JP2012242224A - Measuring method of hardening rate of dimming film, manufacturing method for dimming film, and dimming film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method of a hardening rate of a resin matrix in a dimming film having excellent swiftness and simplicity.SOLUTION: A method for measuring a hardening rate of a resin matrix by near-infrared spectroscopy in a dimming film is provided. The dimming film is formed by clamping a dimming layer between two transparent conductive resin substrates, the dimming layer including the resin matrix which is a hardened material of a polymer medium, and a light adjusting suspension dispersed in the resin matrix. When interference fringes are formed by transmitting the near-infrared light to the dimming film, the near-infrared spectrum is measured using a second dimming film including two transparent conductive resin substrates satisfying the following expression (I). The expression (I): (Ry)≥λ×1/2, where (Ry) is the maximum height of the surface roughness in the irradiation area of the near-infrared light and λ is the wavelength of the interference fringe.

Description

  The present invention relates to a method for measuring a curing rate of a light control film, a method for manufacturing a light control film, and a light control film.

  The light control glass containing the light control suspension was first invented by Edwin. Land, and its form is between two transparent conductive resin substrates with a narrow spacing, It has a structure in which a liquid state light control suspension is injected (see, for example, Patent Document 1).

According to Edwin Land's invention, the liquid light control suspension injected between the two transparent conductive resin substrates is dispersed in the suspension when no electric field is applied. Due to the Brownian motion of the light conditioning particles, most of the incident light is reflected, scattered or absorbed by the light conditioning particles, and only a small portion is transmitted. Further, when an electric field is applied to the light control glass, an electric field is formed in the light adjustment suspension through the transparent conductive substrate, and the light adjustment particles representing the light adjustment function are polarized and arranged in parallel to the electric field. Light is transmitted between the adjusting particles and the light adjusting particles, and finally the light control glass becomes transparent.
That is, the degree of transmission, reflection, scattering, or absorption is determined by the shape, properties, concentration, and amount of light energy applied to the light control particles dispersed in the light control suspension.

  However, such an initial light control device is practically agglomeration of light control particles in a light control suspension, sedimentation due to its own weight, hue change due to heat, change in optical density, deterioration due to ultraviolet irradiation, base material However, it was difficult to put it to practical use because it was difficult to maintain the interval and to inject the light adjusting suspension into the interval.

  Robert L. Saxe, FC Lowell, and R. I. Thompson are the initial problems with dimming windows: Discloses a light control window using a light control glass supplemented with aggregation and sedimentation of light control particles, changes in optical density, and the like (see, for example, Patent Document 2). In this patent, etc., the density of the light adjusting particles and the suspending agent in the liquid state light adjusting suspension composed of the acicular light adjusting particles, the suspension for dispersing the light adjusting particles, the dispersion adjusting agent and the stabilizer, etc. In order to prevent the light adjustment particles from aggregating by adding a dispersion adjusting agent to improve the dispersibility of the light adjustment particles while preventing the precipitation of the light adjustment particles. Yes.

  However, these light control glasses also have a structure in which a liquid light control suspension is sealed in the gap between two transparent conductive resin base materials, as in the case of conventional light control glasses. When manufacturing a product with a larger size, it is difficult to enclose a uniform suspension in the gap between the two transparent conductive resin base materials, and the lowering phenomenon tends to occur due to the difference in water pressure between the upper and lower parts of the product. In addition, since the interval between the substrates changes due to the external environment, for example, wind pressure, as a result, the optical density changes and the hue becomes inhomogeneous, or the liquid is accumulated between the transparent conductive resin substrates. There is a problem that the surrounding sealing material is broken and the light adjusting material leaks. Further, the response time varies due to deterioration due to ultraviolet rays and a voltage drop between the peripheral portion and the central portion of the transparent conductive resin substrate.

  As a method for improving this, a liquid light control suspension is mixed with a curable polymer resin solution, and a phase separation method by polymerization, a phase separation method by solvent volatilization, or a phase separation method by temperature is used. A method of manufacturing a film has been proposed (see, for example, Patent Document 3).

US Pat. No. 1,955,923 US Pat. No. 3,756,700 JP 2002-189123 A

  The curable polymer medium enclosed in the gap between the two transparent conductive resin substrates is used in a cured state in the final product form. For example, when a curable polymer medium is cured with ultraviolet rays, the curing rate depends on various factors such as the irradiation amount of ultraviolet rays, the type of gas in the curing atmosphere, the flow rate, and the curing temperature. Therefore, it is necessary to optimize each of these factors when curing a curable polymer medium. However, until now, the curing rate of the polymer medium in the light control film cannot be appropriately measured, and it has been difficult to determine an index for evaluating reliability.

  Then, the subject of this invention is providing the measuring method of the hardening rate of the resin matrix in a light control film excellent in quickness and simplicity, the manufacturing method of a light control film using this measuring method, and a light control film. There is.

  Since the light control film is generally produced by a roll to roll method, the light control layer is obtained in a state where the light control layer is sandwiched between two transparent conductive resin substrates. Therefore, it is desirable to accurately measure the curing rate of the polymer medium while the transparent conductive resin substrate is attached. Since it is desired to improve the adhesion between the transparent conductive resin substrate and the light control layer, it is difficult to remove the transparent conductive resin substrate. Therefore, the method for measuring the curing rate of the resin matrix is inferior in speediness and simplicity.

Here, as a method of measuring the curing rate of the resin matrix contained in the light control layer while the light control layer is sandwiched between two transparent conductive resin base materials, the curing rate by infrared spectroscopy is used. A measurement method can be considered. However, in the infrared region from 400 cm ^-1 4000 cm ^-1, the absorption peak of the number of materials constituting the light control film, will overlap with the absorption peak derived from an acrylic group, an acryl group derived from the uncured (polymerizable Group) absorption peak is difficult to measure.

  A cure rate measurement method using Raman spectroscopy is also conceivable, but it is difficult to measure the cure rate because the entire spectrum is broad and unscattered by the light control particles contained in the light control layer. It is.

  Furthermore, when the curing rate is measured in a state where the light control layer is sandwiched between the two transparent conductive resin base materials, interference of incident light occurs by the transparent conductive resin base material, and the interference fringes overlap the measurement spectrum. For this reason, it became clear that the increase or decrease in the absorption peak derived from the polymerizable group could not be discriminated.

Based on the above situation, as a result of intensive studies by the inventors, it has been found that the above problem can be solved by using near infrared spectroscopy. In particular, interference fringes can be suppressed by appropriately setting the surface roughness of the transparent conductive resin base material in the region irradiated with near infrared light, and the curing rate of the resin matrix can be measured appropriately. I found out that I can.
Therefore, the present invention is as follows.

<1> A light control layer comprising a light control layer comprising a resin matrix which is a cured product of a polymer medium and a light control suspension dispersed in the resin matrix, sandwiched between two transparent conductive resin substrates. In the film, the curing rate of the resin matrix is a method of measuring by near infrared spectroscopy,
When interference fringes occur when near-infrared light is transmitted through the light control film, a near-red light is obtained using a second light control film provided with two transparent conductive resin substrates that satisfy the following formula (I). A method for measuring a curing rate of a resin matrix in a light control film, which measures an outer spectral spectrum.
Formula (I):
Maximum height (Ry) of surface roughness in the irradiation region of the near infrared light ≧ wavelength λ × 1/2 of the interference fringes

<2> The surface of the two transparent conductive resin substrates in the region irradiated with the near infrared light is dissolved by a solvent capable of dissolving the transparent conductive resin substrate, and the formula (I) The measuring method of the curing rate of the light control film as described in said <1> which processes the surface of the said transparent conductive resin base material so that it may satisfy | fill.

<3> The method for measuring a curing rate of a light control film according to <2>, wherein the solvent is hexafluoroisopropanol when the two transparent conductive resin base materials are made of polyethylene terephthalate.

<4> Measurement of the curing rate of the light control film according to any one of <1> to <3>, in which the near infrared light is incident on the surface of the light control film at 30 to 60 °. Method.

<5> A first light-controlling layer including a resin matrix that is a cured product of a polymer medium and a light-controlling suspension dispersed in the resin matrix, sandwiched between two transparent conductive resin substrates Producing a light control film;
When interference fringes are generated when the near-infrared light is transmitted through the first light control film, a second light control film including two transparent conductive resin substrates satisfying the following formula (I) A step of producing
A step of transmitting near infrared light to the second light control film to measure a near infrared spectrum, and measuring a curing rate of the resin matrix in the second light control film;
Applying the curing rate obtained by the measurement to the previously determined relationship between the curing condition and the curing rate of the polymer medium, the curing condition of the polymer medium that falls within a predetermined curing rate range The process of deriving
A dimming layer comprising a resin matrix obtained by curing the polymer medium under the derived curing conditions, and a light control suspension dispersed in the resin matrix is formed of two transparent conductive resin substrates. Producing a sandwiched third light control film;
The manufacturing method of the light control film which has these.
Formula (I):
Maximum height (Ry) of surface roughness in the irradiation region of the near infrared light ≧ wavelength λ × 1/2 of the interference fringes

<6> In the step of producing the second light control film, a solvent capable of dissolving the transparent conductive resin base material on the surface of the two transparent conductive resin base materials of the first light control film. The manufacturing method of the light control film as described in said <5> which melt | dissolves the area | region irradiated with the said near-infrared light, and processes the surface of the said transparent conductive resin base material so that the said Formula (I) may be satisfy | filled.

<7> The method for producing a light control film according to <6>, wherein when the two transparent conductive resin base materials are made of polyethylene terephthalate, the solvent is hexafluoroisopropanol.

<8> In the step of measuring the curing rate, any one of the above <5> to <7>, wherein the near infrared light is incident on the surface of the second light control film at 30 to 60 °. The manufacturing method of the light control film as described in 1 ..

<9> The method for producing a light control film according to any one of <5> to <8>, wherein the predetermined curing rate is 75 to 100%.

<10> The polymer medium has a polysiloxane structure having a (meth) acryloyl group, and the number of repeating units having the (meth) acryloyl group is 1.3 to 5.0% by mass of the total number of repeating units. The manufacturing method of the light control film of any one of said <5>-<9>.

<11> The method for producing a light control film according to any one of <5> to <10>, wherein the polymer medium has a weight average molecular weight of 35,000 to 60,000.

<12> Two transparent conductive resin base materials;
A light control layer including a resin matrix, which is a cured product of a polymer medium, sandwiched between the two transparent conductive resin substrates, and a light control suspension dispersed in the resin matrix; ,
The polymer medium has a polysiloxane structure having a (meth) acryloyl group, and the number of repeating units having the (meth) acryloyl group is 1.3 to 5.0% by mass of the total number of repeating units,
The light control film whose cure rate of the said resin matrix obtained by the measuring method of the cure rate of any one of said <1>-<4> is 75 to 100%.

