JP2018087094A - Production method of vanadium dioxide-containing particle, vanadium dioxide-containing particle, fluid dispersion and optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of vanadium dioxide-containing particles having high purity, and excellent in thermochromic property.SOLUTION: In a production method of vanadium dioxide-containing particles, which is a production method of vanadium dioxide-containing particles containing vanadium dioxide having thermochromic property, reaction liquid containing a raw material containing a vanadium compound, a reducer and water, in which a value of an equivalence ratio of the reducer to the vanadium compound is in the range of 1.00-1.40 is subjected to a hydrothermal reaction, to thereby form vanadium dioxide-containing particles.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing vanadium dioxide-containing particles, vanadium dioxide-containing particles, a dispersion, and an optical film. More specifically, the present invention relates to a method for producing vanadium dioxide-containing particles having high purity and excellent thermochromic properties, vanadium dioxide-containing particles, a dispersion, and an optical film.

  For example, in a building such as a house or a building and a moving body such as a vehicle, energy is saved in a place where a large heat exchange occurs between the inside (for example, indoors, inside the vehicle) and the external environment (for example, window glass). In order to achieve both compatibility and comfort, application of a material having thermochromic properties (hereinafter also referred to as a thermochromic material) capable of controlling the blocking or transmission of heat is expected.

  The thermochromic material is a material whose optical properties such as a transparent state / reflective state change with temperature, for example. Specifically, the material is in a reflective state when the temperature is high, and in a transparent state when the temperature is low. When such a thermochromic material is applied to, for example, a window glass of a building, it can block heat by reflecting sunlight in the summer, and can transmit heat by transmitting sunlight in the winter. And comfort.

At present, one of the thermochromic materials that has received most attention is vanadium dioxide-containing particles containing vanadium dioxide (VO ₂ ) (hereinafter also simply referred to as “VO ₂ -containing particles”). Vanadium dioxide is known to exhibit thermochromic properties (property of reversibly changing optical properties depending on temperature) during phase transition near room temperature. By utilizing this property, a thermochromic material depending on the environmental temperature can be obtained.

In the crystal structure of VO ₂ , there are several crystal phase polymorphs such as A phase, B phase, C phase and R phase (so-called “rutile-type crystal phase”). Among these, the crystal structure exhibiting thermochromic properties as described above is limited to the R phase. Since this R phase has a monoclinic structure below the transition temperature, it is also called an M phase. In such a VO ₂ -containing particle, in order to exhibit substantially excellent thermochromic properties, there is no presence of a metal that does not exhibit thermochromic properties or a crystal phase other than the M phase of vanadium dioxide in the particles. desirable.

As a method for forming a thermochromic member (such as a film), VO ₂ -containing particles or a dispersion thereof is prepared, and this is bonded to a member that is desired to exhibit thermochromic properties via an adhesive or the like. It has been studied to manufacture a member having thermochromic properties (see, for example, Patent Documents 1 and 2).

However, since the VO ₂ -containing particles obtained by hydrothermal reaction shown in Patent Document 1 are obtained by epitaxially growing vanadium dioxide on titanium dioxide (TiO ₂ ) particles, they contain titanium dioxide as an impurity. There is a problem that the purity of vanadium is lowered and the thermochromic property is lowered.

On the other hand, for VO ₂ -containing particles obtained by hydrothermal reaction shown in Patent Document 2, vanadium pentoxide (V ₂ O ₅ ) and hydrazine hydrate (N ₂ H ₄ .H ₂ O) In the ratio described in Example 2, the amount of hydrazine, which is a reducing agent, is large and contains a large amount of vanadium oxide that does not exhibit thermochromic properties, so that the thermochromic properties are sufficiently expressed. There is a problem that it is not.

JP 2010-031235 A JP2011-178825A

  The present invention has been made in view of the above-described problems and circumstances, and its solution is a method for producing vanadium dioxide-containing particles having high purity and excellent thermochromic properties, vanadium dioxide-containing particles, dispersion, and optical Is to provide a film.

  In order to solve the above problems, the present inventor, in the process of examining the cause of the above problems, by hydrothermally reacting a reaction solution in which the value of the equivalent ratio of the reducing agent to the vanadium compound is within a specific range. The inventors have found that a method for producing vanadium dioxide-containing particles having high purity and excellent thermochromic properties, vanadium dioxide-containing particles, a dispersion, and an optical film can be provided, and the present invention has been achieved.

  That is, the said subject which concerns on this invention is solved by the following means.

1. A method for producing vanadium dioxide-containing particles containing vanadium dioxide having thermochromic properties,
By hydrothermally reacting a reaction solution containing a raw material containing a vanadium compound, a reducing agent, and water, and having an equivalent ratio of the reducing agent to the vanadium compound within a range of 1.00 to 1.40. The method for producing vanadium dioxide-containing particles, wherein the vanadium dioxide-containing particles are formed.

  2. The method for producing vanadium dioxide-containing particles according to item 1, wherein the pH of the reaction solution after hydrothermal reaction (in terms of 25 ° C) is in the range of 4.0 to 7.0.

  3. 3. The method for producing vanadium dioxide-containing particles according to item 1 or 2, wherein the stirring time after addition of the reducing agent is 1 to 200 minutes.

  4). The method for producing vanadium dioxide-containing particles according to any one of claims 1 to 3, wherein a liquid temperature during hydrothermal reaction of the reaction liquid is in a range of 250 to 350 ° C. .

  5. The method for producing vanadium dioxide-containing particles according to any one of items 1 to 4, wherein the hydrothermal reaction time is 12 to 72 hours.

  6). The reaction solution is a compound containing at least one atom selected from the group consisting of tungsten, molybdenum, niobium, tantalum, tin, rhenium, iridium, osmium, ruthenium, germanium, chromium, iron, gallium, aluminum, fluorine and phosphorus. The manufacturing method of the vanadium dioxide containing particle | grains as described in any one of 1st term | claim to 5th term | claim characterized by the above-mentioned.

7). The vanadium dioxide-containing particles produced by the method for producing vanadium dioxide-containing particles according to any one of items 1 to 6,
Vanadium dioxide-containing particles characterized by containing at least vanadium dioxide and having thermochromic properties.

  8). A dispersion liquid comprising the vanadium dioxide-containing particles according to item 7.

9. An optical film having an optical functional layer containing at least a resin on a transparent substrate,
The optical functional layer contains the vanadium dioxide-containing particles described in item 7 above.

  By the above means of the present invention, it is possible to provide a method for producing vanadium dioxide-containing particles having high purity and excellent thermochromic properties, vanadium dioxide-containing particles, a dispersion, and an optical film.

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

In the hydrothermal reaction, when the value of the equivalent ratio of the reducing agent to the vanadium compound is less than 1.00, only the particle surface is reduced, the reduction does not proceed to the inside, and the value of the equivalent ratio is greater than 1.40. Although the reduction proceeds to the inside of the particle, the particle surface is excessively reduced.
Therefore, in the method for producing VO ₂ -containing particles of the present invention, a high purity is obtained by hydrothermally reacting a reaction solution in which the value of the equivalent ratio of the reducing agent to the vanadium compound is in the range of 1.00 to 1.40. In addition, it is presumed that VO ₂ -containing particles having excellent thermochromic properties can be provided.

Moreover, VO ₂ contains VO ₂ containing particles obtained by the production method of the particles of the present invention, since high purity (less impurities), high crystallinity M phase of VO ₂ containing particles (hereinafter, simply _VO 2 (M )) And the stability (heat resistance, oxidation resistance, etc.) of the particles is improved. In addition, since VO ₂ (M) having a sharp endothermic peak can be obtained, thermochromic properties sensitive to temperature changes can be obtained. Furthermore, VO ₂ (M) that is not affected by absorption derived from another metal can be obtained.

Schematic sectional view showing an example of the configuration of the optical film of the present invention Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near infrared light shielding layer on both surfaces of a transparent substrate Schematic sectional view showing an example of the configuration of the optical film of the present invention having a near-infrared light shielding layer formed of a polymer layer laminate

Method for producing a VO ₂ containing particles of the present invention comprises a process for the preparation of VO ₂ containing particles containing vanadium dioxide having thermochromic properties, feedstock containing vanadium compound, the reducing agent and water, and vanadium A VO ₂ -containing particle is formed by hydrothermal reaction of a reaction solution having an equivalent ratio of a reducing agent to a compound in a range of 1.00 to 1.40. This feature is a technical feature common to the inventions according to claims 1 to 9.

As an embodiment of the present invention, from the viewpoint of improving the stability of VO ₂ -containing particles, the pH of the reaction solution after hydrothermal reaction (in terms of 25 ° C.) is in the range of 4.0 to 7.0. Is preferred.

  Moreover, it is preferable that the stirring time after addition of a reducing agent is 1 to 200 minutes. If the stirring time after addition of the reducing agent is 1 minute or more, the reduction reaction is stable, and if it is 200 minutes or less, volatilization / decomposition of the reducing agent can be suppressed.

  In addition, from the viewpoint of improving the crystallinity and thermochromic properties of vanadium dioxide, it is preferable to set the liquid temperature during the hydrothermal reaction of the reaction liquid within a range of 250 to 350 ° C, and further, the time of the hydrothermal reaction is increased. It is preferably 12 to 72 hours.

The reaction solution contains at least one atom selected from the group consisting of tungsten, molybdenum, niobium, tantalum, tin, rhenium, iridium, osmium, ruthenium, germanium, chromium, iron, gallium, aluminum, fluorine, and phosphorus. It is preferable to contain a compound. Thus, the phase transition (thermochromic) temperature of the VO ₂ -containing particles can be changed.

The method for producing VO ₂ -containing particles of the present invention can provide VO ₂ -containing particles containing at least vanadium dioxide and having thermochromic properties.

Further, it is possible to provide a dispersion containing VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention.

Further, it is possible to provide an optical film VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention is added to the optical functional layer.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" showing a numerical range is used by the meaning containing the numerical value described before and behind that as a lower limit and an upper limit.

