WO2017104313A1 - Optical film - Google Patents

Abstract

The objective of the present invention is to provide an optical film which contains vanadium dioxide-containing particles and is not susceptible to the influence of the environment of usage, and wherein the near-infrared light shielding rate is able to be adjusted in accordance with the temperature environment. An optical film (1) according to the present invention is characterized by: having an optical function layer (3), which contains vanadium dioxide-containing particles having thermochromic properties, on a transparent base (2); and having at least one transparent thermal insulation layer (5) on a surface of the optical function layer (3), said surface being on the reverse side of the transparent base (2)-side surface.

Description

Optical film

The present invention relates to an optical film, and more particularly to an optical film containing vanadium dioxide-containing particles capable of adjusting the near-infrared light shielding rate in accordance with a temperature environment and hardly affected by the use environment.

In recent years, laminated glass having high heat insulating property or heat insulating property, which blocks heat rays felt on human skin due to the influence of sunlight entering from a vehicle window, has been distributed in the market. Recently, with the spread of electric vehicles and the like, development of near-infrared light (heat ray) shielding films applied to laminated glass has been actively conducted from the viewpoint of increasing the cooling efficiency in the vehicle.
By applying the near-infrared light shielding film to the window glass of a vehicle body or a building, it is possible to reduce the load on the cooling equipment such as an air conditioner in the vehicle, which is an effective means for saving energy.

The near-infrared light shielding film is preferably used due to its high near-infrared light shielding ability in a low-latitude zone near the equator where the illuminance of sunlight is high. However, in the mid to high latitude winter seasons, conversely, there is a problem that sunlight is shielded when it is desired to take it into the vehicle or the room as much as possible.

In order to solve the above problem, a method of applying a thermochromic material that controls the optical properties of near-infrared light shielding and transmission to the near-infrared light shielding film has been studied. A typical example is vanadium dioxide (hereinafter also referred to as VO ₂ ). VO ₂ is known to undergo a phase transition in a temperature region around 67 ° C. and exhibit thermochromic properties. That is, the optical film using the characteristics of VO ₂ can exhibit characteristics such as shielding near infrared light that causes heat at high temperatures and transmitting near infrared light at low temperatures. . As a result, when the summertime is hot, near-infrared light is shielded to suppress the temperature rise in the room, and when the wintertime is cold, light energy can be taken in.

As a method for producing VO ₂ having such characteristics, a method of obtaining VO ₂ particles by hydrothermal synthesis of a vanadium compound and hydrazine or a hydrate thereof is disclosed (for example, Patent Document 1). reference.).
Further, it is disclosed that a thermochromic film can be provided by forming a VO ₂ dispersed resin layer in which a VO ₂ particle produced by hydrothermal synthesis is dispersed in a transparent resin on a transparent substrate to form a laminate. (For example, see Patent Document 2).

When such a thermochromic film is attached to a window and used in a place where the air conditioner wind (cold air) directly hits it, the temperature rise is suppressed even when it is originally intended to block near-infrared light. In some cases, the expected performance does not function due to the influence of the usage environment, such as the fact that it is not shielded.

JP 2011-178825 A JP 2013-184091 A

The present invention has been made in view of the above-described problems and situations, and its solution is an optical film containing vanadium dioxide-containing particles capable of adjusting the near-infrared light shielding rate according to the temperature environment, and used. It is to provide an optical film that is not easily affected by the environment.

In order to solve the above-mentioned problems, the present inventor has at least one transparent heat insulating layer on the side opposite to the transparent base material of the optical functional layer in the process of examining the cause of the above-mentioned problem. The present inventors have found that an optical film that is not easily affected by the above can be provided, and have reached the present invention.

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

1. An optical film having an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties on a transparent substrate,
An optical film comprising at least one transparent heat insulating layer on the side of the optical functional layer opposite to the transparent substrate.

2. ^2. The optical film according to item 1, wherein the heat resistance of the transparent heat insulating layer is in the range of 1.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ m ² · K / W.

3. The transparent substrate or the transparent heat insulating layer, or the layer between the transparent substrate and the transparent heat insulating layer contains a dye or pigment that absorbs light within a light wavelength range of 400 to 700 nm. Item 3. The optical film according to item 1 or 2, which is characterized.

4. The average optical absorptance of the optical film in the light wavelength range of 400 to 700 nm is in the range of 20 to 80% at 23 ° C., any one of items 1 to 3 The optical film described in 1.

By the above means of the present invention, it is possible to provide an optical film containing vanadium dioxide-containing particles capable of adjusting the near-infrared light shielding rate in accordance with the temperature environment and hardly affected by the use environment.

The expression mechanism / action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The optical film of the present invention has an optical functional layer in which vanadium dioxide-containing particles having thermochromic properties are contained on a transparent substrate, and at least 1 on the opposite side of the optical functional layer from the transparent substrate. It has the transparent heat insulation layer of a layer, It is characterized by the above-mentioned. This makes it possible to provide an optical film that is not easily affected by the use environment.
In the optical film of the present invention, the transparent base material, the optical functional layer, and the transparent heat insulation layer are laminated in this order so as to sandwich the optical function layer, so that the transparent base material and the transparent heat insulation layer serve as a buffer, and are used for the optical function layer. The effect of the environment is suppressed, and it is thought that the chromic property can be switched according to the degree of heating of the optical functional layer by sunlight.

Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic sectional view showing a basic configuration example of the optical film of the present invention Schematic process drawing showing an example of a solvent replacement processing apparatus applicable to the present invention

The optical film of the present invention has an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties on a transparent substrate, and at least one layer on the opposite side of the optical functional layer from the transparent substrate. It has a transparent heat insulation layer. This feature is a technical feature common to the claimed invention.

As an embodiment of the present invention, since the thermal resistance of the transparent heat insulating layer is within the range of 1.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ m ² · K / W because it is not easily affected by the use environment. Preferably there is.

In addition, it is preferable that the transparent substrate or the transparent heat insulating layer, or the layer between the transparent substrate and the transparent heat insulating layer, contains a dye or pigment that absorbs light in the light wavelength range of 400 to 700 nm. Dye or pigment that absorbs light within the light wavelength range of 400-700 nm is heated by absorbing sunlight, and heat is transferred to the optical functional layer containing vanadium dioxide-containing particles. The chromic switching according to the heating degree of sunlight can be performed more effectively without receiving the light.

Further, since the shielding effect and transmission effect of near-infrared light before and after the phase transition of the vanadium dioxide-containing particles can be effectively used, the average light absorption rate of the optical film within the light wavelength range of 400 to 700 nm is 23 ° C. It is preferably in the range of 20 to 85%.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” representing a numerical range is used in the sense that numerical values described before and after the numerical value range are included as a lower limit value and an upper limit value.

<Outline of optical film>
The optical film of the present invention has an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties on a transparent substrate, and at least one layer on the opposite side of the optical functional layer from the transparent substrate. It has the transparent heat insulation layer of this.
In the present invention, “transparent” means that the average light transmittance in the visible light region is 30% or more, preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more. is there.

In the optical film of the present invention, a dye or pigment that absorbs light in the light wavelength range of 400 to 700 nm is formed in the transparent base material or the transparent heat insulating layer, or the layer between the transparent base material and the transparent heat insulating layer. It is a preferable aspect that it is contained.

In the present invention, the dye or pigment that absorbs light in the light wavelength range of 400 to 700 nm is not particularly limited as long as it is a material that absorbs light in the range of 400 to 700 nm, but it is maximum within the range of 350 to 750 nm. A dye or pigment having an absorption wavelength is more preferable because it can efficiently absorb light in the range of 400 to 700 nm.
Here, in the present invention, the “dye” is used as a coloring material to be colored and is dissolved in any solvent such as water or an organic solvent. “Pigment” refers to a pigment that is used as a coloring material to be colored and is in the form of a fine powder of a pigment that does not dissolve in water or an organic solvent.

In the present invention, specific examples of the dye having the maximum absorption wavelength in the light wavelength range of 350 to 750 nm include anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, triarylmethane dyes, and indigo dyes. Etc.

Further, as pigments, compounds classified as pigments in the color index (CI; issued by The Society of Dyersand Colorists), specifically, the following color index (CI) numbers are given. Can be mentioned.

