JP6048011B2 - Light control material and light control film - Google Patents

Description

  The present invention relates to a light control material and a light control film.

  A dimming glass containing a light conditioning suspension was first invented by Edwin. Land, and its form is a liquid between two transparent conductive substrates with a narrow spacing. The light control suspension in a state is injected (see, for example, Patent Document 1). According to Edwin Land's invention, the liquid light-regulating suspension injected between two transparent conductive substrates is light dispersed in the suspension when no electric field is applied. Due to the Brownian motion of the conditioning particles, most of the incident light is reflected, scattered or absorbed by the light conditioning particles and only a small portion is transmitted. Robert L. Sax et al. Synthesized light-controlling particles using a monomer having a hydroxyl group or other functional group that has high affinity with the particles as a method for stably dispersing the light-controlling particles in the medium. A method using a dispersed polymer has been proposed (see, for example, Patent Documents 2 and 3). In addition, it has been proposed that trimellitic acid ester is effective as a medium (see, for example, Patent Document 4).

US Pat. No. 1,955,923 U.S. Pat. No. 4,164,365 U.S. Pat. No. 4,273,422 US Pat. No. 5,461,506

However, in the method of suspending the light control particles described in Patent Documents 2 to 4, when the electric field is applied when the configured light control film is placed in a low temperature environment (for example, 0 ° C. or less), The change from the colored state to the transparent state and the rate of change from the transparent state to the colored state when the electric field is turned off is slow, that is, the response of the mutual change between the transparent state and the colored state due to ON / OFF of the electric field There was a problem of slowing down.
The present invention provides a light control material excellent in the response speed of a mutual change between a transparent state and a colored state by ON / OFF of a voltage even in a low temperature environment, and a light control film configured using the same. Let it be an issue.

Specific means for solving the above problems are as follows.
<1> A polymer medium curable by energy ray irradiation, a (meth) acrylate having a polysiloxane structure and a first structural unit that is dispersed in the polymer medium and derived from a (meth) acrylate having a hydroxy group copolymers comprising a second structural unit derived from, as well as a light control suspension containing light control particles seen including, other than the first structural unit and the second structural unit in the copolymer The light control material whose ratio of the other structural unit of is 20 mol% or less .

<2> The copolymer has a molar ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) of 10/90 to 70/30 <1. dimming materials described in>.

<3> The light control material according to <1> or <2>, wherein the copolymer has an alkyl sulfide structure having a hydroxy group at least at one of a β-position and a γ-position at a terminal.

<4> Two conductive resin base materials and a light control layer sandwiched between the two conductive resin base materials, wherein the light control layer is dispersed in the resin matrix and the resin matrix A copolymer comprising a first structural unit derived from a (meth) acrylate having a hydroxy group and a second structural unit derived from a (meth) acrylate having a polysiloxane structure, and light containing light adjusting particles control suspension and, seen including a said first structural unit and the second light control film ratio is not more than 20 mole% of other structural units other than structural units in the copolymer.

<5> The copolymer has a molar ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) of 10/90 to 70/30 <4. The light control film as described in>.

<6> The light control film according to <4> or <5>, wherein the copolymer has an alkyl sulfide structure having a hydroxy group at least at one of a β-position and a γ-position at a terminal.

  ADVANTAGE OF THE INVENTION According to this invention, the light control material excellent in the response speed of the mutual change between the transparent state and coloring state by ON / OFF of a voltage also in a low temperature environment, and a light control film comprised using this are provided. be able to.

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 the light when the electric field is not applied. It is a schematic diagram which shows the mode of the droplet 3 of adjustment suspension. FIG. 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 the light when the electric field is applied. It is a schematic diagram which shows the mode of the droplet 3 of adjustment suspension.

In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. . Moreover, the numerical range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. Further, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.
Further, “(meth) acrylate” means at least one of “acrylate” and “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means at least one of “acryl” and “methacryl” corresponding thereto.

<Light control material>
The light control material of the present invention comprises a polymer medium curable by irradiation with energy rays, a first structural unit and a polysiloxane structure derived from a (meth) acrylate having a hydroxy group dispersed in the polymer medium. A copolymer containing a second structural unit derived from (meth) acrylate having, and a light control suspension containing light control particles. The said light control material may contain the other component as needed. Dispersion stability of light control particles is improved by including a copolymer having a specific structure in the light control suspension, and a transparent state and a colored state by ON / OFF of voltage even in a low temperature environment (for example, 0 ° C. or less). The light control material which is excellent in the response speed (hereinafter also referred to as “low temperature responsiveness”) of the mutual change between the two is obtained.

[Light control suspension]
The light control suspension is at least one kind of a copolymer including a first structural unit derived from a (meth) acrylate having a hydroxy group and a second structural unit derived from a (meth) acrylate having a polysiloxane structure. And at least one kind of light adjusting particles, which are dispersed as droplets in the polymer medium. The light adjusting suspension may contain other components as required. For example, the copolymer functions as a resin dispersant in the light control suspension, improves the dispersion stability of the light control particles, and as a result, improves the low-temperature response.

(Copolymer)
The copolymer is a copolymer including a first structural unit derived from a (meth) acrylate having a hydroxy group and a second structural unit derived from a (meth) acrylate having a polysiloxane structure (hereinafter, Sometimes called “specific copolymer”). From the viewpoint of the dispersion stability of the light control particles and the responsiveness at low temperature, the molar ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) is 10 / 90 to 70/30 is preferable, 15/85 to 65/35 is more preferable, and 15/85 to 60/40 is still more preferable. Here, the structural unit refers to a repeating unit derived from a monomer contained in the copolymer. When the molar ratio of the first structural unit is 10 mol% or more in the total amount of the first structural unit and the second structural unit, the dispersion stability of the light control particles becomes better, and the dispersion of the light control particles There is a tendency that the low temperature response improves. On the other hand, when the molar ratio of the first structural unit is 70 mol% or less in the total amount of the first structural unit and the second structural unit, the viscosity of the copolymer does not increase excessively, and the low-temperature response is further improved. There is a tendency to excel.

  The specific copolymer is used as a flowable dispersion medium constituting a light adjusting suspension in which light adjusting particles are dispersed. Such a specific copolymer is preferably one that can be completely phase-separated from a polymer medium to be described later and a resin matrix that is a cured product thereof, or one that can be partially phase-separated. More preferably, the liquid in which the light control particles are dispersed in a flowable state, is selectively attached to and coated on the light control particles, and the light control particles are phase-separated during phase separation from the polymer medium. Liquid that acts to move to the droplet phase, has low electrical conductivity, low affinity with the polymer medium, and approximates the refractive index of the resin matrix formed from the polymer medium when used as a light control film The specific copolymer.

  The specific copolymer is preferably used, for example, when preparing a light adjusting suspension and stably dispersing the light adjusting particles. By using the specific copolymer containing the first structural unit and the second structural unit, the dispersion stability of the light control particles is improved, and a light control material excellent in low temperature response can be obtained. Such a specific copolymer may contain other structural units as required in addition to the first structural unit and the second structural unit.

  The (meth) acrylate having a hydroxy group constituting the first structural unit is not particularly limited as long as it has at least one hydroxy group and a polymerizable group. Examples of the (meth) acrylate having a hydroxy group include (meth) acrylate having at least one hydroxy group in the alkyl group portion of the (meth) acrylic acid alkyl ester, and the alkyl of the (meth) acrylic acid alkyl ester. A (meth) acrylate having one hydroxy group in the base portion is preferred, and a hydroxyalkyl (meth) acrylate represented by the following general formula (I) is more preferred.