  ADVANTAGE OF THE INVENTION According to this invention, the measuring method of the hardening rate of the resin matrix in a light control film excellent in quickness and simplicity can be provided. Moreover, the manufacturing method of the light control film excellent in manufacture control can be provided by using the measuring method of this hardening rate. Furthermore, the light control film excellent in heat resistance can be provided by using the measuring method of this hardening rate.

It is a schematic sectional drawing which shows the one aspect | mode of the light control film concerning this invention. 2A is a schematic cross-sectional view for explaining the operation when the electric field of the light control film of FIG. 1 is not applied, and FIG. 2B is a liquid state when the electric field is not applied. It is a figure which shows the mode of the droplet 3 of this light adjustment suspension liquid. 3A is a schematic cross-sectional view for explaining the operation when the electric field of the light control film of FIG. 1 is applied, and FIG. 3B is a liquid state when the electric field is applied. It is a figure which shows the mode of the droplet 3 of this light adjustment suspension liquid. It is a schematic sectional drawing for demonstrating an example of the state of the edge part of the light control film concerning this invention. It is a figure explaining maximum height Ry which is one of the indices of surface roughness. It is a flowchart which shows the procedure of an example of the manufacturing method of the light control film of this invention. It is a graph which shows the relationship between the irradiation amount of the ultraviolet-ray in Example 2, 5-8, and Comparative Examples 3 and 4, and the hardening rate measured by the method of this invention.

In the present invention, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes.
In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
Further, in the present specification, (meth) acryloyl group means at least one of acryloyl group and methacryloyl group, (meth) acrylate means at least one of acrylate and methacrylate, and (meth) acrylic acid means acrylic acid. And at least one of methacrylic acid.

In the present invention, a light control layer including a resin matrix that is a cured product of a polymer medium and a light control suspension dispersed in the resin matrix is sandwiched between two transparent conductive resin substrates. The present invention relates to a method for measuring a curing rate of the resin matrix in a light control film.
First, a light control film as a measurement target will be described, and then a method for measuring the curing rate of the resin matrix in the light control layer of the light control film will be described. And the manufacturing method of the light control film using this measuring method of a cure rate is demonstrated.

<Light control film>
The light control film of the present invention has two transparent conductive resin base materials (hereinafter sometimes referred to as “base materials”) and a light control layer sandwiched between the two base materials. The light control layer includes a resin matrix and a light control suspension dispersed in the resin matrix.

  The light control layer can generally be formed using a light control material. The light-modulating material contains a polymer medium that cures when irradiated with energy rays, and a light-conditioning suspension that is dispersed in the dispersion medium in a state in which the light-adjusting particles can flow. The light adjusting particles contained in the light adjusting suspension are preferably rod-shaped or needle-shaped.

  After the light control material is applied between the two transparent conductive resin base materials, the polymer medium in the light control material is cured, whereby light adjustment suspension is formed in the cured resin matrix. A light control layer in which the turbid liquid is dispersed is formed.

  As described above, in the light control layer of the light control film, the liquid light control suspension is dispersed in the form of fine droplets in the solid resin matrix in which the polymer medium is cured. Therefore, it is preferable that the polymer medium in the light control suspension can be phase-separated from the polymer medium and a cured product thereof.

  Here, in FIG. 1, an embodiment of the light control film of the present invention is shown as a structural schematic diagram. In the light control film shown in FIG. 1, the light control layer 1 is sandwiched between two sheets of a transparent conductive resin substrate 4 made of a transparent resin substrate 5b coated with a transparent conductive film 5a. A primer layer 6 is provided between the light control layer 1 and the transparent conductive resin substrate 4.

  The light control layer 1 includes a film-like resin matrix 2 in which a polymer medium is cured, and a liquid light-conditioning suspension dispersed in the form of droplets 3 in the resin matrix 2. In the droplet 3 of the light adjustment suspension, the light adjustment particles 10 are dispersed in the dispersion medium 9 (see FIG. 2B and the like).

  The light control film connects or disconnects the power source 7 and the two transparent conductive films 5 a by switching the switch 8.

  FIG. 2A is a schematic cross-sectional view for explaining the operation of the light control film shown in FIG. 1, and shows a state where the switch 8 is turned off and no electric field is applied. In this state, the light adjusting particles 10 dispersed in the droplet 3 are each directed in a random direction by Brownian motion as shown in FIG. Therefore, the incident light 11 is absorbed, scattered or reflected by the light adjusting particles 10 and cannot be transmitted.

  On the other hand, Fig.3 (a) is a schematic sectional drawing for demonstrating the action | operation of the state in which the electric field of the light control film of FIG. 1 is applied. As shown in FIG. 3A, when an electric field is applied by connecting the switch 8, the light adjusting particles 10 having an electric dipole moment are arranged in parallel with the electric field formed by the applied electric field. Therefore, the incident light 11 passes between the arranged light adjusting particles 10. In this way, the droplet 3 is converted to a transparent state with respect to the incident light, and the incident light is transmitted in a state where there is almost no scattering due to the viewing angle or a decrease in transparency. In order to increase the light transmittance in the transparent state and the sharpness in the colored state, the refractive index of the liquid light-adjusting suspension dispersed in the form of the droplet 3 and the resin matrix 2 It is preferable that the refractive indexes of these are matched.

  Hereinafter, each layer structure of the light control film of this invention is demonstrated.

[Transparent conductive resin substrate]
As a transparent conductive resin base material, a transparent conductive film (film such as ITO, SnO ₂ , In ₂ O ₃ , organic conductive film) having a light transmittance of 80% or more is generally coated on the transparent resin base material. A transparent conductive resin substrate having a surface resistance value of 3 to 3000Ω can be used. In addition, the light transmittance of a transparent resin base material can be measured based on the measuring method of the total light transmittance of JISK7105. Moreover, as a transparent resin base material, a polymer film etc. can be used, for example.

  Examples of the polymer film include polyester films such as polyethylene terephthalate (PET), polyolefin films such as polypropylene, polyvinyl chloride, acrylic resin films, polyether sulfone films, polyarylate films, and polycarbonate films. The polyethylene terephthalate film is preferable because it is excellent in transparency and excellent in moldability, adhesiveness, workability, and the like.

  The thickness of the transparent conductive film coated on the transparent resin substrate is preferably 10 to 5,000 nm, and the thickness of the transparent resin substrate is not particularly limited. For example, in the case of a polymer film, 10 to 200 μm is preferable.

  A transparent resin in which a transparent insulating substrate having a thickness of several nm to 1 μm is formed on a transparent conductive film in order to prevent a short-circuit phenomenon caused by mixing of different substances, etc. A conductive resin substrate may be used. When the light control film of the present invention is used for a reflection type light control window (for example, a rear view mirror for automobiles), a thin film made of a conductive metal such as aluminum, gold, or silver which is a reflector is used as an electrode. May be used directly.

[Primer layer]
The light control film of this invention may be equipped with the primer layer for improving the adhesiveness of a light control layer and a base material. The primer layer is provided on the surface of the base material facing the light control layer. The primer layer may be provided only on one base material or may be provided on both base materials.

  The primer layer includes a material containing a urethane acrylate containing a pentaerythritol skeleton, a material containing a (meth) acrylate having a hydroxyl group in the molecule, a material in which metal oxide fine particles are dispersed in an organic binder resin, The thin film is preferably formed of a phosphate ester having one or more polymerizable groups, a silane coupling agent having an amino group, or the like.

  The primer treatment (formation of the primer layer) of the transparent conductive resin substrate in the present invention includes, for example, a material for forming the primer layer, a bar coater method, a Mayer bar coater method, an applicator method, a doctor blade method, a roll coater method, A transparent conductive resin group using a die coater method, a comma coater method, a gravure coating method, a micro gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method, etc. alone or in combination. This can be done by applying to the material.

  In addition, when apply | coating, you may dilute with a suitable solvent as needed, and you may use the solution of the material which forms a primer layer. When a solvent is used, drying is required after coating on the transparent conductive resin substrate. In addition, the coating film used as a primer layer may be formed only on one side (transparent conductive film side) of the transparent conductive resin base material as necessary, or may be formed on both sides by an impregnation method or a dip coating method. .

  The solvent used for forming the primer layer may be any solvent that dissolves or disperses the material forming the primer layer and can be removed by drying or the like after forming the primer layer. Isopropyl alcohol, ethanol, methanol, 1-methoxy-2-propanol 2-methoxyethanol, cyclohexanone, methyl isobutyl ketone, anisole, methyl ethyl ketone, acetone, tetrahydrofuran, toluene, heptane, cyclohexane, ethyl acetate, propylene glycol monomethyl ether acetate, diethyl diglycol, dimethyl diglycol, isoamyl acetate, hexyl acetate, etc. These solvents can be used.

[Light control layer]
The light control layer in the present invention is formed by using a light control material including a resin matrix and a light control suspension dispersed in the resin matrix. The resin matrix is a cured product of a polymer medium, and the light adjustment suspension is a dispersion in a dispersion medium in a state where the light adjustment particles can flow. As the polymer medium and the dispersion medium (dispersion medium in the light control suspension), those in which the polymer medium and its cured product and the dispersion medium can be phase-separated at least when they are formed into a film are used. It is preferable to use a combination of an incompatible or partially compatible polymer medium and a dispersion medium.

(Polymer medium)
The polymer medium used in the present invention includes (A) a resin having a substituent having an ethylenically unsaturated bond and (B) a photopolymerization initiator, and irradiates energy rays such as ultraviolet rays, visible rays, and electron beams. Can be cured. The polymer medium is cured by irradiation with energy rays to form a resin matrix.

  (A) As resin which has an ethylenically unsaturated bond, silicone type resin, acrylic resin, polyester resin, etc. are preferable from points, such as synthetic | combination ease, light control performance, and durability. These resins are substituted with alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, hexyl group, and cyclohexyl group, and phenyl group. It is preferable to have an aryl group such as a naphthyl group from the viewpoints of light control performance and durability.

  Specific examples of the silicone resin include resins described in JP-B-53-36515, JP-B-57-52371, JP-B-58-53656, JP-B-61-17863, and the like. be able to.

Examples of the silicone resin include polydimethylsiloxane having both ends silanol groups, polydiphenylsiloxane having both ends silanol groups, polydiphenylsiloxane-dimethylsiloxane copolymer having both ends silanol groups, and polymethylphenylsiloxane having both ends silanol groups. Silanol group-containing siloxane polymers at both terminals; trialkylalkoxysilanes such as trimethylethoxysilane; ethylenically unsaturated bond-containing silane compounds such as (3-acryloxypropyl) methyldimethoxysilane; and organic tin such as 2-ethylhexanetin It is synthesized by dehydrogenative condensation reaction and dealcoholization reaction in the presence of a system catalyst. As the silicone resin, a solventless type is preferably used. That is, when a solvent is used for the synthesis of the silicone resin, it is preferable to remove the solvent after the synthesis reaction.