C. I. Pigment red 1, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 4, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 8, C.I. I. Pigment red 9, C.I. I. Pigment red 10, C.I. I. Pigment red 11, C.I. I. Pigment red 12, C.I. I. Pigment red 14, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 17, C.I. I. Pigment red 18, C.I. I. Pigment red 19, C.I. I. Pigment red 21, C.I. I. Pigment red 22, C.I. I. Pigment red 23, C.I. I. Pigment red 30, C.I. I. Pigment red 31, C.I. I. Pigment red 32, C.I. I. Pigment red 37, C.I. I. Pigment red 38, C.I. I. Pigment red 40, C.I. I. Pigment red 41, C.I. I. Pigment red 42, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 49: 1, C.I. I. Pigment red 49: 2, C.I. I. Pigment red 50: 1, C.I. I. Pigment red 52: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 57: 2, C.I. I. Pigment red 58: 2, C.I. I. Pigment red 58: 4, C.I. I. Pigment red 60: 1, C.I. I. Pigment red 63: 1, C.I. I. Pigment red 63: 2, C.I. I. Pigment red 64: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 83, C.I. I. Pigment red 88, C.I. I. Pigment red 90: 1, C.I. I. Pigment red 97, C.I. I. Pigment red 101, C.I. I. Pigment red 102, C.I. I. Pigment red 104, C.I. I. Pigment red 105, C.I. I. Pigment red 106, C.I. I. Pigment red 108, C.I. I. Pigment red 112, C.I. I. Pigment red 113, C.I. I. Pigment red 114, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 151, C.I. I. Pigment red 166, C.I. I. Pigment red 168, C.I. I. Pigment red 170, C.I. I. Pigment red 171, C.I. I. Pigment red 172, C.I. I. Pigment red 174, C.I. I. Pigment red 175, C.I. I. Pigment red 176, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 179, C.I. I. Pigment red 180, C.I. I. Pigment red 185, C.I. I. Pigment red 187, C.I. I. Pigment red 188, C.I. I. Pigment red 190, C.I. I. Pigment red 193, C.I. I. Pigment red 194, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 207, C.I. I. Pigment red 208, C.I. I. Pigment red 209, C.I. I. Pigment red 215, C.I. I. Pigment red 216, C.I. I. Pigment red 220, C.I. I. Pigment red 224, C.I. I. Pigment red 226, C.I. I. Pigment red 242, C.I. I. Pigment red 243, C.I. I. Pigment red 245, C.I. I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment Red 265

C. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Pigment blue 16, C.I. I. Pigment Blue 60

C. I. Pigment green 7, C.I. I. Pigment Green 36

C. I. Pigment brown 23, C.I. I. Pigment Brown 25

C. I. Pigment black 1, C.I. I. Pigment Black 7

Above all, the phthalocyanine C.I. I. Pigment blue 15: 3 (maximum absorption wavelength: 630 nm, 720 nm), C.I. I. Pigment Blue 15: 4 (maximum absorption wavelength: 640 nm, 740 nm), C.I. I. Pigment Blue 16 (maximum absorption wavelength: 620 nm, 690 nm) or the like can be preferably used.

The optical film of the present invention preferably has an average light absorptance within the range of 20 to 80% at 23 ° C. within the light wavelength range of 400 to 700 nm.
The average light absorptance (%) within the light wavelength range of 400 to 700 nm can be determined as follows.

Average light absorptance (%) within the light wavelength range of 400 to 700 nm
= 100-{(Average spectral transmittance in the range of light wavelength 400 to 700 nm)-(Average spectral reflectance in the range of light wavelength 400 to 700 nm)}

The average spectral transmittance and the average spectral reflectance can be measured using a spectrophotometer. In the present invention, the measurement is performed using an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation.
Specifically, the temperature inside the temperature-controlled room is set to 23 ° C. and 55% RH so that the temperature of the optical film as the measurement object is 23 ° C., and the optical film is allowed to stand in the temperature-controlled room for 3 hours to equilibrate. After making the state, the above measurement is performed.

Moreover, it is preferable that the spectral transmittance at an optical wavelength of 1300 nm is 50% or more at 23 ° C., since the shielding effect and the transmission effect before and after the phase transition of the vanadium dioxide-containing particles can be effectively used.
Further, the spectral transmittance at a light wavelength of 550 nm is preferably in the range of 20 to 60% at 23 ° C. from the viewpoint of coloring of the optical film.
In addition, the measurement of these spectral transmittances can also use the same spectrophotometer as the above.

As a means for setting the average light absorptance within the light wavelength range of 400 to 700 nm within the range of 20 to 80%, for example, by adjusting the coating amount of the coating liquid containing the above-mentioned dye or pigment. Can be controlled. The coating amount varies depending on the absorption coefficient of the dye or pigment, but is approximately in the range of 0.01 to 1 g as the coating amount per 1 m ^{2 of the} dye or pigment.

<< Layer structure of optical film >>
The optical film of the present invention is characterized in that an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties is sandwiched between a transparent substrate and at least one transparent heat insulating layer. To do.

In addition, a layer containing a dye or pigment that absorbs light in the light wavelength range of 400 to 700 nm may be provided as a colorant layer between the transparent substrate and the transparent heat insulating layer. Or the pigment may be contained in the optical functional layer together with the vanadium dioxide-containing particles. Moreover, dye or a pigment may be contained in the transparent base material or the transparent heat insulation layer.
From the viewpoint of efficiently transferring solar heat absorbed by the dye or pigment to the vanadium dioxide-containing particles, the dye or pigment is contained in the optical functional layer containing the vanadium dioxide-containing particles or in an adjacent layer in direct contact with the optical functional layer. (See FIGS. 1D to 1H described later.)

As typical configurations of the optical film of the present invention, the following configurations (1) to (9) can be exemplified, but the present invention is not limited thereto.

(1) Transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / adhesive layer (see FIG. 1A)
(2) Clear hard coat layer / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / adhesive layer (see FIG. 1B)
(3) Colorant layer / clear hard coat layer containing dye or pigment / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / adhesive layer (see FIG. 1C)
(4) Clear hard coat layer / colorant layer containing a dye or pigment / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / adhesive layer (see FIG. 1D)
(5) Clear hard coat layer / transparent heat insulating layer / colorant layer containing dye or pigment / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / adhesive layer (see FIG. 1E)
(6) Colorant layer / optical functional layer / transparent substrate / adhesive layer containing clear hard coat layer / transparent heat insulating layer / dye or pigment and vanadium dioxide-containing particles (see FIG. 1F)
(7) Clear hard coat layer / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / colorant layer containing dye or pigment / transparent substrate / adhesive layer (see FIG. 1G)
(8) Clear hard coat layer / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / colorant layer / dye or pigment containing transparent substrate / adhesive layer (see FIG. 1H)
(9) Clear hard coat layer / transparent heat insulating layer / optical functional layer containing vanadium dioxide-containing particles / transparent substrate / colorant layer / adhesive layer containing a dye or pigment (see FIG. 1I)

The adhesive layer can be attached to glass or the like.
Hereinafter, the configuration (5) will be described as an example.

An optical film 1 shown in FIG. 1E absorbs light within a wavelength range of 400 to 700 nm, an optical functional layer 3 containing thermochromic vanadium dioxide-containing particles on one surface of a transparent substrate 2. A colorant layer 4 containing a dye or a pigment, a transparent heat insulating layer 5 and a clear hard coat layer 6 are laminated in this order, and an adhesive layer 7 is laminated on the other surface of the transparent substrate 2.

In the optical functional layer 3, the vanadium dioxide-containing particles are present in a dispersed state in the binder resin.
In the colorant layer 4, a dye or pigment is present in a dispersed state.

The number average particle diameter of the primary particles of the vanadium dioxide-containing particles in the optical functional layer 3 is preferably larger than the number average particle diameter of the primary particles of the pigment particles constituting the pigment.
The number average particle diameter of the vanadium dioxide-containing particles in the optical functional layer 3 can be determined according to the following method.

First, the side surface of the optical functional layer 3 constituting the optical film 1 is trimmed with a microtome to produce an ultrathin section having a cross section as shown in FIG. 1E. Next, the ultrathin section is photographed at 10,000 to 100,000 times using a transmission electron microscope (TEM). The particle size of the primary particles of vanadium dioxide-containing particles existing as single particles in a certain region of the photographed cross section is measured. At this time, the number of vanadium dioxide-containing particles to be measured is preferably in the range of 50 to 100 particles. If the vanadium dioxide-containing particles are not spherical, the projected area of the particles is converted into a circle and the diameter is taken as the particle size. The number average diameter is determined for each diameter of the primary particles. Since the cut-out cross-sectional portion has a variation in particle distribution, such measurement is performed for 10 different cross-sectional regions, the whole number average diameter is obtained, and this is referred to as the number average particle size (nm) in the present invention. To do.

The details of the vanadium dioxide-containing particles according to the present invention will be described later, but the number average particle size of the primary particles is preferably in the range of 5 to 100 nm.
The number average particle diameter of the primary particles of the pigment particles constituting the pigment is preferably in the range of 1 to 100 nm. The number average particle diameter of the pigment particles can be determined, for example, by transmission electron microscope observation (TEM) of an ultrathin slice similarly to the primary particle diameter of the vanadium dioxide-containing particles.

<Optical function layer>
The optical functional layer according to the present invention contains vanadium dioxide-containing particles and a binder resin.

(Vanadium dioxide-containing particles)
Crystalline form of vanadium dioxide-containing particles according to the present invention is not particularly limited, thermochromic (automatic dimming) from the viewpoint of efficient expression, rutile dioxide vanadium-containing particles (VO ₂ containing particles) It is particularly preferable to use it.

Since the rutile vanadium dioxide-containing particles have a monoclinic structure below the phase transition temperature, they are also called M-type. The vanadium dioxide-containing particles according to the present invention may contain other crystal-type vanadium dioxide-containing particles such as A-type or B-type, as long as the object is not impaired.

In the present invention, it is preferable that 95 atomic% or more of the metal component of the vanadium dioxide-containing particles is vanadium, which can exhibit good thermochromic properties. That is, when a metal other than vanadium is doped, it is sufficient if it is doped with less than 5 atomic%. For example, in addition to vanadium, tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir), osmium (Os), ruthenium (Ru) ), Germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F) and phosphorus (P). May be.

The aspect ratio of the vanadium dioxide-containing particles is preferably in the range of 1.0 to 3.0.
The vanadium dioxide-containing particles having such characteristics have a sufficiently small aspect ratio and isotropic shape, and therefore have good dispersibility when added to a solution. In addition, since the single crystal has a sufficiently small particle size, it can exhibit better thermochromic properties than conventional particles.

