JPWO2016158620A1 - Optical film - Google Patents

Abstract

An object of the present invention is to reverse the large change in the near-infrared light shielding rate and transmittance before and after the transition of vanadium dioxide in an optical film containing vanadium dioxide whose near-infrared shielding rate can be adjusted according to the temperature environment. It is to provide an optical film capable of controlling the transition without exerting a sufficient effect of thermodynamic properties and exhibiting a heat shielding property when the feeling of galling is strong even at a low temperature. . The optical film is an optical film containing vanadium dioxide fine particles having thermochromic properties, contains a dye or pigment that absorbs light within a light wavelength range of 650 to 700 nm, and falls within the light wavelength range. The optical film has an average light absorption rate of 30 to 85% at 23 ° C.

Description

  The present invention relates to an optical film, and more particularly to an optical film containing vanadium dioxide having thermochromic properties capable of adjusting the near-infrared shielding rate in accordance with the environmental temperature.

In recent years, laminated glass having high heat insulating properties or heat shielding properties, which blocks the heat felt by human skin due to the influence of sunlight entering from a car 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 a near-infrared light shielding film to a vehicle body or a window glass of a building, it is an effective means as an energy saving measure by reducing the load on cooling equipment such as an air conditioner in the vehicle.

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 middle to high latitude winter seasons, conversely, there is a problem that sunlight is shielded even 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. In other words, the optical film using the characteristics of VO ₂ can shield near-infrared light that causes heat at a high temperature, and can exhibit characteristics that transmit near-infrared light at a low temperature. This makes it possible to block near-infrared light when the summer is hot and suppress the temperature rise in the room, and to capture light energy when the winter is cold.

As a specific example of VO ₂ having such characteristics, a method of obtaining vanadium dioxide (VO ₂ ) nanoparticles by hydrothermal synthesis from a vanadium compound and hydrazine or a hydrate thereof is disclosed ( For example, see Patent Document 1).
Moreover, it is possible to provide a thermochromic film by dispersing VO ₂ nanoparticles prepared by the hydrothermal synthesis method in a transparent resin to form a VO ₂ dispersed resin layer on a transparent substrate. A possible method is disclosed (for example, see Patent Document 2).

According to these documents, in order to control the transition temperature of vanadium dioxide (VO ₂ ) to a preferable temperature, specifically, doping of tungsten (W) or molybdenum (Mo) is performed to lower the transition temperature. .
However, the transition temperature can be lowered by doping the metal, but the effect of the thermochromic effect is reduced because the large change width of the shielding ratio and transmittance of near-infrared light before and after the transition is reduced. was there.
In addition, even when the temperature is relatively low, for example, in the early spring of Japan, there is a problem that the heat shielding property does not appear when the solar radiation is strong.

JP2011-178825A JP2013-184091A

  The present invention has been made in view of the above-mentioned problems, and the problem is that in an optical film containing vanadium dioxide capable of adjusting the near-infrared light shielding rate according to the environmental temperature, the near red before and after the transition of vanadium dioxide. It can control the transition without losing the large change in the shielding ratio and transmittance of outside light, and can fully exert the effect of thermodynamics. It is providing the optical film which can express.

  As a result of intensive studies in view of the above problems, the present inventor contains vanadium dioxide fine particles having thermochromic properties and a dye or pigment that absorbs light within a specific wavelength range, and the light wavelength range is within the range. By controlling the average optical absorptance of the optical film within a specific range at a specific temperature, the transition can be controlled without losing the change range of the shielding effect and transmission effect of near-infrared light before and after the transition of vanadium dioxide. The present inventors have found that the thermochromic effect can be sufficiently exerted, and that the heat shielding property can be expressed when the tingling feeling is strong even at a low temperature, and the present invention has been achieved.

That is, the said subject of this invention is solved by the following means.
1. An optical film containing vanadium dioxide fine particles having thermochromic properties,
Containing a dye or pigment that absorbs light in the light wavelength range of 650-700 nm, and
The optical film having an average light absorptance of the optical film in the light wavelength range of 30 to 85% at 23 ° C.

  2. 2. The optical system according to item 1, wherein the dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is a dye or pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm. the film.

  3. Item 1 or Item 2 wherein the dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is a pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm. Optical film.

  4). 4. The optical film according to item 3, wherein the pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm is a metal phthalocyanine pigment.

  5. The optical system according to any one of items 1 to 4, wherein the number average primary particle size of pigment particles constituting the pigment is smaller than the number average primary particle size of the vanadium dioxide fine particles. the film.

  6). The dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is contained in the same layer as the layer containing the vanadium dioxide fine particles or in an adjacent layer in direct contact with the layer containing the vanadium dioxide fine particles. The optical film according to any one of items 1 to 5, wherein the optical film is characterized in that:

  7). The optical film according to any one of Items 1 to 6, wherein 99.5 atomic% or more of the metal component of the vanadium dioxide fine particles is vanadium.

  8). The optical film according to any one of Items 1 to 7, wherein the optical film has a spectral transmittance of 50% or more at 23 ° C. at an optical wavelength of 1300 nm.

  9. The average optical absorptance of the optical film within a light wavelength range of 650 to 700 nm is within a range of 50 to 70% at 23 ° C., any one of items 1 to 8 The optical film described in 1.

  10. The optical film according to any one of Items 1 to 9, wherein a spectral transmittance of the optical film at a light wavelength of 550 nm is within a range of 30 to 60% at 23 ° C.

By the above-mentioned means of the present invention, the transition can be controlled and the effect of thermochromic properties can be sufficiently exhibited without losing the large change width of the near-infrared light shielding rate and transmittance before and after the transition of vanadium dioxide. In addition, it is possible to provide an optical film capable of exhibiting heat-shielding properties when the feeling of galling is strong even at low temperatures.
The expression mechanism / action mechanism that has achieved the above-described object effect of the present invention is not clear, but is presumed as follows.
Since the optical film of the present invention contains thermochromic vanadium dioxide fine particles and a dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm, the solar heat absorbed by the dye or pigment is efficiently absorbed. It can be transferred to vanadium dioxide fine particles. Moreover, the optical film of this invention absorbs a solar heat efficiently because the average light absorptivity in the range of the light wavelength of 650-700 nm in 23 degreeC is in the range of 30 to 85%, and an optical film is optical. The temperature of the optical film rises before the environmental temperature where the film is placed. As a result, the ambient temperature is somewhat lower without doping the vanadium dioxide fine particles with a metal such as tungsten (W) or molybdenum (Mo) to lower the transition temperature and lower the thermochromic properties. However, thermochromic properties appear when the sun is strong, and it shields sunlight.
Thus, by containing the dye or pigment and making the average light absorptance in the range of 30 to 85%, the near-infrared light shielding rate and transmittance before and after the transition of vanadium dioxide are large. Without losing the change width, the transition temperature can be controlled so that the effect of thermochromic properties can be sufficiently exerted, and when the temperature is low, the thermal barrier property can be expressed when the sensation is strong.

Schematic sectional view showing an example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration of the optical film of the present invention Schematic sectional view showing another example of the basic configuration 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 is an optical film containing vanadium dioxide fine particles having thermochromic properties, contains a dye or pigment that absorbs light within a light wavelength range of 650 to 700 nm, and the light wavelength range. The average optical absorptance of the optical film is within a range of 30 to 85% at 23 ° C. This feature is a technical feature common to the inventions according to claims 1 to 10.
As an embodiment of the present invention, the dye or pigment that absorbs light within the light wavelength range of 650 to 700 nm is within the light wavelength range of 600 to 750 nm from the viewpoint of more manifesting the intended effect of the present invention. A dye or pigment having a maximum absorption wavelength is preferred. Thereby, the light within the light wavelength range of 650 to 700 nm can be efficiently absorbed.