<< Method for Producing Vanadium Dioxide-Containing Particles (VO ₂ -Containing Particles) >>
Method for producing a VO ₂ containing particles of the present invention comprises a process for the preparation of VO ₂ containing particles containing vanadium dioxide having thermochromic properties, feedstock containing vanadium compound, the reducing agent and water, and vanadium A VO ₂ -containing particle is formed by hydrothermal reaction of a reaction solution having an equivalent ratio of a reducing agent to a compound in a range of 1.00 to 1.40.

The following describes in detail a method for manufacturing the VO ₂ containing particles of the present invention.

(1) Preparation of reaction solution First, a reaction solution is prepared by mixing at least a raw material containing a vanadium compound, a reducing agent, and water. This reaction solution may be an aqueous solution in which the vanadium compound is dissolved in water, or may be a suspension in which the vanadium compound is dispersed in water.

(Equivalent ratio value)
The reaction solution according to the present invention is characterized in that the value of the equivalent ratio of the reducing agent to the vanadium compound is in the range of 1.00 to 1.40.
Hereinafter, the case where divanadium pentoxide (V ₂ O ₅ ) is used as the vanadium compound and hydrazine (N ₂ H ₄ ) or oxalic acid (H ₂ C ₂ O ₄ ) is used as the reducing agent will be described.

Reactions of divanadium pentoxide (V ₂ O ₅ ) with hydrazine (N ₂ H ₄ ) or oxalic acid (H ₂ C ₂ O ₄ ) are represented by the following reaction formulas (1) and (2), respectively. .

Reaction formula (1)
2V ₂ O ₅ + N ₂ H ₄ → 4VO ₂ + N ₂ + 2H ₂ O

Reaction formula (2)
V ₂ O ₅ + H ₂ C ₂ O ₄ → 2VO ₂ + 2CO ₂ + H ₂ O

As shown in the reaction formula (1), the reduction reaction of divanadium pentoxide and hydrazine proceeds at a molar ratio of 2: 1. That is, in the reduction reaction, the value of the equivalent ratio of the reducing agent to the vanadium compound is in the range of 1.00 to 1.40 means that the molar ratio of hydrazine (reducing agent) to divanadium pentoxide (vanadium compound). Is within the range of 0.50 to 0.70.
On the other hand, as shown in the reaction formula (2), the reduction reaction of divanadium pentoxide and oxalic acid proceeds at a molar ratio of 1: 1. That is, in the reduction reaction, that the value of the equivalent ratio of the reducing agent to the vanadium compound is within the range of 1.00 to 1.40 means that the molar amount of oxalic acid (reducing agent) relative to divanadium pentoxide (vanadium compound). It means that the ratio is in the range of 1.00 to 1.40.

  In the present invention, the value of the equivalent ratio of the reducing agent to the vanadium compound is particularly preferably 1.20. If the value of the equivalent ratio is 1.20, the reducing agent reacts with a solvent, not a vanadium compound, and a part of the reducing agent decomposes or volatilizes, so that the amount of reducing agent approaches the reaction equivalent, and purity. Can be increased.

(Vanadium compounds)
The vanadium compound according to the present invention is not particularly limited as long as it is a pentavalent vanadium (V) compound. For example, divanadium pentoxide (V ₂ O ₅ ), ammonium vanadate (NH ₄ VO ₃ ), three Examples thereof include vanadium chloride (VOCl ₃ ) and sodium metavanadate (NaVO ₃ ).

(Reducing agent)
The reducing agent according to the present invention has a property of easily dissolving in water, and at least functions as a reducing agent for vanadium compounds. For example, hydrazine (N ₂ H ₄ ) and hydrates thereof (N ₂ H ₄ · nH ₂ O), oxalic acid (H ₂ C ₂ O ₄ ), and the like.

(water)
Although the water which concerns on this invention is not specifically limited, The highly purified thing with few impurities is preferable, Specifically, purified water, such as ion-exchange water and distilled water, can be used.

(Other compounds that the reaction solution may contain)
Examples of the reaction solution according to the present invention include tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir), osmium (Os), At least one atom selected from the group consisting of ruthenium (Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F) and phosphorus (P) A compound containing may be contained.

By adding a compound containing these atoms to the VO ₂ -containing particles finally obtained as an additive, the thermochromic properties (particularly the transition temperature) of the VO ₂ -containing particles can be controlled.

Further, an oxidizing or reducing substance may be added to the reaction solution according to the present invention. An example of such a substance is hydrogen peroxide (H ₂ O ₂ ). By adding an oxidizing or reducing substance, the pH of the reaction solution can be adjusted, or the vanadium compound can be uniformly dissolved.

(2) Hydrothermal reaction Next, a hydrothermal reaction treatment is performed using the prepared solution. Here, the 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). A hydrothermal reaction process is implemented in an autoclave apparatus, for example. By the hydrothermal reaction treatment, VO ₂ -containing particles containing vanadium dioxide are obtained.

The conditions of the hydrothermal reaction treatment (amount of reactants, treatment temperature, treatment pressure, treatment time) are appropriately set. For example, the liquid temperature during the hydrothermal reaction of the reaction solution is within the range of 250 to 350 ° C. Is preferred.
The hydrothermal reaction treatment time is preferably 12 to 72 hours.
The hydrothermal reaction is preferably carried out with stirring, whereby the particle size of the VO ₂ -containing particles can be made more uniform. The stirring time is preferably 1 to 200 minutes.

  In addition, the hydrothermal reaction process may be implemented by a batch type and may be implemented by a continuous type.

Through the above steps, a suspension containing VO ₂ -containing particles containing vanadium dioxide having thermochromic properties is obtained. Thereafter, the VO ₂ -containing particles of the present invention are obtained from the suspension by filtration, washing, drying and the like.

In the method of manufacturing the VO ₂ containing particles of the present invention, pH of the reaction solution after the hydrothermal reaction (25 ° C. equivalent), preferably in the range of 4.0 to 7.0.

(Vanadium dioxide containing particles (VO ₂ containing particles))
VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention contains at least vanadium dioxide, and has a thermochromic.

The average particle diameter of the VO ₂ -containing particles is preferably in the range of 5 to 50 nm.
The CV value of the particle size distribution of the VO ₂ -containing particles is preferably 40% or less.
When such VO ₂ -containing particles are applied to an optical film or the like, generation of haze can be suppressed and visible light transmittance can be improved.

In the present invention, the average particle size of the VO ₂ -containing particles is obtained by photographing the particles with a scanning electron microscope, defining the diameter of a circle having an area equal to the projected area of the particles as the particle size, and about 100 VO ₂ particles. Measurement is performed to obtain an arithmetic average value of these values, which is defined as an average particle size.
Further, the CV value of the particle size distribution of the VO ₂ -containing particles is obtained by multiplying the value obtained by dividing the standard deviation of the individual particle sizes obtained by the measurement of the average particle size by the average particle size by 100. The CV value of the particle size distribution is used. That is, the CV value of the particle size distribution of the VO ₂ -containing particles is a value calculated by the following formula.

  CV value of particle size distribution = standard deviation of particle size / average particle size × 100 (%)

(Thermochromic properties)
The VO ₂ -containing particles of the present invention have optical transparency (referring to optical transparency in the visible light region of a film containing VO ₂ -containing particles) and thermochromic properties.
The higher the light transmittance in the visible light region of the film containing the VO ₂ -containing particles of the present invention, the better, and it is preferably 70% or more.
Further, the thermochromic property of the VO ₂ -containing particles is not particularly limited as long as optical characteristics such as light transmittance and light reflectance change reversibly due to temperature change. For example, the difference in light transmittance at 20 ° C. and 80 ° C. is preferably 30% or more.
Thermochromic film containing VO ₂ containing particles, for example, using a spectrophotometer V-670 (JASCO Corp.), can be measured as a difference in light transmittance at a wavelength of 2000 nm.

In addition to vanadium dioxide, the VO ₂ -containing particles of the present invention include tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), and 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 kind of atom. By containing such atoms, it becomes possible to control the phase transition characteristics (particularly the dimming temperature) of the VO ₂ -containing particles. In addition, the total content of the atoms that may be contained in the finally obtained VO ₂ -containing particles is about 0.1 to 5.0 at% with respect to the vanadium (V) atom (100 at%). . If it is in this range, there is no possibility that the thermochromic property (for example, the difference in transmittance before and after light control) of the VO ₂ -containing particles is deteriorated.

<Dispersion>
If the VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention are dispersed in an organic solvent or inorganic solvent such as water, such as alcohols, containing at least vanadium dioxide, and A dispersion containing VO ₂ -containing particles having thermochromic properties can be provided.
The solvent for dispersing is not particularly limited, and a known solvent can be used.

The thermochromic property of the dispersion containing VO ₂ -containing particles is, for example, 20 ° C. at a wavelength of 1300 nm that is not affected by the absorption peak of water using a spectrophotometer V-670 (manufactured by JASCO Corporation) and It can be measured as a difference in light transmittance at 80 ° C.

<< Optical film (1) >>
The optical film of the present invention, on a transparent substrate has an optical functional layer containing at least a resin, on the optical functional layer, VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention It is contained.

As shown in FIG. 1, the optical film 1 of the present invention is configured by laminating an optical functional layer 3 on a transparent substrate 2. This optical functional layer 3 is in a state in which the VO ₂ -containing particles 3b are dispersed in the resin 3a.

The optical film of the present invention preferably further has a near infrared light shielding layer having a function of shielding at least part of the wavelength range of 700 to 1000 nm.
Further, the near-infrared light shielding layer includes a high refractive index reflective layer containing the first water-soluble binder resin and the first metal oxide particles, the second water-soluble binder resin, and the second metal oxide. It is preferable that the reflective layer laminate be configured by alternately laminating low refractive index reflective layers containing physical particles and selectively reflecting light of a specific wavelength.

  For example, the optical film 1 shown in FIG. 2 has a configuration in which a near-infrared light shielding layer is sandwiched between the transparent substrate 2 and the optical functional layer 3, and the optical film 1 shown in FIG. The optical functional layer 3 and the near-infrared light shielding layer 4 are laminated on the material 2 in this order, and the optical film 1 shown in FIG. The near-infrared light shielding layer 4 is disposed on the opposite side to the opposite side.

  Hereinafter, the configuration of the near infrared light shielding layer 4 will be described in detail with reference to FIGS.