  When the polymer medium is a silicone resin having a polysiloxane structure having a (meth) acryloyl group, the number of repeating units having the (meth) acryloyl group is 1.3 to 5.0% by mass of the total number of repeating units. It is preferable that it is 1.5-4.5 mass%. When the number of repeating units having a (meth) acryloyl group is 1.3% by mass or more, the light control film containing the cured resin matrix is excellent in heat resistance and is 5.0% by mass or less. In addition, the light control film containing the cured resin matrix is excellent in heat resistance.

  Monomers for forming a polysiloxane structure having a (meth) acryloyl group include (3-acryloxypropyl) methyldimethoxysilane, (3-methacryloxypropyl) methyldimethoxysilane, and (3-acryloxypropyl) methyl. Diethoxysilane, (3-methacryloxypropyl) methyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxy Examples include silane.

  The acrylic resin includes, for example, (meth) acrylic acid alkyl ester, (meth) acrylic acid aryl ester, (meth) acrylic acid benzyl, main chain forming monomers such as styrene, (meth) acrylic acid, (meth) acrylic First, a prepolymer is synthesized by copolymerizing ethylenically unsaturated bond-introducing functional group-containing monomers such as hydroxyethyl acid, isocyanatoethyl (meth) acrylate, and glycidyl (meth) acrylate. By reacting monomers such as glycidyl (meth) acrylate, isocyanatoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid, etc. to the prepolymer to react with the functional group of the polymer Can be obtained.

  Moreover, there is no restriction | limiting in particular in the said polyester resin, What can be easily manufactured by a well-known method is mentioned.

  (A) The polystyrene-converted weight average molecular weight obtained by gel permeation chromatography of a resin having an ethylenically unsaturated bond is preferably 35,000 to 60,000, and 37,000 to 58,000. Is more preferable, and it is more preferable that it is 40,000-55,000. When the weight average molecular weight is 35,000 or more, the heat control property of the light control film containing the cured resin matrix is excellent, and when it is 60,000 or less, the fluidity of the resin matrix before curing is excellent. .

  The number of repeating units containing an ethylenically unsaturated bond of the resin having an ethylenically unsaturated bond is preferably 1.3 to 5.0% by mass of the total number of repeating units, and 1.5 to 4.5% by mass. % Is more preferable. When the number of repeating units containing an ethylenically unsaturated bond is in the above range, the heat resistance of the light control film containing the cured resin matrix is excellent.

  (A) The content of ethylenically unsaturated bonds in a resin having an ethylenically unsaturated bond is determined from the integral intensity ratio of hydrogen in NMR. Further, when the conversion rate of the charged raw material to the resin is known, it can also be obtained by calculation.

  As the (B) photopolymerization initiator used in the polymer medium, any photopolymerization initiator may be used as long as it can be decomposed by light irradiation to generate radicals and initiate polymerization of the polymerizable compound. (B) Examples of the photopolymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3 -Methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2- Hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, -Isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- ( 2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like, but are not limited thereto.

  Commercially available photopolymerization initiators include IRGACURE 651, IRGACURE 184, IRGACURE 500, IRGACURE 2959, IRGACURE 127, IRGACURE 754, IRGACURE 907, IRGACURE 369, IRGACURE 379, IRGACURE 379EG, IRGACURE 1300, IRGACURE 819D, IRGACURE 819D, IRGACURE 819D 1800, Irgacure 1870, Irgacure 784, Irgacure OXE01, Irgacure OXE02, Irgacure 250, Irgacure PAG103, Irgacure PAG108, Irgacure PAG121, Irgacure PAG203, Darocur 1173, Darocure MBF, Darocure T65, FDA The Manufactured by Bread Co., Ltd.), C0014, B1225, D1640, D2375, D2963, M1245, B0103, C1105, C0292, E0063, P0211, I0678, P1410, P1377, M1209, F0362, B0139, B1275, B0481, D1621, B1267, B1164 , C0136, C1485, I0591, F0021, A0061, B0050, B0221, B0079, B0222, B1019, B1015, B0942, B0869, B0083, B2380, B2381, D1801, D3358, D2248, D2238, D2253, B1231, M0792, 04 T0157, T2041, T2042, T1188, T1608 (above, Tokyo Chemical Industry Co., Ltd.) ), And the like.

  (B) It is preferable that it is 0.1-20 mass parts with respect to 100 mass parts of said (A) resin, and, as for the usage-amount of a photoinitiator, it is more preferable that it is 0.2-10 mass parts.

  In addition to the above-mentioned (A) resin having a substituent having an ethylenically unsaturated bond, the weight average molecular weight in terms of polystyrene measured by an organic solvent-soluble resin or thermoplastic resin, for example, gel permeation chromatography is 1,000 to 100,000 polyacrylic acid, polymethacrylic acid, and the like can also be used together as a constituent material of the polymer medium.

  Moreover, you may add additives, such as coloring inhibitors, such as dibutyltin dilaurate, in a polymer medium as needed. Furthermore, the polymer medium may contain a solvent, and as the solvent, tetrahydrofuran, toluene, heptane, cyclohexane, ethyl acetate, ethanol, methanol, isoamyl acetate, hexyl acetate, or the like can be used.

(Light control suspension)
The light adjusting suspension according to the present invention is obtained by dispersing light adjusting particles 10 in a dispersion medium 9 so as to be flowable.

-Dispersion medium-
As the dispersion medium in the light-adjusting suspension, one that is phase-separated from the polymer medium and a resin matrix that is a cured product thereof is used. Preferably, the light adjusting particles serve to disperse the light adjusting particles in a flowable state, and are selectively attached and coated on the light adjusting particles so that the light adjusting particles are phase-separated during phase separation from the polymer medium. A dispersion medium that acts to move to the droplet phase is preferred. Further, a dispersion medium that is not electrically conductive, has no affinity with a polymer medium, and has a refractive index approximate to that of a resin matrix formed from the polymer medium when a light control film is formed is preferable. A liquid copolymer is used as a dispersion medium having such properties.

  As the dispersion medium, for example, a (meth) acrylic acid ester oligomer having a fluoro group and / or a hydroxyl group is preferable, and a (meth) acrylic acid ester oligomer having a fluoro group and a hydroxyl group is more preferable. When such a copolymer is used, one monomer unit of either a fluoro group or a hydroxyl group has an affinity for the light control particle, and the remaining monomer unit is a droplet of the light control suspension in a polymer medium. Since it works to maintain it stably, the light adjusting particles are easily dispersed in the light adjusting suspension, and the light adjusting particles are easily induced in the phase-separated liquid droplet during the phase separation.

  Examples of the (meth) acrylic acid ester oligomer having such a fluoro group and / or hydroxyl group include 2,2,2-trifluoroethyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, acrylic acid 3 , 5,5-trimethylhexyl / 2-hydroxypropyl acrylate / fumaric acid copolymer, butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl acrylate / acrylic Butyl acrylate / acrylic acid 2-hydroxyethyl copolymer, acrylic acid 1H, 1H, 5H-octafluoropentyl / butyl acrylate / acrylic acid 2-hydroxyethyl copolymer, acrylic acid 1H, 1H, 2H, 2H-hepta Decafluorodecyl / butyl acrylate / 2-hydroxy acrylate Chill copolymer, 2,2,2-trifluoroethyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl methacrylate / butyl acrylate / acrylic Acid 2-hydroxyethyl copolymer, methacrylic acid 1H, 1H, 5H-octafluoropentyl / butyl acrylate / acrylic acid 2-hydroxyethyl copolymer, methacrylic acid 1H, 1H, 2H, 2H-heptadecafluorodecyl / Butyl acrylate / acrylic acid 2-hydroxyethyl copolymer, butyl methacrylate / methacrylic acid 2-hydroxyethyl copolymer, hexyl methacrylate / methacrylic acid 2-hydroxyethyl copolymer, octyl methacrylate / 2-methacrylic acid 2- Hydroxyethyl copolymer, decyl methacrylate / 2-hydroxyethyl methacrylate copolymer, undecyl methacrylate / 2-hydroxyethyl methacrylate copolymer, dodecyl methacrylate / 2-hydroxyethyl methacrylate copolymer, tridecyl methacrylate / 2-hydroxyethyl methacrylate copolymer Examples thereof include a polymer, a tetradecyl methacrylate / 2-hydroxyethyl methacrylate copolymer, a hexadecyl methacrylate / 2-hydroxyethyl methacrylate copolymer, and an octadecyl methacrylate / 2-hydroxyethyl methacrylate copolymer.

  These (meth) acrylic acid ester oligomers preferably have a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of 1,000 to 20,000, preferably 2,000 to 10,000. It is more preferable.

  It is preferable that the usage-amount of the fluoro group containing monomer used as the raw material of these (meth) acrylic acid ester oligomers is 6-12 mass% of the monomer total amount which is a raw material, More effectively, it is 7-8 mass%. is there. When the usage-amount of a fluoro group containing monomer is 12 mass% or less, the raise of a refractive index is suppressed and there exists a tendency for it to be excellent in the light transmittance.

Moreover, it is preferable that the usage-amount of the hydroxyl-containing monomer used as the raw material of these (meth) acrylic acid ester oligomers is 0.5-22.0 mass%, and is 1-8 mass% more effectively. . When the usage-amount of a hydroxyl-containing monomer is 22.0 mass% or less, the raise of a refractive index is suppressed and there exists a tendency for it to be excellent in the light transmittance.
The refractive index of the dispersion medium is preferably close to the refractive index of the resin matrix formed from the polymer medium, specifically, preferably 1.467 to 1.477, and 1.469. More preferably, it is -1.475, and it is still more preferable that it is 1.470-1.474.

-Light control particles-
Examples of the light adjusting particles include pyrazine-2,3-dicarboxylic acid dihydrate, pyrazine-2,5-dicarboxylic acid dihydrate, pyridine-2,5- A polyiodide needle-like crystal prepared by reacting one substance selected from the group consisting of dicarboxylic acid and monohydrate with iodine and iodide is preferably used. The light control particles have no affinity for the polymer medium or the resin component in the polymer medium (that is, the resin (A) having a substituent having an ethylenically unsaturated bond) and the dispersibility of the light control particles. Is prepared in the presence of a polymeric dispersant capable of increasing the viscosity. Examples of the polymer dispersant that can be used include nitrocellulose. Examples of iodide include calcium iodide.

Examples of the polyiodide thus obtained include, for example, the following general formula CaI ₂ (C ₆ H ₄ N ₂ O ₄ ) · XH ₂ O (X: 1 to 2).
CaI _a (C ₆ H ₄ N ₂ O ₄ ) _b · cH ₂ O (a: 3 to 7, b: 1 to 2, c: 1 to 3)
The thing represented by is mentioned. These polyiodides are preferably acicular crystals.