In general formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkylene group having 2 to 8 carbon atoms. In the formula (I), R ¹ is a hydrogen atom or a methyl group, and preferably a methyl group. Further, the alkylene group represented by R ² may be cyclic, linear or branched. Among these, the alkylene group represented by R ² is preferably branched or linear, and more preferably linear. From the viewpoint of heat resistance, the alkylene group represented by R ² preferably has 2 to 4 carbon atoms, and more preferably a linear alkylene group having 2 to 4 carbon atoms.
When R ¹ and R ² satisfy the preferable conditions as described above, the dispersibility of the light adjusting particles can be further increased, and the heat resistance can also be improved.

  Specific examples of the compound represented by the general formula (I) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). Acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 7-hydroxyheptyl (meth) acrylate, 8-hydroxy Examples include octyl (meth) acrylate. Among these, at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is preferable. Is more preferable.

  The (meth) acrylate having a polysiloxane structure constituting the second structural unit is not particularly limited as long as it is a (meth) acrylic acid ester having a polysiloxane structure.

The repeating unit in the polysiloxane structure may be a dialkylsiloxane, a diarylsiloxane, or a monoalkylmonoarylsiloxane. The alkyl group in the siloxane structure is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Examples of the aryl group in the siloxane structure include a phenyl group and a naphthyl group, and a phenyl group is preferable.
Specific examples of the repeating unit in the polysiloxane structure include dimethylsiloxane, diphenylsiloxane, and methylphenylsiloxane.

The (meth) acrylate having a polysiloxane structure is preferably a compound represented by the following general formula (II).

In the general formula (II), ^{R 3} represents an alkyl group having 1 to 4 carbon atoms. R ⁴ each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group. R ⁵ represents an alkylene group having 1 to 3 carbon atoms. R ⁶ represents a hydrogen atom or a methyl group. n is the number of repeating siloxane structural units and represents a number of 1 to 200.

In the general formula (II), R ⁶ is preferably a methyl group. R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. R ³ is preferably an alkyl group having 1 to ³ carbon atoms, and more preferably a methyl group.

  As a compound represented by the said formula (II), it is preferable that a weight average molecular weight (Mw) is 500-10000, It is more preferable that it is 500-8000, It is more preferable that it is 500-6000. When the weight average molecular weight is in this range, a light control material having excellent low temperature response can be realized.

The specific copolymer may further include other structural units other than the first structural unit and the second structural unit as necessary. The monomer that forms the other structural unit is not particularly limited as long as it is a monomer copolymerizable with a (meth) acrylate having a hydroxy group and a (meth) acrylate having a siloxane structure. Among them, the monomer that forms other structural units is preferably alkyl (meth) acrylate, more preferably alkyl (meth) acrylate having 4 to 20 carbon atoms, from the viewpoint of dispersibility of the light control particles, An alkyl (meth) acrylate having 8 to 16 carbon atoms is more preferable, and an alkyl (meth) acrylate having 10 to 14 carbon atoms is particularly preferable.
Here, the alkyl (meth) acrylate having 4 to 20 carbon atoms is an alkyl (meth) acrylate having an alkyl group having 4 to 20 carbon atoms. The alkyl group in the alkyl (meth) acrylate is not particularly limited, and may be linear, branched or cyclic. Of these, the alkyl group is preferably linear or branched.

  Specific examples of alkyl (meth) acrylates forming other structural units include 2-methylpropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, and hexyl. (Meth) acrylate, 2,4,6-trimethylheptyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, Undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate Over DOO, nonadecyl (meth) acrylate, eicosyl (meth) acrylate. Among these, hexyl (meth) acrylate, 2,4,6-trimethylheptyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl ( At least one selected from the group consisting of (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, and pentadecyl (meth) acrylate is preferable, and 2,4,6-trimethylheptyl (meth) ) At least one selected from the group consisting of acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate and tridecyl (meth) acrylate is more preferred.

  When the said specific copolymer contains another structural unit, it is preferable that the content ratio is 20 mol% or less in all the structural units, and it is more preferable that it is 10 mol% or less. Although a minimum in particular is not restrict | limited, It is preferable that it is 1 mol% or more.

  The specific copolymer preferably has an alkyl sulfide structure having a hydroxy group at at least one of β-position and γ-position at the terminal, and has an alkyl sulfide structure having a hydroxy group at the β-position and γ-position at one terminal. It is more preferable to have a C3-C6 alkyl sulfide structure having a hydroxy group at the β-position and γ-position at one end. By having a hydroxy group at the terminal portion of the copolymer, the dispersibility of the light control particles tends to be more effectively improved. This can be considered as follows, for example.

  In the specific copolymer, a functional group (preferably a hydroxy group) having an affinity for the light adjusting particles described later has a smaller bulky functional group in the vicinity of the specific polymer. It is considered that the closer to the end of the polymer chain, the stronger the interaction due to the affinity, and the more effective the aggregation of the light control particles and the prevention of sedimentation.

  The specific copolymer having an alkyl sulfide structure having a hydroxy group in at least one of β-position and γ-position at at least one end, for example, links an alkyl mercaptan derivative having a hydroxy group in at least one of β-position and γ-position. It can be obtained by carrying out a radical polymerization reaction of (meth) acrylic acid ester as a transfer agent.

  In general, when a copolymer is synthesized from two or more types of monomers by radical copolymerization, a monomer having a functional group (hereinafter also referred to as “affinity functional group”) having an affinity for the light control particle is used as a polymer chain. It is difficult to perform position control of which position to introduce. Although a certain degree of selectivity can be expected by using a monomer having a bulky substituent or a monomer having low reactivity, depending on the ratio of the monomer and the polymerization conditions, there is no co-functional group in the polymer chain. There is a possibility that a polymer is formed or the affinity functional group is located near the center of the polymer chain.

On the other hand, the specific copolymer obtained by performing radical polymerization reaction of (meth) acrylic acid ester using an alkyl mercaptan derivative having a hydroxy group at at least one of β-position and γ-position as a chain transfer agent as described above Is considered to be more effective in suppressing aggregation and sedimentation of the light control particles, since the affinity functional group is introduced into the polymer chain end away from the bulky functional group with high probability.
In addition, the specific copolymer having an excellent effect of suppressing aggregation and sedimentation of the light adjusting particles can stably disperse the light adjusting particles even with a smaller addition amount. Can be widened. Moreover, if the light control particles can be stably dispersed, the transmittance when a light control film is formed will be excellent.

  Specific examples of alkyl mercaptan derivatives having a hydroxy group in at least one of β-position and γ-position include 3-mercapto-1,2-propanediol, 1-mercapto-2,3-dihydroxybutane, 1-mercapto-2, Examples include 3-dihydroxyhexane.

  The molecular weight of the specific copolymer is not particularly limited. The molecular weight of the specific copolymer is preferably a standard polystyrene equivalent weight average molecular weight of 500 to 20,000 as measured by gel permeation chromatography (GPC) from the viewpoint of low temperature response, and 1,000 to 15, More preferably, it is 000. Further, the viscosity of the specific copolymer is preferably 30 mPa · s to 2,000 mPa · s, more preferably 50 mPa · s to 1,800 mPa · s at 25 ° C. The viscosity at 25 ° C. is measured with an E-type viscometer.

  The specific copolymer can be prepared by copolymerizing a monomer mixture containing (meth) acrylate having a hydroxy group and (meth) acrylate having a polysiloxane structure by a commonly used polymerization method. For example, a monomer mixture containing a (meth) acrylate having a hydroxy group and a (meth) acrylate having a polysiloxane structure can be prepared by radical polymerization using a polymerization initiator, and at least in the β-position and γ-position. On the other hand, radical polymerization is preferably performed using an alkyl mercaptan derivative having a hydroxy group as a chain transfer agent.

  The polymerization initiator used for preparation of the specific copolymer is not particularly limited and can be appropriately selected from commonly used polymerization initiators. Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. Specific examples include azoisobutyronitrile and di-tert-butyl peroxide.

  The specific copolymer obtained as described above is preferably subjected to a purification step after synthesis. Examples of the purification method include liquid separation purification using alcohols such as methanol, ethanol, and propanol, and a method of removing low molecular components by distillation under a high vacuum of 10 Pa or less called molecular distillation.