  The dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is preferably a pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm. That is, the dye system absorbs the absorbed energy immediately and reaches a uniform temperature, whereas the pigment system increases the temperature as particles, and the temperature near the particles can be increased. Is preferable.

  In addition, the pigment having the maximum absorption wavelength within the light wavelength range of 600 to 750 nm is preferably a metal phthalocyanine pigment in view of the high extinction coefficient and weather resistance.

  In addition, the fact that the number average primary particle size of the pigment particles constituting the pigment is smaller than the number average primary particle size of the vanadium dioxide fine particles, the balance of heat absorption and release of the pigment particles and vanadium dioxide fine particles, This is preferable in that the solar heat absorbed by the particles can be efficiently transferred to the vanadium dioxide fine particles.

  Further, the dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is in the same layer as the layer containing the vanadium dioxide fine particles, or an adjacent layer in direct contact with the layer containing the vanadium dioxide fine particles. It is preferable that it is contained because the solar heat absorbed by the dye or pigment can be efficiently transferred to the vanadium dioxide fine particles.

  Further, if 99.5 atomic% or more of the metal component of the vanadium dioxide fine particles is vanadium, the change width of the shielding effect and the transmission effect before and after the transition of the vanadium dioxide fine particles is increased, and the effect of thermochromic properties is increased. It is preferable in that it can be performed.

Moreover, it is preferable that the spectral transmittance of the optical film at a light wavelength of 1300 nm is 50% or more at 23 ° C. because the shielding effect and the transmission effect before and after the transition of the vanadium dioxide fine particles can be effectively used.
In order to obtain sufficient heat shielding properties, the spectral transmittance of the optical film at a light wavelength of 1300 nm is preferably 40% or less at 70 ° C.

  In addition, the optical film absorbs solar heat more efficiently when the average optical absorptance of the optical film within a light wavelength range of 650 to 700 nm is within a range of 50 to 70% at 23 ° C. When it is strong, chromic properties are exhibited, which is preferable in terms of sunlight shielding properties.

  Moreover, it is preferable from the point of coloring of an optical film that the spectral transmittance of the said optical film in optical wavelength 550nm is in the range of 30 to 60% in 23 degreeC.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Outline of optical film>
The optical film of the present invention is an optical film containing vanadium dioxide fine particles having thermochromic properties, and absorbs light within a light wavelength range of 650 to 700 nm (hereinafter simply referred to as “dye or pigment”, Or the “coloring agent”), and the average optical absorptance of the optical film within the light wavelength range is within a range of 30 to 85% at 23 ° C.

The average light absorption rate within the light wavelength range of 650 to 700 nm can be determined as follows.
Average light absorptance in the range of light wavelength 650 to 700 nm = 100 − {(Average spectral transmittance in the range of light wavelength 650 to 700 nm) − (Average spectral reflectance in the range of light wavelength 650 to 700 nm)}
In addition, the measurement of an average spectral transmittance and an average spectral reflectance can be measured using a spectrophotometer. In this invention, it measured using JASCO Corporation ultraviolet visible near-infrared spectrophotometer V-670. After setting the temperature in the temperature-controlled room to 23 ° C. and the humidity 55RH so that the temperature of the film would be 23 ° C., the measurement sample (optical film) was left in the temperature-controlled room for 3 hours to be in an equilibrium state. The above measurements were made.

Further, the average light absorptance within the light wavelength range of 650 to 700 nm is more preferably within a range of 50 to 70% at 23 ° C. in terms of more efficiently absorbing solar heat.
Further, it is preferable that the spectral transmittance at a light wavelength of 1300 nm is 50% or more at 23 ° C. because the shielding effect and the transmission effect before and after the transition of the vanadium dioxide fine particles can be effectively used.
Further, the spectral transmittance at a light wavelength of 550 nm is preferably in the range of 30 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 absorptivity within the range of the light wavelength of 650 to 700 nm within the range of 30 to 85%, for example, by adjusting the coating amount of the coating liquid containing the 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.

The dye or pigment that absorbs light within the light wavelength range of 650 to 700 nm in the present invention is not particularly limited as long as it is a material that absorbs light within the range of 650 to 700 nm, but has maximum absorption within the range of 600 to 750 nm. A dye or pigment having a wavelength is more preferable because it can efficiently absorb light in the range of 650 to 700 nm.
In the present invention, the “dye” refers to a dye that 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 600 to 750 nm include anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, triarylmethane dyes, and indigo dyes. Etc.
Anthraquinone dyes include, for example, C.I. I. Solvent Blue 35 (maximum absorption wavelength 623, 670 nm), C.I. I. Solvent Blue 36 (maximum absorption wavelength 643 nm), C.I. I. Solvent Blue 59 (maximum absorption wavelength 645 nm), C.I. I. Solvent Blue 63 (maximum absorption wavelength 645 nm), C.I. I. Solvent Blue 87 (maximum absorption wavelength 630 nm), C.I. I. Solvent Green 3 (maximum absorption wavelength 642 nm), C.I. I. Solvent Green 20 (maximum absorption wavelength 685 nm), C.I. I. Disperse blue 14 (maximum absorption wavelength 647 nm) and the like can be mentioned.
Examples of the phthalocyanine dye include C.I. I. Solvent Blue 67 (maximum absorption wavelength 624, 670 nm), C.I. I. Solvent Blue 70 (maximum absorption wavelength 624, 670 nm) and the like can be mentioned.
Examples of the triphenylmethane dye include C.I. I. Solvent Blue 5 (maximum absorption wavelength 627 nm) and the like can be mentioned.

Further, as pigments, compounds classified as pigments in the color index (CI; issued by The Society of Dyers and Colorists), specifically, the following color index (C.I. ) Can be listed.
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. I. Pigment green 7, C.I. I. Pigment green 36; C.I. I. Pigment brown 23, C.I. I. Pigment brown 25; C.I. I. Pigment Black 1, Pigment Black 7
Among them, copper phthalocyanine-based C.I. I. Pigment blue 15: 3 (maximum absorption wavelength 630, 720 nm), C.I. I. Pigment Blue 15: 4 (maximum absorption wavelength 640, 740 nm), C.I. I. Pigment Blue 16 (maximum absorption wavelength 620, 690 nm) or the like can be preferably used.

In the present invention, it is preferable to use a pigment rather than the above-mentioned dye. In particular, a metal phthalocyanine pigment is more preferable in view of the high extinction coefficient and weather resistance.
The mechanism by which pigment systems are preferred over dye systems is not clearly understood, but dye systems quickly diffuse the absorbed energy to a uniform temperature, while pigment systems have a temperature as particles. It is preferable in that it rises and the vicinity of the particles can be heated to a higher temperature.

Moreover, in this invention, since the dye or pigment which absorbs the light within the range of the light wavelength 650-700 absorbs light, and it colors as a green system as an optical film, further, the dye which absorbs green, or It is more preferable to use a pigment in combination so that the spectral transmittance at a light wavelength of 550 nm at a film temperature of 23 ° C. is 30 to 60%, which is close to gray.
Examples of the green pigment include C.I. I. Pigment green 36, C.I. I. A green pigment containing a compound in which the central metal in Pigment Green 36 is a metal other than Cu, such as Zn; I. Pigment green 7, C.I. I. Pigment red 122, C.I. I. And CI Pigment Red 254.

<< Layer structure of optical film >>
The optical film of the present invention is characterized in that any layer constituting the optical film contains thermochromic vanadium dioxide fine particles and the dye or pigment.
The layer containing the vanadium dioxide fine particles having thermochromic properties and the layer containing the dye or pigment may be the same layer or different layers, but contain the dye or pigment. The layer is preferably the same layer as the layer containing vanadium dioxide fine particles or an adjacent layer in direct contact with the layer containing vanadium dioxide fine particles. This is because the solar heat absorbed by the dye or pigment can be efficiently transferred to the vanadium dioxide fine particles.