  US Pat. No. 2,041,138 (E.H.Land) and US Pat. No. 2,306,108 (Land et al.) Are used as light control particles for light control suspensions for light control films. ), U.S. Pat. No. 2,375,963 (Thomas), U.S. Pat. No. 4,270,841 (RL Sax) and British Patent 433,455. Light conditioning particles can also be used. The polyiodide crystals known by these patents are obtained by selecting one of pyrazinecarboxylic acid or pyridinecarboxylic acid and reacting with iodine, chlorine or bromine to produce polyiodide, polychloride or polybromide. And so on. These polyhalides are complex compounds in which a halogen atom reacts with an inorganic substance or an organic substance, and their detailed production methods are disclosed, for example, in US Pat. No. 4,422,963 to Sax.

  As disclosed by Sachs, in the process of synthesizing the light control particles, the light control particles of uniform size are formed, and the dispersibility of the light control particles in a specific suspension medium is improved. Therefore, as described above, it is preferable to use a polymer material such as nitrocellulose as the polymer dispersant. However, when nitrocellulose is used, crystals coated with nitrocellulose are obtained, and when such crystals are used as light control particles, the light control particles do not float in the droplets separated during phase separation, May remain in the resin matrix.

  In order to prevent this, it is preferable to use a silicone-based resin as the resin having a substituent having an ethylenically unsaturated bond (A) in the polymer medium. In this case, the light adjusting particles are easily dispersed and suspended in the fine droplets formed by the phase separation, and as a result, a more excellent variable ability can be obtained.

  The particle size of the light control particles is preferably the following size from the relationship between the response time with respect to the applied voltage when the light control film is used and the aggregation and precipitation in the light control suspension.

  The average major axis of the light control particles is preferably 225 to 625 nm, more preferably 250 to 550 nm, and further preferably 300 to 500 nm.

  The ratio of the major axis to the minor axis of the light control particles, that is, the average aspect ratio is preferably 3-8, more preferably 3.3-7, and still more preferably 3.6-6.

  The major axis and minor axis of the light adjusting particles in the present invention are obtained by photographing the light adjusting particles with an electron microscope such as a scanning electron microscope or a transmission electron microscope, and arbitrarily extracting 50 light adjusting particles from the photographed image, The major axis and minor axis of each light control particle can be calculated as an average value. Here, the major axis is the length of the longest part of the light control particles projected in the two-dimensional visual field by the photographed image. The minor axis is the length of the longest part orthogonal to the major axis.

  In addition, as a method for evaluating the particle diameter of the light control particles in the present invention, a particle size distribution meter using the principle of a photon correlation method or a dynamic light scattering method can be used. In this method, the size and shape of the particles are not directly measured, but the equivalent diameter is evaluated on the assumption that the particles are spherical, which is different from the SEM observation. In particular, when using the Zetasizer Nano series manufactured by Sysmex Corporation and assuming that the equivalent diameter output as Z average is the particle diameter, the average particle diameter of the light control particles (hereinafter referred to as “average particle diameter determined by particle size distribution measurement”) 135-220 nm is preferable, 140-210 nm is more preferable, and 145-205 nm is still more preferable.

  This Z average value is a measured value of a different particle size distribution meter based on, for example, the optical correlation method or the dynamic light scattering method, specifically, the long diameter of the light adjusting particle measured by an electron microscope such as the transmission electron microscope described above. It is known to show a good correlation with the short diameter, and is suitable as an index for evaluating the particle diameter.

  It is preferable to contain 1-15 mass% of light adjustment particles in this invention with respect to the total mass of light adjustment suspension, and it is more preferable to contain 2-10 mass%. When the content is 1% by mass or more, the light shielding effect when using the light control film is increased, which is preferable. Moreover, in the case of 15 mass% or less, inhibition of hardening of the siloxane resin by an energy ray can be suppressed at the time of light control film manufacture.

  Moreover, it is preferable to contain the dispersion medium in this invention 30-99 mass% with respect to the total mass of light adjustment suspension, and it is more preferable to contain 50-96 mass%. In the case of 30% by mass or more, the light shielding effect is increased, and in the case of 99% by mass or less, inhibition of curing of the siloxane resin is suppressed.

  Moreover, it is preferable that a light control material contains 1-100 mass parts of light adjustment suspensions with respect to 100 mass parts of polymer media, It is more preferable to contain 4-70 mass parts, 6-60 More preferably, it is contained in an amount of 8 to 50 parts by mass. When the content of the light control suspension is 1% by mass or more, the light shielding effect is excellent, and when the content is 100% by mass or less, inhibition of curing of the siloxane resin is suppressed.

  In the present invention, the refractive index of the polymer medium and the refractive index of the dispersion medium are preferably approximated. Specifically, the difference in refractive index between the polymer medium and the dispersion medium in the present invention is preferably 0.005 or less, more preferably 0.003 or less. When the difference between the refractive index of the polymer medium and the refractive index of the dispersion medium is 0.005 or less, the turbidity of the light control film is low, and the light control film is excellent in transparency.

<Measurement method of curing rate>
The present invention relates to a light control layer comprising a resin matrix which is a cured product of a polymer medium and a light control suspension dispersed in the resin matrix, and includes two transparent conductive resin base materials (hereinafter referred to as “base materials”). It is related with the method of measuring the hardening rate of the said resin matrix in the light control film formed by pinching | interposing in.

  In the present invention, the curing rate of the resin matrix is measured by transmitting near infrared light through the light control film and measuring the infrared spectrum thereof. The light control film used for the measurement may be a sample prepared separately for this measurement, or the product light control film may be used directly. Hereinafter, the sample used for measuring the near-infrared spectrum is referred to as “measurement sample”.

The curing rate is measured by confirming the increase or decrease in the absorption peak of the first overtone of the stretching vibration of the carbon-hydrogen bond that binds to the carbon-carbon double bond that appears in the vicinity of 6170 cm ^{−1 in the} near-infrared spectrum. If interference fringes appear when the near infrared light is transmitted through the measurement sample, it is difficult to confirm the absorption peak near 6170 cm ^−1, and it is difficult to accurately calculate the curing rate.

  Therefore, in the present invention, when interference fringes are generated during the measurement of the near-infrared spectrum, a light control film provided with two transparent conductive resin substrates that satisfy the following formula (I) is used. Infrared spectrum is measured.

Formula (I): Maximum height of surface roughness (Ry) in the irradiation region of the near infrared light ≧ wavelength λ × 1/2 of the interference fringes

Hereinafter, the transparent conductive resin base material in which the maximum height (Ry) of the surface roughness in the irradiation region of near infrared light is not less than the wavelength λ × 1/2 of the interference fringes is referred to as “base material Ry”.
A measurement sample for measuring the wavelength of interference fringes is referred to as a “first measurement sample”, and a measurement sample including two base materials Ry is referred to as a “second measurement sample”.

  By using the second measurement sample including the two base materials Ry, generation of interference fringes that hinder the measurement of the curing rate can be suppressed. The reason is considered as follows.

  When near-infrared light is incident from one substrate of the measurement sample, light that is transmitted as it is from the other substrate, light that is transmitted after being reciprocated once on the substrate surface, light that is transmitted after being repeatedly reflected several times, etc. The transmitted light includes a plurality of waves having different phases. When the phase difference between the plurality of waves is 0, the most frequent interference occurs and the interference fringes are remarkably generated. On the other hand, when the phase difference is 180 °, they cancel each other, and the generation of interference fringes is suppressed. In other words, in order to suppress the occurrence of interference fringes, the optical path length may be shifted so that the waveforms of a plurality of waves overlap in a mountain and a valley. In the present invention, the optical path length is adjusted by the difference in thickness of the substrate at the measurement site of the measurement sample, that is, the surface roughness of the substrate. In particular, in the present invention, the substrate surface is adjusted using the maximum height Ry among the indicators of the surface roughness of the substrate.

  When the thickness difference of the substrate is (x + 0.5) times (x is an integer of 0 or 1 or more), such as 0.5 times, 1.5 times, and 2.5 times the wavelength λ of the interference fringes The phases of the plurality of waves cancel each other, and the generation of interference fringes is suppressed. On the other hand, when the difference in thickness of the substrate is x times (x is an integer of 1 or more), such as 1 time, 2 times, or 3 times the wavelength λ of the interference fringes, the interference is rather increased. Streaks are noticeably generated.

  Therefore, if the thickness difference of the substrate can be accurately controlled, adjusting the thickness difference of the substrate to be (x + 0.5) times the wavelength λ of the interference fringes is effective in suppressing the interference fringes. is there. However, the substrate surface usually has irregularities, and such a method is not practical.

  Here, the maximum height Ry of the surface roughness will be described. As shown in FIG. 5, the maximum height Ry indicates the maximum value of the height difference in the roughness curve. Therefore, the thickness difference of the substrate having the maximum surface roughness height Ry of A μm is A μm at the maximum, and a thickness difference smaller than A μm exists in the substrate in a composite manner. Therefore, if the maximum height Ry of the surface roughness of the substrate is ½ or more of the wavelength λ of the interference fringes, it is considered that the phase of transmitted light is combined and the occurrence of interference fringes can be suppressed. More preferably, the maximum height Ry of the surface roughness of the substrate is 1 or more times the wavelength λ of the interference fringes, more preferably 2 or more, still more preferably 5 or more, and more preferably 8 or more. More preferably.

  Specifically, the transparent conductive resin substrate is a PET film, the thickness is about 50 μm to 200 μm, the thickness of the light control layer is about 50 μm to 150 μm, and the refractive index at the time of scattering of the light control layer is 1.465. In the case of a light control film of about 1.480, the maximum height Ry of the surface roughness of the PET film in the near infrared light irradiation region is preferably adjusted to 0.2 μm to 4.0 μm. More preferably, the thickness is adjusted to 0.5 μm to 3.7 μm, and more preferably 1.0 μm to 3.5 μm.

From the above, according to the method for measuring the curing rate of the light control film of the present invention, the curing rate of the resin matrix in the light control layer of the light control film can be reliably maintained without peeling off the base material. Can be measured. Therefore, the measuring method of the curing rate of the present invention can be used as an index for reliability evaluation, and the measuring method is excellent in quickness and simplicity.
Hereinafter, the measuring method of the hardening rate of the light control film of this invention is demonstrated in detail.

[Preparation of measurement sample]
First, a light control film comprising a light control layer comprising a resin matrix which is a cured product of a polymer medium and a light control suspension dispersed in the resin matrix, sandwiched between two transparent conductive resin substrates. A certain first measurement sample is prepared. Details of the method for producing the light control film will be described later. The substrate may be provided with the above-described primer.

  The first measurement sample is irradiated with near infrared light for measuring a near infrared spectrum. At that time, it is confirmed whether an interference fringe is observed using an instantaneous spectrophotometer F-20 (manufactured by Filmetrics Co., Ltd.) or the like. If no interference fringes are confirmed in the first measurement sample, the near-infrared spectrum is subsequently measured. Note that interference fringes may not be observed depending on the thickness and refractive index of the base material, the thickness and refractive index of the light control layer, and combinations thereof.