  The content of the specific copolymer in the light adjusting suspension can be appropriately selected according to the content of the light adjusting particles described later. In general, the content of the specific copolymer is preferably 1000 parts by mass to 100000 parts by mass, and more preferably 1200 parts by mass to 10,000 parts by mass with respect to 100 parts by mass of the light control particles.

(Light control particles)
The light control suspension. It contains at least one kind of light adjusting particles. Examples of the light control particles include precursors pyrazine-2,3-dicarboxylic acid dihydrate, pyrazine-2,5-dicarboxylic acid dihydrate, pyridine-2,5-dicarboxylic acid monohydrate. A needle-like small crystal of polyiodide obtained by reacting one substance selected from the group consisting of substances, iodine and iodide with nitrocellulose is preferably used.
Examples of iodide include calcium iodide. Examples of the polyiodide thus obtained include those represented by the following general formula.
_{CaI 2 (C 6 H 4 N} 2 O 4) · xH 2 O (x: 1~2)
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)
These polyiodides are preferably acicular crystals.

  Further, as light adjusting particles used in the light adjusting suspension for light control film, US Pat. No. 2,041,138 (EH Land), US Pat. No. 2,306,108 (Land) Et al., 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.

  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 nm to 625 nm, more preferably 250 nm to 550 nm, and further preferably 300 nm 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 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 images. It can be calculated as the arithmetic mean value of the major axis and minor axis of the adjusted particles. 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 adjusting particles, 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) to 220 nm is preferable, 140 nm to 210 nm is more preferable, and 145 nm to 205 nm is still more preferable.

  This Z average value is measured by a particle size distribution meter different from the Zetasizer Nano series based on, for example, the optical correlation method or the dynamic light scattering method, or light measured by an electron microscope such as the transmission electron microscope described above. It is known to show a good correlation with the major axis and minor axis of the adjusted particles, and is suitable as an index for evaluating the particle size.

The produced light control particles may include unreacted materials and by-products, small particles and large particles, particles having a small aspect ratio, and large particles. Usually, it is preferably used after purification. As this purification method, for example, there is a method of performing centrifugation. Centrifugation conditions depend on the amount to be treated, but 3000G to 20000G is preferable. The number of treatments is preferably 2 or more. After centrifugation, the supernatant is decanted and discarded, and an organic solvent that can be dispersed without agglomeration of particles is added. At this time, the organic solvent to be added is not limited, but examples thereof include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, isoamyl acetate, hexyl acetate, acetone, ethyl methyl ketone, isobutyl ketone, etc. Ethyl, propyl acetate, butyl acetate, pentyl acetate, isoamyl acetate, and hexyl acetate can be suitably used, and it is preferable that one or more of these solvents are contained. These solvents may be used alone or in combination of two or more. Moreover, when performing the centrifugation process twice or more, you may use the solvent which dissolved nitrocellulose for the first centrifugation process. At this time, the concentration of nitrocellulose is 3% by mass to 20% by mass, preferably 5% by mass to 15% by mass. Moreover, after adding a solvent, it is good to process with a homogenizer or an ultrasonic wave so that light control particles can be disperse | distributed in a solvent.
The light adjusting particle dispersion can be obtained as described above.

As a method for obtaining the concentration of the light control particles in the light control particle dispersion, there is a method in which a small amount of the light control particle dispersion is sampled and the solid weight remaining after heating and drying is used as the amount of particles to calculate the concentration.
As a more accurate concentration determination method, for example, a method of measuring the density of the light control particle dispersion and obtaining the concentration from the density value can be mentioned. Specifically, in the method for producing a light control suspension, a step of measuring the density of the light control particle dispersion, and a step of calculating the concentration of the light control particle dispersion based on the measured density Can be provided. If there is a difference between the density of the particles and the solvent as the medium, it is considered that there is a correlation between the concentration of the particles and the density of the dispersion. The apparatus for measuring the density of the solvent and the dispersion is not particularly limited. For example, if an oscillating digital density meter manufactured by Anton Paar is used, it is possible to obtain the density from the 4th place to the 6th place after the decimal point. .

  In addition, the expression expressing the relationship between the density of the light control particle dispersion and the particle concentration is expressed as follows: the density of the light control particles, the density of the solvent, and the density of the dispersion are Dp, Ds, and Dsus, respectively. If the concentration is Cp, the volume of the light control particle dispersion per unit weight can be obtained if it is the sum of the volume of the particles and the solvent. The weights of the light control particles and the solvent contained in the unit weight of the light control particle dispersion are Cp / 100 and (100−Cp) / 100, respectively. Each volume is divided by the density to be Cp / (100 · Dp), (100−Cp) / (100 Ds). Therefore, the equation (1) is obtained.

  When the above formula (1) is developed, the formula (2) for obtaining the particle concentration of the light adjusting dispersion liquid is obtained.

  At this time, Dsus and Ds can be measured using a density meter, but it is difficult to measure Dp which is the density of the solid. However, if the concentration of the light adjustment particle dispersion liquid as an appropriate reference is arbitrarily determined in the expression for obtaining the light adjustment particle density, such as the following expression (3) obtained by developing the expression (2), the light adjustment as a reference When the particle density is obtained and the value is substituted into the equation (2), the particle concentration is obtained. The particle concentration obtained here is a relative value when the standard is determined and cannot be said to be a true value. However, since a relative comparison is possible, there is virtually no problem. The concentration of the light adjustment particle dispersion used as a reference is, for example, the NV value (the weight ratio of the light adjustment particle dispersion after drying / the weight of the light adjustment dispersion before drying). Mass) may be employed.

  The content of the light control particles in the light control suspension can be appropriately selected according to the purpose. From the viewpoint of heat resistance and dimming performance, the content in the light adjusting suspension is preferably 0.1% by mass to 30% by mass, and more preferably 0.5% by mass to 25% by mass. Preferably, it is more preferably 1% by mass to 15% by mass, and particularly preferably 2% by mass to 10% by mass.

(Plasticizer)
The light adjusting suspension in which the light adjusting particles are dispersed contains the above-mentioned specific copolymer as a flowable dispersion medium, but may further contain at least one plasticizer as required. Thereby, the viscosity of light adjustment suspension can be reduced more.
Any plasticizer may be used as long as it plays the role of dispersing the light control particles in a flowable state in the same manner as the above-described specific copolymer. Plasticizers include alkyl phthalates such as dioctyl phthalate, diisooctyl phthalate, dibutyl phthalate, and butyl octyl phthalate, isophthalic acid alkyl esters such as dioctyl isophthalate, butyl oleate, and oleic acid-n-propyl. Oleic acid alkyl esters such as dioctyl adipate, alkyl benzoates such as diethylene glycol dibenzoate, octyl trimellitic acid, dodecyl trimellitic acid, and isodecyl trimellitic acid .
There is no restriction | limiting in particular in the ratio of a specific copolymer and a plasticizer as a dispersion medium in light control suspension liquid, It can select suitably as needed. For example, the ratio of the specific copolymer in the total amount of the specific copolymer and the plasticizer is preferably 3% by mass or more, and more preferably 5% by mass or more.

The light adjusting suspension is prepared by mixing a light adjusting particle dispersion containing a solvent, the specific copolymer, and, if necessary, the plasticizer by a commonly used method, and then adjusting the light adjusting particles to a desired concentration. The solvent can be prepared by removing at least a part of the solvent.
Specifically, as a method for removing the solvent, there is a method in which the light control particle dispersion liquid having a predetermined concentration, the specific copolymer, and a plasticizer contained as necessary are mixed, and then the solvent is distilled off under reduced pressure while heating. preferable. When an aspirator, diaphragm type or oil rotary type pump is connected to the rotary evaporator and the pressure is reduced, the solvent can be distilled off efficiently. Further, the concentration of the light control particle dispersion can be calculated as described above.