Further, the concentration of the vanadium dioxide-containing particles in the optical functional layer according to the present invention is not particularly limited, but is generally preferably in the range of 5 to 80% by mass with respect to the total mass of the optical functional layer, more preferably. Is in the range of 5 to 60% by mass, more preferably in the range of 5 to 40% by mass.

(1) Method for Producing Vanadium Dioxide-Containing Particles In general, as a method for producing vanadium dioxide-containing particles, a method of pulverizing a vanadium dioxide sintered body synthesized by a solid phase method, or divanadium pentoxide (V ₂ O ₅ ). Or a pentavalent vanadium compound such as hydrazine or oxalic acid as a raw material together with a pentavalent vanadium compound such as ammonium vanadate (NH ₄ VO ₃ ), or a tetravalent vanadium compound such as vanadyl sulfate as a raw material in the liquid phase An aqueous synthesis method in which particles are grown while synthesizing vanadium dioxide can be mentioned.
The method for producing vanadium dioxide-containing particles according to the present invention is an aqueous system in which particles are grown while synthesizing vanadium dioxide-containing particles in a liquid phase in that the average primary particle size is small and variation in particle size can be suppressed. A synthetic method is preferred.

Furthermore, examples of the aqueous synthesis method include a hydrothermal synthesis method and an aqueous synthesis method using a supercritical state (also referred to as a supercritical hydrothermal synthesis method). Details of the hydrothermal synthesis method will be described later. For the details of the aqueous synthesis method using the supercritical state, for example, the production methods described in paragraphs 0011 and 0015 to 0018 of JP-A-2010-58984 can be referred to.
Among the aqueous synthesis methods, it is preferable to apply the hydrothermal synthesis method.

In addition, as a method for producing vanadium dioxide-containing particles, if necessary, particles such as fine TiO _{2 serving} as the core of particle growth are added as core particles, and vanadium dioxide-containing particles are produced by growing the core particles. You can also

Next, the details of the method for producing vanadium dioxide-containing particles by a hydrothermal synthesis method suitable for the present invention will be described.
Below, the manufacturing process of the vanadium dioxide containing particle | grains by the typical hydrothermal synthesis method is shown.

(Process 1)
A substance (I) containing vanadium (V), hydrazine (N ₂ H ₄ ) or a hydrate thereof (N ₂ H ₄ .nH ₂ O), and water are mixed to prepare a solution (A). This solution may be an aqueous solution in which the substance (I) is dissolved in water, or a suspension in which the substance (I) is dispersed in water.

Examples of the substance (I) include divanadium pentoxide (V ₂ O ₅ ), ammonium vanadate (NH ₄ VO ₃ ), vanadium trichloride (VOCl ₃ ), sodium metavanadate (NaVO ₃ ), and the like. . The substance (I) is not particularly limited as long as it is a compound containing pentavalent vanadium (V). Hydrazine (N ₂ H ₄ ) and its hydrate (N ₂ H ₄ .nH ₂ O) function as a reducing agent for the substance (I) and have a property of being easily dissolved in water.

The solution (A) may further contain a substance (II) containing the element to be added in order to add the element to the finally obtained vanadium dioxide (VO ₂ ) single crystal fine particles. Examples of the element to be added include tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir), osmium (Os), ruthenium ( Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F), or phosphorus (P).

Moreover, this solution (A) may further contain a substance (III) having oxidizing property or reducing property. Examples of the substance (III) include hydrogen peroxide (H ₂ O ₂ ). By adding the oxidizing or reducing substance (III), the pH of the solution can be adjusted, or the substance containing vanadium (V) as the substance (I) can be uniformly dissolved.

(Process 2)
Next, a hydrothermal reaction treatment is performed using the prepared solution (A). Here, “hydrothermal reaction” means a chemical reaction that occurs in hot water (subcritical water) whose temperature and pressure are lower than the critical point of water (374 ° C., 22 MPa). The hydrothermal reaction treatment is performed, for example, in an autoclave apparatus. Single crystal fine particles containing vanadium dioxide (VO ₂ ) are obtained by the hydrothermal reaction treatment.

The conditions of the hydrothermal reaction treatment (for example, the amount of reactants, the treatment temperature, the treatment pressure, the treatment time, etc.) are set as appropriate, but the temperature of the hydrothermal reaction treatment is, for example, within the range of 250 to 350 ° C. Preferably, it is in the range of 250 to 300 ° C, more preferably in the range of 250 to 280 ° C. By reducing the temperature, the particle diameter of the obtained single crystal fine particles can be reduced, but if the particle diameter is excessively small, the crystallinity is lowered.
The hydrothermal reaction treatment time is preferably in the range of 1 hour to 5 days, for example. Increasing the time can control the particle size and the like of the obtained single crystal fine particles, but an excessively long processing time increases the energy consumption.

(Process 3)
If necessary, the surface of the obtained vanadium dioxide-containing particles may be subjected to a coating treatment or a surface modification treatment with a resin. Thereby, the surface of the vanadium dioxide-containing particles can be protected, and surface-modified single crystal fine particles can be obtained. In the present invention, among these, it is preferable that the surface of the vanadium dioxide-containing particles is coated with the same or the same kind of resin as the aqueous binder resin described later.
The “coating” as used in the present invention is a state in which the entire surface of the particle is completely covered with the resin with respect to the vanadium dioxide-containing particles, or a part of the particle surface is covered with the resin. It may be in a state.

Through the above steps 1 to 3, a dispersion containing single crystal fine particles containing thermochromic vanadium dioxide (VO ₂ ) is obtained.

(2) Removal of impurities from vanadium dioxide-containing particle dispersion The dispersion of vanadium dioxide-containing particles prepared by the aqueous synthesis method described above contains impurities such as residues generated during the synthesis process, and has an optical function. It is preferable to remove impurities at the stage of the dispersion liquid in advance because it may cause secondary agglomerated particles when the layer is formed and may cause deterioration in long-term storage of the optical functional layer.

As a method for removing impurities in the vanadium dioxide-containing particle dispersion, conventionally known means for separating foreign substances and impurities can be applied. For example, the vanadium dioxide-containing particle dispersion is subjected to centrifugal separation to contain vanadium dioxide. A method of precipitating particles, removing impurities in the supernatant, adding and dispersing the dispersion medium again, or removing impurities out of the system using an exchange membrane such as an ultrafiltration membrane may be used. From the viewpoint of preventing aggregation of vanadium-containing particles, a method using an ultrafiltration membrane is most preferable.

Examples of the material for the ultrafiltration membrane include cellulose, polyethersulfone, and polytetrafluoroethylene (PTFE). Among these, polyethersulfone and PTFE are preferably used.

(3) Preparation method of solvent dispersion containing vanadium dioxide-containing particles: Solvent replacement treatment In the present invention, when a hydrophobic binder resin is used, an aqueous dispersion containing vanadium dioxide-containing particles is prepared by the aqueous synthesis method described above. After that, it is preferable to prepare a solvent dispersion containing vanadium dioxide-containing particles by a solvent replacement step without passing through the drying process of vanadium dioxide-containing particles as an aqueous dispersion.

The solvent replacement step is composed of a concentration step of concentrating the dispersion liquid containing vanadium dioxide-containing particles, and a solvent dilution step of adding a solvent to the concentrate for dilution, and is composed of a concentration step and a subsequent solvent dilution step. The treatment operation is preferably repeated twice or more to prepare a non-aqueous solvent dispersion containing vanadium dioxide-containing particles.

As the concentration means used in the concentration step of the dispersion containing specific vanadium dioxide-containing particles, an ultrafiltration method is preferable.

Hereinafter, a detailed method of the solvent replacement process will be described.

The solvent applicable in the solvent replacement treatment according to the present invention is an organic solvent, preferably a non-aqueous organic solvent. Finally, it is a step of preparing a solvent dispersion containing vanadium dioxide-containing particles by replacing water, which is a medium constituting the aqueous dispersion containing vanadium dioxide-containing particles, with an organic solvent. By using a solvent dispersion, compatibility with the hydrophobic binder resin forming the optical functional layer is improved, and an optical functional layer with high uniformity can be formed.

The solvent is not particularly limited and can be appropriately selected. For example, ketone solvents such as acetone, dimethyl ketone and methyl ethyl ketone, alcohol solvents such as methanol, ethanol and isopropyl alcohol, and chlorine solvents such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as methyl acetate, ethyl acetate and butyl acetate, glycol ether solvents such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether, dioxane, hexane, octane, diethyl ether, Any material that dissolves the hydrophobic binder resin to be applied at the same time, such as dimethylformamide, can be used.

Specific solvent replacement processing will be described with reference to the drawings.

FIG. 2 is a schematic flow diagram showing an example of a solvent replacement processing apparatus applicable to the present invention.

The solvent replacement processing apparatus 10 shown in FIG. 2 includes a preparation tank 11 for storing the dispersion liquid 12 containing the prepared vanadium dioxide-containing particles, a solvent stock tank 17 storing a solvent 18 for dilution, and a solvent 18. The ultrafiltration unit 15 is used as a concentrating means in the route of the solvent supply line 19 to be added to the adjustment kettle 11, the circulation line 13 for circulating the dispersion 12 stored in the preparation kettle 11 by the circulation pump 14, and the circulation line 13. The discharge port 16 is used to discharge the medium in the dispersion to the outside of the system.

