JP6465117B2 - Manufacturing method of optical film - Google Patents

Description

  The present invention relates to an optical film for shielding near infrared light and a method for producing the same. More specifically, an optical film having thermochromic properties, low haze, excellent storage stability in a high-humidity environment, and a large rate of change in infrared transmission effect and infrared shielding effect during temperature changes, and a method for producing the same About.

  In recent years, in automobiles and buildings, etc., glass that has high heat insulation or heat insulation properties and films that are bonded to glass have been circulated in the market to block the heat rays felt by human skin due to the influence of external light (sunlight) entering through windows. ing. Recently, with the widespread use of electric vehicles and the like, development of near-infrared light (heat ray) shielding films applied to glass has been actively conducted from the viewpoint of increasing the cooling efficiency in the vehicle.

  The near-infrared light shielding film can be applied to a vehicle body or a window glass of a building to reduce a load on a cooling facility such as an air conditioner in the vehicle, and is an effective means for energy saving.

  As such a near-infrared shielding film, an optical film containing a conductor such as ITO (tin-doped indium oxide) as an infrared absorbing substance is disclosed. Japanese Unexamined Patent Application Publication No. 2010-222233 discloses a near-infrared light shielding film including a functional plastic film having an infrared reflection layer and an infrared absorption layer.

  On the other hand, it has a reflective layer stack in which a large number of low refractive index layers and high refractive index layers are alternately stacked, and selectively reflects near infrared light by adjusting the thickness of each refractive index layer. A near-infrared light shielding film has been proposed (see, for example, Patent Document 1).

  The near-infrared light shielding film having such a configuration exhibits a favorable effect due to its high near-infrared light shielding effect in a low-latitude zone near the equator where the illuminance of sunlight is high. However, during the winter period of mid-latitude to high-latitude zones, on the contrary, when sunlight is taken into the car or the room as much as possible to keep the room temperature, the incident light is uniformly shielded. There is a problem that the room does not warm up.

Based on the above problems, a method of applying a thermochromic material capable of controlling the optical properties of near-infrared light shielding and transmission by temperature is being studied for near-infrared light shielding films. A typical material is vanadium dioxide (hereinafter referred to as VO ₂ ). VO ₂ is known to cause a phase transition in a temperature range of around 68 ° C. and exhibit thermochromic properties.

That is, 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 in a low-temperature environment. . As a result, near-infrared light is shielded in the hot summer season to suppress the indoor temperature rise, and external light energy can be taken in in the cold winter season.

As a specific example of VO ₂ having such characteristics, a method of obtaining vanadium dioxide (VO ₂ ) nanoparticles by a hydrothermal synthesis method using a vanadium compound and hydrazine or a hydrate thereof is disclosed. (For example, refer to Patent Document 2). Also, to disperse the VO ₂ nanoparticles prepared by the hydrothermal synthesis method in a transparent resin, by a laminated body forming the VO ₂ dispersed resin layer on a resin substrate, a method of providing a thermochromic film (For example, refer to Patent Document 3).

However, when the VO ₂ -containing fine particles are filtered and dried after the formation of the particles, it has been found that the primary particles of the VO ₂ -containing fine particles are aggregated in the process, so that massive secondary particles are likely to be formed. In particular, the secondary particles of VO ₂ -containing fine particles once prepared through a drying step are difficult to be agglomerated and become primary particles even after a general dispersion treatment, and it is difficult to form primary particles. In the functional film, it exists as secondary particles in an aggregated state. It has been found that the presence of such secondary particles in the optical functional film reduces the difference between infrared transmittance at low temperatures and infrared shielding properties at high temperatures.

  Furthermore, it has been found that when a water-based binder is used for the optical functional film, the difference between the infrared transmittance at low temperature and the infrared shielding property at high temperature becomes small when stored for a long time under high humidity.

  The development of an optical film that overcomes the various problems of the thermochromic film as described above, has thermochromic properties, and has a large change in the infrared transmission effect and the infrared shielding effect when the temperature changes is eagerly desired.

International Publication No. 2013/065679 JP2011-178825A JP2013-184091A

The present invention has been made in view of the above-mentioned problems, and its problem is that it has a thermochromic property capable of adjusting the near-infrared shielding rate according to the temperature conditions of the environment to be used, has a low haze, and a high humidity environment. excellent storage stability under, and is that the rate of change of the infrared transmission effect and infrared shielding effect during temperature changes to provide a method for manufacturing a large optical fill beam.

As a result of intensive studies in view of the above problems, the present inventor has made vanadium dioxide-containing fine particles (hereinafter also referred to as VO ₂ -containing fine particles) in which the number average particle size of all particles including primary particles and secondary particles is 200 nm or less. .) And an optical film having an optical functional layer containing a hydrophobic binder resin, and has a thermochromic property capable of adjusting the near-infrared shielding rate according to the temperature condition of the environment to be used. The present inventors have found that an optical film that is low and excellent in storage stability in a high-humidity environment and that has a large rate of change in infrared transmission effect and infrared shielding effect when temperature changes can be obtained.

  That is, the said subject of this invention is solved by the following means.

1 . A method for producing an optical film comprising a step of forming an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin,
The number average particle size of all particles including the primary particles and secondary particles of the vanadium dioxide-containing fine particles is adjusted to be 200 nm or less,
The vanadium dioxide-containing fine particles, was prepared as an aqueous dispersion containing a vanadium dioxide-containing microparticles prepared by the water-based synthesis, the aqueous dispersion, the vanadium dioxide-containing particulates without going through the dry state, the solvent replacement step the method of manufacturing an optical optical film you comprises preparing a solvent dispersion containing vanadium dioxide-containing fine particles by.
2. 2. The method for producing an optical film according to item 1, wherein the hydrophobic binder resin is a resin polymerized in a curing process using a hydrophobic polymer or a monomer of a hydrophobic binder resin.

3 . The solvent replacement step is composed of a concentration step of a dispersion containing vanadium dioxide-containing fine particles and a solvent dilution step of adding a solvent to the concentrate obtained in the concentration step, and a processing operation in the concentration step and the solvent dilution step. The method for producing an optical film as described in item 1 or 2 , wherein the method is a step of preparing a solvent dispersion containing vanadium dioxide-containing fine particles by repeating 2 or more times.

4 . 4. The method for producing an optical film according to claim 3 , wherein the concentration means used in the step of concentrating the dispersion containing the vanadium dioxide-containing fine particles is an ultrafiltration method.

5 . Any one of Items 1 to 4, wherein the solvent dispersion liquid containing vanadium dioxide-containing fine particles prepared by the solvent substitution step contains water in a range of 0.01 to 30% by mass. The method for producing an optical film according to claim 1.

6 . An optical functional layer forming coating solution containing a solvent dispersion containing vanadium dioxide-containing fine particles prepared by the solvent substitution step and a hydrophobic binder is prepared, and the optical functional layer forming coating solution is applied onto a transparent substrate. the method for producing an optical film according to any one of the first term to the fifth term, characterized in that dried to form an optical function layer.

7 . An optical functional layer-forming dope comprising a solvent dispersion containing vanadium dioxide-containing fine particles prepared by the solvent substitution step and a hydrophobic binder is prepared, and the optical functional layer-forming dope is optically layered by a solution casting method. the method for producing an optical film according to any one of the first term and forming to paragraph 6 of.

8 . In addition to the optical functional layer, either from the first term, and forming a near-infrared light-shielding layer having a function to shield at least a portion of the light wavelength range of 700~1000nm to paragraph 7 The manufacturing method of the optical film of one term.

  By the above means of the present invention, it has thermochromic properties that can adjust the near-infrared shielding rate according to the temperature environment, has low haze, excellent storage stability in a high humidity environment, and transmits infrared rays when temperature changes An optical film having a large rate of change between the effect and the infrared shielding effect and a method for producing the same can be provided.

  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.

Conventionally, as a method for preparing VO ₂ -containing fine particles, there are a method of pulverizing a VO ₂ crystal mass synthesized by a baking treatment and a method of obtaining a VO ₂ dispersion by an aqueous synthesis method. In the method of pulverizing the VO ₂ crystal mass, it is difficult to make fine particles to a size of 100 nm or less as the number average particle diameter, and the primary particle diameter of the VO ₂ particles is large. Also, in the pulverization method, due to the energy at the time of pulverization, some particles are strongly agglomerated secondary particles, and usually such secondary particles are completely converted into primary particles even by dispersion treatment. It was difficult to obtain a film having a number average particle size greatly exceeding 200 nm even in the optical functional layer.

Examples of the aqueous synthesis method for preparing VO ₂ -containing fine particles in an aqueous system include a synthesis method using a hydrothermal method. According to the hydrothermal synthesis method, fine particles having a number average particle diameter of 100 nm or less can be synthesized as the primary particle diameter.