Typical configurations of the optical film of the present invention include the following configurations (1) to (7), but are not limited thereto.
(1) Colorant layer / hard coat layer containing the dye or pigment / transparent substrate / optical functional layer containing the vanadium dioxide fine particles / adhesive layer (see FIG. 1A)
(2) Hard coat layer / transparent substrate / optical functional layer containing the vanadium dioxide fine particles / colorant layer / adhesive layer containing the dye or pigment (see FIG. 1B)
(3) Hard coat layer / transparent substrate / optical functional layer containing the vanadium dioxide fine particles / colorant layer / adhesive layer containing the dye or pigment (see FIG. 1C)
(4) Hard coat layer / transparent substrate / colorant layer / optical functional layer / adhesive layer containing the vanadium dioxide fine particles and the dye or pigment (see FIG. 1D)
(5) Hard coat layer / Optical functional layer / transparent substrate containing vanadium dioxide fine particles / Colorant layer / adhesive layer containing the dye or pigment (see FIG. 1E)
(6) Colorant layer / hard coat layer containing the dye or pigment / Optical functional layer / transparent substrate / adhesive layer containing the vanadium dioxide fine particles (see FIG. 1F)
(7) Hard coat layer / colorant layer containing the vanadium dioxide fine particles and the dye or pigment, and optical functional layer / transparent substrate / adhesive layer (see FIG. 1G)
In addition, the adhesion layer can be affixed on glass (for example, glass 7 shown to FIG. 1A-FIG. 1G). Hereinafter, the configurations of (1) to (7) will be described.

  In the optical film 1 shown in FIG. 1A, the optical functional layer 3 containing the vanadium dioxide fine particles having thermochromic properties and the adhesive layer 5 are laminated in this order on one surface of the transparent substrate 2. The hard coat layer 4a containing a dye or pigment that absorbs light within a light wavelength range of 650 to 700 nm is laminated on the surface.

The optical function layer 3 is present in a state where vanadium dioxide fine particles are dispersed in a binder resin.
In the hard coat layer 4a, the dye or pigment is present in a dispersed state.

  In the present invention, the number average particle diameter of primary particles of vanadium dioxide in the optical functional layer 3 is preferably larger than the number average particle diameter of primary particles of pigment particles constituting the pigment.

  In the present invention, the average particle size of the vanadium dioxide fine particles in the optical functional layer 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 by a microtome to produce an ultrathin section having a cross section as shown in FIG. 1A. Next, the ultrathin section is photographed at 10,000 to 100,000 times using a transmission electron microscope (TEM). The particle diameter of the primary particles of vanadium dioxide fine particles present as single particles existing in a certain region of the photographed cross section is measured. At this time, the vanadium dioxide fine particles to be measured are preferably in the range of 50 to 100. If it is not spherical, the projected area of the particle is converted into a circle, and its diameter is taken as the particle size. For each primary particle diameter, the number average diameter is determined. 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 the number-average particle size (nm) referred to in the present invention. It was.

Although details of the vanadium dioxide fine particles according to the present invention will be described later, the primary particle diameter is preferably in the range of 5 to 100 nm.
Moreover, it is preferable that the particle diameter of the primary particle of the pigment particle which comprises a pigment exists in the range of 1-100 nm. The average particle diameter of the pigment particles can be determined, for example, by observing an ultrathin section with a transmission electron microscope in the same manner as the primary particle diameter of the vanadium dioxide fine particles.

In the optical film 1 shown in FIG. 1B, the dye or pigment is contained in the adhesive layer 5b which is an adjacent layer in direct contact with the optical functional layer 3 containing vanadium dioxide fine particles.
In the optical film 1 shown in FIG. 1C, the dye or pigment is contained in the colorant layer 6 that is an adjacent layer in direct contact with the optical functional layer 3 containing vanadium dioxide fine particles, and on the colorant layer 6. Further, an adhesive layer 5 is formed.
In the optical film 1 shown in FIG. 1D, the dye or pigment is contained in the same layer as the optical functional layer 3d containing vanadium dioxide fine particles.
In the optical film 1 shown in FIG. 1E, the dye or pigment is contained in the colorant layer 6 which is an adjacent layer in direct contact with the optical functional layer 3 and the transparent substrate 2 containing vanadium dioxide fine particles. An adhesive layer 5 is further formed on the agent layer. This optical film has a hybrid structure in which the transparent substrate 2 also serves as the optical functional layer 3.
In the optical film 1 shown in FIG. 1F, the dye or pigment is contained in the hard coat layer 4f that directly contacts the optical functional layer 3 and the transparent substrate 2 containing vanadium dioxide fine particles. This optical film has a hybrid structure in which the transparent substrate 2 also serves as the optical functional layer 3.
The optical film 1 shown in FIG. 1G is a case where the dye or pigment is contained in the same layer as the optical functional layer 3g and the transparent base material 2g containing vanadium dioxide fine particles. This optical film 1 is also a transparent base material. 2 g is a hybrid structure that also serves as the optical functional layer 3 g.

1B and 1C, and the optical functional layer 3d shown in FIG. 1D, vanadium dioxide fine particles are dispersed in the binder resin, similarly to the optical functional layer 3 shown in FIG. 1A. Exists. In addition, dye or a pigment is not contained in the hard-coat layer 4 shown to FIG.
Further, the optical functional layer 3 / transparent substrate 2 shown in FIGS. 1E and 1F and the optical functional layer 3g / transparent substrate 2g shown in FIG. 1G are contained in the transparent substrate 2 or the polymer constituting the transparent substrate 2g. In addition, vanadium dioxide fine particles are present in a dispersed state.

<Each film material>
Hereinafter, details of the optical functional layer, which is a constituent element of the optical film of the present invention, a transparent substrate provided as necessary, a colorant layer, an adhesive layer, a hard coat layer, and a near-infrared light shielding layer will be described.

[Optical function layer]
The optical functional layer according to the present invention contains vanadium dioxide fine particles and a binder resin.
As described above, the same layer as the optical functional layer containing the vanadium dioxide fine particles may contain a dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm, It may contain dyes or pigments.
As the binder resin, an aqueous binder resin or a hydrophobic binder resin can be used as will be described later.

  As a method of forming an optical functional layer in the case of using an aqueous binder resin, vanadium dioxide fine particles exist without being associated with each other without preparing a drying step after preparing vanadium dioxide fine particles by an aqueous synthetic method. An aqueous optical functional layer forming coating liquid is prepared by mixing an aqueous binder resin solution prepared by dissolving an aqueous binder resin in an aqueous solvent in the state of the dispersion liquid, and this optical functional layer forming coating liquid. A method of forming an optical functional layer by coating and drying on a transparent substrate by a wet coating method is preferred.

  On the other hand, as a method for forming an optical functional layer in the case of using a hydrophobic binder resin, vanadium dioxide fine particles are prepared by a solvent substitution step without preparing a drying step after preparing vanadium dioxide fine particles by an aqueous synthesis method. After preparing the solvent dispersion, mix and dissolve with a hydrophobic binder resin, etc. to prepare a non-aqueous optical functional layer-forming coating solution. This non-aqueous optical functional layer-forming coating solution is prepared by a wet coating method. A method of forming an optical functional layer by coating and drying on a transparent substrate is preferred.

The vanadium dioxide fine particles and the binder resin will be described in order.
[Vanadium dioxide fine particles]
The crystal form of the vanadium dioxide fine particles according to the present invention is not particularly limited, but rutile vanadium dioxide fine particles (VO ₂ fine particles) may be used from the viewpoint of efficiently expressing thermochromic properties (automatic light control). Is particularly preferred.

Since the rutile VO ₂ fine particles have a monoclinic structure below the transition temperature, they are also called M-type. The vanadium dioxide fine particles according to the present invention may contain VO ₂ fine particles of other crystal type such as A-type or B-type within a range that does not impair the purpose.