(Process A)
In the preparation kettle 11, the dispersion liquid containing the vanadium dioxide-containing particles prepared by the above method is stored as the dispersion liquid 12 and circulated by the circulation pump 14. It is discharged from the discharge port 16 and concentrated to a predetermined concentration. As a standard of concentration, it concentrates to 20 volume% with respect to the initial volume. It is preferable to avoid excessive concentration beyond this because particle aggregation occurs as the particle density increases. In this concentration operation, it is important not to dry the dispersion 12.

(Process B)
Next, 80% by volume of the initial volume of the solvent 18 is added to the dispersion 12 concentrated to 20% by volume from the solvent stock kettle 17 via the solvent supply line 19 and mixed sufficiently. The following solvent-dispersed dispersion 12 is prepared.

(Process C)
Next, in the same manner as in the above step A, the medium (water + solvent) in the dispersion 12 is discharged out of the system from the discharge port 16 by the ultrafiltration unit 15 while being circulated by the circulation pump 14, and again 20 Concentrate to a volume percent concentration.

(Process D)
Next, in the same manner as in the above step B, 80 mass% of the solvent 18 is added from the solvent stock kettle 17 via the solvent supply line 19 to the concentrated dispersion 12, and the mixture is sufficiently stirred and mixed. A secondary solvent-substituted dispersion 12 is prepared.

(Process E)
Finally, it contains vanadium dioxide-containing particles whose water content is adjusted within the range of 0.1 to 5.0 mass% by repeating the concentration and solvent dilution operations in step A and step B at least twice. A solvent dispersion is prepared. The water content can be determined by measuring, for example, by the Karl Fischer method.

That is, the solvent dispersion containing vanadium dioxide-containing particles according to the present invention can contain water to some extent, and is 30% by mass or less, preferably 10% by mass or less, and particularly preferably 5.0% by mass. % Or less. Moreover, a minimum is 0.01 mass% or more, Preferably it is 0.05 mass% or more, Most preferably, it is 0.1 mass%. Accordingly, the water content is preferably in the range of 0.01 to 30% by mass, and in the range of 0.1 to 5.0% by mass is a particularly preferable embodiment. If the water content in the solvent dispersion is 30% by mass or less, the film forming property of the coexisting hydrophobic binder can be prevented at the time of forming the optical functional layer, and the haze can be reduced to 0.01% by mass. If it is% or more, the change width between the near-infrared light transmittance and the near-infrared light shielding rate at the time of temperature change can be increased to some extent. In particular, when the water content is 5.0% by mass or less, it is possible to further suppress the effect of the vanadium dioxide-containing particles on the oxidation prevention and the film forming property of the coexisting hydrophobic binder, and maintain the haze at a lower level. can do. Moreover, by setting it as 0.1 mass% or more, the change width of the near-infrared-light transmittance at the time of a temperature change and a near-infrared-light shielding rate can further be expanded, and it is preferable conditions.

Examples of the ultrafiltration method used in the above solvent replacement treatment include Research Disclosure No.1. 10208 (1972), no. 13122 (1975) and no. 16351 (1977) and the like can be referred to. Pressure differences and flow rates that are important as operating conditions can be selected with reference to the characteristic curves described in Haruhiko Oya's “Membrane Utilization Technology Handbook”, Koshobo Publishing (1978), p275.

For ultrafiltration membranes, organic membranes, flat plate types, spiral types, cylindrical types, hollow fiber types, hollow fiber types, etc., already incorporated as modules, are available from Asahi Kasei Corporation, Daicel Chemical Co., Ltd. ( Although commercially available from Toray Industries, Inc. and Nitto Denko Corporation, etc., ceramic films such as NGK Co., Ltd. and Noritake Corporation are preferred as the solvent-resistant film.

Specifically, for example, Vivaflow 50 (effective filtration area 50 cm ² , molecular weight cut off 5000) manufactured by Sartorius steady is used as a filtration membrane, and ultrafiltration is performed at a flow rate of 300 ml / min, a hydraulic pressure of 100 kPa, and room temperature (25 ° C.). Examples thereof include an ultrafiltration device having a filtration membrane made of polyethersulfone and having a molecular weight cut off of 300,000 (Pericon 2 cassette manufactured by Nihon Millipore Corporation).

(Binder resin)
Next, the binder resin used for forming the optical functional layer according to the present invention will be described.
The binder resin applicable to the present invention is not particularly limited, but is preferably an aqueous binder resin or a hydrophobic binder resin.
As described above, after preparing an aqueous dispersion containing vanadium dioxide-containing particles by an aqueous synthesis method, a hydrophobic binder resin is used when preparing a solvent dispersion containing vanadium dioxide-containing particles by the above solvent replacement step. It is preferable to use an aqueous binder resin when the solvent substitution step is not performed.

(1) Water-based binder resin The water-based binder resin referred to in the present invention represents a resin material that dissolves 0.5 g or more with respect to 100 g of water at 20 ° C., and more preferably 1.0 g or more. Moreover, after making it melt | dissolve in a hot water, the resin similarly melt | dissolved at 20 degreeC is also defined as an aqueous binder resin as used in the field of this invention.

Examples of the aqueous binder resin useful for the formation of the optical functional layer according to the present invention include gelatins, graft polymers of gelatin and other polymers, proteins such as albumin and casein, celluloses, sodium alginate, and cellulose sulfate. , Dextrin, dextran, saccharide derivatives such as dextran sulfate, naturally-derived materials such as thickening polysaccharides, polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylic Acrylic resins such as nitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid -Acrylate ester co-polymer Styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene acrylic resin, styrene-sodium styrenesulfonate copolymer, styrene- 2-hydroxyethyl acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer Vinyl acetate copolymers such as vinyl naphthalene-maleic acid copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, and salts thereof. Can be mentioned.

Among them, a polymer containing 50 mol% or more of repeating unit components having a hydroxy group, which has a high affinity with vanadium dioxide-containing particles and has a high effect of preventing particle aggregation even during drying of film formation, is preferable. Examples thereof include celluloses, polyvinyl alcohols, and acrylic resins having a hydroxy group. Among them, polyvinyl alcohols and celluloses can be most preferably used.

Hereinafter, typical aqueous binder resins useful for forming the optical functional layer according to the present invention will be described.

(1.1) Polyvinyl alcohols As polyvinyl alcohols preferably used in the present invention, ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate can be used.
In addition to ordinary polyvinyl alcohol, modified polyvinyl alcohols such as polyvinyl alcohols whose ends are cationically modified and anionic modified polyvinyl alcohols having an anionic group are also included.

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

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

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

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

As the polyvinyl alcohol used in the present invention, a synthetic product or a commercially available product may be used. Examples of commercially available products used as polyvinyl alcohol include, for example, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, PVA-203, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235 (above, manufactured by Kuraray Co., Ltd.), JC-25, JC-33, JF-03, JF-04, JF-05, JP- 03, JP-04, JP-05, JP-45 (above, manufactured by Nippon Vinegar Poval Co., Ltd.) and the like.

(1.2) Cellulose As the cellulose that can be used for forming the optical functional layer according to the present invention, a water-soluble cellulose derivative is preferable, for example, carboxymethyl cellulose (cellulose carboxymethyl ether), methyl cellulose, hydroxymethyl cellulose, Examples thereof include water-soluble cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose, carboxymethyl cellulose (cellulose carboxymethyl ether) and carboxyethyl cellulose, which are carboxylic acid group-containing celluloses. Other examples include cellulose derivatives such as nitrocellulose, cellulose acetate propionate, cellulose acetate, and cellulose sulfate.

In the present invention, it is one of the preferred embodiments that the aqueous binder resin is a polymer containing 50 mol% or more of repeating units having a hydroxy group. In the case of celluloses, the repeating unit component is originally composed of three hydroxy units. And some of these three hydroxy groups are substituted. The content of 50 mol% or more of repeating unit components having a hydroxy group means that 50 mol% or more of the repeating unit component having a hydroxy group in this substituent or the repeating unit component in which one or more unsubstituted hydroxy groups remain is contained. Represents that.

(1.3) Gelatin As the gelatin applicable to the present invention, various gelatins conventionally used widely in the field of silver halide photographic light-sensitive materials can be applied, such as acid-processed gelatin and alkali-processed gelatin. In addition, enzyme-treated gelatin and gelatin derivatives that undergo enzyme treatment in the gelatin production process, that is, groups having amino groups, imino groups, hydroxy groups, carboxy groups as functional groups in the molecule, and groups obtained by reaction with them. It may be modified by treating with a reagent. Well-known methods for producing gelatin are well known. H. James: The Theory of Photographic Process 4th. ed. Reference can be made to descriptions such as 1977 (Maccillan), p. 55, Science Photo Handbook (above), p. 72-75 (Maruzen), Fundamental of Photographic Engineering-Silver Salt Photo Hen, pages 119-124 (Corona). Also, Research Disclosure Magazine Vol. 176, No. And gelatin described on page IX of 17643 (December 1978).

Further, when gelatin is used as the aqueous binder resin, a gelatin hardener can be added as necessary. As the hardener that can be used, known compounds that are used as hardeners for ordinary photographic emulsion layers can be used. For example, vinyl sulfone compounds, urea-formalin condensates, melanin-formalin condensates, epoxy compounds And organic hardeners such as aziridine compounds, active olefins and isocyanate compounds, and inorganic polyvalent metal salts such as chromium, aluminum and zirconium.