FIG. 5 is a cross-sectional view showing in detail the configuration of the near-infrared light shielding layer 4 in the optical film 1 shown in FIG.
As shown in FIG. 5, the optical film 1 of the present invention includes a first water-soluble binder resin and a first metal oxide as a near infrared light shielding layer between the transparent substrate 2 and the optical functional layer 3. High refractive index infrared reflective layer (high refractive index reflective layer) containing particles, and low refractive index infrared reflective layer (low refractive index) containing a second water-soluble binder resin and second metal oxide particles The reflection layer laminate ML1 in which the rate reflection layers are alternately laminated is sandwiched.
The configuration of the reflective layer laminate ML1 is composed of n layers from the transparent substrate 2 side to the infrared reflective layers T _{1 to} T _n , for example, T ₁ , T ₃ , T ₅ ,. A high refractive index reflective layer comprising a low refractive index reflective layer in the range of 10 to 1.60, and T ₂ , T ₄ , T ₆ ,... Having a refractive index in the range of 1.80 to 2.50 The configuration can be given as an example.
Here, the refractive index in the present invention is a value measured in an environment of 25 ° C.

Similarly, FIG. 6 is a cross-sectional view showing in detail the configuration of the near-infrared light shielding layer 4 in the layer arrangement of the optical film 1 shown in FIG. 3, and FIG. 7 is the optical film shown in FIG. 1 is a cross-sectional view showing in detail the configuration of a near-infrared light shielding layer 4 in the layer arrangement 1.
Further, as shown in FIG. 8, the optical film 1, a reflective layer laminate ML1a on both surfaces of the transparent substrate 2 (the infrared reflective layer _Ta 1 to Ta _n) and the reflecting layer stack ML1b (infrared reflective layer _Tb 1 _{~Tb n} ), And the optical functional layers 3A and 3B may be disposed on the respective reflective layer laminates ML1a and ML1b.

On the other hand, as shown in FIG. 9, in the optical film 1 of the present invention, a near-infrared light shielding layer constituted by the polymer layer laminate ML <b> 2 is sandwiched between the transparent substrate 2 and the optical functional layer 3. Yes.
The polymer layer laminate ML2 is configured by laminating two types of polymer films having different materials. As an example of the configuration, from the transparent substrate 2 side, PEN ₁ formed of a polyethylene naphthalate (PEN) film, PMMA ₁ , PEN ₂ , and PMMA ₂ formed of a polymethyl methacrylate (PMMA) film. , PEN ₃ , PMMA ₃ ,..., PMMA _m−1 , PEN _m , PMMA _m , PEN _{m + 1} are sequentially laminated to form a polymer layer laminate ML2. The optical functional layer 3 is disposed on the polymer layer laminate ML2.

The optical film of the present invention may be provided with various functional layers as necessary in addition to the above-described constituent layers.
The layer thickness of the optical film of the present invention is not particularly limited, but is in the range of 250 to 1500 μm, preferably in the range of 400 to 1200 μm, more preferably in the range of 600 to 1000 μm, particularly Preferably it exists in the range of 750-900 micrometers.
As an optical characteristic of the optical film of the present invention, the visible light transmittance measured by JIS R 3106 (1998) is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more. It is.
Moreover, it is preferable to have the area | region (peak) exceeding light reflectivity 50% in the area | region of wavelength 900-1400nm.

<Each film material>
The optical film of the present invention has an optical functional layer containing at least VO ₂ -containing particles and a resin on a transparent substrate. Furthermore, it is a preferable aspect to have a near-infrared light shielding layer having a function of shielding at least part of the wavelength range of 700 to 1000 nm.
Hereinafter, the components of the optical film of the present invention will be described in detail.

<< Transparent substrate (2) >>
The transparent substrate applicable to the optical film of the present invention is not particularly limited as long as it is transparent, and examples thereof include glass, quartz, and a transparent resin film. From the viewpoint of suitability, it is preferably a transparent resin film.
The term “transparent” as used in the present invention means that the average light transmittance in the visible light region is 50% or more, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

The thickness of the transparent substrate according to the present invention is preferably in the range of 30 to 200 μm, more preferably in the range of 30 to 100 μm, and still more preferably in the range of 35 to 70 μm.
If the thickness of the transparent substrate is 30 μm or more, when a transparent resin film is used as the transparent substrate, wrinkles and the like are less likely to occur during handling, and if the thickness is 200 μm or less, laminated glass At the time of production, followability to a curved surface at the time of bonding to a glass substrate is improved.

  The transparent substrate according to the present invention is preferably a biaxially oriented polyester film, but an unstretched or at least one stretched polyester film can also be used. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression. In particular, when the laminated glass provided with the optical film of the present invention is used as a windshield of an automobile, 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 wrinkles of the optical film and cracking of the near infrared light shielding layer. It is preferable that it is in the range of 1.5 to 3.0%, more preferably in the range of 1.9 to 2.7%.

  As described above, the transparent substrate applicable to the optical film of the present invention is not particularly limited as long as it is transparent, but various resin films are preferably used. For example, a polyolefin film (for example, polyethylene , Polypropylene, etc.), polyester films (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, triacetyl cellulose films, etc. can be used, and polyester films and triacetyl cellulose films are preferred.

Although it does not specifically limit as a polyester film (henceforth only polyester), It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components.
The main constituent dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid.
Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like.
Among the polyesters having these as main components, from the viewpoints of transparency, mechanical strength, dimensional stability, etc., as dicarboxylic acid components, terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

When a transparent resin film is used as the transparent substrate according to the present invention, particles may be contained within a range that does not impair transparency in order to facilitate handling. Examples of particles that can be used for the transparent resin film include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, Examples thereof include organic particles such as crosslinked polymer particles and calcium oxalate. Examples of the method of adding particles include a method of adding particles in the raw polyester, a method of adding directly to an extruder, etc., and adopting one of these methods. The two methods may be used in combination.
In the present invention, an additive may be added in addition to the particles as necessary. Examples of such additives include stabilizers, lubricants, crosslinking agents, anti-blocking agents, antioxidants, dyes, pigments, ultraviolet absorbers, and the like.

  The transparent substrate according to the present invention can be produced by a conventionally known general method. For example, in the case of a transparent resin film, an unstretched transparent resin film that is substantially amorphous and not oriented is obtained by melting a resin as a material with an extruder, extruding it with an annular die or a T die, and rapidly cooling it. Can be manufactured. The unstretched transparent resin film is uniaxially stretched, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular simultaneous biaxial stretching, and other known methods such as transparent resin film flow (vertical axis) direction. Alternatively, a stretched transparent resin film can be produced by stretching in the direction perpendicular to the flow direction of the transparent resin film (horizontal axis). Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of the transparent resin film, it is preferably 2 to 10 times in the vertical axis direction and the horizontal axis direction.

In addition, the transparent resin film may be subjected to relaxation treatment or off-line heat treatment in terms of dimensional stability. The relaxation treatment is preferably carried out in the process from the heat setting during the stretch film formation process of the polyester film to the winding after the tenter is taken out from the transverse stretcher. The relaxation treatment is preferably performed at a treatment temperature in the range of 80 to 200 ° C, and more preferably at a treatment temperature in the range of 100 to 180 ° C.
Moreover, it is preferable that the relaxation rate is 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is 2 to 6%. The relaxed substrate is subjected to off-line heat treatment to improve heat resistance and further improve dimensional stability.

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. Examples of resins used in the undercoat layer coating solution useful in the present invention include polyester resins, acrylic-modified polyester resins, polyurethane resins, acrylic resins, vinyl resins, vinylidene chloride resins, polyethyleneimine vinylidene resins, polyethyleneimine resins, and polyvinyl alcohol resins. , Modified polyvinyl alcohol resin, gelatin and the like, and any of them can be preferably used. A conventionally well-known additive can also be added to these undercoat layers. The undercoat layer can be coated by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating. The coating amount of the undercoat layer is preferably about 0.01 to ² g / m ² (dry state).

<< Optical function layer (3) >>
Optical functional layer according to the present invention, VO ₂ containing particles produced by the production method of the VO ₂ containing particles of the present invention is characterized in that it is contained is distributed.
The crystal form of the VO ₂ -containing particles is not particularly limited, but it is particularly preferable to use particles containing rutile vanadium dioxide from the viewpoint of efficiently expressing thermochromic properties (automatic light control). Further, the optical functional layer according to the present invention may contain VO ₂ -containing particles of other crystal types such as A-type or B-type within a range not impairing the purpose.

(resin)
The resin applicable to the optical functional layer according to the present invention is not particularly limited, but for example, a water-soluble polymer can be suitably used.

The water-soluble polymer is the temperature at which the water-soluble polymer is most dissolved, and is filtered through a G2 glass filter (maximum pores 40 to 50 μm) when dissolved in water so that the concentration is 0.5% by mass. In this case, the mass of the insoluble matter separated by filtration is within 50% by mass of the added water-soluble polymer.
Among such water-soluble polymers, the aforementioned gelatin, cellulose, thickening polysaccharide, or polymer having a reactive functional group can be preferably used. These water-soluble polymers may be used alone or in combination of two or more.

  Moreover, in this invention, the water-soluble polymer which comprises an optical function layer, and the 1st water-soluble binder resin or 2nd water-soluble binder resin which comprise the reflecting layer laminated body mentioned later are the same kind. Is a preferred embodiment.

(Other additives for optical functional layers)
The optical functional layer according to the present invention may contain an additive as long as the effects of the present invention are not impaired.
Examples of the additives include ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, JP-A-62-261476, JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, JP-A-3-13376, etc., Various anionic, cationic or nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871, JP-A-4 -219266, etc., pH brighteners such as sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide and potassium carbonate, antifoaming agents, and polyethylene Lubricants such as glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, lubricants, infrared absorbers And various known additives such as dyes and pigments.

(Method for forming optical functional layer)
As a method of forming an optical functional layer according to the present invention is not particularly limited, in the present invention, in the manufacturing method of the VO ₂ containing particles of the present invention, a reaction liquid obtained by hydrothermal reaction, for optical functional layer formed A preferable forming method is a method in which the optical functional layer is formed by applying and drying the optical functional layer forming coating liquid on a transparent substrate by a wet coating method.

