forming an infrared absorbing layer was applied onto a PET film that had been subjected to an easy-adhesion treatment using a bar coater No. 10. Next, the coating was dried by heating at 80°C for 10 minutes to form an infrared absorbing layer having a thickness of 5 µm. The film thickness was confirmed by measurement with a micrometer.

[0125] 2. Evaluation of Resin Composition for Forming Infrared Absorbing Layer and Infrared Absorbing Filter (1) Dispersion Stability The dispersion stability of the infrared absorber in the resin composition for forming the infrared absorbing layer was evaluated based on changes in state when stored in a glass container at room temperature according to the following criteria. Evaluation was based on changes in state when stored in a glass container. Excellent: No changes in appearance (precipitation or clouding) were observed even after 72 hours or more. Excellent: No changes in appearance (precipitation or clouding) were observed up to 48 hours, but changes in appearance (precipitation or clouding) were observed after 48 hours or more. Good: No changes in appearance (precipitation or clouding) were observed up to 24 hours, but changes in appearance (precipitation or clouding) were observed after 24 hours or more. Fair: No changes in appearance (precipitation or clouding) were observed up to 6 hours, but changes in appearance (precipitation or clouding) were observed after 6 hours or more. Poor: Changes in appearance (precipitation or clouding) were observed in less than 6 hours. The above-mentioned evaluations of excellent, good, good, fair, and poor correspond to evaluation values ​​of approximately 5, 4, 3, 1-2, and 0 on the vertical axis of FIG. 5, respectively.

[0126] (2) Transparency (visible light transmittance) The transparency of the infrared absorbing layer was evaluated. That is, the resin composition for forming an infrared absorbing layer was formed into a film having a thickness of 100 μm in a PTFE petri dish, and the solvent was dried and removed, and then the infrared absorbing layer was peeled off, and the light transmittance in the visible light region was measured. The transparency was evaluated according to the following criteria. Excellent: Light transmittance is 80% or more. Good: Light transmittance is 65% or more and less than 80%. Fail: Light transmittance is 40% or more and less than 65%. Poor: Light transmittance is less than 40%, or a film could not be formed and evaluation was not possible.

[0127] (3) Infrared absorption properties (solar heat gain coefficient) The infrared absorption properties of the infrared absorbing layer were evaluated. That is, an infrared absorber layer having a thickness of 100 μm was prepared in the same manner as the transparency evaluation sample, and the solar heat gain coefficient was measured in accordance with the method of JIS R 3106, and the infrared absorption properties were evaluated according to the following criteria. The results are shown in Table 3. Excellent: The solar heat gain coefficient is 80% or less. Good: The solar heat gain coefficient is more than 80% and 85% or less. Fair: The solar heat gain coefficient is more than 85% and 90% or less. Poor: The solar heat gain coefficient is more than 90%, or a film could not be formed and evaluation was not possible.

[0128] (4) Film-forming ability / printing ability The film-forming ability / printing ability of the infrared absorbing layer obtained by the film-forming process / printing process was evaluated. That is, the film-forming ability / printing ability of the 5 μm-thick infrared absorbing layer obtained by the film-forming process / printing process was visually evaluated according to the following criteria. The results are shown in Table 3. Excellent: The thickness is uniform and the surface is smooth. Good: The thickness is slightly non-uniform, but the surface is smooth. Fair: The thickness is slightly non-uniform, and unevenness is observed in part of the surface. Poor: The thickness is non-uniform and unevenness is observed on the surface.

[0129] (5) Durability (Bending Properties) Regarding mechanical properties as an index of durability, bending properties were evaluated by a mandrel test. That is, in the same manner as in the transparency evaluation sample, an infrared absorber layer having a thickness of 5 μm was formed on a PET film, and the bending property was measured by a mandrel test measured in accordance with JIS K 5600-5-1. The bending property was measured with the PET film side facing inward, and evaluated according to the following criteria from the diameter of a cylindrical rod when a crack appeared in the outer infrared absorber layer. The obtained results are shown in Table 3. Excellent: The diameter of the cylindrical rod that meets the pass criteria is 20 mm or less. Good: The diameter of the cylindrical rod that meets the pass criteria is more than 20 mm and 25 mm or less. Fair: The diameter of the cylindrical rod that meets the pass criteria is more than 25 mm and 32 mm or less. Poor: The diameter of the cylindrical rod that meets the pass criteria is more than 32 mm.