[Polymer medium]
Examples of the polymer medium (hereinafter, also simply referred to as “polymer medium”) that can be cured by energy ray irradiation contained in the light control material include (A) a resin having a (meth) acryloyl group and (B) a photopolymerization initiator. And those that are cured by irradiating energy rays such as ultraviolet rays, visible rays, and electron beams. (A) As a resin having a (meth) acryloyl group, a polysiloxane resin, an acrylic resin, a polyester resin, or the like is preferable from the viewpoints of ease of synthesis, light control performance, durability, and the like. These resins are substituted with (meth) acryloyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, hexyl group, An alkyl group such as a cyclohexyl group; an aryl group such as a phenyl group and a naphthyl group; and the like are preferable in terms of light control performance, durability, and the like. The (meth) acryloyl group means at least one of an acryloyl group and a methacryloyl group.

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

  Examples of the polysiloxane resin having a (meth) acryloyl group (hereinafter also simply referred to as “polysiloxane resin”) include, for example, both-end silanol polydimethylsiloxane, both-end silanol polydiphenylsiloxane-dimethylsiloxane copolymer, and both-end silanol. 2-terminal silanol siloxane polymer such as polydimethyldiphenylsiloxane, trialkylalkoxysilane such as trimethylmethoxysilane, (meth) acryloyl group-containing silane compound such as (3-acryloxypropyl) methyldimethoxysilane, and the like, It is synthesized by a dehydration condensation reaction and a dealcoholization reaction in the presence of an organotin catalyst such as ethylhexanetin. Further, as the form of the polysiloxane resin, a solventless type is preferably used. That is, when a solvent is used for the synthesis of the polysiloxane resin, it is preferable to remove the solvent after the synthesis reaction.

  The content of the structural unit having a (meth) acryloyl group in the polysiloxane resin is preferably 1.3% by mass to 5.0% by mass of the entire polysiloxane resin, and 1.5% by mass to More preferably, it is 4.5 mass%.

  In order to set the content of the structural unit having a (meth) acryloyl group in the polysiloxane resin to 1.3% by mass to 5.0% by mass of the entire polysiloxane resin, the production of the polysiloxane resin is performed. In the method, the total amount of the (meth) acryloyl group-containing silanol compound in the condensation raw material of the polysiloxane resin (at least one of the silanol group-containing siloxane monomer and oligomer, the (meth) acryloyl group-containing silanol compound, and an end cap to be added as necessary It can be achieved by adjusting the content to 2.3 to 6.9% by mass of the total amount of the agent.

  The weight average molecular weight of the polysiloxane resin is preferably 35,000 to 60,000, more preferably 37,000 to 58,000, and further preferably 40,000 to 55,000. preferable. In order to make the weight average molecular weight of the polysiloxane resin within the above range, for example, when the weight average molecular weight is measured by gel permeation chromatography (GPC) in the polymerization process, the weight average molecular weight becomes 35,000-60,000. What is necessary is just to stop a polymerization reaction. The weight average molecular weight is given as a value converted from a calibration curve using standard polystyrene with respect to the molecular weight distribution measured by GPC.

  The acrylic resin having the (meth) acryloyl group (hereinafter also simply referred to as “acrylic resin”) can be obtained, for example, as follows. (Meth) acrylic acid alkyl ester, (meth) acrylic acid aryl ester, (meth) acrylic acid benzyl, main chain forming monomers such as styrene, (meth) acrylic acid, hydroxyethyl (meth) acrylate, (meth) A prepolymer is once synthesized by copolymerizing a functional group-containing monomer for introducing a (meth) acryloyl group such as isocyanate ethyl acrylate and glycidyl (meth) acrylate. Next, monomers such as glycidyl (meth) acrylate, isocyanate ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid and the like to be reacted with the (meth) acryloyl group-introducing functional group of this prepolymer Can be obtained by addition reaction to the prepolymer.

  Moreover, there is no restriction | limiting in particular as a polyester resin which has the said (meth) acryloyl group, What can be easily manufactured by a well-known method is mentioned. For example, it can be obtained by copolymerizing a monomer capable of forming a polyester main chain and a monomer that can be copolymerized therewith and has a (meth) acryloyl group. Moreover, you may obtain by making the compound which has a functional group for (meth) acryloyl group introduction | transduction react with the prepolymer which has a polyester principal chain.

  The concentration of (meth) acryloyl group contained in the resin having (A) (meth) acryloyl group is obtained from the integral intensity ratio of hydrogen in NMR. In addition, 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 for 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. The photopolymerization initiator can be appropriately selected from commonly used compounds. Examples of the photopolymerization initiator include ketone compounds, phosphine oxide compounds, and oxime esters. Specifically, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propane-1- And bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropan-1-one, (1-hydroxycyclohexyl) phenyl ketone, and the like.

  (B) The content of the photopolymerization initiator is preferably 0.1 parts by mass to 20 parts by mass, and 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the resin (A). It is more preferable.

  The polymer medium may further contain an organic solvent-soluble resin or a thermoplastic resin as another resin in addition to the resin having the (A) (meth) acryloyl group. Examples of other resins include polyacrylic acid and polymethacrylic acid. The weight average molecular weight of other resins is not particularly limited. For example, it can be set to 1,000 to 100,000. The weight average molecular weight is given as a value converted from a calibration curve using standard polystyrene with respect to the molecular weight distribution measured by gel permeation chromatography.

  In the polymer medium, additives such as a coloring inhibitor such as dibutyltin dilaurate may be added as necessary. Furthermore, the polymer medium may contain a solvent. Examples of the solvent include ether solvents such as tetrahydrofuran; hydrocarbon solvents such as toluene, heptane, and cyclohexane; alcohol solvents such as ethanol and methanol; ester solvents such as ethyl acetate, isoamyl acetate, and hexyl acetate;

  The light control material of the present invention can be prepared by mixing the light control suspension and the polymer medium. The mixing ratio of the light adjusting suspension and the polymer medium can be appropriately selected according to the purpose. For example, the light adjusting suspension is preferably contained in an amount of 1 to 100 parts by weight, more preferably 4 to 70 parts by weight, and more preferably 6 to 60 parts by weight with respect to 100 parts by weight of the polymer medium. It is more preferable to include a part, and it is particularly preferable to include 8 to 50 parts by mass.

<Light control film>
The light control film of the present invention has two conductive resin base materials and a light control layer sandwiched between the two conductive resin base materials and formed using the light control material. The light control material is formed with a light control layer including a resin matrix formed from a polymer medium and a light control suspension dispersed in the resin matrix.
By forming the light control layer from the light control material, it is possible to configure a light control film having excellent low-temperature response.

(Conductive resin base material)
The conductive resin substrate is generally configured by having a conductive film on a resin substrate. In particular, the conductive resin base material has a surface resistivity in which a transparent conductive film (ITO, SnO ₂ , In ₂ O ₃ , organic conductive film, etc.) having a light transmittance of 80% or more is coated on the resin base material. Is preferably 3Ω / □ to 3000Ω / □. The surface resistivity can be measured, for example, by a four-probe method using a low resistivity meter (trade name: Loresta EP, manufactured by Dia Instruments).

  The conductive resin substrate is preferably a transparent conductive resin substrate having a light transmittance of 80% or more, and more preferably a transparent conductive resin substrate having a light transmittance of 85% or more. The light transmittance can be measured according to the method for measuring the total light transmittance of JIS K7105.

  As the resin substrate, for example, a polymer film or the like can be used. Examples of the polymer film include polyester films such as polyethylene terephthalate, polyolefin films such as polypropylene, polyvinyl chloride, acrylic resin films, polyether sulfone films, polyarylate films, polycarbonate films, and the like. Among them, a polyethylene terephthalate film is preferable because it is excellent in transparency and excellent in moldability, adhesiveness, workability, and the like.