  When interference fringes are observed in the first measurement sample, the wavelength of the interference fringes is measured. Then, from the wavelength λ of the obtained interference fringes, the second dimming layer is sandwiched between two base materials Ry having a maximum surface roughness of λ / 2 or more at a near infrared light irradiation site. A measurement sample is prepared.

  The method for producing the second measurement sample is not particularly limited as long as the surface roughness of the region irradiated with near infrared light can satisfy the above formula (I). For example, there is a method of dissolving both base materials in the first measurement sample with a solvent that can be dissolved. Specifically, for example, a method of rubbing the measurement region of two substrates with a cotton swab or cloth soaked with the solvent can be used.

  As another method, for example, when the wavelength of interference fringes is measured from the first measurement sample and λ / 2 is calculated, a base material Ry having a maximum height Ry of λ / 2 or more is separately procured. The method of producing the 2nd measurement sample provided with the light control layer pinched | interposed by the said base material Ry of sheet | seat is mentioned. Procurement of the base material Ry may be obtained by previously dissolving the base material Ry with a solvent or the like before sandwiching the light control layer, or by purchasing and obtaining a base material Ry having the maximum height Ry. Good.

  In view of the reduction of the amount of measurement sample discarded and the complexity of procurement of the base material Ry, a method of adjusting the surface of the base material of the measurement sample so as to satisfy the above formula (I) by dissolving with a solvent is desirable.

  As the solvent, when the two substrates are composed of polyethylene terephthalate (PET), for example, trifluoroacetic acid, trifluoroacetic acid / dichloroethane mixed solvent, 1,1,2,2-tetrachloroethane / phenol A mixed solvent, dimethyl terephthalate or hexafluoroisopropanol can be mentioned, and hexafluoroisopropanol is preferable in view of availability and solubility of the base material.

  In general, the light control film is produced as a continuous film by the roll-to-roll method, so the second measurement sample whose surface is dissolved with a solvent is a product. It may be a part of the light control film. When a part of the product is used as the second measurement sample for measuring the curing rate, the curing rate of the product can be surely grasped, which is extremely excellent as an index for reliability evaluation.

[Spectroscopic measurement by near-infrared light irradiation]
Near-infrared light is incident on the prepared measurement sample and a spectrum is measured. The measurement of the curing rate is preferably performed from the increase or decrease of the absorption peak of the first overtone of the stretching vibration of the carbon-hydrogen bond bonded to the carbon-carbon double bond appearing in the vicinity of 6170 cm ⁻¹ . For example, FT / IR-6000 (manufactured by JASCO Corporation, InGaAs detector, resolution 4 cm ⁻¹ ) or the like can be used for the measurement of the near-infrared spectrum.

In the near-infrared spectrum, since the peak observed in the vicinity of 6050 cm ⁻¹ is a peak derived from a component that does not change before and after curing, the C═C bond observed in the vicinity of 6170 cm ⁻¹ using this peak as an internal standard. The curing rate is calculated from the ratio of the absorption peak area of the first overtone derived from the internal standard peak area.

The first overtone absorption peak area derived from uncured C = C bond is (A ₀ ), the area after curing is (A _x ), the internal standard peak area when uncured is (B ₀ ), the area after curing Is (B _x ), A _x = 0 when completely cured, so the curing rate (%) is calculated from the following equation.

Curing rate (%) = [1- (A _x / B _x ) / (A ₀ / B ₀ )] × 100

  In the measurement of the near-infrared spectrum, the incident angle of near-infrared light is preferably 20 to 70 °, more preferably 30 to 60 ° with respect to the surface of the measurement sample. When the incident angle of near infrared light is 30 ° or more and 60 ° or less, interference fringes are further suppressed, which is preferable.

<Manufacturing method of light control film>
By using the method for measuring the curing rate of the present invention, a method for producing a light control film excellent in production management can be provided. Furthermore, the light control film excellent in heat resistance can be provided by using the measuring method of this hardening rate.

  In order to obtain a light control film, first, a liquid light adjusting suspension is homogeneously mixed with a polymer medium, and the light adjusting suspension is composed of a mixed liquid dispersed in the polymer medium in the form of droplets. A dimming material is prepared.

Specifically, the light control material is prepared as follows. A liquid in which the light control particles are dispersed in a solvent and a dispersion medium of the light control suspension are mixed, and the solvent is distilled off with a rotary evaporator or the like to prepare a light control suspension.
Next, the light control suspension and the polymer medium are mixed to obtain a mixed liquid (light control material) in which the light control suspension is dispersed in a droplet state in the polymer medium. The light-modulating material usually contains 1 to 100 parts by mass, preferably 6 to 70 parts by mass, and more preferably 6 to 60 parts by mass of the light adjusting suspension with respect to 100 parts by mass of the polymer medium.

  This light control material is apply | coated by fixed thickness on the transparent conductive layer of the said transparent conductive resin base material, and a light control layer is formed. For application of the light-modulating material, for example, known coating means such as a bar coater, applicator, doctor blade, roll coater, die coater, and comma coater can be used. When the light-modulating material is applied to the surface of the primer layer provided on the substrate, or when a substrate having no primer layer is used on one side, it can be directly applied to the substrate. In addition, when apply | coating, you may dilute with a suitable solvent as needed. When a solvent is used, drying is required after coating on the transparent conductive resin substrate.

  Tetrahydrofuran, toluene, heptane, cyclohexane, ethyl acetate, ethanol, methanol, isoamyl acetate, hexyl acetate, etc. can be used as a solvent used for application of the light modulating material. In order to form a film in which the liquid light control suspension is dispersed in the form of fine droplets in a solid resin matrix, the light control material is mixed with a homogenizer, an ultrasonic homogenizer, or the like, and then a polymer medium. A method of finely dispersing the light control suspension therein, a phase separation method by polymerization of a resin component in a polymer medium, a phase separation method by solvent volatilization, a phase separation method by temperature, or the like can be used.

  After applying the light-modulating material or, if necessary, drying and removing the solvent contained in the light-modulating material, the polymer medium is cured by irradiating ultraviolet rays using a high-pressure mercury lamp or the like. As a result, a light control layer in which the light control suspension is dispersed in the form of droplets is formed in a resin matrix made of a cured polymer medium. The light transmittance of the light control layer can be adjusted by variously changing the mixing ratio of the polymer medium and the light control suspension.

  The size (average droplet diameter) of the light control suspension dispersed in the resin matrix is usually 0.5 to 100 μm, preferably 0.5 to 20 μm, more preferably 1 to 5 μm. is there. The size of the droplets depends on the concentration of each component constituting the light control suspension, the viscosity of the light control suspension and the polymer medium, and the compatibility of the dispersion medium in the light control suspension with the polymer medium. It is decided by etc.

  The average droplet diameter is calculated, for example, by taking an image such as a photograph from one surface direction of the light control film using SEM, measuring a plurality of arbitrarily selected droplet diameters, and calculating the average value thereof. Can do. It is also possible to capture a visual field image of the light control film with an optical microscope into a computer as digital data and calculate it using image processing integration software.

  A light control film is obtained by sticking the other transparent conductive resin base material on the light control layer formed in this way.

  Alternatively, the light-modulating material is applied on a substrate with a constant thickness, and if necessary, the solvent in the light-modulating material is dried and removed, and then laminated on the other substrate, and then irradiated with ultraviolet rays. The polymer medium may be cured.

  Furthermore, a light control layer may be formed on both transparent conductive layers of the two transparent conductive resin substrates, and the light control layers may be laminated so as to be in close contact with each other.

  The thickness of the light control layer is preferably 5 to 1,000 μm, and more preferably 20 to 100 μm.

  In the manufacturing method of the light control film of this invention, after measuring the hardening rate of the resin matrix in the light control film produced by said method, or in the measurement sample produced separately by the same method as the above, this hardening rate is calculated | required. Based on this, a curing condition with a predetermined curing rate is obtained, and a light control film cured under the curing condition is produced. By performing the feedback of the curing conditions in this way, the variation in the curing rate between the product rods can be extremely reduced.

  The measurement of the curing rate of the resin matrix is performed by irradiating the second measurement sample in which the light control layer is sandwiched between two substrates whose surface roughness satisfies the above formula (I) with near infrared light. . The method for producing the second measurement sample is as described above. The method for measuring the curing rate of the resin matrix in the second measurement sample is as described above.

  The curing rate obtained by measuring the curing rate is applied to the previously determined relationship between the curing condition of the polymer medium and the curing rate, and the curing condition of the polymer medium that gives a predetermined curing rate is determined. derive.

  The predetermined curing rate is preferably 75 to 100%, more preferably 85 to 100%, and still more preferably 90 to 100% from the viewpoints of heat resistance and light resistance. In particular, in the polymer medium that forms a resin matrix by curing, the curing is performed when the number of repeating units having an ethylenically unsaturated bond used for curing is 1.3 to 5.0% by mass of the total number of repeating units. The rate is preferably 75 to 100%. By adjusting the proportion of the number of repeating units having an ethylenically unsaturated bond and the curing rate within the above range, a light control film having excellent heat resistance can be obtained. The reason is not clear, but when the curing rate is 75% or less, it is presumed that the viscosity of the uncured portion of the light control film is reduced by heating, and bonding of droplets is caused.

  Examples of the curing conditions of the polymer medium related to the curing rate include the irradiation amount of ultraviolet rays for curing, the type of gas in the curing atmosphere, the flow rate, and the curing temperature. The relationship between the factors related to the curing rate and the curing rate is calibrated in advance. Among these, since it is the ultraviolet irradiation amount that is directly related to the curing rate, it is preferable that at least the relationship between the ultraviolet irradiation amount and the curing rate is calibrated in advance.

  Thus, the said hardening rate obtained by the measurement of the near-infrared spectroscopy spectrum is applied to the relationship between the hardening conditions and hardening rate of the polymer medium which weighed beforehand. Then, the curing conditions that fall within a predetermined curing rate (for example, 75 to 100%) are calibrated and derived. Specifically, for example, when the curing rate obtained by measurement of the near-infrared spectrum is 50% and is outside the target curing rate range of 75 to 100%, the curing rate is set to 75 to 100%. The curing conditions (for example, the irradiation amount of ultraviolet rays) for obtaining are determined from a calibration curve prepared in advance.

  Then, a light control film containing a resin matrix obtained by curing the polymer medium is produced under the derived curing conditions. About this light control film, the same cure rate as the above is measured and it is confirmed whether it is in the range of the target cure rate. If it is outside the target curing rate, find the curing condition within the range of the target curing rate again from the relationship between the curing condition and the curing rate weighed in advance, and cured under that curing condition A light control film is produced.

  Thereafter, the process of measuring the curing rate of the light control film by the near-infrared spectrum, the process of deriving the curing conditions, and the process of producing the light control film under the derived curing conditions are repeated until it falls within the target curing rate range. . Alternatively, the measurement of the curing rate of the resin matrix may be performed only once, and a curing condition for obtaining a desired curing rate may be derived based on the curing rate, and a product may be manufactured under the curing condition.