  In the present invention, it is preferable that 99.5 atomic% or more of the metal component of the vanadium dioxide fine particles is vanadium, and thereby, good thermochromic properties can be exhibited. That is, when a metal other than vanadium is doped, it is sufficient if it is doped with less than 0.5 atomic%. Besides vanadium, for example, tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir), osmium (Os), ruthenium ( At least one element selected from the group consisting of Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F) and phosphorus (P). It may be included.

  Further, the aspect ratio of the vanadium dioxide fine particles is preferably in the range of 1.0 to 3.0.

  The vanadium dioxide fine 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 fine particles.

  Further, the concentration of the vanadium dioxide fine particles in the optical functional layer according to the present invention is not particularly limited, but is preferably in the range of 5 to 60% by mass with respect to the total mass of the optical functional layer, more preferably. It exists in the range of 5-40 mass%, More preferably, it exists in the range of 5-30 mass%.

(1: Method for producing vanadium dioxide fine particles)
In general, a method for producing vanadium dioxide fine particles includes a method of pulverizing a VO ₂ sintered body synthesized by a solid phase method, and a vanadium compound such as divanadium pentoxide (V ₂ O ₅ ) or ammonium vanadate as a raw material. An aqueous synthesis method in which particles are grown while synthesizing VO ₂ in the liquid phase can be mentioned.

  The method for producing the vanadium dioxide fine particles according to the present invention is a method in which vanadium dioxide fine particles are synthesized using a vanadium compound as a raw material while synthesizing vanadium dioxide fine particles in a liquid phase in that the average primary particle size is small and variation in particle size can be suppressed. A growing aqueous synthesis method is preferred.

  Furthermore, examples of the aqueous synthesis method include a hydrothermal synthesis method and an aqueous synthesis method using a supercritical state. Details of the hydrothermal synthesis method will be described later. The details of the water-based synthesis method using the supercritical state (also referred to as supercritical hydrothermal synthesis method) are disclosed in, for example, paragraph numbers (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 fine particles, if necessary, fine TiO ₂ fine particles that become the core of particle growth are added as core particles, and vanadium dioxide fine particles are produced by growing the core particles. You can also.

  Next, the details of the method for producing vanadium dioxide fine particles by the hydrothermal method suitable for the present invention will be described.

  Below, the manufacturing process of the vanadium dioxide fine particle by a typical hydrothermal 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 an element to be added in order to add an 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 substance C having oxidizing property or reducing property, 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 exists in the range of 250-300 degreeC, More preferably, it exists in the range of 250-280 degreeC. 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. Moreover, it is preferable that the time of a hydrothermal reaction process exists in the range of 1 hour-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 fine particles may be subjected to a coating treatment or a surface modification treatment with a resin. Thereby, the surface of vanadium dioxide fine particles is 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 fine particles is coated with the same or the same kind of resin as the aqueous binder resin. 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 fine 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 liquid containing single crystal fine particles containing thermochromic vanadium dioxide (VO ₂ ) is obtained.

<Removal of impurities from vanadium dioxide fine particle dispersion>
The dispersion of vanadium dioxide fine particles prepared by the above-mentioned aqueous synthesis method contains impurities such as residues generated in the synthesis process, and triggers the generation of secondary agglomerated particles when forming the optical functional layer. Thus, it may become a deterioration factor in long-term storage of the optical functional layer, and it is preferable to remove impurities in advance at the stage of the dispersion.

  As a method for removing impurities in the vanadium dioxide fine particle dispersion, a conventionally known means for separating foreign substances and impurities can be applied. For example, the vanadium dioxide fine particle dispersion is centrifuged to precipitate the vanadium dioxide fine particles. It is possible to remove impurities in the supernatant and add and disperse the dispersion medium again, or to remove impurities out of the system using an exchange membrane such as an ultrafiltration membrane. From the viewpoint of preventing aggregation, the method using an ultrafiltration membrane is most preferable.

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

(2: Preparation method of solvent dispersion containing vanadium dioxide fine particles: solvent substitution treatment)
In the present invention, when a hydrophobic binder resin is used, after preparing an aqueous dispersion containing vanadium dioxide fine particles by the above aqueous synthesis method, the vanadium dioxide fine particles are not subjected to a drying process as a water-based dispersion. It is preferable to prepare a solvent dispersion containing vanadium dioxide fine particles by the substitution step.

  The solvent replacement step is composed of a concentration step of concentrating the dispersion containing vanadium dioxide fine particles and a solvent dilution step of adding and diluting the solvent to the concentrate, and includes 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 fine particles.

  The concentration means used in the concentration step of the specific dispersion containing vanadium dioxide fine particles is preferably an ultrafiltration method.

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

  The solvent applicable in the solvent substitution treatment according to the present invention is an organic solvent, and preferably a non-aqueous organic solvent. Finally, it is a step of preparing a solvent dispersion containing vanadium dioxide fine particles by replacing water, which is a medium constituting the aqueous dispersion containing vanadium oxide-containing fine 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.

  A specific solvent replacement process 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 adjusts the preparation tank 11 for storing the dispersion liquid 12 containing the vanadium dioxide fine particles prepared above, the solvent stock tank 17 for storing the solvent 18 for dilution, and the solvent 18. An ultrafiltration unit 15 is disposed as a concentrating means in the route of the circulation line 13 for circulating the solvent supply line 19 to be added to the pot 11 and the preparation tank 11 by the circulation pump 14.

  Step (A) The dispersion liquid containing the vanadium dioxide fine particles prepared by the above method is stored as the dispersion liquid 12 in the preparation kettle 11 and is circulated by the circulation pump 14. Water 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.

  Step (B) Next, 80% by mass of the solvent 18 is added from the solvent stock kettle 17 via the solvent supply line 19 to the dispersion 12 concentrated to 20% by volume, and sufficiently stirred and mixed. A primary solvent-substituted dispersion 12 is prepared.

  Step (C) Next, in the same manner as in the above step (A), the medium (water + solvent) in the dispersion is discharged 16 outside the system by the ultrafiltration unit 15 while being circulated by the circulation pump 14. Concentrate again to a concentration of 20% by volume.

  Step (D) Next, in the same manner as in the above step (B), 80% by mass of the solvent 18 is added from the solvent stock kettle 17 via the solvent supply line 19 to the concentrated dispersion, and the mixture is sufficiently stirred. Mixing is performed to prepare the first solvent-substituted dispersion liquid 12.

  Step (E) Finally, the concentration and solvent dilution operations in Step (A) and Step (B) are repeated at least twice, so that the water content is within the range of 0.1 to 5.0% by mass. A solvent dispersion containing the adjusted vanadium dioxide fine particles is prepared. The water content can be determined by measuring, for example, by the Karl Fischer method.

  That is, the solvent dispersion liquid containing vanadium dioxide fine 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. It is as follows. 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 moisture content is preferably in the range of 0.01 to 30% by mass, and particularly preferably in the range of 0.1 to 5.0% by mass. 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. % Or more, the change width between the infrared transmittance and the infrared 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 oxidation of the vanadium dioxide fine particles and the film forming property of the coexisting hydrophobic binder, and to maintain the haze at a lower level. be able to. Moreover, by setting it as 0.1 mass% or more, the change width of the infrared rays transmittance | permeability and infrared shielding factor at the time of a temperature change can further be expanded, and it is preferable conditions.

  Examples of the ultrafiltration method used in the 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 at 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 , fractional molecular weight 5000) manufactured by Sartorius steady is used as a filtration membrane, and ultrafiltration is performed at a flow rate of 300 ml / min (minutes), a hydraulic pressure of 100 kPa, and room temperature. Examples thereof include an ultrafiltration device having a filtration membrane made of polyethersulfone and 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 fine particles by an aqueous synthesis method, a hydrophobic binder resin should be used when preparing a solvent dispersion containing vanadium dioxide fine particles by the solvent replacement step. It is preferable to use an aqueous binder resin when the solvent replacement step is not performed.