However, in the conventional method, when the VO ₂ -containing fine particles synthesized by the water-based synthesis method are mixed with the binder resin to form the optical functional layer, the synthesized VO ₂ -containing fine particles are once dried and then the solvent-based binder resin And a solvent are mixed to prepare a coating solution, which is used to form an optical functional layer. However, with this method, it has been found that VO ₂ -containing fine particles can exist only in a particle dispersion state in which secondary aggregation has occurred in the layer with a number average particle size exceeding 200 nm. This is because it has been found that the VO ₂ -containing fine particles are subjected to a drying step, whereby the surface of the water-based synthesized VO ₂ -containing fine particles becomes hydrophilic and has high surface energy, resulting in strongly agglomerated secondary particles. It was. Even if the secondary particles thus formed were subjected to a normal dispersion treatment, it was difficult to redisperse the number average particle size to a level of 200 nm or less.

  In the present invention, vanadium dioxide-containing fine particles are prepared by an aqueous synthesis method, and the prepared vanadium dioxide-containing fine particles are prepared as a solvent dispersion containing vanadium dioxide-containing fine particles by a solvent replacement step without passing through a dry state. As a result, it was possible to obtain a vanadium dioxide-containing fine particle dispersion in which the number average particle diameter of all the particles including the primary particles and the secondary particles is 200 nm or less.

  By forming an optical functional layer using a vanadium dioxide-containing fine particle dispersion liquid in which the number average particle diameter of all particles including primary particles and secondary particles prepared in this way is 200 nm or less, and a hydrophobic binder resin. When the temperature of the usage environment changes, the optical film has a large change in infrared transmission and infrared shielding. This is because the crystals constituting the surface of the vanadium dioxide-containing fine particles are more likely to undergo transition due to temperature changes than the internal structure. Therefore, the optical functional layer containing vanadium dioxide-containing fine particles has an infrared transmission property due to environmental temperature changes. And the change of the infrared shielding rate becomes large. By setting the number average particle diameter of the vanadium dioxide-containing fine particles to 200 nm or less, the area ratio of the particle surface is increased. On the other hand, since the surface area ratio of the particles having a primary particle size exceeding 200 nm decreases, secondary aggregation occurs even when the primary particle size is 200 nm or less, and the number average particle size is more than 200 nm. In the case of agglomeration, it is speculated that the interaction between the surfaces of the primary particles becomes stronger, and the change width of the infrared transmittance and the infrared shielding rate at the time of temperature change is reduced.

  On the other hand, when a hydrophilic binder is used, it has been found that when exposed to a long period of time in a high humidity environment, a phenomenon occurs in which the change width of the infrared transmittance and the infrared shielding rate when the temperature changes is reduced. This phenomenon is speculated that the surface of vanadium dioxide-containing fine particles may be altered by moisture. For such problems, the use of a hydrophobic binder can suppress the above-described deterioration caused by moisture, and as a result, the change width between the infrared transmittance and the infrared shielding rate when the temperature changes can be maintained. I think that.

  Moreover, by preparing the vanadium dioxide-containing fine particles by an aqueous synthesis method, the range of change between the infrared transmittance and the infrared shielding rate when the temperature changes is further increased. Fine crystals are easily formed by the aqueous synthesis method, and the vanadium dioxide-containing fine particles prepared by the aqueous synthesis method have vanadium dioxide synthesized by a method other than the aqueous synthesis method such as a firing method in a reducing environment as the particle surface characteristics. It is easier to transfer on the particle surface than the contained fine particles, and therefore, it is thought that the change width of the light transmittance due to the environmental change is increased.

  In a dispersion containing vanadium dioxide-containing fine particles, if the water content in the dispersion exceeds 30% by mass, the vanadium dioxide-containing fine particles are likely to be oxidized due to the high water concentration, and the film forming ability by the coexisting hydrophobic binder Decreases and haze increases. Moreover, when it becomes less than 0.01 mass%, the change width of the infrared rays transmittance | permeability at the time of a temperature change and an infrared shielding factor will become small. By leaving moisture in a specific range in the dispersion containing vanadium dioxide-containing fine particles, the specific range of water is adsorbed on the particle surface, and the surface characteristics of particles prepared by the aqueous synthesis method are easily transferred. However, if the content is less than 0.01%, it is thought that the particle surface may be altered.

  In addition, since the hydrophobic binder does not act on the particle surface as strongly as the solvent in the optical functional layer, it is considered that the change width does not decrease even if the solvent or moisture dries at the time of layer formation.

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 an example of the layer arrangement of the optical film having the near infrared light shielding layer of the present invention Schematic sectional view showing another example of the layer arrangement of the optical film having the near infrared light shielding layer of the present invention Schematic sectional view showing another example of the layer arrangement of the optical film having the near infrared light shielding layer of the present invention Schematic configuration diagram showing an example of a solvent replacement processing apparatus applicable to the present invention

The method for producing an optical film of the present invention is a manufacturing method of an optical film having a step of forming an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin, primary particles prior Symbol vanadium dioxide particles And the number average particle size of all particles including secondary particles was adjusted to be 200 nm or less, and prepared as an aqueous dispersion containing vanadium dioxide-containing fine particles prepared by an aqueous synthesis method as the vanadium dioxide-containing fine particles. Thereafter, the aqueous dispersion is prepared as a solvent dispersion containing vanadium dioxide-containing fine particles by a solvent substitution step without the vanadium dioxide-containing fine particles being dried . This feature is a technical feature common to the claimed invention.

  As an embodiment of the present invention, from the viewpoint that the effect of the present invention can be further expressed, the primary particle number ratio of the vanadium dioxide-containing fine particles in the optical functional layer is 30% by number or more of the total number of particles. It is preferable from the standpoint that it is possible to obtain more excellent storage stability in a high-humidity environment and a high rate of change in infrared transmission effect and infrared shielding effect during temperature changes.

  Moreover, it is a more preferable aspect that the optical functional layer according to the present invention is formed on a transparent substrate, or that the optical functional layer has a structure that also functions as a resin substrate.

  In addition to the optical functional layer, having a near-infrared light shielding layer having a function of shielding at least a part of the light wavelength range of 700 to 1000 nm is in addition to the near-infrared heat shielding effect by the vanadium dioxide-containing fine particles. Thus, the light reflection effect by the reflective layer laminate can be provided, and a higher near-infrared shielding effect can be obtained.

  The method for producing an optical film of the present invention is a method for producing an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin, wherein the primary particles and secondary particles of the vanadium dioxide-containing fine particles are produced. The number average particle diameter of all the particles including the particles is adjusted to be 200 nm or less.

  The vanadium dioxide-containing fine particles are vanadium dioxide-containing fine particles prepared by an aqueous synthesis method, and more effectively, the vanadium dioxide having a number average particle diameter of 200 nm or less of all the particles including the primary particles and the secondary particles. It is preferable from the viewpoint that the contained fine particles can be stably prepared and the object and effects of the present invention can be more realized.

  In addition, the hydrophobic binder resin is a resin obtained by polymerizing in a curing process using a hydrophobic polymer or a monomer of a hydrophobic binder resin, so that an optical functional layer can be stably formed. To preferred.

In the method for producing an optical film of the present invention, the vanadium dioxide-containing fine particles are prepared as an aqueous dispersion containing vanadium dioxide-containing fine particles by an aqueous synthesis method, and then the aqueous dispersion is used. without undergoing, characterized by preparing as a solvent dispersion containing vanadium dioxide-containing fine particles by solvent substitution process, the vanadium dioxide-containing fine particles a number-average particle size of less 200nm of all particles, including primary particles and secondary particles Ru can be stably prepare a dispersion containing.

  Further, the solvent replacement step is composed of a concentration step for concentrating the dispersion liquid containing vanadium dioxide-containing fine particles, and a solvent dilution step for adding the solvent to the concentrate to dilute, and processing operations in the concentration step and the solvent dilution step are performed. It is a process of preparing a solvent dispersion containing vanadium dioxide-containing fine particles by repeating twice or more, or that the concentration means used in the concentration process is an ultrafiltration method to ensure that the water content is within a specific range. From the viewpoint of being able to prepare a solvent-based dispersion liquid controlled to a constant value.

  In addition, the dispersion containing vanadium dioxide-containing fine particles contains water in a range of 0.01 to 30% by mass, so that the rate of change of the infrared transmission effect and the infrared shielding effect when the temperature changes stably. It is preferable from the viewpoint that a large optical film can be produced.