(1.4) Thickening polysaccharide There is no restriction | limiting in particular as thickening polysaccharide which can be used by this invention, For example, generally known natural simple polysaccharide, natural complex polysaccharide, synthetic simple polysaccharide, and Synthetic complex polysaccharides can be mentioned. For details of these polysaccharides, refer to “Biochemical Encyclopedia (2nd edition), Tokyo Kagaku Dojin Publishing”, “Food Industry”, Vol. 31 (1988), p. 21. be able to.

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

Examples of the thickening polysaccharide applicable to the present invention include galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum, guaran, etc.), xyloglucan (eg, tamarind gum, etc.), Glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabinogalactoglycan (eg, soybean-derived glycan, microorganism-derived glycan, etc.), Red algae such as glucuronoglycan (eg gellan gum), glycosaminoglycan (eg hyaluronic acid, keratan sulfate etc.), alginic acid and alginates, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan Derived from From the viewpoint of not reducing the dispersion stability of the vanadium dioxide-containing particles coexisting in the coating solution, natural polymer polysaccharides and the like are preferable. Preferably, the structural unit does not have a carboxylic acid group or a sulfonic acid group. . Examples of such polysaccharides include pentoses such as L-arabitose, D-ribose, 2-deoxyribose and D-xylose, and hexoses such as D-glucose, D-fructose, D-mannose and D-galactose only. It is preferable that it is a polysaccharide. Specifically, tamarind seed gum known as xyloglucan whose main chain is glucose and side chain is glucose, guar gum known as galactomannan whose main chain is mannose and side chain is glucose, cationized guar gum, Hydroxypropyl guar gum, locust bean gum, tara gum, and arabinogalactan whose main chain is galactose and whose side chain is arabinose can be preferably used. In the present invention, tamarind, guar gum, cationized guar gum, and hydroxypropyl guar gum are particularly preferable.

(1.5) Polymers having reactive functional groups Examples of aqueous binder resins applicable to the present invention include polymers having reactive functional groups, such as polyvinylpyrrolidones, polyacrylic acid, acrylic acid- Acrylic resins such as acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene -Methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, etc. Styrene acrylic acid resin, styrene-sodium styrene sulfonate copolymer Styrene-2-hydroxyethyl acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinylnaphthalene-acrylic acid Copolymers, vinyl naphthalene-maleic acid copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-based copolymers such as vinyl acetate-acrylic acid copolymers, and the like Of the salt. Among these, particularly preferred examples include polyvinylpyrrolidones and copolymers containing the same.

For details of the acrylic polymer having a hydroxy group, the contents described in paragraphs 0049 to 0052 of International Publication No. 2011/148931 can be referred to.

(2) Hydrophobic binder resin In the present invention, the hydrophobic binder resin refers to a resin having a dissolution amount of less than 1.0 g at a liquid temperature of 25 ° C. with respect to 100 g of water. The amount of the resin is less than 0.5 g, particularly preferably the resin having a dissolution amount of less than 0.25 g.

The hydrophobic binder resin is preferably a resin obtained by polymerizing in the curing process using a hydrophobic polymer or a monomer of the hydrophobic binder resin.

Examples of the hydrophobic polymer applicable to the present invention include polyethylene, polypropylene, ethylene-propylene copolymers, olefin polymers such as poly (4-methyl-1-pentene), acrylate copolymers, chlorides, and the like. Halogen-containing polymers such as vinyl and chlorinated vinyl resins, styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer, polyethylene terephthalate, poly Polyesters such as butylene terephthalate and polyethylene naphthalate, polyamides such as nylon 6, nylon 66 and nylon 610, polyacetal, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyether ABS resin (acrylonitrile-butadiene-styrene resin), ASA resin (acrylonitrile-styrene-acrylate resin), cellulose blended with rutheketone, polysulfone, polyethersulfone, polyoxybenzylene, polyamideimide, polybutadiene rubber, acrylic rubber Resin, butyral resin, and the like.

In addition, as a hydrophobic binder resin applicable to the present invention, a resin that is polymerized in a curing process using a monomer of a hydrophobic binder resin can be exemplified, and typical hydrophobic binder resin materials include: A compound that is cured by irradiation with active energy rays, specifically a radical polymerizable compound that is cured by a polymerization reaction with radical active species, and a cationic polymerizable compound that is cured by a cationic polymerization reaction with cationic active species. it can.

Examples of the radical polymerizable compound include a compound having an ethylenically unsaturated bond capable of radical polymerization. Examples of the compound having an ethylenically unsaturated bond capable of radical polymerization include acrylic acid, methacrylic acid, itaconic acid, and crotonic acid. , Unsaturated carboxylic acids such as isocrotonic acid and maleic acid and their salts, esters, urethanes, amides and anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, unsaturated urethanes, etc. These radically polymerizable compounds are mentioned. Specifically, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol Diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate, pentaerythritol Tetraacrylate, dipentaery Acrylic acid derivatives such as lithol tetraacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, N-methylolacrylamide, diacetoneacrylamide, epoxy acrylate, methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate , Lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylol Methacryl derivatives such as tan trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, and other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate Is mentioned.

As the cationic polymerizable compound, various known cationic polymerizable monomers can be used. For example, JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like exemplified in JP-A-2001-220526.

It is preferable to contain a photopolymerization initiator together with the above compound. As photopolymerization initiators, all known photopolymerization initiators listed in “Application and Market of UV / EB Curing Technology” (CMC Publishing Co., Ltd., edited by Yoneho Tabata / edited by Radtech Research Association) should be used. Can do.

In the present invention, after applying a coating solution for forming an optical functional layer containing each constituent material and a solvent dispersion containing vanadium dioxide-containing particles, for example, on a transparent substrate, thereafter, ultraviolet rays, electron beams, etc. Irradiate active energy rays. The composition which comprises the optical function layer thin film formed by this hardens | cures rapidly.

As a light source of active energy rays, when irradiating ultraviolet rays, for example, ultraviolet LED, ultraviolet laser, mercury arc lamp, xenon arc lamp, low pressure mercury lamp, fluorescent lamp, carbon arc lamp, tungsten-halogen copying lamp and sunlight are used. Can be used. In the case of curing with an electron beam, it is usually cured with an electron beam having an energy of 300 eV or less, but it can also be cured instantaneously with an irradiation dose of 1 to 5 Mrad.

(Other additives for optical functional layers)
Various additives that can be applied to the optical functional layer according to the present invention as long as the effects of the present invention are not impaired are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, JP-A-62-261476, JP-A-57-74192, JP-A-57- No. 878989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, JP-A-3-13376, etc. Or nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, JP-A-4-219266 Fluorescent brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents, and polyethylene Lubricants such as glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, lubricants, infrared absorbers And various known additives such as dyes and pigments.

(Method for forming optical functional layer)
Although there is no restriction | limiting in particular as a formation method of the optical function layer based on this invention, The case where a water-based binder resin is used differs from the case where a hydrophobic binder resin is used.

In the case of using an aqueous binder resin, after preparing vanadium dioxide-containing particles by an aqueous synthesis method, a state of a dispersion in which vanadium dioxide-containing particles exist without being associated with each other without passing through a drying step. Then, by mixing an aqueous binder resin solution prepared by dissolving an aqueous binder resin in an aqueous solvent, an aqueous optical functional layer forming coating solution is prepared, and this optical functional layer forming coating solution is prepared by a wet coating method. A method of forming an optical functional layer by applying and drying on a transparent substrate is preferred.

When a hydrophobic binder resin is used, vanadium dioxide-containing particles are prepared in the same manner as when an aqueous binder resin is used. After that, without passing through a drying step, a solvent dispersion containing vanadium dioxide-containing particles is prepared by a solvent substitution step, and then mixed and dissolved with a hydrophobic binder resin, etc. for forming a non-aqueous optical functional layer A method is preferred in which a coating solution is prepared, and this non-aqueous coating solution for forming an optical functional layer is applied and dried on a transparent substrate by a wet coating method to form an optical functional layer.

The wet coating method used for forming the optical functional layer is not particularly limited, and for example, a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a slide curtain coating method, or US Pat. No. 2,761,419. Examples thereof include a slide hopper coating method and an extrusion coating method described in the specification, US Pat. No. 2,761791.

<Transparent insulation layer>
The transparent heat-insulating layer according to the present invention is not particularly limited as long as it is transparent and has an effect of suppressing heat transfer, for example, a transparent polymer layer, a transparent porous layer, a layer containing hollow particles or porous particles, etc. Can be mentioned.

In order to suppress heat transfer, the thermal resistance (R) of the transparent heat insulating layer is preferably in the range of 1.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ m ² · K / W. More preferably, it is in the range of 5 × 10 ⁻⁴ to 1.5 × 10 ⁻³ . If the thermal resistance of the transparent heat insulating layer (R) is ^{1.0 × 10 -4 m 2 · K} / W or more, a large effect of preventing the influence of the external environment such as air conditioning, 2.5 × 10 ^{- If it is 3} m < ² > * K / W or less, when the sunlight which hits the heated optical film will become weak, it can suppress that the temperature of an optical film falls quickly and continues shielding of near-infrared light.
The thermal resistance (R) (m ² · K / W) can be obtained by thickness (d) (m) ÷ material thermal conductivity (λ) (W / (m · K)).

The thickness of the transparent heat insulating layer may be appropriately set according to the constituent material (thermal conductivity (λ)) of the transparent heat insulating layer.