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

As the conductive resin substrate, a conductive resin substrate in which an insulating layer having a thickness of about several nm to 1 μm is formed on the conductive film may be used. By further including an insulating layer, even when the interval between the conductive resin bases in the light control film is narrow, it is possible to prevent a short-circuit phenomenon that occurs due to mixing of foreign substances.
When the light control film of the present invention is used for a reflective light control window (for example, a rear view mirror for automobiles), a conductive metal thin film such as aluminum, gold, or silver as a conductive film is used as a conductive film. It may be used.

  The light control film of the present invention is sandwiched between two transparent conductive resin substrates having a primer layer for improving adhesion to the light control layer, or a transparent conductive resin substrate having a primer layer And a transparent conductive resin base material having no primer layer may be sandwiched between two transparent conductive resin 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 includes a resin matrix and the light control suspension dispersed in the resin matrix. The resin matrix is obtained by curing a polymer medium (preferably an ethylenically unsaturated group-containing polymer compound) that can be cured by irradiation with energy rays contained in the light control material. The polymer medium and the dispersion medium (dispersion medium such as a copolymer and a plasticizer in the light control suspension) are the same when the polymer medium and its cured product and the dispersion medium are at least formed into a film. Use what can be phase-separated. It is preferable to use the polymer medium and the dispersion medium which are incompatible or partially compatible with each other in combination.

  In order to obtain a light control film, first, a liquid light control suspension is mixed with a polymer medium, and the light control suspension is a liquid mixture in which the light control suspension is dispersed in a droplet state in the polymer medium. Prepare the material. 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 control material is usually 1 part by mass to 100 parts by mass, preferably 4 parts by mass to 70 parts by mass, and more preferably 6 parts by mass to 60 parts by mass with respect to 100 parts by mass of the polymer medium. Prepare by mixing parts by mass.

  This light control material is apply | coated by the fixed thickness on the conductive layer of the said conductive resin base material, and an application layer is formed. For the application of the light modulating material, known coating means such as a bar coater, applicator, doctor blade, roll coater, die coater, and comma coater can be used. The light modulating material may be applied to the surface of the primer layer provided on the conductive resin base material, or when using a conductive resin base material that does not have a primer layer on one side, apply directly to the conductive layer. You can also. In addition, when apply | coating, you may dilute a light control material with a suitable solvent as needed. When using a solvent, it is preferable to apply a light-modulating material to the conductive resin substrate and then perform a drying treatment.

  Solvents used for application of the light-modulating material include ether solvents such as tetrahydrofuran; hydrocarbon solvents such as toluene, heptane and cyclohexane; alcohol solvents such as ethanol and methanol; ester solvents such as ethyl acetate, isoamyl acetate and hexyl acetate; Can be used. In order to form a light control layer in which a 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. A method of finely dispersing the light control suspension in the molecular medium, a phase separation method by polymerization of resin components in the polymer medium, a phase separation method by solvent volatilization, a phase separation method by temperature, and the like can be used.

  After applying the light-modulating material, or after removing the solvent contained in the light-modulating material as required, the polymer medium is cured by irradiating with 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 formed by curing the 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 droplet size (average droplet diameter) of the light control suspension dispersed in the resin matrix is usually 0.5 μm to 100 μm, preferably 0.5 μm to 20 μm, more preferably 1 μm. ~ 5 μm. 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. Etc. can be adjusted.

  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 50 droplet diameters arbitrarily selected, and calculating the average value thereof. be able to. 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.

  Thus, the light control film is obtained by sticking another conductive resin base material on the light control layer formed on the conductive resin base material.

  In addition, the light-modulating material is applied to the conductive resin base material at a constant thickness, and if necessary, the solvent in the light-controlling material is dried and removed, and then laminated with the other conductive resin base material. The light control layer can also be obtained by irradiating ultraviolet rays to cure the polymer medium to form a light control layer.

  Further, a light control layer may be formed on both conductive layers or primer layers of the two conductive resin substrates, and the light control layers may be laminated so that they are in close contact with each other.

  The thickness of the light control layer is preferably 5 μm to 1,000 μm, and more preferably 20 μm to 200 μm.

<Light control by light control film>
The light control film of this invention can adjust light transmittance arbitrarily by formation of an electric field. When the electric field is not formed, the light control film maintains a clear coloring state in which light scattering is suppressed, 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 into 1 second-50 second at the time of decoloring, and within 1 second-100 second at the time of coloring.

  Since the light control film of this invention contains the light control suspension containing a specific copolymer, it is excellent in the low temperature response in a low temperature environment. Specifically, the response time to ON / OFF of the electric field in an environment of −20 ° C. can be set to 1 second to 50 seconds or less when erasing, and 1 second to 100 seconds or less when coloring. Low temperature response can be achieved.

  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 technology, if a method using an emulsion using water is used, the liquid crystal often reacts with moisture and loses its light adjustment characteristics, and thus a film having the same characteristics is produced. 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 scattering is suppressed, and the coloring 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, it is accompanied by a change in color tone due to ultraviolet exposure and a decrease in variable capacity, and a voltage drop that occurs between the peripheral part and the central part of the conductive resin base material unique to large products. Response time difference is also eliminated.

  Next, the operation state of one aspect of the light control film of the present invention will be described with reference to FIGS. In FIGS. 2 and 3, as an example, a light control film including a conductive resin base material having a conductive layer 5 a and a resin base material 5 b is illustrated. FIG. 2 (a) is a schematic cross-sectional view of the light control film for explaining a state where the electric field of the light control film is not applied, and FIG. 2 (b) is an enlarged view of the light control suspension at this time. It is. Fig.3 (a) is a schematic sectional drawing explaining the state to which the electric field of the light control film is applied, FIG.3 (b) is an enlarged view in the light adjustment suspension at this time.

  When no electric field is applied, as shown in FIG. 2B, the light adjusting particles in the light adjusting suspension are directed in a random direction due to Brownian motion. Therefore, as shown in FIG. 2A, the light absorption of the light adjusting particles shows a clear coloring state due to the dichroic effect. In the state where the electric field is applied, as shown in FIG. 3B, the light adjusting particles in the droplet or the droplet connected body are arranged in parallel to the electric field. Thereby, as shown to Fig.3 (a), the light control film is changed into the state which can permeate | transmit the incident light 11 which is visible light.

  Further, since the light control film of the present invention is in a film state in which the light control layer is cured, the problem of the light control glass according to the prior art that uses the liquid light control suspension as it is is solved. That is, due to the difficulty in injecting a liquid suspension between two conductive resin base materials, the expansion phenomenon of the lower part due to the water pressure difference between the upper and lower parts of the product, and the change in the base interval due to the external environment such as wind pressure The leakage of the light-modulating material due to local hue change and the destruction of the sealing material between the conductive resin base materials is 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, the light control function by light interception | blocking and permeation | transmission currently utilized as an operation principle with the existing liquid crystal display element is inadequate. However, such a problem can be solved by the light control film of 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 optical shutters, various indoor / outdoor advertisements and information signs, window glass for aircraft / railway vehicles / ships, window glass / back mirror / sunroof for automobiles, glasses, sunglasses, sun visors can do.