[0130] In Example 2, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (component (D)) was monomethyl malonate, as shown in Table 1. The obtained results are shown in Table 3.

[0131] In Example 3, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (component (D)) was monoethyl malonate, as shown in Table 1. The obtained results are shown in Table 3.

[0132] In Example 4, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (component (D)) was monomethyl azelate, as shown in Table 1. The obtained results are shown in Table 3.

[0133] In Example 5, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (component (D)) was monomethyl adipate, as shown in Table 1. The obtained results are shown in Table 3.

[0134] In Example 6, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (component (D)) was monoethyl adipate, as shown in Table 1. The obtained results are shown in Table 3.

[0135] In Example 7, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the dispersing aid (D) was changed to monomethyl glutarate, as shown in Table 1. The obtained results are shown in Table 3.

[0136] In Example 8, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that a polystyrene resin having a weight-average molecular weight of 40,000 (hereinafter, sometimes referred to as polystyrene 2) was used as the polystyrene resin (B) as shown in Table 1. The obtained results are shown in Table 3.

[0137] In Example 9, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin as component (B) was reduced to 5,000 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0138] In Example 10, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin as component (B) was increased to 15,000 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0139] In Example 11, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the solvent for the resin component (C) was reduced to 22,000 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0140] In Example 12, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the solvent for the resin component (C) was increased to 80,000 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0141] In Example 13, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the dispersion aid for the infrared absorber, which is component (D), was reduced to 20 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0142] In Example 14, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the dispersion aid for the infrared absorber, which is component (D), was increased to 2,000 parts by weight as shown in Table 1. The obtained results are shown in Table 3.

[0143] In Example 15, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin (B) component was 11,700 parts by weight, the blending amount of the solvent for the resin component (C) component was 55,100 parts by weight, and the blending amount of the dispersion aid for the infrared absorber (D) component was 100 parts by weight, as shown in Table 1. The obtained results are shown in Table 3.

[0144] In Example 16, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin (B) component was 5,000 parts by weight, the blending amount of the solvent for the resin component (C) component was 22,700 parts by weight, and the blending amount of the dispersion aid for the infrared absorber (D) component was 40 parts by weight, as shown in Table 1. The obtained results are shown in Table 3.

[0145] Example 17 Example 17 was carried out by changing the component (B) to a methyl methacrylate (PMMA) resin (weight average molecular weight: 75,000, hereinafter sometimes referred to as PMMA1) as shown in Table 1. 14,100 parts by weight (solids equivalent) of PMMA1 (component (B)), 62,400 parts by weight (solids equivalent) of a solvent (MEK) (component (C)), and 115 parts by weight (solids equivalent) of 3-phenylpropionic acid, a dispersing aid for component (D), were blended relative to 100 parts by weight of ITO nanoparticles, and an infrared absorbing filter was produced and evaluated in the same manner as in Example 1. The obtained results are shown in Table 3.

[0146] In Example 18, an infrared absorbing filter was produced and evaluated in the same manner as in Example 17, except that the dispersing aid (component (D)) was monomethyl adipate, as shown in Table 1. The obtained results are shown in Table 3.

[0147] In Example 19, an infrared absorbing filter was produced and evaluated in the same manner as in Example 17, except that the methyl methacrylate resin of component (B) was changed to PMMA2 having a weight average molecular weight of 350,000, as shown in Table 1. The obtained results are shown in Table 3.

[0148] In Comparative Example 1, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin as component (B) was reduced to 4,000 parts by weight as shown in Table 2. The obtained results are shown in Table 3.

[0149] In Comparative Example 2, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin as component (B) was increased to 16,000 parts by weight as shown in Table 2. The obtained results are shown in Table 3.

[0150] In Comparative Example 3, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the solvent for the resin component (C) was increased to 90,000 parts by weight as shown in Table 2. The obtained results are shown in Table 3.

[0151] In Comparative Example 4, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the dispersion aid for the infrared absorber, which is component (D), was reduced to 15 parts by weight as shown in Table 2. The obtained results are shown in Table 3.