(Transparent polymer layer)
An example of the transparent polymer layer is a transparent resin film. Examples of transparent resin films include polyolefin films (eg, cycloolefin, polyethylene, polypropylene, etc.), polyester films (eg, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, polycarbonate films, triacetylcellulose films, acrylic films. (Polymethylmethacrylate etc.) etc. can be used, Preferably it is a polyethylene terephthalate film.

(Transparent porous layer)
As a method for forming the transparent porous layer, for example, a method for forming a porous layer using a sol-gel method can be used. For example, in the method for producing a porous silica material, generally, alkoxysilane is hydrolyzed, and the generated silica sol is polycondensed to form a wet gel, which is dried to obtain a porous silica material.

(Hollow particle-containing layer)
As the hollow particle-containing layer, for example, a layer in which hollow particles described in JP-T-2000-500113, JP-A-2005-263550, JP-A-2012-144394, etc. are contained in a transparent resin is used. Can do. As a method for forming a layer by incorporating hollow particles in a transparent resin, the layer can be similarly produced by using hollow particles instead of vanadium dioxide-containing particles in the optical functional layer described above.

(Porous particle containing layer)
As the porous particle-containing layer, for example, it is possible to use a layer in which transparent resin contains particles obtained by atomizing methyl silicate monomer obtained by air drying by atmospheric pressure drying or critical drying. For example, JP 2013-100406 A can be referred to.

<Transparent substrate>
The transparent substrate applicable to the present invention is not particularly limited as long as it is transparent, and examples thereof include glass, quartz, and a transparent resin film. However, it is possible to impart flexibility and suitability for production (manufacturing process suitability). From the viewpoint, a transparent resin film is preferable.

The thermal resistance (R) of the transparent substrate is preferably in the range of 1.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ m ² · K / W. When the thermal resistance (R) of the transparent substrate is 1.0 × 10 ⁻⁴ m ² · K / W or more, the effect of preventing the influence of an external environment such as an air conditioner is great. In addition, because of the large heat capacity of glass compared to the optical film, even if the temperature of the outside air drops and there is no need to shield near-infrared light, it is possible to shield near-infrared light by the influence of the residual heat of the glass heated by the sun. The condition continued. An optical film that can suppress the influence of the heat of glass because the thermal resistance (R) of the transparent substrate is 2.5 × 10 ⁻³ m ² · K / W or less, and is less affected by the external environment can do.

The thickness of the transparent substrate according to the present invention is preferably in the range of 30 to 200 μm, more preferably in the range of 30 to 100 μm, and still more preferably in the range of 35 to 70 μm. If the thickness of the transparent substrate is 30 μm or more, wrinkles and the like are less likely to occur during handling, and if the thickness is 200 μm or less, the followability to the curved glass surface when bonded to the glass substrate is improved.

The transparent substrate according to the present invention is preferably a biaxially oriented polyester film, but an unstretched or at least one stretched polyester film can also be used. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression. In particular, when the laminated glass provided with the optical film of the present invention is used as glass for automobiles, a stretched film is more preferable.

The transparent substrate according to the present invention has a thermal shrinkage within a range of 0.1 to 3.0% at a temperature of 150 ° C. from the viewpoint of preventing generation of wrinkles of the optical film and cracking of the optical functional layer. Is preferable, more preferably in the range of 1.5 to 3.0%, still more preferably 1.9 to 2.7%.

The transparent substrate applicable to the optical film of the present invention is not particularly limited as long as it is transparent, but various resin films are preferably used. For example, polyolefin films (for example, cycloolefin, polyethylene, polypropylene) Etc.), polyester films (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, triacetyl cellulose films and the like can be used, and cycloolefin films, polyester films, and triacetyl cellulose films are preferable.

The transparent resin film is preferably coated with an undercoat layer coating solution inline on one or both sides during the film formation process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating.

<Colorant layer>
In the present invention, among the layer configurations of the optical film, as in the layer configuration of (5) or (7) above (see FIG. 1E or FIG. 1G), the dye or pigment according to the present invention is added to vanadium dioxide-containing particles. You may make it contain in a colorant layer as an adjacent layer which contacts the optical function layer in which was contained. As the binder of the colorant layer, for example, the aforementioned hydrophobic binder resin can be used.

<Clear hard coat layer>
The clear hard coat layer (CHC layer) according to the present invention is a layer provided on the opposite side of the transparent heat insulating layer from the optical functional layer.
In the present invention, a dye or pigment may be included in the clear hard coat layer as in the layer configuration of (3) above (see FIG. 1C).

As the clear hard coat material of the clear hard coat layer, an inorganic material typified by polysiloxane, an active energy ray curable resin, or the like can be used.
Inorganic materials need to be moisture-cured (from room temperature to warming). From the viewpoint of curing temperature, curing time, and cost, it is preferable to use an active energy ray-curable resin in the present invention.

The active energy ray resin refers to a resin that is cured through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays and electron beams. As the active energy ray curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active energy ray curable resin layer is cured by irradiation with an active ray such as an ultraviolet ray or an electron beam. It is formed. Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.

As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, UV curable acrylate resins are preferred. UV curable acrylic urethane resins generally contain 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as methacrylates) in addition to products obtained by reacting polyester polyols with isocyanate monomers or prepolymers. Only acrylates are indicated as such), and can be easily obtained by reacting an acrylate monomer having a hydroxy group such as 2-hydroxypropyl acrylate.

For example, a mixture of 100 parts by mass of Unidic 17-806 (manufactured by DIC Corporation) and 1 part by mass of Coronate L (manufactured by Tosoh Corporation) described in JP-A-59-151110 is preferably used. .
An ultraviolet curable polyester acrylate resin can be easily obtained by reacting a monomer such as 2-hydroxyethyl acrylate, glycidyl acrylate, or acrylic acid with a hydroxyl group or carboxy group at the end of the polyester (see, for example, JP (See Sho 59-151112).
The ultraviolet curable epoxy acrylate resin is obtained by reacting a terminal hydroxyl group of an epoxy resin with a monomer such as acrylic acid, acrylic acid chloride, or glycidyl acrylate.
UV curable polyol acrylate resins include ethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipenta Examples include erythritol pentaacrylate, dipentaerythritol hexaacrylate, and alkyl-modified dipentaerythritol pentaacrylate.

<Adhesive layer>
An adhesion layer is a layer for making the optical film of this invention adhere to another base material. When using the optical film of this invention as a window film, it is a layer for making it adhere to a window glass.
In the present invention, among the layer configuration of the optical film, a dye or pigment may be contained in the adhesive layer as in the layer configuration of (9) above (see FIG. 1I).

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer is selected from rubber-based, acrylic-based, silicone-based and urethane-based pressure-sensitive adhesives. Since there is no yellowing over time, acrylic and silicone are preferred, and acrylic is most preferred because a general-purpose release sheet can be used.

Further, the thickness of the adhesive layer is preferably in the range of 5 to 30 μm. If it is 5 μm or more, the adhesiveness is stable, and if it is 30 μm or less, the adhesive does not protrude from the side of the film and is easy to handle.

As for the type of separator (release sheet) to be bonded to the adhesive layer, a substrate such as polyester, polyethylene, polypropylene, paper, etc., which is coated with silicone coat, polyalkylene coat or fluororesin can be used. However, dimensional stability and smoothness can be used. From the viewpoint of peel stability, a polyester film coated with silicone is particularly preferred.
The thickness of the separator is preferably in the range of 10 to 100 μm, more preferably in the range of 20 to 60 μm. If it is 10 μm or more, the film is not wrinkled due to heat during coating and drying, and it is preferably 100 μm or less from the viewpoint of economy.

<< Use of optical film >>
As an application of the optical film of the present invention, it can be configured to be pasted on glass, and the glass on which this film is bonded can be used for automobiles, railway vehicles, aircraft, ships, buildings, and the like. The glass bonded together can be used for other purposes. The glass bonded with the film is preferably used for construction or for vehicles. The glass bonded with the film can be used for a windshield, side glass, rear glass or roof glass of an automobile.

Examples of the glass member include inorganic glass and organic glass (resin glazing).
Examples of the inorganic glass include colored glass such as float plate glass, heat ray absorbing plate glass, polished plate glass, mold plate glass, meshed plate glass, wire-containing plate glass, and green glass.
Organic glass is a synthetic resin glass that can be substituted for inorganic glass. Examples of organic glass (resin glazing) include polycarbonate plates and poly (meth) acrylic resin plates. Examples of the poly (meth) acrylic resin plate include a polymethyl (meth) acrylate plate.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

<< Preparation of dispersion of vanadium dioxide-containing particles >>
<Preparation of dispersion 1 of vanadium dioxide-containing particles>
1 g of vanadate ammonium (V) (NH ₄ VO ₃ , Wako Pure Chemicals, special grade) is mixed with 25 g of pure water, and hydrazine monohydrate (N ₂ H ₄ · H ₂ O, Wako Pure Chemical Industries, special grade) is mixed. ) Was slowly added dropwise.
The prepared reaction solution is placed in a high-pressure reaction decomposition vessel stationary HU 50 ml set (pressure-resistant stainless steel outer tube, PTFE sample vessel HUTc-50: manufactured by Sanai Kagaku Co., Ltd.), 100 ° C. for 2 hours, and subsequently 275 ° C. The hydrothermal reaction was carried out for 24 hours.
After the reaction, the resulting product is washed using ultrafiltration, the concentration of the finished vanadium dioxide-containing particles is adjusted to 3.0% by mass, and further 15 masses per 100 parts by mass of the vanadium dioxide-containing particles. Polyvinylpyrrolidone (PVP, manufactured by Nippon Shokubai Co., Ltd., K-30) was added at a ratio of 1 part, and dispersed with a super apex mill manufactured by Kotobukisha using zirconia beads having a particle size of 30 μm. Was prepared.