  As a method of applying the light control film of the present invention, the light control film can be used directly as it is. Depending on the application, for example, the light control film of the present invention may be used by being sandwiched between two base materials, or may be used by being attached to one side of the base material. As said base material, glass and the polymer film similar to the said resin base material can be used, for example.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Reference example>
(Preparation of light control particle dispersion for determination of reference particle density)
An 8.5 mass% iodine isoamyl acetate solution from iodine (JIS reagent special grade, Wako Pure Chemical Industries, Ltd.) and isoamyl acetate (reagent special grade, Wako Pure Chemical Industries, Ltd.), and nitrocellulose 1 / 4LIG An isoamyl acetate solution of 20.0 mass% nitrocellulose was prepared from (trade name: manufactured by Bergerac NC) and isoamyl acetate. Calcium iodide hydrate (chemical use, manufactured by Wako Pure Chemical Industries, Ltd.) was dried by heating, dehydrated and dissolved in isoamyl acetate to prepare a 20.9 mass% calcium iodide solution. A 20 L flask was equipped with a stirrer and a condenser, 6905 g of iodine solution and 8723 g of nitrocellulose solution were added, and the flask was heated at a water bath temperature of 35 to 40 ° C. The water ratio (% by mass) in the nitrocellulose solution was measured using Hiranuma Sangyo Co., Ltd., Hiranuma moisture measuring device AQ-7 (generating liquid: Hydranal Aqualite RS, counter electrode liquid: Aqualite CN). The amount of water in the nitrocellulose solution was 53.2 g from the added solution mass. After the temperature of the flask contents reached 35 to 40 ° C., 260 g of dehydrated methanol (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) and 55.6 g of purified water (manufactured by Wako Pure Chemical Industries, Ltd.) were added. And stirred. 1643 g of calcium iodide solution was added, and then 390 g of pyrazine-2,5-dicarboxylic acid (manufactured by Nikka Techno Service Co., Ltd.) was added. The water bath temperature was set to 42 ° C. to 44 ° C. and the mixture was stirred for 4 hours and then allowed to cool.
The resultant synthesis solution was centrifuged at 9260 G for 5 hours, and the supernatant was removed by inclining. To the precipitate remaining at the bottom, isoamyl acetate corresponding to 5 times the mass of the precipitate was added, and the precipitate was dispersed with ultrasound. Then, after centrifugation at 710 G for 10 minutes, the supernatant was centrifuged at 9260 G for 3 hours.
The supernatant was removed by inclining, and isoamyl acetate corresponding to 5 times the mass of the precipitate was added to the precipitate remaining at the bottom, and the precipitate was dispersed with ultrasonic waves to prepare a light control particle dispersion.

  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 350 nm, and an average aspect. The ratio was 7.0. In addition, in the observation by SEM, the average value of the major axis and the aspect ratio was obtained from 300 light adjusting particles.

(Determination of standard particle density)
When the density of the above-mentioned light control dispersion was measured at 25.00 ° C., it was 0.92854 g / cm ³ . When this dispersed liquid was weighed on a 1 g metal plate and dried at 120 ° C. for 1 hour, the mass was measured again, and the non-volatile fraction NV value, which is the mass ratio of non-volatile components in the light control dispersion, was determined. It was 98 mass%. When the non-volatile content ratio NV value is defined as the particle concentration, and the density 2.9722 g / cm ³ obtained by substituting the density value into the above-described equation (3) is set as the reference particle density, the particle concentration is obtained from the density below. All used this value.

<Example 1>
(Preparation of light control particle dispersion)
A light-adjusting particle dispersion was prepared in the same manner as in the above Reference Example except that a nitrocellulose solution having a water ratio of 0.68% by mass was used and that purified water added together with dehydrated methanol was 56.9 g. . The density of the prepared light adjustment particle dispersion was 0.90925 g / cm ³ and the particle concentration was 6.1005% by mass.

(Mixing of light control particles and plasticizer)
169.52 g of this light-adjusting particle dispersion and 100.72 g of isodecyl trimellitate (manufactured by Kao) were added to a 500 mL eggplant-shaped flask, set in a rotary evaporator, and slowly decompressed with an oil rotary pump while heating at 80 ° C., After the solvent was distilled off in about 45 minutes, the pressure reduction was continued as it was. After 1 hour from the start of the decompression, the degree of vacuum was confirmed to be 1000 Pa or less, and after 3 hours, the decompression and heating were stopped to dissolve. Next, isoamyl acetate in the same amount as the content weight was added to the flask, and the second dissolution was performed again by the same procedure to obtain a light control particle mixture having a particle concentration of 9.73% by mass. A light control particle mixture was obtained.

(Synthesis of Resin Dispersant (Specific Copolymer) [S-1])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 5 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), methacryl-terminated polydimethylsiloxane FM0711 (manufactured by Chisso America Inc., weight average molecular weight: 1,000) 150 g 17.5 g of 3-mercapto-1,2-propanediol (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.84 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. It isolate | separated into the upper layer and the lower layer, the solvent was distilled off under reduced pressure from the collect | recovered lower layer, and resin dispersing agent [S-1] was obtained.
The content molar ratio (first structural unit / second structural unit) of the first structural unit and the second structural unit in the obtained resin dispersant was 20/80. The obtained resin dispersant had a weight average molecular weight of 2,200 and a viscosity at 25 ° C. of 310 mPa · s.
The viscosity at 25 ° C. was measured using an E-type viscometer (model: RE-80U, manufactured by Toki Sangyo Co., Ltd.). The weight average molecular weight was measured under the following conditions.
(conditions)
Sample: 10 μL
Detector: manufactured by Hitachi, Ltd., RI-monitor, trade name “L-3000RI”
Integrator: Hitachi, Ltd., GPC integrator, product name “D-2200”
Pump: Hitachi, Ltd., trade name “L-6000”
Column: manufactured by Hitachi Chemical Co., Ltd., trade names “GL-R440”, “GL-R450”, “GL-R400M” are used in this order and used as eluent: tetrahydrofuran (THF)
Measurement temperature: 23 ° C
Flow rate: 1.75 mL / min

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. The mass ratio of the resin dispersant [S-1] in the mass excluding the particles from the light control suspension was 60.0%.

(Manufacture of polymer media)
In a four-necked flask equipped with a Dean-Stark trap, cooling tube, stirrer, and heating device, (3-acryloxypropyl) methyldimethoxysilane (trade name: KBM-5102, manufactured by Shin-Etsu Chemical Co., Ltd.) 150.0 g , 19.0 g of distilled water, 0.4 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 89 g of a mixed solvent of ethanol / methanol = 9/1 by mass ratio, heated to 65 ° C. and reacted for 5 hours. It was. After cooling the reaction solution to 40 ° C. or lower, the pressure was reduced to 300 Pa, the temperature was raised to 70 ° C., and the desolubilization step was performed for 2 hours. Then, it cooled to room temperature and obtained 140g 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 by the absorption intensity (A) of a peak derived from a hydroxyl group (near 3435 cm ⁻¹ ) and the absorption intensity of a peak derived from an alkoxy group (near 2835 cm ⁻¹ ) (B ) Conversion rate = A / (A + B) × 100. From the infrared spectroscopic measurement after conversion of dimethoxysilane to silanol, the absorption intensity (A) was Abs = 0.250, and the absorption intensity (B) was Abs = 0.221. Therefore, the conversion rate was 54.5%. And calculated.

  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 8. Terminal silanol polydimethyldiphenylsiloxane (trade name: X-21-3193B, manufactured by Shin-Etsu Chemical Co., Ltd.) 170.0 g, part of the methoxy group of KBM-5102 obtained above is converted to silanol. 0 g and 0.01 g of bis (2-ethylhexanoic acid) tin (trade name: KCS-405T, manufactured by Johoku Chemical Industry Co., Ltd.) were charged, and the reaction was performed by refluxing in heptane at 100 ° C. for 5 hours. After cooling the temperature to 50 ° C., 109.0 g of trimethylmethoxysilane (trade name: KBM-31, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was refluxed again 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. Then, 210 g of methanol and 90 g of ethanol were added and stirred for 20 minutes, and allowed to stand for 12 hours, after which the alcohol layer was removed. The pressure was reduced to 100 Pa, the temperature was raised to 115 ° C., and desolubilization treatment was performed for 5 hours to obtain 148.8 g of a polysiloxane resin having a weight average molecular weight of 46,700, a viscosity of 16,000 mPa · s, and a refractive index of 1.4744.

  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 constituting the polysiloxane was 4.2% by mass. Moreover, from the ethylenically unsaturated bond density | concentration, the content rate of 3-acryloxypropylmethylsiloxane structural unit of this resin was 1.9 mass%.