[Water-based binder resin]
The aqueous 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., 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, natural 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, or acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid Acid-acrylic acid esthetic Styrene acrylate resin such as copolymer, styrene-α-methylstyrene-acrylic acid copolymer, or styrene-α-methylstyrene-acrylic acid-acrylic ester copolymer, styrene-sodium styrenesulfonate copolymer Styrene-2-hydroxyethyl acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid Vinyl acetate copolymers such as copolymers, vinyl naphthalene-maleic acid copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers, and the like Of the salt.

  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 fine particles and has a high effect of preventing particle aggregation even during drying of film formation, is preferable. Examples thereof include celluloses, polyvinyl alcohols, acrylic resins having a hydroxy group, etc. 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.

(Polyvinyl alcohols)
As the polyvinyl alcohol 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-61-110483, and the main chain or side chain of the polyvinyl alcohol. 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, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

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

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

(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, carboxymethylcellulose (cellulose carboxymethyl ether), methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, Examples thereof include water-soluble cellulose derivatives such as hydroxypropylmethylcellulose, carboxymethylcellulose (cellulose carboxymethyl ether) and carboxyethylcellulose 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 water-based 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 types. It has a hydroxy group, 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.

(Gelatin)
As the gelatin applicable to the present invention, various gelatins that have been widely used in the field of silver halide photographic light-sensitive materials can be applied. For example, in addition to acid-processed gelatin and alkali-processed gelatin, production of gelatin is possible. Enzyme-treated gelatin and gelatin derivatives that undergo enzyme treatment in the process, that is, modified with a reagent that has an amino group, an imino group, a hydroxy group, or a carboxy group as functional groups in the molecule and has groups obtained by reaction with them. It may be quality. 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 (Macmillan) 55, Science Photo Handbook (above) 72-75 (Maruzen), Fundamentals of Photographic Engineering-Silver Salt Photo Hen 119-124 (Corona). Also, Research Disclosure Magazine Vol. 176, No. And gelatin described in Section IX of 17643 (December, 1978).

  When gelatin is used as the water-based 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, vinylsulfone 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.

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

  The thickening polysaccharide referred to in the present invention is a polymer of saccharides and has 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 adding metal oxide fine particles, it causes a viscosity increase that seems to be due to hydrogen bonding with the metal oxide fine particles at a low temperature. It is a polysaccharide that causes an increase in viscosity at 15 ° C. of 1.0 mPa · s or more by addition, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more. Polysaccharides.

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

(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-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer. Acrylic resins such as polymers, vinyl acetate-acrylic acid ester copolymers, or acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic Styrene acrylic acid resin such as acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer Polymer, styrene-2-hydroxy Ethyl acrylate copolymer, styrene-2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene -Vinyl acetate copolymers such as maleic acid copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, and salts thereof. 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 paragraph numbers (0049) to (0052) of International Publication No. 2011/148931 can be referred to.

[Hydrophobic binder resin]
The hydrophobic binder resin in the present invention 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, more preferably a resin having a dissolution amount of less than 0.5 g. More preferably, it is a resin having a dissolution amount of less than 0.25 g.

  The hydrophobic binder resin is preferably a resin polymerized 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 olefin-based polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (4-methyl-1-pentene), acrylate-based copolymers; Halogen-containing polymers such as vinyl and chlorinated vinyl resins; polystyrene-based 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; Ether ketone; Polysulfone; Polyethersulfone; Polyoxybenzylene; Polyamideimide; ABS resin (acrylonitrile-butadiene-styrene resin) and ASA resin (acrylonitrile-styrene-acrylate resin) blended with polybutadiene rubber and acrylic rubber, Cellulosic resins, butyral resins, and the like can be given.

  In addition, as a kind of hydrophobic binder resin applicable to the present invention, a resin that uses a monomer of a hydrophobic binder resin and is polymerized in a curing treatment step can be exemplified, and its representative hydrophobic binder resin material Is a compound that is cured by irradiation with active energy rays, and specifically includes 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. be able to.

  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-methylol acrylamide, diacetone acrylamide, 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.

  Various known cationic polymerizable monomers can be used as the cationic polymerizable compound. For example, the epoxies exemplified in JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, JP-A-2001-220526 Compounds, vinyl ether compounds, oxetane compounds and the like.

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

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

  As the light source of the active energy ray, in the case of 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. 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 amount of 1 to 5 Mrad.

  As shown in FIGS. 1E to 1G, when the transparent base material has a hybrid structure also serving as an optical functional layer, a solvent dispersion containing vanadium dioxide fine particles in a hydrophobic resin that is a constituent material of the transparent base material And a solvent is added and dissolved to prepare a dope for film formation, and then the optical film can be suitably formed by the solution casting method used in the conventional film formation using the dope. it can.

  Examples of the hydrophobic binder resin that can be applied by the above method include resin materials that are conventionally used in the formation of optical films, such as polyethylene, polypropylene, cellulose diacetate, cellulose triacetate (abbreviation: TAC), Cellulose acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate (Abbreviation: PC), norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone (abbreviation: PES), polyphenylenesulfur , Polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic and polyarylates, Arton (trade name, manufactured by JSR) and Appel (trade name, manufactured by Mitsui Chemicals) And the like.

  Further, the solvent is not particularly limited. For example, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2- Trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2- Examples include propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, and the like.

  Using the dope prepared by mixing and preparing the above constituent materials, a hybrid optical functional layer that also serves as a transparent substrate is formed by a solution casting method.

[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, and JP-A-62-261476, JP-A-57-74192, and JP-A-57-87989. , JP-A-60-27285, JP-A-61-14659, JP-A-1-95091, JP-A-3-13376, etc. Or various nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, and JP-A-4-219266. Optical brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, etc. Lubricants such as tylene glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, thickeners, lubricants, infrared absorption Examples include various known additives such as agents, 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 which concerns on this invention, As above-mentioned, it differs with the case where a water-based binder resin is used, and the case where a hydrophobic binder resin is used.
In the case of using an aqueous binder resin, after preparing vanadium dioxide fine particles by an aqueous synthesis method, without passing through a drying step, in a state of dispersion in which vanadium dioxide fine particles are present without being associated, A water-based binder resin solution prepared by dissolving a water-based binder resin in a water-based solvent is mixed to prepare a water-based optical functional layer-forming coating solution, and this optical functional layer-forming coating solution is transparent by a wet coating method. A method of forming an optical functional layer by applying and drying on a substrate is preferred.

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

  Further, as a method of forming a hybrid optical functional layer that also serves as a transparent substrate, a solution casting method can be applied. As a specific film forming method, for example, JP2013-067074A, Solution casting film forming methods described in JP 2013-123868 A, JP 2013-202979 A, JP 2014-0669958 A, JP 2014-095729 A, JP 2014-159082 A, etc. Can be formed according 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. “Transparent” in the present invention means that the average light transmittance in the visible light region is 50% or more, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

  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, it is more preferable that it is in the range of 1.5 to 3.0%, and it is more preferable that it is 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 the undercoat layer coating solution in-line on one or both sides during the film forming process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating.

<Colorant layer>
In the present invention, among the layer structures of the optical film, as in the layer structure of (3) or (5) (see FIG. 1C or FIG. 1E), the dye or pigment according to the present invention contains vanadium dioxide. The colorant layer may be contained as an adjacent layer in direct contact with the optical functional layer. As the binder of the colorant layer, for example, the aforementioned hydrophobic binder resin can be used.

《Hard coat layer》
In the present invention, among the layer configurations of the optical film, the above-described dye or pigment according to the present invention is applied to the hard coat layer as in the layer configuration of (1) or (6) (see FIG. 1A or 1F). You may make it contain.