  Moreover, a coating liquid for forming an optical functional layer containing a solvent dispersion containing vanadium dioxide-containing fine particles prepared by a solvent substitution step and a hydrophobic binder is prepared, and the coating liquid for forming an optical functional layer is applied on a transparent substrate. , A method of drying to form an optical functional layer, or a dope for forming an optical functional layer comprising a solvent dispersion containing vanadium dioxide-containing fine particles prepared by a solvent substitution step and a hydrophobic binder, and the optical functional layer A method of forming an optical functional layer formed by forming a dope for forming by a solution casting method has a thermochromic property capable of adjusting the near-infrared shielding rate according to the temperature environment, and has a low haze and a high humidity environment. It is preferable from the viewpoint of obtaining an optical film that is excellent in preservability and has a high rate of change in infrared transmission effect and infrared shielding effect when temperature changes.

  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.

<< Summary of optical film layer structure >>
The optical film according to the present invention has an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin, and includes all particles including primary particles and secondary particles of the vanadium dioxide-containing fine particles in the optical functional layer. The number average particle size of is preferably 200 nm or less.

  A typical configuration example of the optical film of the present invention will be described with reference to the drawings.

  One of the preferable embodiments of the optical film of the present invention is a configuration in which the optical functional layer according to the present invention is formed on a transparent substrate.

  FIG. 1 is a schematic cross-sectional view showing an example of a basic configuration of an optical film having an optical functional layer which is a first embodiment containing vanadium dioxide-containing fine particles and a hydrophobic binder resin defined in the present invention.

An optical film 1 shown in FIG. 1 has a configuration in which an optical functional layer 3 is laminated on a transparent substrate 2. The optical functional layer 3 of the first embodiment is present in a state where vanadium dioxide-containing fine particles are dispersed in the hydrophobic binder resin B1. The vanadium dioxide-containing fine particles, constitutes the primary particles VO _S of vanadium dioxide vanadium-containing particles dioxide are present independently, an aggregate of two or more vanadium-containing microparticles dioxide (also referred to as aggregates) there, there is a secondary particle VO _M of vanadium dioxide. In the present invention, an aggregate of two or more vanadium dioxide-containing fine particles is collectively referred to as secondary particles, and is also referred to as secondary particle aggregates or secondary aggregate particles.

In the present invention, the number average particle size by all particles, including primary particles V0 _S and secondary particles VO _M of vanadium dioxide-containing fine particles in the optical functional layer 3, characterized in that at 200nm or less.

  In the present invention, the average particle size of the vanadium dioxide-containing 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 expose a cross section as shown in FIG. Next, the exposed cross section is photographed at 10,000 to 100,000 times using a transmission electron microscope (TEM). The particle size of all the vanadium dioxide-containing fine particles present in a certain region of the photographed cross section is measured. At this time, the vanadium dioxide-containing fine particles to be measured are preferably in the range of 50 to 100 particles. The shot particles are included a primary particle VO _S is a single particle, as shown in FIG. 1, the secondary particle VO _M is a more aggregate 2 particles.

The particle size measurement of each particle, the particle size of the primary particles VO _S vanadium dioxide, measuring the diameter of particles in the state of being independently apart from. 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. On the other hand, for vanadium dioxide in which two or more particles are aggregated, the projected area of the entire aggregate is obtained, and then the projected area is converted into a circle, and the diameter is taken as the particle size. The number average diameter is obtained for each diameter of the primary particles and secondary particles obtained as described above. Since the cut-out cross-sectional portion has a variation in particle distribution, such measurement is performed for 10 different cross-sectional areas, the total number of particles is measured from 500 to 1000, and the total number average diameter is obtained. Is the “number average particle size (nm) of all particles including primary and secondary particles of vanadium dioxide-containing fine particles” in the present invention.

  Although details of the vanadium dioxide-containing fine particles according to the present invention will be described later, the primary particle diameter is preferably in the range of 10 to 100 nm. Accordingly, the particle size of the secondary particles varies depending on the number of aggregated particles, but is roughly in the range of 50 to 500 nm.

  In the optical film of the present invention, in addition to the optical functional layer containing the vanadium dioxide-containing fine particles and the hydrophobic binder resin according to the present invention, the function of shielding at least part of the light wavelength range of 700 to 1000 nm. It is preferable to have a near-infrared light shielding layer having

  Another preferred embodiment of the optical film of the present invention is a hybrid structure in which the optical functional layer also functions as a resin base material.

  FIG. 2 is a schematic cross-sectional view showing another example of the basic configuration of the optical film of the present invention. The transparent substrate 2 and the optical functional layer 3 as shown in FIG. This is a hybrid optical functional layer (2 + 3) which is a second embodiment composed of one layer.

Using a polymer constituting the transparent substrate as a hydrophobic binder resin B2, into the hydrophobic binder resin B2, and the primary particles VO _S of vanadium dioxide vanadium-containing particles dioxide are present independently, two more are secondary particles VO _M of vanadium dioxide-containing fine particles dispersed is formed to have constituting the optical functional layer having both a transparent substrate functions as a single layer.

  FIGS. 3A to 3C are optical films having the configuration shown in FIG. 1 and having a near infrared light shielding layer together with the optical functional layer 3 according to the first embodiment of the present invention on a transparent substrate. It is a schematic sectional drawing which shows a typical layer arrangement example.

  The optical film 1 shown in FIG. 3A has a configuration in which the optical functional layer 3, the near-infrared light shielding layer 4, and the transparent substrate 2 are arranged in this order from the light incident side L.

  The optical film 1 shown in FIG. 3B is an example in which the optical functional layer 3 according to the present invention is disposed between the transparent substrate 2 and the near-infrared light shielding layer 4, and FIG. In this example, the near-infrared light shielding layer 4 is disposed on the light incident side L, and the optical functional layer 3 according to the present invention is disposed on the back surface side of the transparent substrate 2.

  As an optical film of this invention, you may provide various functional layers as needed other than each structure layer demonstrated above.

  The total film thickness of the optical film of the present invention is not particularly limited, but is generally within the range of 10 to 1500 μm, preferably within the range of 20 to 1000 μm, and more preferably within the range of 30 to 500 μm. Especially preferably, it exists in the range of 40-300 micrometers.

  As the optical characteristics of the optical film of the present invention, the visible light transmittance measured by a method according to JIS R 3106 (1998) is preferably 30% or more, more preferably 50% or more, and still more preferably. Is 60% or more.

<Each film material>
The optical film of the present invention has an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin, and the number of all particles including primary particles and secondary particles of vanadium dioxide-containing fine particles in the optical functional layer. The average particle size is 200 nm or less.

  Furthermore, it is preferable to have a near-infrared light shielding layer having a function of shielding at least part of the light wavelength range of 700 to 1000 nm.

  Hereinafter, details of the optical functional layer, which is a constituent element of the optical film of the present invention, a resin base material provided if necessary, and the near-infrared light shielding layer will be described.

[Optical function layer]
The optical functional layer according to the present invention includes a hydrophobic binder resin together with vanadium dioxide-containing fine particles having a number average particle diameter of at least 200 nm including all primary particles and secondary particles. And

[Vanadium dioxide-containing fine particles]
In the optical functional layer according to the present invention, vanadium dioxide-containing fine particles having a number average particle diameter of 200 nm or less of all particles including primary particles and secondary particles are dispersed and present in the hydrophobic binder resin. It is characterized by.

The crystal form of the vanadium dioxide-containing fine particles according to the present invention is not particularly limited, but from the viewpoint of efficiently expressing thermochromic properties (automatic light control), rutile vanadium dioxide-containing fine particles (VO ₂ -containing fine particles) are used. It is particularly preferable to use it.

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

  In the present invention, the number average particle size of all particles including primary particles and secondary particles of vanadium dioxide-containing fine particles in the optical functional layer is 200 nm or less.

  The number average particle size (nm) of all the particles including the primary particles and the secondary particles of the vanadium dioxide-containing fine particles in the optical functional layer can be determined according to the above-described method.

  The number average particle size of all particles including primary particles and secondary particles according to the present invention is 200 nm or less, preferably in the range of 1 to 180 nm, more preferably 5 to 5 nm. It is in the range of 100 nm, more preferably in the range of 10 to 80 nm.

  The primary particle diameter of the vanadium dioxide-containing fine particles is preferably in the range of 1 to 150 nm, more preferably in the range of 5 to 100 nm, and most preferably in the range of 10 to 50 nm. .

  In the optical film of the present invention, the primary particle number ratio of the vanadium dioxide-containing fine particles in the optical functional layer that can be determined by the above measurement method is 30% by number or more of the total number of primary particles and secondary particles. It is preferably 50% by number or more, particularly preferably 70% by number or more. The ideal upper limit is 100% by number, but the current maximum value is 95% by number or less.

  In addition, the aspect ratio of the vanadium dioxide-containing fine particles is preferably in the range of 1.0 to 3.0.