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

<< Near-infrared light shielding layer (4) >>
The optical film of the present invention may have a near-infrared light shielding layer, and a typical configuration thereof is a reflection in which an infrared reflection layer containing a water-soluble binder resin and metal oxide particles is laminated in multiple layers. Examples thereof include a layer laminate ML1 (see FIGS. 5 to 8) or a polymer layer laminate ML2 (see FIG. 9). In particular, an infrared reflective layer having a different refractive index containing a water-soluble binder resin and metal oxide particles is used. It is preferable that the reflective layer laminate is a multilayer laminate.

<Reflective layer laminate>
The reflective layer laminate only needs to have at least one infrared reflective layer, but from the viewpoint of exhibiting an excellent heat insulating effect against solar radiation and electromagnetic wave permeability, the refractive index as exemplified in FIGS. It is a particularly preferred embodiment that the laminated body is a multilayer body in which different infrared reflective layers are laminated.
As described above, the reflective layer laminate includes a high refractive index infrared reflective layer (high refractive index layer) containing at least a first water-soluble binder resin and first metal oxide particles, and at least a second water-soluble layer. It has the structure which laminated | stacked alternately the low-refractive-index infrared reflection layer (low-refractive-index layer) containing a conductive binder resin and a 2nd metal oxide particle.

  In the optical film of the present invention, the resin constituting the optical functional layer and the first water-soluble binder resin or the second water-soluble binder resin constituting the reflective layer laminate may be the same kind of binder resin. Furthermore, it is more preferable that it is polyvinyl alcohol.

In the reflective layer laminate, the layer thickness per layer of the high refractive index layer is preferably in the range of 20 to 800 nm, and more preferably in the range of 50 to 350 nm.
Further, the layer thickness per layer of the low refractive index layer is preferably in the range of 20 to 800 nm, and more preferably in the range of 50 to 350 nm.

  Here, when measuring the layer thickness of each layer, the high refractive index layer and the low refractive index layer may have a clear interface therebetween, or the interface is gradually changing. May be. In the case where the interface is gradually changed, Δn = maximum refractive index−minimum refractive index in the region where the respective layers are mixed and the refractive index continuously changes. A point having a refractive index represented by (rate + Δn / 2) is regarded as a layer interface.

  The metal oxide concentration profile of the reflective layer laminate formed by alternately laminating the high refractive index layer and the low refractive index layer is etched from the surface to the depth direction using a sputtering method, and XPS (X− This can be confirmed by measuring the atomic composition ratio by sputtering at a rate of 0.5 nm / min with the outermost surface of 0 nm using a (ray photoelectron spectroscopy) surface analyzer. Moreover, it is also possible to obtain | require by cut | disconnecting a reflecting layer laminated body and measuring an atomic composition ratio with a XPS surface analyzer for a cut surface. In the mixed region, when the metal oxide concentration changes discontinuously, the boundary can be confirmed by a tomographic photograph taken with a transmission electron microscope (TEM).

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

  From the viewpoint of productivity, the reflective layer laminate preferably has a total number of high refractive index layers and low refractive index layers in the range of 6 to 100 layers, more preferably in the range of 8 to 40 layers. Yes, more preferably in the range of 9-30 layers.

  The reflective layer stack is preferably designed so that the refractive index difference between the high refractive index layer and the low refractive index layer is large, so that the infrared reflectance can be increased with a small number of layers. In the present invention, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is preferably 0.10 or more, more preferably 0.30 or more, still more preferably 0.35 or more, and particularly preferably. Is 0.40 or more. However, regarding the uppermost layer and the lowermost layer, a configuration outside the above preferred range may be used.

  Further, the reflectance in the specific wavelength region is determined by the difference in refractive index between two adjacent layers and the number of stacked layers, and the same reflectance can be obtained with a smaller number of layers as the difference in refractive index increases. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain a near-infrared reflectance of 90% or more, if the difference in refractive index is less than 0.1, it is necessary to laminate 200 layers or more, which not only decreases productivity but also scattering at the interface of the layers. Becomes larger, the transparency is lowered, and it becomes very difficult to manufacture without failure. From the viewpoint of improving the reflectance and reducing the number of layers, there is no upper limit to the difference in refractive index, but the limit is substantially about 1.40.

  In the reflective layer laminate, a layer configuration in which the layer adjacent to the transparent resin film is a low refractive index layer is preferable from the viewpoint of adhesion to the transparent resin film.

  Moreover, it is preferable that the 1st and 2nd water-soluble binder resin contained in a high refractive index layer or a low refractive index layer is polyvinyl alcohol. Moreover, it is preferable that the saponification degree of the polyvinyl alcohol contained in the high refractive index layer and the saponification degree of the polyvinyl alcohol contained in the low refractive index layer are different. Furthermore, the first metal oxide particles contained in the high refractive index layer are preferably titanium oxide particles, and more preferably titanium oxide particles surface-treated with a silicon-containing hydrated oxide. .

<High refractive index layer>
The high refractive index layer contains at least the first water-soluble binder resin and the first metal oxide particles, and may contain a curing agent, other resins, a surfactant, various additives, and the like as necessary. .
The refractive index of the high refractive index layer is preferably in the range of 1.80 to 2.50, more preferably in the range of 1.90 to 2.20.

(First water-soluble binder resin)
The first water-soluble binder resin is the temperature at which the water-soluble binder resin is most dissolved, and when dissolved in water so that the concentration is 0.5% by mass, the G2 glass filter (maximum pores 40-50 μm) The mass of the insoluble matter that is separated by filtration when filtered through is within 50% by mass of the added water-soluble binder resin.

The weight average molecular weight of the first water-soluble binder resin according to the present invention is preferably in the range of 1000 to 200000, and more preferably in the range of 3000 to 40000.
The weight average molecular weight referred to in the present invention can be measured by a known method, for example, static light scattering, gel permeation chromatography (GPC), time-of-flight mass spectrometry (TOF-MASS), or the like. In the present invention, the measurement is performed by gel permeation chromatography which is a generally known method.

  The content of the first water-soluble binder resin in the high refractive index layer is preferably in the range of 5 to 50% by mass with respect to 100% by mass of the solid content of the high refractive index layer, and is 10 to 40% by mass. It is more preferable to be within the range.

The first water-soluble binder resin applied to the high refractive index layer is not particularly limited, but a hydrophilic polymer can be suitably used. For example, gelatin (for example, gelatin described in JP-A-2006-343391) can be used. Representative hydrophilic polymers), starch, guar gum, alginate, methyl cellulose, ethyl cellulose, hydroxyalkyl cellulose, carboxyalkyl cellulose, polyacrylamide, polyethyleneimine, polyethylene glycol, polyalkylene oxide, polyvinyl pyrrolidone (PVP), polyvinyl methyl ether , Carboxyvinyl polymer, polyacrylic acid, sodium polyacrylate, naphthalenesulfonic acid condensate, proteins such as albumin and casein, sodium alginate, dextrin, dextran, dex It can be given a run like sugar derivatives such as sulfate.
Among them, gelatin having a high affinity with VO ₂ -containing particles, and further a polymer containing 50 mol% or more of repeating unit components having a hydroxy group, which has a high effect of preventing particle aggregation even during drying of film formation. , Celluloses, polyvinyl alcohols, polyvinyl pyrrolidones, acrylic resins having a hydroxy group, and the like, and polyvinyl alcohols and celluloses can be preferably used.
Moreover, it is preferable that water-soluble binder resin applied to the low refractive index layer mentioned later is also polyvinyl alcohol.

  The high refractive index layer and the low refractive index layer preferably contain two or more types of polyvinyl alcohol having different saponification degrees. Here, in order to distinguish, polyvinyl alcohol as a water-soluble binder resin used in the high refractive index layer is polyvinyl alcohol (A), and polyvinyl alcohol as a water-soluble binder resin used in the low refractive index layer is polyvinyl alcohol (B). And In addition, when each refractive index layer contains a plurality of polyvinyl alcohols having different saponification degrees and polymerization degrees, the polyvinyl alcohol having the highest content in each refractive index layer is changed to polyvinyl alcohol (A ) And polyvinyl alcohol (B) in the low refractive index layer.

  The “degree of saponification” as used herein refers to the ratio of hydroxy groups to the total number of acetyloxy groups (derived from the starting vinyl acetate) and hydroxy groups in polyvinyl alcohol.

In addition, when referring to “polyvinyl alcohol having the highest content in the refractive index layer” herein, the degree of polymerization is calculated assuming that the polyvinyl alcohol having a saponification degree difference of 3 mol% or less is the same polyvinyl alcohol. . However, a low polymerization degree polyvinyl alcohol having a polymerization degree of 1000 or less is a different polyvinyl alcohol even if the difference in the saponification degree is within 3 mol%.
Specifically, when polyvinyl alcohol having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% is contained in the same layer by 10 mass%, 40 mass%, and 50 mass%, respectively. These three polyvinyl alcohols are the same polyvinyl alcohol, and these three mixtures are polyvinyl alcohol (A) or (B).
In addition, the above-mentioned “polyvinyl alcohol having a saponification degree difference of 3 mol% or less” suffices to be within 3 mol% when attention is paid to any polyvinyl alcohol. For example, 90 mol%, 91 mol%, 92 mol%, 94 mol % Of polyvinyl alcohol, when paying attention to 91 mol% of polyvinyl alcohol, the difference in saponification degree of any polyvinyl alcohol is within 3 mol%, so that the same polyvinyl alcohol is obtained.

  When polyvinyl alcohol having a saponification degree different by 3 mol% or more is contained in the same layer, it is regarded as a mixture of different polyvinyl alcohols, and the polymerization degree and the saponification degree are calculated for each. For example, PVA203: 5% by mass, PVA117: 25% by mass, PVA217: 10% by mass, PVA220: 10% by mass, PVA224: 10% by mass, PVA235: 20% by mass, PVA245: 20% by mass, most contained A large amount of PVA (polyvinyl alcohol) is a mixture of PVA 217 to 245 (the difference in the degree of saponification of PVA 217 to 245 is within 3 mol%, and thus is the same polyvinyl alcohol), and this mixture is polyvinyl alcohol (A) or (B). Thus, in a mixture of PVA 217 to 245 (polyvinyl alcohol (A) or (B)), the degree of polymerization is about 3200 (= (1700 × 0.1 + 2000 × 0.1 + 2400 × 0.1 + 3500 × 0.2 + 4500 × 0.00). 2) /0.7), and the degree of saponification is 88 mol%.