As the hard coat material of the hard coat layer (also referred to as HC layer) in the present invention, an inorganic material typified by polysiloxane, an active energy ray curable resin, or the like can be used.
The inorganic material needs to be moisture-cured (from room temperature to warming), and it is preferable to use an active energy ray-curable resin in the present invention from the viewpoint of curing temperature, curing time, and cost. 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 or 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, ultraviolet curable acrylate resins are preferred. UV curable acrylic urethane resins generally include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylates) in addition to products obtained by reacting polyester polyols with isocyanate monomers or prepolymers. It 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 Unidic 17-806 (manufactured by DIC Corporation) and 1 part of Coronate L (manufactured by Tosoh Corporation) described in JP-A-59-151110 is preferably used. The UV 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 a carboxy group at the end of the polyester. 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 it adhere to the optical film of this invention, another base material, etc. 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 configurations of the optical film, as in the layer configuration of (2) above (see FIG. 1B), the above-described dye or pigment according to the present invention is directly applied to the optical functional layer containing vanadium dioxide. You may make it contain in an adhesion layer as an adjacent layer which contacts.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer is selected from rubber-based, acrylic-based, silicon-based and urethane-based pressure-sensitive adhesives. Acrylic and silicon-based materials are preferred because yellowing does not occur over time, and acrylic-based materials are most preferable in that a general-purpose release sheet can be used.
The thickness of the adhesive layer is preferably in the range of 5 μm 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 attached to the adhesive layer, it is possible to use a substrate such as polyester, polyethylene, polypropylene, paper, etc., which is coated with silicon, polyalkylene, or fluororesin. However, dimensional stability and smoothness can be used. From the viewpoint of peeling stability, a polyester film coated with silicon is particularly preferred.
Further, the thickness of the separator is preferably within a range of 10 to 100 μm, and more preferably within a range of 20 to 60 μm. If it is 10 μm or more, the film is not wrinkled by 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 float plate glass, heat ray absorbing plate glass, polished plate glass, mold plate glass, netted plate glass, lined plate glass, and colored glass such as green glass. The organic glass is a synthetic resin glass substituted for inorganic glass.
Examples of the organic glass (resin glazing) include a polycarbonate plate and a poly (meth) acrylic resin plate. Examples of the poly (meth) acrylic resin plate include a polymethyl (meth) acrylate plate.

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

<< Preparation of dispersion of vanadium dioxide fine particles >>
[Preparation of dispersion 1 of VO ₂ fine particles 1]
Single crystal fine particles of vanadium dioxide (VO ₂ ) to which tungsten (W) was added were produced. First, pure water 10 ml, ammonium vanadate _(NH 4 VO _3, manufactured by Wako Pure Chemical Industries, Ltd., special grade) and 0.433 g, ammonium tungstate para pentahydrate _{((NH 4) 10W 12 O} 41 · 5H 2 O , Wako Pure Chemical Industries, Ltd.) 0.00957 g was obtained. A 5% by mass aqueous solution of hydrazine hydrate (N ₂ H ₄ · H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., special grade) was slowly added dropwise to the resulting solution to prepare a solution having a pH value of 9.2. The prepared solution was put in a commercially available autoclave for hydrothermal reaction treatment (HU-25 type manufactured by Sanai Kagaku Co., Ltd.) (with a SUS body equipped with a 25 ml Teflon (registered trademark) inner cylinder) Hydrothermal reaction treatment was carried out for 24 hours at 270 ° C. for a time, and VO ₂ fine particles 1 were obtained.
The VO ₂ fine particles 1 had chromic properties, the number average primary particle size was 40 nm, and the ratio of tungsten (W) atoms to vanadium (V) atoms was 1.0%. The concentration of the finished VO ₂ fine particles 1 was 3.0% by mass, and this was used as dispersion 1 of VO ₂ fine particles 1.

[Preparation of dispersion 2 of VO ₂ fine particles 2]
0.433 g of ammonium vanadate (NH ₄ VO ₃ , manufactured by Wako Pure Chemical Industries, special grade) is mixed with 10 ml of pure water, and further hydrazine hydrate (N ₂ H ₄ · H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.). , Special grade) 5 mass% aqueous solution was slowly added dropwise to prepare a solution 1 having a pH value of 9.2. The prepared solution 1 is placed in a commercially available autoclave for hydrothermal reaction treatment (HU-25 type, manufactured by Sanai Kagaku Co., which is provided with a 25 ml volume Teflon (registered trademark) inner cylinder in a SUS body) at 100 ° C. Was subjected to a hydrothermal reaction treatment at 270 ° C. for 24 hours to obtain VO ₂ fine particles 2. The VO ₂ fine particles 2 had chromic properties, the number average primary particle size was 40 nm, and 99.5 atomic% or more of the metal component was vanadium. The concentration of the finished VO ₂ fine particles 2 was 3.0% by mass, and this was used as the dispersion 2 of VO ₂ fine particles 2.

<< Production of optical film >>
[Production of Optical Film 101 (Comparative Example)]
On a transparent base material of a polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, using an extrusion coater, the following coating solution 1 for forming an optical functional layer has a layer thickness after drying of 1 Wet application was performed under the condition of 0.5 μm, and then dried by blowing hot air at 110 ° C. for 2 minutes to form an optical functional layer containing VO ₂ , thereby producing an optical film 101.
(Optical functional layer forming coating solution 1)
Dispersion 1 of 3% by weight of VO ₂ fine particles 1 10 parts by weight Aqueous solution of 4% by weight of hydroxypropylmethylcellulose (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, manufactured by Sigma-Aldrich)
2 parts by mass Pure water 13 parts by mass

[Production of Optical Film 102 (Comparative Example)]
An optical film 102 was produced in the same manner as in the production of the optical film 101 except that the optical functional layer forming coating solution 1 was changed to the following optical functional layer forming coating solution 2.
(Optical functional layer forming coating solution 2)
Dispersion liquid 2 of 3% by mass of VO ₂ fine particles 2 10 parts by mass 4% by mass of hydroxypropylmethylcellulose (Metroose 60SH-50, manufactured by Shin-Etsu Chemical Co., Ltd.) aqueous solution
75 parts by weight 5% by weight surfactant aqueous solution (Triton X-100, manufactured by Sigma-Aldrich)
2 parts by mass Pure water 13 parts by mass

[Production of Optical Film 103 (Comparative Example)]
In the production of the optical film 102, the following colorant layer forming coating solution 1 was directly adjacent to the optical functional layer formed from the optical functional layer forming coating solution 2 using an extrusion coater at a film temperature of 23 ° C. Wet coating is carried out by adjusting the coating amount so that the average light absorptance at a light wavelength of 650 to 700 nm is 25%, followed by drying by blowing warm air at 90 ° C. for 2 minutes to form a colorant layer. Thus, an optical film 103 was produced.
(Colorant dispersion 1)
Copper phthalocyanine fine particles (Daiichi Seika Kogyo Co., Ltd., Blue No. 84, PB-15: 3, maximum absorption wavelength 630 nm, 720 nm) 1 part by mass, polymethyl methacrylate (VB-7103, manufactured by Mitsubishi Rayon Co.) methyl ethyl ketone 10 36 parts by mass of a mass% solution was dispersed with a super apex mill manufactured by Kotobukisha using zirconia beads until the average particle size was 30 nm, whereby Colorant Dispersion Liquid 1 was obtained.
(Colorant layer forming coating solution 1)
45 parts by weight of the colorant dispersion 1 and 30 parts by weight of methyl isobutyl ketone were mixed to obtain a coating liquid 1 for forming a colorant layer.