  The vanadium dioxide-containing 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 particle size in the single crystal state is sufficiently small, it is possible to exhibit better thermochromic properties as compared with conventional fine particles.

In the vanadium dioxide-containing fine particles according to the present invention, in addition to vanadium dioxide (VO ₂ ), for example, tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re) ), Iridium (Ir), osmium (Os), ruthenium (Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F) and phosphorus (P It may contain at least one element selected from the group consisting of By adding such an element, it becomes possible to control the phase transition characteristics (particularly the light control temperature) of the vanadium dioxide-containing fine particles. In addition, about 0.1-5.0 atomic% is sufficient for the total amount of such an additive (dopant) with respect to the vanadium dioxide containing fine particle finally obtained with respect to a vanadium (V) atom.

  Further, the concentration of the vanadium dioxide-containing 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, more preferably based on the total mass of the optical functional layer. 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-containing fine particles)
In general, a method for producing vanadium dioxide-containing fine particles includes a method of pulverizing a VO ₂ sintered body synthesized by a solid phase method, and a vanadium compound such as vanadium pentoxide (V ₂ O ₅ ) or ammonium vanadate as a raw material. And an aqueous synthesis method in which particles are grown while synthesizing VO ₂ in the liquid phase.

As a method for producing vanadium dioxide-containing fine particles according to the present invention, VO ₂ -containing fine particles are synthesized in a liquid phase using a vanadium compound as a raw material in that the average primary particle size is small and variation in particle size can be suppressed. However, an aqueous synthesis method in which particles are grown is preferable.

  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 (0015) of JP-A-2010-58984. Reference can be made to the production methods described in 0018).

Among the above aqueous synthesis methods, in the present invention, the hydrothermal synthesis method is applied, and the aqueous synthesis method is used to prepare an aqueous dispersion containing vanadium dioxide-containing fine particles, and the vanadium dioxide-containing fine particles in the aqueous dispersion are dried. Without preparing a solvent dispersion containing vanadium dioxide-containing fine particles by a solvent replacement step, and mixing with a hydrophobic binder resin solution in a dispersed state constituting primary particles in which the vanadium dioxide-containing fine particles are separated, A coating solution for forming an optical functional layer is prepared. The number average particle diameter of all the particles including the primary particles and the secondary particles of vanadium dioxide-containing fine particles is 200 nm or less by forming the optical functional layer using the coating liquid for forming the optical functional layer in this state. The optical functional layer according to the invention can be formed. Further, as a method for producing vanadium dioxide-containing fine particles, if necessary, fine particles such as fine TiO _{2 serving} as the core of particle growth are added as the core particles, and a vanadium dioxide phase is grown on the core particles to thereby produce a dioxide dioxide. Vanadium-containing fine particles can also be produced.

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

  Below, the manufacturing process of the vanadium dioxide containing fine particle by a typical hydrothermal synthesis method is shown.

(Process 1)
A raw material solution (A) is prepared by mixing the substance (I) containing vanadium (V), hydrazine (N ₂ H ₄ ) or a hydrate thereof (N ₂ H ₄ .nH ₂ O), and water. This raw material solution (A) is an aqueous solution in which the substance (I) containing vanadium (V) is dissolved in water, or a suspension state in which the substance (I) containing vanadium (V) is dispersed in water. It may be.

Examples of the substance (I) containing vanadium (V) include divanadium pentoxide (V ₂ O ₅ ), ammonium vanadate (NH ₄ VO ₃ ), vanadium trichloride (VOCl ₃ ), and 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) containing vanadium (V), and are easily dissolved in water. It has the property to do.

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

By adding these elements to the finally obtained vanadium dioxide (VO ₂ ) -containing single crystal fine particles, the thermochromic properties of the vanadium dioxide-containing fine particles, in particular, the transition temperature characteristics can be controlled.

Further, the raw material 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) which is the substance (I) can be uniformly dissolved.

(Process 2)
Next, a hydrothermal reaction treatment is performed using the prepared raw material 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 ) can be obtained by 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 appropriately set. The temperature of the hydrothermal reaction treatment is, for example, in the range of 250 to 350 ° C. Preferably, within the range of 250-300 ° C, more preferably within the range of 250-280 ° C. By reducing the temperature, the particle diameter of the obtained single crystal fine particles can be reduced, but if the particle diameter is excessively small, the crystallinity is lowered. 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 excessively long processing time results in a large energy consumption and a decrease in productivity.

(Process 3)
If necessary, the surface of the obtained vanadium dioxide-containing fine particles may be subjected to a coating treatment or a surface modification treatment with a resin. By these treatments, the surface of the vanadium dioxide-containing 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-containing 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 where the entire surface of the particle is completely covered with the resin with respect to the vanadium dioxide-containing 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 in vanadium dioxide-containing fine particle dispersion>
The dispersion of vanadium dioxide-containing fine particles prepared by the above aqueous synthesis method contains impurities such as residues generated in the synthesis process, and secondary aggregated particles are generated when the optical functional layer is formed. This may trigger a deterioration factor during 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-containing fine particle dispersion, a conventionally known method for separating foreign substances and impurities from the dispersion can be applied. For example, the vanadium dioxide-containing fine particle dispersion is centrifuged, the vanadium dioxide-containing fine particles are precipitated, the impurities in the supernatant are removed, the dispersion medium is added and dispersed again, or an exchange membrane such as an ultrafiltration membrane A method using an ultrafiltration membrane is most preferable from the viewpoint of preventing agglomeration of vanadium dioxide-containing fine particles.

  Examples of the constituent material of 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-containing fine particles: solvent substitution treatment)
In the present invention, after preparing an aqueous dispersion containing vanadium dioxide-containing fine particles by the above-mentioned aqueous synthesis method, the aqueous dispersion is used to convert the vanadium dioxide-containing fine particles by a solvent substitution step without passing through the drying process. It is preferred to prepare a solvent dispersion containing.

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

  The concentration means used in the concentration step of the specific dispersion containing vanadium dioxide-containing fine particles is preferably the same ultrafiltration method as described above.

  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. In the solvent replacement step, finally, water, which is a medium constituting the aqueous dispersion containing vanadium oxide-containing fine particles, is replaced with an organic solvent to prepare a solvent dispersion containing vanadium dioxide-containing fine particles. It is a process. 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 may be appropriately selected. Examples thereof include 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 has the ability to dissolve a 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. 4 is a schematic configuration diagram showing an example of a solvent replacement processing apparatus applicable to the present invention.

  A solvent replacement processing apparatus 10 shown in FIG. 4 includes a preparation tank 11 for storing a dispersion 12 containing vanadium dioxide-containing fine particles prepared by the method described above, and a solvent stock tank for storing a solvent 18 for dilution. 17. Ultrafiltration as a condensing means in the solvent supply line 19 for adding the solvent 18 to the adjustment kettle 11, the circulation line 13 for circulating the dispersion 12 in the preparation kettle 11 by the circulation pump 14, and the path of the circulation line 13. Part 15 is arranged.

Step (A):
The dispersion liquid 12 containing the vanadium dioxide-containing fine particles prepared by the method described above is stored in the preparation kettle 11, and the dispersion liquid 12 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, when the initial volume is 100% by volume, it is concentrated to 20% by volume. It is preferable to avoid excessive concentration beyond this because particle aggregation occurs with increase in particle density. In this concentration operation, it is important not to dry the dispersion.

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

Step (C):
Next, in the same manner as in the above step (A), while circulating with the circulation pump P, the medium (water + solvent) in the dispersion is discharged from the discharge port 16 outside the system by the ultrafiltration unit 15 and again. Concentrate 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 and mixed. A secondary solvent-substituted dispersion 12 is prepared.

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

  That is, in the solvent dispersion liquid containing vanadium dioxide-containing fine particles according to the present invention, water can be contained to some extent, and the standard is approximately 30% by mass or less, preferably 10% by mass or less, and particularly preferably. It is 5.0 mass% or less. Moreover, a minimum is 0.01 mass% or more, Preferably it is 0.05 mass% or more, Most preferably, it is 0.1 mass% or more. Therefore, 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-containing fine particles and the film forming property of the coexisting hydrophobic binder, and maintain the haze at a lower level. can do. Moreover, by setting it as 0.1 mass% or more, the change width of the infrared rays transmittance | permeability and infrared shielding factor at the time of a temperature change can further be expanded, and it is preferable conditions.

  Regarding the ultrafiltration method using an ultrafiltration membrane applicable in the solvent replacement treatment, for example, Research Disclosure No. 1 10208 (1972), no. 13122 (1975) and no. 16351 (1977) and the like can be referred to. The pressure difference and flow rate that are important as operating conditions can be set with reference to the characteristic curve described in Haruhiko Oya's “Membrane Utilization Technology Handbook”, Koshobo Publishing (1978), p275.