  The difference in the absolute value of the degree of saponification between the polyvinyl alcohol (A) and the polyvinyl alcohol (B) is preferably 3 mol% or more, and more preferably 5 mol% or more. If it is such a range, since the interlayer mixing state of a high refractive index layer and a low refractive index layer will become a preferable level, it is preferable. Moreover, although the difference of the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is so preferable that it is separated, it is 20 mol% or less from the viewpoint of the solubility to water of polyvinyl alcohol. It is preferable.

  Moreover, it is preferable that the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is 75 mol% or more from a soluble viewpoint to water. Furthermore, between the polyvinyl alcohol (A) and the polyvinyl alcohol (B), one of them has a saponification degree of 90 mol% or more and the other is 90 mol% or less. It is preferable to bring the state to a desirable level. It is more preferable that one of the polyvinyl alcohol (A) and the polyvinyl alcohol (B) has a saponification degree of 95 mol% or more and the other is 90 mol% or less. In addition, although the upper limit of the saponification degree of polyvinyl alcohol is not specifically limited, Usually, it is less than 100 mol% and is about 99.9 mol% or less.

In addition, the polymerization degree of two kinds of polyvinyl alcohols having different saponification degrees is preferably 1000 or more, particularly preferably those having a polymerization degree in the range of 1500 to 5000, and in the range of 2000 to 5000. Those are more preferably used. This is because when the polymerization degree of polyvinyl alcohol is 1000 or more, the coating film does not crack, and when it is 5000 or less, the coating solution is stabilized. In the present invention, “the coating solution is stable” means that the coating solution is stable over time.
Furthermore, it is preferable that the polymerization degree of at least one of polyvinyl alcohol (A) and polyvinyl alcohol (B) is in the range of 2000 to 5000. Since the reflectance of a wavelength improves, it is preferable.
It is preferable that the polymerization degree of both the polyvinyl alcohol (A) and the polyvinyl alcohol (B) is 2000 to 5000 because the above-described effects can be more remarkably exhibited.

  In the present invention, the degree of polymerization (P) refers to the viscosity average degree of polymerization, which is measured according to JIS K 6726 (1994), and is measured in water at 30 ° C. after completely re-saponifying and purifying PVA. From the intrinsic viscosity [η] (dL / g), it is obtained by the following formula (1).

Formula (1)
P = ([η] × 10 ³ /8.29) ^{(1 / 0.62)}

  The polyvinyl alcohol (B) contained in the low refractive index layer preferably has a saponification degree in the range of 75 to 90 mol% and a polymerization degree in the range of 2000 to 5000. When polyvinyl alcohol having such characteristics is contained in the low refractive index layer, it is preferable in that interfacial mixing is further suppressed. This is considered to be because there are few cracks of a coating film and set property improves.

It is preferable that two kinds of polyvinyl alcohols having different saponification degrees are used between layers having different refractive indexes.
For example, when polyvinyl alcohol (A) having a low saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a high saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained within a range of 40 to 100% by mass, more preferably within a range of 60 to 95% by mass, based on the total mass of all polyvinyl alcohols in the layer. The polyvinyl alcohol (B) is preferably contained within a range of 40 to 100% by mass, and more preferably within a range of 60 to 95% by mass with respect to the total mass of all polyvinyl alcohols in the low refractive index layer. When polyvinyl alcohol (A) having a high saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a low saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained within a range of 40 to 100% by mass, more preferably within a range of 60 to 95% by mass, based on the total mass of all polyvinyl alcohols in the layer. The polyvinyl alcohol (B) is preferably contained within a range of 40 to 100% by mass, and more preferably within a range of 60 to 95% by mass with respect to the total mass of all polyvinyl alcohols in the low refractive index layer.
When the content of the polyvinyl alcohol is 40% by mass or more, interlayer mixing is suppressed, and the effect that the disturbance of the interface is reduced appears significantly. On the other hand, if content is 100 mass% or less, stability of a coating liquid will improve.

(Other binder resins)
In the high refractive index layer, any first water-soluble binder resin other than polyvinyl alcohol can be used without limitation as long as the high refractive index layer containing the first metal oxide particles can form a coating film. Is possible. The same applies to the low refractive index layer described later. However, in view of environmental problems and flexibility of the coating film, water-soluble polymers (particularly gelatin, thickening polysaccharides, polymers having reactive functional groups) are preferable. These water-soluble polymers may be used alone or in combination of two or more.

  In the high refractive index layer, the content of other binder resins that can be used together with polyvinyl alcohol that is preferably used as the water-soluble binder resin is 5 to 50 mass with respect to 100 mass% of the solid content of the high refractive index layer. % Can also be used.

  As the water-soluble binder resin, it is not necessary to use an organic solvent, and it is preferable from the viewpoint of environmental conservation. Therefore, the water-soluble binder resin is preferably composed of a water-soluble polymer. If necessary, in addition to the polyvinyl alcohol and the modified polyvinyl alcohol, polyvinyl A water-soluble polymer other than alcohol and modified polyvinyl alcohol may be used as the water-soluble binder resin. The water-soluble polymer is the temperature at which the water-soluble polymer is most dissolved, and is filtered through a G2 glass filter (maximum pores 40 to 50 μm) when dissolved in water so that the concentration is 0.5% by mass. In this case, the mass of the insoluble matter separated by filtration is within 50% by mass of the added water-soluble polymer. Among such water-soluble polymers, the aforementioned gelatin, cellulose, thickening polysaccharide, or polymer having a reactive functional group can be preferably used. These water-soluble polymers may be used alone or in combination of two or more.

(First metal oxide particles)
As the first metal oxide particles applicable to the high refractive index layer, metal oxide particles having a refractive index in the range of 2.0 to 3.0 are preferable.
Specifically, titanium oxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, ferric oxide, iron Examples thereof include black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. In addition, composite oxide particles composed of a plurality of metals, core / shell particles whose metal structure changes into a core / shell shape, and the like can also be used.

  In order to form a transparent high refractive index layer having a higher refractive index, the high refractive index layer includes metal oxide particles having a high refractive index such as titanium and zirconium, that is, titanium oxide particles and / or zirconia oxide. It is preferable to contain particles. Among these, titanium oxide is more preferable from the viewpoint of the stability of the coating liquid for forming the high refractive index layer. Among titanium oxides, the rutile type (tetragonal system) has a lower catalytic activity than the anatase type, and the weather resistance of the high refractive index layer and adjacent layers is higher, and the refractive index is higher. To preferred.

  In addition, when core / shell particles are used as the first metal oxide particles in the high refractive index layer, the shell layer is such that the titanium oxide particles are core / shell particles coated with a silicon-containing hydrated oxide. This is preferable because the intermixing of the silicon-containing hydrated oxide and the first water-soluble binder resin suppresses interlayer mixing between the high refractive index layer and the adjacent layer.

  The aqueous solution containing titanium oxide particles used for the core of the core / shell particles is an aqueous solution in which the pH measured at 25 ° C. is in the range of 1.0 to 3.0 and the zeta potential of the titanium particles is positive. It is preferable to use a titanium oxide sol whose surface is made hydrophobic and dispersible in an organic solvent.

The content of the first metal oxide particles is preferably in the range of 15 to 80% by mass with respect to the solid content of 100% by mass of the high refractive index layer, whereby the refractive index with the low refractive index layer. A difference can be given. More preferably, it exists in the range of 20-77 mass%, More preferably, it exists in the range of 30-75 mass%.
The content of the metal oxide particles other than the core / shell particles in the high refractive index layer is not particularly limited as long as the effects of the present invention can be obtained.

The volume average particle diameter of the first metal oxide particles applied to the high refractive index layer is preferably 30 nm or less, more preferably in the range of 1 to 30 nm, and in the range of 5 to 15 nm. More preferably. A volume average particle size in the range of 1 to 30 nm is preferable in that the haze is small and the visible light transmittance is excellent.
The volume average particle diameter of the first metal oxide particles refers to a method of observing the particles themselves using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, or a cross section or surface of the refractive index layer. By observing the appearing particle image with an electron microscope, the particle diameters of 1000 arbitrary particles are measured, and particles having particle diameters of d ₁ , d ₂ ,..., D _k are respectively n ₁ , n _2. ,..., N _{k in} a group of particulate metal oxides, where the volume per particle is v ₁ , v ₂ ,..., V _k , respectively, the volume average particle diameter mv = {Σ ( v _i · d _i )} / {Σ (v _i )} is an average particle size weighted by a volume.

  Furthermore, the first metal oxide particles according to the present invention are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula (2) is 40% or less. This monodispersity is more preferably 30% or less, and particularly preferably in the range of 0.1 to 20%.

Formula (2)
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 (%)

(Core / shell particles)
As the first metal oxide particles applied to the high refractive index layer, it is preferable to use “titanium oxide particles surface-treated with a silicon-containing hydrated oxide”. It may be referred to as “core / shell particles” or “Si-coated TiO ₂ ”.

In the core / shell particles, the titanium oxide particles are coated with a silicon-containing hydrated oxide, and the average particle size of the core portion is preferably in the range of 1 to 30 nm, more preferably the average particle size is 4 to 4. The surface of the titanium oxide particles in the range of 30 nm is silicon-containing so that the coating amount of the silicon-containing hydrated oxide is 3 to 30% by mass as SiO _{2 with} respect to the titanium oxide as the core. It is the structure which the shell which consists of hydrated oxide of this coat | covered.

  That is, by containing the core / shell particles, the intermixing of the high refractive index layer and the low refractive index layer is caused by the interaction between the silicon-containing hydrated oxide of the shell layer and the first water-soluble binder resin. The effect of being suppressed and the effect of preventing problems such as deterioration of the binder and choking due to the photocatalytic activity of titanium oxide when titanium oxide is used as the core can be achieved.