  [Production of Optical Films 104 to 110 (Invention) and Optical Film 111 (Comparative Example)) In production of the optical film 103, an average light absorption rate at a film temperature of 23 ° C. within a light wavelength range of 650 to 700 nm is 30. Optical films 104 to 111 were produced in the same manner except that the coating amount was adjusted to be 40%, 40%, 50%, 60%, 70%, 80%, 85%, and 90%.

[Production of Optical Film 112 (Invention)]
In the production of the optical film 102, the following coating solution 2 for forming a colorant layer is applied to the opposite surface of the optical functional layer formed from the coating solution 2 for forming an optical functional layer with a polyethylene terephthalate film interposed therebetween using an extrusion coater. The coating amount was adjusted so that the average light absorptance in the range of the light wavelength of 650 to 700 nm at a film temperature of 23 ° C. was 50%, wet coating was performed, and drying was performed at 90 ° C. for 1 minute. Next, using an ultraviolet lamp, the coating film is 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, and coloring that also serves as a hard coat layer The agent layer was formed, and the optical film 112 was produced.
(Colorant layer forming coating solution 2)
Colorant dispersion 1 315 parts by mass Aronix (registered trademark) M-305 (3, 4 functional acrylate, 3 functional component 60% by mass, manufactured by Toagosei Co., Ltd.)
196 parts by mass EBECRYL (registered trademark) 350 (bifunctional silicon acrylate, manufactured by Daicel Ornex Co., Ltd.) MIBK (methyl isobutyl ketone) diluent (1% by mass)
18 parts by weight hexoate cobalt 8% (metal soap, manufactured by Toei Chemical Co., Ltd.) 3 parts by weight Irgacure (registered trademark) 184 (photopolymerization initiator, manufactured by BASF Corporation)
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

[Production of Optical Film 113 (Invention)]
(Preparation of dispersion 3 of VO ₂ fine particles 2)
An ultrafiltration apparatus having a filtration membrane made of polyethersulfone and having a molecular weight cut off of 300,000, which is circulated in the system while maintaining a dispersion 2 of 3% by mass of VO ₂ fine particles 2 at 20 ° C. When the volume of the dispersion 2 of the initial VO ₂ fine particles 2 is set to 100%, concentration is performed using the solvent displacement treatment apparatus shown in FIG. After concentrating to 100% by volume, ethyl alcohol was added. Next, after the dispersion was concentrated again to 20% by volume, methylene chloride was added as a solvent to make 100% by volume. Further, after the dispersion was concentrated to 20% by volume, methylene chloride was added as a solvent. 100% by volume was subjected to solvent replacement treatment three times to prepare a dispersion 3 of solvent-based VO ₂ fine particles 2 having a particle concentration of 3% by mass, and filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. .
(Preparation of dope)
The following methylene chloride was added to the pressure dissolution tank. A dispersion 3 of the cycloolefin polymer (abbreviation: COP) and the VO ₂ fine particles 2 prepared above was added to a pressurized dissolution tank containing an organic solvent while stirring. While this was heated and stirred, the cycloolefin polymer was dissolved, and this was added to Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. The dope was prepared by filtration using 244.
<Dope composition>
192 parts by mass of methylene chloride Hydrophobic polymer resin: cycloolefin polymer (trade name: Arton, manufactured by JSR Corporation)
76.9 parts by mass 3% by mass of VO ₂ fine particle 2 dispersion 3 12.0 parts by mass (film formation)
Using the dope prepared above, according to the solution casting film forming method which is described in and JP 2014-159082 Patent JP 2014-095729, the optical functional layer and the transparent substrate 1 containing VO ₂ microparticles Produced.
An optical film 113 was produced by forming a colorant layer on one side of the optical functional layer / transparent substrate 1 containing VO ₂ fine particles in the same manner as the production of the optical film 106.

[Production of Optical Film 114 (Invention)]
On a transparent substrate of a polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, the following coating solution 1 for forming a colorant layer and an optical functional layer was applied at a film temperature of 23 ° C. using an extrusion coater. The wet coating is performed by adjusting the coating amount so that the average light absorptance in the light wavelength range of 650 to 700 nm is 50%, followed by drying by blowing warm air of 90 ° C. for 2 minutes, and then coloring agent An optical film 114 was produced by forming a layer / optical functional layer.
(Preparation of dispersion 4 of VO ₂ fine particles 2)
An ultrafiltration apparatus having a filtration membrane made of polyethersulfone and having a molecular weight cut off of 300,000, which is circulated in the system while maintaining a dispersion 2 of 3% by mass of VO ₂ fine particles 2 at 20 ° C. Concentration operation is performed using the solvent substitution processing apparatus shown in FIG. 2 equipped with a Pericon 2 cassette manufactured by Nihon Millipore Co., Ltd., up to 20% by volume when the initial volume of dispersion of VO ₂ fine particles 2 is 100%. After concentration, ethyl alcohol was added to 100% by volume. Next, this dispersion was concentrated again to 20% by volume, and then methyl ethyl ketone was added as a solvent to make 100% by volume, and the solvent substitution treatment was performed twice, so that the solvent concentration of VO ₂ fine particles 2 having a particle concentration of 3% by mass was obtained. A dispersion 4 was prepared.
(Coating liquid 1 for forming colorant layer and optical functional layer)
Colorant dispersion liquid 1 37 parts by mass Dispersion liquid 4 of VO ₂ fine particles 2 33 parts by mass was mixed to prepare a coating liquid 1 for forming a colorant layer / optical function layer.

[Production of Optical Film 115 (Invention)]
An optical film 115 was prepared in the same manner as in the production of the optical film 106 except that the dispersion time of the colorant dispersion 1 was changed so that the average particle diameter of the particles was 60 nm.

[Production of Optical Film 116 (Invention)]
In the production of the optical film 106, C.I. I. An optical film 116 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).

[Production of Optical Film 117 (Invention)]
In the production of the optical film 106, the colorant dispersion 1 was changed to YMF-02A (18% by mass Cs _0.33 WO ₃ dispersion, 10% by mass dispersant, average particle size 50 nm, methyl isobutyl ketone solvent, Sumitomo Metal Mining Co., Ltd. The optical film 117 was produced in the same manner except that the absorption wavelength peak was changed over a wide range of 880 to 2200 nm.

[Production of Optical Film 118 (Invention)]
In the preparation of optical films 106, to produce an optical film 118 except for changing the dispersion 2 of VO ₂ fine particles 2 to the dispersion 1 of VO ₂ microparticles 1 in the same manner.

[Production of Optical Films 119 to 122 (Invention)]
In the production of the optical film 102, the colorant layer / adhesive layer forming coating solution 1 described below is directly adjacent to the optical functional layer formed from the optical functional layer forming coating solution 2, using an extrusion coater. Wet application was carried out by adjusting the coating amount so that the average light absorptance in the light wavelength range of 650 to 700 nm at 23 ° C. was 40%, 50%, 70% and 80%, respectively, followed by a temperature of 90 ° C. Air was blown for 2 minutes to dry to form a colorant layer also serving as an adhesive layer, and optical films 119 to 122 were produced.
(Colorant dispersion 2)
Methyl ethyl ketone of copper phthalocyanine fine particles (Daiichi Seika Kogyo Co., Ltd., cyanine blue 4933GN-EP, PB-15: 4, maximum absorption wavelength 640 nm, 740 nm), polymethyl methacrylate (VB-7103, manufactured by Mitsubishi Rayon Co., Ltd.) 36 parts by mass of a 10% by mass dissolving solution was dispersed with a super apex mill manufactured by Kotobukisha using zirconia beads until the number average primary particle size became 30 nm to obtain a colorant dispersion 2.
(Colorant layer / adhesive layer forming coating solution 1)
78 parts by mass of 2-ethylhexyl methacrylate, 12 parts by mass of butyl acrylate, 7 parts by mass of 2-hydroxyethyl acrylate and 3 parts by mass of acrylic acid are dissolved in toluene (solid content concentration: 33% by mass), and a polymerization initiator. Using benzoyl peroxide (5% by mass with respect to the monomer) as a radical polymerization at 83 ° C. for 240 minutes, a polymer solution having a solid content concentration of 33% by mass (weight average molecular weight 550,000) was obtained. To 100 parts by mass of the obtained polymer solution, 0.5 parts by mass of titanium chelate (Orgatechs TC-401: Matsumoto Fine Chemical Co., Ltd.) and 3 parts by mass of a UV absorber (Tinuvin 477, manufactured by Ciba-Gigi Co., Ltd.) are added. 37 parts by mass of the colorant dispersion 2 was added to prepare a coating liquid 1 for forming a colorant layer / adhesive layer.