(Manufacturing example of light control material)
31.3 g of the above polymer medium, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by BASF Japan Ltd.) and 0.2 g of tetrahydrofuran (Wako Pure Chemicals, special grade) each 18.7 g of the light control suspension prepared above was weighed into a polycup and stirred to obtain a light control material.

(Preparation of light control film)
(Preparation of primer layer forming coating solution)
1.5% by mass of AY42-151 (material containing urethane (meth) acrylate containing pentaerythritol skeleton, trade name, Toray Dow Corning Co., Ltd.), 1-methoxy-2-propanol / isopropyl alcohol = 7 A mixed solvent of / 3 (mass ratio) was mixed so as to have a ratio of 98.5% by mass to prepare a primer layer forming coating solution.

(Manufacture of conductive resin substrate with primer layer)
From a PET film (300R, manufactured by Toyobo Co., Ltd., thickness 125 μm) having a surface electrical resistance value of 200Ω / □ to 700Ω / □ coated with a transparent conductive film (thickness 30 nm) of ITO (indium tin oxide) On the conductive layer of the transparent conductive resin substrate, the primer layer forming coating solution was applied over the entire surface using a microgravure method (mesh # 150). After drying sequentially under the conditions of 50 ° C./30 seconds, 60 ° C./30 seconds, and 70 ° C./1 minute, photocuring was performed with UV irradiation 4000 mJ / cm ² (metal halide lamp) to form a primer layer on the conductive layer. . The average thickness of the obtained primer layer was 74 nm. Two conductive resin substrates having this primer layer were produced.
In addition, the thickness of the primer layer was measured and calculated as an arithmetic average value of five thicknesses measured using an instantaneous spectrophotometer F-20 (manufactured by Filmetrics Co., Ltd.).

On the primer layer of the conductive resin substrate with the primer layer obtained in the above-mentioned “Manufacture of the conductive resin substrate with the primer layer”, the entire surface of the light control material obtained in the “Manufacturing example of the light control material” is applied. did. Subsequently, the same transparent conductive resin base material on which a primer layer was similarly formed was laminated and adhered so that the transparent conductive film faced the coating layer of the light control material. Finally, using a metal halide lamp, ultraviolet light of 4000 mJ / cm ² was irradiated from the polyester film side of the laminated transparent conductive resin base material, and the light-adjusting suspension was applied to the ultraviolet light-cured resin matrix as spherical droplets. A light-modulating film having a thickness of 330 μm to 350 μm in which a light-modulating layer having a thickness of 90 μm to 98 μm formed in a dispersed manner was sandwiched between transparent conductive resin substrates was produced.

(Measurement of transmittance of light control film)
Using a spectroscopic color difference meter SZ-Σ90 (manufactured by Nippon Denshoku Industries Co., Ltd.), the Y value (%) measured with an A light source and a viewing angle of 2 degrees was defined as light transmittance. The light transmittance was measured when an electric field was applied and when it was not applied. Further, when an electric field is applied, _T on (%) transmittance of the time of application of 400Hz AC voltage (effective value) 100V, _T off (%) when no electric field is applied, the transmittance difference [Delta] T (%) = _{T on} (%) _- T and _{off (%), ΔT 0 (} %) 60 seconds after application of value was 55.0% when measured. After this light control film was stored at 110 ° C. for 2 hours, the ΔT ₁ (%) value was similarly measured and found to be 46.8%. Therefore, in this light control film, ΔT retention at 2 hours at 110 ° C. = ΔT ₀ / ΔT ₁ = 85.1%.

(Low temperature response evaluation)
The low temperature response was evaluated by measuring the response time as follows. The transmittance when no electric field was applied was 0%, and the transmittance when the transmittance became constant after the electric field was applied was 100%. Applying an electric field (from OFF to ON) to the time until the transmittance is 0% to 80% by _{t on,} turn off the voltage from the state of applying the voltage (to OFF from ON), the transmittance is 100% The time until _reaching 20% was defined as t _off .
When the response time was measured as described above at a temperature of −20 ° C., t _on was 15 seconds (s), and t _off was 60 seconds (s). The results are summarized in Table 1.

<Example 2>
(Synthesis of resin dispersant [S-2])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 5 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), 150 g of methacryl-terminated polydimethylsiloxane FM0721 (manufactured by Chisso America Inc., weight average molecular weight: 5,000) 17.5 g of 3-mercapto-1,2-propanediol (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.84 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. It isolate | separated into the upper layer and the lower layer, the solvent was distilled off under pressure reduction from the collect | recovered lower layer, and resin dispersing agent [S-2] was obtained.
The resulting resin dispersant had a weight average molecular weight of 11,000 and a viscosity at 25 ° C. of 950 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. Of the mass excluding the particles from the light control suspension, the mass ratio of the resin dispersant [S-2] was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 51.3%. After the light control film was stored at 110 ° C. for 2 hours, the ΔT ₁ (%) value was measured in the same manner to be 43.8%. Therefore, the ΔT retention at 110 ° C. for 2 hours in this light control film was 85.3%.

(Low temperature response evaluation)
_{T on} at a temperature -20 ° C. is _{29s, t off} was 89 s.

<Example 3>
(Synthesis of resin dispersant [S-3])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 5 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical Co., Ltd.), methacryl-terminated polydimethylsiloxane X-22-174DX (manufactured by Shin-Etsu Silicone, weight average molecular weight: 4,600) ) 150 g, 17.6 g of 3-mercapto-1,2-propanediol (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.85 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The solvent was distilled off from the recovered lower layer under reduced pressure to obtain a resin dispersant (dispersed polymer [S-3]).
The obtained resin dispersant had a weight average molecular weight of 6,200 and a viscosity at 25 ° C. of 280 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. Of the mass excluding the particles from the light control suspension, the mass ratio of the resin dispersant [S-3] was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 52.2%. The ΔT ₁ (%) value was measured in the same manner after storing this light control film at 110 ° C. for 2 hours, and it was 45.0%. Therefore, the ΔT retention of this light control film at 110 ° C. for 2 hours was 86.2%.

(Low temperature response evaluation)
At a temperature of −20 ° C., t _on was 13 s and t _off was 51 s.

<Example 4>
(Synthesis of resin dispersant [S-4])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 10 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical Co., Ltd.), methacryl-terminated polydimethylsiloxane X-22-174DX (manufactured by Shin-Etsu Silicone, weight average molecular weight: 4,600) ) 150 g, 17.6 g of 3-mercapto-1,2-propanediol (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.85 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. It isolate | separated into the upper layer and the lower layer, the solvent was distilled off under reduced pressure from the collect | recovered lower layer, and resin dispersing agent [S-4] was obtained.
The obtained resin dispersant had a weight average molecular weight of 7,600 and a viscosity at 25 ° C. of 520 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. The mass ratio of the resin dispersant (dispersed polymer [S-4]) in the mass excluding the particles from the light control suspension was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 56.4%. The ΔT ₁ (%) value was measured in the same manner after storing this light control film at 110 ° C. for 2 hours and found to be 49.1%. Therefore, the ΔT retention of this light control film at 110 ° C. for 2 hours was 87.1%.

(Low temperature response evaluation)
At a temperature of −20 ° C., t _on was 20 s and t _off was 69 s.

<Example 5>
(Synthesis of resin dispersant [S-5])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 6.5 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), methacryl-terminated polydimethylsiloxane FM0711 (manufactured by Chisso America Inc., weight average molecular weight: 1,000) ) 150 g, 18.9 g of hexyl mercaptan (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.84 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The solvent was distilled off from the recovered lower layer under reduced pressure to obtain a resin dispersant (dispersed polymer [S-5]).
The obtained resin dispersant had a weight average molecular weight of 2,500 and a viscosity at 25 ° C. of 270 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. The mass ratio of the resin dispersant [S-5] in the mass excluding the particles from the light control suspension was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 53.0%. The ΔT ₁ (%) value was measured in the same manner after storing this light control film at 110 ° C. for 2 hours, and it was 45.1%. Therefore, the ΔT retention of this light control film at 110 ° C. for 2 hours was 85.1%.