In FIG. 6, the procedure of an example of preparation of the light control film of this invention is shown with a flowchart.
In FIG. 6, in step 11, a second measurement sample for measuring the curing rate by the near-infrared spectrum is prepared by the above method. In the second measurement sample, the surface roughness (maximum height Ry) of both base materials in the irradiation region of near-infrared spectroscopy satisfies the above formula (I). The maximum height Ry of the surface roughness is obtained from the first measurement sample in which interference fringes are observed. When no interference fringes are observed in the first measurement sample, the near-infrared spectrum is measured using the first measurement sample.

  The curing of the light control layer in the first and second measurement samples and the light control film as a product may be cured before being sandwiched between the substrates, or after the uncured light control layer is sandwiched between the substrates. The light control layer may be cured. However, in order to ensure the accuracy of the curing rate of the light control film as a product, the curing time of the first and second measurement samples is matched with the curing time of the light control film as a product.

  In step 13, based on the above method, the curing rate of the resin matrix in the second measurement sample is measured by a near infrared spectrum.

  In step 15, it is determined whether the curing rate obtained by measuring the near-infrared spectrum is within the target curing rate range. If it is within the target curing rate range, this operation is terminated. If it is outside the range of the target curing rate, the process proceeds to step 17.

  In step 17, a curing condition that falls within the range of the target curing rate is obtained again from the relationship between the curing condition and the curing rate that have been calibrated in advance. Then, returning to step 11, a second measurement sample cured by changing to the obtained curing conditions is prepared.

  Steps 11 to 17 are repeated until the curing rate obtained by measuring the near-infrared spectrum is within the target curing rate range. This operation is terminated when the target curing rate is within the range.

  In the flowchart of FIG. 6, it has been described that Step 11 to Step 17 are repeated until the target curing rate is within the range, but the curing rate is measured only once, and thereafter the curing rate obtained from the curing rate is obtained. You may manufacture a light control film on condition.

  According to the method for producing a light control film of the present invention, a constant level of cure rate is obtained based on the cure rate measured with the substrate remaining attached, without requiring a complicated operation such as peeling the substrate. The light control film which has can be produced. Moreover, since the value of the curing rate can be obtained as a constant value without individually considering factors such as the irradiation amount of ultraviolet rays and the curing atmosphere, the production method of the light control film of the present invention has an effect that production management is easy. Play. Furthermore, the curing rate used in the production method of the present invention is calculated from the absorption peak due to the carbon-carbon double bond, and thus is a value that directly represents the amount of the carbon-carbon double bond. is there. Therefore, since a light control film can be manufactured based on an exact cure rate, a light control film excellent in reliability can be manufactured.

<Light control by light control film>
The light control film obtained by the manufacturing method of the light control film of this invention can adjust light transmittance arbitrarily by formation of an electric field. Even when no electric field is formed, the light control film maintains a clear coloring state without light scattering, and is converted into a transparent state when the electric field is formed. This ability exhibits a reversible repeat characteristic of over 200,000 times.

  The power source used for operating the light control film is alternating current, and can be in the frequency range of 10 to 100 volts (effective value) and 30 Hz to 500 kHz. The light control film of this invention can make the response time with respect to an electric field within 1-50 seconds at the time of decoloring, and within 1-100 seconds at the time of coloring.

  In addition, as a result of an ultraviolet irradiation test using 750 W ultraviolet rays or the like, the ultraviolet durability shows a stable variable characteristic even after 250 hours have passed, and even when left at -50 ° C. to 90 ° C. for a long time, It is possible to maintain variable characteristics.

In the production of a light control film using liquid crystal, which is a conventional technique, when a method using an emulsion using water is used, the liquid crystal often reacts with moisture and loses its light adjustment characteristics. There is a problem that it is difficult.
However, in the present invention, not a liquid crystal but a liquid light adjusting suspension in which light adjusting particles are dispersed in the light adjusting suspension is used. Therefore, unlike a light control film using liquid crystal, an electric field is used. Even when no is applied, light is not scattered, and the coloration state is excellent and the viewing angle is not limited. The light variability can be arbitrarily adjusted by adjusting the content of the light adjusting particles, the droplet shape and the layer thickness, or adjusting the electric field strength.

  In addition, since the light control film of the present invention does not use liquid crystal, the response time difference due to a decrease in variable ability due to ultraviolet exposure and a voltage drop that occurs between the peripheral part and the central part of the transparent conductive resin base material unique to large products Is also resolved.

  As shown in FIG. 2, when no electric field is applied to the light control film according to the present invention, due to the Brownian motion of the light control particles in the light control suspension, the light absorption of the light control particles is due to the dichroic effect. It shows a clear coloring state. However, as shown in FIG. 3, when an electric field is applied, the light adjusting particles in the droplet or the droplet connected body are arranged in parallel to the electric field and converted into a transparent state.

  Moreover, since the light control film of this invention is a film state, the problem of the light control glass by the prior art which uses a liquid light adjustment suspension as it is is eliminated. That is, difficulty in injecting a liquid suspension between two transparent conductive resin substrates, expansion of the bottom due to the difference in water pressure between the upper and lower parts of the product, changes in the substrate spacing due to the external environment such as wind pressure The local hue change due to, and the leakage of the light control material due to the destruction of the sealing material between the transparent conductive resin base materials are solved.

  Further, in the case of a light control window according to the prior art using liquid crystal, the liquid crystal is easily deteriorated by ultraviolet rays, and the operating temperature range is narrow due to the thermal characteristics of nematic liquid crystal. Furthermore, also in terms of optical characteristics, when no electric field is applied, it shows a milky white translucent state due to light scattering, and even when an electric field is applied, it is not completely sharpened and the milky state is There are remaining issues. Therefore, in such a light control window, a display function based on light blocking and transmission, which is used as an operation principle in existing liquid crystal display elements, is impossible. However, such a problem can be solved by using the light control film according to the present invention.

  The light control film of the present invention includes, for example, indoor and outdoor partitions, window glass / skylights for buildings, various flat display elements used in the electronics industry and video equipment, various instrument panels, and existing liquid crystal display elements. Suitable for applications such as light shutters, various indoor / outdoor advertisements and signboards, window glass for aircraft / railway vehicles / ships, window glass / back mirror / sunroof for automobiles, glasses, sunglasses, sun visors, etc. Can be used.

  As an application method, it is possible to directly use the light control film of the present invention. However, depending on the application, for example, the light control film of the present invention may be sandwiched between two base materials or used. It may be used by pasting it on one side. As said base material, glass, the polymer film similar to the said transparent resin base material, etc. can be used, for example.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples.

(Production example of light control particles)
8.5% by mass iodine isopentyl acetate solution (hereinafter referred to as “iodine solution”) from iodine (special grade of JIS reagent, manufactured by Wako Pure Chemical Industries, Ltd.) and isopentyl acetate (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) ) Was prepared. Further, a 20.0 mass% cellulose nitrate isopentyl acetate solution (hereinafter referred to as “cellulose nitrate solution”) was prepared from nitrocellulose 1 / 4LIG (trade name: manufactured by Bergerac NC) and isopentyl acetate. Further, calcium iodide hydrate (chemical use, manufactured by Wako Pure Chemical Industries, Ltd.) was dried by heating and dehydrated, and then dissolved in isopentyl acetate to prepare a 20.9 mass% calcium iodide solution.

  A 300 ml four-necked flask was equipped with a stirrer and a condenser, 65.6 g of the iodine solution and 82.93 g of the cellulose nitrate solution were added, and the flask was heated at a water bath temperature of 35 to 40 ° C. After the temperature of the flask contents reached 35 to 40 ° C., 7.41 g of dehydrated methanol (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) and 0.71 of purified water (produced by Wako Pure Chemical Industries, Ltd.) were added. 525 g was added and stirred. Thereto was added 15.6 g of calcium iodide solution and then 3.70 g of pyrazine-2,5-dicarboxylic acid (manufactured by Nikka Techno Service Co., Ltd.). The water bath temperature was set at 42 to 44 ° C. and the mixture was stirred for 4 hours and then allowed to cool to obtain a synthetic solution containing light adjusting particles.

  The obtained light control particles have an average particle size of 185 nm determined by particle size distribution measurement (measured with a submicron particle analyzer (product name: N4MD, manufactured by Beckman Coulter)), an average major axis by SEM observation of 310 nm, and an average aspect. The ratio was 4.4. In addition, in the observation by SEM, the average value of the major axis and the aspect ratio was obtained from 100 light adjusting particles.

  In addition, after centrifuging the obtained synthetic liquid at 9260 G for 5 hours, the supernatant liquid is removed by decantation, isopentyl acetate 5 times the mass of the precipitate is added to the precipitate remaining at the bottom, and the precipitate is dispersed by ultrasound. The mass of the whole liquid was measured. The dispersed liquid was weighed on a 1 g metal plate, dried at 120 ° C. for 1 hour, then weighed again to determine the nonvolatile content ratio. From the nonvolatile content ratio and the mass of the entire liquid, the total nonvolatile content, that is, the precipitation yield of 4.15 g was determined.

(Production example of light control suspension)
45.5 g of the light control particles obtained in the above-mentioned “Production Example of Light Control Particles” was added to butyl acrylate (Wako Special Grade, Wako Pure Chemical Industries, Ltd.) / Methacrylic acid as a dispersion medium for the light control suspension. Copolymer (monomer molar ratio: 2,2,2-trifluoroethyl (for industrial use, manufactured by Kyoeisha Chemical Industry Co., Ltd.) / 2-hydroxyethyl acrylate (Wako Grade 1, manufactured by Wako Pure Chemical Industries, Ltd.) 18 / 1.5 / 0.5, weight average molecular weight: 3,800, refractive index 1.4719) In addition to 50 g, the mixture was mixed with a stirrer for 30 minutes. Subsequently, isoamyl acetate was removed under reduced pressure at 80 ° C. for 3 hours under a vacuum of 133 Pa using a rotary evaporator to produce a stable liquid light-conditioning suspension free of sedimentation and aggregation of light-conditioning particles.

(Production example of energy ray curable polysiloxane resin)
In a four-necked flask equipped with a Dean-Stark trap, a condenser, a stirrer, and a heating device, 15.0 g of (3-acryloxypropyl) methyldimethoxysilane (trade name: KBM-5102, manufactured by Shin-Etsu Chemical Co., Ltd.) , 1.9 g of distilled water, 0.04 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 8.9 g of a mixed solvent of ethanol / methanol = 9/1 by mass ratio, heated to 65 ° C. for 5 hours Reacted. After cooling the reaction solution to 40 ° C. or lower, the pressure was reduced to 100 Pa, the temperature was raised to 70 ° C., and a desolubilization step was performed for 2 hours. Then, it cooled to room temperature and obtained 14.0g of compounds which converted a part of alkoxysilane into silanol. The conversion rate to silanol was 54.5%.