[0152] In Comparative Example 5, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the dispersion aid for the infrared absorber, which is component (D), was increased to 2,100 parts by weight as shown in Table 2. The obtained results are shown in Table 3.

[0153] In Comparative Example 6, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin (B) component was 16,400 parts by weight, the blending amount of the solvent for the resin component (C) component was 77,200 parts by weight, and the blending amount of the dispersion aid for the infrared absorber (D) component was 140 parts by weight, as shown in Table 2. The obtained results are shown in Table 3.

[0154] In Example 7, an infrared absorbing filter was produced and evaluated in the same manner as in Example 1, except that the blending amount of the polystyrene resin (B) component was 4,500 parts by weight, the blending amount of the solvent for the resin component (C) component was 21,400 parts by weight, and the blending amount of the dispersion aid for the infrared absorber (D) component was 39 parts by weight, as shown in Table 2. The obtained results are shown in Table 3.

[0155]

[0156]

[0157]

[0158] In Examples 20 and 21, the polystyrene resin as component (B) was replaced with a polyvinyl butyral resin having an average molecular weight of 50,000 and a polyvinyl formal resin having an average molecular weight of 80,000, respectively, and MEK / toluene (blending ratio: 50 / 50) was used as the solvent type as component (C). Except for these, infrared absorbing filters were produced and evaluated in the same manner as in Example 1.

[0159] As a result, it was confirmed that in Examples 20 and 21, good dispersibility (excellent), transparency (excellent), infrared absorption (excellent), film-forming property / printability (excellent), and bending property (excellent) were obtained.

[0160] In Examples 22 and 23, the infrared absorbing layer was formed by patterning into dots in accordance with the method shown in Figures 8(a) to 8(d) (average dot diameter: 10 µm, distance between adjacent dot centers: 50 µm). That is, in Examples 22 and 23, an acrylic resin with an average molecular weight of 500,000 and an acrylic resin with an average molecular weight of 800,000 were used as component (B), and ethyl acetate was used as the solvent species (component (C)). Furthermore, when patterning the infrared absorbing layer into dots, the blending amount of component (B) was 15,000 parts by weight, and the blending amount of solvent species (component (C)) was 38,600 parts by weight, relative to 100 parts by weight of component (A).

[0161] As a result, it was confirmed that in Examples 22 and 23, despite the fact that the relative amount of the infrared absorber (component (A)) used was small, good dispersibility (excellent), transparency (excellent), infrared absorbency (excellent), film-forming property / printability (excellent), and bending property (excellent) were each obtained.

[0162] As described above in detail, according to the infrared-absorbing layer-forming resin composition etc. of the present invention, by using nanoparticles derived from an inorganic material as the infrared absorbent and by using a predetermined dispersing aid etc., it has become possible to obtain an infrared-absorbing layer-forming resin composition that is excellent in dispersion stability, transparency, durability, and further printing properties, even when mixed and dispersed in a non-polar resin etc. In other words, by using components (A) to (C) in predetermined proportions and further using a predetermined proportion of a dispersing aid etc. as component (D), it has become possible to obtain an infrared-absorbing layer-forming resin composition etc. that is excellent in dispersion stability, transparency, printing properties, etc., even when mixed and dispersed in a non-polar resin etc.

[0163] Therefore, by uniformly blending predetermined nanoparticles or the like, which are the infrared absorber of component (A), into a resin, or by solid printing or pattern printing on a predetermined substrate as shown in Figures 6(a) to 6(e), an infrared absorbing layer can be formed, which can efficiently block infrared rays of a predetermined wavelength while maintaining relatively high transparency.

[0164] Furthermore, by kneading or embedding predetermined nanoparticles or the like, which are the infrared absorber of component (A), into a predetermined base material, or by forming a three-layer sandwich structure consisting of a layer not containing component (A), a layer containing component (A), and a layer not containing component (A), a base material containing an infrared absorber can be added separately from or as part of the infrared absorbing layer, thereby making it possible to more efficiently block infrared rays of a predetermined wavelength.