<Preparation of dispersion 2 of vanadium dioxide-containing particles>
3.5 wt% of hydrogen peroxide solution (Wako Pure Chemical Industries, Ltd.) aqueous solution was mixed with 1g of pure water 30g, vanadium pentoxide _{(V) (V} 2 _{O 5,} special grade, Wako Pure Chemical) to 1g In addition, after stirring at 30 ° C. for 4 hours, 0.15 g of a 5 mass% aqueous solution of hydrazine monohydrate (N ₂ H ₄ .H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., special grade) was slowly added dropwise and stirred for 1 hour. went.
Thereafter, a solution obtained by diluting ammonia water (Wako Pure Chemicals, 30 mass% aqueous solution) to 4 mass% was added to adjust pH (25 ° C. conversion) to 5.0. The added ammonia water was 0.2 g.
The prepared reaction solution is placed in a high-pressure reaction decomposition container stationary HU 50 ml set (pressure-resistant stainless steel outer tube, PTFE sample container HUTc-50: manufactured by Sanai Kagaku Co., Ltd.) and subjected to a hydrothermal reaction at 275 ° C. for 48 hours. went. PH (25 degreeC conversion) after hydrothermal reaction of the reaction liquid was 8.7.
After the reaction, the resulting product is washed using ultrafiltration, the concentration of the finished vanadium dioxide-containing particles is adjusted to 3.0% by mass, and further 15 masses per 100 parts by mass of the vanadium dioxide-containing particles. Polyvinylpyrrolidone (PVP, manufactured by Nippon Shokubai Co., Ltd., K-30) was added at a ratio of 1 part, and dispersed with a super apex mill manufactured by Kotobukisha using 30 μm zirconia beads to prepare a dispersion 2 of vanadium dioxide-containing particles. did.

<Preparation of dispersion 3 of vanadium dioxide-containing particles>
1 g of vanadate ammonium (V) (NH ₄ VO ₃ , Wako Pure Chemicals, special grade) is mixed with 25 g of pure water, and hydrazine monohydrate (N ₂ H ₄ · H ₂ O, Wako Pure Chemical Industries, special grade) is mixed. ) Was slowly added dropwise.
The prepared reaction solution is placed in a high-pressure reaction decomposition vessel stationary HU 50 ml set (pressure-resistant stainless steel outer tube, PTFE sample vessel HUTc-50: manufactured by Sanai Kagaku Co., Ltd.), 100 ° C. for 2 hours, and subsequently 275 ° C. The hydrothermal reaction was carried out for 24 hours.
After the reaction, an ultrafiltration apparatus having a filtration membrane made of polyethersulfone and having a molecular weight cut off of 300,000 (Pericon 2 manufactured by Nihon Millipore Corporation) with the reaction solution kept at 20 ° C. while circulating in the system. Concentration operation was performed using the solvent displacement treatment apparatus shown in FIG. 2 equipped with a cassette), and when the initial volume was 100% by volume, after concentration to 20% by volume, ethyl alcohol was added and 100% by volume. It was. Next, the dispersion was concentrated again to 20% by volume, then methyl ethyl ketone was added as a solvent to make 100% by volume, and the solvent was subjected to two solvent substitution treatments. The solvent-based vanadium dioxide-containing particles having a particle concentration of 3% by mass A dispersion 3 was prepared.

<< Production of optical film >>
<Preparation of optical film 101>
(Formation of optical functional layer)
On a transparent base material of a polyethylene terephthalate (PET) film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, using an extrusion coater, the coating solution 1 for forming an optical functional layer having the following composition was dried. Is applied by wet coating under a condition of 1.5 μm, and then dried by blowing hot air at 50 ° C. for 2 minutes to form an optical functional layer containing vanadium dioxide-containing particles. Produced.

[Optical functional layer forming coating solution 1]
Dispersion 1 of vanadium dioxide-containing particles 1 10 parts by weight Aqueous solution of 4% by weight of hydroxypropyl methylcellulose (Metroose 60SH-50, manufactured by Shin-Etsu Chemical Co., Ltd.) 75 parts by weight 5% by weight of an aqueous surfactant solution (Triton X-100, Sigma-Aldrich) 2 parts by mass pure water 13 parts by mass

(Formation of clear hard coat layer)
Directly adjacent on the optical functional layer, a clear hard coat layer forming coating solution 1 having the following composition is wet coated by adjusting the coating amount so that the dry film thickness becomes 2 μm using an extrusion coater. Dry at 1 ° C. for 1 minute. Next, using an ultraviolet lamp, the coating film was cured by irradiating ultraviolet rays under the conditions of an illuminance of 100 mW / cm ² , an irradiation amount of 0.2 J / cm ² , and an oxygen concentration of 200 ppm to form a clear hard coat layer. .

[Clear hard coat layer coating solution 1]
Aronix (registered trademark) M-305 (3, 4-functional acrylate, trifunctional component 60 mass%, manufactured by Toagosei Co., Ltd.) 196 parts by mass EBECRYL (registered trademark) 350 (bifunctional silicon acrylate, manufactured by Daicel Ornex Corp.) MIBK (methyl isobutyl ketone) diluted solution (1% by mass) 18 parts by mass Hexoate cobalt 8% (metal soap, manufactured by Toei Chemical Co., Ltd.) 3 parts by mass Irgacure (registered trademark) 184 (photopolymerization initiator, BASF Corporation) (Manufactured) 13 parts by mass MegaFac (registered trademark) F-552 (surfactant, manufactured by DIC Corporation) MIBK (methyl isobutyl ketone) diluent (1% by mass) 9 parts by mass MIBK (methyl isobutyl ketone) 446 parts by mass

(Formation of adhesive layer)
An adhesive layer forming coating solution 1 having the following composition is applied on the surface opposite to the optical functional layer across the PET film so that the dry film thickness is 10 μm, and dried at 90 ° C. for 1 minute. The optical film 101 was produced by forming.
A release film (MRF # 25, manufactured by Mitsubishi Resin Co., Ltd.) was bonded to the outermost surface on the adhesive layer side to protect the surface.

[Coating layer forming coating solution 1]
N-2147 (acrylic adhesive, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
100 parts by mass Tinuvin (registered trademark) 477 (ultraviolet absorber, manufactured by BASF Japan Ltd.) 2.1 parts by mass Coronate (registered trademark) HL (curing agent, manufactured by Tosoh Corporation) 5 parts by mass MIBK (methyl isobutyl ketone) 300 Parts by mass

<Preparation of optical film 102>
It was produced in the same manner as the optical film 101 until the optical functional layer was formed on the PET film.

(Preparation of transparent insulation layer PET1)
After commercially available polyethylene terephthalate (PET, intrinsic viscosity 0.65) was vacuum-dried at 150 ° C. for 8 hours, it was melt-extruded with a T-die at 280 ° C. using an extruder, and adhered to a cooling drum while applying electrostatic force, Cooled and solidified to obtain an unstretched sheet. This unstretched sheet was stretched 3.5 times in the longitudinal direction at 90 ° C. using a roll type longitudinal stretching machine. The obtained uniaxially stretched film was stretched by 50% of the total transverse stretching ratio in the first stretching zone 100 ° C. using a tenter-type transverse stretching machine, and further in the second stretching zone 120 ° C., the total transverse stretching ratio 3.6 times. It extended | stretched so that it might become. Next, heat treatment was performed at 100 ° C. for 2 seconds, heat setting was further performed at the first heat setting zone 170 ° C. for 5 seconds, and heat setting was performed at the second heat setting zone 210 ° C. for 15 seconds. Subsequently, it was gradually cooled to room temperature (25 ° C.) over 30 seconds while being subjected to a 5% relaxation treatment in the lateral direction to obtain PET 1 for a transparent heat insulation layer having a thickness of 12 μm. The thermal resistance of the transparent insulating layer PET1 was 0.86 × 10 ⁻⁴ m ² · K / W.

Each surface of PET 1 for transparent heat insulation layer is subjected to a corona discharge treatment of 12 W · min / m ² , and an easy-adhesion layer-forming coating solution 1 having the following composition is applied to a dry film thickness of 0.4 μm. 12 W · min / m ² of corona discharge treatment, and the easy-adhesion layer-forming coating solution 2 having the following composition was applied so as to have a dry film thickness of 0.06 μm. did.

[Coating liquid 1 for easy adhesion layer formation]
Copolymer latex solution (30% solid content) of 30% by weight of butyl acrylate, 20% by weight of t-butyl acrylate, 25% by weight of styrene and 25% by weight of 2-hydroxyethyl acrylate 50 g
Compound (UL-1) 0.2g
Hexamethylene-1,6-bis (ethyleneurea) 0.05g
1000ml of pure water

[Coating liquid 2 for easy adhesion layer formation]
10g gelatin
Compound (UL-1) 0.2g
Compound (UL-2) 0.2g
Hardener (UL-3) 1g
1000ml of pure water

(Formation of clear hard coat layer)
The clear hard coat layer-forming coating solution 1 was applied to one surface of the transparent heat-insulating layer-coated PET 1 with the easy adhesion layer applied in the same manner as the optical film 101.