The conversion rate of alkoxysilane to silanol is determined based on the intensity (A) of a peak derived from a hydroxyl group (near 3435 cm ⁻¹ ) and the intensity (B) of a peak derived from an alkoxy group (near 2835 cm ⁻¹ ) in infrared spectroscopy. = A / (A + B) × 100. From the infrared spectroscopic measurement after conversion of dimethoxysilane to silanol, (A) was Abs = 0.250, and (B) was Abs = 0.221, so the conversion rate was calculated to be 54.5%.

  In a four-necked flask equipped with a Dean-Stark trap, condenser, stirrer, and heating device, both ends silanol polydimethylsiloxane (trade name: X-21-3114, manufactured by Shin-Etsu Chemical Co., Ltd.) 48.0 g, both 170.0 g of terminal silanol polydimethyldiphenylsiloxane (trade name: X-21-3193B, manufactured by Shin-Etsu Chemical Co., Ltd.), 9.0 g obtained by converting the methoxy group of the KBM-5102 into silanol, bis (2-ethyl Hexanoic acid) tin (trade name: KCS-405T, manufactured by Johoku Chemical Industry Co., Ltd.) (0.01 g) was charged, and the reaction was performed by refluxing in heptane at 100 ° C. for 5 hours. The temperature was cooled to 50 ° C., 109.0 g of trimethylethoxysilane (trade name: KBM-31, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was refluxed at 85 ° C. for 2 hours to cause an end cap reaction.

  Next, the temperature was cooled to 75 ° C. and diethyl phosphate (also known as ethyl acid phosphate) (trade name: JP-502, manufactured by Johoku Chemical Co., Ltd.) 0.01 g (dehydration condensation catalyst bis (2-ethylhexanoic acid)) The same mass as tin) was added and stirred for 20 minutes, and then cooled to 30 ° C. Next, 210 g of methanol and 90 g of ethanol were added and stirred for 20 minutes. After standing for 12 hours, the alcohol layer was removed, the pressure was reduced to 100 Pa, the temperature was raised to 115 ° C. and desolubilization was performed for 5 hours. 148.8 g of siloxane resin was obtained.

At this time, the ratio of the methoxy group of KBM-5102 converted to silanol with respect to the total amount of raw material siloxane and silane compound of the repeating unit of polysiloxane was 4.2% by mass.
From the hydrogen integration ratio of NMR, the number of repeating units of 3-acryloxypropylmethylsiloxane of this resin was 1.9% by mass. The ethylenically unsaturated bond concentration was measured by the following method.

-Measurement method of ethylenically unsaturated bond concentration-
The number of repeating units of 3-acryloxypropylmethylsiloxane was calculated from the hydrogen integration ratio of NMR. In the NMR chart, an integral value near 6 ppm of hydrogen of an ethylenically unsaturated bond, an integral value around 7.5 ppm of hydrogen of a phenyl group, and an integral value of around 0.1 ppm of hydrogen of a methyl group were used. Measurement solvent was CDCl _3.

In the resin prepared above, bonded to a vinyl group of the calculated hydrogen integral ratio (derived from methyl groups of diphenylsiloxane ^{1 H)} :( from phenyl dimethylsiloxane ^{1 H)} :( 3- acryloxypropyl methyl siloxane NMR to ^{1 H) = 10.00: 27.89:} 0.61, was. The number of hydrogen contained in each repeating unit is 10 for diphenylsiloxane, 6 for dimethylsiloxane, and 3 for hydrogen bonded to the vinyl group of 3-acryloxypropylmethylsiloxane. The number of repeating units of loxypropylmethylsiloxane was calculated to be 1.9% by mass.

(Manufacturing example of light control material)
7.0 g of energy beam curable polysiloxane resin obtained in the above “Production Example of Energy Beam Curable Silicone Resin”, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide as a photopolymerization initiator ( Product name: Irgacure 819, manufactured by BASF Japan Co., Ltd.) 0.2 g, and 3.0 g of the light control suspension obtained in the above “Production Example of Light Control Suspension” were added and mixed mechanically for 1 minute. A light-modulating material was manufactured.

(Manufacturing example of light control film)
Transparent conductive resin made of PET film (300R, manufactured by Toyobo Co., Ltd., thickness 125 μm, surface electrical resistance value 200 to 700Ω) coated with ITO (indium tin oxide) transparent conductive film (thickness 300 mm) Two substrates were prepared. A primer layer was formed on each of the two transparent conductive resin substrates. The primer layer was formed by the following method.

  AY42-151 (trade name, Toray Dow Corning Co., Ltd.) is dissolved in a mixed solvent of isopropyl alcohol: 1-methoxy-2-propanol = 3: 7 so as to be 1.0% by mass and used for forming a primer layer. A coating solution was prepared. AY42-151 contains a photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone).

On the transparent conductive film of the transparent conductive resin substrate with ITO, the primer layer forming coating solution is applied over the entire surface using a microgravure method (mesh # 150) to form a primer layer, After drying at 30 s, 60 ° C./30 s, and 70 ° C./1 min, a primer layer was formed by photocuring with UV irradiation 1000 mJ / cm ² (metal halide lamp).
The obtained primer layer had a thickness of 73 nm. The film thickness of the primer layer was measured using an instantaneous spectrophotometer F-20 (manufactured by Filmetrics Co., Ltd.).

On the transparent conductive resin substrate on which the primer layer was formed, the light control material obtained above was applied over the entire surface to form a coating layer. Next, the transparent conductive film in the other transparent conductive resin substrate with a primer layer was laminated and adhered to the coating layer so as to face the coating layer, and then 4000 mJ / cm ² using a metal halide lamp. Ultraviolet rays were irradiated from the PET film side of the laminated transparent conductive resin substrate. As a result, a light control film was obtained in which the light control suspension was dispersed and formed as spherical droplets in an ultraviolet cured resin matrix. The thickness of the light control layer in the light control film was 90 micrometers, and the total thickness of the light control film was 340 micrometers.

  An SEM photograph was taken from one surface direction of the obtained light control film, the diameters of the droplets of a plurality of arbitrarily selected light control suspensions were measured, and the average value was calculated. The average diameter of the droplets of the light control suspension was 3 μm.

[Comparative Example 0]
<Measurement of interference fringe wavelength>
Near-infrared light was incident on the obtained light control film so that the incident angle was 0 °, and a near-infrared spectrum in the region of 8000 to 4000 cm ⁻¹ was observed. The measurement was performed using FT / IR-6000 (manufactured by JASCO Corporation, InGaAs detector, resolution 4 cm ⁻¹ ). However, interference fringes are generated, and it is impossible to confirm the peak observed in the vicinity of 6050 cm ^−1, which is the internal standard, and the absorption peak of the first overtone derived from the C═C bond observed in the vicinity of 6170 cm ^−1. It was. The wavelength of the interference fringes was 0.26 μm.

[Example 1]
<Measurement of curing rate>
The PET film surface of the light control film obtained above was reciprocated 10 times by applying a load of 200 g to a cotton swab soaked with hexafluoroisopropanol (HFIP) to dissolve the PET film. When the maximum height (Ry) of the surface roughness of the dissolved part was measured using a stylus type step / surface shape measuring device (manufactured by AMBiOS, XP-2), it was 2.5 μm.

Near-infrared light was incident on this dissolved portion so that the incident angle was 0 ° with respect to the normal line of the light control film, and a near-infrared spectrum in the region of 8000 to 4000 cm ⁻¹ was measured. .
Further, a near-infrared spectroscopic spectrum was similarly measured by sandwiching an uncured light control material with a PET film having the surface dissolved with a cotton swab soaked with HFIP as described above.

Since the peak observed in the vicinity of 6050 cm ⁻¹ is a peak derived from a component that does not change before and after curing, the first overtone derived from the C═C bond observed in the vicinity of 6170 cm ⁻¹ using this peak as an internal standard. From the ratio between the absorption peak area and the internal standard peak area, the curing rate was calculated by the following formula. The curing rate of the light control film produced above was 94.3%.

Curing rate (%) = [1- (A _x / B _x ) / (A ₀ / B ₀ )] × 100

A ₀ represents the first overtone absorption peak area derived from the C═C bond when uncured (light control material), A _x represents the area after curing, and B ₀ represents the internal standard peak area when uncured. , B _x represents the area after curing. When completely cured, A _x = 0.

<Evaluation of light transmittance>
Next, in order to energize for voltage application, a part of the light control layer was removed from the end of the light control film, and the transparent conductive film at the end was exposed (see FIG. 4). An AC voltage was applied to the light control film, and a spectroscopic color difference meter SZ-Σ90 (manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the Y value (%) measured with an A light source and a viewing angle of 2 degrees. Measured as transmittance.

The light transmittance of the light control film was 1.0% when no AC voltage was applied (not applied: T _off ). Further, the light transmittance (T _on ) of the light control film when an AC voltage of 100 Hz (effective value) of 50 Hz was applied was 49%, and the difference in light transmittance between when an electric field was applied and when no electric field was applied (ΔT = T _on- T _off ) was as large as 48 and was good.

<Evaluation of heat resistance>
Furthermore, about the light control film after storing at 110 degreeC for 2 hours, the light transmittance was measured by the method similar to the measurement of the said light transmittance, and heat resistance (%) was calculated | required from following Formula. As a result, the heat resistance of the light control film was as good as 95.4%.
Heat resistance = (ΔT after heat test) / (ΔT before heat test) × 100

[Example 2]
The PET film surface of the light control film produced in the same manner as in Example 1 was reciprocated 10 times by applying a load of 200 g to a cotton swab soaked with hexafluoroisopropanol (HFIP) to dissolve the PET film. Near-infrared light was incident on this dissolved portion so that the incident angle of near-infrared light was 30 ° with respect to the normal line of the light control film, and a near-infrared spectrum was measured. The curing rate calculated by the above method from each peak area at this time was 94.4%, and the heat resistance was 95.4%.
It was.

  In the second example in which the incident angle of near-infrared light was 30 °, generation of interference fringes was suppressed compared to the first example in which the incident angle was 0 °. This is thought to be because the probability that light having repeated one or several rounds of reflection on the substrate film surface enters the detector by tilting the incident angle is reduced.

[Example 3]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the incident angle of infrared rays with respect to the normal line of the light control film was 45 °. The curing rate at this time was 94.4%, and the heat resistance was 95.4%. Further, in Example 3 in which the incident angle of near-infrared light was 45 °, generation of interference fringes was suppressed compared to Example 1 in which the incident angle was 0 °.

[Example 4]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the incident angle of infrared rays with respect to the normal line of the light control film was 60 °. The curing rate at this time was 94.3%, and the heat resistance was 95.4%.
Further, in Example 4 in which the incident angle of near-infrared light was 60 °, generation of interference fringes was suppressed compared to Example 1 in which the incident angle was 0 °.