  As the ultrafiltration membrane applicable to the present invention, flat plate type, spiral type, cylindrical type, hollow fiber type, hollow fiber type and the like already incorporated as a module include Asahi Kasei Co., Ltd., 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.

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

[Hydrophobic binder resin]
The optical functional layer according to the present invention is characterized in that a hydrophobic binder resin is applied as a binder for holding vanadium dioxide-containing fine particles.

  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 applied to the present invention is preferably a resin polymerized in a curing process using a hydrophobic polymer or a monomer of a 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.

  Further, as another example of the hydrophobic binder resin applicable to the present invention, a resin that is polymerized in a curing process using a monomer of the hydrophobic binder resin can be exemplified.

  The typical hydrophobic binder resin material is a compound that is cured by irradiation with active energy rays such as ultraviolet rays and electron beams, specifically, a radical polymerizable compound that is cured by a polymerization reaction with radical active species, and a cation. Mention may be made of cationically polymerizable compounds which cure by a cationic polymerization reaction with active species.

  Examples of the radical polymerizable compound include a compound having an ethylenically unsaturated bond capable of radical polymerization, and examples of the compound having an ethylenically unsaturated bond capable of radical polymerization include, for example, acrylic acid, methacrylic acid, itaconic acid, Unsaturated carboxylic acids such as crotonic acid, isocrotonic acid, maleic acid and their salts, esters, urethanes, amides and anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, unsaturated Examples include radically polymerizable compounds such as urethane. 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, JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like exemplified in JP-A-2001-220526.

  It is preferable to contain a photopolymerization initiator together with the above compound. As 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, after applying a coating liquid for forming an optical functional layer containing each constituent material and a solvent dispersion containing vanadium dioxide-containing fine particles, for example, on a transparent substrate, thereafter, ultraviolet rays, electron beams, etc. Irradiate active energy rays. Thereby, the photocurable composition which comprises the formed optical function layer thin film hardens | cures rapidly.

  When irradiating ultraviolet rays as active energy rays, the light sources include, for example, ultraviolet LEDs, ultraviolet lasers, mercury arc lamps, xenon arc lamps, low pressure mercury lamps, fluorescent lamps, carbon arc lamps, tungsten-halogen copying lamps 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.

  On the other hand, as another method for forming the optical functional layer according to the present invention, as illustrated in FIG. 2, a solvent dispersion containing vanadium dioxide-containing fine particles in a hydrophobic resin that is a constituent material of a transparent substrate. And a solvent are added and dissolved to prepare a film-forming dope, and then a second embodiment that also serves as a resin base material by a solution fluent method that is used in film formation of a conventionally known film using the dope A method of forming a hybrid optical functional layer that can be also suitably used.

  Examples of the hydrophobic binder resin B2 that can be applied by the above-described method include resin materials that are conventionally used in the formation of optical films, such as polyethylene terephthalate (abbreviation: PET), polyethylene naphthalate (abbreviation: PEN). And the like, polyesters 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, and cellulose nitrate. Their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate (abbreviation: PC), norbornene resin, polyester Methylpentene, polyetherketone, polyimide, polyethersulfone (abbreviation: PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic and polyarylates, Examples thereof include cycloolefin (abbreviation: COP) resins such as Arton (trade name, manufactured by JSR) and Apel (trade name, manufactured by Mitsui Chemicals).

  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.

  A hybrid optical functional layer that also serves as a transparent substrate as illustrated in FIG. 2 is formed by a solution casting method using a dope prepared by mixing and preparing the above constituent materials.

[Other additives for optical functional layers]
In the optical functional layer according to the present invention, various additives can be added as long as the effects of the present invention are not impaired. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, JP-A-57- No. 878989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, JP-A-3-13376 and the like, an anion, Various surfactants of cation or nonion, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871, and JP-A-4-242 209266, etc., optical brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents Lubricants such as diethylene glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, viscosity reducing agents, lubricants, infrared absorbers And various known additives such as dyes and pigments.

[Method for forming optical functional layer]
Although there is no restriction | limiting in particular as a formation method of the optical function layer which concerns on this invention, As a formation method of the optical function layer 3 which is 1st embodiment, vanadium dioxide containing microparticles | fine-particles are prepared from an aqueous synthesis method, and it is made to dry. After preparing the solvent dispersion containing vanadium dioxide-containing fine particles by the solvent replacement process without passing through the process, mix and dissolve with hydrophobic binder resin, etc. to prepare the non-aqueous optical functional layer forming coating liquid One of the preferable forming methods is a method of forming the optical functional layer 3 according to the first embodiment by applying the non-aqueous coating solution for forming the optical functional layer on a transparent substrate by a wet coating method and drying it. Is.

  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.

  In addition, as a method for forming the hybrid optical functional layer that also serves as the resin substrate according to the second embodiment, a solution fluent method that is generally known as a film forming method can be applied. As a film forming method, for example, JP2013-067074, JP2013-123868, JP2013-202979, JP2014-066958, JP2014-095729, JP It can be formed according to the solution casting film forming method described in Japanese Patent Application Laid-Open No. 2014-159082.

<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, flexibility and production suitability (manufacturing process suitability, roll From the viewpoint of suitability for two rolls, etc., a transparent resin film is preferable. “Transparent” in the present invention means that the average light transmittance in the visible light region is 20% or more, preferably 30% or more, more preferably 50% or more, and particularly preferably 70% 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 suppression of thermal expansion. 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%.

  As the transparent substrate applicable to the optical film of the present invention, 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 film and the like can be used, and cycloolefin film, polyester film, and triacetyl cellulose film 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 formation process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating.

<< Near-infrared shielding layer >>
In the optical film of the present invention, in addition to the optical functional layer, a near-infrared light shielding layer having a function of shielding at least part of the light wavelength range of 700 to 1000 nm may be provided.

  For details of the near infrared light shielding layer applicable to the present invention, for example, JP 2012-131130 A, JP 2012-139948 A, JP 2012-185342 A, JP 2013-080178 A. The constituent elements and forming methods described in JP-A-2014-089347 and the like can be referred to.

<< 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.

<< Production of optical film >>
[Production of Optical Film 101]
(Preparation of vanadium dioxide-containing fine particle dispersion 1: no particle drying step)
0.433 g of ammonium vanadate (NH ₄ VO ₃ , manufactured by Wako Pure Chemical Industries, special grade) was 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. For 8 hours, followed by hydrothermal reaction at 270 ° C. for 24 hours to prepare an aqueous vanadium dioxide-containing fine particle dispersion 1 in which vanadium dioxide-containing fine particles are dispersed at a concentration of 3.0% by mass.

(Preparation of solvent-based vanadium dioxide-containing fine particle dispersion 2 by ultrafiltration treatment of vanadium dioxide-containing fine particle dispersion 1)
An ultrafiltration apparatus having a filtration membrane made of polyethersulfone and having a molecular weight cut off of 300,000 (Nippon Millipore). The vanadium dioxide-containing fine particle dispersion 1 prepared above is kept at 20 ° C. and is circulated in the system. Concentration operation was performed using the solvent displacement treatment apparatus shown in FIG. 4 equipped with Pelicon 2 cassette (manufactured by Co., Ltd.). When the initial volume of the vanadium dioxide-containing fine particle dispersion 1 was 100%, the concentration was reduced to 20% by volume. Then, ethyl alcohol was added to make 100% by volume. Next, this dispersion was concentrated again to 20% by volume, then methyl ethyl ketone was added as a solvent to make 100% by volume, and the solvent was subjected to two solvent substitution treatments. The solvent concentration of the vanadium dioxide-containing fine particles was 3% by mass. Dispersion 2 was prepared.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 2 was measured by the Karl Fischer method and found to be 4.05% by mass.

(Preparation of coating solution 1 for forming an optical functional layer)
The following constituent materials were sequentially added, mixed and dissolved to prepare a solvent-based coating solution 1 for forming an optical functional layer.

3% by mass of vanadium dioxide-containing fine particle dispersion 2 (solvent: methyl ethyl ketone) 28 parts by mass 5% by mass of hydrophobic binder resin (solvent: methyl ethyl kenton, solute: Byron 200 (amorphous polyester resin, manufactured by Toyobo Co., Ltd.)) 60 parts by mass (formation of optical functional layer)
On the 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 above-prepared coating solution 1 for forming an optical functional layer has a layer thickness after drying. Wet application was carried out under the condition of 1.5 μm, and then hot air of 110 ° C. was blown for 2 minutes to dry to form an optical functional layer, thereby producing an optical film 101 having the configuration shown in FIG.