The adhesive layer forming coating solution 1 having the following composition is applied on the surface opposite to the surface coated with the clear hard coat layer forming coating solution 1 so that the dry film thickness is 10 μm. It dried for minutes and bonded together with the optical function layer of the PET film prepared previously.

[Adhesive layer forming coating solution 1]
N-2147 (acrylic adhesive, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
100 parts by mass Coronate (registered trademark) HL (curing agent, manufactured by Tosoh Corporation) 5 parts by mass MIBK (methyl isobutyl ketone) 300 parts by mass

(Formation of adhesive layer)
Further, the adhesive layer forming coating solution 1 is applied on the surface opposite to the optical functional layer across the PET film so that the dry film thickness is 10 μm, and dried at 90 ° C. for 1 minute to form the adhesive layer. The optical film 102 was produced by forming.
A release film (MRF # 25, manufactured by Mitsubishi Resin Co., Ltd.) was bonded to the outermost surface on the adhesive layer side to protect the surface.

<Preparation of optical films 103-111>
Optical films 103 to 111 were produced in the same manner as in the production of the optical film 102 except that the transparent heat insulating layer PET1 was replaced with the following transparent heat insulating layer PET.

The optical film 103: transparent heat insulating layer PET 2 (thickness 15 [mu] m, the thermal resistance ^{1.07 × 10 -4 m 2 · K} / W)
Optical film 104: PET3 for transparent heat insulation layer (thickness 25 μm, thermal resistance 1.79 × 10 ⁻⁴ m ² · K / W)
Optical film 105: PET4 for transparent heat insulation layer (thickness 50 μm, thermal resistance 3.57 × 10 ⁻⁴ m ² · K / W)
Optical film 106: PET5 for transparent heat insulating layer (thickness 100 μm, thermal resistance 7.14 × 10 ⁻⁴ m ² · K / W)
Optical film 107: PET6 for transparent heat insulating layer (thickness 150 μm, thermal resistance 1.07 × 10 ⁻³ m ² · K / W)
Optical film 108: PET7 for transparent heat insulation layer (thickness 200 μm, thermal resistance 1.43 × 10 ⁻³ m ² · K / W)
Optical film 109: PET8 for transparent heat insulation layer (thickness 250 μm, thermal resistance 1.79 × 10 ⁻³ m ² · K / W)
Optical film 110: PET9 for transparent heat insulation layer (thickness 350 μm, thermal resistance 2.50 × 10 ⁻³ m ² · K / W)
Optical film 111: PET10 for transparent heat insulation layer (thickness 400 μm, thermal resistance 2.86 × 10 ⁻³ m ² · K / W)

<Preparation of optical films 112-121>
In the production of the optical films 102 to 111, 15 parts by mass of HTP Blue # B012M manufactured by Gokoku Dye Co., Ltd. An optical film was prepared in the same manner except that the liquid mixed at a ratio of 25 parts by mass was added by adjusting the addition amount so that the average optical absorptance of the optical film in the light wavelength range of 400 to 700 nm was 55%. 112 to 121 were produced.

<Preparation of optical films 122 to 124>
In the production of the optical film 115, the addition amount of the pigment that absorbs light within the light wavelength range of 400 to 700 nm is the average light absorption rate of the optical film within the light wavelength range of 400 to 700 nm as shown in Table 1. Optical films 122 to 124 were produced in the same manner except that the adjustment was performed.

<Preparation of optical film 125>
An optical film 125 was produced in the same manner as in the production of the optical film 115 except that the dispersion 2 of vanadium dioxide-containing particles was used instead of the dispersion 1 of vanadium dioxide-containing particles.

<Preparation of Optical Film 126>
In the production of the optical film 115, a pigment that absorbs light within a light wavelength range of 400 to 700 nm is used as a dye. I. An optical film 126 was produced in the same manner except that the solvent was changed to Solvent Blue 63 (1-methylamino-4-[(3-methylphenyl) amino] -9,10-anthraquinone, maximum absorption wavelength 645 nm).

<Preparation of optical film 127>
In the production of the optical film 115, instead of providing the optical functional layer using the coating liquid 1 for forming the optical functional layer, the dispersion liquid 3 of vanadium dioxide-containing particles is further added to the adhesive layer coating liquid 1 in the light wavelength range of 400 to 700 nm. An optical film 127 was produced in the same manner except that the addition amount was adjusted so that the average optical absorptance of the optical film was 55%.

<Preparation of optical film 128>
In the production of the optical film 101, a transparent heat insulating layer containing airgel fine particles (thickness 8 μm, heat resistance 1) using a coating solution 1 for forming a transparent heat insulating layer having the following composition between the optical functional layer and the clear hard coat layer. 0.004 × 10 ⁻⁴ m ² · K / W), an optical film 128 was produced in the same manner.

[Transparent insulation layer forming coating solution 1]
5% by mass of polyvinyl alcohol (5% by mass aqueous solution, PVA-124: manufactured by Kuraray Co., Ltd.) 52 parts by mass Aerogel fine particles (IC3100 manufactured by Cabot) 2.3 parts by mass Surfactant (Adekapronic P-84: ADEKA) 1.5 parts by mass

<Preparation of optical films 129 and 130>
In the optical film 128, the thickness of the transparent heat insulating layer is 13 μm (thermal resistance 1.63 × 10 ⁻⁴ m ² · K / W) and 20 μm (thermal resistance 2.50 × 10 ⁻⁴ m ² · K / W), respectively. Optical films 129 and 130 were produced in the same manner except that the film was changed to.

<Evaluation>
<Evaluation 1>
Each optical film is bonded to the glass window on the south side of the room adjusted to 20 ° C with an air conditioner, and a fan (T-F55 from Toshiba Corp.) is placed at a position 2m away from the window as a model where the wind of the air conditioner directly hits. ), Wind is blown onto each optical film in three stages of strong, medium and weak memory, and the near-infrared light transmittance of each optical film at that time is measured with an ultraviolet-visible near-infrared spectrophotometer V-670 (JASCO) To make a phase transition (appearance of near-infrared light shielding effect), and evaluated according to the following evaluation criteria.
The evaluation results are shown in Table 1.

(Double-circle): The electric fan was brought close to 1 m, and a phase transition occurred even as a strong wind.
○: Phase transition occurred even in strong winds.
○ △: Phase transition occurs in medium wind, but no phase transition in strong wind.
Δ: A phase transition occurs if the wind is weak, but no phase transition occurs if the wind is medium.
X: No phase transition occurs even in weak winds.

<Evaluation 2>
The fan was not driven in the same place as in the above evaluation 1, the air conditioner was set to 28 ° C., and each optical film was exposed to sunlight for 30 minutes or more. At this time, all optical films had undergone a phase transition.
In this state, the blind was lowered to cut sunlight, and the time until the phase transition returned (expression of near-infrared light transmission effect) was measured and evaluated according to the following evaluation criteria.
The evaluation results are shown in Table 1.

○: Less than 15 minutes ○ △: 15 minutes or more and less than 30 minutes △: 30 minutes or more and less than 1 hour ×: 1 hour or more

<Summary>
As is apparent from Table 1, the optical film of the present invention is not suppressed in temperature rise even when it is used in a place where the air of the air conditioner directly hits, as compared with the optical film of the comparative example. It can be seen that near-infrared light can be effectively shielded.
From the above, it has an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties on a transparent substrate, and at least one transparent heat insulating layer is provided on the opposite side of the optical functional layer from the transparent substrate. It was confirmed that it was useful to provide an optical film that is hardly affected by the use environment.

The optical film of the present invention has a structure in which the optical functional layer containing the vanadium dioxide-containing particles is sandwiched between the transparent base material and the transparent base material, so that the glass window heated by sunlight is used. It was confirmed that the duration of the near-infrared light shielding effect can be shortened in an environment where the influence of residual heat is small and near-infrared light shielding is not required.

INDUSTRIAL APPLICABILITY The present invention is an optical film containing vanadium dioxide-containing particles that can adjust the near-infrared light shielding rate according to the temperature environment, and is particularly preferably used for providing an optical film that is not easily affected by the use environment. can do.

DESCRIPTION OF SYMBOLS 1 Optical film 2 Transparent base material 3 Optical functional layer 4 Colorant layer 5 Transparent heat insulation layer 6 Clear hard coat layer 7 Adhesive layer 10 Solvent displacement processing apparatus 11 Preparation kettle 12 Dispersion liquid 13 Circulation line 14 Circulation pump 15 Ultrafiltration part 16 Discharge port 17 Solvent stock pot 18 Solvent 19 Solvent supply line

Claims (4)

1. An optical film having an optical functional layer containing vanadium dioxide-containing particles having thermochromic properties on a transparent substrate,
   An optical film comprising at least one transparent heat insulating layer on the side of the optical functional layer opposite to the transparent substrate.
2. ^2. The optical film according to claim 1, wherein the heat resistance of the transparent heat insulating layer is in the range of 1.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ m ² · K / W.
3. The transparent substrate or the transparent heat insulating layer, or the layer between the transparent substrate and the transparent heat insulating layer contains a dye or pigment that absorbs light within a light wavelength range of 400 to 700 nm. The optical film according to claim 1, wherein the optical film is a film.
4. The average optical absorptance of the optical film within a light wavelength range of 400 to 700 nm is within a range of 20 to 80% at 23 ° C. The optical film described in 1.

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