[Production of Optical Film 123 (Invention)]
In the production of the optical film 102, the following colorant layer forming coating solution 2 was directly adjacent to the optical function layer formed from the optical function layer forming coating solution 2 using an extrusion coater at a film temperature of 23 ° C. The colorant layer is prepared by adjusting the coating amount so that the average light absorptivity in the light wavelength range of 650 to 700 nm is 50%, performing wet coating, and then spraying with 90 ° C. warm air for 2 minutes to dry. To form an optical film 124.
(Colorant layer forming coating solution 2)
1 part by mass of copper phthalocyanine fine particles (Daiichi Seika Kogyo Co., Ltd., Blue No. 84, PB-15: 3, maximum absorption wavelength 630 nm, 720 nm), 1 part by mass of Chromophthal Pink PT (CI Pigment Red 122, manufactured by BASF), Disperse 36 parts by mass of a 10% by weight methyl ethyl ketone solution of polymethyl methacrylate (VB-7103, manufactured by Mitsubishi Rayon Co., Ltd.) using a super apex mill manufactured by Kotobukisha using zirconia beads until the number average primary particle size becomes 30 nm. A coating solution 2 for forming a colorant layer was obtained.

The spectral transmittance of the produced optical film 116 at an optical wavelength of 1300 nm was less than 50% at a film temperature of 23 ° C., and the other optical films were 50% or more.
Moreover, since the produced optical film 123 used together with a pigment that absorbs green, the spectral transmittance at a light wavelength of 550 nm is in the range of 30 to 60% at a film temperature of 23 ° C. there were. Other optical films were out of the range of 30 to 60%.

<Evaluation>
The size of a glass plate of 1.3 mm in thickness (manufactured by Matsunami Glass Industry Co., Ltd., “slide glass white edge polishing”) is 15 cm × 20 cm, and the optical films 119 to 122 are connected to other layers through a colorant layer also serving as an adhesive layer. The optical film was bonded using a transparent adhesive sheet (manufactured by Nitto Denko Corporation, LUCIACS CS9621T).

(Evaluation of heat insulation in summer)
In an environment chamber adjusted to 28 ° C., a 150 W halogen lamp was turned on from a position 20 cm away from the opposite side of the glass film on which the optical film was bonded. Another set of the same equipment was prepared, and a glass without a film was set as a comparison. After 15 minutes, the heat shielding property was evaluated by holding the hand in the vicinity of 30 cm on the opposite side of the lamp across the glass.
○: There is a strong heat-shielding effect △: There is a heat-shielding effect, but there is also a feeling of crease ×: There is a strong crease-feel, not much different from without film

(Evaluation of heat insulation in the spring)
In an environment chamber adjusted to 23 ° C., a 150 W halogen lamp was turned on from a position 30 cm away from the opposite side of the glass film on which the optical film was bonded. Another set of the same equipment was prepared, and a glass without a film was set as a comparison. After 15 minutes, the heat shielding property was evaluated by holding the hand in the vicinity of 30 cm on the opposite side of the lamp across the glass.
○: No crease sensation △: Weak crease sensation ×: There is a crease sensation, not much different from no film

(Evaluation of heat permeability in winter)
In an environmental chamber adjusted to 20 ° C., a 50 W halogen lamp was turned on from a position 20 cm away from the opposite side of the glass film on which the optical film was bonded. After 15 minutes, a hand was placed near 30 cm on the opposite side of the lamp across the glass, and compared with a place where the lamp was not hit.
○: The warmth of the lamp is felt Δ: The warmth of the lamp is felt a little ×: Not much different from the place without the lamp

The terms shown in Table 1 are as follows.
Copper Pc-A: Copper phthalocyanine fine particles (Daiichi Seika Kogyo Co., Ltd., Blue No. 84, PB-15: 3, maximum absorption wavelengths 630 nm, 720 nm)
Copper Pc-B: Copper phthalocyanine fine particles (manufactured by Dainichi Seika Kogyo Co., Ltd., cyanine blue 4933GN-EP, PB-15: 4, maximum absorption wavelengths 640 nm, 740 nm)
CI solvent: C.I. I. Solvent Blue 63 (1-methylamino-4-[(3-methylphenyl) amino] -9,10-anthraquinone, maximum absorption wavelength 645 nm)
Green pigment: Cromophtal Pink PT (CI Pigment Red 122, manufactured by BASF)
CWO: Cs _0.33 WO ₃

  From the results shown in Table 1, the optical film of the present invention is better than the optical film of the comparative example in terms of heat insulation for summer, heat for spring, and heat for winter. It is recognized that

  As described above, the present invention controls the transition and fully exhibits the effect of thermodynamics without losing the large change width of the near-infrared light shielding rate and transmittance before and after the transition of vanadium dioxide. In addition, it is suitable for providing an optical film that can exhibit heat-shielding properties when the feeling of galling is strong even at low temperatures.

DESCRIPTION OF SYMBOLS 1 Optical film 2, 2g Transparent base material 3, 3d, 3g Optical functional layer 4, 4a, 4f Hard coat layer 5, 5b Adhesive layer 6 Colorant layer 7 Glass 10 Solvent substitution processing apparatus 11 Preparation kettle 12 Vanadium dioxide microparticles are included Dispersion 13 Circulation line 14 Circulation pump 15 Ultrafiltration unit 16 Discharge port 17 Solvent stock kettle 18 Solvent 19 Solvent supply line

Claims (10)

An optical film containing vanadium dioxide fine particles having thermochromic properties,
Containing a dye or pigment that absorbs light in the light wavelength range of 650-700 nm, and
The optical film having an average light absorptance of the optical film in the light wavelength range of 30 to 85% at 23 ° C.   2. The optical device according to claim 1, wherein the dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is a dye or pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm. the film.   The dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is a pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm. Optical film.   The optical film according to claim 3, wherein the pigment having a maximum absorption wavelength in the light wavelength range of 600 to 750 nm is a metal phthalocyanine pigment.   5. The optical according to claim 1, wherein the number average primary particle size of pigment particles constituting the pigment is smaller than the number average primary particle size of the vanadium dioxide fine particles. the film.   The dye or pigment that absorbs light in the light wavelength range of 650 to 700 nm is contained in the same layer as the layer containing the vanadium dioxide fine particles or in an adjacent layer in direct contact with the layer containing the vanadium dioxide fine particles. The optical film according to any one of claims 1 to 5, wherein the optical film is provided.   The optical film according to any one of claims 1 to 6, wherein 99.5 atomic% or more of the metal component of the vanadium dioxide fine particles is vanadium.   8. The optical film according to claim 1, wherein a spectral transmittance of the optical film at a light wavelength of 1300 nm is 50% or more at 23 ° C. 9.   9. The optical film according to claim 1, wherein an average optical absorptance of the optical film within a light wavelength range of 650 to 700 nm is within a range of 50 to 70% at 23 ° C. 9. The optical film described in 1.   10. The optical film according to claim 1, wherein a spectral transmittance of the optical film at a light wavelength of 550 nm is within a range of 30 to 60% at 23 ° C. 10.

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