[Production of Optical Film 102]
(Preparation of vanadium dioxide-containing fine particle dispersion 3)
In the preparation of the vanadium dioxide-containing fine particle dispersion 2, the dispersion 2 was further concentrated to 20% by volume using the same solvent substitution apparatus, and then methyl ethyl ketone was added to make 100% by volume. Was performed three times to prepare a solvent-based vanadium dioxide-containing fine particle dispersion 3 having a particle concentration of 3% by mass.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 3 was measured by the Karl Fischer method and found to be 0.84% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, instead of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 3 was used to prepare an optical functional layer-forming coating solution and form an optical functional layer. An optical film 102 was produced in the same manner except that.

[Preparation of optical film 103]
(Preparation of vanadium dioxide-containing fine particle dispersion 4)
In the preparation of the vanadium dioxide-containing fine particle dispersion 3, the dispersion 3 was further concentrated to 20% by volume using the same solvent substitution apparatus, and then methyl ethyl ketone was added to make 100% by volume. Was performed four times to prepare a solvent-based vanadium dioxide-containing fine particle dispersion 4 having a particle concentration of 3% by mass.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 4 was measured by the Karl Fischer method and found to be 0.03% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, in place of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 4 is used to prepare a coating liquid for forming an optical functional layer and to form an optical functional layer. An optical film 103 was produced in the same manner except that.

[Preparation of optical film 104]
(Preparation of vanadium dioxide-containing fine particle dispersion 5)
In the preparation of the vanadium dioxide-containing fine particle dispersion 4, the dispersion 4 was further concentrated to 20% by volume using the same solvent substitution apparatus, and then methyl ethyl ketone was added to make 100% by volume. The solvent-based vanadium dioxide-containing fine particle dispersion 5 having a particle concentration of 3% by mass was prepared.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 5 was measured by the Karl Fischer method and found to be 0.008% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, in place of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 5 is used to prepare a coating liquid for forming an optical functional layer and to form an optical functional layer. An optical film 104 was produced in the same manner except that.

[Preparation of optical film 105]
(Preparation of vanadium dioxide-containing fine particle dispersion 6)
In the state where the prepared vanadium dioxide-containing fine particle dispersion 1 was kept at 20 ° C., concentration operation was performed using the same solvent displacement treatment apparatus shown in FIG. 4 as described above, and the initial vanadium dioxide-containing fine particle dispersion 1 When the volume was 100%, after concentrating to 30% by volume, ethyl alcohol was added to make 100% by volume. Next, this dispersion was concentrated again to 30% by volume, then methyl ethyl ketone was added as a solvent to make 100% by volume, and the solvent substitution treatment was performed twice, and the solvent-based vanadium dioxide-containing fine particles having a particle concentration of 3% by mass. Dispersion 6 was prepared.

  As a result of measuring the water content in the prepared vanadium oxide-containing fine particle dispersion 6 by the Karl Fischer method, it was 9.10% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, in place of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 6 is used to prepare a coating liquid for forming an optical functional layer and to form an optical functional layer. An optical film 105 was produced in the same manner except that.

[Preparation of optical film 106]
(Preparation of vanadium dioxide-containing fine particle dispersion 7)
In the state where the prepared vanadium dioxide-containing fine particle dispersion 1 was kept at 20 ° C., concentration operation was performed using the same solvent displacement treatment apparatus shown in FIG. 4 as described above, and the initial vanadium dioxide-containing fine particle dispersion 1 When the volume is 100%, after concentrating to 28% by volume, ethyl alcohol is added to make 100% by volume, and a solvent replacement treatment is performed once to contain vanadium dioxide in a solvent system with a particle concentration of 3% by mass. A fine particle dispersion 7 was prepared.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 7 was measured by the Karl Fischer method and found to be 28.10% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, instead of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 7 was used to prepare an optical functional layer-forming coating solution and to form an optical functional layer. An optical film 106 was produced in the same manner except that.

[Preparation of optical film 107]
(Preparation of vanadium dioxide-containing fine particle dispersion 8)
In the state where the prepared vanadium dioxide-containing fine particle dispersion 1 was kept at 20 ° C., concentration operation was performed using the same solvent displacement treatment apparatus shown in FIG. 4 as described above, and the initial vanadium dioxide-containing fine particle dispersion 1 When the volume is 100%, after concentrating to 50% by volume, ethyl alcohol is added to make 100% by volume, and the solvent substitution treatment is performed once to contain vanadium dioxide in a solvent system with a particle concentration of 3% by mass. A fine particle dispersion 8 was prepared.

  The water content in the prepared vanadium oxide-containing fine particle dispersion 8 was measured by the Karl Fischer method and found to be 50.10% by mass.

(Preparation of coating solution for forming optical functional layer and formation of optical functional layer)
In the production of the optical film 101, in place of the vanadium dioxide-containing fine particle dispersion 2, the above-prepared vanadium dioxide-containing fine particle dispersion 8 is used to prepare a coating liquid for forming an optical functional layer and to form an optical functional layer. An optical film 107 was produced in the same manner except that.

[Preparation of optical film 108]
In the production of the optical film 102, the same amount of polyvinyl butyral resin (abbreviation: PVB) was used instead of the amorphous polyester resin (Byron 200), which is the hydrophobic binder resin used in the preparation of the coating solution 2 for forming the optical functional layer. The optical film 108 was produced in the same manner except that the optical functional layer was formed using the coating solution 9 for forming an optical functional layer prepared using the above.

(Preparation of optical functional layer forming coating solution 8)
The following constituent materials were sequentially added, mixed and dissolved to prepare a solvent-based coating solution 8 for forming an optical functional layer.

3% by mass of vanadium dioxide-containing fine particle dispersion 3 (solvent: methyl ethyl ketone) 28 parts by mass 5% by mass of hydrophobic binder resin (solvent: methyl ethyl kenton / toluene = 1/1, solute: polyvinyl butyral resin (ESREC BX-1) Manufactured by Sekisui Chemical Co., Ltd.)) 60 parts by mass [Preparation of optical film 109]
In the production of the optical film 102, the same amount of diacetyl cellulose (abbreviation: DAC) is used instead of the amorphous polyester resin (Byron 200) which is a hydrophobic binder resin used in the preparation of the coating liquid 2 for forming the optical functional layer. An optical film 109 was produced in the same manner except that the optical functional layer was formed with the coating solution 9 for forming an optical functional layer prepared using the above.

(Preparation of coating solution 9 for forming an optical functional layer)
The following constituent materials were sequentially added, mixed and dissolved to prepare a solvent-based coating solution 9 for forming an optical functional layer.

3% by mass of vanadium dioxide-containing fine particle dispersion 3 (solvent: methyl ethyl ketone) 28 parts by mass 5% by mass of hydrophobic binder resin (solvent: methyl ethyl keton, solute: diacetyl cellulose, degree of acetylation = 55%, weight average molecular weight = 180,000)
60 parts by mass [Production of optical film 110]
In the preparation of the vanadium dioxide-containing fine particle dispersion 3 used for the production of the optical film 102, the solvent replacement treatment was performed by a vacuum distillation method using an evaporator instead of the method using the ultrafiltration device described in FIG. In the same manner, a vanadium dioxide-containing fine particle dispersion 9 was prepared, and an optical film 110 was produced in the same manner except that this was used.

[Preparation of optical film 111]
In the production of the optical film 102, an optical film 111 was produced in the same manner except that the optical functional layer was formed by using the following optical functional layer forming coating liquid 11 instead of the optical functional layer forming coating liquid 2. did.

(Preparation of coating solution 11 for forming an optical functional layer)
The following constituent materials were sequentially added, mixed and dissolved to prepare a solvent-based coating solution 11 for forming an optical functional layer.

3% by mass of vanadium dioxide-containing fine particle dispersion 3 (solvent: methyl ethyl ketone) 28 parts by mass 5% by mass of UV curable hydrophobic binder resin (solvent: MEK, trade name V-7600B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., polyfunctional) Urethane acrylate, abbreviation: UA) 60 parts by mass Photopolymerization initiator: Irgacure 184 (manufactured by BASF Japan)
0.15 parts by mass (formation of optical functional layer)
Conditions for the layer thickness after drying of the coating liquid 11 for forming an optical functional layer prepared above on a transparent substrate of a polyethylene terephthalate film (A4300 manufactured by Toyobo Co., Ltd., double-sided adhesive layer) having a thickness of 50 μm After applying using a wire bar in an air atmosphere, curing is performed under a condition of 400 mJ / cm ² as illuminance using a UV curing device (using a high pressure mercury lamp) manufactured by Eye Graphics Co., Ltd. Then, drying for 3 minutes was performed at 80 degreeC, and the optical film 111 was produced.