(Low temperature response evaluation)
At a temperature of −20 ° C., t _on was 12 s and t _off was 50 s.

<Example 6>
(Synthesis of resin dispersant [S-6])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 10.5 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), 150 g of FM0711 (manufactured by Chisso America Inc., weight average molecular weight: 1,000), hexyl mercaptan 18.9 g (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.85 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The solvent was distilled off from the recovered lower layer under reduced pressure to obtain a resin dispersant (dispersed polymer [S-3]).
The obtained resin dispersant had a weight average molecular weight of 2,400 and a viscosity at 25 ° C. of 350 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. Of the mass excluding the particles from the light control suspension, the mass ratio of the resin dispersant [S-6] was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 52.8%. The ΔT ₁ (%) value was measured in the same manner after storing this light control film at 110 ° C. for 2 hours, and it was 44.8%. Therefore, the ΔT retention of this light control film at 110 ° C. for 2 hours was 84.8%.

(Low temperature response evaluation)
_{T on} at a temperature -20 ° C. is _{17s, t off} was 63s.

<Example 7>
(Synthesis of resin dispersant [S-7])
160 g of toluene (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.), 4.0 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), FM0721 (manufactured by Chisso America Inc., weight average molecular weight: 5,000) 150 g, hexyl mercaptan 18.9 g (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.85 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. It isolate | separated into the upper layer and the lower layer, the solvent was distilled off under pressure reduction from the collect | recovered lower layer, and resin dispersing agent [S-3] was obtained.
The weight average molecular weight of the obtained resin dispersant was 9,500, and the viscosity at 25 ° C. was 890 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. The mass ratio of the resin dispersant [S-7] in the mass excluding the particles from the light control suspension was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 51.9%. The ΔT ₁ (%) value was measured in the same manner after storing this light control film at 110 ° C. for 2 hours, and it was 44.2%. Therefore, the ΔT retention at 110 ° C. for 2 hours in this light control film was 85.2%.

(Low temperature response evaluation)
At a temperature of −20 ° C., t _on was 27 s and t _off was 85 s.

<Example 8>
(Synthesis of resin dispersant [S-8])
160 g of toluene (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.), 4.0 g of 2-hydroxyethyl methacrylate (Kyoeisha Chemical), methacryl-terminated polydimethylsiloxane X-22-174DX (manufactured by Shin-Etsu Silicone, weight average molecular weight: 4) , 600) 150 g and 18.9 g of hexyl mercaptan (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) were added to a three-necked flask and heated to 80 ° C. with stirring in a nitrogen atmosphere. After 5 hours, 1.85 g of azoisobutyronitrile (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and the whole amount was added dropwise. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. It isolate | separated into the upper layer and the lower layer, the solvent was distilled off under pressure reduction from the collect | recovered lower layer, and resin dispersing agent [S-3] was obtained.
The obtained resin dispersant had a weight average molecular weight of 6,000 and a viscosity at 25 ° C. of 240 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. The mass ratio of the resin dispersant [S-8] out of the mass excluding the particles from the light control suspension was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 53.1%. After the light control film was stored at 110 ° C. for 2 hours, the ΔT ₁ (%) value was measured in the same manner to be 46.2%. Therefore, the ΔT retention at 110 ° C. for 2 hours in this light control film was 87.0%.

(Low temperature response evaluation)
_{T on} at a temperature -20 ° C. is _{10s, t off} was 47s.

<Comparative Example 1>
(Synthesis of Comparative Resin Dispersant [R-1])
164 g of toluene (reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.), dodecyl methacrylate 231.4 g (Kyoeisha Chemical), 2-hydroxyethyl methacrylate (reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.) 7.56 g, 18.9 g of hexyl mercaptan (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to a three-necked flask and heated to 60 ° C. with stirring in a nitrogen atmosphere. After 1 hour, 1.84 g of azoisobutyronitrile (reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 80 g of toluene, and then the whole amount was dropped. After heating for 21 hours, the mixture was heated to 115 ° C. and stirred for 2 hours. Then, the pressure was reduced and the solvent was distilled off. To this was added 200 g of methanol, transferred to a separatory funnel, shaken vigorously and allowed to stand for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. The mixture was separated into an upper layer and a lower layer, and the lower layer was transferred to a separatory funnel, 200 g of methanol was added and shaken vigorously, and left for 30 minutes. After separating into an upper layer and a lower layer and distilling off the solvent from the recovered lower layer under reduced pressure, short-path distillation purification was performed at 110 Pa at 200 ° C. to obtain a resin dispersant [R-1]. The molar ratio of the methacrylic acid ester having a hydroxy group and the methacrylic acid ester having an alkyl group was 6:94.
The obtained resin dispersant had a weight average molecular weight of 3,600 and a viscosity at 25 ° C. of 2,000 mPa · s.

(Preparation of light control suspension)
15.00 g of the light adjusting particle mixed solution and 22.5 g of the resin dispersant were weighed into a polycup and stirred to obtain a light adjusting suspension. Of the mass excluding the particles from the light control suspension, the mass ratio of the resin dispersant [R-1] was 60.0%.

(Preparation of light control material, preparation of light control film, measurement of transmittance)
A light control material was prepared in the same manner as in Example 1 except that this light control suspension was used, a light control film was prepared using the light control material, and the ΔT ₀ (%) value was measured. However, it was 52.2%. After the light control film was stored at 110 ° C. for 2 hours, the ΔT ₁ (%) value was measured in the same manner to be 43.9%. Therefore, the ΔT retention of this light control film at 110 ° C. for 2 hours was 84.1%.

(Low temperature response evaluation)
_{T on} at a temperature -20 ° C. is _{62s, t off} was 235s.

  As mentioned above, it turns out that the light control film prepared using the light control material of this invention is excellent in the response speed in a low-temperature environment. Furthermore, it turns out that the outstanding heat resistance is shown.

DESCRIPTION OF SYMBOLS 1 Light control layer 2 Resin matrix 3 Droplet 4 Conductive resin base material 5a Conductive film 5b Resin base material 6 Primer layer 7 Power supply 8 Switch 9 Dispersion medium 10 Light adjustment particle 11 Incident light

Claims (6)

A polymer medium curable by energy ray irradiation;
A copolymer that is dispersed in the polymer medium and includes a first structural unit derived from a (meth) acrylate having a hydroxy group and a second structural unit derived from a (meth) acrylate having a polysiloxane structure; and A light control suspension containing light control particles;
Only including,
The light control material whose ratio of said structural unit other than said 1st structural unit and said 2nd structural unit in the said copolymer is 20 mol% or less .   2. The copolymer according to claim 1, wherein a molar ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) is 10/90 to 70/30. Dimmable material.   The light control material according to claim 1, wherein the copolymer has an alkyl sulfide structure having a hydroxy group at least at one of a β-position and a γ-position at a terminal. Two conductive resin base materials, and a light control layer sandwiched between the two conductive resin base materials,
The light control layer is dispersed in the resin matrix, a first structural unit derived from a (meth) acrylate having a hydroxy group and a second (meth) acrylate derived from a (meth) acrylate having a polysiloxane structure copolymer including a structural unit, and a light control suspension containing light control particles, only including,
The light control film whose ratio of said structural unit other than said 1st structural unit and said 2nd structural unit in the said copolymer is 20 mol% or less .   5. The copolymer according to claim 4, wherein the copolymer has a molar ratio of the first structural unit to the second structural unit (first structural unit / second structural unit) of 10/90 to 70/30. Light control film.   The light control film according to claim 4, wherein the copolymer has an alkyl sulfide structure having a hydroxy group at least at one of a β-position and a γ-position at a terminal.