The core / shell particles preferably have a coating amount of silicon-containing hydrated oxide in the range of 3 to 30% by mass as SiO _{2 with} respect to titanium oxide as a core, but more preferably 3 to 10%. It is in the range of mass%, more preferably in the range of 3-8 mass%. If the coating amount is 30% by mass or less, a high refractive index layer can be made to have a high refractive index, and if the coating amount is 3% by mass or more, core / shell particle particles can be stably formed. can do.

  The average particle diameter of the core-shell particles is preferably in the range of 1 to 30 nm, more preferably in the range of 5 to 20 nm, and still more preferably in the range of 5 to 15 nm. If the average particle diameter of the core-shell particles is in the range of 1 to 30 nm, optical properties such as near infrared reflectance, transparency, and haze can be further improved.

  The core / shell particles can be produced by a known method. For example, JP-A-10-158015, JP-A-2000-053421, JP-A-2000-063119, JP-A-2000- No. 204301, Japanese Patent No. 4550753 and the like can be referred to.

  The silicon-containing hydrated oxide applied to the core / shell particles may be either a hydrate of an inorganic silicon compound, a hydrolyzate or a condensate of an organosilicon compound. In the present invention, a compound having a silanol group It is preferable that

The high refractive index layer may contain other metal oxide particles in addition to the core / shell particles. When other metal oxide particles are used in combination, various ionic dispersants and protective agents can be used so that the core and shell particles described above do not aggregate in a chargeable manner.
Examples of metal oxide particles that can be used in addition to the core / shell particles include titanium dioxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, and yellow lead. Zinc yellow, chromium oxide, ferric oxide, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, tin oxide and the like.

  The core / shell particles may be those in which the entire surface of the titanium oxide particles that are the core is coated with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles that are the core is hydrated and oxidized with silicon. It may be coated with an object.

(Curing agent)
In order to cure the first water-soluble binder resin applied to the high refractive index layer, a curing agent can also be used.
The curing agent that can be used together with the first water-soluble binder resin is not particularly limited as long as it causes a curing reaction with the water-soluble binder resin. For example, when polyvinyl alcohol is used as the first water-soluble binder resin, boric acid and its salt are preferable as the curing agent. In addition to boric acid and its salts, known ones can be used, and in general, a compound having a group capable of reacting with polyvinyl alcohol or a compound that promotes the reaction between different groups possessed by polyvinyl alcohol. Select and use.
Specific examples of the curing agent include epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl-4- Glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glyoxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5,-) s-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

  Boric acid and its salts refer to oxygen acids and their salts having a boron atom as a central atom, specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid and octabored acid. Examples include acids, and salts thereof.

  Boric acid having a boron atom as a curing agent and a salt thereof may be used as a single aqueous solution or as a mixture of two or more. Particularly preferred is a mixed aqueous solution of boric acid and borax.

  The aqueous solutions of boric acid and borax can be added only as relatively dilute aqueous solutions, respectively, but by mixing both, a concentrated aqueous solution can be obtained and the coating solution can be concentrated. Moreover, there exists an advantage which can control the pH of the aqueous solution to add comparatively freely.

  Among them, the use of boric acid and salts thereof, or borax, facilitates formation of metal oxide particles and OH groups of water-soluble binder resin polyvinyl alcohol and hydrogen bonding network, resulting in high refractive index. Interlayer mixing between the layer and the low refractive index layer is suppressed, and a preferable near-infrared light blocking characteristic is considered to be achieved, which is more preferable.

The content of the curing agent in the high refractive index layer is preferably in the range of 1 to 10% by mass and in the range of 2 to 6% by mass with respect to 100% by mass of the solid content of the high refractive index layer. It is more preferable.
In particular, the total use amount of the curing agent when polyvinyl alcohol is used as the first water-soluble binder resin is preferably in the range of 1 to 600 mg per 1 g of polyvinyl alcohol, and more preferably in the range of 100 to 600 mg per 1 g of polyvinyl alcohol. preferable.

<Low refractive index layer>
The low refractive index layer contains at least a second water-soluble binder resin and second metal oxide particles, and if necessary, a curing agent, a surface coating component, a particle surface protective agent, a binder resin, a surfactant, Various additives may be included.
The refractive index of the low refractive index layer is preferably in the range of 1.10 to 1.60, more preferably 1.30 to 1.50.

(Second water-soluble binder resin)
As the second water-soluble binder resin applied to the low refractive index layer, polyvinyl alcohol is preferably used. Furthermore, it is more preferable that polyvinyl alcohol (B) different from the saponification degree of polyvinyl alcohol (A) present in the high refractive index layer is used in the low refractive index layer. In addition, description about polyvinyl alcohol (A) and polyvinyl alcohol (B), such as a preferable weight average molecular weight of 2nd water-soluble binder resin, is demonstrated in the water-soluble binder resin of a high refractive index layer, Here Omitted.

The content of the second water-soluble binder resin in the low refractive index layer is preferably within the range of 20 to 99.9% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably, it is in the range of mass%.
As the water-soluble binder resin other than polyvinyl alcohol that can be applied in the low refractive index layer, as described above, if the low refractive index layer containing the second metal oxide particles can form a coating film, what is it? Anything can be used without limitation.

  In the low refractive index layer, the content of other binder resin used in combination with polyvinyl alcohol preferably used as the second water-soluble binder resin is 0 to 10 mass relative to 100 mass% of the solid content of the low refractive index layer. % Can also be used.

  The low refractive index layer may contain water-soluble polymers such as celluloses, thickening polysaccharides, and polymers having reactive functional groups. These water-soluble polymers such as celluloses, thickening polysaccharides, and polymers having reactive functional groups are the same as the water-soluble polymers described in the high refractive index layer described above. Is omitted.

(Second metal oxide particles)
As the second metal oxide particles applied to the low refractive index layer, silica (silicon dioxide) is preferably used, and specific examples thereof include synthetic amorphous silica and colloidal silica. Among these, it is more preferable to use acidic colloidal silica sol, and it is more preferable to use colloidal silica sol dispersed in an organic solvent. In order to further reduce the refractive index, hollow particles having pores inside the particles can be used as the second metal oxide particles applied to the low refractive index layer, particularly silica (silicon dioxide). The hollow particles are preferred.

  The second metal oxide particles (preferably silicon dioxide) applied to the low refractive index layer preferably have an average particle size in the range of 3 to 100 nm. The average particle diameter of primary particles of silicon dioxide dispersed in a primary particle state (particle diameter in a dispersion state before coating) is more preferably in the range of 3 to 50 nm, and in the range of 3 to 40 nm. Is more preferably 3 to 20 nm, and most preferably within a range of 4 to 10 nm. Moreover, as an average particle diameter of secondary particle | grains, it is preferable at 30 points or less at the point which has few hazes and is excellent in visible light transmittance | permeability.

  The average particle size of the metal oxide particles applied to the low refractive index layer is determined by observing the particles themselves or the particles appearing on the cross section or surface of the refractive index layer with an electron microscope and measuring the particle size of 1000 arbitrary particles. The simple average value (number average) is obtained. Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

  The colloidal silica is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A 57-14091 and JP-A 60-219083, JP 60-218904, JP 61-20792, JP 61-188183, JP 63-17807, JP 4-93284, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142, JP-A Reference can be made to those described in JP-A-7-179029, JP-A-7-137431, WO94 / 26530, etc. Kill.

  Such colloidal silica may be a synthetic product or a commercially available product. The colloidal silica may be one whose surface is cation-modified, or may be one treated with Al, Ca, Mg, Ba or the like.

Hollow particles can also be used as the second metal oxide particles applied to the low refractive index layer. When hollow particles are used, the average particle pore size is preferably in the range of 3 to 70 nm, more preferably in the range of 5 to 50 nm, and still more preferably in the range of 5 to 45 nm. The average particle pore diameter of the hollow particles is the average value of the inner diameters of the hollow particles. If the average particle pore diameter of the hollow particles is within the above range, the refractive index of the low refractive index layer is sufficiently lowered.
The average particle diameter is 50 or more at random, which can be observed as an ellipse in a circular, elliptical or substantially circular shape by electron microscope observation. Is obtained. The average particle hole diameter means the minimum distance among the distances between the outer edges of the hole diameter that can be observed as a circle, an ellipse, or a substantially circle or ellipse, between two parallel lines.

  The second metal oxide particles may be surface-coated with a surface coating component. In particular, when metal oxide particles that are not in the form of a core / shell are used as the first metal oxide particles, the surface of the second metal oxide particles is coated with a surface coating component such as polyaluminum chloride. It becomes difficult to aggregate with metal oxide particles.

  The content of the second metal oxide particles in the low refractive index layer is preferably in the range of 0.1 to 70% by mass with respect to 100% by mass of the solid content of the low refractive index layer, and is preferably 30 to 70. The content is more preferably in the range of mass%, more preferably in the range of 45 to 65 mass%.

(Curing agent)
Similar to the high refractive index layer, the low refractive index layer can further contain a curing agent. The curing agent is not particularly limited as long as it causes a curing reaction with the second water-soluble binder resin contained in the low refractive index layer. In particular, as the curing agent when polyvinyl alcohol is used as the second water-soluble binder resin to be applied to the low refractive index layer, boric acid and a salt thereof, and / or borax are preferable. In addition to boric acid and its salts, known ones can be used.

The content of the curing agent in the low refractive index layer is preferably in the range of 1 to 10% by mass and in the range of 2 to 6% by mass with respect to 100% by mass of the solid content of the low refractive index layer. It is more preferable.
In particular, when polyvinyl alcohol is used as the second water-soluble binder resin, the total amount of the curing agent is preferably in the range of 1 to 600 mg per 1 g of polyvinyl alcohol, more preferably in the range of 100 to 600 mg per 1 g of polyvinyl alcohol. preferable.

  Specific examples of the curing agent and the like are the same as those of the above-described high refractive index layer, and thus description thereof is omitted here.

<Other additives for each refractive index layer>
Various additives can be used in the high refractive index layer and the low refractive index layer as necessary.
The content of the additive in each refractive index layer is preferably 0 to 20% by mass with respect to 100% by mass of the solid content of the high refractive index layer.
Additives applicable to the present invention will be described below.