[Preparation of optical film 112]
An optical film 112 was produced in the same manner except that the vanadium dioxide-containing fine particle dispersion 3 prepared by the following method was used in place of the vanadium dioxide-containing fine particle dispersion 3 used for producing the optical film 102.

(Preparation of vanadium dioxide-containing fine particle dispersion 10)
Instead of ammonium vanadate (NH ₄ VO ₃ , Wako Pure Chemical Industries, special grade), which is the supply source of vanadium atoms used for the preparation of the vanadium dioxide-containing fine particle dispersion ₃ , divanadium pentoxide (V ₂ O ₅ ) A vanadium dioxide-containing fine particle dispersion 10 containing vanadium dioxide-containing fine particles was prepared in the same manner except that was used according to a known synthesis method.

[Preparation of optical film 113]
(Preparation of vanadium dioxide-containing fine particle dispersion 11)
In the state where the prepared aqueous vanadium dioxide-containing fine particle dispersion 1 was kept at 20 ° C., concentration operation was performed using a solvent substitution apparatus having the same configuration as described in FIG. When the volume of the fine particle dispersion 1 was 100%, after concentrating to 20% by volume, ethyl alcohol was added to make 100% by volume. Next, the dispersion was concentrated again to 20% by volume, methylene chloride (abbreviation: MC) was added as a solvent to 100% by volume, and the dispersion was further concentrated to 20% by volume. A solvent-based vanadium dioxide-containing fine particle dispersion 11 having a particle concentration of 3% by mass is prepared by adding chloride to 100% by volume to prepare a solvent-based vanadium dioxide-containing fine particle dispersion 11, Finemet manufactured by Nippon Seisen Co., Ltd. Filtered with NF.

  The water content in the prepared vanadium dioxide-containing fine particle dispersion 11 was measured by the Karl Fischer method and found to be 0.84% by mass.

(Preparation of dope)
First, methylene chloride and ethanol shown below were added to the pressure dissolution tank. Triacetyl cellulose (abbreviation: TAC) and the prepared vanadium dioxide-containing fine particle dispersion 11 were charged into a pressure dissolution tank containing an organic solvent while stirring. While this was heated and stirred, triacetylcellulose 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>
Methylene chloride 487 parts by weight Ethanol 45 parts by weight Hydrophobic polymer resin: Triacetyl cellulose (triacetyl cellulose synthesized from linter cotton, acetyl group substitution degree = 2.88, Mn = 150,000, Mw = 300,000) 100 parts by weight 3 Mass part vanadium dioxide-containing fine particle dispersion 11 33 parts by mass (film formation)
Using the prepared dope, an optical film 113 as a hybrid optical functional layer was produced according to the solution casting film forming method described in JP2014-095729A and JP2014-159082A.

[Preparation of optical film 114]
(Preparation of dope)
The following methylene chloride was added to the pressure dissolution tank. The cycloolefin polymer (abbreviation: COP) and the prepared vanadium dioxide-containing fine particle dispersion 11 were charged into a pressure 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>
Methylene chloride 192 parts by weight Hydrophobic polymer resin: cycloolefin polymer (trade name: Arton, manufactured by JSR Corporation) 76.9 parts by weight 3% by weight of vanadium dioxide-containing fine particle dispersion 11 12.0 parts by weight (film formation)
Using the prepared dope, an optical film 114 as a hybrid optical functional layer was produced according to the solution casting film forming method described in JP2014-095729A and JP2014-159082.

[Preparation of optical film 115]
(Preparation of dope)
The following methylene chloride was added to the pressure dissolution tank. Polymethylmethacrylate (abbreviation: PMMA) as an acrylic resin and the above prepared vanadium dioxide-containing fine particle dispersion 11 were added to a pressure dissolution tank containing an organic solvent while stirring. While this was heated and stirred, polymethyl methacrylate was dissolved, and this was dissolved in Azumi filter paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. The dope was prepared by filtration using 244.

<Dope composition>
Methylene chloride 192 parts by weight Hydrophobic polymer resin: acrylic resin (polymethyl methacrylate, trade name: VB-7103, manufactured by Mitsubishi Rayon Co., Ltd.) 76.9 parts by weight 3% by weight of vanadium dioxide-containing fine particle dispersion 11 25. 6 parts by mass (film formation)
Using the prepared dope, an optical film 115 as a hybrid optical functional layer was produced in accordance with the solution casting film forming method described in JP 2014-095729 A and JP 2014-159082 A.

[Preparation of optical film 116]
In the production of the optical film 101, an optical film 116 was produced in the same manner except that the following vanadium dioxide-containing fine particle dispersion 12 was used instead of the vanadium dioxide-containing fine particle dispersion 2.

(Preparation of vanadium dioxide-containing fine particle dispersion 12: particle drying step)
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.). A 5% by mass aqueous solution of (special grade) was slowly added dropwise to prepare Solution 1 having a pH value of 9.2 at 23 ° C. and 55% RH. 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. For 8 hours, followed by hydrothermal reaction at 270 ° C. for 24 hours.

  Next, the obtained reaction product was filtered, and the filtration residue was filtered and washed with water and ethanol. Furthermore, this reaction product was dried at 60 ° C. for 10 hours using a constant temperature dryer to obtain vanadium dioxide-containing fine particles.

  Subsequently, the obtained vanadium dioxide-containing fine particle powder was added to methyl ethyl ketone so as to have a concentration of 3.0% by mass to prepare a mixed solution, which was then mixed with an ultrasonic disperser (SMH, UH-300). Ultrasonic dispersion treatment for a minute was performed and redispersed to prepare a vanadium dioxide-containing fine particle dispersion 12.

[Preparation of optical film 117]
In the production of the optical film 101, an optical film 117 was produced in the same manner except that the following vanadium dioxide-containing fine particle dispersion 13 was used instead of the vanadium dioxide-containing fine particle dispersion 2.

(Preparation of vanadium dioxide-containing fine particle dispersion 13: particle drying step)
13.7 g of vanadyl triisopropoxide was dissolved in 500 mL of isopropanol. After adding 15 mL of ion exchange water to this solution and stirring at room temperature for 72 hours, the solvent (isopropanol) was removed. The residue was crushed, calcined at 400 ° C. for 2 hours, and subsequently calcined in a hydrogen stream at 450 ° C. for 2 hours to obtain vanadium dioxide-containing fine particles by a calcining method.

  Subsequently, the obtained vanadium dioxide-containing fine particle powder was added to methyl ethyl ketone so as to have a concentration of 3.0% by mass to prepare a mixed solution, which was then mixed with an ultrasonic disperser (SMH, UH-300). The mixture was redispersed by performing an ultrasonic dispersion treatment for a minute to prepare a vanadium dioxide-containing fine particle dispersion 13.

[Preparation of optical film 118]
(Preparation of vanadium dioxide-containing fine particle dispersion 14: particle drying step)
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.). A 5% by mass aqueous solution of (special grade) was slowly added dropwise to prepare Solution 1 having a pH value of 9.2 at 23 ° C. and 55% RH. 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. For 8 hours, followed by hydrothermal reaction at 270 ° C. for 24 hours.

  Next, the obtained reaction product was filtered, and the filtration residue was filtered and washed with water and ethanol. Furthermore, this reaction product was dried at 60 ° C. for 10 hours using a constant temperature dryer to obtain vanadium dioxide-containing fine particles.

  Subsequently, the obtained powder of vanadium dioxide-containing fine particles was added to pure water so as to have a concentration of 3.0% by mass to prepare a mixed solution, and an ultrasonic disperser (UH-300 manufactured by SMT) was used. An ultrasonic dispersion treatment was performed for 5 minutes to redisperse, and a vanadium dioxide-containing fine particle dispersion 14 was prepared.

(Preparation of coating solution 17 for forming an optical functional layer)
The following constituent materials were sequentially added, mixed and dissolved to prepare an aqueous optical functional layer forming coating solution 17.

3% by weight aqueous vanadium dioxide-containing fine particle dispersion 14 28 parts by weight 3% by weight boric acid aqueous solution 10 parts by weight 5% by weight polyvinyl alcohol (5% by weight aqueous solution, PVA-124; degree of polymerization: 2400, degree of saponification : 98-99 mol%; manufactured by Kuraray Co., Ltd.)
60 parts by weight 5% by weight surfactant aqueous solution (Softazoline LSB-R, manufactured by Kawaken Fine Chemical Co., Ltd.) 2 parts by weight PVA-124, which is polyvinyl alcohol, has a hydroxy group-containing repeating unit ratio of 50 mol%. These are the above hydrophilic polymers.

(Formation of optical functional layer)
On the transparent base material of a polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, the coating liquid 17 for optical function layer formation prepared above is dried using an extrusion coater. Wet application was performed under the condition of 1.5 μm, and then hot air at 110 ° C. was blown for 2 minutes to dry to form an optical functional layer, whereby an optical film 118 was produced.