  As shown in Examples 1 to 4, it can be seen that according to the method for measuring the curing rate of the light control film of the present invention, the curing rate is measured with good reproducibility. Moreover, it turns out that the light control film of Examples 1-4 whose cure rate obtained by the measuring method of the cure rate of the light control film of this invention is 75 to 100% is excellent in heat resistance.

[Example 5]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was set to 5000 mJ / cm ² . At this time, Ry was 2.4 μm, the curing rate was 95.4%, and the heat resistance was 97.3%.

[Example 6]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was 3500 mJ / cm ² . At this time, Ry was 2.7 μm, the curing rate was 89.4%, and the heat resistance was 93.5%.

[Example 7]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was set to 3000 mJ / cm ² . At this time, Ry was 2.3 μm, the curing rate was 85.1%, and the heat resistance was 91.8%.

[Example 8]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was 2500 mJ / cm ² . At this time, Ry was 2.5 μm, the curing rate was 82.9%, and the heat resistance was 91.8%.

As shown in Examples 5 to 8, according to the method for measuring the curing rate of the present invention, the curing rate corresponds to the irradiation rate of ultraviolet rays. From the above, it can be seen that according to the method of measuring the curing rate of the present invention, the curing rate of the light control film is measured with high accuracy.
Moreover, it turns out that the light control film of Examples 5-8 whose cure rate obtained by the measuring method of the cure rate of the light control film of this invention is 75 to 100% is excellent in heat resistance.

[Comparative Example 1]
The light control material was sandwiched between two KBr plates, and the infrared spectrum in the region of 4000 to 400 cm ⁻¹ was measured. For the measurement, FTS-6000 (manufactured by BIORAD, MCT detector, resolution 4 cm ⁻¹ ) was used. In addition, the light control film produced above was peeled off from the transparent conductive resin substrate, sandwiched between two KBr plates, and the infrared spectrum was measured in the same manner. C = C stretching vibration is fingerprint area of 1618cm ^-1 and a clear peak in before and after curing in the vicinity 1636 cm ^-1 is not observed, the calculation of the hardening rate was not possible.

[Comparative Example 2]
Put light modulating material in a glass microtube ^was measured Raman spectrum in the region of 3500 cm -1 to 50 cm ^-1. The measurement was performed using RFS100 (manufactured by BRUKER, Nd · YAG laser (1064 nm)) with a laser output of 300 mW and an integration count of 512 times. Only a broad scattering peak with few features over almost the entire wavenumber region was observed, and the cure rate could not be calculated.

[Comparative Example 3 of Light Control Film]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was 2000 mJ / cm ² . At this time, Ry was 2.5 μm, the curing rate was 73.3%, and the heat resistance was 86.4%.

[Comparative Example 4 of Light Control Film]
The curing rate and heat resistance were measured in the same manner as in Example 2 except that the irradiation amount of ultraviolet rays for curing the light control film was set to 1500 mJ / cm ² . At this time, Ry was 2.7 μm, the curing rate was 68.8%, and the heat resistance was 81.2%.

  By contrast with Examples 1-8 and Comparative Examples 3 and 4, the light control film having a curing rate of less than 75% obtained by the method for measuring the curing rate of the light control film of the present invention has a sharp decrease in heat resistance. You can see that

  In FIG. 7, the relationship between the irradiation amount of the ultraviolet-ray in Example 2, 5-8, and Comparative Examples 3 and 4 and the hardening rate measured by the method of this invention is shown on a graph. As shown in FIG. 7, the curing rate increases as the amount of UV irradiation increases, and the error from the approximate curve is small. Therefore, the method for measuring the curing rate of the present invention is rapid and simple. It can be seen that this method is excellent in reliability but also in reliability.

[Comparative Example 5 of Light Control Film]
A polysiloxane resin was synthesized in the same manner as in Example 1 except that the methoxy group of KBM-5102 was used as it was for the synthesis of siloxane resin without being converted to silanol, and the number of repeating units of 3-acryloxypropylmethylsiloxane was Of polysiloxane resin having a weight average molecular weight of 45,000 and a viscosity of 13,500 was obtained. The curing rate of the light control film produced using this polysiloxane resin was 93.4%, but the heat resistance was 75.2%. At this time, Ry was 2.3 μm.

[Comparative Example 6 of Light Control Film]
The charged raw materials were 48.0 g of X-21-3114, 171.0 g of X-21-3193B, 6.0 g obtained by converting the methoxy group of KBM-5102 to silanol, and 109.0 g of KBM-31. Except for the above, a polysiloxane resin was synthesized in the same manner as in Example 1 to obtain 159.4 g of a polysiloxane resin having a weight average molecular weight of 66,600 and a viscosity of 27,600.
At this time, the ratio of the methoxy group of KBM-5102 converted to silanol with respect to the total amount of raw material siloxane and silane compound of the repeating unit of polysiloxane was 2.3% by mass. From the NMR hydrogen integration ratio, the number of repeating units of 3-acryloxypropylmethylsiloxane of this resin was 1.2% by mass.
Moreover, although the hardening rate of the light control film produced using this polysiloxane resin was 92.9%, heat resistance was 83.4%. At this time, Ry was 2.6 μm.

[Comparative Example 7 of Light Control Film]
The charged materials were 46.0 g of X-21-3114, 164.0 g of X-21-3193B, 47.0 g of KBM-5102 converted to silanol, and 105.0 g of KBM-31. Except for the above, a polysiloxane resin was synthesized in the same manner as in Example 1 to obtain 169.7 g of a polysiloxane resin having a weight average molecular weight of 48,700 and a viscosity of 9,100.
At this time, the ratio of the methoxy group of KBM-5102 converted to silanol with respect to the total amount of raw material siloxane and silane compound of the repeating unit of polysiloxane was 18.4% by mass. From the NMR hydrogen integration ratio, the number of repeating units of 3-acryloxypropylmethylsiloxane of this resin was 7.6% by mass.
Moreover, although the cure rate of the light control film produced using this polysiloxane resin was 94.4%, heat resistance was 21.2%. At this time, Ry was 2.4 μm.

  By contrast with Examples 1-8 and Comparative Examples 5-7, even if the hardening rate obtained by the measuring method of the hardening rate of the light control film of this invention is 75-100%, the said high It can be seen that when the number of repeating units having a (meth) acryloyl group in the molecular medium is outside the range of 1.3 to 5.0% by mass of the total number of repeating units, the heat resistance is drastically decreased.

DESCRIPTION OF SYMBOLS 1 Light control layer 2 Resin matrix 3 Droplet 4 Transparent conductive resin base material 5a Transparent conductive film 5b Transparent resin base material 6 Primer layer 7 Power supply 8 Switch 9 Dispersion medium 10 Light adjustment particle 11 Incident light 12 The light control layer is removed. Exposed surface 13 of transparent conductive film Conductive wire for applying voltage to transparent conductive film

Claims (12)

In a light control film formed by sandwiching a light control layer comprising a resin matrix that is a cured product of a polymer medium and a light control suspension dispersed in the resin matrix between two transparent conductive resin substrates, It is a method of measuring the curing rate of the resin matrix by a near infrared spectrum,
When interference fringes occur when near-infrared light is transmitted through the light control film, a near-red light is obtained using a second light control film provided with two transparent conductive resin substrates that satisfy the following formula (I). A method for measuring a curing rate of a resin matrix in a light control film, which measures an outer spectral spectrum.
Formula (I):
Maximum height (Ry) of surface roughness in the irradiation region of the near infrared light ≧ wavelength λ × 1/2 of the interference fringes   The surface of the two transparent conductive resin substrates in the region irradiated with the near-infrared light is dissolved by a solvent capable of dissolving the transparent conductive resin substrate to satisfy the formula (I). The method for measuring the curing rate of the light control film according to claim 1, wherein the surface of the transparent conductive resin substrate is processed.   3. The method for measuring a curing rate of a light control film according to claim 2, wherein when the two transparent conductive resin substrates are made of polyethylene terephthalate, the solvent is hexafluoroisopropanol.   The measuring method of the hardening rate of the light control film of any one of Claims 1-3 which injects the said near infrared light at 30-60 degrees with respect to the surface of the said light control film. 1st light control film which sandwiches the light control layer containing the resin matrix which is the hardened | cured material of a polymer medium, and the light adjustment suspension disperse | distributed in the said resin matrix with two transparent conductive resin base materials A step of producing
When interference fringes are generated when the near-infrared light is transmitted through the first light control film, a second light control film including two transparent conductive resin substrates satisfying the following formula (I) A step of producing
A step of transmitting near infrared light to the second light control film to measure a near infrared spectrum, and measuring a curing rate of the resin matrix in the second light control film;
Applying the curing rate obtained by the measurement to the previously determined relationship between the curing condition and the curing rate of the polymer medium, the curing condition of the polymer medium that falls within a predetermined curing rate range The process of deriving
A dimming layer comprising a resin matrix obtained by curing the polymer medium under the derived curing conditions, and a light control suspension dispersed in the resin matrix is formed of two transparent conductive resin substrates. Producing a sandwiched third light control film;
The manufacturing method of the light control film which has these.
Formula (I):
Maximum height (Ry) of surface roughness in the irradiation region of the near infrared light ≧ wavelength λ × 1/2 of the interference fringes   In the step of producing the second light control film, the near red color on the surface of the two transparent conductive resin base materials of the first light control film by a solvent capable of dissolving the transparent conductive resin base material. The manufacturing method of the light control film of Claim 5 which melt | dissolves the area | region to which external light is irradiated, and processes the surface of the said transparent conductive resin base material so that the said Formula (I) may be satisfy | filled.   The method for producing a light control film according to claim 6, wherein when the two transparent conductive resin substrates are composed of polyethylene terephthalate, the solvent is hexafluoroisopropanol.   The process according to any one of claims 5 to 7, wherein in the step of measuring the curing rate, the near infrared light is incident on the surface of the second light control film at 30 to 60 °. Manufacturing method of optical film.   The method for producing a light control film according to any one of claims 5 to 8, wherein the predetermined curing rate is 75 to 100%.   The polymer medium has a polysiloxane structure having a (meth) acryloyl group, and the number of repeating units having the (meth) acryloyl group is 1.3 to 5.0% by mass of the total number of repeating units. The manufacturing method of the light control film of any one of Claims 5-9.   The method for producing a light control film according to any one of claims 5 to 10, wherein the polymer medium has a weight average molecular weight of 35,000 to 60,000. Two transparent conductive resin substrates;
A light control layer including a resin matrix, which is a cured product of a polymer medium, sandwiched between the two transparent conductive resin substrates, and a light control suspension dispersed in the resin matrix; ,
The polymer medium has a polysiloxane structure having a (meth) acryloyl group, and the number of repeating units having the (meth) acryloyl group is 1.3 to 5.0% by mass of the total number of repeating units,
The light control film whose cure rate of the said resin matrix obtained by the measuring method of the cure rate of any one of Claims 1-4 is 75 to 100%.