(Surfactant)
At least one of the high refractive index layer and the low refractive index layer may contain a surfactant.
As the surfactant, any of zwitterionic, cationic, anionic, and nonionic types can be used. More preferably, a betaine zwitterionic surfactant, a quaternary ammonium salt cationic surfactant, a dialkylsulfosuccinate anionic surfactant, an acetylene glycol nonionic surfactant, or a fluorine cationic interface It is an activator.
The addition amount of the surfactant is within the range of 0.005 to 0.300 mass% when the total mass of the coating liquid for high refractive index layer or the coating liquid for low refractive index layer is 100 mass%. Is preferable, and it is more preferable to be within the range of 0.010 to 0.100 mass%.

(amino acid)
The high refractive index layer or the low refractive index layer may contain an amino acid having an isoelectric point of 6.5 or less. By including an amino acid, the dispersibility of the metal oxide particles in the high refractive index layer or the low refractive index layer is improved.

Here, the amino acid is a compound having an amino group and a carboxy group in the same molecule, and may be any type of amino acid such as α-, β-, and γ-. Some amino acids have optical isomers, but in the present invention, there is no difference in effect due to optical isomers, and any isomer can be used alone or in racemic form.
For a detailed explanation of amino acids, reference can be made to the description on pages 268 to 270 of the 1st edition of Chemistry Dictionary (Kyoritsu Shuppan: published in 1960).

  Specific examples of preferable amino acids include aspartic acid, glutamic acid, glycine, serine, and the like, and glycine or serine is particularly preferable.

  The isoelectric point of an amino acid means this pH value because an amino acid balances positive and negative charges in a molecule at a specific pH, and the overall charge becomes zero. The isoelectric point of each amino acid can be determined by isoelectric focusing at a low ionic strength.

(Emulsion resin)
The high refractive index layer or the low refractive index layer may further contain an emulsion resin. By including the emulsion resin, the flexibility of the film is increased and the workability such as sticking to glass is improved.
Emulsion resin is a resin in which fine resin particles with an average particle diameter of about 0.01 to 2.00 μm are dispersed in an emulsion in an aqueous medium, and an oil-soluble monomer having a hydroxy group. Obtained by emulsion polymerization using a molecular dispersant. There is no fundamental difference in the polymer component of the resulting emulsion resin depending on the type of dispersant used. Examples of the dispersant used in the polymerization of the emulsion include polyoxyethylene nonylphenyl ether in addition to low molecular weight dispersants such as alkylsulfonate, alkylbenzenesulfonate, diethylamine, ethylenediamine, and quaternary ammonium salt. And polymer dispersants such as polyoxyethylene lauric acid ether, hydroxyethyl cellulose, and polyvinylpyrrolidone.
When emulsion polymerization is performed using a polymer dispersant having a hydroxy group, the presence of hydroxy groups is estimated at least on the surface of fine particles, and emulsion resins polymerized using other dispersants are the chemical and physical properties of emulsions. The nature is different.

  The polymer dispersant containing a hydroxy group is a polymer dispersant having a weight average molecular weight of 10,000 or more, and having a hydroxy group substituted on the side chain or terminal. For example, polyacrylic acid soda, polyacrylamide Examples thereof include those obtained by copolymerizing 2-ethylhexyl acrylate with such an acrylic polymer, and polyethers such as polyethylene glycol and polypropylene glycol.

(Lithium compound)
At least one of the high refractive index layer and the low refractive index layer may contain a lithium compound. The coating liquid for the high refractive index layer or the coating liquid for the low refractive index layer containing the lithium compound becomes easier to control the viscosity, and as a result, the production stability when adding the optical film of the present invention to glass is further improved.

The lithium compound is not particularly limited. For example, lithium carbonate, lithium sulfate, lithium nitrate, lithium acetate, lithium orotate, lithium citrate, lithium molybdate, lithium chloride, lithium hydride, lithium hydroxide, lithium bromide , Lithium fluoride, lithium iodide, lithium stearate, lithium phosphate, lithium hexafluorophosphate, lithium aluminum hydride, lithium hydride triethylborate, lithium triethoxyaluminum hydride, lithium tantalate, hypochlorous acid Examples include lithium, lithium oxide, lithium carbide, lithium nitride, lithium niobate, lithium sulfide, lithium borate, LiBF ₄ , LiClO ₄ , LiPF ₄ , LiCF ₃ SO _{3 and the} like. These lithium compounds can be used alone or in combination of two or more.
Among these, lithium hydroxide is preferable from the viewpoint that the effects of the present invention can be sufficiently exhibited.

  The addition amount of the lithium compound is preferably in the range of 0.005 to 0.050 g, more preferably 0.010 to 0.030 g, per 1 g of metal oxide particles present in each refractive index layer.

(Other additives)
Other additives applicable to the high refractive index layer and the low refractive index layer include, for example, JP-A-57-74193, JP-A-57-87988, JP-A-62-261476, etc. Described in JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, Antifading agents, various anionic, cationic or nonionic surfactants described in, for example, Kaihei 3-13376, JP 59-42993 A, JP 59-52689 A, JP 62-280069 A , Whitening agent, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, carbonic acid, as described in JP-A-61-228771, JP-A-4-219266, etc. PH adjusters such as lithium, antifoaming agents, lubricants such as diethylene glycol, preservatives, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic Examples include various known additives such as particles, thickeners, lubricants, infrared absorbers, dyes, and pigments.

<Method for forming reflective layer laminate>
As a method for forming the reflective layer laminate, it is preferably formed by applying a wet coating method, and further includes at least a first water-soluble binder resin and first metal oxide particles on a transparent substrate. A production method including a step of wet-coating the coating solution for the high refractive index layer and the coating solution for the low refractive index layer containing at least the second water-soluble binder resin and the second metal oxide particles is preferable.
The wet coating method is not particularly limited, and examples thereof include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a slide type curtain coating method, US Pat. No. 2,761,419, and US Pat. No. 2,761791. Examples thereof include a slide hopper coating method and an extrusion coating method described in the specification and the like. In addition, as a method of applying a plurality of layers in a multilayer manner, a sequential multilayer application method or a simultaneous multilayer application method may be used.

<Polymer layer laminate>
The polymer layer laminate that is an embodiment of the near-infrared light shielding layer is configured by laminating a large number of first polymer layers and second polymer layers having different refractive indexes from the first polymer layer.

The first polymer layer and the second polymer layer are alternately laminated to form a polymer layer laminate.
Examples of the polymer material constituting the first and second polymer layers include polyester, acrylic, a blend or copolymer of polyester acrylic, and examples thereof include polyethylene-2,6-naphthalate (PEN), naphthalene dicarboxylic copolyester (coPEN). , Polymethyl methacrylate (PMMA), polybutylene-2,6-naphthalate (PBN), polyethylene terephthalate (PET), naphthalene dicarboxylic acid derivative, diol copolymer, polyetheretherketone, syndiotac polystyrene resin (SPS) and the like. Specific combinations of the first polymer layer and the second polymer layer include combinations of PEN / PMMA, PET / PMMA, PEN / coPEN, PEN / SPS, PET / SPS, and the like. Can.

As a specific configuration example of the polymer layer laminate, as described with reference to FIG. 9, two types of polymer films having different materials are laminated. Specifically, as shown in FIG. 9, from the transparent substrate side, PEN ₁ formed of a polyethylene naphthalate film, PMMA ₁ , PEN ₂ , PMMA ₂ , PEN formed of a polymethyl methacrylate film ₃ , PMMA ₃ ,..., PMMA _m−1 , PEN _m , PMMA _m , PEN _{m + 1} are laminated to form a polymer layer laminate ML2.

  The total number of films to be laminated is not particularly limited, but is preferably in the range of about 150 to 1000 layers.

<Method for forming polymer layer laminate>
As a method for forming the polymer layer laminate, a known film forming method such as a wet coating method or a vacuum deposition method can be applied, and it is preferably formed by a wet coating method from the viewpoint of manufacturing cost.

  For details of these polymer layer laminates, the contents described in US Pat. No. 6,049,419 can be referred to.

  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 "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

"Preparation of VO _2-containing particles"
<Preparation of VO ₂ containing particles 101>
0.9 g of divanadium pentoxide (V ₂ O ₅ , Wako Pure Chemical Industries, special grade) is added to 30 ml of a 10 mass% aqueous solution of hydrogen peroxide (concentration 35 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) After stirring for 4 hours, a clear reddish brown sol was obtained.
To the obtained sol, a 5% by mass aqueous solution of hydrazine monohydrate (N ₂ H ₄ .H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added at a molar ratio of 0.49 (divanadium pentoxide). An amount corresponding to an equivalent ratio value of 0.98) was slowly added dropwise.
After dripping, the reaction liquid stirred for 60.0 minutes is a commercially available autoclave for hydrothermal reaction treatment (manufactured by Sanai Kagaku Co., HU-50 type) (SUS body with a 50 ml capacity Teflon (registered trademark) inner cylinder). And hydrothermal reaction at 270 ° C. for 48 hours.
Next, the obtained reaction solution was filtered, and the residue was washed with water and ethanol. Further, this residue was dried at 60 ° C. for 10 hours using a constant temperature dryer to produce VO ₂ -containing particles 101.

<Preparation of VO _2-containing particles 102 to 107>
In the production of the VO ₂ -containing particles 101, except that the molar ratio (equivalent ratio) of hydrazine monohydrate to divanadium pentoxide was changed as shown in Table 1, the VO ₂ -containing particles 102- 107 was produced.

<Preparation of VO _2-containing particles 108 to 111>
In the production of the VO ₂ -containing particles 103, VO ₂ -containing particles 108 to 111 were produced in the same manner except that the stirring time after addition of the reducing agent was changed as shown in Table 1.

<Preparation of VO _2-containing particles 112 to 114>
In the production of the VO ₂ -containing particles 103, the VO ₂ -containing particles 112 to 114 were produced in the same manner except that the liquid temperature of the reaction solution during the hydrothermal reaction was changed as shown in Table 1.

<Preparation of VO _2-containing particles 115 to 118>
In the production of the VO ₂ -containing particles 103, VO ₂ -containing particles 115 to 118 were produced in the same manner except that the hydrothermal reaction time was changed as shown in Table 1.