<< Measurement of optical film characteristic values >>
About each produced said optical film, the number average particle diameter and primary particle ratio of the vanadium dioxide containing microparticles | fine-particles in an optical function layer were measured in accordance with the following method.

  The side surface of the optical functional layer constituting each optical film was trimmed with a microtome to expose a cross section as shown in FIG. 1 or FIG. Next, the exposed cross section was photographed at a magnification of 10,000 using a transmission electron microscope (TEM). The particle size of all the vanadium dioxide-containing fine particles present in a certain region of the photographed cross section was measured.

At this time, 300 vanadium dioxide-containing fine particles were measured. The shot particles, the primary particles are single particles, as shown in FIG. 1 or FIG. 2, 2 are included and particles or the secondary particles are aggregates of vanadium dioxide primary particles VO _S The particle size measures the diameter of each independent particle. In addition, for vanadium dioxide in which two or more particles are aggregated, the projected area of the entire aggregate was obtained, and then the projected area was converted into a circle, and the diameter was taken as the particle size.

  The number average diameter (nm) was determined for each diameter of the primary particles and secondary particles determined as described above. Next, for each particle measured above, the ratio of primary particles to the total number of particles (particle number%) was determined.

  Table 1 shows the configuration of the optical films 101 to 118 produced as described above and the characteristic values of the particles.

  The details of each component described in the abbreviation in Table 1 are as follows.

(Resin base material)
PET: Polyethylene terephthalate (solvent type)
MEK: Methyl ethyl ketone MC: Methylene chloride (hydrophobic binder resin)
PVB: Polyvinyl butyral DAC: Diacetyl cellulose UA: UV curable hydrophobic binder resin (polyfunctional urethane acrylate)
TAC: triacetyl cellulose COP: cycloolefin polymer PMMA: acrylic resin (polymethyl methacrylate)
(Hydrophilic resin)
PVA: Polyvinyl alcohol << Evaluation of optical film >>
Next, the following evaluations were performed on each of the produced optical films.

(Evaluation of haze)
About each produced said optical film, haze (%) was measured using the haze meter (Nippon Denshoku Industries make, NDH2000) at room temperature (25 degreeC), and the haze was evaluated according to the following reference | standard.

A: Haze is less than 2.0% B: Haze is 2.0% or more and less than 3.0% B: Haze is 3.0% or more and less than 5.0% B : 5.0% or more and less than 8.0% ×: 8.0% or more (Measurement of visible light transmittance)
As a result of measuring the visible light transmittance simultaneously with the haze measurement, both the present invention and the comparative example had a visible light transmittance of 50% or more. The rate of change described later tends to be greatly estimated when the transmittance is low, but this influence is small in both the present invention and the comparative sample.

(Evaluation of temperature dependence of spectral transmittance)
About each produced optical film, the spectral transmittance meter V-570 by JASCO Corporation was used for each spectral transmittance in the environment of 25 degreeC * 55% RH, and the environment of 80 degreeC * 50% RH. Each transmittance at 1500 nm in the infrared region was measured, the change rate of the spectral transmittance was measured according to the following formula, and the temperature dependence of the spectral transmittance was evaluated according to the following criteria. It was determined that the larger the change rate, the better the heat shielding effect in summer and the light transmission in winter, and the higher temperature dependence.

Rate of change of the spectral transmittance (%) = [(25 spectral transmittance _Ramuda1500 in the spectral transmittance _λ1500 -80 ℃ · 55% RH at ° C. · 55% RH) / 25 spectral transmittance at ℃ · 55% RH _λ1500] × 100
A: Change rate of spectral transmittance is 50% or more ○: Change rate of spectral transmittance is 45% or more and less than 50% ○ Δ: Change rate of spectral transmittance is 40% or more, 45 Δ: Spectral transmittance change rate is 30% or more and less than 40% Δ ×: Spectral transmittance change rate is 20% or more and less than 30% ×: Spectral transmittance 20 % (Evaluation of temperature dependence after forced deterioration treatment)
Each optical film produced above was subjected to a forced deterioration treatment for 3 days in a high-temperature and high-humidity environment of 55 ° C. and 80% RH, and then, similarly to the evaluation of the temperature dependence of the spectral transmittance, 25 ° C./55 Each spectral transmittance under the environment of% RH and under the environment of 80 ° C. and 50% RH is measured by using a spectral transmittance meter V-570 manufactured by JASCO Corporation, and each transmittance at 1500 nm which is an infrared region. Measurements were made to determine the rate of change, and the temperature dependence after forced degradation treatment was evaluated according to the same evaluation criteria as described above.

  Even after storage in a high-temperature and high-humidity environment of 55 ° C. and 80% RH, it was determined that the durability was excellent if the change width was maintained.

  The results obtained as described above are shown in Table 2.

  As is clear from the results shown in Table 2, the optical film having the optical functional layer having the configuration defined in the present invention has a low haze, a large temperature dependence of spectral transmittance, and a high temperature compared to the comparative example. It can be seen that excellent temperature dependence of the spectral transmittance is maintained even after storage in a high humidity environment.

  The optical film of the present invention has a thermochromic property capable of adjusting the near-infrared shielding rate according to the temperature environment, has low haze, excellent storage stability in a high humidity environment, and transmits infrared rays when the temperature changes. It is an optical film that has a large rate of change between the effect and the infrared shielding effect, and can be sandwiched between a pair of glass components to form a laminated glass. This laminated glass can be used in automobiles, railway vehicles, aircraft, ships, and architecture. It can utilize suitably as a window glass member for objects.

DESCRIPTION OF SYMBOLS 1 Optical film 2 Transparent base material 3 Optical functional layer 2 + 3 Hybrid optical functional layer 4 Near-infrared light shielding layer 10 Solvent substitution processing apparatus 11 Preparation kettle 12 Dispersion liquid containing vanadium dioxide containing fine particles 13 Circulation line 14 Circulation pump 15 Ultrafiltration part 16 outlet 17 solvent stock holder 18 solvent 19 solvent supply line B1, B2 hydrophobic binder resin L the light incident side VO _S primary particles VO _M vanadium dioxide containing fine secondary particles of the vanadium dioxide-containing microparticles

Claims (8)

A method for producing an optical film comprising a step of forming an optical functional layer containing at least vanadium dioxide-containing fine particles and a hydrophobic binder resin,
The number average particle size of all particles including the primary particles and secondary particles of the vanadium dioxide-containing fine particles is adjusted to be 200 nm or less,
The vanadium dioxide-containing fine particles, was prepared as an aqueous dispersion containing a vanadium dioxide-containing microparticles prepared by the water-based synthesis, the aqueous dispersion, the vanadium dioxide-containing particulates without going through the dry state, the solvent replacement step the method of manufacturing an optical optical film you comprises preparing a solvent dispersion containing vanadium dioxide-containing fine particles by. The method for producing an optical film according to claim 1, wherein the hydrophobic binder resin is a resin polymerized in a curing process using a hydrophobic polymer or a monomer of a hydrophobic binder resin . The solvent replacement step is composed of a concentration step of a dispersion containing vanadium dioxide-containing fine particles and a solvent dilution step of adding a solvent to the concentrate obtained in the concentration step, and a processing operation in the concentration step and the solvent dilution step. The method for producing an optical film according to claim 1 , wherein the process is repeated twice or more to prepare a solvent dispersion containing vanadium dioxide-containing fine particles. The method for producing an optical film according to claim 3 , wherein the concentration means used in the step of concentrating the dispersion containing the vanadium dioxide-containing fine particles is an ultrafiltration method. The solvent dispersion liquid containing vanadium dioxide-containing fine particles prepared by the solvent substitution step contains water in the range of 0.01 to 30% by mass, any one of claims 1 to 4 The method for producing an optical film according to claim 1. An optical functional layer forming coating solution containing a solvent dispersion containing vanadium dioxide-containing fine particles prepared by the solvent substitution step and a hydrophobic binder is prepared, and the optical functional layer forming coating solution is applied onto a transparent substrate. the method for producing an optical film according to any one of claims 1 to 5, characterized in that dried to form an optical function layer. An optical functional layer-forming dope comprising a solvent dispersion containing vanadium dioxide-containing fine particles prepared by the solvent substitution step and a hydrophobic binder is prepared, and the optical functional layer-forming dope is optically layered by a solution casting method. the method for producing an optical film according to any one of claims 1 to 6, characterized in that to form the. In addition to the optical functional layer, claim 1, characterized in that to form a near-infrared light-shielding layer having a function to shield at least a portion of the light wavelength range of 700~1000nm to claim 7 The manufacturing method of the optical film of one term.

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