[0165] Therefore, according to the present invention, a wide range of applications are expected, including infrared-enhancing films for solar power generation devices, heat-shielding films for window glass, heat-shielding films for automobiles, heat-shielding protective films for trains and airplanes, window films, heat-shielding protective films for office buildings, protective films for CCD cameras, antistatic films, protective films for infrared-shielding paints, protective films for products degraded by infrared rays, temperature-rise suppression films for chemical containers, packaging films for frozen goods, temperature-rise suppression films for refrigerated goods, and protective films.

[0166] DESCRIPTION OF SYMBOLS 10: Infrared absorber 12: Nanoparticles 14: Dispersion aid 16: Resin component 18: Infrared absorbing filter 20: Infrared absorbing layer 22: Substrate 24: Pressure-sensitive adhesive layer 26: Functional layer 30: Release substrate 32: Pressure-sensitive adhesive layer 34: Resin film

Claims

1. A resin composition for forming an infrared absorbing layer, comprising: component (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbing agent; component (B) a resin component as a dispersion medium for the infrared absorbing agent; component (C) a solvent for the resin component; and component (D) a carboxyl group-containing compound as a dispersion aid for the infrared absorbing agent, wherein the amount of component (B) blended is within a range of 5,000 to 15,000 parts by weight, the amount of component (C) blended is within a range of 22,000 to 80,000 parts by weight, and the amount of component (D) blended is within a range of 20 to 2,000 parts by weight, relative to 100 parts by weight of component (A).

2. The resin composition for forming an infrared absorbing layer according to claim 1, characterized in that the component (A) is ITO nanoparticles having an average particle size within the range of 0.1 to 100 nm and having at least one polar group selected from an amino group, a hydroxyl group, an epoxy group, and a carboxyl group, at least on the surface.

3. The component (B) is 50 mJ / m 2 2. The resin composition for forming an infrared absorbing layer according to claim 1, which is a thermoplastic resin having a surface free energy below 100 nm.

4. The resin composition for forming an infrared absorbing layer according to claim 1, wherein the component (C) contains at least one ketone solvent.

5. The resin composition for forming an infrared absorbing layer according to claim 1, characterized in that the component (D) contains at least one of an aromatic carboxylic acid, an alkyl carboxylate (the alkyl group has 1 to 28 carbon atoms), and an alkyl carboxylate ester (the alkyl group has 1 to 28 carbon atoms).

6. An infrared absorbing filter comprising an infrared absorbing layer on a substrate, the infrared absorbing layer being derived from a resin composition for forming an infrared absorbing layer, the resin composition comprising: (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbing agent; (B) a resin component as a dispersion medium for the infrared absorbing agent; (C) a solvent for the resin component; and (D) a carboxyl group-containing compound as a dispersion aid for the infrared absorbing agent, the infrared absorbing filter being characterized in that the infrared absorbing layer has a maximum absorption wavelength in the range of 800 to 15,000 nm and a light transmittance of 65% or more in the visible light region of 380 to 780 nm.

7. The infrared absorbing filter according to claim 6, wherein the infrared absorbing layer is disposed on the substrate so as to have a predetermined pattern.

8. A method for producing a resin composition for forming an infrared absorbing layer, comprising: component (A) nanoparticles derived from a transparent conductive oxide as an infrared absorbent; component (B) a resin component as a dispersion medium for the infrared absorbent; component (C) a solvent for the resin component; and component (D) a carboxyl group-containing compound as a dispersion aid for the infrared absorbent, the method comprising the following steps (1) to (3): (1) A step of placing at least one transparent conductive oxide precursor and a polar solvent having a boiling point of 250° C. or higher in a container. (2) A step of setting the temperature in the container to 250 to 350° C., oxidatively decomposing the transparent conductive oxide precursor, and generating transparent conductive oxide-derived nanoparticles as an infrared absorber having a polar group at least on the surface. (3) A step of taking out the transparent conductive oxide-derived nanoparticles, mixing and dispersing them in a predetermined ratio of 5,000 to 15,000 parts by weight of component (B), 22,000 to 80,000 parts by weight of component (C), and 20 to 2,000 parts by weight of component (D) relative to 100 parts by weight of component (A) to obtain the infrared absorbing layer-forming resin composition.

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