<Preparation of VO ₂ -containing particles 119>
In 30 ml of pure water, a 5% by mass aqueous solution of hydrazine monohydrate (N ₂ H ₄ · H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd.) has a molar ratio with respect to divanadium pentoxide of 0.98 (equivalent The amount of the ratio 1.96) was added dropwise, and 0.9 g of divanadium pentoxide (V ₂ O ₅ , Wako Pure Chemical Industries, Special Grade) was further added to prepare a reaction solution.
After the preparation, the reaction solution stirred for 60.0 minutes is a commercially available autoclave for hydrothermal reaction treatment (manufactured by Sanai Kagaku Co., HU-50 type) (SUS body is equipped with a 50 ml capacity Teflon (registered trademark) inner cylinder). And hydrothermal reaction at 270 ° C. for 48 hours.
Next, the obtained reaction solution was filtered, and the residue was washed with water and ethanol. Furthermore, this residue was dried at 60 ° C. for 10 hours using a constant temperature dryer to produce VO ₂ -containing particles 119.

<Preparation of VO ₂ containing particles 120>
In the production of the VO ₂ -containing particles 119, the VO ₂ -containing particles 120 were prepared in the same manner except that the molar ratio (equivalent ratio) of hydrazine monohydrate to divanadium pentoxide was changed as shown in Table 1. Produced.

<Preparation of VO ₂ containing particles 121>
0.9 g of divanadium pentoxide (V ₂ O ₅ , Wako Pure Chemical Industries, special grade) is added to 30 ml of a 10 mass% aqueous solution of hydrogen peroxide (concentration 35 mass%, manufactured by Wako Pure Chemical Industries, Ltd.) After stirring for 4 hours, a clear reddish brown sol was obtained.
To the obtained sol, a 5% by mass aqueous solution of oxalic acid (H ₂ C ₂ O ₄ , manufactured by Wako Pure Chemical Industries, Ltd.) has a molar ratio with respect to divanadium pentoxide of 0.75 (equivalent ratio of 0). .75) was slowly added dropwise.
After dripping, the reaction liquid stirred for 60.0 minutes is a commercially available autoclave for hydrothermal reaction treatment (manufactured by Sanai Kagaku Co., HU-50 type) (SUS body with a 50 ml capacity Teflon (registered trademark) inner cylinder). And hydrothermal reaction at 270 ° C. for 48 hours.
Next, the obtained reaction solution was filtered, and the residue was washed with water and ethanol. Furthermore, this residue was dried at 60 ° C. for 10 hours using a constant temperature dryer to produce VO ₂ -containing particles 121.

<Preparation of VO ₂ -containing particles 122>
In the production of the VO ₂ -containing particles 121, the VO ₂ -containing particles 122 were produced in the same manner except that the molar ratio (equivalent ratio) of oxalic acid to divanadium pentoxide was changed as shown in Table 1.

<Preparation of VO ₂ containing particles 123>
To 30 ml of pure water, 1.3 g of ammonium vanadate (NH ₄ VO ₃ , manufactured by Wako Pure Chemical Industries, special grade) is mixed, and further hydrazine monohydrate (N ₂ H ₄ · H ₂ O, Wako Pure Chemical Industries, Ltd.). A 5% by mass aqueous solution (manufactured, special grade) was slowly added dropwise in such an amount that the molar ratio with respect to ammonium vanadate was 0.76 (equivalent ratio value 1.52).
After dripping, the reaction liquid stirred for 60.0 minutes is equipped with a commercially available autoclave for hydrothermal reaction treatment (HU-50 type, manufactured by Sanai Kagaku Co., Ltd.) (SUS body with a 50 ml capacity Teflon (registered trademark) inner cylinder). ) And hydrothermal reaction at 270 ° C. for 48 hours.
Next, the obtained reaction solution was filtered, and the residue was washed with water and ethanol. Furthermore, this residue was dried at 60 ° C. for 10 hours using a constant temperature dryer to produce VO ₂ -containing particles 123.

<Preparation of VO ₂ containing particles 124>
In the production of the VO ₂ -containing particles 123, the VO ₂ -containing particles 124 were produced in the same manner except that the molar ratio (equivalent ratio) of hydrazine monohydrate to ammonium vanadate was changed as shown in Table 1. did.

<Preparation of VO ₂ containing particles 125>
Purified water 30 ml, ammonium vanadate _(NH 4 VO _3, manufactured by Wako Pure Chemical Industries, Ltd., special grade) 1.3 g, ammonium tungstate para pentahydrate _{((NH 4) 10 W 12} O 4 · 5H 2 O, the sum 0.029 g (manufactured by Kojun Pharmaceutical Co., Ltd.) was mixed, and a 5% by mass aqueous solution of hydrazine monohydrate (N ₂ H ₄ · H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added in a molar ratio to ammonium vanadate Was slowly dripped in an amount such that the value of 0.30 (equivalent ratio value 0.60).
After dripping, the reaction liquid stirred for 60.0 minutes is equipped with a commercially available autoclave for hydrothermal reaction treatment (HU-50 type, manufactured by Sanai Kagaku Co., Ltd.) (SUS body with a 50 ml capacity Teflon (registered trademark) inner cylinder). ) And hydrothermal reaction at 270 ° C. for 48 hours.
Next, the obtained reaction solution was filtered, and the residue was washed with water and ethanol. Furthermore, this residue was dried at 60 ° C. for 10 hours using a constant temperature dryer to produce VO ₂ -containing particles 125.

<Preparation of VO ₂ -containing particles 126>
In the production of the VO ₂ -containing particles 125, the VO ₂ -containing particles 126 were produced in the same manner except that the molar ratio (equivalent ratio) of hydrazine monohydrate to ammonium vanadate was changed as shown in Table 1. did.

<Evaluation>
(1) Measurement of pH of reaction solution after hydrothermal reaction In preparation of each VO ₂ -containing particle, the pH of the reaction solution after hydrothermal reaction (converted to 25 ° C.) was measured with a pH meter (Five Easy Plus manufactured by METTLER TOLEDO). It was measured using FEP20).
The measurement results are shown in Table 1.

(2) Evaluation of thermochromic properties In the preparation of each VO ₂ -containing particle, a reaction solution after hydrothermal reaction diluted 5000 times with pure water was used as a commercially available quartz cell with a stopper (two-sided translucent 45 mm × 12.5 mm). The transmission spectrum of the reaction solution was measured with a spectrophotometer that can be heated (V-670 model, manufactured by JASCO Corporation, 190-2500 nm). The measurement temperature was 20 ° C. and 80 ° C., and the temperature dependence of the light transmittance (wavelength 1300 nm) of the reaction solution was measured. The change (difference) in light transmittance due to the temperature rising from 20 ° C. to 80 ° C. at a wavelength of 1300 nm was calculated, and thermochromic properties were evaluated.
The evaluation results are shown in Table 1.

(3) VO ₂ each VO ₂ containing particles prepared composition and the number of valence measurements containing particles, a powder XRD apparatus (manufactured by Rigaku Corporation, RINT-TTR2) was used to measure the composition and valence.
Further, from the X-ray diffraction pattern obtained by XRD, by comparing the peak area derived from M phase VO _{2 with} the peak area derived from other vanadium compounds, the M phase VO _{2 in} the VO ₂ containing particles The percentage was calculated.
The measurement results are shown in Table 1.

In Table 1, “VO ₂ (M)” represents monoclinic VO ₂ -containing particles, and “VO ₂ (T)” represents tetragonal VO ₂ -containing particles. ing.

(4) Summary Table from 1 Obviously, VO ₂ containing particles produced by the production method of the present invention, as compared to VO ₂ containing particles of Comparative Example, it can be seen that excellent thermochromic.
From the above, the method for producing VO ₂ -containing particles in which the reaction solution having the equivalent ratio of the reducing agent to the vanadium compound in the range of 1.00 to 1.40 is hydrothermally reacted is highly pure and thermochromic. It was confirmed that the composition was useful for providing vanadium dioxide-containing particles having excellent properties.

First optical film 2 transparent substrate 3 optical function layer 3a resin 3b VO ₂ containing particles 4 near infrared light-shielding layer ML1, ML1a, ML1b reflecting layer stack ML2 polymeric layer laminate _{PEN 1 ~PEN m +} 1 polyethylene naphthalate film PMMA ₁ ～PMMA _m polymethyl methacrylate film _{T 1 ~T n, Ta 1 ~Ta} n, Tb 1 ~Tb n infrared reflective layer

Claims (9)

A method for producing vanadium dioxide-containing particles containing vanadium dioxide having thermochromic properties,
By hydrothermally reacting a reaction solution containing a raw material containing a vanadium compound, a reducing agent, and water, and having an equivalent ratio of the reducing agent to the vanadium compound within a range of 1.00 to 1.40. The method for producing vanadium dioxide-containing particles, wherein the vanadium dioxide-containing particles are formed.   2. The method for producing vanadium dioxide-containing particles according to claim 1, wherein the pH of the reaction solution after hydrothermal reaction (in terms of 25 ° C.) is in the range of 4.0 to 7.0.   The method for producing vanadium dioxide-containing particles according to claim 1 or 2, wherein the stirring time after addition of the reducing agent is 1 to 200 minutes.   The method for producing vanadium dioxide-containing particles according to any one of claims 1 to 3, wherein a liquid temperature of the reaction liquid during a hydrothermal reaction is set in a range of 250 to 350 ° C. .   The method for producing vanadium dioxide-containing particles according to any one of claims 1 to 4, wherein the hydrothermal reaction time is 12 to 72 hours.   The reaction solution is a compound containing at least one atom selected from the group consisting of tungsten, molybdenum, niobium, tantalum, tin, rhenium, iridium, osmium, ruthenium, germanium, chromium, iron, gallium, aluminum, fluorine and phosphorus. The method for producing vanadium dioxide-containing particles according to any one of claims 1 to 5, wherein the vanadium dioxide-containing particles are contained. A vanadium dioxide-containing particle produced by the method for producing a vanadium dioxide-containing particle according to any one of claims 1 to 6,
Vanadium dioxide-containing particles characterized by containing at least vanadium dioxide and having thermochromic properties.   A dispersion comprising the vanadium dioxide-containing particles according to claim 7. An optical film having an optical functional layer containing at least a resin on a transparent substrate,
The optical functional layer contains the vanadium dioxide-containing particles according to claim 7.

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